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Sample records for coli ko11 saccharomyces

  1. Ethanol production from marine algal hydrolysates using Escherichia coli KO11.

    Science.gov (United States)

    Kim, Nag-Jong; Li, Hui; Jung, Kwonsu; Chang, Ho Nam; Lee, Pyung Cheon

    2011-08-01

    Algae biomass is a potential raw material for the production of biofuels and other chemicals. In this study, biomass of the marine algae, Ulva lactuca, Gelidium amansii,Laminaria japonica, and Sargassum fulvellum, was treated with acid and commercially available hydrolytic enzymes. The hydrolysates contained glucose, mannose, galactose, and mannitol, among other sugars, at different ratios. The Laminaria japonica hydrolysate contained up to 30.5% mannitol and 6.98% glucose in the hydrolysate solids. Ethanogenic recombinant Escherichia coli KO11 was able to utilize both mannitol and glucose and produced 0.4g ethanol per g of carbohydrate when cultured in L. japonica hydrolysate supplemented with Luria-Bertani medium and hydrolytic enzymes. The strategy of acid hydrolysis followed by simultaneous enzyme treatment and inoculation with E. coli KO11 could be a viable strategy to produce ethanol from marine alga biomass. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Fermentation of sweet whey by recombinant Escherichia coli K011 Fermentação de soro de leite por Escherichia coli KO11 recombinante

    Directory of Open Access Journals (Sweden)

    Amarildo Ricardo Leite

    2000-09-01

    Full Text Available The production of ethanol from sweet whey using the recombinant Escherichia coli KO11, in batch fermentation, was tested. The maximum ethanol yield was reached after 96h, representing only 38% of the theoretical yield. The supplementation of whey with components of LB broth increased the maximum yield to 96% in 72h. The addition of 0.5% yeast extract to whey resulted in maximum yield of 74% at 36h and it increased to over 100% when yeast extract and trace metals solution (Fe++, Mn++ and Zn++ were added.A produção de etanol a partir de soro de leite empregando a cepa Escherichia coli KO11 recombinante, em fermentação de batelada, foi testada. O rendimento máximo de etanol foi obtido em 96h, representando apenas 38% do rendimento teórico. A suplementação do soro com os componentes do caldo LB aumentou o rendimento para 96% em 72h. A adição de 0,5% de extrato de levedura ao soro resultou em um rendimento máximo de 74% em 36h que aumentou para acima de 100% quando se adicionou extrato de levedura e uma solução de metais traço (Fe++, Mn++ e Zn++.

  3. Comparative study of Bifidobacterium animalis, Escherichia coli, Lactobacillus casei and Saccharomyces boulardii probiotic properties.

    Science.gov (United States)

    Martins, Flaviano S; Silva, Aparecida A; Vieira, Angélica T; Barbosa, Flávio H F; Arantes, Rosa M E; Teixeira, Mauro M; Nicoli, Jacques Robert

    2009-08-01

    The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.

  4. Production and Purification of the Native Saccharomyces cerevisiae Hsp12 in Escherichia coli.

    Science.gov (United States)

    Léger, Antoine; Hocquellet, Agnès; Dieryck, Wilfrid; Moine, Virginie; Marchal, Axel; Marullo, Philippe; Josseaume, Annabelle; Cabanne, Charlotte

    2017-09-20

    Hsp12 is a small heat shock protein produced in many organisms, including the yeast Saccharomyces cerevisiae. It has been described as an indicator of yeast stress rate and has also been linked to the sweetness sensation of wine. To obtain a sufficient amount of protein, we produced and purified Hsp12 without tag in Escherichia coli. A simple fast two-step process was developed using a microplate approach and a design of experiments. A capture step on an anion-exchange salt-tolerant resin was followed by size exclusion chromatography for polishing, leading to a purity of 97%. Thereafter, specific anti-Hsp12 antibodies were obtained by rabbit immunization. An ELISA was developed to quantify Hsp12 in various strains of Saccharomyces cerevisiae. The antibodies showed high specificity and allowed the quantitation of Hsp12 in the yeast. The quantities of Hsp12 measured in the strains differed in direct proportion to the level of expression found in previous studies.

  5. Hurdle technology applied to prickly pear beverages for inhibiting Saccharomyces cerevisiae and Escherichia coli.

    Science.gov (United States)

    García-García, R; Escobedo-Avellaneda, Z; Tejada-Ortigoza, V; Martín-Belloso, O; Valdez-Fragoso, A; Welti-Chanes, J

    2015-06-01

    The effect of pH reduction (from 6·30-6·45 to 4·22-4·46) and the addition of antimicrobial compounds (sodium benzoate and potassium sorbate) on the inhibition of Saccharomyces cerevisiae and Escherichia coli in prickly pear beverages formulated with the pulp and peel of Villanueva (V, Opuntia albicarpa) and Rojo Vigor (RV, Opuntia ficus-indica) varieties during 14 days of storage at 25°C, was evaluated. RV variety presented the highest microbial inhibition. By combining pH reduction and preservatives, reductions of 6·2-log10 and 2·3-log10 for E. coli and S. cerevisiae were achieved respectively. Due to the low reduction of S. cerevisiae, pulsed electric fields (PEF) (11-15 μs/25-50 Hz/27-36 kV cm(-1)) was applied as another preservation factor. The combination of preservatives, pH reduction and PEF at 13-15 μs/25-50 Hz for V variety, and 11 μs/50 Hz, 13-15 μs/25-50 Hz for RV, had a synergistic effect on S. cerevisiae inhibition, achieving at least 3·4-log10 of microbial reduction immediately after processing, and more than 5-log10 at fourth day of storage at 25°C maintained this reduction during 21 days of storage (P > 0·05). Hurdle technology using PEF in combination with other factors is adequate to maintain stable prickly pear beverages during 21 days/25°C. Significance and impact of the study: Prickly pear is a fruit with functional value, with high content of nutraceuticals and antioxidant activity. Functional beverages formulated with the pulp and peel of this fruit represent an alternative for its consumption. Escherichia coli and Saccharomyces cerevisiae are micro-organisms that typically affect fruit beverage quality and safety. The food industry is looking for processing technologies that maintain quality without compromising safety. Hurdle technology, including pulsed electric fields (PEF) could be an option to achieve this. The combination of PEF, pH reduction and preservatives is an alternative to obtain safe and minimally processed

  6. How Escherichia coli and Saccharomyces cerevisiae build Fe/S proteins.

    Science.gov (United States)

    Barras, Frédéric; Loiseau, Laurent; Py, Béatrice

    2005-01-01

    , plants and parasites. ISC and SUF systems share a common core function made of a cysteine desulfurase, which acts as a sulfur donor, and scaffold proteins, which act as sulfur and iron acceptors. The ISC and SUF systems also exhibit important differences. In particular, the ISC system includes an Hsp70/Hsp40-like pair of chaperones, while the SUF system involves an unorthodox ATP-binding cassette (ABC)-like component. The role of these two sets of ATP-hydrolyzing proteins in Fe/S cluster biogenesis remains unclear. Both systems are likely to target overlapping sets of apoproteins. However, regulation and phenotypic studies in E. coli, which synthesizes both types of systems, leads us to envisage ISC as the house-keeping one that functions under normal laboratory conditions, while the SUF system appears to be required in harsh environmental conditions such as oxidative stress and iron starvation. In Saccharomyces cerevisiae, the ISC system is located in the mitochondria and its function is necessary for maturation of both mitochondrial and cytosolic Fe/S proteins. Here, we attempt to provide the first comprehensive review of the ISC and SUF systems since their discovery in the mid and late 1990s. Most emphasis is put on E. coli and S. cerevisiae models with reference to other organisms when their analysis provided us with information of particular significance. We aim at covering information made available on each Isc and Suf component by the different experimental approaches, including physiology, gene regulation, genetics, enzymology, biophysics and structural biology. It is our hope that this parallel coverage will facilitate the identification of both similarities and specificities of ISC and SUF systems.

  7. Efficient Production of γ-GABA Using Recombinant E. coli Expressing Glutamate Decarboxylase (GAD) Derived from Eukaryote Saccharomyces cerevisiae.

    Science.gov (United States)

    Xiong, Qiang; Xu, Zheng; Xu, Lu; Yao, Zhong; Li, Sha; Xu, Hong

    2017-12-01

    γ-Aminobutyric acid (γ-GABA) is a non-proteinogenic amino acid, which acts as a major regulator in the central nervous system. Glutamate decarboxylase (namely GAD, EC 4.1.1.15) is known to be an ideal enzyme for γ-GABA production using L-glutamic acid as substrate. In this study, we cloned and expressed GAD gene from eukaryote Saccharomyces cerevisiae (ScGAD) in E. coli BL21(DE3). This enzyme was further purified and its optimal reaction temperature and pH were 37 °C and pH 4.2, respectively. The cofactor of ScGAD was verified to be either pyridoxal 5'-phosphate (PLP) or pyridoxal hydrochloride. The optimal concentration of either cofactor was 50 mg/L. The optimal medium for E. coli-ScGAD cultivation and expression were 10 g/L lactose, 5 g/L glycerol, 20 g/L yeast extract, and 10 g/L sodium chloride, resulting in an activity of 55 U/mL medium, three times higher than that of using Luria-Bertani (LB) medium. The maximal concentration of γ-GABA was 245 g/L whereas L-glutamic acid was near completely converted. These findings provided us a good example for bio-production of γ-GABA using recombinant E. coli expressing a GAD enzyme derived from eukaryote.

  8. A plug-and-play pathway refactoring workflow for natural product research in Escherichia coli and Saccharomyces cerevisiae.

    Science.gov (United States)

    Ren, Hengqian; Hu, Pingfan; Zhao, Huimin

    2017-08-01

    Pathway refactoring serves as an invaluable synthetic biology tool for natural product discovery, characterization, and engineering. However, the complicated and laborious molecular biology techniques largely hinder its application in natural product research, especially in a high-throughput manner. Here we report a plug-and-play pathway refactoring workflow for high-throughput, flexible pathway construction, and expression in both Escherichia coli and Saccharomyces cerevisiae. Biosynthetic genes were firstly cloned into pre-assembled helper plasmids with promoters and terminators, resulting in a series of expression cassettes. These expression cassettes were further assembled using Golden Gate reaction to generate fully refactored pathways. The inclusion of spacer plasmids in this system would not only increase the flexibility for refactoring pathways with different number of genes, but also facilitate gene deletion and replacement. As proof of concept, a total of 96 pathways for combinatorial carotenoid biosynthesis were built successfully. This workflow should be generally applicable to different classes of natural products produced by various organisms. Biotechnol. Bioeng. 2017;114: 1847-1854. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  9. Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study

    OpenAIRE

    Lee, Gun Joon; Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun; Lee, Dong-Un

    2015-01-01

    We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 ?s were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The ...

  10. Porting the synthetic D-glucaric acid pathway from Escherichia coli to Saccharomyces cerevisiae.

    Science.gov (United States)

    Gupta, Amita; Hicks, Michael A; Manchester, Shawn P; Prather, Kristala L J

    2016-09-01

    D-Glucaric acid can be produced as a value-added chemical from biomass through a de novo pathway in Escherichia coli. However, previous studies have identified pH-mediated toxicity at product concentrations of 5 g/L and have also found the eukaryotic myo-inositol oxygenase (MIOX) enzyme to be rate-limiting. We ported this pathway to Saccaromyces cerevisiae, which is naturally acid-tolerant and evaluate a codon-optimized MIOX homologue. We constructed two engineered yeast strains that were distinguished solely by their MIOX gene - either the previous version from Mus musculus or a homologue from Arabidopsis thaliana codon-optimized for expression in S. cerevisiae - in order to identify the rate-limiting steps for D-glucaric acid production both from a fermentative and non-fermentative carbon source. myo-Inositol availability was found to be rate-limiting from glucose in both strains and demonstrated to be dependent on growth rate, whereas the previously used M. musculus MIOX activity was found to be rate-limiting from glycerol. Maximum titers were 0.56 g/L from glucose in batch mode, 0.98 g/L from glucose in fed-batch mode, and 1.6 g/L from glucose supplemented with myo-inositol. Future work focusing on the MIOX enzyme, the interplay between growth and production modes, and promoting aerobic respiration should further improve this pathway. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Physiology of inactivation of microbial cells by near-ultraviolet light: mode of action and application for the enrichment of mutants of Escherichia coli and saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Peters, J.

    1976-01-01

    The mode of action of near-ultraviolet (NUV) light was studied in Escherichia coli. NUV light (maximum emission at 365 nm) caused the photodestruction of ribonucleoside diphosphate (RDP) reductase activity in vivo. Evidence was presented for a model suggesting that the loss of RDP-reductase resulted in a metabolic state analogous to that produced during starvation for thymine. Some important properties of cells irradiated by NUV light, cell death, loss of the ability to support the replication of DNA phages and a delay in the onset of cell division in sublethally irradiated cells, were accounted for in terms of photoinactivation of RDP-reductase. Conditions were described under which NUV light was an effective counterselective agent for the enrichment of mutants of Escherichia coli and Saccharomyces cerevisiae

  12. Saccharomyces Boulardii

    Science.gov (United States)

    Saccharomyces boulardii is a yeast, which is a type of fungus. Saccharomyces boulardii was previously identified as a unique species of ... be a strain of Saccharomyces cerevisiae (baker's yeast). Saccharomyces boulardii is used as medicine. Saccharomyces boulardii is most ...

  13. Characterization of RAD4 gene required for ultraviolet-induced excision repair of Saccharomyces cerevisiae propagated in Escherichia coli without inactivation

    International Nuclear Information System (INIS)

    Choi, I.S.; Kim, J.B.; Lee, K.N.; Park, S.D.

    1990-01-01

    The previously isolated RAD4 gene designated as pPC1 from the genomic library of Saccharomyces cerevisiae appeared to propagate in Escherichia coli and yet retained its complementing activity of rad4 mutants without inactivation. The subcloned RAD4 gene was found to be localized within a 2.5 kb DNA fragment flanking Bg/II and BamHI sites in the insert DNA, and was shown to have the same restriction map as a yeast chromosomal DNA, as determined by Southern hybridization. Tetrad analysis and pulse-field chromosome mapping have revealed that the cloned RAD4 gene can be mapped and integrated into the yeast chromosome V, the actual site of this gene. DNA-tRNA hybridization has shown that the isolated RAD4 gene did not contain a suppressor tRNA gene. These results have indicated that the pPC1 is a functional RAD4 gene playing a unique role involved in the nucleotide excision repair of yeast without any genetic change during amplification in E. coli. (author)

  14. Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study

    Science.gov (United States)

    Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun

    2015-01-01

    We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 μs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (pelectric-field strength of 10 kV/cm can be used to pasteurize low-fat milk. PMID:26877640

  15. Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study.

    Science.gov (United States)

    Lee, Gun Joon; Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun; Lee, Dong-Un

    2015-01-01

    We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 μs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (ppasteurize low-fat milk.

  16. Oxygen requirement for near-UV mediated cytotoxicity of α-terthienyl to Escherichia coli and Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Arnason, T.; Chan, G.F.Q.; Wat, C.K.; Downum, K.; Towers, G.H.N.

    1981-01-01

    The photosensitizing activity of α-terthienyl, a naturally occurring compound from Tagetes has been studied. Fluence-response curves for the effect of α-terthienyl and near-UV radiation on Escherichia coli have been prepared. Photosensitization of E. coli was enhanced in aerobic as compared to anaerobic conditions and exogenous superoxide dismutase had a slight protective effect. Sodium azide, a quencher of 1 O 2 , protected yeast cells from photosensitization with α-terthienyl. The available evidence suggests that α-terthienyl acts as a photodynamic sensitizer in vivo. (author)

  17. Optimal cofactor swapping can increase the theoretical yield for chemical production in Escherichia coli and Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    King, Zachary A.; Feist, Adam

    2014-01-01

    Maintaining cofactor balance is a critical function in microorganisms, but often the native cofactor balance does not match the needs of an engineered metabolic flux state. Here, an optimization procedure is utilized to identify optimal cofactor-specificity "swaps" for oxidoreductase enzymes...... specificity of central metabolic enzymes (especially GAPD and ALCD2x) is shown to increase NADPH production and increase theoretical yields for native products in E. coli and yeast-including l-aspartate, l-lysine, l-isoleucine, l-proline, l-serine, and putrescine-and non-native products in E. coli-including 1...

  18. Saccharomyces boulardii Preserves the Barrier Function and Modulates the Signal Transduction Pathway Induced in Enteropathogenic Escherichia coli-Infected T84 Cells

    Science.gov (United States)

    Czerucka, Dorota; Dahan, Stephanie; Mograbi, Baharia; Rossi, Bernard; Rampal, Patrick

    2000-01-01

    Use of the nonpathogenic yeast Saccharomyces boulardii in the treatment of infectious diarrhea has attracted growing interest. The present study designed to investigate the effect of this yeast on enteropathogenic Escherichia coli (EPEC)-associated disease demonstrates that S. boulardii abrogated the alterations induced by an EPEC strain on transepithelial resistance, [3H]inulin flux, and ZO-1 distribution in T84 cells. Moreover, EPEC-mediated apoptosis of epithelial cells was delayed in the presence of S. boulardii. The yeast did not modify the number of adherent bacteria but lowered by 50% the number of intracellular bacteria. Infection by EPEC induced tyrosine phosphorylation of several proteins in T84 cells, including p46 and p52 SHC isoforms, that was attenuated in the presence of S. boulardii. Similarly, EPEC-induced activation of the ERK1/2 mitogen-activated protein (MAP) kinase pathway was diminished in the presence of the yeast. Interestingly, inhibition of the ERK1/2 pathway with the specific inhibitor PD 98059 decreased EPEC internalization, suggesting that modulation of the ERK1/2 MAP pathway might account for the lowering of the number of intracellular bacteria observed in the presence of S. boulardii. Altogether, this study demonstrated that S. boulardii exerts a protective effect on epithelial cells after EPEC adhesion by modulating the signaling pathway induced by bacterial infection. PMID:10992512

  19. One-pot green synthesis of carbon dots by using Saccharum officinarum juice for fluorescent imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae) cells

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Vaibhavkumar N. [Applied Chemistry Department, S. V. National Institute of Technology, Surat, 395 007 (India); Jha, Sanjay [Gujarat Agricultural Biotechnology Institute, Navsari Agricultural University, Surat, 395007 (India); Kailasa, Suresh Kumar, E-mail: sureshkumarchem@gmail.com [Applied Chemistry Department, S. V. National Institute of Technology, Surat, 395 007 (India)

    2014-05-01

    We are reporting highly economical plant-based hydrothermal method for one-pot green synthesis of water-dispersible fluorescent carbon dots (CDs) by using Saccharum officinarum juice as precursor. The synthesized CDs were characterized by UV-visible, fluorescence, Fourier transform infrared (FT-IR), dynamic light scattering (DLS), high-resolution transmission electron microscopic (HR-TEM), and laser scanning confocal microscopic techniques. The CDs are well dispersed in water with an average size of ∼ 3 nm and showed bright blue fluorescence under UV-light (λ{sub ex} = 365 nm). These CDs acted as excellent fluorescent probes in cellular imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae). - Highlights: • One-pot green synthesis was used for fluorescent CDs. • FT-IR, DLS, and TEM were used for the characterization of CDs. • The CDs are well dispersed in water with an average size of ∼ 3 nm. • The CDs acted as fluorescent probes for imaging of bacteria and yeast cells.

  20. Effect of Saccharomyces cerevisiae var. Boulardii and β-galactomannan oligosaccharide on porcine intestinal epithelial and dendritic cells challenged in vitro with Escherichia coli F4 (K88

    Directory of Open Access Journals (Sweden)

    Badia Roger

    2012-01-01

    Full Text Available Abstract Probiotic and prebiotics, often called "immune-enhancing" feed additives, are believed to deal with pathogens, preventing the need of an immune response and reducing tissue damage. In this study, we investigated if a recently developed β-galactomannan (βGM had a similar protective role compared to Saccharomyces cerevisiae var. Boulardii (Scb, a proven probiotic, in the context of enterotoxigenic Escherichia coli (ETEC infection. ETEC causes inflammation, diarrhea and intestinal damage in piglets, resulting in large economic loses worldwide. We observed that Scb and βGM products inhibited in vitro adhesion of ETEC on cell surface of porcine intestinal IPI-2I cells. Our data showed that Scb and βGM decreased the mRNA ETEC-induced gene expression of pro-inflammatory cytokines TNF-α, IL-6, GM-CSF and chemokines CCL2, CCL20 and CXCL8 on intestinal IPI-2I. Furthermore, we investigated the putative immunomodulatory role of Scb and βGM on porcine monocyte-derived dendritic cells (DCs per se and under infection conditions. We observed a slight up-regulation of mRNA for TNF-α and CCR7 receptor after co-incubation of DC with Scb and βGM. However, no differences were found in DC activation upon ETEC infection and Scb or βGM co-culture. Therefore, our results indicate that, similar to probiotic Scb, prebiotic βGM may protect intestinal epithelial cells against intestinal pathogens. Finally, although these products may modulate DC activation, their effect under ETEC challenge conditions remains to be elucidated.

  1. Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Bojsen, Rasmus K; Andersen, Kaj Scherz; Regenberg, Birgitte

    2012-01-01

    Microbial biofilms can be defined as multi-cellular aggregates adhering to a surface and embedded in an extracellular matrix (ECM). The nonpathogenic yeast, Saccharomyces cerevisiae, follows the common traits of microbial biofilms with cell-cell and cell-surface adhesion. S. cerevisiae is shown t...

  2. The effect of essential oil of basil (Ocimum basilicum L.) on UV-induced mutagenesis in Escherichia coli and Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Stanojević, Jasna; Berić, Tanja; Opačić, Biljana; Vuković-Gačić, Branka; Simić, Draga; Knežević-Vukčević, Jelena [Institute of Botany, Faculty of Biology, University of Belgrade, 11000 Belgrade (Serbia)

    2008-07-01

    The antimutagenic potential of essential oil (EO) of basil (Ocimum basilicum L.) and its major constituent linalool were studied with the E. coli K12 and S. cerevisiae D7 assays. In the E. coli assay, EO and linalool inhibited UV-induced mutagenesis in a repair-proficient strain, but had no effect on spontaneous mutagenesis in repair-proficient, nucleotide excision repair-deficient, and mismatch-deficient strains. By testing participation of different mechanisms involved in antimutagenesis, it was concluded that the antimutagenic effect against UV-induced mutagenesis involved decrease of protein synthesis and cell proliferation which led to increased efficiency of nucleotide excision repair. An antimutagenic effect of basil derivatives in S. cerevisiae was not detected. (author)

  3. The effect of essential oil of basil (Ocimum basilicum L.) on UV-induced mutagenesis in Escherichia coli and Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stanojević, Jasna; Berić, Tanja; Opačić, Biljana; Vuković-Gačić, Branka; Simić, Draga; Knežević-Vukčević, Jelena

    2008-01-01

    The antimutagenic potential of essential oil (EO) of basil (Ocimum basilicum L.) and its major constituent linalool were studied with the E. coli K12 and S. cerevisiae D7 assays. In the E. coli assay, EO and linalool inhibited UV-induced mutagenesis in a repair-proficient strain, but had no effect on spontaneous mutagenesis in repair-proficient, nucleotide excision repair-deficient, and mismatch-deficient strains. By testing participation of different mechanisms involved in antimutagenesis, it was concluded that the antimutagenic effect against UV-induced mutagenesis involved decrease of protein synthesis and cell proliferation which led to increased efficiency of nucleotide excision repair. An antimutagenic effect of basil derivatives in S. cerevisiae was not detected. (author)

  4. The Saccharomyces cerevisiae RAD30 gene, a homologue of Escherichia coli dinB and umuC, is DNA damage inducible and functions in a novel error-free postreplication repair mechanism

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, J. P. [NIH, Bethesda, MD. (United States); Levine, A. S.; Woodgate, R.

    1997-12-15

    Damage-inducible mutagenesis in prokaryotes is largely dependent upon the activity of the UmuD'C-like proteins. Since many DNA repair processes are structurally and/or functionally conserved between prokaryotes and eukaryotes, we investigated the role of RAD30, a previously uncharacterized Saccharomyces cerevisiae DNA repair gene related to the Escherichia coli dinB, umuC and S. cerevisiae REV1 genes, in UV resistance and UV-induced mutagenesis. Similar to its prokaryotic homologues, RAD30 was found to be damage inducible. Like many S. cerevisiae genes involved in error-prone DNA repair, epistasis analysis clearly places RAD30 in the RAD6 group and rad30 mutants display moderate UV sensitivity reminiscent of rev mutants. However, unlike rev mutants, no defect in UV-induced reversion was seen in rad30 strains. While rad6 and rad18 are both epistatic to rad30, no epistasis was observed with rev1, rev3, rev7 or rad5, all of which are members of the RAD6 epistasis group. These findings suggest that RD30 participates in a novel error-free repair pathway dependent on RAD6 and RAD18, but independent of REV1, REV3, REV7 and RAD5. (author)

  5. Excision repair and mutagenesis in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Kilbey, Brian

    1987-01-01

    This and succeeding letters discuss the James and Kilbey (1977 and 1978) model for the initiation of u.v. mutagenesis in Saccharomyces cerevisiae and its application to include a number of chemical mutagens. The Baranowska et al (1987) results indicating the role of DNA replication, the differing mechanisms in Escherichia coli, are all discussed. (UK)

  6. Heterooligomeric phosphoribosyl diphosphate synthase of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne

    2004-01-01

    The yeast Saccharomyces cerevisiae contains five phosphoribosyl diphosphate (PRPP) synthase-homologous genes (PRS1-5), which specify PRPP synthase subunits 1-5. Expression of the five S. cerevisiae PRS genes individually in an Escherichia coli PRPP-less strain (Deltaprs) showed that a single PRS...

  7. Reconstruction of the biosynthetic pathway for the core fungal polyketide scaffold rubrofusarin in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Rugbjerg, Peter; Naesby, Michael; Mortensen, Uffe Hasbro

    2013-01-01

    production in easily fermentable and genetically engineerable organisms, such as Saccharomyces cerevisiae and Escherichia coli are desirable. Rubrofusarin is an orange polyketide pigment that is a common intermediate in many different fungal biosynthetic pathways. RESULTS: In this study, we established...

  8. Molecular genetic diversity of the Saccharomyces yeasts in Taiwan: Saccharomyces arboricola, Saccharomyces cerevisiae and Saccharomyces kudriavzevii.

    Science.gov (United States)

    Naumov, Gennadi I; Lee, Ching-Fu; Naumova, Elena S

    2013-01-01

    Genetic hybridization, sequence and karyotypic analyses of natural Saccharomyces yeasts isolated in different regions of Taiwan revealed three biological species: Saccharomyces arboricola, Saccharomyces cerevisiae and Saccharomyces kudriavzevii. Intraspecies variability of the D1/D2 and ITS1 rDNA sequences was detected among S. cerevisiae and S. kudriavzevii isolates. According to molecular and genetic analyses, the cosmopolitan species S. cerevisiae and S. kudriavzevii contain local divergent populations in Taiwan, Malaysia and Japan. Six of the seven known Saccharomyces species are documented in East Asia: S. arboricola, S. bayanus, S. cerevisiae, S. kudriavzevii, S. mikatae, and S. paradoxus.

  9. Expression of the E.coli pntA and pntB genes encoding nicotinamide nucleotide transhydrogenase in Saccharomyces cerevisiae and its effect on product formation during anaerobic glucose fermentation

    DEFF Research Database (Denmark)

    Anderlund, M.; Nissen, Torben Lauesgaard; Nielsen, Jens Bredal

    1999-01-01

    was present. Unlike the situation in E. coli, however, most of the transhydrogenase activity was not present in the yeast plasma membrane; rather, the enzyme appeared to remain localized in the membrane of the endoplasmic reticulum. During anaerobic glucose fermentation we observed an increase...

  10. E. Coli

    Science.gov (United States)

    ... for the bacteria's medical name Escherichia coli . The strange thing about these bacteria — and lots of other ... In some cases, E. coli poisoning can cause life-threatening kidney problems. What Can Kids Do? Adults ...

  11. Engineering Escherichia coli for improved ethanol production from gluconate.

    Science.gov (United States)

    Hildebrand, Amanda; Schlacta, Theresa; Warmack, Rebeccah; Kasuga, Takao; Fan, Zhiliang

    2013-10-10

    We report on engineering Escherichia coli to produce ethanol at high yield from gluconic acid (gluconate). Knocking out genes encoding for the competing pathways (l-lactate dehydrogenase and pyruvate formate lyase A) in E. coli KO11 eliminated lactate production, lowered the carbon flow toward acetate production, and improved the ethanol yield from 87.5% to 97.5% of the theoretical maximum, while the growth rate of the mutant strain was about 70% of the wild type. The corresponding genetic modifications led to a small improvement of ethanol yield from 101.5% to 106.0% on glucose. Deletion of the pyruvate dehydrogenase gene (pdh) alone improved the ethanol yield from 87.5% to 90.4% when gluconate was a substrate. The growth rate of the mutant strain was identical to that of the wild type. The corresponding genetic modification led to no improvements on ethanol yield on glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Kinetics of phosphomevalonate kinase from Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    David E Garcia

    Full Text Available The mevalonate-based isoprenoid biosynthetic pathway is responsible for producing cholesterol in humans and is used commercially to produce drugs, chemicals, and fuels. Heterologous expression of this pathway in Escherichia coli has enabled high-level production of the antimalarial drug artemisinin and the proposed biofuel bisabolane. Understanding the kinetics of the enzymes in the biosynthetic pathway is critical to optimize the pathway for high flux. We have characterized the kinetic parameters of phosphomevalonate kinase (PMK, EC 2.7.4.2 from Saccharomyces cerevisiae, a previously unstudied enzyme. An E. coli codon-optimized version of the S. cerevisiae gene was cloned into pET-52b+, then the C-terminal 6X His-tagged protein was expressed in E. coli BL21(DE3 and purified on a Ni²⁺ column. The KM of the ATP binding site was determined to be 98.3 µM at 30°C, the optimal growth temperature for S. cerevisiae, and 74.3 µM at 37°C, the optimal growth temperature for E. coli. The K(M of the mevalonate-5-phosphate binding site was determined to be 885 µM at 30°C and 880 µM at 37°C. The V(max was determined to be 4.51 µmol/min/mg enzyme at 30°C and 5.33 µmol/min/mg enzyme at 37°C. PMK is Mg²⁺ dependent, with maximal activity achieved at concentrations of 10 mM or greater. Maximum activity was observed at pH = 7.2. PMK was not found to be substrate inhibited, nor feedback inhibited by FPP at concentrations up to 10 µM FPP.

  13. In vitro screening of probiotic properties of Saccharomyces cerevisiae var. boulardii and food-borne Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    van der Aa Kuhle, Alis; Skovgaard, Kerstin; Jespersen, Lene

    2005-01-01

    .6-16.8%) recorded for two isolates from blue veined cheeses. Merely 25% of the S. cerevisiae var. boulardii strains displayed good adhesive properties (16.2-28.0%). The expression of the proinflammatory cytokine IL-1α decreased strikingly in IPEC-J2 cells exposed to a Shiga-like toxin 2e producing Escherichia coli...... strain when the cells were pre- and coincubated with S. cerevisiae var. boulardii even though this yeast strain was low adhesive (5.4%), suggesting that adhesion is not a mandatory prerequisite for such a probiotic effect. A strain of S. cerevisiae isolated from West African sorghum beer exerted similar......The probiotic potential of IS Saccharomyces cerevisiae strains used for production of foods or bevel-ages or isolated from such, and eight strains of Saccharomyces cerevisiae var. boulardii, was investigated. All strains included were able to withstand pH 2.5 and 0.3% Ox-all. Adhesion...

  14. Karyotypes of Saccharomyces sensu lato species

    DEFF Research Database (Denmark)

    Petersen, Randi Føns; Nilsson-Tilgren, Torsten; Piskur, Jure

    1999-01-01

    An improved pulsed-field electrophoresis program was developed to study differently sized chromosomes within the genus Saccharomyces. The number of chromosomes in the type strains was shown to be nine in Saccharomyces castellii and Saccharomyces dairenensis, 12 in Saccharomyces servazzii...... and Saccharomyces unisporus, 16 in Saccharomyces exiguus and seven in Saccharomyces kluyveri. The sizes of individual chromosomes were resolved and the approximate genome sizes were determined by the addition of individual chromosomes of the karyotypes. Apparently. the genome of S. exiguus, which is the only...... Saccharomyces sensu late yeast to contain small chromosomes, is larger than that of Saccharomyces cerevisiae. On the other hand, other species exhibited genome sizes that were 10-25% smaller than that of S. cerevisiae. Well-defined karyotypes represent the basis for future genome mapping and sequencing projects...

  15. Fungal genomics beyond Saccharomyces cerevisiae?

    DEFF Research Database (Denmark)

    Hofmann, Gerald; Mcintyre, Mhairi; Nielsen, Jens

    2003-01-01

    Fungi are used extensively in both fundamental research and industrial applications. Saccharomyces cerevisiae has been the model organism for fungal research for many years, particularly in functional genomics. However, considering the diversity within the fungal kingdom, it is obvious...

  16. Effects of fermentation by Saccharomyces cerevisiae and ...

    African Journals Online (AJOL)

    yassine

    2013-02-13

    Feb 13, 2013 ... Effect of Saccharomyces cerevisiae fermentation on the ... beetroot, fermentation, Saccharomyces cerevisiae, betalain compounds. ... by Saccharomyces cerevisiae strains (González et al., .... Both red and yellow pigments were influenced during S. .... in beverages such as white wine, grape fruit, and green.

  17. [Saccharomyces cerevisiae infections].

    Science.gov (United States)

    Souza Goebel, Cristine; de Mattos Oliveira, Flávio; Severo, Luiz Carlos

    2013-01-01

    Saccharomyces cerevisiae is an ubiquitous yeast widely used in industry and it is also a common colonizer of the human mucosae. However, the incidence of invasive infection by these fungi has significantly increased in the last decades. To evaluate the infection by S. cerevisiae in a hospital in southern Brazil during a period of 10 years (2000-2010). Review of medical records of patients infected by this fungus. In this period, 6 patients were found to be infected by S. cerevisiae. The age range of the patients was from 10 years to 84. Urine, blood, ascitic fluid, peritoneal dialysis fluid, and esophageal biopsy samples were analyzed. The predisposing factors were cancer, transplant, surgical procedures, renal failure, use of venous catheters, mechanical ventilation, hospitalization in Intensive Care Unit, diabetes mellitus, chemotherapy, corticosteroid use, and parenteral nutrition. Amphotericin B and fluconazole were the treatments of choice. Three of the patients died and the other 3 were discharged from hospital. We must take special precautions in emerging infections, especially when there are predisposing conditions such as immunosuppression or patients with serious illnesses. The rapid and specific diagnosis of S. cerevisiae infections is important for therapeutic decision. Furthermore, epidemiological and efficacy studies of antifungal agents are necessary for a better therapeutic approach. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  18. Escherichia Coli

    Science.gov (United States)

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  19. Glucose repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kayikci, Omur; Nielsen, Jens

    2015-01-01

    Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluc......Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration...

  20. levadura Saccharomyces Cerevisiae

    Directory of Open Access Journals (Sweden)

    B. Aguilar Uscanga

    2005-01-01

    Full Text Available La pared celular de levaduras representa entre 20 a 30 % de la célula en peso seco. Está compuesta de polisacáridos complejos de β-glucanos, manoproteínas y quitina. Se estudió la composición de los polisacáridos contenidos en la pared celular de la Saccharomyces cerevisiae CEN.PK 113 y se observó el efecto de la variación de la fuente carbono (glucosa, sacarosa, galactosa, maltosa, manosa, etanol y pH (3, 4, 5, 6 en un medio mineral “cell factory”. Las células fueron recolectadas en fase exponencial y se extrajo la pared celular. Los extractos de pared se hidrolizaron con H2SO4 al 72% y las muestras fueron analizadas por cromatografía HPLC. Se realizó una prueba de resistencia al rompimiento celular con una β(1,3-glucanasa, y las células cultivadas a diferentes fuentes carbono y pH. Los resultados del análisis por HPLC, mostraron que la composición de los polisacáridos en la pared celular, varía considerablemente con las modificaciones del medio de cultivo. Se observó que las levaduras cultivadas en sacarosa tienen mayor porcentaje de pared celular (25% y mayor cantidad de glucanos (115µg/mg peso seco y mananos (131µg/mg peso seco, que aquellas levaduras cultivadas en etanol (13% en peso seco. Las levaduras cultivadas a pH 5 presentaron 19% de pared celular en peso seco, mientras que a pH 6 el porcentaje fue menor (14%. El análisis de resistencia al rompimiento celular, mostró que las células cultivadas en etanol y galactosa fueron resistentes al rompimiento enzimático. Se comparó este resultado con el contenido de polisacáridos en la pared celular y concluimos que la resistencia de la célula al rompimiento, no está ligada con la cantidad de β-glucanos contenidos en la pared celular, sino que va a depender del número de enlaces β(1,3 y β(1,6-glucanos, los cuales juegan un rol importante durante el ensamblaje de la pared

  1. E. Coli and Pregnancy

    Science.gov (United States)

    ... chat Live Help Fact Sheets Share Escherichia coli (E. coli) Friday, 01 September 2017 In every pregnancy, a ... risk. This sheet talks about whether exposure to E. coli may increase the risk for birth defects over ...

  2. E coli enteritis

    Science.gov (United States)

    ... coli; Food poisoning - E. coli; E. coli diarrhea; Hamburger disease ... coleslaw or potato salad) that have been out of the refrigerator too ... reheated Fish or oysters Raw fruits or vegetables that have ...

  3. Growth inhibition of S. cerevisiae, B. subtilis, and E. coli by lignocellulosic and fermentation products

    NARCIS (Netherlands)

    Carvalho Pereira, Joana P.C.; Verheijen, P.J.T.; Straathof, Adrie J.J.

    2016-01-01

    This paper describes the effect of several inhibiting components on three potential hosts for the bio-based production of methyl propionate, namely, wild-type Escherichia coli and Bacillus subtilis, and evolved Saccharomyces cerevisiae IMS0351. The inhibition by the lignocellulose-derived

  4. Ethanol production from Jerusalem artichoke by strains of Saccharomyces cheresiensis and Saccharomyces beticus

    Energy Technology Data Exchange (ETDEWEB)

    Pourrat, H.; Barthomeuf, C.; Regerat, F.; Carnat, A.P.; Carnat, A.

    1983-03-01

    Ethanol production from Jerusalem artichoke which is the most interesting autochtonous material has been studied. Two selected and acclimatised strains of Saccharomyces: Saccharomyces cheresiensis and Saccharomyces beticus were retained. The fermentation conditions, exactly definited, makes it possible to obtain in 4 days a theoric yield.

  5. Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities

    Directory of Open Access Journals (Sweden)

    Martinez Alfredo

    2008-05-01

    Full Text Available Abstract Background A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14 derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDCZm and ADHZm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis. It is suggested that this behavior might be due to lineage differences between E. coli W and C. Results This study demonstrated that the glycolytic flux is controlled, in this case, by reactions outside glycolysis, i.e., the fermentative pathways. Changes in ethanol production rate in this ethanologenic strain result in low organic acid production rates, and high glycolytic and ethanologenic fluxes, that correlate with enhanced transcription and enzymatic activity levels of PDCZm and ADHZm. Furthermore, a higher ethanol yield (90% of the theoretical in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions. Conclusion Results suggest that a higher ethanol formation rate, caused by ahigher PDCZm and ADHZm activities induces a metabolic state that cells compensate through enhanced glucose transport, ATP synthesis, and NAD-NADH+H turnover rates. These results show that glycolytic enzymatic activities, present in E. coli W and C under fermentative conditions, are sufficient to contend with increases in glucose consumption and product formation rates.

  6. On cycles in the transcription network of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Berman Piotr

    2008-01-01

    Full Text Available Abstract Background We investigate the cycles in the transcription network of Saccharomyces cerevisiae. Unlike a similar network of Escherichia coli, it contains many cycles. We characterize properties of these cycles and their place in the regulatory mechanism of the cell. Results Almost all cycles in the transcription network of Saccharomyces cerevisiae are contained in a single strongly connected component, which we call LSCC (L for "largest", except for a single cycle of two transcription factors. The fact that LSCC includes almost all cycles is well explained by the properties of a random graph with the same in- and out-degrees of the nodes. Among different physiological conditions, cell cycle has the most significant relationship with LSCC, as the set of 64 transcription interactions that are active in all phases of the cell cycle has overlap of 27 with the interactions of LSCC (of which there are 49. Conversely, if we remove the interactions that are active in all phases of the cell cycle (25% of interactions to transcription factors, the LSCC would have only three nodes and 5 edges, many fewer than expected. This subgraph of the transcription network consists mostly of interactions that are active only in the stress response subnetwork. We also characterize the role of LSCC in the topology of the network. We show that LSCC can be used to define a natural hierarchy in the network and that in every physiological subnetwork LSCC plays a pivotal role. Conclusion Apart from those well-defined conditions, the transcription network of Saccharomyces cerevisiae is devoid of cycles. It was observed that two conditions that were studied and that have no cycles of their own are exogenous: diauxic shift and DNA repair, while cell cycle and sporulation are endogenous. We claim that in a certain sense (slow recovery stress response is endogenous as well.

  7. Escherichia coli pathotypes

    Science.gov (United States)

    Escherichia coli strains are important commensals of the intestinal tract of humans and animals; however, pathogenic strains, including diarrhea-inducing E. coli and extraintestinal pathogenic E. coli. Intestinal E. coli pathotypes may cause a dehydrating watery diarrhea, or more severe diseases su...

  8. In vitro screening of probiotic properties of Saccharomyces cerevisiae var. boulardii and food-borne Saccharomyces cerevisiae strains.

    Science.gov (United States)

    van der Aa Kühle, Alis; Skovgaard, Kerstin; Jespersen, Lene

    2005-05-01

    The probiotic potential of 18 Saccharomyces cerevisiae strains used for production of foods or beverages or isolated from such, and eight strains of Saccharomyces cerevisiae var. boulardii, was investigated. All strains included were able to withstand pH 2.5 and 0.3% Oxgall. Adhesion to the nontumorigenic porcine jejunal epithelial cell line (IPEC-J2) was investigated by incorporation of 3H-methionine into the yeast cells and use of liquid scintillation counting. Only few of the food-borne S. cerevisiae strains exhibited noteworthy adhesiveness with the strongest levels of adhesion (13.6-16.8%) recorded for two isolates from blue veined cheeses. Merely 25% of the S. cerevisiae var. boulardii strains displayed good adhesive properties (16.2-28.0%). The expression of the proinflammatory cytokine IL-1alpha decreased strikingly in IPEC-J2 cells exposed to a Shiga-like toxin 2e producing Escherichia coli strain when the cells were pre- and coincubated with S. cerevisiae var. boulardii even though this yeast strain was low adhesive (5.4%), suggesting that adhesion is not a mandatory prerequisite for such a probiotic effect. A strain of S. cerevisiae isolated from West African sorghum beer exerted similar effects hence indicating that food-borne strains of S. cerevisiae may possess probiotic properties in spite of low adhesiveness.

  9. Effects of fermentation by Saccharomyces cerevisiae and ...

    African Journals Online (AJOL)

    yassine

    2013-02-13

    Feb 13, 2013 ... Full Length Research Paper. Effect of Saccharomyces cerevisiae fermentation on the ... 2003). Besides, several alcoholic beverages such as wine or liqueurs are obtained from fruit juices fermented by Saccharomyces ..... (2003). Kinetics of pigment release from hairy root cultures of Beta vulgaris under the ...

  10. Saccharomyces species in the Production of Beer

    Directory of Open Access Journals (Sweden)

    Graham G. Stewart

    2016-12-01

    Full Text Available The characteristic flavour and aroma of any beer is, in large part, determined by the yeast strain employed and the wort composition. In addition, properties such as flocculation, wort fermentation ability (including the uptake of wort sugars, amino acids, and peptides, ethanol and osmotic pressure tolerance together with oxygen requirements have a critical impact on fermentation performance. Yeast management between fermentations is also a critical brewing parameter. Brewer’s yeasts are mostly part of the genus Saccharomyces. Ale yeasts belong to the species Saccharomyces cerevisiae and lager yeasts to the species Saccharomyces pastorianus. The latter is an interspecies hybrid between S. cerevisiae and Saccharomyces eubayanus. Brewer’s yeast strains are facultative anaerobes—they are able to grow in the presence or absence of oxygen and this ability supports their property as an important industrial microorganism. This article covers important aspects of Saccharomyces molecular biology, physiology, and metabolism that is involved in wort fermentation and beer production.

  11. Repair of UV-irradiated plasmid DNA in excision repair deficient mutants of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ikai, K.; Tano, K.; Ohnishi, T.; Nozu, K.

    1985-01-01

    The repair of UV-irradiated DNA of plasmid YEp13 was studied in the incision defective strains by measurement of cell transformation frequency. In Saccharomyces cerevisiae, rad1,2,3 and 4 mutants could repair UV-damaged plasmid DNA. In Escherichia coli, uvrA mutant was unable to repair UV-damaged plasmid DNA; however, pretreatment of the plasmid with Micrococcus luteus endonuclease increased repair. It was concluded that all the mutations of yeast were probably limited only to the nuclear DNA. (author)

  12. E. Coli Infections

    Science.gov (United States)

    E. coli is the name of a type of bacteria that lives in your intestines. Most types of E. coli are harmless. However, some types can make you ... type causes travelers' diarrhea. The worst type of E. coli causes bloody diarrhea, and can sometimes cause kidney ...

  13. Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Weinert, Brian Tate; Iesmantavicius, Vytautas; Moustafa, Tarek

    2014-01-01

    Lysine acetylation is a frequently occurring posttranslational modification; however, little is known about the origin and regulation of most sites. Here we used quantitative mass spectrometry to analyze acetylation dynamics and stoichiometry in Saccharomyces cerevisiae. We found that acetylation...

  14. [Protective effect of Saccharomyces boulardii against intestinal mucosal barrier injury in rats with nonalcoholic fatty liver disease].

    Science.gov (United States)

    Liu, Y T; Li, Y Q; Wang, Y Z

    2016-12-20

    Objective: To investigate the protective effect of Saccharomyces boulardii against intestinal mucosal barrier injury in rats with nonalcoholic fatty liver disease (NAFLD). Methods: A total of 36 healthy male Sprague-Dawley rats with a mean body weight of 180±20 g were randomly divided into control group, model group, and treatment group, with 12 rats in each group, after adaptive feeding for 1 week. The rats in the control group were given basic feed, and those in the model group and treatment group were given high-fat feed. After 12 weeks of feeding, the treatment group was given Saccharomyces boulardii (75×10 8 CFU/kg/d) by gavage, and those in the control group and model group were given isotonic saline by gavage. At the 20th week, blood samples were taken from the abdominal aorta to measure the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), intestinal fatty acid binding protein (IFABP), tumor necrosis factor-α (TNF-α), and endotoxins. The liver pathological changes, intestinal histopathological changes, and expression of occludin in the intestinal mucosa were observed. Fecal samples were collected to measure the changes in Escherichia coli and Bacteroides. A one-way analysis of variance and the SNK test were used for comparison between multiple groups, and the rank sum test was used as the non-parametric test. Results: Compared with the control group, the model group had significantly higher body weight, liver mass, and liver index ( P 0.05). Compared with the control group, the model group had significant increases in the levels of endotoxin, TNF-α, and IFABP ( P Saccharomyces boulardii can reduce body weight and improve hepatocyte steatosis. Saccharomyces boulardii can reduce endotoxemia in NAFLD rats and thus alleviate inflammatory response. Saccharomyces boulardii can also adjust the proportion of Escherichia coli and Bacteroides in the intestine of NAFLD rats.

  15. Glucose repression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Kayikci, Ömur; Nielsen, Jens

    2015-09-01

    Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective at post-transcriptional and post-translational levels. This review describes effects of glucose repression on yeast carbon metabolism with a focus on roles of the Snf3/Rgt2 glucose-sensing pathway and Snf1 signal transduction in establishment and relief of glucose repression. © FEMS 2015.

  16. Metabolic Engineering of Probiotic Saccharomyces boulardii

    OpenAIRE

    Liu, Jing-Jing; Kong, In Iok; Zhang, Guo-Chang; Jayakody, Lahiru N.; Kim, Heejin; Xia, Peng-Fei; Kwak, Suryang; Sung, Bong Hyun; Sohn, Jung-Hoon; Walukiewicz, Hanna E.; Rao, Christopher V.; Jin, Yong-Su

    2016-01-01

    Saccharomyces boulardii is a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae. Therefore, S. boulardii is an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for...

  17. Saccharomyces genome database informs human biology

    OpenAIRE

    Skrzypek, Marek S; Nash, Robert S; Wong, Edith D; MacPherson, Kevin A; Hellerstedt, Sage T; Engel, Stacia R; Karra, Kalpana; Weng, Shuai; Sheppard, Travis K; Binkley, Gail; Simison, Matt; Miyasato, Stuart R; Cherry, J Michael

    2017-01-01

    Abstract The Saccharomyces Genome Database (SGD; http://www.yeastgenome.org) is an expertly curated database of literature-derived functional information for the model organism budding yeast, Saccharomyces cerevisiae. SGD constantly strives to synergize new types of experimental data and bioinformatics predictions with existing data, and to organize them into a comprehensive and up-to-date information resource. The primary mission of SGD is to facilitate research into the biology of yeast and...

  18. 2μ plasmid in Saccharomyces species and in Saccharomyces cerevisiae.

    Science.gov (United States)

    Strope, Pooja K; Kozmin, Stanislav G; Skelly, Daniel A; Magwene, Paul M; Dietrich, Fred S; McCusker, John H

    2015-12-01

    We determined that extrachromosomal 2μ plasmid was present in 67 of the Saccharomyces cerevisiae 100-genome strains; in addition to variation in the size and copy number of 2μ, we identified three distinct classes of 2μ. We identified 2μ presence/absence and class associations with populations, clinical origin and nuclear genotypes. We also screened genome sequences of S. paradoxus, S. kudriavzevii, S. uvarum, S. eubayanus, S. mikatae, S. arboricolus and S. bayanus strains for both integrated and extrachromosomal 2μ. Similar to S. cerevisiae, we found no integrated 2μ sequences in any S. paradoxus strains. However, we identified part of 2μ integrated into the genomes of some S. uvarum, S. kudriavzevii, S. mikatae and S. bayanus strains, which were distinct from each other and from all extrachromosomal 2μ. We identified extrachromosomal 2μ in one S. paradoxus, one S. eubayanus, two S. bayanus and 13 S. uvarum strains. The extrachromosomal 2μ in S. paradoxus, S. eubayanus and S. cerevisiae were distinct from each other. In contrast, the extrachromosomal 2μ in S. bayanus and S. uvarum strains were identical with each other and with one of the three classes of S. cerevisiae 2μ, consistent with interspecific transfer. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

    OpenAIRE

    ANGGREINI, RAHAYU

    2015-01-01

    2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.

  20. Probiotic Activity of Saccharomyces cerevisiae var. boulardii Against Human Pathogens

    Directory of Open Access Journals (Sweden)

    Katarzyna Rajkowska

    2012-01-01

    Full Text Available Infectious diarrhoea is associated with a modification of the intestinal microflora and colonization of pathogenic bacteria. Tests were performed for seven probiotic yeast strains of Saccharomyces cerevisiae var. boulardii, designated for the prevention and treatment of diarrhoea. To check their possible effectiveness against diarrhoea of different etiologies, the activity against a variety of human pathogenic or opportunistic bacteria was investigated in vitro. In mixed cultures with S. cerevisiae var. boulardii, a statistically significant reduction was observed in the number of cells of Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus, by even 55.9 % in the case of L. monocytogenes compared with bacterial monocultures. The influence of yeasts was mostly associated with the shortening of the bacterial lag phase duration, more rapid achievement of the maximum growth rates, and a decrease by 4.4–57.1 % (L. monocytogenes, P. aeruginosa, or an increase by 1.4–70.6 % (Escherichia coli, Enterococcus faecalis, Salmonella Typhimurium in the exponential growth rates. Another issue included in the research was the ability of S. cerevisiae var. boulardii to bind pathogenic bacteria to its cell surface. Yeasts have shown binding capacity of E. coli, S. Typhimurium and additionally of S. aureus, Campylobacter jejuni and E. faecalis. However, no adhesion of L. monocytogenes and P. aeruginosa to the yeast cell wall was noted. The probiotic activity of S. cerevisiae var. boulardii against human pathogens is related to a decrease in the number of viable and active cells of bacteria and the binding capacity of yeasts. These processes may limit bacterial invasiveness and prevent bacterial adherence and translocation in the human intestines.

  1. Conjugation in Escherichia coli

    Science.gov (United States)

    Boyer, Herbert

    1966-01-01

    Boyer, Herbert (Yale University, New Haven, Conn.). Conjugation in Escherichia coli. J. Bacteriol. 91:1767–1772. 1966.—The sex factor of Escherichia coli K-12 was introduced into an E. coli B/r strain by circumventing the host-controlled modification and restriction incompatibilities known to exist between these closely related strains. The sexual properties of the constructed F+ B strain and its Hfr derivatives were examined. These studies showed that the E. coli strain B/r F+ and Hfr derivatives are similar to the E. coli strain K-12 F+ and Hfr derivatives. However, the site of sex factor integration was found to be dependent on the host genome. PMID:5327905

  2. Enzymatic activities produced by mixed Saccharomyces and non-Saccharomyces cultures: relationship with wine volatile composition.

    Science.gov (United States)

    Maturano, Yolanda Paola; Assof, Mariela; Fabani, María Paula; Nally, María Cristina; Jofré, Viviana; Rodríguez Assaf, Leticia Anahí; Toro, María Eugenia; Castellanos de Figueroa, Lucía Inés; Vazquez, Fabio

    2015-11-01

    During certain wine fermentation processes, yeasts, and mainly non-Saccharomyces strains, produce and secrete enzymes such as β-glucosidases, proteases, pectinases, xylanases and amylases. The effects of enzyme activity on the aromatic quality of wines during grape juice fermentation, using different co-inoculation strategies of non-Saccharomyces and Saccharomyces cerevisiae yeasts, were assessed in the current study. Three strains with appropriate enological performance and high enzymatic activities, BSc562 (S. cerevisiae), BDv566 (Debaryomyces vanrijiae) and BCs403 (Candida sake), were assayed in pure and mixed Saccharomyces/non-Saccharomyces cultures. β-Glucosidase, pectinase, protease, xylanase and amylase activities were quantified during fermentations. The aromatic profile of pure and mixed cultures was determined at the end of each fermentation. In mixed cultures, non-Saccharomyces species were detected until day 4-5 of the fermentation process, and highest populations were observed in MSD2 (10% S. cerevisiae/90% D. vanrijiae) and MSC1 (1% S. cerevisiae/99% C. sake). According to correlation and multivariate analysis, MSD2 presented the highest concentrations of terpenes and higher alcohols which were associated with pectinase, amylase and xylanase activities. On the other hand, MSC1 high levels of β-glucosidase, proteolytic and xylanolytic activities were correlated to esters and fatty acids. Our study contributes to a better understanding of the effect of enzymatic activities by yeasts on compound transformations that occur during wine fermentation.

  3. Fatty acid metabolism in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    van Roermund, C. W. T.; Waterham, H. R.; IJlst, L.; Wanders, R. J. A.

    2003-01-01

    Peroxisomes are essential subcellular organelles involved in a variety of metabolic processes. Their importance is underlined by the identification of a large group of inherited diseases in humans in which one or more of the peroxisomal functions are impaired. The yeast Saccharomyces cerevisiae has

  4. Ferrofluid modified Saccharomyces cerevisiae cells for biocatalysis

    Czech Academy of Sciences Publication Activity Database

    Šafaříková, Miroslava; Maděrová, Zdeňka; Šafařík, Ivo

    2009-01-01

    Roč. 42, - (2009), s. 521-524 ISSN 0963-9969 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk(CZ) OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : Saccharomyces cerevisiae * magnetic fluid * hydrogen peroxide Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.414, year: 2009

  5. Nitrogen Catabolite Repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider

    1999-01-01

    In Saccharomyces cerevisiae the expression of all known nitrogen catabolite pathways are regulated by four regulators known as Gln3, Gat1, Da180, and Deh1. This is known as nitrogen catabolite repression (NCR). They bind to motifs in the promoter region to the consensus sequence S' GATAA 3'. Gln3...

