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1

Astaxanthin formation by the yeast Phaffia rhodozyma on molasses  

Microsoft Academic Search

Summary Phaffia rhodozyma grown on 7–10% B or C garde molasses contained 2 to 3 times more astaxanthin than reported earlier for this red yeast. Yield of astaxanthin with 10% molasses as fermentation substrate was 15.3 µg\\/ml which was about 3 times higher than with glucose and 2 times higher than with a sugar blend representative of the molasses.

N. F. Haard

1988-01-01

2

Efficient Transformation of the Astaxanthin-Producing Yeast Phaffia Rhodozyma  

Microsoft Academic Search

An efficient transformation system for the astaxanthin-producing yeast Phaffia rhodozyma was developed based on electroporation that routinely yields approximately 1000 transformants per µg of plasmid DNA. The high transformation efficiency depends on vector integration in the ribosomal DNA (rDNA) and the presence of the homologous glycolytic glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter and terminator to drive the expression of the transposon Tn5

Jan Wery; Jan C. Verdoes; Albert J. J. van Ooyen

1998-01-01

3

Monocyclic carotenoid biosynthetic pathway in the yeast Phaffia rhodozyma ( Xanthophyllomyces dendrorhous)  

Microsoft Academic Search

The biosynthetic pathway of monocyclic carotenoids in the yeast Phaffia rhodozyma was studied by identifying carotenoids, applying inhibitors of carotenoid synthesis, and analyzing the carotenoids in carotenogenic mutants. Two carotenoids, torulene and 3,3?-dihydroxy-?,?-carotene-4,4?-dione (DCD), were identified from the yeast. Piperonyl butoxide inhibited dehydrogenation of carotenes and caused accumulation of neurosporene, lycopene, ?-carotene, and ?-zeacarotene. Yellow mutants of P. rhodozyma produced

Gil-Hwan An; Myung-Haing Cho; Eric A. Johnson

1999-01-01

4

21 CFR 73.355 - Phaffia yeast.  

Code of Federal Regulations, 2013 CFR

...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 the yeast Phaffia rhodozyma. (2) Phaffia...

2013-04-01

5

21 CFR 73.355 - Phaffia yeast.  

Code of Federal Regulations, 2010 CFR

...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 the yeast Phaffia rhodozyma. (2) Phaffia...

2010-04-01

6

21 CFR 73.355 - Phaffia yeast.  

Code of Federal Regulations, 2010 CFR

...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 the yeast Phaffia rhodozyma. (2) Phaffia...

2009-04-01

7

Biogeography, Host Specificity, and Molecular Phylogeny of the Basidiomycetous Yeast Phaffia rhodozyma and Its Sexual Form, Xanthophyllomyces dendrorhous  

Microsoft Academic Search

Phaffia rhodozyma (sexual form, Xanthophyllomyces dendrorhous) is a basidiomycetous yeast that has been found in tree exudates in the Northern Hemisphere at high altitudes and latitudes. This yeast produces astaxanthin, a carotenoid pigment with biotechnological importance because it is used in aquaculture for fish pigmentation. We isolated X. dendrorhous from the Southern Hemisphere (Patagonia, Argentina), where it was associated with

Diego Libkind; Alejandra Ruffini; Maria van Broock; Leonor Alves; JosePaulo Sampaio

2007-01-01

8

The Colony Color Range of Yeasts Xanthophyllomyces dendrorhous and Phaffia rhodozyma and Wild Types and Carotene Mutants  

NSDL National Science Digital Library

This image shows several Xanthophyllomyces dendrorhous and Phaffia rhodozyma wild-type and mutant colonies after cells were grown for 120 hours in YM agar at 19°C. It is easy to appreciate how different end products in the yeast carotene pa

American Society For Microbiology;

2004-04-07

9

[Relationship between astaxanthin production and the intensity of anabolic processes in the yeast Phaffia rhodozyma].  

PubMed

The astaxanthin synthesis in the yeast Phaffia rhodozyma was shown to depend on the rate of growth occurring in the first two days of cultivation. The growth rate of the yeast culture studied was preset by the cultivation conditions, among which the C:N ratio was decisive. The intense anabolic processes coupled with active culture growth during the first 24 h significantly inhibited the synthesis of the key enzymes involved in astaxanthin synthesis, which led to a marked decrease in the carotenoid production. It was demonstrated that for the maximum yield of astaxanthin to be obtained from 11 of nutrient medium, it is necessary to carry out cultivation, beginning with the first day, at a growth rate significantly lower than mu(max). The optimum budding rate of the mutant strain Ph. rhodozyma VKPM Y-2409 consistent with the maximum astaxanthin synthesis was determined. The specific astaxanthin productivity of the strain studied was about 7.0 mg/g of dry biomass at a budding rate of <0.5. PMID:15688933

Vustin, M M; Belykh, E N; Kishilova, S A

10

Metabolic network analysis on Phaffia rhodozyma yeast using 13C–labeled glucose and gas chromatography-mass spectrometry  

Microsoft Academic Search

Carotenoid production by microorganisms, as opposed to chemical synthesis, could fulfill an ever-increasing demand for ‘all natural’ products. The yeast Phaffia rhodozyma has received considerable attention because it produces the red pigment astaxanthin, commonly used as an animal feed supplement. In order to have a better understanding of its metabolism, labeling experiments with [1-13C]glucose were conducted with the wildtype strain

Christopher Cannizzaro; Bjarke Christensen; Jens Nielsen; Urs von Stockar

2004-01-01

11

A factorial approach for a sugarcane juice-based low cost culture medium: increasing the astaxanthin production by the red yeast Phaffia rhodozyma  

Microsoft Academic Search

A sugarcane juice-based low cost culture medium was previously explored to produce the carotenoid pigment astaxanthin in liquid culture by the red yeast Phaffia rhodozyma (1300 7g astaxanthin\\/g of dry yeast and 6500 7g\\/l whole culture medium). Two peculiar limitations in Phaffia are growth temperature (7g\\/l) obtained was 23.0% but at the expense of 16.0% pigment content decrease (7g\\/g). In

J. A. Florêncio; C. R. Soccol; L. F. Furlanetto; T. M. B. Bonfim; N. Krieger; M. Baron; J. D. Fontana

1998-01-01

12

Biogeography, host specificity, and molecular phylogeny of the basidiomycetous yeast Phaffia rhodozyma and its sexual form, Xanthophyllomyces dendrorhous.  

PubMed

Phaffia rhodozyma (sexual form, Xanthophyllomyces dendrorhous) is a basidiomycetous yeast that has been found in tree exudates in the Northern Hemisphere at high altitudes and latitudes. This yeast produces astaxanthin, a carotenoid pigment with biotechnological importance because it is used in aquaculture for fish pigmentation. We isolated X. dendrorhous from the Southern Hemisphere (Patagonia, Argentina), where it was associated with fruiting bodies of Cyttaria hariotii, an ascomycetous parasite of Nothofagus trees. We compared internal transcribed spacer (ITS)-based phylogenies of P. rhodozyma and its tree host (Betulaceae, Corneaceae, Fagaceae, and Nothofagaceae) and found them to be generally concordant, suggesting that different yeast lineages colonize different trees and providing an explanation for the phylogenetic distance observed between the type strains of P. rhodozyma and X. dendrorhous. We hypothesize that the association of Xanthophyllomyces with Cyttaria derives from a previous association of the yeast with Nothofagus, and the sister relationship between Nothofagaceae and Betulaceae plus Fagaceae correlates with the phylogeny of X. dendrorhous strains originating from these three plant families. The two most basal strains of X. dendrorhous are those isolated from Cornus, an ancestral genus in the phylogenetic analysis of the host trees. Thus, we question previous conclusions that P. rhodozyma and X. dendrorhous represent different species since the polymorphisms detected in the ITS and intergenic spacer sequences can be attributed to intraspecific variation associated with host specificity. Our study provides a deeper understanding of Phaffia biogeography, ecology, and molecular phylogeny. Such knowledge is essential for the comprehension of many aspects of the biology of this organism and will facilitate the study of astaxanthin production within an evolutionary and ecological framework. PMID:17189439

Libkind, Diego; Ruffini, Alejandra; van Broock, Maria; Alves, Leonor; Sampaio, José Paulo

2006-12-22

13

Biogeography, Host Specificity, and Molecular Phylogeny of the Basidiomycetous Yeast Phaffia rhodozyma and Its Sexual Form, Xanthophyllomyces dendrorhous?  

PubMed Central

Phaffia rhodozyma (sexual form, Xanthophyllomyces dendrorhous) is a basidiomycetous yeast that has been found in tree exudates in the Northern Hemisphere at high altitudes and latitudes. This yeast produces astaxanthin, a carotenoid pigment with biotechnological importance because it is used in aquaculture for fish pigmentation. We isolated X. dendrorhous from the Southern Hemisphere (Patagonia, Argentina), where it was associated with fruiting bodies of Cyttaria hariotii, an ascomycetous parasite of Nothofagus trees. We compared internal transcribed spacer (ITS)-based phylogenies of P. rhodozyma and its tree host (Betulaceae, Corneaceae, Fagaceae, and Nothofagaceae) and found them to be generally concordant, suggesting that different yeast lineages colonize different trees and providing an explanation for the phylogenetic distance observed between the type strains of P. rhodozyma and X. dendrorhous. We hypothesize that the association of Xanthophyllomyces with Cyttaria derives from a previous association of the yeast with Nothofagus, and the sister relationship between Nothofagaceae and Betulaceae plus Fagaceae correlates with the phylogeny of X. dendrorhous strains originating from these three plant families. The two most basal strains of X. dendrorhous are those isolated from Cornus, an ancestral genus in the phylogenetic analysis of the host trees. Thus, we question previous conclusions that P. rhodozyma and X. dendrorhous represent different species since the polymorphisms detected in the ITS and intergenic spacer sequences can be attributed to intraspecific variation associated with host specificity. Our study provides a deeper understanding of Phaffia biogeography, ecology, and molecular phylogeny. Such knowledge is essential for the comprehension of many aspects of the biology of this organism and will facilitate the study of astaxanthin production within an evolutionary and ecological framework.

Libkind, Diego; Ruffini, Alejandra; van Broock, Maria; Alves, Leonor; Sampaio, Jose Paulo

2007-01-01

14

Metabolic network analysis on Phaffia rhodozyma yeast using 13C-labeled glucose and gas chromatography-mass spectrometry.  

PubMed

Carotenoid production by microorganisms, as opposed to chemical synthesis, could fulfill an ever-increasing demand for 'all natural' products. The yeast Phaffia rhodozyma has received considerable attention because it produces the red pigment astaxanthin, commonly used as an animal feed supplement. In order to have a better understanding of its metabolism, labeling experiments with [1-(13)C]glucose were conducted with the wildtype strain (CBS5905T) and a hyper-producing carotenoid strain (J4-3) in order to determine their metabolic network structure and estimate intracellular fluxes. Amino acid labeling patterns, as determined by GC-MS, were in accordance with a metabolic network consisting of the Embden-Meyerhof-Parnas pathway, the pentose phosphate pathway, and the TCA cycle. Glucose was mainly consumed along the pentose phosphate pathway ( approximately 65% for wildtype strain), which reflected high NADPH requirements for lipid biosynthesis. Although common to other oleaginous yeast, there was no, or very little, malic enzyme activity for carbon-limited growth. In addition, there was no evidence of phosphoketolase activity. The central carbon metabolism of the mutant strain was similar to that of the wildtype strain, though the relative pentose phosphate flux was lower and the TCA cycle flux in accordance with the biomass yield being lower. PMID:15491863

Cannizzaro, Christopher; Christensen, Bjarke; Nielsen, Jens; von Stockar, Urs

2004-10-01

15

Cultivation of the carotenoid-hyperproducing mutant 2A2N of the red yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) with molasses.  

PubMed

The carotenoid-hyperproducing mutant 2A2N of the yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) was cultivated using sugar beet blackstrap molasses. This molasses was composed of 70% (w/v) total solid and 50% (w/v) total sugar. Biomass yield (biomass/carbohydrate) significantly decreased at >5% (v/v) molasses. Atomic emission spectrometry revealed that Na and P were the limiting nutrients when molasses was used. Molasses (5%, v/v) containing urea (30 g/l molasses) and sodium phosphate (NaH2PO4, 5 g/l molasses) was formulated for biomass production by the mutant. The optimal pH for carotenoid production was 4.9 during the growth phase and 2.6-3.5 during the stationary phase. The three main sugars in molasses (sucrose, glucose, and fructose) were assimilated by the mutant but fructose was consumed slowly. When the formulated medium with pH 4.5-5.5 was used, the maximal biomass yield was 36 g/l (0.18 g of yeast l(-1)h(-1) and 40 mg of carotenoid l(-1)) in fed-batch pilot-scale 100-l cultivation. PMID:16233070

An, G H; Jang, B G; Cho, M H

2001-01-01

16

Production of carotenoids by Phaffia rhodozyma grown on media composed of corn wet-milling co-products  

Microsoft Academic Search

Summary Natural isolates of the carotenoid-producing yeastPhaffia rhodozyma were analyzed for their ability to grow and to produce carotenoids in culture media composed exclusively of co-products of corn wet-milling for fuel ethanol production. FiveP. rhodozyma strains were tested for biomass produced (dry weight) and carotenoid yield. Six co-products were examined, ranging in cost from approximately $0.02 per kg to $0.11

G. Thomas Hayman; Bruno M. Mannarelli; Timothy D. Leathers

1995-01-01

17

Impact of gamma rays on the Phaffia rhodozyma genome revealed by RAPD-PCR  

PubMed Central

Background and Objectives Phaffia rhodozyma is a red yeast which produces astaxanthin as the major carotenoid pigment. Astaxanthin is thought to reduce the incidence of cancer and degenerative diseases in man. It also enhances the immune response and acts as a free-radical quencher, a precursor of vitamin A, or a pigment involved in the visual attraction of animals as mating partners. The impact of gamma irradiation was studied on the Phaffia rhodozyma genome. Materials and Methods Ten mutant strains, designated Gam1-Gam10, were obtained using gamma irradiation. Ten decamer random amplified polymorphic DNA (RAPD) primers were employed to assess genetic changes. Results Nine primers revealed scorable polymorphisms and a total of 95 band positions were scored; amongst which 38 bands (37.5%) were polymorphic. Primer F with 3 bands and primer J20 with 13 bands produced the lowest and the highest number of bands, respectively. Primer A16 produced the highest number of polymorphic bands (70% polymorphism) and primer F showed the lowest number of polymorphic bands (0% polymorphism). Genetic distances were calculated using Jaccard's coefficient and the UPGMA method. A dendrogram was created using SPSS (version 11.5) and the strains were clustered into four groups. Conclusion RAPD markers could distinguish between the parental and the mutant strains of P. rhodozyma. RAPD technique showed that some changes had occurred in the genome of the mutated strains. This technique demonstrated the capability to differentiate between the parental and the mutant strains.

Najafi, N; Hosseini, Ramin; Ahmadi, AR

2011-01-01

18

Isolation of Phaffia rhodozyma Mutants with Increased Astaxanthin Content  

PubMed Central

Plating of the astaxanthin-producing yeast Phaffia rhodozyma onto yeast-malt agar containing 50 ?M antimycin A gave rise to colonies of unusual morphology, characterized by a nonpigmented lower smooth surface that developed highly pigmented vertical papillae after 1 to 2 months. Isolation and purification of the pigmented papillae, followed by testing for pigment production in shake flasks, demonstrated that several antimycin isolates were increased two- to fivefold in astaxanthin content compared with the parental natural isolate (UCD-FST 67-385). One of the antimycin strains (ant-1) and a nitrosoguanidine derivative of ant-1 (ant-1-4) produced considerably more astaxanthin than the parent (ant-1 had 800 to 900 ?g/g; ant-1-4 had 900 to 1,300 ?g/g; and 67-385 had 300 to 450 ?g/g). The mutant strains were compared physiologically with the parent. The antimycin mutants grew slower on ammonia, glutamate, or glutamine as nitrogen sources compared with the natural isolate and also had lower cell yields on several carbon sources. Although isolated on antimycin plates, they were found to be more susceptible to antimycin A, apparently owing to the spatial separation of the papillae from the agar. They were also more susceptible than the parent to the respiratory inhibitor thenoyltrifluoroacetone and were slightly more susceptible to cyanide, but did not differ from the natural isolate in susceptibility to azide. The antimycin-derived strains were also killed faster than the parent by hydrogen peroxide. The carotenoid compositions of the parent and the antimycin-derived strains were similar to those previously determined in the type strain (UCD-FST 67-210) except that two carotenoids not previously found in the type strain were present in increased quantities in the antimycin mutants and phoenicoxanthin was a minor component. The chemical properties of the unknown carotenoids suggested that the strains isolated on antimycin agar tended to oxygenate and desaturate carotene precursors to a greater extent than the parent. The physiology of the antimycin isolates and the known specificity of antimycin for cytochrome b in the respiratory chain suggests that alteration of cytochrome b or cytochrome P-450 components involved in oxygenation and desaturation of carotenes in mitochondria are affected, which results in increased astaxanthin production. These astaxanthin-overproducing mutants and more highly pigmented derivative strains could be useful in providing a natural source of astaxanthin for the pen-reared-salmon industry or for other farmed animals that contain astaxanthin as their principal carotenoid. Images

An, Gil-Hwan; Schuman, Donald B.; Johnson, Eric A.

1989-01-01

19

[Characterization and evaluation of an astaxanthin over-producing Phaffia rhodozyma].  

PubMed

We evaluated an astaxanthin overproducing Phaffia rhodozyma JMU-MVP14, and developed astaxanthin high-yielding fermentation process. We analyzed several fermentation parameters, i.e., biomass, astaxanthin and total carotenoids content to compare the characteristics of P rhodozyma JMU-MVP14 and the original strain through flask fermentation experiments. We conducted batch and fed-batch fermentation experiments in 7 L fermentor to investigate the effects of pH controlling models and feeding medium compositions on the production of astaxanthin. We further evaluated the capability and practical value of P rhodozyma JMU-MVP14 by fed-batch cultivation in the 1 m3 fermentor. Flask fermentation experiments revealed that P. rhodozyma JMU-MVP14 produced high yield of astaxanthin and carotenoids with specific productivity of astaxanthin and specific productivity of total carotenoids of 6.01 mg/g and 10.38 mg/g. Results of batch culture experiments in the 7 L fermentor showed that controlling the pH by ammonia auto-feeding was better than discontinuously adjusting pH value at 6.0 with regard to the high productivities of biomasses and astaxanthin. This P. rhodozyma strain synthesized astaxanthin partially linked to the growth with the Ks and pmax of 0.20 h ' and 21.73 g/L, respectively. Results of batch-fed fermentations in 7 L fermentor indicated that the complex feeding medium consisted of 50% glucose, 0.5% yeast extract and 0.3% corn steep syrup had lower astaxanthin productivity than the simple feeding medium containing only 50% glucose, which produced biomass, volumetric productivity of astaxanthin, volumetric productivity of total carotenoids, specific productivity of astaxanthin and total carotenoids at 32.81 g/L, 155.99 mg/L, 4.94 mg/g, 399.99 mg/L and 12.19 mg/g, respectively. As fed-batch cultured in 1 m3 fermentor, P rhodozyma JMU-MVP14 yielded 85.11 g/L of biomass, 279.96 mg/L of volumetric productivity of astaxanthin, 618.01 mg/L of volumetric productivity of total carotenoids, 3.29 mg/g of specific productivity of astaxanthin and 7.26 mg/g of specific productivity of total carotenoids. Additionally, P rhodozyma JMU-MVP14 cell contained 21.54% of protein, 41.34% of carbohydrate and 34.31% of lipid. These comprehensive results suggest that P. rhodozyma JMU-MVPl14 has great practical prosperity related to its strong ability to produce astaxanthin and good value byproducts. PMID:22016991

Ni, Hui; Hong, Qinglin; Xiao, Anfeng; Li, Lijun; Cai, Huinong; Su, Wenjin

2011-07-01

20

Singlet oxygen and peroxyl radicals regulate carotenoid biosynthesis in Phaffia rhodozyma.  

PubMed

Carotenoids have recently received considerable interest because of their potential in delaying or preventing degenerative diseases such as arteriosclerosis, cancer, and aging. In this study we show that the active oxygen species singlet oxygen (1O2) and peroxyl radicals differently affect carotenoid composition and biosynthesis in the yeast Phaffia rhodozyma. Photochemical generation of 1O2 with rose bengal or alpha-terthienyl induced carotenoid accumulation. In contrast, peroxyl radicals derived from t-butylhydroperoxide (tBOOH) or H2O2 decreased the content of astaxanthin and increased beta-carotene by approximately 4-fold, suggesting end product feedback regulation by astaxanthin or inhibition of biosynthetic enzymes. 14C labeling of carotenoids during oxidative stress supported the possibility of end product regulation. Carotenoids were bleached by 8 mM tBOOH within 6 h when carotenogenesis was inhibited by thymol. When treated with peroxides, a previously unreported pigment in P. rhodozyma was formed. The carotenoid had a mass of 580 Da and a molecular formula of C40H52O3. Chemical derivatizations combined with mass and absorbance spectroscopy tentatively identified the carotenoid as dehydroflexixanthin (3,1'-dihydroxy-2,3,3',4'-tetradehydro-1',2'-dihydro-beta,psi-caro tene-4-one). This study provides the first report of induction of astaxanthin biosynthesis by 1O2, probable feedback control by astaxanthin, and the oxidative degradation of astaxanthin to novel pigments in P. rhodozyma. PMID:7629161

Schroeder, W A; Johnson, E A

1995-08-01

21

Increased astaxanthin production by Phaffia rhodozyma mutants isolated as resistant to diphenylamine  

Microsoft Academic Search

To improve astaxanthin production by Phaffia rhodozyma, resistance to a carotenoid biosynthesis inhibitor was employed to screen higher astaxanthin producers. The wild type strain generated pinkish salmon-colored colonies due to the intracellular astaxanthin accumulation, but the colonies have turned white when grown in the presence of some of carotenoid biosynthesis inhibitors. Among the compounds tested, diphenylamine (DPA) was selected as

Namthip Chumpolkulwong; Toshihide Kakizono; Shiro Nagai; Naomichi Nishio

1997-01-01

22

ATP-citrate lyase activity and carotenoid production in batch cultures of Phaffia rhodozyma under nitrogen-limited and nonlimited conditions  

Microsoft Academic Search

ATP-citrate lyase (ACL) is the key cytoplasmic enzyme which supplies acetyl-CoA for fatty acids in oleaginous yeast. Although\\u000a it has been suggested that fatty acid and carotenoid biosynthesis may have a common source of acetyl-CoA in Phaffia rhodozyma, the source for carotenoids is currently unknown. The purpose of this work was to analyze the development of ACL activity\\u000a during batch

Cipriano Chávez-Cabrera; Zoila R. Flores-Bustamante; Rodolfo Marsch; María del Carmen Montes; Sergio Sánchez; Juan Carlos Cancino-Díaz; Luis Bernardo Flores-Cotera

2010-01-01

23

Presence of double-stranded RNA and virus-like particles in Phaffia rhodozyma  

Microsoft Academic Search

Four double-stranded RNA (dsRNA) molecules were isolated from Phaffia rhodozyma UCD 67-385. Their molecular sizes were approximately 4.3, 3.1, 0.9 and 0.75 kilobase pairs (kbp) as determined by agarose-gel electrophoresis and they were designated as L, M, S1 and S2, respectively. By differential centrifugation in sucrose gradients, these dsRNAs copurified with isometric virus-like particles 36 nm in diameter. A cured

Antonio Castillo; Víctor Cifuentes

1994-01-01

24

Effects of double-stranded RNA viruses on the reproduction of Phaffia rhodozyma.  

PubMed

DsRNA viruses were transferred from a virus-containing strain to a virus-free strain of Phaffia rhodozyma by protoplast fusion. The resulting new strain carried all three types of dsRNA of the virus-containing strain and had the electrophoretic karyotype of the virus-free strain. The effects of the dsRNA viruses on the host fitness were checked by following the asexual and the sexual reproductivity. The results demonstrated that viruses have no effect on the growth rate during the lag and log phases of the vegetative reproduction, but the maximum cell numbers in the stationary phase differ significantly. Inconclusive results were obtained as concerns the effects of viruses on the sexual reproduction. PMID:11426864

Pfeiffer, I; Litter, J; Pénzes, Z S; Kucsera, J

2001-01-01

25

Xanthophyllomyces dendrorhous (Phaffia rhodozyma) on stromata of Cyttaria hariotii in northwestern Patagonian Nothofagus forests.  

PubMed

The occurrence and distribution of Xanthophyllomyces dendrorhous associated with Cyttaria hariotii parasitizing three Nothofagus species (N. dombeyi, N. antarctica and N. pumilio) in northwestern Patagonia (Argentina), as well as the factors that may affect this distribution were herein studied. Between 2000 and 2007, samples were obtained from 18 different locations. Based on physiological tests and morphological characteristics of sexual structures, 72 isolates were identified as X. dendrorhous. Representative strains were studied by MSP-PCR fingerprinting and sequence analysis of the ITS region. MSP-PCR fingerprints were similar for the newly isolated strains, and were also identical to the profiles of the strains previously found in this region. Patagonian strains appear to be a genetically uniform and distinct population, supporting the hypothesis that the association with different host species has determined genetically distinct X. dendrorhous populations worldwide. X. dendrorhous was recovered from N. dombeyi and N. antarctica. Approximately half the sampling sites and samples were positive for X. dendrorhous, but the isolation recovery rate was low. X. dendrorhous was absent in the early stages of ascostromata maturation, becoming more abundant in later stages. The present work represents a step forward in the understanding of the natural distribution and ecology of this biotechnologically relevant yeast. PMID:22430994

Libkind, Diego; Tognetti, Celia; Ruffini, Alejandra; Sampaio, José Paulo; Van Broock, María

26

SINGLE-CELL PROTEIN FROM Xanthophyllomyces dendrorhous YEAST: CONTINUOUS FERMENTATION USING PEAT EXTRACT AS SUBSTRATE  

Microsoft Academic Search

The yeast Xanthophyllomyces dendrorhous (formerly Phaffia rhodozyma) is a promising microbial producer of the carotenoid astaxanthin. This is a carotenoid found in the flesh of salmon. There are several studies about the use of this yeast as a compound of salmon feed. Moreover an astaxanthin source, Xanthophyllomyces dendrorhous is a protein source. In this work, continuous fermentations of Xanthophyllomyces dendrorhous

M. Vázquez; F. Diniz; A. M. Martin

1996-01-01

27

Effect of supplementation of University of Wisconsin solution with glycoproteins from psychrophilic strains of yeast on hypothermic liver storage of rats.  

PubMed

Extracellular yeast glycoproteins (YG) produced by Rhodosporidium toruloides have been shown to increase the survival rate of different yeast species after storage in liquid nitrogen. The purpose of this study was to investigate the effect of YG on cold-stored rat livers. Water-soluble YG produced either by Phaffia rhodozyma (G3) or by Leucosporidium antarcticum (G4) were added to a modified University of Wisconsin solution (mUW) and used for cold storage (1 degree C) of isolated livers. The functional status of each liver was then assessed under conditions of 90-min normothermic reperfusion. The 46-h cold storage in mUW without G3 and G4 resulted in serious preservation-reperfusion injury of the liver. The addition of G3 to mUW for 46-h preservation of the liver resulted in significantly higher bile flow (4.32 +/- 0.35 vs 2.35 +/- 0.49 microliters/min/10 g at 75-90 min), higher portal blood flow (10.99 +/- 0.2 vs 4.78 +/- 1.07 ml/min/g at 90 min), lower liver weight after reperfusion (102.4 +/- 1.5 vs 116.7 +/- 6.6% of weight before preservation), and lower total tissue water after reperfusion (2.49 +/- 0.05 vs 2.92 +/- 0.13 g water/g dry weight). However, the activity of ALT, AST, and LDH in perfusate was not changed. The beneficial effect of G4 was less pronounced. The 24-h storage in mUW resulted in a significant increase of AST and LDH activity in perfusate; the addition of G3 to mUW for 24-h preservation did not affect these parameters. In conclusion, the addition of 0.05% G3 or G4 to mUW was only partially beneficial in improving rat liver preservation. PMID:8689892

Tilser, I; Breierová, E; Tichý, M; Skalská, H; Ettlerová, E

1996-06-01

28

An unusual Xanthophyllomyces strain from leaves of Eucalyptus globulus in Chile  

Microsoft Academic Search

Xanthophyllomyces sp. was isolated as an epiphytic red yeast from leaves of Eucalyptus glo-bulus in Concepción, Chile. Sexual reproduction was by basidiospores produced from one or rarely two metabasidia arising from a yeast cell without preceding paedogamy. The main carotenoid pigment was astaxanthin. This isolate did not cluster with the X. dendrorhous complex (including Phaffia rhodozyma) in ITS and 26S

Roland W. S. Weber; José Becerra; Mario J. Silva; Paolo Davoli

2008-01-01

29

Production and optimization of carotenoid-enriched dried distiller’s grains with solubles by Phaffia rhodozyma and Sporobolomyces roseus fermentation of whole stillage  

Microsoft Academic Search

Whole stillage—a co-product of grain-based ethanol—is used as an animal feed in the form of dried distiller’s grain with solubles\\u000a (DDGS). Since animals cannot synthesize carotenoids and animal feed is generally poor in carotenoids, about 30–120 ppm of\\u000a total carotenoids are added to animal feed to improve animal health, enhance meat color and quality, and increase vitamin\\u000a A levels in milk

Nanjundaswamy Ananda; Praveen V. Vadlani

2010-01-01

30

Extractability of astaxanthin in a mixed culture of a carotenoid over-producing mutant of Xanthophyllomyces dendrorhous and Bacillus circulans in two-stage batch fermentation  

Microsoft Academic Search

The productivity and extractability of astaxanthin in a mixed culture of Xanthophyllomyces dendrorhous (formerly Phaffia rhodozyma) NCHU-FS501, an astaxanthin over-producing mutant, and Bacillus circulans CCRC 11590 was evaluated in a 1.5 l fermentor using a two-stage batch fermentation technique. The first stage was for X. dendrorhous cultivation. The second stage was the mixed fermentation of the red yeast and B.

Tony J. Fang; Joh-Ming Wang

2002-01-01

31

An unusual Xanthophyllomyces strain from leaves of Eucalyptus globulus in Chile.  

PubMed

Xanthophyllomyces sp. was isolated as an epiphytic red yeast from leaves of Eucalyptus glo-bulus in Concepción, Chile. Sexual reproduction was by basidiospores produced from one or rarely two metabasidia arising from a yeast cell without preceding paedogamy. The main carotenoid pigment was astaxanthin. This isolate did not cluster with the X. dendrorhous complex (including Phaffia rhodozyma) in ITS and 26S rDNA-based phylogenetic analyses. The phylloplane may be a further habitat for Xanthophyllomyces, in addition to the well-known spring sap-flows of deciduous trees and the recently-characterised ascostromata of Cyttaria hariotii. PMID:18501574

Weber, Roland W S; Becerra, José; Silva, Mario J; Davoli, Paolo

2007-12-23

32

Dry yeast  

NSDL National Science Digital Library

Yeast is a type of eukaryotic organism that can live in a dormant state. It can be activated from its dormant state by water and sugar. The yeast uses the sugar to grow and produces carbon dioxide gas as a byproduct.

Ranveig Thattai (None;)

2005-09-27

33

Vaginal Yeast Infections  

MedlinePLUS

... HIV/AIDS Sexually transmitted infections fact sheet Vaginal yeast infections fact sheet What is a vaginal yeast ... on vaginal yeast infections What is a vaginal yeast infection? A vaginal yeast infection is irritation of ...

34

Counting Yeast.  

ERIC Educational Resources Information Center

|Describes changes to a traditional study of population in yeast colonies. Changes to the procedures include: (1) only one culture per student team; (2) cultures are inoculated only once; and (3) the same tube is sampled daily. (DDR)|

Bealer, Jonathan; Welton, Briana

1998-01-01

35

Yeast Infections  

MedlinePLUS

Candida is the scientific name for yeast. It is a fungus that lives almost everywhere, including in ... infection that causes white patches in your mouth Candida esophagitis is thrush that spreads to your esophagus, ...

36

Yeast Infection (Candidiasis)  

MedlinePLUS

newsletter | contact Share | Yeast Infection (Candidiasis) Information for adults A A A This is a candida (yeast) infection of the skin folds of the abdomen. Overview Candidiasis, commonly known as a yeast infection, is an infection with the common yeast ( ...

37

Yeast Droplets  

NASA Astrophysics Data System (ADS)

It is well known that the Young's law and surface tension govern the shape of liquid droplets on solid surfaces. Here we address through experiments and theory the shape of growing aggregates of yeast on agar substrates, and assess whether these ideas still hold. Experiments are carried out on Baker's yeast, with different levels of expressions of an adhesive protein governing cell-cell and cell-substrate adhesion. Changing either the agar concentration or the expression of this protein modifies the local contact angle of a yeast droplet. When the colony is small, the shape is a spherical cap with the contact angle obeying Young's law. However, above a critical volume this structure is unstable, and the droplet becomes nonspherical. We present a theoretical model where this instability is caused by bulk elastic effects. The model predicts that the transition depends on both volume and contact angle, in a manner quantitatively consistent with our experiments.

Nguyen, Baochi; Upadhyaya, Arpita; van Oudenaarden, Alexander; Brenner, Michael

2002-11-01

38

Yeast-Air Balloons  

NSDL National Science Digital Library

In this activity, learners make a yeast-air balloon to get a better idea of what yeast can do. Learners discover that the purpose of leaveners like yeast is to produce the gas that makes bread rise. Learners discover that as yeast feeds on sugar, it produces carbon dioxide which slowly fills the balloon.

Exploratorium, The

2012-03-10

39

A Feast for Yeast  

NSDL National Science Digital Library

In this activity on page 6 of the PDF, learners investigate yeast. Learners prepare an experiment to observe what yeast cells like to eat. Learners feed the yeast cells various ingredients in plain bread--water, flour, sugar, and salt--to discover yeast's favorite food.

Society, American C.

2000-01-01

40

Vaginal Yeast Infections (For Parents)  

MedlinePLUS

... infection is simple and painless. What Is a Yeast Infection? A yeast infection, also known as candidiasis ( ... you can be treated appropriately. Do Guys Get Yeast Infections? Guys don't get vaginal yeast infections, ...

41

Yeast Infection during Pregnancy  

MedlinePLUS

... may be reprinted for personal, noncommercial use only. Yeast infection during pregnancy: Are over-the-counter treatments ... share your e-mail address Sign up Question Yeast infection during pregnancy: Are over-the-counter treatments ...

42

Yeast Infection (Vaginal)  

MedlinePLUS

... may be reprinted for personal, noncommercial use only. Yeast infection (vaginal) By Mayo Clinic staff Original Article: http://www.mayoclinic.com/health/yeast-infection/DS01182 Definition Symptoms Causes Risk factors Preparing ...

43

Yeast Education Network  

NSDL National Science Digital Library

The Yeast Education Network provides a variety of resources to facilitate use of the budding yeast Saccharomyces cerevisiae in undergraduate science curricula. Laboratory, classroom, and computer-based activities can be used with college and advanced high school students.

44

Yeast Based Sensors  

NASA Astrophysics Data System (ADS)

Since the first microbial cell sensor was studied by Karube et al. in 1977, many types of yeast based sensors have been developed as analytical tools. Yeasts are known as facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions. The yeast based sensor consisted of a DO electrode and an immobilized omnivorous yeast. In yeast based sensor development, many kinds of yeast have been employed by applying their characteristics to adapt to the analyte. For example, Trichosporon cutaneum was used to estimate organic pollution in industrial wastewater. Yeast based sensors are suitable for online control of biochemical processes and for environmental monitoring. In this review, principles and applications of yeast based sensors are summarized.

Shimomura-Shimizu, Mifumi; Karube, Isao

45

Lager brewing yeast  

Microsoft Academic Search

Lager brewing yeast is a group of closely related strains of Saccharomyces pastorianus\\/S. carlsbergensis used for lager beer production all over the world, making it one of the most important industrial yeasts. The pure cultivation\\u000a of yeast was established in the early 1880’s with immediate practical success for lager brewing yeast. However, almost a century\\u000a would elapse before its genetics

Yukiko Kodama; Morten C. Kielland-Brandt; Jørgen Hansen

46

[Yeasts contaminating salmon roe].  

PubMed

Quantitative and species compositions of yeast contaminating eggs, fry and fingerlings of Salmo gairdneri Rich under artificial breeding have been studied. Prevalence of species of genera Candida, Rhodotorula, Cryptococcus and Debaryomyces is noted. Yeast isolated from perished eggs and sick fry do not possess pathogenic properties. Certain strains of yeast make stimulating effect on the studied microorganisms. PMID:8983527

Nagornaia, S S; Ignatova, E A; Isaeva, N M; Davydov, O N; Podgorski?, V S

47

Prions in Yeast  

PubMed Central

The concept of a prion as an infectious self-propagating protein isoform was initially proposed to explain certain mammalian diseases. It is now clear that yeast also has heritable elements transmitted via protein. Indeed, the “protein only” model of prion transmission was first proven using a yeast prion. Typically, known prions are ordered cross-? aggregates (amyloids). Recently, there has been an explosion in the number of recognized prions in yeast. Yeast continues to lead the way in understanding cellular control of prion propagation, prion structure, mechanisms of de novo prion formation, specificity of prion transmission, and the biological roles of prions. This review summarizes what has been learned from yeast prions.

Liebman, Susan W.; Chernoff, Yury O.

2012-01-01

48

Transformation of Yeast  

Microsoft Academic Search

A stable leu2- yeast strain has been transformed to LEU2+ by using a chimeric ColE1 plasmid carrying the yeast leu2 gene. We have used recently developed hybridization and restriction endonuclease mapping techniques to demonstrate directly the presence of the transforming DNA in the yeast genome and also to determine the arrangement of the sequences that were introduced. These studies show

Albert Hinnen; James B. Hicks; Gerald R. Fink

1978-01-01

49

Population Growth in Yeasts  

NSDL National Science Digital Library

This lesson is the second of two that explore cellular respiration and population growth in yeasts. In the first lesson, students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Based on questions that arose during the first lesson and its associated activity, in this lesson students work in small groups to design experiments that will determine how environmental factors affect yeast population growth.

Engineering K-Ph.d. Program

50

Nucleic Acid Amplification in Yeast.  

National Technical Information Service (NTIS)

Plasmid DNA from single yeast colonies was efficiently amplified using rolling circle amplification (RCA). The amplified DNA was directly used for restriction digestion, DNA sequencing, and yeast transformation. The RCA of plasmid DNA from single yeast co...

W. Farmerie W. Y. Song X. Ding

2004-01-01

51

Screening of a soil metatranscriptomic library by functional complementation of Saccharomyces cerevisiae mutants.  

PubMed

Metatranscriptomics applied to environmental transcripts provides unique opportunities to reveal microbial activity in the environment and to discover novel enzymes of potential use in biotechnological applications. Here, by functional complementation of a pho5(-) mutation (affecting a repressible acid phosphatase) and a his3(-) mutation in Saccharomyces cerevisiae, we identified fungal genes encoding an acid phosphatase and an imidazoleglycerol-phosphate dehydratase in a metatranscriptomic library, which was obtained by reverse-transcribed polyA fraction of total RNA extracted from the organic layer of a sugar maple forest soil, constructed in the modified yeast secretion vector pTEF-MF-SfiI A/B. Yeast transformants exhibiting phosphatase activity were identified in a colony-staining assay and transformants with his3(-)-complementing genes were detected by plating on histidine-deficient medium. In each screen one DNA insert was found and sequenced. The sequenced his3(-)-complementing gene showed strong similarity to a basidiomycete imidazoleglycerol-phosphate dehydratase (76% identity to a Phaffia rhodozyma enzyme). The candidate showing phosphatase activity was found to produce phosphatase extracellularly, the enzyme showing highest activity at pH 4 and between 40 and 50°C when 4-nitrophenyl phosphate was used as substrate. The sequenced insert showed strong similarity to a basidiomycete acid phosphatase (60% identity to Postia placenta). PMID:20869217

Kellner, Harald; Luis, Patricia; Portetelle, Daniel; Vandenbol, Micheline

2010-09-23

52

Moonlighting Proteins in Yeasts  

PubMed Central

Proteins able to participate in unrelated biological processes have been grouped under the generic name of moonlighting proteins. Work with different yeast species has uncovered a great number of moonlighting proteins and shown their importance for adequate functioning of the yeast cell. Moonlighting activities in yeasts include such diverse functions as control of gene expression, organelle assembly, and modification of the activity of metabolic pathways. In this review, we consider several well-studied moonlighting proteins in different yeast species, paying attention to the experimental approaches used to identify them and the evidence that supports their participation in the unexpected function. Usually, moonlighting activities have been uncovered unexpectedly, and up to now, no satisfactory way to predict moonlighting activities has been found. Among the well-characterized moonlighting proteins in yeasts, enzymes from the glycolytic pathway appear to be prominent. For some cases, it is shown that despite close phylogenetic relationships, moonlighting activities are not necessarily conserved among yeast species. Organisms may utilize moonlighting to add a new layer of regulation to conventional regulatory networks. The existence of this type of proteins in yeasts should be taken into account when designing mutant screens or in attempts to model or modify yeast metabolism.

Gancedo, Carlos; Flores, Carmen-Lisset

2008-01-01

53

Genetic Improvement of Baker's Yeasts  

Microsoft Academic Search

Yeasts have been used for many thousands of years to produce leavened bread. Nowadays the production of baker's yeast biomass represents a highly competitive multi-billion dollar global industry. The environmental conditions that prevail during manufacture and application of baker's yeasts, coupled with the sheer variety of bread making processes and recipes used around the world, place considerable demands on yeasts.

Paul V. Attfield; Philip J. L. Bell

2003-01-01

54

TRP channels in yeast.  

PubMed

Microbes have made numerous contributions to the study of biology and medicine. Those contributions also include many original discovery's in the study of ion channels often thought as the province of neuroscientists or cardiophysiologists. Yeast have long been used as a model organism and TRP channel genes and their transmembrane products touted as the "vanguards of the sensory system" can be identified in the genomes of many yeasts. This article aims to review the study of these TRP channels in yeast their discovery, electrophysiological properties and physiological function. PMID:21290303

Kaleta, Marta; Palmer, Christopher

2011-01-01

55

Yeast infections (image)  

MedlinePLUS

Yeast infections may follow a course of antibiotics that were prescribed for another purpose. The antibiotics change the normal "balance" between organisms in the vagina by suppressing the growth of protective bacteria that normally have an antifungal effect.

56

Mutant yeast on drugs  

Microsoft Academic Search

Analyzing drug-treated and mutant yeast cells with the new tools of genomics enables the identification of drug targets and should improve the odds of developing useful therapeutics (pages 1293–1301).

David J. Lockhart

1998-01-01

57

[Aspects of yeast biodiversity].  

