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Sample records for cerevisiae cell surface

  1. Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape

    OpenAIRE

    Chouhan, Raghuraj Singh; Qureshi, Anjum; Kolkar Mohammed, Javed Hussain Niazi

    2015-01-01

    In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluoresc...

  2. Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Borodina, Irina; Jensen, B. M.; Søndergaard, Ib;

    2010-01-01

    Saccharomyces cerevisiae preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp Vespula vulgaris venom: phospholipase A1, hyaluronidase and antigen 5 as the model. Results: The proteins...... were expressed on the surface as fusions with a-agglutinin complex protein AGA2. The expression was confirmed by fluorescent cytometry (FACS) after staining the cells with antibody against a C-tag attached to the C-terminal end of the allergens. Phospholipase A1 and hyaluronidase retained their...

  3. Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Poulsen Lars K

    2010-09-01

    Full Text Available Abstract Background Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast Saccharomyces cerevisiae preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp Vespula vulgaris venom: phospholipase A1, hyaluronidase and antigen 5 as the model. Results The proteins were expressed on the surface as fusions with a-agglutinin complex protein AGA2. The expression was confirmed by fluorescent cytometry (FACS after staining the cells with antibody against a C-tag attached to the C-terminal end of the allergens. Phospholipase A1 and hyaluronidase retained their enzymatic activities. Phospholipase A1 severely inhibited the growth of the yeast cells. Antigen 5 - expressing yeast cells bound IgE antibodies from wasp venom allergic patient sera but not from control sera as demonstrated by FACS. Moreover, antigen 5 - expressing yeast cells were capable of mediating allergen-specific histamine release from human basophils. Conclusions All the three major wasp venom allergens were expressed on the yeast surface. A high-level expression, which was observed only for antigen 5, was needed for detection of IgE binding by FACS and for induction of histamine release. The non-modified S. cerevisiae cells did not cause any unspecific reaction in FACS or histamine release assay despite the expression of high-mannose oligosaccharides. In perspective the yeast surface display may be used for allergen discovery from cDNA libraries and possibly for sublingual immunotherapy as the cells can serve as good adjuvant and can be produced in large amounts at a low price.

  4. Electromagnetic field influences on cell surface potential and cell division in saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The effect of electromagnetic field on cell surface potential and cell division were studied in s.cerevisiae. The strains used were, GM3 (a/gal 10,trp1, ura4, met 8, ade 5,7,les1, ilvl,arol D, suc-mal, cupr.)and ural (a/urap+w-c 321, R E 221, R) an electromagnetic field (h) .O.I.T, cell resistance (R) increased from 0.158 MΩ to 0.200 M Ω through 5 min. The magnetic field (MF) were switching off. The resistance spontaneously increased reaching 1.000 M Ω at the 9 Th min. However, slowly decrease occurred and reaching 0.560 M Omega at the 15 Th min. By using the MF after 15 min., the resistance value reaching 0.180 M OMEGA, through 15-25 min and cell potential (V) ranged between 130-240 mV. Cell culture, of two strains (same mating type) was used, the resistance, R., was 4000 M Ω and V; 600 mV with two cycles min, R; reached 3200 M Ω. On further cycle of (H) led to a huge sudden decrease of R; 0.176 M Ω the cell numbers were depended, upon the cell potential, due to the application of (H). For the first strain used, cell number decreased from 2x106 cells/ml to 1.5x106 cells/ml and from 2.1x108 cells/ml to 1.7x108 cells/ml after 5 min exposure to (H) for culture incubated at 30 degree on log and stationary phases respectively. While, the cell number in ural was decreased from 3.5x106 cells/ml and from 1.78x108 cells/ ml. to 1.71x108 cells/ml through 5 min exposure to (H) for culture incubated at 30 degree on log and stationary phases respectively

  5. Cell Surface Display of Four Types of Solanum nigrum Metallothionein on Saccharomyces cerevisiae for Biosorption of Cadmium.

    Science.gov (United States)

    Wei, Qinguo; Zhang, Honghai; Guo, Dongge; Ma, Shisheng

    2016-05-28

    We displayed four types of Solanum nigrum metallothionein (SMT) for the first time on the surface of Saccharomyces cerevisiae using an α-agglutinin-based display system. The SMT genes were amplified by RT-PCR. The plasmid pYES2 was used to construct the expression vector. Transformed yeast strains were confirmed by PCR amplification and custom sequencing. Surface-expressed metallothioneins were indirectly indicated by the enhanced cadmium sorption capacity. Flame atomic absorption spectrophotometry was used to examine the concentration of Cd(2+) in this study. The transformed yeast strains showed much higher resistance ability to Cd(2+) compared with the control. Strikingly, their Cd(2+) accumulation was almost twice as much as that of the wild-type yeast cells. Furthermore, surface-engineered yeast strains could effectively adsorb ultra-trace cadmium and accumulate Cd(2+) under a wide range of pH levels, from 3 to 7, without disturbing the Cu(2+) and Hg(2+). Four types of surfaceengineered Saccharomyces cerevisiae strains were constructed and they could be used to purify Cd(2+)-contaminated water and adsorb ultra-trace cadmium effectively. The surface-engineered Saccharomyces cerevisiae strains would be useful tools for the bioremediation and biosorption of environmental cadmium contaminants. PMID:26838339

  6. Display of phytase on the cell surface of Saccharomyces cerevisiae to degrade phytate phosphorus and improve bioethanol production.

    Science.gov (United States)

    Chen, Xianzhong; Xiao, Yan; Shen, Wei; Govender, Algasan; Zhang, Liang; Fan, You; Wang, Zhengxiang

    2016-03-01

    Currently, development of biofuels as an alternative fuel has gained much attention due to resource and environmental challenges. Bioethanol is one of most important and dominant biofuels, and production using corn or cassava as raw materials has become a prominent technology. However, phytate contained in the raw material not only decreases the efficiency of ethanol production, but also leads to an increase in the discharge of phosphorus, thus impacting on the environment. In this study, to decrease phytate and its phosphorus content in an ethanol fermentation process, Saccharomyces cerevisiae was engineered through a surface-displaying system utilizing the C-terminal half of the yeast α-agglutinin protein. The recombinant yeast strain, PHY, was constructed by successfully displaying phytase on the surface of cells, and enzyme activity reached 6.4 U/g wet biomass weight. Ethanol productions using various strains were compared, and the results demonstrated that the specific growth rate and average fermentation rate of the PHY strain were higher 20 and 18 %, respectively, compared to the control strain S. cerevisiae CICIMY0086, in a 5-L bioreactor process by simultaneous saccharification and fermentation. More importantly, the phytate phosphorus concentration decreased by 89.8 % and free phosphorus concentration increased by 142.9 % in dry vinasse compared to the control in a 5-L bioreactor. In summary, we constructed a recombinant S. cerevisiae strain displaying phytase on the cell surface, which could improve ethanol production performance and effectively reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate. PMID:26610799

  7. Comparison of cell wall proteins of Saccharomyces cerevisiae as anchors for cell surface expression of heterologous proteins.

    OpenAIRE

    van der Vaart, J. M.; te Biesebeke, R; Chapman, J.W.; Toschka, H Y; Klis, F M; Verrips, C. T.

    1997-01-01

    The carboxyl-terminal regions of five cell wall proteins (Cwp1p, Cwp2p, Ag alpha 1p, Tip1p, and Flo1p) and three potential cell wall proteins (Sed1p, YCR89w, and Tir1p) all proved capable of immobilizing alpha-galactosidase in the cell wall of Saccharomyces cerevisiae. The fraction of the total amount of fusion protein that was localized to the cell wall varied depending on the anchor domain used. The highest proportion of cell wall incorporation was achieved with Cwp2p, Ag alpha 1p, or Sed1p...

  8. Cell surface engineering of Saccharomyces cerevisiae combined with membrane separation technology for xylitol production from rice straw hydrolysate.

    Science.gov (United States)

    Guirimand, Gregory; Sasaki, Kengo; Inokuma, Kentaro; Bamba, Takahiro; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-04-01

    Xylitol, a value-added polyol deriving from D-xylose, is widely used in both the food and pharmaceutical industries. Despite extensive studies aiming to streamline the production of xylitol, the manufacturing cost of this product remains high while demand is constantly growing worldwide. Biotechnological production of xylitol from lignocellulosic waste may constitute an advantageous and sustainable option to address this issue. However, to date, there have been few reports of biomass conversion to xylitol. In the present study, xylitol was directly produced from rice straw hydrolysate using a recombinant Saccharomyces cerevisiae YPH499 strain expressing cytosolic xylose reductase (XR), along with β-glucosidase (BGL), xylosidase (XYL), and xylanase (XYN) enzymes (co-)displayed on the cell surface; xylitol production by this strain did not require addition of any commercial enzymes. All of these enzymes contributed to the consolidated bioprocessing (CBP) of the lignocellulosic hydrolysate to xylitol to produce 5.8 g/L xylitol with 79.5 % of theoretical yield from xylose contained in the biomass. Furthermore, nanofiltration of the rice straw hydrolysate provided removal of fermentation inhibitors while simultaneously increasing sugar concentrations, facilitating high concentration xylitol production (37.9 g/L) in the CBP. This study is the first report (to our knowledge) of the combination of cell surface engineering approach and membrane separation technology for xylitol production, which could be extended to further industrial applications. PMID:26631184

  9. 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...... cues, cell-to-cell variation and niches in S. cerevisiae biofilm. Being closely related to Candida species, S. cerevisiae is a model to investigate biofilms of pathogenic yeast....

  10. Comparison of cell wall proteins of Saccharomyces cerevisiae as anchors for cell surface expression of heterologous proteins.

    Science.gov (United States)

    Van der Vaart, J M; te Biesebeke, R; Chapman, J W; Toschka, H Y; Klis, F M; Verrips, C T

    1997-01-01

    The carboxyl-terminal regions of five cell wall proteins (Cwp1p, Cwp2p, Ag alpha 1p, Tip1p, and Flo1p) and three potential cell wall proteins (Sed1p, YCR89w, and Tir1p) all proved capable of immobilizing alpha-galactosidase in the cell wall of Saccharomyces cerevisiae. The fraction of the total amount of fusion protein that was localized to the cell wall varied depending on the anchor domain used. The highest proportion of cell wall incorporation was achieved with Cwp2p, Ag alpha 1p, or Sed1p as an anchor. Although 80% of these fusion proteins were incorporated in the cell wall, the total production of alpha-galactosidase-Ag alpha 1p was sixfold lower than that of alpha-galactosidase-Cwp2p and eightfold lower than that of alpha-galactosidase-Sed1p. Differences in mRNA levels were not responsible for this discrepancy, nor was an intracellular accumulation of alpha-galactosidase-Ag alpha 1p detectable. A lower translation efficiency of the alpha-galactosidase-AG alpha 1 fusion construct is most likely to be responsible for the low level of protein production. alpha-Galactosidase immobilized by the carboxyl-terminal 67 amino acids of Cwp2p was most effective in the hydrolysis of the high-molecular-weight substrate guar gum from Cyamopsis tetragonoloba. This indicates that the use of a large anchoring domain does not necessarily result in a better exposure of the immobilized enzyme to the exterior of the yeast cell. PMID:9023939

  11. Expression of Pneumocystis jirovecii Major Surface Glycoprotein in Saccharomyces cerevisiae

    OpenAIRE

    Kutty, Geetha; England, Katherine J.; Kovacs, Joseph A.

    2013-01-01

    The major surface glycoprotein (Msg), which is the most abundant protein expressed on the cell surface of Pneumocystis organisms, plays an important role in the attachment of this organism to epithelial cells and macrophages. In the present study, we expressed Pneumocystis jirovecii Msg in Saccharomyces cerevisiae, a phylogenetically related organism. Full-length P. jirovecii Msg was expressed with a DNA construct that used codons optimized for expression in yeast. Unlike in Pneumocystis orga...

  12. Cell Wall Assembly in Saccharomyces cerevisiae

    OpenAIRE

    Lesage, Guillaume; Bussey, Howard

    2006-01-01

    An extracellular matrix composed of a layered meshwork of β-glucans, chitin, and mannoproteins encapsulates cells of the yeast Saccharomyces cerevisiae. This organelle determines cellular morphology and plays a critical role in maintaining cell integrity during cell growth and division, under stress conditions, upon cell fusion in mating, and in the durable ascospore cell wall. Here we assess recent progress in understanding the molecular biology and biochemistry of cell wall synthesis and it...

  13. Glycolipids of Saccharomyces cerevisiae Cell

    Directory of Open Access Journals (Sweden)

    Renuka Malhotra

    2005-01-01

    Full Text Available Total lipids of Saccharomyces cerevisiae were isolated by chloroform and methanol (2:1. Glycolipids were separated from total lipids by silicic acid chromatography. Glycolipid’s constituent sugars and fatty acids were analyzed by using Gas Liquid Chromatography. Galactose was the prominent sugar followed by mannose. Relative concentrations of fucose, mannose, galactose and glucose in the glycolipid were 5.3, 35.2, 55.1 and 4.2%. 16:0, 18:0, 18:1, 18:2 and 18:3 were the major fatty acids of the total glycolipids. Oleic acid was the dominating fatty acid followed by linoliec acid. They were separated into different fractions by using DEAE-Sephadex ion exchange chromatography. Glycolipids were fractionated and identified as cerebrosides, ceramide polyhexosides, sulfatides, monoglucosyldiglycerides and diglucosyldiglycerides. Ceramide polyhexosides were present in higher concentration as compared to other fractions.

  14. Biosorption of uranium by Saccharomyces cerevisiae and surface interactions under culture conditions.

    Science.gov (United States)

    Liu, Mingxue; Dong, Faqin; Yan, Xiuying; Zeng, Wenming; Hou, Liangyu; Pang, Xiaofeng

    2010-11-01

    Few studies have focused on biosorption by microorganisms under culture conditions. To explore the biosorption of uranium by Saccharomyces cerevisiae under culture conditions, the S. cerevisiae growth curve, biosorption capacity and surface interaction under batch culture conditions were investigated in this study. The growth curve showed that uranium (yeast cell surfaces, as well as culture medium, and produced uranium precipitate on cell surfaces. Fourier transformed infrared spectra revealed that cell walls were the major sorption sites, and -O--H, -C==O and -PO(2-) contributed to the major binding groups. PMID:20599379

  15. Microbial cells as biosorbents for heavy metals: accumulation of Uranium by Saccharomyces cerevisiae and Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Uranium accumulated extracellularly on the surfaces of Saccharomyces cerevisiae cells. The rate and extent of accumulation were subject to environmental parameters, such as pH, temperature, and interference by certain anions and cations. Uranium accumulation by Pseudomonas aeruginosa occurred intracellularly and was extremely rapid (<10 s), and no response to environmental parameters could be detected. Metabolism was not required for metal uptake by either organism. Cell-bound uranium reached a concentration of 10 to 15% of the dry cell weight, but only 32% of the S. cerevisiae cells and 44% of the P. aeruginosa cells within a given population possessed visible uranium deposits when examined by electron microscopy. Rates of uranium uptake by S. cerevisiae were increased by chemical pretreatment of the cells. Uranium could be removed chemically from S. cerevisiae cells, and the cells could then be reused as a biosorbent

  16. Effects of spaceflight on polysaccharides of Saccharomyces cerevisiae cell wall.

    Science.gov (United States)

    Liu, Hong-Zhi; Wang, Qiang; Liu, Xiao-Yong; Tan, Sze-Sze

    2008-12-01

    Freeze-dried samples of four Saccharomyces cerevisiae strains, namely, FL01, FL03, 2.0016, and 2.1424, were subjected to spaceflight. After the satellite's landing on Earth, the samples were recovered and changes in yeast cell wall were analyzed. Spaceflight strains of all S. cerevisiae strains showed significant changes in cell wall thickness (P growth curve analysis showed spaceflight S. cerevisiae 2.0016 had a faster growth rate, shorter lag phase periods, higher final biomass, and higher content of beta-glucan. Genetic stability analysis showed that prolonged subculturing of spaceflight strain S. cerevisiae 2.0016 did not lead to the appearance of variants, indicating that the genetic stability of S. cerevisiae 2.0016 mutant could be sufficient for its exploitation of beta-glucan production. PMID:18797865

  17. Saccharomyces cerevisiae SHSY detoxifies petroleum n-alkanes by an induced CYP52A58 and an enhanced order in cell surface hydrophobicity.

    Science.gov (United States)

    Hanano, Abdulsamie; Shaban, Mouhnad; Almousally, Ibrahem; Al-Ktaifani, Mahmoud

    2015-09-01

    Environmental hydrocarbon contamination has a serious hazard to human health. Alkanes, the major component of hydrocarbons, can be consumed by various species of yeast. We previously identified a new strain SHSY of Saccharomyces cerevisiae with a remarkable ability to utilize the petroleum crude-oil (PCO) in aqueous solution. The current study demonstrated that the n-alkanes-assimilation activity of S. cerevisiae SHSY was related to an induced microsomal protein of 59 kDa approximately. The identified ORF encoded a protein of 517 amino acids and shared 93% sequence identity with an alkane-inducible hydroxylase CYP52A53 isolated from Scheffersomyces stipitis CBS. It was therefore referred as CYP52A58. The catalytic activity of the recombinant CYP52A58 was confirmed by the hydroxylation of n-alkanes, it showed an optimal mono-terminal hydroxylation activity toward n-hexadecane. Moreover, the ability of the yeast to use n-alkanes was accompanied with an increasing level in cell wall mannoproteins. Two differential protein bands were detected in the mannoproteins extracted from PCO-grown yeast. In parallel, a significant increase in the fatty acids content with a high degree of unsaturation was subsequently detected in the PCO-grown yeast. This study characterizes a safe and potential microorganism to remove n-alkanes from the aquatic environment. PMID:25434275

  18. Study on cell surface display of β-amylase on Saccharomces cerevisiae and its practical properties%酿酒酵母表面展示β-淀粉酶及其酶学性质研究

    Institute of Scientific and Technical Information of China (English)

    杨华; 樊游; 沈微; 石贵阳; SurenSingh; 王正祥

    2012-01-01

    通过PCR技术扩增来源于大麦的β-淀粉酶基因,将其与酿酒酵母细胞壁蛋白d凝集素基因在读框内融合,构建得到表面展示载体pBA-AG,进一步将该重组质粒通过遗传转化,整合到酿酒酵母W303-1A的染色体中,获得了β-淀粉酶经过仅凝集素锚定信号结合到细胞壁上的重组酵母。重组酵母表面展示的β-淀粉酶活力为131U/g干细胞。对展示的β-淀粉酶酶学性质研究表明,其最适反应温度为50℃,最适作用pH为5.0,与游离酶相比,其温度稳定性和pH稳定性均得到提高。本研究利用α凝集素系统首次将β-淀粉酶成功展示在酿酒酵母表面,为以酿酒酵母为基础的全细胞催化剂研究与应用打下了一定基础.%The gene encoding mature β-amylase from barley was cloned via PCR and then fused with the α-agglutinin of Saccharomyces cerevisiae in frame and a recombinant plasmid named pBA-AG was constructed. Recombinant plasmid pBA-AG was successfully transformed into S. cerevisiae W303-1A and was integrated into the chromosome. The expressed β-amylase was successfully anchored on the cell wall and displayed on the surface of recombinant S. cerevisiae. The measured activity of displayed β-amylase was 131U/g dry cells. The optimal temperature and pH for displayed β-amylase was 50℃ and 5.0,respectively. The recombinant β-amylase displayed on cell surface exhibited enhanced thermostability compared to free enzyme. In this study,the firstly constructed recombinant S. cerevisiae strain displaying β-amylase on the cell surface with a-agglutinin as carrier protein showed a great potential for industrial application as a whole-cell biocatalyst.

  19. Efficient display of active lipase LipB52 with a Pichia pastoris cell surface display system and comparison with the LipB52 displayed on Saccharomyces cerevisiae cell surface

    OpenAIRE

    Ma Yushu; Tao Xingyi; Ren Ren; Gao Bei; Jiang Zhengbing; Wei Dongzhi

    2008-01-01

    Abstract Background For industrial bioconversion processes, the utilization of surface-displayed lipase in the form of whole-cell biocatalysts is more advantageous, because the enzymes are displayed on the cell surface spontaneously, regarded as immobilized enzymes. Results Two Pichia pastoris cell surface display vectors based on the flocculation functional domain of FLO with its own secretion signal sequence or the α-factor secretion signal sequence were constructed respectively. The lipase...

  20. Surface display of malolactic enzyme from Oenococcus oeni on Saccharomyces cerevisiae.

    Science.gov (United States)

    Zhang, Xiuyan; Hou, Xiaoyan; Liang, Fang; Chen, Fusheng; Wang, Xiaohong

    2013-04-01

    In order to display malolactic enzyme (MLE) on the cell surface of Saccharomyces cerevisiae, a yeast cell surface display plasmid pADH1-AGG was constructed by fusing the α-factor signal encoding sequence (267 bp) and the C-terminal half of α-agglutinin encoding sequence (1,645 bp) into the plasmid pADH1. The pADH1-AGG could successfully express and anchor the enhanced green fluorescent protein (EGFP) onto the yeast cell surface when the EGFP was used to verify its function. Then the pADH1-MLE was constructed by inserting the MLE encoding sequence (1,600 bp) into the pADH1-AGG and introduced into S. cerevisiae cells. The positive strain carrying pADH1-MLE was confirmed by use of the 6× His monoclonal antibody and fluorescein isothiocyanate-conjugated goat anti-mouse IgG. All results indicated that the MLE was displayed successfully on the cell surface of positive transformant. The MLE activity of genetically engineered yeast strain could turn 21.11 % L-malate into lactic acid after 12 h reaction with L-malate. The constructed yeast strain might be used to conduct malolactic fermentation (MLF) in wine to solve the important issues of sluggish MLF, microbial spoilage, and adverse metabolic substances produced by the lactic acid bacteria. PMID:23446978

  1. Symmetric cell division in pseudohyphae of the yeast Saccharomyces cerevisiae.

    OpenAIRE

    Kron, S J; Styles, C. A.; Fink, G R

    1994-01-01

    Laboratory strains of Saccharomyces cerevisiae are dimorphic; in response to nitrogen starvation they switch from a yeast form (YF) to a filamentous pseudohyphal (PH) form. Time-lapse video microscopy of dividing cells reveals that YF and PH cells differ in their cell cycles and budding polarity. The YF cell cycle is controlled at the G1/S transition by the cell-size checkpoint Start. YF cells divide asymmetrically, producing small daughters from full-sized mothers. As a result, mothers and d...

  2. Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    António Rego

    2014-08-01

    Full Text Available Acetic acid triggers apoptotic cell death in Saccharomyces cerevisiae, similar to mammalian apoptosis. To uncover novel regulators of this process, we analyzed whether impairing MAPK signaling affected acetic acid-induced apoptosis and found the mating-pheromone response and, especially, the cell wall integrity pathways were the major mediators, especially the latter, which we characterized further. Screening downstream effectors of this pathway, namely targets of the transcription factor Rlm1p, highlighted decreased cell wall remodeling as particularly important for acetic acid resistance. Modulation of cell surface dynamics therefore emerges as a powerful strategy to increase acetic acid resistance, with potential application in industrial fermentations using yeast, and in biomedicine to exploit the higher sensitivity of colorectal carcinoma cells to apoptosis induced by acetate produced by intestinal propionibacteria.

  3. 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

  4. Cell Wall Integrity Signaling in Saccharomyces cerevisiae

    OpenAIRE

    Levin, David E.

    2005-01-01

    The yeast cell wall is a highly dynamic structure that is responsible for protecting the cell from rapid changes in external osmotic potential. The wall is also critical for cell expansion during growth and morphogenesis. This review discusses recent advances in understanding the various signal transduction pathways that allow cells to monitor the state of the cell wall and respond to environmental challenges to this structure. The cell wall integrity signaling pathway controlled by the small...

  5. CRISPR-Cas9 Genome Engineering in Saccharomyces cerevisiae Cells.

    Science.gov (United States)

    Ryan, Owen W; Poddar, Snigdha; Cate, Jamie H D

    2016-01-01

    This protocol describes a method for CRISPR-Cas9-mediated genome editing that results in scarless and marker-free integrations of DNA into Saccharomyces cerevisiae genomes. DNA integration results from cotransforming (1) a single plasmid (pCAS) that coexpresses the Cas9 endonuclease and a uniquely engineered single guide RNA (sgRNA) expression cassette and (2) a linear DNA molecule that is used to repair the chromosomal DNA damage by homology-directed repair. For target specificity, the pCAS plasmid requires only a single cloning modification: replacing the 20-bp guide RNA sequence within the sgRNA cassette. This CRISPR-Cas9 protocol includes methods for (1) cloning the unique target sequence into pCAS, (2) assembly of the double-stranded DNA repair oligonucleotides, and (3) cotransformation of pCAS and linear repair DNA into yeast cells. The protocol is technically facile and requires no special equipment. It can be used in any S. cerevisiae strain, including industrial polyploid isolates. Therefore, this CRISPR-Cas9-based DNA integration protocol is achievable by virtually any yeast genetics and molecular biology laboratory. PMID:27250940

  6. 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...

  7. Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

    OpenAIRE

    Brewer, B J; Chlebowicz-Sledziewska, E; Fangman, W L

    1984-01-01

    During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic st...

  8. 酿酒酵母细胞表面展示技术在燃料乙醇生产中的应用及研究进展%Development and application of Saccharomyces cerevisiae cell-surface display for bioethanol production

    Institute of Scientific and Technical Information of China (English)

    杨非; 曹萌; 金怡; 杨秀山; 田沈

    2012-01-01

    酿酒酵母Saccharomyces cerevisiae细胞表面展示表达系统是一种固定化表达异源蛋白质的真核展示系统,具有糖基化作用及蛋白翻译后折叠等优势,更利于基因工程操作.近年来,酵母细胞表面工程作为一种新兴策略来固定化淀粉水解酶、纤维素水解酶以及木聚糖降解酶,从而应用于燃料乙醇的生产.文中着重介绍了酵母细胞表面展示系统的基本原理、研究现状以及在生物乙醇生产中的应用前景及所面临的挑战.%Saccharomyces cerevisiae is useful as a host for genetic engineering, since it allows the folding and glycosylation of expressed heterologous eukaryotic proteins and can be subjected to many genetic manipulations. Recent advancements in the yeast cell surface engineering developed strategies to genetically immobilize amylolytic, cellulolytic and xylanolytic enzymes on yeast cell surface for the production of fuel ethanol from biomass. We reviewed the basic principle and progress of S. cerevisiae cell-surface engineering and gave an insight into the recent technological developments in the production of bioethanol using surface engineered yeast.

  9. ACE2 is required for daughter cell-specific G1 delay in Saccharomyces cerevisiae

    OpenAIRE

    Laabs, Tracy L.; Markwardt, David D.; Slattery, Matthew G.; Newcomb, Laura L.; Stillman, David J.; Heideman, Warren

    2003-01-01

    Saccharomyces cerevisiae cells reproduce by budding to yield a mother cell and a smaller daughter cell. Although both mother and daughter begin G1 simultaneously, the mother cell progresses through G1 more rapidly. Daughter cell G1 delay has long been thought to be due to a requirement for attaining a certain critical cell size before passing the commitment point in the cell cycle known as START. We present an alternative model in which the daughter cell-specific Ace2 ...

  10. Human Enterovirus 71 Protein Displayed on the Surface of Saccharomyces cerevisiae as an Oral Vaccine.

    Science.gov (United States)

    Zhang, Congdang; Wang, Yi; Ma, Shuzhi; Li, Leike; Chen, Liyun; Yan, Huimin; Peng, Tao

    2016-06-01

    Human enterovirus 71 (EV-A71), a major agent of hand, foot, and mouth disease, has become an important public health issue in recent years. No effective antiviral or vaccines against EV-A71 infection are currently available. EV-A71 infection intrudes bodies through the gastric mucosal surface and it is necessary to enhance mucosal immune response to protect children from these pathogens. Recently, the majority of EV-A71 vaccine candidates have been developed for parenteral immunization. However, parenteral vaccine candidates often induce poor mucosal responses. On the other hand, oral vaccines could induce effective mucosal and systemic immunity, and could be easily and safely administered. Thus, proper oral vaccines have attached more interest compared with parenteral vaccine. In this study, the major immunogenic capsid protein of EV-A71 was displayed on the surface of Saccharomyces cerevisiae. Oral immunization of mice with surface-displayed VP1 S. cerevisiae induced systemic humoral and mucosal immune responses, including virus-neutralizing titers, VP1-specific antibody, and the induction of Th1 immune responses in the spleen. Furthermore, oral immunization of mother mice with surface-displayed VP1 S. cerevisiae conferred protection to neonatal mice against the lethal EV-A71 infection. Furthermore, we observed that multiple boost immunization as well as higher immunization dosage could induce higher EV-A71-specific immune response. Our results demonstrated that surface-displayed VP1 S. cerevisiae could be used as potential oral vaccine against EV-A71 infection. PMID:27259043

  11. Identification of amino acids involved in the Flo11p-mediated adhesion of Saccharomyces cerevisiae to a polystyrene surface using phage display with competitive elution

    DEFF Research Database (Denmark)

    Mortensen, Henrik Dam; Dupont, Kitt; Jespersen, Lene;

    2007-01-01

    . cerevisiae FLO11 wild-type (TBR1) cells had a higher consensus than those from competitive panning with S. cerevisiae flo11¿ mutant (TBR5) cells, suggesting that the wild-type cells interact with the plastic surface in a stronger and more similar way than the mutant cells. Tryptophan and proline were more...... a phage with a hydrophobic peptide containing no tryptophan and only two proline residues. Conclusions: Our results suggest a key role of tryptophan and proline in the hydrophobic interactions between Flo11p on the S. cerevisiae cell surface and the PolySorp surface. Significance and Impact of the Study......: Our study may contribute to the development of novel strategies to limit yeast infections in hospitals and other medical environments....

  12. Increasing ethanol productivity during xylose fermentation by cell recycling of recombinant Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Roca, Christophe Francois Aime; Olsson, Lisbeth

    2003-01-01

    The influence of cell recycling of xylose-fermenting Saccharomyces cerevisiae TMB3001 was investigated during continuous cultivation on a xylose-glucose mixture. By using cell recycling at the dilution rate (D) of 0.05 h(-1), the cell-mass concentration could be increased from 2.2 g l(-1) to 22 g l...

  13. Daughter cells of Saccharomyces cerevisiae from old mothers display a reduced life span

    OpenAIRE

    1994-01-01

    The yeast Saccharomyces cerevisiae typically divides asymmetrically to give a large mother cell and a smaller daughter cell. As mother cells become old, they enlarge and produce daughter cells that are larger than daughters derived from young mother cells. We found that occasional daughter cells were indistinguishable in size from their mothers, giving rise to a symmetric division. The frequency of symmetric divisions became greater as mother cells aged and reached a maximum occurrence of 30%...

  14. Monitoring of Saccharomyces cerevisiae cell proliferation on thiol-modified planar gold microelectrodes using impedance spectroscopy

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Spegel, Christer F; Kostesha, Natalie;

    2008-01-01

    value of R,, showed over 560% increase with respect to the value obtained on the same thiol-modified electrode without cells. It was demonstrated that real-time monitoring of S. cerevisiae proliferation, with frequency-normalized imaginary admittance (real capacitance) as the indicator, was possible......An impedance spectroscopic study of the interaction between thiol-modified Au electrodes and Saccharomyces cerevisiae of strain EBY44 revealed that the cells formed an integral part of the interface, modulating the capacitive properties until a complete monolayer was obtained, whereas the charge...... transfer resistance (R-ct) to the redox process of [Fe(CN)6](3-14-) showed a linear relationship to the number of cells even beyond the monolayer coverage. R,, showed strong pH dependence upon increasing the pH of the utilized buffer to 7.2. Upon addition of S. cerevisiae cells at pH 7.2, the obtained...

  15. Overexpression of human virus surface glycoprotein precursors induces cytosolic unfolded protein response in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Sasnauskas Kęstutis

    2011-05-01

    Full Text Available Abstract Background The expression of human virus surface proteins, as well as other mammalian glycoproteins, is much more efficient in cells of higher eukaryotes rather than yeasts. The limitations to high-level expression of active viral surface glycoproteins in yeast are not well understood. To identify possible bottlenecks we performed a detailed study on overexpression of recombinant mumps hemagglutinin-neuraminidase (MuHN and measles hemagglutinin (MeH in yeast Saccharomyces cerevisiae, combining the analysis of recombinant proteins with a proteomic approach. Results Overexpressed recombinant MuHN and MeH proteins were present in large aggregates, were inactive and totally insoluble under native conditions. Moreover, the majority of recombinant protein was found in immature form of non-glycosylated precursors. Fractionation of yeast lysates revealed that the core of viral surface protein aggregates consists of MuHN or MeH disulfide-linked multimers involving eukaryotic translation elongation factor 1A (eEF1A and is closely associated with small heat shock proteins (sHsps that can be removed only under denaturing conditions. Complexes of large Hsps seem to be bound to aggregate core peripherally as they can be easily removed at high salt concentrations. Proteomic analysis revealed that the accumulation of unglycosylated viral protein precursors results in specific cytosolic unfolded protein response (UPR-Cyto in yeast cells, characterized by different action and regulation of small Hsps versus large chaperones of Hsp70, Hsp90 and Hsp110 families. In contrast to most environmental stresses, in the response to synthesis of recombinant MuHN and MeH, only the large Hsps were upregulated whereas sHsps were not. Interestingly, the amount of eEF1A was also increased during this stress response. Conclusions Inefficient translocation of MuHN and MeH precursors through ER membrane is a bottleneck for high-level expression in yeast. Overexpression of

  16. Reactivation of UV-irradiated plasmid transforming DNA by cells of yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Bekker, M.L.; Kozhina, T.N.; Smolina, V.S. (AN SSSR, Leningrad. Inst. Yadernoj Fiziki)

    1983-01-01

    Data revealing that cells of yeast Sccharomyces cerevisiae can reactivate transforming plasmid DNA after UV-radiation are given, this phenomenon at least partially depends on the system of exision reparation of master cells. Dependence of yeast survival rate and yield of yeast transformants on the UV-radiation dose of transforming DNA plasmid is disclosed.

  17. Members of the Hsp70 family of proteins in the cell wall of Saccharomyces cerevisiae.

    OpenAIRE

    López-Ribot, J L; Chaffin, W L

    1996-01-01

    Western blot (immunoblot) analysis of cell wall and cytosolic extracts obtained from parental and ssa1 and ssa2 single- and double-mutant strains of Saccharomyces cerevisiae showed that the heat shock protein 70 (Hsp70) products of these genes, previously thought to be restricted to the cell interior, are also present in the cell wall. A cell wall location was further confirmed by indirect immunofluorescence with intact cells and biotinylation of extracellular Hsp70. Hsp70s have been implicat...

  18. Identification of Proteins Whose Synthesis Is Modulated During the Cell Cycle of Saccharomyces cerevisiae

    OpenAIRE

    Lörincz, Attila T.; Miller, Mark J.; Xuong, Nguyen-Huu; Geiduschek, E. Peter

    1982-01-01

    We examined the synthesis and turnover of individual proteins in the Saccharomyces cerevisiae cell cycle. Proteins were pulse-labeled with radioactive isotope (35S or 14C) in cells at discrete cycle stages and then resolved on two-dimensional gels and analyzed by a semiautomatic procedure for quantitating gel electropherogram-autoradiographs. The cells were obtained by one of three methods: (i) isolation of synchronous subpopulations of growing cells by zonal centrifugation; (ii) fractionatio...

  19. Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingtao [School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Xiaoxin [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Qi, E-mail: qili@imr.ac.cn [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Shang, Jian Ku [Environment Functional Materials Division, Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2015-04-01

    An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack. - Highlights: • Palladium-modified nitrogen-doped titanium oxidephotocatalyst (TiON/PdO) • Effective visible-light photocatalytic disinfection of yeast cells by TiON/PdO • Real time, in situ observation technique was developed for photocatalytic disinfection. • The fluorescence/phase contrast microscope with a photocatalytic micro-reactor • Yeast cell disinfection happened before the cell structure collapsed.

  20. Real time, in situ observation of the photocatalytic inactivation of Saccharomyces cerevisiae cells

    International Nuclear Information System (INIS)

    An in situ microscopy technique was developed to observe in real time the photocatalytic inactivation process of Saccharomyces cerevisiae (S. cerevisiae) cells by palladium-modified nitrogen-doped titanium oxide (TiON/PdO) under visible light illumination. The technique was based on building a photocatalytic micro-reactor on the sample stage of a fluorescence/phase contrast microscopy capable of simultaneously providing the optical excitation to activate the photocatalyst in the micro-reactor and the illumination to acquire phase contrast images of the cells undergoing the photocatalytic inactivation process. Using TiON/PdO as an example, the technique revealed for the first time the vacuolar activities inside S. cerevisiae cells subjected to a visible light photocatalytic inactivation. The vacuoles responded to the photocatalytic attack by the first expansion of the vacuolar volume and then contraction, before the vacuole disappeared and the cell structure collapsed. Consistent with the aggregate behavior observed from the cell culture experiments, the transition in the vacuolar volume provided clear evidence that photocatalytic disinfection of S. cerevisiae cells started with an initiation period in which cells struggled to offset the photocatalytic damage and moved rapidly after the photocatalytic damage overwhelmed the defense mechanisms of the cells against oxidative attack. - Highlights: • Palladium-modified nitrogen-doped titanium oxidephotocatalyst (TiON/PdO) • Effective visible-light photocatalytic disinfection of yeast cells by TiON/PdO • Real time, in situ observation technique was developed for photocatalytic disinfection. • The fluorescence/phase contrast microscope with a photocatalytic micro-reactor • Yeast cell disinfection happened before the cell structure collapsed

  1. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid

    Directory of Open Access Journals (Sweden)

    Sergio eGiannattasio

    2013-02-01

    Full Text Available Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications.

  2. Analysis of Distributed Growth of Saccharomyces cerevisiae Cells Immobilized in Polyacrylamide Gel

    OpenAIRE

    Burrill, Hugh N.; Bell, Laurel E.; Greenfield, Paul F.; Do, Duong D.

    1983-01-01

    A technique is described for the quantitative determination of the distributed growth of Saccharomyces cerevisiae immobilized in polyacrylamide gel. Gel specimens were embedded in paraffin or gelatin and paraffin before sectioning and staining. Photomicrographs of specimen sections were enlarged, and cell microcolony volumes were determined as a function of position in the gel by grid transparency analysis. Overall cell densities within the gel were calculated for a quantitative comparison wi...

  3. Effects of cell entrapment in Ca-alginate on the metabolism of yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Saccharomyces cerevisiae cells grown in suspension have been immobilized in calcium-alginate beads. Fermentation rates and intracellular composition have been determined under nongrowing conditions in these Ca-alginate entrapped cells and for identical cells in suspension. Glucose uptake and ethanol and glycerol production are approximately two times faster in immobilized cells than in suspended cells. Intermediate metabolite levels such as fructose-1,6-diphosphate, glucose-6-phosphate and 3-phosphoglycerate have been determined by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy under glucose fermenting conditions. Carbon-13 NMR shows an increase in polysaccharide production in immobilized cells. S. cerevisiae cells grown within a Ca-alginate matrix have a specific growth rate 40% lower than the growth rate of similar cells cultivated in suspension. Alginate-grown cells have been used to compare glucose fermentation under nongrowing conditions in suspended and Ca-entrapped cells. Fermentation rate is higher in immobilized cells than in suspended cells. The observed differences in intracellular components between suspended and immobilized cells are qualitatively similar to the differences observed for cells grown in suspension. Ethanol production rate is 2.7 times faster in immobilized alginate-grown cells than in suspended suspension-grown cells

  4. Acid stress adaptation protects saccharomyces cerevisiae from acetic acid-induced programme cell death

    OpenAIRE

    Giannattasio, Sergio; Guaragnella, Nicoletta; Côrte-Real, Manuela; Passarella, Salvatore; Marra, Ersilia

    2005-01-01

    In this work evidence is presented that acid stress adaptation protects Saccharomyces cerevisiae from acetic acid-mediated programmed cell death. Exponential-phase yeast cells, non-adapted or adapted to acid stress by 30 min incubation in rich medium set at pH 3.0 with HCl, have been exposed to increasing concentrations of acetic acid and time course changes of cell viability have been assessed. Adapted cells, in contrast to non-adapted cells, when exposed to 80 mM acetic acid for 200 min ...

  5. Oxidative stress is involved in heat-induced cell death in Saccharomyces cerevisiae.

    OpenAIRE

    Davidson, J. F.; Whyte, B.; Bissinger, P H; Schiestl, R H

    1996-01-01

    The cause for death after lethal heat shock is not well understood. A shift from low to intermediate temperature causes the induction of heat-shock proteins in most organisms. However, except for HSP104, a convincing involvement of heat-shock proteins in the development of stress resistance has not been established in Saccharomyces cerevisiae. This paper shows that oxidative stress and antioxidant enzymes play a major role in heat-induced cell death in yeast. Mutants deleted for the antioxida...

  6. Synthesis of hepatitis B virus surface protein derivates in yeast S. cerevisiae

    OpenAIRE

    Bulavaitė, Aistė; Sabaliauskaitė, Rasa; Staniulis, Juozas; Sasnauskas, Kęstutis

    2006-01-01

    HBV surface proteins PreS1[13–59]-S, PreS1[20–59]-S, PreS1[30–59]-S, PreS1[40–59]-S, PreS1[50–59]-S, PreS1[90–119]-S were produced in S.cerevisiae and purified. Electron microscopy suggested spherical virus-like particle formation for all the proteins except PreS1[90–119]-S. The PreS1[90–119] sequence was demonstrated to decrease protein solubility. Proteins are suitable for Tupaia primary hepatocyte binding investigations, diagnostic products and vaccine candidate development. Hepatito B ...