  6. Fatal Saccharomyces Cerevisiae Aortic Graft Infection

    Science.gov (United States)

    Meyer, Michael (Technical Monitor); Smith, Davey; Metzgar, David; Wills, Christopher; Fierer, Joshua

    2002-01-01

    Saccharomyces cerevisiae is a yeast commonly used in baking and a frequent colonizer of human mucosal surfaces. It is considered relatively nonpathogenic in immunocompetent adults. We present a case of S. cerevisiae fungemia and aortic graft infection in an immunocompetent adult. This is the first reported case of S. cerevisiue fungemia where the identity of the pathogen was confirmed by rRNA sequencing.

  7. Regulation of trehalose metabolism in Saccharomyces

    International Nuclear Information System (INIS)

    Panek, A.D.; Costa-Carvalho, V.L.A.; Ortiz, C.H.D.; Dellamora-Ortiz, G.M.; Paschoalin, V.M.F.; Panek, A.C.

    1984-01-01

    The regulation of trehalose metabolism in Saccharomyces is studied by construction of mutants with specific lesions, cloning of genes involved in the regulation of trehalose synthase and of trehalase, as well as, isolation and purification of enzymes from the various mutants constructed. (M.A.C.) [pt

  8. Characterisation of Saccharomyces cerevisiae hybrids selected for ...

    African Journals Online (AJOL)

    Wine yeasts (Saccharomyces cerevisiae) vary in their ability to develop the full aroma potential of Sauvignon blanc wine due to an inability to release volatile thiols. Subsequently, the use of 'thiolreleasing' wine yeasts (TRWY) has increased in popularity. However, anecdotal evidence suggests that some commercially ...

  9. Hybridization of Palm Wine Yeasts ( Saccharomyces Cerevisiae ...

    African Journals Online (AJOL)

    Haploid auxotrophic strains of Saccharomyces cerevisiae were selected from palm wine and propagated by protoplast fusion with Brewers yeast. Fusion resulted in an increase in both ethanol production and tolerance against exogenous ethanol. Mean fusion frequencies obtained for a mating types ranged between 8 x ...

  10. Substrate Channelling and Energetics of Saccharomyces cerevisiae ...

    African Journals Online (AJOL)

    Data collected during the high-cell-density cultivation of Saccharomyces cerevisiae DSM 2155 on glucose in a simulated five-phase feeding strategy of fed-batch process, executed on the Universal BIoprocess CONtrol (UBICON) system using 150L bioreactor over a period of 24h have been analysed. The consistency of the ...

  11. Enterohemorrhagic Escherichia coli (EHEC

    Directory of Open Access Journals (Sweden)

    Abdullah Kilic

    2011-08-01

    Full Text Available Escherichia coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless for human. E. coli O157:H7 is the most common member of a group of pathogenic E. coli strains known variously as enterohaemorrhagic, verocytotoxin-producing, or Shiga-toxin-producing organisms. EHEC bacterium is the major cause of haemorrhagic colitis and haemolytic uraemic syndrome. The reservoir of this pathogen appears to be mainly cattle and other ruminants such as camels. It is transmitted to humans primarily through consumption of contaminated foods. [TAF Prev Med Bull 2011; 10(4.000: 387-388

  12. Can E. coli fly?

    DEFF Research Database (Denmark)

    Lindeberg, Yrja Lisa; Egedal, Karen; Hossain, Zenat Zebin

    2018-01-01

    , and the numbers of flies landing on the exposed rice were counted. Following exposure, the surface of the rice was microbiologically and molecularly analysed for the presence of E. coli and genes of diarrheagenic E. coli and Shigella strains. RESULTS: Rice was at greater risk (p ... with E. coli if flies landed on the rice than if no flies landed on the rice (odds ratio 5·4 (p ...-landings, the average CFU per fly-landing was > 0·6 x 103 CFU. Genes of diarrheagenic E. coli and Shigella species were detected in 39 of 60 (65%) of exposed rice samples. Two fly species were identified; the common housefly (Musca domestica) and the oriental latrine fly (Chrysomya megacephala). CONCLUSION: Flies may...

  13. Endogenous E. coli endophthalmitis.

    Science.gov (United States)

    Shammas, H F

    1977-01-01

    A case of Escherichia coli septicemia with associated metastatic en dophthalmitis and endocarditis is presented. The ocular signs and symptoms were the initial manifestations of sepsis. Irreversible damage to the eye occurred in less than 24 hours. The pattern of metastatic bacterial endophthalmitis has changed since the introduction of potent antimicrobial agents, with an increased incidence of Gram-negative bacillemia. E. coli endophthalmitis carries a poor prognosis. Early diagnosis and systemic treatment will prevent the life-threatening complications of sepsis.

  14. Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol

    Energy Technology Data Exchange (ETDEWEB)

    Steen, EricJ.; Chan, Rossana; Prasad, Nilu; Myers, Samuel; Petzold, Christopher; Redding, Alyssa; Ouellet, Mario; Keasling, JayD.

    2008-11-25

    BackgroundIncreasing energy costs and environmental concerns have motivated engineering microbes for the production of ?second generation? biofuels that have better properties than ethanol.Results& ConclusionsSaccharomyces cerevisiae was engineered with an n-butanol biosynthetic pathway, in which isozymes from a number of different organisms (S. cerevisiae, Escherichia coli, Clostridium beijerinckii, and Ralstonia eutropha) were substituted for the Clostridial enzymes and their effect on n-butanol production was compared. By choosing the appropriate isozymes, we were able to improve production of n-butanol ten-fold to 2.5 mg/L. The most productive strains harbored the C. beijerinckii 3-hydroxybutyryl-CoA dehydrogenase, which uses NADH as a co-factor, rather than the R. eutropha isozyme, which uses NADPH, and the acetoacetyl-CoA transferase from S. cerevisiae or E. coli rather than that from R. eutropha. Surprisingly, expression of the genes encoding the butyryl-CoA dehydrogenase from C. beijerinckii (bcd and etfAB) did not improve butanol production significantly as previously reported in E. coli. Using metabolite analysis, we were able to determine which steps in the n-butanol biosynthetic pathway were the most problematic and ripe for future improvement.

  15. The Saccharomyces Genome Database Variant Viewer.

    Science.gov (United States)

    Sheppard, Travis K; Hitz, Benjamin C; Engel, Stacia R; Song, Giltae; Balakrishnan, Rama; Binkley, Gail; Costanzo, Maria C; Dalusag, Kyla S; Demeter, Janos; Hellerstedt, Sage T; Karra, Kalpana; Nash, Robert S; Paskov, Kelley M; Skrzypek, Marek S; Weng, Shuai; Wong, Edith D; Cherry, J Michael

    2016-01-04

    The Saccharomyces Genome Database (SGD; http://www.yeastgenome.org) is the authoritative community resource for the Saccharomyces cerevisiae reference genome sequence and its annotation. In recent years, we have moved toward increased representation of sequence variation and allelic differences within S. cerevisiae. The publication of numerous additional genomes has motivated the creation of new tools for their annotation and analysis. Here we present the Variant Viewer: a dynamic open-source web application for the visualization of genomic and proteomic differences. Multiple sequence alignments have been constructed across high quality genome sequences from 11 different S. cerevisiae strains and stored in the SGD. The alignments and summaries are encoded in JSON and used to create a two-tiered dynamic view of the budding yeast pan-genome, available at http://www.yeastgenome.org/variant-viewer. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Beneficial properties of probiotic yeast Saccharomyces boulardii

    OpenAIRE

    Tomičić Zorica M.; Čolović Radmilo R.; Čabarkapa Ivana S.; Vukmirović Đuro M.; Đuragić Olivera M.; Tomičić Ružica M.

    2016-01-01

    Saccharomyces boulardii is unique probiotic and biotherapeutic yeast, known to survive in gastric acidity and it is not adversely affected or inhibited by antibiotics or does not alter or adversely affect the normal microbiota. S. boulardii has been utilized worldwide as a probiotic supplement to support gastrointestinal health. The multiple mechanisms of action of S. boulardii and its properties may explain its efficacy and beneficial effects in acute and chronic gastrointestinal diseases th...

  17. Saccharomyces cerevisiae metabolism in ecological context

    OpenAIRE

    Jouhten, Paula; Ponomarova, Olga; González García, Ramón; Patil, Kiran R.

    2016-01-01

    The architecture and regulation of Saccharomyces cerevisiae metabolic network are among the best studied owing to its widespread use in both basic research and industry. Yet, several recent studies have revealed notable limitations in explaining genotype?metabolic phenotype relations in this yeast, especially when concerning multiple genetic/environmental perturbations. Apparently unexpected genotype?phenotype relations may originate in the evolutionarily shaped cellular operating principles ...

  18. Studies of Saccharomyces cerevisiae and Non-Saccharomyces Yeasts during Alcoholic Fermentation

    DEFF Research Database (Denmark)

    Kemsawasd, Varongsiri

    The early death of non-Saccharomyces yeasts during mixed culture spontaneous wine fermentation has traditionally been attributed to the lower capacity of these yeast species to withstand high levels of ethanol, low pH, and other media properties that are a part of progressing fermentation. However......, other yeast-yeast interactions, such as cell-cell contact mediated growth arrest and/or toxininduced death may also be a significant factor in the relative fragility of these non-Saccharomyces yeasts in mixed culture fermentation. In the present work we evaluate the combined roles of cell-cell contact...... and/or antimicrobial peptides on the early death of Lachancea thermotolerans during mixed culture fermentations with Saccharomyces cerevisiae. Using a specially designed double compartment fermentation system, we established that both cell-to-cell contact and antimicrobial peptides contribute...

  19. Thioredoxin from Escherichia coli

    International Nuclear Information System (INIS)

    Holmgren, A.; Ohlsson, I.; Grankvist, M.L.

    1978-01-01

    A competition radioimmunoassay for Escherichia coli thioredoxin using 125 I-labeled thioredoxin-S 2 and a double antibody technique was developed. The method permits determination of picomole amounts of thioredoxin in crude cell extracts and was used to study the localization of thioredoxin cell fractions. E. coli B was calculated to have approximately 10,000 copies of thioredoxin per cell mainly located in the soluble fraction after separation of the membrane and soluble fractions by gentle lysis and centrifugation. E. coli B tsnC mutants which are defective in the replication of phage T7 DNA in vivo and in vitro were examined for their content of thioredoxin. E. coli B tsnC 7004 contained no detectable level of thioredoxin in cell-free extracts examined under a variety of conditions. The results strongly suggest that tsnC 7004 is a nonsense or deletion mutant. Two other E. coli tsnC mutants, 7007 and 7008, contained detectable levels of thioredoxin in crude extracts as measured by thioredoxin reductase and gave similar immunoprecipitation reactions as the parent strain B/1. By radioimmunoassay incompletely cross-reacting material was present in both strains. These results show that tsnC 7007 and 7008 belong to a type of thioredoxin mutants with missence mutations in the thioredoxin gene affecting the function of thioredoxin as subunit in phage T7 DNA polymerase

  20. Lactose/whey utilization and ethanol production by transformed Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Porro, D; Martegani, E; Ranzi, B M; Alberghina, L

    1992-04-05

    Strains of Saccharomyces cerevisiae transformed with a multicopy expression vector bearing both the Escherichia coli beta-galactosidase gene under the control of the upstream activating sequence of the GAL1-10 genes and the GAL4 activator gene release part of beta-galactosidase in the growth medium. This release is due to cell lysis of the older mother cells; the enzyme maintains its activity in buffered growth media. Fermentation studies with transformed yeast strains showed that the release of beta-galactosidase allowed an efficient growth on buffered media containing lactose as carbon source as well as on whey-based media. The transformed strains utilized up to 95% of the lactose and a high growth yield was obtained in rich media. High productions of ethanol were also observed in stationary phase after growth in lactose minimal media.

  1. Photodynamic DNA damage induced by phycocyanin and its repair in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    M. Pádula

    1999-09-01

    Full Text Available In the present study, we analyzed DNA damage induced by phycocyanin (PHY in the presence of visible light (VL using a set of repair endonucleases purified from Escherichia coli. We demonstrated that the profile of DNA damage induced by PHY is clearly different from that induced by molecules that exert deleterious effects on DNA involving solely singlet oxygen as reactive species. Most of PHY-induced lesions are single strand breaks and, to a lesser extent, base oxidized sites, which are recognized by Nth, Nfo and Fpg enzymes. High pressure liquid chromatography coupled to electrochemical detection revealed that PHY photosensitization did not induce 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo at detectable levels. DNA repair after PHY photosensitization was also investigated. Plasmid DNA damaged by PHY photosensitization was used to transform a series of Saccharomyces cerevisiae DNA repair mutants. The results revealed that plasmid survival was greatly reduced in rad14 mutants, while the ogg1 mutation did not modify the plasmid survival when compared to that in the wild type. Furthermore, plasmid survival in the ogg1 rad14 double mutant was not different from that in the rad14 single mutant. The results reported here indicate that lethal lesions induced by PHY plus VL are repaired differently by prokaryotic and eukaryotic cells. Morever, nucleotide excision repair seems to play a major role in the recognition and repair of these lesions in Saccharomyces cerevisiae.

  2. escherichia coli serotypes confirmed in experimental mammary ...

    African Journals Online (AJOL)

    DJFLEX

    VARIATIONS IN VIRULENCE OF THREE (3) ESCHERICHIA COLI. SEROTYPES CONFIRMED IN ... ows are susceptible to E. coli infection because. E. coli exist in the .... Coli infections in mice: A laboratory animal model for research in.

  3. Functional expression of rat VPAC1 receptor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hansen, M.K.; Tams, J.W.; Fahrenkrug, Jan

    1999-01-01

    G protein-coupled receptor; heterologous expression; membrane protein; Saccharomyces cerevisiae, vasoactive intestinal polypeptide; yeast mating factor-pre-pro *Ga-leader peptide......G protein-coupled receptor; heterologous expression; membrane protein; Saccharomyces cerevisiae, vasoactive intestinal polypeptide; yeast mating factor-pre-pro *Ga-leader peptide...

  4. Investigation of autonomous cell cycle oscillation in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hansen, Morten Skov

    2007-01-01

    Autonome Oscillationer i kontinuert kultivering af Saccharomyces cerevisiae Udgangspunktet for dette Ph.d. projekt var at søge at forstå, hvad der gør det muligt at opnå multiple statiske tilstande ved kontinuert kultivering af Saccharomyces cerevisiae med glukose som begrænsende substrat...

  5. The ecology and evolution of non-domesticated Saccharomyces species.

    Science.gov (United States)

    Boynton, Primrose J; Greig, Duncan

    2014-12-01

    Yeast researchers need model systems for ecology and evolution, but the model yeast Saccharomyces cerevisiae is not ideal because its evolution has been affected by domestication. Instead, ecologists and evolutionary biologists are focusing on close relatives of S. cerevisiae, the seven species in the genus Saccharomyces. The best-studied Saccharomyces yeast, after S. cerevisiae, is S. paradoxus, an oak tree resident throughout the northern hemisphere. In addition, several more members of the genus Saccharomyces have recently been discovered. Some Saccharomyces species are only found in nature, while others include both wild and domesticated strains. Comparisons between domesticated and wild yeasts have pinpointed hybridization, introgression and high phenotypic diversity as signatures of domestication. But studies of wild Saccharomyces natural history, biogeography and ecology are only beginning. Much remains to be understood about wild yeasts' ecological interactions and life cycles in nature. We encourage researchers to continue to investigate Saccharomyces yeasts in nature, both to place S. cerevisiae biology into its ecological context and to develop the genus Saccharomyces as a model clade for ecology and evolution. © 2014 The Authors. Yeast published by John Wiley & Sons, Ltd.

  6. Saccharomyces eubayanus and Saccharomyces arboricola reside in North Island native New Zealand forests.

    Science.gov (United States)

    Gayevskiy, Velimir; Goddard, Matthew R

    2016-04-01

    Saccharomyces is one of the best-studied microbial genera, but our understanding of the global distributions and evolutionary histories of its members is relatively poor. Recent studies have altered our view of Saccharomyces' origin, but a lack of sampling from the vast majority of the world precludes a holistic perspective. We evaluate alternate Gondwanan and Far East Asian hypotheses concerning the origin of these yeasts. Being part of Gondwana, and only colonized by humans in the last ∼1000 years, New Zealand represents a unique environment for testing these ideas. Genotyping and ribosomal sequencing of samples from North Island native forest parks identified a widespread population of Saccharomyces. Whole genome sequencing identified the presence of S. arboricola and S. eubayanus in New Zealand, which is the first report of S. arboricola outside Far East Asia, and also expands S. eubayanus' known distribution to include the Oceanic region. Phylogenomic approaches place the S. arboricola population as significantly diverged from the only other sequenced Chinese isolate but indicate that S. eubayanus might be a recent migrant from South America. These data tend to support the Far East Asian origin of the Saccharomyces, but the history of this group is still far from clear. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Saccharomyces eubayanus and Saccharomyces uvarum associated with the fermentation of Araucaria araucana seeds in Patagonia.

    Science.gov (United States)

    Rodríguez, M Eugenia; Pérez-Través, Laura; Sangorrín, Marcela P; Barrio, Eladio; Lopes, Christian A

    2014-09-01

    Mudai is a traditional fermented beverage, made from the seeds of the Araucaria araucana tree by Mapuche communities. The main goal of the present study was to identify and characterize the yeast microbiota responsible of Mudai fermentation as well as from A. araucana seeds and bark from different locations in Northern Patagonia. Only Hanseniaspora uvarum and a commercial bakery strain of Saccharomyces cerevisiae were isolated from Mudai and all Saccharomyces isolates recovered from A. araucana seed and bark samples belonged to the cryotolerant species Saccharomyces eubayanus and Saccharomyces uvarum. These two species were already reported in Nothofagus trees from Patagonia; however, this is the first time that they were isolated from A. araucana, which extends their ecological distribution. The presence of these species in A. araucana seeds and bark samples, led us to postulate a potential role for them as the original yeasts responsible for the elaboration of Mudai before the introduction of commercial S. cerevisiae cultures. The molecular and genetic characterization of the S. uvarum and S. eubayanus isolates and their comparison with European S. uvarum strains and S. eubayanus hybrids (S. bayanus and S. pastorianus), allowed their ecology and evolution us to be examined. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  8. Apoptosis - Triggering Effects: UVB-irradiation and Saccharomyces cerevisiae.

    Science.gov (United States)

    Behzadi, Payam; Behzadi, Elham

    2012-12-01

    The pathogenic disturbance of Saccharomyces cerevisiae is known as a rare but invasive nosocomial fungal infection. This survey is focused on the evaluation of apoptosis-triggering effects of UVB-irradiation in Saccharomyces cerevisiae. The well-growth colonies of Saccharomyces cerevisiae on Sabouraud Dextrose Agar (SDA) were irradiated within an interval of 10 minutes by UVB-light (302 nm). Subsequently, the harvested DNA molecules of control and UV-exposed yeast colonies were run through the 1% agarose gel electrophoresis comprising the luminescent dye of ethidium bromide. No unusual patterns including DNA laddering bands or smears were detected. The applied procedure for UV exposure was not effective for inducing apoptosis in Saccharomyces cerevisiae. So, it needs another UV-radiation protocol for inducing apoptosis phenomenon in Saccharomyces cerevisiae.

  9. Saccharomyces kudriavzevii and Saccharomyces uvarum differ from Saccharomyces cerevisiae during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors.

    Science.gov (United States)

    Stribny, Jiri; Gamero, Amparo; Pérez-Torrado, Roberto; Querol, Amparo

    2015-07-16

    Higher alcohols and acetate esters are important flavour and aroma components in the food industry. In alcoholic beverages these compounds are produced by yeast during fermentation. Although Saccharomyces cerevisiae is one of the most extensively used species, other species of the Saccharomyces genus have become common in fermentation processes. This study analyses and compares the production of higher alcohols and acetate esters from their amino acidic precursors in three Saccharomyces species: Saccharomyces kudriavzevii, Saccharomyces uvarum and S. cerevisiae. The global volatile compound analysis revealed that S. kudriavzevii produced large amounts of higher alcohols, whereas S. uvarum excelled in the production of acetate esters. Particularly from phenylalanine, S. uvarum produced the largest amounts of 2-phenylethyl acetate, while S. kudriavzevii obtained the greatest 2-phenylethanol formation from this precursor. The present data indicate differences in the amino acid metabolism and subsequent production of flavour-active higher alcohols and acetate esters among the closely related Saccharomyces species. This knowledge will prove useful for developing new enhanced processes in fragrance, flavour, and food industries. Copyright © 2015. Published by Elsevier B.V.

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

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

    International Nuclear Information System (INIS)

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

    1983-01-01

    Experiments investigating ultraviolet light mutagenesis in either bakers' yeast, Saccharomyces cerevisiae, or E. coli have led to the following conclusions. First, cyclobutane pyrimidine dimers cause most mutations in both organisms; pyrimidine adducts, such as PyC, can account at best for only a small proportion. Eighty-six percent of forward mutations induced at the E. coli lacI locus can be abolished by photoreactivation under conditions which do not alter the level of recA induction. About 75 percent of the forward mutations induced at the CAN1 locus of yeast could be removed by photoreactivation, a value that lies within the range observed previously for the reversion of CYC1 alleles (60 percent - 97 percent). Second, about 10 percent of the lacI forward mutations are untargeted, a smaller fraction than found previously for cycl1-91 reversion in yeast. It is not yet clear whether the two species are really different in this respect, or whether the cyc1-91 reversion site is atypical of the yeast genome at large. Third, analysis of reversion frequencies of 20 mutant alleles suggests that about 10 - 25 percent of all replication errors produced by mutagenic mechanisms in UV-irradiated yeast involve additions or deletions of base-pairs, indicating that error-prone repair does not just produce substitutions. Last, the REV1 locus in yeast is concerned with the induction of frameshift mutations at some, but not all, genetic sites, just as found previously for substitution mutations. The function of the REV3 gene is more widely, though not universally, required while the function of the RAD6 gene, like that of the recA locus in E. coli, appears to be necessary for all kinds of UV mutagenesis. E. coli genes comparable to REV1 and REV3 have not yet been described, conversely, there does not yet appear to be a yeast equivalent of umuC. 13 references, 4 tables

  12. Functional Diversity of Haloacid Dehalogenase Superfamily Phosphatases from Saccharomyces cerevisiae: BIOCHEMICAL, STRUCTURAL, AND EVOLUTIONARY INSIGHTS.

    Science.gov (United States)

    Kuznetsova, Ekaterina; Nocek, Boguslaw; Brown, Greg; Makarova, Kira S; Flick, Robert; Wolf, Yuri I; Khusnutdinova, Anna; Evdokimova, Elena; Jin, Ke; Tan, Kemin; Hanson, Andrew D; Hasnain, Ghulam; Zallot, Rémi; de Crécy-Lagard, Valérie; Babu, Mohan; Savchenko, Alexei; Joachimiak, Andrzej; Edwards, Aled M; Koonin, Eugene V; Yakunin, Alexander F

    2015-07-24

    The haloacid dehalogenase (HAD)-like enzymes comprise a large superfamily of phosphohydrolases present in all organisms. The Saccharomyces cerevisiae genome encodes at least 19 soluble HADs, including 10 uncharacterized proteins. Here, we biochemically characterized 13 yeast phosphatases from the HAD superfamily, which includes both specific and promiscuous enzymes active against various phosphorylated metabolites and peptides with several HADs implicated in detoxification of phosphorylated compounds and pseudouridine. The crystal structures of four yeast HADs provided insight into their active sites, whereas the structure of the YKR070W dimer in complex with substrate revealed a composite substrate-binding site. Although the S. cerevisiae and Escherichia coli HADs share low sequence similarities, the comparison of their substrate profiles revealed seven phosphatases with common preferred substrates. The cluster of secondary substrates supporting significant activity of both S. cerevisiae and E. coli HADs includes 28 common metabolites that appear to represent the pool of potential activities for the evolution of novel HAD phosphatases. Evolution of novel substrate specificities of HAD phosphatases shows no strict correlation with sequence divergence. Thus, evolution of the HAD superfamily combines the conservation of the overall substrate pool and the substrate profiles of some enzymes with remarkable biochemical and structural flexibility of other superfamily members. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Biocuration at the Saccharomyces genome database.

    Science.gov (United States)

    Skrzypek, Marek S; Nash, Robert S

    2015-08-01

    Saccharomyces Genome Database is an online resource dedicated to managing information about the biology and genetics of the model organism, yeast (Saccharomyces cerevisiae). This information is derived primarily from scientific publications through a process of human curation that involves manual extraction of data and their organization into a comprehensive system of knowledge. This system provides a foundation for further analysis of experimental data coming from research on yeast as well as other organisms. In this review we will demonstrate how biocuration and biocurators add a key component, the biological context, to our understanding of how genes, proteins, genomes and cells function and interact. We will explain the role biocurators play in sifting through the wealth of biological data to incorporate and connect key information. We will also discuss the many ways we assist researchers with their various research needs. We hope to convince the reader that manual curation is vital in converting the flood of data into organized and interconnected knowledge, and that biocurators play an essential role in the integration of scientific information into a coherent model of the cell. © 2015 Wiley Periodicals, Inc.

  14. Metabolic Engineering of Probiotic Saccharomyces boulardii.

    Science.gov (United States)

    Liu, Jing-Jing; Kong, In Iok; Zhang, Guo-Chang; Jayakody, Lahiru N; Kim, Heejin; Xia, Peng-Fei; Kwak, Suryang; Sung, Bong Hyun; Sohn, Jung-Hoon; Walukiewicz, Hanna E; Rao, Christopher V; Jin, Yong-Su

    2016-04-01

    Saccharomyces boulardiiis a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae Therefore, S. boulardiiis an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for metabolic engineering. Here, we report the development of well-defined auxotrophic mutants (leu2,ura3,his3, and trp1) through clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-based genome editing. The resulting auxotrophic mutants can be used as a host for introducing various genetic perturbations, such as overexpression or deletion of a target gene, using existing genetic tools forS. cerevisiae We demonstrated the overexpression of a heterologous gene (lacZ), the correct localization of a target protein (red fluorescent protein) into mitochondria by using a protein localization signal, and the introduction of a heterologous metabolic pathway (xylose-assimilating pathway) in the genome ofS. boulardii We further demonstrated that human lysozyme, which is beneficial for human gut health, could be secreted by S. boulardii Our results suggest that more sophisticated genetic perturbations to improveS. boulardii can be performed without using a drug resistance marker, which is a prerequisite for in vivo applications using engineeredS. boulardii. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. PART I. ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Sanaa Mahdi Oraibi

    2016-11-01

    Full Text Available The presence of Escherichia coli in the air of facilities involved in management and composting of post-slaughter poultry wastes in selected plants of West Western Pomerania region was studied. Measurements were made on four dates in a variety of weather conditions during the year. The study was conducted at 5 objects that differ in the type of waste and the degree of preparation for composting. These were: chemical treatment and preliminary processing plant, liquid wastes reservoir, platform for preparation of materials for composting, storage of biological sediments, and composting facility. Measurement of bacteria count was carried out in accordance with the applicable procedures on selective chromogenic TBX medium. The assays revealed the presence of E. coli at all test objects, but not always on all measurement dates. It has been shown that the presence of E. coli was from 20 to 3047 CFU∙m-3 of air, although the largest quantities were most frequently detected in the air of the building for post-slaughter waste pre-treatment in chemical treatment plant.

  16. Genomic insights into the Saccharomyces sensu stricto complex.

    Science.gov (United States)

    Borneman, Anthony R; Pretorius, Isak S

    2015-02-01

    The Saccharomyces sensu stricto group encompasses species ranging from the industrially ubiquitous yeast Saccharomyces cerevisiae to those that are confined to geographically limited environmental niches. The wealth of genomic data that are now available for the Saccharomyces genus is providing unprecedented insights into the genomic processes that can drive speciation and evolution, both in the natural environment and in response to human-driven selective forces during the historical "domestication" of these yeasts for baking, brewing, and winemaking. Copyright © 2015 by the Genetics Society of America.

  17. Saccharomyces cerevisiae var. boulardii fungemia following probiotic treatment

    Directory of Open Access Journals (Sweden)

    Marcelo C. Appel-da-Silva

    2017-12-01

    Full Text Available Probiotics are commonly prescribed as an adjuvant in the treatment of antibiotic-associated diarrhea caused by Clostridium difficile. We report the case of an immunocompromised 73-year-old patient on chemotherapy who developed Saccharomyces cerevisiae var. boulardii fungemia in a central venous catheter during treatment of antibiotic-associated pseudomembranous colitis with the probiotic Saccharomyces cerevisiae var. boulardii. Fungemia was resolved after interruption of probiotic administration without the need to replace the central venous line. Keywords: Saccharomyces, Probiotics, Fungemia, Critical illness, Clostridium difficile

  18. Evaluation of different co-inoculation time of non-Saccharomyces/Saccharomyces yeasts in order to obtain reduced ethanol wines

    Directory of Open Access Journals (Sweden)

    Mestre María Victoria

    2016-01-01

    Full Text Available Decreasing ethanol content in wines has become one of the main objectives of winemakers in different areas of the world. The use of selected wine yeasts can be considered one of the most effective and simple tools. The aim of this study was to evaluate the effect of co-inoculation times of selected non-Saccharomyces/Saccharomyces yeasts on the reduction of ethanol levels in wines. Hanseniaspora uvarum BHu9, Starmerella bacillaris BSb55 and Candida membranaefasciens BCm71 were co-inoculate with Saccharomyces cerevisiae under fermentative conditions. Treatments assayed were: pure fermentations of S. cerevisiae BSc203 and non-Saccharomyces yeasts BHu9, BSb55 and BCm71; -co-fermentations: A-BHu9/BSc203; B-BSb55/BSc203 and C-BCm71/BSc203. These co-inoculations were carried out under mixed (simultaneous inoculation, and sequential conditions (non-Saccharomyces yeasts inoculated at initial time and S. cerevisiae at 48, 96 and 144 h. Lower fermentative efficiencies were registered when BHu9 and BSb55 remained pure more time. Conversely, the conversion efficiency was reduced in co-inocula of BCm71/BSc203, when both yeasts interact more time. Metabolites produced during all vinification processes were within acceptable concentration ranges according to the current legislations. Conclusion Time interaction during fermentation processes of non-Saccharomyces and Saccharomyces yeasts showed influence on ethanol production, and this effect would be dependent on the co-inoculated species.

  19. Population heterogeneity in Saccharomyces cerevisiae and Escherichia coli lab scale cultivations simulating industrial scale bioprocesses

    DEFF Research Database (Denmark)

    Heins, Anna-Lena

    Today it is well known that a population of cells in a bioreactor is heterogeneous, opposite to traditional belief, and thus exhibiting distributions of single cell properties e.g. cell size, viability and metabolic activity rather than having a set of characteristics that can be described...

  20. Content of endogenous thiols and radioresistance of gemmating cells of Saccharomyces ellipsoideus and Saccharomyces cerevisiale yeasts

    International Nuclear Information System (INIS)

    Simonyan, N.V.; Avakyan, Ts.M.; Dzhanpoladyan, N.L.; Stepanyan, L.G.

    1983-01-01

    It has been shown that gemmating cells of ''wild type'' yeasts are more radioresistant and contain more endogenous thiols, than resting cells. Gemmating cells of Saccharomyces cerevisial yeasts, carrying the mutation rad 51, as to radioresistance and content of SH groups do not differ from resting cells. The results obtained testify to a connec-- tion between increased radioresistance of the yeast gemmating cells and increased content of endogenous thiols in them

  1. Gains and Losses of Transcription Factor Binding Sites in Saccharomyces cerevisiae and Saccharomyces paradoxus.

    Science.gov (United States)

    Schaefke, Bernhard; Wang, Tzi-Yuan; Wang, Chuen-Yi; Li, Wen-Hsiung

    2015-07-27

    Gene expression evolution occurs through changes in cis- or trans-regulatory elements or both. Interactions between transcription factors (TFs) and their binding sites (TFBSs) constitute one of the most important points where these two regulatory components intersect. In this study, we investigated the evolution of TFBSs in the promoter regions of different Saccharomyces strains and species. We divided the promoter of a gene into the proximal region and the distal region, which are defined, respectively, as the 200-bp region upstream of the transcription starting site and as the 200-bp region upstream of the proximal region. We found that the predicted TFBSs in the proximal promoter regions tend to be evolutionarily more conserved than those in the distal promoter regions. Additionally, Saccharomyces cerevisiae strains used in the fermentation of alcoholic drinks have experienced more TFBS losses than gains compared with strains from other environments (wild strains, laboratory strains, and clinical strains). We also showed that differences in TFBSs correlate with the cis component of gene expression evolution between species (comparing S. cerevisiae and its sister species Saccharomyces paradoxus) and within species (comparing two closely related S. cerevisiae strains). © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  2. Tolerance to winemaking stress conditions of Patagonian strains of Saccharomyces eubayanus and Saccharomyces uvarum.

    Science.gov (United States)

    Origone, A C; Del Mónaco, S M; Ávila, J R; González Flores, M; Rodríguez, M E; Lopes, C A

    2017-08-01

    Evaluating the winemaking stress tolerance of a set of both Saccharomyces eubayanus and Saccharomyces uvarum strains from diverse Patagonian habitats. Yeast strains growth was analysed under increasing ethanol concentrations; all of them were able to grow until 8% v/v ethanol. The effect of different temperature and pH conditions as well as at SO 2 and hexose concentrations was evaluated by means of a central composite experimental design. Only two S. uvarum strains (NPCC 1289 and 1321) were able to grow in most stress conditions. Kinetic parameters analysed (μ max and λ) were statistically affected by temperature, pH and SO 2 , but not influenced by sugar concentration. The obtained growth model was used for predicting optimal growth conditions for both strains: 20°C, 0% w/v SO 2 and pH 4·5. Strains from human-associated environments (chichas) presented the highest diversity in the response to different stress factors. Two S. uvarum strains from chichas demonstrated to be the most tolerant to winemaking conditions. This work evidenced the potential use of two S. uvarum yeast strains as starter cultures in wines fermented at low temperatures. Saccharomyces eubayanus was significantly affected by winemaking stress conditions, limiting its use in this industry. © 2017 The Society for Applied Microbiology.

  3. Gains and Losses of Transcription Factor Binding Sites in Saccharomyces cerevisiae and Saccharomyces paradoxus

    Science.gov (United States)

    Schaefke, Bernhard; Wang, Tzi-Yuan; Wang, Chuen-Yi; Li, Wen-Hsiung

    2015-01-01

    Gene expression evolution occurs through changes in cis- or trans-regulatory elements or both. Interactions between transcription factors (TFs) and their binding sites (TFBSs) constitute one of the most important points where these two regulatory components intersect. In this study, we investigated the evolution of TFBSs in the promoter regions of different Saccharomyces strains and species. We divided the promoter of a gene into the proximal region and the distal region, which are defined, respectively, as the 200-bp region upstream of the transcription starting site and as the 200-bp region upstream of the proximal region. We found that the predicted TFBSs in the proximal promoter regions tend to be evolutionarily more conserved than those in the distal promoter regions. Additionally, Saccharomyces cerevisiae strains used in the fermentation of alcoholic drinks have experienced more TFBS losses than gains compared with strains from other environments (wild strains, laboratory strains, and clinical strains). We also showed that differences in TFBSs correlate with the cis component of gene expression evolution between species (comparing S. cerevisiae and its sister species Saccharomyces paradoxus) and within species (comparing two closely related S. cerevisiae strains). PMID:26220934

  4. Review of Saccharomyces boulardii as a treatment option in IBD

    DEFF Research Database (Denmark)

    Sivananthan, Kavitha; Petersen, Andreas Munk

    2018-01-01

    CONTEXT: Review of the yeast Saccharomyces boulardii as a treatment option for the inflammatory bowel diseases (IBD) ulcerative colitis and Crohn's disease. OBJECTIVE: IBD is caused by an inappropriate immune response to gut microbiota. Treatment options could therefore be prebiotics, probiotics......, antibiotics and/or fecal transplant. In this review, we have looked at the evidence for the yeast S. boulardii as a treatment option. MATERIAL AND METHODS: Searches in PubMed and the Cochrane Library with the MeSH words 'Saccharomyces boulardii AND IBD', 'Saccharomyces boulardii AND Inflammatory Bowel Disease....... Saccharomyces boulardii is, however, a plausible treatment option in the future, but more placebo-controlled clinical studies on both patients with ulcerative colitis and Crohn's disease are needed....

  5. Organization of Replication of Ribosomal DNA in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Linskens, Maarten H.K.; Huberman, Joel A.

    1988-01-01

    Using recently developed replicon mapping techniques, we have analyzed the replication of the ribosomal DNA in Saccharomyces cerevisiae. The results show that (i) the functional origin of replication colocalizes with an autonomously replicating sequence element previously mapped to the

  6. Genome-scale reconstruction of the Saccharomyces cerevisiae metabolic network

    DEFF Research Database (Denmark)

    Förster, Jochen; Famili, I.; Fu, P.

    2003-01-01

    The metabolic network in the yeast Saccharomyces cerevisiae was reconstructed using currently available genomic, biochemical, and physiological information. The metabolic reactions were compartmentalized between the cytosol and the mitochondria, and transport steps between the compartments...

  7. Adaption of Saccharomyces cerevisiae expressing a heterologous protein

    DEFF Research Database (Denmark)

    Krogh, Astrid Mørkeberg; Beck, Vibe; Højlund Christensen, Lars

    2008-01-01

    Production of the heterologous protein, bovine aprotinin, in Saccharomyces cerevisiae was shown to affect the metabolism of the host cell to various extent depending on the strain genotype. Strains with different genotypes, industrial and laboroatory, respectively, were investigated. The maximal...

  8. Effect of Saccharomyces cerevisiae fermentation on the colorants of ...

    African Journals Online (AJOL)

    Effect of Saccharomyces cerevisiae fermentation on the colorants of heated red beetroot extracts. Hayet Ben Haj Koubaier, Ismahen Essaidi, Ahmed Snoussi, Slim Zgoulli, Mohamed Moncef Chaabouni, Phillipe Thonart, Nabiha Bouzouita ...

  9. Progress in terpene synthesis strategies through engineering of Saccharomyces cerevisiae.

    Science.gov (United States)

    Paramasivan, Kalaivani; Mutturi, Sarma

    2017-12-01

    Terpenes are natural products with a remarkable diversity in their chemical structures and they hold a significant market share commercially owing to their distinct applications. These potential molecules are usually derived from terrestrial plants, marine and microbial sources. In vitro production of terpenes using plant tissue culture and plant metabolic engineering, although receiving some success, the complexity in downstream processing because of the interference of phenolics and product commercialization due to regulations that are significant concerns. Industrial workhorses' viz., Escherichia coli and Saccharomyces cerevisiae have become microorganisms to produce non-native terpenes in order to address critical issues such as demand-supply imbalance, sustainability and commercial viability. S. cerevisiae enjoys several advantages for synthesizing non-native terpenes with the most significant being the compatibility for expressing cytochrome P450 enzymes from plant origin. Moreover, achievement of high titers such as 40 g/l of amorphadiene, a sesquiterpene, boosts commercial interest and encourages the researchers to envisage both molecular and process strategies for developing yeast cell factories to produce these compounds. This review contains a brief consideration of existing strategies to engineer S. cerevisiae toward the synthesis of terpene molecules. Some of the common targets for synthesis of terpenes in S. cerevisiae are as follows: overexpression of tHMG1, ERG20, upc2-1 in case of all classes of terpenes; repression of ERG9 by replacement of the native promoter with a repressive methionine promoter in case of mono-, di- and sesquiterpenes; overexpression of BTS1 in case of di- and tetraterpenes. Site-directed mutagenesis such as Upc2p (G888A) in case of all classes of terpenes, ERG20p (K197G) in case of monoterpenes, HMG2p (K6R) in case of mono-, di- and sesquiterpenes could be some generic targets. Efforts are made to consolidate various studies

  10. Redox balancing in recombinant strains of Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Anderlund, M

    1998-09-01

    In metabolically engineered Saccharomyces cerevisiae expressing Pichia stipitis XYL1 and XYL2 genes, encoding xylose reductase (XR) and xylitol dehydrogenase (XDH), respectively, xylitol is excreted as the major product during anaerobic xylose fermentation and only low yields of ethanol are produced. This has been interpreted as a result of the dual cofactor dependence of XR and the exclusive use of NAD{sup +} by XDH. The excretion of xylitol was completely stopped and the formation of glycerol and acetic acid were reduced in xylose utilising S. cerevisiae strains cultivated in oxygen-limited conditions by expressing lower levels of XR than of XDH. The expression level of XYL1 and XYL2 were controlled by changing the promoters and transcription directions of the genes. A new functional metabolic pathway was established when Thermus thermophilus xylA gene was expressed in S. cerevisiae. The recombinant strain was able to ferment xylose to ethanol when cultivated on a minimal medium containing xylose as only carbon source. In order to create a channeled metabolic transfer in the two first steps of the xylose metabolism, XYL1 and XYL2 were fused in-frame and expressed in S. cerevisiae. When the fusion protein, containing a linker of three amino acids, was co expressed together with native XR and XDH monomers, enzyme complexes consisting of chimeric and native subunits were formed. The total activity of these complexes exhibited 10 and 9 times higher XR and XDH activity, respectively, than the original conjugates, consisting of only chimeric subunits. This strain produced less xylitol and the xylitol yield was lower than with strains only expressing native XR and XDH monomers. In addition, more ethanol and less acetic acid were formed. A new gene encoding the cytoplasmic transhydrogenase from Azotobacter vinelandii was cloned. The enzyme showed high similarity to the family of pyridine nucleotide-disulphide oxidoreductase. To analyse the physiological effect of

  11. Sporulation in the Budding Yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Neiman, Aaron M.

    2011-01-01

    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

  12. Molecular Basis for Saccharomyces cerevisiae Biofilm Development

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz

    In this study, I sought to identify genes regulating the global molecular program for development of sessile multicellular communities, also known as biofilm, of the eukaryotic microorganism, Saccharomyces cerevisiae (yeast). Yeast biofilm has a clinical interest, as biofilms can cause chronic...... infections in humans. Biofilm is also interesting from an evolutionary standpoint, as an example of primitive multicellularity. By using a genome-wide screen of yeast deletion mutants, I show that 71 genes are essential for biofilm formation. Two-thirds of these genes are required for transcription of FLO11......, but only a small subset is previously described as regulators of FLO11. These results reveal that the regulation of biofilm formation and FLO11 is even more complex than what has previously been described. I find that the molecular program for biofilm formation shares many essential components with two...

  13. [Urinary infection by Saccharomyces cerevisiae: Emerging yeast?].

    Science.gov (United States)

    Elkhihal, B; Elhalimi, M; Ghfir, B; Mostachi, A; Lyagoubi, M; Aoufi, S

    2015-12-01

    Saccharomyces cerevisiae is a commensal yeast of the digestive, respiratory and genito-urinary tract. It is widely used as a probiotic for the treatment of post-antibiotic diarrhea. It most often occurs in immunocompromised patients frequently causing fungemia. We report the case of an adult diabetic patient who had a urinary tract infection due to S. cerevisiae. The disease started with urination associated with urinary frequency burns without fever. The diagnosis was established by the presence of yeasts on direct examination and positivity of culture on Sabouraud-chloramphenicol three times. The auxanogramme gallery (Auxacolor BioRad(®)) allowed the identification of S. cerevisiae. The patient was put on fluconazole with good outcome. This observation points out that this is an opportunistic yeast in immunocompromised patients. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Social wasps are a Saccharomyces mating nest.

    Science.gov (United States)

    Stefanini, Irene; Dapporto, Leonardo; Berná, Luisa; Polsinelli, Mario; Turillazzi, Stefano; Cavalieri, Duccio

    2016-02-23

    The reproductive ecology of Saccharomyces cerevisiae is still largely unknown. Recent evidence of interspecific hybridization, high levels of strain heterozygosity, and prion transmission suggest that outbreeding occurs frequently in yeasts. Nevertheless, the place where yeasts mate and recombine in the wild has not been identified. We found that the intestine of social wasps hosts highly outbred S. cerevisiae strains as well as a rare S. cerevisiae×S. paradoxus hybrid. We show that the intestine of Polistes dominula social wasps favors the mating of S. cerevisiae strains among themselves and with S. paradoxus cells by providing a succession of environmental conditions prompting cell sporulation and spores germination. In addition, we prove that heterospecific mating is the only option for European S. paradoxus strains to survive in the gut. Taken together, these findings unveil the best hidden secret of yeast ecology, introducing the insect gut as an environmental alcove in which crosses occur, maintaining and generating the diversity of the ascomycetes.

  15. Modification of mutation frequency in Saccharomyces Cerevisiae

    International Nuclear Information System (INIS)

    Vashishat, R.K.; Kakar, S.N.

    1976-01-01

    In a reverse mutation system, using haploid, histidine-requirinq strain of Saccharomyces cerevisiae, the frequency of uv-induced prototrophs increased if the post-irradiation minimal medium was supplemented with limited amounts of histidine. Addition of natural amino acids or RNA bases in the post-irradiation minimal medium, with or without histidine, also increased the uv-induced mutation frequency. Thus, post-irradiation conditions favouring protein and RNA synthesis, are effective in increasing uv-induced mutations in yeast. As compared to uv light, nitrous acid was more effective in inducing reversions in this strain and the frequency increased if the treated cells were plated on minimal medium supplemented with limited amounts of histidine. However, the addition of amino acids or RNA bases decreased the number of revertants. An additional inclusion of histidine reversed the suppressive effect of these metabolites. The mutation induction processes are thus different or differently modifiable in uv and nitrous acid. (author)

  16. Probiotic Properties of Non-Saccharomyces Yeasts

    DEFF Research Database (Denmark)

    Smith, Ida Mosbech

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

  17. Beneficial properties of probiotic yeast Saccharomyces boulardii

    Directory of Open Access Journals (Sweden)

    Tomičić Zorica M.

    2016-01-01

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

  18. Study on biosorption of uranium by alginate immobilized saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Wang Baoe; Xu Weichang; Xie Shuibo; Guo Yangbin

    2005-01-01

    Saccharomyces cerevisiae has great capability of biosorption of uranium. The maxium uptake is 172.4 mg/g according to this study. To adapt to the application of the biomass in the field, the biosorption of uranium by cross-linked and alginate calcium immobilized Saccharomyces cerevisiae is studied. Results indicate the maxium uptake is 185.2 mg/g by formaldehyde cross-linked biomass, and it is 769.2 mg/g by alginate calcium immobilized biomass. (authors)

  19. Saccharomyces cerevisiae var. boulardii fungemia following probiotic treatment

    OpenAIRE

    Appel-da-Silva, Marcelo C.; Narvaez, Gabriel A.; Perez, Leandro R.R.; Drehmer, Laura; Lewgoy, Jairo

    2017-01-01

    Probiotics are commonly prescribed as an adjuvant in the treatment of antibiotic-associated diarrhea caused by Clostridium difficile. We report the case of an immunocompromised 73-year-old patient on chemotherapy who developed Saccharomyces cerevisiae var. boulardii fungemia in a central venous catheter during treatment of antibiotic-associated pseudomembranous colitis with the probiotic Saccharomyces cerevisiae var. boulardii. Fungemia was resolved after interruption of probiotic administrat...

  20. Experience with Saccharomyces boulardii Probiotic in Oncohaematological Patients.

    Science.gov (United States)

    Sulik-Tyszka, Beata; Snarski, Emilian; Niedźwiedzka, Magda; Augustyniak, Małgorzata; Myhre, Thorvald Nilsen; Kacprzyk, Anna; Swoboda-Kopeć, Ewa; Roszkowska, Marta; Dwilewicz-Trojaczek, Jadwiga; Jędrzejczak, Wiesław Wiktor; Wróblewska, Marta

    2018-06-01

    Very few reports have been published to date on the bloodstream infections caused by Saccharomyces spp. in oncohaematological patients, and there are no guidelines on the use of this probiotic microorganism in this population. We describe the use of probiotic preparation containing Saccharomyces boulardii in a large group of oncohaematological patients. We retrospectively analysed the data from 32,000 patient hospitalisations at the haematological centre during 2011-2013 (including 196 haematopoietic stem cell transplant recipients) in a tertiary care university-affiliated hospital. During the study period, 2270 doses of Saccharomyces boulardii probiotic were administered to the oncohaematological patients. In total, 2816 mycological cultures were performed, out of which 772 (27.4%) were positive, with 52 indicating digestive tract colonisation by Saccharomyces spp., mainly in patients with acute myeloid leukaemia (AML), myelodysplastic syndrome (MDS) or multiple myeloma (MM). While colonised, they were hospitalised for 1683 days and 416 microbiological cultures of their clinical samples were performed. In the studied group of patients, there were six blood cultures positive for fungi; however, they comprised Candida species: two C. glabrata, one C. albicans, one C. krusei, one C. tropicalis and one C. parapsilosis. There was no blood culture positive for Saccharomyces spp. Our study indicates that despite colonisation of many oncohaematological patients with Saccharomyces spp., there were no cases of fungal sepsis caused by this species.

  1. Review of Saccharomyces boulardii as a treatment option in IBD.

    Science.gov (United States)

    Sivananthan, Kavitha; Petersen, Andreas Munk

    2018-05-17

    Review of the yeast Saccharomyces boulardii as a treatment option for the inflammatory bowel diseases (IBD) ulcerative colitis and Crohn's disease. IBD is caused by an inappropriate immune response to gut microbiota. Treatment options could therefore be prebiotics, probiotics, antibiotics and/or fecal transplant. In this review, we have looked at the evidence for the yeast S. boulardii as a treatment option. Searches in PubMed and the Cochrane Library with the MeSH words 'Saccharomyces boulardii AND IBD', 'Saccharomyces boulardii AND Inflammatory Bowel Disease', 'Saccharomyces boulardii AND ulcerative colitis' and 'Saccharomyces boulardii AND Crohn's disease' gave total a total of 80 articles. After exclusions because of irrelevance, articles in other languages and some articles that were not available, 16 articles were included in this review. Three of the clinical trials showed a positive effect of S. boulardii in IBD patients (two Crohn's disease, one ulcerative colitis), while there was one trial that didn't prove any effect (Crohn's disease). Included Animal trials and cell assays describes different anti-inflammatory mechanisms of S. boulardii supporting a possible effect when treating IBD patients. The number of studies of S. boulardii as treatment for IBD is limited. Furthermore, the existing trials have small populations and short duration. We do not have enough evidence to prove the effect of S. boulardii in IBD. Saccharomyces boulardii is, however, a plausible treatment option in the future, but more placebo-controlled clinical studies on both patients with ulcerative colitis and Crohn's disease are needed.

  2. An interlaboratory comparison of the performance of ethanol-producing micro-organisms in a xylose-rich acid hydrolysate

    Energy Technology Data Exchange (ETDEWEB)

    Hahn-Haegerdal, B. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Jeppsson, H. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Olsson, L. (Dept. of Applied Microbiology, Lund Inst. of Technology/Univ. of Lund (Sweden)); Mohagheghi, A. (Bioprocess and Fuels Engineering Research Branch, National Renewable Energy Lab., Golden, CO (United States))

    1994-03-01

    A xylose-rich, dilute-acid-pretreated corn-cob hydrolysate was fermented by Escherichia coli ATCC 11303, recombinant (rec) E. coli B (pLOI 297 and KO11), Pichia stipitis (CBS 5773, 6054 and R), Saccharomyces cerevisiae isolate 3 in combination with xylose isomerase, rec S. cerevisiae (TJ1, H550 and H477) and Fusarium oxysporum VTT-D-80134 in an interlaboratory comparison. The micro-organisms were studied according to three different options: (A) fermentation under consistent conditions. (B) fermentation under optimal conditions for the organism, and (C) fermentation under optimal conditions for the organism with detoxification of the hydrolysate. The highest yields of ethanol, 0.24 g/g (A), 0.36 g/g (B) and 0.54 g/g (C), were obtained from rec E. coli B, KO11. P. stipitis and F. oxysporum were sensitive to the inhibitors present in the hydrolysate and produced a maximum yield of 0.34 g/g (C) and 0.04 g/g (B), respectively. The analysis of the corn-cob hydrolysate and aspects of process economy of the different fermentation options (pH, sterilization, nutrient supplementation, adaptation, detoxification) are discussed. (orig.)

  3. Construction of a novel kind of expression plasmid by homologous recombination in Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xiangling

    2005-01-01

    [1]Brunelli, J. P., Pall, M. L., A series of yeast vectors for expression of cDNAs and other DNA sequences, Yeast, 1993, 9: 1299―1308.[2]Sikorski, R. S., Hieter, P., A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae, Genetics, 1989, 122: 19―27.[3]Bonneaud, N., Ozier-Kalogerogoulos, O., Li, G. et al., A family of low and high copy replicative, integrative and single-stranded S. cerevisiae /E. coli shuttle vector, Yeast, 1991, 7: 609―615.[4]Huo, K. K., Yu, L. L., Chen, X. J., Li, Y. Y., A stable vector for high-level expression and secretion of human interferon alpha A in yeast, Science in China, Ser. B, 1993, 36(5): 557―567.[5]Zhou, Z. X., Yuan, H. Y., He, W. et al., Expression of the modified HBsAg gene SA-28 directed by a constitutive promoter, Journal of Fudan university (Natural Science), 2000, 39(3): 264―268.[6]Paques, F., Haber, J. E., Multiple pathways of recombination induces by double-strand breaks in Saccharomyces cerevisiae, Microbiology and Molecular Biology Reviews, 1999, 63(2): 349―404.[7]Martin, K., Damage-induced recombination in the yeast Saccharomyces cerevisiae, Mutation Research, 2000, 451: 91―105.[8]Alira, S., Tomoko, O., Homologous recombination and the roles of double-strand breaks, TIBS, 1995, 20: 387―391.[9]Patrick, S., Kelly, M. T., Stephen, V. K., Recombination factor of Saccharomyces cerevisiae, Mutation Research, 2000, 451: 257―275.[10]Manivasakam, P., Weber, S. C., McElver, J., Schiestl, R. H., Micro-homology mediated PCR targeting in Saccharomyces cerevisiae, Nucleic Acids Res., 1995, 23(14): 2799―2800.[11]Baudin, A., Lacroute, F., Cullin, C., A simple and efficient method for direct gene deletion in Saccharomyces cerevisiae, Nucleic Acids Res., 1993, 21(14): 3329―3330.[12]Hua, S. B., Qiu, M., Chan, E., Zhu, L., Luo, Y., Minimum length of sequence homology required for in vivo cloning by homolo-gous recombination in yeast, Plasmid, 1997, 38

  4. Ethanol Production by Soy Fiber Treatment and Simultaneous Saccharification and Co-Fermentation in an Integrated Corn-Soy Biorefinery

    Directory of Open Access Journals (Sweden)

    Jasreen K. Sekhon

    2018-05-01

    Full Text Available Insoluble fiber (IF recovered from the enzyme-assisted aqueous extraction process (EAEP of soybeans is a fraction rich in carbohydrates and proteins. It can be used to enhance ethanol production in an integrated corn-soy biorefinery, which combines EAEP with traditional corn-based ethanol processing. The present study evaluated IF as a substrate for ethanol production. The effects of treatment of IF (soaking in aqueous ammonia (SAA, liquid hot water (LHW, and enzymatic hydrolysis, primarily simultaneous saccharification and co-fermentation (SSCF, as well as scaling up (250 mL to 60 L on ethanol production from IF alone or a corn and IF slurry were investigated. Enzymatic hydrolysis (pectinase, cellulase, and xylanase, each added at 5% soy solids during simultaneous saccharification and fermentation/SSCF was the best treatment to maximize ethanol production from IF. Ethanol yield almost doubled when SSCF of IF was performed with Saccharomyces cerevisiae and Escherichia coli KO11. Addition of IF in dry-grind corn fermentation increased the ethanol production rate (~31%, but low ethanol tolerance of E. coli KO11 was a limiting factor for employing SSCF in combination corn and IF fermentation. Nonlinear Monod modeling accurately predicted the effect of ethanol concentration on E. coli KO11 growth kinetics by Hanes-Woolf linearization. Collectively, the results from this study suggest a potential of IF as a substrate, alone or in dry-grind corn fermentation, where it enhances the ethanol production rate. IF can be incorporated in the current bioethanol industry with no added capital investment, except enzymes.

  5. Identification of mitochondrial carriers in Saccharomyces cerevisiae by transport assay of reconstituted recombinant proteins.