PubMed

Yeast biodiversity represents a dynamic scientific domain characterized by permanent emerging theories and accumulation of new data. Identification of genome structure for a number of yeast species and elucidation of regulatory pathways for species-specific metabolic networks, lead to development of numerous applications of yeasts in industry, biotechnology, therapeutics and bioremediation. The studies of the scientific community were long time focused on Saccharomyces cerevisae due mainly to its use in food production. Therefore, the species belonging to Saccharomyces genus became reference points for genomics and biodiversity studies. During last decades there is a growing interest for yeast species able to produce biomass by assimilating or degrading various compounds such as methanol, hydrocarbons, wood hydrolisates and other residues or by-products from different industries. PMID:23745219

Csutak, Ortansa; Vassu, Tatiana

58

Yeast expression platforms  

Microsoft Academic Search

Yeasts provide attractive expression platforms. They combine ease of genetic manipulations and the option for a simple fermentation\\u000a design of a microbial organism with the capabilities of an eukaryotic organism to secrete and to modify a protein according\\u000a to a general eukaryotic scheme. For platform applications, a range of yeast species has been developed during the last decades.\\u000a We present

Erik Böer; Gerhard Steinborn; Gotthard Kunze; Gerd Gellissen

2007-01-01

59

Nitrile Metabolizing Yeasts  

NASA Astrophysics Data System (ADS)

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 enzymes of yeasts.

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

60

Oxygen requirements of yeasts.  

PubMed

Type species of 75 yeast genera were examined for their ability to grow anaerobically in complex and mineral media. To define anaerobic conditions, we added a redox indicator, resazurin, to the media to determine low redox potentials. All strains tested were capable of fermenting glucose to ethanol in oxygen-limited shake-flask cultures, even those of species generally regarded as nonfermentative. However, only 23% of the yeast species tested grew under anaerobic conditions. A comparative study with a number of selected strains revealed that Saccharomyces cerevisiae stands out as a yeast capable of rapid growth at low redox potentials. Other yeasts, such as Torulaspora delbrueckii and Candida tropicalis, grew poorly mu max, 0.03 and 0.05 h-1, respectively) under anaerobic conditions in mineral medium supplemented with Tween 80 and ergosterol. The latter organisms grew rapidly under oxygen limitation and then displayed a high rate of alcoholic fermentation. It can be concluded that these yeasts have hitherto-unidentified oxygen requirements for growth. PMID:2082825

Visser, W; Scheffers, W A; Batenburg-van der Vegte, W H; van Dijken, J P

1990-12-01

61

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

62

Virtual Yeast Cell  

NSDL National Science Digital Library

Learning about the various parts of a cell can be tricky business, but this virtual yeast cell offered by The University of Nottingham will come in handy for biology students and science instructors. This learning resource was created to help students in the brewing science program learn about yeast cytology, though just about anyone with an interest in cells will learn something from visiting the site. After entering the interactive cell, visitors can click on different parts of the cell (such as the cytoplasm or the nucleus) in order to learn more about the importance of each one. Visitors should remember that they can also download the virtual yeast cell and use it in the classroom or just with a group of friends.

2008-02-28

63

Yeast killer systems.  

PubMed Central

The killer phenomenon in yeasts has been revealed to be a multicentric model for molecular biologists, virologists, phytopathologists, epidemiologists, industrial and medical microbiologists, mycologists, and pharmacologists. The surprisingly widespread occurrence of the killer phenomenon among taxonomically unrelated microorganisms, including prokaryotic and eukaryotic pathogens, has engendered a new interest in its biological significance as well as its theoretical and practical applications. The search for therapeutic opportunities by using yeast killer systems has conceptually opened new avenues for the prevention and control of life-threatening fungal diseases through the idiotypic network that is apparently exploited by the immune system in the course of natural infections. In this review, the biology, ecology, epidemiology, therapeutics, serology, and idiotypy of yeast killer systems are discussed.

Magliani, W; Conti, S; Gerloni, M; Bertolotti, D; Polonelli, L

1997-01-01

64

Methods for yeast characterization from industrial products  

Microsoft Academic Search

This work compared the efficiency of four methods for the identification of industrial yeast strains and the establishment of a pattern for yeast characterization to be used during industrial fermentation processes, allowing the detection of yeast contaminants. Five strains of yeast currently used in the Brazilian fuel alcohol industry (about 99% of the yeast used for this purpose), and yeast

Luiz H Gomes; Keila M. R Duarte; Juan L Argueso; Sergio Echeverrigaray; Flavio C. A Tavares

2000-01-01

65

L-arabinose fermenting yeast  

DOEpatents

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##

Zhang, Min (Lakewood, CO); Singh, Arjun (Lakewood, CO); Knoshaug, Eric (Golden, CO); Franden, Mary Ann (Centennial, CO); Jarvis, Eric (Boulder, CO); Suominen, Pirkko (Maple Grove, MN)

2010-12-07

66

Conversion of pentoses by yeasts  

SciTech Connect

The utilization and conversion of D-xylose, D-xyulose, L-arabinose, and xylitol by yeast strains have been investigated with the following results: 1) The majority of yeasts tested utilize D-xylose and produce polyols, ethanol, and organic acids. The type and amount of products formed varies with the yeast strains used. The most commonly detected product is xylitol. 2) The majority of yeasts tested utilize D-xylulose aerobically and fermentatively to produce ethanol, xylitol D-arabitol, and organic acids. The type and amount of products varies depending upon the yeast strains used. 3) Xylitol is a poor carbon and energy source for most yeasts tested. Some yeast strains produce small amounts of ethanol from xylitol. 4) Most yeast strains utilize L-arabinose, and L-arabitol is the common product. Small amounts of ethanol are also produced by some yeast strains. 5) Of the four substrates examined, D-xylulose was the preferred substrate, followed by D-xylose, L-arabinose, and xylitol. 6) Mutant yeast strains that exhibit different metabolic product patterns can be induced and isolated from Candida sp. Saccharomyces cerevisiae, and other yeasts. These mutant strains can be used for ethanol production from D-xylose as well as for the study of metabolic regulation of pentose utilization in yeasts.

Gong, C.S.; Claypool, T.A.; Maun, C.M.; Mccracken, L.D.; Tsao, G.T.; Ueng, P.P.

1983-01-01

67

Yeasts from the North Sea  

Microsoft Academic Search

Yeasts were isolated from twelve established sites in the North Sea from 1964 to 1966. A percentage frequency of 99% with populations varying from 3000 viable cells\\/L was observed. This mycota was characterized by considerable spatial and temporal fluctuation, with the dominant yeast present being the ascosporogenous species, Debaryomyces hansenii. This taxon, as well as other common North Sea yeasts,

S. P. Meyers; D. G. Ahearn; W. Gunkel; F. J. Roth

1967-01-01

68

Evaluation of YeastIdent and Uni-Yeast-Tek yeast identification systems.  

PubMed Central

The accuracy of the new API YeastIdent system and the Flow Laboratories Uni-Yeast-Tek identification kit with an expanded data base was evaluated in comparison to the API 20C yeast identification system by three laboratories. A total of 489 test isolates were used, biased toward yeasts commonly encountered in clinical specimens. Isolates not in a system's data base were not counted in the evaluation of that system. For isolates in their data base, YeastIdent was 55% accurate and Uni-Yeast-Tek was 40% accurate. By the manufacturer's criteria of reliable identification without additional tests, both systems failed to identify many common and uncommon species. The limited number of substrates and difficulties in assessing results obtained with 11 of the API YeastIdent substrates and apparent errors in the expanded Uni-Yeast-Tek data base appeared to be major factors limiting the accuracy of these systems.

Salkin, I F; Land, G A; Hurd, N J; Goldson, P R; McGinnis, M R

1987-01-01

69

Genome evolution in yeasts  

Microsoft Academic Search

Identifying the mechanisms of eukaryotic genome evolution by comparative genomics is often complicated by the multiplicity of events that have taken place throughout the history of individual lineages, leaving only distorted and superimposed traces in the genome of each living organism. The hemiascomycete yeasts, with their compact genomes, similar lifestyle and distinct sexual and physiological properties, provide a unique opportunity

Bernard Dujon; David Sherman; Gilles Fischer; Pascal Durrens; Serge Casaregola; Ingrid Lafontaine; Jacky de Montigny; Christian Marck; Cécile Neuvéglise; Emmanuel Talla; Nicolas Goffard; Lionel Frangeul; Michel Aigle; Véronique Anthouard; Anna Babour; Valérie Barbe; Stéphanie Barnay; Sylvie Blanchin; Jean-Marie Beckerich; Emmanuelle Beyne; Claudine Bleykasten; Anita Boisramé; Jeanne Boyer; Laurence Cattolico; Fabrice Confanioleri; Antoine de Daruvar; Laurence Despons; Emmanuelle Fabre; Cécile Fairhead; Hélène Ferry-Dumazet; Alexis Groppi; Florence Hantraye; Christophe Hennequin; Nicolas Jauniaux; Philippe Joyet; Rym Kachouri; Alix Kerrest; Romain Koszul; Marc Lemaire; Isabelle Lesur; Laurence Ma; Héloïse Muller; Jean-Marc Nicaud; Macha Nikolski; Sophie Oztas; Odile Ozier-Kalogeropoulos; Stefan Pellenz; Serge Potier; Guy-Franck Richard; Marie-Laure Straub; Audrey Suleau; Dominique Swennen; Fredj Tekaia; Micheline Wésolowski-Louvel; Eric Westhof; Bénédicte Wirth; Maria Zeniou-Meyer; Ivan Zivanovic; Monique Bolotin-Fukuhara; Agnès Thierry; Christiane Bouchier; Bernard Caudron; Claude Scarpelli; Claude Gaillardin; Jean Weissenbach; Patrick Wincker; Jean-Luc Souciet

2004-01-01

70

Biosynthesis of yeast mitochondria  

Microsoft Academic Search

Ethidium bromide selectively inhibits growth of the petite negative yeast Kluyveromyces fragilis on a non-fermentable carbon source. In short term experiments, when growth in ethidium is continued for about 11 generations, this inhibition is accompanied by a loss of cyanide sensitive respiration and particulate cytochromes, an initial phase of microcolony production, and an inhibition of mitochondrial DNA synthesis. The loss

A. A. Luha; P. A. Whittaker; R. C. Hammond

1974-01-01

71

Yeast DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from yeast using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Hays, Lana

2009-01-01

72

L-arabinose fermenting yeast  

DOEpatents

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.

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

2013-02-12

73

Mammalian Homology to Yeast  

NSDL National Science Digital Library

This site allows researchers to retrieve a yeast-against-mammal Basic Local Alignment Search Tool (BLAST) report by entering a gene or ORF name into a search function. The supporting data were first summarized in a recent Science article which is provided via a link to the journal (Science, 22 July 1997; Issue 277: p.1259). Steve Chervitz of Stanford University maintains this site.

1997-01-01

74

''Is Yeast Alive?''  

NSDL National Science Digital Library

In this inquiry activity students explore the characteristics of living organisms to determine whether yeast meets the criteria of a living thing. This inquiry activity was developed by a K-12 science teacher in the American Physiological SocietyÃÂs 2006 Frontiers in Physiology Program. The NSES Standards addressed by this activity are current as of the year of development. For more information on the Frontiers in Physiology Program, please visit www.frontiersinphys.org.

Ms. Katrenia Hosea-Flanigan (Frank Cody High School)

2006-04-01

75

Chemical transformation of yeast.  

PubMed

Transformation of chemically competent yeast cells is a method for introducing exogenous DNA into living cells. Typically, the DNA is either a plasmid carrying an autonomous replication sequence that allows for propagation or a linear piece of DNA to be integrated into the genome. The DNA usually also carries a marker that allows for selection of successfully transformed cells by plating on the appropriate selective media. PMID:24011057

Bergkessel, Megan; Guthrie, Christine

2013-01-01

76

Glutathione Production in Yeast  

NASA Astrophysics Data System (ADS)

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

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

77

Conservation of yeasts by dehydration  

Microsoft Academic Search

The presented material concerns the theoretical basis for obtaining high-quality active dry biopreparations. It deals with the present understanding of anabiosis, contains data on yeast resistance against dehydration and the limits for preserving the viability of microorganisms in anabiosis. The process of water transport in yeast biomass during dehydration is discussed.\\u000a The changes and transformations in yeast cells occuring after

Martin Beker; Alexander Rapoport

78

Yeast interactions and wine flavour.  

PubMed

Wine is the product of complex interactions between fungi, yeasts and bacteria that commence in the vineyard and continue throughout the fermentation process until packaging. Although grape cultivar and cultivation provide the foundations of wine flavour, microorganisms, especially yeasts, impact on the subtlety and individuality of the flavour response. Consequently, it is important to identify and understand the ecological interactions that occur between the different microbial groups, species and strains. These interactions encompass yeast-yeast, yeast-filamentous fungi and yeast-bacteria responses. The surface of healthy grapes has a predominance of Aureobasidium pullulans, Metschnikowia, Hanseniaspora (Kloeckera), Cryptococcus and Rhodotorula species depending on stage of maturity. This microflora moderates the growth of spoilage and mycotoxigenic fungi on grapes, the species and strains of yeasts that contribute to alcoholic fermentation, and the bacteria that contribute to malolactic fermentation. Damaged grapes have increased populations of lactic and acetic acid bacteria that impact on yeasts during alcoholic fermentation. Alcoholic fermentation is characterised by the successional growth of various yeast species and strains, where yeast-yeast interactions determine the ecology. Through yeast-bacterial interactions, this ecology can determine progression of the malolactic fermentation, and potential growth of spoilage bacteria in the final product. The mechanisms by which one species/strain impacts on another in grape-wine ecosystems include: production of lytic enzymes, ethanol, sulphur dioxide and killer toxin/bacteriocin like peptides; nutrient depletion including removal of oxygen, and production of carbon dioxide; and release of cell autolytic components. Cell-cell communication through quorum sensing molecules needs investigation. PMID:12892919

Fleet, Graham H

2003-09-01

79

Production of food yeast from starchy substrates  

Microsoft Academic Search

Fifteen yeast strains were selected for the production of food yeast from starchy substrates. From comparison with the amylolytic yeasts, a strain of Schwanniomyces castellii was selected and its characteristics are described.

A. Touzi; J. P. Prebois; G. Moulin; F. Deschamps; P. Galzy

1982-01-01

80

21 CFR 172.896 - Dried yeasts.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Dried yeasts. 172.896 Section 172.896 Food and Drugs...CONSUMPTION Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces...

2009-04-01

81

21 CFR 172.896 - Dried yeasts.  

Code of Federal Regulations, 2010 CFR

...3 2010-01-01 2009-04-01 true Dried yeasts. 172.896 Section 172.896 Food and Drugs...CONSUMPTION Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces...

2010-01-01

82

21 CFR 172.896 - Dried yeasts.  

Code of Federal Regulations, 2013 CFR

...FOOD FOR HUMAN CONSUMPTION 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...

2013-04-01

83

Thirteen-week oral toxicity study of carotenoid pigment from Rhodotorula glutinis DFR-PDY in rats.  

PubMed

Carotenoids from some of the coloured yeasts like Rhodotorula, Phaffia rhodozyma have attracted commercial interest as a natural pigment for foods. Red yeast isolated from contaminated Potato dextrose agar plate (PDA), designated as Rhodotorula glutinis DFR-PDY has been found to produce carotenoids. In the present study toxicological evaluation of carotenoid pigment has been reported. Experiment was conducted on 3 groups of albino rats. One group with vehicle control (palm oil) and 2 groups with two different doses of red yeast pigment (lower and higher dose) were fed to rats (both male and female) by gavages for 13 weeks. Gain in body weight of rats and food consumption were monitored at regular intervals. Hematological studies revealed that there is no much difference in erythrocytes, packed cell volume, Mean corpuscular volume (MCV), Mean corpuscular haemoglobin concentration (MCHC), platelets and differential counts. Total leucocyte count (TLC) is less in case of higher dose group than the lower and control groups. Whereas, hemoglobin is more in case of higher dose than the lower dose group and least in control group. Even clinico-chemical parameters and urine analysis of vehicle control group and pigment fed rats revealed that there were no major differences between them as well as between two different genders of rats and also interaction between different doses and the genders. Histopathology of these experimental animals revealed that there are no major histological changes found between the groups. It may be concluded that the whole pigment extract from R. glutinis DFR-PDY may be used safely in food preparations as food colourant with an added benefit of antioxidant activity. PMID:23140023

Latha, B V; Jeevaratanm, K

2012-09-01

84

Yeasts: From genetics to biotechnology  

Microsoft Academic Search

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

S. Russo; G. Poli; R. B. Siman-Tov

1995-01-01

85

A numericlature of the Yeasts  

Microsoft Academic Search

A numericlature, based on a descriptive numerical code has been compiled for the yeasts. A total of 429 yeast species are represented by 388 unique four-, six- or seven-digit numbers and of these 364 correspond to single species. It is suggested that the coding method is a valid alternative to binomial nomenclature based on a conventional hierarchical classification. It can

A. J. Griffiths

1981-01-01

86

Growth of Solar Radiated Yeast.  

National Technical Information Service (NTIS)

This researcher plans to determine if solar radiation affects the growth of yeast. The irradiated yeast was obtained from a sample exposed in space during a Space Shuttle flight of September 9-20, 1994. Further, the control groups were held at: (1) Goddar...

T. Kraft

1995-01-01

87

The intronome of budding yeasts  

Microsoft Academic Search

Whatever their abundance in genomes, spliceosomal introns are the signature of eukaryotic genes. The sequence of Saccharomyces cerevisiae, achieved fifteen years ago, revealed that this yeast has very few introns, but conserved intron boundaries typical for an intron definition mechanism. With the improvement and the development of new sequencing technologies, yeast genomes have been extensively sequenced during the last decade. We

Cécile Neuvéglise; Christian Marck; Claude Gaillardin

2011-01-01

88

Apoptotic death of ageing yeast  

Microsoft Academic Search

Yeast has been a valuable model to study replicative and chronological ageing processes. Replicative ageing is defined by the number of daughter cells a mother can give birth to and hence reflects the ageing situation in proliferating cells, whereas chronological ageing is widely accepted as a model for postmitotic tissue ageing. Since both ageing forms end in yeast programmed death

Patrick Rockenfeller; Frank Madeo

2008-01-01

89

The Budding Yeast Nucleus  

PubMed Central

The budding yeast nucleus, like those of other eukaryotic species, is highly organized with respect to both chromosomal sequences and enzymatic activities. At the nuclear periphery interactions of nuclear pores with chromatin, mRNA, and transport factors promote efficient gene expression, whereas centromeres, telomeres, and silent chromatin are clustered and anchored away from pores. Internal nuclear organization appears to be function-dependent, reflecting localized sites for tRNA transcription, rDNA transcription, ribosome assembly, and DNA repair. Recent advances have identified new proteins involved in the positioning of chromatin and have allowed testing of the functional role of higher-order chromatin organization. The unequal distribution of silent information regulatory factors and histone modifying enzymes, which arises in part from the juxtaposition of telomeric repeats, has been shown to influence chromatin-mediated transcriptional repression. Other localization events suppress unwanted recombination. These findings highlight the contribution budding yeast genetics and cytology have made to dissecting the functional role of nuclear structure.

Taddei, Angela; Schober, Heiko; Gasser, Susan M.

2010-01-01

90

Stress signaling in yeast.  

PubMed

In the yeast Saccharomyces cerevisiae three positive transcriptional control elements are activated by stress conditions: heat shock elements (HSEs), stress response elements (STREs) and AP-1 responsive elements (AREs). HSEs bind heat shock transcription factor (HSF), which is activated by stress conditions causing accumulation of abnormal proteins. STREs mediate transcriptional activation by multiple stress conditions. They are controlled by high osmolarity via the HOG signal pathway, which comprises a MAP kinase module and a two-component system homologous to prokaryotic signal transducers. AREs bind the transcription factor Yap1p. The three types of control elements seem to have overlapping, but distinct functions. Some stress proteins encoded by HSE-regulated genes are necessary for growth of yeast under moderate stress, products of STRE-activated genes appear to be important for survival under severe stress and ARE-controlled genes may mainly function during oxidative stress and in the response to toxic conditions, such as caused by heavy metal ions. PMID:8526890

Ruis, H; Schüller, C

1995-11-01

91

Yeasts: From genetics to biotechnology  

SciTech Connect

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 {open_quotes}biotechnological revolution{close_quotes} by virtue of both their features and their very long and safe use in human nutrition and industry. 175 refs., 4 figs., 6 tabs.

Russo, S.; Poli, G. [Univ. of Milan (Italy); Siman-Tov, R.B. [Univ. of Jerusalem, Rehovot (Israel)

1995-12-31

92

Yeasts from the leaves of pasture plants  

Microsoft Academic Search

The yeast population upon the leaves of pasture plants in New Zealand has been investigated in relation to season, soil yeast flora, and incidence of facial eczema toxin in autumn pasture. Leaf yeasts were shown to be taxonomically distinct from soil yeasts and to vary with season but not to vary with the localities sampled. During most of the year

M. E. di Menna

1959-01-01

93

Effects of Yeast Freezing in Frozen Dough  

Microsoft Academic Search

Cereal Chem. 80(4):454-458 The effects of freezing and frozen storage of bread dough and com- pressed yeast on bread quality were studied. Besides, the effects of compressed yeast freezing on cell viability, gas production and release of substances by the yeast cells were examined. Freezing and frozen storage of dough made with fresh yeast had more negative effects on baking

Pablo D. Ribotta; Alberto E. León; María Cristina Añón

2003-01-01

94

Yeasts in an industrial malting ecosystem  

Microsoft Academic Search

The malting ecosystem consists of two components: the germinating cereal grains and the complex microbial community. Yeasts and yeast-like fungi are an important part of this ecosystem, but the composition and the effects of this microbial group have been largely unknown. In this study we surveyed the development of yeasts and yeast-like fungi in four industrial scale malting processes. A

A. Laitila; A. Wilhelmson; E. Kotaviita; J. Olkku; S. Home; R. Juvonen

2006-01-01

95

A numericlature of the yeasts.  

PubMed

A numericlature, based on a descriptive numerical code has been compiled for the yeasts. A total of 429 yeast species are represented by 389 unique four-, six- or seven-digit numbers and of these 364 correspond to single species. It is suggested that the coding method is a valid alternative to binomial nomenclature based on a conventional hierarchical classification. It can serve as a simple reference system and can be used practically as a means of differentiating between large numbers of new isolates of yeasts. PMID:7337435

Griffiths, A J

1981-01-01

96

Development of baking yeast from Nigerian palm-wine yeasts  

Microsoft Academic Search

Two local strains of Saccharomyces cerevisiae, Nk, and Nk2, showed leavening activities of 103% and 102% of that of a commercial yeast strain on wheat flour and of 114% and 113% on composite dough with 40% (w\\/v) maize substitution. Yeast fusion products Nk\\/Ng, Nk\\/Nk1 and Nk\\/Nk2 showed activities of 104% to 113% on wheat flour and 111% to 131% on

A. O. Ejiofor; N. Okafor; E. N. Ugwueze

1994-01-01

97

Thermostability of yeast hexokinase and yeast glucose-6-phosphate dehydrogenase  

Microsoft Academic Search

Kinetic study of the mechanism of the temperature-induced loss of the catalytic activity by yeast hexokinase (HK) and yeast\\u000a glucose-6phosphate dehydrogenase (G-6-PDG) has shown the dissociative nature of the processes. In the temperature range 40–47°C,\\u000a they are satisfactorily described in terms of consecutive reactions in which steps of irreversible denaturation of the monomeric\\u000a units follow the reversible dissociation of inactive

E. A. Zaitzeva; E. S. Chukria; O. M. Poltorak

1996-01-01

98

Yeast rises to the occasion  

PubMed Central

Genetic analyses of 15 species of yeast have shed new light on the divergence of gene regulation during evolution, with significant changes occurring after an event in which a whole genome was duplicated.

2013-01-01

99

Molecular Genetic Analysis in Yeast  

NSDL National Science Digital Library

The four exercises presented here use basic and advanced procedures of recombinant DNA technology to perform molecular genetic analysis in the yeast Saccharomyces cerevisiae. Their fulluse is intended for a senior-level molecular genetics (or similar) course; however, Experiments 1, 2, and 4 are appropriate for lower-level courses. It is expected that the instructor will have some familiarity with the concepts and terminology of recombinant DNA technology and with yeast genetics.

Daniel D. Burke (Seton Hall University;)

1989-06-06

100

Yeast Pathogens of Domestic Animals  

Microsoft Academic Search

\\u000a Mycoses of domestic animals caused by yeasts have been recorded for approximately 150 years. The majority of these infections\\u000a are cutaneous and superficial and are of minor clinical significance but fatal systemic infections are also reported. Currently,\\u000a most common pathogenic yeasts of domestic animals are included in the genera Candida, Cryptococcus and Malassezia and they are reviewed in depth in

F. J. Cabanes

101

Biotechnological Applications of Dimorphic Yeasts  

Microsoft Academic Search

The dimorphic yeasts have the equilibrium between spherical growth (budding) and polarized (hyphal or pseudohyphal tip elongation)\\u000a which can be triggered by change in the environmental conditions. The reversible growth phenomenon has made dimorphic yeasts\\u000a as an useful model to understand fungal evolution and fungal differentiation, in general. In nature dimorphism is clearly\\u000a evident in plant and animal fungal pathogens,

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

2009-01-01

102

Yeasts preservation: alternatives for lyophilisation.  

PubMed

The aim of the study was to compare the effect of two low-cost, low technology traditional methods for drying starter cultures with standard lyophilisation. Lyophilised yeast cultures and yeast cultures preserved in dry rice cakes and dry plant fibre strands were examined for viable cell counts during 6 months storage at 4 and 25 °C. None of the yeast cultures showed a significant loss in viable cell count during 6 months of storage at 4 °C upon lyophilisation and preservation in dry rice cakes. During storage at 25 °C in the dark, yeast cultures preserved in dry rice cakes, and lyophilised cultures of Saccharomyces cerevisiae and Issatchenkia orientalis showed no significant loss of viable cells up to 4 months of storage. Yeast cultures preserved in dry plant fibre strands had the greatest loss of viable count during the 6 months of storage at 25 °C. Preservation of yeasts cultures in dry rice cakes provided better survival during storage at 4 °C than lyophilisation. The current study demonstrated that traditional methods can be useful and effective for starter culture preservation in small-scale, low-tech applications. PMID:22806747

Nyanga, Loveness K; Nout, Martinus J R; Smid, Eddy J; Boekhout, Teun; Zwietering, Marcel H

2012-07-07

103

Study of amyloids using yeast  

PubMed Central

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

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

2012-01-01

104

Riboneogenesis in yeast  

PubMed Central

Summary Gluconeogenesis converts three carbon units into glucose. Here we identify an analogous pathway in Saccharomyces cerevisiae for converting three carbon units into ribose, a component of nucleic acids and nucleotides. This riboneogenic pathway involves the enzyme sedoheptulose-1,7-bisphosphatase (SHB17), whose activity was identified based on accumulation of sedoheptulose-1,7-bisphosphate in the corresponding knockout strain. We determined the crystal structure of Shb17 in complex with sedoheptulose-1,7-bisphosphate, and found that the sugar is bound in the closed furan form in the active site. Like fructose-1,6-bisphosphate, sedoheptulose-1,7-bisphosphate is produced by aldolase, in this case from erythrose 4-phosphate and dihydroxyacetone phosphate. Hydrolysis of sedoheptulose-1,7-bisphosphate by SHB17 provides an energetically favorable input to the non-oxidative pentose phosphate pathway to drive ribose production. Flux through SHB17 is enhanced under conditions when ribose demand is high relative to demand for NADPH, including during ribosome biogenesis in metabolically synchronized yeast cells. Thus, riboneogenesis provides a thermodynamically-driven route of ribose production uncoupled from formation of NADPH.

Clasquin, Michelle F.; Melamud, Eugene; Singer, Alexander; Gooding, Jessica R.; Xu, Xiaohui; Dong, Aiping; Cui, Hong; Campagna, Shawn R.; Savchenko, Alexei; Yakunin, Alexander F.; Rabinowitz, Joshua D.; Caudy, Amy A.

2011-01-01

105

Cdc42 Oscillations in Yeasts  

NSDL National Science Digital Library

A fundamental problem in cell biology is how cells define one or several discrete sites of polarity. Through mechanisms involving positive and negative feedback, the small Rho-family guanosine triphosphatase Cdc42 breaks symmetry in round budding yeast cells to define a single site of polarized cell growth. However, it is not clear how cells can define multiple sites of polarization concurrently. We discuss a study in which rod-shaped fission yeast cells, which naturally polarize growth at their two cell ends, exhibited oscillations of Cdc42 activity between these sites. We compare these findings with similar oscillatory behavior of Cdc42 detected in budding yeast cells and discuss the possible mechanism and functional outputs of these oscillations.

Felipe O. Bendezu (Switzerland;University of Lausanne REV); Sophie G. Martin (Switzerland;University of Lausanne REV)

2012-12-04

106

Candida zeylanoides: another opportunistic yeast.  

PubMed

A patient with a long history of scleroderma and gastrointestinal malabsorption requiring total parenteral nutrition was admitted with Candida zeylanoides fungemia. The yeast responded to therapy, but on two subsequent admissions for episodes of fever the blood cultures yielded the same yeast. The identity of the Candida species was established biochemically by both the API (Analytab) and Vitek system approaches. C. zeylanoides ATCC 20356 and ATCC 7351 served as controls for these analyses and for antifungal susceptibility studies and restriction endonuclease analyses of chromosomal DNA. These investigations indicated that representative isolates of the yeasts from the three episodes were identical and differed in several respects from the ATCC strains, which did not share many of the characteristics bands with the DNA restriction fragment analysis. C. zeylanoides variants capable of tolerating 35 degrees C can complicate the recovery of patients, especially individuals compromised by their underlying disease. PMID:1684799

Levenson, D; Pfaller, M A; Smith, M A; Hollis, R; Gerarden, T; Tucci, C B; Isenberg, H D

1991-08-01

107

Candida zeylanoides: another opportunistic yeast.  

PubMed Central

A patient with a long history of scleroderma and gastrointestinal malabsorption requiring total parenteral nutrition was admitted with Candida zeylanoides fungemia. The yeast responded to therapy, but on two subsequent admissions for episodes of fever the blood cultures yielded the same yeast. The identity of the Candida species was established biochemically by both the API (Analytab) and Vitek system approaches. C. zeylanoides ATCC 20356 and ATCC 7351 served as controls for these analyses and for antifungal susceptibility studies and restriction endonuclease analyses of chromosomal DNA. These investigations indicated that representative isolates of the yeasts from the three episodes were identical and differed in several respects from the ATCC strains, which did not share many of the characteristics bands with the DNA restriction fragment analysis. C. zeylanoides variants capable of tolerating 35 degrees C can complicate the recovery of patients, especially individuals compromised by their underlying disease. Images

Levenson, D; Pfaller, M A; Smith, M A; Hollis, R; Gerarden, T; Tucci, C B; Isenberg, H D

1991-01-01

108

Construction and Characterization of Cellulolytic Yeasts,  

National Technical Information Service (NTIS)

The yeast Saccharomyces cerevisiae is used in many biotechnical processes where plant raw material is utilized. However, S. cerevisiae cannot hydrolyse cellulose, the major renewable resource on earth. The successful construction of cellulolytic yeast str...

M. Penttilae

1987-01-01

109

Yeast Can Affect Behavior and Learning.  

ERIC Educational Resources Information Center

|A pediatrician recounts his experiences in diagnosing and treating allergies to common yeast germs that may result in behavior and learning problems. He lists characteristics that may predispose children to yeast-connected health problems. (CL)|

Crook, William G.

1984-01-01

110

Effect of yeast growth conditions on yeast-mycelial transition in Candida albicans  

Microsoft Academic Search

When grown and induced to form germ tubes in liquid defined media, yeast cells of Candida albicans must reach stationary phase before acquiring ability to carry out the yeast-mycelial transition. This study examined the effect of the carbon source utilized for yeast growth on the inducibility of stationary phase yeast. When grown to the same stationary phase cell density as

William M. Bell; W. LaJean Chaffin

1983-01-01

111

Chromatin and Transcription in Yeast  

PubMed Central

Understanding the mechanisms by which chromatin structure controls eukaryotic transcription has been an intense area of investigation for the past 25 years. Many of the key discoveries that created the foundation for this field came from studies of Saccharomyces cerevisiae, including the discovery of the role of chromatin in transcriptional silencing, as well as the discovery of chromatin-remodeling factors and histone modification activities. Since that time, studies in yeast have continued to contribute in leading ways. This review article summarizes the large body of yeast studies in this field.

Rando, Oliver J.; Winston, Fred

2012-01-01

112

Oily yeasts as oleaginous cell factories  

Microsoft Academic Search

Oily yeasts have been described to be able to accumulate lipids up to 20% of their cellular dry weight. These yeasts represent\\u000a a minor proportion of the total yeast population, and only 5% of them have been reported as able to accumulate more than 25%\\u000a of lipids. The oily yeast genera include Yarrowia, Candida, Rhodotorula, Rhodosporidium, Cryptococcus, Trichosporon, and Lipomyces.

Jose Manuel Ageitos; Juan Andres Vallejo; Patricia Veiga-Crespo; Tomas G. Villa

2011-01-01

113

Phylogenetics of Saccharomycetales, the ascomycete yeasts  

Microsoft Academic Search

Ascomycete yeasts (phylum Ascomycota: subphylum Saccharomycotina: class Saccharomycetes: order Saccharomycetales) comprise a monophyletic lineage with a single order of about 1000 known species. These yeasts live as saprobes, often in association with plants, animals and their interfaces. A few species account for most human mycotic infections, and fewer than 10 species are plant pathogens. Yeasts are responsible for important industrial

Sung-Oui Suh; Meredith Blackwell; Cletus P. Kurtzman; M.-A. Lachance

2006-01-01

114

Temperature abuse initiating yeast growth in yoghurt  

Microsoft Academic Search

The occurrence of yeasts in dairy products is significant because they can cause spoilage, effect desirable biochemical changes and they may adversely affect public health. While fermentative and spoilage activities of yeasts at elevated temperatures are well known in many food and beverage commodities, little attention has been given to the specific occurrence and significance of yeasts in dairy products

Bennie C. Viljoen; Analie Lourens-Hattingh; Bridget Ikalafeng; Gabor Peter

2003-01-01

115

Genetically modified industrial yeast ready for application  

Microsoft Academic Search

Tremendous progress in the genetic engineering of yeast had been achieved at the end of 20th century, including the complete genome sequence, genome-wide gene expression profiling, and whole gene disruption strains. Nevertheless, genetically modified (GM) baking, brewing, wine, and sake yeasts have not, as yet, been used commercially, although numerous industrial recombinant yeasts have been constructed. The recent progress of

Rinji Akada

2002-01-01

116

Yeast: A Research Organism for Teaching Genetics.  

ERIC Educational Resources Information Center

|Explains why laboratory strains of bakers yeast, Saccharomyces cerevisiae, are particularly suited for classroom science activities. Describes the sexual life cycle of yeast and the genetic system with visible mutations. Presents an overview of activities that can be done with yeast and gives a source for teachers to obtain more information. (PR)|

Manney, Thomas R.; Manney, Monta L.

1992-01-01

117

Enological functions of parietal yeast mannoproteins  

Microsoft Academic Search

Parietal yeast mannoproteins play a very important role in the overall vinification process. Their production and release, both during winemaking and aging on lees, depends on the specific yeast strain and the nutritional conditions. The following enological functions of parietal yeast mannoproteins have been described: (a) adsorption of ochratoxin A; (b) combination with phenolic compounds; (c) increased growth of malolactic

Andrea Caridi

2006-01-01

118

Amyloids and yeast prion biology.  

PubMed

The prions (infectious proteins) of Saccharomyces cerevisiae are proteins acting as genes, by templating their conformation from one molecule to another in analogy to DNA templating its sequence. Most yeast prions are amyloid forms of normally soluble proteins, and a single protein sequence can have any of several self-propagating forms (called prion strains or variants), analogous to the different possible alleles of a DNA gene. A central issue in prion biology is the structural basis of this conformational templating process. The in-register parallel ? sheet structure found for several infectious yeast prion amyloids naturally suggests an explanation for this conformational templating. While most prions are plainly diseases, the [Het-s] prion of Podospora anserina may be a functional amyloid, with important structural implications. Yeast prions are important models for human amyloid diseases in general, particularly because new evidence is showing infectious aspects of several human amyloidoses not previously classified as prions. We also review studies of the roles of chaperones, aggregate-collecting proteins, and other cellular components using yeast that have led the way in improving the understanding of similar processes that must be operating in many human amyloidoses. PMID:23379365

Wickner, Reed B; Edskes, Herman K; Bateman, David A; Kelly, Amy C; Gorkovskiy, Anton; Dayani, Yaron; Zhou, Albert

2013-02-12

119

Molecular Genetic Analysis in Yeast  

NSDL National Science Digital Library

This resource provides techniques and protocols used in basic and advanced procedures of recombinant DNA technology to perform molecular genetic analysis in the yeast Saccharomyces cerevisiae. Students will be exposed to techniques such as transformation, restriction endonuclease digestion, electrophoresis and Southern blot analysis.

Daniel D. Burke (Seton Hall University;)

1990-01-01

120

Optical micromanipulations inside yeast cells  

Microsoft Academic Search

We present a combination of nonlinear microscopy and optical trapping applied to three-dimensional imaging and manipulation of intracellular structures in living cells. We use Titanium-sapphire laser pulses for nonlinear microscopy of the nuclear envelope and the microtubules marked with green fluorescent protein in fission yeast. The same laser source is also used to trap small lipid granules naturally present in

Leonardo Sacconi; Iva M. Tolic-Nørrelykke; Chiara Stringari; Renzo Antolini; Francesco S. Pavone

2005-01-01

121

Telomere functions: lessons from yeast  

Microsoft Academic Search

Telomeres are specialized DNA protein structures that form the ends of eukaryotic chromosomes. In yeast, loss of even a single telomere causes a prolonged, but transitory, cell-cycle arrest. During this arrest, many broken chromosomes acquire a new telomere by one of three pathways, although at the cost of a partial loss of heterozygosity. In addition, a substantial fraction of the

Virginia A. Zakian

1996-01-01

122

TDP-43 toxicity in yeast  

PubMed Central

The budding yeast Saccharomyces cerevisiae is an emerging tool for investigating the molecular pathways that underpin several human neurodegenerative disorders associated with protein misfolding. Amyotrophic lateral sclerosis (ALS) is a devastating adult onset neurodegenerative disease primarily affecting motor neurons. The protein TDP-43 has recently been demonstrated to play an important role in the disease, however the mechanisms by which TDP-43 contributes to pathogenesis are unclear. To explore the mechanistic details that result in aberrant accumulation of TDP-43 and to discover potential strategies for therapeutic intervention, we employed a yeast TDP-43 proteinopathy model system. These studies allowed us to determine the regions of TDP-43 required for aggregation and toxicity and to define the effects of ALS-linked mutant forms of TDP-43. We have also been able to harness the power of yeast genetics to identify potent modifiers of TDP-43 toxicity using high-throughput yeast genetic screens. Here, we describe the methods and approaches that we have used in order to gain insight into TDP-43 biology and its role in disease. These approaches are readily adaptable to other neurodegenerative disease proteins.

Armakola, Maria; Hart, Michael P.; Gitler, Aaron D.

2010-01-01

123

Yeast sphingolipids: metabolism and biology  

Microsoft Academic Search

Sphingolipids have recently emerged as important bioactive molecules in addition to being critical structural components of cellular membranes. These molecules have been implicated in regulating cell growth, differentiation, angiogenesis, apoptosis, and senescene. To study sphingolipid mediated biology, it is necessary to investigate sphingolipid metabolism and its regulation. The yeast Saccharomyces cerevisiae has allowed such studies to take place as the

Lina M Obeid; Yasuo Okamoto; Cungui Mao

2002-01-01

124

Barcoding the Yeasts – Which Genes?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Old style yeast identification, as many know, is an onerous process requiring determination of growth reactions on 60-100 different media. Once completed, there is still a high degree of uncertainty about species identity. With the determination of sequences for domains 1 and 2 (D1/D2) of the nucl...

125

Observations on the Yeast Lipomyces  

Microsoft Academic Search

IN 1946, Starkey1 isolated and described a soil yeast characterized by a peculiar method of spore formation after a relatively long period of growth on solid medium. Large, round vegetative cells containing fat globules gave rise to irregularly shaped protuberances in which were afterwards formed 4-16 or more lightly pigmented spores. Lodder and Kregervan Rij2 considered these spores to be

Catherine Roberts

1957-01-01

126

Genetically modified industrial yeast ready for application.  

PubMed

Tremendous progress in the genetic engineering of yeast had been achieved at the end of 20th century, including the complete genome sequence, genome-wide gene expression profiling, and whole gene disruption strains. Nevertheless, genetically modified (GM) baking, brewing, wine, and sake yeasts have not, as yet, been used commercially, although numerous industrial recombinant yeasts have been constructed. The recent progress of genetic engineering for the construction of GM yeast is reviewed and possible requirements for their application are discussed. 'Self-cloning' yeast will be the most likely candidate for the first commercial application of GM microorganisms in food and beverage industries. PMID:16233347

Akada, Rinji

2002-01-01

127

Occurrence and Growth of Yeasts in Yogurts  

PubMed Central

Yogurts purchased from retail outlets were examined for the presence of yeasts by being plated onto oxytetracycline malt extract agar. Of the 128 samples examined, 45% exhibited yeast counts above 103 cells per g. A total of 73 yeast strains were isolated and identified as belonging to the genera Torulopsis, Kluyveromyces, Saccharomyces, Candida, Rhodotorula, Pichia, Debaryomyces, and Sporobolomyces. Torulopsis candida and Kluyveromyces fragilis were the most frequently isolated species, followed by Saccharomyces cerevisiae, Rhodotorula rubra, Kluyveromyces lactis, and Torulopsis versatilis. The growth of yeasts in yogurts was related to the ability of the yeasts to grow at refrigeration temperatures, to ferment lactose and sucrose, and to hydrolyze milk casein. Most yeast isolates grew in the presence of 100 ?g of sorbate and benzoate preservatives per ml. Higher yeast counts from yogurts were obtained when the yogurts were plated onto oxytetracycline malt extract agar than when they were plated onto acidified malt extract agar.

Suriyarachchi, V. R.; Fleet, G. H.

1981-01-01

128

Protein selection using yeast surface display.  

PubMed

Binding proteins are typically isolated from combinatorial libraries of scaffold proteins using one of the many library screening tools available, such as phage display, yeast surface display or mRNA display. A key principle underlying these screening technologies is the establishment of a link between each unique mutant protein and its corresponding genetic code. The mutant proteins binding a desired target species are separated and subsequently identified using the genetic code. In this review, we largely focus on the use of yeast surface display for the isolation of binding proteins from combinatorial libraries. In yeast surface display, the yeast cell links the mutant protein to its coding DNA. Each yeast cell expresses the mutant proteins as fusions to a yeast cell wall protein; the yeast cell also carries plasmid DNA that codes for the mutant protein. Over the years, the yeast surface display platform has emerged as a powerful tool for protein engineering, and has been used in a variety of applications including affinity maturation, epitope mapping and biophysical characterization of proteins. Here we present a broad overview of the yeast surface display system and its applications, and compare it with other contemporary screening platforms. Further, we present detailed protocols for the use of yeast surface display to isolate de novo binding proteins from combinatorial libraries, and subsequent biophysical characterization of binders. These protocols can also be easily modified for affinity maturation of the isolated de novo binders. PMID:22465794

Gera, Nimish; Hussain, Mahmud; Rao, Balaji M

2012-03-23

129

Transformation systems of non-Saccharomyces yeasts.  