  7. [Construction of Saccharomyces cerevisiae cell factories for lycopene production].

    Science.gov (United States)

    Shi, Ming-Yu; Liu Yi; Wang, Dong; Lu, Fu-Ping; Huang, Lu-Qi; Dai, Zhu-Bo; Zhang, Xue-Li

    2014-10-01

    For microbial production of lycopene, the lycopene synthetic genes from Pantoea agglomerans were integrated into Saccharomyces cerevisiae strain BY4742, to obtain strain ZD-L-000 for production of 0.17 mg · L(-1) lycopene. Improving supplies of isoprenoid precursors was then investigated for increasing lycopene production. Four key genes were chosen to be overexpressed, inclu- ding truncated 3-hydroxy-3-methylglutaryl-CoA reductase gene (tHMG1), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, a mutated global regulatory factor gene (upc2.1), a fusion gene of FPP synthase (ERG20) and endogenous GGPP synthase (BTS1), which is a key enzyme in the diterpenoid synthetic pathway, and GGPP synthase gene (SaGGPS) from Sulfolobus acidocaldarius. Over-expression of upc2.1 could not improve lycopene production, while over-expression of tHMGI , BTS1-ERG20 and SaGGPS genes led to 2-, 16. 9- and20. 5-fold increase of lycopene production, respectively. In addition, three effective genes, tHMG1, BTS1-ERG20 and SaGGPS, were integrated into rDNA sites of ZD-L-000, resulting in strain ZD-L-201 for production of 13.23 mg · L(-1) lycopene, which was 77-fold higher than that of the parent strain. Finally, two-phase extractive fermentation was performed. The titer of lycopene increased 10-fold to 135.21 mg · L(-1). The engineered yeast strains obtained in this work provided the basis for fermentative production of lycopene. PMID:25751950

  8. SLA2 mutations cause SWE1-mediated cell cycle phenotypes in Candida albicans and Saccharomyces cerevisiae

    OpenAIRE

    Gale, Cheryl A.; Leonard, Michelle D.; Finley, Kenneth R.; Christensen, Leah; McClellan, Mark; Abbey, Darren; Kurischko, Cornelia; Bensen, Eric; Tzafrir, Iris; Kauffman, Sarah; Becker, Jeff; Berman, Judith

    2009-01-01

    The early endocytic patch protein Sla2 is important for morphogenesis and growth rates in Saccharomyces cerevisiae and Candida albicans, but the mechanism that connects these processes is not clear. Here we report that growth defects in cells lacking CaSLA2 or ScSLA2 are associated with a cell cycle delay that is influenced by Swe1, a morphogenesis checkpoint kinase. To establish how Swe1 monitors Sla2 function, we compared actin organization and cell cycle dynamics in strains lacking other c...

  9. Effect of Saccharomyces cerevisiae cells immobilisation on mead production

    OpenAIRE

    Pereira, A.P.; Ferreira, A. Mendes; Oliveira, J. M.; Estevinho, L .M.; Faia, A. Mendes

    2014-01-01

    Mead is a traditional alcoholic beverage obtained by the fermentation of diluted honey performed by yeasts. In this work the potential of application of immobilised yeast cells on single-layer Ca-alginate or double-layer alginateechitosan for mead production was assessed for the first time. The meads produced either with entrapped or free cells were evaluated in terms of quality and aroma profile. The immobilisation procedure had no adverse effect on cell viability, since minor differen...

  10. Intracellular pH distribution as a cell health indicator in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Aabo, Thomas; Glückstad, Jesper; Siegumfeldt, Henrik;

    2011-01-01

    Internal pH regulation is vital for many cell functions, including transport mechanisms and metabolic enzyme activity. More specifically, transport mechanisms are to a wide degree governed by internal pH distributions. We introduce the term standard deviation of the intracellular pH (s.......d.(pHint)) to describe the internal pH distributions. The cellular pH distributional response to external stress such as heat has not previously been determined. In this study, the intracellular pH (pHi) and the s.d.(pHint) of Saccharomyces cerevisiae cells exposed to supralethal temperatures were measured...

  11. Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

    OpenAIRE

    Levin, David E.

    2011-01-01

    The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to...

  12. Influence of α sex factor on the biosynthesis of the cell wall from Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Cells of Saccharomyces cerevisiae produce peptide hormones (a and α) which dramatically affect the physiology, structure, and behavior of cells from the opposite mating type, presumably in preparation for conjugation. Some cell division cycle mutants mimick several of the changes induced by α factor. Accordingly, conditional mutants cdc 28, cdc 36, cdc 37, and cdc 39 undergo arrest in G1, exhibit shmoo morphology and are able to mate when they are transferred to the restrictive temperature. Formation of shmoo cells would require increased synthesis of glycosyl transferases involved in the biosynthesis of cell wall polysaccharides. Accordingly, the authors investigated the effect of G1 arrest on the chemical composition of the cell wall and on the levels of glycosyl transferases. Arrest in G1 was obtained by two methods: addition of α factor, and transfer of a cdc 28 mutant to the restrictive temperature

  13. Nucleotide-excision repair of DNA in cell-free extracts of the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    A wide spectrum of DNA lesions are repaired by the nucleotide-excision repair (NER) pathway in both eukaryotic and prokaryotic cells. We have developed a cell-free system in Saccharomyces cerevisiae that supports NER. NER was monitored by measuring repair synthesis in DNA treated with cisplatin or with UV radiation. Repair synthesis in vitro was defective in extracts of rad1, rad2, and rad10 mutant cells, all of which have mutations in genes whose products are known to be required for NER in vivo. Additionally, repair synthesis was complemented by mixing different mutant extracts, or by adding purified Rad1 or Rad10 protein to rad1 or rad10 mutant extracts, respectively. The latter observation demonstrates that the Rad1 and Rad10 proteins directly participate in the biochemical pathway of NER. NER supported by nuclear extracts requires ATP and Mg2+ and is stimulated by polyethylene glycol and by small amounts of whole cell extract containing overexpressed Rad2 protein. The nuclear extracts also contain base-excision repair activity that is present at wild-type levels in rad mutant extracts. This cell-free system is expected to facilitate studies on the biochemical pathway of NER in S. cerevisiae

  14. Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

    DEFF Research Database (Denmark)

    Weiss Nielsen, Martin; Sternberg, Claus; Molin, Søren;

    2011-01-01

    Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological properties compared to free living microorganisms. Biofilms in nature are often difficult to investigate and reside under poorly defined conditions(1). ...

  15. Design and Optimization of a Process for Sugarcane Molasses Fermentation by Saccharomyces cerevisiae Using Response Surface Methodology

    OpenAIRE

    Nour Sh. El-Gendy; Madian, Hekmat R.; Abu Amr, Salem S.

    2013-01-01

    A statistical model was developed in this study to describe bioethanol production through a batch fermentation process of sugarcane molasses by locally isolated Saccharomyces cerevisiae Y-39. Response surface methodology RSM based on central composite face centered design CCFD was employed to statistically evaluate and optimize the conditions for maximum bioethanol production and study the significance and interaction of incubation period, initial pH, incubation temperature, and molasses conc...

  16. Increasing ethanol productivity during xylose fermentation by cell recycling of recombinant Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Roca, Christophe Francois Aime; Olsson, Lisbeth

    2003-01-01

    The influence of cell recycling of xylose-fermenting Saccharomyces cerevisiae TMB3001 was investigated during continuous cultivation on a xylose-glucose mixture. By using cell recycling at the dilution rate (D) of 0.05 h(-1), the cell-mass concentration could be increased from 2.2 g l(-1) to 22 g...... ethanol productivity was in the range of 0.23-0.26 g g(-1) h(-1) with or without cell recycling, showing that an increased cell-mass concentration did not influence the efficiency of the yeast.......(-1). Consequently, the volumetric ethanol productivity increased ten-fold, from 0.5 g l(-1) h(-1) to 5.35 g l(-1) h(-1). By increasing the biomass concentration, the xylose consumption rate increased from 0.75 g xylose l(-1) h(-1) without recycling to 1.9 g l(-1) h(-1) with recycling. The specific...

  17. Ectopic Expression of Arabidopsis Phospholipase A Genes Elucidates Role of Phospholipase Bs in S. cerevisiae Cells

    OpenAIRE

    Zhang, Meng; Zhang, Yan; Giblin, E Michael; Taylor, David C.

    2009-01-01

    In S. cerevisiae neither disruption of the phospholipase B triple knockout mutant (plb1plb2plb3; plb123) nor over-expression of phospholipase Bs (PLBs) result in a phenotype different from wild type. In performing experiments to characterize candidate plant phospholipase (PLA) genes, we found, surprisingly, that ectopic expression of either of two different A. thaliana PLA2 or PLA1 genes in the yeast plb123 mutant completely inhibited cell growth. We proposed that while PLBs might not be esse...

  18. The final cut: cell polarity meets cytokinesis at the bud neck in S. cerevisiae.

    Science.gov (United States)

    Juanes, Maria Angeles; Piatti, Simonetta

    2016-08-01

    Cell division is a fundamental but complex process that gives rise to two daughter cells. It includes an ordered set of events, altogether called "the cell cycle", that culminate with cytokinesis, the final stage of mitosis leading to the physical separation of the two daughter cells. Symmetric cell division equally partitions cellular components between the two daughter cells, which are therefore identical to one another and often share the same fate. In many cases, however, cell division is asymmetrical and generates two daughter cells that differ in specific protein inheritance, cell size, or developmental potential. The budding yeast Saccharomyces cerevisiae has proven to be an excellent system to investigate the molecular mechanisms governing asymmetric cell division and cytokinesis. Budding yeast is highly polarized during the cell cycle and divides asymmetrically, producing two cells with distinct sizes and fates. Many components of the machinery establishing cell polarization during budding are relocalized to the division site (i.e., the bud neck) for cytokinesis. In this review we recapitulate how budding yeast cells undergo polarized processes at the bud neck for cell division. PMID:27085703

  19. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    which apoptosis can be studied using the novel, temperature sensitive mutant, cdc77. The cdc77 cells are defective in a G1 process, and die show the characteristc signs of apoptosis: condensation of the chromatin, degradation of the inner nuclear membrane, dilation of the space between the nuclear...... membranes, condensation of the cytoplasm and degradation of DNA to 50kb fragmensts. It should be noted that in yeast, in contrast to higher eukaryotes, the nuclear membrane remain intact and the chromosomes remain uncondensed and invisible during mitosis. The cdc77 mutant exhibit a defect in initiation of...

  20. Ethanol fermentation of molasses by Saccharomyces cerevisiae cells immobilized onto sugar beet pulp

    Directory of Open Access Journals (Sweden)

    Vučurović Vesna M.

    2012-01-01

    Full Text Available Natural adhesion of Saccharomyces cerevisiae onto sugar beet pulp (SBP is a very simple and cheap immobilization method for retaining high cells density in the ethanol fermentation system. In the present study, yeast cells were immobilized by adhesion onto SBP suspended in the synthetic culture media under different conditions such as: glucose concentration (100, 120 and 150 g/l, inoculum concentration (5, 10 and 15 g/l dry mass and temperature (25, 30, 35 and 40°C. In order to estimate the optimal immobilization conditions the yeast cells retention (R, after each immobilization experiment was analyzed. The highest R value of 0.486 g dry mass yeast /g dry mass SBP was obtained at 30°C, glucose concentration of 150 g/l, and inoculum concentration of 15 g/l. The yeast immobilized under these conditions was used for ethanol fermentation of sugar beet molasses containing 150.2 g/l of reducing sugar. Efficient ethanol fermentation (ethanol concentration of 70.57 g/l, fermentation efficiency 93.98% of sugar beet molasses was achieved using S. cerevisiae immobilized by natural adhesion on SBP. [Projekat Ministarstva nauke Republike Srbije, br. TR-31002

  1. On-line cell mass monitoring of Saccharomyces cerevisiae cultivations by multi-wavelength fluorescence

    DEFF Research Database (Denmark)

    Haack, Martin Brian; Eliasson, Anna; Olsson, Lisbeth

    2004-01-01

    decomposition of the multivariate fluorescent landscape, whereby underlying spectra of the individual intrinsic fluorophors present in the cell mass were estimated. Furthermore, gravimetrically determined cell mass concentration was used together with the fluorescence spectra for calibration and validation of......The catalyst in bioprocesses, i.e. the cell mass, is one of the most challenging and important variables to monitor in bioprocesses. In the present study, cell mass in cultivations with Saccharomyces cerevisiae was monitored on-line with a non-invasive in situ placed sensor measuring multi......-wavelength culture fluorescence. The excitation wavelength ranged from 270 to 550 nm with 20 nm steps and the emission wavelength range was from 310 to 590 nm also with 20 nm steps. The obtained spectra were analysed chemometrically with the multi-way technique, parallel factor analysis (PARAFAC), resulting in a...

  2. Production of proteinase A by Saccharomyces cerevisiae in a cell-recycling fermentation system: Experiments and computer simulations

    DEFF Research Database (Denmark)

    Grøn, S.; Biedermann, K.; Emborg, Claus

    1996-01-01

    Overproduction of proteinase A by recombinant Saccharomyces cerevisiae was investigated by cultivations in a cell-recycling bioreactor. Membrane filtration was used to separate cells from the broth. Recycling ratios and dilution rates were varied and the effect on enzyme production was studied both...

  3. AMIODARONE INDUCES THE SYNTHESIS OF HSPS IN SACCHAROMYCES CEREVISIAE AND ARABIDOPSIS THALIANA CELLS

    Directory of Open Access Journals (Sweden)

    Pyatrikas D.V.

    2012-08-01

    Full Text Available Many biotic and abiotic stresses cause an increase of cytosolic Ca2+ level in cells. Calcium is one of the most important second messengers, regulating many various activities in the cell and was known to affect expression of stress activated genes. Mild heat shock induces the expression of heat shock proteins (Hsps which protect cell from drastic heat shock exposure. There are some literature data permitting to suggest that transient elevation of cytosolic Ca2+ level in plant cells is important for activation of Hsps expression. On the other hand mitochondria are known to regulate the intracellular calcium and reactive oxygen species signaling. It has been shown recently that mild heat shock induces hyperpolarization of inner mitochondrial membrane in plant and yeast cells and this event is critically important for activation of Hsps expression. To reveal the relationship between mitochondrial activity, intracellular calcium homeostasis and Hsps expression an antiarrhythmic drug amiodarone (AMD have been used. AMD is known to cause transient increase of cytosolic Ca2+ level in Saccharomyces cerevisiae. Obtained results have showed that AMD treatment induced the synthesis of Hsp104p in S. cerevisiae cells and Hsp101p in A. thaliana cell culture. Induction of Hsp104p synthesis leads to enhanced yeast capability to survive lethal heat shock exposure. Development of S. cerevisiae thermotolerance depended significantly on the presence of Hsp104p. Elevation of Hsp104p level in the result of AMD treatment was shown to be governed by activity of Msn2p and Msn4p transcription factors. Deletion of the MSN2 and MSN4 genes abrogated the AMD ability to induce Hsp104p synthesis. Mild heat shock and AMD treatment induced the hyperpolarization of the inner mitochondrial membrane in yeast and Arabidopsis cells which accompanied by HSP synthesis and development of thermotolerance. It was suggested that increase of cytosolic Ca2+ level after AMD treatment

  4. [Cloning and expression of bacteriophage FMV lysocyme gene in cells of yeasts Saccharomyces cerevisiae and Pichia pastoris].

    Science.gov (United States)

    Kozlov, D G; Cheperigin, S E; Chestkov, A V; Krylov, V N; Tsygankov, Iu D

    2010-03-01

    Cloning, sequencing, and expression of the gene for soluble lysozyme of bacteriophage FMV from Gram-negative Pseudomonas aeruginosa bacteria were conducted in yeast cells. Comparable efficiency of two lysozyme expression variants (as intracellular or secreted proteins) was estimated in cells of Saccharomyces cerevisiae and Pichia pastoris. Under laboratory conditions, yeast S. cerevisiae proved to be more effective producer of phage lysozyme than P. pastoris, the yield of the enzyme in the secreted form being significantly higher than that produced in the intracellular form. PMID:20391778

  5. Industrial systems biology of Saccharomyces cerevisiae enables novel succinic acid cell factory.

    Directory of Open Access Journals (Sweden)

    José Manuel Otero

    Full Text Available Saccharomyces cerevisiae is the most well characterized eukaryote, the preferred microbial cell factory for the largest industrial biotechnology product (bioethanol, and a robust commerically compatible scaffold to be exploitted for diverse chemical production. Succinic acid is a highly sought after added-value chemical for which there is no native pre-disposition for production and accmulation in S. cerevisiae. The genome-scale metabolic network reconstruction of S. cerevisiae enabled in silico gene deletion predictions using an evolutionary programming method to couple biomass and succinate production. Glycine and serine, both essential amino acids required for biomass formation, are formed from both glycolytic and TCA cycle intermediates. Succinate formation results from the isocitrate lyase catalyzed conversion of isocitrate, and from the α-keto-glutarate dehydrogenase catalyzed conversion of α-keto-glutarate. Succinate is subsequently depleted by the succinate dehydrogenase complex. The metabolic engineering strategy identified included deletion of the primary succinate consuming reaction, Sdh3p, and interruption of glycolysis derived serine by deletion of 3-phosphoglycerate dehydrogenase, Ser3p/Ser33p. Pursuing these targets, a multi-gene deletion strain was constructed, and directed evolution with selection used to identify a succinate producing mutant. Physiological characterization coupled with integrated data analysis of transcriptome data in the metabolically engineered strain were used to identify 2(nd-round metabolic engineering targets. The resulting strain represents a 30-fold improvement in succinate titer, and a 43-fold improvement in succinate yield on biomass, with only a 2.8-fold decrease in the specific growth rate compared to the reference strain. Intuitive genetic targets for either over-expression or interruption of succinate producing or consuming pathways, respectively, do not lead to increased succinate. Rather, we

  6. In vivo robustness analysis of cell division cycle genes in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Hisao Moriya

    2006-07-01

    Full Text Available Intracellular biochemical parameters, such as the expression level of gene products, are considered to be optimized so that a biological system, including the parameters, works effectively. Those parameters should have some permissible range so that the systems have robustness against perturbations, such as noise in gene expression. However, little is known about the permissible range in real cells because there has been no experimental technique to test it. In this study, we developed a genetic screening method, named "genetic tug-of-war" (gTOW that evaluates upper limit copy numbers of genes in a model eukaryote Saccharomyces cerevisiae, and we applied it for 30 cell-cycle related genes (CDC genes. The experiment provided unique quantitative data that could be used to argue the system-level properties of the cell cycle such as robustness and fragility. The data were used to evaluate the current computational model, and refinements to the model were suggested.

  7. Saccharomyces Cerevisiae Cell Wall Components as Tools for Ochratoxin A Decontamination

    Directory of Open Access Journals (Sweden)

    Małgorzata Piotrowska

    2015-04-01

    Full Text Available The aim of this study was to evaluate the usefulness of Saccharomyces cerevisiae cell wall preparations in the adsorption of ochratoxin A (OTA. The study involved the use of a brewer’s yeast cell wall devoid of protein substances, glucans obtained by water and alkaline extraction, a glucan commercially available as a dietary supplement for animals and, additionally, dried brewer’s yeast for comparison. Fourier Transform Infrared (FTIR analysis of the obtained preparations showed bands characteristic for glucans in the resulting spectra. The yeast cell wall preparation, water-extracted glucan and the commercial glucan bound the highest amount of ochratoxin A, above 55% of the initial concentration, and the alkaline-extracted glucan adsorbed the lowest amount of this toxin. It has been shown that adsorption is most effective at a close-to-neutral pH, while being considerably limited in alkaline conditions.

  8. Characterization of Pneumocystis Major Surface Glycoprotein Gene (msg) Promoter Activity in Saccharomyces cerevisiae

    OpenAIRE

    Kutty, Geetha; Shroff, Robert; Kovacs, Joseph A.

    2013-01-01

    Major surface glycoprotein (Msg), the most abundant cell surface protein of Pneumocystis, plays an important role in the interaction of this opportunistic pathogen with host cells, and its potential for antigenic variation may facilitate evasion of host immune responses. In the present study, we have identified and characterized the promoter region of msg in 3 species of Pneumocystis: P. carinii, P. jirovecii, and P. murina. Because Pneumocystis cannot be cultured, promoter activity was measu...

  9. Analysis of HIV-1 Vpr determinants responsible for cell growth arrest in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Yao Xiao-Jian

    2004-08-01

    Full Text Available Abstract Background The HIV-1 genome encodes a well-conserved accessory gene product, Vpr, that serves multiple functions in the retroviral life cycle, including the enhancement of viral replication in nondividing macrophages, the induction of G2 cell-cycle arrest, and the modulation of HIV-1-induced apoptosis. We previously reported the genetic selection of a panel of di-tryptophan (W-containing peptides capable of interacting with HIV-1 Vpr and inhibiting its cytostatic activity in Saccharomyces cerevisiae (Yao, X.-J., J. Lemay, N. Rougeau, M. Clément, S. Kurtz, P. Belhumeur, and E. A. Cohen, J. Biol. Chem. v. 277, p. 48816–48826, 2002. In this study, we performed a mutagenic analysis of Vpr to identify sequence and/or structural determinants implicated in the interaction with di-W-containing peptides and assessed the effect of mutations on Vpr-induced cytostatic activity in S. cerevisiae. Results Our data clearly shows that integrity of N-terminal α-helix I (17–33 and α-helix III (53–83 is crucial for Vpr interaction with di-W-containing peptides as well as for the protein-induced cytostatic effect in budding yeast. Interestingly, several Vpr mutants, mainly in the N- and C-terminal domains, which were previously reported to be defective for cell-cycle arrest or apoptosis in human cells, still displayed a cytostatic activity in S. cerevisiae and remained sensitive to the inhibitory effect of di-W-containing peptides. Conclusions Vpr-induced growth arrest in budding yeast can be effectively inhibited by GST-fused di-W peptide through a specific interaction of di-W peptide with Vpr functional domain, which includes α-helix I (17–33 and α-helix III (53–83. Furthermore, the mechanism(s underlying Vpr-induced cytostatic effect in budding yeast are likely to be distinct from those implicated in cell-cycle alteration and apoptosis in human cells.

  10. Surface cell immobilization within perfluoroalkoxy microchannels

    Science.gov (United States)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

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

    Science.gov (United States)

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

    2016-03-01

    The yeast cell wall of Saccharomyces cerevisiae is an important source of β-d-glucan, a glucose homopolymer with many functional, nutritional and human health benefits. In the present study, the yeast cell wall fractionation process involving enzymatic treatments (savinase and lipolase enzymes) affected most of the physical and functional characteristics of extracted fractions. Thus, the fractionation process showed that β-d-glucan fraction F4 had significantly higher swelling power and fat binding capacity compared to other fractions (F1, F2 and F3). It also exhibited a viscosity of 652.12mPas and a high degree of brightness of extracted β-d-glucan fraction. Moreover, the fractionation process seemed to have an effect on structural and thermal properties of extracted fractions. Overall, results showed that yeast β-d-glucan had good potential for use as a prebiotic ingredient in food, as well as medicinal and pharmaceutical products. PMID:26471666

  12. Ultraviolet-endonuclease activity in cell extracts of Saccharomyces cerevisiae mutants defective in excision of pyrimidine dimers

    International Nuclear Information System (INIS)

    Cell-free extracts of ultraviolet-sensitive mutants of Saccharomyces cerevisiae defective in excision of pyrimidine dimers, rad1, rad2, rad3, rad4, rad10, and rad16, as well as the extracts of the wild-type strain RAD+, display ultraviolet-endonuclease activity

  13. Reduction of volatile acidity of acidic wines by immobilized Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Vilela, A; Schuller, D; Mendes-Faia, A; Côrte-Real, M

    2013-06-01

    Excessive volatile acidity in wines is a major problem and is still prevalent because available solutions are nevertheless unsatisfactory, namely, blending the filter-sterilized acidic wine with other wines of lower volatile acidity or using reverse osmosis. We have previously explored the use of an empirical biological deacidification procedure to lower the acetic acid content of wines. This winemaker's enological practice, which consists in refermentation associated with acetic acid consumption by yeasts, is performed by mixing the acidic wine with freshly crushed grapes, musts, or marc from a finished wine fermentation. We have shown that the commercial strain Saccharomyces cerevisiae S26 is able to decrease the volatile acidity of acidic wines with a volatile acidity higher than 1.44 g L(-1) acetic acid, with no detrimental impact on wine aroma. In this study, we aimed to optimize the immobilization of S26 cells in alginate beads for the bioreduction of volatile acidity of acidic wines. We found that S26 cells immobilized in double-layer alginate-chitosan beads could reduce the volatile acidity of an acidic wine (1.1 g L(-1) acetic acid, 12.5 % (v/v) ethanol, pH 3.12) by 28 and 62 % within 72 and 168 h, respectively, associated with a slight decrease in ethanol concentration (0.7 %). Similar volatile acidity removal efficiencies were obtained in medium with high glucose concentration (20 % w/v), indicating that this process may also be useful in the deacidification of grape musts. We, therefore, show that immobilized S. cerevisiae S26 cells in double-layer beads are an efficient alternative to improve the quality of wines with excessive volatile acidity. PMID:23361840

  14. Anethole induces apoptotic cell death accompanied by reactive oxygen species production and DNA fragmentation in Aspergillus fumigatus and Saccharomyces cerevisiae.

    Science.gov (United States)

    Fujita, Ken-Ichi; Tatsumi, Miki; Ogita, Akira; Kubo, Isao; Tanaka, Toshio

    2014-02-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum, and antimicrobial activity that is weaker than that of other antibiotics on the market. When combined with polygodial, nagilactone E, and n-dodecanol, anethole has been shown to possess significant synergistic antifungal activity against a budding yeast, Saccharomyces cerevisiae, and a human opportunistic pathogenic yeast, Candida albicans. However, the antifungal mechanism of anethole has not been completely determined. We found that anethole stimulated cell death of a human opportunistic pathogenic fungus, Aspergillus fumigatus, in addition to S. cerevisiae. The anethole-induced cell death was accompanied by reactive oxygen species production, metacaspase activation, and DNA fragmentation. Several mutants of S. cerevisiae, in which genes related to the apoptosis-initiating execution signals from mitochondria were deleted, were resistant to anethole. These results suggest that anethole-induced cell death could be explained by oxidative stress-dependent apoptosis via typical mitochondrial death cascades in fungi, including A. fumigatus and S. cerevisiae. PMID:24393541

  15. Use of Saccharomyces cerevisiae cells immobilized on orange peel as biocatalyst for alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Plessas, S.; Bekatorou, A; Koutinas, A.A.; Soupioni, M. [University of Patras (Greece). Department of Chemistry, Food Biotechnology Group; Banat, I.M.; Marchant, R. [University of Ulster, Coleraine, N. Ireland (United Kingdom). School of Biomedical Sciences

    2007-03-15

    A biocatalyst was prepared by immobilizing a commercial Saccharomyces cerevisiae strain (baker's yeast) on orange peel pieces for use in alcoholic fermentation and for fermented food applications. Cell immobilization was shown by electron microscopy and by the efficiency of the immobilized biocatalyst for alcoholic fermentation of various carbohydrate substrates (glucose, molasses, raisin extracts) and at various temperatures (30-15 {sup o}C). Fermentation times in all cases were low (5-15 h) and ethanol productivities were high (av. 150.6 g/ld) showing good operational stability of the biocatalyst and suitability for commercial applications. Reasonable amounts of volatile by-products were produced at all temperatures studied, revealing potential application of the proposed biocatalyst in fermented food applications, to improve productivities and quality. (author)

  16. Industrial Systems Biology of Saccharomyces cerevisiae Enables Novel Succinic Acid Cell Factory

    DEFF Research Database (Denmark)

    Otero, José Manuel; Cimini, Donatella; Patil, Kiran Raosaheb;

    2013-01-01

    Saccharomyces cerevisiae is the most well characterized eukaryote, the preferred microbial cell factory for the largest industrial biotechnology product (bioethanol), and a robust commerically compatible scaffold to be exploitted for diverse chemical production. Succinic acid is a highly sought...... production. Glycine and serine, both essential amino acids required for biomass formation, are formed from both glycolytic and TCA cycle intermediates. Succinate formation results from the isocitrate lyase catalyzed conversion of isocitrate, and from the α-keto-glutarate dehydrogenase catalyzed conversion of...... genetic targets for either over-expression or interruption of succinate producing or consuming pathways, respectively, do not lead to increased succinate. Rather, we demonstrate how systems biology tools coupled with directed evolution and selection allows non-intuitive, rapid and substantial re...

  17. N-hypermannose glycosylation disruption enhances recombinant protein production by regulating secretory pathway and cell wall integrity in Saccharomyces cerevisiae.

    Science.gov (United States)

    Tang, Hongting; Wang, Shenghuan; Wang, Jiajing; Song, Meihui; Xu, Mengyang; Zhang, Mengying; Shen, Yu; Hou, Jin; Bao, Xiaoming

    2016-01-01

    Saccharomyces cerevisiae is a robust host for heterologous protein expression. The efficient expression of cellulases in S. cerevisiae is important for the consolidated bioprocess that directly converts lignocellulose into valuable products. However, heterologous proteins are often N-hyperglycosylated in S. cerevisiae, which may affect protein activity. In this study, the expression of three heterologous proteins, β-glucosidase, endoglucanase and cellobiohydrolase, was found to be N-hyperglycosylated in S. cerevisiae. To block the formation of hypermannose glycan, these proteins were expressed in strains with deletions in key Golgi mannosyltransferases (Och1p, Mnn9p and Mnn1p), respectively. Their extracellular activities improved markedly in the OCH1 and MNN9 deletion strains. Interestingly, truncation of the N-hypermannose glycan did not increase the specific activity of these proteins, but improved the secretion yield. Further analysis showed OCH1 and MNN9 deletion up-regulated genes in the secretory pathway, such as protein folding and vesicular trafficking, but did not induce the unfolded protein response. The cell wall integrity was also affected by OCH1 and MNN9 deletion, which contributed to the release of secretory protein extracellularly. This study demonstrated that mannosyltransferases disruption improved protein secretion through up-regulating secretory pathway and affecting cell wall integrity and provided new insights into glycosylation engineering for protein secretion. PMID:27156860

  18. Changes of telomere length cause reciprocal changes in the lifespan of mother cells in Saccharomyces cerevisiae

    OpenAIRE

    Austriaco, Nicanor R.; Guarente, Leonard P.

    1997-01-01

    Budding yeast cells divide asymmetrically, giving rise to a mother and its daughter. Mother cells have a limited division potential, called their lifespan, which ends in proliferation-arrest and lysis. In this report we mutate telomerase in Saccharomyces cerevisiae to shorten telomeres and show that, rather than shortening lifespan, this leads to a significant extension in lifespan. This extension requires the product of the SIR3 gene, an essential component of the silencing machinery which b...

  19. 31P NMR studies of intracellular pH and phosphate metabolism during cell division cycle of Saccharomyces cerevisiae.

    OpenAIRE

    Gillies, R.J.; Ugurbil, K; den Hollander, J A; Shulman, R G

    1981-01-01

    We have analyzed changes in intracellular pH and phosphate metabolism during the cell cycle of Saccharomyces cerevisiae (NCYC 239) by using high-resolution 31P NMR spectroscopy. High-density yeast cultures (2 x 10(8) cells per ml) were arrested prior to "start" by sequential glucose deprivation, after which they synchronously replicated DNA and divided after a final glucose feeding. Oxygenation of arrested cultures in the absence of glucose led to increased levels of sugar phosphates and ATP ...

  20. Glycoprotein Hypersecretion Alters the Cell Wall in Trichoderma reesei Strains Expressing the Saccharomyces cerevisiae Dolichylphosphate Mannose Synthase Gene▿

    OpenAIRE

    Perlińska-Lenart, Urszula; Orłowski, Jacek; Laudy, Agnieszka E.; Zdebska, Ewa; Palamarczyk, Grażyna; Kruszewska, Joanna S.

    2006-01-01

    Expression of the Saccharomyces cerevisiae DPM1 gene (coding for dolichylphosphate mannose synthase) in Trichoderma reesei (Hypocrea jecorina) increases the intensity of protein glycosylation and secretion and causes ultrastructural changes in the fungal cell wall. In the present work, we undertook further biochemical and morphological characterization of the DPM1-expressing T. reesei strains. We established that the carbohydrate composition of the fungal cell wall was altered with an increas...

  1. Surface cell immobilization within perfluoroalkoxy microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

  2. Yeast surface display of dehydrogenases in microbial fuel-cells.

    Science.gov (United States)

    Gal, Idan; Schlesinger, Orr; Amir, Liron; Alfonta, Lital

    2016-12-01

    Two dehydrogenases, cellobiose dehydrogenase from Corynascus thermophilus and pyranose dehydrogenase from Agaricus meleagris, were displayed for the first time on the surface of Saccharomyces cerevisiae using the yeast surface display system. Surface displayed dehydrogenases were used in a microbial fuel cell and generated high power outputs. Surface displayed cellobiose dehydrogenase has demonstrated a midpoint potential of -28mV (vs. Ag/AgCl) at pH=6.5 and was used in a mediator-less anode compartment of a microbial fuel cell producing a power output of 3.3μWcm(-2) using lactose as fuel. Surface-displayed pyranose dehydrogenase was used in a microbial fuel cell and generated high power outputs using different substrates, the highest power output that was achieved was 3.9μWcm(-2) using d-xylose. These results demonstrate that surface displayed cellobiose dehydrogenase and pyranose dehydrogenase may successfully be used in microbial bioelectrochemical systems. PMID:27459246

  3. Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani, Farshid; Younesi, Habibollah; Esmaeili Sari, Abbas [Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, P.O. Box: 64414-356 (Iran); Najafpour, Ghasem [Department of Chemical Engineering, Faculty of Engineering, Noshirvani University of Technology, Babol (Iran)

    2011-02-15

    Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h{sup -1}) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y{sub E/S}), volumetric ethanol productivity (Q{sub P}) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l{sup -1} h{sup -1} and 96%, respectively. (author)

  4. Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

  5. Defects in Protein Folding Machinery Affect Cell Wall Integrity and Reduce Ethanol Tolerance in S. cerevisiae.

    Science.gov (United States)

    Narayanan, Aswathy; Pullepu, Dileep; Reddy, Praveen Kumar; Uddin, Wasim; Kabir, M Anaul

    2016-07-01

    The chaperonin complex CCT/TRiC (chaperonin containing TCP-1/TCP-1 ring complex) participates in the folding of many crucial proteins including actin and tubulin in eukaryotes. Mutations in genes encoding its subunits can affect protein folding and in turn, the physiology of the organism. Stress response in Saccharomyces cerevisiae is important in fermentation reactions and operates through overexpression and underexpression of genes, thus altering the protein profile. Defective protein folding machinery can disturb this process. In this study, the response of cct mutants to stress conditions in general and ethanol in specific was investigated. CCT1 mutants showed decreased resistance to different conditions tested including osmotic stress, metal ions, surfactants, reducing and oxidising agents. Cct1-3 mutant with the mutation in the conserved ATP-binding region showed irreversible defects than other mutants. These mutants were found to have inherent cell wall defects and showed decreased ethanol tolerance. This study reveals that cell wall defects and ethanol sensitivity are linked. Genetic and proteomic analyses showed that the yeast genes RPS6A (ribosomal protein), SCL1 (proteasomal subunit) and TDH3 (glyceraldehyde-3-phosphate dehydrogenase) on overexpression, improved the growth of cct1-3 mutant on ethanol. We propose the breakdown of common stress response pathways caused by mutations in CCT complex and the resulting scarcity of functional stress-responsive proteins, affecting the cell's defence against different stress agents in cct mutants. Defective cytoskeleton and perturbed cell wall integrity reduce the ethanol tolerance in the mutants which are rescued by the extragenic suppressors. PMID:26992923

  6. Fermentation Temperature Modulates Phosphatidylethanolamine and Phosphatidylinositol Levels in the Cell Membrane of Saccharomyces cerevisiae

    OpenAIRE

    Henderson, Clark M.; Zeno, Wade F.; Lerno, Larry A.; Longo, Marjorie L; Block, David E.

    2013-01-01

    During alcoholic fermentation, Saccharomyces cerevisiae is exposed to a host of environmental and physiological stresses. Extremes of fermentation temperature have previously been demonstrated to induce fermentation arrest under growth conditions that would otherwise result in complete sugar utilization at “normal” temperatures and nutrient levels. Fermentations were carried out at 15°C, 25°C, and 35°C in a defined high-sugar medium using three Saccharomyces cerevisiae strains with diverse fe...

  7. Rapid Identification and Enumeration of Saccharomyces cerevisiae Cells in Wine by Real-Time PCR

    OpenAIRE

    Martorell, P.; Querol, A.; Fernández-Espinar, M. T.

    2005-01-01

    Despite the beneficial role of Saccharomyces cerevisiae in the food industry for food and beverage production, it is able to cause spoilage in wines. We have developed a real-time PCR method to directly detect and quantify this yeast species in wine samples to provide winemakers with a rapid and sensitive method to detect and prevent wine spoilage. Specific primers were designed for S. cerevisiae using the sequence information obtained from a cloned random amplified polymorphic DNA band that ...

  8. Cell surface recycling in yeast: mechanisms and machineries.

    Science.gov (United States)

    MacDonald, Chris; Piper, Robert C

    2016-04-15

    Sorting internalized proteins and lipids back to the cell surface controls the supply of molecules throughout the cell and regulates integral membrane protein activity at the surface. One central process in mammalian cells is the transit of cargo from endosomes back to the plasma membrane (PM) directly, along a route that bypasses retrograde movement to the Golgi. Despite recognition of this pathway for decades we are only beginning to understand the machinery controlling this overall process. The budding yeastSaccharomyces cerevisiae, a stalwart genetic system, has been routinely used to identify fundamental proteins and their modes of action in conserved trafficking pathways. However, the study of cell surface recycling from endosomes in yeast is hampered by difficulties that obscure visualization of the pathway. Here we briefly discuss how recycling is likely a more prevalent process in yeast than is widely appreciated and how tools might be built to better study the pathway. PMID:27068957

  9. Misregulation of Scm3p/HJURP causes chromosome instability in Saccharomyces cerevisiae and human cells.

    Directory of Open Access Journals (Sweden)

    Prashant K Mishra

    2011-09-01

    Full Text Available The kinetochore (centromeric DNA and associated proteins is a key determinant for high fidelity chromosome transmission. Evolutionarily conserved Scm3p is an essential component of centromeric chromatin and is required for assembly and function of kinetochores in humans, fission yeast, and budding yeast. Overexpression of HJURP, the mammalian homolog of budding yeast Scm3p, has been observed in lung and breast cancers and is associated with poor prognosis; however, the physiological relevance of these observations is not well understood. We overexpressed SCM3 and HJURP in Saccharomyces cerevisiae and HJURP in human cells and defined domains within Scm3p that mediate its chromosome loss phenotype. Our results showed that the overexpression of SCM3 (GALSCM3 or HJURP (GALHJURP caused chromosome loss in a wild-type yeast strain, and overexpression of HJURP led to mitotic defects in human cells. GALSCM3 resulted in reduced viability in kinetochore mutants, premature separation of sister chromatids, and reduction in Cse4p and histone H4 at centromeres. Overexpression of CSE4 or histone H4 suppressed chromosome loss and restored levels of Cse4p at centromeres in GALSCM3 strains. Using mutant alleles of scm3, we identified a domain in the N-terminus of Scm3p that mediates its interaction with CEN DNA and determined that the chromosome loss phenotype of GALSCM3 is due to centromeric association of Scm3p devoid of Cse4p/H4. Furthermore, we determined that similar to other systems the centromeric association of Scm3p is cell cycle regulated. Our results show that altered stoichiometry of Scm3p/HJURP, Cse4p, and histone H4 lead to defects in chromosome segregation. We conclude that stringent regulation of HJURP and SCM3 expression are critical for genome stability.