    Science.gov (United States)

    Palmieri, Ferdinando; Agrimi, Gennaro; Blanco, Emanuela; Castegna, Alessandra; Di Noia, Maria A; Iacobazzi, Vito; Lasorsa, Francesco M; Marobbio, Carlo M T; Palmieri, Luigi; Scarcia, Pasquale; Todisco, Simona; Vozza, Angelo; Walker, John

    2006-01-01

    The inner membranes of mitochondria contain a family of carrier proteins that are responsible for the transport in and out of the mitochondrial matrix of substrates, products, co-factors and biosynthetic precursors that are essential for the function and activities of the organelle. This family of proteins is characterized by containing three tandem homologous sequence repeats of approximately 100 amino acids, each folded into two transmembrane alpha-helices linked by an extensive polar loop. Each repeat contains a characteristic conserved sequence. These features have been used to determine the extent of the family in genome sequences. The genome of Saccharomyces cerevisiae contains 34 members of the family. The identity of five of them was known before the determination of the genome sequence, but the functions of the remaining family members were not. This review describes how the functions of 15 of these previously unknown transport proteins have been determined by a strategy that consists of expressing the genes in Escherichia coli or Saccharomyces cerevisiae, reconstituting the gene products into liposomes and establishing their functions by transport assay. Genetic and biochemical evidence as well as phylogenetic considerations have guided the choice of substrates that were tested in the transport assays. The physiological roles of these carriers have been verified by genetic experiments. Various pieces of evidence point to the functions of six additional members of the family, but these proposals await confirmation by transport assay. The sequences of many of the newly identified yeast carriers have been used to characterize orthologs in other species, and in man five diseases are presently known to be caused by defects in specific mitochondrial carrier genes. The roles of eight yeast mitochondrial carriers remain to be established.

  6. Saccharomyces cerevisiae GTPase complex: Gtr1p-Gtr2p regulates cell-proliferation through Saccharomyces cerevisiae Ran-binding protein, Yrb2p

    International Nuclear Information System (INIS)

    Wang Yonggang; Nakashima, Nobutaka; Sekiguchi, Takeshi; Nishimoto, Takeharu

    2005-01-01

    A Gtr1p GTPase, the GDP mutant of which suppresses both temperature-sensitive mutants of Saccharomyces cerevisiae RanGEF/Prp20p and RanGAP/Rna1p, was presently found to interact with Yrb2p, the S. cerevisiae homologue of mammalian Ran-binding protein 3. Gtr1p bound the Ran-binding domain of Yrb2p. In contrast, Gtr2p, a partner of Gtr1p, did not bind Yrb2p, although it bound Gtr1p. A triple mutant: yrb2Δ gtr1Δ gtr2Δ was lethal, while a double mutant: gtr1Δ gtr2Δ survived well, indicating that Yrb2p protected cells from the killing effect of gtr1Δ gtr2Δ. Recombinant Gtr1p and Gtr2p were purified as a complex from Escherichia coli. The resulting Gtr1p-Gtr2p complex was comprised of an equal amount of Gtr1p and Gtr2p, which inhibited the Rna1p/Yrb2 dependent RanGAP activity. Thus, the Gtr1p-Gtr2p cycle was suggested to regulate the Ran cycle through Yrb2p

  7. ANIMAL ENTEROTOXIGENIC ESCHERICHIA COLI

    Science.gov (United States)

    Dubreuil, J. Daniel; Isaacson, Richard E.; Schifferli, Dieter M.

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors; adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17 and F18 fimbriae. Once established in the animal small intestine, ETEC produces enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes; heat-labile toxin that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This chapter describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics and the identification of potential new targets identified by genomics are presented in the context of animal ETEC. PMID:27735786

  8. iTRAQ-based proteome profiling of Saccharomyces cerevisiae and cryotolerant species Saccharomyces uvarum and Saccharomyces kudriavzevii during low-temperature wine fermentation.

    Science.gov (United States)

    García-Ríos, Estéfani; Querol, Amparo; Guillamón, José Manuel

    2016-09-02

    Temperature is one of the most important parameters to affect the duration and rate of alcoholic fermentation and final wine quality. Some species of the Saccharomyces genus have shown better adaptation at low temperature than Saccharomyces cerevisiae, which was the case of cryotolerant yeasts Saccharomyces uvarum and Saccharomyces kudriavzevii. In an attempt to detect inter-specific metabolic differences, we characterized the proteomic landscape of these cryotolerant species grown at 12°C and 28°C, which we compared with the proteome of S. cerevisiae (poorly adapted at low temperature). Our results showed that the main differences among the proteomic profiling of the three Saccharomyces strains grown at 12°C and 28°C lay in translation, glycolysis and amino acid metabolism. Our data corroborate previous transcriptomic results, which suggest that S. kudriavzevii is better adapted to grow at low temperature as a result of enhanced more efficient translation. Fitter amino acid biosynthetic pathways can also be mechanisms that better explain biomass yield in cryotolerant strains. Yet even at low temperature, S. cerevisiae is the most fermentative competitive species. A higher concentration of glycolytic and alcoholic fermentation enzymes in the S. cerevisiae strain might explain such greater fermentation activity. Temperature is one of the main relevant environmental variables that microorganisms have to cope with and it is also a key factor in some industrial processes that involve microorganisms. However, we are still far from understanding the molecular and physiological mechanisms of adaptation at low temperatures. The results obtained in this study provided a global atlas of the proteome changes triggered by temperature in three different species of the genus Saccharomyces with different degree of cryotolerance. These results would facilitate a better understanding of mechanisms for how yeast could adapt at the low temperature of growth. Copyright © 2016

  9. Lycopene overproduction in Saccharomyces cerevisiae through combining pathway engineering with host engineering.

    Science.gov (United States)

    Chen, Yan; Xiao, Wenhai; Wang, Ying; Liu, Hong; Li, Xia; Yuan, Yingjin

    2016-06-21

    Microbial production of lycopene, a commercially and medically important compound, has received increasing concern in recent years. Saccharomyces cerevisiae is regarded as a safer host for lycopene production than Escherichia coli. However, to date, the lycopene yield (mg/g DCW) in S. cerevisiae was lower than that in E. coli and did not facilitate downstream extraction process, which might be attributed to the incompatibility between host cell and heterologous pathway. Therefore, to achieve lycopene overproduction in S. cerevisiae, both host cell and heterologous pathway should be delicately engineered. In this study, lycopene biosynthesis pathway was constructed by integration of CrtE, CrtB and CrtI in S. cerevisiae CEN.PK2. When YPL062W, a distant genetic locus, was deleted, little acetate was accumulated and approximately 100 % increase in cytosolic acetyl-CoA pool was achieved relative to that in parental strain. Through screening CrtE, CrtB and CrtI from diverse species, an optimal carotenogenic enzyme combination was obtained, and CrtI from Blakeslea trispora (BtCrtI) was found to have excellent performance on lycopene production as well as lycopene proportion in carotenoid. Then, the expression level of BtCrtI was fine-tuned and the effect of cell mating types was also evaluated. Finally, potential distant genetic targets (YJL064W, ROX1, and DOS2) were deleted and a stress-responsive transcription factor INO2 was also up-regulated. Through the above modifications between host cell and carotenogenic pathway, lycopene yield was increased by approximately 22-fold (from 2.43 to 54.63 mg/g DCW). Eventually, in fed-batch fermentation, lycopene production reached 55.56 mg/g DCW, which is the highest reported yield in yeasts. Saccharomyces cerevisiae was engineered to produce lycopene in this study. Through combining host engineering (distant genetic loci and cell mating types) with pathway engineering (enzyme screening and gene fine-tuning), lycopene yield was

  10. Impact of oxygenation on the performance of three non-Saccharomyces yeasts in co-fermentation with Saccharomyces cerevisiae.

    Science.gov (United States)

    Shekhawat, Kirti; Bauer, Florian F; Setati, Mathabatha E

    2017-03-01

    The sequential or co-inoculation of grape must with non-Saccharomyces yeast species and Saccharomyces cerevisiae wine yeast strains has recently become a common practice in winemaking. The procedure intends to enhance unique aroma and flavor profiles of wine. The extent of the impact of non-Saccharomyces strains depends on their ability to produce biomass and to remain metabolically active for a sufficiently long period. However, mixed-culture wine fermentations tend to become rapidly dominated by S. cerevisiae, reducing or eliminating the non-Saccharomyces yeast contribution. For an efficient application of these yeasts, it is therefore essential to understand the environmental factors that modulate the population dynamics of such ecosystems. Several environmental parameters have been shown to influence population dynamics, but their specific effect remains largely uncharacterized. In this study, the population dynamics in co-fermentations of S. cerevisiae and three non-Saccharomyces yeast species: Torulaspora delbrueckii, Lachancea thermotolerans, and Metschnikowia pulcherrima, was investigated as a function of oxygen availability. In all cases, oxygen availability strongly influenced population dynamics, but clear species-dependent differences were observed. Our data show that L. thermotolerans required the least oxygen, followed by T. delbrueckii and M. pulcherrima. Distinct species-specific chemical volatile profiles correlated in all cases with increased persistence of non-Saccharomyces yeasts, in particular increases in some higher alcohols and medium chain fatty acids. The results highlight the role of oxygen in regulating the succession of yeasts during wine fermentations and suggests that more stringent aeration strategies would be necessary to support the persistence of non-Saccharomyces yeasts in real must fermentations.

  11. Distribution patterns of Saccharomyces species in cultural landscapes of Germany.

    Science.gov (United States)

    Brysch-Herzberg, Michael; Seidel, Martin

    2017-08-01

    The distribution patterns of the three Saccharomyces species, Saccharomyces paradoxus, S. uvarum and S. cerevisiae, were investigated by a culture-dependent approach in order to understand better how these species propagate in the cultural landscape of Germany. Saccharomyces paradoxus, the closest relative of S. cerevisiae, is shown to be a true woodland species. It was frequently found in the soil under conifers indicating that S. paradoxus is an autochthonous member of the microbial community in this habitat. Physiological characteristics of the species like the Crabtree effect and high tolerance against ethanol suggest that the species is adapted to regular supply with considerable amounts of sugars. Additionally, a high proportion of the S. paradoxus strains isolated in this study are shown to have the rare ability to ferment melezitose. For these reasons, it is hypothesized that S. paradoxus may be closely associated with the honeydew system in forests. Saccharomyces cerevisiae was rare in most habitats and only exceeded the frequency of S. paradoxus in habitats characterized by modern agricultural mass production of fruit. Both the landscape structure and the agricultural system heavily influence the frequencies of Saccharomyces species. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

    Johnson, Eric A

    2013-01-01

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

  13. Pathways of ultraviolet mutability in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Lemontt, J.F.

    1977-01-01

    Non-allelic mutants of Saccharomyces cerevisiae with reduced capacity for ultraviolet light (UV)-induced forward mutation from CAN1 to can1 were assigned to seven distinct genetic loci, each with allele designations umr1-1, umr2-1, ..., umr7-1 to indicate UV mutation resistance. None conferred a great deal of UV sensitivity. When assayed on yeast extract-peptone-dextrose complex growth agar, umr1, umr3, and umr7 were the most UV-sensitive. When assayed on synthetic agar lacking arginine, however, umr3 was the most UV-sensitive. All strains carrying each of the seven umr genes exhibited varying degrees of defective UV mutability, compact with wild types. Normal UV revertibility of three different alleles was observed in strains carrying either umr4, umr5, umr6, or umr7. Five a/α homozygous umr diploids failed to sporulate. One of these, umr7, blocked normal secretion of alpha hormone in α segregants and could not conjugate with a strains. The phenotypes of umr mutants are consistent with the existence of branched UV mutation pathways of different specificity

  14. Microsatellite analysis of Saccharomyces uvarum diversity.

    Science.gov (United States)

    Masneuf-Pomarede, Isabelle; Salin, Franck; Börlin, Marine; Coton, Emmanuel; Coton, Monika; Jeune, Christine Le; Legras, Jean-Luc

    2016-03-01

    Considered as a sister species of Saccharomyces cerevisiae, S. uvarum is, to a lesser extent, an interesting species for fundamental and applied research studies. Despite its potential interest as a new gene pool for fermenting agents, the intraspecific molecular genetic diversity of this species is still poorly investigated. In this study, we report the use of nine microsatellite markers to describe S. uvarum genetic diversity and population structure among 108 isolates from various geographical and substrate origins (wine, cider and natural sources). Our combined microsatellite markers set allowed differentiating 89 genotypes. In contrast to S. cerevisiae genetic diversity, wild and human origin isolates were intertwined. A total of 75% of strains were proven to be homozygotes and estimated heterozygosity suggests a selfing rate above 0.95 for the different population tested here. From this point of view, the S. uvarum life cycle appears to be more closely related to S. paradoxus or S. cerevisiae of natural resources than S. cerevisiae wine isolates. Population structure could not be correlated to distinct geographic or technological origins, suggesting lower differentiation that may result from a large exchange between human and natural populations mediated by insects or human activities. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Sugar and Glycerol Transport in Saccharomyces cerevisiae.

    Science.gov (United States)

    Bisson, Linda F; Fan, Qingwen; Walker, Gordon A

    2016-01-01

    In Saccharomyces cerevisiae the process of transport of sugar substrates into the cell comprises a complex network of transporters and interacting regulatory mechanisms. Members of the large family of hexose (HXT) transporters display uptake efficiencies consistent with their environmental expression and play physiological roles in addition to feeding the glycolytic pathway. Multiple glucose-inducing and glucose-independent mechanisms serve to regulate expression of the sugar transporters in yeast assuring that expression levels and transporter activity are coordinated with cellular metabolism and energy needs. The expression of sugar transport activity is modulated by other nutritional and environmental factors that may override glucose-generated signals. Transporter expression and activity is regulated transcriptionally, post-transcriptionally and post-translationally. Recent studies have expanded upon this suite of regulatory mechanisms to include transcriptional expression fine tuning mediated by antisense RNA and prion-based regulation of transcription. Much remains to be learned about cell biology from the continued analysis of this dynamic process of substrate acquisition.

  16. Induction of homologous recombination in Saccharomyces cerevisiae.

    Science.gov (United States)

    Simon, J R; Moore, P D

    1988-09-01

    We have investigated the effects of UV irradiation of Saccharomyces cerevisiae in order to distinguish whether UV-induced recombination results from the induction of enzymes required for homologous recombination, or the production of substrate sites for recombination containing regions of DNA damage. We utilized split-dose experiments to investigate the induction of proteins required for survival, gene conversion, and mutation in a diploid strain of S. cerevisiae. We demonstrate that inducing doses of UV irradiation followed by a 6 h period of incubation render the cells resistant to challenge doses of UV irradiation. The effects of inducing and challenge doses of UV irradiation upon interchromosomal gene conversion and mutation are strictly additive. Using the yeast URA3 gene cloned in non-replicating single- and double-stranded plasmid vectors that integrate into chromosomal genes upon transformation, we show that UV irradiation of haploid yeast cells and homologous plasmid DNA sequences each stimulate homologous recombination approximately two-fold, and that these effects are additive. Non-specific DNA damage has little effect on the stimulation of homologous recombination, as shown by studies in which UV-irradiated heterologous DNA was included in transformation/recombination experiments. We further demonstrate that the effect of competing single- and double-stranded heterologous DNA sequences differs in UV-irradiated and unirradiated cells, suggesting an induction of recombinational machinery in UV-irradiated S. cerevisiae cells.

  17. [Recent advances in Saccharomyces boulardii research].

    Science.gov (United States)

    Im, E; Pothoulakis, C

    2010-09-01

    This review summarizes the probiotic mechanisms of action of Saccharomyces boulardii (S. boulardii) against inflammatory and non-inflammatory diarrheal conditions. S. boulardii is distributed in lyophilized form in many countries and used for the prevention of diarrhea in children and adults, including Clostridium difficile (C. difficile) associated infection. The main mechanisms of action of S. boulardii include inhibition of activities of bacterial pathogenic products, trophic effects on the intestinal mucosa, as well as modification of host signaling pathways involved in inflammatory and non-inflammatory intestinal diseases. S. boulardii inhibits production of pro-inflammatory cytokines by inhibiting main regulators of inflammation, including nuclear factor κB (NF-κB), and mitogen-activated protein kinases (MAP kinases), ERK1/2 and p38, but stimulates production of anti-inflammatory molecules such as peroxisome proliferator-activated receptor-gamma (PPAR-γ). Moreover, S. boulardii suppresses bacterial infection by inhibiting adhesion and/or overgrowth of bacteria, produces a serine protease that cleaves C. difficile toxin A, and stimulates antibody production against this toxin. Furthermore, S. boulardii may interfere with pathogenesis of Inflammatory Bowel Disease (IBD) by acting on T cells and acts in diarrheal conditions by improving the fecal biostructure in patients with diarrhea. These diverse mechanisms exerted by S. boulardii provide molecular clues for its effectiveness in diarrheal diseases and intestinal inflammatory conditions with an inflammatory component. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

  18. Response of Saccharomyces cerevisiae to cadmium stress

    International Nuclear Information System (INIS)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C.; Rosa, Carlos Augusto

    2009-01-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K + and Na + ) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  19. Response of Saccharomyces cerevisiae to cadmium stress

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Luciana Mara Costa; Ribeiro, Frederico Haddad; Neves, Maria Jose [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Radiobiologia], e-mail: luamatu@uol.com.br; Porto, Barbara Abranches Araujo; Amaral, Angela M.; Menezes, Maria Angela B.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Lab. de Ativacao Neutronica], e-mail: menezes@cdtn.br; Rosa, Carlos Augusto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Microbiologia], e-mail: carlrosa@icb.ufmg

    2009-07-01

    The intensification of industrial activity has been greatly contributing with the increase of heavy metals in the environment. Among these heavy metals, cadmium becomes a serious pervasive environmental pollutant. The cadmium is a heavy metal with no biological function, very toxic and carcinogenic at low concentrations. The toxicity of cadmium and several other metals can be mainly attributed to the multiplicity of coordination complexes and clusters that they can form. Some aspects of the cellular response to cadmium were extensively investigated in the yeast Saccharomyces cerevisiae. The primary site of interaction between many toxic metals and microbial cells is the plasma membrane. Plasma-membrane permeabilisation has been reported in a variety of microorganisms following cadmium exposure, and is considered one mechanism of cadmium toxicity in the yeast. In this work, using the yeast strain S. cerevisiae W303-WT, we have investigated the relationships between Cd uptake and release of cellular metal ions (K{sup +} and Na{sup +}) using neutron activation technique. The neutron activation was an easy, rapid and suitable technique for doing these metal determinations on yeast cells; was observed the change in morphology of the strains during the process of Cd accumulation, these alterations were observed by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) during incorporation of cadmium. (author)

  20. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast...... to uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...

  1. Intracellular Signal Triggered by Cholera Toxin in Saccharomyces boulardii and Saccharomyces cerevisiae

    Science.gov (United States)

    Brandão, Rogelio L.; Castro, Ieso M.; Bambirra, Eduardo A.; Amaral, Sheila C.; Fietto, Luciano G.; Tropia, Maria José M.; Neves, Maria José; Dos Santos, Raquel G.; Gomes, Newton C. M.; Nicoli, Jacques R.

    1998-01-01

    As is the case for Saccharomyces boulardii, Saccharomyces cerevisiae W303 protects Fisher rats against cholera toxin (CT). The addition of glucose or dinitrophenol to cells of S. boulardii grown on a nonfermentable carbon source activated trehalase in a manner similar to that observed for S. cerevisiae. The addition of CT to the same cells also resulted in trehalase activation. Experiments performed separately on the A and B subunits of CT showed that both are necessary for activation. Similarly, the addition of CT but not of its separate subunits led to a cyclic AMP (cAMP) signal in both S. boulardii and S. cerevisiae. These data suggest that trehalase stimulation by CT probably occurred through the cAMP-mediated protein phosphorylation cascade. The requirement of CT subunit B for both the cAMP signal and trehalase activation indicates the presence of a specific receptor on the yeasts able to bind to the toxin, a situation similar to that observed for mammalian cells. This hypothesis was reinforced by experiments with 125I-labeled CT showing specific binding of the toxin to yeast cells. The adhesion of CT to a receptor on the yeast surface through the B subunit and internalization of the A subunit (necessary for the cAMP signal and trehalase activation) could be one more mechanism explaining protection against the toxin observed for rats treated with yeasts. PMID:9464394

  2. Exploring the northern limit of the distribution of Saccharomyces cerevisiae and Saccharomyces paradoxus in North America.

    Science.gov (United States)

    Charron, Guillaume; Leducq, Jean-Baptiste; Bertin, Chloé; Dubé, Alexandre K; Landry, Christian R

    2014-03-01

    We examined the northern limit of Saccharomyces cerevisiae and Saccharomyces paradoxus in northeast America. We collected 876 natural samples at 29 sites and applied enrichment methods for the isolation of mesophilic yeasts. We uncovered a large diversity of yeasts, in some cases, associated with specific substrates. Sequencing of the ITS1, 5.8S and ITS2 loci allowed to assign 226 yeast strains at the species level, including 41 S. paradoxus strains. Our intensive sampling suggests that if present, S. cerevisiae is rare at these northern latitudes. Our sampling efforts spread across several months of the year revealed that successful sampling increases throughout the summer and diminishes significantly at the beginning of the fall. The data obtained on the ecological context of yeasts corroborate what was previously reported on Pichiaceae, Saccharomycodaceae, Debaryomycetaceae and Phaffomycetaceae yeast families. We identified 24 yeast isolates that could not be assigned to any known species and that may be of taxonomic, medical, or biotechnological importance. Our study reports new data on the taxonomic diversity of yeasts and new resources for studying the evolution and ecology of S. paradoxus. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli

    DEFF Research Database (Denmark)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production econo...

  4. Effect of Saccharomyces, Non-Saccharomyces Yeasts and Malolactic Fermentation Strategies on Fermentation Kinetics and Flavor of Shiraz Wines

    Directory of Open Access Journals (Sweden)

    Heinrich du Plessis

    2017-12-01

    Full Text Available The use of non-Saccharomyces yeasts to improve complexity and diversify wine style is increasing; however, the interactions between non-Saccharomyces yeasts and lactic acid bacteria (LAB have not received much attention. This study investigated the interactions of seven non-Saccharomyces yeast strains of the genera Candida, Hanseniaspora, Lachancea, Metschnikowia and Torulaspora in combination with S. cerevisiae and three malolactic fermentation (MLF strategies in a Shiraz winemaking trial. Standard oenological parameters, volatile composition and sensory profiles of wines were investigated. Wines produced with non-Saccharomyces yeasts had lower alcohol and glycerol levels than wines produced with S. cerevisiae only. Malolactic fermentation also completed faster in these wines. Wines produced with non-Saccharomyces yeasts differed chemically and sensorially from wines produced with S. cerevisiae only. The Candida zemplinina and the one L. thermotolerans isolate slightly inhibited LAB growth in wines that underwent simultaneous MLF. Malolactic fermentation strategy had a greater impact on sensory profiles than yeast treatment. Both yeast selection and MLF strategy had a significant effect on berry aroma, but MLF strategy also had a significant effect on acid balance and astringency of wines. Winemakers should apply the optimal yeast combination and MLF strategy to ensure fast completion of MLF and improve wine complexity.

  5. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    The simple eukaryote Saccharomyces cerevisiae has proved to be a useful organism for elucidating the mechanisms that govern cell cycle progression in eukaryotic cells. The excellent in vivo system permits a cell cycle study using temperature sensitive mutants. In addition, it is possible to study...... many genes and gene products from higher eukaryotes in Saccharomyces cerevisiae because many genes and biological processes are homologous or similar in lower and in higher eukaryotes. The highly developed methods of genetics and molecular biology greatly facilitates studies of higher eukaryotic...... processes.Programmmed cell death with apoptosis plays a major role in development and homeostatis in most, if not all, animal cells. Apoptosis is a morphologically distinct form of death, that requires the activation of a highly regulated suicide program. Saccharomyces cerevisiae provides a new system...

  6. Industrial Relevance of Chromosomal Copy Number Variation in Saccharomyces Yeasts

    Science.gov (United States)

    Gorter de Vries, Arthur R.; Pronk, Jack T.

    2017-01-01

    ABSTRACT Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have contributed to an extensive set of methods for analyzing and introducing CCNV. Moreover, these studies provided insight into the balance between negative and positive impacts of CCNV in evolutionary contexts. A growing body of evidence indicates that CCNV not only frequently occurs in industrial strains of Saccharomyces yeasts but also is a key contributor to the diversity of industrially relevant traits. This notion is further supported by the frequent involvement of CCNV in industrially relevant traits acquired during evolutionary engineering. This review describes recent developments in genome sequencing and genome editing techniques and discusses how these offer opportunities to unravel contributions of CCNV in industrial Saccharomyces strains as well as to rationally engineer yeast chromosomal copy numbers and karyotypes. PMID:28341679

  7. Saccharomyces boulardii CNCM I-745 in different clinical conditions.

    Science.gov (United States)

    Dinleyici, Ener Cagri; Kara, Ates; Ozen, Metehan; Vandenplas, Yvan

    2014-11-01

    Saccharomyces boulardii is a well-known probiotic worldwide, and there are numerous studies including experimental and clinical trials in children and adults by the use of S. boulardii. The objective of the present report is to provide an update on the evidence for the efficacy of S. boulardii CNCM I-745 in different clinical conditions. Saccharomyces boulardii is one of the best-studied probiotics in acute gastroenteritis (AGE) and is shown to be safe and to reduce the duration of diarrhea and hospitalization by about 1 day. Saccharomyces boulardii is one of the recommended probiotics for AGE in children by European Society of Paediatric Infectious Diseases and European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN). Saccharomyces boulardii is also a recommended probiotic for the prevention of antibiotic-associated diarrhea (AAD), and a recent study showed promising results for the treatment of AAD in children. There is insufficient evidence to recommend the long-term use of S. boulardii in patients with irritable bowel syndrome. Although some clinical studies showed positive effects of S. boulardii on inflammation, there is no clinical evidence that S. boulardii is useful in inflammatory bowel disease. Saccharomyces boulardii could be used in patients needing Helicobacter pylori eradication because the S. boulardii improves compliance, decreases the side effects and moderately increases the eradication rate. There are new promising results (improving feeding tolerance, shorten the course of hyperbilirubinemia), but we do still not recommend the routine use of S. boulardii in newborns. Saccharomyces boulardii CNCM I-745 is a good example for the statement that each probiotic needs to be taxonomically characterized and its efficacy and safety should be documented individually in different clinical settings.

  8. How did Saccharomyces evolve to become a good brewer?

    Science.gov (United States)

    Piskur, Jure; Rozpedowska, Elzbieta; Polakova, Silvia; Merico, Annamaria; Compagno, Concetta

    2006-04-01

    Brewing and wine production are among the oldest technologies and their products are almost indispensable in our lives. The central biological agents of beer and wine fermentation are yeasts belonging to the genus Saccharomyces, which can accumulate ethanol. Recent advances in comparative genomics and bioinformatics have made it possible to elucidate when and why yeasts produce ethanol in high concentrations, and how this remarkable trait originated and developed during their evolutionary history. Two research groups have shed light on the origin of the genes encoding alcohol dehydrogenase and the process of ethanol accumulation in Saccharomyces cerevisiae.

  9. Production of a heterologous proteinase A by Saccharomyces kluyveri

    DEFF Research Database (Denmark)

    Møller, Kasper; Tidemand, L.D.; Winther, J.R.

    2001-01-01

    In order to evaluate the potential of Saccharomyces kluyveri for heterologous protein production, S. kluyveri Y159 was transformed with a S. cerevisiae-based multi-copy plasmid containing the S. cerevisiae PEP4 gene, which encodes proteinase A, under the control of its native promoter. As a refer......In order to evaluate the potential of Saccharomyces kluyveri for heterologous protein production, S. kluyveri Y159 was transformed with a S. cerevisiae-based multi-copy plasmid containing the S. cerevisiae PEP4 gene, which encodes proteinase A, under the control of its native promoter...

  10. Accumulation of gold using Baker's yeast, Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Roy, Kamalika; Lahiri, Susanta; Sinha, P.

    2006-01-01

    Authors have reported preconcentration of 152 Eu, a long-lived fission product, by yeast cells, Saccharomyces cerevisiae. Gold being a precious metal is used in electroplating, hydrogenation catalyst, etc. Heterogeneous composition of samples and low concentration offers renewed interest in its selective extraction of gold using various extractants. Gold can be recovered from different solutions using various chemical reagents like amines, organophosphorus compounds, and extractants containing sulphur as donor atom, etc. In the present work, two different strains of baker's yeast, Saccharomyces cerevisiae have been used to study the preconcentration of gold at various experimental conditions

  11. Regulation of Cation Balance in Saccharomyces cerevisiae

    Science.gov (United States)

    Cyert, Martha S.; Philpott, Caroline C.

    2013-01-01

    All living organisms require nutrient minerals for growth and have developed mechanisms to acquire, utilize, and store nutrient minerals effectively. In the aqueous cellular environment, these elements exist as charged ions that, together with protons and hydroxide ions, facilitate biochemical reactions and establish the electrochemical gradients across membranes that drive cellular processes such as transport and ATP synthesis. Metal ions serve as essential enzyme cofactors and perform both structural and signaling roles within cells. However, because these ions can also be toxic, cells have developed sophisticated homeostatic mechanisms to regulate their levels and avoid toxicity. Studies in Saccharomyces cerevisiae have characterized many of the gene products and processes responsible for acquiring, utilizing, storing, and regulating levels of these ions. Findings in this model organism have often allowed the corresponding machinery in humans to be identified and have provided insights into diseases that result from defects in ion homeostasis. This review summarizes our current understanding of how cation balance is achieved and modulated in baker’s yeast. Control of intracellular pH is discussed, as well as uptake, storage, and efflux mechanisms for the alkali metal cations, Na+ and K+, the divalent cations, Ca2+ and Mg2+, and the trace metal ions, Fe2+, Zn2+, Cu2+, and Mn2+. Signal transduction pathways that are regulated by pH and Ca2+ are reviewed, as well as the mechanisms that allow cells to maintain appropriate intracellular cation concentrations when challenged by extreme conditions, i.e., either limited availability or toxic levels in the environment. PMID:23463800

  12. Combinatorial Cis-regulation in Saccharomyces Species

    Directory of Open Access Journals (Sweden)

    Aaron T. Spivak

    2016-03-01

    Full Text Available Transcriptional control of gene expression requires interactions between the cis-regulatory elements (CREs controlling gene promoters. We developed a sensitive computational method to identify CRE combinations with conserved spacing that does not require genome alignments. When applied to seven sensu stricto and sensu lato Saccharomyces species, 80% of the predicted interactions displayed some evidence of combinatorial transcriptional behavior in several existing datasets including: (1 chromatin immunoprecipitation data for colocalization of transcription factors, (2 gene expression data for coexpression of predicted regulatory targets, and (3 gene ontology databases for common pathway membership of predicted regulatory targets. We tested several predicted CRE interactions with chromatin immunoprecipitation experiments in a wild-type strain and strains in which a predicted cofactor was deleted. Our experiments confirmed that transcription factor (TF occupancy at the promoters of the CRE combination target genes depends on the predicted cofactor while occupancy of other promoters is independent of the predicted cofactor. Our method has the additional advantage of identifying regulatory differences between species. By analyzing the S. cerevisiae and S. bayanus genomes, we identified differences in combinatorial cis-regulation between the species and showed that the predicted changes in gene regulation explain several of the species-specific differences seen in gene expression datasets. In some instances, the same CRE combinations appear to regulate genes involved in distinct biological processes in the two different species. The results of this research demonstrate that (1 combinatorial cis-regulation can be inferred by multi-genome analysis and (2 combinatorial cis-regulation can explain differences in gene expression between species.

  13. Isolation of the thymidylate synthetase gene (TMP1) by complementation in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Taylor, G.R.; Barclay, B.J.; Storms, R.K.; Friesen, J.D.; Haynes, R.H.

    1982-01-01

    The structural gene (TMP1) for yeast thymidylate synthetase (thymidylate synthase; EC 2.1.1.45) was isolated from a chimeric plasmid bank by genetic complementation in Saccharomyces cerevisiae. Retransformation of the dTMP auxotroph GY712 and a temperature-sensitive mutant (cdc21) with purified plasmid (pTL1) yielded Tmp/sup +/ transformants at high frequency. In addition, the plasmid was tested for the ability to complement a bacterial thyA mutant that lacks functional thymidylate synthetase. Although it was not possible to select Thy/sup +/ transformants directly, it was found that all pTL1 transformants were phenotypically Thy/sup +/ after several generations of growth in nonselective conditions. Thus, yeast thymidylate synthetase is biologically active in Escherichia coli. Thymidylate synthetase was assayed in yeast cell lysates by high-pressure liquid chromatography to monitor the conversion of [6-/sup 3/H]dUMP to [6-/sup 3/H]dTMP. In protein extracts from the thymidylate auxotroph (tmpl-6) enzymatic conversion of dUMP to dTMP was barely detectable. Lysates of pTL1 transformants of this strain, however, had thymidylate synthetase activity that was comparable to that of the wild-type strain

  14. Identification and functional analysis of the Saccharomyces cerevisiae nicotinamidase gene, PNC1.

    Science.gov (United States)

    Ghislain, Michel; Talla, Emmanuel; François, Jean M

    2002-02-01

    Nicotinamidase (NAMase) from the budding yeast, Saccharomyces cerevisiae, was purified by Ni(2+) affinity chromatography and gel filtration. N-terminal microsequencing revealed sequence identity with a hypothetical polypeptide encoded by the yeast YGL037C open reading frame sharing 30% sequence identity with Escherichia coli pyrazinamidase/nicotinamidase. A yeast strain in which the NAMase gene, hereafter named PNC1, was deleted shows a decreased intracellular NAD(+) concentration, consistent with the loss of NAMase activity in the null mutant. In wild-type strains, NAMase activity is stimulated during the stationary phase of growth, by various hyperosmotic shocks or by ethanol treatment. Using a P(PNC1)::lacZ gene fusion, we have shown that this stimulation of NAMase activity results from increased levels of the protein and requires stress response elements in the 5'non-coding region of PNC1. These results suggest that NAMase helps yeast cells to adapt to various stress conditions and nutrient depletion, most likely via the activation of NAD-dependent biological processes. Copyright 2002 John Wiley & Sons, Ltd.

  15. Expression of Human CTP Synthetase in Saccharomyces cerevisiae Reveals Phosphorylation by Protein Kinase A*

    Science.gov (United States)

    Han, Gil-Soo; Sreenivas, Avula; Choi, Mal-Gi; Chang, Yu-Fang; Martin, Shelley S.; Baldwin, Enoch P.; Carman, George M.

    2005-01-01

    CTP synthetase (EC 6.3.4.2, UTP: ammonia ligase (ADP-forming)) is an essential enzyme in all organisms; it generates the CTP required for the synthesis of nucleic acids and membrane phospholipids. In this work we showed that the human CTP synthetase genes, CTPS1 and CTPS2, were functional in Saccharomyces cerevisiae and complemented the lethal phenotype of the ura7Δ ura8Δ mutant lacking CTP synthetase activity. The expression of the CTPS1-and CTPS2-encoded human CTP synthetase enzymes in the ura7Δ ura8Δ mutant was shown by immunoblot analysis of CTP synthetase proteins, the measurement of CTP synthetase activity, and the synthesis of CTP in vivo. Phosphoamino acid and phosphopeptide mapping analyses of human CTP synthetase 1 isolated from 32Pi-labeled cells revealed that the enzyme was phosphorylated on multiple serine residues in vivo. Activation of protein kinase A activity in yeast resulted in transient increases (2-fold) in the phosphorylation of human CTP synthetase 1 and the cellular level of CTP. Human CTP synthetase 1 was also phosphorylated by mammalian protein kinase A in vitro. Using human CTP synthetase 1 purified from Escherichia coli as a substrate, protein kinase A activity was dose- and time-dependent, and dependent on the concentrations of CTP synthetase1 and ATP. These studies showed that S. cerevisiae was useful for the analysis of human CTP synthetase phosphorylation. PMID:16179339

  16. [Effects of non-saccharomyces albicans metabolic products on the proliferation of human umbilical vein endothelial cell ECV304].

    Science.gov (United States)

    Chen, Bin; Che, Tuanjie; Bai, Decheng; He, Xiangyi

    2013-04-01

    To evaluate the effects of non-Saccharomyces albicans metabolic products on the cell cycle distribution and proliferation of human umbilical vein endothelial cell ECV304 cells in vitro. The parallel dilution supernatant of Saccharomyces tropicalis, Saccharomyces krusei and Saccharomyces glabrata were prepared, and 1, 4, 16-fold(s) diluted concentration and control group were set up. The line of human umbilical vein endothelial cell ECV304 was cultured in vitro and treated by non-Saccharomyces albicans supernatant. The proliferous effect of ECV304 induced by non-Saccharomyces albicans supernatant after 24, 48, 72 h was detected by the methods of MTT, and the changes of cell density and cycle after 48 h were investigated by inverted microscope and flow cytometry. At the 24th hour, all of the higher concentration (1-fold) of non-Saccharomyces albicans supernatant and the 4-folds diluted Saccharomyces krusei could promote ECV304 proliferation(P Saccharomyces albicans supernatant at 48h and 72th hour, Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant significantly increased proliferation rate of ECV304, while Saccharomyces tropicalis supernatant group showed no significant change no matter which concentration was tested. At 48th hour after adding the non-Saccharomyces albicans supernatant, the ECV304 cells density treated by Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant were significantly higher under the inverted microscope. The G0/G1 population of ECV304 cells decreased while cell proliferation index (PI) increased after incubated with Saccharomyces krusei supernatant and Saccharomyces glabrata supernatant for 48 hours (P Saccharomyces tropicalis group showed no significant change (P > 0.05). The metabolic products of Sacharoymces krusei and Saccharomyces glabrata could induce proliferation of ECV304 cell, which suggests non-Saccharomyces albicans should be undergone more attention clinically in detection and treatment.

  17. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    OpenAIRE

    Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  18. Growth of non-Saccharomyces yeasts affects nutrient availability for Saccharomyces cerevisiae during wine fermentation.

    Science.gov (United States)

    Medina, Karina; Boido, Eduardo; Dellacassa, Eduardo; Carrau, Francisco

    2012-07-02

    Yeast produces numerous secondary metabolites during fermentation that impact final wine quality. Although it is widely recognized that growth of diverse non-Saccharomyces (NS) yeast can positively affect flavor complexity during Saccharomyces cerevisiae wine fermentation, the inability to control spontaneous or co-fermentation processes by NS yeast has restricted their use in winemaking. We selected two NS yeasts from our Uruguayan native collection to study NS-S. cerevisiae interactions during wine fermentation. The selected strains of Hanseniaspora vineae and Metschnikowia pulcherrima had different yeast assimilable nitrogen consumption profiles and had different effects on S. cerevisiae fermentation and growth kinetics. Studies in which we varied inoculum size and using either simultaneous or sequential inoculation of NS yeast and S. cerevisiae suggested that competition for nutrients had a significant effect on fermentation kinetics. Sluggish fermentations were more pronounced when S. cerevisiae was inoculated 24h after the initial stage of fermentation with a NS strain compared to co-inoculation. Monitoring strain populations using differential WL nutrient agar medium and fermentation kinetics of mixed cultures allowed for a better understanding of strain interactions and nutrient addition effects. Limitation of nutrient availability for S. cerevisiae was shown to result in stuck fermentations as well as to reduce sensory desirability of the resulting wine. Addition of diammonium phosphate (DAP) and a vitamin mix to a defined medium allowed for a comparison of nutrient competition between strains. Addition of DAP and the vitamin mix was most effective in preventing stuck fermentations. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Comparative ultraviolet action spectra (254-320 nm) of five wild-type eukaryotic microorganisms and Escherichia coli

    International Nuclear Information System (INIS)

    Calkins, J.; Wheeler, J.S.; Keller, C.I.; Colley, E.; Hazle, J.D.

    1988-01-01

    The action spectra of five eukaryotic organisms and the prokaryote, Escherichia coli, were examined over the wavelength range, 254-320 nm. Both the repair competent and three repair defective strains (E. coli, Caenorhabditis elegans, Saccharomyces) were examined. Tetrahymena pyriformis action spectra were performed with and without the excision repair inhibitor caffeine present. Others have observed that lethality, mutation, and the production of pyrimidine dimers show much the same wavelength dependence as DNA absorption. The results presented here demonstrate several action spectra which deviate from the DNA absorption spectra. Ultraviolet sensitization ratios (repair competent/repair defective) were also examined and were shown to change over the wavelength range. These findings suggest that DNA may not be the only important chromophore leading to cell death in the uv wavelength range studied. Since uv-B is of major importance in solar uv damage, these findings may also yield important implications for solar uv studies

  20. Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Jongedijk, E.J.; Cankar, K.; Ranzijn, J.; Krol, van der A.R.; Bouwmeester, H.J.; Beekwilder, M.J.

    2015-01-01

    Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (-)-limonene synthase from Perilla frutescens and a

  1. Reducing the genetic complexity of glycolysis in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Solis Escalante, D.

    2015-01-01

    Glycolysis, a biochemical pathway that oxidizes glucose to pyruvate, is at the core of sugar metabolism in Saccharomyces cerevisiae (bakers’ yeast). Glycolysis is not only a catabolic route involved in energy conservation, but also provides building blocks for anabolism. From an applied perspective,

  2. Silver Uptake and Reuse of Biomass by Saccharomyces cerevisiae ...

    African Journals Online (AJOL)

    Studies were carried out on the recovery of bound silver and reuse of Chlorella emersonii and Saccharomyces cerevisiae biomass for further silver uptake after they were placed in contact with 20mg/l silver for 30 minutes to allow for maximum binding. It was found that 0.16M nitric acid gave the best recovery rates of silver.

  3. Production of Saccharomyces cerevisiae biomass in papaya extract ...

    African Journals Online (AJOL)

    Extracts of papaya fruit were used as substrate for single cell protein (SCP) production using Saccharomyces cerevisiae. A 500 g of papaya fruit was extracted with different volumes of sterile distilled water. Extraction with 200 mL of sterile distilled water sustained highest cell growth. Biochemical analysis of dry biomass ...

  4. Engineering of aromatic amino acid metabolism in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Vuralhan, Z.

    2006-01-01

    Saccharomyces cerevisiae is a popular industrial microorganism. It has since long been used in bread, beer and wine making. More recently it is also being applied for heterologous protein production and as a target organism for metabolic engineering. The work presented in this thesis describes how

  5. Anti-Oxidant effects of pomegranate juice on Saccharomyces ...

    African Journals Online (AJOL)

    Conclusion: Pomegranate juice has a positive effect on fatty acid, vitamin and protein synthesis by Saccharomyces cerevisiae. Accordingly, we believe that it has significantly decreased oxidative damage thereby making a positive impact on yeast development. Key words: Pomegranate juice, SDS-PAGE, fatty acid, vitamin.

  6. Novel feeding strategies for Saccharomyces cerevisiae DS2155 ...

    African Journals Online (AJOL)

    The dual behavior of Saccharomyces cerevisiae on glucose feed as function of the dilution rate near the critical specific growth rate (ì=0.25) is a bottleneck in industrial production, hence the need for more efficient feeding strategies. In this work novel feeding strategies have been generated and evaluated. For each feeding ...

  7. Thermal resistance of Saccharomyces yeast ascospores in beers.

    Science.gov (United States)

    Milani, Elham A; Gardner, Richard C; Silva, Filipa V M

    2015-08-03

    The industrial production of beer ends with a process of thermal pasteurization. Saccharomyces cerevisiae and Saccharomyces pastorianus are yeasts used to produce top and bottom fermenting beers, respectively. In this research, first the sporulation rate of 12 Saccharomyces strains was studied. Then, the thermal resistance of ascospores of three S. cerevisiae strains (DSMZ 1848, DSMZ 70487, Ethanol Red(®)) and one strain of S. pastorianus (ATCC 9080) was determined in 4% (v/v) ethanol lager beer. D60 °C-values of 11.2, 7.5, 4.6, and 6.0 min and z-values of 11.7, 14.3, 12.4, and 12.7 °C were determined for DSMZ 1848, DSMZ 70487, ATCC 9080, and Ethanol Red(®), respectively. Lastly, experiments with 0 and 7% (v/v) beers were carried out to investigate the effect of ethanol content on the thermal resistance of S. cerevisiae (DSMZ 1848). D55 °C-values of 34.2 and 15.3 min were obtained for 0 and 7% beers, respectively, indicating lower thermal resistance in the more alcoholic beer. These results demonstrate similar spore thermal resistance for different Saccharomyces strains and will assist in the design of appropriate thermal pasteurization conditions for preserving beers with different alcohol contents. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Adsorption and Interfacial Electron Transfer of Saccharomyces Cerevisiae

    DEFF Research Database (Denmark)

    Hansen, Allan Glargaard; Boisen, Anja; Nielsen, Jens Ulrik

    2003-01-01

    We have studied the adsorption and electron-transfer dynamics of Saccharomyces cerevisiae (yeast) iso-l-cytochrome c adsorbed on Au(lll) electrodes in aqueous phosphate buffer media. This cytochrome possesses a thiol group dos e to the protein surface (Cysl02) suitable for linking the protein...

  9. Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth; Gro Rejkjær Sørensen, Laura

    2014-01-01

    than free-living cells. We investigated the genetic basis for yeast, Saccharomyces cerevisiae, biofilm on solid surfaces in liquid medium by screening a comprehensive deletion mutant collection in the S1278b background and found 71 genes that were essential for biofilm development. Quantitative...

  10. Stoichiometric network constraints on xylose metabolism by recombinant Saccharomyces cerevisiae

    Science.gov (United States)

    Yong-Su Jin; Thomas W. Jeffries

    2004-01-01

    Metabolic pathway engineering is constrained by the thermodynamic and stoichiometric feasibility of enzymatic activities of introduced genes. Engineering of xylose metabolism in Saccharomyces cerevisiae has focused on introducing genes for the initial xylose assimilation steps from Pichia stipitis, a xylose-fermenting yeast, into S. cerevisiae, a yeast raditionally...

  11. Evidence against a photoprotective component of photoreactivation in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    MacQuillan, A.M.; Green, G.; Perry, W.G.

    1981-01-01

    Photoreactivation-deficient (phr - ) mutants of Saccharomyces cerevisiae were shown to lack in vitro DNA-photolyase activity. A phr - mutant was then compared with a phr + strain for near-UV induced photoprotection from far-UV irradiation. Neither strain exhibited a photoprotective effect. (author)

  12. High-rate evolution of Saccharomyces sensu lato chromosomes

    DEFF Research Database (Denmark)

    Spirek, M.; Yang, J.; Groth, C.

    2003-01-01

    Forty isolates belonging to the Saccharomyces sensu lato complex were analyzed for one nuclear and two mitochondrial sequences, and for their karyotypes. These data are useful for description and definition of yeast species based on the phylogenetic species concept. The deduced phylogenetic...

  13. Kinetics of formation of induced mutants of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Chepurnoj, A.I.; Levkovich, N.V.; Mikhova-Tsenova, N.; Mel'nikova, L.A.

    1990-01-01

    UV and γ-radiation mutagenic effect an various strains of Saccharomyces cerevisiae was studied by analyzing formation kinetics of induced mutants at the period of postirradiation incubation. Mechanisms of induced reverse formation was suggested. The presented analysis is considered to be differential taking account of more subtle aspects of induced mutagenesis. 8 refs.; 10 figs.; 3 tabs

  14. Saccharomyces cerevisiae engineered for xylose metabolism exhibits a respiratory response

    Science.gov (United States)

    Yong-Su Jin; Jose M. Laplaza; Thomas W. Jeffries

    2004-01-01

    Native strains of Saccharomyces cerevisiae do not assimilate xylose. S. cerevisiae engineered for D-xylose utilization through the heterologous expression of genes for aldose reductase ( XYL1), xylitol dehydrogenase (XYL2), and D-xylulokinase ( XYL3 or XKS1) produce only limited amounts of ethanol in xylose medium. In recombinant S. cerevisiae expressing XYL1, XYL2,...

  15. Reconstitution of an efficient thymidine salvage pathway in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vernis, L.; Piskur, Jure; Diffley, J.F.X.

    2003-01-01

    The budding yeast Saccharomyces cerevisiae is unable to incorporate exogenous nucleosides into DNA. We have made a number of improvements to existing strategies to reconstitute an efficient thymidine salvage pathway in yeast. We have constructed strains that express both a nucleoside kinase as well...

  16. Social wasps promote social behavior in Saccharomyces spp.

    Science.gov (United States)

    This commentary provides background and an evaluation of a paper to be published in the Proceedings of the National Academy of Sciences in which social wasps were found to harbor significant populations of two species of the yeast genus Saccharomyces. Apparently, the yeasts were acquired during feed...

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

    Science.gov (United States)

    Deutch, Charles E.; Marshall, Pamela A.

    2008-01-01

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

  18. Mead features fermented by Saccharomyces cerevisiae (lalvin k1 ...

    African Journals Online (AJOL)

    Eduardo Morales

    Full Length Research Paper. Mead features fermented by Saccharomyces cerevisiae. (lalvin k1-1116). Eduardo Marin MORALES1*, Valmir Eduardo ALCARDE2 and Dejanira de Franceschi de. ANGELIS1. 1Department of Biochemistry and Microbiology, Institute of Biosciences, UNESP - Univ Estadual Paulista, Av. 24-A,.

  19. Potential application of Saccharomyces cerevisiae strains for the ...

    African Journals Online (AJOL)

    This paper aimed at evaluating the fermentation behavior of selected Saccharomyces cerevisiae strains in banana pulp and they were compared with commercial yeast (baker's yeast) for subsequent production of distilled spirits. Five types of microorganisms were used: Four yeast strains obtained from accredited ...

  20. Evolutionary engineering of Saccharomyces cerevisiae for efficient aerobic xylose consumption

    DEFF Research Database (Denmark)

    Scalcinati, Gionata; Otero, José Manuel; Van Vleet, Jennifer R. H.

    2012-01-01

    Industrial biotechnology aims to develop robust microbial cell factories, such as Saccharomyces cerevisiae, to produce an array of added value chemicals presently dominated by petrochemical processes. Xylose is the second most abundant monosaccharide after glucose and the most prevalent pentose s...

  1. Study on extract dates syrup fermentation using Saccharomyces ...

    African Journals Online (AJOL)

    Customer

    2012-04-24

    Apr 24, 2012 ... conversion. A high fructose yield above 91% of the original fructose was obtained with ATCC 36858. In addition, the ethanol yield was found to be 63% of the theoretical. Key words: Saccharomyces cerevisiae, fructose, glucose, bioethanol, fermentation. INTRODUCTION. Sugars are carbohydrate materials ...

  2. Effects of dietary L-threonine and Saccharomyces cerevisiae on ...

    African Journals Online (AJOL)

    threonine (0, 2.5, 5 and 7.5 g/kg) with or without Saccharomyces cerevisiae (SC) on performance, carcass characteristics, intestinal morphology and immune system of broiler chickens. A total of 360 1-d-old male broiler chicks were randomly ...

  3. Industrial relevance of chromosomal copy number variation in Saccharomyces yeasts

    NARCIS (Netherlands)

    Gorter de Vries, A.R.; Pronk, J.T.; Daran, J.G.

    2017-01-01

    Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have

  4. Influence of Two Inocula Levels of Saccharomyces bayanus on ...

    African Journals Online (AJOL)

    pc

    2012-04-02

    Apr 2, 2012 ... The influence of two inocula levels of the yeast Saccharomyces bayanus, ... Wine is usually made through fermentation of grape juice. ... strain of the yeast and the level of yeast inoculated are .... culture of S. cerevisiae and Williopsis saturnus and ... have acid taste index values of two to three and dry white.

  5. Novel feeding strategies for Saccharomyces cerevisiae DS2155 ...

    African Journals Online (AJOL)

    Administrator

    2007-05-02

    May 2, 2007 ... processes. The software also ensured the updating of the feed flow rate every 5 min for 24 h. The ... But, the exact location and amplitude ..... glucose effect in the Yeast Saccharomyces uvarum: involvement of short, and long ...

  6. Saccharomyces cerevisiae boulardii transient fungemia after intravenous self-inoculation

    OpenAIRE

    Cohen, Lola; Ranque, Stéphane; Raoult, Didier

    2013-01-01

    We report the case of a young psychotic intravenous drug user injecting herself with Saccharomyces cervisiae (boulardii). She experienced a 24 h fever, resolving spontaneously confirming, quasi experimentally, the inocuity of this yeast in a non-immunocompromised host.

  7. Switching the mode of sucrose utilization by Saccharomyces cerevisiae

    OpenAIRE

    Badotti, Fernanda; Dário, Marcelo G; Alves, Sergio L; Cordioli, Maria Luiza A; Miletti, Luiz C; de Araujo, Pedro S; Stambuk, Boris U

    2008-01-01

    Abstract Background Overflow metabolism is an undesirable characteristic of aerobic cultures of Saccharomyces cerevisiae during biomass-directed processes. It results from elevated sugar consumption rates that cause a high substrate conversion to ethanol and other bi-products, severely affecting cell physiology, bioprocess performance, and biomass yields. Fed-batch culture, where sucro...

  8. The effects of different concentrations of probiotic Saccharomyces ...

    African Journals Online (AJOL)

    In the present study, a yeast strain Saccharomyces cerevisia var. elipsoidous, acting as probiotic, was administered to rainbow trout (Oncorhynchus mykiss Walbaum, 1792) fry during a period of 21 days and the effects of the yeast on improvement of growth and resistance against environmental stress were evaluated with ...

  9. The Plasma Membrane of Saccharomyces cerevisiae : Structure, Function, and Biogenesis

    NARCIS (Netherlands)

    VANDERREST, ME; KAMMINGA, AH; NAKANO, A; ANRAKU, Y; POOLMAN, B; KONINGS, WN

    The composition of phospholipids, sphingolipids, and sterols in the plasma membrane has a strong influence on the activity of the proteins associated or embedded in the lipid bilayer. Since most lipid-synthesizing enzymes in Saccharomyces cerevisiae are located in intracellular organelles, an

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jennifer R Bellon

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

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

    Science.gov (United States)

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

    2013-01-01

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

  13. Photoreactivating enzyme from Escherichia coli

    International Nuclear Information System (INIS)

    Snapka, R.M.; Fuselier, C.O.

    1977-01-01

    Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm. (author)

  14. Photoreactivating enzyme from Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Snapka, R M; Fuselier, C O [California Univ., Irvine (USA)

    1977-05-01

    Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm.

  15. Expression in E. coli systems

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Kristiansen, Karsten; Nøhr, Jane

    2003-01-01

    intracellularly in soluble form. In E. coli, proteins containing disulfide bonds are best produced by secretion because the disulfide forming foldases reside in the periplasm. Likewise, a correct N-terminus is more likely to be obtained upon secretion. Moreover, potentially toxic proteins are more likely......Owing to cost advantage, speed of production, and often high product yield (up to 50% of total cell protein), expression in Escherichia coli is generally the first choice when attempting to express a recombinant protein. Expression systems exist to produce recombinant protein intracellularly...

  16. Experimental evolution of E. coli

    Science.gov (United States)

    Zhang, Mengshi

    The evolution from unicellular to multicellular behavior is an essential step in the history of life. Our aim is to investigate the emergence of collective behavior in the model organism Escherichia coli (E. coli) and its selection advantages, such as better utilization of public goods. Our preliminary results suggest that the evolution of collective behavior may be a natural response to stressed conditions. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: mengshi0928@gmail.com.

  17. Outlining a future for non-Saccharomyces yeasts: selection of putative spoilage wine strains to be used in association with Saccharomyces cerevisiae for grape juice fermentation.

    Science.gov (United States)

    Domizio, Paola; Romani, Cristina; Lencioni, Livio; Comitini, Francesca; Gobbi, Mirko; Mannazzu, Ilaria; Ciani, Maurizio

    2011-06-30

    The use of non-Saccharomyces yeasts that are generally considered as spoilage yeasts, in association with Saccharomyces cerevisiae for grape must fermentation was here evaluated. Analysis of the main oenological characteristics of pure cultures of 55 yeasts belonging to the genera Hanseniaspora, Pichia, Saccharomycodes and Zygosaccharomyces revealed wide biodiversity within each genus. Moreover, many of these non-Saccharomyces strains had interesting oenological properties in terms of fermentation purity, and ethanol and secondary metabolite production. The use of four non-Saccharomyces yeasts (one per genus) in mixed cultures with a commercial S. cerevisiae strain at different S. cerevisiae/non-Saccharomyces inoculum ratios was investigated. This revealed that most of the compounds normally produced at high concentrations by pure cultures of non-Saccharomyces, and which are considered detrimental to wine quality, do not reach threshold taste levels in these mixed fermentations. On the other hand, the analytical profiles of the wines produced by these mixed cultures indicated that depending on the yeast species and the S. cerevisiae/non-Saccharomyces inoculum ratio, these non-Saccharomyces yeasts can be used to increase production of polysaccharides and to modulate the final concentrations of acetic acid and volatile compounds, such as ethyl acetate, phenyl-ethyl acetate, 2-phenyl ethanol, and 2-methyl 1-butanol. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. The oxygen effect in E. coli cells

    International Nuclear Information System (INIS)

    Myasnik, M.N.; Skvortsov, V.G.; Sokolov, V.A.