PubMed

This review describes the transformation systems including vectors, replicons, genetic markers, transformation methods, vector stability, and copy numbers of 13 genera and 31 species of non-Saccharomyces yeasts. Schizosaccharomyces pombe was the first non-Saccharomyces yeast studied for transformation and genetics. The replicons of non-Saccharomyces yeast vectors are from native plasmids, chromosomal DNA, and mitochondrial DNA of Saccharomyces cerevisiae, non-Saccharomyces yeasts, protozoan, plant, and animal. Vectors such as YAC, YCp, YEp, YIp, and YRp were developed for non-Saccharomyces yeasts. Forty-two types of genes from bacteria, yeasts, fungi, and plant were used as genetic markers that could be classified into biosynthetic, dominant, and colored groups to construct non-Saccharomyces yeasts vectors. The LEU2 gene and G418 resistance gene are the two most popular markers used in the yeast transformation. All known transformation methods such as spheroplast-mediating method, alkaline ion treatment method, electroporation, trans-kingdom conjugation, and biolistics have been developed successfully for non-Saccharomyces yeasts, among which the first three are most widely used. The highest copy number detected from non-Saccharomyces yeasts is 60 copies in Kluyveromyces lactis. No general rule is known to illustrate the transformation efficiency, vector stability, and copy number, although factors such as vector composition, host strain, transformation method, and selective pressure might influence them. PMID:11599715

Wang, T T; Choi, Y J; Lee, B H

2001-01-01

130

Oxidative stress responses in yeast  

Microsoft Academic Search

Yeast, and especially S. cerevisiae, is a unique eukaryotic model organism for studying oxidative stress and its cellular responses. S. cerevisiae has become a very powerful tool to decipher the complexity of these biologically important responses, because it offers the\\u000a relative simplicity of a single celled eukaryotic organism that enables the combination and integration of genetic, biochemical,\\u000a physico-chemical, cell biological,

Michel B. Toledano; Agnes Delaunay; Benoit Biteau; Daniel Spector; Dulce Azevedo

131

Characterization of the Yeast Transcriptome  

Microsoft Academic Search

We have analyzed the set of genes expressed from the yeast genome, herein called the transcriptome, using serial analysis of gene expression. Analysis of 60,633 transcripts revealed 4,665 genes, with expression levels ranging from 0.3 to over 200 transcripts per cell. Of these genes, 1981 had known functions, while 2684 were previously uncharacterized. The integration of positional information with gene

Victor E. Velculescu; Lin Zhang; Wei Zhou; Jacob Vogelstein; Munira A. Basrai; Douglas E Bassett; Phil Hieter; Bert Vogelstein; Kenneth W. Kinzler

1997-01-01

132

Yeast strains for concentrated substrates  

Microsoft Academic Search

Summary  The screening of twenty yeast strains for ethanol productivity at high osmotic pressure at temperatures ranging from 32C\\u000a to 45C is described. Shake flask fermentations of 30, 40, and 50 Bx cane molasses were performed. The effect of temperature\\u000a on productivity at a non-inhibitory ethanol level is weakly pronounced. Most strains fermented poorly at 50 Bx molasses but\\u000a two Schizosaccharomyces

Åke Haraldson; Torsten Björling

1981-01-01

133

Investigating Wild Yeast Baking Potentials  

Microsoft Academic Search

2 Abstract: Yeast strains isolated from locally brewed beverages (Burukutu and Palm Wine) was identified to be Saccharomyces cerevisiae. They were tested for markers characteristics such as sugars fermentation ability, growth at elevated temperatures, growth in 3.0% NaCl,3.0% ethanol and 50.0% glucose were found to b e identical with the standard strain of Saccharomyces cerevisiae characteristically. The two isolates compared

A. Yabaya; E. D. Jatau

2009-01-01

134

Rheologically interesting polysaccharides from yeasts  

Microsoft Academic Search

We have examined the relationships between primary, secondary, and tertiary structures of polysaccharides exhibiting the rheological\\u000a property of friction (drag) reduction in turbulent flows. We found an example of an exopolysaccharide from the yeastCryptococcus laurentii that possessed high molecular weight but exhibited lower than expected drag reducing activity. Earlier correlations by Hoyt\\u000a (8,10) showing that ?1 ? 3, ??4, and

Gene R. Petersen; Gregory A. Nelson; Cheryl A. Cathey; Gerald G. Fuller

1989-01-01

135

Yeast genomics on food flavours  

Microsoft Academic Search

The appearance and concentration of the fusel alcohol 3-methyl-1-butanol is important for the flavour of fermented foods. 3-Methyl-1-butanol is formed by yeast during the conversion of L-leucine. Identification of the enzymes and genes involved in the formation of 3-methyl-1-butanol is a major prerequisite to optimize and control the final food flavour. To identify genes involved in this metabolic route, cDNA

Sung Ah Schoondermark-Stolk

2005-01-01

136

Interaction Between Yeasts and Zinc  

Microsoft Academic Search

Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a\\u000a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase.\\u000a The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard

Raffaele De Nicola; Graeme Walker

2009-01-01

137

Candida zeylanoides: Another Opportunistic Yeast  

Microsoft Academic Search

A patient witha longhistory ofscleroderma andgastrointestinal malabsorption requiring total parenteral nutrition was admitted withCandidazeylanoides fungemia. Theyeastresponded totherapy, buton two subsequent admissions forepisodes offeverthebloodcultures yielded thesame yeast.Theidentity ofthe Candida species was established biochemically byboththeAPI(Analytab) andViteksystemapproaches. C. zeylanoides ATCC20356andATCC7351served ascontrols forthese analyses andforantifungal susceptibility studies andrestriction endonuclease analyses ofchromosomal DNA. Theseinvestigations indicated that representative isolates oftheyeasts fromthethree episodes were identical anddiffered inseveral

DAVID LEVENSON; MICHAEL A. PFALLER; MIRIAM A. SMITH; RICHARD HOLLIS; TIM GERARDEN; CONNIE B. TUCCI; HENRY D. ISENBERG

1991-01-01

138

Emerging applications of the methylotrophic yeasts.  

PubMed

The use of methylotrophic yeasts for the production of single-cell-protein (SCP), alcohol oxidase and fine chemicals has been proposed. Fermentation technology developed for the growth of these yeasts on methanol at high cell densities has been commercialized. However, it is the production of heterologous recombinant proteins by Pichia pastoris that is emerging as the most significant application of the methylotrophic yeasts. PMID:2094288

Wegner, G H

1990-12-01

139

Yeasts in floral nectar: a quantitative survey  

PubMed Central

Background and Aims One peculiarity of floral nectar that remains relatively unexplored from an ecological perspective is its role as a natural habitat for micro-organisms. This study assesses the frequency of occurrence and abundance of yeast cells in floral nectar of insect-pollinated plants from three contrasting plant communities on two continents. Possible correlations between interspecific differences in yeast incidence and pollinator composition are also explored. Methods The study was conducted at three widely separated areas, two in the Iberian Peninsula (Spain) and one in the Yucatán Peninsula (Mexico). Floral nectar samples from 130 species (37–63 species per region) in 44 families were examined microscopically for the presence of yeast cells. For one of the Spanish sites, the relationship across species between incidence of yeasts in nectar and the proportion of flowers visited by each of five major pollinator categories was also investigated. Key Results Yeasts occurred regularly in the floral nectar of many species, where they sometimes reached extraordinary densities (up to 4 × 105 cells mm?3). Depending on the region, between 32 and 44 % of all nectar samples contained yeasts. Yeast cell densities in the order of 104 cells mm?3 were commonplace, and densities >105 cells mm?3 were not rare. About one-fifth of species at each site had mean yeast cell densities >104 cells mm?3. Across species, yeast frequency and abundance were directly correlated with the proportion of floral visits by bumble-bees, and inversely with the proportion of visits by solitary bees. Conclusions Incorporating nectar yeasts into the scenario of plant–pollinator interactions opens up a number of intriguing avenues for research. In addition, with yeasts being as ubiquitous and abundant in floral nectars as revealed by this study, and given their astounding metabolic versatility, studies focusing on nectar chemical features should carefully control for the presence of yeasts in nectar samples.

Herrera, Carlos M.; de Vega, Clara; Canto, Azucena; Pozo, Maria I.

2009-01-01

140

Production of ethanol by immobilized yeast cells  

Microsoft Academic Search

Saccharomyces cerevisiae cells were immobilized in calcium alginate beads for use in the continuous production of ethanol. Yeasts were grown in medium supplemented with ethanol to selectively screen for a culture which showed the greatest tolerance to ethanol inhibition. Yeast beads were produced from a yeast slurry containing 1.5% alginate (w\\/v) which was added as drops to a 0.05M CaCl2

David Williams; Douglas M. Munnecke

1981-01-01

141

Evaluation of Kluyveromyces marxianus as baker's yeast  

Microsoft Academic Search

Two strains of Kluyveromyces marxianus (NRRL-Y-2415 and NRRL-Y-1109) were assessed as baker's yeasts comparing them with two strains of Saccharomyces cerevisiae isolated respectively from compressed yeast and active dry yeast. Strains were tested for dough proofing activity in lean dough and rich doughs (prepared with sucrose, lactose or whey) and sensory evaluation of breads. In rich doughs containing lactose or

R. Caballero; P. Olguín; A. Cruz-Guerrero; F. Gallardo; M. García-Garibay; L. Gómez-Ruiz

1995-01-01

142

Yeast production from virgin grape marc  

Microsoft Academic Search

An alternative utilization of virgin grape marc (VGM) to produce SCP from S. cerevisiae is reported. A simple extraction method of fresh grape marc produces a sugar-rich solution; through fed-batch fermentation, a high-value yeast biomass instead of a low-value product like ethanol can be produced.Productivity and quality of yeast are similar to these obtainable from molasses. The convenience of yeast

R. B. Lo Curto; M. M. Tripodo

2001-01-01

143

Cell fusion assays for yeast mating pairs.  

PubMed

Yeast mating provides an accessible genetic system for the discovery of fundamental mechanisms in eukaryotic cell fusion. Although aspects of yeast mating related to pheromone signaling and polarized growth have been intensively investigated, fusion itself is poorly understood. This chapter describes methods for measuring the overall efficiency of yeast cell fusion and for monitoring various stages of the fusion process including cell wall remodeling, plasma membrane fusion, and nuclear fusion. PMID:18979244

Grote, Eric

2008-01-01

144

The yeast Golgi apparatus: insights and mysteries  

PubMed Central

The Golgi apparatus is known to modify and sort newly synthesized secretory proteins. However, fundamental mysteries remain about the structure, operation, and dynamics of this organelle. Important insights have emerged from studying the Golgi in yeasts. For example, yeasts have provided direct evidence for Golgi cisternal maturation, a mechanism that is likely to be broadly conserved. Here, we highlight features of the yeast Golgi as well as challenges that lie ahead.

Papanikou, Effrosyni; Glick, Benjamin S.

2009-01-01

145

High-Frequency Transformation of Yeast by Plasmids Containing the Cloned Yeast ARG4 Gene  

Microsoft Academic Search

Hybrid ColE1 plasmids, containing cloned DNA from the yeast ARG4 region [e.g., pYe(arg4)1], transform yeast arg4 mutants to ARG4+ with a frequency of 10-4 (about 103 transformants per mu g of plasmid DNA) and can replicate autonomously without integrating into the yeast genome. The yeast transformants are genetically unstable when grown on nonselective medium, but can be readily grown and

Chu-Lai Hsiao; John Carbon

1979-01-01

146

Rapid urea broth test for yeasts.  

PubMed Central

A rapid, miniaturized, urea broth test useful for detecting urease activity of yeasts was compared to Christensen urea agar. All urease-producing yeasts tested were positive on both media; however, 60% were reactive in the urea R broth within 30 min, and the remainder were reactive within 4 h. This urea multiwell test may be useful as a rapid screening method for detecting urease-producing yeasts recovered from clinical specimens and as an adjunct test with other rapid methods of yeast identification. Images

Roberts, G D; Horstmeier, C D; Land, G A; Foxworth, J H

1978-01-01

147

Lessons on longevity from budding yeast.  

PubMed

The past decade has seen fundamental advances in our understanding of the ageing process and raised optimism that interventions to slow ageing may be on the horizon. Studies of budding yeast have made immense contributions to this progress. Yeast longevity factors have now been shown to modulate ageing in invertebrate and mammalian models, and studies of yeast have resulted in some of the best candidates for anti-ageing drugs currently in development. The first interventions to slow human ageing may spring from the humble yeast. PMID:20336133

Kaeberlein, Matt

2010-03-25

148

Presence of glucosylceramide in yeast and its relation to alkali tolerance of yeast  

Microsoft Academic Search

Glycosylceramide is a membrane lipid that has physiological functions in eukaryotic organisms. The presence of glucosylceramide has been confirmed in some yeast; however, the extent of the role of glucosylceramide in yeast is unknown. Thus, the extent of presence of glucosylceramide in yeast was surveyed using 90 strains of 24 genera. The strains were divided into two groups according to

Katsuichi Saito; Naoya Takakuwa; Masao Ohnishi; Yuji Oda

2006-01-01

149

Characterisation of yeast microbial fuel cell with the yeast Arxula adeninivorans as the biocatalyst  

Microsoft Academic Search

Yeast microbial fuel cells have received little attention to date. Yeast should be ideal MFC catalyst because they are robust, easily handled, mostly non-pathogenic organisms with high catabolic rates and in some cases a broad substrate spectrum. Here we show that the non-conventional yeast Arxula adeninvorans transfers electrons to an electrode through the secretion of a reduced molecule that is

Nicholas D. Haslett; Frankie J. Rawson; Frèdèric Barriëre; Gotthard Kunze; Neil Pasco; Ravi Gooneratne; Keith H. R. Baronian

2011-01-01

150

Functional interaction of yeast elongation factor 3 with yeast ribosomes.  

PubMed

Elongation factor 3 (EF-3) is a unique and essential requirement of the fungal translational apparatus. EF-3 is a monomeric protein with a molecular mass of 116,000. EF-3 is required by yeast ribosomes for in vitro translation and for in vivo growth. The protein stimulates the binding of EF-1 alpha :GTP:aa-tRNA ternary complex to the ribosomal A-site by facilitating release of deacylated-tRNA from the E-site. The reaction requires ATP hydrolysis. EF-3 contains two ATP-binding sequence motifs (NBS). NBSI is sufficient for the intrinsic ATPase function. NBSII is essential for ribosome-stimulated activity. By limited proteolysis, EF-3 was divided into two distinct functional domains. The N-terminal domain lacking the highly charged lysine blocks failed to bind ribosomes and was inactive in the ribosome-stimulated ATPase activity. The C-terminally derived lysine-rich fragment showed strong binding to yeast ribosomes. The purported S5 homology region of EF-3 at the N-terminal end has been reported to interact with 18S ribosomal RNA. We postulate that EF-3 contacts rRNA and/or protein(s) through the C-terminal end. Removal of these residues severely weakens its interaction mediated possibly through the N-terminal domain of the protein. PMID:10216951

Chakraburtty, K

1999-01-01

151

Spoilage yeasts in the wine industry.  

PubMed

Yeasts play a central role in the spoilage of foods and beverages, mainly those with high acidity and reduced water activity (a(w)). A few species are capable of spoiling foods produced according to good manufacturing practices (GMPs). These can survive and grow under stress conditions where other microorganisms are not competitive. However, many of the aspects determining yeast spoilage have yet to be clarified. This critical review uses the wine industry as a case study where serious microbiological problems are caused by yeasts. First, the limitations of the available tools to assess the presence of spoilage yeasts in foods are discussed. Next, yeasts and factors promoting their colonisation in grapes and wines are discussed from the ecological perspective, demonstrating that a deeper knowledge of vineyard and winery ecosystems is essential to establish the origin of wine spoilage yeasts, their routes of contamination, critical points of yeast infection, and of course, their control. Further, zymological indicators are discussed as important tools to assess the microbiological quality of wines, although they are rarely used by the wine industry. The concepts of the susceptibility of wine to spoilage yeasts and wine stability are addressed based on scientific knowledge and industrial practices for monitoring yeast contamination. A discussion on acceptable levels of yeasts and microbiological criteria in the wine industry is supported by data obtained from wineries, wholesalers, and the scientific literature.Finally, future directions for applied research are proposed, involving collaboration between scientists and industry to improve the quality of wine and methods for monitoring the presence of yeast. PMID:12892920

Loureiro, V; Malfeito-Ferreira, M

2003-09-01

152

Experimental evolution in budding yeast  

NASA Astrophysics Data System (ADS)

I will discuss our progress in analyzing evolution in the budding yeast, Saccharomyces cerevisiae. We take two basic approaches. The first is to try and examine quantitative aspects of evolution, for example by determining how the rate of evolution depends on the mutation rate and the population size or asking whether the rate of mutation is uniform throughout the genome. The second is to try to evolve qualitatively novel, cell biologically interesting phenotypes and track the mutations that are responsible for the phenotype. Our efforts include trying to alter cell morphology, evolve multicellularity, and produce a biological oscillator.

Murray, Andrew

2012-02-01

153

Functional analysis of the yeast genome  

Microsoft Academic Search

The release of the complete genome sequence of the yeast Saccharomyces cerevisiae has ushered in a new phase of genome research in which sequence function will be assigned. The goal is to determine the biological function of each of the >6,000 open reading frames in the yeast genome. Innovative approaches have been developed that exploit the sequence data and yield

Elizabeth A Winzeler; Ronald W Davist

1997-01-01

154

3 Baker's yeast: challenges and future prospects  

Microsoft Academic Search

In the past few years, recombinant DNA technology has led to the apparition of new baker's yeast strains, which have optimized or novel properties, and in the near future, it is expected that this tool will produce a huge spectrum of specialized yeasts of high added value. Their introduction in the manufacturing market will produce a dramatic Change in formulation,

Francisca Randez-Gil; Jaime Aguilera; Antonio Codón; Ana M. Rincón; Francisco Estruch; José A. Prieto

155

Characterization of wine yeasts for ethanol production  

Microsoft Academic Search

Selected wine yeasts were tested for their ethanol and sugar tolerance, and for their fermentative capacity. Growth (µ) and fermentation rates (?) were increasingly inhibited by increasing ethanol and glucose concentrations, “flor” yeasts being the least inhibited. Except in the latter strains, the ethanol production rate was accelerated by adding the glucose stepwise. The best fermenting strains selected in laboratory

Juan Jiménez; Tahía Benítez

1986-01-01

156

Characterization of wine yeasts for ethanol production  

Microsoft Academic Search

Summary Selected wine yeasts were tested for their ethanol and sugar tolerance, and for their fermentative capacity. Growth (µ) and fermentation rates (?) were increasingly inhibited by increasing ethanol and glucose concentrations, “flor” yeasts being the least inhibited. Except in the latter strains, the ethanol production rate was accelerated by adding the glucose stepwise. The best fermenting strains selected in

Juan Jiménez; Tahía Benítez

1986-01-01

157

Yeast: An Experimental Organism for Modern Biology.  

ERIC Educational Resources Information Center

|Discusses the applicability and advantages of using yeasts as popular and ideal model systems for studying and understanding eukaryotic biology at the cellular and molecular levels. Cites experimental tractability and the cooperative tradition of the research community of yeast biologists as reasons for this success. (RT)|

Botstein, David; Fink, Gerald R.

1988-01-01

158

TAXONOMY AND PHYLOGENETIC DIVERSITY AMONG THE YEASTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Yeasts are fungi that predominantly exist as unicellular organisms. However, some yeasts can become multicellular through formation of strands of elongated buds known as pseudohyphae, or through the formation of true hyphae that have well developed crosswalls like those seen in typical filamentous ...

159

The oenological characteristics of commercial dry yeasts  

Microsoft Academic Search

Twenty preparations of dry active yeast (18 Saccharomyces cerevisiae and two Saccharomyces bayanus) available in Italy were tested in white and red musts (Moscato, Albana and Sangiovese) to study their oenological characteristics (i.e. fermentation rate, total alcohol and acetic acid production). After the application of chemiometric techniques for descriptive analyses to the results of the oenological assessment, the yeasts were

Giuseppe Comi; Isabella Croattini; Marilena Marino; Michela Maifreni; Roberto Zironi

1997-01-01

160

Oily yeasts as oleaginous cell factories.  

PubMed

Oily yeasts have been described to be able to accumulate lipids up to 20% of their cellular dry weight. These yeasts represent a minor proportion of the total yeast population, and only 5% of them have been reported as able to accumulate more than 25% of lipids. The oily yeast genera include Yarrowia, Candida, Rhodotorula, Rhodosporidium, Cryptococcus, Trichosporon, and Lipomyces. More specifically, examples of oleaginous yeasts include the species: Lipomyces starkeyi, Rhodosporidium toruloides, Rhodotorula glutinis, and Yarrowia lipolytica. Yeast do exhibit advantages for lipid production over other microbial sources, namely, their duplication times are usually lower than 1 h, are much less affected than plants by season or climate conditions, and their cultures are more easily scaled up than those of microalgae. Additionally, some oily yeasts have been reported to accumulate oil up to 80% of their dry weight and can indeed generate different lipids from different carbon sources or from lipids present in the culture media. Thus, they can vary their lipid composition by replacing the fatty acids present in their triglycerides. Due to the diversity of microorganisms and growth conditions, oily yeasts can be useful for the production of triglycerides, surfactants, or polyunsaturated fatty acids. PMID:21465305

Ageitos, Jose Manuel; Vallejo, Juan Andres; Veiga-Crespo, Patricia; Villa, Tomas G

2011-04-05

161

Protein Function, Connectivity, and Duplicability in Yeast  

Microsoft Academic Search

Protein-protein interaction networks have evolved mainly through connectivity rewiring and gene duplication. However, how protein function influences these processes and how a network grows in time have not been well studied. Using protein-protein interaction data and genomic data from the budding yeast, we first examined whether there is a correlation between the age and connectivity of yeast proteins. A steady

Anuphap Prachumwat; Wen-Hsiung Li

2005-01-01

162

Production of recombinant proteins by yeast cells  

Microsoft Academic Search

Yeasts are widely used in production of recombinant proteins of medical or industrial interest. For each individual product, the most suitable expression system has to be identified and optimized, both on the genetic and fermentative level, by taking into account the properties of the product, the organism and the expression cassette. There is a wide range of important yeast expression

Eda Çelik; P?nar Çal?k

163

CYGD: the Comprehensive Yeast Genome Database  

Microsoft Academic Search

The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, cho- sen as the best understood model organism for eukar- yotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual

Ulrich Güldener; Martin Münsterkötter; Gabi Kastenmüller; Normann Strack; Jacques Van Helden; Christian Lemer; J. Richelles; Shoshana J. Wodak; J. García-martínez; J. E. Pérez-ortín; Holger Michael; Andreas Kaps; E. Talla; Bernard Dujon; B. André; J. L. Souciet; J. De Montigny; E. Bon; C. Gaillardin; Hans-werner Mewes

2005-01-01

164

Growth Requirements of San Francisco Sour Dough Yeasts and Bakers' Yeast  

PubMed Central

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.

Henry, NG

1976-01-01

165

Anhydrobiosis in yeast: influence of calcium and magnesium ions on yeast resistance to dehydration-rehydration.  

PubMed

The influence of calcium and magnesium ions on resistance to dehydration in the yeast, Saccharomyces cerevisiae, was investigated. Magnesium ion availability directly influenced yeast cells' resistance to dehydration and, when additionally supplemented with calcium ions, this provided further significant increase of yeast resistance to dehydration. Gradual rehydration of dry yeast cells in water vapour indicated that both magnesium and calcium may be important for the stabilization of yeast cell membranes. In particular, calcium ions were shown for the first time to increase the resistance of yeast cells to dehydration in stress-sensitive cultures from exponential growth phases. It is concluded that magnesium and calcium ion supplementations in nutrient media may increase the dehydration stress tolerance of S. cerevisiae cells significantly, and this finding is important for the production of active dry yeast preparations for food and fermentation industries. PMID:20487021

Trofimova, Yuliya; Walker, Graeme; Rapoport, Alexander

2010-04-14

166

Ultrastructural organization of yeast chromatin  

PubMed Central

The ultrastructural organization of yeast chromatin was examined in Miller spread preparations of samples prepared from spheroplasts or isolated nuclei of Saccharomyces cerevisiae. Micrographs from preparations dispersed in 1 mM Tris (pH 7.2) illustrate that the basic chromatin fiber in yeast exists in two ultrastructurally distinct conformations. The majority (up to 95%) of the chromatin displays a beaded nucleosomal organization, although adjacent nucleosomes are separated by internucleosomal linkers of variable lengths. Ribonucleoprotein (RNP) fibrils are only occasionally associated with chromatin displaying the conformation. The remaining 5-10% of the chromatin appears to be devoid of discrete nucleosomes and has a smooth contour with a fiber diameter of 30-40 A. Transcriptional units, including putative ribosomal precursor RNA genes, defined by the presence of nascent RNP fibrils are restricted to chromatin displaying this smooth morphology. Chromatin released from nuclei in the presence of 5 mM Mg++ displays higher-order chromatin fibers, 200-300 A in diameter, these fibers appear to be arranged in a manner than reflects the two forms of the basic chromatin fiber.

1982-01-01

167

Yeast community survey in the Tagus estuary.  

PubMed

The yeast community in the waters of the Tagus estuary, Portugal, was followed for over a year in order to assess its dynamics. Yeast occurrence and incidence were measured and this information was related to relevant environmental data. Yeast occurrence did not seem to depend upon tides, but river discharge had a dramatic impact both on the density and diversity of the community. The occurrence of some yeasts was partially correlated with faecal pollution indicators. Yeast isolates were characterized by microsatellite primed PCR (MSP-PCR) fingerprinting and rRNA gene sequencing. The principal species found were Candida catenulata, C. intermedia, C. parapsilosis, Clavispora lusitaniae, Debaryomyces hansenii, Pichia guilliermondii, Rhodotorula mucilaginosa and Rhodosporidium diobovatum. The incidence of these species was evaluated against the environmental context of the samples and the current knowledge about the substrates from which they are usually isolated. PMID:16329949

de Almeida, João M G C F

2005-07-01

168

Yeasts and yeast-like fungi associated with tree bark: diversity and identification of yeasts producing extracellular endoxylanases.  

PubMed

A total of 239 yeast strains was isolated from 52 tree bark samples of the Medaram and Srisailam forest areas of Andhra Pradesh, India. Based on analysis of D1/D2 domain sequence of 26S rRNA gene, 114 strains were identified as ascomycetous; 107 strains were identified as basidiomycetous yeasts; and 18 strains were identified as yeast-like fungi. Among the ascomycetous yeasts, 51% were identified as members of the genus Pichia, and the remaining 49% included species belonging to the genera Clavispora, Debaryomyces, Kluyveromyces, Hanseniaspora, Issatchenkia, Lodderomyces, Kodamaea, Metschnikowia, and Torulaspora. The predominant genera in the basidiomycetous yeasts were Cryptococcus (48.6%), Rhodotorula (29%), and Rhodosporidium (12.1%). The yeast-like fungi were represented by Aureobasidium pullulans (6.7%) and Lecythophora hoffmanii (0.8%). Of the 239 yeast strains tested for Xylanase, only five strains of Aureobasidium sp. produced xylanase on xylan-agar medium. Matrix-assisted laser desorption ionization-time of flight analysis and N-terminal amino-acid sequence of the xylanase of isolate YS67 showed high similarity with endo-1-4-beta-xylanase (EC 3.2.1.8) of Aureobasidium pullulans var. melanigenum. PMID:18219522

Bhadra, Bhaskar; Rao, R Sreenivas; Singh, Pavan K; Sarkar, Partha K; Shivaji, Sisinthy

2008-01-25

169

Optical Tweezing of Yeast Cells  

NASA Astrophysics Data System (ADS)

Optical Tweezers is a powerful technique that aids in understanding and applying the unique principles of photonics, optical physics, and basic cell biology. The experiments presented involve using HeNe lasers (632.8 nm) to trap spherical and ovular shaped objects in a solution. Polystyrene spheres, six micrometers in diameter, were trapped and moved with the laser to calibrate our system. The spheres were submerged in a Sodium Phosphate buffer solution to prevent sticking. Saccharomyces cerevisae, better known as yeast, was grown in a glucose rich environment to reach sizes of four to nine micrometers. Our optical tweezers captured and moved these cells under the operators command. A two laser system was utilized to control two cells simultaneously and attempt the splitting of cells. )

Gilroy, Kyle; Ochoa, Romulo

2010-02-01

170

Accelerating Yeast Prion Biology using Droplet Microfluidics  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

171

The osmotic stress tolerance of basidiomycetous yeasts.  

PubMed

The growth and accumulation of intracellular polyols at reduced water activity (a(w)) were studied in 40 basidiomycetous yeast strains. The growth of most strains showed greater tolerance to NaCl than sorbitol at the same a(w). No strain was able to grow below 0.90a(w). (13)C nuclear magnetic resonance spectroscopy revealed that glycerol was the major solute accumulated intracellularly by all the yeasts when grown to 0.96a(w) (NaCl). Arabitol or mannitol was also accumulated in some yeasts, whereas a few only accumulated glycerol. Analysis of six yeasts in detail revealed that the intracellular glycerol concentrations of five yeasts increased significantly when grown at 0.96a(w) (NaCl or sorbitol) compared with growth at 0.998a(w). Arabitol and mannitol concentrations also increased, but not to the same degree. Intracellular potassium concentrations decreased when grown at 0.96a(w) (NaCl or sorbitol) and sodium increased, but only when grown at 0.96a(w) (NaCl). The survival of nine strains was evaluated in soil cultures and it was found that all grew at 100% field capacity, whereas at lower field capacity, only some strains grew or survived. The growth of basidiomycetous yeasts appears to be more sensitive to reduced a(w) than ascomycetous yeasts. PMID:20214685

Tekolo, Obakeng M; McKenzie, Jean; Botha, Alfred; Prior, Bernard A

2010-02-26

172

Hydrogen Peroxide Metabolism in Yeasts  

PubMed Central

A catalase-negative mutant of the yeast Hansenula polymorpha consumed methanol in the presence of glucose when the organism was grown in carbon-limited chemostat cultures. The organism was apparently able to decompose the H2O2 generated in the oxidation of methanol by alcohol oxidase. Not only H2O2 generated intracellularly but also H2O2 added extracellularly was effectively destroyed by the catalase-negative mutant. From the rate of H2O2 consumption during growth in chemostat cultures on mixtures of glucose and H2O2, it appeared that the mutant was capable of decomposing H2O2 at a rate as high as 8 mmol · g of cells?1 · h?1. Glutathione peroxidase (EC 1.11.1.9) was absent under all growth conditions. However, cytochrome c peroxidase (CCP; EC 1.11.1.5) increased to very high levels in cells which decomposed H2O2. When wild-type H. polymorpha was grown on mixtures of glucose and methanol, the CCP level was independent of the rate of methanol utilization, whereas the level of catalase increased with increasing amounts of methanol in the substrate feed. Also, the wild type decomposed H2O2 at a high rate when cells were grown on mixtures of glucose and H2O2. In this case, an increase of both CCP and catalase was observed. When Saccharomyces cerevisiae was grown on mixtures of glucose and H2O2, the level of catalase remained low, but CCP increased with increasing rates of H2O2 utilization. From these observations and an analysis of cell yields under the various conditions, two conclusions can be drawn. (i) CCP is a key enzyme of H2O2 detoxification in yeasts. (ii) Catalase can effectively compete with mitochondrial CCP for hydrogen peroxide only if hydrogen peroxide is generated at the site where catalase is located, namely in the peroxisomes.

Verduyn, Cornelis; Giuseppin, Marco L. F.; Scheffers, W. Alexander; van Dijken, Johannes P.

1988-01-01

173

Adhesive interactions between medically important yeasts and bacteria  

Microsoft Academic Search

Yeasts are being increasingly identified as important organisms in human infections. Adhesive interactions between yeasts and bacteria may contribute to yeast retention at body sites. Methods for studying adhesive interactions between bacterial strains are well known, and range from simple macroscopic methods to flow chamber systems with complex image analysis capabilities. The adhesive interactions between bacteria and yeasts have been

Kevin W. Millsap; Henny C. van der Mei; Rolf Bos; Henk J. Busscher

1998-01-01

174

Physiological and Molecular Responses of Yeasts to the Environment  

Microsoft Academic Search

Understanding the ways by which yeasts respond to changes in their physicochemical environment is very important in the food and beverage industries. For example, it is important for the maintenance of yeast viability and vitality in the production and utilisation of yeasts for food and fermentation processes, and it is additionally important for the control of yeasts that act as

GRAEME M. WALKER; PATRICK VAN DIJCK

175

Pleiotropic Signaling Pathways Orchestrate Yeast Development  

PubMed Central

Developmental phenotypes in Saccharomyces cerevisiae and related yeasts include responses such as filamentous growth, sporulation, and the formation of biofilms and complex colonies. These developmental phenotypes are regulated by evolutionarily conserved, nutrient-responsive signaling networks. The signaling mechanisms that control development in yeast are highly pleiotropic – all of the known pathways contribute to the regulation of multiple developmental outcomes. This degree of pleiotropy implies that perturbations of these signaling pathways, whether genetic, biochemical or environmentally induced, can manifest in multiple (and sometimes unexpected) ways. We summarize the current state of knowledge of developmental pleiotropy in yeast and discuss its implications for understanding functional relationships.

Granek, Joshua A.; Kay?kc?, Omur

2011-01-01

176

Yeast display of engineered antibody domains.  

PubMed

Yeast display is an efficient technology for selection of antibodies and other proteins with high affinity and thermal stability. Here, we describe a method for affinity maturation of engineered antibody domains (eAds) using yeast display. EAd yeast libraries of relatively large size (?10?) were generated and subjected to alternating rounds of magnetic-activated cell sorting (MACS), fluorescent-activated cell sorting (FACS), and random mutagenesis. The highest affinity clones from the final round of maturation were identified and analyzed. We discuss extensively each key step, and provide detailed protocols and helpful notes. PMID:22735947

Zhao, Qi; Zhu, Zhongyu; Dimitrov, Dimiter S

2012-01-01

177

Arachidonic acid metabolites in pathogenic yeasts  

PubMed Central

Although most of what is known about the biology and function of arachidonic acid metabolites comes from the study of mammalian biology, these compounds can also be produced by lower eukaryotes, including yeasts and other fungi. It is also in this group of organisms that the least is known about the metabolic pathways leading to the production of these compounds as well as the functions of these compounds in the biology of fungi and yeasts. This review will deal with the discovery of oxylipins from polyunsaturated fatty acids, and more specifically the arachidonic acid derived eicosanoids, such as 3-hydroxy eicosatetraenoic acid, prostaglandin F2? and prostaglandin E2, in yeasts starting in the early 1990s. This review will also focus on what is known about the metabolic pathways and/or proteins involved in the production of these compounds in pathogenic yeasts. The possible roles of these compounds in the biology, including the pathology, of these organisms will be discussed.

2012-01-01

178

Functional analysis of the yeast genome  

Microsoft Academic Search

.   Just as Saccharomyces cerevisiae itself provides a model for so many processes essential to eukaryotic life, we anticipate that the methods and the mindset\\u000a that have moved yeast biological research \\

Petra Ross-Macdonald

2000-01-01

179

Immobilized Yeasts: Growth and Metabolism, Alcohol Fermentation.  

National Technical Information Service (NTIS)

The reaction characteristics of Saccharomyces uvarum immobilized in solid supports are presented. Two types of solid supports are used, porous brick and porous silica. Yeast adsorption and covalent coupling, influence of pore size on adsorption are evalua...

J. M. Navarro

1980-01-01

180

Propagation of Mammalian Prions in Yeast.  

National Technical Information Service (NTIS)

The focus of this grant is on development of a novel model system for propagation and quantitation of mammalian prions: the budding yeast Saccharomyces cerevisiae. This unicellular organism offers a number of potential advantages for the study of prion bi...

D. A. Harris

2006-01-01

181

[Regulation of gene expression in methylotrophic yeasts].  

PubMed

Methylotrophic yeasts are unique eukaryotic organisms, that can metabolize toxic one-carbon substrate, methyl alcohol or methanol. About 50 species of methylotrophic yeasts is known, among them 4 species are the best studied: Pichia methanolica, Hansenula polymorpha, Pichia pastoris i Candida boidinii. These organisms, especially P. pastoris i H. polymorpha appeared to be very perspective overproducers of heterologous proteins and nowadays are used for industrial production of some of them. In this review, we provide information on the organization of the genome, mechanisms of regulation of gene expression and the use of strong promoters of these yeast species to construct the producers of heterologous proteins. In more details, we analyze genetic control of carbon and nitrogen catabolic repression in H. polymorpha and also the identification of metabolites inducing catabolite repression or peroxisome selective autophagy in the medium with ethanol in the Pichia methanolica yeast. PMID:23821948

Grabek-Lejko, Dorota; Sibirny, Vladimir; Sibirny, Andriy

2013-01-01

182

Monitoring Air Quality with Leaf Yeasts.  

ERIC Educational Resources Information Center

|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)|

Richardson, D. H. S.; And Others

1985-01-01

183

Yeast Screens for Treatment of Human Disease.  

National Technical Information Service (NTIS)

Screening methods for identifying substances that provide therapeutic value for various diseases associated with protein misfolding are provided. Genetic and chemical screening methods are provided using a yeast system. The methods of the invention provid...

S. Krobitsch S. Lindquist T. F. Outeiro

2006-01-01

184

ENGINEERING THE BIOSYNTHESIS OF STYRENE IN YEAST  

EPA Science Inventory

The strategy pursued was to insert genes for phenylalanine ammonia lysase (pal) and phenolic acid decarboxylase (pad) into the yeast that would convert phenylalanine to styrene through a cinnamic acid intermediate. ...

185

CYGD: the Comprehensive Yeast Genome Database.  

PubMed

The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, chosen as the best understood model organism for eukaryotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual genes and proteins. In addition, it provides information on the physical and functional interactions among proteins as well as other genetic elements. These cellular networks include metabolic and regulatory pathways, signal transduction and transport processes as well as co-regulated gene clusters. As more yeast genomes are published, their annotation becomes greatly facilitated using S.cerevisiae as a reference. CYGD provides a way of exploring related genomes with the aid of the S.cerevisiae genome as a backbone and SIMAP, the Similarity Matrix of Proteins. The comprehensive resource is available under http://mips.gsf.de/genre/proj/yeast/. PMID:15608217

Güldener, U; Münsterkötter, M; Kastenmüller, G; Strack, N; van Helden, J; Lemer, C; Richelles, J; Wodak, S J; García-Martínez, J; Pérez-Ortín, J E; Michael, H; Kaps, A; Talla, E; Dujon, B; André, B; Souciet, J L; De Montigny, J; Bon, E; Gaillardin, C; Mewes, H W

2005-01-01

186

CYGD: the Comprehensive Yeast Genome Database  

PubMed Central

The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, chosen as the best understood model organism for eukaryotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual genes and proteins. In addition, it provides information on the physical and functional interactions among proteins as well as other genetic elements. These cellular networks include metabolic and regulatory pathways, signal transduction and transport processes as well as co-regulated gene clusters. As more yeast genomes are published, their annotation becomes greatly facilitated using S.cerevisiae as a reference. CYGD provides a way of exploring related genomes with the aid of the S.cerevisiae genome as a backbone and SIMAP, the Similarity Matrix of Proteins. The comprehensive resource is available under http://mips.gsf.de/genre/proj/yeast/.

Guldener, U.; Munsterkotter, M.; Kastenmuller, G.; Strack, N.; van Helden, J.; Lemer, C.; Richelles, J.; Wodak, S. J.; Garcia-Martinez, J.; Perez-Ortin, J. E.; Michael, H.; Kaps, A.; Talla, E.; Dujon, B.; Andre, B.; Souciet, J. L.; De Montigny, J.; Bon, E.; Gaillardin, C.; Mewes, H. W.

2005-01-01

187

Ethanol inhibition of continuous anaerobic yeast growth  

Microsoft Academic Search

The inhibitory effect of ethanol on the yeast Saccharomyces cerevisiae ATCC 4126 has been studied in continuous culture under conditions where high concentrations of ethanol were produced by the yeast itself. The fermentations were carried out using a glucose, salts medium at glucose concentrations of 20, 100 and 200 gl-1. The growth function\\u000a$$\\\\mu = \\\\hat \\\\mu \\\\cdot \\\\frac{{C_s }}{{K_s

Gerhard K Hoppe; Geoffrey S Hansford

1982-01-01

188

Arsenic metabolism in marine bacteria and yeast  

Microsoft Academic Search

Arsenic metabolism was studied for two marine microorganisms, a facultative anaerobic bacterium, Serratia marinorubra, and an obligately aerobic yeast, Rhodotorula rubra. Both were cultivated in media with (74As) arsenate (As V), and the products of arsenate metabolism were determined qualitatively. Both the bacterium and the yeast produced arsenite (AS III) and methylarsonic acid [CH3AsO(OH)2]. In addition to the foregoing, only

F. V. Vidal; V. M. V. Vidal

1980-01-01

189

How To Make Yeast Cells Thrive  

NSDL National Science Digital Library

Students set up and run the experiments they designed in the lesson Population Growth in Yeasts, using simple yeast-molasses cultures in test tubes. Population growth is indicated by the amount of respiration occurring in the cultures, which in turn is indicated by the growth of carbon dioxide bubbles trapped within the culture tubes. Using this method, students can test for a variety of environmental influences, such as temperature, food supply, and pH.

Engineering K-Ph.d. Program

190

Featured Organism: Schizosaccharomyces pombe, The Fission Yeast  

PubMed Central

Schizosaccharomyces pombe, the fission yeast, has long been a crucial model for the study of the eukaryote cell cycle. We take a look at this important yeast, whose genome has recently been completed, featuring comments from Valerie Wood, Jürg Bähler, Ramsay McFarlane, Susan Forsburg, Iain Hagan and Paul Nurse on the implications of having the complete sequence and future prospects for pombe genomics.

2002-01-01

191

Mitochondria, metabolism, and aging in yeast  

Microsoft Academic Search

\\u000a Quantitative and qualitative changes in metabolism take place when the lifespan is extended in yeast either by genetic or\\u000a nutritional manipulation. In particular, remodeling of mitochondrial function occurs, and the relationship between this organelle\\u000a and other cellular compartments moves to the fore. Two separate pathways, the retrograde response and calorie restriction,\\u000a operate as metabolic mechanisms for life extension in yeast.

S. Michal Jazwinski

192

A yeast biosensor for glucose determination  

Microsoft Academic Search

A yeast potentiometric biosensor for glucose determination is described. After induction of glycolytic enzyme synthesis a cell suspension of the yeast Hansenula anomala is retained in calcium alginate gel on the surface of a glass electrode. This biosensor gives a Nernstian response in glucose concentration of 5·10-4–5·10-3 mol\\/l with a response time of 5 min and a life-time of at

Jaroslav Racek

1991-01-01

193

Whey Alcohol Fermentation with Mixed Yeast Cultures  

Microsoft Academic Search

This paper study the process of whey alcohol fermentation with mixed yeasts cultures. After the experiments of strains combination, the yeast strains of Saccharomyces uvarum TY-3, Saccharomyces uvarum TY-1 and Saccharomyces carlsbergensis AY-5 were selected and mixed at the ratio of 5.0:2.5:2.5. The optimized fermenting condition was obtained through orthogonal experiments with the result as follows: the initial pH value

Wang Jianming; Guo Linhai; Zhao Guoren

2009-01-01

194

The secretory pathway: exploring yeast diversity.  