  10. Cyclin-Dependent Kinase Co-Ordinates Carbohydrate Metabolism and Cell Cycle in S. cerevisiae.

    Science.gov (United States)

    Zhao, Gang; Chen, Yuping; Carey, Lucas; Futcher, Bruce

    2016-05-19

    Cyclin-dependent kinases (CDKs) control cell division in eukaryotes by phosphorylating proteins involved in division. But successful proliferation requires co-ordination between division and cellular growth in mass. Previous proteomic studies suggested that metabolic proteins, as well as cell division proteins, could potentially be substrates of cyclin-dependent kinases. Here we focus on two metabolic enzymes of the yeast S. cerevisiae, neutral trehalase (Nth1) and glycogen phosphorylase (Gph1), and show that their activities are likely directly controlled by CDK activity, thus allowing co-ordinate regulation of carbohydrate metabolism with cell division processes. In this case, co-ordinate regulation may optimize the decision to undertake a final cell division as nutrients are being exhausted. Co-regulation of cell division processes and metabolic processes by CDK activity may be a general phenomenon important for co-ordinating the cell cycle with growth. PMID:27203179

  11. The steady-state level and stability of TLS polymerase eta are cell cycle dependent in the yeast S. cerevisiae.

    Science.gov (United States)

    Plachta, Michal; Halas, Agnieszka; McIntyre, Justyna; Sledziewska-Gojska, Ewa

    2015-05-01

    Polymerase eta (Pol eta) is a ubiquitous translesion DNA polymerase that is capable of bypassing UV-induced pyrimidine dimers in an error-free manner. However, this specialized polymerase is error prone when synthesizing through an undamaged DNA template. In Saccharomyces cerevisiae, both depletion and overproduction of Pol eta result in mutator phenotypes. Therefore, regulation of the cellular abundance of this enzyme is of particular interest. However, based on the investigation of variously tagged forms of Pol eta, mutually contradictory conclusions have been reached regarding the stability of this polymerase in yeast. Here, we optimized a protocol for the detection of untagged yeast Pol eta and established that the half-life of the native enzyme is 80 ± 14 min in asynchronously growing cultures. Experiments with synchronized cells indicated that the cellular abundance of this translesion polymerase changes throughout the cell cycle. Accordingly, we show that the stability of Pol eta, but not its mRNA level, is cell cycle stage dependent. The half-life of the polymerase is more than fourfold shorter in G1-arrested cells than in those at G2/M. Our results, in concert with previous data for Rev1, indicate that cell cycle regulation is a general property of Y family TLS polymerases in S. cerevisiae. PMID:25766643

  12. Surface functionalization of chitosan-coated magnetic nanoparticles for covalent immobilization of yeast alcohol dehydrogenase from Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    A novel and efficient immobilization of yeast alcohol dehydrogenase (YADH, EC1.1.1.1) from Saccharomyces cerevisiae has been developed by using the surface functionalization of chitosan-coated magnetic nanoparticles (Fe3O4/KCTS) as support. The magnetic Fe3O4/KCTS nanoparticles were prepared by binding chitosan alpha-ketoglutaric acid (KCTS) onto the surface of magnetic Fe3O4 nanoparticles. Later, covalent immobilization of YADH was attempted onto the Fe3O4/KCTS nanoparticles. The effect of various preparation conditions on the immobilized YADH process such as immobilization time, enzyme concentration and pH was investigated. The influence of pH and temperature on the activity of the free and immobilized YADH using phenylglyoxylic acid as substrate has also been studied. The optimum reaction temperature and pH value for the enzymatic conversion catalyzed by the immobilized YADH were 30 oC and 7.4, respectively. Compared to the free enzyme, the immobilized YADH retained 65% of its original activity and exhibited significant thermal stability and good durability.

  13. Invert sugar formation with Saccharomyces cerevisiae cells encapsulated in magnetically responsive alginate microparticles

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Maděrová, Zdeňka; Šafaříková, Miroslava

    2009-01-01

    Roč. 321, - (2009), s. 1478-1481. ISSN 0304-8853 R&D Projects: GA MPO 2A-1TP1/094; GA MŠk(CZ) OC 157 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetic alginate microbeads * Saccharomyces cerevisiae * invertase Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.204, year: 2009

  14. Simultaneous Alcoholic and Malolactic Fermentations by Saccharomyces cerevisiae and Oenococcus oeni Cells Co-immobilized in Alginate Beads

    Science.gov (United States)

    Bleve, Gianluca; Tufariello, Maria; Vetrano, Cosimo; Mita, Giovanni; Grieco, Francesco

    2016-01-01

    Malolactic fermentation (MLF) usually takes place after the end of alcoholic fermentation (AF). However, the inoculation of lactic acid bacteria together with yeast starter cultures is a promising system to enhance the quality and safety of wine. In recent years, the use of immobilized cell systems has been investigated, with interesting results, for the production of different fermented foods and beverages. In this study we have carried out the simultaneous immobilization of Saccharomyces cerevisiae and Oenococcus oeni in alginate beads and used them in microvinifications tests to produce Negroamaro wine. The process was monitored by chemical and sensorial analyses and dominance of starters and cell leaking from beads were also checked. Co-immobilization of S. cerevisiae and O. oeni allowed to perform an efficient fermentation process, producing low volatile acidity levels and ethanol and glycerol concentrations comparable with those obtained by cell sequential inoculum and co-inoculum of yeast and bacteria cells in free form. More importantly, co-immobilization strategy produced a significant decrease of the time requested to complete AF and MLF. The immobilized cells could be efficiently reused for the wine fermentation at least three times without any apparent loss of cell metabolic activities. This integrated biocatalytic system is able to perform simultaneously AF and MLF, producing wines similar in organoleptic traits in comparison with wines fermented following traditional sequential AF and MLF with free cell starters. The immobilized-cell system, that we here describe for the first time in our knowledge, offers many advantages over conventional free cell fermentations, including: (i) elimination of non-productive cell growth phases; (ii) feasibility of continuous processing; (iii) re-use of the biocatalyst. PMID:27379072

  15. Critical analysis of data concerning Saccharomyces cerevisiae free-cell proliferations and fermentations assisted by magnetic and electromagnetic fields

    CERN Document Server

    Hristov, Jordan

    2011-01-01

    The review analyses studies on magnetically assisted proliferations and batch fermentations with Saccharomyces cerevisiae yeasts. The results available in the literature are contradictory and show two tendencies: magnetic field suppression of the cell growth and positive effects in batch fermentation with increasing both biomass and metabolite production. The amount of data analyzed allows several concepts existing in the literature to be outlined and critically commented. Further, a new concept of magnetically induced micro-dynamos, recently conceived, is developed towards a unified explanation of the results provided by proliferation and batch fermentation experiments

  16. Cell walls of Saccharomyces cerevisiae differentially modulated innate immunity and glucose metabolism during late systemic inflammation.

    Directory of Open Access Journals (Sweden)

    Bushansingh Baurhoo

    Full Text Available BACKGROUND: Salmonella causes acute systemic inflammation by using its virulence factors to invade the intestinal epithelium. But, prolonged inflammation may provoke severe body catabolism and immunological diseases. Salmonella has become more life-threatening due to emergence of multiple-antibiotic resistant strains. Mannose-rich oligosaccharides (MOS from cells walls of Saccharomyces cerevisiae have shown to bind mannose-specific lectin of Gram-negative bacteria including Salmonella, and prevent their adherence to intestinal epithelial cells. However, whether MOS may potentially mitigate systemic inflammation is not investigated yet. Moreover, molecular events underlying innate immune responses and metabolic activities during late inflammation, in presence or absence of MOS, are unknown. METHODS AND PRINCIPAL FINDINGS: Using a Salmonella LPS-induced systemic inflammation chicken model and microarray analysis, we investigated the effects of MOS and virginiamycin (VIRG, a sub-therapeutic antibiotic on innate immunity and glucose metabolism during late inflammation. Here, we demonstrate that MOS and VIRG modulated innate immunity and metabolic genes differently. Innate immune responses were principally mediated by intestinal IL-3, but not TNF-α, IL-1 or IL-6, whereas glucose mobilization occurred through intestinal gluconeogenesis only. MOS inherently induced IL-3 expression in control hosts. Consequent to LPS challenge, IL-3 induction in VIRG hosts but not differentially expressed in MOS hosts revealed that MOS counteracted LPS's detrimental inflammatory effects. Metabolic pathways are built to elucidate the mechanisms by which VIRG host's higher energy requirements were met: including gene up-regulations for intestinal gluconeogenesis (PEPCK and liver glycolysis (ENO2, and intriguingly liver fatty acid synthesis through ATP citrate synthase (CS down-regulation and ATP citrate lyase (ACLY and malic enzyme (ME up-regulations. However, MOS host

  17. Genomic, genetic and physiological effects of bio-electrospraying on live cells of the model yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The ability to directly engineer living cells is rapidly becoming a hot field of research for a wide range of applications within the life sciences. 'Bio-electrospraying' cells, a recently developed technique, has great potential in this area. In this paper, we quantify genetic, genomic and physiological effects of bio-electrospraying cells of a model eukaryote, the yeast Saccharomyces cerevisiae. Our results demonstrate that yeast cells bio-electrosprayed at 30 kV have not incurred any detectable damage at a genomic or genetic level, and that the detectable physiological stress of the procedure is negligible. These results support our proposal to use yeast as a model system to develop bio-electrospray devices and protocols

  18. Combining Magnetic Sorting of Mother Cells and Fluctuation Tests to Analyze Genome Instability During Mitotic Cell Aging in Saccharomyces cerevisiae

    OpenAIRE

    Patterson, Melissa N.; Maxwell, Patrick H.

    2014-01-01

    Saccharomyces cerevisiae has been an excellent model system for examining mechanisms and consequences of genome instability. Information gained from this yeast model is relevant to many organisms, including humans, since DNA repair and DNA damage response factors are well conserved across diverse species. However, S. cerevisiae has not yet been used to fully address whether the rate of accumulating mutations changes with increasing replicative (mitotic) age due to technical constraints. For i...

  19. Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth; Gro Rejkjær Sørensen, Laura; Weiss Nielsen, Martin; Lisby, Michael; Folkesson, Sven Anders; Regenberg, Birgitte

    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...

  20. Crambescidin-816 Acts as a Fungicidal with More Potency than Crambescidin-800 and -830, Inducing Cell Cycle Arrest, Increased Cell Size and Apoptosis in Saccharomyces cerevisiae

    OpenAIRE

    Vega, Félix V.; Vieytes, Mercedes R.; Botana, Luis M; Thomas, Olivier P.; Henar López-Alonso; Rubiolo, Juan A.; Eva Ternon

    2013-01-01

    In this paper, we show the effect of crambescidin-816, -800, and -830 on Saccharomyces cerevisiae viability. We determined that, of the three molecules tested, crambescidin-816 was the most potent. Based on this result, we continued by determining the effect of crambescidin-816 on the cell cycle of this yeast. The compound induced cell cycle arrest in G2/M followed by an increase in cell DNA content and size. When the type of cell death was analyzed, we observed that crambescidin-816 induced ...

  1. Checkpoints Studies Using the Budding Yeast Saccharomyces cerevisiae: Analysis of changes in protein level and subcellular localization during cell cycle progression

    OpenAIRE

    Wu, Xiaorong; Liu, Lili; HUANG, Mingxia

    2011-01-01

    Methods are described here to monitor changes in protein level and subcellular localization during the cell cycle progression in the budding yeast S. cerevisiae. Cell synchronization is achieved by an α-factor mediated block-and-release protocol. Cells are collected at different time points for the first two cell cycles upon release. Cellular DNA contents are analyzed by flow cytometry. Trichloroacetic acid protein precipitates are prepared for monitoring levels of cell cycle regulated protei...

  2. Expression of the hepatitis B surface antigen gene containing the preS2 region in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Yoshida,Iwao

    1991-02-01

    Full Text Available We constructed a plasmid, pBH103-ME5, in which the region encoding the 10 preS2 amino acid residues and the S domain of the hepatitis B surface antigen (HBsAg were regulated by the promoter of the yeast repressible acid phosphatase gene. Saccharomyces cerevisiae carrying pBH103-ME5 produced the HBs antigen (yHBsAg, when it was cultured in a medium containing a low concentration of phosphate. The antigen was purified to homogeneity. Its molecular weight was determined by Western blotting to be 24,000, and its amino acid composition agreed well with that deduced from the nucleotide sequence. The C-terminal amino acid sequence of yHBsAg was exactly the same as that predicted from the nucleotide sequence, while the N-terminal amino acid acetylserine, which was followed by 8 amino acid residues coded by the preS2 region. These results indicate that the recombinant yeast produced a single polypeptide consisting of the preS2 region and the subsequent S domain after being processed at the N-terminus

  3. Adaptation of a flocculent Saccharomyces cerevisiae strain to lignocellulosic inhibitors by cell recycle batch fermentation

    OpenAIRE

    Landaeta, R.; Aroca, G.; Acevedo, F.; J. A. Teixeira; Mussatto, Solange I.

    2013-01-01

    The ethanol production from lignocellulosic feedstocks is considered a promising strategy to increase global production of biofuels without impacting food supplies. However, some compounds released during the hydrolysis of lignocellulosic materials are toxic for the microbial metabolism, causing low ethanol yield and productivity during the fermentation. As an attempt to overcome this problem, the present study evaluated the adaptation of a flocculent strain of Saccharomyces cerevisiae (NRRL ...

  4. High-cell-density fermentation of Saccharomyces cerevisiae for the optimisation of mead production

    OpenAIRE

    Pereira, Ana Paula; Mendes-Ferreira, Alexandra; de Oliveira, José M.; Leticia M. Estevinho; Mendes-Faia, Arlete

    2013-01-01

    Mead is a traditional drink that contains 8 % and 18 % (v/v) of ethanol, resulting from the alcoholic fermentation of diluted honey by yeasts. Mead fermentation is a time-consuming process and the quality of the final product is highly variable. Therefore, the present investigation had two main objectives: first, to determine the adequate inoculum size of two commercial wine-making strains of Saccharomyces cerevisiae for the optimisation of mead fermentation; and second, to determine if an in...

  5. Cellular and mitochondrial respiration of Saccharomyces cerevisiae cells of different age

    Czech Academy of Sciences Publication Activity Database

    Hlousková, J.; Volejníková, A.; Sigler, Karel; Pichová, Alena

    Smolenice : Springer, 2009, s. 92-92. ISSN 1336-4839. [Annual Conference on Yeasts /37./. Smolenice (SK), 13.05.2009-15.05.2009] R&D Projects: GA ČR GA301/07/0339; GA MŠk 1M0570; GA MŠk ME 938 Institutional research plan: CEZ:AV0Z50200510 Keywords : Saccharomyces cerevisiae Subject RIV: EE - Microbiology, Virology

  6. BIOSORPTION OF TERNARY CADMIUM, NICKEL AND COBALT IONS FROM AQUEOUS SOLUTION ONTO SACCHAROMYCES CEREVISIAE CELLS: BATCH AND COLUMN STUDIES

    Directory of Open Access Journals (Sweden)

    Maedeh Galedar

    2013-01-01

    Full Text Available The aim of this study was to remove cadmium, nickel and cobalt ions from aqueous solutions using yeast, Saccharomyces cerevisiae, pre-treated with ethanol. The cells are immobilized using polysulfone in both batch and continuous systems. To optimize the adsorption capacity of the yeast biomass, a batch system was used to investigate the effects of initial pH, initial biomass dose and initial metal ion concentration. Optimum conditions were obtained at pH 8 with a biomass of and ion concentrations of 8 and 100 mg L-1, respectively. Under these conditions, the maximum uptake capacity was 3.1 mg g-1 for cadmium, 1.2 mg g-1 for nickel and 0.68 mg g-1 for cobalt. To estimate the biomass uptake capacity of the ethanol pretreated S. cerevisiae, the isothermal Langmuir model was found to be a better fit with a correlation coefficient of R2 -1, bead column height of 25 cm and the input flow rate of 1 mL min-1. The calculated uptake capacity of the metal ions was 3.74 mg g-1 for cadmium, 1.57 mg g-1 for nickel and 1.56 mg g-1 for cobalt. The Thomas model (0.95242<0.9957 was shown to be more consistent compared with the test results. Polysulfone immobilization of yeast was found to increase removal by 48% compared to non-immobilized ethanol pr-treated yeast.

  7. Sensitive determination of L-lysine with a new amperometric microbial biosensor based on Saccharomyces cerevisiae yeast cells.

    Science.gov (United States)

    Akyilmaz, Erol; Erdoğan, Ali; Oztürk, Ramazan; Yaşa, Ihsan

    2007-01-15

    A new amperometric microbial biosensor based on Saccharomyces cerevisiae NRRL-12632 cells, which had been induced for lysine oxidase enzyme and immobilized in gelatin by a cross-linking agent was developed for the sensitive determination of L-lysine amino acid. To construct the microbial biosensor S. cerevisiae cells were activated and cultured in a suitable culture medium. By using gelatine (8.43 mg cm(-2)) and glutaraldehyde (0.25%), cells obtained in the logarithmic phase of the growth curve at the end of a 14 h period were immobilized and fixed on a pretreated oxygen sensitive Teflon membrane of a dissolved oxygen probe. The assay procedure of the microbial biosensor is based on the determination of the differences of the respiration activity of the cells on the oxygenmeter in the absence and the presence of L-lysine. According to the end point measurement technique used in the experiments it was determined that the microbial biosensor response depended linearly on L-lysine concentrations between 1.0 and 10.0 microM with a 1 min response time. In optimization studies of the microbial biosensor, the most suitable microorganism quantities were found to be 0.97x10(5)CFU cm(-2). In addition phosphate buffer (pH 7.5; 50 mM) and 30 degrees C were obtained as the optimum working conditions. In characterization studies of the microbial biosensor some parameters such as substrate specificity, interference effects of some substances on the microbial biosensor responses, reproducibility of the biosensor and operational and storage stability were investigated. PMID:16759846

  8. Radio protective effects of calcium channel blockers (Deltiazem) on survival of Saccharomyces cerevisiae cells irradiated with different doses of gamma rays

    International Nuclear Information System (INIS)

    Investigations of radioprotective effects of Deltiazem (as one of the commonly used calcium channel blockers, which is used in the treatment of acute and chronic angina and spasmo angina, in addition to the treatment of different types of essential hypertension) has been carried on Saccharomyces Cerevisiae cells. Cells cultures of the most famous yeast Saccharomyces Cerevisiae (bakers yeast) were irradiated with different doses of gamma rays. Results revealed that the necessary dose of gamma rays that leads to 10% of survived cellular population (D10 value) was about 256 Gy. This irradiation dose was used then in all irradiation experiments on culture of S. Cerevisiae cells in which different concentrations of Deltiazem (55, 110, 165 mg/Kg medium) were added before and after irradiation in order to study the radio protective effect of Deltiazem. Results showed that Deltiazem enhances survival percentage of irradiated S. Cerevisiae cultures in a concentration dependent manner. This study confirmed our previous works, which had demonstrated that Deltiazem protects lethally and supralethally irradiated rats, and enhances survival of pre-irradiated Deltiazem treated animals.(author)

  9. Chemical modulation of the ultra-weak photon emission from Saccharomyces cerevisiae and differentiated HL-60 cells

    Science.gov (United States)

    Červinková, Kateřina; Nerudová, Michaela; Hašek, Jiří; Cifra, Michal

    2015-01-01

    The ultra-weak photon emission (UPE) is a universal phenomenon common to all cells with active oxidative metabolism. Generally accepted mechanism of the origin of the ultra-weak photon emission considers reactions of radical or nonradical reactive oxygen species (ROS) with biomolecules such as lipids and proteins which lead to the formation of electron excited species. During the transition to the ground state the excess energy is released as a photon with a wavelength in the visible range of the electromagnetic spectrum. Since the intensity of the light is very low it is possible to be measured only by highly sensitive devices. We used Hamamatsu Photonics PMT module H7360-01 mounted into a light-tight chamber for the purposes of this work. The goal of our research is to delineate an origin of UPE from two model organisms; differentiated HL-60 cells (human promyelocytic leukemia) and yeast cells Saccharomyces cerevisiae. While the UPE from the yeast cells arises spontaneously during the growth without any external stimuli, UPE from HL-60 is induced by phorbol 12-myristate, 13-acetate (PMA). It is possible to modulate the UPE production by certain antioxidants which scavenge ROS formed during the metabolism (yeast cells) or respiratory burst (HL-60 cells). The experiments are focused on the description of effects caused by antioxidants. Several kinds of antioxidants (ascorbic acid, mannitol, glutathione) with different concentration were used and we studied the changes in the UPE intensities of and the temporal developments of the optical signal.

  10. Ethanol production from mahula (Madhuca latifolia L.) flowers with immobilized cells of Saccharomyces cerevisiae in Luffa cylindrica L. sponge discs

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Shuvashish; Mohanty, Rama Chandra [Department of Botany, Utkal University, Vanivihar, Bhubaneswar 751 004, Orissa (India); Ray, Ramesh Chandra [Microbiology Laboratory, Central Tuber Crops Research Institute (Regional Centre), Bhubaneswar 751 019, Orissa (India)

    2011-01-15

    The dried spongy fruit of luffa (Luffa cylindrica L.), a cucurbitaceous crop available in abundance in tropical and sub-tropical countries has been found to be a promising material for immobilizing microbial cells. The aim of the present study was to examine the ethanol production from mahula flowers in submerged fermentation using whole cells of Saccharomyces cerevisiae immobilized in luffa sponge discs. The cells not only survived but also were physiologically active in three more cycles of fermentation without significant reduction (<5%) in ethanol production. After 96 h, there was 91.1% sugar conversion producing 223.2 g ethanol/kg flowers (1st cycle) which was 0.99%, 2.3% and 3.2% more than 2nd (221 g ethanol/kg flowers), 3rd (218 g ethanol/kg flowers) and 4th (216 g ethanol/kg flowers) cycle of fermentation, respectively. Furthermore, ethanol production by immobilized cells was 8.96% higher than the free cells. (author)

  11. Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae.

    Science.gov (United States)

    Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, Helena; Arneborg, Nils

    2015-07-01

    The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides. PMID:26109361

  12. The Plant Cell Surface

    Institute of Scientific and Technical Information of China (English)

    Anne-Mie C.Emons; Kurt V.Fagerstedt

    2010-01-01

    @@ Multicellular organization and tissue construction has evolved along essentially different lines in plants and animals. Since plants do not run away, but are anchored in the soil, their tissues are more or less firm and stiff. This strength stems from the cell walls, which encase the fragile cytoplasm, and protect it.

  13. Protective effect of acetic acid against ethanol-induced cell death in "Saccharomyces cerevisiae"

    OpenAIRE

    Afonso, Andreia Fernandes

    2011-01-01

    O etanol é um produto final bem conhecido da fermentação alcoólica realizada por Saccharomyces cerevisiae. Em altas concentrações, é responsável pela redução de viabilidade celular e inibição da fermentação. Além disso, durante a fermentação alguns ácidos fracos, como os ácidos acético, butírico e pirúvico, produzidos pelo metabolismo da levedura, podem acumular-se no meio de crescimento e aumentar a toxicidade do etanol, o que resulta numa maior inibição de crescimento e fermentação (Gibson,...

  14. Improving L-arabinose utilization of pentose fermenting Saccharomyces cerevisiae cells by heterologous expression of L-arabinose transporting sugar transporters

    Directory of Open Access Journals (Sweden)

    Boles Eckhard

    2011-10-01

    Full Text Available Abstract Background Hydrolysates of plant biomass used for the production of lignocellulosic biofuels typically contain sugar mixtures consisting mainly of D-glucose and D-xylose, and minor amounts of L-arabinose. The yeast Saccharomyces cerevisiae is the preferred microorganism for the fermentative production of ethanol but is not able to ferment pentose sugars. Although D-xylose and L-arabinose fermenting S. cerevisiae strains have been constructed recently, pentose uptake is still a limiting step in mixed sugar fermentations. Results Here we described the cloning and characterization of two sugar transporters, AraT from the yeast Scheffersomyces stipitis and Stp2 from the plant Arabidopsis thaliana, which mediate the uptake of L-arabinose but not of D-glucose into S. cerevisiae cells. A yeast strain lacking all of its endogenous hexose transporter genes and expressing a bacterial L-arabinose utilization pathway could no longer take up and grow with L-arabinose as the only carbon source. Expression of the heterologous transporters supported uptake and utilization of L-arabinose especially at low L-arabinose concentrations but did not, or only very weakly, support D-glucose uptake and utilization. In contrast, the S. cerevisiae D-galactose transporter, Gal2, mediated uptake of both L-arabinose and D-glucose, especially at high concentrations. Conclusions Using a newly developed screening system we have identified two heterologous sugar transporters from a yeast and a plant which can support uptake and utilization of L-arabinose in L-arabinose fermenting S. cerevisiae cells, especially at low L-arabinose concentrations.

  15. The cell-surface interaction.

    Science.gov (United States)

    Hayes, J S; Czekanska, E M; Richards, R G

    2012-01-01

    The realm of surface-dependent cell and tissue responses is the foundation of orthopaedic-device-related research. However, to design materials that elicit specific responses from tissues is a complex proposition mainly because the vast majority of the biological principles controlling the interaction of cells with implants remain largely ambiguous. Nevertheless, many surface properties, such as chemistry and topography, can be manipulated in an effort to selectively control the cell-material interaction. On the basis of this information there has been much research in this area, including studies focusing on the structure and composition of the implant interface, optimization of biological and chemical coatings and elucidation of the mechanisms involved in the subsequent cell-material interactions. Although a wealth of information has emerged, it also advocates the complexity and dynamism of the cell-material interaction. Therefore, this chapter aims to provide the reader with an introduction to the basic concepts of the cell-material interaction and to provide an insight into the factors involved in determining the cell and tissue response to specific surface features, with specific emphasis on surface microtopography. PMID:21984613

  16. 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.

  17. Yeast cell surface display for lipase whole cell catalyst and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun; Zhang, Rui; Lian, Zhongshuai; Wang, Shihui; Wright, Aaron T.

    2014-08-01

    The cell surface display technique allows for the expression of target proteins or peptides on the microbial cell surface by fusing an appropriate protein as an anchoring motif. Yeast display systems, such as Pichia pastoris, Yarowia lipolytica and Saccharomyces cerevisiae, are ideal, alternative and extensive display systems with the advantage of simple genetic manipulation and post-translational modification of expressed heterologous proteins. Engineered yeasts show high performance characteristics and variant utilizations. Herein, we comprehensively summarize the variant factors affecting lipase whole cell catalyst activity and display efficiency, including the structure and size of target proteins, screening anchor proteins, type and chain length of linkers, and the appropriate matching rules among the above-mentioned display units. Furthermore, we also address novel approaches to enhance stability and activity of recombinant lipases, such as VHb gene co-expression, multi-enzyme co-display technique, and the micro-environmental interference and self-assembly techniques. Finally, we represent the variety of applications of whole cell surface displayed lipases on yeast cells in non-aqueous phases, including synthesis of esters, PUFA enrichment, resolution of chiral drugs, organic synthesis and biofuels. We demonstrate that the lipase surface display technique is a powerful tool for functionalizing yeasts to serve as whole cell catalysts, and increasing interest is providing an impetus for broad application of this technique.

  18. Optical manipulation of Saccharomyces cerevisiae cells reveals that green light protection against UV irradiation is favored by low Ca2+ and requires intact UPR pathway.

    Science.gov (United States)

    Farcasanu, Ileana C; Mitrica, Radu; Cristache, Ligia; Nicolau, Ioana; Ruta, Lavinia L; Paslaru, Liliana; Comorosan, Sorin

    2013-11-01

    Optical manipulation of Saccharomyces cerevisiae cells with high density green photons conferred protection against the deleterious effects of UV radiation. Combining chemical screening with UV irradiation of yeast cells, it was noted that the high density green photons relied on the presence of intact unfolded protein response (UPR) pathway to exert their protective effect and that the low Ca(2+) conditions boosted the effect. UPR chemical inducers tunicamycin, dithiotreitol and calcium chelators augmented the green light effect in a synergic action against UV-induced damage. Photo-manipulation of cells was a critical factor since the maximum protection was achieved only when cells were pre-exposed to green light. PMID:24056073

  19. Pinostrobin from Boesenbergia pandurata is an inhibitor of Ca2+-signal-mediated cell-cycle regulation in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Wangkangwan, Wachirasak; Boonkerd, Saipin; Chavasiri, Warinthorn; Sukapirom, Kasama; Pattanapanyasat, Kovit; Kongkathip, Ngampong; Miyakawa, Tokichi; Yompakdee, Chulee

    2009-07-01

    Upon searching plant extracts for inhibitors of the Ca(2+) signaling pathway using the zds1Delta-yeast proliferation based assay, a crude rhizome extract of Boesenbergia pandurata was found to be strongly positive, and from this extract pinostrobin, alpinetin, and pinocembrin chalcone were isolated as active components. Further biochemical experiments confirmed that pinostrobin possesses inhibitory activity on the Ca(2+) signals involved in the control of G2/M phase cell cycle progression in Saccharomyces cerevisiae. PMID:19584530

  20. Proteomic Analyses Reveal that Sky1 Modulates Apoptosis and Mitophagy in Saccharomyces cerevisiae Cells Exposed to Cisplatin

    Directory of Open Access Journals (Sweden)

    Silvia Rodríguez-Lombardero

    2014-07-01

    Full Text Available Sky1 is the only member of the SR (Serine–Arginine protein kinase family in Saccharomyces cerevisiae. When yeast cells are treated with the anti-cancer drug cisplatin, Sky1 kinase activity is necessary to produce the cytotoxic effect. In this study, proteome changes in response to this drug and/or SKY1 deletion have been evaluated in order to understand the role of Sky1 in the response of yeast cells to cisplatin. Results reveal differential expression of proteins previously related to the oxidative stress response, DNA damage, apoptosis and mitophagy. With these precedents, the role of Sky1 in apoptosis, necrosis and mitophagy has been evaluated by flow-cytometry, fluorescence microscopy, biosensors and fluorescence techniques. After cisplatin treatment, an apoptotic-like process diminishes in the ∆sky1 strain in comparison to the wild-type. The treatment does not affect mitophagy in the wild-type strain, while an increase is observed in the ∆sky1 strain. The increased resistance to cisplatin observed in the ∆sky1 strain may be attributable to a decrease of apoptosis and an increase of mitophagy.

  1. Bioethanol Production from Uncooked Raw Starch by Immobilized Surface-engineered Yeast Cells

    Science.gov (United States)

    Chen, Jyh-Ping; Wu, Kuo-Wei; Fukuda, Hideki

    Surface-engineered yeast Saccharomyces cerevisiae codisplaying Rhizopus oryzae glucoamylase and Streptococcus bovis α-amylase on the cell surface was used for direct production of ethanol from uncooked raw starch. By using 50 g/L cells during batch fermentation, ethanol concentration could reach 53 g/L in 7 days. During repeated batch fermentation, the production of ethanol could be maintained for seven consecutive cycles. For cells immobilized in loofa sponge, the concentration of ethanol could reach 42 g/L in 3 days in a circulating packed-bed bioreactor. However, the production of ethanol stopped thereafter because of limited contact between cells and starch. The bioreactor could be operated for repeated batch production of ethanol, but ethanol concentration dropped to 55% of its initial value after five cycles because of a decrease in cell mass and cell viability in the bioreactor. Adding cells to the bioreactor could partially restore ethanol production to 75% of its initial value.

  2. High-cell-density fermentation of Saccharomyces cerevisiae for the optimisation of mead production.

    Science.gov (United States)

    Pereira, A P; Mendes-Ferreira, A; Oliveira, J M; Estevinho, L M; Mendes-Faia, A

    2013-02-01

    Mead is a traditional drink that contains 8%-18% (v/v) of ethanol, resulting from the alcoholic fermentation of diluted honey by yeasts. Mead fermentation is a time-consuming process and the quality of the final product is highly variable. Therefore, the present investigation had two main objectives: first, to determine the adequate inoculum size of two commercial wine-making strains of Saccharomyces cerevisiae for the optimisation of mead fermentation; and second, to determine if an increase in yeast pitching rates in batch fermentations altered the resulting aroma profiles. Minor differences were detected in the growth kinetics between the two strains at the lowest pitching rate. With increasing pitching rates net growth of the strain ICV D47 progressively decreased, whereas for the QA23 the increasing inoculum size had no influence on its net growth. The time required to reach the same stage of fermentation ranged from 24 to 96 h depending on the inoculum size. The final aroma composition was dependent on the yeast strain and inoculum size. Fourteen of the twenty-seven volatile compounds quantified could contribute to mead aroma and flavour because their concentrations rose above their respective thresholds. The formation of these compounds was particularly pronounced at low pitching rates, except in mead fermented by strain ICV D47, at 10(6) CFUs/mL. The esters isoamyl acetate, ethyl octanoate and ethyl hexanoate were the major powerful odourants found in the meads. The results obtained in this study demonstrate that yeast strain and inoculum size can favourably impact mead's flavour and aroma profiles. PMID:23122509

  3. Single cell synchrotron FT-IR microspectroscopy reveals a link between neutral lipid and storage carbohydrate fluxes in S. cerevisiae.

    Directory of Open Access Journals (Sweden)

    Frédéric Jamme

    Full Text Available In most organisms, storage lipids are packaged into specialized structures called lipid droplets. These contain a core of neutral lipids surrounded by a monolayer of phospholipids, and various proteins which vary depending on the species. Hydrophobic structural proteins stabilize the interface between the lipid core and aqueous cellular environment (perilipin family of proteins, apolipoproteins, oleosins. We developed a genetic approach using heterologous expression in Saccharomyces cerevisiae of the Arabidopsis thaliana lipid droplet oleosin and caleosin proteins AtOle1 and AtClo1. These transformed yeasts overaccumulate lipid droplets, leading to a specific increase in storage lipids. The phenotype of these cells was explored using synchrotron FT-IR microspectroscopy to investigate the dynamics of lipid storage and cellular carbon fluxes reflected as changes in spectral fingerprints. Multivariate statistical analysis of the data showed a clear effect on storage carbohydrates and more specifically, a decrease in glycogen in our modified strains. These observations were confirmed by biochemical quantification of the storage carbohydrates glycogen and trehalose. Our results demonstrate that neutral lipid and storage carbohydrate fluxes are tightly connected and co-regulated.

  4. High cell density culture with S. cerevisiae CEN.PK113-5D for IL-1β production: optimization, modeling, and physiological aspects.

    Science.gov (United States)

    Landi, Carmine; Paciello, Lucia; de Alteriis, Elisabetta; Brambilla, Luca; Parascandola, Palma

    2015-02-01

    Saccharomyces cerevisiae CEN.PK113-5D, a strain auxotrophic for uracil belonging to the CEN.PK family of the yeast S. cerevisiae, was cultured in aerated fed-batch reactor as such and once transformed to express human interleukin-1β (IL-1β), aiming at obtaining high cell densities and optimizing IL-1β production. Three different exponentially increasing glucose feeding profiles were tested, all of them "in theory" promoting respiratory metabolism to obtain high biomass/product yield. A non-structured non-segregated model was developed to describe the performance of S. cerevisiae CEN.PK113-5D during the fed-batch process and, in particular, its capability to metabolize simultaneously glucose and ethanol which derived from the precedent batch growth. Our study showed that the proliferative capacity of the yeast population declined along the fed-batch run, as shown by the exponentially decreasing specific growth rates on glucose. Further, a shift towards fermentative metabolism occurred. This shift took place earlier the higher was the feed rate and was more pronounced in the case of the recombinant strain. Determination of some physiological markers (acetate production, intracellular ROS accumulation, catalase activity and cell viability) showed that neither poor oxygenation nor oxidative stress was responsible for the decreased specific growth rate, nor for the shift to fermentative metabolism. PMID:25106469

  5. Metabolism of D-aminoacyl-tRNAs in Escherichia coli and Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Soutourina, J; Plateau, P; Blanquet, S

    2000-10-20

    In Escherichia coli, tyrosyl-tRNA synthetase is known to esterify tRNA(Tyr) with tyrosine. Resulting d-Tyr-tRNA(Tyr) can be hydrolyzed by a d-Tyr-tRNA(Tyr) deacylase. By monitoring E. coli growth in liquid medium, we systematically searched for other d-amino acids, the toxicity of which might be exacerbated by the inactivation of the gene encoding d-Tyr-tRNA(Tyr) deacylase. In addition to the already documented case of d-tyrosine, positive responses were obtained with d-tryptophan, d-aspartate, d-serine, and d-glutamine. In agreement with this observation, production of d-Asp-tRNA(Asp) and d-Trp-tRNA(Trp) by aspartyl-tRNA synthetase and tryptophanyl-tRNA synthetase, respectively, was established in vitro. Furthermore, the two d-aminoacylated tRNAs behaved as substrates of purified E. coli d-Tyr-tRNA(Tyr) deacylase. These results indicate that an unexpected high number of d-amino acids can impair the bacterium growth through the accumulation of d-aminoacyl-tRNA molecules and that d-Tyr-tRNA(Tyr) deacylase has a specificity broad enough to recycle any of these molecules. The same strategy of screening was applied using Saccharomyces cerevisiae, the tyrosyl-tRNA synthetase of which also produces d-Tyr-tRNA(Tyr), and which, like E. coli, possesses a d-Tyr-tRNA(Tyr) deacylase activity. In this case, inhibition of growth by the various 19 d-amino acids was followed on solid medium. Two isogenic strains containing or not the deacylase were compared. Toxic effects of d-tyrosine and d-leucine were reinforced upon deprivation of the deacylase. This observation suggests that, in yeast, at least two d-amino acids succeed in being transferred onto tRNAs and that, like in E. coli, the resulting two d-aminoacyl-tRNAs are substrates of a same d-aminoacyl-tRNA deacylase. PMID:10918062

  6. Whole-cell imaging of the budding yeast Saccharomyces cerevisiae by high-voltage scanning transmission electron tomography

    International Nuclear Information System (INIS)

    Electron tomography using a high-voltage electron microscope (HVEM) provides three-dimensional information about cellular components in sections thicker than 1 μm, although in bright-field mode image degradation caused by multiple inelastic scattering of transmitted electrons limit the attainable resolution. Scanning transmission electron microscopy (STEM) is believed to give enhanced contrast and resolution compared to conventional transmission electron microscopy (CTEM). Samples up to 1 μm in thickness have been analyzed with an intermediate-voltage electron microscope because inelastic scattering is not a critical limitation, and probe broadening can be minimized. Here, we employed STEM at 1 MeV high-voltage to extend the useful specimen thickness for electron tomography, which we demonstrate by a seamless tomographic reconstruction of a whole, budding Saccharomyces cerevisiae yeast cell, which is ∼3 μm in thickness. High-voltage STEM tomography, especially in the bright-field mode, demonstrated sufficiently enhanced contrast and intensity, compared to CTEM tomography, to permit segmentation of major organelles in the whole cell. STEM imaging also reduced specimen shrinkage during tilt-series acquisition. The fidelity of structural preservation was limited by cytoplasmic extraction, and the spatial resolution was limited by the relatively large convergence angle of the scanning probe. However, the new technique has potential to solve longstanding problems of image blurring in biological specimens beyond 1 μm in thickness, and may facilitate new research in cellular structural biology. - Highlights: • High voltage TEM and STEM tomography were compared to visualize whole yeast cells. • 1-MeV STEM-BF tomography had significant improvements in image contrast and SNR. • 1-MeV STEM tomography showed less specimen shrinkage than the TEM tomography. • KMnO4 post-treatment permitted segmenting the major cellular components

  7. Whole-cell imaging of the budding yeast Saccharomyces cerevisiae by high-voltage scanning transmission electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Kazuyoshi, E-mail: kazum@nips.ac.jp [National Institute for Physiological Sciences, Okazaki, Aichi 444-8585 (Japan); Esaki, Masatoshi; Ogura, Teru [Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811 (Japan); Arai, Shigeo; Yamamoto, Yuta; Tanaka, Nobuo [Ecotopia Science Institute, Nagoya University, Nagoya, Aichi 464-8603 (Japan)

    2014-11-15

    Electron tomography using a high-voltage electron microscope (HVEM) provides three-dimensional information about cellular components in sections thicker than 1 μm, although in bright-field mode image degradation caused by multiple inelastic scattering of transmitted electrons limit the attainable resolution. Scanning transmission electron microscopy (STEM) is believed to give enhanced contrast and resolution compared to conventional transmission electron microscopy (CTEM). Samples up to 1 μm in thickness have been analyzed with an intermediate-voltage electron microscope because inelastic scattering is not a critical limitation, and probe broadening can be minimized. Here, we employed STEM at 1 MeV high-voltage to extend the useful specimen thickness for electron tomography, which we demonstrate by a seamless tomographic reconstruction of a whole, budding Saccharomyces cerevisiae yeast cell, which is ∼3 μm in thickness. High-voltage STEM tomography, especially in the bright-field mode, demonstrated sufficiently enhanced contrast and intensity, compared to CTEM tomography, to permit segmentation of major organelles in the whole cell. STEM imaging also reduced specimen shrinkage during tilt-series acquisition. The fidelity of structural preservation was limited by cytoplasmic extraction, and the spatial resolution was limited by the relatively large convergence angle of the scanning probe. However, the new technique has potential to solve longstanding problems of image blurring in biological specimens beyond 1 μm in thickness, and may facilitate new research in cellular structural biology. - Highlights: • High voltage TEM and STEM tomography were compared to visualize whole yeast cells. • 1-MeV STEM-BF tomography had significant improvements in image contrast and SNR. • 1-MeV STEM tomography showed less specimen shrinkage than the TEM tomography. • KMnO{sub 4} post-treatment permitted segmenting the major cellular components.

  8. The cell wall and endoplasmic reticulum stress responses are coordinately regulated in Saccharomyces cerevisiae

    OpenAIRE

    Krysan, Damian J.

    2009-01-01

    The unfolded protein response (UPR) is an intracellular signaling pathway that regulates the cellular response to the accumulation of misfolded proteins in eukaryotes. Our group has demonstrated that cell wall stress activates UPR in yeast through signals transmitted by the cell wall integrity (CWI) mitogen-activated protein (MAP) kinase cascade. The UPR is required to maintain cell wall integrity; mutants lacking a functional UPR have defects in cell wall biosynthesis and are hypersensitive ...

  9. Live cell microscopy of DNA damage response in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Pinela da Silva, Sonia Cristina; Gallina, Irene; Eckert-Boulet, Nadine Valerie; Lisby, Michael

    Fluorescence microscopy of the DNA damage response in living cells stands out from many other DNA repair assays by its ability to monitor the response to individual DNA lesions in single cells. This is particularly true in yeast, where the frequency of spontaneous DNA lesions is relatively low...... live cell imaging allows for multiple cellular markers to be monitored over several hours. This chapter reviews useful fluorescent markers and genotoxic agents for studying the DNA damage response in living cells and provides protocols for live cell imaging, time-lapse microscopy, and for induction of...