    1982-01-01

    In experiments on E. coli strains deficient in some stages of DNA repair from radiation damages, it was demonstrated that the value of the oxygen effect, under optimal conditions for manifestation thereof, decreases in the following order: E. coli WP2 (the wild type) → E. coli WP2 exr - and E. coli B → E. coli WP2 uvr A6 → E. coli WP2 rec Al and E. coli WP2 hcr - exr - . It was detected that 0.14 M NaCl solution sensitizes the anoxic cells of some E. coli strains to the effect of γ-radiation. It was established that mutation of the uvr A-gene increases sharply the sensitivity of cells to iradiation under the anoxic conditions in the presence of NaCl, the reverse'' oxygen effect being observed

  19. Clinical Efficacy Comparison of Saccharomyces Boulardii and Lactic Acid as Probiotics in Acute Pediatric Diarrhea.

    Science.gov (United States)

    Asmat, Shakila; Shaukat, Fouzia; Asmat, Raheela; Bakhat, Hafiz Faiq Siddique Gul; Asmat, Tauseef M

    2018-03-01

    To compare the efficacy of Saccharomyces boulardii and lactic acid producing probiotics in addition to usual treatment regimen to cure diarrhea among children (6 months to 5 years of age). Randomized controlled trial. Department of Pediatrics, Sheikh Zayed Hospital, Lahore, from February to July 2015. Children suffering from acute diarrhea were orally administered Saccharomyces boulardii and lactic acid producing probiotics for 5 days. The efficacy of administered probiotics was monitored. Patients were given Saccharomyces boulardii and lactic acid producing probiotics randomly to remove the bias. Two hundred patients randomly selected for trials; out of which, 100 were treated with Saccharomyces boulardii while the other 100 were supplemented with lactic acid concomitantly along with conventional diarrhea treatment. Results indicated that Saccharomyces boulardii treatment group has significantly higher efficacy rate (45%) compared to lactic acid producing probiotics (26%). This study concluded that Saccharomyces boulardii has a better efficacy compared to lactic acid and may be adopted as a probiotic of choice.

  20. Actions and advice in coli

    DEFF Research Database (Denmark)

    Knoche, Hendrik; Jamadagni, HS; Rao, PR Sheshagiri

    2015-01-01

    To improve their agricultural output, farmers require timely and contextualized information and advice. Relevant information and advice provided by trusted peers represents a promising approach. We present the considerations for the design of coli, an agricultural information network on touch scr...

  1. Infektionen mit darmpathogenen Escherichia coli.

    NARCIS (Netherlands)

    Friedrich, Alexander; Stein, Jürgen; Dignass, Axel

    2001-01-01

    E. coli ist ein wesentlicher Bestandteil der physiologischen Darmflora des Menschen. Die üblicherweise im Darm vorkommenden Kolibakterien sind apathogen und für den Menschen eher nützlich (Sonnenborn u. Greinwald 1990). Allerdings kennen wir bei dieser Bakterienspezies auch ein breites Spektrum von

  2. 76 FR 20542 - Escherichia coli

    Science.gov (United States)

    2011-04-13

    ... beef, Escherichia coli and coliphages were found in chicken, fresh pork, fresh oyster, fresh mushrooms, lettuce, chicken pot pie, biscuit dough, deli loaf, deli roasted turkey, and package roasted chicken... surfaces, and in foods such as ground beef, pork sausage, chicken, oysters, cheese, fresh mushrooms, and...

  3. ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. The bio-effects of the ethanol extracts from the leaf and stem of Momordica charantia were studied with the view to ascertain the medical usefulness ascribed to the plant by the locals. The plant parts, stem and leaf, revealed remarkable activity against Escherichia coli and Staphlococcus aureus. The leaves ...

  4. Conjugal Pairing in Escherichia Coli

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Conjugal Pairing in Escherichia Coli. Joshua Lederberg. Classics Volume 13 Issue 8 August 2008 pp 793-794. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/013/08/0793-0794 ...

  5. Escherichia coli as a probiotic?

    NARCIS (Netherlands)

    Jansen, GJ; Wildeboer-Veloo, ACM; van der Waaij, D; Degener, JE

    1998-01-01

    The influence of oral treatment with a suspension of non-pathogenic Escherichia coli cells (commercially available as: Symbioflor II(R)) on the morphological composition of the gut microflora and on the systemic humoral immune response (the IgG-, IgA- and IgM-isotype) against the bacterial cells in

  6. Expression in E. coli systems

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Kristiansen, Karsten; Nøhr, Jane

    2003-01-01

    intracellularly in soluble form. In E. coli, proteins containing disulfide bonds are best produced by secretion because the disulfide forming foldases reside in the periplasm. Likewise, a correct N-terminus is more likely to be obtained upon secretion. Moreover, potentially toxic proteins are more likely...

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

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  8. On the origins and industrial applications of Saccharomyces cerevisiae × Saccharomyces kudriavzevii hybrids.

    Science.gov (United States)

    Peris, David; Pérez-Torrado, Roberto; Hittinger, Chris Todd; Barrio, Eladio; Querol, Amparo

    2018-01-01

    Companies based on alcoholic fermentation products, such as wine, beer and biofuels, use yeasts to make their products. Each industrial process utilizes different media conditions, which differ in sugar content, the presence of inhibitors and fermentation temperature. Saccharomyces cerevisiae has traditionally been the main yeast responsible for most fermentation processes. However, the market is changing due to consumer demand and external factors such as climate change. Some processes, such as biofuel production or winemaking, require new yeasts to solve specific challenges, especially those associated with sustainability, novel flavours and altered alcohol content. One of the proposed solutions is the application of yeast hybrids. The lager beer market has been dominated by S. cerevisiae × S. eubayanus hybrids. However, several less thoroughly studied hybrids have been isolated from other diverse industrial processes. Here we focus on S. cerevisiae × S. kudriavzevii hybrids, which have been isolated from diverse industrial conditions that include wine, ale beer, cider and dietary supplements. Emerging data suggest an extended and complex story of adaptation of these hybrids to traditional industrial conditions. S. cerevisiae × S. kudriavzevii hybrids are also being explored for new industrial applications, such as biofuels. This review describes the past, present and future of S. cerevisiae × S. kudriavzevii hybrids. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. 99mTechnetium labelled Escherichia coli

    International Nuclear Information System (INIS)

    Diniz, S.O.F.; Cardoso, V.N.; Resende, B.M.; Nunan, E.A.; Simal, C.J.R.

    1999-01-01

    Samples of a culture of unlabeled Escherichia coli were incubated with different concentrations of stannous chloride for various time periods. 99m Tc (26.0 MBq) was added to each preparation and the results showed a labelling yield of 98% for E. coli. Since the bacterial viability of 99m Tc-E. coli and E. coli did not show any statistical differences, these results demonstrate that labelling of E. coli with 99m Tc does not modify the bacterial viability, and the radiolabelled bacteria may be a good model to study bacterial translocation

  10. Influence of organic acids and organochlorinated insecticides on metabolism of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Pejin Dušanka J.

    2005-01-01

    Full Text Available Saccharomyces cerevisiae is exposed to different stress factors during the production: osmotic, temperature, oxidative. The response to these stresses is the adaptive mechanism of cells. The raw materials Saccharomyces cerevisiae is produced from, contain metabolism products of present microorganisms and protective agents used during the growth of sugar beet for example the influence of acetic and butyric acid and organochlorinated insecticides, lindan and heptachlor, on the metabolism of Saccharomyces cerevisiae was investigated and presented in this work. The mentioned compounds affect negatively the specific growth rate, yield, content of proteins, phosphorus, total ribonucleic acids. These compounds influence the increase of trechalose and glycogen content in the Saccharomyces cerevisiae cells.

  11. Efficient engineering of marker-free synthetic allotetraploids of Saccharomyces.

    Science.gov (United States)

    Alexander, William G; Peris, David; Pfannenstiel, Brandon T; Opulente, Dana A; Kuang, Meihua; Hittinger, Chris Todd

    2016-04-01

    Saccharomyces interspecies hybrids are critical biocatalysts in the fermented beverage industry, including in the production of lager beers, Belgian ales, ciders, and cold-fermented wines. Current methods for making synthetic interspecies hybrids are cumbersome and/or require genome modifications. We have developed a simple, robust, and efficient method for generating allotetraploid strains of prototrophic Saccharomyces without sporulation or nuclear genome manipulation. S. cerevisiae×S. eubayanus, S. cerevisiae×S. kudriavzevii, and S. cerevisiae×S. uvarum designer hybrid strains were created as synthetic lager, Belgian, and cider strains, respectively. The ploidy and hybrid nature of the strains were confirmed using flow cytometry and PCR-RFLP analysis, respectively. This method provides an efficient means for producing novel synthetic hybrids for beverage and biofuel production, as well as for constructing tetraploids to be used for basic research in evolutionary genetics and genome stability. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Purification of Arp2/3 complex from Saccharomyces cerevisiae

    Science.gov (United States)

    Doolittle, Lynda K.; Rosen, Michael K.; Padrick, Shae B.

    2014-01-01

    Summary Much of cellular control over actin dynamics comes through regulation of actin filament initiation. At the molecular level, this is accomplished through a collection of cellular protein machines, called actin nucleation factors, which position actin monomers to initiate a new actin filament. The Arp2/3 complex is a principal actin nucleation factor used throughout the eukaryotic family tree. The budding yeast Saccharomyces cerevisiae has proven to be not only an excellent genetic platform for the study of the Arp2/3 complex, but also an excellent source for the purification of endogenous Arp2/3 complex. Here we describe a protocol for the preparation of endogenous Arp2/3 complex from wild type Saccharomyces cerevisiae. This protocol produces material suitable for biochemical study, and yields milligram quantities of purified Arp2/3 complex. PMID:23868593

  13. Exploring Protein Function Using the Saccharomyces Genome Database.

    Science.gov (United States)

    Wong, Edith D

    2017-01-01

    Elucidating the function of individual proteins will help to create a comprehensive picture of cell biology, as well as shed light on human disease mechanisms, possible treatments, and cures. Due to its compact genome, and extensive history of experimentation and annotation, the budding yeast Saccharomyces cerevisiae is an ideal model organism in which to determine protein function. This information can then be leveraged to infer functions of human homologs. Despite the large amount of research and biological data about S. cerevisiae, many proteins' functions remain unknown. Here, we explore ways to use the Saccharomyces Genome Database (SGD; http://www.yeastgenome.org ) to predict the function of proteins and gain insight into their roles in various cellular processes.

  14. Saccharomyces cerevisiae: a sexy yeast with a prion problem.

    Science.gov (United States)

    Kelly, Amy C; Wickner, Reed B

    2013-01-01

    Yeast prions are infectious proteins that spread exclusively by mating. The frequency of prions in the wild therefore largely reflects the rate of spread by mating counterbalanced by prion growth slowing effects in the host. We recently showed that the frequency of outcross mating is about 1% of mitotic doublings with 23-46% of total matings being outcrosses. These findings imply that even the mildest forms of the [PSI+], [URE3] and [PIN+] prions impart > 1% growth/survival detriment on their hosts. Our estimate of outcrossing suggests that Saccharomyces cerevisiae is far more sexual than previously thought and would therefore be more responsive to the adaptive effects of natural selection compared with a strictly asexual yeast. Further, given its large effective population size, a growth/survival detriment of > 1% for yeast prions should strongly select against prion-infected strains in wild populations of Saccharomyces cerevisiae.

  15. Human Meningitis-Associated Escherichia coli

    Science.gov (United States)

    KIM, KWANG SIK

    2016-01-01

    E. coli is the most common Gram-negative bacillary organism causing meningitis and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Our incomplete knowledge of its pathogenesis contributes to such mortality and morbidity. Recent reports of E. coli strains producing CTX-M-type or TEM-type extended-spectrum β-lactamases create a challenge. Studies using in vitro and in vivo models of the blood-brain barrier have shown that E. coli meningitis follows a high-degree of bacteremia and invasion of the blood-brain barrier. E. coli invasion of the blood-brain barrier, the essentials step in the development of E. coli meningitis, requires specific microbial and host factors as well as microbe- and host-specific signaling molecules. Blockade of such microbial and host factors contributing to E. coli invasion of the blood-brain barrier is shown to be efficient in preventing E. coli penetration into the brain. The basis for requiring a high-degree of bacteremia for E. coli penetration of the blood-brain barrier, however, remains unclear. Continued investigation on the microbial and host factors contributing to a high-degree of bacteremia and E. coli invasion of the blood-brain barrier is likely to identify new targets for prevention and therapy of E. coli meningitis. PMID:27223820

  16. Applied systems biology - vanillin production in Saccharomyces cerevisiae

    OpenAIRE

    Strucko, Tomas; Eriksen, Jens Christian; Nielsen, J.; Mortensen, Uffe Hasbro

    2012-01-01

    Vanillin is the most important aroma compound based on market value, and natural vanillin is extracted from the cured seed pods of the Vanilla orchid. Most of the world’s vanillin, however, is obtained by chemical synthesis from petrochemicals or wood pulp lignins. As an alternative, de novo biosynthesis of vanillin in baker’s yeast Saccharomyces cerevisiae was recently demonstrated by successfully introducing the metabolic pathway for vanillin production in yeast. Nevertheless, the amount of...

  17. Hydrogen peroxide removal with magnetically responsive Saccharomyces cerevisiae cells

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2008-01-01

    Roč. 56, - (2008), s. 7925-7928 ISSN 0021-8561 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate beads * catalase * magnetic separation * Saccharomyces cerevisiae cells * hydrogen peroxide Subject RIV: GM - Food Processing Impact factor: 2.562, year: 2008

  18. Microbially induced separation of quartz from calcite using Saccharomyces cerevisiae.

    Science.gov (United States)

    Padukone, S Usha; Natarajan, K A

    2011-11-01

    Cells of Saccharomyces cerevisiae and their metabolites were successfully utilized to achieve selective separation of quartz and calcite through microbially induced flotation and flocculation. S. cerevisiae was adapted to calcite and quartz minerals. Adsorption studies and electrokinetic investigations were carried out to understand the changes in the surface chemistry of yeast cells and the minerals after mutual interaction. Possible mechanisms in microbially induced flotation and flocculation are outlined. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Intracellular metabolite profiling of Saccharomyces cerevisiae evolved under furfural

    OpenAIRE

    Jung, Young Hoon; Kim, Sooah; Yang, Jungwoo; Seo, Jin?Ho; Kim, Kyoung Heon

    2016-01-01

    Summary Furfural, one of the most common inhibitors in pre?treatment hydrolysates, reduces the cell growth and ethanol production of yeast. Evolutionary engineering has been used as a selection scheme to obtain yeast strains that exhibit furfural tolerance. However, the response of Saccharomyces cerevisiae to furfural at the metabolite level during evolution remains unknown. In this study, evolutionary engineering and metabolomic analyses were applied to determine the effects of furfural on y...

  20. Oligoadenylate is present in the mitochondrial RNA of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Yuckenberg, P.D.; Phillips, S.L.

    1982-01-01

    The authors examined Saccharomyces cerevisiae mitochondrial RNA for polyadenylate. Using hybridization to [/sup 3/H]polyuridylate as the assay for adenylate sequences, they found adenylate-rich oligonucleotides approximately 8 residues long. Longer polyadenylate was not detected. Most of the adenylate-rich sequence is associated with the large mitochondrial rRNA. The remainder is associated with the 10-12S group of transcripts

  1. Dynamics of Storage Carbohydrates Metabolism in Saccharomyces cerevisiae

    OpenAIRE

    Suarez-Mendez, C.A.

    2015-01-01

    Production of chemicals via biotechnological routes are becoming rapidly an alternative to oil-based processes. Several microorganisms including yeast, bacteria, fungi and algae can transform feedstocks into high-value molecules at industrial scale. Improvement of the bioprocess performance is a key factor for making this technology economically feasible. Despite the vast knowledge on microbial metabolism, some gaps still remain open. In Saccharomyces cerevisiae, metabolism of storage carbohy...

  2. Biosynthesis and engineering of kaempferol in Saccharomyces cerevisiae

    OpenAIRE

    Duan, Lijin; Ding, Wentao; Liu, Xiaonan; Cheng, Xiaozhi; Cai, Jing; Hua, Erbing; Jiang, Huifeng

    2017-01-01

    Background Kaempferol is a flavonol with broad bioactivity of anti-oxidant, anti-cancer, anti-diabetic, anti-microbial, cardio-protective and anti-asthma. Microbial synthesis of kaempferol is a promising strategy because of the low content in primary plant source. Methods In this study, the biosynthesis pathway of kaempferol was constructed in the budding yeast Saccharomyces cerevisiae to produce kaempferol de novo, and several biological measures were taken for high production. Results First...

  3. Species Identification and Virulence Attributes of Saccharomyces boulardii (nom. inval.)

    Science.gov (United States)

    McCullough, Michael J.; Clemons, Karl V.; McCusker, John H.; Stevens, David A.

    1998-01-01

    Saccharomyces boulardii (nom. inval.) has been used for the treatment of several types of diarrhea. Recent studies have confirmed that S. boulardii is effective in the treatment of diarrhea, in particular chronic or recurrent diarrhea, and furthermore that it is a safe and well-tolerated treatment. The aim of the present study was to identify strains of S. boulardii to the species level and assess their virulence in established murine models. Three strains of S. boulardii were obtained from commercially available products in France and Italy. The three S. boulardii strains did not form spores upon repeated testing. Therefore, classical methods used for the identification of Saccharomyces spp. could not be undertaken. Typing by using the restriction fragment length polymorphisms (RFLPs) of the PCR-amplified intergenic transcribed spacer regions (including the 5.8S ribosomal DNA) showed that the three isolates of S. boulardii were not separable from authentic isolates of Saccharomyces cerevisiae with any of the 10 restriction endonucleases assessed, whereas 9 of the 10 recognized species of Saccharomyces could be differentiated. RFLP analysis of cellular DNA with EcoRI showed that all three strains of S. boulardii had identical patterns and were similar to other authentic S. cerevisiae isolates tested. Therefore, the commercial strains of S. boulardii available to us cannot be genotypically distinguished from S. cerevisiae. Two S. boulardii strains were tested in CD-1 and DBA/2N mouse models of systemic disease and showed intermediate virulence compared with virulent and avirulent strains of S. cerevisiae. The results of the present study show that these S. boulardii strains are asporogenous strains of the species S. cerevisiae, not representatives of a distinct and separate species, and possess moderate virulence in murine models of systemic infection. Therefore, caution should be advised in the clinical use of these strains in immunocompromised patients until

  4. Antibiotic effective against Saccharomyces produced by Aspergillus oryzae

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, H.; Sakai, T.; Takeda, M.; Tsukahara, T.

    1980-01-01

    Production of an antibiotic effective against Saccharomyces cerevisiae was investigated in 85 strains of Aspergillus oryzae, isolated from commercial koji molds. The antibiotic was produced by 50 strains. A. oryzae was cultivated at 30 degrees for 15-20 days in koji extract. The crude preparation was obtained by precipitation from the culture filtrate with EtOH, MeOH, or Me/sub 2/CO.

  5. Genomics and Biochemistry of Saccharomyces cerevisiae Wine Yeast Strains.

    Science.gov (United States)

    Eldarov, M A; Kishkovskaia, S A; Tanaschuk, T N; Mardanov, A V

    2016-12-01

    Saccharomyces yeasts have been used for millennia for the production of beer, wine, bread, and other fermented products. Long-term "unconscious" selection and domestication led to the selection of hundreds of strains with desired production traits having significant phenotypic and genetic differences from their wild ancestors. This review summarizes the results of recent research in deciphering the genomes of wine Saccharomyces strains, the use of comparative genomics methods to study the mechanisms of yeast genome evolution under conditions of artificial selection, and the use of genomic and postgenomic approaches to identify the molecular nature of the important characteristics of commercial wine strains of Saccharomyces. Succinctly, data concerning metagenomics of microbial communities of grapes and wine and the dynamics of yeast and bacterial flora in the course of winemaking is provided. A separate section is devoted to an overview of the physiological, genetic, and biochemical features of sherry yeast strains used to produce biologically aged wines. The goal of the review is to convince the reader of the efficacy of new genomic and postgenomic technologies as tools for developing strategies for targeted selection and creation of new strains using "classical" and modern techniques for improving winemaking technology.

  6. Mitochondrial genome evolution in the Saccharomyces sensu stricto complex.

    Science.gov (United States)

    Ruan, Jiangxing; Cheng, Jian; Zhang, Tongcun; Jiang, Huifeng

    2017-01-01

    Exploring the evolutionary patterns of mitochondrial genomes is important for our understanding of the Saccharomyces sensu stricto (SSS) group, which is a model system for genomic evolution and ecological analysis. In this study, we first obtained the complete mitochondrial sequences of two important species, Saccharomyces mikatae and Saccharomyces kudriavzevii. We then compared the mitochondrial genomes in the SSS group with those of close relatives, and found that the non-coding regions evolved rapidly, including dramatic expansion of intergenic regions, fast evolution of introns and almost 20-fold higher rearrangement rates than those of the nuclear genomes. However, the coding regions, and especially the protein-coding genes, are more conserved than those in the nuclear genomes of the SSS group. The different evolutionary patterns of coding and non-coding regions in the mitochondrial and nuclear genomes may be related to the origin of the aerobic fermentation lifestyle in this group. Our analysis thus provides novel insights into the evolution of mitochondrial genomes.

  7. Industrial Relevance of Chromosomal Copy Number Variation in Saccharomyces Yeasts.

    Science.gov (United States)

    Gorter de Vries, Arthur R; Pronk, Jack T; Daran, Jean-Marc G

    2017-06-01

    Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have contributed to an extensive set of methods for analyzing and introducing CCNV. Moreover, these studies provided insight into the balance between negative and positive impacts of CCNV in evolutionary contexts. A growing body of evidence indicates that CCNV not only frequently occurs in industrial strains of Saccharomyces yeasts but also is a key contributor to the diversity of industrially relevant traits. This notion is further supported by the frequent involvement of CCNV in industrially relevant traits acquired during evolutionary engineering. This review describes recent developments in genome sequencing and genome editing techniques and discusses how these offer opportunities to unravel contributions of CCNV in industrial Saccharomyce s strains as well as to rationally engineer yeast chromosomal copy numbers and karyotypes. Copyright © 2017 Gorter de Vries et al.

  8. Expression of the human blood coagulation protein factor XIIIa in Saccharomyces cerevisiae: dependence of the expression levels from host-vector systems and medium conditions.

    Science.gov (United States)

    Bröker, M; Bäuml, O; Göttig, A; Ochs, J; Bodenbenner, M; Amann, E

    1991-03-01

    The human blood coagulation protein Factor XIIIa (FXIIIa) was expressed in Saccharomyces cerevisiae employing Escherichia coli-yeast shuttle vectors based on a 2-mu plasmid. Several factors affecting high production yield of recombinant FXIIIa were analysed. The use of the regulatable GAL-CYC1 hybrid promoter resulted in higher FXIIIa expression when compared with the constitutive ADCI promoter. Screening for suitable yeast strains for expression of FXIIIa under the transcriptional control of the GAL-CYC1 hybrid promoter revealed a broad spectrum of productivity. No obvious correlation between the expression rate and the genetic markers of the strains could be identified. The medium composition markedly influenced the FXIIIa expression rates. The expression of FXIIIa was strictly regulated by the carbon source. Glucose as the only sugar and energy source repressed the synthesis of FXIIIa, whereas addition of galactose induced FXIIIa expression. Special feeding schemes resulted in a productivity of up to 100 mg FXIIIa/l in shake flasks.

  9. Transcriptome-Based Characterization of Interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in Lactose-Grown Chemostat Cocultures

    NARCIS (Netherlands)

    Mendes, F.; Sieuwerts, S.; De Hulster, E.; Almering, M.J.; Luttik, M.A.; Pronk, J.T.; Smid, E.J.; Bron, P.A.; Daran-Lapujade, P.

    2013-01-01

    Mixed populations of Saccharomyces cerevisiae yeasts and lactic acid bacteria occur in many dairy, food, and beverage fermentations, but knowledge about their interactions is incomplete. In the present study, interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp.

  10. Transcriptome-based characterization of interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in lactose-grown chemostat cocultures

    NARCIS (Netherlands)

    Mendes, F.; Sieuwerts, S.; Hulster, de E.; Almering, M.J.; Luttik, M.A.H.; Pronk, J.T.; Smid, E.J.; Baron, P.A.; Daran-Lapujade, P.

    2013-01-01

    Mixed populations of Saccharomyces cerevisiae yeasts and lactic acid bacteria occur in many dairy, food, and beverage fermentations, but knowledge about their interactions is incomplete. In the present study, interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp.

  11. A tetO Toolkit To Alter Expression of Genes in Saccharomyces cerevisiae.

    Science.gov (United States)

    Cuperus, Josh T; Lo, Russell S; Shumaker, Lucia; Proctor, Julia; Fields, Stanley

    2015-07-17

    Strategies to optimize a metabolic pathway often involve building a large collection of strains, each containing different versions of sequences that regulate the expression of pathway genes. Here, we develop reagents and methods to carry out this process at high efficiency in the yeast Saccharomyces cerevisiae. We identify variants of the Escherichia coli tet operator (tetO) sequence that bind a TetR-VP16 activator with differential affinity and therefore result in different TetR-VP16 activator-driven expression. By recombining these variants upstream of the genes of a pathway, we generate unique combinations of expression levels. Here, we built a tetO toolkit, which includes the I-OnuI homing endonuclease to create double-strand breaks, which increases homologous recombination by 10(5); a plasmid carrying six variant tetO sequences flanked by I-OnuI sites, uncoupling transformation and recombination steps; an S. cerevisiae-optimized TetR-VP16 activator; and a vector to integrate constructs into the yeast genome. We introduce into the S. cerevisiae genome the three crt genes from Erwinia herbicola required for yeast to synthesize lycopene and carry out the recombination process to produce a population of cells with permutations of tetO variants regulating the three genes. We identify 0.7% of this population as making detectable lycopene, of which the vast majority have undergone recombination at all three crt genes. We estimate a rate of ∼20% recombination per targeted site, much higher than that obtained in other studies. Application of this toolkit to medically or industrially important end products could reduce the time and labor required to optimize the expression of a set of metabolic genes.

  12. The role of the Saccharomyces cerevisiae lipoate protein ligase homologue, Lip3, in lipoic acid synthesis.

    Science.gov (United States)

    Hermes, Fatemah A; Cronan, John E

    2013-10-01

    The covalent attachment of lipoate to the lipoyl domains (LDs) of the central metabolism enzymes pyruvate dehydrogenase (PDH) and oxoglutarate dehydrogenase (OGDH) is essential for their activation and thus for respiratory growth in Saccharomyces cerevisiae. A third lipoate-dependent enzyme system, the glycine cleavage system (GCV), is required for utilization of glycine as a nitrogen source. Lipoate is synthesized by extraction of its precursor, octanoyl-acyl carrier protein (ACP), from the pool of fatty acid biosynthetic intermediates. Alternatively, lipoate is salvaged from previously modified proteins or from growth medium by lipoate protein ligases (Lpls). The first Lpl to be characterized, LplA of Escherichia coli, catalyses two partial reactions: activation of the acyl chain by formation of acyl-AMP, followed by transfer of the acyl chain to lipoyl domains (LDs). There is a surprising diversity within the Lpl family of enzymes, several of which catalyse reactions other than ligation reactions. For example, the Bacillus subtilis Lpl homologue LipM is an octanoyltransferase that transfers the octanoyl moiety from octanoyl-ACP to GCV. Another B. subtilis Lpl homologue, LipL, transfers octanoate from octanoyl-GCV to other LDs in an amido-transfer reaction. Study of eukaryotic Lpls has lagged behind studies of the bacterial enzymes. We report that the Lip3 Lpl homologue of the yeast S. cerevisiae has octanoyl-CoA-protein transferase activity, and discuss implications of this activity on the physiological role of Lip3 in lipoate synthesis. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  13. Pneumatosis Coli Mimicking Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Teresa Jacob

    2014-01-01

    Full Text Available Pneumatosis coli (PC is a rare condition of the gastrointestinal tract involving extraluminal gas confined within the bowel wall. We report the case of a 40-year-old gentleman presenting clinically and endoscopically with suspected colorectal cancer. In light of the patient’s red flag symptoms, and carpet of polyps seen endoscopically, surgical management by an anterior resection was performed with the patient making a successful recovery. Histological analysis of the resected specimen confirmed pneumatosis coli with no evidence of colonic neoplasia. Although PC can be an incidental finding in asymptomatic patients and considered a benign condition, it can also present as a life-threatening emergency with bowel necrosis and obstruction requiring emergency surgical intervention. Also, when PC mimics malignancy, surgical management is the most appropriate step to ensure that the diagnosis of cancer is not missed.

  14. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    OpenAIRE

    Toma, Claudia; Lu, Yan; Higa, Naomi; Nakasone, Noboru; Chinen, Isabel; Baschkier, Ariela; Rivas, Marta; Iwanaga, Masaaki

    2003-01-01

    A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.

  15. Non-introgressive genome chimerisation by malsegregation in autodiploidised allotetraploids during meiosis of Saccharomyces kudriavzevii x Saccharomyces uvarum hybrids.

    Science.gov (United States)

    Karanyicz, Edina; Antunovics, Zsuzsa; Kallai, Z; Sipiczki, M

    2017-06-01

    Saccharomyces strains with chimerical genomes consisting of mosaics of the genomes of different species ("natural hybrids") occur quite frequently among industrial and wine strains. The most widely endorsed hypothesis is that the mosaics are introgressions acquired via hybridisation and repeated backcrosses of the hybrids with one of the parental species. However, the interspecies hybrids are sterile, unable to mate with their parents. Here, we show by analysing synthetic Saccharomyces kudriavzevii x Saccharomyces uvarum hybrids that mosaic (chimeric) genomes can arise without introgressive backcrosses. These species are biologically separated by a double sterility barrier (sterility of allodiploids and F1 sterility of allotetraploids). F1 sterility is due to the diploidisation of the tetraploid meiosis resulting in MAT a /MAT α heterozygosity which suppresses mating in the spores. This barrier can occasionally be broken down by malsegregation of autosyndetically paired chromosomes carrying the MAT loci (loss of MAT heterozygosity). Subsequent malsegregation of additional autosyndetically paired chromosomes and occasional allosyndetic interactions chimerise the hybrid genome. Chromosomes are preferentially lost from the S. kudriavzevii subgenome. The uniparental transmission of the mitochondrial DNA to the hybrids indicates that nucleo-mitochondrial interactions might affect the direction of the genomic changes. We propose the name GARMe (Genome AutoReduction in Meiosis) for this process of genome reduction and chimerisation which involves no introgressive backcrossings. It opens a way to transfer genetic information between species and thus to get one step ahead after hybridisation in the production of yeast strains with beneficial combinations of properties of different species.

  16. Saccharomyces cerevisiae and non-Saccharomyces yeasts in grape varieties of the São Francisco Valley

    Directory of Open Access Journals (Sweden)

    Camila M.P.B.S. de Ponzzes-Gomes

    2014-06-01

    Full Text Available The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisiae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 x 10(5 cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production.

  17. The adenomatous polyposis coli protein.

    OpenAIRE

    Näthke, I S

    1999-01-01

    Mutations in the adenomatous polyposis coli (APC) gene are associated with most colorectal cancers. The APC protein has been implicated in many aspects of tumour development. This article will discuss recent data suggesting that APC may have multiple functions in the cell. First, APC is a component of the Wnt signalling pathway; second, APC may have a role in cell migration; finally, APC may regulate proliferation and apoptosis.

  18. Co-cultivation of non-conventional yeast with Saccharomyces cerevisiae to increase the aroma complexity of fermented beverages

    NARCIS (Netherlands)

    Rijswijck, van Irma M.H.

    2017-01-01

    Yeast are used as workhorses to convert hopped wort into beer. Conventionally, such yeasts belong to the genus Saccharomyces and most research on fermentation of wort for the production of beer has focussed on the species Saccharomyces cerevisiae and Saccharomyces

  19. 21 CFR 866.5785 - Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems.

    Science.gov (United States)

    2010-04-01

    ...) antibody (ASCA) test systems. 866.5785 Section 866.5785 Food and Drugs FOOD AND DRUG ADMINISTRATION... Immunological Test Systems § 866.5785 Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test systems. (a) Identification. The Anti-Saccharomyces cerevisiae (S. cerevisiae) antibody (ASCA) test system is...

  20. Saccharomyces jurei sp. nov., isolation and genetic identification of a novel yeast species from Quercus robur.

    Science.gov (United States)

    Naseeb, Samina; James, Stephen A; Alsammar, Haya; Michaels, Christopher J; Gini, Beatrice; Nueno-Palop, Carmen; Bond, Christopher J; McGhie, Henry; Roberts, Ian N; Delneri, Daniela

    2017-06-01

    Two strains, D5088T and D5095, representing a novel yeast species belonging to the genus Saccharomyces were isolated from oak tree bark and surrounding soil located at an altitude of 1000 m above sea level in Saint Auban, France. Sequence analyses of the internal transcribed spacer (ITS) region and 26S rRNA D1/D2 domains indicated that the two strains were most closely related to Saccharomyces mikatae and Saccharomyces paradoxus. Genetic hybridization analyses showed that both strains are reproductively isolated from all other Saccharomyces species and, therefore, represent a distinct biological species. The species name Saccharomyces jurei sp. nov. is proposed to accommodate these two strains, with D5088T (=CBS 14759T=NCYC 3947T) designated as the type strain.

  1. Construction of killer industrial yeast Saccharomyces cerevisiae HAU-1 and its fermentation performance

    Directory of Open Access Journals (Sweden)

    Bijender K. Bajaj

    2010-06-01

    Full Text Available Saccharomyces cerevisiae HAU-1, a time tested industrial yeast possesses most of the desirable fermentation characteristics like fast growth and fermentation rate, osmotolerance, high ethanol tolerance, ability to ferment molasses, and to ferment at elevated temperatures etc. However, this yeast was found to be sensitive against the killer strains of Saccharomyces cerevisiae. In the present study, killer trait was introduced into Saccharomyces cerevisiae HAU-1 by protoplast fusion with Saccharomyces cerevisiae MTCC 475, a killer strain. The resultant fusants were characterized for desirable fermentation characteristics. All the technologically important characteristics of distillery yeast Saccharomyces cerevisiae HAU-1 were retained in the fusants, and in addition the killer trait was also introduced into them. Further, the killer activity was found to be stably maintained during hostile conditions of ethanol fermentations in dextrose or molasses, and even during biomass recycling.

  2. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

    Science.gov (United States)

    2017-03-01

    Annual Surveillance Summary: Escherichia coli ( E . coli ) Infections in the Military Health System (MHS...or position of the Department of the Navy, Department of Defense, nor the U.S. Government. i i E . coli in the MHS: Annual Summary 2015 Prepared...March 2017 EpiData Center Department NMCPHC-EDC-TR-187-2017 ii ii E . coli in the MHS: Annual Summary 2015 Prepared March 2017 EpiData

  3. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    Science.gov (United States)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli .

  4. Mutational analysis of the RecJ exonuclease of Escherichia coli: identification of phosphoesterase motifs.

    Science.gov (United States)

    Sutera, V A; Han, E S; Rajman, L A; Lovett, S T

    1999-10-01

    The recJ gene, identified in Escherichia coli, encodes a Mg(+2)-dependent 5'-to-3' exonuclease with high specificity for single-strand DNA. Genetic and biochemical experiments implicate RecJ exonuclease in homologous recombination, base excision, and methyl-directed mismatch repair. Genes encoding proteins with strong similarities to RecJ have been found in every eubacterial genome sequenced to date, with the exception of Mycoplasma and Mycobacterium tuberculosis. Multiple genes encoding proteins similar to RecJ are found in some eubacteria, including Bacillus and Helicobacter, and in the archaea. Among this divergent set of sequences, seven conserved motifs emerge. We demonstrate here that amino acids within six of these motifs are essential for both the biochemical and genetic functions of E. coli RecJ. These motifs may define interactions with Mg(2+) ions or substrate DNA. A large family of proteins more distantly related to RecJ is present in archaea, eubacteria, and eukaryotes, including a hypothetical protein in the MgPa adhesin operon of Mycoplasma, a domain of putative polyA polymerases in Synechocystis and Aquifex, PRUNE of Drosophila, and an exopolyphosphatase (PPX1) of Saccharomyces cereviseae. Because these six RecJ motifs are shared between exonucleases and exopolyphosphatases, they may constitute an ancient phosphoesterase domain now found in all kingdoms of life.

  5. Hemolytic porcine intestinal Escherichia coli without virulence-associated genes typical of intestinal pathogenic E. coli.

    Science.gov (United States)

    Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

    2011-12-01

    Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli.

  6. Removal of Pyrimethanil and Fenhexamid from Saccharomyces cerevisiae Liquid Cultures

    Directory of Open Access Journals (Sweden)

    Etjen Bizaj

    2011-01-01

    Full Text Available The capacity for the removal of pyrimethanil and fenhexamid, two fungicides commonly used for the control of Botrytis cinerea in vineyards, has been evaluated during an alcoholic fermentation process in batch system. Commercial and wild strains of Saccharomyces cerevisiae were used. Batch fermentations were carried out in yeast extract-malt extract medium (YM with 18.0 % (by mass glucose, and the fungicides were added separately at three concentrations: 0.1, 1.0 and 10.0 mg/L. The removal capacity of yeast strains was also examined in stationary phase cultures of Saccharomyces cerevisiae. Stationary assays were performed with yeast biomass harvested from the stationary phase of an anaerobic fermentation process, with separate additions of 0.1, 1.0 and 10.0 mg/L of both fungicides. Removal studies with stationary phase cells were performed with viable and non-viable cells inactivated with sodium azide. This study clearly shows that both Saccharomyces cerevisiae strains were able to remove fenhexamid and pyrimethanil in stationary and fermentative assays. The removal potential is shown to be strain dependent in stationary but not in fermentative assays. However, the removal potential is dependent on the type of fungicide in both stationary and fermentative assays. In stationary phase cultures no significant difference in fungicide removal potential between viable and non-viable cells was observed, indicating that both pesticides were not degraded by metabolically active cells. However, the presence of both pesticides influenced fermentation kinetics and only pyrimethanil at 10.0 mg/L increased the production of volatile acidity of both strains.

  7. Protein expression of saccharomyces cerevisiae in response to uranium exposure

    International Nuclear Information System (INIS)

    Sakamoto, Fuminori; Nankawa, Takuya; Kozai, Naofumi; Ohnuki, Toshihiko; Fujii, Tsutomu; Iefuji, Haruyuki; Francis, A.J.

    2007-01-01

    Protein expression of Saccharomyces cerevisiae grown in the medium containing 238 U (VI) and 233 U (VI) was examined by two-dimensional gel electrophoresis. Saccharomyces cerevisiae of BY4743 was grown in yeast nitrogen base medium containing glucose and glycerol 2-phosphate and 238 U of 0, 2.0, and 5.0 x 10 -4 M or 233 U of 2.5 x 10 -6 M (radioactivity was higher by 350 times than 2.0 x 10 -4 M 238 U) and 5.0 x 10 -6 M for 112 h at 30 degC. The growth of Saccharomyces cerevisiae was monitored by measuring OD 600 at 112 h after the inoculation. Uranium concentrations in the media also were measured by radiometry using a liquid scintillation counter. The growths of the yeast grown in the above media were in the following order: control>2.5 x 10 -6 M 233 U>2.0 x 10 -4 M 238 U>5.0 x 10 -6 M 233 U>5.0 x 10 -4 M 238 U. This result indicated that not only radiological but also chemical effect of U reduced the growth of the yeast. The concentrations of U in the medium containing 238 U or 233 U decreased, suggesting U accumulation by the yeast cells. The 2-D gel electrophoresis analysis showed the appearance of several spots after exposure to 238 U or to 233 U but not in the control containing no uranium. These results show that the yeast cells exposed to U express several specific proteins. (author)

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

    Science.gov (United States)

    Johnson, Eric A

    2013-09-01

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

  9. Metabolic impact of redox cofactor perturbations in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hou, Jin; Lages, Nuno; Oldiges, M.

    2009-01-01

    to induce widespread changes in metabolism. We present a detailed analysis of the impact of perturbations in redox cofactors in the cytosol or mitochondria on glucose and energy metabolism in Saccharomyces cerevisiae to aid metabolic engineering decisions that involve cofactor engineering. We enhanced NADH...... oxidation by introducing NADH oxidase or alternative oxidase, its ATP-mediated conversion to NADPH using NADH kinase as well as the interconversion of NADH and NADPH independent of ATP by the soluble, non-proton-translocating bacterial transhydrogenase. Decreasing cytosolic NADH level lowered glycerol...

  10. Studies of the Saccharomyces cerevisiae Cultivation under Oscillatory Mixing Conditions

    Directory of Open Access Journals (Sweden)

    M?ris Rikmanis

    2005-12-01

    Full Text Available Saccharomyces cerevisiae was cultivated under non-aerated conditions in a 5 l laboratory bioreactor. Using the experimental data and the regression analysis method, some mathematical correlations for stirrer rotational speed oscillation frequency and the reaction of the yeast were established. It has been found that different growth parameters are influenced variously by stirrer rotational speed and stirrer rotational speed oscillation frequency. Stirring oscillations can be among the methods for stimulation of biotechnological processes. The obtained results can be used for designing bioreactors and optimizing working conditions.

  11. mRNA decapping enzyme from ribosomes of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stevens, A.

    1980-01-01

    By use of [ 3 H]methyl-5'-capped [ 14 C]mRNA from yeast as a substrate, a decapping enzyme activity has been detected in enzyme fractions derived from a high salt wash of ribosomes of Saccharomyces cerevisiae. The product of the decapping reaction is [ 3 H]m 7 GDP. That the enzyme is not a non-specific pyrophosphatase is suggested by the finding that the diphosphate product, m 7 GpppA(G), and UDP-glucose are not hydrolyzed

  12. Magnetically altered ethanol fermentation capacity of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Galonja-Corghill Tamara

    2009-01-01

    Full Text Available We studied the effect of static magnetic fields on ethanol production by yeast Saccharomyces cerevisiae 424A (LNH-ST using sugar cane molasses during the fermentation in an enclosed bioreactor. Two static NdFeB magnets were attached to a cylindrical tube reactor with their opposite poles (north to south, creating 150 mT magnetic field inside the reactor. Comparable differences emerged between the results of these two experimental conditions. We found ethanol productivity to be 15% higher in the samples exposed to 150 mT magnetic field.

  13. Pyruvate decarboxylases from the petite-negative yeast Saccharomyces kluyveri

    DEFF Research Database (Denmark)

    Møller, Kasper; Langkjær, Rikke Breinhold; Nielsen, Jens

    2004-01-01

    was controlled by variations in the amount of mRNA. The mRNA level and the pyruvate decarboxylase activity responded to anaerobiosis and growth on different carbon sources in essentially the same fashion as in S. cerevisiae. This indicates that the difference in ethanol formation between these two yeasts...... is not due to differences in the regulation of pyruvate decarboxylase(s), but rather to differences in the regulation of the TCA cycle and the respiratory machinery. However, the PDC genes of Saccharomyces/Kluyveromyces yeasts differ in their genetic organization and phylogenetic origin. While S. cerevisiae...

  14. How Saccharomyces cerevisiae copes with toxic metals and metalloids.

    Science.gov (United States)

    Wysocki, Robert; Tamás, Markus J

    2010-11-01

    Toxic metals and metalloids are widespread in nature and can locally reach fairly high concentrations. To ensure cellular protection and survival in such environments, all organisms possess systems to evade toxicity and acquire tolerance. This review provides an overview of the molecular mechanisms that contribute to metal toxicity, detoxification and tolerance acquisition in budding yeast Saccharomyces cerevisiae. We mainly focus on the metals/metalloids arsenic, cadmium, antimony, mercury, chromium and selenium, and emphasize recent findings on sensing and signalling mechanisms and on the regulation of tolerance and detoxification systems that safeguard cellular and genetic integrity.

  15. Enteroaggregative Escherichia coli in Daycare

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Stensvold, Christen R.; Struve, Carsten

    2016-01-01

    Enteroaggregative Escherichia coli (EAEC) has been associated with persistent diarrhea, reduced growth acceleration, and failure to thrive in children living in developing countries and with childhood diarrhea in general in industrialized countries. The clinical implications of an EAEC carrier...... and answered a questionnaire regarding gastrointestinal symptoms and exposures. Exposures included foreign travel, consumption of antibiotics, and contact with a diseased animal. In the capital area of Denmark, a total of 179 children aged 0-6 years were followed in a cohort study, in the period between 2009...

  16. Control of Saccharomyces cerevisiae catalase T gene (CTT1) expression by nutrient supply via the RAS-cyclic AMP pathway.

    Science.gov (United States)

    Bissinger, P H; Wieser, R; Hamilton, B; Ruis, H

    1989-03-01

    In Saccharomyces cerevisiae, lack of nutrients triggers a pleiotropic response characterized by accumulation of storage carbohydrates, early G1 arrest, and sporulation of a/alpha diploids. This response is thought to be mediated by RAS proteins, adenylate cyclase, and cyclic AMP (cAMP)-dependent protein kinases. This study shows that expression of the S. cerevisiae gene coding for a cytoplasmic catalase T (CTT1) is controlled by this pathway: it is regulated by the availability of nutrients. Lack of a nitrogen, sulfur, or phosphorus source causes a high-level expression of the gene. Studies with strains with mutations in the RAS-cAMP pathway and supplementation of a rca1 mutant with cAMP show that CTT1 expression is under negative control by a cAMP-dependent protein kinase and that nutrient control of CTT1 gene expression is mediated by this pathway. Strains containing a CTT1-Escherichia coli lacZ fusion gene have been used to isolate mutants with mutations in the pathway. Mutants characterized in this investigation fall into five complementation groups. Both cdc25 and ras2 alleles were identified among these mutants.

  17. Functional analysis of the stress response element and its role in the multistress response of Saccharomyces cerevisiae.

    Science.gov (United States)

    Treger, J M; Magee, T R; McEntee, K

    1998-02-04

    The DDR2 gene of Saccharomyces cerevisiae is a multistress response gene whose transcription is rapidly and strongly induced by a diverse array of xenobiotic agents, and environmental and physiological conditions. The multistress response of this gene requires the pentanucleotide, 5' CCCCT, (C4T;STRE (STress Response Element)) and the zinc-finger transcription factors, Msn2p and Msn4p. A 51bp oligonucleotide (oligo 31/32) containing two STREs from the DDR2 promoter region was previously shown to direct heat shock activation of a lacZ reporter gene. In this work we demonstrate that the same element conferred a complete multistress response to an E. coli galK reporter gene introduced into yeast cells. A variant oligonucleotide in which both the STRE spacing and neighboring sequences were altered responded to the same spectrum of stresses, while substitution of nucleotides within the pentanucleotide completely abolished the multistress response. These results directly demonstrate that STREs are not only necessary but are sufficient for mediating a transcriptional response to a surprisingly diverse set of environmental and physiological conditions.

  18. De Novo Biosynthesis of Glutarate via α-Keto Acid Carbon Chain Extension and Decarboxylation Pathway in Escherichia coli.

    Science.gov (United States)

    Wang, Jian; Wu, Yifei; Sun, Xinxiao; Yuan, Qipeng; Yan, Yajun

    2017-10-20

    Microbial based bioplastics are promising alternatives to petroleum based synthetic plastics due to their renewability and economic feasibility. Glutarate is one of the most potential building blocks for bioplastics. The recent biosynthetic routes for glutarate were mostly based on the l-lysine degradation pathway from Pseudomonas putida that required lysine either by feeding or lysine overproduction via genetic manipulations. Herein, we established a novel glutarate biosynthetic pathway by incorporation of a "+1" carbon chain extension pathway from α-ketoglutarate (α-KG) in combination with α-keto acid decarboxylation pathway in Escherichia coli. Introduction of homocitrate synthase (HCS), homoaconitase (HA) and homoisocitrate dehydrogenase (HICDH) from Saccharomyces cerevisiae into E. coli enabled "+1" carbon extension from α-KG to α-ketoadipate (α-KA), which was subsequently converted into glutarate by a promiscuous α-keto acid decarboxylase (KivD) and a succinate semialdehyde dehydrogenase (GabD). The recombinant E. coli coexpressing all five genes produced 0.3 g/L glutarate from glucose. To further improve the titers, α-KG was rechanneled into carbon chain extension pathway via the clustered regularly interspersed palindromic repeats system mediated interference (CRISPRi) of essential genes sucA and sucB in tricarboxylic acid (TCA) cycle. The final strain could produce 0.42 g/L glutarate, which was increased by 40% compared with the parental strain.

  19. The Eschericia coli Growth Inhibition Activity of Some Fermented Medicinal Plant Leaf Extract from the Karo Highland, North Sumatra

    Directory of Open Access Journals (Sweden)

    NOVIK NURHIDAYAT

    2009-10-01

    Full Text Available A lot of traditional medicinal plant has antibacterial acitivities. Most of these plants are freshly chewed or grounded and used directly to treat infectious bacterial deseases. However, some practices employ a traditionally spontaneous fermentation on boiled extracted leaf, root or other parts of the plant. This work reports a laboratory stimulated spontaneous fermentation of leaf extracts from selected medicinal plants collected from the Karo Higland. The spontaenous fermentation was stimulated to be carried out by the Acetobacter xylinum and Saccharomyces cerevisiae. The anti-infectious agent activity was assayed on the Eschericia coli growth inhibition. A complementary non fermented leaf extract was also made and assayed as a comparative measure. Indeed, the fermented leaf extract of bitter bush (Eupatorium pallescens, cacao (Theobroma cacao, avocado (Persia gratissima, passion fruit (Passiflora edulis, cassava (Cassava utillissima, diamond flower (Hedyotis corymbosa, periwinkle (Catharanthus roseus, and gandarusa (Justicia gendarussa have relatively higher anti-E.coli acitivity than those of non fermented ones. However, there were no anti-E.coli activity was detected in both fermented and non fermented leaf extract of the guava (Psidium guajava and common betel (Piper nigrum.

  20. Peptidoglycan Hydrolases of Escherichia coli

    Science.gov (United States)

    van Heijenoort, Jean

    2011-01-01

    Summary: The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. PMID:22126997

  1. ISOTERMAS DE ADSORÇÃO DE CÁDMIO POR Saccharomyces cerevisiae ISOTHERMS OF CADMIUM ADSORPTION BY Saccharomyces cerevisae

    Directory of Open Access Journals (Sweden)

    Silvana ALBERTINI

    2001-08-01

    Full Text Available Com o objetivo de determinar as isotermas de adsorção de cádmio por Saccharomyces cerevisiae, foram utilizados os sais cloreto e nitrato de cádmio nas concentrações de 5, 10, 20, 40, 60, 80 e 100mg L-1. A biomassa foi produzida a partir de uma cultura "starter"de Saccharomyces cerevisiae IZ 1904. Após o contato de 16h entre o microrganismo e as soluções em estudo, a biomassa foi separada por centrifugação e o teor de cádmio residual foi determinado no sobrenadante por espectrofotometria de absorção atômica. Para os dois sais empregados foi observado um acúmulo crescente de cádmio nas concentrações de 5, 10, 20 e 40mg L-1. Nas concentrações de 60, 80 e 100mg L-1 foi observado que a levedura acumulou teores menores do metal, evidenciando danos na parede celular, nem sempre acompanhados de iguais danos da membrana citoplasmática, tais alterações da parede visualizadas por microscopia eletrônica de varredura.With the objective of determining the isotherms of cadmium the adsorption by Saccharomyces cerevisiae, the chloride and nitrate salts were used in the concentrations of 5, 10, 20, 40, 60, 80, and 100mg L-1. The biomass was produced from a starter culture of Saccharomyces cerevisiae IZ 1904. After a 16h contact between the microrganism and solutions of study the biomass was separated by a centrifuge and the cadmium residue content was determined at the supernatant by atomic adsorption spectrophotometry. For the two salts used a growing accumulation of cadmium was observed at concentrations of 5, 10, 20, and 40mg L-1. In the concentrations of 60, 80 and 100mg L-1 a decreasing of the accumulation of the metal was observed, evidencing damages of the cellular wall, which they're not accompanied always by damages of the citoplasmatic membrane, visualized by scanning electron microscopy.

  2. Third International E. coli genome meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    Proceedings of the Third E. Coli Genome Meeting are provided. Presentations were divided into sessions entitled (1) Large Scale Sequencing, Sequence Analysis; (2) Databases; (3) Sequence Analysis; (4) Sequence Divergence in E. coli Strains; (5) Repeated Sequences and Regulatory Motifs; (6) Mutations, Rearrangements and Stress Responses; and (7) Origins of New Genes. The document provides a collection of abstracts of oral and poster presentations.

  3. Escherichia Coli Removal from Water Using Electrophotocatalytic ...

    African Journals Online (AJOL)

    Michael Horsfall

    inactivation of bacterial microorganisms in areas with low ... disinfection of water contaminated with fecal indicators such as E. coli ... media, brain heart infusion, sodium chloride, sodium hydroxide ... furnace at temperature 105 and 320°C f0r 60 min. For 2- and .... charge of E. coli logarithmic growth phase might affect the ...

  4. Antimicrobial resistance among commensal Escherichia coli from ...

    African Journals Online (AJOL)

    Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained from 382 samples.

  5. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra‑intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of ...

  6. Biochemical and serological characterization of Escherichia coli ...

    African Journals Online (AJOL)

    This study was designed to determine the isolation rate, serotypes and biochemical profiles of E. coli from colibacillosis and dead-in-shell embryos in Zaria, Northern-Nigeria. The isolation rate of E. coli from hatcheries studied were 4.67% and 7.50% from farms of Simtu Agricultural Company and National Animal Production ...

  7. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

  8. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA.

    Science.gov (United States)

    Alrowais, Hind; McElheny, Christi L; Spychala, Caressa N; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A; Doi, Yohei

    2015-11-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase-producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.

  9. Strategies for Protein Overproduction in Escherichia coli.

    Science.gov (United States)

    Mott, John E.

    1984-01-01

    Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

  10. Escherichia coli survival in waters: Temperature dependence

    Science.gov (United States)

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  11. Comparison of 61 Sequenced Escherichia coli Genomes

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Wassenaar, T. M.; Ussery, David

    2010-01-01

    Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...

  12. Antimicrobial resistance among commensal Escherichia coli from ...

    African Journals Online (AJOL)

    user1

    2012-07-19

    Jul 19, 2012 ... Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained.

  13. Fimbrial adhesins from extraintestinal Escherichia coli

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Schembri, Mark A.

    2010-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) represent an important subclass of E. coli that cause a wide spectrum of diseases in human and animal hosts. Fimbriae are key virulence factors of ExPEC strains. These long surface located rod-shaped organelles mediate receptor-specific attachment...

  14. lactamase in clinical isolates of Escherichia coli

    African Journals Online (AJOL)

    Jane

    2011-08-22

    Aug 22, 2011 ... The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems ... Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum ... difficulties in treatment using antibiotics that are currently ... and chloramphenicol (30 µg) (Mast Diagnostics Ltd., UK).

  15. Data on dynamic study of cytoophidia in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Hui Li

    2016-09-01

    Full Text Available The data in this paper are related to the research article entitled “Filamentation of metabolic enzymes in Saccharomyces cerevisiae” Q.J. Shen et al. (2016 [1]. Cytoophidia are filamentous structures discovered in fruit flies (doi:10.1016/S1673-8527(0960046-1 J.L. Liu (2010 [2], bacteria (doi:10.1038/ncb2087 M. Ingerson-Mahar et al. (2010 [3], yeast (doi:10.1083/jcb.201003001; doi:10.1242/bio.20149613 C. Noree et al. (2010 and J. Zhang, L. Hulme, J.L. Liu (2014 [4,5] and human cells (doi:10.1371/journal.pone.0029690; doi:10.1016/j.jgg.2011.08.004 K. Chen et al. (2011 and W.C. Carcamo et al. (2011 ( [6,7]. However, there is little research on the motility of the cytoophidia. Here we selected cytoophidia formed by 6 filament-forming proteins in the budding yeast S. cerevisiae, and performed living-cell imaging of cells expressing the proteins fused with GFP. The dynamic features of the six types of cytoophidia were analyzed. In the data, both raw movies and analysed results of the dynamics of cytoophidia are presented. Keywords: Saccharomyces cerevisiae, CTP synthase, Cytoophidium, Metabolism, Filamentation

  16. Omics analysis of acetic acid tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Geng, Peng; Zhang, Liang; Shi, Gui Yang

    2017-05-01

    Acetic acid is an inhibitor in industrial processes such as wine making and bioethanol production from cellulosic hydrolysate. It causes energy depletion, inhibition of metabolic enzyme activity, growth arrest and ethanol productivity losses in Saccharomyces cerevisiae. Therefore, understanding the mechanisms of the yeast responses to acetic acid stress is essential for improving acetic acid tolerance and ethanol production. Although 329 genes associated with acetic acid tolerance have been identified in the Saccharomyces genome and included in the database ( http://www.yeastgenome.org/observable/resistance_to_acetic_acid/overview ), the cellular mechanistic responses to acetic acid remain unclear in this organism. Post-genomic approaches such as transcriptomics, proteomics, metabolomics and chemogenomics are being applied to yeast and are providing insight into the mechanisms and interactions of genes, proteins and other components that together determine complex quantitative phenotypic traits such as acetic acid tolerance. This review focuses on these omics approaches in the response to acetic acid in S. cerevisiae. Additionally, several novel strains with improved acetic acid tolerance have been engineered by modifying key genes, and the application of these strains and recently acquired knowledge to industrial processes is also discussed.