PubMed

Protein secretion is an essential process for living organisms. In eukaryotes, this encompasses numerous steps mediated by several hundred cellular proteins. The core functions of translocation through the endoplasmic reticulum membrane, primary glycosylation, folding and quality control, and vesicle-mediated secretion are similar from yeasts to higher eukaryotes. However, recent research has revealed significant functional differences between yeasts and mammalian cells, and even among diverse yeast species. This review provides a current overview of the canonical protein secretion pathway in the model yeast Saccharomyces cerevisiae, highlighting differences to mammalian cells as well as currently unresolved questions, and provides a genomic comparison of the S. cerevisiae pathway to seven other yeast species where secretion has been investigated due to their attraction as protein production platforms, or for their relevance as pathogens. The analysis of Candida albicans, Candida glabrata, Kluyveromyces lactis, Pichia pastoris, Hansenula polymorpha, Yarrowia lipolytica, and Schizosaccharomyces pombe reveals that many - but not all - secretion steps are more redundant in S. cerevisiae due to duplicated genes, while some processes are even absent in this model yeast. Recent research obviates that even where homologous genes are present, small differences in protein sequence and/or differences in the regulation of gene expression may lead to quite different protein secretion phenotypes. PMID:23480475

Delic, Marizela; Valli, Minoska; Graf, Alexandra B; Pfeffer, Martin; Mattanovich, Diethard; Gasser, Brigitte

2013-04-12

195

Phylogenetics of Saccharomycetales, the ascomycete yeasts.  

PubMed

Ascomycete yeasts (phylum Ascomycota: subphylum Saccharomycotina: class Saccharomycetes: order Saccharomycetales) comprise a monophyletic lineage with a single order of about 1000 known species. These yeasts live as saprobes, often in association with plants, animals and their interfaces. A few species account for most human mycotic infections, and fewer than 10 species are plant pathogens. Yeasts are responsible for important industrial and biotechnological processes, including baking, brewing and synthesis of recombinant proteins. Species such as Saccharomyces cerevisiae are model organisms in research, some of which led to a Nobel Prize. Yeasts usually reproduce asexually by budding, and their sexual states are not enclosed in a fruiting body. The group also is well defined by synapomorphies visible at the ultrastructural level. Yeast identification and classification changed dramatically with the availability of DNA sequencing. Species identification now benefits from a constantly updated sequence database and no longer relies on ambiguous growth tests. A phylogeny based on single gene analyses has shown the order to be remarkably divergent despite morphological similarities among members. The limits of many previously described genera are not supported by sequence comparisons, and multigene phylogenetic studies are under way to provide a stable circumscription of genera, families and orders. One recent multigene study has resolved species of the Saccharomycetaceae into genera that differ markedly from those defined by analysis of morphology and growth responses, and similar changes are likely to occur in other branches of the yeast tree as additional sequences become available. PMID:17486976

Suh, Sung-Oui; Blackwell, Meredith; Kurtzman, Cletus P; Lachance, Marc-André

196

Inhibition of yeast glutathione reductase by trehalose: possible implications in yeast survival and recovery from stress  

Microsoft Academic Search

Accumulation of trehalose has been implicated in the tolerance of yeast cells to several forms of stress, including heat-shock and high ethanol levels. However, yeast lacking trehalase, the enzyme that degrades trehalose, exhibit poor survival after exposure to stress conditions. This suggests that optimal cell viability also depends on the capacity to rapidly degrade the high levels of trehalose that

Adriano Sebollela; Paulo Roberto Louzada; Mauro Sola-Penna; Verietta Sarone-Williams; Tatiana Coelho-Sampaio; Sérgio T. Ferreira

2004-01-01

197

Utilisation of spent brewer's yeast for yeast extract production by autolysis: The effect of temperature  

Microsoft Academic Search

In this study, autolysis was induced by incubating cell suspensions of spent brewer's yeast at elevated temperatures of 45, 50, 55 and 60°C with a reaction time ranging from 8 to 72h. Contents and yields of solid, ?-amino nitrogen, protein and carbohydrate were determined. It can be said that optimum temperature and time for the production of yeast extract was

Hasan Tanguler; Huseyin Erten

2008-01-01

198

The Effect of Different Temperatures on Autolysis of Baker's Yeast for the Production of Yeast Extract  

Microsoft Academic Search

This study aimed to determine the optimum autolysis conditions for the production of yeast extract, which is used to give a meaty flavor to food products and to increase their nutritional value. Autolysis was induced by incubating baker's yeast cell suspensions at different temperatures (45, 50, 55, and 60 °C) with a reaction time ranging from 8 to 72 h.

Hasan TANGÜLER; Hüseyin ERTEN

199

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

PubMed Central

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.

Kazemzadeh, Laleh; Cvijovic, Marija; Petranovic, Dina

2012-01-01

200

The 26S proteasome degrades mouse and yeast ornithine decarboxylase in yeast cells.  

PubMed

Eukaryotic cells possess two high-molecular-mass proteases, the 700 kDa, 20S proteasome, as well as the even larger 1,400 kDa, 26S proteasome. It has been demonstrated that ornithine decarboxylase is degraded, in vitro, by the 26S proteasome that contains the 20S protease as its catalytic core, but not by the free 20S proteasome. Recently, by demonstrating severe inhibition of mouse and yeast ODC degradation in a mutant yeast cell line, defective in the chymotripsin-like activity of the yeast 20S proteasome, we implicated the 20S proteasome in the degradation of ODC, in vivo, in yeast cells. Here we show that the degradation of ODC is also severely inhibited in the mutant yeast cell lines, cim3-1 and cim5-1, containing a specific lesion in subunits that are unique to the yeast 26S proteasome. We therefore, conclude, that as illustrated in vitro, also in intact cells, it is the 26S proteasome, not the free 20S proteasome, that degrades ODC. We also demonstrate, that while deficiency in the proteasome chymotrypsine-like activity (in the yeast pre1-1 mutant) inhibits the degradation of both yeast and mouse ODCs, deficiency in the peptidyl-glutamyl-peptide-hydrolyzing (PGPH) activity inhibits only yeast ODC degradation. Similarly, we have noted that whereas the putative ATPase activity of both the CIM3 and CIM5 subunits is essential for the degradation of mouse ODC, only that of the CIM3 subunit is required for the degradation of yeast ODC. These results suggest differential utilization of individual proteasomal subunits in the recognition and degradation of individual short-lived proteins. PMID:7805829

Mamroud-Kidron, E; Kahana, C

1994-12-19

201

Mitochondrial membrane lipidome defines yeast longevity.  

PubMed

Our studies revealed that lithocholic acid (LCA), a bile acid, is a potent anti-aging natural compound that in yeast cultured under longevity-extending caloric restriction (CR) conditions acts in synergy with CR to enable a significant further increase in chronological lifespan. Here, we investigate a mechanism underlying this robust longevity-extending effect of LCA under CR. We found that exogenously added LCA enters yeast cells, is sorted to mitochondria, resides mainly in the inner mitochondrial membrane, and also associates with the outer mitochondrial membrane. LCA elicits an age-related remodeling of glycerophospholipid synthesis and movement within both mitochondrial membranes, thereby causing substantial changes in mitochondrial membrane lipidome and triggering major changes in mitochondrial size, number and morphology. In synergy, these changes in the membrane lipidome and morphology of mitochondria alter the age-related chronology of mitochondrial respiration, membrane potential, ATP synthesis and reactive oxygen species homeostasis. The LCA-driven alterations in the age-related dynamics of these vital mitochondrial processes extend yeast longevity. In sum, our findings suggest a mechanism underlying the ability of LCA to delay chronological aging in yeast by accumulating in both mitochondrial membranes and altering their glycerophospholipid compositions. We concluded that mitochondrial membrane lipidome plays an essential role in defining yeast longevity. PMID:23924582

Beach, Adam; Richard, Vincent R; Leonov, Anna; Burstein, Michelle T; Bourque, Simon D; Koupaki, Olivia; Juneau, Mylène; Feldman, Rachel; Iouk, Tatiana; Titorenko, Vladimir I

2013-07-01

202

Yeasts associated with Sardinian ewe's dairy products.  

PubMed

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. PMID:11589560

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

2001-09-19

203

Applicability of yeast genetics to neurologic disease.  

PubMed

As advances in gene mapping technology reveal genes associated with neurologic diseases, the need to identify a gene's normal function arises often. Experimental genetics is very useful in identifying a gene's function. It relies on model organisms both because it is not appropriate in humans, and because many processes are remarkably similar among eukaryotes. Many cellular processes have evolved once, and species differences are variations on a theme. Molecular genetic tools available in the yeast Saccharomyces cerevisiae provide a means to more rapidly reach an understanding of gene function, yielding substantial insight into the same process in humans. Yeast will never complain of headache or "spells," but do have expansions of trinucleotide repeats, prions, and other processes very much analogous to those underlying many neurologic diseases. In spite of the absence of a nervous system in yeast, yeast genetics has contributed substantial insight into neurologic diseases mechanisms. The real strength of yeast in studying human disease is in genetic analysis of gene function and in providing genetically powerful functional assays. Arch Neurol. 2000;57:1129-1134 PMID:10927792

Walberg, M W

2000-08-01

204

Influence of pesticides on yeasts colonizing leaves.  

PubMed

The effect of nine different pesticides on the growth of yeasts isolated from the leaves of fruit and forest trees was investigated. Four insecticides (with the active ingredients: thiacloprid, deltamethrin, lambdacyhalothrin, and thiamethoxam) and five fungicides (with the effective substances: bitertanol, kresoxim-methyl, mancozeb, trifloxystrobin, and cupric oxychloride) were tested. The concentrations of chemicals were those recommended by the manufacturers for the spraying of trees. The yeast strains isolated from the leaves of fruit trees were not sensitive to any of the insecticides. The majority of yeast strains isolated from the leaves of forest trees were either not sensitive or only to a small extent. While Rhodotorula mucilaginosa and Pichia anomala were not affected by any insecticide, the strains of Cryptococcus laurentii and Rhodotorula glutinis showed the highest sensitivity. The effects of fungicides on the growth of isolated yeasts were more substantial. The fungicide Dithane DG (mancozeb) completely inhibited the growth of all yeasts. All strains isolated from fruit tree leaves were more resistant to the tested fungicides than those isolated from the leaves of forest trees. The most resistant strains from the leaves of fruit trees belonged to the species Metschnikowia pulcherrima, Pichia anomala, and Saccharomyces cerevisiae, whereas Cryptococcus albidus and C. laurentii, originating from the leaves of forest trees, showed the highest sensitivity to fungicides. PMID:22351984

Vadkertiová, Renata; Sláviková, Elena

205

Mitochondrial membrane lipidome defines yeast longevity  

PubMed Central

Our studies revealed that lithocholic acid (LCA), a bile acid, is a potent anti-aging natural compound that in yeast cultured under longevity-extending caloric restriction (CR) conditions acts in synergy with CR to enable a significant further increase in chronological lifespan. Here, we investigate a mechanism underlying this robust longevity-extending effect of LCA under CR. We found that exogenously added LCA enters yeast cells, is sorted to mitochondria, resides mainly in the inner mitochondrial membrane, and also associates with the outer mitochondrial membrane. LCA elicits an age-related remodeling of glycerophospholipid synthesis and movement within both mitochondrial membranes, thereby causing substantial changes in mitochondrial membrane lipidome and triggering major changes in mitochondrial size, number and morphology. In synergy, these changes in the membrane lipidome and morphology of mitochondria alter the age-related chronology of mitochondrial respiration, membrane potential, ATP synthesis and reactive oxygen species homeostasis. The LCA-driven alterations in the age-related dynamics of these vital mitochondrial processes extend yeast longevity. In sum, our findings suggest a mechanism underlying the ability of LCA to delay chronological aging in yeast by accumulating in both mitochondrial membranes and altering their glycerophospholipid compositions. We concluded that mitochondrial membrane lipidome plays an essential role in defining yeast longevity.

Burstein, Michelle T.; Bourque, Simon D.; Koupaki, Olivia; Juneau, Mylene; Feldman, Rachel; Iouk, Tatiana; Titorenko, Vladimir I.

2013-01-01

206

[Molecular mechanisms of peroxisome biogenesis in yeasts].  

PubMed

Peroxisomes contain oxidases generating hydrogen peroxide, and catalase degrading this toxic compound. Another characteristic function of each eukaryotic peroxisome, from yeast to man, is fatty acid beta-oxidation. However, in peroxisomes a variety of other metabolic pathways are located. In fungi, peroxisomes contain enzymes involved in catabolism of unusual carbon and nitrogen sources (methanol, purines, D-amino acids, pipecolynic acid, sarcosine, glycolate, spermidine etc) as well as biosynthesis of lysine in yeasts and penicillin in mycelial fungi. Impairment of peroxisomal structure and functions causes many human disorders. The similar defects have been identified in yeast mutants defective in peroxisomal biogenesis. Peroxisomal biogenesis is actively studied during last two decades using uni- and multicellular model systems. It was observed that many aspects of peroxisomal biogenesis and proteins involved in this process display striking similarity between all eukaryotes, from yeasts to humans. Yeast is a convenient model system for this kind of research. Current review summarizes data on molecular events of peroxisomal biogenesis, functions of peroxine proteins, import of peroxisomal matrix and membrane proteins and on mechanisms of peroxisomedivision and inheritance. PMID:22642098

Sibirny?, A A

207

Rapid methods for identification of yeasts.  

PubMed Central

Opportunistic infections by yeasts have been implicated as one of the major causes of complications in the compromised patient. Rapid recognition and identification of these yeasts is essential for patient management, but conventional liquid medium methods for completing identification tests are cumbersome and time consuming. Rapid tests have been devised based on modifications of methods commonly used in bacteriology. These rapid methods included tests for carbohydrate and nitrate assimilation, fermentation, and urease production. These were compared with several current methods for accuracy of results, for time to final identification, and for economy of time and reagents. In addition, the usual tests for pseudogerm tube formation, for production of hyphae or pseudohyphae, and for growth temperatures were included. The rapid tests achieved 96% or better accuracy compared with expected results, and 46 species of yeasts were identified in 1 to 2 days compared with the 10 to 14 days required by conventional liquid culture methods. Images

Huppert, M; Harper, G; Sun, S H; Delanerolle, V

1975-01-01

208

Contribution of yeast models to neurodegeneration research.  

PubMed

As a model organism Saccharomyces cerevisiae has greatly contributed to our understanding of many fundamental aspects of cellular biology in higher eukaryotes. More recently, engineered yeast models developed to study endogenous or heterologous proteins that lay at the root of a given disease have become powerful tools for unraveling the molecular basis of complex human diseases like neurodegeneration. Additionally, with the possibility of performing target-directed large-scale screenings, yeast models have emerged as promising first-line approaches in the discovery process of novel therapeutic opportunities against these pathologies. In this paper, several yeast models that have contributed to the uncovering of the etiology and pathogenesis of several neurodegenerative diseases are described, including the most common forms of neurodegeneration worldwide, Alzheimer's, Parkinson's, and Huntington's diseases. Moreover, the potential input of these cell systems in the development of more effective therapies in neurodegeneration, through the identification of genetic and chemical suppressors, is also addressed. PMID:22910375

Pereira, Clara; Bessa, Cláudia; Soares, Joana; Leão, Mariana; Saraiva, Lucília

2012-07-15

209

Detection of Yeast Cells; Microfluidic Impedance Sensor  

NASA Astrophysics Data System (ADS)

A microelectromechanical system (MEMS) based biosensor was proposed for the rapid detection of pathogenic bacteria and contaminants that pose a threat to public health. In this study, experimental tests followed by finite element computer simulations were performed to selectively detect the quantity of yeast cells in a sample solution then was compared to a solution with no yeast cells. The impedance based biosensor detects the change in impedance caused by the presence of yeast cells between the electrodes integrated into microchannel walls that contain the target cells in a suspension medium. Microfluidic devices were fabricated by using two methods: traditional micromachining and photolithography for experimental purposes. An impedance analyzer was experimentally used for the measurement of the electrical impedance signals. Computer models based in COMSOL Multiphysics consisted of a long microchannel with two electrodes placed on opposite sides of the channel. Experimental data, simulation results and published data were compared and similar trends were found.

Hulea, Kelsey; Matune, Nicholas; Mabbott, Benjamin; Panta, Yogendra

2010-11-01

210

Cytotoxic Mechanism of Selenomethionine in Yeast*  

PubMed Central

Although selenium is an essential element, its excessive uptake is detrimental to living organisms. The significance of selenium for living organisms has been exploited for various purposes. However, the molecular basis of selenium toxicity is not completely understood. Here, we applied a capillary electrophoresis time-of-flight mass spectrometry-based metabolomics approach to analysis of yeast cells treated with selenomethionine. The data indicated that intracellular thiol compounds are significantly decreased, and diselenide and selenosulfide compounds are increased in selenomethionine-treated cells. The growth defect induced by selenomethionine was recovered by extracellular addition of cysteine and by genetic modification of yeast cells that have an additional de novo synthetic pathway for cysteine. Because cysteine is an intermediate of thiol compounds, these results suggested that the loss of a reduced form of thiol compounds due to selenomethionine causes a growth defect of yeast cells.

Kitajima, Toshihiko; Jigami, Yoshifumi; Chiba, Yasunori

2012-01-01

211

Isolation of the yeast nuclear pore complex  

PubMed Central

Nuclear pore complexes (NPCs) have been isolated from the yeast Saccharomyces. Negative stain electron microscopy of the isolated NPCs and subsequent image reconstruction revealed the octagonal symmetry and many of the ultrastructural features characteristic of vertebrate NPCs. The overall dimensions of the yeast NPC, both in its isolated form as well as in situ, are smaller than its vertebrate counterpart. However, the diameter of the central structures are similar. The isolated yeast NPC has a sedimentation coefficient of approximately 310 S and an M(r) of approximately 66 MD. It retains all but one of the eight known NPC proteins. In addition it contains as many as 80 uncharacterized proteins that are candidate NPC proteins.

1993-01-01

212

Predicting the Fission Yeast Protein Interaction Network  

PubMed Central

A systems-level understanding of biological processes and information flow requires the mapping of cellular component interactions, among which protein–protein interactions are particularly important. Fission yeast (Schizosaccharomyces pombe) is a valuable model organism for which no systematic protein-interaction data are available. We exploited gene and protein properties, global genome regulation datasets, and conservation of interactions between budding and fission yeast to predict fission yeast protein interactions in silico. We have extensively tested our method in three ways: first, by predicting with 70–80% accuracy a selected high-confidence test set; second, by recapitulating interactions between members of the well-characterized SAGA co-activator complex; and third, by verifying predicted interactions of the Cbf11 transcription factor using mass spectrometry of TAP-purified protein complexes. Given the importance of the pathway in cell physiology and human disease, we explore the predicted sub-networks centered on the Tor1/2 kinases. Moreover, we predict the histidine kinases Mak1/2/3 to be vital hubs in the fission yeast stress response network, and we suggest interactors of argonaute 1, the principal component of the siRNA-mediated gene silencing pathway, lost in budding yeast but preserved in S. pombe. Of the new high-quality interactions that were discovered after we started this work, 73% were found in our predictions. Even though any predicted interactome is imperfect, the protein network presented here can provide a valuable basis to explore biological processes and to guide wet-lab experiments in fission yeast and beyond. Our predicted protein interactions are freely available through PInt, an online resource on our website (www.bahlerlab.info/PInt).

Pancaldi, Vera; Sarac, Omer S.; Rallis, Charalampos; McLean, Janel R.; Prevorovsky, Martin; Gould, Kathleen; Beyer, Andreas; Bahler, Jurg

2012-01-01

213

Laboratory evolution of copper tolerant yeast strains  

PubMed Central

Background Yeast strains endowed with robustness towards copper and/or enriched in intracellular Cu might find application in biotechnology processes, among others in the production of functional foods. Moreover, they can contribute to the study of human diseases related to impairments of copper metabolism. In this study, we investigated the molecular and physiological factors that confer copper tolerance to strains of baker's yeasts. Results We characterized the effects elicited in natural strains of Candida humilis and Saccharomyces cerevisiae by the exposure to copper in the culture broth. We observed that, whereas the growth of Saccharomyces cells was inhibited already at low Cu concentration, C. humilis was naturally robust and tolerated up to 1 g · L-1 CuSO4 in the medium. This resistant strain accumulated over 7 mg of Cu per gram of biomass and escaped severe oxidative stress thanks to high constitutive levels of superoxide dismutase and catalase. Both yeasts were then "evolved" to obtain hyper-resistant cells able to proliferate in high copper medium. While in S. cerevisiae the evolution of robustness towards Cu was paralleled by the increase of antioxidative enzymes, these same activities decreased in evolved hyper-resistant Candida cells. We also characterized in some detail changes in the profile of copper binding proteins, that appeared to be modified by evolution but, again, in a different way in the two yeasts. Conclusions Following evolution, both Candida and Saccharomyces cells were able to proliferate up to 2.5 g · L-1 CuSO4 and to accumulate high amounts of intracellular copper. The comparison of yeasts differing in their robustness, allowed highlighting physiological and molecular determinants of natural and acquired copper tolerance. We observed that different mechanisms contribute to confer metal tolerance: the control of copper uptake, changes in the levels of enzymes involved in oxidative stress response and changes in the copper-binding proteome. However, copper elicits different physiological and molecular reactions in yeasts with different backgrounds.

2012-01-01

214

Altered transcription in yeast expressing expanded polyglutamine  

PubMed Central

Expanded polyglutamine tracts are responsible for at least eight fatal neurodegenerative diseases. In mouse models, proteins with expanded polyglutamine cause transcriptional dysregulation before onset of symptoms, suggesting that this dysregulation may be an early event in polyglutamine pathogenesis. Transcriptional dysregulation and cellular toxicity may be due to interaction between expanded polyglutamine and the histone acetyltransferase CREB-binding protein. To determine whether polyglutamine-mediated transcriptional dysregulation occurs in yeast, we expressed polyglutamine tracts in Saccharomyces cerevisiae. Gene expression profiles were determined for strains expressing either a cytoplasmic or nuclear protein with 23 or 75 glutamines, and these profiles were compared to existing profiles of mutant yeast strains. Transcriptional induction of genes encoding chaperones and heat-shock factors was caused by expression of expanded polyglutamine in either the nucleus or cytoplasm. Transcriptional repression was most prominent in yeast expressing nuclear expanded polyglutamine and was similar to profiles of yeast strains deleted for components of the histone acetyltransferase complex Spt/Ada/Gcn5 acetyltransferase (SAGA). The promoter from one affected gene (PHO84) was repressed by expanded polyglutamine in a reporter gene assay, and this effect was mitigated by the histone deacetylase inhibitor, Trichostatin A. Consistent with an effect on SAGA, nuclear expanded polyglutamine enhanced the toxicity of a deletion in the SAGA component SPT3. Thus, an early component of polyglutamine toxicity, transcriptional dysregulation, is conserved in yeast and is pharmacologically antagonized by a histone deacetylase inhibitor. These results suggest a therapeutic approach for treatment of polyglutamine diseases and provide the potential for yeast-based screens for agents that reverse polyglutamine toxicity.

Hughes, Robert E.; Lo, Russell S.; Davis, Colleen; Strand, Andrew D.; Neal, Cassandra L.; Olson, James M.; Fields, Stanley

2001-01-01

215

[The yeast biofilm in human medicine].  

PubMed

In recent years, the role of Candida yeasts as causative agents of nosocomial infections has increased. One of the important virulence factors contributing to the development of such infections is biofilm production. This virulence factor enables yeast to colonize both native surfaces and artificial implants. The most common sources of infection are patients themselves, in particular the gastrointestinal tract and skin. The vectors of exogenous yeast infections are predominantly the hands of the health personnel and contaminated medical instruments. The adhesion of yeasts to the implant surfaces is determined both by implant surface and yeast characteristics. This is followed by proliferation and production of microcolonies and extracellular matrix. The final biofilm structure is also influenced by the production of hyphae and pseudohyphae. The entire process of biofilm production is controlled by numerous regulatory systems, with the key role being played by the quorum sensing system. Like the adhered bacterial cultures, candidas growing in the form of a biofilm are highly resistant to antimicrobial therapy. Resistance of yeast biofilms to antifungals is a complex process with multiple contributing factors. These are especially increased gene expression (e.g. genes encoding the so called multidrug efflux pumps), limited penetration of substances through the extracellular matrix, inhibited cell growth and altered microenvironment in deeper biofilm layers. The concentrations of antifungals able to effectively affect the biofilm cells exceed, by several orders of magnitude, the values of conventionally determined MICs. High biofilm resistance results in ineffective antifungal therapy of biofilm infections. Therefore, if possible, the colonized implant should be removed. Conservative therapy should involve antifungals with a proven effect on the biofilm (e.g. caspofungin). The most effective measure in fighting biofilm infections is prevention, especially adhering to aseptic techniques when manipulating with implants and their correct maintenance. PMID:17929219

R?zicka, Filip; Holá, Veronika; Votava, Miroslav

2007-08-01

216

Male Yeast Infection: Can I Get It from My Girlfriend?  

MedlinePLUS

Male yeast infection: Can I get it from my girlfriend? Basics Reprints A single copy of this article may be reprinted for personal, noncommercial use only. Male yeast infection: Can I get it from my girlfriend? ...

217

BAM Media M182: Malt Extract Agar - (Yeasts and Molds) ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... BAM Media M182: Malt Extract Agar - (Yeasts and Molds) (MEAYM). January 2001. ... M182 Malt Extract Agar for Yeasts and Molds (MEAYM). ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

218

Factors Determining Translational Efficiency of mRNA in Yeast.  

National Technical Information Service (NTIS)

Killer virus of Saccharomyces cerevisiae is a cytoplasmically-inherited virus that confers on persistently-infected yeast cells the ability to secrete a protein toxin which kills uninfected yeast cells but to which infected cells, denoted killers, are res...

M. J. Leibowitz F. P. Barbone D. E. Georgopoulos

1991-01-01

219

21 CFR 172.381 - Vitamin D2 bakers yeast.  

Code of Federal Regulations, 2013 CFR

...prescribed conditions: (a) Vitamin D2 bakers yeast is the substance produced by exposing bakers yeast (Saccharomyces cerevisiae ) to ultraviolet light, resulting in the photochemical conversion of endogenous ergosterol in bakers...

2013-04-01

220

YEASTS FROM THE NORTH SEA AND AMOCO CADIZ OIL  

EPA Science Inventory

The species and densities of yeasts isolated from North Sea waters before and after the production of oil were compared. Debaryomyces hansenii was the predominant species, but after oil production, Candida guillieromondii, a hydrocarbonoclastic yeast, was more commonly isolated a...

221

BAM Media M151: Trypticase-Peptone-Glucose-Yeast Extract ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... BAM Media M151: Trypticase-Peptone-Glucose-Yeast Extract Broth (TPGY). ... M151 Trypticase-Peptone-Glucose-Yeast Extract Broth (TPGY). ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

222

Mitochondrial Network Size Scaling in Budding Yeast**  

PubMed Central

Mitochondria must grow with the growing cell to ensure proper cellular physiology and inheritance upon division. We measured the physical size of mitochondrial networks in budding yeast and found that mitochondrial network size increased with increasing cell size and that this scaling relation occurred primarily in the bud. The mitochondria to cell size ratio continually decreased in aging mothers over successive generations. However, regardless of mother age or mitochondrial content, all buds attained the same average ratio. Thus, yeast populations achieve a stable scaling relation between mitochondrial content and cell size despite asymmetry in inheritance.

Rafelski, Susanne M.; Viana, Matheus P.; Zhang, Yi; Chan, Yee-Hung M.; Thorn, Kurt S.; Yam, Phoebe; Fung, Jennifer C.; Li, Hao; Costa, Luciano da F.; Marshall, Wallace F.

2013-01-01

223

Understanding cytokinesis: lessons from fission yeast  

PubMed Central

For decades after the discovery that a contractile ring made of actin filaments and myosin II produces the force to constrict the cleavage furrow of animal cells, the complexity of cytokinesis has slowed progress in understanding the mechanism. Mechanistic insights, however, have been obtained by genetic, biochemical, microscopic and mathematical modelling approaches in the fission yeast Schizosaccharomyces pombe. Many features that have been identified in fission yeast are probably shared with animal cells, as both inherited many cytokinesis genes from their common ancestor about one billion years ago.

Pollard, Thomas D.; Wu, Jian-Qiu

2010-01-01

224

Expression of human. alpha. -fetoprotein in yeast  

SciTech Connect

Human {alpha}-fetoprotein (AFP) was expressed in Saccharomyces cerevisiae, with a plasmid containing the cDNA sequence for human AFP fused with the rat AFP signal peptide. The recombinant AFP was purified from the yeast lysate by DEAE-cellulose and immunoaffinity chromatography. The amino acid composition and the molecular weight of the recombinant AFP were similar to those of hepatoma AFP. N-terminal amino acids sequence analysis indicated that the signal peptide had been processed. The recombinant and hepatoma AFP reacted identically in Ouchterlony immunodiffusion and radioimmunoassay tests. These observations indicated that the yeast recombinant protein had the properties of native AFP.

Yamamoto, Ritsu; Sakamoto, Takashi; Nishi, Shinzo; Sakai, Masaharu; Morinaga, Tomonori; Tamaoki, Taiki (Hokkaido Univ. School of Medicine (Japan) Univ. of Calgary, Alberta (Canada))

1990-01-01

225

Biogenesis of extracellular vesicles in yeast  

PubMed Central

The cellular events required for unconventional protein secretion in eukaryotic pathogens are beginning to be revealed. In fungi, extracellular release of proteins involves passage through the cell wall by mechanisms that are poorly understood. In recent years, several studies demonstrated that yeast cells produce vesicles that traverse the cell wall to release a wide range of cellular components into the extracellular space. These studies suggested that extracellular vesicle release involves components of both conventional and unconventional secretory pathways, although the precise mechanisms required for this process are still unknown. We discuss here cellular events that are candidates for regulating this interesting but elusive event in the biology of yeast cells.

Oliveira, Debora L; Nakayasu, Ernesto S; Joffe, Luna S; Guimaraes, Allan J; Sobreira, Tiago JP; Nosanchuk, Joshua D; Cordero, Radames JB; Frases, Susana; Casadevall, Arturo; Almeida, Igor C; Nimrichter, Leonardo

2010-01-01

226

Three's company: The fission yeast actin cytoskeleton  

PubMed Central

How the actin cytoskeleton assembles into different structures to drive diverse cellular processes is a fundamental cell biological question. In addition to orchestrating the appropriate combination of regulators and actin-binding proteins, different actin-based structures must insulate themselves from one another to maintain specificity within a crowded cytoplasm. Actin specification is particularly vexing in complex eukaryotes where a multitude of protein isoforms and actin structures operate within the same cell. Fission yeast Schizosaccharomyces pombe possesses a single actin isoform that functions in three distinct structures throughout the cell cycle. In this review, we explore recent studies in fission yeast that help unravel how different actin structures operate in cells.

Kovar, David R.; Sirotkin, Vladimir; Lord, Matthew

2010-01-01

227

RNA Isolation from Yeast Using Silica Matrices  

PubMed Central

RNA isolation from yeast is complicated by the need to initially break the cell wall. While this can be accomplished by glass bead disruption or enzyme treatment, these approaches result in DNA contamination and/or the need for incubation periods. We have developed a protocol for the isolation of RNA samples from yeast that minimizes degradation by RNases and incorporates two purification steps: acid phenol extraction and binding to a silica matrix. The procedure requires no precipitation steps, facilitating automation, and can be completed in less than 90 min. The RNA quality is ideal for microarray analysis.

Mutiu, A. Irina; Brandl, Christopher J.

2005-01-01

228

Dynamic and Elongation Rheology of Yeasted Bread Doughs  

Microsoft Academic Search

Cereal Chem. 79(6):874-879 The rheology of yeasted bread doughs is a little-studied field despite yeast's importance in developing bread structure. A method of thermally inactivating the yeast within mixed bread doughs was developed to overcome the difficulty of yeast fermenting during rheological measure- ments. Sample stabilization by preshearing of dough samples at a stress amplitude of 1 Pa at 1

M. P. Newberry; N. Phan-Thien; O. R. Larroque; R. I. Tanner; N. G. Larsen

2002-01-01

229

Fermentation of maltotriose by brewer's and baker's yeasts  

Microsoft Academic Search

Two brewer's yeasts and one baker's yeast grew with =95% (w\\/w) pure maltotriose as carbon source in the presence of antimycin A to block respiration. Biomass yields (0.15 and 0.24 g dry yeast g-1 sugar, respectively, with and without antimycin A) were similar for growth on maltose and maltotriose, and yields of ethanol were 80% of stoichiometric. Yeasts harvested during

John Londesborough

2001-01-01

230

Use of fluorescence spectroscopy to differentiate yeast and bacterial cells  

Microsoft Academic Search

This study focuses on the characterization of bacterial and yeast species through their autofluorescence spectra. Lactic acid bacteria (Lactobacillus sp.), and yeast (Saccharomyces sp.) were cultured under controlled conditions and studied for variations in their autofluorescence, particularly in the area representative of tryptophan residues of proteins. The emission and excitation spectra clearly reveal that bacterial and yeast species can be

Hemant Bhatta; Ewa M. Goldys; Robert P. Learmonth

2006-01-01

231

Population genomic analysis of outcrossing and recombination in yeast  

Microsoft Academic Search

The budding yeast Saccharomyces cerevisiae has been used by humans for millennia to make wine, beer and bread. More recently, it became a key model organism for studies of eukaryotic biology and for genomic analysis. However, relatively little is known about the natural lifestyle and population genetics of yeast. One major question is whether genetically diverse yeast strains mate and

Douglas M Ruderfer; Stephen C Pratt; Hannah S Seidel; Leonid Kruglyak

2006-01-01

232

Heat Stress-Induced Life Span Extension in Yeast  

Microsoft Academic Search

The yeastSaccharomyces cerevisiaehas a limited life span that can be measured by the number of times individual cells divide. Several genetic manipulations have been shown to prolong the yeast life span. However, environmental effects that extend longevity have been largely ignored. We have found that mild, nonlethal heat stress extended yeast life span when it was administered transiently early in

Silvian Shama; Chi-Yung Lai; Jill M. Antoniazzi; James C. Jiang; S. Michal Jazwinski

1998-01-01

233

Production of lipid compounds in the yeast Saccharomyces cerevisiae  

Microsoft Academic Search

This review describes progress using the yeast Saccharomyces cerevisiae as a model organism for the fast and efficient analysis of genes and enzyme activities involved in the lipid biosynthetic pathways of several donor organisms. Furthermore, we assess the impact of baker's yeast on the production of novel, high-value lipid compounds. Yeast can be genetically modified to produce selected substances in

M. Veen; C. Lang

2004-01-01

234

21 CFR 172.590 - Yeast-malt sprout extract.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2010-01-01 2009-04-01 true Yeast-malt sprout extract. 172.590 Section 172...Flavoring Agents and Related Substances § 172.590 Yeast-malt sprout extract. Yeast-malt sprout extract, as described in this...

2010-01-01

235

GENE ENGINEERING OF YEASTS FOR THE DEGRADATION OF HAZARDOUS WASTE  

EPA Science Inventory

The research examined the structure and function of cytochrome P-450 genes in yeast as a model for gene engineering such as eukaryotic P-450 enzymes for biodegradation of hazardous waste by yeasts. Saccharomyces cerevisiae and Candida tropicalis are two yeasts known to produce ma...

236

Yeasts used to delay browning in white wines  

Microsoft Academic Search

Commercial white wines of the Sherry type were subjected to accelerated browning at 35 °C in the absence and presence of yeasts at concentrations of 1, 1.5 and 2 g\\/l. Based on the results, the yeasts delayed browning in the wines, measured in terms of the absorbance at 420 nm, the effect increasing with increase in the yeast concentration. The

Azahara Lopez-Toledano; Manuel Mayen; Julieta Merida; Manuel Medina

2006-01-01

237

Yeast identification in floral nectar of Mimulus aurantiacus (Invited)  

Microsoft Academic Search

Nectar is such a sugar-rich resource that serves as a natural habitat in which microbes thrive. As a result, yeasts arrive to nectar on the bodies of pollinators such as hummingbirds and bees. Yeasts use the sugar in nectar for their own needs when introduced. This research focuses on the identification of different types of yeast that are found in

C. Kyauk; M. Belisle; T. Fukami

2009-01-01

238

Global Gene Expression Analysis of Yeast Cells during Sake Brewing  

Microsoft Academic Search

During the process of brewing Japanese sake, rice starch is saccharified by enzymes produced by koji (Aspergillus oryzae), and the resultant glucose is fermented to ethanol by sake yeast (Saccharomyces cerevisiae). This process allows a highly con- densed mash to be made without accumulation of high levels of sugars, which inhibit yeast cell growth and ethanol fermenta- tion. Thus, yeast

Hong Wu; Xiaohong Zheng; Yoshio Araki; Hiroshi Sahara; Hiroshi Takagi; Hitoshi Shimoi

2006-01-01

239

21 CFR 172.590 - Yeast-malt sprout extract.  

Code of Federal Regulations, 2013 CFR

... 3 2013-04-01 2013-04-01 false Yeast-malt sprout extract. 172.590 Section 172...Flavoring Agents and Related Substances § 172.590 Yeast-malt sprout extract. Yeast-malt sprout extract, as described in this...

2013-04-01

240

21 CFR 573.750 - Pichia pastoris dried yeast.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Pichia pastoris dried yeast. 573.750 Section 573.750 Food...Listing § 573.750 Pichia pastoris dried yeast. (a) Identity . The food additive Pichia pastoris dried yeast may be used in feed formulations...

2013-04-01

241

Ethanol production from xylose by enzymic isomerization and yeast fermentation  

Microsoft Academic Search

Repetitive enzymic isomerization of xylose followed by yeast fermentation of xylulose, and simultaneous enzymic isomerization and yeast fermentation were proven to be methods capable of converting xylose to ethanol. The fermentation product, ethanol, xylitol, or glycerol, has little inhibitory or deactivation effect on the activity of isomerase. In a comparison of the ability of yeasts to ferment xylulose to ethanol,

L. C. Chiang; H. Y. Hsiao; P. P. Ueng; L. F. Chen; G. T. Tsao

1981-01-01

242

Cycloheximide resistance as marker for monitoring yeasts in wine fermentations  

Microsoft Academic Search

When selected yeast strains are used in wine-making, it is necessary to ensure that the fermentation process is really conducted by the inoculated yeast. Saccharomyces cerevisiae spontaneous mutants resistant to cycloheximide (cyhr) were isolated from industrial strains. The mutations did not affect the fermentation kinetics, the quality of the wines, or the viability of active dry yeast made with the

F Pérez; J. A Regodón; M. E Valdés; C De Miguel; M Ram??rez

2000-01-01

243

Fission yeast and other yeasts as emergent models to unravel cellular aging in eukaryotes.  

PubMed

In the past years, simple organisms such as yeasts and worms have contributed a great deal to aging research. Studies pioneered in Saccharomyces cerevisiae were useful to elucidate a significant number of molecular mechanisms underlying cellular aging and to discover novel longevity genes. Importantly, these genes proved many times to be conserved in multicellular eukaryotes. Consequently, such discovery approaches are being extended to other yeast models, such as Schizosaccharomyces pombe, Candida albicans, Kluyveromyces lactis, and Cryptococcus neoformans. In fission yeast, researchers have found links between asymmetrical cell division and nutrient signaling pathways with aging. In this review, we discuss the state of knowledge on the mechanisms controlling both replicative and chronological aging in S pombe and the other emergent yeast models. PMID:19875745

Roux, Antoine E; Chartrand, Pascal; Ferbeyre, Gerardo; Rokeach, Luis A

2009-10-29

244

Qualitative yeast enzyme analysis by electrophoresis  

Microsoft Academic Search

Baker's yeast (Saccharomyces cerevisiae) was cultivated under different intensities of aeration on glucose and on ethanol. Seventeen enzymes of the Embden-Meyerhof pathway and the TCA cycle or related reactions were then assayed by starch gel electrophoresis. There were both qualitative and quantitative differences in many enzymes, most notably in glyceraldehyde-3-phosphate dehydrogenase, alcohol dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase, and fumarase. Enzyme

Anssi Saura; Juhani Lokki; Erkki Oura; Heikki Suomalainen

1979-01-01

245

Cell cycle control of yeast filamentous growth  

Microsoft Academic Search

Great progress has been made toward dissecting the signal transduction pathways and transcriptional outputs regulating yeast pseudohyphal growth. However, the mechanism underlying polarized morphogenesis in filamentous growth remains unclear. A synthesis of the data suggests that the ultimate target of these pathways is to repress the activity of the mitotic cyclin Clb2 as an antagonist of polarized growth. Here, we

Diego Rua; Brian T Tobe; Stephen J Kron

2001-01-01

246

Dielectric analysis of yeast cell growth  

Microsoft Academic Search

On-line dielectric measurements of yeast cells (Saccharomyces cerevisiae) growing in suspension culture were made over a frequency range from 0.1 to 100 MHz. The amplitude of the dielectric dispersion centered at about 1 MHz increased exponentially with cultivation time in the logarithmic growth phase and then remained constant in the stationary phase. This result clearly indicates that the mass and

Koji Asami; Takeshi Yonezawa

1995-01-01

247

Boron Stimulates Yeast (Saccharomyces cerevisiae) Growth  

Microsoft Academic Search

Boron is required for the growth of vascular plants and embryonic development in fish. The molecular basis of boron's essentiality, however, remains unknown for both. The objective of this study was to determine whether yeast (Saccharomyces cerevisiae) could be used as a model for the evaluation of intracellular boron traffick- ing. Three experiments were conducted to assess the ef- fect

A. Bennett; R. I. Rowe; N. Soch; C. D. Eckhert

248

Yields of yeast growth on starch  

Microsoft Academic Search

Summary A survey was made of 81 starch-assimilating yeasts, representing 59 species and varieties, with respect to their capacity for the direct conversion of starch into SCP. The extent of starch conversion by the native amylases of the strains during exponential growth, expressed as yield on starch (final amount of dry biomass formed per unit mass of starch originally supplied),

I. Spencer-Martins; N. van Uden

1977-01-01

249

Transcription and Organization of Yeast Mitochondrial DNA.  

National Technical Information Service (NTIS)

The following topics are discussed: characterization of mtDNA transcripts including tRNA and messenger RNA; determination of the fraction of yeast mtDNA transcribed in vivo using mitochondrial RNA-DNA hybridization; analysis of hybridization with single s...