  10. Cytoplasmic proteasomes are not indispensable for cell growth in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Hikaru; Arai, Naoko; Tanaka, Keiji, E-mail: tanaka-kj@igakuken.or.jp; Saeki, Yasushi, E-mail: saeki-ys@igakuken.or.jp

    2013-07-05

    Highlights: •We succeeded to control the proteasome localization by the anchor-away technique. •Nuclear proteasome-depleted cells showed a lethal phenotype. •Cytoplasmic proteasomes are not indispensable for cell growth in dividing cells. -- Abstract: The 26S proteasome is an essential protease complex responsible for the degradation of ubiquitinated proteins in eukaryotic cells. In rapidly proliferating yeast cells, proteasomes are mainly localized in the nucleus, but the biological significance of the proteasome localization is still unclear. In this study, we investigated the relationship between the proteasome localization and the functions by the anchor-away technique, a ligand-dependent sequestration of a target protein into specific compartment(s). Anchoring of the proteasome to the plasma membrane or the ribosome resulted in conditional depletion of the nuclear proteasomes, whereas anchoring to histone resulted in the proteasome sequestration into the nucleus. We observed that the accumulation of ubiquitinated proteins in all the proteasome-targeted cells, suggesting that both the nuclear and cytoplasmic proteasomes have proteolytic functions and that the ubiquitinated proteins are produced and degraded in each compartment. Consistent with previous studies, the nuclear proteasome-depleted cells exhibited a lethal phenotype. In contrast, the nuclear sequestration of the proteasome resulted only in a mild growth defect, suggesting that the cytoplasmic proteasomes are not basically indispensable for cell growth in rapidly growing yeast cells.

  11. Impacts of X-ray irradiation on Saccharomyces cerevisiae cells growth and physiological-biochemical characteristic

    Institute of Scientific and Technical Information of China (English)

    曹国珍; 张苗苗; 李文建; 缪建顺; 陆栋; 张文德

    2015-01-01

    In this paper, the growth curves of yeast cells exposed to X-rays were detected, and then fitted by Gompertz equation. The yeast cells treated with 50–125 Gy showed an increased exponential growth rate, and lower total biomass at plateau. At doses ≥ 150 Gy, cells showed a decreased exponential growth rate and higher total biomass at plateau. DNA lesions were detected by comet assay. Meanwhile, intracellular accumulation of reactive oxygen species (ROS), reduction of mitochondrial membrane potential (∆Ψm) and cell membrane integrity were evaluated. We conclude that X-ray irradiation results in DNA lesions, ROS accumulation and∆Ψm decline in a dose-dependent manner, and that these changes may be one of causes of X-rays-induced apoptosis in yeast. Furthermore, yeast cell membrane integrity appeared compromised following irradiation, suggesting that membrane damage may also have a role in the biological effects of radiation.

  12. Real-time viable-cell mass monitoring in high-cell-density fed-batch glutathione fermentation by Saccharomyces cerevisiae T65 in industrial complex medium.

    Science.gov (United States)

    Xiong, Zhi-Qiang; Guo, Mei-Jin; Guo, Yuan-Xin; Chu, Ju; Zhuang, Ying-Ping; Zhang, Si-Liang

    2008-04-01

    An on-line monitoring of viable-cell mass in high-cell-density fed-batch cultivations of Saccharomyces cerevisiae grown on an industrial complex medium was performed with an in situ capacitance probe fitted to a 50-l fermentor. Conventional off-line biomass determinations of several parameters, including dry cell weight (DCW), optical density at 600 nm wavelength (OD(600)), packed mycelial volume (PMV) and number of colony forming units (CFU), were performed throughout the bioprocess and then compared with on-line viable-cell concentrations measured using a capacitance probe. Capacitance versus viable biomass and all off-line biomass assay values were compared during glutathione fermentation in industrial complex culture media. As a result, the relationship between the number of colony forming units and capacitance with a correlation coefficient (R) of 0.995 was achieved. Simultaneously, compared with those determined by at-line indirect estimation methods including oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER), the specific growth rates estimated by on-line capacitance measurement could be more reliable during glutathione fermentation. Therefore, it is concluded that a capacitance probe is a practical tool for real-time viable biomass monitoring in high-cell-density fed-batch cultivation in a complex medium. PMID:18499059

  13. Two pathways of DNA double-strand break repair in G1 cells of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The G1 cells of the diploid yeast Saccharomyces cerevislae are known to be capable of a slow repair of DNA double-strand breaks (DSB) during holding the cells in a non-nutrient medium. In the present paper, it has been shown that S. cerevislae cells γ-irradiated in the G1 phase of cell cycle are capable of fast repair of DNA DSB; this process is completed within 30-40 min of holding the cells in water at 28 deg C. For this reason, the kinetics of DNA DSB repair during holding the cells in a non-nutrient medium are biphasic, i.e., the first, ''fast'' phase is completed within 30-40 min; wheras the second, ''slow'' one, within 48 h. Mutations rad51, rad52, rad54 and rad55 inhibit the fast repair of DNA DSB, whereas mutations rad50, rad53 and rad57 do not practically influence this process. It has been shown that the observed fast and slow repair of DNA DSB in the G1 diploid cells of S, cerevislae are separate pathways of DNA DSB repair in yeast

  14. Targeting population heterogeneity in Saccharomyces cerevisiae batch fermentation for optimal cell factories

    DEFF Research Database (Denmark)

    Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.; Carlqvist, Magnus; Sörensen, S.; Gernaey, Krist; Eliasson Lantz, Anna

    )). Significant gradients of e.g. dissolved oxygen, substrates, and pH are typically observed in many industrial scale fermentation processes. Consequently, the microbial cells experience rapid changes in environmental conditions as they circulate throughout the reactor, which might pose stress on the cells and...... constructed which enabled us to perform single cell level analysis, and thereby created the possibility to map population heterogeneity. A factorial design with pH, glucose concentration and oxygen level was performed in batch cultivations using the growth reporter strains to evaluate the effect of those...... environmental factors on heterogeneity level and amount of living cells. A highly dynamic behavior with regard to subpopulation distribution during the different growth stages was seen for the batch cultivations. Moreover, it could be demonstrated that the glucose concentration had a clear influence on the...

  15. The role of MAPK signalling pathways in acetic acid-induced cell death of Saccharomyces cerevisiae

    OpenAIRE

    Azevedo, Flávio Humberto Torres Dias Feio de

    2011-01-01

    Dissertação de mestrado em Genética Molecular Mitogenic Activated Protein Kinase (MAPK) cascades are important signalling pathways that allow yeast cells to swiftly adapt to changing environmental conditions. Previous studies suggested that the High Osmolarity Glycerol (HOG) MAPK pathway and ceramide production are involved in acetic-acid induced apoptosis in yeast. Evidence that changes in the levels of endogenous ceramides can affect yeast cell fate has also been put forth...

  16. Robustness and adaptation reveal plausible cell cycle controlling subnetwork in Saccharomyces cerevisiae.

    Science.gov (United States)

    Huang, Jiun-Yan; Huang, Chi-Wei; Kao, Kuo-Ching; Lai, Pik-Yin

    2013-04-10

    Biological systems are often organized spatially and temporally by multi-scale functional subsystems (modules). A specific subcellular process often corresponds to a subsystem composed of some of these interconnected modules. Accurate identification of system-level modularity organization from the large scale networks can provide valuable information on subsystem models of subcellular processes or physiological phenomena. Computational identification of functional modules from the large scale network is the key approach to solve the complexity of modularity in the past decade, but the overlapping and multi-scale nature of modules often renders unsatisfactory results in these methods. Most current methods for modularity detection are optimization-based and suffered from the drawback of size resolution limit. It is difficult to trace the origin of the unsatisfactory results, which may be due to poor data, inappropriate objective function selection or simply resulted from natural evolution, and hence no system-level accurate modular models for subcellular processes can be offered. Motivated by the idea of evolution with robustness and adaption as guiding principles, we propose a novel approach that can identify significant multi-scale overlapping modules that are sufficiently accurate at the system and subsystem levels, giving biological insights for subcellular processes. The success of our evolution strategy method is demonstrated by applying to the yeast protein-protein interaction network. Functional subsystems of important physiological phenomena can be revealed. In particular, the cell cycle controlling network is selected for detailed discussion. The cell cycle subcellular processes in yeast can be successfully dissected into functional modules of cell cycle control, cell size check point, spindle assembly checkpoint, and DNA damage check point in G2/M and S phases. The interconnections between check points and cell cycle control modules provide clues on the

  17. Correlation of cell growth and heterologous protein production by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Liu, Zihe; Hou, Jin; Martínez, José L.;

    2013-01-01

    With the increasing demand for biopharmaceutical proteins and industrial enzymes, it is necessary to optimize the production by microbial fermentation or cell cultures. Yeasts are well established for the production of a wide range of recombinant proteins, but there are also some limitations; e.g...

  18. Increasing cell biomass in Saccharomyces cerevisiae increases recombinant protein yield: the use of a respiratory strain as a microbial cell factory

    Directory of Open Access Journals (Sweden)

    Hedfalk Kristina

    2010-06-01

    Full Text Available Abstract Background Recombinant protein production is universally employed as a solution to obtain the milligram to gram quantities of a given protein required for applications as diverse as structural genomics and biopharmaceutical manufacture. Yeast is a well-established recombinant host cell for these purposes. In this study we wanted to investigate whether our respiratory Saccharomyces cerevisiae strain, TM6*, could be used to enhance the productivity of recombinant proteins over that obtained from corresponding wild type, respiro-fermentative strains when cultured under the same laboratory conditions. Results Here we demonstrate at least a doubling in productivity over wild-type strains for three recombinant membrane proteins and one recombinant soluble protein produced in TM6* cells. In all cases, this was attributed to the improved biomass properties of the strain. The yield profile across the growth curve was also more stable than in a wild-type strain, and was not further improved by lowering culture temperatures. This has the added benefit that improved yields can be attained rapidly at the yeast's optimal growth conditions. Importantly, improved productivity could not be reproduced in wild-type strains by culturing them under glucose fed-batch conditions: despite having achieved very similar biomass yields to those achieved by TM6* cultures, the total volumetric yields were not concomitantly increased. Furthermore, the productivity of TM6* was unaffected by growing cultures in the presence of ethanol. These findings support the unique properties of TM6* as a microbial cell factory. Conclusions The accumulation of biomass in yeast cell factories is not necessarily correlated with a proportional increase in the functional yield of the recombinant protein being produced. The respiratory S. cerevisiae strain reported here is therefore a useful addition to the matrix of production hosts currently available as its improved biomass

  19. Studies on the plasmid stability, plasmid copy number and endo(1, 3)(1, 4) b-glucanase production by free and alginate immobilised recombinant saccharomyces cerevisiae cells

    OpenAIRE

    Canavan, Peter D.

    1994-01-01

    A recombinant yeast strain, Saccharomyces cerevisiae DBY746, containing the plasmid pJG317, was grown in a variety of fermentation modes including batch, serial batch and chemostat culture incorporating a wide range of media types Plasmid pJG317 consists of a 2^-denved yeast episomal plasmid containing the gene which encodes for the bacterial enzyme endo (1,3)(1,4) P-glucanase. The concentration of enzyme produced appears to be proportional to the number of plasmid copies per cell. Specific e...

  20. Cell Surface Sensors: Lightning the Cellular Environment

    OpenAIRE

    Ali, Md Monsur; Kang, Dong-Ku; Tsang, Kyle; Fu, Moyu; Karp, Jeffrey M; Zhao, Weian

    2012-01-01

    Cell surface sensors are powerful tools to elucidate cell functions including cell signaling, metabolism and cell-to-cell communication. These sensors not only facilitate our understanding in basic biology but also advance the development of effective therapeutics and diagnostics. While genetically encoded fluorescent protein/peptide sensors have been most popular, emerging cell surface sensor systems including polymer-, nanoparticle-, and nucleic acid aptamer-based sensors have largely expan...

  1. 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)

    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

  2. Production of medium-chain volatile flavour esters in Pichia pastoris whole-cell biocatalysts with extracellular expression of Saccharomyces cerevisiae acyl-CoA: ethanol O-acyltransferase Eht1 or Eeb1

    DEFF Research Database (Denmark)

    Zhuang, Shiwen; Fu, Junshu; Powell, Chris; Huang, Jinhai; Xia, Yihe; Yan, Ruixiang

    2015-01-01

    catalyzed by acyl-CoA: ethanol O-acyltransferases Eht1 or Eeb1 in Saccharomyces cerevisiae. In this study, these two yeast enzymes were selected to explore their preparations as the form of whole cell biocatalysts for the production of volatile flavour esters. Here, the novel whole cell biocatalysts Pichia...

  3. High-cell-density fermentation for ergosterol production by Saccharomyces cerevisiae.

    Science.gov (United States)

    Shang, Fei; Wen, Shaohong; Wang, Xi; Tan, Tianwei

    2006-01-01

    The direct feedback control of glucose using an on-line ethanol concentration monitor for ergosterol production by high-cell-density fermentation was investigated and the fermentation parameters (e.g., pH, dissolved oxygen, ethanol concentration, oxygen uptake rate, carbon dioxide evolution rate and respiratory quotient) were analyzed. Controlling glucose feeding rate in accordance with ethanol concentration and adjusting pH with ammonia during the fermentation process were effective fed-batch methods for ergosterol production. The fermentation parameters well described the variation of the whole fermentation process. Cultivation in a 5 l fermentor was carried out under the following conditions: culture temperature, 30 degrees C; pH, 5.5; agitation speed, 600 rpm; fermentation time, 60 h; controlling ethanol concentration below 1% and keeping respiratory quotient (RQ) at approximately 1.0. Under these conditions, the yeast dry weight reached 120 g/l and the ergosterol yield reached 1500 mg/l. PMID:16503289

  4. Avaliação de compostos com atividade antioxidante em células da levedura Saccharomyces cerevisiae Evaluation of compounds with antioxidant activity in Saccharomyces cerevisiae yeast cells

    Directory of Open Access Journals (Sweden)

    Daniele Grazziotin Soares

    2005-03-01

    Full Text Available Antioxidantes são compostos que atuam inibindo e/ou diminuindo os efeitos desencadeados pelos radicais livres e compostos oxidantes. Diferentes métodos têm sido desenvolvidos para obter a diferenciação, seja qualitativa ou quantitativa, da capacidade antioxidante de compostos, tanto através de testes sem a utilização de células (testes químicos ou utilizando culturas celulares (testes biológicos. Os testes químicos são mais rápidos e simples de serem executados. No entanto, não são representativos das condições celulares do homem. Ensaios microbianos `in vivo' utilizando-se, principalmente, células eucarióticas da levedura Saccharomyces cerevisiae têm se mostrado muito adequados para determinação da capacidade antioxidante de diferentes compostos, fornecendo resultados rápidos, reprodutíveis e passíveis de serem correlacionados ao observado no homem. O objetivo deste trabalho foi avaliar a capacidade antioxidante do ácido L-ascórbico, vitamina E (alfa-tocoferol e dos flavonóides hesperidina, naringina, naringenina, quercetina, rutina e sakuranetina, utilizando como modelo de sistema biológico a levedura S. cerevisiae. Para realização dos testes, as células foram tratadas com o agente estressor apomorfina em presença e ausência das amostras. Os resultados mostraram que a rutina, hesperidina, sakuranetina, quercetina e naringina foram os compostos com maior atividade antioxidante, seguidos da naringenina e vitamina E. O ácido L-ascórbico e a mistura de ácido L-ascórbico e vitamina E não mostraram atividade antioxidante frente aos danos gerados pela apomorfina nas concentrações ensaiadas.Antioxidants are compounds that remove free-radicals or minimize their availability to generate oxidative stress. There are many methods to determine antioxidant capacity, but microbiological assays, using mainly eukaryotic cells, have shown similar results to man. The purpose of this work was to evaluate, through

  5. Cells behaviors and genotoxicity on topological surface

    Energy Technology Data Exchange (ETDEWEB)

    Yang, N.; Yang, M.K.; Bi, S.X. [Tianjin Key Laboratory of Fiber Modification and Functional Fiber, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin, 300387 (China); Chen, L., E-mail: chenlis@tjpu.edu.cn [Tianjin Key Laboratory of Fiber Modification and Functional Fiber, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin, 300387 (China); Zhu, Z.Y.; Gao, Y.T.; Du, Z. [Tianjin Key Laboratory of Artificial Cell, Tianjin Third Central Hospital, Tianjin, 300170 (China)

    2013-08-01

    To investigate different cells behaviors and genotoxicity, which were driven by specific microenvironments, three patterned surfaces (pillars, wide grooves and narrow grooves) and one smooth surface were prepared by template-based technique. Vinculin is a membrane-cytoskeletal protein in focal adhesion plaques and associates with cell–cell and cell–matrix junctions, which can promote cell adhesion and spreading. The immunofluorescence staining of vinculin revealed that the narrow grooves patterned substrate was favorable for L929 cell adhesion. For cell multiplication, the narrow grooves surface was fitted for the proliferation of L929, L02 and MSC cells, the pillars surface was only in favor of L929 cells to proliferate during 7 days of cell cultivation. Cell genetic toxicity was evaluated by cellular micronuclei test (MNT). The results indicated that topological surfaces were more suitable for L929 cells to proliferate and maintain the stability of genome. On the contrary, the narrow grooves surface induced higher micronuclei ratio of L02 and MSC cells than other surfaces. With the comprehensive results of cell multiplication and MNT, it was concluded that the wide grooves surface was best fitted for L02 cells to proliferate and have less DNA damages, and the smooth surface was optimum for the research of MSC cells in vitro. - Highlights: • Different cells behaviors on microstructure surfaces were discussed in this paper. • The expression of cell protein of Vinculin was studied in this research. • Cellular micronuclei test was applied to evaluate cells' genotoxicity. • Cell genotoxicity was first studied in the research field of topological surfaces.

  6. Cells behaviors and genotoxicity on topological surface

    International Nuclear Information System (INIS)

    To investigate different cells behaviors and genotoxicity, which were driven by specific microenvironments, three patterned surfaces (pillars, wide grooves and narrow grooves) and one smooth surface were prepared by template-based technique. Vinculin is a membrane-cytoskeletal protein in focal adhesion plaques and associates with cell–cell and cell–matrix junctions, which can promote cell adhesion and spreading. The immunofluorescence staining of vinculin revealed that the narrow grooves patterned substrate was favorable for L929 cell adhesion. For cell multiplication, the narrow grooves surface was fitted for the proliferation of L929, L02 and MSC cells, the pillars surface was only in favor of L929 cells to proliferate during 7 days of cell cultivation. Cell genetic toxicity was evaluated by cellular micronuclei test (MNT). The results indicated that topological surfaces were more suitable for L929 cells to proliferate and maintain the stability of genome. On the contrary, the narrow grooves surface induced higher micronuclei ratio of L02 and MSC cells than other surfaces. With the comprehensive results of cell multiplication and MNT, it was concluded that the wide grooves surface was best fitted for L02 cells to proliferate and have less DNA damages, and the smooth surface was optimum for the research of MSC cells in vitro. - Highlights: • Different cells behaviors on microstructure surfaces were discussed in this paper. • The expression of cell protein of Vinculin was studied in this research. • Cellular micronuclei test was applied to evaluate cells' genotoxicity. • Cell genotoxicity was first studied in the research field of topological surfaces

  7. TOTAL ANTIOXIDANT ACTIVITY OF YEAST SACCHAROMYCES CEREVISIAE

    OpenAIRE

    Blažena Lavová; Dana Urminská

    2013-01-01

    Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g. fats, lipids, proteins and DNA) from the damage of reactive oxygen species (ROS). Sacchamomyces cerevisiae are know as organisms with very important antioxidative enzyme systems such as superoxide dismutase or catalase. The total antioxidant activity (mmol Trolox equivalent – TE.g-1 d.w.) of Saccharomyces cerevisiae was measured by 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) during the yeas...

  8. Influence the oxidant action of selenium in radiosensitivity induction and cell death in yeast Saccharomyces cerevisiae; Influencia da acao oxidante do selenio na inducao da radiossensibilidade e morte celular na levedura Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Barbara Abranches de Araujo

    2012-07-01

    Ionizing radiations are from both natural sources such as from anthropogenic sources. Recently, radiotherapy has emerged as one of the most common therapies against cancer. Co-60 irradiators (cobalt-60 linear accelerators) are used to treat of malignant tumors routinely in hospitals around the world. Exposure to ionizing radiation can induce changes in cellular macromolecules and affect its functions, because they cause radiolysis of the water molecule generating reactive oxygen species, which can cause damage to virtually all organelles and cell components known as oxidative damage that can culminate in oxidative stress. Oxidative stress is a situation in which the balance between oxidants and antioxidants is broken resulting in excessive production of reactive species, it is not accompanied by the increase in antioxidant capacity, making it impossible to neutralize them. Selenium is a micronutrient considered as antioxidant, antiinflammatory, which could prevent cancer. Selenium in biological system exists as seleno proteins. Nowadays, 25 human seleno proteins have been identified, including glutathione peroxidase, an antioxidant enzyme. Yeasts have the ability to incorporate various metals such as iron, cadmium, zinc and selenium, as well as all biological organisms. The yeast Saccharomyces cerevisiae, unlike mammalian cells is devoid of seleno proteins, being considered as a practical model for studies on the toxicity of selenium, without any interference from the metabolism of seleno proteins. Moreover, yeast cells proliferate through the fermentation, the microbial equivalent of aerobic glycolysis in mammals and the process is also used by tumors. Several reports show that the pro-oxidante effects and induced toxic selenium compounds occur at lower doses and in malignant cells compared with benign cells. Therefore selenium giving a great therapeutic potential in cancer treatment .Our objective was to determine whether selenium is capable to sensitize yeasts

  9. The resistance of the yeast Saccharomyces cerevisiae to the biocide polyhexamethylene biguanide: involvement of cell wall integrity pathway and emerging role for YAP1

    Directory of Open Access Journals (Sweden)

    de Morais Marcos A

    2011-08-01

    Full Text Available Abstract Background Polyhexamethylene biguanide (PHMB is an antiseptic polymer that is mainly used for cleaning hospitals and pools and combating Acantamoeba infection. Its fungicide activity was recently shown by its lethal effect on yeasts that contaminate the industrial ethanol process, and on the PE-2 strain of Saccharomyces cerevisiae, one of the main fermenting yeasts in Brazil. This pointed to the need to know the molecular mechanism that lay behind the cell resistance to this compound. In this study, we examined the factors involved in PHMB-cell interaction and the mechanisms that respond to the damage caused by this interaction. To achieve this, two research strategies were employed: the expression of some genes by RT-qPCR and the analysis of mutant strains. Results Cell Wall integrity (CWI genes were induced in the PHMB-resistant Saccharomyces cerevisiae strain JP-1, although they are poorly expressed in the PHMB-sensitive Saccharomyces cerevisiae PE2 strain. This suggested that PHMB damages the glucan structure on the yeast cell wall. It was also confirmed by the observed sensitivity of the yeast deletion strains, Δslg1, Δrom2, Δmkk2, Δslt2, Δknr4, Δswi4 and Δswi4, which showed that the protein kinase C (PKC regulatory mechanism is involved in the response and resistance to PHMB. The sensitivity of the Δhog1 mutant was also observed. Furthermore, the cytotoxicity assay and gene expression analysis showed that the part played by YAP1 and CTT1 genes in cell resistance to PHMB is unrelated to oxidative stress response. Thus, we suggested that Yap1p can play a role in cell wall maintenance by controlling the expression of the CWI genes. Conclusion The PHMB treatment of the yeast cells activates the PKC1/Slt2 (CWI pathway. In addition, it is suggested that HOG1 and YAP1 can play a role in the regulation of CWI genes.

  10. The putative phosphoinositide-specific phospholipase C gene, PLC1, of the yeast Saccharomyces cerevisiae is important for cell growth.

    OpenAIRE

    Yoko-o, T; Matsui, Y; Yagisawa, H; Nojima, H; Uno, I; Toh-E, A

    1993-01-01

    Using the polymerase chain reaction technique, we have isolated a gene that encodes a putative phosphoinositide-specific phospholipase C (PLC) in the yeast Saccharomyces cerevisiae. The nucleotide sequence indicates that the gene encodes a polypeptide of 869 amino acid residues with a calculated molecular mass of 101 kDa. This polypeptide has both the X and Y regions conserved among mammalian PLC-beta, -gamma, and -delta, and the structure is most similar to that of mammalian PLC-delta. This ...

  11. Chemical modulation of the ultra-weak photon emission from Saccharomyces cerevisiae and differentiated HL-60 cells

    Czech Academy of Sciences Publication Activity Database

    Červinková, Kateřina; Nerudová, Michaela; Hašek, Jiří; Cifra, Michal

    Bellingham: SPIE, 2015, 94500P. ISBN 9781628415667. ISSN 0277-786X. [8th International Conference on Photonics, Devices, and System VI. Praha (CZ), 27.08.2014-29.08.2014] R&D Projects: GA ČR GA13-29294S Institutional support: RVO:67985882 ; RVO:61388971 Keywords : Saccharomyces cerevisiae * Ultra-weak photon emission * Photomultiplier tube Subject RIV: BO - Biophysics; EE - Microbiology, Virology (MBU-M)

  12. The ATX1 gene of Saccharomyces cerevisiae encodes a small metal homeostasis factor that protects cells against reactive oxygen toxicity.

    OpenAIRE

    Lin, S J; Culotta, V C

    1995-01-01

    In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as superoxide dismutase (SOD) and catalase. Here we describe the isolation and characterization of another gene in the yeast Saccharomyces cerevisiae that plays a critical role in detoxification of reactive oxygen species. This gene, named ATX1, was originally isolated by its ability to suppress oxygen toxicity in yeast lacking SOD. ATX1 encodes a 8.2-kDa poly...

  13. Cell recycling during repeated very high gravity bio-ethanol fermentations using the industrial Saccharomyces cerevisiae strain PE-2

    OpenAIRE

    Pereira, Francisco B.; Gomes, Daniel Gonçalves; Guimarães, Pedro M. R.; Teixeira, J.A.; Domingues, Lucília

    2012-01-01

    A very high gravity (VHG) repeatedbatch fermentation system using an industrial strain of Saccharomyces cerevisiae PE-2 (isolated from sugarcane-to-ethanol distillery in Brazil) and mimicking industrially relevant conditions (high inoculation rates and low O2 availability) was successfully operated during fifteen consecutive fermentation cycles, attaining ethanol at 17.1 ± 0.2% (v/v) with a batch productivity of 3.5 ± 0.04 g l-1 h-1. Moreover, this innovative operat...

  14. Growth and Glucose Repression Are Controlled by Glucose Transport in Saccharomyces cerevisiae Cells Containing Only One Glucose Transporter

    OpenAIRE

    Ye, Ling; Kruckeberg, Arthur L.; Berden, Jan A.; van Dam, Karel

    1999-01-01

    A set of Saccharomyces cerevisiae strains with variable expression of only the high-affinity Hxt7 glucose transporter was constructed by partial deletion of the HXT7 promoter in vitro and integration of the gene at various copy numbers into the genome of an hxt1-7 gal2 deletion strain. The glucose transport capacity increased in strains with higher levels of HXT7 expression. The consequences for various physiological properties of varying the glucose transport capacity were examined. The cont...

  15. Cystathionine accumulation in Saccharomyces cerevisiae.

    OpenAIRE

    Ono, B; Suruga, T; Yamamoto, M.; Yamamoto, S.; Murata, K; Kimura, A; Shinoda, S; Ohmori, S.

    1984-01-01

    A cysteine-dependent strain of Saccharomyces cerevisiae and its prototrophic revertants accumulated cystathionine in cells. The cystathionine accumulation was caused by a single mutation having a high incidence of gene conversion. The mutation was designated cys3 and was shown to cause loss of gamma-cystathionase activity. Cysteine dependence of the initial strain was determined by two linked and interacting mutations, cys3 and cys1 . Since cys1 mutations cause a loss of serine acetyltransfer...

  16. Probe microscopy: Scanning below the cell surface

    Science.gov (United States)

    Sahin, Ozgur

    2008-08-01

    Conventional atomic force microscopy probes only the surface of specimens. A related technique called scanning near-field ultrasonic holography can now image nanoparticles buried below the surfaces of cells, which could prove useful in nanotoxicology.

  17. The pancreatic beta cell surface proteome

    OpenAIRE

    Stützer, I.; Esterházy, D.; Stoffel, M.

    2012-01-01

    The pancreatic beta cell is responsible for maintaining normoglycaemia by secreting an appropriate amount of insulin according to blood glucose levels. The accurate sensing of the beta cell extracellular environment is therefore crucial to this endocrine function and is transmitted via its cell surface proteome. Various surface proteins that mediate or affect beta cell endocrine function have been identified, including growth factor and cytokine receptors, transporters, ion channels and prote...

  18. Surface Functionalization for Protein and Cell Patterning

    Science.gov (United States)

    Colpo, Pascal; Ruiz, Ana; Ceriotti, Laura; Rossi, François

    The interaction of biological systems with synthetic material surfaces is an important issue for many biological applications such as implanted devices, tissue engineering, cell-based sensors and assays, and more generally biologic studies performed ex vivo. To ensure reliable outcomes, the main challenge resides in the ability to design and develop surfaces or artificial micro-environment that mimic 'natural environment' in interacting with biomolecules and cells without altering their function and phenotype. At this effect, microfabrication, surface chemistry and material science play a pivotal role in the design of advanced in-vitro systems for cell culture applications. In this chapter, we discuss and describe different techniques enabling the control of cell-surface interactions, including the description of some techniques for immobilization of ligands for controlling cell-surface interactions and some methodologies for the creation of well confined cell rich areas.

  19. The cell surface of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    1984-01-01

    Full Text Available The cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. The plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. In this paper we will review briefly aspects related to the organization of the cell surface of Trypanosoma cruzi.

  20. The cell surface of Trypanosoma cruzi

    OpenAIRE

    Wanderley de Souza; Thais Souto-Padrón

    1984-01-01

    The cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. The plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. In this paper we will review briefly aspects related to the organization of the cell surface of Trypanosoma cruzi.

  1. Radioimmunoassay to quantitatively measure cell surface immunoglobulins

    International Nuclear Information System (INIS)

    A radioimmunoassay techniques developed to quantitatively measure the presence of immunoglobulins on the surface of cells, is described. The amount of immunoglobulins found on different tumor cells varied from 200 to 1140 ng/106 cells. Determination of immunoglobulins on the peripheral lymphocytes obtained from different cancer patients varied between 340 to 1040 ng/106 cells. Cultured tumor cells, on the other hand, were found to contain negligible quantities of human IgG

  2. Paclitaxel-induced microtubule stabilization causes mitotic block and apoptotic-like cell death in a paclitaxel-sensitive strain of Saccharomyces cerevisiae

    OpenAIRE

    Foland, Travis B.; Dentler, William L.; SUPRENANT, KATHY A.; Gupta, Mohan L.; Himes, Richard H.

    2005-01-01

    Wild-type Saccharomyces cerevisiae tubulin does not bind the anti-mitotic microtubule stabilizing agent paclitaxel. Previously, we introduced mutations into the S. cerevisiae gene for β-tubulin that imparted paclitaxel binding to the protein, but the mutant strain was not sensitive to paclitaxel and other microtubule-stabilizing agents, due to the multiple ABC transporters in the membranes of budding yeast. Here, we introduced the mutated β-tubulin gene into a S. cerevisiae strain with dimini...

  3. Comparative study of bio-ethanol production from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae cells immobilized in agar agar and Ca-alginate matrices

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Shuvashish; Mohanty, Rama Chandra [Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India); Kar, Shaktimay; Ray, Ramesh Chandra [Microbiology Laboratory, Central Tuber Crops Research Institute (Regional Centre), Bhubaneswar 751019, Orissa (India)

    2010-01-15

    Batch fermentation of mahula (Madhuca latifolia L., a tree commonly found in tropical rain forest) flowers was carried out using immobilized cells (in agar agar and calcium alginate) and free cells of Saccharomyces cerevisiae. The ethanol yields were 151.2, 154.5 and 149.1 g kg{sup -1} flowers using immobilized (in agar agar and calcium alginate) and free cells, respectively. Cell entrapment in calcium alginate was found to be marginally superior to those in agar agar (2.2% more) as well as over free cell (3.5% more) as regard to ethanol yield from mahula flowers is concerned. Further, the immobilized cells were physiologically active at least for three cycles [150.6, 148.5 and 146.5 g kg{sup -1} (agar agar) and 152.8, 151.5 and 149.5 g kg{sup -1} flowers (calcium alginate) for first, second and third cycle, respectively] of ethanol fermentation without apparently lowering the productivity. Mahula flowers, a renewable, non-food-grade cheap carbohydrate substrate from non-agricultural environment such as forest can serve as an alternative to food grade sugar/starchy crops such as maize, sugarcane for bio-ethanol production. (author)

  4. Antimicrobial peptides (AMPs) produced by Saccharomyces cerevisiae induce alterations in the intracellular pH, membrane permeability and culturability of Hanseniaspora guilliermondii cells.

    Science.gov (United States)

    Branco, Patrícia; Viana, Tiago; Albergaria, Helena; Arneborg, Nils

    2015-07-16

    Saccharomyces cerevisiae produces antimicrobial peptides (AMPs) during alcoholic fermentation that are active against several wine-related yeasts (e.g. Hanseniaspora guilliermondii) and bacteria (e.g. Oenococcus oeni). In the present study, the physiological changes induced by those AMPs on sensitive H. guilliermondii cells were evaluated in terms of intracellular pH (pHi), membrane permeability and culturability. Membrane permeability was evaluated by staining cells with propidium iodide (PI), pHi was determined by a fluorescence ratio imaging microscopy (FRIM) technique and culturability by a classical plating method. Results showed that the average pHi of H. guilliermondii cells dropped from 6.5 (healthy cells) to 5.4 (damaged cells) after 20 min of exposure to inhibitory concentrations of AMPs, and after 24 h 77.0% of the cells completely lost their pH gradient (∆pH=pHi-pHext). After 24h of exposure to AMPs, PI-stained (dead) cells increased from 0% to 77.7% and the number of viable cells fell from 1×10(5) to 10 CFU/ml. This means that virtually all cells (99.99%) became unculturable but that a sub-population of 22.3% of the cells remained viable (as determined by PI staining). Besides, pHi results showed that after 24h, 23% of the AMP-treated cells were sub-lethally injured (with 0<∆pH<3). Taken together, these results indicated that this subpopulation was under a viable but non-culturable (VBNC) state, which was further confirmed by recuperation assays. In summary, our study reveals that these AMPs compromise the plasma membrane integrity (and possibly also the vacuole membrane) of H. guilliermondii cells, disturbing the pHi homeostasis and inducing a loss of culturability. PMID:25897995

  5. Nanostructuring of Solar Cell Surfaces

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

    Solar energy is by far the most abundant renewable energy source available, but the levelized cost of solar energy is still not competitive with that of fossil fuels. Therefore there is a need to improve the power conversion effciency of solar cells without adding to the production cost. The main...... objective of this PhD thesis is to develop nanostructured silicon (Si) solar cells with higher power conversion efficiency using only scalable and cost-efficient production methods. The nanostructures, known as 'black silicon', are fabricated by single-step, maskless reactive ion etching and used as front...... and characterized for comparison. Power conversion eciency of 16.5% was obtained for this batch of RIE-textured Si solar cells. The eciency of the KOH-textured reference cell was 17.8%. Quantum Efficiency measurements and carrier loss analysis show that the lower eciency of the RIE-textured cells is primarily due...

  6. Cell behaviour on chemically microstructured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Magnani, Agnese; Priamo, Alfredo; Pasqui, Daniela; Barbucci, Rolando

    2003-03-03

    Micropatterned surfaces with different chemical topographies were synthesised in order to investigate the influence of surface chemistry and topography on cell behaviour. The microstructured materials were synthesised by photoimmobilising natural Hyaluronan (Hyal) and its sulphated derivative (HyalS), both adequately functionalised with a photorective moiety, on glass substrates. Four different grating patterns (10, 25, 50 and 100 {mu}m) were used to pattern the hyaluronan. The micropatterned samples were analysed by Secondary Ions Mass Spectrometry, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy to investigate the chemistry and the topography of the surfaces. The spectroscopic and microscopic analysis of the microstructured surfaces revealed that the photoimmobilisation process was successful, demonstrating that the photomask patterns were well reproduced on the sample surface. The influence of chemical topographies on the cell behaviour was then analysed. Human and 3T3 fibroblasts, bovine aortic and human (HGTFN line) endothelial cells were used and their behaviour on the micropatterned surfaces was analysed in terms of adhesion, proliferation, locomotion and orientation. Both chemical and topographical controls were found to be important for cell guidance. By decreasing the stripe dimensions, a more fusiform shape of cell was observed. At the same time, the cell locomotion and orientation parallel to the structure increased. However, differences in cell behaviour were detected according to both cell type and micropattern dimensions.

  7. Incorporation of Nasutitermes takasagoensis endoglucanase into cell surface-displayed minicellulosomes in Pichia pastoris X33.

    Science.gov (United States)

    Ou, Jingshen; Cao, Yicheng

    2014-09-01

    In this study, the yeast Pichia pastoris was genetically modified to assemble minicellulosomes on its cell surface by the heterologous expression of a truncated scaffoldin CipA from Clostridium acetobutylicum. Fluorescence microscopy and western blot analysis confirmed that CipA was targeted to the yeast cell surface and that NtEGD, the Nasutitermes takasagoensis endoglucanase that was fused with dockerin, interacted with CipA on the yeast cell surface, suggesting that the cohesin and dockerin domains and cellulose-binding module of C. acetobutylicum were functional in the yeasts. The enzymatic activities of the cellulases in the minicellulosomes that were displayed on the yeast cell surfaces increased dramatically following interaction with the cohesin-dockerin domains. Additionally, the hydrolysis efficiencies of NtEGD for carboxymethyl cellulose, microcrystal cellulose, and filter paper increased up to 1.4-fold, 2.0-fold, and 3.2-fold, respectively. To the best of our knowledge, this is the first report describing the expression of C. acetobutylicum minicellulosomes in yeast and the incorporation of animal cellulases into cellulosomes. This strategy of heterologous cellulase incorporation lends novel insight into the process of cellulosome assembly. Potentially, the surface display of cellulosomes, such as that reported in this study, may be utilized in the engineering of S. cerevisiae for ethanol production from cellulose and additional future applications. PMID:24851815

  8. The SFP1 gene product of Saccharomyces cerevisiae regulates G2/M transitions during the mitotic cell cycle and DNA-damage response

    International Nuclear Information System (INIS)

    In eukaryotic cells, checkpoint pathways arrest cell-cycle progression if a particular event has failed to complete appropriately or if an important intracellular structure is defective or damaged. Saccharomyces cerevisiae strains that lack the SFP1 gene fail to arrest at the G2 DNA-damage checkpoint in response to genomic injury, but maintain their ability to arrest at the replication and spindle-assembly checkpoints. sfp1D mutants are characterized by a premature entrance into mitosis during a normal (undamaged) cell cycle, while strains that overexpress Sfp1p exhibit delays in G2. Sfp1p therefore acts as a repressor of the G2/M transition, both in the normal cell cycle and in the G2 checkpoint pathway. Sfp1 is a nuclear protein with two Cys2His2 zinc-finger domains commonly found in transcription factors. We propose that Sfp1p regulates the expression of gene products involved in the G2/M transition during the mitotic cell cycle and the DNA-damage response. In support of this model, overexpression of Sfp1p induces the expression of the PDS1 gene, which is known to encode a protein that regulates the G2 checkpoint. (author)

  9. High vacuum cells for classical surface techniques

    International Nuclear Information System (INIS)

    Novel glass cells were designed and built to be able to perform surface potential and surface tension measurements in a contained environment. The cells can withstand pressures of approximately 1x10-6 Torr, providing a reasonable level of control in terms of the amounts of volatile contaminants during experimentation. The measurements can take several hours; thus the cells help maintain the integrity of the sample in the course of the experiment. To test for the feasibility of the cell design, calibration measurements were performed. For the surface potential cell, the modified TREK 6000B-7C probe exhibited performance comparable to its unmodified counterpart. The correlation measurements between applied potential on the test surface and the measured potential showed R-values very close to 1 as well as standard deviation values of less than 1. Results also demonstrate improved measurement values for experiments performed in vacuum. The surface tension cell, on the other hand, which was used to perform the pendant drop method, was tested on common liquids and showed percentage errors of 0.5% when compared to literature values. The fabricated cells redefine measurements using classical surface techniques, providing unique and novel methods of sample preparation, premeasurement preparation, and sample analysis at highly beneficial expenditure cost.

  10. Function of SSA subfamily of Hsp70 within and across species varies widely in complementing Saccharomyces cerevisiae cell growth and prion propagation.

    Directory of Open Access Journals (Sweden)

    Deepak Sharma

    Full Text Available BACKGROUND: The cytosol of most eukaryotic cells contains multiple highly conserved Hsp70 orthologs that differ mainly by their spatio-temporal expression patterns. Hsp70s play essential roles in protein folding, transport or degradation, and are major players of cellular quality control processes. However, while several reports suggest that specialized functions of Hsp70 orthologs were selected through evolution, few studies addressed systematically this issue. METHODOLOGY/PRINCIPAL FINDINGS: We compared the ability of Ssa1p-Ssa4p from Saccharomyces cerevisiae and Ssa5p-Ssa8p from the evolutionary distant yeast Yarrowia lipolytica to perform Hsp70-dependent tasks when expressed as the sole Hsp70 for S. cerevisiae in vivo. We show that Hsp70 isoforms (i supported yeast viability yet with markedly different growth rates, (ii influenced the propagation and stability of the [PSI(+] and [URE3] prions, but iii did not significantly affect the proteasomal degradation rate of CFTR. Additionally, we show that individual Hsp70 orthologs did not induce the formation of different prion strains, but rather influenced the aggregation properties of Sup35 in vivo. Finally, we show that [URE3] curing by the overexpression of Ydj1p is Hsp70-isoform dependent. CONCLUSION/SIGNIFICANCE: Despite very high homology and overlapping functions, the different Hsp70 orthologs have evolved to possess distinct activities that are required to cope with different types of substrates or stress situations. Yeast prions provide a very sensitive model to uncover this functional specialization and to explore the intricate network of chaperone/co-chaperone/substrates interactions.