  17. Characterization of an MMS sensitive mutant of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Martin, P.S.

    1979-01-01

    We have characterized a methyl methanesulfonate sensitive mutant of the yeast Saccharomyces cerevisiae in order to learn more about DNA repair and mutagenesis in this organism. The mutation, designated mms3-1, also confers sensitivity to ultraviolet light and to ethyl methanesulfonate in both haploids and homozygous diploids. Its effect on γ-ray sensitivity, however, is a function of the ploidy of the cell and its effect on induced mutation is a function of both the ploidy of the cell and the nature of the inducing agent. Our major findings are discussed. Our data indicate that: (1) Saccharomyces cerevisiae has an error prone pathway for the repair of uv damage controlled by the MMS3 gene product operating in and only in, and possibly induced by conditions present only in, a/α diploids; (2) in diploids, at least, there exists at least one step in the error prone repair of uv induced damage which is different from a step in the error prone repair of EMS induced damage; (3) a/α mms3-1/mms3-1 diploids may be defective in a step common to the repair of mutagenic lesions following uv irradiation and lethal lesions following γ irradiation; and (4) there are steps in the repair of MMS induced lethal damage that are different from steps in the repair of EMS induced lethal damage

  18. Mitochondrial introgression suggests extensive ancestral hybridization events among Saccharomyces species.

    Science.gov (United States)

    Peris, David; Arias, Armando; Orlić, Sandi; Belloch, Carmela; Pérez-Través, Laura; Querol, Amparo; Barrio, Eladio

    2017-03-01

    Horizontal gene transfer (HGT) in eukaryotic plastids and mitochondrial genomes is common, and plays an important role in organism evolution. In yeasts, recent mitochondrial HGT has been suggested between S. cerevisiae and S. paradoxus. However, few strains have been explored given the lack of accurate mitochondrial genome annotations. Mitochondrial genome sequences are important to understand how frequent these introgressions occur, and their role in cytonuclear incompatibilities and fitness. Indeed, most of the Bateson-Dobzhansky-Muller genetic incompatibilities described in yeasts are driven by cytonuclear incompatibilities. We herein explored the mitochondrial inheritance of several worldwide distributed wild Saccharomyces species and their hybrids isolated from different sources and geographic origins. We demonstrated the existence of several recombination points in mitochondrial region COX2-ORF1, likely mediated by either the activity of the protein encoded by the ORF1 (F-SceIII) gene, a free-standing homing endonuclease, or mostly facilitated by A+T tandem repeats and regions of integration of GC clusters. These introgressions were shown to occur among strains of the same species and among strains of different species, which suggests a complex model of Saccharomyces evolution that involves several ancestral hybridization events in wild environments. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Quality control of fifteen probiotic products containing Saccharomyces boulardii.

    Science.gov (United States)

    Vanhee, L M E; Goemé, F; Nelis, H J; Coenye, T

    2010-11-01

    The yeast Saccharomyces boulardii is used as a probiotic for the prevention and treatment of diarrhoea. In this study, the quality of 15 probiotic products containing S. boulardii was verified. Using microsatellite typing, the identity of all Saccharomyces strains in the products was confirmed as S. boulardii. Additionally, solid-phase cytometry (SPC) and a plate method were used to enumerate S. boulardii cells. SPC was not only able to produce results more rapidly than plating (4h compared to 48h) but the cell counts obtained with SPC were significantly higher than the plate counts. Finally, we found that boulardii cells survived 120min in gastric conditions and storage for 3months at 40°C with 75% relative humidity. We developed a SPC method for the quantification of viable S. boulardii cells in probiotics. Additionally, we demonstrated that gastric conditions and storage have a marked effect on the viability of the yeast cells.   To our knowledge, this is the first time SPC is used for the quality control of probiotics with S. boulardii. Additionally, we demonstrated the need for gastric protection and accurate storage. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

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

    Directory of Open Access Journals (Sweden)

    Zhang Tingting

    2012-12-01

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

  1. Functional Analysis of the FZF1 Genes of Saccharomyces uvarum

    Directory of Open Access Journals (Sweden)

    Xiaozhen Liu

    2018-02-01

    Full Text Available Being a sister species of Saccharomyces cerevisiae, Saccharomyces uvarum shows great potential regarding the future of the wine industry. The sulfite tolerance of most S. uvarum strains is poor, however. This is a major flaw that limits its utility in the wine industry. In S. cerevisiae, FZF1 plays a positive role in the transcription of SSU1, which encodes a sulfite efflux transport protein that is critical for sulfite tolerance. Although FZF1 has previously been shown to play a role in sulfite tolerance in S. uvarum, there is little information about its action mechanism. To assess the function of FZF1, two over-expression vectors that contained different FZF1 genes, and one FZF1 silencing vector, were constructed and introduced into a sulfite-tolerant S. uvarum strain using electroporation. In addition, an FZF1-deletion strain was constructed. Both of the FZF1-over-expressing strains showed an elevated tolerance to sulfite, and the FZF1-deletion strain showed the opposite effect. Repression of FZF1 transcription failed, however, presumably due to the lack of alleles of DCR1 and AGO. The qRT-PCR analysis was used to examine changes in transcription in the strains. Surprisingly, neither over-expressing strain promoted SSU1 transcription, although MET4 and HAL4 transcripts significantly increased in both sulfite-tolerance increased strains. We conclude that FZF1 plays a different role in the sulfite tolerance of S. uvarum compared to its role in S. cerevisiae.

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

    Science.gov (United States)

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

    2014-09-01

    The universal genetic code is used by all life forms to encode biological information. It can also be used to encrypt semantic messages and convey them within organisms without anyone but the sender and recipient knowing, i.e., as a means of steganography. Several theoretical, but comparatively few experimental, approaches have been dedicated to this subject, so far. Here, we describe an experimental system to stably integrate encrypted messages within the yeast genome using a polymerase chain reaction (PCR)-based, one-step homologous recombination system. Thus, DNA sequences encoding alphabetical and/or numerical information will be inherited by yeast propagation and can be sent in the form of dried yeast. Moreover, due to the availability of triple shuttle vectors, Saccharomyces cerevisiae can also be used as an intermediate construction device for transfer of information to either Drosophila or mammalian cells as steganographic containers. Besides its classical use in alcoholic fermentation and its modern use for heterologous gene expression, we here show that baker's yeast can thus be employed in a novel Saccharomyces application (NSA) as a simple steganographic container to hide and convey messages. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

  3. Non-Saccharomyces Yeasts Nitrogen Source Preferences: Impact on Sequential Fermentation and Wine Volatile Compounds Profile

    Science.gov (United States)

    Gobert, Antoine; Tourdot-Maréchal, Raphaëlle; Morge, Christophe; Sparrow, Céline; Liu, Youzhong; Quintanilla-Casas, Beatriz; Vichi, Stefania; Alexandre, Hervé

    2017-01-01

    Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN) deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non-Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non-Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With a view to improving the use of non-Saccharomyces yeasts in winemaking, we studied the use of amino acids and ammonium by three strains of non-Saccharomyces yeasts (Starmerella bacillaris, Metschnikowia pulcherrima, and Pichia membranifaciens) in grape juice. We first determined which nitrogen sources were preferentially used by these yeasts in pure cultures at 28 and 20°C (because few data are available). We then carried out sequential fermentations at 20°C with S. cerevisiae, to assess the impact of the non-Saccharomyces yeasts on the availability of assimilable nitrogen for S. cerevisiae. Finally, 22 volatile compounds were quantified in sequential fermentation and their levels compared with those in pure cultures of S. cerevisiae. We report here, for the first time, that non-Saccharomyces yeasts have specific amino-acid consumption profiles. Histidine, methionine, threonine, and tyrosine were not consumed by S. bacillaris, aspartic acid was assimilated very slowly by M. pulcherrima, and glutamine was not assimilated by P. membranifaciens. By contrast, cysteine appeared to be a preferred nitrogen source for all non-Saccharomyces yeasts. In sequential fermentation, these specific profiles of amino-acid consumption by non-Saccharomyces yeasts may account for some of the

  4. Non-Saccharomyces Yeasts Nitrogen Source Preferences: Impact on Sequential Fermentation and Wine Volatile Compounds Profile

    Directory of Open Access Journals (Sweden)

    Antoine Gobert

    2017-11-01

    Full Text Available Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non-Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non-Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With a view to improving the use of non-Saccharomyces yeasts in winemaking, we studied the use of amino acids and ammonium by three strains of non-Saccharomyces yeasts (Starmerella bacillaris, Metschnikowia pulcherrima, and Pichia membranifaciens in grape juice. We first determined which nitrogen sources were preferentially used by these yeasts in pure cultures at 28 and 20°C (because few data are available. We then carried out sequential fermentations at 20°C with S. cerevisiae, to assess the impact of the non-Saccharomyces yeasts on the availability of assimilable nitrogen for S. cerevisiae. Finally, 22 volatile compounds were quantified in sequential fermentation and their levels compared with those in pure cultures of S. cerevisiae. We report here, for the first time, that non-Saccharomyces yeasts have specific amino-acid consumption profiles. Histidine, methionine, threonine, and tyrosine were not consumed by S. bacillaris, aspartic acid was assimilated very slowly by M. pulcherrima, and glutamine was not assimilated by P. membranifaciens. By contrast, cysteine appeared to be a preferred nitrogen source for all non-Saccharomyces yeasts. In sequential fermentation, these specific profiles of amino-acid consumption by non-Saccharomyces yeasts may account for

  5. The adsorption of Sr(II) and Cs(I) ions by irradiated Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Yiming Tan; Jundong Feng; Liang Qiu; Zhentian Zhao; Xiaohong Zhang; Haiqian Zhang

    2017-01-01

    Adsorption behavior and mechanism of Sr(II) and Cs(I) in single and binary solutions using irradiated Saccharomyces cerevisiae was investigated. The effects of several environmental factors on Sr(II) and Cs(I) adsorption to irradiated Saccharomyces cerevisiae was determined. The equilibrium experimental data were simulated by different kinetic models and isotherm models. The combined effect of Sr(II) and Cs(I) on Saccharomyces cerevisiae is generally antagonistic. SEM and EDS analyses indicate that crystals formed on the cell surface are precipitate of Sr(II) and Cs(I), respectively. (author)

  6. Uranium removal from acidic aqueous solutions by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa

    International Nuclear Information System (INIS)

    Sarri, S.; Misaelides, P.; Papanikolaou, M.; Zamboulis, D.

    2009-01-01

    The sorption of uranium from acidic aqueous solutions (pH 4.5, C init = 10 to 1000 mg U/L) by Saccharomyces cerevisiae, Debaryomyces hansenii, Kluyveromyces marxianus and Candida colliculosa was investigated using a batch technique. The U-sorption onto Saccharomyces cerevisiae and Debaryomyces hansenii followed a Langmuir, while that onto Kluyveromyces marxianus and Candida colliculosa a Freundlich isotherm. The results demonstrated that all investigated biomasses could effectively remove uranium from acidic aqueous solutions. From all sorbents, Saccharomyces cerevisiae appeared to be the most effective with a maximum sorption capacity of 127.7 mg U/g dry biomass. (author)

  7. Bioethanol production by a flocculent hybrid, CHFY0321 obtained by protoplast fusion between Saccharomyces cerevisiae and Saccharomyces bayanus

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gi-Wook; Kang, Hyun-Woo; Kim, Yule [Changhae Institute of Cassava and Ethanol Research, Changhae Ethanol Co., LTD, Palbok-Dong 829, Dukjin-Gu, Jeonju 561-203 (Korea); Um, Hyun-Ju; Kim, Mina; Kim, Yang-Hoon [Department of Microbiology, Chungbuk National University, 410 Sungbong-Ro, Heungduk-Gu, Cheongju 361-763 (Korea)

    2010-08-15

    Fusion hybrid yeast, CHFY0321, was obtained by protoplast fusion between non-flocculent-high ethanol fermentative Saccharomyces cerevisiae CHY1011 and flocculent-low ethanol fermentative Saccharomyces bayanus KCCM12633. The hybrid yeast was used together with the parental strains to examine ethanol production in batch fermentation. Under the conditions tested, the fusion hybrid CHFY0321 flocculated to the highest degree and had the capacity to ferment well at pH 4.5 and 32 C. Simultaneous saccharification and fermentation for ethanol production was carried out using a cassava (Manihot esculenta) powder hydrolysate medium containing 19.5% (w v{sup -1}) total sugar in a 5 l lab scale jar fermenter at 32 C for 65 h with an agitation speed of 2 Hz. Under these conditions, CHFY0321 showed the highest flocculating ability and the best fermentation efficiency for ethanol production compared with those of the wild-type parent strains. CHFY0321 gave a final ethanol concentration of 89.8 {+-} 0.13 g l{sup -1}, a volumetric ethanol productivity of 1.38 {+-} 0.13 g l{sup -1} h{sup -1}, and a theoretical yield of 94.2 {+-} 1.58%. These results suggest that CHFY0321 exhibited the fermentation characteristics of S. cerevisiae CHY1011 and the flocculent ability of S. bayanus KCCM12633. Therefore, the strong highly flocculent ethanol fermentative CHFY0321 has potential for improving biotechnological ethanol fermentation processes. (author)

  8. Bioethanol production by a flocculent hybrid, CHFY0321 obtained by protoplast fusion between Saccharomyces cerevisiae and Saccharomyces bayanus

    International Nuclear Information System (INIS)

    Choi, Gi-Wook; Um, Hyun-Ju; Kang, Hyun-Woo; Kim, Yule; Kim, Mina; Kim, Yang-Hoon

    2010-01-01

    Fusion hybrid yeast, CHFY0321, was obtained by protoplast fusion between non-flocculent-high ethanol fermentative Saccharomyces cerevisiae CHY1011 and flocculent-low ethanol fermentative Saccharomyces bayanus KCCM12633. The hybrid yeast was used together with the parental strains to examine ethanol production in batch fermentation. Under the conditions tested, the fusion hybrid CHFY0321 flocculated to the highest degree and had the capacity to ferment well at pH 4.5 and 32 o C. Simultaneous saccharification and fermentation for ethanol production was carried out using a cassava (Manihot esculenta) powder hydrolysate medium containing 19.5% (w v -1 ) total sugar in a 5 l lab scale jar fermenter at 32 o C for 65 h with an agitation speed of 2 Hz. Under these conditions, CHFY0321 showed the highest flocculating ability and the best fermentation efficiency for ethanol production compared with those of the wild-type parent strains. CHFY0321 gave a final ethanol concentration of 89.8 ± 0.13 g l -1 , a volumetric ethanol productivity of 1.38 ± 0.13 g l -1 h -1 , and a theoretical yield of 94.2 ± 1.58%. These results suggest that CHFY0321 exhibited the fermentation characteristics of S. cerevisiae CHY1011 and the flocculent ability of S. bayanus KCCM12633. Therefore, the strong highly flocculent ethanol fermentative CHFY0321 has potential for improving biotechnological ethanol fermentation processes.

  9. Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis

    International Nuclear Information System (INIS)

    Andersson, R.; Schalen, C.; Tranberg, K.G.

    1991-01-01

    The effect of intraperitoneal bile on growth, peritoneal absorption, and clearance of Escherichia coli was determined in E coli peritonitis in the rat. In E coli peritonitis, intraperitoneal bacterial counts gradually decreased, whereas they increased (after 2 hours) with subsequent development of bacteremia in E coli plus bile peritonitis. After an intraperitoneal injection of labeled bacteria, blood radioactivity was only initially lower in E coli plus bile peritonitis compared with E coli peritonitis. Clearance from blood was lower in E coli plus bile peritonitis than in E coli peritonitis. Organ localization was similar in E coli peritonitis and E coli plus bile peritonitis with decreased splenic, increased pulmonary, and unchanged hepatic uptakes compared with controls. Impaired peritoneal absorption of bacteria, together with impaired local host defense, is likely to enhance the noxious effect of bile in E coli peritonitis

  10. Ubiquitin fusion constructs allow the expression and purification of multi-KOW domain complexes of the Saccharomyces cerevisiae transcription elongation factor Spt4/5.

    Science.gov (United States)

    Blythe, Amanda; Gunasekara, Sanjika; Walshe, James; Mackay, Joel P; Hartzog, Grant A; Vrielink, Alice

    2014-08-01

    Spt4/5 is a hetero-dimeric transcription elongation factor that can both inhibit and promote transcription elongation by RNA polymerase II (RNAPII). However, Spt4/5's mechanism of action remains elusive. Spt5 is an essential protein and the only universally-conserved RNAP-associated transcription elongation factor. The protein contains multiple Kyrpides, Ouzounis and Woese (KOW) domains. These domains, in other proteins, are thought to bind RNA although there is little direct evidence in the literature to support such a function in Spt5. This could be due, at least in part, to difficulties in expressing and purifying recombinant Spt5. When expressed in Escherichia coli (E. coli), Spt5 is innately insoluble. Here we report a new approach for the successful expression and purification of milligram quantities of three different multi-KOW domain complexes of Saccharomyces cerevisiae Spt4/5 for use in future functional studies. Using the E. coli strain Rosetta2 (DE3) we have developed strategies for co-expression of Spt4 and multi-KOW domain Spt5 complexes from the bi-cistronic pET-Duet vector. In a second strategy, Spt4/5 was expressed via co-transformation of Spt4 in the vector pET-M11 with Spt5 ubiquitin fusion constructs in the vector pHUE. We characterized the multi-KOW domain Spt4/5 complexes by Western blot, limited proteolysis, circular dichroism, SDS-PAGE and size exclusion chromatography-multiangle light scattering and found that the proteins are folded with a Spt4:Spt5 hetero-dimeric stoichiometry of 1:1. These expression constructs encompass a larger region of Spt5 than has previously been reported, and will provide the opportunity to elucidate the biological function of the multi-KOW containing Spt5. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra...

  12. Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes

    DEFF Research Database (Denmark)

    Albergaria, Helena; Arneborg, Nils

    2016-01-01

    Winemaking, brewing and baking are some of the oldest biotechnological processes. In all of them, alcoholic fermentation is the main biotransformation and Saccharomyces cerevisiae the primary microorganism. Although a wide variety of microbial species may participate in alcoholic fermentation and...

  13. Functional expression of a heterologous nickel-dependent, ATP-independent urease in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Milne, N.; Luttik, M.A.H.; Cueto Rojas, H.F.; Wahl, A.; Van Maris, A.J.A.; Pronk, J.T.; Daran, J.G.

    2015-01-01

    In microbial processes for production of proteins, biomass and nitrogen-containing commodity chemicals, ATP requirements for nitrogen assimilation affect product yields on the energy producing substrate. In Saccharomyces cerevisiae, a current host for heterologous protein production and potential

  14. Effect of menadione and hydrogen peroxide on catalase activity in Saccharomyces yeast strains

    Directory of Open Access Journals (Sweden)

    Nadejda EFREMOVA

    2013-05-01

    Full Text Available It has been studied the possibility of utilization of two important oxidant factors as regulators of catalase activity in Saccharomyces yeasts. In this paper results of the screening of some Saccharomyces yeast strains for potential producers of catalase are presented. Results of the screening for potential catalase producer have revealed that Saccharomyces cerevisiae CNMN-Y-11 strain possesses the highest catalase activity (2900 U/mg protein compared with other samples. Maximum increase of catalase activity with 50-60% compared to the reference sample was established in the case of hydrogen peroxide and menadione utilization in optimal concentrations of 15 and 10 mM. This research has been demonstrated the potential benefits of application of hydrogen peroxide and menadione as stimulatory factors of catalase activity in Saccharomyces yeasts.

  15. Evaluation of molecular typing techniques to assign genetic diversity among Saccharomyces cerevisiae strains

    NARCIS (Netherlands)

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

    1996-01-01

    Discrimination of strains within the species Saccharomyces cerevisiae was demonstrated by the use of four different techniques to type 15 strains isolated from spoiled wine and beer. Random amplified polymorphic DNA with specific oligonucleotides and PCR fingerprinting with the microsatellite

  16. Signature pathway expression of xylose utilization in the genetically engineered industrial yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Background: The limited xylose utilizing ability of native Saccharomyces cerevisiae has been a major obstacle for efficient cellulosic ethanol production from lignocellulosic materials. Haploid laboratory strains of S. cerevisiae are commonly used for genetic engineering to enable its xylose utiliza...

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  18. Multiplexed CRISPR/Cas9 Genome Editing and Gene Regulation Using Csy4 in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Ferreira, Raphael; Skrekas, Christos; Nielsen, Jens

    2018-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) technology has greatly accelerated the field of strain engineering. However, insufficient efforts have been made toward developing robust multiplexing tools in Saccharomyces cerevisiae. Here, we exploit the RNA processing capacity...

  19. Saccharomyces boulardii fungaemia in an intensive care unit patient treated with caspofungin

    Science.gov (United States)

    Lolis, Nikolaos; Veldekis, Dimitrios; Moraitou, Hellen; Kanavaki, Sofia; Velegraki, Aristea; Triandafyllidis, Charis; Tasioudis, Chronis; Pefanis, Angellos; Pneumatikos, Ioannis

    2008-01-01

    We describe a case of Saccharomyces boulardii fugaemia in a critically ill patient with septic shock treated with a probiotic agent containing this yeast. We attributed this fugaemia to gut translocation. Our use of caspofugin yielded excellent results. PMID:18423057

  20. Characterization of Magnaporthe oryzae chrysovirus 1 structural proteins and their expression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Urayama, Syunichi; Ohta, Tomoko; Onozuka, Nobuya; Sakoda, Hirofumi; Fukuhara, Toshiyuki; Arie, Tsutomu; Teraoka, Tohru; Moriyama, Hiromitsu

    2012-08-01

    Magnaporthe oryzae chrysovirus 1 (MoCV1), which is associated with an impaired growth phenotype of its host fungus, harbors four major proteins: P130 (130 kDa), P70 (70 kDa), P65 (65 kDa), and P58 (58 kDa). N-terminal sequence analysis of each protein revealed that P130 was encoded by double-stranded RNA1 (dsRNA1) (open reading frame 1 [ORF1] 1,127 amino acids [aa]), P70 by dsRNA4 (ORF4; 812 aa), and P58 by dsRNA3 (ORF3; 799 aa), although the molecular masses of P58 and P70 were significantly smaller than those deduced for ORF3 and ORF4, respectively. P65 was a degraded form of P70. Full-size proteins of ORF3 (84 kDa) and ORF4 (85 kDa) were produced in Escherichia coli. Antisera against these recombinant proteins detected full-size proteins encoded by ORF3 and ORF4 in mycelia cultured for 9, 15, and 28 days, and the antisera also detected smaller degraded proteins, namely, P58, P70, and P65, in mycelia cultured for 28 days. These full-size proteins and P58 and P70 were also components of viral particles, indicating that MoCV1 particles might have at least two forms during vegetative growth of the host fungus. Expression of the ORF4 protein in Saccharomyces cerevisiae resulted in cytological changes, with a large central vacuole associated with these growth defects. MoCV1 has five dsRNA segments, as do two Fusarium graminearum viruses (FgV-ch9 and FgV2), and forms a separate clade with FgV-ch9, FgV2, Aspergillus mycovirus 1816 (AsV1816), and Agaricus bisporus virus 1 (AbV1) in the Chrysoviridae family on the basis of their RdRp protein sequences.

  1. Survival of pathogenic Escherichia coli on basil, lettuce, and spinach

    Science.gov (United States)

    The contamination of lettuce, spinach and basil with pathogenic E. coli has caused numerous illnesses over the past decade. E. coli O157:H7, E. coli O104:H4 and avian pathogenic E. coli (APECstx- and APECstx+) were inoculated on basil plants and in promix soiless substrate using drip and overhead ir...

  2. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured...

  3. A scoping study on the prevalence of Escherichia coli and ...

    African Journals Online (AJOL)

    In the Eastern Cape Province E. coli and enterococci were detected in 7 and 4 of the 15 RHRW tanks, respectively. Enterococci were detected only from one river whereas E. coli was detected in all three rivers; in spring water neither enterococci nor E. coli were detected. Samples from GRWH tanks were positive for E. coli ...

  4. Increasing NADH oxidation reduces overflow metabolism in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Vemuri, Goutham; Eiteman, M.A; McEwen, J.E

    2007-01-01

    effect is due to limited respiratory capacity or is caused by glucose-mediated repression of respiration. When respiration in S. cerevisiae was increased by introducing a heterologous alternative oxidase, we observed reduced aerobic ethanol formation. In contrast, increasing nonrespiratory NADH oxidation...... Crabtree effect.’’ The yeast Saccharomyces cerevisiae has served as an important model organism for studying the Crabtree effect. When subjected to increasing glycolytic fluxes under aerobic conditions, there is a threshold value of the glucose uptake rate at which the metabolism shifts from purely...... respiratory to mixed respiratory and fermentative. It is well known that glucose repression of respiratory pathways occurs at high glycolytic fluxes, resulting in a decrease in respiratory capacity. Despite many years of detailed studies on this subject, it is not known whether the onset of the Crabtree...

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

    Science.gov (United States)

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

    2014-05-01

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

  6. Mechanisms and Regulation of Mitotic Recombination in Saccharomyces cerevisiae

    Science.gov (United States)

    Symington, Lorraine S.; Rothstein, Rodney; Lisby, Michael

    2014-01-01

    Homology-dependent exchange of genetic information between DNA molecules has a profound impact on the maintenance of genome integrity by facilitating error-free DNA repair, replication, and chromosome segregation during cell division as well as programmed cell developmental events. This chapter will focus on homologous mitotic recombination in budding yeast Saccharomyces cerevisiae. However, there is an important link between mitotic and meiotic recombination (covered in the forthcoming chapter by Hunter et al. 2015) and many of the functions are evolutionarily conserved. Here we will discuss several models that have been proposed to explain the mechanism of mitotic recombination, the genes and proteins involved in various pathways, the genetic and physical assays used to discover and study these genes, and the roles of many of these proteins inside the cell. PMID:25381364

  7. Metabolic engineering of Saccharomyces cerevisiae for overproduction of triacylglycerols

    DEFF Research Database (Denmark)

    Ferreira, Raphael; Teixeira, Paulo Goncalves; Gossing, Michael

    2018-01-01

    Triacylglycerols (TAGs) are valuable versatile compounds that can be used as metabolites for nutrition and health, as well as feedstocks for biofuel production. Although Saccharomyces cerevisiae is the favored microbial cell factory for industrial production of biochemicals, it does not produce...... large amounts of lipids and TAGs comprise only ~1% of its cell dry weight. Here, we engineered S. cerevisiae to reorient its metabolism for overproduction of TAGs, by regulating lipid droplet associated-proteins involved in TAG synthesis and hydrolysis. We implemented a push-and-pull strategy...... PXA1 led to accumulation of  254 mg∙gCDW−1. The TAG levels achieved here are the highest titer reported in S. cerevisiae, reaching 27.4% of the maximum theoretical yield in minimal medium with 2% glucose. This work shows the potential of using an industrially established and robust yeast species...

  8. Functional expression and evaluation of heterologous phosphoketolases in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Bergman, Alexandra; Siewers, Verena; Nielsen, Jens

    2016-01-01

    Phosphoketolases catalyze an energy-and redox-independent cleavage of certain sugar phosphates. Hereby, the two-carbon (C2) compound acetyl-phosphate is formed, which enzymatically can be converted into acetyl-CoA-a key precursor in central carbon metabolism. Saccharomyces cerevisiae does...... not demonstrate efficient phosphoketolase activity naturally. In this study, we aimed to compare and identify efficient heterologous phosphoketolase enzyme candidates that in yeast have the potential to reduce carbon loss compared to the native acetyl-CoA producing pathway by redirecting carbon flux directly from...... C5 and C6 sugars towards C2-synthesis. Nine phosphoketolase candidates were expressed in S. cerevisiae of which seven produced significant amounts of acetyl-phosphate after provision of sugar phosphate substrates in vitro. The candidates showed differing substrate specificities, and some...

  9. Radioimmunoassay for yeast killer toxin from Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Siddiqui, F.A.; Bussey, H.

    1981-01-01

    A radioimmunoassay was developed for the K1 killer toxin from strain T158C/S14a of Saccharomyces cerevisiae. Iodine 125-labelled toxin was made to a specific activity of 100 μCi/mg of protein. Antibody to purified toxin was prepared in rabbits using toxin cross-linked to itself. These antibodies, partially purified by 50 percent ammonium sulfate precipitation and Sepharose CL-6B column chromatography, produced one precipitation band with killer toxin and bound 125 I-labelled toxin in a radioimmunoassay. The antibody preparation also bound with the toxins from another K1 killer, A364A, and three chromosomal superkiller mutants derived from it. (auth)

  10. Division of labour in the yeast: Saccharomyces cerevisiae.

    Science.gov (United States)

    Wloch-Salamon, Dominika M; Fisher, Roberta M; Regenberg, Birgitte

    2017-10-01

    Division of labour between different specialized cell types is a central part of how we describe complexity in multicellular organisms. However, it is increasingly being recognized that division of labour also plays an important role in the lives of predominantly unicellular organisms. Saccharomyces cerevisiae displays several phenotypes that could be considered a division of labour, including quiescence, apoptosis and biofilm formation, but they have not been explicitly treated as such. We discuss each of these examples, using a definition of division of labour that involves phenotypic variation between cells within a population, cooperation between cells performing different tasks and maximization of the inclusive fitness of all cells involved. We then propose future research directions and possible experimental tests using S. cerevisiae as a model organism for understanding the genetic mechanisms and selective pressures that can lead to the evolution of the very first stages of a division of labour. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  11. Higher-order structure of Saccharomyces cerevisiae chromatin

    International Nuclear Information System (INIS)

    Lowary, P.T.; Widom, J.

    1989-01-01

    We have developed a method for partially purifying chromatin from Saccharomyces cerevisiae (baker's yeast) to a level suitable for studies of its higher-order folding. This has required the use of yeast strains that are free of the ubiquitous yeast killer virus. Results from dynamic light scattering, electron microscopy, and x-ray diffraction show that the yeast chromatin undergoes a cation-dependent folding into 30-nm filaments that resemble those characteristic of higher-cell chromatin; moreover, the packing of nucleosomes within the yeast 30-nm filaments is similar to that of higher cells. These results imply that yeast has a protein or protein domain that serves the role of the histone H 1 found in higher cells; physical and genetic studies of the yeast activity could help elucidate the structure and function of H 1. Images of the yeast 30-nm filaments can be used to test crossed-linker models for 30-nm filament structure

  12. Improvement of ethanol-tolerance of haploid Saccharomyces diastaticus

    International Nuclear Information System (INIS)

    Song, S.H.; Kim, K.; Lee, M.W.

    1994-01-01

    Several mutation procedures have been compared to obtain an ethanol-tolerant Saccharomyces diastaticus strain secreting glucoamylase. These procedures include spontaneous mutation, EMS treatment, UV irradiation, and combination of EMS treatment and UV irradiation. All these methods were followed by adaptation of the yeast cells to gradually higher ethanol concentration. Among these procedures, the combined method of EMS treatment and UV irradiation gave the promising result, i.e. the ethanol tolerance of the yeast increased from 11.5%(v/v) to 14.0%(v/v). Respiratory deficient petite mutants of industrial and ethanol-tolerant yeast strains have been isolated and hybridized with haploid S. diastaticus strains. The resulting hybrids showed increased ethanol tolerance and starch-fermentability

  13. Jeast (Saccharomyces cerevisial) mutants with enhanced induced mutagenesis

    International Nuclear Information System (INIS)

    Ivanov, E.L.; Koval'tsova, S.V.; Korolev, V.G.

    1987-01-01

    The influence of him1-1, him2-1, him3-1 and himX mutations on induction frequency and specificity of UV-induced adenine-dependent mutations in the yeast Saccharomyces cerevisiae has been. Him mutations do not render haploid cells more sensitive to the lethal action of UV-light; however, in him strains adeine-dependent mutations (ade, ade2) were induced more frequently (1.5-2-fold), as compared to the HIM strain. An analysis of the molecular nature of ade2 mutants revealed than him1-1, him2-1, and himX mutations increase specifically the yield of transitions (AT-GC and GC→AT), whereas in the him3-1, strain the yield of transversions was enhanced as well. We suggest him mutations analysed to affect specific repair pathway for mismatch correction

  14. Radiation induced formation of giant cells (Saccharomyces uvarum). Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Baumstark-Khan, C; Schnitzler, L; Rink, H

    1984-02-01

    X-irradiated yeast cells (Saccharomyces uvarum) grown in liquid media stop mitosis and form giant cells. Chitin ring formation, being a prerequisite for cell separation, was studied by fluorescence microscopy using Calcofluor White, a chitin specific dye. Experiments with inhibitors of DNA synthesis (hydroxyurea) and chitin synthesis (polyoxin D) demonstrate chitin ring formation to be dependent on DNA synthesis, whereas bud formation is independent of DNA synthesis and chitin ring formation respectively. Basing on these results the formation of X-ray induced giant cells implies one DNA replication which in turn induces the formation of only one chitin ring between mother cell and giant bud. Obviously no septum can be formed. Thus cell separation does not occur, but the bud already formed, produces another bud demonstrating that bud formation itself is independent of DNA synthesis.

  15. Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hou, Jin; Österlund, Tobias; Liu, Zihe

    2013-01-01

    The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often low due to limitations of the host strain. Heat shock response (HSR) is an inducible, global, cellular...... stress response, which facilitates the cell recovery from many forms of stress, e.g., heat stress. In S. cerevisiae, HSR is regulated mainly by the transcription factor heat shock factor (Hsf1p) and many of its targets are genes coding for molecular chaperones that promote protein folding and prevent...... the accumulation of mis-folded or aggregated proteins. In this work, we over-expressed a mutant HSF1 gene HSF1-R206S which can constitutively activate HSR, so the heat shock response was induced at different levels, and we studied the impact of HSR on heterologous protein secretion. We found that moderate and high...

  16. Interaction among Saccharomyces cerevisiae pheromone receptors during endocytosis

    Directory of Open Access Journals (Sweden)

    Chien-I Chang

    2014-03-01

    Full Text Available This study investigates endocytosis of Saccharomyces cerevisiae α-factor receptor and the role that receptor oligomerization plays in this process. α-factor receptor contains signal sequences in the cytoplasmic C-terminal domain that are essential for ligand-mediated endocytosis. In an endocytosis complementation assay, we found that oligomeric complexes of the receptor undergo ligand-mediated endocytosis when the α-factor binding site and the endocytosis signal sequences are located in different receptors. Both in vitro and in vivo assays suggested that ligand-induced conformational changes in one Ste2 subunit do not affect neighboring subunits. Therefore, recognition of the endocytosis signal sequence and recognition of the ligand-induced conformational change are likely to be two independent events.

  17. ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2014-02-01

    Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

  18. PROBİYOTİK MAYA : SACCHAROMYCES BOULARDİİ

    OpenAIRE

    Alkan, Rezan

    2013-01-01

    Probiyotikler uygun miktarlarda kullanıldığında konakçı sağlığı üzerinde yararları olan, bağırsakta canlı kalabilen ,sindirime dirençli bakteri ve maya gibi canlı mikroorganizmalar olarak tanımlanmaktadır. Saccharomyces boulardii  patojen olmayan bir maya olup, tedavi edici olarak kullanılmaktadır. Kontrollü olarak yapılan klinik çalışmalarda S.boulardii’nin çeşitli bağırsak hastalıklarının önlenmesi ve ...

  19. Energy-dependent effects of resveratrol in Saccharomyces cerevisiae.

    Science.gov (United States)

    Madrigal-Perez, Luis Alberto; Canizal-Garcia, Melina; González-Hernández, Juan Carlos; Reynoso-Camacho, Rosalia; Nava, Gerardo M; Ramos-Gomez, Minerva

    2016-06-01

    The metabolic effects induced by resveratrol have been associated mainly with the consumption of high-calorie diets; however, its effects with standard or low-calorie diets remain unclear. To better understand the interactions between resveratrol and cellular energy levels, we used Saccharomyces cerevisiae as a model. Herein it is shown that resveratrol: (a) decreased cell viability in an energy-dependent manner; (b) lessening of cell viability occurred specifically when cells were under cellular respiration; and (c) inhibition of oxygen consumption in state 4 occurred at low and standard energy levels, whereas at high energy levels oxygen consumption was promoted. These findings indicate that the effects of resveratrol are dependent on the cellular energy status and linked to metabolic respiration. Importantly, our study also revealed that S. cerevisiae is a suitable and useful model to elucidate the molecular targets of resveratrol under different nutritional statuses. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Radiation induced formation of giant cells (Saccharomyces uvarum). Pt. 1

    International Nuclear Information System (INIS)

    Baumstark-Khan, C.; Schnitzler, L.; Rink, H.

    1984-01-01

    X-irradiated yeast cells (Saccharomyces uvarum) grown in liquid media stop mitosis and form giant cells. Chitin ring formation, being a prerequisite for cell separation, was studied by fluorescence microscopy using Calcofluor White, a chitin specific dye. Experiments with inhibitors of DNA synthesis (hydroxyurea) and chitin synthesis (polyoxin D) demonstrate chitin ring formation to be dependent on DNA synthesis, whereas bud formation is independent of DNA synthesis and chitin ring formation respectively. Basing on these results the formation of X-ray induced giant cells implies one DNA replication which in turn induces the formation of only one chitin ring between mother cell and giant bud. Obviously no septum can be formed. Thus cell separation does not occur, but the bud already formed, produces another bud demonstrating that bud formation itself is independent of DNA synthesis. (orig.)

  1. Properties of promoters cloned randomly from the Saccharomyces cerevisiae genome.

    Science.gov (United States)

    Santangelo, G M; Tornow, J; McLaughlin, C S; Moldave, K

    1988-01-01

    Promoters were isolated at random from the genome of Saccharomyces cerevisiae by using a plasmid that contains a divergently arrayed pair of promoterless reporter genes. A comprehensive library was constructed by inserting random (DNase I-generated) fragments into the intergenic region upstream from the reporter genes. Simple in vivo assays for either reporter gene product (alcohol dehydrogenase or beta-galactosidase) allowed the rapid identification of promoters from among these random fragments. Poly(dA-dT) homopolymer tracts were present in three of five randomly cloned promoters. With two exceptions, each RNA start site detected was 40 to 100 base pairs downstream from a TATA element. All of the randomly cloned promoters were capable of activating reporter gene transcription bidirectionally. Interestingly, one of the promoter fragments originated in a region of the S. cerevisiae rDNA spacer; regulated divergent transcription (presumably by RNA polymerase II) initiated in the same region. Images PMID:2847031

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

    Science.gov (United States)

    Marsit, Souhir; Dequin, Sylvie

    2015-01-01

    Saccharomyces cerevisiae and related species, the main workhorses of wine fermentation, have been exposed to stressful conditions for millennia, potentially resulting in adaptive differentiation. As a result, wine yeasts have recently attracted considerable interest for studying the evolutionary effects of domestication. The widespread use of whole-genome sequencing during the last decade has provided new insights into the biodiversity, population structure, phylogeography and evolutionary history of wine yeasts. Comparisons between S. cerevisiae isolates from various origins have indicated that a variety of mechanisms, including heterozygosity, nucleotide and structural variations, introgressions, horizontal gene transfer and hybridization, contribute to the genetic and phenotypic diversity of S. cerevisiae. This review will summarize the current knowledge on the diversity and evolutionary history of wine yeasts, focusing on the domestication fingerprints identified in these strains. PMID:26205244

  3. Repair of UV-damaged incoming plasmid DNA in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Keszenman-Pereyra, David

    1990-01-01

    A whole-cell transformation assay was used for the repair of UV-damaged plasma DNA in highly-transformable haploid strains of Saccharomyces cerevisiae having different repair capabilities. The experiments described demonstrate that three epistasis groups (Friedberg 1988) are involved in the repair of UV-incoming DNA and that the repair processes act less efficiently on incoming DNA than they do on chromosomal DNA. The implications of these findings for UV repair in Saccharomyces cerevisiae are discussed. (author)

  4. Anaerobic organic acid metabolism of Candida zemplinina in comparison with Saccharomyces wine yeasts.

    Science.gov (United States)

    Magyar, Ildikó; Nyitrai-Sárdy, Diána; Leskó, Annamária; Pomázi, Andrea; Kállay, Miklós

    2014-05-16

    Organic acid production under oxygen-limited conditions has been thoroughly studied in the Saccharomyces species, but practically never investigated in Candida zemplinina, which seems to be an acidogenic species under oxidative laboratory conditions. In this study, several strains of C. zemplinina were tested for organic acid metabolism, in comparison with Saccharomyces cerevisiae, Saccharomyces uvarum and Candida stellata, under fermentative conditions. Only C. stellata produced significantly higher acidity in simple minimal media (SM) with low sugar content and two different nitrogen sources (ammonia or glutamic acid) at low level. However, the acid profile differed largely between the Saccharomyces and Candida species and showed inverse types of N-dependence in some cases. Succinic acid production was strongly enhanced on glutamic acid in Saccharomyces species, but not in Candida species. 2-oxoglutarate production was strongly supported on ammonium nitrogen in Candida species, but remained low in Saccharomyces. Candida species, C. stellata in particular, produced more pyruvic acid regardless of N-sources. From the results, we concluded that the anaerobic organic acid metabolisms of C. zemplinina and C. stellata are different from each other and also from that of the Saccharomyces species. In the formation of succinic acid, the oxidative pathway from glutamic acid seems to play little or no role in C. zemplinina. The reductive branch of the TCA cycle, however, produces acidic intermediates (malic, fumaric, and succinic acid) in a level comparable with the production of the Saccharomyces species. An unidentified organic acid, which was produced on glutamic acid only by the Candida species, needs further investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Large-scale functional genomic analysis of sporulation and meiosis in Saccharomyces cerevisiae.

    OpenAIRE

    Enyenihi, Akon H; Saunders, William S

    2003-01-01

    We have used a single-gene deletion mutant bank to identify the genes required for meiosis and sporulation among 4323 nonessential Saccharomyces cerevisiae annotated open reading frames (ORFs). Three hundred thirty-four sporulation-essential genes were identified, including 78 novel ORFs and 115 known genes without previously described sporulation defects in the comprehensive Saccharomyces Genome (SGD) or Yeast Proteome (YPD) phenotype databases. We have further divided the uncharacterized sp...

  6. Global mapping of DNA conformational flexibility on Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Giulia Menconi

    2015-04-01

    Full Text Available In this study we provide the first comprehensive map of DNA conformational flexibility in Saccharomyces cerevisiae complete genome. Flexibility plays a key role in DNA supercoiling and DNA/protein binding, regulating DNA transcription, replication or repair. Specific interest in flexibility analysis concerns its relationship with human genome instability. Enrichment in flexible sequences has been detected in unstable regions of human genome defined fragile sites, where genes map and carry frequent deletions and rearrangements in cancer. Flexible sequences have been suggested to be the determinants of fragile gene proneness to breakage; however, their actual role and properties remain elusive. Our in silico analysis carried out genome-wide via the StabFlex algorithm, shows the conserved presence of highly flexible regions in budding yeast genome as well as in genomes of other Saccharomyces sensu stricto species. Flexibile peaks in S. cerevisiae identify 175 ORFs mapping on their 3'UTR, a region affecting mRNA translation, localization and stability. (TAn repeats of different extension shape the central structure of peaks and co-localize with polyadenylation efficiency element (EE signals. ORFs with flexible peaks share common features. Transcripts are characterized by decreased half-life: this is considered peculiar of genes involved in regulatory systems with high turnover; consistently, their function affects biological processes such as cell cycle regulation or stress response. Our findings support the functional importance of flexibility peaks, suggesting that the flexible sequence may be derived by an expansion of canonical TAYRTA polyadenylation efficiency element. The flexible (TAn repeat amplification could be the outcome of an evolutionary neofunctionalization leading to a differential 3'-end processing and expression regulation in genes with peculiar function. Our study provides a new support to the functional role of flexibility in

  7. Global mapping of DNA conformational flexibility on Saccharomyces cerevisiae.

    Science.gov (United States)

    Menconi, Giulia; Bedini, Andrea; Barale, Roberto; Sbrana, Isabella

    2015-04-01

    In this study we provide the first comprehensive map of DNA conformational flexibility in Saccharomyces cerevisiae complete genome. Flexibility plays a key role in DNA supercoiling and DNA/protein binding, regulating DNA transcription, replication or repair. Specific interest in flexibility analysis concerns its relationship with human genome instability. Enrichment in flexible sequences has been detected in unstable regions of human genome defined fragile sites, where genes map and carry frequent deletions and rearrangements in cancer. Flexible sequences have been suggested to be the determinants of fragile gene proneness to breakage; however, their actual role and properties remain elusive. Our in silico analysis carried out genome-wide via the StabFlex algorithm, shows the conserved presence of highly flexible regions in budding yeast genome as well as in genomes of other Saccharomyces sensu stricto species. Flexibile peaks in S. cerevisiae identify 175 ORFs mapping on their 3'UTR, a region affecting mRNA translation, localization and stability. (TA)n repeats of different extension shape the central structure of peaks and co-localize with polyadenylation efficiency element (EE) signals. ORFs with flexible peaks share common features. Transcripts are characterized by decreased half-life: this is considered peculiar of genes involved in regulatory systems with high turnover; consistently, their function affects biological processes such as cell cycle regulation or stress response. Our findings support the functional importance of flexibility peaks, suggesting that the flexible sequence may be derived by an expansion of canonical TAYRTA polyadenylation efficiency element. The flexible (TA)n repeat amplification could be the outcome of an evolutionary neofunctionalization leading to a differential 3'-end processing and expression regulation in genes with peculiar function. Our study provides a new support to the functional role of flexibility in genomes and a

  8. Phenotypic characterisation of Saccharomyces spp. for tolerance to 1-butanol.

    Science.gov (United States)

    Zaki, A M; Wimalasena, T T; Greetham, D

    2014-11-01

    Biofuels are expected to play a role in replacing crude oil as a liquid transportation fuel, and research into butanol has highlighted the importance of this alcohol as a fuel. Butanol has a higher energy density than ethanol, butanol-gasoline blends do not separate in the presence of water, and butanol is miscible with gasoline (Szulczyk, Int J Energy Environ 1(1):2876-2895, 40). Saccharomyces cerevisiae has been used as a fermentative organism in the biofuel industry producing ethanol from glucose derived from starchy plant material; however, it typically cannot tolerate butanol concentrations greater than 2 % (Luong, Biotechnol Bioeng 29 (2):242-248, 27). 90 Saccharomyces spp. strains were screened for tolerance to 1-butanol via a phenotypic microarray assay and we observed significant variation in response with the most tolerant strains (S. cerevisiae DBVPG1788, S. cerevisiae DBVPG6044 and S. cerevisiae YPS128) exhibiting tolerance to 4 % 1-butanol compared with S. uvarum and S. castelli strains, which were sensitive to 3 % 1-butanol. Response to butanol was confirmed using traditional yeast methodologies such as growth; it was observed that fermentations in the presence of butanol, when using strains with a tolerant background, were significantly faster. Assessing for genetic rationale for tolerance, it was observed that 1-butanol-tolerant strains, when compared with 1-butanol-sensitive strains, had an up-regulation of RPN4, a transcription factor which regulates proteasome genes. Analysing for the importance of RPN4, we observed that a Δrpn4 strain displayed a reduced rate of fermentation in the presence of 1-butanol when compared with the BY4741 background strain. This data will aid the development of breeding programmes to produce better strains for future bio-butanol production.

  9. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation

    Science.gov (United States)

    Liu, Ling-ling; Jia, Bo; Zhao, Fang; Huang, Wei-dong; Zhan, Ji-cheng

    2015-01-01

    At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo) and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China’s stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress. PMID:26030864

  10. Copper Tolerance and Biosorption of Saccharomyces cerevisiae during Alcoholic Fermentation.

    Directory of Open Access Journals (Sweden)

    Xiang-Yu Sun

    Full Text Available At high levels, copper in grape mash can inhibit yeast activity and cause stuck fermentations. Wine yeast has limited tolerance of copper and can reduce copper levels in wine during fermentation. This study aimed to understand copper tolerance of wine yeast and establish the mechanism by which yeast decreases copper in the must during fermentation. Three strains of Saccharomyces cerevisiae (lab selected strain BH8 and industrial strains AWRI R2 and Freddo and a simple model fermentation system containing 0 to 1.50 mM Cu2+ were used. ICP-AES determined Cu ion concentration in the must decreasing differently by strains and initial copper levels during fermentation. Fermentation performance was heavily inhibited under copper stress, paralleled a decrease in viable cell numbers. Strain BH8 showed higher copper-tolerance than strain AWRI R2 and higher adsorption than Freddo. Yeast cell surface depression and intracellular structure deformation after copper treatment were observed by scanning electron microscopy and transmission electron microscopy; electronic differential system detected higher surface Cu and no intracellular Cu on 1.50 mM copper treated yeast cells. It is most probably that surface adsorption dominated the biosorption process of Cu2+ for strain BH8, with saturation being accomplished in 24 h. This study demonstrated that Saccharomyces cerevisiae strain BH8 has good tolerance and adsorption of Cu, and reduces Cu2+ concentrations during fermentation in simple model system mainly through surface adsorption. The results indicate that the strain selected from China's stress-tolerant wine grape is copper tolerant and can reduce copper in must when fermenting in a copper rich simple model system, and provided information for studies on mechanisms of heavy metal stress.

  11. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    Science.gov (United States)

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-13

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  12. Evidence for Divergent Evolution of Growth Temperature Preference in Sympatric Saccharomyces Species

    Science.gov (United States)

    Gonçalves, Paula; Valério, Elisabete; Correia, Cláudia; de Almeida, João M. G. C. F.; Sampaio, José Paulo

    2011-01-01

    The genus Saccharomyces currently includes eight species in addition to the model yeast Saccharomyces cerevisiae, most of which can be consistently isolated from tree bark and soil. We recently found sympatric pairs of Saccharomyces species, composed of one cryotolerant and one thermotolerant species in oak bark samples of various geographic origins. In order to contribute to explain the occurrence in sympatry of Saccharomyces species, we screened Saccharomyces genomic data for protein divergence that might be correlated to distinct growth temperature preferences of the species, using the dN/dS ratio as a measure of protein evolution rates and pair-wise species comparisons. In addition to proteins previously implicated in growth at suboptimal temperatures, we found that glycolytic enzymes were among the proteins exhibiting higher than expected divergence when one cryotolerant and one thermotolerant species are compared. By measuring glycolytic fluxes and glycolytic enzymatic activities in different species and at different temperatures, we subsequently show that the unusual divergence of glycolytic genes may be related to divergent evolution of the glycolytic pathway aligning its performance to the growth temperature profiles of the different species. In general, our results support the view that growth temperature preference is a trait that may have undergone divergent selection in the course of ecological speciation in Saccharomyces. PMID:21674061

  13. Inheritance and organisation of the mitochondrial genome differ between two Saccharomyces yeasts

    DEFF Research Database (Denmark)

    Petersen, Randi Føns; Langkjær, Rikke Breinhold; Hvidtfeldt, J.

    2002-01-01

    Petite-positive Saccharomyces yeasts can be roughly divided into the sensu stricto, including Saccharomyces cerevisiae, and sensu lato group, including Saccharomyces castellii; the latter was recently studied for transmission and the organisation of its mitochondrial genome. S. castellii mitochon......Petite-positive Saccharomyces yeasts can be roughly divided into the sensu stricto, including Saccharomyces cerevisiae, and sensu lato group, including Saccharomyces castellii; the latter was recently studied for transmission and the organisation of its mitochondrial genome. S. castellii...... mitochondrial molecules (mtDNA) carrying point mutations, which confer antibiotic resistance, behaved in genetic crosses as the corresponding point mutants of S. cerevisiae. While S. castellii generated spontaneous petite mutants in a similar way as S. cerevisiae, the petites exhibited a different inheritance...... pattern. In crosses with the wild type strains a majority of S. castellii petites was neutral, and the suppressivity in suppressive petites was never over 50%. The two yeasts also differ in organisation of their mtDNA molecules. The 25,753 bp sequence of S. castellii mtDNA was determined and the coding...

  14. PRODUKSI ETANOL DARI TETES TEBU OLEH Saccharomyces cerevisiae PEMBENTUK FLOK (NRRL – Y 265 (Ethanol Production from Cane Molasses by Flocculant Saccharomyces cerevisiae (NRRL – Y 265

    Directory of Open Access Journals (Sweden)

    Agustin Krisna Wardani

    2013-08-01

    Full Text Available The potential use of sugar cane molasses by flocculant Saccharomyces cerevisiae in ethanol production was investigated. In order to minimize the negative effect of calcium on yeast growth, pretreated sugar cane molasses with dilute acid was performed. The influence of process parameters such as sugar concentration and inoculum concentration were evaluated for enhancing bioethanol production. Result showed that maximum ethanol concentration of 8,792% (b/v was obtained at the best condition of inoculum concentration 10% (v/v and sugar concentration 15% (b/v. Based on the experimental data, maximum yield of ethanol production of 65% was obtained. This result demonstrated the potential of molasses as promising biomass resources for ethanol production. Keywords: Ethanol, preteated cane molasses, flocculant Saccharomyces cerevisiae, fermentation   ABSTRAK Efisiensi produksi bioetanol diperoleh melalui ketepatan pemilihan jenis mikroorganisme, bahan baku, dan kontrol proses fermentasi. Alternatif proses untuk meminimalisasi biaya produksi etanol adalah dengan mengeliminasi tahap pemisahan sentrifugasi sel dari produk karena memerlukan biaya instalasi dan biaya perawatan yang tinggi. Proses sentrifugasi merupakan tahapan penting untuk memisahkan sel mikroba dari medium fermentasi pada produksi bioetanol. Untuk meminimalisir biaya produksi akibat proses tersebut digunakan inokulum Saccharomyces cerevisiae pembentuk flok dan tetes tebu sebagai sumber gula. Penelitian ini bertujuan untuk mendapatkan konsentrasi penambahan inokulum Saccharomyces cerevisiae pembentuk flok dan konsentrasi sumber gula dalam tetes tebu yang tepat dalam produksi etanol yang maksimum. Saccharomyces cerevisiae sebanyak 5%, 10%, dan 15% (v/v diinokulasikan pada medium tetes tebu hasil pretreatment dengan kandungan gula 15%, 20%, dan 25% (b/v pada pH 5. Fermentasi dilakukan pada suhu 30°C dan agitasi 100 rpm selama 72 jam. Etanol tertinggi didapat pada kondisi konsentrasi inokulum

  15. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... the most common serious bacterial infections in infants ... UTI is a common cause of morbidity .... of ESBL and non-ESBL producing Escherichia coli and Klebsiella pneumonia. ... in hospital and community acquired infections.

  16. FTIR nanobiosensors for Escherichia coli detection

    Directory of Open Access Journals (Sweden)

    Stefania Mura

    2012-07-01

    Full Text Available Infections due to enterohaemorrhagic E. coli (Escherichia coli have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyltriethoxysilane and GA (glutaraldehyde were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples.

  17. Escherichia coli pyomyositis in an immunocompromised host.

    Science.gov (United States)

    Sharma, Umesh; Schwan, William R; Agger, William A

    2011-08-01

    Pyomyositis due to Escherichia coli (E. coil) is rarely reported in immunocompromised patients with hematological malignancy. We present a case report of a 34-year-old man who developed E. coli pyomyositis as a complication of acute myelogenous leukemia (AML). Magnetic resonance imaging (MRI) of the right hip suggested myofascial infection of the gluteal muscles, and a needle muscle aspiration grew E. coli phylogenetic group B2. The patient responded to intravenous piperacillin/tazobactam followed by prolonged oral levofloxacin. Pyomyositis should be suspected in all immunocompromised patients complaining of muscle pain and may exhibit signs of localized muscle infection. Appropriate antibiotic therapy targeting fluoroquinolone-resistant E. coli should be considered for initial empiric therapy of pyomyositis in immunocompromised patients.

  18. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    tract infection (UTI), bacteremia, pneumonia, soft-tissue infection, and ... Keywords: Drug resistance, Escherichia coli, Extraintestinal infections, Polymerase chain reaction, .... gynecology, 12 from orthopedics and 5 from pediatrics units.