M. Rabinowitz S. Jakovcic N. Martin F. Hendler A. Halbreich

1976-01-01

250

Cellular functions of cardiolipin in yeast  

Microsoft Academic Search

Cardiolipin (CL), the signature lipid of mitochondria, plays a critical role in mitochondrial function and biogenesis. The availability of yeast mutants blocked in CL synthesis has facilitated studies of the biological role of this lipid. Perturbation of CL synthesis leads to growth defects not only during respiratory growth but also under conditions in which respiration is not essential. CL was

Amit S. Joshi; Jingming Zhou; Vishal M. Gohil; Shuliang Chen; Miriam L. Greenberg

2009-01-01

251

6 Oxidative stress responses in yeast  

Microsoft Academic Search

Yeast, and especially S. cerevisiae, is a unique eukaryotic model organism for studying oxidative stress and its cellular responses. S. cerevisiae has become a very powerful tool to decipher the complexity of these biologically important responses, because it offers the relative simplicity of a single celled eukaryotic organism that enables the combination and integration of genetic, biochemical, physico-chemical, cell biological,

Michel B. Toledano; Agnes Delaunay; Benoit Biteau; Daniel Spector; Dulce Azevedo

252

The economics of ribosome biosynthesis in yeast  

Microsoft Academic Search

In a rapidly growing yeast cell, 60% of total transcription is devoted to ribosomal RNA, and 50% of RNA polymerase II transcription and 90% of mRNA splicing are devoted to ribosomal proteins (RPs). Coordinate regulation of the ?150 rRNA genes and 137 RP genes that make such prodigious use of resources is essential for the economy of the cell. This

Jonathan R Warner

1999-01-01

253

Metal cation uptake by yeast: a review  

Microsoft Academic Search

This review addresses metal uptake specifically by yeast. Metal uptake may be passive, active or both, depending on the viability of the biomass, and is influenced by a number of environmental and experimental factors. Uptake is typically accompanied by a degree of ion exchange and, under certain conditions, may be enhanced by the addition of an energy source, Intracellularly accumulated

K. J. Blackwell; I. Singleton; J. M. Tobin

1995-01-01

254

The Nutritional Tests in Yeast Systematics  

Microsoft Academic Search

SUMMARY Valuable information, which could be obtained from the nutritional tests used to classify yeasts, is lost in two ways. (i) Tests of ability to grow on organic com- pounds are only done semi-aerobically; this makes many results difficult to interpret. (ii) Many results remain unpublished because information on individual strains is condensed into a description of the species. Suggestions

J. A. BARNETT

1977-01-01

255

Mass spectrometer monitoring of a yeast fermentation  

Microsoft Academic Search

A flow-through membrane based mass spectrometer is employed for the purpose of monitoring and controlling fermentations. A sample stream in either the gaseous or liquid phase can be continuously passed through the interface, with a fraction of the volatile compounds transferred into the spectrometer. For the monitoring of alcohol fermentation employing bakers' yeast, a water-saturated carrier gas (Nâ) is bubbled

J. C. Weaver; C. R. Perley; C. L. Cooney

1980-01-01

256

Phosphorylation site on yeast pyruvate dehydrogenase complex  

SciTech Connect

The pyruvate dehydrogenase complex was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). Yeast cells were disrupted in a Manton-Gaulin laboratory homogenizer. The pyruvate dehydrogenase complex was purified by fractionation with polyethylene glycol, isoelectric precipitation, ultracentrifugation and chromatography on hydroxylapatite. Final purification of the yeast pyruvate dehydrogenase complex was achieved by cation-exchange high pressure liquid chromatography (HPLC). No endogenous pyruvate dehydrogenase kinase activity was detected during the purification. However, the yeast pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. Tryptic digestion of the /sup 32/P-labeled complex yielded a single phosphopeptide which was purified to homogeniety. The tryptic digest was subjected to chromatography on a C-18 reverse phase HPLC column with a linear gradient of acetonitrile. Radioactive fractions were pooled, concentrated, and subjected to anion-exchange HPLC. The column was developed with a linear gradient of ammonium acetate. Final purification of the phosphopeptide was achieved by chromatography on a C-18 reverse phase HPLC column developed with a linear gradient of acetonitrile. The amino acid sequence of the homogeneous peptide was determined by manual modified Edman degradation.

Uhlinger, D.J.

1986-01-01

257

Potential therapeutic effect of yeast killer toxin  

Microsoft Academic Search

Experimental infections were produced in guinea pigs, rabbits and dogs with lesions similar to those seen in human seborrheic dermatitis and otitis externa by cutaneous application of cultures of Malassezia furfur and M. pachydermatis. Infected animals were treated by topical application of a concentrated yeast killer toxin (Hansenula anomala UCSC 25F). Clinical recovery as well as negative mycological test cultures

Luciano Polonelli; Rodolfo Lorenzini; Flavia De Bernardis; Giulia Morace

1986-01-01

258

Pathways of DNA Repair in Yeast.  

National Technical Information Service (NTIS)

The RAD1 excision-repair pathway of yeast consists of three additional genes, RAD7, RAD14 and MMS19, all of which are shown to be defective in excision of pyrimidine dimers. In addition, two genes, MMS3 and CDC8 are discussed in terms of their effect on u...

L. Prakash S. Prakash

1978-01-01

259

Continuous ethanol production by immobilized yeast reactor  

Microsoft Academic Search

Saccharomyces cerevisiae yeast immobilized in calcium alginate gel beads was employed in packed-bed column reactors for continuous ethanol production from glucose or cane molasses, and for beer fermentation from barley malt wort. With properly balanced nutrient content or periodical regeneration of cells by nutrient addition and aeration, ethanol production could be maintained for several months. About 7 percent (w\\/v) ethanol

Yu-Yen Linko; P. Linko

1981-01-01

260

Chromosome Dynamics in the Yeast Interphase Nucleus  

Microsoft Academic Search

Little is known about the dynamics of chromosomes in interphase nuclei. By tagging four chromosomal regions with a green fluorescent protein fusion to lac repressor, we monitored the movement and subnuclear position of specific sites in the yeast genome, sampling at short time intervals. We found that early and late origins of replication are highly mobile in G1 phase, frequently

Patrick Heun; Thierry Laroche; Kenji Shimada; Patrick Furrer; Susan M. Gasser

2001-01-01

261

Ethanol-induced water stress in yeast  

Microsoft Academic Search

This review considers the effect of ethanol-induced water stress on yeast metabolism and integrity. Ethanol causes water stress by lowering water activity (aw) and thereby interferes with hydrogen bonding within and between hydrated cell components, ultimately disrupting enzyme and membrane structure and function. The impact of ethanol on the energetic status of water is considered in relation to cell metabolism.

John E. Hallsworth

1998-01-01

262

Intracellular accumulation of ethanol in yeast  

Microsoft Academic Search

Ethanol produced in the course of a batch fermentation by Saccharomyces cerevisiae or added from the outside, affects adversely the specific rate of growth of the yeast population, its viability, its specific rate of fermentation, and the specific rates of the uptake of sugar and amino acids. The underlying mechanisms are many and include irreversible denaturation and hyperbolic noncompetitive inhibition

V. Loueiro; H. G. Ferreira

1983-01-01

263

Yeast mutants resistant to ethidium bromide  

Microsoft Academic Search

Yeast mutants resistant to ethidium bromide have been isolated among sensitive grande cells (?+) for their ability to grow on glycerol in the presence of the dye. Mutant cells are also resistant to acriflavin and do not yield petites (?-) when grown on galactose with the mutagen. Genetic analysis reveals that resistance to ethidium bromide is controlled by a cytoplasmic

M. Gouhier; J. C. Mounolou

1973-01-01

264

Assembling large DNA segments in yeast.  

PubMed

As described in a different chapter in this volume, the uracil-specific excision reaction (USER) fusion method can be used to assemble multiple small DNA fragments (?0.75-kb size) into larger 3-kb DNA segments both in vitro and in vivo (in Escherichia coli). However, in order to assemble an entire synthetic yeast genome (Sc2.0 project), we need to be able to assemble these 3-kb pieces into larger DNA segments or chromosome-sized fragments. This assembly into larger DNA segments is carried out in vivo, using homologous recombination in yeast. We have successfully used this approach to assemble a 40-kb chromosome piece in the yeast Saccharomyces cerevisiae. A lithium acetate (LiOAc) protocol using equimolar amount of overlapping smaller fragments was employed to transform yeast. In this chapter, we describe the assembly of 3-kb fragments with an overlap of one building block (?750 base pairs) into a 40-kb DNA piece. PMID:22328431

Muller, Héloïse; Annaluru, Narayana; Schwerzmann, Joy Wu; Richardson, Sarah M; Dymond, Jessica S; Cooper, Eric M; Bader, Joel S; Boeke, Jef D; Chandrasegaran, Srinivasan

2012-01-01

265

Glucose-Induced Acidification in Yeast Cultures  

ERIC Educational Resources Information Center

|We present an investigation (for A-level biology students and equivalent) into the mechanism of glucose-induced extracellular acidification in unbuffered yeast suspensions. The investigation is designed to enhance understanding of aspects of the A-level curriculum that relate to the phenomenon (notably glucose catabolism) and to develop key…

Myers, Alan; Bourn, Julia; Pool, Brynne

2005-01-01

266

Conflict between Noise and Plasticity in Yeast  

Microsoft Academic Search

Gene expression responds to changes in conditions but also stochastically among individuals. In budding yeast, both expression responsiveness across conditions (“plasticity”) and cell-to-cell variation (“noise”) have been quantified for thousands of genes and found to correlate across genes. It has been argued therefore that noise and plasticity may be strongly coupled and mechanistically linked. This is consistent with some theoretical

Ben Lehner

2010-01-01

267

Selenium yeast: Composition, quality, analysis, and safety  

Microsoft Academic Search

Selenium yeast, produced by growing select strains of Saccharomyces cerevisiae in Se-rich media, is a recognized source of organic food-form Se, but the determination of its exact composition with respect to the Se species present produced conflicting results. Improved methods of analysis have since revealed it to contain 90+ % of its Se in the form of selenomethionine, the principal

G. N. Schrauzer

2006-01-01

268

An Engineered Yeast Efficiently Secreting Penicillin  

PubMed Central

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

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

2009-01-01

269

Copper transport in non-growing yeast  

SciTech Connect

The mandatory role of copper (Cu) proteins in cell metabolism and the speculation that Cu influences the production of porphyrins and hemoproteins prompted an examination of the regulatory features of, and the process by which Cu is taken up by yeast. Saccharomyces Cerevisiae was grown on glucose minimal media in the absence of added Cu at 29/sup 0/C, 200 rpm for 48-72 hrs. Cells were harvested and washed by centrifugation and resuspended at standardized mg dry weight/ml. The yeast was exposed to Cu under a variety of experimental conditions in 10 ml volume containing approximately 5 mg (dry wt.) yeast and Cu (0-10/sup -4/M). Reactions were stopped by microcentrifugation and Cu was determined, by difference, using atomic absorption spectrophotometry. The time course of Cu uptake reflected two phases; a rapid rate followed by a slow rate which varied according to conditions. Direct determination of Cu using washing (chelators) and ashing of washed yeast showed that the initial phase was indeed adsorption of Cu to cell exterior. While the relationship of adsorbed Cu to Cu uptake has not been evaluated the system nevertheless is being used for the determination of the effects of environmental factors (pH, (Cu), temperature, etc.) on the uptake process. Furthermore, this system provides a convenient method for characterizing the Cu-transport machinery in a static (non-growth) mode.

Turos, S.; Donahue, T.; Trent, C.; Connelly, J.L.

1986-05-01

270

Characterization of yeast strains for wine production  

Microsoft Academic Search

Sixteen yeast strains isolated from grapefruit (Citrus paradis), orange (Citrus sinensis) and pineapple (Ananas comosus) were characterized using standard microbiological procedures. The species were identified as Saccharomyces uvarum, S. cerevisiae, S. carlbergensis, and S. ellipsoideus. Their abilities for wine production were tested by using sugar and ethanol tolerance tests. The best biochemically active\\u000a strain, S. ellipsoideus, was used along with

R. N. Ndip; J.-F. K. T. Akoachere; L. L. Dopgima; L. M. Ndip

2001-01-01

271

Molecular Evolution of Minisatellites in Hemiascomycetous Yeasts  

Microsoft Academic Search

Minisatellites are DNA tandem repeats exhibiting size polymorphism among individuals of a population. This polymor- phism is generated by two different mechanisms, both in human and yeast cells, ''replication slippage'' during S-phase DNA synthesis and ''repair slippage'' associated to meiotic gene conversion. The Saccharomyces cerevisiae genome con- tains numerous natural minisatellites. They are located on all chromosomes without any obvious

Guy-Franck Richard; Bernard Dujon

2005-01-01

272

yApoptosis: yeast apoptosis database.  

PubMed

In the past few years, programmed cell death (PCD) has become a popular research area due to its fundamental aspects and its links to human diseases. Yeast has been used as a model for studying PCD, since the discovery of morphological markers of apoptotic cell death in yeast in 1997. Increasing knowledge in identification of components and molecular pathways created a need for organization of information. To meet the demands from the research community, we have developed a curated yeast apoptosis database, yApoptosis. The database structurally collects an extensively curated set of apoptosis, PCD and related genes, their genomic information, supporting literature and relevant external links. A web interface including necessary functions is provided to access and download the data. In addition, we included several networks where the apoptosis genes or proteins are involved, and present them graphically and interactively to facilitate rapid visualization. We also promote continuous inputs and curation by experts. yApoptosis is a highly specific resource for sharing information online, which supports researches and studies in the field of yeast apoptosis and cell death. Database URL: http://www.ycelldeath.com/yapoptosis/ PMID:24082050

Wanichthanarak, Kwanjeera; Cvijovic, Marija; Molt, Andrea; Petranovic, Dina

2013-09-29

273

yApoptosis: yeast apoptosis database  

PubMed Central

In the past few years, programmed cell death (PCD) has become a popular research area due to its fundamental aspects and its links to human diseases. Yeast has been used as a model for studying PCD, since the discovery of morphological markers of apoptotic cell death in yeast in 1997. Increasing knowledge in identification of components and molecular pathways created a need for organization of information. To meet the demands from the research community, we have developed a curated yeast apoptosis database, yApoptosis. The database structurally collects an extensively curated set of apoptosis, PCD and related genes, their genomic information, supporting literature and relevant external links. A web interface including necessary functions is provided to access and download the data. In addition, we included several networks where the apoptosis genes or proteins are involved, and present them graphically and interactively to facilitate rapid visualization. We also promote continuous inputs and curation by experts. yApoptosis is a highly specific resource for sharing information online, which supports researches and studies in the field of yeast apoptosis and cell death. Database URL: http://www.ycelldeath.com/yapoptosis/

Wanichthanarak, Kwanjeera; Cvijovic, Marija; Molt, Andrea; Petranovic, Dina

2013-01-01

274

A method for plasmid purification directly from yeast.  

PubMed

A rapid technique for purifying plasmids from yeast Saccharomyces cerevisiae is described that yields high-quality DNA suitable for bacterial transformation, yeast transformation, and direct DNA sequencing. The method requires only small culture volumes and proprietary bacterial plasmid miniprep kits that allow one to simultaneously prepare a large number of samples in a very short period of time while avoiding the use of toxic organic chemicals. Both yeast single-copy CEN/ARS and high-copy 2micro shuttle plasmids can be isolated using this method. This technique is useful for plasmid purification from yeast two-hybrid experiments as well as yeast genetics and molecular biology experiments. PMID:12137773

Singh, Madhu V; Weil, P Anthony

2002-08-01

275

Fractal analysis of yeast cell optical speckle  

NASA Astrophysics Data System (ADS)

Steady state laser light propagation in diffuse media such as biological cells generally provide bulk parameter information, such as the mean free path and absorption, via the transmission profile. The accompanying optical speckle can be analyzed as a random spatial data series and its fractal dimension can be used to further classify biological media that show similar mean free path and absorption properties, such as those obtained from a single population. A population of yeast cells can be separated into different portions by centrifuge, and microscope analysis can be used to provide the population statistics. Fractal analysis of the speckle suggests that lower fractal dimension is associated with higher cell packing density. The spatial intensity correlation revealed that the higher cell packing gives rise to higher refractive index. A calibration sample system that behaves similar as the yeast samples in fractal dimension, spatial intensity correlation and diffusion was selected. Porous silicate slabs with different refractive index values controlled by water content were used for system calibration. The porous glass as well as the yeast random spatial data series fractal dimension was found to depend on the imaging resolution. The fractal method was also applied to fission yeast single cell fluorescent data as well as aging yeast optical data; and consistency was demonstrated. It is concluded that fractal analysis can be a high sensitivity tool for relative comparison of cell structure but that additional diffusion measurements are necessary for determining the optimal image resolution. Practical application to dental plaque bio-film and cam-pill endoscope images was also demonstrated.

Flamholz, A.; Schneider, P. S.; Subramaniam, R.; Wong, P. K.; Lieberman, D. H.; Cheung, T. D.; Burgos, J.; Leon, K.; Romero, J.

2006-03-01

276

Molecular identification of yeasts associated with traditional Egyptian dairy products.  

PubMed

This study aimed to examine the diversity and ecology of yeasts associated with traditional Egyptian dairy products employing molecular techniques in yeast identification. A total of 120 samples of fresh and stored Domiati cheese, kariesh cheese, and "Matared" cream were collected from local markets and examined. Forty yeast isolates were cultured from these samples and identified using the restriction-fragment length polymorphism (RFLPs) of 5.8S-ITS rDNA region and sequencing of the domains D1 and D2 of the 26S rRNA gene. Yeasts were identified as Issatchenkia orientalis (13 isolates), Candida albicans (4 isolates), Clavispora lusitaniae (Candida lusitaniae) (9 isolates), Kodamaea ohmeri (Pichia ohmeri) (1 isolate), Kluyveromyces marxianus (6 isolates), and Candida catenulata (7 isolates). With the exception of C. lusitaniae, the D1/D2 26S rRNA gene sequences were 100% identical for the yeast isolates within the same species. Phylogenetic reconstruction of C. lusitaniae isolates grouped them into 3 distinguished clusters. Kariesh cheese was found to be the most diverse in its yeast floras and contained the highest total yeast count compared with other examined dairy products. This was linked to the acidic pH and lower salt content of this cheese, which favor the growth and survival of yeasts in foodstuffs. Stored Domiati cheese also contained diverse yeast species involving isolates of the pathogenic yeast C. albicans. This raises the possibility of dairy products being vehicles of transmission of pathogenic yeasts. PMID:19895478

El-Sharoud, W M; Belloch, C; Peris, D; Querol, A

2009-09-01

277

Inventions on baker's yeast strains and specialty ingredients.  

PubMed

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. PMID:20653532

Gélinas, Pierre

2009-06-01

278

International Specialised Symposium on Yeasts: ISSY25. Systems Biology of Yeasts from Models to Applications. Held in Hanasaari, Espoo, Finland on June 18-21, 2006.  

National Technical Information Service (NTIS)

The 25th International Specialized Symposium on Yeasts, ISSY25, dedicated to 'Yeast systems biology - from models to applications' is a symposium in a series organized by the members of the International Commission on Yeasts (ICY), an IUMS organization. T...

A. Kuokka M. Penttila

2006-01-01

279

Prion formation by a yeast GLFG nucleoporin  

PubMed Central

The self-assembly of proteins into higher order structures is both central to normal biology and a dominant force in disease. Certain glutamine/asparagine (Q/N)-rich proteins in the budding yeast Saccharomyces cerevisiae assemble into self-replicating amyloid-like protein polymers, or prions, that act as genetic elements in an entirely protein-based system of inheritance. The nuclear pore complex (NPC) contains multiple Q/N-rich proteins whose self-assembly has also been proposed to underlie structural and functional properties of the NPC. Here we show that an essential sequence feature of these proteins—repeating GLFG motifs—strongly promotes their self-assembly into amyloids with characteristics of prions. Furthermore, we demonstrate that Nup100 can form bona fide prions, thus establishing a previously undiscovered ability of yeast GLFG nucleoporins to adopt this conformational state in vivo.

Halfmann, Randal; Wright, Jessica R.; Alberti, Simon; Lindquist, Susan; Rexach, Michael

2012-01-01

280

Game Dynamic Model for Yeast Development  

PubMed Central

Game theoretic models, along with replicator equations, have been applied successfully to the study of evolution of populations of competing species, including the growth of a population, the reaching of the population to an equilibrium state, and the evolutionary stability of the state. In this paper, we analyze a game model proposed by Gore et al. (2009) in their recent study on the co-development of two mixed yeast strains. We examine the mathematical properties of this model with varying experimental parameters. We simulate the growths of the yeast strains and compare them with the experimental results. We also compute and analyze the equilibrium state of the system and prove that it is asymptotically and evolutionarily stable.

Huang, Yuanyuan; Wu, Zhijun

2013-01-01

281

Mapping the functional yeast ABC transporter interactome.  

PubMed

ATP-binding cassette (ABC) transporters are a ubiquitous class of integral membrane proteins of immense clinical interest because of their strong association with human disease and pharmacology. To improve our understanding of these proteins, we used membrane yeast two-hybrid technology to map the protein interactome of all of the nonmitochondrial ABC transporters in the model organism Saccharomyces cerevisiae and combined this data with previously reported yeast ABC transporter interactions in the BioGRID database to generate a comprehensive, integrated 'interactome'. We show that ABC transporters physically associate with proteins involved in an unexpectedly diverse range of functions. We specifically examine the importance of the physical interactions of ABC transporters in both the regulation of one another and in the modulation of proteins involved in zinc homeostasis. The interaction network presented here will be a powerful resource for increasing our fundamental understanding of the cellular role and regulation of ABC transporters. PMID:23831759

Snider, Jamie; Hanif, Asad; Lee, Mid Eum; Jin, Ke; Yu, Analyn R; Graham, Chris; Chuk, Matthew; Damjanovic, Dunja; Wierzbicka, Marta; Tang, Priscilla; Balderes, Dina; Wong, Victoria; Jessulat, Matthew; Darowski, Katelyn D; San Luis, Bryan-Joseph; Shevelev, Igor; Sturley, Stephen L; Boone, Charles; Greenblatt, Jack F; Zhang, Zhaolei; Paumi, Christian M; Babu, Mohan; Park, Hay-Oak; Michaelis, Susan; Stagljar, Igor

2013-07-07

282

Yeast strains from Livingston Island, Antarctica.  

PubMed

Five yeast strains were isolated from soil and moss samples from the Livingston Island (Antarctica) and identified according to morphological cultural and physiological characteristics. All strains had an optimum growth temperature of 15 degrees C: none grew above 25 degrees C. They assimilated D-glucose, D-galactose, sucrose, cellobiose, trehalose, 2-keto-D-gluconate, D-xylose, D-ribose and melezitose. Four of them were nonfermentative, only one, which formed pseudomycelium fermented glucose, galactose, trehalose. Two strains were identified as pink-red yeasts belonging to genus Rhodotorula--R. minuta and R. mucilaginosa; two were related to the genus Cryptococcus--C. albidus and C. laurentii; one was Candida oleophila. PMID:11899471

Pavlova, K; Grigorova, D; Hristozova, T; Angelov, A

2001-01-01

283

Game dynamic model for yeast development.  

PubMed

Game theoretic models, along with replicator equations, have been applied successfully to the study of evolution of populations of competing species, including the growth of a population, the reaching of the population to an equilibrium state, and the evolutionary stability of the state. In this paper, we analyze a game model proposed by Gore et al. (Nature 456:253-256, 2009) in their recent study on the co-development of two mixed yeast strains. We examine the mathematical properties of this model with varying experimental parameters. We simulate the growths of the yeast strains and compare them with the experimental results. We also compute and analyze the equilibrium state of the system and prove that it is asymptotically and evolutionarily stable. PMID:22434448

Huang, Yuanyuan; Wu, Zhijun

2012-03-21

284

Nuclear organisation and RNAi in fission yeast.  

PubMed

Over the last decade, the fission yeast Schizosaccharomyces pombe has been used extensively for investigating RNA interference (RNAi)-mediated heterochromatin assembly. However, only recently have studies begun to shed light on the 3D organisation of chromatin and the RNAi machinery in the fission yeast nucleus. These studies indicate association of repressive and active chromatin with different regions of the nuclear periphery, similar to other model organisms, and clustering of functionally related genomic features. Unexpectedly, RNAi factors were shown to associate with nuclear pores and were implicated in the regulation of genomic features outside of the well-studied heterochromatic regions. Nuclear organisation is likely to contribute to substrate specificity of the RNAi pathway. However, further studies are required to elucidate the exact mechanisms and functional importance of this nuclear organisation. PMID:23453865

Woolcock, Katrina J; Bühler, Marc

2013-02-28

285

Dynamic Trans Interactions in Yeast Chromosomes  

PubMed Central

Three-dimensional organization of the genome is important for regulation of gene expression and maintenance of genomic stability. It also defines, and is defined by, contacts between different chromosomal loci. Interactions between loci positioned on different chromosomes, i.e. “trans” interactions are one type of such contacts. Here, we describe a case of inducible trans interaction in chromosomes of the budding yeast S. cerevisiae. Special DNA sequences, inserted in two ectopic chromosomal loci positioned in trans, pair with one another in an inducible manner. The spatial proximity diagnostic of pairing is observable by both chromosome capture analysis (3C) and epifluorescence microscopy in whole cells. Protein synthesis de novo appears to be required for this process. The three-dimensional organization of the yeast nucleus imposes a constraint on such pairing, presumably by dictating the probability with which the two sequences collide with one another.

Mirkin, Ekaterina V.; Chang, Frederick S.; Kleckner, Nancy

2013-01-01

286

A Sampling of the Yeast Proteome  

PubMed Central

In this study, we examined yeast proteins by two-dimensional (2D) gel electrophoresis and gathered quantitative information from about 1,400 spots. We found that there is an enormous range of protein abundance and, for identified spots, a good correlation between protein abundance, mRNA abundance, and codon bias. For each molecule of well-translated mRNA, there were about 4,000 molecules of protein. The relative abundance of proteins was measured in glucose and ethanol media. Protein turnover was examined and found to be insignificant for abundant proteins. Some phosphoproteins were identified. The behavior of proteins in differential centrifugation experiments was examined. Such experiments with 2D gels can give a global view of the yeast proteome.

Futcher, B.; Latter, G. I.; Monardo, P.; McLaughlin, C. S.; Garrels, J. I.

1999-01-01

287

Analysis of lipid particles from yeast.  

PubMed

Quantitative analysis of components from different subcellular fractions is a key to the understanding of metabolic function as well as to the origin, the biogenesis, and the crosstalk of organelles. The yeast is an excellent model organism to address such questions from the biochemical, molecular biological, and cell biological viewpoints. A yeast organelle which gained much interest during the last decade is the lipid particle/droplet (LP), a storage compartment for nonpolar lipids but at the same time an organelle actively contributing to cellular metabolism. In this chapter, we describe methods and techniques that are commonly used to analyze lipids from LP at the molecular level by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry. We provide an easy to follow guideline for the isolation of these organelles, the qualitative and quantitative analysis of lipid components and show results obtained with these methods. PMID:19763485

Connerth, Melanie; Grillitsch, Karlheinz; Köfeler, Harald; Daum, Günther

2009-01-01

288

Aneuploidy causes proteotoxic stress in yeast  

PubMed Central

Gains or losses of entire chromosomes lead to aneuploidy, a condition tolerated poorly in all eukaryotes analyzed to date. How aneuploidy affects organismal and cellular physiology is poorly understood. We found that aneuploid budding yeast cells are under proteotoxic stress. Aneuploid strains are prone to aggregation of endogenous proteins as well as of ectopically expressed hard-to-fold proteins such as those containing polyglutamine (polyQ) stretches. Protein aggregate formation in aneuploid yeast strains is likely due to limiting protein quality-control systems, since the proteasome and at least one chaperone family, Hsp90, are compromised in many aneuploid strains. The link between aneuploidy and the formation and persistence of protein aggregates could have important implications for diseases such as cancer and neurodegeneration.

Oromendia, Ana B.; Dodgson, Stacie E.; Amon, Angelika

2012-01-01

289

Intracellular trehalase of a hybrid yeast  

PubMed Central

1. The trehalase found in an extract prepared from a yeast strain that cannot ferment trehalose was studied and characterized. The enzyme is highly specific for trehalose with Km 1·02×10?2m, and an optimum pH of 6·9. 2. It is inhibited by glucose and by trehalose 6-phosphate, and does not facilitate any significant transglucosylations. 3. pK values 7·7 and 5·8 were detected for the groups associated with binding of the non-ionized substrate to the enzyme. 4. The trehalase was found to be highly labile and was inhibited by thiol-binding reagents. 5. The possible role of this enzyme in the trehalose-dissimilation patterns in the yeast cell was evaluated.

Avigad, G.; Ziv, Ofra; Neufeld, Edna

1965-01-01

290

[Yeast cell ultrastructure after amiodarone treatment].  

PubMed

[Amiodarone is used as a pharmaceutical substance for treating a number of diseases. However it is known that structural and functional disturbances are caused by amiodarone in patient's tissues. Here particular features of amiodarone effect are studied in yeast Saccharomyces cerevisiae, where amiodarone was shown to cause apoptosis. Electron-microscopic study of yeast cells after amiodarone treatment reveals a significant increase in lipid particle number which can lead to formation of a structural complex by interacting with membranous organelles of a cell. Amiodarone causes the appearance of small and separated slightly swollen mitochondria. Chro-matin displacement to the periphery of nucleus, nuclear sectioning and nuclear envelope disturbances are observed in the cells under these conditions. The detected cell ultrastructure alterations in the S. cerevisiae are considered to be specific response to the phospholipidosis and apoptosis caused by amiodarone. PMID:20058809

Ozhovan, S M; Knorre, D A; Severin, F F; Bakeeva, L E

2009-01-01

291

Human, yeast and hybrid 3-phosphoglycerate kinase gene expression in yeast.  

PubMed Central

When the gene for yeast 3-phosphoglycerate kinase (PGK) is present on a high copy number plasmid in Saccharomyces cerevisiae, 30-40 percent of yeast protein is produced as PGK. However, when the structural part of this gene is replaced by as many as twenty different heterologous genes, production of gene products is greatly reduced--usually by more than 20 fold. This decrease in protein production is accompanied by large decreases in the steady-state levels of mRNA. However, in contrast to these coding sequences, replacement of the yeast PGK structural gene with a human PGK cDNA has little effect on the steady-state mRNA level in yeast. PGK is a two-domain enzyme and its 3-dimensional structure is highly conserved among species. These observations and others have led us to propose that the PGK protein itself might influence its own mRNA levels (Chen et al., Nucleic Acids Res. 12, pp. 8951-8969, 1984). In addition, data is presented here which suggest that the human PGK mRNA is less efficiently translated than the yeast PGK mRNA. Two different mechanisms of controlling gene expression are indicated. Both mechanisms appear to be independent of gene copy number. Images

Chen, C Y; Hitzeman, R A

1987-01-01

292

Obese yeast: triglyceride lipolysis is functionally conserved from mammals to yeast.  

PubMed

Storage and degradation of triglycerides are essential processes to ensure energy homeostasis and availability of precursors for membrane lipid synthesis. Recent evidence suggests that an emerging class of enzymes containing a conserved patatin domain are centrally important players in lipid degradation. Here we describe the identification and characterization of a major triglyceride lipase of the adipose triglyceride lipase/Brummer family, Tgl4, in the yeast Saccharomyces cerevisiae. Elimination of Tgl4 in a tgl3 background led to fat yeast, rendering growing cells unable to degrade triglycerides. Tgl4 and Tgl3 lipases localized to lipid droplets, independent of each other. Serine 315 in the GXSXG lipase active site consensus sequence of the patatin domain of Tgl4 is essential for catalytic activity. Mouse adipose triglyceride lipase (which also contains a patatin domain but is otherwise highly divergent in primary structure from any yeast protein) localized to lipid droplets when expressed in yeast, and significantly restored triglyceride breakdown in tgl4 mutants in vivo. Our data identify yeast Tgl4 as a functional ortholog of mammalian adipose triglyceride lipase. PMID:16267052

Kurat, Christoph F; Natter, Klaus; Petschnigg, Julia; Wolinski, Heimo; Scheuringer, Kim; Scholz, Harald; Zimmermann, Robert; Leber, Regina; Zechner, Rudolf; Kohlwein, Sepp D

2005-11-02

293

A Sampling of the Yeast Proteome  

Microsoft Academic Search

In this study, we examined yeast proteins by two-dimensional (2D) gel electrophoresis and gathered quan- titative information from about 1,400 spots. We found that there is an enormous range of protein abundance and, for identified spots, a good correlation between protein abundance, mRNA abundance, and codon bias. For each molecule of well-translated mRNA, there were about 4,000 molecules of protein.

B. FUTCHER; G. I. LATTER; P. MONARDO; C. S. MCLAUGHLIN; J. I. GARRELS

1999-01-01

294

Alternative pathways of sterol synthesis in yeast  

Microsoft Academic Search

Yeast produce traces of aberrant sterols by minor alternative pathways, which can become significant when normal metabolism is blocked by inhibitors or mutations. We studied sterols generated in the absence of the ?8–?7 isomerase (Erg2p) or ?5 desaturase (Erg3p) by incubating three mutant strains of Saccharomyces cerevisiae with 5?-cholest-8-en-3?-ol, 8-dehydrocholesterol (?5,8 sterol), or isodehydrocholesterol (?6,8 sterol), together with the corresponding

Benfang Ruan; Peggy S Lai; Christine W Yeh; William K Wilson; Jihai Pang; Ran Xu; Seiichi P. T Matsuda; George J Schroepfer Jr.

2002-01-01

295

The mitochondrial pathway in yeast apoptosis  

Microsoft Academic Search

Mitochondria are not only important for the energetic status of the cell, but are also the fatal organelles deciding about\\u000a cellular life and death. Complex mitochondrial features decisive for cell death execution in mammals are present and functional\\u000a in yeast: AIF and cytochrome c release to the cytosol, mitochondrial fragmentation as well as mitochondrial hyperpolarisation followed by an oxidative burst,

Tobias Eisenberg; Sabrina Büttner; Guido Kroemer; Frank Madeo

2007-01-01

296

Amyloid formation of a yeast prion determinant  

Microsoft Academic Search

The [PSI\\u000a +] factor of the yeast Saccharomyces cerevisiae is a cytoplasmic, epigenetic regulator of translation termination and can be transmitted from mother to daughter cells in\\u000a a non-Mendelian manner. The transmission is caused by self-perpetuating noncovalent changes in the physical state of the protein\\u000a determinant Sup35p, rather than by changes in its encoding gene. This phenomenon is reminiscent of

Thomas Scheibel

2004-01-01

297

Uptake of Lanthanum by a Yeast  

Microsoft Academic Search

IN the course of studies of the barium metabolism of larval Drosophila which it is planned to report in full elsewhere, we have found that larvæ on a medium containing barium-140 showed lanthanum-140 enrichment if the medium had been inoculated with Texas Y-2 strain of yeast1 twenty-four hours before adding the larvæ, but barium-140 enrichment if the larvæ had been

V. T. Bowen; Ann C. Rubinson

1951-01-01

298

Complete DNA sequence of yeast chromosome XI  

Microsoft Academic Search

The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map

B. Dujon; D. Alexandraki; B. André; W. Ansorge; V. Baladron; J. P. G. Ballesta; A. Banrevi; P. A. Bolle; M. Bolotin-Fukuhara; P. Bossier; G. Bou; J. Boyer; M. J. Buitrago; G. Cherét; L. Colleaux; B. Dalgnan-Fornier; F. Del Rey; C. Dion; H. Domdey; A. Düsterhöft; S. Düsterhus; K.-D. Entian; H. Erfle; P. F. Esteban; H. Feldmann; L. Fernandes; G. M. Fobo; C. Fritz; H. Fukuhara; C. Gabel; L. Gaillon; J. M. Carcia-Cantalejo; J. J. Garcia-Ramirez; M. E. Gent; M. Ghazvini; A. Goffeau; A. Gonzaléz; D. Grothues; P. Guerreiro; J. Hegemann; N. Hewitt; F. Hilger; C. P. Hollenberg; O. Horaitis; K. J. Indge; A. Jacquier; C. M. James; J. C. Jauniaux; A. Jimenez; H. Keuchel; L. Kirchrath; K. Kleine; P. Kötter; P. Legrain; S. Liebl; E. J. Louis; A. Maia E Silva; C. Marck; A.-L. Monnier; D. Möstl; S. Müller; B. Obermaier; S. G. Oliver; C. Pallier; S. Pascolo; F. Pfeiffer; P. Philippsen; R. J. Planta; F. M. Pohl; T. M. Pohl; R. Pöhlmann; D. Portetelle; B. Purnelle; V. Puzos; M. Ramezani Rad; S. W. Rasmussen; M. Remacha; J. L. Revuelta; G.-F. Richard; M. Rieger; C. Rodrigues-Pousada; M. Rose; T. Rupp; M. A. Santos; C. Schwager; C. Sensen; J. Skala; H. Soares; F. Sor; J. Stegemann; H. Tettelin; A. Thierry; M. Tzermia; L. A. Urrestarazu; L. van Dyck; J. C. van Vliet-Reedijk; M. Valens; M. Vandenbo; C. Vilela; S. Vissers; D. von Wettstein; H. Voss; S. Wiemann; G. Xu; J. Zimmermann; M. Haasemann; I. Becker; H. W. Mewes

1994-01-01

299

A Method of isolating Protoplasts from Yeast  

Microsoft Academic Search

A NEW approach to the structure and functions of the cell surface of certain bacteria was revealed when Weibull1 showed that, in the presence of sucrose, lysozyme dissolves the cell-wall, leaving the protoplast essentially intact. Various attempts have since been made to isolate protoplasts from bacteria normally insensitive to lysozyme2 and also from yeast. Thus Necas3 showed that spontaneously autolysing

A. A. Eddy; D. H. Williamson

1957-01-01

300

MUTANTS OF YEAST DEFECTIVE IN SUCROSE UTILIZATION  

Microsoft Academic Search

Utilization of sucrose as a source of carbon and energy in yeast (Sac- charomyces) is controlled by the classical SUC genes, which confer the ability to produce the sucrose-degrading enzyme invertase ( MORTIMER and HAW- THORNE 1969). Mutants of S. cereuisiae strain S288C (SuCZ+) unable to grow anaerobically on sucrose, but still able to use glucose, were isolated. Two major

MARIAN CARLSON; BARBARA C. OSMOND; DAVID BOTSTEIN

1981-01-01

301

Regulation of phospholipid synthesis in yeast  

PubMed Central

Phospholipid synthesis in the yeast Saccharomyces cerevisiae is a complex process that involves regulation by both genetic and biochemical mechanisms. The activity levels of phospholipid synthesis enzymes are controlled by gene expression (e.g., transcription) and by factors (lipids, water-soluble phospholipid precursors and products, and covalent modification of phosphorylation) that modulate catalysis. Phosphatidic acid, whose levels are controlled by the biochemical regulation of key phospholipid synthesis enzymes, plays a central role in the regulation of phospholipid synthesis gene expression.

Carman, George M.; Han, Gil-Soo

2009-01-01

302

Silver tolerance and accumulation in yeasts  

Microsoft Academic Search

Summary Debaryomyces hansenii (NCYC 459 and strain 75-21),Candida albicans (3153A),Saccharomyces cerevisiae (X2180-1B),Rhodotorula rubra (NCYC 797) andAureobasidium pullulans (IMI 45533 and ATCC 42371) were grown on solid medium supplemented with varying concentrations of AgNO3. Although Ag+ is highly toxic towards yeasts, growth on solid media was still possible at Ag concentrations of 1–2 mM. Further subculture on higher Ag concentrations (up

Martin Kierans; A. Morven Staines; Heather Bennett; Geoffrey M. Gadd

1991-01-01

303

Anhydrobiosis in yeast: Stabilization by exogenous lactose  

Microsoft Academic Search

We have found that incubation in lactose solutions (0.75 M) of yeast culture Saccharomyces cerevisiae sensitive to dehydration damage increased the stability of the cells during dehydration. Simultaneously with this increase\\u000a in viability, a decrease in plasma membrane permeability during rehydration was seen. Using Fourier transform infrared spectroscopy\\u000a to measure lipid phase transitions, we observed that the lactose treatment depressed

A. I. Rapoport; G. M. Khroustalyova; L. M. Crowe; J. H. Crowe

2009-01-01

304

DNA damage checkpoint in budding yeast.  

PubMed Central

Eukaryotic cells have evolved a network of control mechanisms, known as checkpoints, which coordinate cell-cycle progression in response to internal and external cues. The yeast Saccharomyces cerevisiae has been invaluable in dissecting genetically the DNA damage checkpoint pathway. Recent results on posttranslational modifications and protein-protein interactions of some key factors provide new insights into the architecture of checkpoint protein complexes and their order of function.

Longhese, M P; Foiani, M; Muzi-Falconi, M; Lucchini, G; Plevani, P

1998-01-01

305

Phytase of the yeast Arxula adeninivorans  

Microsoft Academic Search

Of a number of yeasts screened for growth on phytic acid (inositol phosphates) as a sole source of carbon and phosphate, Arxula adeninivorans showed a particularly vigorous growth. This capacity was correlated with the presence of a high activity of secreted phytase. The crude enzyme showed an optimal temperature of at least 75?°C and an optimal pH of 4.5. The

Konosuke Sano; Hiroshi Fukuhara; Yoshihiro Nakamura

1999-01-01

306

The Assimilation of Glutamic Acid by Yeast  

Microsoft Academic Search

SUMMARY : Using the corresponding amino-acid decarboxylases, the six amino-acids arginine, glutamic acid, histidine, lysine, ornithine and tyrosine were found to be free inside the cells of yeast. They are present when growth takes place in the absence of amino-acids, but their concentration may be increased by growing the organisms in media rich in amino-acids. Uptake of glutamic acid from

E. SHIRLEY TAYLOR

1949-01-01

307

?-galactosidase from the yeast Candida javanica  

Microsoft Academic Search

Summary  ?-Galactosidase (Ec 3.2.1.22) was obtained from the yeast C. javanica grown on a mineral culture medium supplemented with melibiose plus raffinose. The cell-bound ?-galactosidase and the preparations\\u000a from the culture filtrate and from the cells exhibited maximum activity at pH 4 and 70C. After 15 min at 70C, 70% of the\\u000a ?-galactosidase activity was recovered, and after 15 min at

V. Cavazzoni; A. Adami; R. Craveri

1987-01-01

308

Transcriptional regulation of protein complexes in yeast  

Microsoft Academic Search

Background  Multiprotein complexes play an essential role in many cellular processes. But our knowledge of the mechanism of their formation,\\u000a regulation and lifetimes is very limited. We investigated transcriptional regulation of protein complexes in yeast using two\\u000a approaches. First, known regulons, manually curated or identified by genome-wide screens, were mapped onto the components\\u000a of multiprotein complexes. The complexes comprised manually curated

Nicolas Simonis; Jacques van Helden; George N Cohen; Shoshana J Wodak

2004-01-01

309

[Mitochondria inheritance in yeast saccharomyces cerevisiae].  

PubMed

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

Fizikova, A Iu

2011-01-01

310

Induction and construct UV protective yeast plasmid.  

PubMed

In this study, we apply concepts of synthetic biology in combination with conventional methods to assemble different genetic components to construct yeast resistant to UV radiation, and to induce production of anti-UV proteins. This work combines sequences of different promoters, STRESS-proteins, heat shock protein (HSP), kinase proteins, alcohol dehydrogenase protein (ADH), ribosomal binding sites, fluorescent reporter proteins, terminators, and a synthetic ribosomal switch. The aim of this investigation was to induce an anti-UV proteins, and to construct an anti-UV yeast plasmid to be used for protection of skin cells against UV radiation. This investigation demonstrates induction and construction of anti-UV genes and production of their corresponding proteins. Cultures of Saccharomyces cerevisiae (ATCC # 66348) were exposed to short-wave UV radiation and were then subjected to time-PCR to assess specific gene expression. Proteins were identified using two dimensional difference gel electrophoresis (2D DIGE) and LC-MS/MS. Different up-regulated and down-regulated proteins were identified. Highly expressed identified proteins were cloned into S. cerevisiae using a synthetic biology approach. Extracts from UV-induced genetically transformed yeasts were used to protect skin cell cultures (ATCC #2522-CRL) in vitro. Both microscopic analysis and an apoptosis assay showed protection of the skin cell cultures against UV radiation. PMID:23665192

Cuero, Raul; McKay, David S

2013-05-09

311

A microfluidic synchronizer for fission yeast cells.  