  11. Functional dynamics of cell surface membrane proteins

    Science.gov (United States)

    Nishida, Noritaka; Osawa, Masanori; Takeuchi, Koh; Imai, Shunsuke; Stampoulis, Pavlos; Kofuku, Yutaka; Ueda, Takumi; Shimada, Ichio

    2014-04-01

    Cell surface receptors are integral membrane proteins that receive external stimuli, and transmit signals across plasma membranes. In the conventional view of receptor activation, ligand binding to the extracellular side of the receptor induces conformational changes, which convert the structure of the receptor into an active conformation. However, recent NMR studies of cell surface membrane proteins have revealed that their structures are more dynamic than previously envisioned, and they fluctuate between multiple conformations in an equilibrium on various timescales. In addition, NMR analyses, along with biochemical and cell biological experiments indicated that such dynamical properties are critical for the proper functions of the receptors. In this review, we will describe several NMR studies that revealed direct linkage between the structural dynamics and the functions of the cell surface membrane proteins, such as G-protein coupled receptors (GPCRs), ion channels, membrane transporters, and cell adhesion molecules.

  12. Adhesion of cells to polystyrene surfaces

    OpenAIRE

    1983-01-01

    The surface treatment of polystyrene, which is required to make polystyrene suitable for cell adhesion and spreading, was investigated. Examination of surfaces treated with sulfuric acid or various oxidizing agents using (a) x-ray photoelectron and attenuated total reflection spectroscopy and (b) measurement of surface carboxyl-, hydroxyl-, and sulfur-containing groups by various radiochemical methods showed that sulfuric acid produces an insignificant number of sulfonic acid groups on polyst...

  13. Nanotomography of Cell Surfaces with Evanescent Fields

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2008-01-01

    Full Text Available The technique of variable-angle total internal reflection fluorescence microscopy (TIRFM and its application to nanotomography of cell surfaces are described. Present applications include (1 3D imaging of chromosomes in their metaphase to demonstrate axial resolution in the nanometre range, (2 measurements of cell-substrate topology, which upon cholesterol depletion shows some loosening of cell-substrate contacts, and (3 measurements of cell topology upon photodynamic therapy (PDT, which demonstrate cell swelling and maintenance of focal contacts. The potential of the method for in vitro diagnostics, but also some requirements and limitations are discussed.

  14. Cell Adhesion on Surface-Functionalized Magnesium.

    Science.gov (United States)

    Wagener, Victoria; Schilling, Achim; Mainka, Astrid; Hennig, Diana; Gerum, Richard; Kelch, Marie-Luise; Keim, Simon; Fabry, Ben; Virtanen, Sannakaisa

    2016-05-18

    The biocompatibility of commercially pure magnesium-based (cp Mg) biodegradable implants is compromised of strong hydrogen evolution and surface alkalization due to high initial corrosion rates of cp Mg in the physiological environment. To mitigate this problem, the addition of corrosion-retarding alloying elements or coating of implant surfaces has been suggested. In the following work, we explored the effect of organic coatings on long-term cell growth. cp Mg was coated with aminopropyltriehtoxysilane + vitamin C (AV), carbonyldiimidazole (CDI), or stearic acid (SA). All three coatings have been previously suggested to reduce initial corrosion and to enhance protein adsorption and hence cell adhesion on magnesium surfaces. Endothelial cells (DH1+/+) and osteosarcoma cells (MG63) were cultured on coated samples for up to 20 days. To quantify Mg corrosion, electrochemical impedance spectroscopy (EIS) was measured after 1, 3, and 5 days of cell culture. We also investigated the speed of initial cell spreading after seeding using fluorescently labeled fibroblasts (NIH/3T3). Hydrogen evolution after contact with cell culture medium was markedly decreased on AV- and SA-coated Mg compared to uncoated Mg. These coatings also showed improved cell adhesion and spreading after 24 h of culture comparable to tissue-treated plastic surfaces. On AV-coated cp Mg, a confluent layer of endothelial cells formed after 5 days and remained intact for up to 20 days. Together, these data demonstrate that surface coating with AV is a viable strategy for improving long-term biocompatibility of cp Mg-based implants. EIS measurements confirmed that the presence of a confluent cell layer increased the corrosion resistance. PMID:27089250

  15. Development of yeast cell factories for consolidated bioprocessing of lignocellulose to bioethanol through cell surface engineering.

    Science.gov (United States)

    Hasunuma, Tomohisa; Kondo, Akihiko

    2012-01-01

    To build an energy and material secure future, a next generation of renewable fuels produced from lignocellulosic biomass is required. Although lignocellulosic biomass, which represents an abundant, inexpensive and renewable source for bioethanol production, is of great interest as a feedstock, the complicated ethanol production processes involved make the cost of producing bioethanol from it higher compared to corn starch and cane juice. Therefore, consolidated bioprocessing (CBP), which combines enzyme production, saccharification and fermentation in a single step, has gained increased recognition as a potential bioethanol production system. CBP requires a highly engineered microorganism developed for several different process-specific characteristics. The dominant strategy for engineering a CBP biocatalyst is to express multiple components of a cellulolytic system from either fungi or bacteria in the yeast Saccharomyces cerevisiae. The development of recombinant yeast strains displaying cellulases and hemicellulases on the cell surface represents significant progress toward realization of CBP. Regardless of the process used for biomass hydrolysis, CBP-enabling microorganisms encounter a variety of toxic compounds produced during biomass pretreatment that inhibit microbial growth and ethanol yield. Systems biology approaches including disruptome screening, transcriptomics, and metabolomics have been recently exploited to gain insight into the molecular and genetic traits involved in tolerance and adaptation to the fermentation inhibitors. In this review, we focus on recent advances in development of yeast strains with both the ability to directly convert lignocellulosic material to ethanol and tolerance in the harsh environments containing toxic compounds in the presence of ethanol. PMID:22085593

  16. Oscillations in glycolysis in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Kloster, Antonina; Olsen, Lars Folke

    Wehave investigated the glycolytic oscillations, measured as NADH autofluorescence, in the yeast Saccharomyces cerevisiae in a batch reactor. Specifically, we have tested the effect of cell density and a number of inhibitors or activators of ATPase activity on the amplitude of the oscillations. The...

  17. Yeast Bax inhibitor, Bxi1p, is an ER-localized protein that links the unfolded protein response and programmed cell death in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    James Cebulski

    Full Text Available Bax inhibitor-1 (BI-1 is an anti-apoptotic gene whose expression is upregulated in a wide range of human cancers. Studies in both mammalian and plant cells suggest that the BI-1 protein resides in the endoplasmic reticulum and is involved in the unfolded protein response (UPR that is triggered by ER stress. It is thought to act via a mechanism involving altered calcium dynamics. In this paper, we provide evidence that the Saccharomyces cerevisiae protein encoded by the open reading frame, YNL305C, is a bona fide homolog for BI-1. First, we confirm that yeast cells from two different strain backgrounds lacking YNL305C, which we have renamed BXI1, are more sensitive to heat-shock induced cell death than wildtype controls even though they have indistinguishable growth rates at 30°C. They are also more susceptible both to ethanol-induced and to glucose-induced programmed cell death. Significantly, we show that Bxi1p-GFP colocalizes with the ER localized protein Sec63p-RFP. We have also discovered that Δbxi1 cells are not only more sensitive to drugs that induce ER stress, but also have a decreased unfolded protein response as measured with a UPRE-lacZ reporter. Finally, we have discovered that deleting BXI1 diminishes the calcium signaling response in response to the accumulation of unfolded proteins in the ER as measured by a calcineurin-dependent CDRE-lacZ reporter. In toto, our data suggests that the Bxi1p, like its metazoan homologs, is an ER-localized protein that links the unfolded protein response and programmed cell death.

  18. Anaerobic and sequential aerobic production of high-titer ethanol and single cell protein from NaOH-pretreated corn stover by a genome shuffling-modified Saccharomyces cerevisiae strain.

    Science.gov (United States)

    Ren, Xueliang; Wang, Juncong; Yu, Hui; Peng, Chunlan; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Liang, Yunxiang; Peng, Nan

    2016-10-01

    In this study, a Saccharomyces cerevisiae recombinant strain 14 was constructed through genome shuffling method by transferring the whole genomic DNA of Candida intermedia strain 23 into a thermo-tolerant S. cerevisiae strain. The recombinant strain 14 combined the good natures of both parent strains that efficiently produced ethanol from glucose and single cell protein from xylose with 54.6% crude protein and all essential amino acids except cysteine at 35°C. Importantly, the recombinant strain 14 produced 64.07g/L ethanol from 25%(w/v) NaOH-pretreated and washed corn stover with the ethanol yield of 0.26g/g total stover by fed-batch simultaneous saccharification and fermentation and produced 66.50g/L dry cell mass subsequently from the residual hydrolysate and ethanol. Therefore, this study represents a feasible method to comprehensively utilize hexose and pentose in lignocellulosic materials. PMID:27416512

  19. Studies of DNA repair in Saccharomyces cerevisiae. I. Characterization of a new allele of RAD6. II. Investigation of events in the first cell cycle after DNA damage

    International Nuclear Information System (INIS)

    Studies in two independent, but related, areas of DNA repair have been carried out in the eucaryotic yeast, Saccharomyces cerevisiae. The first is the characterization of a new allele in the RAD6 gene suggesting that the gene is multifunctional. The second is the utilization of photoreactivation as a probe of events occurring during the first cell cycle after DNA damage. Strains carrying the new allele, designated rad6-4, of the RAD6 locus are about as sensitive to uv and ionizing radiation as those carrying rad6-1 or rad6-3. Although rad6-4 may well be a missense mutation, the data suggest that the RAD6 gene is multifunctional. One function is necessary to recover from DNA damage in an error-free manner, and the other is concerned with mutagenic processes and sporulation. The loss of photoreversibility (LOP) of ultraviolet induced mutations to arginine independence in an excision defective strain carrying arg4-17 examines the events occurring in the first cell cycle. The post uv protein synthesis causes pyrimidine dimmers to become inaccessible to the photoreactivating enzyme in some unknown manner. There is no evidence indicating whether the normal function of the protein is involved in excision repair, or in one of the two repair processes believed to be inducible; induced mutagenesis or recombinational repair

  20. Stationary phase in the yeast Saccharomyces cerevisiae.

    OpenAIRE

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

    1993-01-01

    Growth and proliferation of microorganisms such as the yeast Saccharomyces cerevisiae are controlled in part by the availability of nutrients. When proliferating yeast cells exhaust available nutrients, they enter a stationary phase characterized by cell cycle arrest and specific physiological, biochemical, and morphological changes. These changes include thickening of the cell wall, accumulation of reserve carbohydrates, and acquisition of thermotolerance. Recent characterization of mutant c...

  1. Immobilized Saccharomyces cerevisiae as a potential aflatoxin decontaminating agent in pistachio nuts

    Directory of Open Access Journals (Sweden)

    S. Rahaie

    2010-03-01

    Full Text Available In this study, we investigated the binding ability of Saccharomayces cerevisiae to aflatoxin in pistachio nuts. The obtained results indicate that S. cerevisiae has an aflatoxin surface binding ability of 40% and 70% (with initial aflatoxin concentrations of 10 and 20 ppb in the exponential phase. Acid treatments increase this ability to approximately 60% and 73% for the two concentrations of aflatoxin, respectively. Heat treatments also enhance surface binding to 55% and 75%, respectively. Binding appears to be a physical phenomenon that saturates within the first 2-3 hours of the process. The obtained results indicate that yeast immobilization for toxin reduction on aflatoxin-contaminated pistachios had no effect on qualitative characteristics, such as color, texture, and peroxide value. Yeast cells, viable or nonviable, are effective for aflatoxin binding, and this property could lead to a promising solution to aflatoxin contamination in high-risk foods.

  2. Use of Saccharum spontaneum (wild sugarcane) as biomaterial for cell immobilization and modulated ethanol production by thermotolerant Saccharomyces cerevisiae VS3.

    Science.gov (United States)

    Chandel, Anuj K; Narasu, M Lakshmi; Chandrasekhar, G; Manikyam, A; Rao, L Venkateswar

    2009-04-01

    Saccharum spontaneum is a wasteland weed consists of 45.10+/-0.35% cellulose and 22.75+/-0.28% of hemicellulose on dry solid (DS) basis. Aqueous ammonia delignified S. spontaneum yielded total reducing sugars, 53.91+/-0.44 g/L (539.10+/-0.55 mg/g of substrate) with a hydrolytic efficiency of 77.85+/-0.45%. The enzymes required for hydrolysis were prepared from culture supernatants of Aspergillus oryzae MTCC 1846. A maximum of 0.85+/-0.07 IU/mL of filter paperase (FPase), 1.25+/-0.04 IU/mL of carboxy methyl cellulase (CMCase) and 55.56+/-0.52 IU/mL of xylanase activity was obtained after 7 days of incubation at 28+/-0.5 degrees C using delignified S. spontaneum as carbon source under submerged fermentation conditions. Enzymatic hydrolysate of S. spontaneum was then tested for ethanol production under batch and repeated batch production system using "in-situ" entrapped Saccharomyces cerevisiae VS3 cells in S. spontaneum stalks (1 cm x 1 cm) size. Immobilization was confirmed by the scanning electron microscopy (SEM). Batch fermentation of VS3 free cells and immobilized cells showed ethanol production, 19.45+/-0.55 g/L (yield, 0.410+/-0.010 g/g) and 21.66+/-0.62 g/L (yield, 0.434+/-0.021 g/g), respectively. Immobilized VS3 cells showed maximum ethanol production (22.85+/-0.44 g/L, yield, 0.45+/-0.04 g/g) up to 8th cycle during repeated batch fermentation followed by a gradual reduction in subsequent cycles of fermentation. PMID:19114303

  3. 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

    nontumorigenic porcine jejunal epithelial cell line (IPEC-J2) was investigated by incorporation of H-3-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...... effects hence indicating that food-borne strains of S. cerevisiae may possess probiotic properties in spite of low adhesiveness. © 2004 Elsevier B.V. All rights reserved....

  4. Conclusion on the peer review of the pesticide risk assessment of the active substance cerevisane (cell walls of Saccharomyces cerevisiae strain LAS117

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2014-06-01

    Full Text Available The conclusions of the European Food Safety Authority (EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State France for the pesticide active substance cerevisane (cell walls of Saccharomyces cerevisiae strain LAS117, and the assessment of the proposal for inclusion of the substance in Annex IV of Regulation (EC No 396/2005, are reported. The context of the peer review was that required by Regulation (EC No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of the active substance as a systemic resistance inducer against fungi and bacteria in lettuce and other salad crops. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. No concerns are identified.

  5. 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.

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

    International Nuclear Information System (INIS)

    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 (λex = 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

  7. 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.

  8. Compréhension des mécanismes à l’origine de l’adhésion de Saccharomyces cerevisiae sur acier inoxydable: Implications pour l’hygiène des surfaces en industrie agroalimentaire

    OpenAIRE

    Guillemot, Gaëlle

    2006-01-01

    Dans l’industrie agroalimentaire, l’adhésion de microorganismes contaminants sur les surfaces induit des effets néfastes à la fois en terme de qualité, d’hygiène et de santé publique. Dans cette étude, une forte adhésion de Saccharomyces cerevisiae sur l’acier inoxydable a été mise en évidence, à l’aide d’une chambre à écoulement cisaillé. La spécificité de ce matériau par rapport à d’autres surfaces « contrôle » a été démontrée pour des souches de levures d’origine variée. Cette spécificité ...

  9. Iron, copper, and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress.

    Science.gov (United States)

    Ribeiro, Thales P; Fernandes, Christiane; Melo, Karen V; Ferreira, Sarah S; Lessa, Josane A; Franco, Roberto W A; Schenk, Gerhard; Pereira, Marcos D; Horn, Adolfo

    2015-03-01

    Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50~0.4 μmol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O2(•-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O2(•-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III)>copper(II)>manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. PMID:25511255

  10. Engineering novel cell surface chemistry for selective tumor cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, C.R. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    A common feature of many different cancers is the high expression level of the two monosaccharides sialic acid and fucose within the context of cell-surface associated glycoconjugates. A correlation has been made between hypersialylation and/or hyperfucosylation and the highly metastatic phenotype. Thus, a targeting strategy based on sialic acid or fucose expression would be a powerful tool for the development of new cancer cell-selective therapies and diagnostic agents. We have discovered that ketone groups can be incorporated metabolically into cell-surface associated sialic acids. The ketone is can be covalently ligated with hydrazide functionalized proteins or small molecules under physiological conditions. Thus, we have discovered a mechanism to selectively target hydrazide conjugates to highly sialylated cells such as cancer cells. Applications of this technology to the generation of novel cancer cell-selective toxins and MRI contrast reagents will be discussed, in addition to progress towards the use of cell surface fucose residues as vehicles for ketone expression.

  11. Regulatory mechanisms controlling expression of the DAN/TIR mannoprotein genes during anaerobic remodeling of the cell wall in Saccharomyces cerevisiae.

    Science.gov (United States)

    Abramova, N E; Cohen, B D; Sertil, O; Kapoor, R; Davies, K J; Lowry, C V

    2001-03-01

    The DAN/TIR genes of Saccharomyces cerevisiae encode homologous mannoproteins, some of which are essential for anaerobic growth. Expression of these genes is induced during anaerobiosis and in some cases during cold shock. We show that several heme-responsive mechanisms combine to regulate DAN/TIR gene expression. The first mechanism employs two repression factors, Mox1 and Mox2, and an activation factor, Mox4 (for mannoprotein regulation by oxygen). The genes encoding these proteins were identified by selecting for recessive mutants with altered regulation of a dan1::ura3 fusion. MOX4 is identical to UPC2, encoding a binucleate zinc cluster protein controlling expression of an anaerobic sterol transport system. Mox4/Upc2 is required for expression of all the DAN/TIR genes. It appears to act through a consensus sequence termed the AR1 site, as does Mox2. The noninducible mox4Delta allele was epistatic to the constitutive mox1 and mox2 mutations, suggesting that Mox1 and Mox2 modulate activation by Mox4 in a heme-dependent fashion. Mutations in a putative repression domain in Mox4 caused constitutive expression of the DAN/TIR genes, indicating a role for this domain in heme repression. MOX4 expression is induced both in anaerobic and cold-shocked cells, so heme may also regulate DAN/TIR expression through inhibition of expression of MOX4. Indeed, ectopic expression of MOX4 in aerobic cells resulted in partially constitutive expression of DAN1. Heme also regulates expression of some of the DAN/TIR genes through the Rox7 repressor, which also controls expression of the hypoxic gene ANB1. In addition Rox1, another heme-responsive repressor, and the global repressors Tup1 and Ssn6 are also required for full aerobic repression of these genes. PMID:11238402

  12. Studies of DNA repair in saccharomyces cerevisiae. I. Characterization of a new allele of RAD6. II. Investigation of events in the first cell cycle after DNA damage

    International Nuclear Information System (INIS)

    Studies in two independent, but related, areas of DNA repair have been carried out in Saccharomyces cerevisiae; characterization of a new allele in the RAD6 gene which suggests that the gene is multifunctional, and utilization of photoreactivation as a probe of events occurring during the first cell cycle after DNA damage. Strains carrying the new allele, designated rad6-4, are as sensitive to uv and ionizing radiation as those carrying rad6-1 or rad6-3 but, unlike them, are capable of induced mutagenesis and sporulation. Although rad6-4 may well be a missense mutation, the evidence shows that it is unlikely that this phenotype is due to leakiness. Instead, the data suggest that the RAD6 gene is multifunctional. One function is necessary to recover from DNA damage in an error-free manner, and the other is concerned with mutagenic processes and sporulation. Rad6-1 and rad6-3 strains are deficient in both of these functions, while rad6-4 strains are deficient only in the error-free function. The loss of photoreversibility (LOP) of ultraviolet induced mutations to arginine independence in an excision defective strain carrying arg4-17 examines the events occurring in the first cell cycle after DNA damage. LOP is dependent upon de novo protein synthesis. LOP begins immediately after UV irradiation, before semiconservative DNA synthesis takes place, and is complete after four hours in growth medium.There is no evidence indicating whether the normal function of the protein is involved in excision repair, or in one of the two repair processes believed to be inducible; induced mutagenesis or recombinational repair

  13. Global mRNA expression analysis in myosin II deficient strains of Saccharomyces cerevisiae reveals an impairment of cell integrity functions

    Directory of Open Access Journals (Sweden)

    Rivera-Molina Félix E

    2008-01-01

    Full Text Available Abstract Background The Saccharomyces cerevisiae MYO1 gene encodes the myosin II heavy chain (Myo1p, a protein required for normal cytokinesis in budding yeast. Myo1p deficiency in yeast (myo1Δ causes a cell separation defect characterized by the formation of attached cells, yet it also causes abnormal budding patterns, formation of enlarged and elongated cells, increased osmotic sensitivity, delocalized chitin deposition, increased chitin synthesis, and hypersensitivity to the chitin synthase III inhibitor Nikkomycin Z. To determine how differential expression of genes is related to these diverse cell wall phenotypes, we analyzed the global mRNA expression profile of myo1Δ strains. Results Global mRNA expression profiles of myo1Δ strains and their corresponding wild type controls were obtained by hybridization to yeast oligonucleotide microarrays. Results for selected genes were confirmed by real time RT-PCR. A total of 547 differentially expressed genes (p ≤ 0.01 were identified with 263 up regulated and 284 down regulated genes in the myo1Δ strains. Gene set enrichment analysis revealed the significant over-representation of genes in the protein biosynthesis and stress response categories. The SLT2/MPK1 gene was up regulated in the microarray, and a myo1Δslt2Δ double mutant was non-viable. Overexpression of ribosomal protein genes RPL30 and RPS31 suppressed the hypersensitivity to Nikkomycin Z and increased the levels of phosphorylated Slt2p in myo1Δ strains. Increased levels of phosphorylated Slt2p were also observed in wild type strains under these conditions. Conclusion Following this analysis of global mRNA expression in yeast myo1Δ strains, we conclude that 547 genes were differentially regulated in myo1Δ strains and that the stress response and protein biosynthesis gene categories were coordinately regulated in this mutant. The SLT2/MPK1 gene was confirmed to be essential for myo1Δ strain viability, supporting that the up

  14. Metabolic behavior of cell surface biotinylated proteins

    International Nuclear Information System (INIS)

    The turnover of proteins on the surface of cultured mammalian cells was measured by a new approach. Reactive free amino or sulfhydryl groups on surface-accessible proteins were derivatized with biotinyl reagents and the proteins solubilized from culture dishes with detergent. Solubilized, biotinylated proteins were then adsorbed onto streptavidin-agarose, released with sodium dodecyl sulfate and mercaptoethanol, and separated on polyacrylamide gels. Biotin-epsilon-aminocaproic acid N-hydroxysuccinimide ester (BNHS) or N-biotinoyl-N'-(maleimidohexanoyl)hydrazine (BM) were the derivatizing agents. Only 10-12 bands were adsorbed onto streptavidin-agarose from undervatized cells or from derivatized cells treated with free avidin at 4 degrees C. Two-dimensional isoelectric focusing-sodium dodecyl sulfate gel electrophoresis resolved greater than 100 BNHS-derivatized proteins and greater than 40 BM-derivatized proteins. There appeared to be little overlap between the two groups of derivatized proteins. Short-term pulse-chase studies showed an accumulation of label into both groups of biotinylated proteins up until 1-2 h of chase and a rapid decrease over the next 1-5 h. Delayed appearance of labeled protein at the cell surface was attributed to transit time from site of synthesis. The unexpected and unexplained rapid disappearance of pulse-labeled proteins from the cell surface was invariant for all two-dimensionally resolved proteins and was sensitive to temperature reduction to 18 degrees C. Long-term pulse-chase experiments beginning 4-8 h after the initiation of chase showed the disappearance of derivatized proteins to be a simple first-order process having a half-life of 115 h in the case of BNHS-derivatized proteins and 30 h in the case of BM-derivatized proteins

  15. Genetic Basis for Saccharomyces cerevisiae Biofilm in Liquid Medium

    DEFF Research Database (Denmark)

    Andersen, Kaj Scherz; Bojsen, Rasmus Kenneth; Gro Rejkjær Sørensen, Laura; Weiss Nielsen, Martin; Lisby, Michael; Folkesson, Sven Anders; Regenberg, Birgitte

    2014-01-01

    Biofilm-forming microorganisms switch between two forms: free-living planktonic and sessile multicellular. Sessile communities of yeast biofilms in liquid medium provide a primitive example of multicellularity and are clinically important because biofilms tend to have other growth characteristics...... 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...... functioned specifically in biofilm and mat formation. In a tpk3 mutant, transcription of FLO11 was induced three-fold compared with wild-type, but biofilm development and cell–cell adhesion was absent, suggesting that Tpk3p regulates FLO11 positive posttranscriptionally and negative transcriptionally. The...

  16. The cell-surface proteome of cultured adipose stromal cells.

    Science.gov (United States)

    Donnenberg, Albert D; Meyer, E Michael; Rubin, J Peter; Donnenberg, Vera S

    2015-07-01

    In this technical note we describe a method to evaluate the cell surface proteome of human primary cell cultures and cell lines. The method utilizes the BD Biosciences lyoplate, a system covering 242 surface proteins, glycoproteins, and glycosphingolipids plus relevant isotype controls, automated plate-based flow cytometry, conventional file-level analysis and unsupervised K-means clustering of markers on the basis of percent of positive events and mean fluorescence intensity of positive and total clean events. As an example, we determined the cell surface proteome of cultured adipose stromal cells (ASC) derived from 5 independent clinical isolates. Between-sample agreement of very strongly expressed (n = 32) and strongly expressed (n =16) markers was excellent, constituting a reliable profile for ASC identification and determination of functional properties. Known mesenchymal markers (CD29, CD44, CD73, CD90, CD105) were among the identified strongly expressed determinants. Among other strongly expressed markers are several that are potentially immunomodulatory including three proteins that protect from complement mediated effects (CD46, CD55, and CD59), two that regulate apoptosis (CD77 and CD95) and several with ectoenzymatic (CD10, CD26, CD13, CD73, and CD143) or receptor tyrosine kinase (CD140b (PDGFR), CD340 (Her-2), EGFR) activity, suggesting mechanisms for the anti-inflammatory and tissue remodeling properties of ASC. Because variables are standardized for K-means clustering, results generated using this methodology should be comparable between instrumentation platforms. It is widely generalizable to human primary explant cultures and cells lines and will prove useful to determine how cell passage, culture interventions, and gene expression and silencing affect the cell-surface proteome. PMID:25929697

  17. Recovery of Saccharomyces cerevisiae from ethanol-induced growth inhibition.

    OpenAIRE

    Walker-Caprioglio, H M; Rodriguez, R J; Parks, L. W.

    1985-01-01

    Ethanol caused altered mobility of the lipophilic probe 1,6-diphenyl-1,3,5-hexatriene in plasma membrane preparations of Saccharomyces cerevisiae. Because lipids had been shown to protect yeast cells against ethanol toxicity, sterols, fatty acids, proteins, and combinations of these were tested; however, protection from growth inhibition was not seen. Ethanol-induced, prolonged lag periods and diminished growth rates in S. cerevisiae were reduced by an autoconditioning of the medium by the in...

  18. Cell Surface Markers in HTLV-1 Pathogenesis

    Directory of Open Access Journals (Sweden)

    Andrea K. Kress

    2011-08-01

    Full Text Available The phenotype of HTLV-1-transformed CD4+ T lymphocytes largely depends on defined viral effector molecules such as the viral oncoprotein Tax. In this review, we exemplify the expression pattern of characteristic lineage markers, costimulatory receptors and ligands of the tumor necrosis factor superfamily, cytokine receptors, and adhesion molecules on HTLV-1-transformed cells. These molecules may provide survival signals for the transformed cells. Expression of characteristic surface markers might therefore contribute to persistence of HTLV-1-transformed lymphocytes and to the development of HTLV-1-associated disease.

  19. Bioactive sugar surfaces for hepatocyte cell culture

    OpenAIRE

    Ambury, Rachael

    2010-01-01

    The primary objective of this study was to identify, develop and characterise a novel bioactive surface capable of binding hepatocytes and enabling the retention of hepatocyte-specific cell function during in-vitro culture. The materials were designed to exploit a unique characteristic of hepatocyte biology, with β-galactose moieties displayed to allow cellular adhesion via the specific asialoglycoprotein receptors (ASGP-R) found on hepatocytes. Hydrogels were created by modifying a commercia...

  20. 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.

  1. A novel mutant of the Sup35 protein of Saccharomyces cerevisiae defective in translation termination and in GTPase activity still supports cell viability

    Directory of Open Access Journals (Sweden)

    Gillet Sylvie

    2008-02-01

    Full Text Available Abstract Background When a stop codon is located in the ribosomal A-site, the termination complex promotes release of the polypeptide and dissociation of the 80S ribosome. In eukaryotes two proteins eRF1 and eRF3 play a crucial function in the termination process. The essential GTPase Sup35p, the eRF3 release factor of Saccharomyces cerevisiae is highly conserved. In particular, we observed that all eRF3 homologs share a potential phosphorylation site at threonine 341, suggesting a functional role for this residue. The goal of this study was to determine whether this residue is actually phosphorylated in yeast and if it is involved in the termination activity of the protein. Results We detected no phosphorylation of the Sup35 protein in vivo. However, we show that it is phosphorylated by the cAMP-dependent protein kinase A on T341 in vitro. T341 was mutated to either alanine or to aspartic acid to assess the role of this residue in the activity of the protein. Both mutant proteins showed a large decrease of GTPase activity and a reduced interaction with eRF1/Sup45p. This was correlated with an increase of translational readthrough in cells carrying the mutant alleles. We also show that this residue is involved in functional interaction between the N- and C-domains of the protein. Conclusion Our results point to a new critical residue involved in the translation termination activity of Sup35 and in functional interaction between the N- and C-domains of the protein. They also raise interesting questions about the relation between GTPase activity of Sup35 and its essential function in yeast.

  2. Wettability influences cell behavior on superhydrophobic surfaces with different topographies

    OpenAIRE

    Lourenco, B.N.; Marchioli, G.; Song, W.; Reis, R.L.; Blitterswijk, van, C.A.; Karperien, H.B.J.; Apeldoorn, van, D.F.; Mano, J.F

    2012-01-01

    Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of polystyrene and poly(l-lactic acid) with different micro/nanotopo...

  3. 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...... 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....

  4. Chemistry and material science at the cell surface

    OpenAIRE

    Weian Zhao; Grace Sock Leng Teo; Namit Kumar; Karp, Jeffrey M.

    2010-01-01

    Cell surfaces are fertile ground for chemists and material scientists to manipulate or augment cell functions and phenotypes. This not only helps to answer basic biology questions but also has diagnostic and therapeutic applications. In this review, we summarize the most recent advances in the engineering of the cell surface. In particular, we focus on the potential applications of surface engineered cells for 1) targeting cells to desirable sites in cell therapy, 2) programming assembly of c...

  5. L-Histidine Inhibits Biofilm Formation and FLO11-Associated Phenotypes in Saccharomyces cerevisiae Flor Yeasts

    OpenAIRE

    Marc Bou Zeidan; Giacomo Zara; Carlo Viti; Francesca Decorosi; Ilaria Mannazzu; Marilena Budroni; Luciana Giovannetti; Severino Zara

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of FLO11 which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling FLO11 alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce FLO11p. The flor strains generally metabolized amino acids and ...

  6. L-Histidine Inhibits Biofilm Formation and FLO11-Associated Phenotypes in Saccharomyces cerevisiae Flor Yeasts

    OpenAIRE

    Marc Bou Zeidan; Giacomo Zara; Carlo Viti; Francesca Decorosi; Ilaria Mannazzu; Marilena Budroni; Luciana Giovannetti; Severino Zara

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of Flo11p which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling Flo11p alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce Flo11p. The flor strains generally metabolized amino acids and dipeptides...

  7. CZTSSe thin film solar cells: Surface treatments

    Science.gov (United States)

    Joglekar, Chinmay Sunil

    Chalcopyrite semiconducting materials, specifically CZTS, are a promising alternative to traditional silicon solar cell technology. Because of the high absorption coefficient; films of the order of 1 micrometer thickness are sufficient for the fabrication of solar cells. Liquid based synthesis methods are advantageous because they are easily scalable using the roll to roll manufacturing techniques. Various treatments are explored in this study to enhance the performance of the selenized CZTS film based solar cells. Thiourea can be used as a sulfur source and can be used to tune band gap of CZTSSe. Bromine etching can be used to manipulate the thickness of sintered CZTSSe film. The etching treatment creates recombination centers which lead to poor device performance. Various after treatments were used to improve the performance of the devices. It was observed that the performance of the solar cell devices could not be improved by any of the after treatment steps. Other surface treatment processes are explored including KCN etching and gaseous H2S treatments. Hybrid solar cells which included use of CIGS nanoparticles at the interface between CZTSSe and CdS are also explored.

  8. High-Throughput Live-Cell Microscopy Analysis of Association Between Chromosome Domains and the Nucleolus in S. cerevisiae.

    Science.gov (United States)

    Wang, Renjie; Normand, Christophe; Gadal, Olivier

    2016-01-01

    Spatial organization of the genome has important impacts on all aspects of chromosome biology, including transcription, replication, and DNA repair. Frequent interactions of some chromosome domains with specific nuclear compartments, such as the nucleolus, are now well documented using genome-scale methods. However, direct measurement of distance and interaction frequency between loci requires microscopic observation of specific genomic domains and the nucleolus, followed by image analysis to allow quantification. The fluorescent repressor operator system (FROS) is an invaluable method to fluorescently tag DNA sequences and investigate chromosome position and dynamics in living cells. This chapter describes a combination of methods to define motion and region of confinement of a locus relative to the nucleolus in cell's nucleus, from fluorescence acquisition to automated image analysis using two dedicated pipelines. PMID:27576709

  9. Cell ATP level of Saccharomyces cerevisiae sensitively responds to culture growth and drug-inflicted variations in membrane integrity and PDR pump activity

    Czech Academy of Sciences Publication Activity Database

    Krasowska, A.; Lukaszewicz, M.; Bartosiewicz, D.; Sigler, Karel

    2010-01-01

    Roč. 395, č. 1 (2010), s. 51-55. ISSN 0006-291X R&D Projects: GA MŠk 1M0570 Institutional research plan: CEZ:AV0Z50200510 Keywords : S. cerevisiae * ABC transporters * ATP level Subject RIV: EE - Microbiology, Virology Impact factor: 2.595, year: 2010

  10. Chemical modulation of the ultra-weak photon emission from Saccharomyces cerevisiae and differentiated HL-60 cells

    OpenAIRE

    Červinková, K. (Kateřina); Nerudová, M. (Michaela); Hašek, J.; Cifra, M

    2015-01-01

    The ultra-weak photon emission (UPE) is a universal phenomenon common to all cells with active oxidative metabolism. Generally accepted mechanism of the origin of the ultra-weak photon emission considers reactions of radical or nonradical reactive oxygen species (ROS) with biomolecules such as lipids and proteins which lead to the formation of electron excited species. During the transition to the ground state the excess energy is released as a photon with a wavelength in the visible range of...

  11. Frequency Selective Surfaces with Nanoparticles Unit Cell

    Directory of Open Access Journals (Sweden)

    Nga Hung Poon

    2015-09-01

    Full Text Available The frequency selective surface (FSS is a periodic structure with filtering performance for optical and microwave signals. The general periodic arrays made with patterned metallic elements can act as an aperture or patch on a substrate. In this work, two kinds of materials were used to produce unit cells with various patterns. Gold nanoparticles of 25 nm diameter were used to form periodic monolayer arrays by a confined photocatalytic oxidation-based surface modification method. As the other material, silver gel was used to create multiple layers of silver. Due to the ultra-thin nature of the self-assembled gold nanoparticle monolayer, it is very easy to penetrate the FSS with terahertz radiation. However, the isolated silver islands made from silver gel form thicker multiple layers and contribute to much higher reflectance. This work demonstrated that multiple silver layers are more suitable than gold nanoparticles for use in the fabrication of FSS structures.

  12. The effect of cryptolepine on the morphology and survival of Escherichia coli, Candida albicans and Saccharomyces cerevisiae.

    Science.gov (United States)

    Sawer, I K; Berry, M I; Brown, M W; Ford, J L

    1995-09-01

    The antimicrobial activity of the indoloquinoline alkaloid, cryptolepine, isolated from Cryptolepis sanguinolenta (Fam. Periplocaceae) was determined against selected micro-organisms. The minimum inhibitory concentration (MIC) ranges obtained, expressed as microgram ml-1, were: 5-10 for Saccharomyces cerevisiae NCPF 3139; 10-20 for S. cerevisiae NCPF 3178; 20-40 for Escherichia coli NCTC 10418; 40-80 for E. coli NCTC 11560, Candida albicans ATCC 10231 and C. tropicalis NCPF; and 80-160 for C. albicans NCPF 3242 and NCPF 3262. Biocidal effects were noted at concentrations 2-4 times those of the MIC of the alkaloid following challenge with 10(6) cfu ml-1 of micro-organisms. Time-kill studies showed a reduction in viable count from 10(6) to < 10 cfu ml-1 in 4 h in C. albicans ATCC 10231 exposed to 320 micrograms ml-1 of the agent; 3 log cycle reductions were recorded for the 6 h counts of E. coli NCTC 10418 and S. cerevisiae NCPF 3139 exposed to 40 micrograms ml-1 and 160 micrograms ml-1 of the alkaloid respectively. These results were consistent with findings using scanning electron microscopy. Exposure of cells to biocidal concentrations of cryptolepine produced filamentation prior to lysis in E. coli NCTC 10418 and extreme disturbance of surface structure, including partial and total collapse, followed by lysis in C. albicans ATCC 10231 and S. cerevisiae NCPF 3139. PMID:7592125

  13. Wettability influences cell behavior on superhydrophobic surfaces with different topographies

    NARCIS (Netherlands)

    Lourenco, B.N.; Marchioli, G.; Song, W; Reis, R.L.; Blitterswijk, van C.A.; Karperien, H.B.J.; Apeldoorn, van A.A.; Mano, J.F.

    2012-01-01

    Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavi

  14. TOTAL ANTIOXIDANT ACTIVITY OF YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2013-02-01

    Full Text Available Antioxidants are health beneficial compounds that can protect cells and macromolecules (e.g. fats, lipids, proteins and DNA from the damage of reactive oxygen species (ROS. Sacchamomyces cerevisiae are know as organisms with very important antioxidative enzyme systems such as superoxide dismutase or catalase. The total antioxidant activity (mmol Trolox equivalent – TE.g-1 d.w. of Saccharomyces cerevisiae was measured by 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid during the yeast cultivation. It was found that the total antioxidant activity was the highest (1.08 mmol TE.g-1 d.w. in the strain Kolín after 32 hours of cultivation and the lowest (0.26 mmol TE.g-1 d.w. in the strain Gyöng after 12 hours of cultivation.

  15. Chemistry and material science at the cell surface

    Directory of Open Access Journals (Sweden)

    Weian Zhao

    2010-04-01

    Full Text Available Cell surfaces are fertile ground for chemists and material scientists to manipulate or augment cell functions and phenotypes. This not only helps to answer basic biology questions but also has diagnostic and therapeutic applications. In this review, we summarize the most recent advances in the engineering of the cell surface. In particular, we focus on the potential applications of surface engineered cells for 1 targeting cells to desirable sites in cell therapy, 2 programming assembly of cells for tissue engineering, 3 bioimaging and sensing, and ultimately 4 manipulating cell biology.

  16. Calculation of cell volumes and surface areas in MCNP

    International Nuclear Information System (INIS)

    MCNP is a general Monte Carlo neutron-photon particle transport code which treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces, and some special fourth-degree surfaces. It is necessary to calculate cell volumes and surface areas so that cell masses, fluxes, and other important information can be determined. The volume/area calculation in MCNP computes cell volumes and surface areas for cells and surfaces rotationally symmetric about any arbitrary axis. 5 figures, 1 table

  17. Critical analysis of the maximum non inhibitory concentration (MNIC) method in quantifying sub-lethal injury in Saccharomyces cerevisiae cells exposed to either thermal or pulsed electric field treatments.

    Science.gov (United States)

    Kethireddy, V; Oey, I; Jowett, Tim; Bremer, P

    2016-09-16

    Sub-lethal injury within a microbial population, due to processing treatments or environmental stress, is often assessed as the difference in the number of cells recovered on non-selective media compared to numbers recovered on a "selective media" containing a predetermined maximum non-inhibitory concentration (MNIC) of a selective agent. However, as knowledge of cell metabolic response to injury, population diversity and dynamics increased, the rationale behind the conventional approach of quantifying sub-lethal injury must be scrutinized further. This study reassessed the methodology used to quantify sub-lethal injury for Saccharomyces cerevisiae cells (≈ 4.75 Log CFU/mL) exposed to either a mild thermal (45°C for 0, 10 and 20min) or a mild pulsed electric field treatment (field strengths of 8.0-9.0kV/cm and energy levels of 8, 14 and 21kJ/kg). Treated cells were plated onto either Yeast Malt agar (YM) or YM containing NaCl, as a selective agent at 5-15% in 1% increments. The impact of sub-lethal stress due to initial processing, the stress due to selective agents in the plating media, and the subsequent variation of inhibition following the treatments was assessed based on the CFU count (cell numbers). ANOVA and a generalised least squares model indicated significant effects of media, treatments, and their interaction effects (Pculture conditions impact on sub-lethal injury. Interestingly for S. cerevisiae cells the number of cells recovered at different NaCl concentrations in the media appears to provide valuable information about the mode of injury, the comparative efficacy of different processing regimes and the inherent degree of resistance within a population. This approach may provide similar information for other micro-organisms. PMID:27343426

  18. Functional and Physical Interactions among Saccharomyces cerevisiae α-Factor Receptors

    OpenAIRE

    Gehret, Austin U.; Connelly, Sara M.; Dumont, Mark E.