  19. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra......-intestinal pathogenic E. coli (ExPEC) are able to colonize tissue outside the gastrointestinal tract and contain a variety of virulence factors that may enable the pathogens to invade and induce infections in the cardiac endothelia. In these cases echocardiography as the imaging technology is of paramount importance...

  20. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Reisner, A.; Holler, B.M.; Molin, Søren

    2006-01-01

    Bacterial biofilms, often composed of multiple species and genetically distinct strains, develop under complex influences of cell-cell interactions. Although detailed knowledge about the mechanisms underlying formation of single-species laboratory biofilms has emerged, little is known about...... the pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...... the cocultivation of 403 undomesticated E. coli strains with a characterized E. coli K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of E. coli isolates (n = 56) exhibiting...

  1. Experimental induced avian E. coli salpingitis

    DEFF Research Database (Denmark)

    Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth

    2016-01-01

    Several types of Escherichia coli have been associated with extra-intestinal infections in poultry, however, they may vary significantly in their virulence potential. The aim of the present study was to investigate the virulence of five strains of E. coli obtained from different disease......) had a distinct ability to cause disease. Results of the study shows major differences in virulence of different strains of E. coli in ascending infections; however, there was no indication of tissue-specific adaptation, since strains obtained from lesions unrelated to the reproductive system were...... fully capable of causing experimental infection. In conclusion, the study provides evidence for the clinical outcome of infection with E. coli in poultry is largely influenced by the specific strain as well as individual host factors....

  2. ECMDB: The E. coli Metabolome Database

    OpenAIRE

    Guo, An Chi; Jewison, Timothy; Wilson, Michael; Liu, Yifeng; Knox, Craig; Djoumbou, Yannick; Lo, Patrick; Mandal, Rupasri; Krishnamurthy, Ram; Wishart, David S.

    2012-01-01

    The Escherichia coli Metabolome Database (ECMDB, http://www.ecmdb.ca) is a comprehensively annotated metabolomic database containing detailed information about the metabolome of E. coli (K-12). Modelled closely on the Human and Yeast Metabolome Databases, the ECMDB contains >2600 metabolites with links to ?1500 different genes and proteins, including enzymes and transporters. The information in the ECMDB has been collected from dozens of textbooks, journal articles and electronic databases. E...

  3. Co-cultivation of non-conventional yeast with Saccharomyces cerevisiae to increase the aroma complexity of fermented beverages

    OpenAIRE

    Rijswijck, van, Irma M.H.

    2017-01-01

    Yeast are used as workhorses to convert hopped wort into beer. Conventionally, such yeasts belong to the genus Saccharomyces and most research on fermentation of wort for the production of beer has focussed on the species Saccharomyces cerevisiae and Saccharomyces pastorianus. Recently, there is an increasing interest in unravelling features of non-conventional yeast species for beer innovation. In this thesis, features of yeast isolates belonging to the species: Cyberlindnera fabianii, Pichi...

  4. Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae.

    Science.gov (United States)

    Miller, Kristen P; Gowtham, Yogender Kumar; Henson, J Michael; Harcum, Sarah W

    2012-01-01

    The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  5. Phenotypic and genetic diversity of Saccharomyces contaminants isolated from lager breweries and their phylogenetic relationship with brewing yeasts

    DEFF Research Database (Denmark)

    Jespersen, Lene; Kühle, Alis Van der Aa; Petersen, Kamilla M.

    2000-01-01

    -amplified intergenic transcribed spacer (ITS) regions. Chromosome length polymorphism (CLP) was evident among the Saccharomyces brewing contaminants with chromosome profiles typical of Saccharomyces sensu stricto. Based upon cluster analysis of their chromosome profiles the majority of the brewing contaminants could...... be grouped as either S. cerevisiae or S. pastorianus/S. bayanus. Further, the technique was able to differentiate between almost all brewing contaminants and to separate them from any specific lager brewing yeast. The diversity of the Saccharomyces brewing contaminants clearly demonstrated by their CLP...... in the SaccharomYces brewing contaminants indicate their adaptation to a maltose-enriched environment....

  6. Comportamento celular e resposta antioxidante diferenciados de Saccharomyces cerevisiae e de Saccharomyces chevalieri ao metavanadato de amónio Different cellular behaviour and antioxidant response of Saccharomyces cerevisiae and Saccharomyces chevalieri growing in presence of ammonium metavanadate

    Directory of Open Access Journals (Sweden)

    R. Ferreira

    2007-01-01

    Full Text Available A fermentação do vinho é um processo microbiológico complexo que requere a presença de leveduras adaptadas a condições de stresse. No ambiente celular de organismos aeróbios ocorrem naturalmente espécies reactivas de oxigénio (ROS como subprodutos da respiração mitocondrial. A elevada reactividade destas espécies químicas pode gerar danos moleculares que, em alguns casos, levam à morte celular. Em condições fisiológicas normais ou como resposta ao stresse oxidativo, a célula pode desencadear respostas adaptativas que envolvem mecanismos antioxidantes como os enzimas glutationo redutase (GR; EC 1.6.4.2 e catalases T (CAT T; EC 1.11.1.6 e A (CAT A; EC 1.11.1.6. O vanádio, um metal pesado presente em alguns fitofármacos, pode também com portar-se como um gerador de ROS, alterando o estado redox intracelular e exercendo efeitos nocivos em leveduras expostas a quantidade excessiva deste elemento. O principal objectivo deste trabalho foi comparar o efeito do metavanadato de amónio (NH4VO3, um sal pentavalente de vanádio, na viabilidade celular e nas actividades enzimáticas GR, CAT T e CAT A das leveduras vínicas Saccharomyces cerevisiae UE-ME3 e Saccharomyces chevalieri UE-ME1. Os resultados obtidos mostram que S. chevalieri UE-ME1 revelou menor tolerância ao NH4VO3 do que S. cerevisiae UE-ME3, uma vez que culturas de S. chevalieri não sobreviveram para valores de concentração do sal de vanádio superiores a 7,5 mM enquanto que células de S. cerevisiae mantiveram-se viáveis em presença de metavanadato de amónio 75 mM. As actividades enzimáticas estudadas apresentaram em S. chevalieri valores muito inferiores aos que foram determinados em S. cerevisiae embora em ambas as espécies de levedura o NH4VO3 pareça comportarse como um indutor de stresse oxidativo ao provocar um decréscimo significativo da actividade GR (PThe fermentation of wine is a complex microbiological process which requires yeast adaptation to stress

  7. Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

    Directory of Open Access Journals (Sweden)

    Ancuta Mihaela Rotar

    2013-11-01

    Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.

  8. Quality control of inclusion bodies in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Schweder Thomas

    2010-05-01

    Full Text Available Abstract Background Bacterial inclusion bodies (IBs are key intermediates for protein production. Their quality affects the refolding yield and further purification. Recent functional and structural studies have revealed that IBs are not dead-end aggregates but undergo dynamic changes, including aggregation, refunctionalization of the protein and proteolysis. Both, aggregation of the folding intermediates and turnover of IBs are influenced by the cellular situation and a number of well-studied chaperones and proteases are included. IBs mostly contain only minor impurities and are relatively homogenous. Results IBs of α-glucosidase of Saccharomyces cerevisiae after overproduction in Escherichia coli contain a large amount of (at least 12 different major product fragments, as revealed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE. Matrix-Assisted-Laser-Desorption/Ionization-Time-Of-Flight Mass-Spectrometry (MALDI-ToF MS identification showed that these fragments contain either the N- or the C-terminus of the protein, therefore indicate that these IBs are at least partially created by proteolytic action. Expression of α-glucosidase in single knockout mutants for the major proteases ClpP, Lon, OmpT and FtsH which are known to be involved in the heat shock like response to production of recombinant proteins or to the degradation of IB proteins, clpP, lon, ompT, and ftsH did not influence the fragment pattern or the composition of the IBs. The quality of the IBs was also not influenced by the sampling time, cultivation medium (complex and mineral salt medium, production strategy (shake flask, fed-batch fermentation process, production strength (T5-lac or T7 promoter, strain background (K-12 or BL21, or addition of different protease inhibitors during IB preparation. Conclusions α-glucosidase is fragmented before aggregation, but neither by proteolytic action on the IBs by the common major proteases, nor during downstream IB

  9. Non-Saccharomyces in Wine: Effect Upon Oenococcus oeni and Malolactic Fermentation.

    Science.gov (United States)

    Balmaseda, Aitor; Bordons, Albert; Reguant, Cristina; Bautista-Gallego, Joaquín

    2018-01-01

    This work is a short review of the interactions between oenological yeasts and lactic acid bacteria (LAB), especially Oenococcus oeni , the main species carrying out the malolactic fermentation (MLF). The emphasis has been placed on non- Saccharomyces effects due to their recent increased interest in winemaking. Those interactions are variable, ranging from inhibitory, to neutral and stimulatory and are mediated by some known compounds, which will be discussed. One phenomena responsible of inhibitory interactions is the media exhaustion by yeasts, and particularly a decrease in L-malic acid by some non- Saccharomyces . Clearly ethanol is the main inhibitory compound of LAB produced by S. cerevisiae , but non- Saccharomyces can be used to decrease it. Sulfur dioxide and medium chain fatty acids (MCFAs) produced by yeasts can exhibit inhibitory effect upon LAB or even result lethal. Interestingly mixed fermentations with non- Saccharomyces present less MCFA concentration. Among organic acids derived as result of yeast metabolism, succinic acid seems to be the most related with MLF inhibition. Several protein factors produced by S. cerevisiae inhibiting O. oeni have been described, but they have not been studied in non- Saccharomyces . According to the stimulatory effects, the use of non- Saccharomyces can increase the concentration of favorable mediators such as citric acid, pyruvic acid, or other compounds derived of yeast autolysis such as peptides, glucans, or mannoproteins. The emergence of non- Saccharomyces in winemaking present a new scenario in which MLF has to take place. For this reason, new tools and approaches should be explored to better understand this new winemaking context.

  10. Non-Saccharomyces in Wine: Effect Upon Oenococcus oeni and Malolactic Fermentation

    Directory of Open Access Journals (Sweden)

    Aitor Balmaseda

    2018-03-01

    Full Text Available This work is a short review of the interactions between oenological yeasts and lactic acid bacteria (LAB, especially Oenococcus oeni, the main species carrying out the malolactic fermentation (MLF. The emphasis has been placed on non-Saccharomyces effects due to their recent increased interest in winemaking. Those interactions are variable, ranging from inhibitory, to neutral and stimulatory and are mediated by some known compounds, which will be discussed. One phenomena responsible of inhibitory interactions is the media exhaustion by yeasts, and particularly a decrease in L-malic acid by some non-Saccharomyces. Clearly ethanol is the main inhibitory compound of LAB produced by S. cerevisiae, but non-Saccharomyces can be used to decrease it. Sulfur dioxide and medium chain fatty acids (MCFAs produced by yeasts can exhibit inhibitory effect upon LAB or even result lethal. Interestingly mixed fermentations with non-Saccharomyces present less MCFA concentration. Among organic acids derived as result of yeast metabolism, succinic acid seems to be the most related with MLF inhibition. Several protein factors produced by S. cerevisiae inhibiting O. oeni have been described, but they have not been studied in non-Saccharomyces. According to the stimulatory effects, the use of non-Saccharomyces can increase the concentration of favorable mediators such as citric acid, pyruvic acid, or other compounds derived of yeast autolysis such as peptides, glucans, or mannoproteins. The emergence of non-Saccharomyces in winemaking present a new scenario in which MLF has to take place. For this reason, new tools and approaches should be explored to better understand this new winemaking context.

  11. Hybridization and adaptive evolution of diverse Saccharomyces species for cellulosic biofuel production.

    Science.gov (United States)

    Peris, David; Moriarty, Ryan V; Alexander, William G; Baker, EmilyClare; Sylvester, Kayla; Sardi, Maria; Langdon, Quinn K; Libkind, Diego; Wang, Qi-Ming; Bai, Feng-Yan; Leducq, Jean-Baptiste; Charron, Guillaume; Landry, Christian R; Sampaio, José Paulo; Gonçalves, Paula; Hyma, Katie E; Fay, Justin C; Sato, Trey K; Hittinger, Chris Todd

    2017-01-01

    Lignocellulosic biomass is a common resource across the globe, and its fermentation offers a promising option for generating renewable liquid transportation fuels. The deconstruction of lignocellulosic biomass releases sugars that can be fermented by microbes, but these processes also produce fermentation inhibitors, such as aromatic acids and aldehydes. Several research projects have investigated lignocellulosic biomass fermentation by the baker's yeast Saccharomyces cerevisiae . Most projects have taken synthetic biological approaches or have explored naturally occurring diversity in S. cerevisiae to enhance stress tolerance, xylose consumption, or ethanol production. Despite these efforts, improved strains with new properties are needed. In other industrial processes, such as wine and beer fermentation, interspecies hybrids have combined important traits from multiple species, suggesting that interspecies hybridization may also offer potential for biofuel research. To investigate the efficacy of this approach for traits relevant to lignocellulosic biofuel production, we generated synthetic hybrids by crossing engineered xylose-fermenting strains of S. cerevisiae with wild strains from various Saccharomyces species. These interspecies hybrids retained important parental traits, such as xylose consumption and stress tolerance, while displaying intermediate kinetic parameters and, in some cases, heterosis (hybrid vigor). Next, we exposed them to adaptive evolution in ammonia fiber expansion-pretreated corn stover hydrolysate and recovered strains with improved fermentative traits. Genome sequencing showed that the genomes of these evolved synthetic hybrids underwent rearrangements, duplications, and deletions. To determine whether the genus Saccharomyces contains additional untapped potential, we screened a genetically diverse collection of more than 500 wild, non-engineered Saccharomyces isolates and uncovered a wide range of capabilities for traits relevant to

  12. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract....... The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory...... to conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...

  13. Zymogram profiling of superoxide dismutase and catalase activities allows Saccharomyces and non-Saccharomyces species differentiation and correlates to their fermentation performance.

    Science.gov (United States)

    Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

    2013-05-01

    Aerobic organisms have devised several enzymatic and non-enzymatic antioxidant defenses to deal with reactive oxygen species (ROS) produced by cellular metabolism. To combat such stress, cells induce ROS scavenging enzymes such as catalase, peroxidase, superoxide dismutase (SOD) and glutathione reductase. In the present research, we have used a double staining technique of SOD and catalase enzymes in the same polyacrylamide gel to analyze the different antioxidant enzymatic activities and protein isoforms present in Saccharomyces and non-Saccharomyces yeast species. Moreover, we used a technique to differentially detect Sod1p and Sod2p on gel by immersion in NaCN, which specifically inhibits the Sod1p isoform. We observed unique SOD and catalase zymogram profiles for all the analyzed yeasts and we propose this technique as a new approach for Saccharomyces and non-Saccharomyces yeast strains differentiation. In addition, we observed functional correlations between SOD and catalase enzyme activities, accumulation of essential metabolites, such as glutathione and trehalose, and the fermentative performance of different yeasts strains with industrial relevance.

  14. Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae.

    Science.gov (United States)

    Qiu, Yixuan; Hassaninasab, Azam; Han, Gil-Soo; Carman, George M

    2016-12-16

    In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1-77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1-77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae*

    Science.gov (United States)

    Qiu, Yixuan; Hassaninasab, Azam; Han, Gil-Soo; Carman, George M.

    2016-01-01

    In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1–77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1–77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA. PMID:27834677

  16. The effect of medium structure complexity on the growth of Saccharomyces cerevisiae in gelatin-dextran systems.

    Science.gov (United States)

    Boons, Kathleen; Noriega, Estefanía; Verherstraeten, Niels; David, Charlotte C; Hofkens, Johan; Van Impe, Jan F

    2015-04-16

    As most food systems are (semi-)solid, the effect of food structure on bacterial growth has been widely acknowledged. However, studies on the growth dynamics of yeasts have neglected the effect of food structure. In this paper, the growth dynamics of the spoilage yeast Saccharomyces cerevisiae was investigated at 23.5 °C in broth, singular, homogeneous biopolymer systems and binary biopolymer systems with a heterogeneous microstructure. The biopolymers gelatin and dextran were used to introduce the different levels of structure. The metabolizing ability of gelatin and dextran by S. cerevisiae was examined. To study microbial behavior in the binary systems at the micro level, mixtures were imaged with confocal laser scanning microscopy (CLSM). Growth dynamics and microscopic images of S. cerevisiae were compared with those obtained for Escherichia coli in the same model system (Boons et al., 2014). Different phase-separated, heterogeneous microstructures were obtained by changing the amount of added gelatin and dextran. Regardless of the microstructure, S. cerevisiae was preferentially located in the dextran phase. Metabolizing ability-tests indicated that gelatin could be consumed by S. cerevisiae but in the presence of glucose, no change in gelatin concentration was observed. No indication of dextran metabolizing ability was observed. When supplementing broth with gelatin or dextran alone, an enhanced growth rate and maximum cell density were observed. This enhancement was further increased by adding a second biopolymer, introducing a heterogeneous microstructure and hence increasing the medium structure complexity. The results obtained indicate that food structure complexity plays a significant role in the growth dynamics of S. cerevisiae, an important food spoiler. Copyright © 2014. Published by Elsevier B.V.

  17. Evaluation of cytochrome P-450 concentration in Saccharomyces cerevisiae strains

    Directory of Open Access Journals (Sweden)

    Míriam Cristina Sakuragui Matuo

    2010-09-01

    Full Text Available Saccharomyces cerevisiae has been widely used in mutagenicity tests due to the presence of a cytochrome P-450 system, capable of metabolizing promutagens to active mutagens. There are a large number of S. cerevisiae strains with varying abilities to produce cytochrome P-450. However, strain selection and ideal cultivation conditions are not well defined. We compared cytochrome P-450 levels in four different S. cerevisiae strains and evaluated the cultivation conditions necessary to obtain the highest levels. The amount of cytochrome P-450 produced by each strain varied, as did the incubation time needed to reach the maximum level. The highest cytochrome P-450 concentrations were found in media containing fermentable sugars. The NCYC 240 strain produced the highest level of cytochrome P-450 when grown in the presence of 20 % (w/v glucose. The addition of ethanol to the media also increased cytochrome P-450 synthesis in this strain. These results indicate cultivation conditions must be specific and well-established for the strain selected in order to assure high cytochrome P-450 levels and reliable mutagenicity results.Linhagens de Saccharomyces cerevisiae tem sido amplamente empregadas em testes de mutagenicidade devido à presença de um sistema citocromo P-450 capaz de metabolizar substâncias pró-mutagênicas à sua forma ativa. Devido à grande variedade de linhagens de S. cerevisiae com diferentes capacidades de produção de citocromo P-450, torna-se necessária a seleção de cepas, bem como a definição das condições ideais de cultivo. Neste trabalho, foram comparados os níveis de citocromo P-450 em quatro diferentes linhagens de S. cerevisiae e avaliadas as condições de cultivo necessárias para obtenção de altas concentrações deste sistema enzimático. O maior nível enzimático foi encontrado na linhagem NCYC 240 em presença de 20 % de glicose (p/v. A adição de etanol ao meio de cultura também produziu um aumento na s

  18. Photoinactivation of mcr-1 positive Escherichia coli

    Science.gov (United States)

    Caires, C. S. A.; Leal, C. R. B.; Rodrigues, A. C. S.; Lima, A. R.; Silva, C. M.; Ramos, C. A. N.; Chang, M. R.; Arruda, E. J.; Oliveira, S. L.; Nascimento, V. A.; Caires, A. R. L.

    2018-01-01

    The emergence of plasmid-mediated colistin resistance in Enterobacteriaceae, mostly in Escherichia coli due to the mcr-1 gene, has revealed the need to develop alternative approaches in treating mcr-1 positive bacterial infections. This is because colistin is a broad-spectrum antibiotic and one of the ‘last-resort’ antibiotics for multidrug resistant bacteria. The present study evaluated for the first time, to the best of our knowledge, the efficacy of photoinactivation processes to kill a known mcr-1 positive E. coli strain. Eosin methylene-blue (EMB) was investigated as a photoantimicrobial agent for inhibiting the growth of a mcr-1 positive E. coli strain obtained from a patient with a diabetic foot infection. The photoantimicrobial activity of EMB was also tested in a non-multidrug resistant E. coli strain. The photoinactivation process was tested using light doses in the 30-45 J cm-2 range provided by a LED device emitting at 625 nm. Our findings demonstrate that a mcr-1 positive E. coli strain is susceptible to photoinactivation. The results show that the EMB was successfully photoactivated, regardless of the bacterial multidrug resistance; inactivating the bacterial growth by oxidizing the cells in accordance with the generation of the oxygen reactive species. Our results suggest that bacterial photoinactivation is an alternative and effective approach to kill mcr-1 positive bacteria.

  19. Profiling of Escherichia coli Chromosome database.

    Science.gov (United States)

    Yamazaki, Yukiko; Niki, Hironori; Kato, Jun-ichi

    2008-01-01

    The Profiling of Escherichia coli Chromosome (PEC) database (http://www.shigen.nig.ac.jp/ecoli/pec/) is designed to allow E. coli researchers to efficiently access information from functional genomics studies. The database contains two principal types of data: gene essentiality and a large collection of E. coli genetic research resources. The essentiality data are based on data compilation from published single-gene essentiality studies and on cell growth studies of large-deletion mutants. Using the circular and linear viewers for both whole genomes and the minimal genome, users can not only gain an overview of the genome structure but also retrieve information on contigs, gene products, mutants, deletions, and so forth. In particular, genome-wide exhaustive mutants are an essential resource for studying E. coli gene functions. Although the genomic database was constructed independently from the genetic resources database, users may seamlessly access both types of data. In addition to these data, the PEC database also provides a summary of homologous genes of other bacterial genomes and of protein structure information, with a comprehensive interface. The PEC is thus a convenient and useful platform for contemporary E. coli researchers.

  20. Functional characterization of a rice de novo DNA methyltransferase, OsDRM2, expressed in Escherichia coli and yeast

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Jinsong, E-mail: pangjs542@nenu.edu.cn [Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun, Jilin 130024 (China); Dong, Mingyue; Li, Ning; Zhao, Yanli [Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun, Jilin 130024 (China); Liu, Bao, E-mail: baoliu@nenu.edu.cn [Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun, Jilin 130024 (China)

    2013-03-01

    Highlights: ► A rice de novo DNA methyltransferase OsDRM2 was cloned. ► In vitro methylation activity of OsDRM2 was characterized with Escherichia coli. ► Assays of OsDRM2 in vivo methylation were done with Saccharomyces cerevisiae. ► OsDRM2 methylation activity is not preferential to any type of cytosine context. ► The activity of OsDRM2 is independent of RdDM pathway. - Abstract: DNA methylation of cytosine nucleotides is an important epigenetic modification that occurs in most eukaryotic organisms and is established and maintained by various DNA methyltransferases together with their co-factors. There are two major categories of DNA methyltransferases: de novo and maintenance. Here, we report the isolation and functional characterization of a de novo methyltransferase, named OsDRM2, from rice (Oryza sativa L.). The full-length coding region of OsDRM2 was cloned and transformed into Escherichia coli and Saccharomyces cerevisiae. Both of these organisms expressed the OsDRM2 protein, which exhibited stochastic de novo methylation activity in vitro at CG, CHG, and CHH di- and tri-nucleotide patterns. Two lines of evidence demonstrated the de novo activity of OsDRM2: (1) a 5′-CCGG-3′ containing DNA fragment that had been pre-treated with OsDRM2 protein expressed in E. coli was protected from digestion by the CG-methylation-sensitive isoschizomer HpaII; (2) methylation-sensitive amplified polymorphism (MSAP) analysis of S. cerevisiae genomic DNA from transformants that had been introduced with OsDRM2 revealed CG and CHG methylation levels of 3.92–9.12%, and 2.88–6.93%, respectively, whereas the mock control S. cerevisiae DNA did not exhibit cytosine methylation. These results were further supported by bisulfite sequencing of the 18S rRNA and EAF5 genes of the transformed S. cerevisiae, which exhibited different DNA methylation patterns, which were observed in the genomic DNA. Our findings establish that OsDRM2 is an active de novo DNA

  1. Functional characterization of a rice de novo DNA methyltransferase, OsDRM2, expressed in Escherichia coli and yeast

    International Nuclear Information System (INIS)

    Pang, Jinsong; Dong, Mingyue; Li, Ning; Zhao, Yanli; Liu, Bao

    2013-01-01

    Highlights: ► A rice de novo DNA methyltransferase OsDRM2 was cloned. ► In vitro methylation activity of OsDRM2 was characterized with Escherichia coli. ► Assays of OsDRM2 in vivo methylation were done with Saccharomyces cerevisiae. ► OsDRM2 methylation activity is not preferential to any type of cytosine context. ► The activity of OsDRM2 is independent of RdDM pathway. - Abstract: DNA methylation of cytosine nucleotides is an important epigenetic modification that occurs in most eukaryotic organisms and is established and maintained by various DNA methyltransferases together with their co-factors. There are two major categories of DNA methyltransferases: de novo and maintenance. Here, we report the isolation and functional characterization of a de novo methyltransferase, named OsDRM2, from rice (Oryza sativa L.). The full-length coding region of OsDRM2 was cloned and transformed into Escherichia coli and Saccharomyces cerevisiae. Both of these organisms expressed the OsDRM2 protein, which exhibited stochastic de novo methylation activity in vitro at CG, CHG, and CHH di- and tri-nucleotide patterns. Two lines of evidence demonstrated the de novo activity of OsDRM2: (1) a 5′-CCGG-3′ containing DNA fragment that had been pre-treated with OsDRM2 protein expressed in E. coli was protected from digestion by the CG-methylation-sensitive isoschizomer HpaII; (2) methylation-sensitive amplified polymorphism (MSAP) analysis of S. cerevisiae genomic DNA from transformants that had been introduced with OsDRM2 revealed CG and CHG methylation levels of 3.92–9.12%, and 2.88–6.93%, respectively, whereas the mock control S. cerevisiae DNA did not exhibit cytosine methylation. These results were further supported by bisulfite sequencing of the 18S rRNA and EAF5 genes of the transformed S. cerevisiae, which exhibited different DNA methylation patterns, which were observed in the genomic DNA. Our findings establish that OsDRM2 is an active de novo DNA

  2. Genetic and phenotypic characterization of Saccharomyces spp. strains isolated in distillery plants.

    Science.gov (United States)

    Úbeda, Juan F; Chacón-Ocaña, Maria; Díaz-Hellín, Patricia; Ramírez-Pérez, Hector; Briones, Ana

    2016-06-01

    In this study, the biodiversity and some interesting phenotypic properties of Saccharomyces wild yeasts isolated in distilleries, at least 100 years old, located in La Mancha (Spain), were determined. Strains were genetically characterized by RFLP-mtDNA, which confirmed a great genetic biodiversity with 73% of strains with different mtDNA profiles, highlighting the large variability found in sweet and fermented piquette substrata. The predominant species identified was S. cerevisiae, followed by S. paradoxus and S. bayanus Due to the residual sugar-alcohol extraction process using warm water, a great number of thermophilic Saccharomyces strains with a great cell vitality were found to have potential use as starters in distillery plants. Interesting technological properties such as cell vitality and growth rate at different temperatures were studied. The thermal washing process for the extraction of alcohol and reducing sugars of some raw materials contributes to the presence of Saccharomyces strains with technologically interesting properties, especially in terms of vitality and resistance to high temperatures. Due to the fact that fermentation is spontaneous, the yeast biota of these environments, Saccharomyces and non-Saccharomyces, is very varied so these ecological niches are microbial reserves of undoubted biotechnological interest. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Therapeutic activity of a Saccharomyces cerevisiae-based probiotic and inactivated whole yeast on vaginal candidiasis.

    Science.gov (United States)

    Pericolini, Eva; Gabrielli, Elena; Ballet, Nathalie; Sabbatini, Samuele; Roselletti, Elena; Cayzeele Decherf, Amélie; Pélerin, Fanny; Luciano, Eugenio; Perito, Stefano; Jüsten, Peter; Vecchiarelli, Anna

    2017-01-02

    Vulvovaginal candidiasis is the most prevalent vaginal infection worldwide and Candida albicans is its major agent. Vulvovaginal candidiasis is characterized by disruption of the vaginal microbiota composition, as happens following large spectrum antibiotic usage. Recent studies support the effectiveness of oral and local probiotic treatment for prevention of recurrent vulvovaginal candidiasis. Saccharomyces cerevisiae is a safe yeast used as, or for, the production of ingredients for human nutrition and health. Here, we demonstrate that vaginal administration of probiotic Saccharomyces cerevisiae live yeast (GI) and, in part, inactivated whole yeast Saccharomyces cerevisiae (IY), used as post-challenge therapeutics, was able to positively influence the course of vaginal candidiasis by accelerating the clearance of the fungus. This effect was likely due to multiple interactions of Saccharomyces cerevisiae with Candida albicans. Both live and inactivated yeasts induced coaggregation of Candida and consequently inhibited its adherence to epithelial cells. However, only the probiotic yeast was able to suppress some major virulence factors of Candida albicans such as the ability to switch from yeast to mycelial form and the capacity to express several aspartyl proteases. The effectiveness of live yeast was higher than that of inactivated whole yeast suggesting that the synergy between mechanical effects and biological effects were dominant over purely mechanical effects. The protection of epithelial cells to Candida-induced damage was also observed. Overall, our data show for the first time that Saccharomyces cerevisiae-based ingredients, particularly the living cells, can exert beneficial therapeutic effects on a widespread vaginal mucosal infection.

  4. Screening and evaluation of the glucoside hydrolase activity in Saccharomyces and Brettanomyces brewing yeasts.

    Science.gov (United States)

    Daenen, L; Saison, D; Sterckx, F; Delvaux, F R; Verachtert, H; Derdelinckx, G

    2008-02-01

    The aim of this study was to select and examine Saccharomyces and Brettanomyces brewing yeasts for hydrolase activity towards glycosidically bound volatile compounds. A screening for glucoside hydrolase activity of 58 brewing yeasts belonging to the genera Saccharomyces and Brettanomyces was performed. The studied Saccharomyces brewing yeasts did not show 1,4-beta-glucosidase activity, but a strain dependent beta-glucanase activity was observed. Some Brettanomyces species did show 1,4-beta-glucosidase activity. The highest constitutive activity was found in Brettanomyces custersii. For the most interesting strains the substrate specificity was studied and their activity was evaluated in fermentation experiments with added hop glycosides. Fermentations with Br. custersii led to the highest release of aglycones. Pronounced exo-beta-glucanase activity in Saccharomyces brewing yeasts leads to a higher release of certain aglycones. Certain Brettanomyces brewing yeasts, however, are more interesting for hydrolysis of glycosidically bound volatiles of hops. The release of flavour active compounds from hop glycosides opens perspectives for the bioflavouring and product diversification of beverages like beer. The release can be enhanced by using Saccharomyces strains with high exo-beta-glucanase activity. Higher activities can be found in Brettanomyces species with beta-glucosidase activity.

  5. Role of Saccharomyces boulardii in Reduction of Neonatal Hyperbilirubinemia.

    Science.gov (United States)

    Suganthi, V; Das, A Gokul

    2016-11-01

    Probiotics are known to reduce the severity of hyperbilirubinemia. This study was done to evaluate the effect of probiotic on neonatal hyperbilirubinemia in term neonates. A total of 181 healthy term neonates after birth were divided into a control group (n=95) and a treatment group (n=86) randomly and treated with placebo and probiotic ( Saccharomyces boulardii ) respectively. A total of two doses were given orally in the first two consecutive days. The serum bilirubin levels were detected on day three of life. Babies were exclusively breastfed, clinical outcome was recorded. Comparison between groups was made by the non-parametric Mann-Whitney test. Analysis of Variance (ANOVA) was used to assess the quantitative variables. A p-value of jaundice is 6.5mg% and in the treatment group is 5mg%. In patient with clinical jaundice, it is 13.6mg% in control group and 10.7mg% in the treatment group. The p-value was found to be Probiotics lowered the serum bilirubin level of healthy neonate with jaundice safely and significantly without any adverse reaction.

  6. Efficient Sporulation of Saccharomyces cerevisiae in a 96 Multiwell Format.

    Science.gov (United States)

    Paulissen, Scott M; Huang, Linda S

    2016-09-17

    During times of nutritional stress, Saccharomyces cerevisiae undergoes gametogenesis, known as sporulation. Diploid yeast cells that are starved for nitrogen and carbon will initiate the sporulation process. The process of sporulation includes meiosis followed by spore formation, where the haploid nuclei are packaged into environmentally resistant spores. We have developed methods for the efficient sporulation of budding yeast in 96 multiwell plates, to increase the throughput of screening yeast cells for sporulation phenotypes. These methods are compatible with screening with yeast containing plasmids requiring nutritional selection, when appropriate minimal media is used, or with screening yeast with genomic alterations, when a rich presporulation regimen is used. We find that for this method, aeration during sporulation is critical for spore formation, and have devised techniques to ensure sufficient aeration that are compatible with the 96 multiwell plate format. Although these methods do not achieve the typical ~80% level of sporulation that can be achieved in large-volume flask based experiments, these methods will reliably achieve about 50-60% level of sporulation in small-volume multiwell plates.

  7. Sucrose fermentation by Saccharomyces cerevisiae lacking hexose transport.

    Science.gov (United States)

    Batista, Anderson S; Miletti, Luiz C; Stambuk, Boris U

    2004-01-01

    Sucrose is the major carbon source used by Saccharomyces cerevisiae during production of baker's yeast, fuel ethanol and several distilled beverages. It is generally accepted that sucrose fermentation proceeds through extracellular hydrolysis of the sugar, mediated by the periplasmic invertase, producing glucose and fructose that are transported into the cells and metabolized. In the present work we analyzed the contribution to sucrose fermentation of a poorly characterized pathway of sucrose utilization by S. cerevisiae cells, the active transport of the sugar through the plasma membrane and its intracellular hydrolysis. A yeast strain that lacks the major hexose transporters (hxt1-hxt7 and gal2) is incapable of growing on or fermenting glucose or fructose. Our results show that this hxt-null strain is still able to ferment sucrose due to direct uptake of the sugar into the cells. Deletion of the AGT1 gene, which encodes a high-affinity sucrose-H(+) symporter, rendered cells incapable of sucrose fermentation. Since sucrose is not an inducer of the permease, expression of the AGT1 must be constitutive in order to allow growth of the hxt-null strain on sucrose. The molecular characterization of active sucrose transport and fermentation by S. cerevisiae cells opens new opportunities to optimize yeasts for sugarcane-based industrial processes.

  8. Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation

    Science.gov (United States)

    Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie

    2013-01-01

    The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation. PMID:24056467

  9. Saccharomyces cerevisiae Fermentation Effects on Pollen: Archaeological Implications

    Directory of Open Access Journals (Sweden)

    Crystal A. Dozier

    2016-03-01

    Full Text Available Pollen is the reproductive agent of flowering plants; palynology is utilized by archaeologists because sporopollenin, a major component in the exine of pollen grains, is resistant to decay and morphologically distinctive. Wine, beer, and mead have been identified in the archaeological record by palynological assessment due to indicator species or due to a pollen profile similar to that recovered from honey, a common source of sugar in a variety of fermented beverages. While most palynologists have assumed that pollen grains are resistant to alcoholic fermentation, a recent study in food science implies that pollen is a yeast nutrient because pollen-enriched meads produce more alcohol. The experiment presented here explores the potential distortion of the pollen record through fermentation by brewing a traditional, pollen-rich mead with Saccharomyces cerevisiae. In this experiment, the pollen grains did not undergo any discernible morphological changes nor were distorted in the pollen profile. Any nutrition that the yeast garners from the pollen therefore leaves sporopollenin intact. These results support palynological research on residues of alcoholic beverages and confirms that the fermentation process does not distort the pollen profile of the original substance. The paper concludes with the potential and limits of palynological study to assess fermentation within the archaeological record.

  10. Saccharomyces cerevisiae in the Production of Fermented Beverages

    Directory of Open Access Journals (Sweden)

    Graeme M Walker

    2016-11-01

    Full Text Available Alcoholic beverages are produced following the fermentation of sugars by yeasts, mainly (but not exclusively strains of the species, Saccharomyces cerevisiae. The sugary starting materials may emanate from cereal starches (which require enzymatic pre-hydrolysis in the case of beers and whiskies, sucrose-rich plants (molasses or sugar juice from sugarcane in the case of rums, or from fruits (which do not require pre-hydrolysis in the case of wines and brandies. In the presence of sugars, together with other essential nutrients such as amino acids, minerals and vitamins, S. cerevisiae will conduct fermentative metabolism to ethanol and carbon dioxide (as the primary fermentation metabolites as the cells strive to make energy and regenerate the coenzyme NAD+ under anaerobic conditions. Yeasts will also produce numerous secondary metabolites which act as important beverage flavour congeners, including higher alcohols, esters, carbonyls and sulphur compounds. These are very important in dictating the final flavour and aroma characteristics of beverages such as beer and wine, but also in distilled beverages such as whisky, rum and brandy. Therefore, yeasts are of vital importance in providing the alcohol content and the sensory profiles of such beverages. This Introductory Chapter reviews, in general, the growth, physiology and metabolism of S. cerevisiae in alcoholic beverage fermentations.

  11. Functional relevance of water and glycerol channels in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sabir, Farzana; Loureiro-Dias, Maria C; Soveral, Graça; Prista, Catarina

    2017-05-01

    Our understanding of the functional relevance of orthodox aquaporins and aquaglyceroporins in Saccharomyces cerevisiae is essentially based on phenotypic variations obtained by expression/overexpression/deletion of these major intrinsic proteins in selected strains. These water/glycerol channels are considered crucial during various life-cycle phases, such as sporulation and mating and in some life processes such as rapid freeze-thaw tolerance, osmoregulation and phenomena associated with cell surface. Despite their putative functional roles not only as channels but also as sensors, their underlying mechanisms and their regulation are still poorly understood. In the present review, we summarize and discuss the physiological relevance of S. cerevisiae aquaporins (Aqy1 and Aqy2) and aquaglyceroporins (Fps1 and Yfl054c). In particular, the fact that most S. cerevisiae laboratory strains harbor genes coding for non-functional aquaporins, while wild and industrial strains possess at least one functional aquaporin, suggests that aquaporin activity is required for cell survival under more harsh conditions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Global gene response in Saccharomyces cerevisiae exposed to silver nanoparticles.

    Science.gov (United States)

    Niazi, Javed H; Sang, Byoung-In; Kim, Yeon Seok; Gu, Man Bock

    2011-08-01

    Silver nanoparticles (AgNPs), exhibiting a broad size range and morphologies with highly reactive facets, which are widely applicable in real-life but not fully verified for biosafety and ecotoxicity, were subjected to report transcriptome profile in yeast Saccharomyces cerevisiae. A large number of genes accounted for ∼3% and ∼5% of the genome affected by AgNPs and Ag-ions, respectively. Principal component and cluster analysis suggest that the different physical forms of Ag were the major cause in differential expression profile. Among 90 genes affected by both AgNPs and Ag-ions, metalloprotein mediating high resistance to copper (CUP1-1 and CUP1-2) were strongly induced by AgNPs (∼45-folds) and Ag-ions (∼22-folds), respectively. A total of 17 genes, responsive to chemical stimuli, stress, and transport processes, were differentially induced by AgNPs. The differential expression was also seen with Ag-ions that affected 73 up- and 161 down-regulating genes, and most of these were involved in ion transport and homeostasis. This study provides new information on the knowledge for impact of nanoparticles on living microorganisms that can be extended to other nanoparticles.

  13. Habitat Predicts Levels of Genetic Admixture in Saccharomyces cerevisiae

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    Viranga Tilakaratna

    2017-09-01

    Full Text Available Genetic admixture can provide material for populations to adapt to local environments, and this process has played a crucial role in the domestication of plants and animals. The model yeast, Saccharomyces cerevisiae, has been domesticated multiple times for the production of wine, sake, beer, and bread, but the high rate of admixture between yeast lineages has so far been treated as a complication for population genomic analysis. Here, we make use of the low recombination rate at centromeres to investigate admixture in yeast using a classic Bayesian approach and a locus-by-locus phylogenetic approach. Using both approaches, we find that S. cerevisiae from stable oak woodland habitats are less likely to show recent genetic admixture compared with those isolated from transient habitats such as fruits, wine, or human infections. When woodland yeast strains do show recent genetic admixture, the degree of admixture is lower than in strains from other habitats. Furthermore, S. cerevisiae populations from oak woodlands are genetically isolated from each other, with only occasional migration between woodlands and local fruit habitats. Application of the phylogenetic approach suggests that there is a previously undetected population in North Africa that is the closest outgroup to the European S. cerevisiae, including the domesticated Wine population. Careful testing for admixture in S. cerevisiae leads to a better understanding of the underlying population structure of the species and will be important for understanding the selective processes underlying domestication in this economically important species.

  14. Habitat Predicts Levels of Genetic Admixture in Saccharomyces cerevisiae.

    Science.gov (United States)

    Tilakaratna, Viranga; Bensasson, Douda

    2017-09-07

    Genetic admixture can provide material for populations to adapt to local environments, and this process has played a crucial role in the domestication of plants and animals. The model yeast, Saccharomyces cerevisiae , has been domesticated multiple times for the production of wine, sake, beer, and bread, but the high rate of admixture between yeast lineages has so far been treated as a complication for population genomic analysis. Here, we make use of the low recombination rate at centromeres to investigate admixture in yeast using a classic Bayesian approach and a locus-by-locus phylogenetic approach. Using both approaches, we find that S. cerevisiae from stable oak woodland habitats are less likely to show recent genetic admixture compared with those isolated from transient habitats such as fruits, wine, or human infections. When woodland yeast strains do show recent genetic admixture, the degree of admixture is lower than in strains from other habitats. Furthermore, S. cerevisiae populations from oak woodlands are genetically isolated from each other, with only occasional migration between woodlands and local fruit habitats. Application of the phylogenetic approach suggests that there is a previously undetected population in North Africa that is the closest outgroup to the European S. cerevisiae , including the domesticated Wine population. Careful testing for admixture in S. cerevisiae leads to a better understanding of the underlying population structure of the species and will be important for understanding the selective processes underlying domestication in this economically important species. Copyright © 2017 Tilakaratna and Bensasson.

  15. Bread, beer and wine: Saccharomyces cerevisiae diversity reflects human history.

    Science.gov (United States)

    Legras, Jean-Luc; Merdinoglu, Didier; Cornuet, Jean-Marie; Karst, Francis

    2007-05-01

    Fermented beverages and foods have played a significant role in most societies worldwide for millennia. To better understand how the yeast species Saccharomyces cerevisiae, the main fermenting agent, evolved along this historical and expansion process, we analysed the genetic diversity among 651 strains from 56 different geographical origins, worldwide. Their genotyping at 12 microsatellite loci revealed 575 distinct genotypes organized in subgroups of yeast types, i.e. bread, beer, wine, sake. Some of these groups presented unexpected relatedness: Bread strains displayed a combination of alleles intermediate between beer and wine strains, and strains used for rice wine and sake were most closely related to beer and bread strains. However, up to 28% of genetic diversity between these technological groups was associated with geographical differences which suggests local domestications. Focusing on wine yeasts, a group of Lebanese strains were basal in an F(ST) tree, suggesting a Mesopotamia-based origin of most wine strains. In Europe, migration of wine strains occurred through the Danube Valley, and around the Mediterranean Sea. An approximate Bayesian computation approach suggested a postglacial divergence (most probable period 10,000-12,000 bp). As our results suggest intimate association between man and wine yeast across centuries, we hypothesize that yeast followed man and vine migrations as a commensal member of grapevine flora.

  16. Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.

    Science.gov (United States)

    Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie; Courtin, Christophe M; Verstrepen, Kevin J

    2013-12-01

    The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation.

  17. Nuclear mitochondrial DNA activates replication in Saccharomyces cerevisiae.

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    Laurent Chatre

    Full Text Available The nuclear genome of eukaryotes is colonized by DNA fragments of mitochondrial origin, called NUMTs. These insertions have been associated with a variety of germ-line diseases in humans. The significance of this uptake of potentially dangerous sequences into the nuclear genome is unclear. Here we provide functional evidence that sequences of mitochondrial origin promote nuclear DNA replication in Saccharomyces cerevisiae. We show that NUMTs are rich in key autonomously replicating sequence (ARS consensus motifs, whose mutation results in the reduction or loss of DNA replication activity. Furthermore, 2D-gel analysis of the mrc1 mutant exposed to hydroxyurea shows that several NUMTs function as late chromosomal origins. We also show that NUMTs located close to or within ARS provide key sequence elements for replication. Thus NUMTs can act as independent origins, when inserted in an appropriate genomic context or affect the efficiency of pre-existing origins. These findings show that migratory mitochondrial DNAs can impact on the replication of the nuclear region they are inserted in.

  18. De novo biosynthesis of anthocyanins in Saccharomyces cerevisiae.

    Science.gov (United States)

    Eichenberger, Michael; Hansson, Anders; Fischer, David; Dürr, Lara; Naesby, Michael

    2018-06-01

    Anthocyanins (ACNs) are plant secondary metabolites responsible for most of the red, purple and blue colors of flowers, fruits and vegetables. They are increasingly used in the food and beverage industry as natural alternative to artificial colorants. Production of these compounds by fermentation of microorganisms would provide an attractive alternative. In this study, Saccharomyces cerevisiae was engineered for de novo production of the three basic anthocyanins, as well as the three main trans-flavan-3-ols. Enzymes from different plant sources were screened and efficient variants found for most steps of the biosynthetic pathway. However, the anthocyanidin synthase was identified as a major obstacle to efficient production. In yeast, this enzyme converts the majority of its natural substrates leucoanthocyanidins into the off-pathway flavonols. Nonetheless, de novo biosynthesis of ACNs was shown for the first time in yeast and for the first time in a single microorganism. It provides a framework for optimizing the activity of anthocyanidin synthase and represents an important step towards sustainable industrial production of these highly relevant molecules in yeast.

  19. Antimutators of mitochodrial and nuclear DNA in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Bianchi, L.; Foury, F.

    1982-01-01

    In Saccharomyces cerevisiae ten antimutator mutants have been isolated. The spontaneous occurrence of mitochondrial mutants resistant to erythromycin, oligomycin, and diuron is decreased 2-60-fold in these strains. The rate of forward and reverse spontaneous mutations of the nuclear genome is also reduced. The meiotic progenies arising from the crosses of seven mutants (LB 1 , LB 2 , LB 4 , LB 5 , LB 6 , LB 7 , LB 10 ) with an isogenic parental strain exhibit 2:2 segregations and therefore are the result of mutations in a single nuclear gene. The six mutants LB 1 , LB 2 , LB 4 , LB 6 , LB 7 , LB 10 are semidominant and determine six complementation groups. The mutant LB 5 is dominant and therefore cannot be assigned to any complementation group. The mutants. LB 1 , LB 4 and LB 1 0 are gamma-ray sensitive and, by tetrad analysis, it has been shown that gamma-ray sensitivity and spontaneous antimutability are the result of a single nuclear gene mutation. The other three mutants LB 3 , LB 8 and LB 9 exhibit complex tetrad segregations, typical of cytoplasmic inheritance and do not complement each other. However, although the mutations are semidominant, it has not been possible to detect any antimutator cytoductant among some 500 cytoductants carrying the karl 1-1 nucleus. (orig./AJ)

  20. Spontaneous and radiation induced gene conversion in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Rao, B.S.; Murthy, M.S.S.

    1977-01-01

    Spontaneous and radiation induced gene conversion to arginine independence was studied in a heteroallelic diploid strain of yeast Saccharomyces cerevisiae BZ 34. When stationary phase cells were incubated in phosphate buffer (pH 7 ) at 30 0 C under aerated condition for 48 hours, the conversion frequency increased by a factor of about 1000 times the background. This was found to be so even when the cells were incubated in saline (0.85%) or distilled water. Various conditions influencing this enhancement have been investigated. Conversion frequency enhancement was not significant under anoxic conditions and was absent at low temperatures and in log phase cells. Caffeine could inhibit this enhancement when present in the suspension medium. These results can be explained on the basis of the induction of meiosis in cells held in buffer. Microscopic examination confirmed this view. Under conditions not favourable for the onset of meiosis there is no significant enhancement in conversion frequency. In stationary phase cells exposed to series of gamma doses, the conversion frequency increases with dose. Post irradiation incubation in buffer further increases the conversion frequency. However, the increase expressed as the ratio of the conversion frequency on buffer holding to that on immediate plating decreased with increasing dose. This decrease in enhancement with increasing dose may be due to the dose dependent inhibition of meiosis. (author)

  1. Brazilian propolis protects Saccharomyces cerevisiae cells against oxidative stress

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    Rafael A. de Sá

    2013-09-01

    Full Text Available Propolis is a natural product widely used for humans. Due to its complex composition, a number of applications (antimicrobial, antiinflammatory, anesthetic, cytostatic and antioxidant have been attributed to this substance. Using Saccharomyces cerevisiae as a eukaryotic model we investigated the mechanisms underlying the antioxidant effect of propolis from Guarapari against oxidative stress. Submitting a wild type (BY4741 and antioxidant deficient strains (ctt1∆, sod1∆, gsh1∆, gtt1∆ and gtt2∆ either to 15 mM menadione or to 2 mM hydrogen peroxide during 60 min, we observed that all strains, except the mutant sod1∆, acquired tolerance when previously treated with 25 µg/mL of alcoholic propolis extract. Such a treatment reduced the levels of ROS generation and of lipid peroxidation, after oxidative stress. The increase in Cu/Zn-Sod activity by propolis suggests that the protection might be acting synergistically with Cu/Zn-Sod.

  2. The evolution of gene expression QTL in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    James Ronald

    2007-08-01

    Full Text Available Understanding the evolutionary forces that influence patterns of gene expression variation will provide insights into the mechanisms of evolutionary change and the molecular basis of phenotypic diversity. To date, studies of gene expression evolution have primarily been made by analyzing how gene expression levels vary within and between species. However, the fundamental unit of heritable variation in transcript abundance is the underlying regulatory allele, and as a result it is necessary to understand gene expression evolution at the level of DNA sequence variation. Here we describe the evolutionary forces shaping patterns of genetic variation for 1206 cis-regulatory QTL identified in a cross between two divergent strains of Saccharomyces cerevisiae. We demonstrate that purifying selection against mildly deleterious alleles is the dominant force governing cis-regulatory evolution in S. cerevisiae and estimate the strength of selection. We also find that essential genes and genes with larger codon bias are subject to slightly stronger cis-regulatory constraint and that positive selection has played a role in the evolution of major trans-acting QTL.

  3. Water-Transfer Slows Aging in Saccharomyces cerevisiae.

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    Aviv Cohen

    Full Text Available Transferring Saccharomyces cerevisiae cells to water is known to extend their lifespan. However, it is unclear whether this lifespan extension is due to slowing the aging process or merely keeping old yeast alive. Here we show that in water-transferred yeast, the toxicity of polyQ proteins is decreased and the aging biomarker 47Q aggregates at a reduced rate and to a lesser extent. These beneficial effects of water-transfer could not be reproduced by diluting the growth medium and depended on de novo protein synthesis and proteasomes levels. Interestingly, we found that upon water-transfer 27 proteins are downregulated, 4 proteins are upregulated and 81 proteins change their intracellular localization, hinting at an active genetic program enabling the lifespan extension. Furthermore, the aging-related deterioration of the heat shock response (HSR, the unfolded protein response (UPR and the endoplasmic reticulum-associated protein degradation (ERAD, was largely prevented in water-transferred yeast, as the activities of these proteostatic network pathways remained nearly as robust as in young yeast. The characteristics of young yeast that are actively maintained upon water-transfer indicate that the extended lifespan is the outcome of slowing the rate of the aging process.

  4. Water-Transfer Slows Aging in Saccharomyces cerevisiae.

    Science.gov (United States)

    Cohen, Aviv; Weindling, Esther; Rabinovich, Efrat; Nachman, Iftach; Fuchs, Shai; Chuartzman, Silvia; Gal, Lihi; Schuldiner, Maya; Bar-Nun, Shoshana

    2016-01-01

    Transferring Saccharomyces cerevisiae cells to water is known to extend their lifespan. However, it is unclear whether this lifespan extension is due to slowing the aging process or merely keeping old yeast alive. Here we show that in water-transferred yeast, the toxicity of polyQ proteins is decreased and the aging biomarker 47Q aggregates at a reduced rate and to a lesser extent. These beneficial effects of water-transfer could not be reproduced by diluting the growth medium and depended on de novo protein synthesis and proteasomes levels. Interestingly, we found that upon water-transfer 27 proteins are downregulated, 4 proteins are upregulated and 81 proteins change their intracellular localization, hinting at an active genetic program enabling the lifespan extension. Furthermore, the aging-related deterioration of the heat shock response (HSR), the unfolded protein response (UPR) and the endoplasmic reticulum-associated protein degradation (ERAD), was largely prevented in water-transferred yeast, as the activities of these proteostatic network pathways remained nearly as robust as in young yeast. The characteristics of young yeast that are actively maintained upon water-transfer indicate that the extended lifespan is the outcome of slowing the rate of the aging process.

  5. Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Sadi, Suharni

    1987-01-01

    Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae. S. cerevisiae suspensions of 1.5x10 8 clls/ml were exposed to single and fractionated doses of gamma irradiation, i.e. 0; 0.30; 0.60; 0.90; and 1.20 kGy in aerobic condition at dose rate of 1.63 kGy/hour. The fractionated doses were given with time interval of 15, 30 and 45 minutes. The fermentation was held at 30 0 C for 40 hours. It is seen that an increase of alcohol production was obtained when cells were irradiated at 0.60 kGy, although the result has no significant difference statistically with control. At the dose of 1.20 kGy the alcohol fermentation ability of S. cerevisiae decreased drastically as compared to control. Irradiation using single or fractionated doses with time interval of 15-45 minutes did not influence the alcohol production. Comparing the time interval of 45 minutes at 0.60 kGy and at 1.20 kGy, it appeared that the yield of alcohol was different. (author). 17 refs.; 4 figs

  6. Saccharomyces cerevisiae proteinase A excretion and wine making.

    Science.gov (United States)

    Song, Lulu; Chen, Yefu; Du, Yongjing; Wang, Xibin; Guo, Xuewu; Dong, Jian; Xiao, Dongguang

    2017-11-09

    Proteinase A (PrA), the major protease in Saccharomyces cerevisiae, plays an essential role in zymogen activation, sporulation, and other physiological processes in vivo. The extracellular secretion of PrA often occurs during alcoholic fermentation, especially in the later stages when the yeast cells are under stress conditions, and affects the quality and safety of fermented products. Thus, the mechanism underlying PrA excretion must be explored to improve the quality and safety of fermented products. This paper briefly introduces the structure and physiological function of PrA. Two transport routes of PrA, namely, the Golgi-to-vacuole pathway and the constitutive Golgi-to-plasma membrane pathway, are also discussed. Moreover, the research history and developments on the mechanism of extracellular PrA secretion are described. In addition, it is briefly discussed that calcium homeostasis plays an important role in the secretory pathway of proteins, implying that the regulation of PrA delivery to the plasma membrane requires the involvement of calcium ion. Finally, this review focuses on the effects of PrA excretion on wine making (including Chinese rice wine, grape wine, and beer brewage) and presents strategies to control PrA excretion.

  7. Asynchronous spore germination in isogenic natural isolates of Saccharomyces paradoxus.

    Science.gov (United States)

    Stelkens, Rike B; Miller, Eric L; Greig, Duncan

    2016-05-01

    Spores from wild yeast isolates often show great variation in the size of colonies they produce, for largely unknown reasons. Here we measure the colonies produced from single spores from six different wild Saccharomyces paradoxus strains. We found remarkable variation in spore colony sizes, even among spores that were genetically identical. Different strains had different amounts of variation in spore colony sizes, and variation was not affected by the number of preceding meioses, or by spore maturation time. We used time-lapse photography to show that wild strains also have high variation in spore germination timing, providing a likely mechanism for the variation in spore colony sizes. When some spores from a laboratory strain make small colonies, or no colonies, it usually indicates a genetic or meiotic fault. Here, we demonstrate that in wild strains spore colony size variation is normal. We discuss and assess potential adaptive and non-adaptive explanations for this variation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Nutrient sensing and signaling in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Conrad, Michaela; Schothorst, Joep; Kankipati, Harish Nag; Van Zeebroeck, Griet; Rubio-Texeira, Marta; Thevelein, Johan M

    2014-01-01

    The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth. PMID:24483210

  9. Mating-Type Genes and MAT Switching in Saccharomyces cerevisiae

    Science.gov (United States)

    Haber, James E.