PubMed

Among all the cell cycle synchronization technologies, the baby machine may be considered as the most artifact-free method. A baby machine incubates "mother cells" under normal conditions and collects their "babies", producing cell cultures that are similar not only in cell cycle phase but also in age. Unlike many other synchronization methods, no cell-cycle-blocking agent or metabolic stress is introduced in this method. Several macroscale and microfluidic baby machines have been developed for producing synchronized cell colonies. However, for rod-shaped cells like fission yeast (Schizosaccharomyces pombe), it is still a challenge to immobilize only the mother cells in a microfluidic device. Here we presented a new baby machine suitable for fission yeast. The device is fixed one end of the cell and releases the free-end daughter cell every time the cell finishes cytokinesis. A variety of structures for cell immobilization were attempted to find the optimal design. For the convenience of collection and further assay, we integrated into our baby machine chip a cell screener, which exploited the deformation of polymer material to switch between opening and closing states. Synchronous populations of fission yeast cells were produced with this device, its working detail was analyzed and performance was evaluated. The device provides a new on-chip tool for cell biology studies. PMID:23966136

Tian, Yuan; Luo, Chunxiong; Ouyang, Qi

2013-08-21

312

Metabolic Engineering of Sesquiterpene Metabolism in Yeast  

PubMed Central

Terpenes are structurally diverse compounds that are of interest because of their biological activities and industrial value. These compounds consist of chirally rich hydrocarbon backbones derived from terpene synthases, which are subsequently decorated with hydroxyl substituents catalyzed by terpene hydroxylases. Availability of these compounds is, however, limited by intractable synthetic means and because they are produced in low amounts and as complex mixtures by natural sources. We engineered yeast for sesquiterpene accumulation by introducing genetic modifications that enable the yeast to accumulate high levels of the key intermediate farnesyl diphosphate (FPP). Co-expression of terpene synthase genes diverted the enlarged FPP pool to greater than 80 mg/L of sesquiterpene. Efficient coupling of terpene production with hydroxylation was also demonstrated by coordinate expression of terpene hydroxylase activity, yielding 50 mg/L each of hydrocarbon and hydroxylated products. These yeast now provide a convenient format for investigating catalytic coupling between terpene synthases and hydroxylases, as well as a platform for the industrial production of high value, single-entity and stereochemically unique terpenes.

Takahashi, Shunji; Yeo, Yunsoo; Greenhagen, Bryan T.; McMullin, Tom; Song, Linsheng; Maurina-Brunker, Julie; Rosson, Reinhardt; Noel, Joseph P.; Chappell, Joe

2010-01-01

313

Growth characteristics of bakers' yeast in ethanol  

SciTech Connect

The influence of temperature (15 - 40 degrees C) and pH (2.5 - 6.0) on the continuous growth of bakers' yeast (Saccharomyces cerevisiae) at steady state in 1% ethanol was investigated. Optimal temperature and pH were 30 degrees C and 4.5, respectively. The short-term effect of ethanol concentration (0.1 - 10.0%) on the yeast growth was assessed in batch culture. Up to 1% of ethanol, the yeast growth increased in function of the ethanol concentration in the medium. The biomass reached a maximum within the interval of 1-4% of ethanol (7.9 and 31.6 g/L, respectively) and decreased at higher concentrations. The residual ethanol concentration in the medium increased rapidly when the initial ethanol concentration exceeded 4%. The best-fit model obtained for growth inhibition as a function of ethanol concentrations was that of Tseng and Wayman: mu m S/(K+S) - i (S-S0). With this model, the specific growth rate (mu) decreased linearly as the ethanol concentration increased between the threshold value (S0) of 11.26 g/L to be fully inhibited at 70.00 g/L (S); an inhibition constant (i) of 0.0048 g/L/hour, a maximum specific growth rate (mu m) of 0.284/hour, and a saturation constant (K) of 0.611 g/L were obtained. (Refs. 17).

Wasungu, K.M.; Simard, R.E.

1980-05-01

314

Screening of yeast strains for phytase activity.  

PubMed

A screening method was developed to elucidate the ability of different yeast strains to utilize phytic acid as sole phosphorus source. The growth test in liquid culture in a microtiter plate with phytic acid as sole phosphorus source was shown to be a reliable, fast and easy-to-use screening method. We tested 122 strains from 61 species with our method and observed growth differences among species and strains that were not detectable on solid medium. Specific phytase activities were measured for 10 yeasts strains, selected due to their strong growth in the liquid medium. Strains of Arxula adeninivorans and Pichia anomala reached the highest volumetric phytase activities. Arxula adeninivorans also displayed the highest intra- and extracellular specific activities. There were large differences in both extra- and intracellular phytase activities among species. Strain-specific extracellular phytase activities were detected in P. anomala. The presence of free phosphate in the media completely suppressed the extracellular phytase activity and also reduced intracellular phytase activity for all tested yeast strains. PMID:19416106

Olstorpe, Matilda; Schnürer, Johan; Passoth, Volkmar

2009-05-01

315

Sugarcane bagasse hydrolysis using yeast cellulolytic enzymes.  

PubMed

Ethanol fuel production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable development. To use this biomass, it is necessary to circumvent the physical and chemical barriers presented by the cohesive combination of the main biomass components, which hinders the hydrolysis of cellulose and hemicellulose into fermentable sugars. This study evaluated the hydrolytic capacity of enzymes produced by yeasts, isolated from the soils of the Brazilian Cerrado biome (savannah) and the Amazon region, on sugarcane bagasse pre-treated with H2SO4. Among the 103 and 214 yeast isolates from the Minas Gerais Cerrado and the Amazon regions, 18 (17.47%) and 11 (5.14%) isolates, respectively, were cellulase-producing. Cryptococcus laurentii was prevalent and produced significant ?- glucosidase levels, which were higher than the endo- and exoglucanase activities. In natura sugarcane bagasse was pre-treated with 2% H2SO4 for 30 min at 150oC. Subsequently, the obtained fibrous residue was subjected to hydrolysis using the Cryptococcus laurentii yeast enzyme extract for 72 h. This enzyme extract promoted the conversion of approximately 32% of the cellulose, of which 2.4% was glucose, after the enzymatic hydrolysis reaction, suggesting that C. laurentii is a good ?-glucosidase producer. The results presented in this study highlight the importance of isolating microbial strains that produce enzymes of biotechnological interest, given their extensive application in biofuel production. PMID:23851270

Souza, Angelica Cristina de; Carvalho, Fernanda Paula; Silva E Batista, Cristina Ferreira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

2013-10-28

316

Hybrid yeast strains capable of raising an extraordinarily broad range of dough types  

Microsoft Academic Search

Over 200 hybrid yeast strains were screened and 11 of these found to have versatile fermentation characteristics. This paper reports the results obtained with these 11 strains compared with a commercially available strain of baker's yeast used for bread making and marketed as “instant active dry yeast”. In contrast to bakers yeast, the hybrid strains fermented very well in yeast,

S. Kowalski; I. Zander; S. Windisch

1981-01-01

317

Collaborative study on yeast activity, gas production (AACC Method 89-01)  

Microsoft Academic Search

A method of the American Association of Cereal Chemists (AACC) for determining yeast activity (gas production) was tested in a collaborative study involving five laboratories. Samples of three different manufacturers for each of three yeast types (three active dry yeasts, three compressed yeasts, and three instant active dry yeasts) were duplicated and tested in three dough formulations mainly characterized by

P Gélinas

1997-01-01

318

[Effect of cytochrome oxidase inhibitors on the yeast thermotolerance].  

PubMed

The investigation of the effect of the cytochrome oxidase inhibitors sodium cyanide and sodium azide on the thermotolerance of the yeasts Rhodotorula rubra, Debaryomyces vanriji, and Saccharomyces cerevisiae showed that these inhibitors diminish the thermotolerance of R. rubra and D. vanriji, but do not affect the thermotolerance of S. cerevisiae. Taking into account the fact that, unlike the latter yeast, R. rubra and D. vanriji are nonfermentative yeasts, the difference in the effects of the inhibitors on the yeast thermotolerance can be readily explained by the different types of glucose utilization (either oxidative or fermentative) in these yeasts. The data obtained also provide evidence that there is a correlation between the functional activity of mitochondria and the thermotolerance of yeast cells. PMID:12751239

Rikhvanov, E G; Varakina, N N; Rusaleva, T M; Rachenko, E I; Vo?nikov, V K

319

Isolation and characterization of ethanol tolerant yeast strains  

PubMed Central

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

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

2013-01-01

320

Frontiers of yeast metabolic engineering: diversifying beyond ethanol and Saccharomyces.  

PubMed

Microbial systems provide an attractive, renewable route to produce desired organic molecules such as fuels and chemicals. While attention within the field of metabolic engineering has mostly focused on Escherichia coli, yeast is a potent host and growing host for industrial products and has many outstanding, biotechnologically desirable native traits. Thus, there has been a recent shift in focus toward yeast as production hosts to replace E. coli. As such, products have diversified in yeast beyond simply ethanol. Additionally, nonconventional yeasts have been considered to move beyond Saccharomyces cerevisiae. This review highlights recent advances in metabolic engineering of yeasts for producing value-added chemical compounds including alcohols, sugar derivatives, organic acids, fats, terpenes, aromatics, and polyketides. Furthermore, we will also discuss the future direction of metabolic engineering of yeasts. PMID:23541504

Liu, Leqian; Redden, Heidi; Alper, Hal S

2013-03-28

321

Non-conventional yeasts as hosts for heterologous protein production.  

PubMed

Yeasts are an attractive group of lower eukaryotic microorganisms, some of which are used in several industrial processes that include brewing, baking and the production of a variety of biochemical compounds. More recently, yeasts have been developed as host organisms for the production of foreign (heterologous) proteins. Saccharomyces cerevisiae has usually been the yeast of choice, but an increasing number of alternative non-Saccharomyces yeasts has now become accessible for modern molecular genetics techniques. Some of them exhibit certain favourable traits such as high-level secretion or very strong and tightly regulated promoters, offering significant advantages over traditional bakers' yeast. In the present work, the current status of Kluyveromyces lactis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris (the best-known alternative yeast systems) is reviewed. The advantages and limitations of these systems are discussed in relation to S. cerevisiae. PMID:10943351

Domínguez, A; Fermiñán, E; Sánchez, M; González, F J; Pérez-Campo, F M; García, S; Herrero, A B; San Vicente, A; Cabello, J; Prado, M; Iglesias, F J; Choupina, A; Burguillo, F J; Fernández-Lago, L; López, M C

1998-06-01

322

Biosynthesis of the Torpedo californica Acetylcholine Receptor ? Subunit in Yeast  

NASA Astrophysics Data System (ADS)

Yeast cells were transformed with a plasmid containing complementary DNA encoding the ? subunit of the Torpedo californica acetylcholine receptor. These cells synthesized a protein that had the expected molecular weight, antigenic specificity, and ligand-binding properties of the ? subunit. The subunit was inserted into the yeast plasma membrane, demonstrating that yeast has the apparatus to express a membrane-bound receptor protein and to insert such a foreign protein into its plasma membrane. The ? subunit constituted approximately 1 percent of the total yeast membrane proteins, and its density was about the same in the plasma membrane of yeast and in the receptor-rich electric organ of Electrophorus electricus. In view of the available technology for obtaining large quantities of yeast proteins, it may now be possible to obtain amplified amounts of interesting membrane-bound proteins for physical and biochemical studies.

Fujita, Norihisa; Nelson, Nathan; Fox, Thomas D.; Claudio, Toni; Lindstrom, Jon; Riezman, Howard; Hess, George P.

1986-03-01

323

Gas bubble formation in the cytoplasm of a fermenting yeast  

PubMed Central

Abstract Current paradigms assume that gas bubbles cannot be formed within yeasts although these workhorses of the baking and brewing industries vigorously produce and release CO2 gas. We show that yeasts produce gas bubbles that fill a significant part of the cell. The missing link between intracellular CO2 production by glycolysis and eventual CO2 release from cells has therefore been resolved. Yeasts may serve as model to study CO2 behavior under pressurized conditions that may impact on fermentation biotechnology.

Swart, Chantel W; Dithebe, Khumisho; Pohl, Carolina H; Swart, Hendrik C; Coetsee, Elizabeth; van Wyk, Pieter WJ; Swarts, Jannie C; Lodolo, Elizabeth J; Kock, Johan LF

2012-01-01

324

Yeast growth: lag phase modelling in alcoholic media  

Microsoft Academic Search

A simple non-structured model is proposed here to evaluate the lag phase before yeast growth as a function of the ethanol concentration in the medium. Indeed, ethanol is the main yeast growth inhibitor acting in wine. So different cultures of Brettanomyces were run varying the initial ethanol content (0–90g\\/l). Its influence on yeast growth was shown. A term representing the

Wissam Medawar; Pierre Strehaiano; Marie-Line Délia

2003-01-01

325

Comparison of Yeast Growth in Mesquite Wood Hydrolysate  

PubMed Central

Hot-water extracts of mesquite (Prosopis glandulosa) wood were assayed for their total carbohydrate, reducing sugar, and glucose content. These hydrolysates were then used as complete media for yeast growth. A total of 10 strains of yeasts were evaluated for their biomass production in the mesquite wood hydrolysates. Levels of utilizable carbohydrate proved to be the limiting factor for yeast growth in the hydrolysates.

Stanlake, Gary J.

1986-01-01

326

Nitrate reductase from yeast: cultivation, partial purification and characterization  

Microsoft Academic Search

Several yeast strains were assayed for occurence of nitrate reductase after growth in a defined medium with nitrate as the sole nitrogen source, Candida boidinii DSM 70026, showing the highest specific activity, was further investigated. The procedures for yeast fermentation and nitrate reductase purfication are described in detail. Nitrate reductase from this yeast was characterized as NAD(P)H: nitrate oxidoreductase (E.C.1.6.6.2).

Reiner Gromes; Harry Schwartz; Martin Heinrich; Walther Johannssen

1991-01-01

327

Fluconazole and itraconazole susceptibility of vaginal yeast isolates from Slovakia  

Microsoft Academic Search

Vulvovaginal candidiasis is a common mucosal infection caused by opportunistic yeasts of the Candida genus. In this study, we isolated and identified the yeast species in the vagina of patients treated in the gynecology clinic\\u000a and tested in vitro activities of fluconazole and itraconazole against 227 clinical yeast isolates by the NCCLS microdilution\\u000a method. C. albicans (87.6%) was the most

Monika Sojakova; Denisa Liptajova; Miroslav Borovsky; Julius Subik

2004-01-01

328

The occurrence of killer character in yeasts of various genera  

Microsoft Academic Search

Species of 7 of the 28 yeast genera in the National Collection of Yeast Cultures exhibited killing activity againstSaccharomyces cerevisiae. The highest incidence of killer yeasts was found in the genusHansenula (12 of the 29 strains examined).Saccharomyces, the best represented genus in the Collection, showed a low incidence of killer activity and many of the killer strains are\\u000a hybrids with

G. Philliskirk; T. W. Young

1975-01-01

329

Prevalence of Candida dubliniensis Isolates in a Yeast Stock Collection  

Microsoft Academic Search

To establish the historical prevalence of the novel yeast species Candida dubliniensis, a survey of 2,589 yeasts originally identified as Candida albicans and maintained in a stock collection dating back to the early 1970s was undertaken. A total of 590 yeasts, including 93 (18.5%) b-glucosidase-negative isolates among 502 isolates that showed abnormal colony colors on a differential chromogenic agar and

FRANK C. ODDS; LUC VAN NUFFEL; GERY DAMS

1998-01-01

330

Cryoprotective effects of yeast extracellular polysaccharides and glycoproteins.  

PubMed

Eighteen yeast strains were tested for their ability to survive the freeze-thaw process while being cryoprotected. Cryoprotection was accomplished by combining penetrating and nonpenetrating cryoagents. Four nonpenetrating (two extracellular polysaccharides of yeast and two extracellular glycoproteins of yeast) and two penetrating agents were used together with the nutritive-rich medium. Eight different mixtures were tested. The highest survival rate was obtained with glycoproteins of Rhodosporidium toruloides together with DMSO and nutritive-rich medium. PMID:1499323

Breierová, E; Kocková-Kratochvílová, A

1992-06-01

331

Movement of Yeast Cortical Actin Cytoskeleton Visualized in vivo  

Microsoft Academic Search

Fusion proteins between the green fluorescent protein (GFP) and the cytoskeleton proteins Act1p (actin), Sac6p (yeast fimbrin homolog), and Abp1p in budding yeast (Saccharomyces cerevisiae) localize to the cortical actin patches. The actin fusions could not function as the sole actin source in yeast, but fusions between the actin-binding proteins Abp1p and Sac6p complement fully the phenotypes associated with their

Tim Doyle; David Botstein

1996-01-01

332

Influence of organic viticulture on non- Saccharomyces wine yeast populations  

Microsoft Academic Search

This study evaluated the population dynamics of non-Saccharomyces biota during spontaneous fermentation of organic musts. Non-Saccharomyces yeasts were found to be present at high levels during all fermentations. A total of 543 yeast colonies were isolated, 190\\u000a from Lysine-Medium (LM) agar, 254 from Wallerstein Laboratory Nutrient (WLN) agar and 99 from YPD agar. To estimate yeast\\u000a population dynamics during spontaneous

Rosanna Tofalo; Maria Schirone; Gianluca Ciro Telera; Anna Chiara Manetta; Aldo Corsetti; Giovanna Suzzi

2011-01-01

333

Relative Incidence of Ascomycetous Yeasts in Arctic Coastal Environments  

Microsoft Academic Search

Previous studies of fungi in polar environments have revealed a prevalence of basidiomycetous yeasts in soil and in subglacial\\u000a environments of polythermal glaciers. Ascomycetous yeasts have rarely been reported from extremely cold natural environments,\\u000a even though they are known contaminants of frozen foods. Using media with low water activity, we have isolated various yeast\\u000a species from the subglacial ice of

Lorena Butinar; Tadeja Strmole; Nina Gunde-Cimerman

2011-01-01

334

How to measure slow diffusion in yeast cell membranes  

NASA Astrophysics Data System (ADS)

Here we present two complementary methods for accurate diffusion measurements in yeast cell membranes. Fluorescence spreading after photobleaching analyzes the blurring of an initially sharp border between bleached and unbleached parts of the membrane. Two-focus scanning fluorescence correlation spectroscopy requires only a low concentration of labeled fluorophores and allows for very long measurement times due to correction for instabilities necessary to probe the slow diffusion in yeast plasma membranes. We apply these techniques to study the dynamics of different transmembrane proteins in the plasma membrane of the yeast Saccharomyces cerevisiae. The differences in the diffusion coefficients support the idea of co-existing membrane microdomains in the yeast plasma membrane.

Ries, Jonas; Klose, Christian; Walch-Solimena, Christiane; Schwille, Petra

2008-05-01

335

A Photometer for Measuring Population Growth in Yeast.  

ERIC Educational Resources Information Center

|Describes the construction and use of an inexpensive, portable photometer designed specifically for estimating population sizes in yeast cultures. Suggests activities for use with the photometer. (WRM)|

Tatina, Robert; Hartley, Tamela; Thomas, Danita

1999-01-01

336

A novel ascosporogenous yeast species, Zygosaccharomyces siamensis , and the sugar tolerant yeasts associated with raw honey collected in Thailand  

Microsoft Academic Search

Diversity of yeasts in association with bees and their food sources has been explored during the last decade. In Thailand,\\u000a there has been no study of yeast identification in honey and bees. Hence, a total of 186 yeast strains were isolated from\\u000a 37 honey samples of 12 different bee species. On the basis of morphological and physiological characteristics, 55 representative

Sujinan Saksinchai; Motofumi Suzuki; Panuwan Chantawannakul; Moriya Ohkuma; Saisamorn Lumyong

337

Histidine-Tagged Wild-Type Yeast Actin: Its Properties and Use in an Approach for Obtaining Yeast Actin Mutants  

Microsoft Academic Search

Wild-type and an N-terminal 6-histidine-tagged actin have each been expressed by using a yeast strain that contains the actin gene on a plasmid and not on the chromosome. Yeast strains have also been constructed that use two plasmids, one expressing the wild-type protein and the other the 6-histidine-tagged protein. Yeast cells can be grown with either plasmid alone or with

Jenny Buzan; Jinyan Du; Tatiana Karpova; Carl Frieden

1999-01-01

338

Characterisation of yeast microbial fuel cell with the yeast Arxula adeninivorans as the biocatalyst.  

PubMed

Yeast microbial fuel cells have received little attention to date. Yeast should be ideal MFC catalyst because they are robust, easily handled, mostly non-pathogenic organisms with high catabolic rates and in some cases a broad substrate spectrum. Here we show that the non-conventional yeast Arxula adeninvorans transfers electrons to an electrode through the secretion of a reduced molecule that is not detectable when washed cells are first resuspended but which accumulates rapidly in the extracellular environment. It is a single molecule that accumulates to a significant concentration. The occurrence of mediatorless electron transfer was first established in a conventional microbial fuel cell and that phenomenon was further investigated by a number of techniques. Cyclic voltammetry (CV) on a yeast pellet shows a single peak at 450mV, a scan rate study showed that the peak was due to a solution species. CVs of the supernatant confirmed a solution species. It appears that, given its other attributes, A. adeninivorans is a good candidate for further investigation as a MFC catalyst. PMID:21493057

Haslett, Nicholas D; Rawson, Frankie J; Barriëre, Frèdèric; Kunze, Gotthard; Pasco, Neil; Gooneratne, Ravi; Baronian, Keith H R

2011-02-16

339

Crystal structure of yeast Sco1  

SciTech Connect

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

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

2010-03-05

340

How does yeast respond to pressure?  

PubMed

The brewing and baking yeast Saccharomyces cerevisiae has been used as a model for stress response studies of eukaryotic cells. In this review we focus on the effect of high hydrostatic pressure (HHP) on S. cerevisiae. HHP exerts a broad effect on yeast cells characteristic of common stresses, mainly associated with protein alteration and lipid bilayer phase transition. Like most stresses, pressure induces cell cycle arrest. Below 50 MPa (500 atm) yeast cell morphology is unaffected whereas above 220 MPa wild-type cells are killed. S. cerevisiae cells can acquire barotolerance if they are pretreated with a sublethal stress due to temperature, ethanol, hydrogen peroxide, or pressure. Nevertheless, pressure only leads to protection against severe stress if, after pressure pretreatment, the cells are also re-incubated at room pressure. We attribute this effect to the inhibition of the protein synthesis apparatus under HHP. The global genome expression analysis of S. cerevisiae cells submitted to HHP revealed a stress response profile. The majority of the up-regulated genes are involved in stress defense and carbohydrate metabolism while most repressed genes belong to the cell cycle progression and protein synthesis categories. However, the signaling pathway involved in the pressure response is still to be elucidated. Nitric oxide, a signaling molecule involved in the regulation of a large number of cellular functions, confers baroprotection. Furthermore, S. cerevisiae cells in the early exponential phase submitted to 50-MPa pressure show induction of the expression level of the nitric oxide synthase inducible isoform. As pressure becomes an important biotechnological tool, studies concerning this kind of stress in microorganisms are imperative. PMID:16082465

Fernandes, P M B

2005-07-30

341

Specificity of Transmembrane Protein Palmitoylation in Yeast  

PubMed Central

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

Gonzalez Montoro, Ayelen; Chumpen Ramirez, Sabrina; Quiroga, Rodrigo; Valdez Taubas, Javier

2011-01-01

342

Molecular evolution of minisatellites in hemiascomycetous yeasts.  

PubMed

Minisatellites are DNA tandem repeats exhibiting size polymorphism among individuals of a population. This polymorphism is generated by two different mechanisms, both in human and yeast cells, "replication slippage" during S-phase DNA synthesis and "repair slippage" associated to meiotic gene conversion. The Saccharomyces cerevisiae genome contains numerous natural minisatellites. They are located on all chromosomes without any obvious distribution bias. Minisatellites found in protein-coding genes have longer repeat units and on the average more repeat units than minisatellites in noncoding regions. They show an excess of cytosines on the coding strand, as compared to guanines (negative GC skew). They are always multiples of three, encode serine- and threonine-rich amino acid repeats, and are found preferably within genes encoding cell wall proteins, suggesting that they are positively selected in this particular class of genes. Genome-wide, there is no statistically significant association between minisatellites and meiotic recombination hot spots. In addition, minisatellites that are located in the vicinity of a meiotic hot spot are not more polymorphic than minisatellites located far from any hot spot. This suggests that minisatellites, in S. cerevisiae, evolve probably by strand slippage during replication or mitotic recombination. Finally, evolution of minisatellites among hemiascomycetous yeasts shows that even though many minisatellite-containing genes are conserved, most of the time the minisatellite itself is not conserved. The diversity of minisatellite sequences found in orthologous genes of different species suggests that minisatellites are differentially acquired and lost during evolution of hemiascomycetous yeasts at a pace faster than the genes containing them. PMID:16177231

Richard, Guy-Franck; Dujon, Bernard

2005-09-21

343

Dynamic modeling of yeast meiotic initiation  

PubMed Central

Background Meiosis is the sexual reproduction process common to eukaryotes. The diploid yeast Saccharomyces cerevisiae undergoes meiosis in sporulation medium to form four haploid spores. Initiation of the process is tightly controlled by intricate networks of positive and negative feedback loops. Intriguingly, expression of early meiotic proteins occurs within a narrow time window. Further, sporulation efficiency is strikingly different for yeast strains with distinct mutations or genetic backgrounds. To investigate signal transduction pathways that regulate transient protein expression and sporulation efficiency, we develop a mathematical model using ordinary differential equations. The model describes early meiotic events, particularly feedback mechanisms at the system level and phosphorylation of signaling molecules for regulating protein activities. Results The mathematical model is capable of simulating the orderly and transient dynamics of meiotic proteins including Ime1, the master regulator of meiotic initiation, and Ime2, a kinase encoded by an early gene. The model is validated by quantitative sporulation phenotypes of single-gene knockouts. Thus, we can use the model to make novel predictions on the cooperation between proteins in the signaling pathway. Virtual perturbations on feedback loops suggest that both positive and negative feedback loops are required to terminate expression of early meiotic proteins. Bifurcation analyses on feedback loops indicate that multiple feedback loops are coordinated to modulate sporulation efficiency. In particular, positive auto-regulation of Ime2 produces a bistable system with a normal meiotic state and a more efficient meiotic state. Conclusions By systematically scanning through feedback loops in the mathematical model, we demonstrate that, in yeast, the decisions to terminate protein expression and to sporulate at different efficiencies stem from feedback signals toward the master regulator Ime1 and the early meiotic protein Ime2. We argue that the architecture of meiotic initiation pathway generates a robust mechanism that assures a rapid and complete transition into meiosis. This type of systems-level regulation is a commonly used mechanism controlling developmental programs in yeast and other organisms. Our mathematical model uncovers key regulations that can be manipulated to enhance sporulation efficiency, an important first step in the development of new strategies for producing gametes with high quality and quantity.

2013-01-01

344

Cell Polarization and Cytokinesis in Budding Yeast  

PubMed Central

Asymmetric cell division, which includes cell polarization and cytokinesis, is essential for generating cell diversity during development. The budding yeast Saccharomyces cerevisiae reproduces by asymmetric cell division, and has thus served as an attractive model for unraveling the general principles of eukaryotic cell polarization and cytokinesis. Polarity development requires G-protein signaling, cytoskeletal polarization, and exocytosis, whereas cytokinesis requires concerted actions of a contractile actomyosin ring and targeted membrane deposition. In this chapter, we discuss the mechanics and spatial control of polarity development and cytokinesis, emphasizing the key concepts, mechanisms, and emerging questions in the field.

Bi, Erfei; Park, Hay-Oak

2012-01-01

345

Sequential utilization of mixed monosaccharides by yeasts.  

PubMed Central

Four yeasts (Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida utilus, and Rhodotorula toruloides) were tested for their ability to grow and consume D-glucose, D-xylose, D-xylulose, and D-xylitol. Sequential utilization of substrates was observed when D-glucose as mixed with D-xylulose as the carbon source. Catabolite inhibition was tentatively concluded to be responsible for this regulatory mechanism. D-Glucose was also found to inhibit the utilization of D-xylose and D-xylitol in C. utilus and R. toruloides. D-Xylose, D-xylitol, and D-xylulose were consumed simultaneously by R. toruloides and C. utilus.

Hsiao, H Y; Chiang, L C; Ueng, P P; Tsao, G T

1982-01-01

346

Fanconi-like crosslink repair in yeast  

PubMed Central

Interstrand crosslinks covalently link complementary DNA strands, block replication and transcription, and can trigger cell death. In eukaryotic systems several pathways, including the Fanconi Anemia pathway, are involved in repairing interstrand crosslinks, but their precise mechanisms remain enigmatic. The lack of functional homologs in simpler model organisms has significantly hampered progress in this field. Two recent studies have finally identified a Fanconi-like interstrand crosslink repair pathway in yeast. Future studies in this simplistic model organism promise to greatly improve our basic understanding of complex interstrand crosslink repair pathways like the Fanconi pathway.

2012-01-01

347

Yeast mutants auxotrophic for choline or ethanolamine.  

PubMed Central

Three mutants of the yeast Saccharomyces cerevisiae which require exogenous ethanolamine or choline were isolated. The mutants map to a single locus (cho1) on chromosome V. The lipid composition suggests that cho1 mutants do not synthesize phosphatidylserine under any growth conditions. If phosphatidylethanolamine or phosphatidylcholine, which are usually derived from phosphatidylserine, were synthesized from exogenous ethanolamine or choline, the mutants grew and divided relatively normally. However, mitochondrial abnormalities were evident even when ethanolamine and choline were supplied. Diploids homozygous for the cho1 mutation were defective in sporulation. Growth on nonfermentable carbon sources was slow, and a high proportion of respiratory-deficient (petite) cells were generated in cho1 cultures.

Atkinson, K D; Jensen, B; Kolat, A I; Storm, E M; Henry, S A; Fogel, S

1980-01-01

348

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

PubMed

Vanillin is one of the world's most important flavor compounds, with a global market of 180 million dollars. Natural vanillin is derived from the cured seed pods of the vanilla orchid (Vanilla planifolia), but most of the world's vanillin is synthesized from petrochemicals or wood pulp lignins. We have established a true de novo biosynthetic pathway for vanillin production from glucose in Schizosaccharomyces pombe, also known as fission yeast or African beer yeast, as well as in baker's yeast, Saccharomyces cerevisiae. Productivities were 65 and 45 mg/liter, after introduction of three and four heterologous genes, respectively. The engineered pathways involve incorporation of 3-dehydroshikimate dehydratase from the dung mold Podospora pauciseta, an aromatic carboxylic acid reductase (ACAR) from a bacterium of the Nocardia genus, and an O-methyltransferase from Homo sapiens. In S. cerevisiae, the ACAR enzyme required activation by phosphopantetheinylation, and this was achieved by coexpression of a Corynebacterium glutamicum phosphopantetheinyl transferase. Prevention of reduction of vanillin to vanillyl alcohol was achieved by knockout of the host alcohol dehydrogenase ADH6. In S. pombe, the biosynthesis was further improved by introduction of an Arabidopsis thaliana family 1 UDP-glycosyltransferase, converting vanillin into vanillin beta-D-glucoside, which is not toxic to the yeast cells and thus may be accumulated in larger amounts. These de novo pathways represent the first examples of one-cell microbial generation of these valuable compounds from glucose. S. pombe yeast has not previously been metabolically engineered to produce any valuable, industrially scalable, white biotech commodity. PMID:19286778

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

2009-03-13

349

Immobilized yeast cell systems for continuous fermentation applications  

Microsoft Academic Search

In several yeast-related industries, continuous fermentation systems offer important economical advantages in comparison with traditional systems. Fermentation rates are significantly improved, especially when continuous fermentation is combined with cell immobilization techniques to increase the yeast concentration in the fermentor. Hence the technique holds a great promise for the efficient production of fermented beverages, such as beer, wine and cider as

Pieter J. Verbelen; David P. De Schutter; Filip Delvaux; Kevin J. Verstrepen; Freddy R. Delvaux

2006-01-01

350

Oxygen Stress: A Regulator of Apoptosis in Yeast  

Microsoft Academic Search

Oxygen radicals are important components of metazoan apoptosis. We have found that apoptosis can be induced in the yeast Saccharomyces cerevisiae by depletion of glutathione or by low external doses of H 2 O 2 . Cycloheximide prevents apoptotic death reveal- ing active participation of the cell. Yeast can also be triggered into apoptosis by a mutation in CDC48 or

Frank Madeo; Eleonore Fröhlich; Martin Ligr; Martin Grey; Stephan J. Sigrist; Dieter H. Wolf; Kai-Uwe Fröhlich

1999-01-01

351

Diversity of commensal yeasts within and among healthy hosts  

Microsoft Academic Search

We sampled commensal yeasts from three body sites of 24 healthy individuals to examine the patterns of commensal yeast species distribution and strain relatedness within and among individuals. To examine the short-term dynamics, each individual was sampled three times every 35–40 days at each of three body sites: mouth, fingernail, and toenail. The hosts included six genealogically unrelated individuals and

Angela P. Kam; Jianping Xu

2002-01-01

352

Fuel Ethanol Production from Molasses by Some Indigenous Yeast Isolates  

Microsoft Academic Search

In view of the anticipated shortage of the traditional supplies of fossil fuels there is a great deal of interest in production of ethanol as an alternative biofuel in recent years. The present report describes the search for potential yeast isolates from various ferments capable of producing ethanol. Twenty-one indigenous yeast isolates were recovered from various sources. Thirteen of them

Sabera Hasibe Sheela; M Firoz Ahmed; Donald James Gomes

2008-01-01

353

Biogeography of the yeasts of ephemeral flowers and their insects  

Microsoft Academic Search

We studied specific yeast communities vectored by beetles, drosophilids, and bees that visit ephemeral flowers, mostly in the genus Hibiscus and in the families Convolvulaceae and Cactaceae, in the Neotropical, Nearctic, and Australian biogeographic regions. The communities consist mostly of yeasts in four clades centered around the genera Metschnikowia, Kodamaea, Wickerhamiella, and Starmerella. The largest geographic discontinuity occurs as a

Marc-André Lachance; William T. Starmer; Carlos A. Rosa; Jane M. Bowles; J. Stuart F. Barker; Daniel H. Janzen

2001-01-01

354

Yeasts as adjunct starters in matured Cheddar cheese  

Microsoft Academic Search

Debaryomyces hansenii and Yarrowia lipolytica are typical foodborne yeast species frequently associated with dairy products and capable of predominating the yeast composition in such systems. The two species fulfil a number of criteria to be regarded as co-starters for cheesemaking. They are known for their proteolytic and lipolytic activity as well as their compatibility and stimulating action with the lactic

A. D. Ferreira; B. C. Viljoen

2003-01-01

355

Biomass production of yeast isolate from salad oil manufacturing wastewater  

Microsoft Academic Search

Conversion of oil-rich salad oil manufacturing wastewater (SOMW) into protein source for animal feed through biomass production of yeast isolate was investigated in this study. Five species of yeasts, including Rhodotorula rubra, Candida tropicalis, C. utilis, C. boidinii, Trichosporon cutaneum, were isolated from SOMW following enrichment culture. Of them, C. utilis was chosen as the sole biomass producer in the

Shaokui Zheng; Min Yang; Zhifeng Yang

2005-01-01

356

Early Expression of Yeast Genes Affected by Chemical Stress  

Microsoft Academic Search

The variety of environmental stresses is probably the major challenge imposed on transcription activators and the transcriptional machinery. To precisely describe the very early genomic response developed by yeast to accommodate a chemical stress, we performed time course analyses of the modifications of the yeast gene expression program which immediately follows the addition of the antimitotic drug benomyl. Similar analyses

A. Lucau-Danila; G. Lelandais; Z. Kozovska; V. Tanty; T. Delaveau; F. Devaux; C. Jacq

2005-01-01

357

Global analysis of protein localization in budding yeast  

Microsoft Academic Search

A fundamental goal of cell biology is to define the functions of proteins in the context of compartments that organize them in the cellular environment. Here we describe the construction and analysis of a collection of yeast strains expressing full-length, chromosomally tagged green fluorescent protein fusion proteins. We classify these proteins, representing 75% of the yeast proteome, into 22 distinct

Won-Ki Huh; James V. Falvo; Luke C. Gerke; Adam S. Carroll; Russell W. Howson; Jonathan S. Weissman; Erin K. O'Shea

2003-01-01

358

Water permeability of yeast cells at sub-zero temperatures  

Microsoft Academic Search

Summary A combined cryomicroscopic-multiple nonlinear regression analysis technique has been used to determine the water permeability of the yeast cellSaccharomyces cerevisiae during freezing. The time rate of change in volume of “supercooled” yeast cells was photographically monitored using a “cryomicroscope” which is capable of controlling in a programmable manner both the temperature and the time rate of change in temperature

Ronald L. Levin; M. Ushiyama; E. G. Cravalho

1979-01-01

359

Genomic adaptation of ethanologenic yeast to biomass conversion inhibitors  

Microsoft Academic Search

One major barrier to the economic conversion of biomass to ethanol is inhibitory compounds generated during biomass pretreatment using dilute acid hydrolysis. Major inhibitors such as furfural and 5-hydroxymethylfurfural (HMF) inhibit yeast growth and subsequent fermentation. The ethanologenic yeast Saccharomyces cerevisiae demonstrated a dose-dependant inhibition by the inhibitors and has the potential to transform furfural and HMF into less toxic

Z. Lewis Liu

2006-01-01

360

Iron enriched yeast biomass – A promising mineral feed supplement  

Microsoft Academic Search

Yeast biomass enriched with iron could represent a new and safer solution for prevention from anaemia development. Such an iron source is less toxic and has better absorbability in organisms. The purpose of our research was the determination of the most suitable iron source in the cultivation medium for the yeast Saccharomyces cerevisiae, regarding good growth and iron accumulation in

Maja Paš; Barbara Piškur; Matevž Šuštari?; Peter Raspor

2007-01-01

361

Ascospore aggregation and oxylipin distribution in the yeast Dipodascopsis tothii  

Microsoft Academic Search

Upon cultivation of the yeast Dipodascopsis tothii in its sexual stage, small ascospores are released individually from the ascus tip, which then assemble in sheathed cluster balls. In contrast to Dipodascopsis uninucleata, this yeast produced smooth bean shaped ascospores with sheath-like appendages that assemble in a disordered sheathed ball of ascospores outside the ascus. Strikingly, upon release, the ascus tip

D. P. Smith; J. L. F. Kock; M. I. Motaung; P. W. J. van Wyk; P. Venter; D. J. Coetzee; S. Nigam

2000-01-01

362

Cultivable psychrotolerant yeasts associated with Antarctic marine sponges.  

PubMed

Unlike filamentous fungi and bacteria, very little is known about cultivable yeasts associated with marine sponges, especially those from Antarctic seas. During an expedition to King George Island, in the Antarctica, samples of 11 marine sponges were collected by scuba-diving. From these sponges, 20 psychrotolerant yeast isolates were obtained. Phylogenetic analyses of D1/D2 and ITS rRNA gene sequences revealed that the marine ascomycetous yeast Metschnikowia australis is the predominant organism associated with these invertebrates. Other species found belonged to the Basidiomycota phylum: Cystofilobasidium infirmominiatum, Rhodotorula pinicola, Leucosporidiella creatinivora and a new yeast from the Leucosporidiella genus. None of these yeasts have been previously associated with marine sponges. A screening to estimate the ability of these yeasts as producers of extracellular enzymatic activities at several pH and temperature conditions was performed. Several yeast isolates demonstrated amylolytic, proteolytic, lipolytic or cellulolytic activity, but none of them showed xylanolytic activity under the conditions assayed. To our knowledge, this work is the first description of cultivable yeasts associated with marine sponges from the Antarctic sea. PMID:22927015

Vaca, Inmaculada; Faúndez, Carolina; Maza, Felipe; Paillavil, Braulio; Hernández, Valentina; Acosta, Fermín; Levicán, Gloria; Martínez, Claudio; Chávez, Renato

2012-08-28

363

Analysis of the inhibition of food spoilage yeasts by vanillin  

Microsoft Academic Search

The antimicrobial potential of vanillin, the major component of vanilla flavour, was examined against the growth of three yeasts associated with food spoilage, Saccharomyces cerevisiae, Zygosaccharomyces bailii and Zygosaccharomyces rouxii. Minimum inhibitory concentration (MIC) values of 21, 20 and 13 mM vanillin were determined for the three yeast strains, respectively. The observed inhibition was found to be biostatic. During fermentation,

Daniel J Fitzgerald; Malcolm Stratford; Arjan Narbad

2003-01-01

364

Extremely Rapid Extraction of DNA from Bacteria and Yeasts  

Microsoft Academic Search

A very simple and rapid method for extracting genomic DNA from Gram-negative bacteria, Gram-positive bacteria and yeasts is presented. In this method, bacteria or yeasts are lysed directly by phenol and the supernatant is extracted with chloroform to remove traces of phenol. The supernatant contains DNA that is suitable for molecular analyses, such as PCR, restriction enzyme digestion and genomic

Hai-Rong Cheng; Ning Jiang

2006-01-01

365

Construction and properties of K1 type killer wine yeasts  

Microsoft Academic Search

Summary With the use of a protoplast fusion technique the killer character of K1 type was transferred into four industrial Saccharomyces wine yeasts. The prototrophic yeast strains active against standard sensitive and K2 killer Saccharomyces strains, resistant to K1 killer toxin were constructed with no changes in technological properties.

P. Sulo; S. Michal?áková; V. Reiser

1992-01-01

366

Dielectric modelling of cell division for budding and fission yeast  

NASA Astrophysics Data System (ADS)

The frequency dependence of complex permittivity or the dielectric spectrum of a system including a cell in cell division has been simulated by a numerical technique based on the three-dimensional finite difference method. Two different types of cell division characteristic of budding and fission yeast were examined. The yeast cells are both regarded as a body of rotation, and thus have anisotropic polarization, i.e. the effective permittivity of the cell depends on the orientation of the cell to the direction of an applied electric field. In the perpendicular orientation, where the rotational axis of the cell is perpendicular to the electric field direction, the dielectric spectra for both yeast cells included one dielectric relaxation and its intensity depended on the cell volume. In the parallel orientation, on the other hand, two dielectric relaxations appeared with bud growth for budding yeast and with septum formation for fission yeast. The low-frequency relaxation was shifted to a lower frequency region by narrowing the neck between the bud and the mother cell for budding yeast and by increasing the degree of septum formation for fission yeast. After cell separation, the low-frequency relaxation disappeared. The simulations well interpreted the oscillation of the relative permittivity of culture broth found for synchronous cell growth of budding yeast.

Asami, Koji; Sekine, Katsuhisa

2007-02-01

367

A Survey of the Antibiotic Powers of Yeasts  

Microsoft Academic Search

Only one systematic study has been reported in which the inhibitory powers, against bacteria and other organisms, of a large number of different strains of yeasts have been observed. In a brief report, Koch (1952) described the screening, by means of a diffusion plate method, of about 150 yeasts including distilling, baking, brewing and other strains against the bacteria, Bacillus

I. C. MACWILLIAM

1959-01-01

368

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

ERIC Educational Resources Information Center

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

Deutch, Charles E.; Marshall, Pamela A.