    2012-01-01

    The α-factor receptor Ste2p is a G protein-coupled receptor (GPCR) expressed on the surface of MATa haploid cells of the yeast Saccharomyces cerevisiae. Binding of α-factor to Ste2p results in activation of a heterotrimeric G protein and of the pheromone response pathway. Functional interactions between α-factor receptors, such as dominant-negative effects and recessive behavior of constitutive and hypersensitive mutant receptors, have been reported previously. We show here that dominant-nega...

  19. Optimization of permeabilization process of yeast cells for catalase activity using response surface methodology

    OpenAIRE

    Trawczyńska, Ilona; Wójcik, Marek

    2015-01-01

    Biotransformation processes accompanied by whole yeast cells as biocatalyst are a promising area of food industry. Among the chemical sanitizers currently used in food technology, hydrogen peroxide is a very effective microbicidal and bleaching agent. In this paper, permeabilization has been applied to Saccharomyces cerevisiae yeast cells aiming at increased intracellular catalase activity for decomposed H2O2. Ethanol, which is non-toxic, biodegradable and easily available, has been used as p...

  20. Profiling of the toxicity mechanisms of coated and uncoated silver nanoparticles to yeast Saccharomyces cerevisiae BY4741 using a set of its 9 single-gene deletion mutants defective in oxidative stress response, cell wall or membrane integrity and endocytosis.

    Science.gov (United States)

    Käosaar, Sandra; Kahru, Anne; Mantecca, Paride; Kasemets, Kaja

    2016-09-01

    The widespread use of nanosilver in various antibacterial, antifungal, and antiviral products warrants the studies of the toxicity pathways of nanosilver-enabled materials toward microbes and viruses. We profiled the toxicity mechanisms of uncoated, casein-coated, and polyvinylpyrrolidone-coated silver nanoparticles (AgNPs) using Saccharomyces cerevisiae wild-type (wt) and its 9 single-gene deletion mutants defective in oxidative stress (OS) defense, cell wall/membrane integrity, and endocytosis. The 48-h growth inhibition assay in organic-rich growth medium and 24-h cell viability assay in deionized (DI) water were applied whereas AgNO3, H2O2, and SDS served as positive controls. Both coated AgNPs (primary size 8-12nm) were significantly more toxic than the uncoated (~85nm) AgNPs. All studied AgNPs were ~30 times more toxic if exposed to yeast cells in DI water than in the rich growth medium: the IC50 based on nominal concentration of AgNPs in the growth inhibition test ranged from 77 to 576mg Ag/L and in the cell viability test from 2.7 to 18.7mg Ag/L, respectively. Confocal microscopy showed that wt but not endocytosis mutant (end3Δ) internalized AgNPs. Comparison of toxicity patterns of wt and mutant strains defective in OS defense and membrane integrity revealed that the toxicity of the studied AgNPs to S. cerevisiae was not caused by the OS or cell wall/membrane permeabilization. PMID:27260961

  1. Basic surface properties of mononuclear cells from Didelphis marsupialis.

    Science.gov (United States)

    Nacife, V P; de Meirelles, M de N; Silva Filho, F C

    1998-01-01

    The electrostatic surface charge and surface tension of mononuclear cells/monocytes obtained from young and adult marsupials (Didelphis marsupialis) were investigated by using cationized ferritin and colloidal iron hydroxyde, whole cell electrophoresis, and measurements of contact angles. Anionic sites were found distributed throughout the entire investigated cell surfaces. The results revealed that the anionic character of the cells is given by electrostatic charges corresponding to -18.8 mV (cells from young animals) and -29.3 mV (cells from adult animals). The surface electrostatic charge decreased from 10 to 65.2% after treatment of the cells with each one of trypsin, neuraminidase and phospholipase C. The hydrophobic nature of the mononuclear cell surfaces studied by using the contact angle method revealed that both young and adult cells possess cell surfaces of high hidrofilicity since the angles formed with drops of saline water were 42.5 degrees and 40.8 degrees, respectively. Treatment of the cells with trypsin or neuraminidase rendered their surfaces more hydrophobic, suggesting that sialic acid-containing glycoproteins are responsible for most of the hydrophilicity observed in the mononuclear cell surfaces from D. marsupialis. PMID:9921307

  2. Basic Surface Properties of Mononuclear Cells from Didelphis marsupialis

    Directory of Open Access Journals (Sweden)

    Nacife Valéria Pereira

    1998-01-01

    Full Text Available The electrostatic surface charge and surface tension of mononuclear cells/monocytes obtained from young and adult marsupials (Didelphis marsupialis were investigated by using cationized ferritin and colloidal iron hydroxyde, whole cell electrophoresis, and measurements of contact angles. Anionic sites were found distributed throughout the entire investigated cell surfaces. The results revealed that the anionic character of the cells is given by electrostatic charges corresponding to -18.8 mV (cells from young animals and -29.3 mV (cells from adult animals. The surface electrostatic charge decreased from 10 to 65.2% after treatment of the cells with each one of trypsin, neuraminidase and phospholipase C. The hydrophobic nature of the mononuclear cell surfaces studied by using the contact angle method revealed that both young and adult cells possess cell surfaces of high hidrofilicity since the angles formed with drops of saline water were 42.5°and 40.8°, respectively. Treatment of the cells with trypsin or neuraminidase rendered their surfaces more hydrophobic, suggesting that sialic acid-containing glycoproteins are responsible for most of the hydrophilicity observed in the mononuclear cell surfaces from D. marsupialis.

  3. Nanofabrication of Nonfouling Surfaces for Micropatterning of Cell and Microtissue

    Directory of Open Access Journals (Sweden)

    Hidenori Otsuka

    2010-08-01

    Full Text Available Surface engineering techniques for cellular micropatterning are emerging as important tools to clarify the effects of the microenvironment on cellular behavior, as cells usually integrate and respond the microscale environment, such as chemical and mechanical properties of the surrounding fluid and extracellular matrix, soluble protein factors, small signal molecules, and contacts with neighboring cells. Furthermore, recent progress in cellular micropatterning has contributed to the development of cell-based biosensors for the functional characterization and detection of drugs, pathogens, toxicants, and odorants. In this regards, the ability to control shape and spreading of attached cells and cell-cell contacts through the form and dimension of the cell-adhesive patches with high precision is important. Commitment of stem cells to different specific lineages depends strongly on cell shape, implying that controlled microenvironments through engineered surfaces may not only be a valuable approach towards fundamental cell-biological studies, but also of great importance for the design of cell culture substrates for tissue engineering. To develop this kind of cellular microarray composed of a cell-resistant surface and cell attachment region, micropatterning a protein-repellent surface is important because cellular adhesion and proliferation are regulated by protein adsorption. The focus of this review is on the surface engineering aspects of biologically motivated micropatterning of two-dimensional surfaces with the aim to provide an introductory overview described in the literature. In particular, the importance of non-fouling surface chemistries is discussed.

  4. Osteoblast cell response to surface-modified carbon nanotubes

    International Nuclear Information System (INIS)

    In order to investigate the interaction of cells with modified multi-walled carbon nanotubes (MWCNTs) for their potential biomedical applications, the MWCNTs were chemically modified with carboxylic acid groups (–COOH), polyvinyl alcohol (PVA) polymer and biomimetic apatite on their surfaces. Additionally, human osteoblast MG-63 cells were cultured in the presence of the surface-modified MWCNTs. The metabolic activities of osteoblastic cells, cell proliferation properties, as well as cell morphology were studied. The surface modification of MWCNTs with biomimetic apatite exhibited a significant increase in the cell viability of osteoblasts, up to 67.23%. In the proliferation phases, there were many more cells in the biomimetic apatite-modified MWCNT samples than in the MWCNTs–COOH. There were no obvious changes in cell morphology in osteoblastic MG-63 cells cultured in the presence of these chemically-modified MWCNTs. The surface modification of MWCNTs with apatite achieves an effective enhancement of their biocompatibility.

  5. Surface cell differentiation controls tissue surface tension and tissue positioning during zebrafish gastrulation

    Science.gov (United States)

    Krens, S. F. G.

    2011-03-01

    Differences in tissue surface tension (TST) between different tissue types are thought to guide tissue organization and cell sorting in development. Measurements of TST have been useful to predict the outcome of in vitro cell sorting and envelopment experiments. However, the outcome of cell sorting experiments in vitro often substantially differs from tissue positioning in vivo, raising questions as to the actual contribution of TST to tissue positioning within the developing embryo. Here, we show that surface tension of germ layer tissues during zebrafish gastrulation critically relies on the differentiation of their surface cells. We also show that surface differentiation of the different germ layer tissues varies and is considerably different between the situation in vitro and in vivo, explaining the apparent dissimilar outcome of cell segregation between these two situations. To analyze germ layer TST as a function of surface cell differentiation, we interfere with surface cell properties of germ layer aggregates by misexpressing genes involved in surface cell differentiation specifically within surface cells using the GAL4-UAS system, and measure tissue surface tension using both parallel plate compression and micropipette aspiration techniques. Our data provides evidence in favor of a critical function of surface cell differentiation in modulating TST and subsequently tissue positioning within the developing embryo.

  6. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production.

    Science.gov (United States)

    Liu, Zhuo; Ho, Shih-Hsin; Sasaki, Kengo; den Haan, Riaan; Inokuma, Kentaro; Ogino, Chiaki; van Zyl, Willem H; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell surface. The cellulase-displaying yeast strain exhibited clear cell-to-cellulose adhesion and a "tearing" cellulose degradation pattern; the adhesion ability correlated with enhanced surface area and roughness of the target cellulose fibers, resulting in higher hydrolysis efficiency. The engineered yeast directly produced ethanol from rice straw despite a more than 40% decrease in the required enzyme dosage for high-density fermentation. Thus, improved cell-to-cellulose interactions provided a novel strategy for increasing cellulose hydrolysis, suggesting a mechanism for promoting the feasibility of cellulosic biofuel production. PMID:27079382

  7. Toward Cell Selective Surfaces: Cell Adhesion and Proliferation on Breath Figures with Antifouling Surface Chemistry.

    Science.gov (United States)

    Martínez-Campos, Enrique; Elzein, Tamara; Bejjani, Alice; García-Granda, Maria Jesús; Santos-Coquillat, Ana; Ramos, Viviana; Muñoz-Bonilla, Alexandra; Rodríguez-Hernández, Juan

    2016-03-16

    We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties. PMID:26909529

  8. SACCHAROMYCES CEREVISIAE AND ITS VALIDATION

    Directory of Open Access Journals (Sweden)

    Miroslav Ondrejovič

    2015-02-01

    Full Text Available The aim of this study was to optimize of independent variables as temperature, time and reaction ratio to output parameter of simultaneous enzyme saccharification and fermentation by Saccharomyces cerevisiae of pretreated wheat straw as model substrate via RSM (response surface methodology approach. As dependent variable, it was chosen ethanol yields characterizing effectivity of process. The optimal conditions were approximately temperature 100 °C, time 1 hour and reaction ratio 26 mL to 1 g of treated wheat straw with ethanol yields 141.9 mg.g-1. After calculating the optimal values, the validation analyze was carried out and it was found out that the predicted and experimentally verified dependent variable was in agreement with the optimal parameters (~ 95 %. Proposed model was tested for three lignocellulosic materials (winter wheat straw, alfalfa hay and maize straw as wheat straw used as model substrate and it was confirmed the possibility of its use for other agricultural residues with similar content of lignocellulose.

  9. The Unfolded Protein Response Is Induced by the Cell Wall Integrity Mitogen-activated Protein Kinase Signaling Cascade and Is Required for Cell Wall Integrity in Saccharomyces cerevisiae

    OpenAIRE

    Scrimale, Thomas; DiDone, Louis; de Mesy Bentley, Karen L.; Krysan, Damian J.

    2009-01-01

    The yeast cell wall is an extracellular structure that is dependent on secretory and membrane proteins for its construction. We investigated the role of protein quality control mechanisms in cell wall integrity and found that the unfolded protein response (UPR) and, to a lesser extent, endoplasmic reticulum (ER)-associated degradation (ERAD) pathways are required for proper cell wall construction. Null mutation of IRE1, double mutation of ERAD components (hrd1Δ and ubc7Δ) and ire1Δ, or expres...

  10. Melittin interaction with sulfated cell surface sugars.

    Science.gov (United States)

    Klocek, Gabriela; Seelig, Joachim

    2008-03-01

    Melittin is a 26-residue cationic peptide with cytolytic and antimicrobial properties. Studies on the action mechanism of melittin have focused almost exclusively on the membrane-perturbing properties of this peptide, investigating in detail the melittin-lipid interaction. Here, we report physical-chemical studies on an alternative mechanism by which melittin could interact with the cell membrane. As the outer surface of many cells is decorated with anionic (sulfated) glycosaminoglycans (GAGs), a strong Coulombic interaction between the two oppositely charged molecules can be envisaged. Indeed, the present study using isothermal titration calorimetry reveals a high affinity of melittin for several GAGs, that is, heparan sulfate (HS), dermatan sulfate, and heparin. The microscopic binding constant of melittin for HS is 2.4 x 10 (5) M (-1), the reaction enthalpy is Delta H melittin (0) = -1.50 kcal/mol, and the peptide-to-HS stoichiometry is approximately 11 at 10 mM Tris, 100 mM NaCl at pH 7.4 and 28 degrees C. Delta H melittin (0) is characterized by a molar heat capacity of Delta C P (0) = -227 cal mol (-1) K (-1). The large negative heat capacity change indicates that hydrophobic interactions must also be involved in the binding of melittin to HS. Circular dichroism spectroscopy demonstrates that the binding of the peptide to HS induces a conformational change to a predominantly alpha-helical structure. A model for the melittin-HS complex is presented. Melittin binding was compared with that of magainin 2 and nisin Z to HS. Magainin 2 is known for its antimicrobial properties, but it does not cause lysis of the eukaryotic cells. Nisin Z shows activity against various Gram-positive bacteria. Isothermal titration calorimetry demonstrates that magainin 2 and nisin Z do not bind to HS (5-50 degrees C, 10 mM Tris, and 100 mM NaCl at pH 7.4). PMID:18220363

  11. Studies of cell biomechanics with surface micro-/nano-technology

    International Nuclear Information System (INIS)

    We report the recent progress in our studies of cell biology using micro-/nano-technology. Cells have a size of several to tens of microns, which makes them easily manipulated by micro-/nano-technology. The shape of the cell influences the alignment of the actin cytoskeleton, which bears the main forces of the cell, maintains the shape,and mediates a series of biochemical reactions. We invented a stretching device and studied the real-time actin filament dynamics under stretch. We found that one stretch cycle shortened the actin filaments and promoted their reassemble process. Cell migration is a complex mechanical process. We found that cell geometry determines the cell polarity and migration direction. We fabricated three-dimensional surfaces to mimic the topography in vivo, and further built a cell culture model by integrating the three-dimensional surface, microfluidics, cell patterning,and coculturing of multiple cell types. We also investigated the neuronal guidance by surface patterning. (authors)

  12. Dendritic Cell Responses to Surface Properties of Clinical Titanium Surfaces

    OpenAIRE

    Kou, Peng Meng; Schwartz, Zvi; Boyan, Barbara D; Babensee, Julia E.

    2010-01-01

    Dendritic cells (DCs) play pivotal roles in responding to foreign entities during an innate immune response and initiating effective adaptive immunity as well as maintaining immune tolerance. The sensitivity of DCs to foreign stimuli also makes them useful cells to assess the inflammatory response to biomaterials. Elucidating the material property-DC phenotype relationships using a well-defined biomaterial system is expected to provide criteria for immuno-modulatory biomaterial design. Clinic...

  13. Calreticulin: Roles in Cell-Surface Protein Expression

    Directory of Open Access Journals (Sweden)

    Yue Jiang

    2014-09-01

    Full Text Available In order to perform their designated functions, proteins require precise subcellular localizations. For cell-surface proteins, such as receptors and channels, they are able to transduce signals only when properly targeted to the cell membrane. Calreticulin is a multi-functional chaperone protein involved in protein folding, maturation, and trafficking. However, evidence has been accumulating that calreticulin can also negatively regulate the surface expression of certain receptors and channels. In these instances, depletion of calreticulin enhances cell-surface expression and function. In this review, we discuss the role of calreticulin with a focus on its negative effects on the expression of cell-surface proteins.

  14. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes.

    Science.gov (United States)

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  15. Targeting Negative Surface Charges of Cancer Cells by Multifunctional Nanoprobes

    Science.gov (United States)

    Chen, Bingdi; Le, Wenjun; Wang, Yilong; Li, Zhuoquan; Wang, Dong; Ren, Lei; Lin, Ling; Cui, Shaobin; Hu, Jennifer J.; Hu, Yihui; Yang, Pengyuan; Ewing, Rodney C.; Shi, Donglu; Cui, Zheng

    2016-01-01

    A set of electrostatically charged, fluorescent, and superparamagnetic nanoprobes was developed for targeting cancer cells without using any molecular biomarkers. The surface electrostatic properties of the established cancer cell lines and primary normal cells were characterized by using these nanoprobes with various electrostatic signs and amplitudes. All twenty two randomly selected cancer cell lines of different organs, but not normal control cells, bound specifically to the positively charged nanoprobes. The relative surface charges of cancer cells could be quantified by the percentage of cells captured magnetically. The activities of glucose metabolism had a profound impact on the surface charge level of cancer cells. The data indicate that an elevated glycolysis in the cancer cells led to a higher level secretion of lactate. The secreted lactate anions are known to remove the positive ions, leaving behind the negative changes on the cell surfaces. This unique metabolic behavior is responsible for generating negative cancer surface charges in a perpetuating fashion. The metabolically active cancer cells are shown to a unique surface electrostatic pattern that can be used for recovering cancer cells from the circulating blood and other solutions. PMID:27570558

  16. Metabolic alterations during ascosporogenesis of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Sporulation of S. cerevisiae has been shown to alter the profiles of enzymes involved in gluconeogenesis and glycolysis. The enhancement in the levels of total cellular carbohydrates could be correlated with the enhancement in fructose 1,6-diphosphatase and trehalose-phosphate synthetase. The latter activity could account for the 15-fold increase in trehalose levels in sporulating cells. Glucose-6-phosphatase, pyruvate kinase and phosphofructokinase showed continuous decline during ascosporogenesis. The relative incorporation of radioactivity from possible precursors of gluconeogenesis indicated that acetate-2-14C alone could contribute to carbohydrate synthesis. (author)

  17. Removing cadmium from electroplating wastewater by waste saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    DAI Shu-juan; WEI De-zhou; ZHOU Dong-qin; JIA Chun-yun; WANG Yu-juan; LIU Wen-gang

    2008-01-01

    The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.

  18. How cells tiptoe on adhesive surfaces before sticking

    CERN Document Server

    Pierres, Anne; Touchard, Dominique; Bongrand, Pierre

    2008-01-01

    Cell membranes are studded with protrusions that were thoroughly analyzed with electron microscopy. However, the nanometer-scale three-dimensional motions generated by cell membranes to fit the topography of foreign surfaces and initiate adhesion remain poorly understood. Here, we describe the dynamics of surface deformations displayed by monocytic cells bumping against fibronectin-coated surfaces. We observed membrane undulations with typically 5 nm amplitude and 5-10 second lifetime. Cell membranes behaved as independent units of micrometer size. Cells detected the presence of foreign surfaces at 50 nm separation, resulting in time-dependent amplification of membrane undulations. Molecular contact then ensued with apparent cell-membrane separation of 30-40 nm, and this distance steadily decreased during the following tens of seconds. Contact maturation was associated with in-plane egress of bulky molecules and robust membrane fluctuations. Thus, membrane undulations may be the major determinant of cell sens...

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

    International Nuclear Information System (INIS)

    Authors have reported preconcentration of 152Eu, 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

  20. Soluble and cell surface receptors for tumor necrosis factor

    DEFF Research Database (Denmark)

    Wallach, D; Engelmann, H; Nophar, Y;

    1991-01-01

    Tumor necrosis factor (TNF) initiates its multiple effects on cell function by binding at a high affinity to specific cell surface receptors. Two different molecular species of these receptors, which are expressed differentially in different cells, have been identified. The cDNAs of both receptors...... certain pathological situations. Release of the soluble receptors from the cells seems to occur by proteolytic cleavage of the cell surface forms and appears to be a way of down-regulating the cell response to TNF. Because of their ability to bind TNF, the soluble receptors exert an inhibitory effect on...

  1. 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...

  2. Oral administration of myostatin-specific recombinant Saccharomyces cerevisiae vaccine in rabbit.

    Science.gov (United States)

    Liu, Zhongtian; Zhou, Gang; Ren, Chonghua; Xu, Kun; Yan, Qiang; Li, Xinyi; Zhang, Tingting; Zhang, Zhiying

    2016-04-29

    Yeast is considered as a simple and cost-effective host for protein expression, and our previous studies have proved that Saccharomyces cerevisiae can deliver recombinant protein and DNA into mouse dendritic cells and can further induce immune responses as novel vaccines. In order to know whether similar immune responses can be induced in rabbit by oral administration of such recombinant S. cerevisiae vaccine, we orally fed the rabbits with heat-inactivated myostatin-recombinant S. cerevisiae for 5 weeks, and then myostatin-specific antibody in serum was detected successfully by western blotting and ELISA assay. The rabbits treated with myostatin-recombinant S. cerevisiae vaccine grew faster and their muscles were much heavier than that of the control group. As a common experimental animal and a meat livestock with great economic value, rabbit was proved to be the second animal species that have been successfully orally immunized by recombinant S. cerevisiae vaccine after mice. PMID:27005809

  3. 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…

  4. Investigation of back surface fields effect on bifacial solar cells

    Science.gov (United States)

    Sepeai, Suhaila; Sulaiman, M. Y.; Sopian, Kamaruzzaman; Zaidi, Saleem H.

    2012-11-01

    A bifacial solar cell, in contrast with a conventional monofacial solar cell, produces photo-generated current from both front and back sides. Bifacial solar cell is an attractive candidate for enhancing photovoltaic (PV) market competitiveness as well as supporting the current efforts to increase efficiency and lower material costs. This paper reports on the fabrication of bifacial solar cells using phosphorus-oxytrichloride (POCl3) emitter formation on p-type, nanotextured silicon (Si) wafer. Backside surface field was formed through Al-diffusion using conventional screen-printing process. Bifacial solar cells with a structure of n+pp+ with and without back surface field (BSF) were fabricated in which silicon nitride (SiN) anti reflection and passivation films were coated on both sides, followed by screen printing of Argentum (Ag) and Argentum/Aluminum (Ag/Al) on front and back contacts, respectively. Bifacial solar cells without BSF exhibited open circuit voltage (VOC) of 535 mV for front and 480 mV for back surface. With Al-alloyed BSF bifacial solar cells, the VOC improved to 580 mV for the front surface and 560 mV for the back surface. Simulation of bifacial solar cells using PC1D and AFORS software demonstrated good agreement with experimental results. Simulations showed that best bifacial solar cells are achieved through a combination of high lifetime wafer, low recombination back surface field, reduced contact resistance, and superior surface passivation.

  5. The Interaction between Saccharomyces cerevisiae and Non-Saccharomyces Yeast during Alcoholic Fermentation Is Species and Strain Specific.

    Science.gov (United States)

    Wang, Chunxiao; Mas, Albert; Esteve-Zarzoso, Braulio

    2016-01-01

    The present study analyzes the lack of culturability of different non-Saccharomyces strains due to interaction with Saccharomyces cerevisiae during alcoholic fermentation. Interaction was followed in mixed fermentations with 1:1 inoculation of S. cerevisiae and ten non-Saccharomyces strains. Starmerella bacillaris, and Torulaspora delbrueckii indicated longer coexistence in mixed fermentations compared with Hanseniaspora uvarum and Metschnikowia pulcherrima. Strain differences in culturability and nutrient consumption (glucose, alanine, ammonium, arginine, or glutamine) were found within each species in mixed fermentation with S. cerevisiae. The interaction was further analyzed using cell-free supernatant from S. cerevisiae and synthetic media mimicking both single fermentations with S. cerevisiae and using mixed fermentations with the corresponding non-Saccharomyces species. Cell-free S. cerevisiae supernatants induced faster culturability loss than synthetic media corresponding to the same fermentation stage. This demonstrated that some metabolites produced by S. cerevisiae played the main role in the decreased culturability of the other non-Saccharomyces yeasts. However, changes in the concentrations of main metabolites had also an effect. Culturability differences were observed among species and strains in culture assays and thus showed distinct tolerance to S. cerevisiae metabolites and fermentation environment. Viability kit and recovery analyses on non-culturable cells verified the existence of viable but not-culturable status. These findings are discussed in the context of interaction between non-Saccharomyces and S. cerevisiae. PMID:27148191

  6. Flavour compound production by Yarrowia lipolytica, Saccharomyces cerevisiae and Debaryomyces hansenii in a cheese-surface model

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Gori, Klaus; Petersen, Mikael Agerlin; Jespersen, Lene; Arneborg, Nils

    2011-01-01

    A simple cheese model mimicking a cheese surface was developed for the detection of cheese flavour formation of yeasts. A total of 56 flavour compounds were detected by dynamic headspace sampling followed by gas chromatography - mass spectrometry analysis. Yarrowia lipolytica CBS2075 primarily...

  7. FABRICATION AND BIOCOMPATIBILITY OF CELL OUTER MEMBRANE MIMETIC SURFACES

    Institute of Scientific and Technical Information of China (English)

    Ming-ming Zong; Yong-kuan Gong

    2011-01-01

    The surface design used for improving biocompatibility is one of the most important issues for the fabrication of medical devices. For mimicking the ideal surface structure of cell outer membrane, a large number of polymers bearing phosphorylcholine (PC) groups have been employed to modify the surfaces of biomaterials and medical devices. It has been demonstrated that the biocompatibility of the modified materials whose surface is required to interact with a living organism has been obviously improved by introducing PC groups. In this review, the fabrication strategies of cell outer membrane mimetic surfaces and their resulted biocompatibilities were summarized.

  8. Cell surface hydrophobicity of dental plaque microorganisms in situ.

    OpenAIRE

    Rosenberg, M.; Judes, H; Weiss, E

    1983-01-01

    The cell surface hydrophobicity of bacteria obtained directly from human tooth surfaces was assayed by measuring their adherence to liquid hydrocarbons. Fresh samples of supragingival dental plaque were washed and dispersed in buffer. Adherence of the plaque microorganisms to hexadecane, octane, and xylene was tested turbidimetrically and by direct microscopic observation. The results clearly show that the vast majority of bacteria comprising dental plaque exhibit pronounced cell surface hydr...

  9. Microplicae: specialized surface structure of epithelial cells of wet-surfaced oral mucosa

    NARCIS (Netherlands)

    P. Asikainen; E. Sirviö; J.J.W. Mikkonen; S.P. Singh; E.A.J.M. Schulten; C.M. ten Bruggenkate; A.P. Koistinen; A.M. Kullaa

    2015-01-01

    The surface structure of the superficial cells of the oral mucosa is decorated with numerous membrane ridges, termed microplicae (MPLs). The MPL structure is typical of the epithelial surfaces that are covered with protective mucus. Cell membrane MPLs are no longer seen as passive consequences of ce

  10. Glucose induces rapid changes in the secretome of Saccharomyces cerevisiae

    OpenAIRE

    Giardina, Bennett J.; Stanley, Bruce A.; Chiang, Hui-Ling

    2014-01-01

    Background Protein secretion is a fundamental process in all living cells. Proteins can either be secreted via the classical or non-classical pathways. In Saccharomyces cerevisiae, gluconeogenic enzymes are in the extracellular fraction/periplasm when cells are grown in media containing low glucose. Following a transfer of cells to high glucose media, their levels in the extracellular fraction are reduced rapidly. We hypothesized that changes in the secretome were not restricted to gluconeoge...

  11. Temperature-Responsive Polymer Modified Surface for Cell Sheet Engineering

    Directory of Open Access Journals (Sweden)

    Teruo Okano

    2012-08-01

    Full Text Available In the past two decades, as a novel approach for tissue engineering, cell sheet engineering has been proposed by our laboratory. Poly(N-isopropylacrylamide (PIPAAm, which is a well-known temperature-responsive polymer, has been grafted on tissue culture polystyrene (TCPS surfaces through an electron beam irradiated polymerization. At 37 °C, where the PIPAAm modified surface is hydrophobic, cells can adhere, spread on the surface and grow to confluence. By decreasing temperature to 20 °C, since the surface turns to hydrophilic, cells can detach themselves from the surface spontaneously and form an intact cell sheet with extracellular matrix. For obtaining a temperature-induced cell attachment and detachment, it is necessary to immobilize an ultra thin PIPAAm layer on the TCPS surfaces. This review focuses on the characteristics of PIAPAm modified surfaces exhibiting these intelligent properties. In addition, PIPAAm modified surfaces giving a rapid cell-sheet recovery has been further developed on the basis of the characteristic of the PIPAAm surface. The designs of temperature-responsive polymer layer have provided an enormous potential to fabricate clinically applicable regenerative medicine.

  12. Cell Surface Proteome of Dental Pulp Stem Cells Identified by Label-Free Mass Spectrometry

    Science.gov (United States)

    Niehage, Christian; Karbanová, Jana; Steenblock, Charlotte

    2016-01-01

    Multipotent mesenchymal stromal cells (MSCs) are promising tools for regenerative medicine. They can be isolated from different sources based on their plastic-adherence property. The identification of reliable cell surface markers thus becomes the Holy Grail for their prospective isolation. Here, we determine the cell surface proteomes of human dental pulp-derived MSCs isolated from single donors after culture expansion in low (2%) or high (10%) serum-containing media. Cell surface proteins were tagged on intact cells using cell impermeable, cleavable sulfo-NHS-SS-biotin, which allows their enrichment by streptavidin pull-down. For the proteomic analyses, we first compared label-free methods to analyze cell surface proteomes i.e. composition, enrichment and proteomic differences, and we developed a new mathematical model to determine cell surface protein enrichment using a combinatorial gene ontology query. Using this workflow, we identified 101 cluster of differentiation (CD) markers and 286 non-CD cell surface proteins. Based on this proteome profiling, we identified 14 cell surface proteins, which varied consistently in abundance when cells were cultured under low or high serum conditions. Collectively, our analytical methods provide a basis for identifying the cell surface proteome of dental pulp stem cells isolated from single donors and its evolution during culture or differentiation. Our data provide a comprehensive cell surface proteome for the precise identification of dental pulp-derived MSC populations and their isolation for potential therapeutic intervention. PMID:27490675

  13. Cell Surface Proteome of Dental Pulp Stem Cells Identified by Label-Free Mass Spectrometry.

    Science.gov (United States)

    Niehage, Christian; Karbanová, Jana; Steenblock, Charlotte; Corbeil, Denis; Hoflack, Bernard

    2016-01-01

    Multipotent mesenchymal stromal cells (MSCs) are promising tools for regenerative medicine. They can be isolated from different sources based on their plastic-adherence property. The identification of reliable cell surface markers thus becomes the Holy Grail for their prospective isolation. Here, we determine the cell surface proteomes of human dental pulp-derived MSCs isolated from single donors after culture expansion in low (2%) or high (10%) serum-containing media. Cell surface proteins were tagged on intact cells using cell impermeable, cleavable sulfo-NHS-SS-biotin, which allows their enrichment by streptavidin pull-down. For the proteomic analyses, we first compared label-free methods to analyze cell surface proteomes i.e. composition, enrichment and proteomic differences, and we developed a new mathematical model to determine cell surface protein enrichment using a combinatorial gene ontology query. Using this workflow, we identified 101 cluster of differentiation (CD) markers and 286 non-CD cell surface proteins. Based on this proteome profiling, we identified 14 cell surface proteins, which varied consistently in abundance when cells were cultured under low or high serum conditions. Collectively, our analytical methods provide a basis for identifying the cell surface proteome of dental pulp stem cells isolated from single donors and its evolution during culture or differentiation. Our data provide a comprehensive cell surface proteome for the precise identification of dental pulp-derived MSC populations and their isolation for potential therapeutic intervention. PMID:27490675

  14. Smooth Muscle Cell Functionality on Collagen Immobilized Polycaprolactone Nanowire Surfaces

    Directory of Open Access Journals (Sweden)

    Victoria Leszczak

    2014-05-01

    Full Text Available Inhibition of smooth muscle cell (SMC proliferation and preservation of a differentiated state are important aspects in the management, avoidance and progression of vascular diseases. An understanding of the interaction between SMCs and the biomaterial involved is essential for a successful implant. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human aortic SMCs. The nanowire surfaces were fabricated from polycaprolactone and were immobilized with collagen. The objective of this study is to reveal how SMCs interact with collagen immobilized nanostructures. The results indicate significantly higher cellular adhesion on nanostructured and collagen immobilized surfaces; however, SMCs on nanostructured surfaces exhibit a more elongated phenotype. The reduction of MTT was significantly lower on nanowire (NW and collagen immobilized NW (colNW surfaces, suggesting that SMCs on nanostructured surfaces may be differentiated and slowly dividing. Scanning electron microscopy results reveal that SMCs on nanostructured surfaces are more elongated and that cells are interacting with the nano-features on the surface. After providing differentiation cues, heavy chain myosin and calponin, specific to a contractile SMC phenotype, are upregulated on collagen immobilized surfaces. These results suggest that nanotopography affects cell adhesion, proliferation, as well as cell elongation, while collagen immobilized surfaces greatly affect cell differentiation.

  15. Fluid dynamics and noise in bacterial cell-cell and cell-surface scattering

    CERN Document Server

    Drescher, Knut; Cisneros, Luis H; Ganguly, Sujoy; Goldstein, Raymond E; 10.1073/pnas.1019079108

    2011-01-01

    Bacterial processes ranging from gene expression to motility and biofilm formation are constantly challenged by internal and external noise. While the importance of stochastic fluctuations has been appreciated for chemotaxis, it is currently believed that deterministic long-range fluid dynamical effects govern cell-cell and cell-surface scattering - the elementary events that lead to swarming and collective swimming in active suspensions and to the formation of biofilms. Here, we report the first direct measurements of the bacterial flow field generated by individual swimming Escherichia coli both far from and near to a solid surface. These experiments allowed us to examine the relative importance of fluid dynamics and rotational diffusion for bacteria. For cell-cell interactions it is shown that thermal and intrinsic stochasticity drown the effects of long-range fluid dynamics, implying that physical interactions between bacteria are determined by steric collisions and near-field lubrication forces. This dom...

  16. Mitotic Spindle Positioning in Saccharomyces cerevisiae Is Accomplished by Antagonistically Acting Microtubule Motor Proteins

    OpenAIRE

    Cottingham, Frank R.; Hoyt, M. Andrew

    1997-01-01

    Proper positioning of the mitotic spindle is often essential for cell division and differentiation processes. The asymmetric cell division characteristic of budding yeast, Saccharomyces cerevisiae, requires that the spindle be positioned at the mother–bud neck and oriented along the mother–bud axis. The single dynein motor encoded by the S. cerevisiae genome performs an important but nonessential spindle-positioning role. We demonstrate that kinesin-related Kip3p makes a major contribution to...

  17. Identification of a Saccharomyces cerevisiae Glucosidase That Hydrolyzes Flavonoid Glucosides▿ †

    OpenAIRE

    Schmidt, Sabine; Rainieri, Sandra; Witte, Simone; Matern, Ulrich; Martens, Stefan

    2011-01-01

    Baker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-β-glucoside revealed considerable β-glucosidase activity, which impairs any strategy to generate or modify flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in the S. cerevisiae genome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic α- or β-...

  18. 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)

  19. Solitary wave propagation in surface stabilized ferroelectric liquid crystal cells

    OpenAIRE

    VIJ, JAGDISH; Song, Jang-Kun

    2008-01-01

    PUBLISHED Solitary wave propagation in surface stabilized ferroelectric liquid crystal cells controlled by surface anchoring of the alignment layers is investigated for different conditions of alignment on the two opposite surfaces. We show that the critical field Ec, where the speed of the solitary wave becomes zero, is finite for asymmetric alignment on two surfaces. We also show that the polar anchoring energy difference (Deltawp) between the alignment layers can be calculated by measur...

  20. Characteristics of a simple surface textured silicon solar cells

    International Nuclear Information System (INIS)

    The extend of surface availability for light exposure relate to the amount of generated photocarrier in a solar cell. The normal way of increasing the surface area is to increase the size of substrate. In this paper a study was made on the effect of chemical modification on the active surface to the characteristics of the solar cell. Different chemical solutions which are normally available in any laboratory are used. P-type silicon wafer with surface orientation (111) formed the substrate. Aluminium was used as back contact and front grid. No antireflecting coating was introduced. The result indicates that surface textured silicon solar cell give a higher current output as compared to a non texture solar cell. (Author)

  1. Surface passivation of high efficiency silicon solar cells

    Science.gov (United States)

    Aberle, A.; Warta, W.; Knobloch, J.; Voss, B.

    Theoretically and experimentally determined design guides for significantly reducing recombination at the emitter and rear surfaces of full-area Al-BSF (back-surface region) and oxide-passivated bifacial cells are given. The impact of emitter thickness and surface dopant concentration on emitter saturation current and solar cell efficiency is outlined. A modified emitter structure (locally deep diffused below the metal contacts) is predicted to have superior performance. Measured Voc values reveal the potential of deep emitter cells to achieve efficiencies above 20 percent in spite of high metallization factors. Experimentally, a strong dependence of passivation quality on oxide thickness and base doping concentration is found. The BSF quality of a diffused aluminum layer decreases strongly with increasing drive-in time. For SiO2-passivated rear surfaces of bifacial cells, measurements of the dependence of the surface recombination velocity on the excess carrier concentration are presented.

  2. Interaction of Epithelial Cells with Surfaces and Surfaces Decorated by Molecules

    CERN Document Server

    Martini, Daniele; Beil, Michael; Paust, T; Huang, C; Moosmann, M; Jin, J; Heiler, T; Gröger, R; Schimmel, Thomas; Walheim, Stefan

    2013-01-01

    A detailed understanding of the interface between living cells and substrate materials is of rising importance in many fields of medicine, biology and biotechnology. Cells at interfaces often form epithelia. The physical barrier that they form is one of their main functions. It is governed by the properties of the networks forming the cytoskeleton systems and by cell-to-cell contacts. Different substrates with varying surface properties modify the migration velocity of the cells. On the one hand one can change the materials composition. Organic and inorganic materials induce differing migration velocities in the same cell system. Within the same class of materials, a change of the surface stiffness or of the surface energy modifies the migration velocity, too. For our cell adhesion studies a variety of different, homogeneous substrates were used (polymers, bio-polymers, metals, oxides). In addition, an effective lithographic method, Polymer Blend Lithography (PBL), is reported, to produce patterned Self-Assem...

  3. Surface Plasmon Resonance for Cell-Based Clinical Diagnosis

    Directory of Open Access Journals (Sweden)

    Yuhki Yanase

    2014-03-01

    Full Text Available Non-invasive real-time observations and the evaluation of living cell conditions and functions are increasingly demanded in life sciences. Surface plasmon resonance (SPR sensors detect the refractive index (RI changes on the surface of sensor chips in label-free and on a real-time basis. Using SPR sensors, we and other groups have developed techniques to evaluate living cells’ reactions in response to stimuli without any labeling in a real-time manner. The SPR imaging (SPRI system for living cells may visualize single cell reactions and has the potential to expand application of SPR cell sensing for clinical diagnosis, such as multi-array cell diagnostic systems and detection of malignant cells among normal cells in combination with rapid cell isolation techniques.

  4. Functions of proteoglycans at the cell surface

    DEFF Research Database (Denmark)

    Höök, M; Woods, A; Johansson, S; Kjellén, L; Couchman, J R

    1986-01-01

    -associated proteoglycans, including: regulation of cell-substrate adhesion; regulation of cell proliferation; participation in the binding and uptake of extracellular components; and participation in the regulation of extracellular matrix formation. Evidence is discussed suggesting that the cell-associated heparan...... sulphate helps to connect the intracellular cytoskeleton to the extracellular matrix in focal adhesions. This evidence includes: the co-localization of actin and heparan sulphate proteoglycan during the process of cell spreading, and in isolated focal adhesions; biochemical analyses of a hydrophobic...... heparan sulphate proteoglycan from isolated focal adhesions; and the formation of focal adhesions on substrates made from isolated fibronectin fragments requires the presence of a heparan sulphate-binding site....

  5. Surface Passivation Studies on n+pp+ Bifacial Solar Cell

    OpenAIRE

    Suhaila Sepeai; M. Y. Sulaiman; Kamaruzzaman Sopian; Saleem H. Zaidi

    2012-01-01

    Bifacial solar cell is a specially designed solar cell for the production of electricity from both sides of the solar cell. It is an active field of research to make photovoltaics (PV) more competitive by increasing its efficiency and lowering its costs. We developed an n+pp+ structure for the bifacial solar cell. The fabrication used phosphorus-oxy-trichloride (POCl3) diffusion to form the emitter and Al diffusion using conventional screen printing to produce the back surface field (BSF). Th...