    2012-01-01

    Mating type in Saccharomyces cerevisiae is determined by two nonhomologous alleles, MATa and MATα. These sequences encode regulators of the two different haploid mating types and of the diploids formed by their conjugation. Analysis of the MATa1, MATα1, and MATα2 alleles provided one of the earliest models of cell-type specification by transcriptional activators and repressors. Remarkably, homothallic yeast cells can switch their mating type as often as every generation by a highly choreographed, site-specific homologous recombination event that replaces one MAT allele with different DNA sequences encoding the opposite MAT allele. This replacement process involves the participation of two intact but unexpressed copies of mating-type information at the heterochromatic loci, HMLα and HMRa, which are located at opposite ends of the same chromosome-encoding MAT. The study of MAT switching has yielded important insights into the control of cell lineage, the silencing of gene expression, the formation of heterochromatin, and the regulation of accessibility of the donor sequences. Real-time analysis of MAT switching has provided the most detailed description of the molecular events that occur during the homologous recombinational repair of a programmed double-strand chromosome break. PMID:22555442

  10. Saccharomyces pastorianus: genomic insights inspiring innovation for industry.

    Science.gov (United States)

    Gibson, Brian; Liti, Gianni

    2015-01-01

    A combination of biological and non-biological factors has led to the interspecific hybrid yeast species Saccharomyces pastorianus becoming one of the world's most important industrial organisms. This yeast is used in the production of lager-style beers, the fermentation of which requires very low temperatures compared to other industrial fermentation processes. This group of organisms has benefited from both the whole-genome duplication in its ancestral lineage and the subsequent hybridization event between S. cerevisiae and S. eubayanus, resulting in strong fermentative ability. The hybrid has key traits, such as cold tolerance and good maltose- and maltotriose-utilizing ability, inherited either from the parental species or originating from genetic interactions between the parent genomes. Instability in the nascent allopolyploid hybrid genome may have contributed to rapid evolution of the yeast to tolerate conditions prevalent in the brewing environment. The recent discovery of S. eubayanus has provided new insights into the evolutionary history of S. pastorianus and may offer new opportunities for generating novel industrially-beneficial lager yeast strains. Copyright © 2014 John Wiley & Sons, Ltd.

  11. MAP kinase pathways in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Gustin, M. C.; Albertyn, J.; Alexander, M.; Davenport, K.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    A cascade of three protein kinases known as a mitogen-activated protein kinase (MAPK) cascade is commonly found as part of the signaling pathways in eukaryotic cells. Almost two decades of genetic and biochemical experimentation plus the recently completed DNA sequence of the Saccharomyces cerevisiae genome have revealed just five functionally distinct MAPK cascades in this yeast. Sexual conjugation, cell growth, and adaptation to stress, for example, all require MAPK-mediated cellular responses. A primary function of these cascades appears to be the regulation of gene expression in response to extracellular signals or as part of specific developmental processes. In addition, the MAPK cascades often appear to regulate the cell cycle and vice versa. Despite the success of the gene hunter era in revealing these pathways, there are still many significant gaps in our knowledge of the molecular mechanisms for activation of these cascades and how the cascades regulate cell function. For example, comparison of different yeast signaling pathways reveals a surprising variety of different types of upstream signaling proteins that function to activate a MAPK cascade, yet how the upstream proteins actually activate the cascade remains unclear. We also know that the yeast MAPK pathways regulate each other and interact with other signaling pathways to produce a coordinated pattern of gene expression, but the molecular mechanisms of this cross talk are poorly understood. This review is therefore an attempt to present the current knowledge of MAPK pathways in yeast and some directions for future research in this area.

  12. Biosynthesis of diphthamide in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Chen, J.Y.C.

    1985-01-01

    Inactivation of EF-2 by diphtheria toxin requires the presence of a posttranslationally synthesized amino acid residue, diphthamide. The present work was undertaken to study the biosynthetic mechanism of diphthamide synthesis in the yeast Saccharomyces cerevisiae in order to gain better understanding of the biological roles of this unique amino acid residue. Thirty-one haploid ADP-ribosylation-negative mutants, comprising 5 complementation groups, were obtained. One of these mutants contains a toxin-resistant form of EF-2 which can be converted to a toxin-sensitive form through the methylation reaction catalyzed by a S-AdoMet:EF-2 methyltransferase enzyme which is present in other yeast strains. The [ 3 He]methylated residue in the EF-2 modified by the methyltransferase in the presence of S-Ado-L-[ 3 H-methyl]-Met has been analyzed chromatographically following both acid and enzymatic hydrolysis. At the conclusion of the reaction, all of the radiolabel was recovered as diphthine (the unamidated form of diphthamide). The authors conclude that the S-AdoMet:EF-2-methyltransferase is specific for the addition of at least the last two of the three methyl groups present in diphthine

  13. [Saccharomyces cerevisiae invasive infection: The first reported case in Morocco].

    Science.gov (United States)

    Maleb, A; Sebbar, E; Frikh, M; Boubker, S; Moussaoui, A; El Mekkaoui, A; Khannoussi, W; Kharrasse, G; Belefquih, B; Lemnouer, A; Ismaili, Z; Elouennass, M

    2017-06-01

    Saccharomyces cerevisiae is a cosmopolitan yeast, widely used in agro-alimentary and pharmaceutical industry. Its impact in human pathology is rare, but maybe still underestimated compared to the real situation. This yeast is currently considered as an emerging and opportunistic pathogen. Risk factors are immunosuppression and intravascular device carrying. Fungemias are the most frequent clinical forms. We report the first case of S. cerevisiae invasive infection described in Morocco, and to propose a review of the literature cases of S. cerevisiae infections described worldwide. A 77-year-old patient, with no notable medical history, who was hospitalized for a upper gastrointestinal stenosis secondary to impassable metastatic gastric tumor. Its history was marked by the onset of septic shock, with S. cerevisiae in his urine and in his blood, with arguments for confirmation of invasion: the presence of several risk factors in the patient, positive direct microbiological examination, abundant and exclusive culture of S. cerevisiae from clinical samples. Species identification was confirmed by the study of biochemical characteristics of the isolated yeast. Confirmation of S. cerevisiae infection requires a clinical suspicion in patients with risk factors, but also a correct microbiological diagnosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  14. Identification of genes affecting vacuole membrane fragmentation in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Lydie Michaillat

    Full Text Available The equilibrium of membrane fusion and fission influences the volume and copy number of organelles. Fusion of yeast vacuoles has been well characterized but their fission and the mechanisms determining vacuole size and abundance remain poorly understood. We therefore attempted to systematically characterize factors necessary for vacuole fission. Here, we present results of an in vivo screening for deficiencies in vacuolar fragmentation activity of an ordered collection deletion mutants, representing 4881 non-essential genes of the yeast Saccharomyces cerevisiae. The screen identified 133 mutants with strong defects in vacuole fragmentation. These comprise numerous known fragmentation factors, such as the Fab1p complex, Tor1p, Sit4p and the V-ATPase, thus validating the approach. The screen identified many novel factors promoting vacuole fragmentation. Among those are 22 open reading frames of unknown function and three conspicuous clusters of proteins with known function. The clusters concern the ESCRT machinery, adaptins, and lipases, which influence the production of diacylglycerol and phosphatidic acid. A common feature of these factors of known function is their capacity to change membrane curvature, suggesting that they might promote vacuole fragmentation via this property.

  15. Biosynthesis and engineering of kaempferol in Saccharomyces cerevisiae.

    Science.gov (United States)

    Duan, Lijin; Ding, Wentao; Liu, Xiaonan; Cheng, Xiaozhi; Cai, Jing; Hua, Erbing; Jiang, Huifeng

    2017-09-26

    Kaempferol is a flavonol with broad bioactivity of anti-oxidant, anti-cancer, anti-diabetic, anti-microbial, cardio-protective and anti-asthma. Microbial synthesis of kaempferol is a promising strategy because of the low content in primary plant source. In this study, the biosynthesis pathway of kaempferol was constructed in the budding yeast Saccharomyces cerevisiae to produce kaempferol de novo, and several biological measures were taken for high production. Firstly, a high efficient flavonol synthases (FLS) from Populus deltoides was introduced into the biosynthetic pathway of kaempferol. Secondly, a S. cerevisiae recombinant was constructed for de novo synthesis of kaempferol, which generated about 6.97 mg/L kaempferol from glucose. To further promote kaempferol production, the acetyl-CoA biosynthetic pathway was overexpressed and p-coumarate was supplied as substrate, which improved kaempferol titer by about 23 and 120%, respectively. Finally, a fed-batch process was developed for better kaempferol fermentation performance, and the production reached 66.29 mg/L in 40 h. The titer of kaempferol in our engineered yeast is 2.5 times of the highest reported titer. Our study provides a possible strategy to produce kaempferol using microbial cell factory.

  16. Sucrose and Saccharomyces cerevisiae: a relationship most sweet.

    Science.gov (United States)

    Marques, Wesley Leoricy; Raghavendran, Vijayendran; Stambuk, Boris Ugarte; Gombert, Andreas Karoly

    2016-02-01

    Sucrose is an abundant, readily available and inexpensive substrate for industrial biotechnology processes and its use is demonstrated with much success in the production of fuel ethanol in Brazil. Saccharomyces cerevisiae, which naturally evolved to efficiently consume sugars such as sucrose, is one of the most important cell factories due to its robustness, stress tolerance, genetic accessibility, simple nutrient requirements and long history as an industrial workhorse. This minireview is focused on sucrose metabolism in S. cerevisiae, a rather unexplored subject in the scientific literature. An analysis of sucrose availability in nature and yeast sugar metabolism was performed, in order to understand the molecular background that makes S. cerevisiae consume this sugar efficiently. A historical overview on the use of sucrose and S. cerevisiae by humans is also presented considering sugarcane and sugarbeet as the main sources of this carbohydrate. Physiological aspects of sucrose consumption are compared with those concerning other economically relevant sugars. Also, metabolic engineering efforts to alter sucrose catabolism are presented in a chronological manner. In spite of its extensive use in yeast-based industries, a lot of basic and applied research on sucrose metabolism is imperative, mainly in fields such as genetics, physiology and metabolic engineering. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Proteasome dynamics between proliferation and quiescence stages of Saccharomyces cerevisiae.

    Science.gov (United States)

    Yedidi, Ravikiran S; Fatehi, Amatullah K; Enenkel, Cordula

    The ubiquitin-proteasome system (UPS) plays a critical role in cellular protein homeostasis and is required for the turnover of short-lived and unwanted proteins, which are targeted by poly-ubiquitination for degradation. Proteasome is the key protease of UPS and consists of multiple subunits, which are organized into a catalytic core particle (CP) and a regulatory particle (RP). In Saccharomyces cerevisiae, proteasome holo-enzymes are engaged in degrading poly-ubiquitinated substrates and are mostly localized in the nucleus during cell proliferation. While in quiescence, the RP and CP are sequestered into motile and reversible storage granules in the cytoplasm, called proteasome storage granules (PSGs). The reversible nature of PSGs allows the proteasomes to be transported back into the nucleus upon exit from quiescence. Nuclear import of RP and CP through nuclear pores occurs via the canonical pathway that includes the importin-αβ heterodimer and takes advantage of the Ran-GTP gradient across the nuclear membrane. Dependent on the growth stage, either inactive precursor complexes or mature holo-enzymes are imported into the nucleus. The present review discusses the dynamics of proteasomes including their assembly, nucleo-cytoplasmic transport during proliferation and the sequestration of proteasomes into PSGs during quiescence. [Formula: see text].

  18. Osmo-, thermo- and ethanol- tolerances of Saccharomyces cerevisiae S1

    Directory of Open Access Journals (Sweden)

    Sandrasegarampillai Balakumar

    2012-03-01

    Full Text Available Saccharomyces cerevisiae S1, which is a locally isolated and improved strain showed viability at 40, 45 and 50ºC and produced ethanol at 40, 43 and 45ºC. When the cells were given heat shock at 45ºC for 30min and grown at 40ºC, 100% viability was observed for 60h, and addition of 200gl-1 ethanol has led to complete cell death at 30h. Heat shock given at 45ºC (for 30min has improved the tolerance to temperature induced ethanol shock leading to 37% viability at 30h. when the cells were subjected to ethanol (200gl-1 for 30 min and osmotic shock (sorbitol 300gl-1, trehalose contents in the cells were increased. The heat shocked cells showed better viability in presence of added ethanol. Soy flour supplementation has improved the viability of S. cerevisiae S1 to 80% in presence of 100gl-1 added ethanol and to 60% in presence of 300gl-1 sorbitol. In presence of sorbitol (200gl-1 and ethanol (50gl-1 at 40ºC, 46% viability was retained by S. cerevisiae S1 at 48h and it was improved to 80% by soy flour supplementation.

  19. Degradation signals for ubiquitin system proteolysis in Saccharomyces cerevisiae.

    Science.gov (United States)

    Gilon, T; Chomsky, O; Kulka, R G

    1998-01-01

    Combinations of different ubiquitin-conjugating (Ubc) enzymes and other factors constitute subsidiary pathways of the ubiquitin system, each of which ubiquitinates a specific subset of proteins. There is evidence that certain sequence elements or structural motifs of target proteins are degradation signals which mark them for ubiquitination by a particular branch of the ubiquitin system and for subsequent degradation. Our aim was to devise a way of searching systematically for degradation signals and to determine to which ubiquitin system subpathways they direct the proteins. We have constructed two reporter gene libraries based on the lacZ or URA3 genes which, in Saccharomyces cerevisiae, express fusion proteins with a wide variety of C-terminal extensions. From these, we have isolated clones producing unstable fusion proteins which are stabilized in various ubc mutants. Among these are 10 clones whose products are stabilized in ubc6, ubc7 or ubc6ubc7 double mutants. The C-terminal extensions of these clones, which vary in length from 16 to 50 amino acid residues, are presumed to contain degradation signals channeling proteins for degradation via the UBC6 and/or UBC7 subpathways of the ubiquitin system. Some of these C-terminal tails share similar sequence motifs, and a feature common to almost all of these sequences is a highly hydrophobic region such as is usually located inside globular proteins or inserted into membranes. PMID:9582269

  20. Ubiquitin regulates TORC1 in yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Hu, Kejin; Guo, Shuguang; Yan, Gonghong; Yuan, Wenjie; Zheng, Yin; Jiang, Yu

    2016-04-01

    In the yeast Saccharomyces cerevisiae the TOR complex 1 (TORC1) controls many growth-related cellular processes and is essential for cell growth and proliferation. Macrolide antibiotic rapamycin, in complex with a cytosol protein named FKBP12, specifically inhibits TORC1, causing growth arrest. The FKBP12-rapamycin complex interferes with TORC1 function by binding to the FRB domain of the TOR proteins. In an attempt to understand the role of the FRB domain in TOR function, we identified a single point mutation (Tor2(W2041R) ) in the FRB domain of Tor2 that renders yeast cells rapamycin resistant and temperature sensitive. At the permissive temperature, the Tor2 mutant protein is partially defective for binding with Kog1 and TORC1 is impaired for membrane association. At the restrictive temperature, Kog1 but not the Tor2 mutant protein, is rapidly degraded. Overexpression of ubiquitin stabilizes Kog1 and suppresses the growth defect associated with the tor2 mutant at the nonpremissive temperature. We find that ubiquitin binds non-covalently to Kog1, prevents Kog1 from degradation and stabilizes TORC1. Our data reveal a unique role for ubiquitin in regulation of TORC1 and suggest that Kog1 requires association with the Tor proteins for stabilization. © 2016 John Wiley & Sons Ltd.

  1. Phosphatidylcholine Supply to Peroxisomes of the Yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Flis, Vid V; Fankl, Ariane; Ramprecht, Claudia; Zellnig, Günther; Leitner, Erich; Hermetter, Albin; Daum, Günther

    2015-01-01

    In the yeast Saccharomyces cerevisiae, phosphatidylcholine (PC), the major phospholipid (PL) of all organelle membranes, is synthesized via two different pathways. Methylation of phosphatidylethanolamine (PE) catalyzed by the methyl transferases Cho2p/Pem1p and Opi3p/Pem2p as well as incorporation of choline through the CDP (cytidine diphosphate)-choline branch of the Kennedy pathway lead to PC formation. To determine the contribution of these two pathways to the supply of PC to peroxisomes (PX), yeast mutants bearing defects in the two pathways were cultivated under peroxisome inducing conditions, i.e. in the presence of oleic acid, and subjected to biochemical and cell biological analyses. Phenotype studies revealed compromised growth of both the cho20Δopi3Δ (mutations in the methylation pathway) and the cki1Δdpl1Δeki1Δ (mutations in the CDP-choline pathway) mutant when grown on oleic acid. Analysis of peroxisomes from the two mutant strains showed that both pathways produce PC for the supply to peroxisomes, although the CDP-choline pathway seemed to contribute with higher efficiency than the methylation pathway. Changes in the peroxisomal lipid pattern of mutants caused by defects in the PC biosynthetic pathways resulted in changes of membrane properties as shown by anisotropy measurements with fluorescent probes. In summary, our data define the origin of peroxisomal PC and demonstrate the importance of PC for peroxisome membrane formation and integrity.

  2. Damage-induced ectopic recombination in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Kupiec, M; Steinlauf, R

    1997-06-09

    Mitotic recombination in the yeast Saccharomyces cerevisiae is induced when cells are irradiated with UV or X-rays, reflecting the efficient repair of damage by recombinational repair mechanisms. We have used multiply marked haploid strains that allow the simultaneous detection of several types of ectopic recombination events. We show that inter-chromosomal ectopic conversion of lys2 heteroalleles and, to a lesser extent, direct repeat recombination (DRR) between non-tandem repeats, are increased by DNA-damaging agents; in contrast, ectopic recombination of the naturally occurring Ty element is not induced. We have tested several hypotheses that could explain the preferential lack of induction of Ty recombination by DNA-damaging agents. We have found that the lack of induction cannot be explained by a cell cycle control or by an effect of the mating-type genes. We also found no role for the flanking long terminal repeats (LTRs) of the Ty in preventing the induction. Ectopic conversion, DRR, and forward mutation of artificial repeats show different kinetics of induction at various positions of the cell cycle, reflecting different mechanisms of recombination. We discuss the mechanistic and evolutionary aspects of these results.

  3. Modifications of Saccharomyces pastorianus cell wall polysaccharides with brewing process.

    Science.gov (United States)

    Bastos, Rita; Coelho, Elisabete; Coimbra, Manuel A

    2015-06-25

    The cell wall polysaccharides of brewers spent yeast Saccharomyces pastorianus (BSY) and the inoculum yeast (IY) were studied in order to understand the changes induced by the brewing process. The hot water and alkali extractions performed solubilized mainly mannoproteins, more branched for BSY than those of IY. Also, (31)P solid state NMR showed that the BSY mannoproteins were 3 times more phosphorylated. By electron microscopy it was observed that the final residues of alkali sequential extraction until 4M KOH preserved the yeast three-dimensional structure. The final residues, composed mainly by glucans (92%), showed that the BSY, when compared with IY, contained higher amount of (1→4)-linked Glc (43% for BSY and 16% for IY) and lower (1→3)-linked Glc (17% for BSY and 42% for IY). The enzymatic treatment of final residue showed that both BSY and IY had (α1→4)-linked Glc and (β1→4)-linked Glc, in a 2:1 ratio, showing that S. pastorianus increases their cellulose-like linkages with the brewing process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

    Directory of Open Access Journals (Sweden)

    Hana Šuranská

    2016-03-01

    Full Text Available Abstract In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were employed to differentiate among indigenous S. cerevisiae strains. This combination of the methods provides a rapid and relatively simple approach for identification of yeast of S. cerevisiae at strain level. In total, 120 isolates were identified and grouped by molecular approaches and 45 of the representative strains were tested for selected important oenological properties including ethanol, sulfur dioxide and osmotic stress tolerance, intensity of flocculation and desirable enzymatic activities. Their ability to produce and utilize acetic/malic acid was examined as well; in addition, H2S production as an undesirable property was screened. The oenological characteristics of indigenous isolates were compared to a commercially available S. cerevisiae BS6 strain, which is commonly used as the starter culture. Finally, some indigenous strains coming from organically treated grape berries were chosen for their promising oenological properties and these strains will be used as the starter culture, because application of a selected indigenous S. cerevisiae strain can enhance the regional character of the wines.

  5. Effects of low X-ray doses in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Jordan, A.; Laskowski, W.

    1987-01-01

    Three strains of Saccharomyces cerevisiae with different capacities for repair of radiation damage (RAD, rad18, and rad52) have been tested for their colony forming ability (CFA) and growth rates after application of small X-ray doses from 3.8 mGy to 40 Gy. There was no reproducible increase in CFA observable after application of doses between 3.8 mGy and 4.7 Gy.X-ray doses of 40 Gy causing an inactivation of CFA from 90% to 50%, depending on the repair capacity of the strains used, caused a reduced increase in optical density during 2 h buffer treatment in comparison to unirradiated cells. This reduction however, is reversible as soon as the cells are transferred into nutrient medium. One hour after transfer into growh medium the portions of cells with large buds (Gs and M phase) and cells with small buds (S phase) are drastically different in irradiated cells from those obtained in unirradiated cells. The time necessary for separation of mother and daughter cells is prolonged by X-ray irradiation and the formation of new buds is retarded. (orig.)

  6. Early manifestations of replicative aging in the yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Maksim I. Sorokin

    2014-01-01

    Full Text Available The yeast Saccharomyces cerevisiae is successfully used as a model organism to find genes responsible for lifespan control of higher organisms. As functional decline of higher eukaryotes can start as early as one quarter of the average lifespan, we asked whether S. cerevisiae can be used to model this manifestation of aging. While the average replicative lifespan of S. cerevisiae mother cells ranges between 15 and 30 division cycles, we found that resistances to certain stresses start to decrease much earlier. Looking into the mechanism, we found that knockouts of genes responsible for mitochondriato-nucleus (retrograde signaling, RTG1 or RTG3, significantly decrease the resistance of cells that generated more than four daughters, but not of the younger ones. We also found that even young mother cells frequently contain mitochondria with heterogeneous transmembrane potential and that the percentage of such cells correlates with replicative age. Together, these facts suggest that retrograde signaling starts to malfunction in relatively young cells, leading to accumulation of heterogeneous mitochondria within one cell. The latter may further contribute to a decline in stress resistances.

  7. Lactose fermentation by engineered Saccharomyces cerevisiae capable of fermenting cellobiose.

    Science.gov (United States)

    Liu, Jing-Jing; Zhang, Guo-Chang; Oh, Eun Joong; Pathanibul, Panchalee; Turner, Timothy L; Jin, Yong-Su

    2016-09-20

    Lactose is an inevitable byproduct of the dairy industry. In addition to cheese manufacturing, the growing Greek yogurt industry generates excess acid whey, which contains lactose. Therefore, rapid and efficient conversion of lactose to fuels and chemicals would be useful for recycling the otherwise harmful acid whey. Saccharomyces cerevisiae, a popular metabolic engineering host, cannot natively utilize lactose. However, we discovered that an engineered S. cerevisiae strain (EJ2) capable of fermenting cellobiose can also ferment lactose. This finding suggests that a cellobiose transporter (CDT-1) can transport lactose and a β-glucosidase (GH1-1) can hydrolyze lactose by acting as a β-galactosidase. While the lactose fermentation by the EJ2 strain was much slower than the cellobiose fermentation, a faster lactose-fermenting strain (EJ2e8) was obtained through serial subcultures on lactose. The EJ2e8 strain fermented lactose with a consumption rate of 2.16g/Lh. The improved lactose fermentation by the EJ2e8 strain was due to the increased copy number of cdt-1 and gh1-1 genes. Looking ahead, the EJ2e8 strain could be exploited for the production of other non-ethanol fuels and chemicals from lactose through further metabolic engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Seven cases of Saccharomyces fungaemia related to use of probiotics.

    Science.gov (United States)

    Roy, Ujjwayini; Jessani, Laxman G; Rudramurthy, Shivaprakash M; Gopalakrishnan, Ram; Dutta, Soma; Chakravarty, Chandrashish; Jillwin, Joseph; Chakrabarti, Arunaloke

    2017-06-01

    Probiotics are increasingly used in critically ill patients without enough safety data. The aim of the present study was to determine the association of probiotics with Saccharomyces cerevisiae fungaemia. Seven patients with S. cerevisiae fungaemia were reported at two hospitals in India between July 2014 and September 2015. Detailed clinical history of patients was recorded. Besides the seven patient isolates, three probiotics sachets used in those patients and five unrelated clinical isolates were used for association study by Fluorescent amplified fragment length polymorphism (FAFLP). Antifungal susceptibility testing was performed by broth microdilution technique of CLSI (M27-A3) and interpreted according to CLSI (M27S4). Two patients were premature neonates and five were adults. They were admitted in intensive care unit and were on probiotics containing S. boulardii (except one adult patient). FAFLP analysis showed 96.4-99.7% similarity between blood and corresponding probiotic isolates. Of the three AFLP types (group I, II, II) identified, all the probiotic isolates clustered in group I (major cluster) including majority of the blood isolates. The isolates were susceptible to all antifungal agents tested. Five patients, who could be evaluated, responded promptly to echinocandins or voriconazole. As the prescription of probiotic containing S. boulardii in critically ill patient's leads to the fungaemia, we recommend avoiding this probiotic in those patients. © 2017 Blackwell Verlag GmbH.

  9. Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

    Science.gov (United States)

    Orlean, Peter

    2012-01-01

    The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. PMID:23135325

  10. Intracellular metabolite profiling of Saccharomyces cerevisiae evolved under furfural.

    Science.gov (United States)

    Jung, Young Hoon; Kim, Sooah; Yang, Jungwoo; Seo, Jin-Ho; Kim, Kyoung Heon

    2017-03-01

    Furfural, one of the most common inhibitors in pre-treatment hydrolysates, reduces the cell growth and ethanol production of yeast. Evolutionary engineering has been used as a selection scheme to obtain yeast strains that exhibit furfural tolerance. However, the response of Saccharomyces cerevisiae to furfural at the metabolite level during evolution remains unknown. In this study, evolutionary engineering and metabolomic analyses were applied to determine the effects of furfural on yeasts and their metabolic response to continuous exposure to furfural. After 50 serial transfers of cultures in the presence of furfural, the evolved strains acquired the ability to stably manage its physiological status under the furfural stress. A total of 98 metabolites were identified, and their abundance profiles implied that yeast metabolism was globally regulated. Under the furfural stress, stress-protective molecules and cofactor-related mechanisms were mainly induced in the parental strain. However, during evolution under the furfural stress, S. cerevisiae underwent global metabolic allocations to quickly overcome the stress, particularly by maintaining higher levels of metabolites related to energy generation, cofactor regeneration and recovery from cellular damage. Mapping the mechanisms of furfural tolerance conferred by evolutionary engineering in the present study will be led to rational design of metabolically engineered yeasts. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  11. Xylose Fermentation by Saccharomyces cerevisiae: Challenges and Prospects

    Directory of Open Access Journals (Sweden)

    Danuza Nogueira Moysés

    2016-02-01

    Full Text Available Many years have passed since the first genetically modified Saccharomyces cerevisiae strains capable of fermenting xylose were obtained with the promise of an environmentally sustainable solution for the conversion of the abundant lignocellulosic biomass to ethanol. Several challenges emerged from these first experiences, most of them related to solving redox imbalances, discovering new pathways for xylose utilization, modulation of the expression of genes of the non-oxidative pentose phosphate pathway, and reduction of xylitol formation. Strategies on evolutionary engineering were used to improve fermentation kinetics, but the resulting strains were still far from industrial application. Lignocellulosic hydrolysates proved to have different inhibitors derived from lignin and sugar degradation, along with significant amounts of acetic acid, intrinsically related with biomass deconstruction. This, associated with pH, temperature, high ethanol, and other stress fluctuations presented on large scale fermentations led the search for yeasts with more robust backgrounds, like industrial strains, as engineering targets. Some promising yeasts were obtained both from studies of stress tolerance genes and adaptation on hydrolysates. Since fermentation times on mixed-substrate hydrolysates were still not cost-effective, the more selective search for new or engineered sugar transporters for xylose are still the focus of many recent studies. These challenges, as well as under-appreciated process strategies, will be discussed in this review.

  12. Mead production: selection and characterization assays of Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Pereira, Ana Paula; Dias, Teresa; Andrade, João; Ramalhosa, Elsa; Estevinho, Letícia M

    2009-08-01

    Mead is a traditional drink, which results from the alcoholic fermentation of diluted honey carried out by yeasts. However, when it is produced in a homemade way, mead producers find several problems, namely, the lack of uniformity in the final product, delayed and arrested fermentations, and the production of "off-flavours" by the yeasts. These problems are usually associated with the inability of yeast strains to respond and adapt to unfavourable and stressful growth conditions. The main objectives of this work were to evaluate the capacity of Saccharomyces cerevisiae strains, isolated from honey of the Trás-os-Montes (Northeast Portugal), to produce mead. Five strains from honey, as well as one laboratory strain and one commercial wine strain, were evaluated in terms of their fermentation performance under ethanol, sulphur dioxide and osmotic stress. All the strains showed similar behaviour in these conditions. Two yeasts strains isolated from honey and the commercial wine strain were further tested for mead production, using two different honey (a dark and a light honey), enriched with two supplements (one commercial and one developed by the research team), as fermentation media. The results obtained in this work show that S. cerevisiae strains isolated from honey, are appropriate for mead production. However it is of extreme importance to take into account the characteristics of the honey, and supplements used in the fermentation medium formulation, in order to achieve the best results in mead production.

  13. Genomic Evolution of Saccharomyces cerevisiae under Chinese Rice Wine Fermentation

    Science.gov (United States)

    Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

    2014-01-01

    Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. PMID:25212861

  14. Metabolic engineering of Saccharomyces cerevisiae for caffeine and theobromine production.

    Directory of Open Access Journals (Sweden)

    Lu Jin

    Full Text Available Caffeine (1, 3, 7-trimethylxanthine and theobromine (3, 7-dimethylxanthine are the major purine alkaloids in plants, e.g., tea (Camellia sinensis and coffee (Coffea arabica. Caffeine is a major component of coffee and is used widely in food and beverage industries. Most of the enzymes involved in the caffeine biosynthetic pathway have been reported previously. Here, we demonstrated the biosynthesis of caffeine (0.38 mg/L by co-expression of Coffea arabica xanthosine methyltransferase (CaXMT and Camellia sinensis caffeine synthase (TCS in Saccharomyces cerevisiae. Furthermore, we endeavored to develop this production platform for making other purine-based alkaloids. To increase the catalytic activity of TCS in an effort to increase theobromine production, we identified four amino acid residues based on structural analyses of 3D-model of TCS. Two TCS1 mutants (Val317Met and Phe217Trp slightly increased in theobromine accumulation and simultaneously decreased in caffeine production. The application and further optimization of this biosynthetic platform are discussed.

  15. Metabolic engineering of Saccharomyces cerevisiae for caffeine and theobromine production.

    Science.gov (United States)

    Jin, Lu; Bhuiya, Mohammad Wadud; Li, Mengmeng; Liu, XiangQi; Han, Jixiang; Deng, WeiWei; Wang, Min; Yu, Oliver; Zhang, Zhengzhu

    2014-01-01

    Caffeine (1, 3, 7-trimethylxanthine) and theobromine (3, 7-dimethylxanthine) are the major purine alkaloids in plants, e.g., tea (Camellia sinensis) and coffee (Coffea arabica). Caffeine is a major component of coffee and is used widely in food and beverage industries. Most of the enzymes involved in the caffeine biosynthetic pathway have been reported previously. Here, we demonstrated the biosynthesis of caffeine (0.38 mg/L) by co-expression of Coffea arabica xanthosine methyltransferase (CaXMT) and Camellia sinensis caffeine synthase (TCS) in Saccharomyces cerevisiae. Furthermore, we endeavored to develop this production platform for making other purine-based alkaloids. To increase the catalytic activity of TCS in an effort to increase theobromine production, we identified four amino acid residues based on structural analyses of 3D-model of TCS. Two TCS1 mutants (Val317Met and Phe217Trp) slightly increased in theobromine accumulation and simultaneously decreased in caffeine production. The application and further optimization of this biosynthetic platform are discussed.

  16. ORGANIC ACIDS CONCENTRATION IN WINE STOCKS AFTER Saccharomyces cerevisiae FERMENTATION

    Directory of Open Access Journals (Sweden)

    V. N. Bayraktar

    2013-04-01

    Full Text Available The biochemical constituents in wine stocks that influence the flavor and quality of wine are investigated in the paper. The tested parameters consist of volume fraction of ethanol, residual sugar, phenolic compounds, tartaric, malic, citric, lactic, acetic acids, titratable acidity and volatile acids. The wine stocks that were received from white and red grape varieties Tairov`s selection were tested. There was a correlation between titratable acidity and volatile acids in the wine stocks from white and red grape varieties. High correlation was also found between lactic and acetic acids, between volatile acids, acetic acid and sugar. It was determined that wine stocks with a high concentration of ethanol originated from those yeast strains of Saccharomyces cerevisiae, in a fermented grape must of high speed of enzyme activity. The taste of wine stocks correlated with the ratio of tartaric to malic acid. Analysis showed significant differences between the varieties of white and red wine stocks in concentrations of organic acids, phenolic compounds, residual sugar, and volume fraction of ethanol. Positive correlation was indicated for both studied groups for volatile acids and acetic acid, tartaric, malic, lactic acids and total sugar. Prospective yeast cultures with high productivity of alcohol (ethanol were selected for winemaking biotechnology.

  17. Anti-hypercholesterolemic effect of Saccharomyces boulardii in the hamster.

    Science.gov (United States)

    Girard, Philippe; Pansart, Yannick; Verleye, Marc

    2014-01-01

    Hypercholesterolemia is a major risk factor for coronary artery disease and probiotics have been suggested as tools to manage elevated cholesterol levels. The present study investigated the ability of the biotherapeutic agent Saccharomyces boulardii (Sb-Biocodex) to reduce the hypercholesterolemia induced by a 0.1% cholesterol-enriched diet in the hamster. In a first experiment, chronic oral treatment with S. boulardii at 12 × 10(10) CFU/kg (3 g/kg) twice a day was started from the beginning of the cholesterol diet and continued for 14 days ('preventive protocol'). In the second experiment, S. boulardii was given 14 days after the beginning of the cholesterol diet when hypercholesterolemia had developed and continued for an additional 14 days ('curative protocol'). In the preventive protocol, administration of the yeast significantly reduced hypercholesterolemia (14%) induced by the cholesterol-enriched diet compared to the group receiving only the cholesterol diet. In the curative protocol, S. boulardii significantly reduced hypercholesterolemia (12%) induced by the cholesterol-enriched diet, too. Moreover, the yeast significantly decreased the serum triglyceride increase by 39%. S. boulardii possesses anti-hypercholesterolemic properties in the hamster worthy of further evaluation in clinical studies. © 2014 S. Karger AG, Basel.

  18. Saccharomyces boulardii interferes with Shigella pathogenesis by postinvasion signaling events

    Science.gov (United States)

    Mumy, Karen L.; Chen, Xinhua; Kelly, Ciarán P.; McCormick, Beth A.

    2011-01-01

    Saccharomyces boulardii is gaining in popularity as a treatment for a variety of diarrheal diseases as well as inflammatory bowel disease. This study was designed to examine the effect of this yeast on infection by Shigella flexneri, a highly infectious and human host-adapted enteric pathogen. We investigated key interactions between the bacteria and host cells in the presence of the yeast in addition to a number of host responses including proinflammatory events and markers. Although the presence of the yeast during infection did not alter the number of bacteria that was able to attach or invade human colon cancer-derived T-84 cells, it did positively impact the tight junction protein zonula occluden-2 and significantly increase the barrier integrity of model epithelia. The yeast also decreased ERK, JNK, and NF-κB activation in response to S. flexneri, events likely responsible for the observed reductions in IL-8 secretion and the transepithelial migration of polymorphonuclear leukocytes across T-84 monolayers. These results, suggesting that the yeast allowed for a dampened inflammatory response, were confirmed in vivo utilizing a highly relevant model of human fetal colonic tissue transplanted into scid mice. Furthermore, a cell-free S. boulardii culture supernatant was also capable of reducing IL-8 secretion by infected T-84 cells. These data suggest that although the use of S. boulardii during infection with S. flexneri may alleviate symptoms associated with the inflammatory response of the host, it would not prevent infection. PMID:18032477

  19. Treatment of acute diarrhea with Saccharomyces boulardii in infants.

    Science.gov (United States)

    Corrêa, Naflesia B O; Penna, Francisco J; Lima, Fátima M L S; Nicoli, Jacques R; Filho, Luciano A P

    2011-11-01

    The aim of the study was to determine whether an oral treatment with a commercial pharmaceutical product containing Saccharomyces boulardii would reduce the duration of diarrhea in infants with acute diarrhea. In the present double-blind, placebo-controlled study, 186 infants, 6 to 48 months old and hospitalized within 72 hours after the onset of acute diarrhea in 2 hospitals in Goiânia, Goiás, Brazil, were randomly assigned to receive twice per day for 5 days 200 mg of a commercial pharmaceutical product containing 4 × 10 viable cells of S boulardii or a placebo. Stool samples were submitted to search for rotavirus. Among the 176 infants who completed the trial, those treated with S boulardii (90) showed a reduction in diarrhea duration (P boulardii was given to children within 72 hours after the onset of acute diarrhea. The present study suggests a complementary treatment of acute diarrhea in infants with daily oral doses of S boulardii.

  20. Calcium dependence of eugenol tolerance and toxicity in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Stephen K Roberts

    Full Text Available Eugenol is a plant-derived phenolic compound which has recognised therapeutical potential as an antifungal agent. However little is known of either its fungicidal activity or the mechanisms employed by fungi to tolerate eugenol toxicity. A better exploitation of eugenol as a therapeutic agent will therefore depend on addressing this knowledge gap. Eugenol initiates increases in cytosolic Ca2+ in Saccharomyces cerevisiae which is partly dependent on the plasma membrane calcium channel, Cch1p. However, it is unclear whether a toxic cytosolic Ca2+elevation mediates the fungicidal activity of eugenol. In the present study, no significant difference in yeast survival was observed following transient eugenol treatment in the presence or absence of extracellular Ca2+. Furthermore, using yeast expressing apoaequorin to report cytosolic Ca2+ and a range of eugenol derivatives, antifungal activity did not appear to be coupled to Ca2+ influx or cytosolic Ca2+ elevation. Taken together, these results suggest that eugenol toxicity is not dependent on a toxic influx of Ca2+. In contrast, careful control of extracellular Ca2+ (using EGTA or BAPTA revealed that tolerance of yeast to eugenol depended on Ca2+ influx via Cch1p. These findings expose significant differences between the antifungal activity of eugenol and that of azoles, amiodarone and carvacrol. This study highlights the potential to use eugenol in combination with other antifungal agents that exhibit differing modes of action as antifungal agents to combat drug resistant infections.

  1. Ethylene production in relation to nitrogen metabolism in Saccharomyces cerevisiae.

    Science.gov (United States)

    Johansson, Nina; Persson, Karl O; Quehl, Paul; Norbeck, Joakim; Larsson, Christer

    2014-11-01

    We have previously shown that ethylene production in Saccharomyces cerevisiae expressing the ethylene-forming enzyme (EFE) from Pseudomonas syringae is strongly influenced by variations in the mode of cultivation as well as the choice of nitrogen source. Here, we have studied the influence of nitrogen metabolism on the production of ethylene further. Using ammonium, glutamate, glutamate/arginine, and arginine as nitrogen sources, it was found that glutamate (with or without arginine) correlates with a high ethylene production, most likely linked to an observed increase in 2-oxoglutarate levels. Arginine as a sole nitrogen source caused a reduced ethylene production. A reduction of arginine levels, accomplished using an arginine auxotrophic ARG4-deletion strain in the presence of limiting amounts of arginine or through CAR1 overexpression, did however not correlate with an increased ethylene production. As expected, arginine was necessary for ethylene production as ethylene production in the ARG4-deletion strain ceased at the time when arginine was depleted. In conclusion, our data suggest that high levels of 2-oxoglutarate and a limited amount of arginine are required for successful ethylene production in yeast. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  2. Saccharomyces cerevisiae in the Production of Whisk(ey

    Directory of Open Access Journals (Sweden)

    Graeme M. Walker

    2016-12-01

    Full Text Available Whisk(ey is a major global distilled spirit beverage. Whiskies are produced from cereal starches that are saccharified, fermented and distilled prior to spirit maturation. The strain of Saccharomyces cerevisiae employed in whisky fermentations is crucially important not only in terms of ethanol yields, but also for production of minor yeast metabolites which collectively contribute to development of spirit flavour and aroma characteristics. Distillers must therefore pay very careful attention to the strain of yeast exploited to ensure consistency of fermentation performance and spirit congener profiles. In the Scotch whisky industry, initiatives to address sustainability issues facing the industry (for example, reduced energy and water usage have resulted in a growing awareness regarding criteria for selecting new distilling yeasts with improved efficiency. For example, there is now a desire for Scotch whisky distilling yeasts to perform under more challenging conditions such as high gravity wort fermentations. This article highlights the important roles of S. cerevisiae strains in whisky production (with particular emphasis on Scotch and describes key fermentation performance attributes sought in distiller’s yeast, such as high alcohol yields, stress tolerance and desirable congener profiles. We hope that the information herein will be useful for whisky producers and yeast suppliers in selecting new distilling strains of S. cerevisiae, and for the scientific community to stimulate further research in this area.

  3. Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

    Science.gov (United States)

    Yang, Shih-Chun; Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

    2017-08-01

    Food contamination by pathogenic microorganisms has been a serious public health problem and a cause of huge economic losses worldwide. Foodborne pathogenic Escherichia coli (E. coli) contamination, such as that with E. coli O157 and O104, is very common, even in developed countries. Bacterial contamination may occur during any of the steps in the farm-to-table continuum from environmental, animal, or human sources and cause foodborne illness. To understand the causes of the foodborne outbreaks by E. coli and food-contamination prevention measures, we collected and investigated the past 10 years' worldwide reports of foodborne E. coli contamination cases. In the first half of this review article, we introduce the infection and symptoms of five major foodborne diarrheagenic E. coli pathotypes: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli/enterohemorrhagic E. coli (STEC/EHEC), Shigella/enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC). In the second half of this review article, we introduce the foodborne outbreak cases caused by E. coli in natural foods and food products. Finally, we discuss current developments that can be applied to control and prevent bacterial food contamination.

  4. Action of sodium deoxycholate on Escherichia coli

    International Nuclear Information System (INIS)

    D'Mello, A.; Yotis, W.W.

    1987-01-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of [U- 14 C]glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order

  5. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

    Directory of Open Access Journals (Sweden)

    Tjaša Danevčič

    Full Text Available Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria.

  6. Deuterium incorporation into Escherichia-coli proteins

    DEFF Research Database (Denmark)

    Lederer, H.; May, R. P.; Kjems, Jørgen

    1986-01-01

    Neutron small-angle scattering studies of single protein subunits in a protein-DNA complex require the adjustment of the neutron scattering-length densities of protein and DNA, which is attainable by specific deuteration of the protein. The neutron scattering densities of unlabelled DNA and DNA......-dependent RNA polymerase of Escherichia coli match when RNA polymerase is isolated from cells grown in a medium containing 46% D2O and unlabelled glucose as carbon source. Their contrasts vanish simultaneously in a dialysis buffer containing 65% D2O. An expression was evaluated which allows the calculation...... of the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the degree...

  7. Action of sodium deoxycholate on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    D' Mello, A.; Yotis, W.W.

    1987-08-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

  8. Past and Future of Non-Saccharomyces Yeasts: From Spoilage Microorganisms to Biotechnological Tools for Improving Wine Aroma Complexity

    Science.gov (United States)

    Padilla, Beatriz; Gil, José V.; Manzanares, Paloma

    2016-01-01

    It is well established that non-Saccharomyces wine yeasts, considered in the past as undesired or spoilage yeasts, can enhance the analytical composition, and aroma profile of the wine. The contribution of non-Saccharomyces yeasts, including the ability to secret enzymes and produce secondary metabolites, glycerol and ethanol, release of mannoproteins or contributions to color stability, is species- and strain-specific, pointing out the key importance of a clever strain selection. The use of mixed starters of selected non-Saccharomyces yeasts with strains of Saccharomyces cerevisiae represents an alternative to both spontaneous and inoculated wine fermentations, taking advantage of the potential positive role that non-Saccharomyces wine yeast species play in the organoleptic characteristics of wine. In this context mixed starters can meet the growing demand for new and improved wine yeast strains adapted to different types and styles of wine. With the aim of presenting old and new evidences on the potential of non-Saccharomyces yeasts to address this market trend, we mainly review the studies focused on non-Saccharomyces strain selection and design of mixed starters directed to improve primary and secondary aroma of wines. The ability of non-Saccharomyces wine yeasts to produce enzymes and metabolites of oenological relevance is also discussed. PMID:27065975

  9. Expression and purification of antimicrobial peptide adenoregulin with C-amidated terminus in Escherichia coli.

    Science.gov (United States)

    Cao, Wei; Zhou, Yuxun; Ma, Yushu; Luo, Qingping; Wei, Dongzhi

    2005-04-01

    Adenoregulin is a 33 amino acid antimicrobial peptide isolated from the skin of the arboreal frog Phyllomedusa bicolor. Natural adenoregulin is synthesized with an amidated valine residue at C-terminus and shows lethal effects against filamentous fungi, as well as a broad spectrum of pathogenic microorganisms. A synthetic gene for adenoregulin (ADR) with an additional amino acid glutamine at C-terminus was cloned into pET32a vector to allow expression of ADR as a Trx fusion protein in Escherichia coli BL21(DE3). The resulting expression level of the fusion protein could reach up to 20% of the total cell proteins. The fusion protein could be purified effectively by Ni2+-chelating chromatography. Released from the fusion protein by enterokinase cleavage and purified to homogeneity, the recombinant ADR displayed antimicrobial activity similar to that of the synthetic ADR reported earlier. Comparing the antimicrobial activities of the recombinant adenoregulin with C-amidated terminus to that without an amidated C-terminus, we found that the amide of glutamine at C-terminus of ADR improved its potency on certain microorganisms such as Tritirachium album and Saccharomyces cerevisiae.

  10. Melanosis coli in patients with colon cancer

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    Dorota Biernacka-Wawrzonek

    2016-12-01

    Full Text Available Intoduction: Melanosis coli is a benign lesion affecting the mucosa of the large intestine. There is a relationship between the presence of melanosis and anthraquinone laxative use. Melanosis coli is also observed in patients with colon cancer, but there is doubt whether these two conditions are related. Aim : To analyze the correlation between melanosis and colon cancer. Material and methods: We analyzed retrospectively 436 patients undergoing colon cancer surgery. There were 246 women and 190 men. Patients were divided into three age groups: under 50 years, between 51 and 65 years, and over 66 years. We analyzed sections of the cancer and intestinal mucosa from the tumor’s proximal (2–5 cm and distal (8–10 cm zone. Results : Melanosis coli was present in 52 patients, which represents 11.9% of patients with colon cancer. More often it was present in women. The most common location of melanosis and colon cancer was the terminal part of the large intestine. In patients below 50 years of age in both sexes melanosis coli did not occur. In men, melanosis was more common in the age group over 66 years. Intensity of pigmentation was higher in the tumor’s distal zone. Conclusions : The incidence of melanosis coli increases with age, similar to that of colon cancer. Melanosis was not present inside tumors, in almost half of the cases it was not present in the proximal zone, and the degree of pigmentation increased in distal zone. The cause-effect relationship between melanosis coli and colon cancer remains uncertain.

  11. Hydrogen production by recombinant Escherichia coli strains

    Science.gov (United States)

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Wood, Thomas K.

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  12. Vaginal Lactobacillus isolates inhibit uropathogenic Escherichia coli.

    OpenAIRE

    Atassi , Fabrice; Brassart , Dominique; Grob , Philipp; Graf , Federico; Servin , Alain ,

    2006-01-01

    The purpose of this study was to investigate the antibacterial activities of Lactobacillus jensenii KS119.1 and KS121.1, and Lactobacillus gasserii KS120.1 and KS124.3 strains isolated from the vaginal microflora of healthy women, against uropathogenic, diffusely adhering Afa/Dr Escherichia coli (Afa/Dr DAEC) strains IH11128 and 7372 involved in recurrent cystitis. We observed that some of the Lactobacillus isolates inhibited the growth and decreased the viability of E. coli IH11128 and 7372....

  13. Synthesis of avenanthramides using engineered Escherichia coli.

    Science.gov (United States)

    Lee, Su Jin; Sim, Geun Young; Kang, Hyunook; Yeo, Won Seok; Kim, Bong-Gyu; Ahn, Joong-Hoon

    2018-03-22

    Hydroxycinnamoyl anthranilates, also known as avenanthramides (avns), are a group of phenolic alkaloids with anti-inflammatory, antioxidant, anti-itch, anti-irritant, and antiatherogenic activities. Some avenanthramides (avn A-H and avn K) are conjugates of hydroxycinnamic acids (HC), including p-coumaric acid, caffeic acid, and ferulic acid, and anthranilate derivatives, including anthranilate, 4-hydroxyanthranilate, and 5-hydroxyanthranilate. Avns are primarily found in oat grain, in which they were originally designated as phytoalexins. Knowledge of the avns biosynthesis pathway has now made it possible to synthesize avns through a genetic engineering strategy, which would help to further elucidate their properties and exploit their beneficial biological activities. The aim of the present study was to synthesize natural avns in Escherichia coli to serve as a valuable resource. We synthesized nine avns in E. coli. We first synthesized avn D from glucose in E. coli harboring tyrosine ammonia lyase (TAL), 4-coumarate:coenzyme A ligase (4CL), anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), and anthranilate synthase (trpEG). A trpD deletion mutant was used to increase the amount of anthranilate in E. coli. After optimizing the incubation temperature and cell density, approximately 317.2 mg/L of avn D was synthesized. Avn E and avn F were then synthesized from avn D, using either E. coli harboring HpaBC and SOMT9 or E. coli harboring HapBC alone, respectively. Avn A and avn G were synthesized by feeding 5-hydroxyanthranilate or 4-hydroxyanthranilate to E. coli harboring TAL, 4CL, and HCBT. Avn B, avn C, avn H, and avn K were synthesized from avn A or avn G, using the same approach employed for the synthesis of avn E and avn F from avn D. Using different HCs, nine avns were synthesized, three of which (avn D, avn E, and avn F) were synthesized from glucose in E. coli. These diverse avns provide a strategy to synthesize both natural and unnatural avns

  14. Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Olsen, Katharina E P; Struve, Carsten

    2014-01-01

    Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission...

  15. lactamases genes among0 Escherichia coli from patients with ...

    African Journals Online (AJOL)

    -lactamases (ESBLs) that mediate resistance to b-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with ...

  16. Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli ...

    African Journals Online (AJOL)

    Erah

    PMQR) genes and the prevalence of extended spectrum β-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed ...

  17. Transcriptomic analysis of Saccharomyces cerevisiae x Saccharomyces kudriavzevii hybrids during low temperature winemaking [version 3; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Jordi Tronchoni

    2017-09-01

    Full Text Available Background: Although Saccharomyces cerevisiae is the most frequently isolated species in wine fermentation, and the most studied species, other species and interspecific hybrids have greatly attracted the interest of researchers in this field in the last few years, given their potential to solve new winemaking industry challenges. S. cerevisiae x S. kudriavzevii hybrids exhibit good fermentative capabilities at low temperatures, and produce wines with smaller alcohol quantities and larger glycerol quantities, which can be very useful to solve challenges in the winemaking industry such as the necessity to enhance the aroma profile. Methods: In this study, we performed a transcriptomic study of S. cerevisiae x S. kudriavzevii hybrids in low temperature winemaking conditions. Results: The results revealed that the hybrids have acquired both fermentative abilities and cold adaptation abilities, attributed to S. cerevisiae and S. kudriavzevii parental species, respectively, showcasing their industrially relevant characteristics. For several key genes, we also studied the contribution to gene expression of each of the alleles of S. cerevisiae and S. kudriavzevii in the S. cerevisiae x S. kudriavzevii hybrids. From the results, it is not clear how important the differential expression of the specific parental alleles is to the phenotype of the hybrids. Conclusions: This study shows that the fermentative abilities of S. cerevisiae x S. kudriavzevii hybrids at low temperatures do not seem to result from differential expression of specific parental alleles of the key genes involved in this phenotype.

  18. Ability for anaerobic growth is not sufficient for development of the petite phenotype in Saccharomyces kluyveri

    DEFF Research Database (Denmark)

    Møller, Kasper; Olsson, Lisbeth; Piskur, Jure

    2001-01-01

    Saccharomyces cerevisiae is a petite-phenotype-positive ("petite-positive") yeast, which can successfully grow in the absence of oxygen. On the other hand, Kluyveromyces lactis as well as many other yeasts are petite negative and cannot grow anaerobically. In this paper, we show that Saccharomyces...... kluyveri can grow under anaerobic conditions, but while it can generate respiration-deficient mutants, it cannot generate true petite mutants. From a phylogenetic point of view, S. kluyveri is apparently more closely related to S. cerevisiae than to K. lactis. These observations suggest that the progenitor...... of the modern Saccharomyces and Kluyveromyces yeasts, as well as other related genera, was a petite-negative and aerobic yeast. Upon separation of the K. lactis and S. kluyveri-S. cerevisiae lineages, the latter developed the ability to grow anaerobically. However, while the S. kluyveri lineage has remained...

  19. [High gene conversion frequency between genes encoding 2-deoxyglucose-6-phosphate phosphatase in 3 Saccharomyces species].

    Science.gov (United States)

    Piscopo, Sara-Pier; Drouin, Guy

    2014-05-01

    Gene conversions are nonreciprocal sequence exchanges between genes. They are relatively common in Saccharomyces cerevisiae, but few studies have investigated the evolutionary fate of gene conversions or their functional impacts. Here, we analyze the evolution and impact of gene conversions between the two genes encoding 2-deoxyglucose-6-phosphate phosphatase in S. cerevisiae, Saccharomyces paradoxus and Saccharomyces mikatae. Our results demonstrate that the last half of these genes are subject to gene conversions among these three species. The greater similarity and the greater percentage of GC nucleotides in the converted regions, as well as the absence of long regions of adjacent common converted sites, suggest that these gene conversions are frequent and occur independently in all three species. The high frequency of these conversions probably result from the fact that they have little impact on the protein sequences encoded by these genes.

  20. FREQUENCY AND DISTRIBUTION OF DIARRHOEAGENIC ESCHERICHIA COLI STRAINS ISOLATED FROM PEDIATRIC PATIENTS WITH DIARRHOEA IN BOSNIA AND HERZEGOVINA

    OpenAIRE

    Dedeić-Ljubović, AmeLa; Hukić, Mirsada; Bekić, DaRia; Zvizdić, AmrA

    2009-01-01

    Diarrhoeal disease is a major cause of illness and death among infants and young children worldwide. Among the Escherichia coli (E. coli) causing intestinal diseases, there are six well-described categories: enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enteroinvasive E. coli (EIEC), entero-pathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC) and enterotoxigenic E. coli (ETEC).

  1. Distribution of Diverse Escherichia coli between Cattle and Pasture

    OpenAIRE

    NandaKafle, Gitanjali; Seale, Tarren; Flint, Toby; Nepal, Madhav; Venter, Stephanus N.; Brözel, Volker S.

    2017-01-01

    Escherichia coli is widely considered to not survive for extended periods outside the intestines of warm-blooded animals; however, recent studies demonstrated that E. coli strains maintain populations in soil and water without any known fecal contamination. The objective of this study was to investigate whether the niche partitioning of E. coli occurs between cattle and their pasture. We attempted to clarify whether E. coli from bovine feces differs phenotypically and genotypically from isola...

  2. Lipocalin 2 is protective against E. coli pneumonia

    DEFF Research Database (Denmark)

    Wu, Hong; Santoni-Rugiu, Eric; Ralfkiaer, Elisabeth

    2010-01-01

    Lipocalin 2 is a bacteriostatic protein that binds the siderophore enterobactin, an iron-chelating molecule produced by Escherichia coli (E. coli) that is required for bacterial growth. Infection of the lungs by E. coli is rare despite a frequent exposure to this commensal bacterium. Lipocalin 2...... is an effector molecule of the innate immune system and could therefore play a role in hindering growth of E. coli in the lungs....