2008-01-01

369

Mechanism of Caffeine-Induced Checkpoint Override in Fission Yeast  

Microsoft Academic Search

Mitotic checkpoints restrain the onset of mitosis (M) when DNA is incompletely replicated or damaged. These checkpoints are conserved between the fission yeast Schizosaccharomyces pombe and mammals. In both types of organisms, the methylxanthine caffeine overrides the synthesis (S)-M checkpoint that couples mitosis to completion of DNA S phase. The molecular target of caffeine was sought in fission yeast. Caffeine

BETTINA A. MOSER; JEAN-MARC BRONDELLO; BETH BABER-FURNARI; PAUL RUSSELL

2000-01-01

370

Exploring the Ubiquitin-Proteasome Protein Degradation Pathway in Yeast  

ERIC Educational Resources Information Center

|This article describes an undergraduate biochemistry laboratory investigating the ubiquitin-proteasome pathway in yeast. In this exercise, the enzyme beta-galactosidase (beta-gal) is expressed in yeast under the control of a stress response promoter. Following exposure to heat stress to induce beta-gal expression, cycloheximide is added to halt…

Will, Tamara J.; McWatters, Melissa K.; McQuade, Kristi L.

2006-01-01

371

Kinetics of growth and sugar consumption in yeasts  

Microsoft Academic Search

An overview is presented of the steady- and transient state kinetics of growth and formation of metabolic byproducts in yeasts.Saccharomyces cerevisiae is strongly inclined to perform alcoholic fermentation. Even under fully aerobic conditions, ethanol is produced by this yeast when sugars are present in excess. This so-called ‘Crabtree effect’ probably results from a multiplicity of factors, including the mode of

Johannes R van Dijken; Ruud A. Weusthuis; Jack T. Pronk

1993-01-01

372

Biotechnology of non-Saccharomyces yeasts--the ascomycetes.  

PubMed

Saccharomyces cerevisiae and several other yeast species are among the most important groups of biotechnological organisms. S. cerevisiae and closely related ascomycetous yeasts are the major producer of biotechnology products worldwide, exceeding other groups of industrial microorganisms in productivity and economic revenues. Traditional industrial attributes of the S. cerevisiae group include their primary roles in food fermentations such as beers, cider, wines, sake, distilled spirits, bakery products, cheese, sausages, and other fermented foods. Other long-standing industrial processes involving S. cerevisae yeasts are production of fuel ethanol, single-cell protein (SCP), feeds and fodder, industrial enzymes, and small molecular weight metabolites. More recently, non-Saccharomyces yeasts (non-conventional yeasts) have been utilized as industrial organisms for a variety of biotechnological roles. Non-Saccharomyces yeasts are increasingly being used as hosts for expression of proteins, biocatalysts and multi-enzyme pathways for the synthesis of fine chemicals and small molecular weight compounds of medicinal and nutritional importance. Non-Saccharomyces yeasts also have important roles in agriculture as agents of biocontrol, bioremediation, and as indicators of environmental quality. Several of these products and processes have reached commercial utility, while others are in advanced development. The objective of this mini-review is to describe processes currently used by industry and those in developmental stages and close to commercialization primarily from non-Saccharomyces yeasts with an emphasis on new opportunities. The utility of S. cerevisiae in heterologous production of selected products is also described. PMID:23184219

Johnson, Eric A

2012-11-27

373

Formulation and Cost-Effective Drying of Probiotic Yeast  

Microsoft Academic Search

Saccharomyces boulardii yeast is considered as a probiotic according to the World Health Organization (WHO). Like any other probiotic, Saccharomyces boulardii is available as a freeze-dried formulation. Although freeze drying is the most preferred method of preserving the microorganisms, the process is very expensive. The cost of capsules containing freeze-dried probiotic yeast is certainly out of reach of the underprivileged

Varsha S. Joshi; Bhaskar N. Thorat

2011-01-01

374

Spray Drying of Extracts from Red Yeast Fermentation Broth  

Microsoft Academic Search

Red yeast rice is a pigmented material that is traditionally used in Asia as a food colorant. In addition to food applications, red yeast rice is known in traditional Chinese medicine for its therapeutic actions. The aim of this work was to study the quality interactions during spray drying of extracts from the Monascus ruber van Tiegham fermentation broth. The

C. C. C. Teixeira; G. A. Teixeira; L. A. P. Freitas

2011-01-01

375

Mechanical dispersion procedures improve the rehydration of active dry yeast  

Microsoft Academic Search

The process of reactivating the yeast preparation and inoculating it into the must constitutes a critical stage in the management of alcoholic fermentation.Various parameters condition the efficiency of active dry yeast (ADY) reactivation for oenological use: temperature, composition of the medium (concentration of sugar and assimilable nitrogen), the way of dispersion in water and associated hydration times.This paper reports the

Roberto Ferrarini; Enrico Bocca; Agostino Cavazza

2007-01-01

376

Baker's yeast assay procedure for testing heavy metal toxicity  

Microsoft Academic Search

Baker's yeast (Saccharomyces cerevisiae) is microorganism which is commercially available and sold as packaged dry pellets in any food store at low cost. Studies have been undertaken on the effects of organic xenobiotics as well as heavy metals on yeast metabolism. This type of study has been generally useful in examining the mechanism(s) of chemical toxicity. However, a rapid and

Gabriel Bitton; Ben Koopman; Hsien-Deng Wang

1984-01-01

377

Vitality enhancement of the rehydrated active dry wine yeast  

Microsoft Academic Search

In winemaking, spontaneous grape must fermentations have been replaced by inoculation of commercial active dry wine yeast (ADWY). Yeast rehydration is the key to avoiding stuck and sluggish fermentations. Despite the importance of this step, not enough is known about what this process implies for winemaking as a whole or about what kind of practices could help to improve it.

B. Rodríguez-Porrata; M. Novo; J. Guillamón; N. Rozès; A. Mas; R. Cordero Otero

2008-01-01

378

Metabolic acclimatization: preparing active dry yeast for fuel ethanol production  

Microsoft Academic Search

“Propagation” or “conditioning” of active dry yeast (ADY) for the production of fuel ethanol is thought to reduce lag times in fermentation and reduce overall fermentation times. The objectives of this study were to determine the optimal time that ADY should be conditioned prior to fermentation and to determine how well yeast and bacterial contaminants present in ADY are propagated.

E. Bellissimi; W. M. Ingledew

2005-01-01

379

10 Non-conventional yeasts in antifungal application  

Microsoft Academic Search

The antimicrobial, and hence antifungal effects of yeast-produced ethanol has been recognised for centuries. Application of yeasts for biocontrol of fungi in agriculture, postharvest technology, forest industry, and food science presents a new area of biotechnology. Biocontrol environments are complex; consequently, there is an enormous diversity among the organisms involved in biocontrol and of inhibition mechanisms. Current genetic approaches focus

Volkmar Passoth; Johan Schnürer

380

Novel Yeast Genomics Method for Identifying New Breast Cancer Susceptibility.  

National Technical Information Service (NTIS)

We are attempting to identify novel genes in the yeast AND cerevisiae that confer gross chromosomal instability (GCI) a hallmark of most breast cancers when deleted. Using a yeast strains carrying the deletion of a unique open reading frame, we will trans...

M. Brown J. A. Brown

2005-01-01

381

Functional selection for the centromere DNA from yeast chromosome VIII.  

PubMed Central

Centromeres are essential components of eucaryotic chromosomes. In budding yeast, up to now, 15 of the 16 centromere DNAs have been isolated. Here we report the functional isolation and characterization of CEN8, the last of the yeast centromeres missing. The centromere consensus sequence for the 16 chromosomes in this organism is presented. Images

Fleig, U; Beinhauer, J D; Hegemann, J H

1995-01-01

382

Arxula adeninivorans , a yeast assimilating many nitrogenous and aromatic compounds  

Microsoft Academic Search

A detailed description of the yeast species Arxula adeninivorans (syn. Trichosporon adeninovorans) was given. The yeast assimilated all the suggars, polyalcohols and organic acids used in the conventional carbon compound assimilation test rapidly, except for L-rhamnose, inulin, lactose, lactate and methanol. As nitrogen sources served all conventionally used compounds except creatine and creatinine. Several nitrogenous compounds, e.g. amino acids, purine

Wouter J. Middelhoven; Ilona M. de Jong; Marleen de Winter

1991-01-01

383

Exploring the Ubiquitin-Proteasome Protein Degradation Pathway in Yeast  

ERIC Educational Resources Information Center

This article describes an undergraduate biochemistry laboratory investigating the ubiquitin-proteasome pathway in yeast. In this exercise, the enzyme beta-galactosidase (beta-gal) is expressed in yeast under the control of a stress response promoter. Following exposure to heat stress to induce beta-gal expression, cycloheximide is added to halt…

Will, Tamara J.; McWatters, Melissa K.; McQuade, Kristi L.

2006-01-01

384

Mathematical model for aerobic culture of a recombinant yeast  

Microsoft Academic Search

A mathematical model was formulated to simulate cell growth, plasmid loss and recombinant protein production during the aerobic culture of a recombinant yeast S. cerevisiae. Model development was based on three simplified metabolic events in the yeast: glucose fermentation, glucose oxidation and ethanol oxidation. Cell growth was expressed as a composite of these metabolic events. Their contributions to the total

Z. Zhang; J. M. Scharer; M. Moo-Young

1997-01-01

385

Modelling of the alcohol dehydrogenase production in baker's yeast  

Microsoft Academic Search

A mathematical model was formulated to simulate cell growth and enzyme production during the aerobic and micro-aerobic culture of the yeast Saccharomyces cerevisiae. Model development was based on three simplified metabolic events in the yeast: glucose fermentation, glucose oxidation and ethanol oxidation. Cell growth was expressed as a composite of these metabolic events. Their contributions to the total specific growth

A. Vrsalovi? Prese?ki; ?. Vasi?-Ra?ki

2005-01-01

386

A microfluidic chemostat for experiments with bacterial and yeast cells  

Microsoft Academic Search

Bacteria and yeast frequently exist as populations capable of reaching extremely high cell densities. With conventional culturing techniques, however, cell proliferation and ultimate density are limited by depletion of nutrients and accumulation of metabolites in the medium. Here we describe design and operation of microfabricated elastomer chips, in which chemostatic conditions are maintained for bacterial and yeast colonies growing in

Caroline Lobo; HoJung Cho; J Kyle Campbell; Yann S Dufour; Ann M Stevens; Alex Groisman; Andre Levchenko

2005-01-01

387

A method for plasmid purification directly from yeast  

Microsoft Academic Search

A rapid technique for purifying plasmids from yeast Saccharomyces cerevisiae is described that yields high-quality DNA suitable for bacterial transformation, yeast transformation, and direct DNA sequencing. The method requires only small culture volumes and proprietary bacterial plasmid miniprep kits that allow one to simultaneously prepare a large number of samples in a very short period of time while avoiding the

Madhu V. Singh; P. Anthony Weil

2002-01-01

388

Aerobic sugar metabolism in the spoilage yeast Zygosaccharomyces bailii  

Microsoft Academic Search

Despite the importance of some Zygosaccharomyces species as agents causing spoilage of food, the carbon and energy metabolism of most of them is yet largely unknown. This is the case with Zygosaccharomyces bailii. In this study the occurrence of the Crabtree effect in the petite-negative yeast Z. bailii ATCC 36947 was investigated. In this yeast the aerobic ethanol production is

Annamaria Merico; Daniele Capitanio; Ileana Vigentini; Bianca Maria Ranzi; Concetta Compagno

2003-01-01

389

The natural history of yeast prions.  

PubMed

Although prions were first discovered through their link to severe brain degenerative diseases in animals, the emergence of prions as regulators of the phenotype of the yeast Saccharomyces cerevisiae and the filamentous fungus Podospora anserina has revealed a new facet of prion biology. In most cases, fungal prions are carried without apparent detriment to the host cell, representing a novel form of epigenetic inheritance. This raises the question of whether or not yeast prions are beneficial survival factors or actually gives rise to a "disease state" that is selected against in nature. To date, most studies on the impact of fungal prions have focused on laboratory-cultivated "domesticated" strains of S. cerevisiae. At least eight prions have now been described in this species, each with the potential to impact on a wide range of cellular processes. The discovery of prions in nondomesticated strains of S. cerevisiae and P. anserina has confirmed that prions are not simply an artifact of "domestication" of this species. In this review, I describe what we currently know about the phenotypic impact of fungal prions. I then describe how the interplay between host genotype and the prion-mediated changes can generate a wide array of phenotypic diversity. How such prion-generated diversity may be of benefit to the host in survival in a fluctuating, often hazardous environment is then outlined. Prion research has now entered a new phase in which we must now consider their biological function and evolutionary significance in the natural world. PMID:23763759

Tuite, Mick F

2013-01-01

390

Mechanics of cell division in fission yeast  

NASA Astrophysics Data System (ADS)

Cytokinesis is the stage of cell division in which a cell divides into two. A paradigm of cytokinesis in animal cells is that the actomyosin contractile ring provides the primary force to squeeze the cell into two. In the fission yeast Schizosaccharomyces pombe, cytokinesis also requires a actomyosin ring, which has been generally assumed to provide the force for cleavage. However, in contrast to animal cells, yeast cells assemble a cell wall septum concomitant with ring contraction and possess large (MPa) internal turgor pressure. Here, we show that the inward force generated by the division apparatus opposes turgor pressure; a decrease in effective turgor pressure leads to an increase in cleavage rate. We show that the ring cannot be the primary force generator. Scaling arguments indicate that the contractile ring can only provide a tiny fraction of the mechanical stress required to overcome turgor. Further, we show that cleavage can occur even in the absence of the contractile ring. Instead of the contractile ring, scaling arguments and modeling suggest that the large forces for cytokinesis are produced by the assembly of cell wall polymers in the growing septum.

Chang, Fred

2012-02-01

391

Perfect and Imperfect Nucleosome Positioning in Yeast  

PubMed Central

Numerous studies of nucleosome positioning have shown that nucleosomes almost invariably adopt one of several alternative overlapping positions on a short DNA fragment in vitro. We define such a set of overlapping positions as a "position cluster", and the 5S RNA gene positioning sequence is presented as an example. The notable exception is the synthetic 601-sequence, which can position a nucleosome perfectly in vitro, though not in vivo. Many years ago, we demonstrated that nucleosome position clusters are present on the CUP1 and HIS3 genes in native yeast chromatin. Recently, using genome-wide paired-end sequencing of nucleosomes, we have shown that position clusters are the general rule in yeast chromatin, not the exception. We argue that, within a cell population, one of several alternative nucleosomal arrays is formed on each gene. We show how position clusters and alternative arrays can give rise to typical nucleosome occupancy profiles, and that position clusters are disrupted by transcriptional activation. The centromeric nucleosome is a rare example of perfect positioning in vivo. It is, however, a special case, since it contains the centromeric histone H3 variant instead of normal H3. Perfect positioning might be due to centromeric sequence-specific DNA binding proteins. Finally, we point out that the existence of position clusters implies that the putative nucleosome code is degenerate. We suggest that degeneracy might be a crucial point in the debate concerning the code.

Cole, Hope A.; Nagarajavel, V.; Clark, David J.

2012-01-01

392

Production of baker's yeast using date juice.  

PubMed

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 degrees C, 1.4 vvm aeration rate and agitation of 500 r/min. PMID:17822056

Beiroti, A; Hosseini, S N

2007-07-01

393

Thermodynamic study of yeast phosphoglycerate kinase.  

PubMed

Enthalpies of binding of MgADP, MgATP, and 3-phosphoglycerate to yeast phosphoglycerate kinase have been determined by flow calorimetry at 9.95-32.00 degrees C. Combination of these data with published dissociation constants [Scopes, R.K. (1978) Eur. J. Biochem. 91, 119-129] yielded the following thermodynamic parameters for the binding of 3-phosphoglycerate at 25 degrees C: delta Go = -6.76 +/- 0.11 kcal mol-1, delta H = 3.74 +/- 0.08 kcal mol-1, delta So = 35.2 +/- 0.6 cal K-1 mol-1, and delta Cp = 0.12 +/- 0.32 kcal K-1 mol-1. The thermal unfolding of phosphoglycerate kinase in the absence and presence of the ligands listed above was studied by differential scanning calorimetry. The temperature of half-completion, t 1/2, of the denaturation and the denaturational enthalpy are increased by the binding of the ligands, the increase in t 1/2 being a manifestation of Le Chatelier's principle and that in enthalpy reflecting the enthalpy of dissociation of the ligand. Only one denaturational peak was observed under all conditions, and in contrast with the case of yeast hexokinase [Takahashi, K., Casey, J.L., & Sturtevant, J.M. (1981) Biochemistry 20, 4693-4697], no definitive evidence for the unfolding of more than one domain was obtained. PMID:3548815

Hu, C Q; Sturtevant, J M

1987-01-13

394

Phosphorylation-dephosphorylation of yeast pyruvate dehydrogenase  

SciTech Connect

Pyruvate dehydrogenase complex (PDC) was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). No pyruvate dehydrogenase (PDH) kinase activity was detected at any stage of the purification. However, the purified PDC was phosphorylated and inactivated by purified PDH kinase from bovine kidney mitochondria, Mg/sup 2 +/, and (..gamma..-/sup 32/P)ATP. The protein-bound radioactivity was localized in the PDH ..cap alpha.. subunit. The phosphorylated, inactivated PDC was dephosphorylated and reactivated with purified bovine PDH phosphatase, Mg/sup 2 +/, and Ca/sup 2 +/. From a tryptic digest of phosphorylated yeast PDC a radioactive peptide was isolated by anion and reverse phase HPLC. The sequence of this tetradecapeptide is Tyr-Gly-Gly-His-Ser(P)-Met-Ser-Asp-Pro-Gly-Thr-Thr-Tyr-Arg. This sequence is very similar to the sequence of a tryptic phosphopeptide derived from the ..cap alpha.. subunit of bovine kidney and heart PDH: Tyr-His-Gly-His-Ser(P)-Met-Ser-Asp-Pro-Gly-Val-Ser-Tyr-Arg.

Uhlinger, D.J.; Reed, L.J.

1986-05-01

395

The Architecture of Yeast DNA Polymerase ?.  

PubMed

DNA polymerase ? (Pol?) is specialized for the extension step of translesion DNA synthesis (TLS). Despite its central role in maintaining genome integrity, little is known about its overall architecture. Initially identified as a heterodimer of the catalytic subunit Rev3 and the accessory subunit Rev7, yeast Pol? has recently been shown to form a stable four-subunit enzyme (Pol?-d) upon the incorporation of Pol31 and Pol32, the accessory subunits of yeast Pol?. To understand the 3D architecture and assembly of Pol? and Pol?-d, we employed electron microscopy. We show here how the catalytic and accessory subunits of Pol? and Pol?-d are organized relative to each other. In particular, we show that Pol?-d has a bilobal architecture resembling the replicative polymerases and that Pol32 lies in proximity to Rev7. Collectively, our study provides views of Pol? and Pol?-d and a structural framework for understanding their roles in DNA damage bypass. PMID:24120860

Gómez-Llorente, Yacob; Malik, Radhika; Jain, Rinku; Choudhury, Jayati Roy; Johnson, Robert E; Prakash, Louise; Prakash, Satya; Ubarretxena-Belandia, Iban; Aggarwal, Aneel K

2013-10-10

396

Nucleotide degradation and ribose salvage in yeast.  

PubMed

Nucleotide degradation is a universal metabolic capability. Here we combine metabolomics, genetics and biochemistry to characterize the yeast pathway. Nutrient starvation, via PKA, AMPK/SNF1, and TOR, triggers autophagic breakdown of ribosomes into nucleotides. A protein not previously associated with nucleotide degradation, Phm8, converts nucleotide monophosphates into nucleosides. Downstream steps, which involve the purine nucleoside phosphorylase, Pnp1, and pyrimidine nucleoside hydrolase, Urh1, funnel ribose into the nonoxidative pentose phosphate pathway. During carbon starvation, the ribose-derived carbon accumulates as sedoheptulose-7-phosphate, whose consumption by transaldolase is impaired due to depletion of transaldolase's other substrate, glyceraldehyde-3-phosphate. Oxidative stress increases glyceraldehyde-3-phosphate, resulting in rapid consumption of sedoheptulose-7-phosphate to make NADPH for antioxidant defense. Ablation of Phm8 or double deletion of Pnp1 and Urh1 prevent effective nucleotide salvage, resulting in metabolite depletion and impaired survival of starving yeast. Thus, ribose salvage provides means of surviving nutrient starvation and oxidative stress. PMID:23670538

Xu, Yi-Fan; Létisse, Fabien; Absalan, Farnaz; Lu, Wenyun; Kuznetsova, Ekaterina; Brown, Greg; Caudy, Amy A; Yakunin, Alexander F; Broach, James R; Rabinowitz, Joshua D

2013-05-14

397

[PSI+] Prion Variant Establishment in Yeast  

PubMed Central

Summary Differences in the clinical pathology of mammalian prion diseases reflect distinct heritable conformations of aggregated PrP proteins, called prion strains. Here, using the yeast [PSI+] prion, we examine the de novo establishment of prion strains (called variants in yeast). The [PSI+] prion protein, Sup35, is efficiently induced to take on numerous prion variant conformations following transient overexpression of Sup35 in the presence of another prion, e.g. [PIN+]. One hypothesis is that the first [PSI+] prion seed to arise in a cell causes propagation of only that seed’s variant, but that different variants could be initiated in different cells. However, we now show that even within a single cell, Sup35 retains the potential to fold into more than one variant type. When individual cells segregating different [PSI+] variants were followed in pedigrees, establishment of a single variant phenotype generally occurred in daughters, granddaughters or great granddaughters—but in 5% of the pedigrees cells continued to segregate multiple variants indefinitely. The data is consistent with the idea that many newly formed prions go through a maturation phase before they reach a single specific variant conformation. These findings may be relevant to mammalian PrP prion strain establishment and adaptation.

Sharma, Jaya; Liebman, Susan W.

2012-01-01

398

Stationary phase in the yeast Saccharomyces cerevisiae.  

PubMed Central

Growth and proliferation of microorganisms such as the yeast Saccharomyces cerevisiae are controlled in part by the availability of nutrients. When proliferating yeast cells exhaust available nutrients, they enter a stationary phase characterized by cell cycle arrest and specific physiological, biochemical, and morphological changes. These changes include thickening of the cell wall, accumulation of reserve carbohydrates, and acquisition of thermotolerance. Recent characterization of mutant cells that are conditionally defective only for the resumption of proliferation from stationary phase provides evidence that stationary phase is a unique developmental state. Strains with mutations affecting entry into and survival during stationary phase have also been isolated, and the mutations have been shown to affect at least seven different cellular processes: (i) signal transduction, (ii) protein synthesis, (iii) protein N-terminal acetylation, (iv) protein turnover, (v) protein secretion, (vi) membrane biosynthesis, and (vii) cell polarity. The exact nature of the relationship between these processes and survival during stationary phase remains to be elucidated. We propose that cell cycle arrest coordinated with the ability to remain viable in the absence of additional nutrients provides a good operational definition of starvation-induced stationary phase.

Werner-Washburne, M; Braun, E; Johnston, G C; Singer, R A

1993-01-01

399

Nanomechanics of Yeast Surfaces Revealed by AFM  

NASA Astrophysics Data System (ADS)

Despite the large and well-documented characterization of the microbial cell wall in terms of chemical composition, the determination of the mechanical properties of surface molecules in relation to their function remains a key challenge in cell biology.The emergence of powerful tools allowing molecular manipulations has already revolutionized our understanding of the surface properties of fungal cells. At the frontier between nanophysics and molecular biology, atomic force microscopy (AFM), and more specifically single-molecule force spectroscopy (SMFS), has strongly contributed to our current knowledge of the cell wall organization and nanomechanical properties. However, due to the complexity of the technique, measurements on live cells are still at their infancy.In this chapter, we describe the cell wall composition and recapitulate the principles of AFM as well as the main current methodologies used to perform AFM measurements on live cells, including sample immobilization and tip functionalization.The current status of the progress in probing nanomechanics of the yeast surface is illustrated through three recent breakthrough studies. Determination of the cell wall nanostructure and elasticity is presented through two examples: the mechanical response of mannoproteins from brewing yeasts and elasticity measurements on lacking polysaccharide mutant strains. Additionally, an elegant study on force-induced unfolding and clustering of adhesion proteins located at the cell surface is also presented.

Dague, Etienne; Beaussart, Audrey; Alsteens, David

400

Alcohol-mediated haemolysis in yeast.  

PubMed

Although yeast are generally non-haemolytic, we have found that addition of alcohol vapour confers haemolytic properties on many strains of yeast and other fungi. We have called this phenomenon 'microbial alcohol-conferred haemolysis' (MACH). MACH is species- and strain-specific: whereas all six Candida tropicalis strains tested were haemolytic in the presence of ethanol, none among 10 C. glabrata strains tested exhibited this phenomenon. Among 27 C. albicans strains and 11 Saccharomyces cerevisiae strains tested, ethanol-mediated haemolysis was observed in 11 and 4 strains, respectively. Haemolysis is also dependent on the alcohol moiety: n-butanol and n-pentanol could also confer haemolysis, whereas methanol and 2-propanol did not. Haemolysis was found to be dependent on initial oxidation of the alcohol. Reduced haemolysis was observed in specific alcohol dehydrogenase mutants of both Aspergillus nidulans and S. cerevisiae. MACH was not observed during anaerobic growth, and was reduced in the presence of pararosaniline, an aldehyde scavenger. Results suggest that initial oxidation of the alcohol to the corresponding aldehyde is an essential step in the observed phenomenon. PMID:15565638

Shuster, Amir; Osherov, Nir; Rosenberg, Mel

2004-12-01

401

Copper transport in the yeast Saccharomyces cerevisiae  

SciTech Connect

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

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

1987-05-01

402

Sumoylation of the yeast Gcn5 protein.  

PubMed

Sumoylation, the process by which the ubiquitin-related SUMO protein is covalently attached to lysine side chains in other proteins, is involved in numerous processes in the eukaryotic cell, including transcriptional repression. In this study, we identify Gcn5, the histone-modifying subunit of the transcriptional regulatory complex SAGA, as a sumoylation substrate in yeast. In vitro, multiple sumoylation of recombinant Gcn5 alone or as a trimer with its interacting proteins Ada2 and Ada3 did not affect Gcn5's histone acetyltransferase (HAT) activity, suggesting that modification of Gcn5 with yeast SUMO (Smt3) may not directly regulate its HAT function. Through site-directed mutagenesis, the primary in vivo sumoylation site was identified as lysine-25, although an unsumoylatable K-to-R mutation of this residue led to no obvious in vivo effects. However, fusion of SUMO to the N-terminus of Gcn5 to mimic constitutive sumoylation resulted in defective growth on 3-aminotriazole media and reduced basal and activated transcription of the SAGA-dependent gene TRP3. Taken together with recent identification of multiple additional subunits of SAGA as sumoylated proteins in vivo, these data suggest that Gcn5 sumoylation may have an inhibitory role in transcriptional regulation. PMID:16411780

Sterner, David E; Nathan, Dafna; Reindle, Alison; Johnson, Erica S; Berger, Shelley L

2006-01-24

403

The cost of sexual signaling in yeast.  

PubMed

The handicap principle holds that costly sexual signals can reliably indicate mate quality. Only individuals of high quality can afford a strong signal--the cost of signaling is relatively lower for high-quality signalers than for low-quality signalers. This critical property is difficult to test experimentally because the benefit of signaling on mating success, and cost of signaling on other components of fitness, cannot easily be separated in obligate sexual organisms. We therefore studied the facultatively sexual yeast Saccharomyces cerevisiae, which produces pheromones to attract potential mates. To precisely measure the cost of signaling, the signal was reduced or removed by deleting one or both copies of the pheromone-encoding genes and measuring asexual growth rate in competition with a wild-type signaler. We manipulated signaler quality either by changing the quality of the assay environment or by changing the number of deleterious mutations carried. For both types of treatment, we found that the cost of signaling decreased as the quality of the signaler increased, demonstrating that the yeast pheromone signal has the key property required for selection under the handicap principle. We found that cells of high genetic quality produce stronger signals than low-quality cells, verifying that the signal is indeed honest. PMID:20584074

Smith, Carl; Greig, Duncan

2010-11-01

404

Yeast cell factories for fine chemical and API production  

PubMed Central

This review gives an overview of different yeast strains and enzyme classes involved in yeast whole-cell biotransformations. A focus was put on the synthesis of compounds for fine chemical and API (= active pharmaceutical ingredient) production employing single or only few-step enzymatic reactions. Accounting for recent success stories in metabolic engineering, the construction and use of synthetic pathways was also highlighted. Examples from academia and industry and advances in the field of designed yeast strain construction demonstrate the broad significance of yeast whole-cell applications. In addition to Saccharomyces cerevisiae, alternative yeast whole-cell biocatalysts are discussed such as Candida sp., Cryptococcus sp., Geotrichum sp., Issatchenkia sp., Kloeckera sp., Kluyveromyces sp., Pichia sp. (including Hansenula polymorpha = P. angusta), Rhodotorula sp., Rhodosporidium sp., alternative Saccharomyces sp., Schizosaccharomyces pombe, Torulopsis sp., Trichosporon sp., Trigonopsis variabilis, Yarrowia lipolytica and Zygosaccharomyces rouxii.

Pscheidt, Beate; Glieder, Anton

2008-01-01

405

Yeast cell factories for fine chemical and API production.  

PubMed

This review gives an overview of different yeast strains and enzyme classes involved in yeast whole-cell biotransformations. A focus was put on the synthesis of compounds for fine chemical and API (= active pharmaceutical ingredient) production employing single or only few-step enzymatic reactions. Accounting for recent success stories in metabolic engineering, the construction and use of synthetic pathways was also highlighted. Examples from academia and industry and advances in the field of designed yeast strain construction demonstrate the broad significance of yeast whole-cell applications. In addition to Saccharomyces cerevisiae, alternative yeast whole-cell biocatalysts are discussed such as Candida sp., Cryptococcus sp., Geotrichum sp., Issatchenkia sp., Kloeckera sp., Kluyveromyces sp., Pichia sp. (including Hansenula polymorpha = P. angusta), Rhodotorula sp., Rhodosporidium sp., alternative Saccharomyces sp., Schizosaccharomyces pombe, Torulopsis sp., Trichosporon sp., Trigonopsis variabilis, Yarrowia lipolytica and Zygosaccharomyces rouxii. PMID:18684335

Pscheidt, Beate; Glieder, Anton

2008-08-07

406

Evaluation of the Quantum II yeast identification system.  

PubMed Central

We compared three methods for identifying clinical yeast isolates: Abbott Quantum II, API 20C, and a modified BBL Minitek system. The API 20C and modified Minitek systems agreed on the identification of 243 of 245 yeasts (99.2%). The Quantum II system correctly identified 197 (80.4%), incorrectly identified 19 (7.8%), and did not identify 29 (11.8%) of the yeasts. Most of the misidentifications with the Quantum II occurred because assimilation or biochemical results were false-positive. Sixteen different species of yeasts and 16 different Quantum II substrates contributed to the discrepancies. On retesting with the Quantum II, 31% of the discrepant strains were correctly identified, while the remaining 69% were incorrectly identified or were not identified. Erroneous biochemical and assimilation results were also noted with yeasts that were correctly identified by the Quantum II system.

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

1985-01-01

407

Genetic and phenotypic characteristics of baker's yeast: relevance to baking.  

PubMed

Yeasts rarely encounter ideal physiological conditions during their industrial life span; therefore, their ability to adapt to changing conditions determines their usefulness and applicability. This is especially true for baking strains of Saccharomyces cerevisiae. The success of this yeast in the ancient art of bread making is based on its capacity to rapidly transform carbohydrates into CO2 rather than its unusual resistance to environmental stresses. Moreover, baker's yeast must exhibit efficient respiratory metabolism during yeast manufacturing, which determines biomass yield. However, optimal growth conditions often have negative consequences in other commercially important aspects, such as fermentative power or stress tolerance. This article reviews the genetic and physiological characteristics of baking yeast strains, emphasizing the activation of regulatory mechanisms in response to carbon source and stress signaling and their importance in defining targets for strain selection and improvement. PMID:23464571

Randez-Gil, Francisca; Córcoles-Sáez, Isaac; Prieto, José A

2013-01-01

408

Lipid raft involvement in yeast cell growth and death  

PubMed Central

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

Mollinedo, Faustino

2012-01-01

409

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

PubMed

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

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

2013-04-17

410

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

PubMed Central

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

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

2013-01-01

411

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

NASA Astrophysics Data System (ADS)

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 (?+) 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" (?-), 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 ?+ cells (104) and mitochondria produced nearly symmetric, Gaussian distributions. The ?- cells (110) and mitochondria showed striking asymmetry and skew that appeared to follow a Poisson distribution.

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

2006-03-01

412

Three yeast proteins that specifically inhibit yeast proteases A, B, and C.  

PubMed Central

Baker's yeast was found to contain inhibitors of yeast proteases A and C. These two proteins were partially purified, characterized, and compared with the previously described inhibitor of protease B. The A and B inhibitors were very thermostable and were extracted from intact yeast cells at 9k C. The A inhibitor appeared to be a protein with a molecular weight of about 22,000 which could be dissociated into two monomers or chains, both of which had a molecular weight of approximately 11,000. The protease C (carboxypeptidase Y)-inhibitor complex was purified and then partially disociated on an ion-exchange column. The free protease C inhibitor was very unstable, possibly because of destruction by a contaminating protease. Each inhibitor was specific for its corresponding protease and each inhibition was competitive. Whereas proteases A, B, and C destroyed the B inhibitor, only protease B had a pronounced destructive effect on the protease A inhibitor. Pepstatin was found to be a selective inhibitor of protease A, whereas chymostatin and antipain specifically inhibited protease B. Images

Lenney, J F

1975-01-01

413

Systematic identification of yeast proteins extracted into model wine during aging on the yeast lees.  

PubMed

Total protein and protein-associated mannan concentrations were measured, and individual proteins were identified during extraction into model wines over 9 months of aging on the yeast lees following completion of fermentations by seven wine strains of Saccharomyces cerevisiae. In aged wines, protein-associated mannan increased about 6-fold (+/-66%), while total protein only increased 2-fold (+/-20%), which resulted in a significantly greater protein-associated mannan/total protein ratio for three strains. A total of 219 proteins were identified among all wine samples taken over the entire time course. Of the 17 "long-lived" proteins detected in all 9 month samples, 13 were cell wall mannoproteins, and four were glycolytic enzymes. Most cytosolic proteins were not detected after 6 months. Native mannosylated yeast invertase was assayed for binding to wine tannin and was found to have a 10-fold lower affinity than nonglycosylated bovine serum albumin. Enrichment of mannoproteins in the aged model wines implies greater solution stability than other yeast proteins and the possibility that their contributions to wine quality may persist long after bottling. PMID:20108898

Rowe, Jeffrey D; Harbertson, James F; Osborne, James P; Freitag, Michael; Lim, Juyun; Bakalinsky, Alan T

2010-02-24

414

[Studies on the yeasts and yeast-like fungi degrading trinitrotoluene].  

PubMed

Seventeen strains of yeasts and yeast-like fungi were isolated from soil and waste water samples polluted by trinitrotoluene (TNT). These strains can degrade 71%-93% TNT when growing in the medium originally containing 70-80 mg/L TNT within 40 h. They were identified. Among them, six strains are Candida krusei, four are C. quercitrusa, one is C. famata, one is Hansenula beijerinckii, one is H. subpelliculosa, and four are Geotrichum candidum. Six strains were selected for further studies on the conditions effecting TNT degradation by them. The optimum pH and temperature are pH 7 and 37-40 degrees C, respectively. TNT Degradation ability of the strains can be promoted by adding 0.01%-0.05% glucose or 0.01%-0.1% yeast extract into the medium. Addition of 0.05% (NH4)2SO4 or NH4Cl to the medium can evidently inhibit the degradation of TNT by the strains. PMID:12549418

Yin, P; Bai, F; Zhou, P

1998-08-01

415

Phyllosphere yeasts rapidly break down biodegradable plastics  

PubMed Central

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

2011-01-01

416

Enzymatic activity of immobilized yeast phosphoglycerate kinase.  

PubMed

This work reports the first evidence that recombinant yeast phosphoglycerate kinase (PGK) is still significantly active when immobilized on glass and muscovite mica. Using previous work to improve the sensitivity of the existing setup, Tapping Mode atomic force microscopy (AFM) was used in a liquid environment to determine the surface enzyme coverage of derivatized mica and glass slides. When associated to spectrophotometric measurements, the AFM data allows assessing the catalytic constant of surface enzymes and comparing it to bulk values. The validity of the Michaelis-Menten model for surface reactions is discussed, supported by spectroscopic measurements of the surface consumption of 1,3-bis-phosphoglycerate (1,3-BPG). Only a few percent of the enzyme material maintains its initial bulk activity. This value could constitute a guideline for biosensors made with the method used here whenever a rapid assessment of the remaining surface activity is needed. PMID:17045469

Hurth, Cedric; Tassius, Chantal; Talbot, Jean-Claude; Maali, Abdelhamid; Moskalenko, Cendrine; Minard, Philippe; Aimé, Jean-Pierre; Argoul, Françoise

2006-10-11

417

Immunosuppressive decalin derivatives from red yeast rice.  

PubMed

Five new decalin derivatives (1-5), together with two known compounds (6 and 7), were isolated from the ethyl acetate extract of red yeast rice. Their structures were elucidated by means of NMR and mass spectroscopic analyses. Monascusic lactone A (1) is the first reported naturally occurring decalin derivative possessing a spiro lactone at the C-1 position. The immunosuppressive effects of all these isolates (1-7) on human T cell proliferation were investigated, and all, especially monascusic acids B (2), C (3), D (4), and A (6) and heptaketide (7), suppressed human T cell proliferation in a dose-dependent manner from 10 to 100 ?M. This is the first report on the immunosuppressive activity of decalin derivatives. PMID:22394155

Zhu, Lin; Lu, Jing-Guang; Li, Ting; Zhu, Guo-Yuan; Han, Quan-Bin; Hsiao, Wen-Luan; Liu, Liang; Jiang, Zhi-Hong

2012-03-06

418

A Detour for Yeast Oxysterol Binding Proteins*  

PubMed Central

Oxysterol binding protein-related proteins, including the yeast proteins encoded by the OSH gene family (OSH1–OSH7), are implicated in the non-vesicular transfer of sterols between intracellular membranes and the plasma membrane. In light of recent studies, we revisited the proposal that Osh proteins are sterol transfer proteins and present new models consistent with known Osh protein functions. These models focus on the role of Osh proteins as sterol-dependent regulators of phosphoinositide and sphingolipid pathways. In contrast to their posited role as non-vesicular sterol transfer proteins, we propose that Osh proteins coordinate lipid signaling and membrane reorganization with the assembly of tethering complexes to promote molecular exchanges at membrane contact sites.

Beh, Christopher T.; McMaster, Christopher R.; Kozminski, Keith G.; Menon, Anant K.

2012-01-01

419

Sporulation in the budding yeast Saccharomyces cerevisiae.  

PubMed

In response to nitrogen starvation in the presence of a poor carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and package the haploid nuclei produced in meiosis into spores. The formation of spores requires an unusual cell division event in which daughter cells are formed within the cytoplasm of the mother cell. This process involves the de novo generation of two different cellular structures: novel membrane compartments within the cell cytoplasm that give rise to the spore plasma membrane and an extensive spore wall that protects the spore from environmental insults. This article summarizes what is known about the molecular mechanisms controlling spore assembly with particular attention to how constitutive cellular functions are modified to create novel behaviors during this developmental process. Key regulatory points on the sporulation pathway are also discussed as well as the possible role of sporulation in the natural ecology of S. cerevisiae. PMID:22084423

Neiman, Aaron M

2011-11-01

420

Organic growth factor requirements of some yeasts.  

PubMed

Some sporogenous yeasts (Brettanomyces bruxellensis, Debaryomyces hansenii, Hansenula ciferrii, Hansenula polymorpha, Pichia polymorpha, Saccharomycopsis guttulata, and Saccharomyces chevalieri), isolated from various fruits have been examined for their organic growth factor requisites. H. ciferrii was completely deficient in thiamine, biotin, inositol, riboflavin, niacin, and partially deficient in pantothenic acid. It required an external supply of 0.1-1.0 ppm thiamine, 0.01-0.1 ppm biotin, 10.0 ppm inositol, 0.10 ppm niacin and riboflavin for its optimum growth. H. polymorpha showed partial deficiency only in xanthine. P. polymorpha gave indications of partial deficiencies in thiamine and biotin. S. guttulata was completely deficient in biotin, and partially deficient in adenine sulphate. It required 0.01 ppm biotin for optimum growth. S chevalieri was completely deficient in pyridoxine and partially deficient in thiamine. It required 0.1 ppm pyridoxine for maximum growth. D. hansenii and B bruxellensis were auxoautotrophic for the various growth factors studied. PMID:7242379

Madan, M; Gulati, N

1980-01-01

421

Biosynthesis of Crystalline Silver and Gold Nanoparticles by Extremophilic Yeasts  

PubMed Central

The biosynthesis of Ag and Au nanoparticles (NPs) was investigated using an extremophilic yeast strain isolated from acid mine drainage in Portugal. Three distinct studies were performed, namely, the growth of yeast strain in presence of metal ions, the use of yeast biomass for the metal nanoparticles synthesis, and of the supernatant obtained after 24-hour incubation of yeast biomass in water. The extremophilic strain under study was able to grow up to an Ag ion concentration of 1.5?mM whereas an increase of Au ion concentration over 0.09?mM caused a strong inhibitory effect. A successful route for the metal NPs synthesis was obtained using the yeast biomass. When the washed yeast cells were in contact with Ag or Au solutions, AgNPs smaller than 20?nm were produced, as for the AuNPs diameter ranged from 30 to 100?nm, as determined through transmission electron microscopy and confirmed by energy-dispersive X-ray spectra. The supernatant-based strategy provided evidence that proteins were released to the medium by the yeasts, which could be responsible for the formation and stabilisation of the Ag NPs, although the involvement of the cell wall seems fundamental for AuNPs synthesis.

Mourato, Ana; Gadanho, Mario; Lino, Ana R.; Tenreiro, Rogerio

2011-01-01

422

A1 toxicity in yeast. A role for Mg?  

PubMed

We have established conditions in which soluble Al is toxic to the yeast Saccharomyces cerevisiae. The major modifications to a standard synthetic medium were lowering the pH and the concentration of Mg ions. Alterations to the PO4, Ca, or K concentration had little effect on toxicity. Organic acids known to chelate Al reduced its toxicity, suggesting that Al3+ is the toxic Al species. The unique ability of Mg ions to ameliorate Al toxicity led us to investigate the hypothesis that Al inhibits Mg uptake by yeast. Yeast cells accumulate Mg, Co, Zn, Ni, and Mn ions via the same transport system (G.F. Fuhrmann, A. Rothstein [1968] Biochim Biophys Acta 163: 325-330). Al3+ inhibited the accumulation of 57Co2+ by yeast cells more effectively than Ga, La, or Mg. In addition, a mutant yeast strain with a defect in divalent cation uptake proved to be more sensitive to Al than a wild-type strain. Taken together, these results suggest that Al may cause Mg deficiency in yeast by blocking Mg transport. We discuss the relevance of yeast as a model for the study of Al toxicity in plant systems. PMID:8938412

MacDiarmid, C W; Gardner, R C

1996-11-01

423

A1 toxicity in yeast. A role for Mg?  