  6. A Simple Hydrophilic Treatment of SU-8 Surfaces for Cell Culturing and Cell Patterning

    DEFF Research Database (Denmark)

    Wang, Zhenyu; Stangegaard, Michael; Dufva, Hans Martin;

    2005-01-01

    SU-8, an epoxy-based photoresist, widely used in constitution different mTAS systems, is incompatible with mammalian cell adhesion and culture in its native form. Here, we demonstrate a simple, cheap and robust two-step method to render a SU-8 surface hydrophilic and compatible with cell culture....... The contact angle of SU-8 surface was significantly reduced from 90° to 25° after the surface modification. The treated SU-8 surfaces provided a cell culture environment that was comparable with cell culture flask surface in terms of generation time and morphology....

  7. Ancestral vascular lumen formation via basal cell surfaces.

    Directory of Open Access Journals (Sweden)

    Tomás Kucera

    Full Text Available The cardiovascular system of bilaterians developed from a common ancestor. However, no endothelial cells exist in invertebrates demonstrating that primitive cardiovascular tubes do not require this vertebrate-specific cell type in order to form. This raises the question of how cardiovascular tubes form in invertebrates? Here we discovered that in the invertebrate cephalochordate amphioxus, the basement membranes of endoderm and mesoderm line the lumen of the major vessels, namely aorta and heart. During amphioxus development a laminin-containing extracellular matrix (ECM was found to fill the space between the basal cell surfaces of endoderm and mesoderm along their anterior-posterior (A-P axes. Blood cells appear in this ECM-filled tubular space, coincident with the development of a vascular lumen. To get insight into the underlying cellular mechanism, we induced vessels in vitro with a cell polarity similar to the vessels of amphioxus. We show that basal cell surfaces can form a vascular lumen filled with ECM, and that phagocytotic blood cells can clear this luminal ECM to generate a patent vascular lumen. Therefore, our experiments suggest a mechanism of blood vessel formation via basal cell surfaces in amphioxus and possibly in other invertebrates that do not have any endothelial cells. In addition, a comparison between amphioxus and mouse shows that endothelial cells physically separate the basement membranes from the vascular lumen, suggesting that endothelial cells create cardiovascular tubes with a cell polarity of epithelial tubes in vertebrates and mammals.

  8. Interaction between Hanseniaspora uvarum and Saccharomyces cerevisiae during alcoholic fermentation.

    Science.gov (United States)

    Wang, Chunxiao; Mas, Albert; Esteve-Zarzoso, Braulio

    2015-08-01

    During wine fermentation, Saccharomyces clearly dominate over non-Saccharomyces wine yeasts, and several factors could be related to this dominance. However, the main factor causing the reduction of cultivable non-Saccharomyces populations has not yet been fully established. In the present study, various single and mixed fermentations were performed to evaluate some of the factors likely responsible for the interaction between Saccharomyces cerevisiae and Hanseniaspora uvarum. Alcoholic fermentation was performed in compartmented experimental set ups with ratios of 1:1 and 1:9 and the cultivable population of both species was followed. The cultivable H. uvarum population decreased sharply at late stages when S. cerevisiae was present in the other compartment, similarly to alcoholic fermentations in non-compartmented vessels. Thus, cell-to-cell contact did not seem to be the main cause for the lack of cultivability of H. uvarum. Other compounds related to fermentation performance (such as sugar and ethanol) and/or certain metabolites secreted by S. cerevisiae could be related to the sharp decrease in H. uvarum cultivability. When these factors were analyzed, it was confirmed that metabolites from S. cerevisiae induced lack of cultivability in H. uvarum, however ethanol and other possible compounds did not seem to induce this effect but played some role during the process. This study contributes to a new understanding of the lack of cultivability of H. uvarum populations during the late stages of wine fermentation. PMID:25956738

  9. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    International Nuclear Information System (INIS)

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity

  10. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alan M. [School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH (United Kingdom); Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L. [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom); Grover, Liam M., E-mail: l.m.grover@bham.ac.uk [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)

    2015-03-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity.

  11. Surface passivation of high efficiency silicon solar cells

    International Nuclear Information System (INIS)

    Theoretically and experimentally determined design guides for significantly reducing recombination at the emitter and rear surfaces of full-area Al-BSF and oxide passivated bifacial cells are given. The impact of emitter thickness and surface dopant concentration on emitter saturation current and solar cell efficiency is outlined. A modified emitter structure (locally deep diffused below the metal contacts) is predicted to have superior performance. Measured Voc-values reveal the potential of deep emitter cells to achieve efficiencies above 20% in spite of high metallization factors. Experimentally the authors find a strong dependence of passivation quality on oxide thickness and base doping concentration. The BSF quality of a diffused aluminum layer decreases strongly with increasing drive-in- time. For SiO2-passivated rear surfaces of bifacial cells measurements of the dependence of the surface recombination velocity on the excess carrier concentration are presented

  12. Cell orientation on a stripe-micropatterned surface

    Institute of Scientific and Technical Information of China (English)

    SUN JianGuo; TANG Jian; DING JianDong

    2009-01-01

    Stripe-micropatterned surfaces have recently been a unique tool to study cell orientation. In this paper,we prepared,by the photolithography transfer technique,stable gold (Au) micropatterns on PEG hydrogel surfaces with defined cell-resistant (PEG hydrogel) and cell-adhesive (gold microstripes) proparties. 3T3 fibroblasts were cultured on Au-microstripe surfaces to observe cell adhesion and orientation. Five statistical parameters were defined and used to describe cell orientation on micropatterns.With the increase of inter-stripe distance,the orientational order parameter,the ratio of long and short axes of a cell,and the occupation fraction of cells on stripes increased gradually,whereas the spreading area of a single cell decreased. The abrupt changes of these four parameters did not happen at the same inter-distance. The adhesion ratio of a cell on Au stripes over cell spreading area did not change monotonically as a function of inter-stripe distance. The combination of the 5 statistical parameters represented well the cell orientation behaviors semi-quantitatively.

  13. Counting NMDA Receptors at the Cell Surface

    Czech Academy of Sciences Publication Activity Database

    Horák, Martin; Suh, Y. H.

    Totowa: Humana Press Inc., 2016, s. 31-44. (Neuromethods. 106). ISBN 978-1-4939-2811-8 R&D Projects: GA ČR(CZ) GA14-02219S Institutional support: RVO:67985823 Keywords : NMDA receptor * ionotropic glutamate receptor * mammalian cell lines * intracellular trafficking * quantitative assay * biotinylation assay * biochemistry Subject RIV: FH - Neurology

  14. Human Papillomavirus Infection Requires Cell Surface Heparan Sulfate

    OpenAIRE

    Giroglou, Tzenan; Florin, Luise; Schäfer, Frank; Streeck, Rolf E.; Sapp, Martin

    2001-01-01

    Using pseudoinfection of cell lines, we demonstrate that cell surface heparan sulfate is required for infection by human papillomavirus type 16 (HPV-16) and HPV-33 pseudovirions. Pseudoinfection was inhibited by heparin but not dermatan or chondroitin sulfate, reduced by reducing the level of surface sulfation, and abolished by heparinase treatment. Carboxy-terminally deleted HPV-33 virus-like particles still bound efficiently to heparin. The kinetics of postattachment neutralization by antis...

  15. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer.

    Science.gov (United States)

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  16. Recent Insights into Cell Surface Heparan Sulphate Proteoglycans and Cancer

    Science.gov (United States)

    Couchman, John R; Multhaupt, Hinke; Sanderson, Ralph D.

    2016-01-01

    A small group of cell surface receptors are proteoglycans, possessing a core protein with one or more covalently attached glycosaminoglycan chains. They are virtually ubiquitous and their chains are major sites at which protein ligands of many types interact. These proteoglycans can signal and regulate important cell processes, such as adhesion, migration, proliferation, and differentiation. Since many protein ligands, such as growth factors, morphogens, and cytokines, are also implicated in tumour progression, it is increasingly apparent that cell surface proteoglycans impact tumour cell behaviour. Here, we review some recent advances, emphasising that many tumour-related functions of proteoglycans are revealed only after their modification in processes subsequent to synthesis and export to the cell surface. These include enzymes that modify heparan sulphate structure, recycling of whole or fragmented proteoglycans into exosomes that can be paracrine effectors or biomarkers, and lateral interactions between some proteoglycans and calcium channels that impact the actin cytoskeleton. PMID:27408707

  17. Surface texturing of multicrystalline silicon solar cells

    OpenAIRE

    L.A. Dobrzański; A. Drygała

    2008-01-01

    Purpose: The aim of the paper is to elaborate a laser method of texturization multicrystalline silicon. The main reason for taking up the research is that most conventional methods used for texturization of monocrystalline silicon are ineffective when applied for texturing multicrystalline silicon. This is related to random distribution of grains of different crystalographic orientations on the surface of multicrystalline silicon.Design/methodology/approach: The topography of laser ...

  18. Surface immobilized protein multilayers for cell seeding

    Czech Academy of Sciences Publication Activity Database

    Brynda, Eduard; Pacherník, J.; Houska, Milan; Pientka, Zbyněk; Dvořák, P.

    2005-01-01

    Roč. 21, č. 17 (2005), s. 7877. ISSN 0743-7463 R&D Projects: GA ČR(CZ) GA203/02/1326; GA ČR GA102/03/0633; GA MŠk(CZ) LN00A065 Keywords : surface modification * layer-by-layer deposition * protein multilayers Subject RIV: CE - Biochemistry Impact factor: 3.705, year: 2005

  19. Multi-scale cell/surface interaction on modified titanium aluminum vanadium surfaces

    Science.gov (United States)

    Chen, Jianbo

    This dissertation presents a series of experimental studies of the effects of multi-scale cell/surface interactions on modified Ti-6Al-4V surfaces. These include laser-grooved surfaces; porous structures and RGD-coated laser-grooved surfaces. A nano-second DPSS UV lasers with a Gaussian pulse energy profile was used to introduce the desired micro-groove geometries onto Ti-6Al-4V surfaces. This was done without inducing micro-cracks or significant changes in surface chemistry within the heat affected zones. The desired 8-12 mum groove depths and widths were achieved by the control of pulse frequency, scan speed, and the lens focal length that controls spot size. The interactions between human osteosarcoma (HOS) cells and laser-grooved Ti-6Al-4V surfaces were investigated after 48 hours of cell culture. The cell behavior, including cell spreading, alignment and adhesion, was elucidated using scanning electronic microscopy (SEM), immuno-fluorescence staining and enzymatic detachment. Contact guidance was shown to increase as grooved spacing decreased. For the range of micro-groove geometries studied, micro-grooves with groove spacings of 20 mum provided the best combination of cell orientation and adhesion. Short-term adhesion experiments (15 mins to 1 day) also revealed that there is a positive correlation between cell orientation and cell adhesion. Contact guidance on the micro-grooved surfaces is shown to be enhanced by nano- and micro-scale asperities that provide sites for the attachment of lamellopodia during cell locomotion and spreading. Contact guidance is also promoted by the geometrical confinement provided by laser grooves. An experimental study of initial cell spreading and ingrowth into Ti-6Al-4V porous structures was also carried out on porous structures with different pore sizes and geometries. A combination of SEM, the tetrazolium salt (MTT) colorimetric assay and enzymatic detachment were used to study cell spreading and adhesion. The extent of cell

  20. 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.

  1. Immunogold labels: cell-surface markers in atomic force microscopy

    NARCIS (Netherlands)

    Putman, Constant A.J.; Grooth, de Bart G.; Hansma, Paul K.; Hulst, van Niek F.; Greve, Jan

    1993-01-01

    The feasibility of using immunogold labels as cell-surface markers in atomic force microscopy is shown in this paper. The atomic force microscope (AFM) was used to image the surface of immunogold-labeled human lymphocytes. The lymphocytes were isolated from whole blood and labeled by an indirect imm

  2. Expanding the diversity of unnatural cell surface sialic acids

    Energy Technology Data Exchange (ETDEWEB)

    Luchansky, Sarah J.; Goon, Scarlett; Bertozzi, Carolyn R.

    2003-10-30

    Novel chemical reactivity can be introduced onto cell surfaces through metabolic oligosaccharide engineering. This technique exploits the substrate promiscuity of cellular biosynthetic enzymes to deliver unnatural monosaccharides bearing bioorthogonal functional groups into cellular glycans. For example, derivatives of N-acetylmannosamine (ManNAc) are converted by the cellular biosynthetic machinery into the corresponding sialic acids and subsequently delivered to the cell surface in the form of sialoglycoconjugates. Analogs of N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) are also metabolized and incorporated into cell surface glycans, likely through the sialic acid and GalNAc salvage pathways, respectively. Furthermore, GlcNAc analogs can be incorporated into nucleocytoplasmic proteins in place of {beta}-O-GlcNAc residues. These pathways have been exploited to integrate unique electrophiles such as ketones and azides into the target glycoconjugate class. These functional groups can be further elaborated in a chemoselective fashion by condensation with hydrazides and by Staudinger ligation, respectively, thereby introducing detectable probes onto the cell. In conclusion, sialic acid derivatives are efficient vehicles for delivery of bulky functional groups to cell surfaces and masking of their hydroxyl groups improves their cellular uptake and utilization. Furthermore, the successful introduction of photoactivatable aryl azides into cell surface glycans opens up new avenues for studying sialic acid-binding proteins and elucidating the role of sialic acid in essential processes such as signaling and cell adhesion.

  3. Biosorption of 241Am by Saccharomyces cerevisiae. Preliminary investigation on mechanism

    International Nuclear Information System (INIS)

    As an important radioisotope in nuclear industry and other fields, 241Am is one of the most serious contamination concerns due to its high radiation toxicity and long half-life. The encouraging biosorption of 241Am from aqueous solutions by free or immobilized Saccharomyces cerevisiae (S. cerevisiae) has been observed in our previous experiments. In this study, the preliminary evaluation on mechanism was further explored via chemical or biological modification of S. cerevisiae, and using europium as a substitute for americium. The results indicated that the culture times of more than 16 hours for S. cerevisiae was suitable and the efficient adsorption of 241Am by the S. cerevisiae was able to achieve. The pH value in solutions decreased gradually with the uptake of 241Am in the S. cerevisiae, implying that H+ released from S. cerevisiae via ion-exchange. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus. However, the adsorption ratio for 241Am by the deproteinized or deacylated S. cerevisiae dropped obviously, implying that protein or carboxyl functional groups of S. cerevisiaece play an important role in the biosorption of 241Am. Most of the investigated acidic ions have no significant influence on the 241Am adsorption, while the saturated EDTA can strong inhibit the biosorption of 241Am on S. cerevisiae. When the concentrations of coexistent Eu3+, Nd3+ were 100 times more than that of 241Am, the adsorption ratios would decrease to 65% from more than 95%. It could be noted by transmission electron microscope (TEM) analysis that the adsorbed Eu is almost scattered in the whole fungus, while Rutherford backscattering spectrometry (RBS) analysis indicated that Ca in S. cerevisiae have been replaced by Eu via ion-exchange. All the results implied that the adsorption mechanism of 241Am on S. cerevisiae is very complicated and at least involved in ion exchange, complexation

  4. Morphological change and enhanced pigment production of monascus when cocultured with saccharomyces cerevisiae or aspergillus oryzae

    Science.gov (United States)

    Shin; Kim; Kim; Ju

    1998-09-01

    When a Monascus isolate, a producer of Monascus pigments, was cocultured with either Saccharomyces cerevisiae or Aspergillus oryzae in a solid sucrose medium, there were significant morphological changes in Monascus culture. Cocultures exhibited cell mass increases of 2 times and pigment yield increases of 30 to 40 times compared to monocultures of Monascus. However, enhanced cell growth, an increase in pigment production, and morphological change did not occur in coculture with Bacillus cereus. Saccharomyces cerevisiae was more effective at enhancing pigment production than Asp. oryzae. Enhanced cell growth and increased pigment production occurred only in conjunction with morphological changes. Culture filtrates of S. cerevisiae were also effective in inducing morphology change in Monascus, similar to culture broths of S. cerevisiae. The hydrolytic enzymes produced by S. cerevisiae, such as amylase, and chitinase, are thought to be the effectors. The commercial enzymes alpha-amylase and protease from Asp. oryzae both caused a morphological change in Monascus and were effective in enhancing pigment production. However, lysozyme, alpha-amylase and protease from Bacillus species, protease from Staphylococcus, and chitinase from Streptomyces were not effective. The hydrolytic enzymes which cause a morphological change of Monascus culture and enhancement of pigment production are thought to be capable of degrading Monascus cell walls. An approximate 10-fold increase in pigment production was observed in liquid cocultures with S. cerevisiae. Copyright 1998 John Wiley & Sons, Inc. PMID:10099374

  5. Amplified effect of surface charge on cell adhesion by nanostructures

    Science.gov (United States)

    Xu, Li-Ping; Meng, Jingxin; Zhang, Shuaitao; Ma, Xinlei; Wang, Shutao

    2016-06-01

    Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration.Nano-biointerfaces with varied surface charge can be readily fabricated by integrating a template-based process with maleimide-thiol coupling chemistry. Significantly, nanostructures are employed for amplifying the effect of surface charge on cell adhesion, as revealed by the cell-adhesion performance, cell morphology and corresponding cytoskeletal organization. This study may provide a promising strategy for developing new biomedical materials with tailored cell adhesion for tissue implantation and regeneration. Electronic supplementary information (ESI) available: Experimental details, SEM, KFM AFM, chemical modification and characterization. See DOI: 10.1039/c6nr00649c

  6. Standing surface acoustic wave (SSAW) based multichannel cell sorting

    OpenAIRE

    Ding, Xiaoyun; Lin, Sz-Chin Steven; Lapsley, Michael Ian; Li, Sixing; Guo, Xiang; Chan, Chung Yu Keith; Chiang, I-Kao; Wang, Lin; McCoy, J. Philip; Huang, Tony Jun

    2012-01-01

    We introduce a novel microfluidic device for cell sorting in continuous flow using tunable standing surface acoustic waves. This method allows individual cells to be precisely directed into five different outlet channels in a single step. It is versatile, simple, label-free, non-invasive, and highly controllable.

  7. Study of surface cell Madelung constant and surface free energy of nanosized crystal grain

    Institute of Scientific and Technical Information of China (English)

    Zhang Wei-Jia; Wang Tian-Min; Rong Ai-Lun; Cui Min

    2006-01-01

    Surface cell Madelung constant is firstly defined for calculating the surface free energy of nanosized crystal grains,which explains the physical performance of small crystals and may be greatly beneficial to the analysis of surface states and the study of the dynamics of crystal nucleation and growth.A new approximative expression of the surface energy and relevant thermodynamic data are used in this calculation.New formula and computing method for calculating the Madelung constant α of any complex crystals are proposed,and the surface free energies and surface electrostatic energies of nanosized crystal grains and the Madelung constant of some complex crystals are theoretically calculated in this paper.The surface free energy of nanosized-crystal-grain TiO2 and the surface electrostatic energy (absolute value) of nanosized-crystal-grain α-A12O3 are found to be the biggest among all the crystal grains including those of other species.

  8. Study of Surface Cell Madelung Constant and Surface Free Energy of Nanosized Crystal Grain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-Jia; WANG Tian-Min; CUI Min

    2005-01-01

    Surface cell Madelung constant is firstly defined in calculating surface free energy of nanosized crystal grains, which explains the physical performance of small crystals and may be great benefit to make surface analysis and study dynamics of crystal nucleus growth. A new ap- proximative expression of surface energy and relevant thermodynamic data was used in this cal- culation. A new formula and computing method for calculating the Madelung constant α of any complex crystals is proposed, and surface free energies and surface electrostatic energies of nano- sized crystal grains as well as Madelung constant of some complex crystals are theoretically cal- culated in this paper. The surface free energy of nanosized crystal grain TiO2 and surface elec- trostatic energy(absolute value) of nanosized crystal grain α-Al2O3 are found to be the biggest among other crystal grains.

  9. Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

    International Nuclear Information System (INIS)

    The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ≤ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

  10. Zinc uptake by brain cells: `surface' versus `bulk'

    Science.gov (United States)

    DeStasio, Gelsomina; Pochon, S.; Lorusso, G. F.; Tonner, B. P.; Mercanti, Delio; Ciotti, M. Teresa; Oddo, Nino; Galli, Paolo; Perfetti, P.; Margaritondo, G.

    1996-08-01

    The uptake of zinc by cerebellar rat cultures upon exposure to 0022-3727/29/8/023/img12 solutions was comparatively investigated using two well known condensed matter physics techniques: synchrotron photoelectron spectromicroscopy and inductively coupled plasma atomic emission spectroscopy. The objective was to apply a strategy - well known in surface physics - to distinguish between `surface' and `bulk' phenomena. The results clearly demonstrate that exposure significantly enhances the bulk (cell cytoplasm) Zn concentration with respect to the physiological level, whereas the effect on the surface (cell membrane) is negligible.

  11. Micropatterned Surfaces to Study Hyaluronic Acid Interactions with Cancer Cells

    OpenAIRE

    Dickinson, Laura E.; Gerecht, Sharon

    2010-01-01

    Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix (ECM) components within the tumor microenvironment. Hyaluronic acid (HA) is one stromal ECM component that is known to facilitate tumor progression by enhancing invasion, growth, and angiogenesis1. Interaction of HA with its cell surface receptor CD44 induces signaling events that promote tumor cell growth, survival, and migration, thereby in...

  12. 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. PMID:26658003

  13. Influence of engineered surface on cell directionality and motility

    International Nuclear Information System (INIS)

    Control of cell migration is important in numerous key biological processes, and is implicated in pathological conditions such as cancer metastasis and inflammatory diseases. Many previous studies indicated that cell migration could be guided by micropatterns fabricated on cell culture surfaces. In this study, we designed a polydimethylsiloxane cell culture substrate with gratings punctuated by corners and ends, and studied its effects on the behavior of MC3T3-E1 osteoblast cells. MC3T3-E1 cells elongated and aligned with the gratings, and the migration paths of the cells appeared to be guided by the grating pattern. Interestingly, more than 88% of the cells cultured on these patterns were observed to reverse their migration directions at least once during the 16 h examination period. Most of the reversal events occurred at the corners and the ends of the pattern, suggesting these localized topographical features induce an abrupt loss in directional persistence. Moreover, the cell speed was observed to increase temporarily right after each directional reversal. Focal adhesion complexes were more well-established in cells on the angular gratings than on flat surfaces, but the formation of filipodia appeared to be imbalanced at the corners and the ends, possibly leading to the loss of directional persistence. This study describes the first engineered cell culture surface that consistently induces changes in the directional persistence of adherent cells. This will provide an experimental model for the study of this phenomenon and a valuable platform to control the cell motility and directionality, which can be used for cell screening and selection. (paper)

  14. Surface strategies for control of neuronal cell adhesion: A review

    Science.gov (United States)

    Roach, P.; Parker, T.; Gadegaard, N.; Alexander, M. R.

    2010-06-01

    Material engineering methods have been used for many years to develop biomedical devices for use within the body to augment, repair or replace damaged tissues ranging from contact lenses to heart valves. Here we review the findings gathered from the wide and varied surface analytical approaches applied to study the interaction between biology and man-made materials. The key material characteristics identified to be important for biological recognition are surface chemistry, topography and compliance. Model surfaces with controlled chemistry and topography have provided insight into biological response to various types of topographical features over a wide range of length scales from nano to micrometres, along with 3D matrices that have been used as scaffolds to support cells for tissue formation. The cellular response to surfaces with localised areas of patterned chemistry and to those presenting gradually changing chemistry are discussed. Where previous reviews have been structured around specific classes of surface modification, e.g. self-assembly, or have broadly examined the response of various cells to numerous surfaces, we aim in this article to focus in particular on the tissues involved in the nervous system whilst providing a broad overview of key issues from the field of cell and protein surface interactions with surfaces. The goal of repair and treatment of diseases related to the central and peripheral nervous systems rely on understanding the local interfacial environment and controlling responses at the cellular level. The role of the protein layer deposited from serum containing media onto man-made surfaces is discussed. We highlight the particular problems associated with the repair of the nervous system, and review how neuronal attachment and axon guidance can be accomplished using various surface cues when cultured with single and multiple cell types. We include a brief glossary of techniques discussed in the body of this article aimed at the

  15. The Response to Heat Shock and Oxidative Stress in Saccharomyces cerevisiae

    OpenAIRE

    Morano, Kevin A.; Grant, Chris M.; Moye-Rowley, W. Scott

    2012-01-01

    A common need for microbial cells is the ability to respond to potentially toxic environmental insults. Here we review the progress in understanding the response of the yeast Saccharomyces cerevisiae to two important environmental stresses: heat shock and oxidative stress. Both of these stresses are fundamental challenges that microbes of all types will experience. The study of these environmental stress responses in S. cerevisiae has illuminated many of the features now viewed as central to ...

  16. Heat shock decrease Saccharomyces cerevisiae UE-ME3 survival exposed to nanoparticles of titanium dioxide.

    OpenAIRE

    Capela-Pires, JM; I. Alves-Pereira; Ferreira, Rui

    2011-01-01

    The main objective of this study was to evaluate the effect of temperature in Saccharomyces cerevisiae exposed to nanoparticles of titanium dioxide (NP-TiO2), because there are scarces studies to evaluate the toxic effects of NP-TiO2 in eukaryote cells. S. cerevisiae UE-ME3, wild-type yeast, belonging to the Enology laboratory collection of University of Evora

  17. Identification and Characterization of a Novel Biotin Biosynthesis Gene in Saccharomyces cerevisiae

    OpenAIRE

    Wu, Hong; Ito, Kiyoshi; Shimoi, Hitoshi

    2005-01-01

    Yeast Saccharomyces cerevisiae cells generally cannot synthesize biotin, a vitamin required for many carboxylation reactions. Although sake yeasts, which are used for Japanese sake brewing, are classified as S. cerevisiae, they do not require biotin for their growth. In this study, we identified a novel open reading frame (ORF) in the genome of one strain of sake yeast that we speculated to be involved in biotin synthesis. Homologs of this gene are widely distributed in the genomes of sake ye...

  18. Directed Evolution of Xylose Isomerase for Improved Xylose Catabolism and Fermentation in the Yeast Saccharomyces cerevisiae

    OpenAIRE

    Lee, Sun-Mi; Jellison, Taylor; Alper, Hal S.

    2012-01-01

    The heterologous expression of a highly functional xylose isomerase pathway in Saccharomyces cerevisiae would have significant advantages for ethanol yield, since the pathway bypasses cofactor requirements found in the traditionally used oxidoreductase pathways. However, nearly all reported xylose isomerase-based pathways in S. cerevisiae suffer from poor ethanol productivity, low xylose consumption rates, and poor cell growth compared with an oxidoreductase pathway and, additionally, often r...

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

    International Nuclear Information System (INIS)

    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)

  20. Estimating intercellular surface tension by laser-induced cell fusion

    International Nuclear Information System (INIS)

    Intercellular surface tension is a key variable in understanding cellular mechanics. However, conventional methods are not well suited for measuring the absolute magnitude of intercellular surface tension because these methods require determination of the effective viscosity of the whole cell, a quantity that is difficult to measure. In this study, we present a novel method for estimating the intercellular surface tension at single-cell resolution. This method exploits the cytoplasmic flow that accompanies laser-induced cell fusion when the pressure difference between cells is large. Because the cytoplasmic viscosity can be measured using well-established technology, this method can be used to estimate the absolute magnitudes of tension. We applied this method to two-cell-stage embryos of the nematode Caenorhabditis elegans and estimated the intercellular surface tension to be in the 30–90 µN m−1 range. Our estimate was in close agreement with cell–medium surface tensions measured at single-cell resolution. (communication)

  1. Fibronectin adsorption, cell adhesion, and proliferation on nanostructured tantalum surfaces.

    Science.gov (United States)

    Dolatshahi-Pirouz, A; Jensen, T; Kraft, David Christian; Foss, Morten; Kingshott, Peter; Hansen, John Lundsgaard; Larsen, Arne Nylandsted; Chevallier, Jacques; Besenbacher, Flemming

    2010-05-25

    The interaction between dental pulp derived mesenchymal stem cells (DP-MSCs) and three different tantalum nanotopographies with and without a fibronectin coating is examined: sputter-coated tantalum surfaces with low surface roughness tantalum surfaces were examined, as well as cellular attachment, proliferation, and vinculin focal adhesion spot assembly on the respective surfaces. The results showed the highest fibronectin mass uptake on the hut structures, with a slightly higher availability of cell-binding domains and the most pronounced formation of vinculin focal adhesion spots as compared to the other surfaces. The proliferation of DP-MSCs was found to be significantly higher on dome and hut surfaces coated with fibronectin compared to the uncoated flat tantalum surfaces. Consequently, the results presented in this study indicate that fibronectin-coated nanotopographies with a vertical dimension of less than 5 nm influence cell adhesion. This rather interesting behavior is argued to originate from the more available fibronectin cell-binding domains observed on the hut structures. PMID:20443575

  2. 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.

  3. Surface modified stainless steels for PEM fuel cell bipolar plates

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Wang, Heli [Littleton, CO; Turner, John A [Littleton, CO

    2007-07-24

    A nitridation treated stainless steel article (such as a bipolar plate for a proton exchange membrane fuel cell) having lower interfacial contact electrical resistance and better corrosion resistance than an untreated stainless steel article is disclosed. The treated stainless steel article has a surface layer including nitrogen-modified chromium-base oxide and precipitates of chromium nitride formed during nitridation wherein oxygen is present in the surface layer at a greater concentration than nitrogen. The surface layer may further include precipitates of titanium nitride and/or aluminum oxide. The surface layer in the treated article is chemically heterogeneous surface rather than a uniform or semi-uniform surface layer exclusively rich in chromium, titanium or aluminum. The precipitates of titanium nitride and/or aluminum oxide are formed by the nitriding treatment wherein titanium and/or aluminum in the stainless steel are segregated to the surface layer in forms that exhibit a low contact resistance and good corrosion resistance.

  4. Cell adhesion and growth on ion-implanted polymer surface

    International Nuclear Information System (INIS)

    The adhesion and growth of endothelial cells on ion-implanted polystyrene and segmented polyurethane surface were investigated. Ions of Na+, N2+, O2+, Ar+ and Kr+ were implanted to the polymer surface with ion fluences between 1 x 1015 and 3 x 1017 ions/cm2 at energy of 150 KeV at room temperature. Ion-implanted polymers were characterized by FT-IR-ATR an Raman spectroscopies. The adhesion and proliferation of bovine aorta endothelial cells on ion-implanted polymer surface were observed by an optical microscope. The rate of growth of BAECs on ion-implanted PSt was faster than that on non-implanted PSt. Complete cell adhesion and growth were observed on ion-implanted SPU, whereas the adhesion and growth of BAECs on the non-implanted SPU was not observed. It was attempted to control the cell culture on the ion-implanted domain fabricated using a mask. (author)

  5. Surface modification of closed plastic bags for adherent cell cultivation

    Science.gov (United States)

    Lachmann, K.; Dohse, A.; Thomas, M.; Pohl, S.; Meyring, W.; Dittmar, K. E. J.; Lindenmeier, W.; Klages, C.-P.

    2011-07-01

    In modern medicine human mesenchymal stem cells are becoming increasingly important. However, a successful cultivation of this type of cells is only possible under very specific conditions. Of great importance, for instance, are the absence of contaminants such as foreign microbiological organisms, i.e., sterility, and the chemical functionalization of the ground on which the cells are grown. As cultivation of these cells makes high demands, a new procedure for cell cultivation has been developed in which closed plastic bags are used. For adherent cell growth chemical functional groups have to be introduced on the inner surface of the plastic bag. This can be achieved by a new, atmospheric-pressure plasma-based method presented in this paper. The method which was developed jointly by the Fraunhofer IST and the Helmholtz HZI can be implemented in automated equipment as is also shown in this contribution. Plasma process gases used include helium or helium-based gas mixtures (He + N2 + H2) and vapors of suitable film-forming agents or precursors such as APTMS, DACH, and TMOS in helium. The effect of plasma treatment is investigated by FTIR-ATR spectroscopy as well as surface tension determination based on contact angle measurements and XPS. Plasma treatment in nominally pure helium increases the surface tension of the polymer foil due to the presence of oxygen traces in the gas and oxygen diffusing through the gas-permeable foil, respectively, reacting with surface radical centers formed during contact with the discharge. Primary amino groups are obtained on the inner surface by treatment in mixtures with nitrogen and hydrogen albeit their amount is comparably small due to diffusion of oxygen through the gas-permeable bag, interfering with the plasma-amination process. Surface modifications introducing amino groups on the inner surface turned out to be most efficient in the promotion of cell growth.

  6. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  7. Biosensing based on surface plasmon resonance and living cells.

    Science.gov (United States)

    Chabot, Vincent; Cuerrier, Charles M; Escher, Emanuel; Aimez, Vincent; Grandbois, Michel; Charette, Paul G

    2009-02-15

    We propose the combination of surface plasmon resonance (SPR) with living cells as a biosensing method. Our detection scheme is based on the premise that cellular activity induced by external agents is often associated with changes in cellular morphology, which in turn should lead to a variation of the effective refractive index at the interface between the cell membrane and the metal layer. We monitored surface plasmon resonance signals originating from a gold surface coated with cells on a custom apparatus after injection of various agents known to influence cellular activity and morphology. Specifically, we evaluated three types of stimulation: response to an endotoxin (lipopolysaccharides), a chemical toxin (sodium azide) and a physiological agonist (thrombin). A comparison with phase contrast microscopy reveals that SPR signal variations are associated with the induction of cell death for lipopolysaccharides treatment and a contraction of the cell body for sodium azide. Thrombin-induced cellular response shows a rapid decrease of the measured laser reflectance over 5min followed by a return to the original value. For this treatment, phase contrast micrographs relate the first phase of the SPR variation to cell contraction and increase of the intercellular gaps, whereas the recovery phase can be associated with a spreading of the cell on the sensing surface. Hence, the SPR signal is very consistent with the cellular response normally observed for these treatments. This confirms the validity of the biosensing method, which could be applied to a large variety of cellular responses involving shape remodeling induced by external agents. PMID:18845432

  8. Engineered microtopographies and surface chemistries direct cell attachment and function

    Science.gov (United States)

    Magin, Chelsea Marie

    Harrison, in 1914, first recognized that cells respond to physicochemical cues such as substratum topography when he observed that fibroblasts elongated while cultured on spider silk. Recently, techniques developed in the micro-electronics industry have been used to create molds for producing microscaled topographies with various shapes and spatial arrangements. Although these patterning techniques are well-established, very little is known about the mechanisms underlying cell sensing and response to microtopographies. In this work cellular micro-environments with varying surface topographies and chemistries were evaluated with marine organisms and mammalian cells to investigate cellular sensing and response. Biofouling---the accumulation of micro-organisms, plants, and animals on submerged surfaces---is an environmental and economic concern. Engineered topographies, replicated in polydimethylsiloxane elastomer (PDMSe) and functionalized poly(ethylene glycol)-dimethacrylate (PEGDMA) hydrogels, were evaluated for inhibition of marine fouling organism attachment. Microtopographies replicated in PDMSe inhibited attachment of the marine bacterium, Cobetia marina up to 99% versus smooth. The average normalized attachment densities of cells of C. marina and zoospores of the green algae Ulva on PDMSe topographies scaled inversely with the Engineered Roughness Index (ERIII), a representation of surface energy. Attachment densities of Ulva from four assays and C. marina from two growth phases to PDMSe surfaces scaled inversely with one equation: ERI II multiplied by the Reynolds number of the organism (Re) (R 2 = 0.77). The same microtopographies created in PDMSe reduced the initial attachment density and attachment strength of cells of the diatoms Navicula incerta and Seminavis robusta compared to smooth PDMSe. The average normalized attachment density of Navicula after exposure to shear stress (48 Pa) was correlated with the contact area between the diatom and a

  9. Pengaruh Media Tumbuh terhadap Kadar Protein Saccharomyces cerevisiae dalam Pembuatan Protein Sel Tunggal

    Directory of Open Access Journals (Sweden)

    RATNA SETYANINGSIH

    2004-11-01

    Full Text Available The aim of this research was to examine the influence of difference growth media, i. e. tofu liquid waste, tofu solid waste, and coconut water in various composition and Yeast Extract Peptone Dextrose (YEPD, to protein contents of Saccharomyces cerevisiae in Single Cell Protein (SCP production. The framework of this research was that tofu liquid waste, tofu solid waste, and coconut water were containing a lot of carbons, nitrogens, minerals, and vitamin that could be used as growth medium of S. cerevisiae to produce SCP, which was commonly used. The medium from tofu liquid waste and the coconut water were made by ratio 2:1, 1:1, 1:2 and added with tofu solid waste 1.5 g and 2.5 g. Then, the measurement of pH medium, the amount of cell, cell dried weight, and the protein content in S. cerevisiae was done. The measurement of protein content was done by Lowry method. The result of the research showed that growth media influenced protein content of S. cerevisiae. Protein content of S. cerevisiae cultured in tofu liquid waste- coconut water was lower then in YEPD medium. The protein content of S. cerevisiae cultured in tofu liquid waste and coconut water ratio 1:2, added with 2.5 g tofu solid waste was higher then in other medium composition.

  10. Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.

    Science.gov (United States)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Yamasaki, Shinya; Kozai, Naofumi; Shiotsu, Hiroyuki; Utsunomiya, Satoshi; Watanabe, Naoko; Kozaki, Tamotsu

    2015-06-01

    The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite > vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals. PMID:25841115

  11. Hepatic Bel-7402 Cell Proliferation on Different Phospholipid Surfaces

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Phospholipids are believed to be important biomaterials.However, limited information is available on their cytocompatibilities.The objective of this study is to evaluate the effects of different phospholipids on the proliferation of hepatic Bel-7402 cells by comparing the adhesion, viability and proliferation of Bel-7402 cells cultured on different phospholipid surfaces.The cell adhesion, determined by counting the number of adhered cells to the surface, indicated that the cell adhesion was enhanced on charged phospolipid membranes.The cell viability evaluated by MTT[3 (4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium-bromide] showed that cells cultured on charged phospholipids have greater viability than those cultured on the control, while cells cultured on neutral phospholipids showed lower viability.The cell cycle analysis using flow cytometry demonstrated that S phase entry increased on charged phospholipids, while S phase entry decreased on neutral phospholipids.The results suggested that charged phospholipids, especially positively charged phospholipids, show better cytocompatibilities than neutral phospholipids to hepatic Bel-7402 cell.

  12. Toxicity of chlorinated phenoxyacetic acid herbicides in the experimental eukaryotic model Saccharomyces cerevisiae: role of pH and of growth phase and size of the yeast cell population.

    Science.gov (United States)

    Cabral, M G; Viegas, C A; Teixeira, M C; Sá-Correia, I

    2003-04-01

    The inhibitory effect of the herbicides 2-methyl-4-chlorophenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D) in Saccharomyces cerevisiae growth is strongly dependent on medium pH (range 2.5-6.5). Consistent with the concept that the toxic form is the liposoluble undissociated form, at values close to their pK(a) (3.07 and 2.73, respectively) the toxicity is high, decreasing with the increase of external pH. In addition, the toxicity of identical concentrations of the undissociated acid form is pH independent, as observed with 2,4-dichlorophenol (2,4-DCP), an intermediate of 2,4-D degradation. Consequently, at pH values above 3.5 (approximately one unit higher than 2,4-D pK(a)), 2,4-DCP becomes more toxic than the original herbicide. A dose-dependent inhibition of growth kinetics and increased duration of growth latency is observed following sudden exposure of an unadapted yeast cell population to the presence of the herbicides. This contrasts with the effect of 2,4-DCP, which essentially affects growth kinetics. Experimental evidences suggest that the acid herbicides toxicity is not exclusively dependent on the liposolubility of the toxic form, as may essentially be the case of 2,4-DCP. An unadapted yeast cell population at the early stationary-phase of growth under nutrient limitation is significantly more resistant to short-term herbicide induced death than an exponential-phase population. Consequently, the duration of growth latency is reduced, as observed with the increase of the size of the herbicide stressed population. However, these physiological parameters have no significant effect either on growth kinetics, following growth resumption under herbicide stress, or on the growth curve of yeast cells previously adapted to the herbicides, indicating that their role is exerted at the level of cell adaptation. PMID:12586155

  13. Origin of subdiffusion of water molecules on cell membrane surfaces

    CERN Document Server

    Yamamoto, Eiji; Yasui, Masato; Yasuoka, Kenji

    2014-01-01

    Water molecules play an important role in providing unique environments for biological reactions on cell membranes. It is widely believed that water molecules form bridges that connect lipid molecules and stabilize cell membranes. Using all-atom molecular dynamics simulations, we show that translational and rotational diffusion of water molecules on lipid membrane surfaces exhibit subdiffusion. Moreover, we provide evidence that both divergent mean trapping time (continuous-time random walk) and long-correlated noise (fractional Brownian motion) contribute to this subdiffusion. These results suggest that subdiffusion on cell membranes causes the water retardation, an enhancement of cell membrane stability, and a higher reaction efficiency.

  14. Surface display and bioactivity of Bombyx mori acetylcholinesterase on Pichia pastoris

    Science.gov (United States)

    To construct the Pichia pastoris (P. pastoris) cell surface display system of Bombyx mori acetylcholinesterase (BmAChE), the gene for the anchor protein (AGa1) was obtained from Saccharomyces cerevisiae and was fused with the modified Bombyx mori acetylcholinesterase gene (bmace) and transformed int...