  3. Use of non-saccharomyces Torulaspora delbrueckii yeast strains in winemaking and brewing

    Directory of Open Access Journals (Sweden)

    Tataridis Panagiotis

    2013-01-01

    Full Text Available Selected Saccharomyces yeast strains have been used for more than 150 years in brewing and for several decades in winemaking. They are necessary in brewing because of the boiling of the wort, which results in the death of all yeast cells, with the exception of some Belgian style beers (ex. Lambic, where the wort is left to be colonized by indigenous yeast and bacteria from the environment and ferment naturally. In winemaking their use is also pertinent because they provide regular and timely fermentations, inhibit the growth of indigenous spoilage microorganisms and contribute to the desired sensory characters. Even though the use of selected Saccharomyces strains provides better quality assurance in winemaking in comparison to the unknown microbial consortia in the must, it has been debated for a long time now whether the use of selected industrial Saccharomyces strains results in wines with less sensory complexity and “terroir” character. In previous decades, non-Saccharomyces yeasts were mainly considered as spoilage/problematic yeast, since they exhibited low fermentation ability and other negative traits. In the last decades experiments have shown that there are some non-Saccharomyces strains (Candida, Pichia, Kluyveromyces, Torulaspora, etc which, even though they are not able to complete the fermentation they can still be used in sequential inoculation-fermentation with Saccharomyces to increase sensory complexity of the wines. Through fermentation in a laboratory scale, we have observed that the overall effects of selected Torulaspora delbrueckii yeast strains, is highly positive, leading to products with pronounced sensory complexity and floral/fruity aroma in winemaking and brewing.

  4. WGS accurately predicts antimicrobial resistance in Escherichia coli

    Science.gov (United States)

    Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...

  5. Increased multi-drug resistant Escherichia coli from hospitals in ...

    African Journals Online (AJOL)

    Background: Multidrug-resistant Escherichia coli (MDR E. coli) has become a major public health concern in Sudan and many countries, causing failure in treatment with consequent huge health burden. Objectives: To determine the prevalence and susceptibility of MDR E. coli isolated from patients in hospitals at Khartoum ...

  6. Antimicrobial susceptibility patterns of E. coli from clinical sources in ...

    African Journals Online (AJOL)

    Background: Escherichia coli is the leading cause of urinary tract, ear, wound and other infections in humans. Increasing rates of antimicrobial resistance among E. coli is a growing concern worldwide. Objectives: The aim of this study was to determine the prevalence and antimicrobial susceptibility of E. coli from clinical ...

  7. 77 FR 9888 - Shiga Toxin-Producing Escherichia coli

    Science.gov (United States)

    2012-02-21

    ... Toxin-Producing Escherichia coli in Certain Raw Beef Products AGENCY: Food Safety and Inspection Service... toxin-producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145). This new date..., that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26, O45, O103, O111, O121...

  8. Gene encoding virulence markers among Escherichia coli isolates ...

    African Journals Online (AJOL)

    River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was ...

  9. Isolation and genomic characterization of Escherichia coli O157:NM ...

    African Journals Online (AJOL)

    Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

  10. Neonatal infections caused by Escherichia coli at the National ...

    African Journals Online (AJOL)

    Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...

  11. neonatal infections caused by escherichia coli at the national

    African Journals Online (AJOL)

    boaz

    Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...

  12. Sequential fermentation using non-Saccharomyces yeasts for the reduction of alcohol content in wine

    Directory of Open Access Journals (Sweden)

    Ciani Maurizio

    2014-01-01

    Full Text Available Over the last few decades there has been a progressive increase in wine ethanol content due to global climate change and modified wine styles that involved viticulture and oenology practices. Among the different approaches and strategies to reduce alcohol content in wine we propose a sequential fermentation using immobilized non-Saccharomyces wine yeasts. Preliminary results showed that sequential fermentations with Hanseniaspora osmophila, Hanseniaspora uvarum, Metschnikowia pulcherrima, Starmerella bombicola and Saccharomyces cerevisiae strains showed an ethanol reduction when compared with pure S. cerevisiae fermentation trials.

  13. Incorporating Protein Biosynthesis into the Saccharomyces cerevisiae Genome-scale Metabolic Model

    DEFF Research Database (Denmark)

    Olivares Hernandez, Roberto

    Based on stoichiometric biochemical equations that occur into the cell, the genome-scale metabolic models can quantify the metabolic fluxes, which are regarded as the final representation of the physiological state of the cell. For Saccharomyces Cerevisiae the genome scale model has been construc......Based on stoichiometric biochemical equations that occur into the cell, the genome-scale metabolic models can quantify the metabolic fluxes, which are regarded as the final representation of the physiological state of the cell. For Saccharomyces Cerevisiae the genome scale model has been...

  14. The efficiency of functional mitochondrial replacement in Saccharomyces species has directional character

    DEFF Research Database (Denmark)

    Sulo, P.; Spirek, M.; Soltesova, A.

    2003-01-01

    into mutants devoid of mitochondrial DNA (rho(0)). Recently we have reported that the mitochondria transferred from Saccharomyces paradoxus restored partially the respiration in Saccharomyces cerevisiae rho(0) mutants. Here we present evidence that the S. cerevisiae mitochondria completely salvage from...... respiration deficiency, not only in conspecific isolates but also in S. paradoxus. The respiratory capacity in less-related species can be recovered exclusively in the presence of S. cerevisiae chromosomes. The efficiency of the re-established oxidative phosphorylation did not rely on the presence of introns...

  15. Ethanol production using engineered mutant E. coli

    Science.gov (United States)

    Ingram, Lonnie O.; Clark, David P.

    1991-01-01

    The subject invention concerns novel means and materials for producing ethanol as a fermentation product. Mutant E. coli are transformed with a gene coding for pyruvate decarboxylase activity. The resulting system is capable of producing relatively large amounts of ethanol from a variety of biomass sources.

  16. E. Coli: Preventing Outbreaks at Camp.

    Science.gov (United States)

    McKinney, Mary D.

    1996-01-01

    One strain of E. coli is not usually found in foods, but has been related to consumption of undercooked ground beef. Symptoms are stomach cramps and diarrhea, and 2-7% of infections lead to hemolytic uremic syndrome, which is life threatening. Camps can prevent outbreaks by avoiding uncooked meat on overnight campouts and requiring appropriate…

  17. Identifying New Small Proteins in Escherichia coli.

    Science.gov (United States)

    VanOrsdel, Caitlin E; Kelly, John P; Burke, Brittany N; Lein, Christina D; Oufiero, Christopher E; Sanchez, Joseph F; Wimmers, Larry E; Hearn, David J; Abuikhdair, Fatimeh J; Barnhart, Kathryn R; Duley, Michelle L; Ernst, Sarah E G; Kenerson, Briana A; Serafin, Aubrey J; Hemm, Matthew R

    2018-04-12

    The number of small proteins (SPs) encoded in the Escherichia coli genome is unknown, as current bioinformatics and biochemical techniques make short gene and small protein identification challenging. One method of small protein identification involves adding an epitope tag to the 3' end of a short open reading frame (sORF) on the chromosome, with synthesis confirmed by immunoblot assays. In this study, this strategy was used to identify new E. coli small proteins, tagging 80 sORFs in the E. coli genome, and assayed for protein synthesis. The selected sORFs represent diverse sequence characteristics, including degrees of sORF conservation, predicted transmembrane domains, sORF direction with respect to flanking genes, ribosome binding site (RBS) prediction, and ribosome profiling results. Of 80 sORFs, 36 resulted in encoded synthesized proteins-a 45% success rate. Modeling of detected versus non-detected small proteins analysis showed predictions based on RBS prediction, transcription data, and ribosome profiling had statistically-significant correlation with protein synthesis; however, there was no correlation between current sORF annotation and protein synthesis. These results suggest substantial numbers of small proteins remain undiscovered in E. coli, and existing bioinformatics techniques must continue to improve to facilitate identification. © 2018 The Authors. Proteomics Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Towson University.

  18. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  19. Optimization of plasmid electrotransformation into Escherichia coli ...

    African Journals Online (AJOL)

    In order to improve electroporation, optical density of bacteria, recovery time and electrical parameter (field strength and capacitance) were optimized using the Taguchi statistical method. ANOVA of obtained data indicated that the optimal conditions of electrotransformation of pET-28a (+) plasmid into Escherichia coli ...

  20. Transport proteins promoting Escherichia coli pathogenesis

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H.

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. PMID:24747185

  1. Transport proteins promoting Escherichia coli pathogenesis.

    Science.gov (United States)

    Tang, Fengyi; Saier, Milton H

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Isolation and molecular characterization of Campylobacter coli

    African Journals Online (AJOL)

    Campylobacter coli is prevalent among trade pigs in Kafanchan, Nigeria and is distributed across four of the five states from which trade pigs were sourced. Adequate hand hygiene is recommended for farmers, traders and Veterinary professionals handling pigs to prevent the transmission of this zoonosis to humans.

  3. Inhibition of Escherichia Coli, Salmonella and Staphylococcus ...

    African Journals Online (AJOL)

    Escherichia coli O157:H7, Salmonella typhimurium and Staphylococcus. aureus are of great concern to the food industry, especially in foods stored under refrigerated conditions where, unlike most food-borne pathogens are able to multiply. This investigation was conducted to study the inhibitory effect of some spice ...

  4. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    Emerging antibiotic resistance due to extended spectrum β-lactamase (ESBL) production limited the use of β-lactam antibiotics against Escherichia coli and Klebsiella pneumoniae. This observational study was conducted at the Microbiology department of the Children's Hospital, Lahore Pakistan, from June, 2009 to ...

  5. Mutagenic DNA repair in Escherichia coli

    International Nuclear Information System (INIS)

    Bridges, B.A.; Sharif, Firdaus

    1986-01-01

    The authors report a study of the misincorporation step in excision proficient umuC Escherichia coli as revealed by delayed photoreversal and show that it parallels the loss of photoreversibility of mutations induced in isogenic umu + bacteria; in both cases the end-point was mutation to streptomycin resistance. (author)

  6. Emergence of Quinolone Resistance amongst Escherichia coli ...

    African Journals Online (AJOL)

    Rate of resistance was 22.3% showing an increase in quinolone resistance when ... FQR E. coli was more common in patients with urinary tract infection (22.9%). ... in the faeces of healthy adults was 22.9%, 6.7% in children and 22.2% in avian. ... thereby aiding the spread of antibiotic resistant strains from avians to human ...

  7. Antibiotic resistance properties of uropathogenic Escherichia coli ...

    African Journals Online (AJOL)

    Purpose: To investigate the antibiotic resistance pattern of uropathogenic Escherichia coli (UPEC) strains isolated from pregnant women with history of recurrent urinary tract infections (RUTIs) and healthy pregnant women. Methods: A total of 485 high vaginal swab specimens were collected from pregnant women with ...

  8. Prevalence of Arcobacter, Escherichia coli, Staphylococcus aureus ...

    African Journals Online (AJOL)

    In this study, varying level of resistance of Escherichia coli 66(84.6%), Salmonella 6(100%) and Arcobacter 57(100%) to amoxicillin was observed. The susceptibility pattern indicates that the bacterial isolates exhibited a varying level of resistance to two or more antimicrobial agents with maximum resistance to amoxicillin.

  9. E.coli O157:H7

    Directory of Open Access Journals (Sweden)

    Treor Francis Fernandez

    2008-06-01

    Full Text Available The serious nature of the symptoms of haemorrhagic colitis and HUS and the apparent low infectious dose (<100 cells of E.coli O157:H7 places this food borne pathogen a most serious of known food borne pathogens. Persuasive evidence suggests that healthy cattle are a reservoir of O157 and they can enter the food chain to provide a source of exposure for humans. A possible route of transmission of O157 VTEC may involve infections initially in calves that shed their organism into faecal slurry that may be used on grazing grass. This provides potential for infection of other animals from which the organism may contaminate milk or carcasses at slaughter. Possible sources of VTEC in healthy animals other E.coli O157:H7 than cattle and a wider range of foodstuffs require further investigation. Many features of E.coli O157:H7 strains remain poorly understood. It includes: (i Role of virulent genes in the animal, (ii Mechanism of evolution of the organism, (iii The progress of individual cases of E.coli O157:H7 infection, and (iv The difference in incidence of infection in different geographical areas. [Veterinary World 2008; 1(3.000: 83-87

  10. Leaner and meaner genomes in Escherichia coli

    DEFF Research Database (Denmark)

    Ussery, David

    2006-01-01

    A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions....

  11. ANTIMICIROBIAL SUSCEPTIBILITY PATTERNS OF Escherichia coli ...

    African Journals Online (AJOL)

    DR. AMINU

    A total of 56 and 24 strains of E. coli and Shigella sp. isolated from children less than five years with diarrhoea attending 3 ... parasitic infections, as well as food intolerance, reaction to ..... Escherichia coil 0157:H7 as a model of entry of a new.

  12. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    ; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  13. Exploring the Saccharomyces cerevisiae Volatile Metabolome: Indigenous versus Commercial Strains

    Science.gov (United States)

    Alves, Zélia; Melo, André; Figueiredo, Ana Raquel; Coimbra, Manuel A.; Gomes, Ana C.; Rocha, Sílvia M.

    2015-01-01

    Winemaking is a highly industrialized process and a number of commercial Saccharomyces cerevisiae strains are used around the world, neglecting the diversity of native yeast strains that are responsible for the production of wines peculiar flavours. The aim of this study was to in-depth establish the S. cerevisiae volatile metabolome and to assess inter-strains variability. To fulfill this objective, two indigenous strains (BT2652 and BT2453 isolated from spontaneous fermentation of grapes collected in Bairrada Appellation, Portugal) and two commercial strains (CSc1 and CSc2) S. cerevisiae were analysed using a methodology based on advanced multidimensional gas chromatography (HS-SPME/GC×GC-ToFMS) tandem with multivariate analysis. A total of 257 volatile metabolites were identified, distributed over the chemical families of acetals, acids, alcohols, aldehydes, ketones, terpenic compounds, esters, ethers, furan-type compounds, hydrocarbons, pyrans, pyrazines and S-compounds. Some of these families are related with metabolic pathways of amino acid, carbohydrate and fatty acid metabolism as well as mono and sesquiterpenic biosynthesis. Principal Component Analysis (PCA) was used with a dataset comprising all variables (257 volatile components), and a distinction was observed between commercial and indigenous strains, which suggests inter-strains variability. In a second step, a subset containing esters and terpenic compounds (C10 and C15), metabolites of particular relevance to wine aroma, was also analysed using PCA. The terpenic and ester profiles express the strains variability and their potential contribution to the wine aromas, specially the BT2453, which produced the higher terpenic content. This research contributes to understand the metabolic diversity of indigenous wine microflora versus commercial strains and achieved knowledge that may be further exploited to produce wines with peculiar aroma properties. PMID:26600152

  14. Effects of ultraviolet radiation on saccharomyces uvarum metabolism

    International Nuclear Information System (INIS)

    Luciano, J.Z.; Hix, C.

    1987-01-01

    The objective of this study was to measure the effect of UV radiation on the metabolism of Saccharomcyes uvarum in wort used in beer production. Pure yeast cultures were exposed to a Westinghouse G8T5 germicidal lamp for 10, 20, 30 and 40 minutes and added to fresh wort. The cultures were allowed to ferment for 96 hours at 130 C and fermentation products were assayed at 24 hour intervals and analyzed on a SCABA BEER ANALYZER. Metabolic parameters measured were balling, alcohol and cell count. Percent alcohol (V/V %) increased significantly at all exposures, but as the UV dosage increased, alcohol levels showed a significant decline with longer exposures. The assimilation of sugars or balling levels dropped at each exposure level among samples. The ability for the yeast to assimilate sugars decreased as UV exposure was increased although pitching rates fluctuated. (Pitching rates are the cell count readings at inoculation). None of the samples showed a logarithmic growth pattern, except for the controls which did not exhibit a lag phase. All other samples decreased cell counts as exposure levels increased, without peaks. Substrate availability was not a factor in the metabolism of Saccharomyces uvarum. Cell count levels at each exposure could have possibly affected the metabolic parameters because of excessive cell killing. Viabilities at the exposure levels studied show that the number of live cells available for nutrient uptake was lower at each level. However, the peak levels of the parameters measured were very close to the controls. Although the availability of cells was low, metabolic rates could have been altered by the UV light

  15. Phenotypic and metabolic traits of commercial Saccharomyces cerevisiae yeasts.

    Science.gov (United States)

    Barbosa, Catarina; Lage, Patrícia; Vilela, Alice; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

    2014-01-01

    Currently, pursuing yeast strains that display both a high potential fitness for alcoholic fermentation and a favorable impact on quality is a major goal in the alcoholic beverage industry. This considerable industrial interest has led to many studies characterizing the phenotypic and metabolic traits of commercial yeast populations. In this study, 20 Saccharomyces cerevisiae strains from different geographical origins exhibited high phenotypic diversity when their response to nine biotechnologically relevant conditions was examined. Next, the fermentation fitness and metabolic traits of eight selected strains with a unique phenotypic profile were evaluated in a high-sugar synthetic medium under two nitrogen regimes. Although the strains exhibited significant differences in nitrogen requirements and utilization rates, a direct relationship between nitrogen consumption, specific growth rate, cell biomass, cell viability, acetic acid and glycerol formation was only observed under high-nitrogen conditions. In contrast, the strains produced more succinic acid under the low-nitrogen regime, and a direct relationship with the final cell biomass was established. Glucose and fructose utilization patterns depended on both yeast strain and nitrogen availability. For low-nitrogen fermentation, three strains did not fully degrade the fructose. This study validates phenotypic and metabolic diversity among commercial wine yeasts and contributes new findings on the relationship between nitrogen availability, yeast cell growth and sugar utilization. We suggest that measuring nitrogen during the stationary growth phase is important because yeast cells fermentative activity is not exclusively related to population size, as previously assumed, but it is also related to the quantity of nitrogen consumed during this growth phase.

  16. The effect of acetaminophen on ubiquitin homeostasis in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Angelina Huseinovic

    Full Text Available Acetaminophen (APAP, although considered a safe drug, is one of the major causes of acute liver failure by overdose, and therapeutic chronic use can cause serious health problems. Although the reactive APAP metabolite N-acetyl-p-benzoquinoneimine (NAPQI is clearly linked to liver toxicity, toxicity of APAP is also found without drug metabolism of APAP to NAPQI. To get more insight into mechanisms of APAP toxicity, a genome-wide screen in Saccharomyces cerevisiae for APAP-resistant deletion strains was performed. In this screen we identified genes related to the DNA damage response. Next, we investigated the link between genotype and APAP-induced toxicity or resistance by performing a more detailed screen with a library containing mutants of 1522 genes related to nuclear processes, like DNA repair and chromatin remodelling. We identified 233 strains that had an altered growth rate relative to wild type, of which 107 showed increased resistance to APAP and 126 showed increased sensitivity. Gene Ontology analysis identified ubiquitin homeostasis, regulation of transcription of RNA polymerase II genes, and the mitochondria-to-nucleus signalling pathway to be associated with APAP resistance, while histone exchange and modification, and vesicular transport were connected to APAP sensitivity. Indeed, we observed a link between ubiquitin levels and APAP resistance, whereby ubiquitin deficiency conferred resistance to APAP toxicity while ubiquitin overexpression resulted in sensitivity. The toxicity profile of various chemicals, APAP, and its positional isomer AMAP on a series of deletion strains with ubiquitin deficiency showed a unique resistance pattern for APAP. Furthermore, exposure to APAP increased the level of free ubiquitin and influenced the ubiquitination of proteins. Together, these results uncover a role for ubiquitin homeostasis in APAP-induced toxicity.

  17. Saccharomyces cerevisiae as a model organism: a comparative study.

    Directory of Open Access Journals (Sweden)

    Hiren Karathia

    Full Text Available BACKGROUND: Model organisms are used for research because they provide a framework on which to develop and optimize methods that facilitate and standardize analysis. Such organisms should be representative of the living beings for which they are to serve as proxy. However, in practice, a model organism is often selected ad hoc, and without considering its representativeness, because a systematic and rational method to include this consideration in the selection process is still lacking. METHODOLOGY/PRINCIPAL FINDINGS: In this work we propose such a method and apply it in a pilot study of strengths and limitations of Saccharomyces cerevisiae as a model organism. The method relies on the functional classification of proteins into different biological pathways and processes and on full proteome comparisons between the putative model organism and other organisms for which we would like to extrapolate results. Here we compare S. cerevisiae to 704 other organisms from various phyla. For each organism, our results identify the pathways and processes for which S. cerevisiae is predicted to be a good model to extrapolate from. We find that animals in general and Homo sapiens in particular are some of the non-fungal organisms for which S. cerevisiae is likely to be a good model in which to study a significant fraction of common biological processes. We validate our approach by correctly predicting which organisms are phenotypically more distant from S. cerevisiae with respect to several different biological processes. CONCLUSIONS/SIGNIFICANCE: The method we propose could be used to choose appropriate substitute model organisms for the study of biological processes in other species that are harder to study. For example, one could identify appropriate models to study either pathologies in humans or specific biological processes in species with a long development time, such as plants.

  18. Metabolism and Regulation of Glycerolipids in the Yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Henry, Susan A.; Kohlwein, Sepp D.; Carman, George M.

    2012-01-01

    Due to its genetic tractability and increasing wealth of accessible data, the yeast Saccharomyces cerevisiae is a model system of choice for the study of the genetics, biochemistry, and cell biology of eukaryotic lipid metabolism. Glycerolipids (e.g., phospholipids and triacylglycerol) and their precursors are synthesized and metabolized by enzymes associated with the cytosol and membranous organelles, including endoplasmic reticulum, mitochondria, and lipid droplets. Genetic and biochemical analyses have revealed that glycerolipids play important roles in cell signaling, membrane trafficking, and anchoring of membrane proteins in addition to membrane structure. The expression of glycerolipid enzymes is controlled by a variety of conditions including growth stage and nutrient availability. Much of this regulation occurs at the transcriptional level and involves the Ino2–Ino4 activation complex and the Opi1 repressor, which interacts with Ino2 to attenuate transcriptional activation of UASINO-containing glycerolipid biosynthetic genes. Cellular levels of phosphatidic acid, precursor to all membrane phospholipids and the storage lipid triacylglycerol, regulates transcription of UASINO-containing genes by tethering Opi1 to the nuclear/endoplasmic reticulum membrane and controlling its translocation into the nucleus, a mechanism largely controlled by inositol availability. The transcriptional activator Zap1 controls the expression of some phospholipid synthesis genes in response to zinc availability. Regulatory mechanisms also include control of catalytic activity of glycerolipid enzymes by water-soluble precursors, products and lipids, and covalent modification of phosphorylation, while in vivo function of some enzymes is governed by their subcellular location. Genome-wide genetic analysis indicates coordinate regulation between glycerolipid metabolism and a broad spectrum of metabolic pathways. PMID:22345606

  19. Overproduction of Geranylgeraniol by Metabolically Engineered Saccharomyces cerevisiae▿

    Science.gov (United States)

    Tokuhiro, Kenro; Muramatsu, Masayoshi; Ohto, Chikara; Kawaguchi, Toshiya; Obata, Shusei; Muramoto, Nobuhiko; Hirai, Masana; Takahashi, Haruo; Kondo, Akihiko; Sakuradani, Eiji; Shimizu, Sakayu

    2009-01-01

    (E, E, E)-Geranylgeraniol (GGOH) is a valuable starting material for perfumes and pharmaceutical products. In the yeast Saccharomyces cerevisiae, GGOH is synthesized from the end products of the mevalonate pathway through the sequential reactions of farnesyl diphosphate synthetase (encoded by the ERG20 gene), geranylgeranyl diphosphate synthase (the BTS1 gene), and some endogenous phosphatases. We demonstrated that overexpression of the diacylglycerol diphosphate phosphatase (DPP1) gene could promote GGOH production. We also found that overexpression of a BTS1-DPP1 fusion gene was more efficient for producing GGOH than coexpression of these genes separately. Overexpression of the hydroxymethylglutaryl-coenzyme A reductase (HMG1) gene, which encodes the major rate-limiting enzyme of the mevalonate pathway, resulted in overproduction of squalene (191.9 mg liter−1) rather than GGOH (0.2 mg liter−1) in test tube cultures. Coexpression of the BTS1-DPP1 fusion gene along with the HMG1 gene partially redirected the metabolic flux from squalene to GGOH. Additional expression of a BTS1-ERG20 fusion gene resulted in an almost complete shift of the flux to GGOH production (228.8 mg liter−1 GGOH and 6.5 mg liter−1 squalene). Finally, we constructed a diploid prototrophic strain coexpressing the HMG1, BTS1-DPP1, and BTS1-ERG20 genes from multicopy integration vectors. This strain attained 3.31 g liter−1 GGOH production in a 10-liter jar fermentor with gradual feeding of a mixed glucose and ethanol solution. The use of bifunctional fusion genes such as the BTS1-DPP1 and ERG20-BTS1 genes that code sequential enzymes in the metabolic pathway was an effective method for metabolic engineering. PMID:19592534

  20. High level secretion of cellobiohydrolases by Saccharomyces cerevisiae

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    Ahlgren Simon

    2011-09-01

    Full Text Available Abstract Background The main technological impediment to widespread utilization of lignocellulose for the production of fuels and chemicals is the lack of low-cost technologies to overcome its recalcitrance. Organisms that hydrolyze lignocellulose and produce a valuable product such as ethanol at a high rate and titer could significantly reduce the costs of biomass conversion technologies, and will allow separate conversion steps to be combined in a consolidated bioprocess (CBP. Development of Saccharomyces cerevisiae for CBP requires the high level secretion of cellulases, particularly cellobiohydrolases. Results We expressed various cellobiohydrolases to identify enzymes that were efficiently secreted by S. cerevisiae. For enhanced cellulose hydrolysis, we engineered bimodular derivatives of a well secreted enzyme that naturally lacks the carbohydrate-binding module, and constructed strains expressing combinations of cbh1 and cbh2 genes. Though there was significant variability in the enzyme levels produced, up to approximately 0.3 g/L CBH1 and approximately 1 g/L CBH2 could be produced in high cell density fermentations. Furthermore, we could show activation of the unfolded protein response as a result of cellobiohydrolase production. Finally, we report fermentation of microcrystalline cellulose (Avicel™ to ethanol by CBH-producing S. cerevisiae strains with the addition of beta-glucosidase. Conclusions Gene or protein specific features and compatibility with the host are important for efficient cellobiohydrolase secretion in yeast. The present work demonstrated that production of both CBH1 and CBH2 could be improved to levels where the barrier to CBH sufficiency in the hydrolysis of cellulose was overcome.

  1. Molecular Mechanism of Terbinafine Resistance in Saccharomyces cerevisiae

    Science.gov (United States)

    Leber, Regina; Fuchsbichler, Sandra; Klobučníková, Vlasta; Schweighofer, Natascha; Pitters, Eva; Wohlfarter, Kathrin; Lederer, Mojca; Landl, Karina; Ruckenstuhl, Christoph; Hapala, Ivan; Turnowsky, Friederike

    2003-01-01

    Ten mutants of the yeast Saccharomyces cerevisiae resistant to the antimycotic terbinafine were isolated after chemical or UV mutagenesis. Molecular analysis of these mutants revealed single base pair exchanges in the ERG1 gene coding for squalene epoxidase, the target of terbinafine. The mutants did not show cross-resistance to any of the substrates of various pleiotropic drug resistance efflux pumps tested. The ERG1 mRNA levels in the mutants did not differ from those in the wild-type parent strains. Terbinafine resistance was transmitted with the mutated alleles in gene replacement experiments, proving that single amino acid substitutions in the Erg1 protein were sufficient to confer the resistance phenotype. The amino acid changes caused by the point mutations were clustered in two regions of the Erg1 protein. Seven mutants carried the amino acid substitutions F402L (one mutant), F420L (one mutant), and P430S (five mutants) in the C-terminal part of the protein; and three mutants carried an L251F exchange in the central part of the protein. Interestingly, all exchanges identified involved amino acids which are conserved in the squalene epoxidases of yeasts and mammals. Two mutations that were generated by PCR mutagenesis of the ERG1 gene and that conferred terbinafine resistance mapped in the same regions of the Erg1 protein, with one resulting in an L251F exchange and the other resulting in an F433S exchange. The results strongly indicate that these regions are responsible for the interaction of yeast squalene epoxidase with terbinafine. PMID:14638499

  2. Ecological and Genetic Barriers Differentiate Natural Populations of Saccharomyces cerevisiae.

    Science.gov (United States)

    Clowers, Katie J; Heilberger, Justin; Piotrowski, Jeff S; Will, Jessica L; Gasch, Audrey P

    2015-09-01

    How populations that inhabit the same geographical area become genetically differentiated is not clear. To investigate this, we characterized phenotypic and genetic differences between two populations of Saccharomyces cerevisiae that in some cases inhabit the same environment but show relatively little gene flow. We profiled stress sensitivity in a group of vineyard isolates and a group of oak-soil strains and found several niche-related phenotypes that distinguish the populations. We performed bulk-segregant mapping on two of the distinguishing traits: The vineyard-specific ability to grow in grape juice and oak-specific tolerance to the cell wall damaging drug Congo red. To implicate causal genes, we also performed a chemical genomic screen in the lab-strain deletion collection and identified many important genes that fell under quantitative trait loci peaks. One gene important for growth in grape juice and identified by both the mapping and the screen was SSU1, a sulfite-nitrite pump implicated in wine fermentations. The beneficial allele is generated by a known translocation that we reasoned may also serve as a genetic barrier. We found that the translocation is prevalent in vineyard strains, but absent in oak strains, and presents a postzygotic barrier to spore viability. Furthermore, the translocation was associated with a fitness cost to the rapid growth rate seen in oak-soil strains. Our results reveal the translocation as a dual-function locus that enforces ecological differentiation while producing a genetic barrier to gene flow in these sympatric populations. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  3. Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae.

    Science.gov (United States)

    Jongedijk, Esmer; Cankar, Katarina; Ranzijn, Jorn; van der Krol, Sander; Bouwmeester, Harro; Beekwilder, Jules

    2015-01-01

    Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (-)-limonene synthase from Perilla frutescens and a (+)-limonene synthase from Citrus limon. Both proteins were expressed either with their native plastid targeting signal or in a truncated form in which the plastidial sorting signal was removed. The yeast host strain for expression was AE9 K197G, which expresses a mutant Erg20 enzyme. This enzyme catalyses the formation of geranyl diphosphate, which is the precursor for monoterpenes. Several methods were tested to capture limonene produced by the yeast. Extraction from the culture medium by pentane, or by the addition of CaCl2 followed by solid-phase micro-extraction, did not lead to detectable limonene, indicating that limonene is rapidly lost from the culture medium. Volatile terpenes such as limonene may also be trapped in a dodecane phase added to the medium during fermentation. This method resulted in recovery of 0.028 mg/l (+)-limonene and 0.060 mg/l (-)-limonene in strains using the truncated Citrus and Perilla synthases, respectively. Trapping the headspace during culture of the limonene synthase-expressing strains resulted in higher titres, at 0.12 mg/l (+)-limonene and 0.49 mg/l (-)-limonene. These results show that the volatile properties of the olefins produced require specific methods for efficient recovery of these molecules from biotechnological production systems. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Efficacy and safety of Saccharomyces boulardii for acute diarrhea.

    Science.gov (United States)

    Feizizadeh, Sahar; Salehi-Abargouei, Amin; Akbari, Vajihe

    2014-07-01

    The efficacy of Saccharomyces boulardii for treatment of childhood diarrhea remains unclear. Our objective was to systematically review data on the effect of S. boulardii on acute childhood diarrhea. Our data sources included Medline, Embase, CINAHL, Scopus, and The Cochrane Library up to September 2013 without language restrictions. Randomized controlled trials and non-randomized trials that evaluated effectiveness of S. boulardii for treatment of acute diarrhea in children were included. Two reviewers independently evaluated studies for eligibility and quality and extracted the data. In total, 1248 articles were identified, of which 22 met the inclusion criteria. Pooling data from trials showed that S. boulardii significantly reduced the duration of diarrhea (mean difference [MD], -19.7 hours; 95% confidence interval [CI], -26.05 to -13.34), stool frequency on day 2 (MD, -0.74; 95% CI, -1.38 to -0.10) and day 3 (MD, -1.24; 95% CI, -2.13 to -0.35), the risk for diarrhea on day 3 (risk ratio [RR], 0.41; 95% CI, 0.27 to 0.60) and day 4 (RR, 0.38; 95% CI, 0.24 to 0.59) after intervention compared with control. The studies included in this review were varied in the definition of diarrhea, the termination of diarrhea, inclusion and exclusion criteria, and their methodological quality. This review and meta-analysis show that S. boulardii is safe and has clear beneficial effects in children who have acute diarrhea. However, additional studies using head-to-head comparisons are needed to define the best dosage of S. boulardii for diarrhea with different causes. Copyright © 2014 by the American Academy of Pediatrics.

  5. Effectiveness and safety of Saccharomyces boulardii for acute infectious diarrhea.

    Science.gov (United States)

    Dinleyici, Ener Cagri; Eren, Makbule; Ozen, Metehan; Yargic, Zeynel Abidin; Vandenplas, Yvan

    2012-04-01

    Acute diarrhea continues to be a leading cause of morbidity, hospitalization and mortality worldwide and probiotics have been proposed as a complementary therapy in the treatment of acute diarrhea. Regarding the treatment of acute diarrhea, a few probiotics including Saccharomyces boulardii seem to be promising therapeutic agents. We performed a systematic review and meta-analysis regarding the use of S. boulardii in the treatment of acute infectious diarrhea with relevant studies that searched with the PubMed, Embase, Scopus, Google Scholar, the Cochrane Controlled Trials Library, and the Cochrane Database of Systematic Reviews through October 2011. This review describes the effects of S. boulardii on the duration of diarrhea, the risk of diarrhea during the treatment (especially at the third day) and duration of hospitalization in patients with acute infectious diarrhea. This review also focused on the potential effects of S. boulardii for acute infectious diarrhea due to different etiological causes. S. boulardii significantly reduced the duration of diarrhea approximately 24 h and that of hospitalization approximately 20 h. S. boulardii shortened the initial phase of watery stools; mean number of stools started to decrease at day 2; moreover, a significant reduction was reported at days 3 and 4. This systematic review and meta-analysis of the efficacy of S. boulardii in the treatment of acute infectious diarrhea show that there is strong evidence that this probiotic has a clinically significant benefit, whatever the cause, including in developing countries. Therefore, with S. boulardii, the shortened duration of diarrhea and the reduction in hospital stay result in social and economic benefits.

  6. Saccharomyces boulardii does not prevent relapse of Crohn's disease.

    Science.gov (United States)

    Bourreille, Arnaud; Cadiot, Guillaume; Le Dreau, Gérard; Laharie, David; Beaugerie, Laurent; Dupas, Jean-Louis; Marteau, Philippe; Rampal, Patrick; Moyse, Dominique; Saleh, Ashraf; Le Guern, Marie-Emmanuelle; Galmiche, Jean-Paul

    2013-08-01

    Saccharomyces boulardii is a probiotic yeast that has been shown to have beneficial effects on the intestinal epithelial barrier and digestive immune system. There is preliminary evidence that S boulardii could be used to treat patients with Crohn's disease (CD). We performed a randomized, placebo-controlled trial to evaluate the effects of S boulardii in patients with CD who underwent remission during therapy with steroids or aminosalicylates. We performed a prospective study of 165 patients who achieved remission after treatment with steroids or salicylates; they were randomly assigned to groups given S boulardii (1 g/day) or placebo for 52 weeks. The primary end point was the percentage of patients in remission at week 52. Time to relapse, Crohn's disease activity index scores, and changes in parameters of inflammation were secondary end points. CD relapsed in 80 patients, 38 in the S boulardii group (47.5%) and 42 in the placebo group (53.2%, a nonsignificant difference). The median time to relapse did not differ significantly between patients given S boulardii (40.7 weeks) vs placebo (39.0 weeks). There were no significant differences between groups in mean Crohn's disease activity index scores or erythrocyte sedimentation rates or in median levels of C-reactive protein. In a post hoc analysis, nonsmokers given S boulardii were less likely to experience a relapse of CD than nonsmokers given placebo, but this finding requires confirmation. Although the probiotic yeast S boulardii is safe and well tolerated, it does not appear to have any beneficial effects for patients with CD in remission after steroid or salicylate therapies. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

  7. Genomic evolution of Saccharomyces cerevisiae under Chinese rice wine fermentation.

    Science.gov (United States)

    Li, Yudong; Zhang, Weiping; Zheng, Daoqiong; Zhou, Zhan; Yu, Wenwen; Zhang, Lei; Feng, Lifang; Liang, Xinle; Guan, Wenjun; Zhou, Jingwen; Chen, Jian; Lin, Zhenguo

    2014-09-10

    Rice wine fermentation represents a unique environment for the evolution of the budding yeast, Saccharomyces cerevisiae. To understand how the selection pressure shaped the yeast genome and gene regulation, we determined the genome sequence and transcriptome of a S. cerevisiae strain YHJ7 isolated from Chinese rice wine (Huangjiu), a popular traditional alcoholic beverage in China. By comparing the genome of YHJ7 to the lab strain S288c, a Japanese sake strain K7, and a Chinese industrial bioethanol strain YJSH1, we identified many genomic sequence and structural variations in YHJ7, which are mainly located in subtelomeric regions, suggesting that these regions play an important role in genomic evolution between strains. In addition, our comparative transcriptome analysis between YHJ7 and S288c revealed a set of differentially expressed genes, including those involved in glucose transport (e.g., HXT2, HXT7) and oxidoredutase activity (e.g., AAD10, ADH7). Interestingly, many of these genomic and transcriptional variations are directly or indirectly associated with the adaptation of YHJ7 strain to its specific niches. Our molecular evolution analysis suggested that Japanese sake strains (K7/UC5) were derived from Chinese rice wine strains (YHJ7) at least approximately 2,300 years ago, providing the first molecular evidence elucidating the origin of Japanese sake strains. Our results depict interesting insights regarding the evolution of yeast during rice wine fermentation, and provided a valuable resource for genetic engineering to improve industrial wine-making strains. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  8. Studies of anaerobic and aerobic glycolysis in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    den Hollander, J.A.; Ugurbil, K.; Brown, T.R.; Bednar, M.; Redfield, C.; Shulman, R.G.

    1986-01-01

    Glucose metabolism was followed in suspensions of Saccharomyces cerevisiae by using 13C NMR and 14C radioactive labeling techniques and by Warburg manometer experiments. These experiments were performed for cells grown with various carbon sources in the growth medium, so as to evaluate the effect of catabolite repression. The rate of glucose utilization was most conveniently determined by the 13C NMR experiments, which measured the concentration of [1-13C]glucose, whereas the distribution of end products was determined from the 13C and the 14C experiments. By combining these measurements the flows into the various pathways that contribute to glucose catabolism were estimated, and the effect of oxygen upon glucose catabolism was evaluated. From these measurements, the Pasteur quotient (PQ) for glucose catabolism was calculated to be 2.95 for acetate-grown cells and 1.89 for cells grown on glucose into saturation. The Warburg experiments provided an independent estimate of glucose catabolism. The PQ estimated from Warburg experiments was 2.9 for acetate-grown cells in excellent agreement with the labeled carbon experiments and 4.6 for cells grown into saturation, which did not agree. Possible explanations of these differences are discussed. From these data an estimate is obtained of the net flow through the Embden-Meyerhof-Parnas pathway. The backward flow through fructose-1,6-bisphosphatase (Fru-1,6-P2-ase) was calculated from the scrambling of the 13C label of [1-13C]glucose into the C1 and C6 positions of trehalose. Combining these data allowed us to calculate the net flux through phosphofructokinase (PFK). For acetate-grown cells we found that the relative flow through PFK is a factor of 1.7 faster anaerobically than aerobically

  9. Comparison of heterologous xylose transporters in recombinant Saccharomyces cerevisiae

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    Hahn-Hägerdal Bärbel

    2010-03-01

    Full Text Available Abstract Background Baker's yeast (Saccharomyces cerevisiae has been engineered for xylose utilization to enable production of fuel ethanol from lignocellulose raw material. One unresolved challenge is that S. cerevisiae lacks a dedicated transport system for pentose sugars, which means that xylose is transported by non-specific Hxt transporters with comparatively low transport rate and affinity for xylose. Results In this study, we compared three heterologous xylose transporters that have recently been shown to improve xylose uptake under different experimental conditions. The transporters Gxf1, Sut1 and At5g59250 from Candida intermedia, Pichia stipitis and Arabidopsis thaliana, respectively, were expressed in isogenic strains of S. cerevisiae and the transport kinetics and utilization of xylose was evaluated. Expression of the Gxf1 and Sut1 transporters led to significantly increased affinity and transport rates of xylose. In batch cultivation at 4 g/L xylose concentration, improved transport kinetics led to a corresponding increase in xylose utilization, whereas no correlation could be demonstrated at xylose concentrations greater than 15 g/L. The relative contribution of native sugar transporters to the overall xylose transport capacity was also estimated during growth on glucose and xylose. Conclusions Kinetic characterization and aerobic batch cultivation of strains expressing the Gxf1, Sut1 and At5g59250 transporters showed a direct relationship between transport kinetics and xylose growth. The Gxf1 transporter had the highest transport capacity and the highest xylose growth rate, followed by the Sut1 transporter. The range in which transport controlled the growth rate was determined to between 0 and 15 g/L xylose. The role of catabolite repression in regulation of native transporters was also confirmed by the observation that xylose transport by native S. cerevisiae transporters increased significantly during cultivation in xylose and

  10. Enhanced isoprenoid production from xylose by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Kwak, Suryang; Kim, Soo Rin; Xu, Haiqing; Zhang, Guo-Chang; Lane, Stephan; Kim, Heejin; Jin, Yong-Su

    2017-11-01

    Saccharomyces cerevisiae has limited capabilities for producing fuels and chemicals derived from acetyl-CoA, such as isoprenoids, due to a rigid flux partition toward ethanol during glucose metabolism. Despite numerous efforts, xylose fermentation by engineered yeast harboring heterologous xylose metabolic pathways was not as efficient as glucose fermentation for producing ethanol. Therefore, we hypothesized that xylose metabolism by engineered yeast might be a better fit for producing non-ethanol metabolites. We indeed found that engineered S. cerevisiae on xylose showed higher expression levels of the enzymes involved in ethanol assimilation and cytosolic acetyl-CoA synthesis than on glucose. When genetic perturbations necessary for overproducing squalene and amorphadiene were introduced into engineered S. cerevisiae capable of fermenting xylose, we observed higher titers and yields of isoprenoids under xylose than glucose conditions. Specifically, co-overexpression of a truncated HMG1 (tHMG1) and ERG10 led to substantially higher squalene accumulation under xylose than glucose conditions. In contrast to glucose utilization producing massive amounts of ethanol regardless of aeration, xylose utilization allowed much less amounts of ethanol accumulation, indicating ethanol is simultaneously re-assimilated with xylose consumption and utilized for the biosynthesis of cytosolic acetyl-CoA. In addition, xylose utilization by engineered yeast with overexpression of tHMG1, ERG10, and ADS coding for amorphadiene synthase, and the down-regulation of ERG9 resulted in enhanced amorphadiene production as compared to glucose utilization. These results suggest that the problem of the rigid flux partition toward ethanol production in yeast during the production of isoprenoids and other acetyl-CoA derived chemicals can be bypassed by using xylose instead of glucose as a carbon source. Biotechnol. Bioeng. 2017;114: 2581-2591. © 2017 Wiley Periodicals, Inc. © 2017 Wiley

  11. Immobilization of Saccharomyces Cerevisiae in Rice Hulls for Ethanol Production

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    Edita Martini

    2011-05-01

    Full Text Available The whole cell immobilization in ethanol fermentation can be done by using natural carriers or through synthetic carriers. All of these methods have the same purpose of retaining high cell concentrations within a certain defined region of space which leads to higher ethanol productivity. Lignocellulosic plant substance represents one of highly potential sources in ethanol production. Some studies have found that cellulosic substances substances can also be used as a natural carrier in cell immobilization by re-circulating pre-culture medium into a reactor. In this experiment, rice hulls without any treatment were used to immobilize Saccharomyces cerevisiae through semi solid state incubation combined with re-circulating pre-culture medium. The scanning electron microscopy (SEM pictures of the carrier show that the yeast cells are absorbed and embedded to the rice hull pore. In liquid batch fermentation system with an initial sugar concentration of 50 g/L, nearly 100% total sugar was consumed after 48 hours. This resulted in an ethanol yield of 0.32 g ethanol/g glucose, which is 62.7% of the theoretical value. Ethanol productivity of 0.59 g/(L.h is 2.3 fold higher than that of free cells which is 0.26 g/(L.h. An effort to reuse the immobilized cells in liquid fermentation system showed poor results due to cell desorption in the first batch which led to high sugar concentration inhibitory effect in the second batch fermentation. This might be solved by using semi solid fermentation process in the future work.

  12. Predicting functional upstream open reading frames in Saccharomyces cerevisiae

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    Kristiansson Erik

    2009-12-01

    Full Text Available Abstract Background Some upstream open reading frames (uORFs regulate gene expression (i.e., they are functional and can play key roles in keeping organisms healthy. However, how uORFs are involved in gene regulation is not yet fully understood. In order to get a complete view of how uORFs are involved in gene regulation, it is expected that a large number of experimentally verified functional uORFs are needed. Unfortunately, wet-experiments to verify that uORFs are functional are expensive. Results In this paper, a new computational approach to predicting functional uORFs in the yeast Saccharomyces cerevisiae is presented. Our approach is based on inductive logic programming and makes use of a novel combination of knowledge about biological conservation, Gene Ontology annotations and genes' responses to different conditions. Our method results in a set of simple and informative hypotheses with an estimated sensitivity of 76%. The hypotheses predict 301 further genes to have 398 novel functional uORFs. Three (RPC11, TPK1, and FOL1 of these 301 genes have been hypothesised, following wet-experiments, by a related study to have functional uORFs. A comparison with another related study suggests that eleven of the predicted functional uORFs from genes LDB17, HEM3, CIN8, BCK2, PMC1, FAS1, APP1, ACC1, CKA2, SUR1, and ATH1 are strong candidates for wet-lab experimental studies. Conclusions Learning based prediction of functional uORFs can be done with a high sensitivity. The predictions made in this study can serve as a list of candidates for subsequent wet-lab verification and might help to elucidate the regulatory roles of uORFs.

  13. Crystallization and preliminary X-ray analysis of a decameric form of cytosolic thioredoxin peroxidase 1 (Tsa1), C47S mutant, from Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcos Antonio de, E-mail: scaff@lnls.br; Genu, Victor; Discola, Karen Fulan; Alves, Simone Vidigal; Netto, Luis Eduardo Soares [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 05508-900 São Paulo-SP (Brazil); Guimarães, Beatriz Gomes, E-mail: scaff@lnls.br [Centro de Biologia Molecular Estrutural, Laboratório Nacional de Luz Síncrotron, 13084-971 Campinas-SP (Brazil); Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 05508-900 São Paulo-SP (Brazil)

    2007-08-01

    A recombinant mutant (C47S) of cytosolic thioredoxin peroxidase 1 from S. cerevisiae was expressed, purified and crystallized by the hanging-drop vapour-diffusion method from protein previously treated with 1,4-dithiothreitol. The crystals belong to the monoclinic space group C2 and diffraction data were collected to 2.8 Å resolution using a synchrotron-radiation source. Saccharomyces cerevisiae cytosolic thioredoxin peroxidase 1 (cTPxI or Tsa1) is a bifunctional enzyme with protective roles in cellular defence against oxidative and thermal stress that exhibits both peroxidase and chaperone activities. Protein overoxidation and/or high temperatures induce great changes in its quaternary structure and lead to its assembly into large complexes that possess chaperone activity. A recombinant mutant of Tsa1 from S. cerevisiae, with Cys47 substituted by serine, was overexpressed in Escherichia coli as a His{sub 6}-tagged fusion protein and purified by nickel-affinity chromatography. Crystals were obtained from protein previously treated with 1,4-dithiothreitol by the hanging-drop vapour-diffusion method using PEG 3000 as precipitant and sodium fluoride as an additive. Diffraction data were collected to 2.8 Å resolution using a synchrotron-radiation source. The crystal structure was solved by molecular-replacement methods and structure refinement is currently in progress.

  14. Evolutionary engineering of a glycerol-3-phosphate dehydrogenase-negative, acetate-reducing Saccharomyces cerevisiae strain enables anaerobic growth at high glucose concentrations

    Science.gov (United States)

    Guadalupe-Medina, Víctor; Metz, Benjamin; Oud, Bart; van Der Graaf, Charlotte M; Mans, Robert; Pronk, Jack T; van Maris, Antonius J A

    2014-01-01

    Glycerol production by Saccharomyces cerevisiae, which is required for redox-cofactor balancing in anaerobic cultures, causes yield reduction in industrial bioethanol production. Recently, glycerol formation in anaerobic S. cerevisiae cultures was eliminated by expressing Escherichia coli (acetylating) acetaldehyde dehydrogenase (encoded by mhpF) and simultaneously deleting the GPD1 and GPD2 genes encoding glycerol-3-phosphate dehydrogenase, thus coupling NADH reoxidation to reduction of acetate to ethanol. Gpd– strains are, however, sensitive to high sugar concentrations, which complicates industrial implementation of this metabolic engineering concept. In this study, laboratory evolution was used to improve osmotolerance of a Gpd– mhpF-expressing S. cerevisiae strain. Serial batch cultivation at increasing osmotic pressure enabled isolation of an evolved strain that grew anaerobically at 1 M glucose, at a specific growth rate of 0.12 h−1. The evolved strain produced glycerol at low concentrations (0.64 ± 0.33 g l−1). However, these glycerol concentrations were below 10% of those observed with a Gpd+ reference strain. Consequently, the ethanol yield on sugar increased from 79% of the theoretical maximum in the reference strain to 92% for the evolved strains. Genetic analysis indicated that osmotolerance under aerobic conditions required a single dominant chromosomal mutation, and one further mutation in the plasmid-borne mhpF gene for anaerobic growth. PMID:24004455

  15. Escherichia coli in broiler chickens with airsacculitis

    Directory of Open Access Journals (Sweden)

    Leandro S. Machado

    2014-09-01

    Full Text Available ABSTRACT. Machado L.S., do Nascimento E.R., Pereira V.L.A., Abreu D.L.C., Gouvea R. & Santos L.M.M. 2014. [Escherichia coli in broiler chickens with airsacculitis.] Escherichia coli em frangos de corte com aerossaculite. Revista Brasileira de Medicina Veterinária, 36(3:261-265, 2014. Departamento de Medicina Veterinária Preventiva e Saúde Pública, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Dr. Vital Brazil Filho 64, Vital Brazil, Niterói, RJ 24230-340, Brazil. E-mail: leandromachadovet@yahoo.com.br The Brazilian poultry industry grows each year and becomes increasingly representative in the production and export of products. The health care with poultry have accompanied and favored this evolution, however, respiratory agents that affect the weight and carcass quality, continue to cause great damage to the poultry industry. Airsacculitis is considered the main cause of total and partial condemnation of carcasses of broilers, and has been attributed to Mycoplasmosis mostly caused by Mycoplasma gallisepticum (MG and Mycoplasma synoviae (MS and Escherichia coli. The aim of this study was to relate the positivity of MG / MS and E. coli detected by PCR as a risk factor for airsacculitis in condemnation of broilers in Health Inspection Service. We studied 30 broiler poultry slaughtered in a slaughterhouse under Federal Sanitary Inspection, located in the State of Rio de Janeiro. 30 chickens were randomly collected from different lots and tracheas obtained in each PCR. DNA was extracted by phenol-chloroform method and amplified using pairs of “primer”specific for MG, MS and E. coli. Of the 30 chickens analyzed by PCR, 30% (9/30 had lesions in air sacs. None of the birds showed infection with MG and/or MS PCR, however 33.3% (3/9 birds were positive for airsacculitis iss gene from E.coli. E.coli found in broiler chickens that were negative for mycoplasma airsacculitis, implying the presence of such bacteria may be sufficient

  16. Genetic Transfer of Salmonella typhimurium and Escherichia coli Lipopolysaccharide Antigens to Escherichia coli K-12

    Science.gov (United States)

    Jones, Randall T.; Koeltzow, Donald E.; Stocker, B. A. D.

    1972-01-01

    Escherichia coli K-12 ϰ971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv+ hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his+ (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F′ factor (FS400) carrying the rfb–his region of S. typhimurium to the same two ilv+ hybrids gave similar results. LPS extracted from two ilv+,his+, factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his+ hybrids obtained from ϰ971 itself by similar HfrK9 and F′FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli ϰ971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli ϰ971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli ϰ971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his+ recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Ω8. This suggests that, although the parental E. coli K-12 strain ϰ971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units. PMID:4559827

  17. Hemolytic Porcine Intestinal Escherichia coli without Virulence-Associated Genes Typical of Intestinal Pathogenic E. coli ▿ †

    Science.gov (United States)

    Schierack, Peter; Weinreich, Joerg; Ewers, Christa; Tachu, Babila; Nicholson, Bryon; Barth, Stefanie

    2011-01-01

    Testing 1,666 fecal or intestinal samples from healthy and diarrheic pigs, we obtained hemolytic Escherichia coli isolates from 593 samples. Focusing on hemolytic E. coli isolates without virulence-associated genes (VAGs) typical for enteropathogens, we found that such isolates carried a broad variety of VAGs typical for extraintestinal pathogenic E. coli. PMID:21965399

  18. Multicellular stalk-like structures in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Engelberg, D.; Mimran, A.; Martinetto, H.; Otto, J.; Simchen, G.; Karin, M.; Fink, G.R.

    1998-01-01

    Stalk formation is a novel pattern of multicellular organization. Yeast cells which survive UV irradiation form colonies that grow vertically to form very long (0.5 to 3.0 cm) and thin (0.5 to 4 mm in diameter) multicellular structures. We describe the conditions required to obtain these stalk-like structures reproducibly in large numbers. Yeast mutants, mutated for control of cell polarity, developmental processes, UV response, and signal transduction cascades were tested and found capable of forming stalk-like structures. We suggest a model that explains the mechanism of stalk formation by mechanical environmental forces. We show that other microorganisms (Candida albicans, Schizosaccharomyces pombe, and Escherichia coli) also form stalks, suggesting that the ability to produce stalks may be a general property of microorganisms. Diploid yeast stalks sporulate at an elevated frequency, raising the possibility that the physiological role of stalks might be disseminating spores

  19. Catheter-related Saccharomyces cerevisiae Fungemia Following Saccharomyces boulardii Probiotic Treatment: In a child in intensive care unit and review of the literature

    Directory of Open Access Journals (Sweden)

    Serkan Atıcı

    2017-03-01

    Full Text Available Although Saccharomyces boulardii is usually a non-pathogenic fungus, in rare occasions it can cause invasive infection in children. We present the case of an 8-year-old patient in pediatric surgical intensive care unit who developed S. cerevisiae fungemia following probiotic treatment containing S. boulardii. Caspofungin was not effective in this case and he was treated with amphotericin B. We want to emphasize that physicians should be careful about probiotic usage in critically ill patients.

  20. Yeast-yeast interactions revealed by aromatic profile analysis of Sauvignon Blanc wine fermented by single or co-culture of non-Saccharomyces and Saccharomyces yeasts.

    Science.gov (United States)

    Sadoudi, Mohand; Tourdot-Maréchal, Raphaëlle; Rousseaux, Sandrine; Steyer, Damien; Gallardo-Chacón, Joan-Josep; Ballester, Jordi; Vichi, Stefania; Guérin-Schneider, Rémi; Caixach, Josep; Alexandre, Hervé

    2012-12-01

    There has been increasing interest in the use of selected non-Saccharomyces yeasts in co-culture with Saccharomyces cerevisiae. The main reason is that the multistarter fermentation process is thought to simulate indigenous fermentation, thus increasing wine aroma complexity while avoiding the risks linked to natural fermentation. However, multistarter fermentation is characterised by complex and largely unknown interactions between yeasts. Consequently the resulting wine quality is rather unpredictable. In order to better understand the interactions that take place between non-Saccharomyces and Saccharomyces yeasts during alcoholic fermentation, we analysed the volatile profiles of several mono-culture and co-cultures. Candida zemplinina, Torulaspora delbrueckii and Metschnikowia pulcherrima were used to conduct fermentations either in mono-culture or in co-culture with S. cerevisiae. Up to 48 volatile compounds belonging to different chemical families were quantified. For the first time, we show that C. zemplinina is a strong producer of terpenes and lactones. We demonstrate by means of multivariate analysis that different interactions exist between the co-cultures studied. We observed a synergistic effect on aromatic compound production when M. pulcherrima was in co-culture with S. cerevisiae. However a negative interaction was observed between C. zemplinina and S. cerevisiae, which resulted in a decrease in terpene and lactone content. These interactions are independent of biomass production. The aromatic profiles of T. delbrueckii and S. cerevisiae in mono-culture and in co-culture are very close, and are biomass-dependent, reflecting a neutral interaction. This study reveals that a whole family of compounds could be altered by such interactions. These results suggest that the entire metabolic pathway is affected by these interactions. Copyright © 2012 Elsevier Ltd. All rights reserved.