PubMed Central

We have established conditions in which soluble Al is toxic to the yeast Saccharomyces cerevisiae. The major modifications to a standard synthetic medium were lowering the pH and the concentration of Mg ions. Alterations to the PO4, Ca, or K concentration had little effect on toxicity. Organic acids known to chelate Al reduced its toxicity, suggesting that Al3+ is the toxic Al species. The unique ability of Mg ions to ameliorate Al toxicity led us to investigate the hypothesis that Al inhibits Mg uptake by yeast. Yeast cells accumulate Mg, Co, Zn, Ni, and Mn ions via the same transport system (G.F. Fuhrmann, A. Rothstein [1968] Biochim Biophys Acta 163: 325-330). Al3+ inhibited the accumulation of 57Co2+ by yeast cells more effectively than Ga, La, or Mg. In addition, a mutant yeast strain with a defect in divalent cation uptake proved to be more sensitive to Al than a wild-type strain. Taken together, these results suggest that Al may cause Mg deficiency in yeast by blocking Mg transport. We discuss the relevance of yeast as a model for the study of Al toxicity in plant systems.

MacDiarmid, C W; Gardner, R C

1996-01-01

424

The beetle gut: a hyperdiverse source of novel yeasts  

PubMed Central

We isolated over 650 yeasts over a three year period from the gut of a variety of beetles and characterized them on the basis of LSU rDNA sequences and morphological and metabolic traits. Of these, at least 200 were undescribed taxa, a number equivalent to almost 30% of all currently recognized yeast species. A Bayesian analysis of species discovery rates predicts further sampling of previously sampled habitats could easily produce another 100 species. The sampled habitat is, thereby, estimated to contain well over half as many more species as are currently known worldwide. The beetle gut yeasts occur in 45 independent lineages scattered across the yeast phylogenetic tree, often in clusters. The distribution suggests that the some of the yeasts diversified by a process of horizontal transmission in the habitats and subsequent specialization in association with insect hosts. Evidence of specialization comes from consistent associations over time and broad geographical ranges of certain yeast and beetle species. The discovery of high yeast diversity in a previously unexplored habitat is a first step toward investigating the basis of the interactions and their impact in relation to ecology and evolution.

SUH, Sung-Oui; McHUGH, Joseph V.; POLLOCK, David D.; BLACKWELL, Meredith

2010-01-01

425

Yeast responses to stresses associated with industrial brewery handling.  

PubMed

During brewery handling, production strains of yeast must respond to fluctuations in dissolved oxygen concentration, pH, osmolarity, ethanol concentration, nutrient supply and temperature. Fermentation performance of brewing yeast strains is dependent on their ability to adapt to these changes, particularly during batch brewery fermentation which involves the recycling (repitching) of a single yeast culture (slurry) over a number of fermentations (generations). Modern practices, such as the use of high-gravity worts and preparation of dried yeast for use as an inoculum, have increased the magnitude of the stresses to which the cell is subjected. The ability of yeast to respond effectively to these conditions is essential not only for beer production but also for maintaining the fermentation fitness of yeast for use in subsequent fermentations. During brewery handling, cells inhabit a complex environment and our understanding of stress responses under such conditions is limited. The advent of techniques capable of determining genomic and proteomic changes within the cell is likely vastly to improve our knowledge of yeast stress responses during industrial brewery handling. PMID:17645521

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

2007-07-20

426

SUCROSE INVERSION BY BAKERS' YEAST AS A FUNCTION OF TEMPERATURE  

PubMed Central

Inversion of sucrose by bakers' yeast follows the same course as inversion catalyzed by yeast invertase. Rate of inversion increases exponentially with temperature; the temperature characteristic in the Arrhenius equation is 10,700 below 13–17°C., and 8,300 above that temperature. Temperature inactivation occurs above 40°C. The effects of temperature upon rate of inversion were the same using Fleischmann's yeast cake, the same yeast killed with toluene, and a pure strain (G. M. No. 21062) of bakers' yeast. The last differed from the other two only in the fact that its critical temperature was 13°C. as compared with 17°C. for the others. The catalytic inversion is associated with enzyme activity inside the cell, not in the medium, and is independent of any vital processes inside the cell such as respiration and fermentation. Since invertase activity is the same inside the cell as it is after extraction, it appears possible to relate the temperature characteristics for physiological processes to the catalytic chemical systems which determine their rate. At least two enzymes are capable of inverting sucrose in the yeast cell. The familiar yeast invertase (µ = 10,700) is active below 13–17°C. while a second enzyme (M = 8,300) plays the dominant role above that temperature.

Sizer, Irwin W.

1938-01-01

427

Effects of live and autoclaved yeast cultures on ruminal fermentation in vitro  

Microsoft Academic Search

The objective of this study is to determine whether a yeast culture of Saccharomyces cerevisiae has an effect on parameters of ruminal fermentation and whether the potential positive effects of yeast culture are associated with the yeast's viability. For this purpose, live and autoclaved yeast cultures were tested simultaneously in the rumen simulation technique (Rusitec). Each fermentation vessel received daily

H. Oeztuerk

428

High-Frequency Transformation of Yeast: Autonomous Replication of Hybrid DNA Molecules  

Microsoft Academic Search

A set of vector DNAs (Y vectors) useful for the cloning of DNA fragments in Saccharomyces cerevisiae (yeast) and in Escherichia coli are characterized. With these vectors, three modes of yeast transformation are defined. (i) Vectors containing yeast chromosomal DNA sequences (YIp1, YIp5) transform yeast cells at low frequency (1-10 colonies per mu g) and integrate into the genome by

Kevin Struhl; Dan T. Stinchcomb; Stewart Scherer; Ronald W. Davis

1979-01-01

429

Effect of temperature on in vitro ochratoxin A biosorption onto yeast cell wall derivatives  

Microsoft Academic Search

In vitro biosorption of ochratoxin A (OA) onto three yeast industry products: a vinasse containing yeast cell walls (EX16), a purified yeast beta glucan (BETA) and a yeast cell wall fraction (LEC), has been studied as a function of the temperature. Equilibrium binding assays were performed from 4 to 37°C. The best models for OA biosorption onto EX16, BETA and

Diana Ringot; Benoit Lerzy; Jean Paul Bonhoure; Eric Auclair; Eric Oriol; Yvan Larondelle

2005-01-01

430

Influence of yeast drying process on different lager brewing strains viability  

Microsoft Academic Search

The potential for the application active dry yeast within brewing industry is supported by the advantages this type of yeast offers. Dried yeast is more robust and stable for transportation, distribution and storage. Further, there is no requirement for skilled laboratory staff as there is for yeast supplied on slope. During the drying process though, performed at high temperatures, a

Irina C. Bolat; Maria Turtoi; Michael C. Walsh

431

Performance of CHROMAGAR candida and BIGGY agar for identification of yeast species  

Microsoft Academic Search

BACKGROUND: The importance of identifying the pathogenic fungi rapidly has encouraged the development of differential media for the presumptive identification of yeasts. In this study two differential media, CHROMagar Candida and bismuth sulphite glucose glycine yeast agar, were evaluated for the presumptive identification of yeast species. METHODS: A total number of 270 yeast strains including 169 Candida albicans, 33 C.

Mine Yücesoy; Serhat Marol

2003-01-01

432

Production of Dairy-Based, Natural Sulphur Flavor Concentrate by Yeast Fermentation  

Microsoft Academic Search

Production of sulphur flavor concentrate by yeast fermentation was investigated using dairy media (milk and cream) spiked with L-methionine. The yeasts studied included so-called dairy yeasts Candida kefyr, Kluyveromyces marxianus, Debaryomyces hansenii, Geotrichum candidum, and Yarrowia lipolytica as well as wine yeasts Saccharomyces cerevisiae and Saccharomyces bayanus. Methionol was produced as the predominant volatile sulphur flavor compound. Other volatile sulphur

S.-Q. Liu; V. L. Crow

2010-01-01

433

Trehalose and glycogen in wine-making yeasts: methodological aspects and variability  

Microsoft Academic Search

Trehalose and glycogen, which can represent up to 30% of wine yeasts, was evaluated by different methods in (i) yeasts during fermentation of musts (200 g sugar l-1) and (ii) active dry yeasts. Fermentation trials demonstrated the potential value of monitoring changes in trehalose concentration during the rehydration step so that the performance of the yeasts can be evaluated.

Jean-Louis Roustan; Jean-Marie Sablayrolles

2002-01-01

434

Imaging real-time gene expression in living yeast.  

PubMed

INTRODUCTIONThis protocol describes the application of the MS2 system to the yeast Saccharomyces cerevisiae. ASH1 mRNA tagged with six MS2 repeats (6MBSs) is used to follow the localization of the ASH1 mRNA particles to the bud tip of a haploid yeast cell. W303 yeast cells transformed with pG14-MS2-GFP and pGAL-lacZ-MS2-ASH1 are grown on select medium lacking tryptophan and leucine. RNA expression is induced by the addition of galactose, and a time-lapse movie is then acquired. PMID:21356978

Zenklusen, Daniel; Wells, Amber L; Condeelis, John S; Singer, Robert H

2007-11-01

435

Regulation of yeast replicative life span by thiol oxidoreductases  

PubMed Central

Thiol-based redox reactions are involved in the regulation of a variety of biological functions, such as protection against oxidative stress, signal transduction and protein folding. Some proteins involved in redox regulation have been shown to modulate life span in organisms from yeast to mammals. To assess the role of thiol oxidoreductases in aging on a genome-wide scale, we analyzed the replicative life span of yeast cells lacking known and candidate thiol oxidoreductases. The data suggest the role of several pathways in regulation of yeast aging, including thioredoxin reduction, protein folding and degradation, peroxide reduction, PIP3 signaling, and ATP synthesis.

Hacioglu, Elise; Esmer, Isil; Fomenko, Dmitri E.; Gladyshev, Vadim N.; Koc, Ahmet

2011-01-01

436

Gas bubble formation in the cytoplasm of a fermenting yeast.  

PubMed

Current paradigms assume that gas bubbles cannot be formed within yeasts although these workhorses of the baking and brewing industries vigorously produce and release CO(2) gas. We show that yeasts produce gas bubbles that fill a significant part of the cell. The missing link between intracellular CO(2) production by glycolysis and eventual CO(2) release from cells has therefore been resolved. Yeasts may serve as model to study CO(2) behavior under pressurized conditions that may impact on fermentation biotechnology. PMID:23020660

Swart, Chantel W; Dithebe, Khumisho; Pohl, Carolina H; Swart, Hendrik C; Coetsee, Elizabeth; van Wyk, Pieter W J; Swarts, Jannie C; Lodolo, Elizabeth J; Kock, Johan L F

2012-10-01

437

Yeast Cells Respire, Too (But Not Like Me and You)  

NSDL National Science Digital Library

Students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Each student adds a small amount of baking yeast to a test tube filled with diluted molasses. A second, smaller test tube is then placed upside-down inside the solution. As the yeast cells respire, the carbon dioxide they produce is trapped inside the inverted test tube, producing a growing bubble of gas that is easily observed and measured. Students are presented with the procedure for designing an effective experiment; they learn to think critically about experimental results and indirect observations of experimental events.

Engineering K-Ph.d. Program

438

A yeast screen system for aromatase inhibitors and ligands for androgen receptor: yeast cells transformed with aromatase and androgen receptor.  

PubMed Central

Endocrine disruptors are hormone mimics that modify hormonal action in humans and animals. It is thought that some endocrine disruptors modify estrogen and androgen action in humans and animals by suppressing aromatase activity. Aromatase cytochrome P450 is the key enzyme that converts C19 androgens to aromatic C18 estrogenic steroids. We have developed a novel aromatase inhibitor screening method that allows us to identify antiaromatase activity of various environmental chemicals. The screen was developed by coexpressing the human aromatase and the mouse androgen receptor in yeast cells, which carry the androgen-responsive ss-galactosidase reporter plasmid. Functional expression of aromatase in yeast has been demonstrated using the [3H]-water release assay with intact cells as well as with yeast microsomes. The aromatase activity could be blocked by known aromatase inhibitors such as aminoglutethimide (AG). Yeast-produced androgen receptors were able to transactivate a yeast basal promoter linked to an androgen-responsive element in response to androgens. The resultant triple yeast transformant responded to the treatment of testosterone, androstenedione, or 5 alpha-dihydrotestosterone (5 alpha-DHT). In the absence of the aromatase inhibitor AG, transcriptional activation was observed only for the nonaromatizable androgen 5 alpha-DHT. However, the two aromatizable androgens (testosterone and androstenedione) induced the reporter activity in the presence of AG. Using this yeast-based assay, we confirmed that two flavones, chrysin and alpha-naphtholflavone, are inhibitors of aromatase. Thus, this yeast system allows us to develop a high-throughput screening method, without using radioactive substrate, to identify aromatase inhibitors as well as new ligands (nonaromatizable androgen mimics) for the androgen receptors. In addition, this screening method also allows us to distinguish nonandrogenic aromatase inhibitors from inhibitors with androgenic activity. This yeast screening method will be useful to screen environmental chemicals for their antiaromatase activity and for their interaction with androgen receptor. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Mak, P; Cruz, F D; Chen, S

1999-01-01

439

A panoramic view of yeast noncoding RNA processing.  

PubMed

Predictive analysis using publicly available yeast functional genomics and proteomics data suggests that many more proteins may be involved in biogenesis of ribonucleoproteins than are currently known. Using a microarray that monitors abundance and processing of noncoding RNAs, we analyzed 468 yeast strains carrying mutations in protein-coding genes, most of which have not previously been associated with RNA or RNP synthesis. Many strains mutated in uncharacterized genes displayed aberrant noncoding RNA profiles. Ten factors involved in noncoding RNA biogenesis were verified by further experimentation, including a protein required for 20S pre-rRNA processing (Tsr2p), a protein associated with the nuclear exosome (Lrp1p), and a factor required for box C/D snoRNA accumulation (Bcd1p). These data present a global view of yeast noncoding RNA processing and confirm that many currently uncharacterized yeast proteins are involved in biogenesis of noncoding RNA. PMID:12837249

Peng, Wen Tao; Robinson, Mark D; Mnaimneh, Sanie; Krogan, Nevan J; Cagney, Gerard; Morris, Quaid; Davierwala, Armaity P; Grigull, Jörg; Yang, Xueqi; Zhang, Wen; Mitsakakis, Nicholas; Ryan, Owen W; Datta, Nira; Jojic, Vladimir; Pal, Chris; Canadien, Veronica; Richards, Dawn; Beattie, Bryan; Wu, Lani F; Altschuler, Steven J; Roweis, Sam; Frey, Brendan J; Emili, Andrew; Greenblatt, Jack F; Hughes, Timothy R

2003-06-27

440

Ethanol and thermotolerance in the bioconversion of xylose by yeasts  

Treesearch

Heat and ethanol stress adversely affect membrane integrity. These factors are particularly detrimental to xylose-fermenting yeasts ... Organisms with higher ethanol tolerance have ATPase activities with low pH optima and high affinity for ATP.

441

The role of mitochondria in yeast programmed cell death  

PubMed Central

Mammalian apoptosis and yeast programmed cell death (PCD) share a variety of features including reactive oxygen species production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid-induced PCD (AA-PCD) which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.

Guaragnella, Nicoletta; Zdralevic, Masa; Antonacci, Lucia; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

2012-01-01

442

21 CFR 172.898 - Bakers yeast glycan.  

Code of Federal Regulations, 2013 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2013-04-01

443

21 CFR 172.898 - Bakers yeast glycan.  

Code of Federal Regulations, 2010 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2010-01-01

444

21 CFR 172.325 - Bakers yeast protein.  

Code of Federal Regulations, 2013 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2013-04-01

445

21 CFR 172.325 - Bakers yeast protein.  

Code of Federal Regulations, 2010 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2010-01-01

446

21 CFR 172.325 - Bakers yeast protein.  

Code of Federal Regulations, 2010 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2009-04-01

447

21 CFR 172.898 - Bakers yeast glycan.  

Code of Federal Regulations, 2010 CFR

...c) The viable microbial content of the finished ingredient is: (1) Less than 10,000 organisms/gram by aerobic plate count. (2) Less than 10 yeasts and molds/gram. (3) Negative for Salmonella, E. coli, coagulase...

2009-04-01

448

The Benefits of Humanized Yeast Models to Study Parkinson's Disease  

PubMed Central

Over the past decade, the baker's yeast Saccharomyces cerevisiae has proven to be a useful model system to investigate fundamental questions concerning the pathogenic role of human proteins in neurodegenerative diseases such as Parkinson's disease (PD). These so-called humanized yeast models for PD initially focused on ?-synuclein, which plays a key role in the etiology of PD. Upon expression of this human protein in the baker's yeast Saccharomyces cerevisiae, the events leading to aggregation and the molecular mechanisms that result in cellular toxicity are faithfully reproduced. More recently, a similar model to study the presumed pathobiology of the ?-synuclein interaction partner synphilin-1 has been established. In this review we will discuss recent advances using these humanized yeast models, pointing to new roles for cell wall integrity signaling, Ca2+ homeostasis, mitophagy, and the cytoskeleton.

Franssens, V.; Bynens, T.; Van den Brande, J.; Vandermeeren, K.; Verduyckt, M.; Winderickx, J.

2013-01-01

449

Polygalacturonase secreted by yeasts from Brazilian semi-arid environments.  

PubMed

Microbial pectinolytic enzymes are known to play a commercially important role in a number of industrial processes. The objective of this study was to investigate the extracellular polygalacturonases of yeasts isolated from Brazilian semi-arid environments. Among the 250 colonies tested, only 33 produced extracellular polygalacturonases: Aureobasidium pullulans (18 isolates), Candida boidinii (one isolate), Trichosporonoides sp. (three isolates), Kluyveromyces marxianus (one isolate), Cryptococcus liquefaciens (one isolate), Pseudozyma sp. (four isolates), and yeast-like related to fungal endophyte (five isolates). The highest activity of polygalacturonase was observed in Pseudozyma sp. CCMB 300 (14.17+/-0.08 micromol acid galacturonic released/min/mg protein). This study shows the potential of yeasts and yeast-like organisms isolated from Brazilian semi-arid environments to produce pectinolytic enzymes. PMID:19462328

Oliveira, Rodrigo Q; Rosa, Carlos A; Uetanabaro, Ana Paula T; Azeredo, Antônio; Neto, Aristóteles Góes; Assis, Sandra A

2009-05-22

450

Respiration in the yeast and mycelial phases of Histoplasma capsulatum.  

PubMed Central

Respiration in the yeast and mycelial phases of Histoplasma capsulatum proceeds via a cytochrome system and an alternate oxidase, both present constitutively. The mycelial cytochrome system is distinguished by an additional partial shunt around the antimycin-sensitive site.

Maresca, B; Lambowitz, A M; Kobayashi, G S; Medoff, G

1979-01-01

451

Baker's yeast assay procedure for testing heavy metal toxicity  

SciTech Connect

Baker's yeast (Saccharomyces cerevisiae) is microorganism which is commercially available and sold as packaged dry pellets in any food store at low cost. Studies have been undertaken on the effects of organic xenobiotics as well as heavy metals on yeast metabolism. This type of study has been generally useful in examining the mechanism(s) of chemical toxicity. However, a rapid and quantitative toxicity test using S. cerevisiae as the test organism has not been developed. The purpose of this study was to develop a toxicity assay for heavy metals, using commercial dry yeast as the test microorganism. This rapid and simple procedure is based on the reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) to INT-formazan by the yeast electron transport system. The scoring of active cells following exposure to heavy metals was undertaken according to the MINT (malachite green-INT) method developed by Bitton and Koopman.

Bitton, G.; Koopman, B.; Wang, H.D.

1984-01-01

452

21 CFR 172.590 - Yeast-malt sprout extract.  

Code of Federal Regulations, 2010 CFR

...conditions: (a) The additive is produced by partial hydrolysis of yeast extract (derived from Saccharomyces cereviseae, Saccharomyces fragilis, or Candida utilis ) using the sprout portion of malt barley as the source of...

2009-04-01

453

Fermentation of Soluble Cello-Oligosaccharides by Yeasts.  

National Technical Information Service (NTIS)

Yeast strains that ferment cellobiose were examined with respect to fermentation on soluble cellodextrin preparations. Hydrolysis of the fermentation products was followed using thin layer chromatography. Candida and Brettanomyces sp. hydrolyze cellobiose...

S. M. Lastick D. D. Spindler K. Grohmann

1983-01-01

454

Biochemical Mutants of Yeast Cells with Impaired Oxidation.  

National Technical Information Service (NTIS)

Under the influence of trypafavine, camphor, and ultroviolet light, yeast cells produce biochemical mutants with impaired oxidation. This impairment of the oxidation apparatus is regularly transmitted to succeeding generations and is retained in the cours...

G. F. Cauze G. V. Kochetkova G. B. Vladimirova

1968-01-01

455

Ethanol and thermotolerance in the bioconversion of xylose by yeasts  

Treesearch

... is critical to maintain proton gradients for metabolic energy and nutrient uptake. ... These factors are particularly detrimental to xylose-fermenting yeasts because ... Likewise, organisms with ATPase activities that resist ethanol inhibition also ...

456

The benefits of humanized yeast models to study Parkinson's disease.  

PubMed

Over the past decade, the baker's yeast Saccharomyces cerevisiae has proven to be a useful model system to investigate fundamental questions concerning the pathogenic role of human proteins in neurodegenerative diseases such as Parkinson's disease (PD). These so-called humanized yeast models for PD initially focused on ? -synuclein, which plays a key role in the etiology of PD. Upon expression of this human protein in the baker's yeast Saccharomyces cerevisiae, the events leading to aggregation and the molecular mechanisms that result in cellular toxicity are faithfully reproduced. More recently, a similar model to study the presumed pathobiology of the ? -synuclein interaction partner synphilin-1 has been established. In this review we will discuss recent advances using these humanized yeast models, pointing to new roles for cell wall integrity signaling, Ca(2+) homeostasis, mitophagy, and the cytoskeleton. PMID:23936613

Franssens, V; Bynens, T; Van den Brande, J; Vandermeeren, K; Verduyckt, M; Winderickx, J

2013-07-01

457

Production of a yeast artificial chromosome for stable expression of a synthetic xylose isomerase-xylulokinase polyprotein in a fuel ethanol yeast strain  

Technology Transfer Automated Retrieval System (TEKTRAN)

Commercialization of fuel ethanol production from lignocellulosic biomass has focused on engineering the glucose-fermenting industrial yeast Saccharomyces cerevisiae to utilize pentose sugars. A yeast artificial chromosome (YAC) was engineered to contain a polyprotein gene construct expressing xylos...

458

Conversion of yeast by hydrothermal treatment under reducing conditions  

Microsoft Academic Search

In the work reported here, baker’s yeast (Saccharomyces cerevisiae) was used as feed for the production of liquid biofuels in a continuous one-step process under hydrothermal conditions in the presence of excess hydrogen and K2CO3. The yeast conversion experiments were performed in an up-flow reactor under near-critical water conditions (T 330–450°C, p 20–32MPa). The products consisted of three phases, an

Alexander Hammerschmidt; Nikolaos Boukis; Ulrich Galla; Eckhard Dinjus; Bernd Hitzmann

2011-01-01

459

Metabolic footprinting as a tool for discriminating between brewing yeasts  

Microsoft Academic Search

The characterization of industrial yeast strains by examining their metabolic foot- prints (exometabolomes) was investigated and compared to genome-based discrimi- natory methods. A group of nine industrial brewing yeasts was studied by comparing their metabolic footprints, genetic fingerprints and comparative genomic hybridiza- tion profiles. Metabolic footprinting was carried out by both direct injection mass spectrometry (DIMS) and gas chromatography time-of-flight

Georgina A. Pope; Donald A. MacKenzie; Marianne Defernez; Miguel A. M. M. Aroso; Linda J. Fuller; Fred A. Mellon; Warwick B. Dunn; Marie Brown; Royston Goodacre; Douglas B. Kell; Marcus E. Marvin; Edward J Louis; Ian N. Roberts

2007-01-01

460

Oral yeast carriage correlates with presence of oral epithelial dysplasia.  

PubMed

Previous studies have suggested a link between the presence of Candida albicans and the development of oral squamous cell carcinoma (OSCC). The aim of the present study was to assess the presence and level of colonisation of oral yeast in patients undergoing an incisional oral mucosal biopsy in order to assess whether the amount of oral yeast present correlated with the presence and degree of oral epithelial dysplastic or neoplastic change. Two hundred and twenty-three patients who were undergoing an incisional biopsy for the diagnosis of an oral mucosal lesion were enrolled in this study. Mouth swills were obtained from each patient for the presence and amount of oral yeast present. Some of the patients (44.6%) had a histopathological diagnosis of either oral epithelial dysplasia (OED) or OSCC and the frequency of oral yeast carriage was significantly greater (P<0.001) in these patients than those without histopathologically detected dysplastic or neoplastic oral lesions. Furthermore, significantly (P<0.001) more patients with OED or OSCC had a higher number of yeast (over 1000 cfu/ml) in their oral cavity than patients without any evidence of epithelial dysplasia or neoplasia histopathologically. The degree of epithelial dysplasia present in these patients also correlated with higher amounts of yeast in the oral cavity (P=0.017). The results of the present study reveal that there is an interaction between oral carriage of yeast and oral epithelial dysplasia, however it remains unclear how yeast infection influences the development and progression of dysplasia. PMID:12076705

McCullough, M; Jaber, M; Barrett, A W; Bain, L; Speight, P M; Porter, S R

2002-06-01

461

Occurrence of Yeasts in Cloacae of Migratory Birds  

Microsoft Academic Search

Several species of yeast have been reported as pathogens in humans based on increases in immunodeficiency syndromes and as\\u000a a result of immunosuppressant chemotherapy in cancer treatment. Domestic and wild birds are known to act as carriers of human\\u000a pathogenic fungi. To gain additional information on the yeasts present in the cloacae of some species of migratory birds,\\u000a 421 wild

C. Cafarchia; A. Camarda; D. Romito; M. Campolo; N. C. Quaglia; D. Tullio; D. Otranto

2006-01-01

462

Dynamics of Nuclear Pore Distribution in Nucleoporin Mutant Yeast Cells  

Microsoft Academic Search

To follow the dynamics of nuclear pore dis- tribution in living yeast cells, we have generated fusion proteins between the green fluorescent protein (GFP) and the yeast nucleoporins Nup49p and Nup133p. In nup133 2 dividing cells that display a constitutive nu- clear pore clustering, in vivo analysis of GFP-Nup49p localization revealed changes in the distribution of nu- clear pore complex

Naïma Belgareh; Valérie Doye

1997-01-01

463

Modelling of Yeast in Suspension During Malt Fermentation Assays  

Microsoft Academic Search

J. Inst. Brew. 115(4), 296-299, 2009 Premature yeast flocculation (PYF) is a poorly understood con- dition leading to attenuation of fermentation and poor alcohol yields. The yeast in suspension in fermenting worts prepared from either normal or premature flocculating malts was continu- ally measured during the small 15 mL fermentation test recently developed in the Dalhousie laboratories. A simple inexpensive

Joseph C. Lake; R. Alex Speers; Tom A. Gill; Anna-Jean M. Reid; Douglas S. Singer

2009-01-01

464

Bioavailability of enterai yeast—selenium in preterm infants  

Microsoft Academic Search

There is no data or literature on the effects of supplementing infants with yeast selenium, although its intestinal absorption\\u000a and bioavailability are higher in adults compared with other selenium compounds.\\u000a \\u000a The aim of the present investigation was to study the impact of selenium enriched yeast on the serum selenium concentration\\u000a of preterm infants living in a low selenium area (Hungary).

Gábor Bogye; Georg Alftham; Tamás Machay

1998-01-01

465

Occurrence and diversity of marine yeasts in Antarctica environments  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

466

A novel oxylipin-associated ‘ghosting’ phenomenon in yeast flocculation  

Microsoft Academic Search

Research on the distribution of oxylipins (3-hydroxy fatty acids) in flocculant strains of the yeast Saccharomyces cerevisiae led to the uncovering of a novel ‘ghosting’ phenomenon observed during assumed lectin-mediated aggregation. We found that intracellular oxylipin-containing osmiophilic layers migrate through yeast cell walls in a ‘ghostlike’ fashion without visually affecting the cell wall structure or the layers. This migration resulted

J. L. F. Kock; P. Venter; D. P. Smith; P. W. J. Van Wyk; P. J. Botes; D. J. Coetzee; C. H. Pohl; A. Botha; K. H. Riedel; S. Nigam

2000-01-01

467

Efficacy of chromium-yeast supplementation for growing beef steers  

Microsoft Academic Search

This experiment was conducted to determine the efficacy of feeding chromium yeast to growing beef steers. Animal growth, gain efficiency, and blood glucose kinetics were determined in 24 beef steers (initial body weight=253 ±4kg) fed a corn silage-based diet supplemented with 0 (control), 100, 200, or 400?g chromium from high-chromium yeast\\/kg of diet dry matter. Intravenous glucose tolerance tests (IVGTT)

K. C Swanson; D. L Harmon; K. A Jacques; B. T Larson; C. J Richards; D. W Bohnert; S. J Paton

2000-01-01

468

Baker’s yeast: challenges and future prospects  

Microsoft Academic Search

In the past few years, recombinant DNA technology has led to the apparition of new baker’s yeast strains, which have optimized\\u000a or novel properties, and in the near future, it is expected that this tool will produce a huge spectrum of specialized yeasts\\u000a of high added value. Their introduction in the manufacturing market will produce a dramatic change in formulation,

Francisca Randez-Gil; Jaime Aguilera; Antonio Codón; Ana Rincón; Francisco Estruch; Jose Prieto

469

Sterol Esterification in Yeast: A Two-Gene Process  

Microsoft Academic Search

Unesterified sterol modulates the function of eukaryotic membranes. In human cells, sterol is esterified to a storage form by acyl-coenzyme A (CoA): cholesterol acyl transferase (ACAT). Here, two genes are identified, ARE1 and ARE2, that encode ACAT-related enzymes in yeast. The yeast enzymes are 49 percent identical to each other and exhibit 23 percent identity to human ACAT. Deletion of

Hongyuan Yang; Martin Bard; Debora A. Bruner; Anne Gleeson; Richard J. Deckelbaum; Gordana Aljinovic; Thomas M. Pohl; Rodney Rothstein; Stephen L. Sturley

1996-01-01

470

Direct transfer of whole genomes from bacteria to yeast.  

PubMed

Transfer of genomes into yeast facilitates genome engineering for genetically intractable organisms, but this process has been hampered by the need for cumbersome isolation of intact genomes before transfer. Here we demonstrate direct cell-to-cell transfer of bacterial genomes as large as 1.8 megabases (Mb) into yeast under conditions that promote cell fusion. Moreover, we discovered that removal of restriction endonucleases from donor bacteria resulted in the enhancement of genome transfer. PMID:23542886

Karas, Bogumil J; Jablanovic, Jelena; Sun, Lijie; Ma, Li; Goldgof, Gregory M; Stam, Jason; Ramon, Adi; Manary, Micah J; Winzeler, Elizabeth A; Venter, J Craig; Weyman, Philip D; Gibson, Daniel G; Glass, John I; Hutchison, Clyde A; Smith, Hamilton O; Suzuki, Yo

2013-03-31

471

Factors affecting the ethanol productivity of yeast in molasses  

Microsoft Academic Search

The ethanol production by a laboratory yeast strain, X2180-1B, was less than half that by an alcohol yeast, YOY655, in a molasses medium containing 30% sugars, although X2180-1B produced approximately the same amount of ethanol as YOY655 in a nutrition medium with the same sugar content. The weak productivity of X2180-1B in the molasses was ascribed to the limitation of

Kazuhiko Takeshige; Kozo Ouchi

1995-01-01

472

Dried yeast ( Saccharomyces cerevisae) as a protein source for horses  

Microsoft Academic Search

The objective of this study was to evaluate the use of dried yeast in the diet of foals when replacing soybean meal to provide 0, 0.25, 0.50, 0.75 and 1.00 of the main protein source. Two trials were performed. Trial one was done to evaluate the influence of yeast on the digestibility of the five diets. Ten foals were kept

B. Winkler; H. Tosi; A. J. F. Webster; F. D. Resende; A. A. M. A. Oliveira; L. C. V. Villela

2011-01-01

473

Diversity of Soil Yeasts Isolated from South Victoria Land, Antarctica  

Microsoft Academic Search

Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in\\u000a Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken\\u000a from sites spanning a diversity of soil habitats that were not directly associated with vertebrate activity. A large proportion\\u000a of yeasts isolated in

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

2008-01-01

474

Biomass and carotenoid pigment production by patagonian native yeasts  

Microsoft Academic Search

Summary  New yeast isolates from unexplored Patagonian habitats were studied for the production of biomass and carotenoids as the first\\u000a step towards the selection of hyper-producing strains and the design of a process optimization approach. Patagonian yeast\\u000a isolates considered as potential biomass and carotenoid sources were studied using ammonium sulphate and urea as nitrogen\\u000a sources in semi-synthetic medium (MMS), and agro-industrial

Diego Libkind; María van Broock

2006-01-01

475

Screening yeasts for the stereoselective reduction of oxoester clofibrate analogues  

Microsoft Academic Search

Reduction of oxoesters 1b–d and 1f,g in the presence of different yeast strains (Saccharomyces cerevisiae DSM 11285, S. cerevisiae CBS 7336, Cryptococcus curvatus ATCC 20509, Candida bombicola ATCC 22214, Trigonopsis variabilis DSM 70714, Kluyveromyces marxianus CBS 6556) affords hydroxy esters 2b–d and 2f,g with diastereoisomeric excesses (de) up to >99%. Hydrolytic enzyme(s) contained in the yeasts catalyzed to some extent

Maria Grazia Perrone; Ernesto Santandrea; Antonio Scilimati; Christoph Syldatk; Vincenzo Tortorella

2005-01-01

476

Effect of xylitol and trehalose on dry resistance of yeasts  

Microsoft Academic Search

The effects of dehydration\\/rehydration on two strains of Saccharomyces cerevisiae: S600, a metabolically engineered xylose-utilising strain, and H158, the non-xylose-utilising host strain; and on the naturally\\u000a xylose-utilising yeast Pachysolen tannophilus CBS 4044, were compared after glucose and xylose utilisation respectively. The yeast strains differed in their ability to\\u000a excrete and accumulate intracellular xylitol. A high intracellular xylitol content before and

I. Krallish; H. Jeppsson; A. Rapoport; B. Hahn-Hägerdal

1997-01-01

477

Catalytic Properties of Phosphopyruvate Carboxylase from Bakers' Yeast  

Microsoft Academic Search

PHOSPHOPYRUVATE (P-EP) carboxylase (systematic name: ATP: oxalacetate carboxy-lyase) (transphosphorylating) is the enzyme responsible for carbon dioxide fixation and oxalacetic acid (OA) synthesis in bakers' yeast1. The enzyme can be extracted soluble from acetone-dried yeast and purified with the procedure summarized in Table 1. P-EP carboxylation was measured at 30° with a spectro-photometrie method. The reaction mixture was made of 0.7

J. J. B. Cannata; A. O. M. Stoppani

1963-01-01

478

Coadaptation of Drosophila and yeasts in their natural habitat  

Microsoft Academic Search

The mutualistic interactions of cactophilicDrosophila and their associated yeasts in the Sonoran Desert are studied as a system which has evolved within the framework of their host cactus stem chemistry. Because theDrosophila-yeast system is saphrophytic, their responses are not thought to directly influence the evolution of the host. Host cactus stem chemistry appears to play an important role in determining

William T. Starmer; James C. Fogleman

1986-01-01

479

Relation between phylogeny and physiology in some ascomycetous yeasts  

Microsoft Academic Search

The question of whether yeasts with similar physiological properties are closely related has been examined using recently\\u000a published phylogenetic analyses of 26S domain D1\\/D2 rDNA nucleotide sequences from all currently recognized ascomycetous yeasts.\\u000a When apparently unique metabolic pathways are examined, some relationships between physiology and rDNA phylogeny are evident.\\u000a Most Candida and Pichia species that are able to assimilate methanol

Wouter J. Middelhoven; Cletus P. Kurtzman

2003-01-01

480

Yeast viral killer toxins: lethality and self-protection  

Microsoft Academic Search

Since the discovery of toxin-secreting killer yeasts more than 40 years ago, research into this phenomenon has provided insights into eukaryotic cell biology and virus–host-cell interactions. This review focuses on the most recent advances in our understanding of the basic biology of virus-carrying killer yeasts, in particular the toxin-encoding killer viruses, and the intracellular processing, maturation and toxicity of the

Frank Breinig; Manfred J. Schmitt

2006-01-01

481

Mitochondrial DNA size diversity in the Dekkera\\/Brettanomyces yeasts  

Microsoft Academic Search

Restriction endonuclease digestion of mitocondrial DNAs from the nine Dekkera\\/Brettanomyces yeasts have revealed that three separate pairs of species, namely D. bruxellensis\\/B. lambicus; B. abstinens\\/B. custersii and B. anomalus\\/B. clausenii have identical genomes. This observation suggests that such analysis of mtDNA could be an important procedure for yeast taxonomy. Sizes of mtDNAs showed a graded range from the 28 kbp

C. R. McArthur; G. D. Clark-Walker

1983-01-01

482

Yeast as a model for ageing and apoptosis research  

Microsoft Academic Search

\\u000a Apoptosis is a form of programmed cell death with a crucial role in health and disease in metazoans. Recent findings demonstrate\\u000a the existence of an apoptotic program also in unicellular eukaryotes. Oxygen stress as well as the expression of several conserved\\u000a proapoptotic genes induce the apoptotic pathway in mammalian cells and yeast cells. The dying yeast cells show diagnostic\\u000a markers

Michael Breitenbach; Frank Madeo; Peter Laun; Gino Heeren; Stefanie Jarolim; Kai-Uwe Fröhlich; Silke Wissing; Alena Pichova

483

Microtubule organization by the budding yeast spindle pole body  

Microsoft Academic Search

In budding yeast microtubule organizing functions are provided by the spindle pole body (SPB), a multi-layered structure that is embedded in the nuclear envelope throughout the cell cycle. The SPB organizes the nuclear and cytoplasmic microtubules which are spatially and functionally distinct. Microtubule formation in yeast requires the Tub4p-complex, containing the ?-tubulin Tub4p, and two additional proteins, the SPB components

Michael Knop; Gislene Pereira; Elmar Schiebel

1999-01-01

484

Phosphorylation of ?-Tubulin Regulates Microtubule Organization in Budding Yeast  

Microsoft Academic Search

?-Tubulin is essential for microtubule nucleation in yeast and other organisms; whether this protein is regulated in vivo has not been explored. We show that the budding yeast ?-tubulin (Tub4p) is phosphorylated in vivo. Hyperphosphorylated Tub4p isoforms are restricted to G1. A conserved tyrosine near the carboxy terminus (Tyr445) is required for phosphorylation in vivo. A point mutation, Tyr445 to

Jacalyn Vogel; Ben Drapkin; Jamina Oomen; Dale Beach; Kerry Bloom; Michael Snyder

2001-01-01

485

Reduction of volatile acidity of wines by selected yeast strains  

Microsoft Academic Search

Herein, we isolate and characterize wine yeasts with the ability to reduce volatile acidity of wines using a refermentation\\u000a process, which consists in mixing the acidic wine with freshly crushed grapes or musts or, alternatively, in the incubation\\u000a with the residual marc. From a set of 135 yeast isolates, four strains revealed the ability to use glucose and acetic acid

A. Vilela-Moura; D. Schuller; A. Mendes-Faia; M. Côrte-Real

2008-01-01

486

Yeasts from glacial ice of Patagonian Andes, Argentina.  

PubMed

Glacial ice and snow are known habitats for cold-adapted microorganisms. Research on cold-adapted yeast biodiversity from Perito Moreno and Mount Tronador glaciers (Patagonia, Argentina), and production of extracellular enzymatic activity at low temperatures (5 and 18 °C), was performed and described in this study. Ninety percent (90%) of the isolates were basidiomycetous; 16 genera and 29 species were identified. Twenty-five percent (25%) of total isolates corresponded to psychrophilic yeasts, whereas 75% were psychrotolerant yeasts. Eighty-five percent (85%) of all isolates had at least one enzymatic activity. Multiple correspondence analysis and cluster classification revealed a relationship between certain genera and some enzymatic activities. Cold-adapted yeast isolates were able to hydrolyze natural compounds (casein, lipids, starch, pectin, and carboxymethylcellulose) at low temperatures, suggesting a significant ecological role of these organisms as organic matter decomposers and nutrient cyclers. These yeasts are especially relevant for metabolic and ecological studies, as well as for yeast-based biotechnological process at low temperatures. PMID:22882330

de Garcia, Virginia; Brizzio, Silvia; van Broock, María Rosa

2012-08-28

487

Plant farnesyltransferase can restore yeast Ras signaling and mating  

SciTech Connect

Farnesyltransferase (FTase) is a heterodimeric enzyme that modifies a group of proteins, including Ras, in mammals and yeasts. Plant FTase {alpha} and {beta} subunits were cloned from tomato and expressed in the yeast Saccharomyces cerevisiae to assess their functional conservation in farnesylating Ras and a-factor proteins, which are important for cell growth and mating. The tomato FTase {beta} subunit (LeFTB) alone was unable to complement the growth defect of ram1{del} mutant yeast strains in which the chromosomal FTase {beta} subunit gene was deleted, but coexpression of LeFTB with the plant {alpha} subunit gene (LeFTA) restored normal growth, Ras membrane association, and mating. LeFTB contains a novel 66-amino-acid sequence domain whose deletion reduces the efficiency of tomato FTase to restore normal growth to yeast ram1{del} strains. Coexpression of LeFTA and LeFTB in either yeast or insect cells yielded a functional enzyme that correctly farnesylated CaaX-motif-containing peptides. Despite their low degree of sequence homology, yeast and plant FTases shared similar in vivo and in vitro substrate specificities, demonstrating that this enzymatic modification of proteins with intermediates from the isoprenoid biosynthesis pathway is conserved in evolutionarily divergent eukaryotes. 56 refs., 7 figs., 1 tab.

Yalovsky, S.; Callan, K.L.; Narita, J.O. [Univ. of California, Berkeley, CA (United States)] [and others

1997-04-01

488

Expression of hepatitis B virus surface antigen in yeast.  

PubMed Central

The structural gene of Hepatitis B virus surface protein (HBsAg) was introduced into a plasmid capable of autonomous replication and selection in both the yeast Saccharomyces cerevisiae and E. coli. In this plasmid transcription of the HBsAg is initiated by the 5'-flanking sequence of the yeast 3-phosphoglycerate kinase (PGK) gene and terminated by the 3'-flanking region of the yeast TRP1 gene. Yeast cells containing this plasmid produce a new major species of mRNA of 1200 nucleotides in length coding for HBsAg. Viral surface antigen is made in nonglycosylated form at a level of about 1-2 percent of total yeast protein. A small fraction of this polypeptide (2-5 percent) is found in aggregated form upon yeast cell disruption by glass beads. This material is similar in size, density, and shape to the 22nm particle, isolated from the plasma of human hepatitis carriers, and induced comparable levels of HBsAg antibodies in mice when compared with the natural particle. Images

Hitzeman, R A; Chen, C Y; Hagie, F E; Patzer, E J; Liu, C C; Estell, D A; Miller, J V; Yaffe, A; Kleid, D G; Levinson, A D; Oppermann, H

1983-01-01

489

Ethanol production from cellulosic materials using cellulase-expressing yeast.  

PubMed

We demonstrate direct ethanol fermentation from amorpho