  15. Investigation of the Cell Surface Proteome of Human Periodontal Ligament Stem Cells.

    Science.gov (United States)

    Xiong, Jimin; Menicanin, Danijela; Zilm, Peter S; Marino, Victor; Bartold, P Mark; Gronthos, Stan

    2016-01-01

    The present study examined the cell surface proteome of human periodontal ligament stem cells (PDLSC) compared to human fibroblasts. Cell surface proteins were prelabelled with CyDye before processing to extract the membrane lysates, which were separated using 2D electrophoresis. Selected differentially expressed protein "spots" were identified using Mass spectrometry. Four proteins were selected for validation: CD73, CD90, Annexin A2, and sphingosine kinase 1 previously associated with mesenchymal stem cells. Flow cytometric analysis found that CD73 and CD90 were highly expressed by human PDLSC and gingival fibroblasts but not by keratinocytes, indicating that these antigens could be used as potential markers for distinguishing between mesenchymal cells and epithelial cell populations. Annexin A2 was also found to be expressed at low copy number on the cell surface of human PDLSC and gingival fibroblasts, while human keratinocytes lacked any cell surface expression of Annexin A2. In contrast, sphingosine kinase 1 expression was detected in all the cell types examined using immunocytochemical analysis. These proteomic studies form the foundation to further define the cell surface protein expression profile of PDLSC in order to better characterise this cell population and help develop novel strategies for the purification of this stem cell population. PMID:27579043

  16. Lipid rafts: cell surface platforms for T cell signaling

    Directory of Open Access Journals (Sweden)

    TONY MAGEE

    2002-01-01

    Full Text Available The Src family tyrosine kinase Lck is essential for T cell development and T cell receptor (TCR* signaling. Lck is post-translationally fatty acylated at its N-terminus conferring membrane targeting and concentration in plasma membrane lipid rafts, which are lipid-based organisational platforms. Confocal fluorescence microscopy shows that Lck colocalises in rafts with GPI-linked proteins, the adaptor protein LAT and Ras, but not with non-raft membrane proteins including the protein tyrosine phosphatase CD45. The TCR also associates with lipid rafts and its cross-linking causes coaggregation of raft-associated proteins including Lck, but not of CD45. Cross-linking of either the TCR or rafts strongly induces specific tyrosine phosphorylation of the TCR in the rafts. Remarkably, raft patching alone induces signalling events analogous to TCR stimulation, with the same dependence on expression of key TCR signalling molecules. Our results indicate a mechanism whereby TCR engagement promotes aggregation of lipid rafts, which facilitates colocalisation of signaling proteins including Lck, LAT, and the TCR, while excluding CD45, thereby potentiating protein tyrosine phosphorylation and downstream signaling. We are currently testing this hypothesis as well as using imaging techniques such as fluorescence resonance energy transfer (FRET microscopy to study the dynamics of proteins and lipids in lipid rafts in living cells undergoing signaling events. Recent data show that the key phosphoinositide PI(4,5P2 is concentrated in T cell lipid rafts and that on stimulation of the cells it is rapidly converted to PI(3,4,5P3 and diacylglycerol within rafts. Thus rafts are hotspots for both protein and lipid signalling pathways.

  17. Adhesion defective BHK cell mutant has cell surface heparan sulfate proteoglycan of altered properties

    DEFF Research Database (Denmark)

    Couchman, J R; Austria, R; Woods, A; Hughes, R C

    1988-01-01

    In the light of accumulating data that implicate cell surface heparan sulfate proteoglycans (HSPGs) with a role in cell interactions with extracellular matrix molecules such as fibronectin, we have compared the properties of these molecules in wild-type BHK cells and an adhesion-defective ricin......-resistant mutant (RicR14). Our results showed that the mutant, unlike BHK cells, cannot form focal adhesions when adherent to planar substrates in the presence of serum. Furthermore, while both cell lines possess similar amounts of cell surface HSPG with hydrophobic properties, that of RicR14 cells had decreased...... sulfation, reduced affinity for fibronectin and decreased half-life on the cell surface when compared to the normal counterpart. Our conclusions based on this data are that these altered properties may, in part, account for the adhesion defect in the ricin-resistant mutant. Whether this results from the...

  18. The cell surface expressed nucleolin is a glycoprotein that triggers calcium entry into mammalian cells

    International Nuclear Information System (INIS)

    Nucleolin is an ubiquitous nucleolar phosphoprotein involved in fundamental aspects of transcription regulation, cell proliferation and growth. It has also been described as a shuttling molecule between nucleus, cytosol and the cell surface. Several studies have demonstrated that surface nucleolin serves as a receptor for various extracellular ligands implicated in cell proliferation, differentiation, adhesion, mitogenesis and angiogenesis. Previously, we reported that nucleolin in the extranuclear cell compartment is a glycoprotein containing N- and O-glycans. In the present study, we show that glycosylation is an essential requirement for surface nucleolin expression, since it is prevented when cells are cultured in the presence of tunicamycin, an inhibitor of N-glycosylation. Accordingly, surface but not nuclear nucleolin is radioactively labeled upon metabolic labeling of cells with [3H]glucosamine. Besides its well-demonstrated role in the internalization of specific ligands, here we show that ligand binding to surface nucleolin could also induce Ca2+ entry into cells. Indeed, by flow cytometry, microscopy and patch-clamp experiments, we show that the HB-19 pseudopeptide, which binds specifically surface nucleolin, triggers rapid and intense membrane Ca2+ fluxes in various types of cells. The use of several drugs then indicated that Store-Operated Ca2+ Entry (SOCE)-like channels are involved in the generation of these fluxes. Taken together, our findings suggest that binding of an extracellular ligand to surface nucleolin could be involved in the activation of signaling pathways by promoting Ca2+ entry into cells

  19. Enhanced cell attachment using a novel cell culture surface presenting functional domains from extracellular matrix proteins

    OpenAIRE

    Cooke, M. J.; Phillips, S R; Shah, D. S. H.; Athey, D.; Lakey, J H; Przyborski, S A

    2008-01-01

    Many factors contribute to the creation and maintenance of a realistic environment for cell growth in vitro, e.g. the consistency of the growth medium, the addition of supplements, and the surface on which the cells grow. The nature of the surface on which cells are cultured plays an important role in their ability to attach, proliferate, migrate and function. Components of the extracellular matrix (ECM) are often used to coat glass or plastic surfaces to enhance cell attachment in vitro. Fra...

  20. Stress Tolerance Variations in Saccharomyces cerevisiae Strains from Diverse Ecological Sources and Geographical Locations.

    Directory of Open Access Journals (Sweden)

    Yan-Lin Zheng

    Full Text Available The budding yeast Saccharomyces cerevisiae is a platform organism for bioethanol production from various feedstocks and robust strains are desirable for efficient fermentation because yeast cells inevitably encounter stressors during the process. Recently, diverse S. cerevisiae lineages were identified, which provided novel resources for understanding stress tolerance variations and related shaping factors in the yeast. This study characterized the tolerance of diverse S. cerevisiae strains to the stressors of high ethanol concentrations, temperature shocks, and osmotic stress. The results showed that the isolates from human-associated environments overall presented a higher level of stress tolerance compared with those from forests spared anthropogenic influences. Statistical analyses indicated that the variations of stress tolerance were significantly correlated with both ecological sources and geographical locations of the strains. This study provides guidelines for selection of robust S. cerevisiae strains for bioethanol production from nature.

  1. Determinants of Swe1p Degradation in Saccharomyces cerevisiae

    OpenAIRE

    McMillan, John N.; Theesfeld, Chandra L.; Harrison, Jacob C.; Bardes, Elaine S.G.; Lew, Daniel J.

    2002-01-01

    Swe1p, the sole Wee1-family kinase in Saccharomyces cerevisiae, is synthesized during late G1 and is then degraded as cells proceed through the cell cycle. However, Swe1p degradation is halted by the morphogenesis checkpoint, which responds to insults that perturb bud formation. The Swe1p stabilization promotes cell cycle arrest through Swe1p-mediated inhibitory phosphorylation of Cdc28p until the cells can recover from the perturbation and resume bud formation. Swe1p degradation involves the...

  2. Cell surface polypeptides of murine T-cell clones expressing cytolytic or amplifier activity.

    OpenAIRE

    Sarmiento, M.; Glasebrook, A L; Fitch, F. W.

    1980-01-01

    Murine cytolytic T-cell and amplifier T-cell clones derived from secondary unidirectional mixed leukocyte cultures were labeled with 125I by the lactoperoxidase method and their polypeptide profiles were analyzed by NaDodSO4/polyacrylamide gel electrophoresis. All cytolytic T-cell clones derived from the same mouse strain yeilded similar cell surface polypeptide profiles. However, profiles obtained with three amplifier T-cell clones were strikingly different from each other as well as from th...

  3. L-Histidine inhibits biofilm formation and FLO11- associated phenotypes in Saccharomyces cerevisiae flor yeasts

    OpenAIRE

    Bou Zeidan, Marc; Zara, Giacomo; Viti, Carlo; Decorosi, Francesca; Mannazzu, Ilaria Maria; Budroni, Marilena; Giovannetti, Luciana; Zara, Severino

    2014-01-01

    Flor yeasts of Saccharomyces cerevisiae have an innate diversity of FLO11 which codes for a highly hydrophobic and anionic cell-wall glycoprotein with a fundamental role in biofilm formation. In this study, 380 nitrogen compounds were administered to three S. cerevisiae flor strains handling FLO11 alleles with different expression levels. S. cerevisiae strain S288c was used as the reference strain as it cannot produce FLO11p. The flor strains generally metabolized amino acids and dipeptides a...

  4. Relationships between cell surface insulin binding and endocytosis in adipocytes

    International Nuclear Information System (INIS)

    Chymotrypsin substrate analogues, such as N-acetyl-Tyr ethyl ester, have recently been demonstrated to inhibit the endocytic uptake of insulin in isolated rat adipocytes. In this study, the effect of N-acetyl-Tyr ethyl ester on cell surface insulin binding and dissociation were examined. Surface-bound 125I-insulin was distinguished from intracellular 125I-insulin by the sensitivity of the former to rapid dissociation with an acidic buffer. Plateau levels of surface-bound insulin at 37 degree C were increased 70% by inhibiting the internalization pathway. This increase was temperature and insulin concentration dependent. Thus differences in surface binding were small at 12 degree C and also at high insulin concentrations. Inhibition of internalization with N-acetyl-Tyr ethyl ester markedly slowed the loss of surface-bound insulin observed during dissociation the loss of surface-bound insulin observed during dissociation studies. After 20-30 min of dissociation, the remaining levels of surface-bound insulin were three- to fourfold higher in treated adipocytes compared with control adipocytes. Added unlabeled insulin retained its ability to accelerate the dissociation of insulin in N-acetyl-Tyr ethyl ester-treated cells. These observations indicate that the internalization pathway is a quantitatively important factor in determining levels of surface binding at 37 degree C and in determining the rat of deactivation of insulin binding

  5. Differential inactivation analysis of diploid yeast exposed to radiation of various LET. I. Computerized single-cell observation and preliminary application to x-ray-treated Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    This series of investigations was designed to observe growth and division of single, diploid yeast cells within the first four generations after irradiation with ionizing radiation. Evidence exists that cell reactions important for the final cell fate occur during this period, and therefore the analysis of cell kinetics and of stationary forms of inactivated cells can be performed. A large number of experiments is necessary to obtain statistically confirmed results of single-cell observation. An automatically steered microphotographic registration device has been developed to facilitate the collection of large numbers of observations. Optical data scanned by a TV camera and digitally stored in a computer are processed by pattern recognizing programs to achieve the correct correlation of newly built cells to existing ones and to deliver a pedigree over four generations of at least eight cells for every irradiated single cell. The pooled data of many pedigrees of this kind allow the analysis of the differential behavior of a total population. From the analysis of x-irradiated cells one can conclude that a single cell that produces at least a microcolony of five cells is eventually able to form a macrocolony and thus can be considered a survivor. That means the division probability of cells to go from generation zero to three corresponds to the survival curve of the colony-forming ability test. Therefore this method is suitable for the differential description of the important phenomenological cell reactions after irradiation

  6. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity

    DEFF Research Database (Denmark)

    Jensen, Helle; Andresen, Lars; Hansen, Karen Aagaard; Skov, Søren

    2009-01-01

    We show that inhibition of HDAC activity leads to surface expression of Hsp70 on various hematopoietic cancer cells, an occurance that was not observed on naïve or activated peripheral blood cells. HDAC inhibitor-mediated Hsp70 surface expression was confined to the apoptotic Annexin V...... activity selectively induces surface expression of Hsp70 on hematopoietic cancer cells and that this may increase immunorecognition of these cells.......-positive cells and blocked by inhibition of apoptosis. Other chemotherapeutic inducers of apoptosis such as etoposide and camptothecin also led to a robust induction of Hsp70 surface expression. Hsp70 expression was, however, not caused by induction of apoptosis per se, as activated CD4 T cells remained Hsp70...

  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 ...... result of the adaptation. Determination of the level of mRNA encoding aprotinin and the plasmid copy number pointed to different mechanisms responsible for the decline in aprotinin yield in the different strains. (C) 2008 Elsevier B.V. All rights reserved....

  8. Regulation of Maltose Transport and Metabolism in Saccharomyces cerevisiae

    OpenAIRE

    Novak, Srđan; Zechner-Krpan, Vesna; Marić, Vladimir

    2004-01-01

    Maltose metabolism in the yeast Saccharomyces cerevisiae is of great importance both for academic and industrial researchers. It requires the presence of at least one of five independent MAL loci: MAL1, MAL2, MAL3, MAL4 and MAL6. Each active locus is made of three genes: two structural genes that encode intracellular enzyme maltase and transport protein for maltose, and the third gene that encodes positive regulatory protein. Maltose is transported unchanged into the cell with the help of spe...

  9. A novel selection system for chromosome translocations in Saccharomyces cerevisiae.

    OpenAIRE

    Tennyson, Rachel B; Ebran, Nathalie; Herrera, Anissa E; Lindsley, Janet E.

    2002-01-01

    Chromosomal translocations are common genetic abnormalities found in both leukemias and solid tumors. While much has been learned about the effects of specific translocations on cell proliferation, much less is known about what causes these chromosome rearrangements. This article describes the development and use of a system that genetically selects for rare translocation events using the yeast Saccharomyces cerevisiae. A translocation YAC was created that contains the breakpoint cluster regi...

  10. Immunogold labels: cell-surface markers in atomic force microscopy

    OpenAIRE

    Putman, Constant A.J.; Grooth, de, B.G.; Hansma, Paul K.; Hulst, van der, R.W.M.; Greve, Jan

    1993-01-01

    The feasibility of using immunogold labels as cell-surface markers in atomic force microscopy is shown in this paper. The atomic force microscope (AFM) was used to image the surface of immunogold-labeled human lymphocytes. The lymphocytes were isolated from whole blood and labeled by an indirect immunolabeling method using the monoclonal antibody anti-CD3 and a secondary antibody (Goat-anti-Mouse) linked to 30 nm colloidal gold particles. Some of the samples were enhanced by silver deposition...

  11. Catalytic activity of baker's yeast in a mediatorless microbial fuel cell.

    Science.gov (United States)

    Sayed, Enas Taha; Tsujiguchi, Takuya; Nakagawa, Nobuyoshi

    2012-08-01

    The catalytic activity of baker's yeast, Saccharomyces cerevisiae, as a biocatalyst was investigated in a mediatorless microbial fuel cell. The yeast cells that adhered on the anode surface were the active biocatalyst for glucose oxidation in a mediatorless biofuel cell, suggesting that the electron transfer took place through the surface confined species. The species in the anolyte solution including the dispersed yeast cells did not take a part in the electron transfer and thus in the power generation. PMID:22357359

  12. Detection of Merkel cell polyomavirus on environmental surfaces

    OpenAIRE

    Foulongne, Vincent; Courgnaud, Valérie; Champeau, William; Segondy, Michel

    2011-01-01

    Abstract The Merkel cell polyomavirus (MCPyV) is a human virus identifed recently which is associated with the Merkel cell carcinoma. This virus is also detected frequently in the skin of healthy individuals. The presence of MCPyV has been investigated on environmental surfaces in contact with human skin. Various surfaces in 4 laboratories, public places, and individual homes were swabbed. Human DNA and MCPyV DNA were detected in swabs by real-time PCR. MCPyV DNA levels were measu...

  13. Tetraploid cells from cytokinesis failure induce aneuploidy and spontaneous transformation of mouse ovarian surface epithelial cells

    OpenAIRE

    Lv, Lei; Zhang, Tianwei; Yi, Qiyi; Huang, Yun; Wang, Zheng; Hou, Heli; Zhang, Huan; Zheng, Wei; Hao, Qiaomei; Guo, Zongyou; Howard J Cooke; Shi, Qinghua

    2012-01-01

    Most ovarian cancers originate from the ovarian surface epithelium and are characterized by aneuploid karyotypes. Aneuploidy, a consequence of chromosome instability, is an early event during the development of ovarian cancers. However, how aneuploid cells are evolved from normal diploid cells in ovarian cancers remains unknown. In the present study, cytogenetic analyses of a mouse syngeneic ovarian cancer model revealed that diploid mouse ovarian surface epithelial cells (MOSECs) experienced...

  14. An electrochemical surface plasmon resonance imaging system targeting cell analysis

    Science.gov (United States)

    Zhang, L. L.; Chen, X.; Wei, H. T.; Li, H.; Sun, J. H.; Cai, H. Y.; Chen, J. L.; Cui, D. F.

    2013-08-01

    This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 μm × 10 μm and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously.

  15. The Role of Surface Receptor Density in Surface-Initiated Polymerizations for Cancer Cell Isolation.

    Science.gov (United States)

    Lilly, Jacob L; Berron, Brad J

    2016-06-01

    Fluid biopsies potentially offer a minimally invasive alternative to traditional tissue biopsies for the continual monitoring of metastatic cancer. Current established technologies for isolating circulating tumor cells (CTCs) suffer from poor purity and yield and require fixatives that preclude the collection of viable cells for longitudinal analyses of biological function. Antigen specific lysis (ASL) is a rapid, high-purity method of cell isolation based on targeted protective coatings on antigen-presenting cells and lysis depletion of unprotected antigen-negative cells. In ASL, photoinitiators are specifically labeled on cell surfaces that enable subsequent surface-initiated polymerization. Critically, the significant determinants of process yield have yet to be investigated for this emerging technology. In this work, we show that the labeling density of photoinitiators is strongly correlated with the yield of intact cells during ASL by flow cytometry analysis. Results suggest ASL is capable of delivering ∼25% of targeted cells after isolation using traditional antibody labeling approaches. Monomer formulations of two molecular weights of PEG-diacrylate (Mn ∼ 575 and 3500) are examined. The gelation response during ASL polymerization is also investigated via protein microarray analogues on planar glass. Finally, a density threshold of photoinitiator labeling required for protection during lysis is determined for both monomer formulations. These results indicate ASL is a promising technology for high yield CTC isolation for rare-cell function assays and fluid biopsies. PMID:27206735

  16. Surface-enhanced Raman spectroscopy of the endothelial cell membrane.

    Directory of Open Access Journals (Sweden)

    Simon W Fogarty

    Full Text Available We applied surface-enhanced Raman spectroscopy (SERS to cationic gold-labeled endothelial cells to derive SERS-enhanced spectra of the bimolecular makeup of the plasma membrane. A two-step protocol with cationic charged gold nanoparticles followed by silver-intensification to generate silver nanoparticles on the cell surface was employed. This protocol of post-labelling silver-intensification facilitates the collection of SERS-enhanced spectra from the cell membrane without contribution from conjugated antibodies or other molecules. This approach generated a 100-fold SERS-enhancement of the spectral signal. The SERS spectra exhibited many vibrational peaks that can be assigned to components of the cell membrane. We were able to carry out spectral mapping using some of the enhanced wavenumbers. Significantly, the spectral maps suggest the distribution of some membrane components are was not evenly distributed over the cells plasma membrane. These results provide some possible evidence for the existence of lipid rafts in the plasma membrane and show that SERS has great potential for the study and characterization of cell surfaces.

  17. Surface plasmon resonance imaging of cells and surface-associated fibronectin

    Directory of Open Access Journals (Sweden)

    Bhadriraju Kiran

    2009-02-01

    Full Text Available Abstract Background A critical challenge in cell biology is quantifying the interactions of cells with their extracellular matrix (ECM environment and the active remodeling by cells of their ECM. Fluorescence microscopy is a commonly employed technique for examining cell-matrix interactions. A label-free imaging method would provide an alternative that would eliminate the requirement of transfected cells and modified biological molecules, and if collected nondestructively, would allow long term observation and analysis of live cells. Results Using surface plasmon resonance imaging (SPRI, the deposition of protein by vascular smooth muscle cells (vSMC cultured on fibronectin was quantified as a function of cell density and distance from the cell periphery. We observed that as much as 120 ng/cm2 of protein was deposited by cells in 24 h. Conclusion SPRI is a real-time, low-light-level, label-free imaging technique that allows the simultaneous observation and quantification of protein layers and cellular features. This technique is compatible with live cells such that it is possible to monitor cellular modifications to the extracellular matrix in real-time.

  18. Characterization of cell-surface determinants important for baculovirus infection.

    Science.gov (United States)

    Tani, H; Nishijima, M; Ushijima, H; Miyamura, T; Matsuura, Y

    2001-01-01

    Baculovirus gp64 envelope glycoprotein is a major component of the envelope of the budded virus and is involved in virus entry into the host cells by endocytosis. To investigate the cell-surface molecules important for infection of baculovirus into mammalian cells, we constructed a recombinant baculovirus, Ac64-CAluc, which has gp64 and luciferase genes under the polyhedrin and the CAG promoter, respectively. For controls, we constructed recombinant viruses possessing vesicular stomatitis virus (VSV) G protein, mouse hepatitis virus (MHV) S protein, or green fluorescent protein (GFP) gene under the polyhedrin promoter and the luciferase gene under the CAG promoter (AcVSVG-CAluc, AcMHVS-CAluc, and AcGFP-CAluc). Treatment of HepG2 cells with phospholipase C markedly reduced the reporter gene expression by Ac64-CAluc or AcVSVG-CAluc in a dose-dependent manner, whereas AcMHVS-CAluc was shown to be resistant to the treatment. Inhibition with purified lipids and susceptibility to the mutant CHO hamster cell lines deficient in phospholipids synthesis suggest that the interaction of gp64 and phospholipids on the cell surface might play an important role in baculovirus infection into mammalian cells. PMID:11145915

  19. Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: Regulatory roles of cell surface glycans

    OpenAIRE

    Suzuki, Osamu; Abe, Masafumi

    2014-01-01

    Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic ac...

  20. Multijunction Solar Cells Optimized for the Mars Surface Solar Spectrum

    Science.gov (United States)

    Edmondson, Kenneth M.; Fetzer, Chris; Karam, Nasser H.; Stella, Paul; Mardesich, Nick; Mueller, Robert

    2007-01-01

    This paper gives an update on the performance of the Mars Exploration Rovers (MER) which have been continually performing for more than 3 years beyond their original 90-day missions. The paper also gives the latest results on the optimization of a multijunction solar cell that is optimized to give more power on the surface of Mars.

  1. Progress in Metabolic Engineering of Saccharomyces cerevisiae

    OpenAIRE

    Nevoigt, Elke

    2008-01-01

    Summary: The traditional use of the yeast Saccharomyces cerevisiae in alcoholic fermentation has, over time, resulted in substantial accumulated knowledge concerning genetics, physiology, and biochemistry as well as genetic engineering and fermentation technologies. S. cerevisiae has become a platform organism for developing metabolic engineering strategies, methods, and tools. The current review discusses the relevance of several engineering strategies, such as rational and inverse metabolic...

  2. Influence of the propagation strategy for obtaining robust Saccharomyces cerevisiae cells that efficiently co-ferment xylose and glucose in lignocellulosic hydrolysates

    OpenAIRE

    Tomás-Pejó, Elia; Olsson, Lisbeth

    2015-01-01

    Development of xylose-fermenting yeast strains that are tolerant to the inhibitors present in lignocellulosic hydrolysates is crucial to achieve efficient bioethanol production processes. In this study, the importance of the propagation strategy for obtaining robust cells was studied. Addition of hydrolysate during propagation of the cells adapted them to the inhibitors, resulting in more tolerant cells with shorter lag phases and higher specific growth rates in minimal medium containing acet...

  3. Rear surface passivation in buried contact solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Y.H.; Dai, X.M.; Zhao, J.H.; Wang, A.H.; Wenham, S.R.; Honsberg, C.B. [Univ. of New South Wales, Sydney, New South Wales (Australia). Photovoltaic Special Research Centre

    1997-12-31

    A range of rear surface structures have been developed and studied for the purpose of improving the performance of buried contact solar cells (BCSC). In particular, improved results are reported for the double grooved BCSC with oxidized p-type rear surface, with V{sub oc} of 685 mV having been demonstrated. The importance of including an alneal treatment is clearly evident with open circuit voltages typically degrading 60 mV without its inclusion. Devices with the same structure but with a rear floating junction are also evaluated within the study and again the dependence on an alneal is evident for cells with low surface phosphorus concentration. In the highest voltage devices, the rear boron diffused grooves contribute almost 30% of the total device dark saturation current, with test devices achieving V{sub oc} as high as 694 mV for a BCSC with the rear grooves replaced by photolithographically defined boron diffused contact regions.

  4. Methods To Identify Aptamers against Cell Surface Biomarkers

    Directory of Open Access Journals (Sweden)

    Frédéric Ducongé

    2011-09-01

    Full Text Available Aptamers are nucleic acid-based ligands identified through a process of molecular evolution named SELEX (Systematic Evolution of Ligands by Exponential enrichment. During the last 10-15 years, numerous aptamers have been developed specifically against targets present on or associated with the surface of human cells or infectious pathogens such as viruses, bacteria, fungi or parasites. Several of the aptamers have been described as potent probes, rivalling antibodies, for use in flow cytometry or microscopy. Some have also been used as drugs by inhibiting or activating functions of their targets in a manner similar to neutralizing or agonistic antibodies. Additionally, it is straightforward to conjugate aptamers to other agents without losing their affinity and they have successfully been used in vitro and in vivo to deliver drugs, siRNA, nanoparticles or contrast agents to target cells. Hence, aptamers identified against cell surface biomarkers represent a promising class of ligands. This review presents the different strategies of SELEX that have been developed to identify aptamers for cell surface-associated proteins as well as some of the methods that are used to study their binding on living cells.

  5. Regulation of Lactobacillus plantarum contamination on the carbohydrate and energy related metabolisms of Saccharomyces cerevisiae during bioethanol fermentation.

    Science.gov (United States)

    Dong, Shi-Jun; Lin, Xiang-Hua; Li, Hao

    2015-11-01

    During the industrial bioethanol fermentation, Saccharomyces cerevisiae cells are often stressed by bacterial contaminants, especially lactic acid bacteria. Generally, lactic acid bacteria contamination can inhibit S. cerevisiae cell growth through secreting lactic acid and competing with yeast cells for micronutrients and living space. However, whether are there still any other influences of lactic acid bacteria on yeast or not? In this study, Lactobacillus plantarum ATCC 8014 was co-cultivated with S. cerevisiae S288c to mimic the L. plantarum contamination in industrial bioethanol fermentation. The contaminative L. plantarum-associated expression changes of genes involved in carbohydrate and energy related metabolisms in S. cerevisiae cells were determined by quantitative real-time polymerase chain reaction to evaluate the influence of L. plantarum on carbon source utilization and energy related metabolism in yeast cells during bioethanol fermentation. Contaminative L. plantarum influenced the expression of most of genes which are responsible for encoding key enzymes involved in glucose related metabolisms in S. cerevisiae. Specific for, contaminated L. plantarum inhibited EMP pathway but promoted TCA cycle, glyoxylate cycle, HMP, glycerol synthesis pathway, and redox pathway in S. cerevisiae cells. In the presence of L. plantarum, the carbon flux in S. cerevisiae cells was redistributed from fermentation to respiratory and more reducing power was produced to deal with the excess NADH. Moreover, L. plantarum contamination might confer higher ethanol tolerance to yeast cells through promoting accumulation of glycerol. These results also highlighted our knowledge about relationship between contaminative lactic acid bacteria and S. cerevisiae during bioethanol fermentation. PMID:26279142

  6. Cell adhesion on Ti surface with controlled roughness

    Energy Technology Data Exchange (ETDEWEB)

    Burgos-Asperilla, L.; Garcia-Alonso, M. C.; Escudero, M. L.; Alonso, C.

    2015-07-01

    In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10{sup -}3 min{sup -}1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days), due to the presence of amino acids and proteins from the culture medium that have been adsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti. (Author)

  7. Surfome analysis of a wild-type wine Saccharomyces cerevisiae strain.

    Science.gov (United States)

    Braconi, Daniela; Amato, Loredana; Bernardini, Giulia; Arena, Simona; Orlandini, Maurizio; Scaloni, Andrea; Santucci, Annalisa

    2011-09-01

    The yeast Saccharomyces cerevisiae, besides being an eukaryotic cell model, plays a fundamental role in the production of fermented foods. In the winemaking industry, yeast cell walls may be involved in numerous processes and contribute substantially to the final chemical and sensorial profiles of wines. Nonetheless, apart from mannoproteins, little is known on the protein components of the yeast cell wall and their changes during the fermentation of must into wine. In this work, we performed a dynamic analysis of the cell surface proteome (surfome) of an autochthonous wine yeast strain (previously selected as a wine fermentation starter) by shaving intact cells with trypsin and identifying tryptic peptides by means of nLC-ESI-LIT-MS/MS. Out of the 42 identified proteins, 16 and 14 were found to be specifically expressed in wine yeast surfome at the beginning and at the end of fermentation, respectively. The molecular functions of these specifically expressed proteins might help in explaining their roles in the cell wall as a response to the alcoholic fermentation-related stresses. Additionally, we provided the identification of 20 new potential cell wall related proteins. Globally, our results might provide new useful data for the selection and characterization of yeast strains to be used in the winemaking industry. PMID:21645823

  8. Membrane Protein Production in the Yeast, S. cerevisiae.

    Science.gov (United States)

    Cartwright, Stephanie P; Mikaliunaite, Lina; Bill, Roslyn M

    2016-01-01

    The first crystal structures of recombinant mammalian membrane proteins were solved in 2005 using protein that had been produced in yeast cells. One of these, the rabbit Ca(2+)-ATPase SERCA1a, was synthesized in Saccharomyces cerevisiae. All host systems have their specific advantages and disadvantages, but yeast has remained a consistently popular choice in the eukaryotic membrane protein field because it is quick, easy and cheap to culture, whilst being able to post-translationally process eukaryotic membrane proteins. Very recent structures of recombinant membrane proteins produced in S. cerevisiae include those of the Arabidopsis thaliana NRT1.1 nitrate transporter and the fungal plant pathogen lipid scramblase, TMEM16. This chapter provides an overview of the methodological approaches underpinning these successes. PMID:27485327

  9. Advanced biofuel production by the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Buijs, Nicolaas A; Siewers, Verena; Nielsen, Jens

    2013-06-01

    Replacement of conventional transportation fuels with biofuels will require production of compounds that can cover the complete fuel spectrum, ranging from gasoline to kerosene. Advanced biofuels are expected to play an important role in replacing fossil fuels because they have improved properties compared with ethanol and some of these may have the energy density required for use in heavy duty vehicles, ships, and aviation. Moreover, advanced biofuels can be used as drop-in fuels in existing internal combustion engines. The yeast cell factory Saccharomyces cerevisiae can be turned into a producer of higher alcohols (1-butanol and isobutanol), sesquiterpenes (farnesene and bisabolene), and fatty acid ethyl esters (biodiesel), and here we discusses progress in metabolic engineering of S. cerevisiae for production of these advanced biofuels. PMID:23628723

  10. Copper oxide nanoparticles inhibit the metabolic activity of Saccharomyces cerevisiae.

    Science.gov (United States)

    Mashock, Michael J; Kappell, Anthony D; Hallaj, Nadia; Hristova, Krassimira R

    2016-01-01

    Copper oxide nanoparticles (CuO NPs) are used increasingly in industrial applications and consumer products and thus may pose risk to human and environmental health. The interaction of CuO NPs with complex media and the impact on cell metabolism when exposed to sublethal concentrations are largely unknown. In the present study, the short-term effects of 2 different sized manufactured CuO NPs on metabolic activity of Saccharomyces cerevisiae were studied. The role of released Cu(2+) during dissolution of NPs in the growth media and the CuO nanostructure were considered. Characterization showed that the 28 nm and 64 nm CuO NPs used in the present study have different primary diameter, similar hydrodynamic diameter, and significantly different concentrations of dissolved Cu(2+) ions in the growth media released from the same initial NP mass. Exposures to CuO NPs or the released Cu(2+) fraction, at doses that do not have impact on cell viability, showed significant inhibition on S. cerevisiae cellular metabolic activity. A greater CuO NP effect on the metabolic activity of S. cerevisiae growth under respiring conditions was observed. Under the tested conditions the observed metabolic inhibition from the NPs was not explained fully by the released Cu ions from the dissolving NPs. PMID:26178758

  11. [Production of β-carotene by metabolically engineered Saccharomyces cerevisiae].

    Science.gov (United States)

    Wang, Beibei; Shi, Mingyu; Wang, Dong; Xu, Jiaoyang; Liu, Yi; Yang, Hongjiang; Dai, Zhubo; Zhang, Xueli

    2014-08-01

    β-carotene has a wide range of application in food, pharmaceutical and cosmetic industries. For microbial production of β-carotene in Saccharomyces cerevisiae, the supply of geranylgeranyl diphosphate (GGPP) was firstly increased in S. cerevisiae BY4742 to obtain strain BY4742-T2 through over-expressing truncated 3-hydroxy-3-methylglutaryl-CoA reductase (tHMGR), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, and GGPP synthase (GGPS), which is a key enzyme in the diterpenoid synthetic pathway. The β-carotene synthetic genes of Pantoea agglomerans and Xanthophyllomyces dendrorhous were further integrated into strain BY4742-T2 for comparing β-carotene production. Over-expression of tHMGR and GGPS genes led to 26.0-fold increase of β-carotene production. In addition, genes from X. dendrorhous was more efficient than those from P. agglomerans for β-carotene production in S. cerevisiae. Strain BW02 was obtained which produced 1.56 mg/g (dry cell weight) β-carotene, which could be used further for constructing cell factories for β-carotene production. PMID:25507473

  12. Switching the mode of sucrose utilization by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Miletti Luiz C

    2008-02-01

    Full Text Available 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 sucrose consumption rates are controlled by the external addition of sugar aiming at its low concentrations in the fermentor, is the classical bioprocessing alternative to prevent sugar fermentation by yeasts. However, fed-batch fermentations present drawbacks that could be overcome by simpler batch cultures at relatively high (e.g. 20 g/L initial sugar concentrations. In this study, a S. cerevisiae strain lacking invertase activity was engineered to transport sucrose into the cells through a low-affinity and low-capacity sucrose-H+ symport activity, and the growth kinetics and biomass yields on sucrose analyzed using simple batch cultures. Results We have deleted from the genome of a S. cerevisiae strain lacking invertase the high-affinity sucrose-H+ symporter encoded by the AGT1 gene. This strain could still grow efficiently on sucrose due to a low-affinity and low-capacity sucrose-H+ symport activity mediated by the MALx1 maltose permeases, and its further intracellular hydrolysis by cytoplasmic maltases. Although sucrose consumption by this engineered yeast strain was slower than with the parental yeast strain, the cells grew efficiently on sucrose due to an increased respiration of the carbon source. Consequently, this engineered yeast strain produced less ethanol and 1.5 to 2 times more biomass when cultivated in simple batch mode using 20 g/L sucrose as the carbon source. Conclusion Higher cell densities during batch cultures on 20 g/L sucrose were achieved by using a S. cerevisiae strain engineered in the sucrose uptake system. Such result was accomplished by

  13. MEMS-based dynamic cell-to-cell culture platforms using electrochemical surface modifications

    International Nuclear Information System (INIS)

    MEMS-based biological platforms with the capability of both spatial placements and time releases of living cells for cell-to-cell culture experiments have been designed and demonstrated utilizing electrochemical surface modification effects. The spatial placement is accomplished by electrochemical surface modification of substrate surfaces to be either adhesive or non-adhesive for living cells. The time control is achieved by the electrical activation of the selective indium tin oxide co-culture electrode to allow the migration of living cells onto the electrode to start the cell-to-cell culture studies. Prototype devices have a three-electrode design with an electrode size of 50 × 50 µm2 and the separation gaps of 2 µm between them. An electrical voltage of −1.5 V has been used to activate the electrodes independently and sequentially to demonstrate the dynamic cell-to-cell culture experiments of NIH 3T3 fibroblast and Madin Darby canine kidney cells. As such, this MEMS platform could be a basic yet versatile tool to characterize transient cell-to-cell interactions

  14. 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 that the...... application of the existing methods of genome, transcriptome, proteome and metabolome analysis to other fungi has enormous potential, especially for the production of food and food ingredients. The developments in the past year demonstrate that we have only just started to exploit this potential....

  15. Surface modification of hydrophobic polymers for improvement of endothelial cell-surface interactions

    NARCIS (Netherlands)

    Dekker, A.; Reitsma, K.; Beugeling, T.; Bantjes, A.; Feijen, J.; Kirkpatrick, C.J.; Aken, van W.G.

    1992-01-01

    The aim of this study is to improve the interaction of endothelial cells with polymers used in vascular prostheses. Polytetrafluoroethylene (PTFE; Teflon) films were treated by means of nitrogen and oxygen plasmas. Depending on the plasma exposure time, modified PTFE surfaces showed water-contact an

  16. Real-time detection of cofactor availability in genetically modified living Saccharomyces cerevisiae cells - Simultaneous probing of different geno- and phenotypes

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Heiskanen, Arto; Spegel, C.;

    2009-01-01

    strain, ENY.WA-1A. The developed method is based on multichannel detection using microelectrode arrays. Its versatility was demonstrated by using four microelectrode arrays for simultaneously monitoring the NAD(P)H availability of both geno- and phenotypes under the influence of two different carbon...... sources, glucose and fructose, as well as the cytosolic and mitochondrial inhibitor and uncoupler, dicoumarol. The obtained results indicate that the method is capable of accurately and reproducibly (overall relative standard error of mean 3.2%) mapping the real-time responses of the cells with different...... genotype-phenotype combinations. The ENY.WA cells showed the same response to glucose and fructose when dicoumarol was used; fermentative cells indicated the presence of cytosolic inhibition and respiratory cells a net effect of mitochondrial uncoupling. EBY44 cells showed cytosolic inhibition with the...

  17. Involvement of cell surface phosphatidylinositol-anchored glycoproteins in cell-cell adhesion of chick embryo myoblasts

    OpenAIRE

    1989-01-01

    During myogenesis myoblasts fuse to form multinucleate cells that express muscle-specific proteins. A specific cell-cell adhesion process precedes lipid bilayer union during myoblast fusion (Knudsen, K. A., and A. F. Horwitz. 1977. Dev. Biol. 58:328-338) and is mediated by cell surface glycoproteins (Knudsen, K. A., 1985. J. Cell Biol. 101:891- 897). In this paper we show that myoblast adhesion and myotube formation are inhibited by treating fusion-competent myoblasts with phosphatidylinosito...

  18. Proteomics and glycoproteomics of pluripotent stem-cell surface proteins.

    Science.gov (United States)

    Sun, Bingyun

    2015-03-01

    Pluripotent stem cells are a unique cell type with promising potential in regenerative and personalized medicine. Yet the difficulty to understand and coax their seemingly stochastic differentiation and spontaneous self-renewal have largely limited their clinical applications. A call has been made by numerous researchers for a better characterization of surface proteins on these cells, in search of biomarkers that can dictate developmental stages and lineage specifications, and can help formulate mechanistic insight of stem-cell fate choices. In the past two decades, proteomics has gained significant recognition in profiling surface proteins at high throughput. This review will summarize the impact of these studies on stem-cell biology, and discuss the used proteomic techniques. A systematic comparison of all the techniques and their results is also attempted here to help reveal pros, cons, and the complementarity of the existing methods. This awareness should assist in selecting suitable strategies for stem-cell related research, and shed light on technical improvements that can be explored in the future. PMID:25211708

  19. Compatibility of surface texturization and beam processing of solar cells

    International Nuclear Information System (INIS)

    The use of beam processing, especially pulsed-laser annealing, for junction formation in silicon with texturized surfaces was thought by many to be impossible, because the rapid melting and solidification of the surface cause a rounding of the pyramids, uneven junction formation, and even punch-through of the junction in some areas. Early work by Spire Corporation with e-beam annealing seemed to indicate that extensive rounding of the pyramids was unavoidable when melting occurred. More recently, early attempts at excimer laser annealing of ion-implanted texturized surfaces gave disappointing results. Nevertheless, the recent success of Spire in obtaining 18% AM1 solar cells on texturized surfaces convinced the authors that they should make a more careful study of the compatibility of texturization and beam processing. They report here on the present status of this study

  20. Glycobiology of the cell surface: Its debt to cell electrophoresis 1940-65.

    Science.gov (United States)

    Cook, Geoffrey M W

    2016-06-01

    This Review describes how in the period 1940-1959 cell electrophoresis (in the earlier literature often referred to as 'microelectrophoresis') was used to explore the surface chemistry of cells. Using the erythrocyte as a suitable model for the study of biological membranes, the early investigators were agreed on the presence of negatively charged groups at the surface of this cell. The contemporary dogma was that these were phosphate groups associated with phospholipids. Work in the 1960s, particularly on changes in the electrokinetic properties of erythrocytes following treatment with proteolytic enzymes, lead to the realization that the negatively charged groups at the red cell surface are predominantly due to sialic acids carried on glycoproteins. It quickly became apparent from cell electrophoresis that sialic acids have a ubiquitous presence on the surface of animal cells. This finding required that any complete model of the plasma membrane must include glycosylated molecules at the cell periphery, thus laying the foundations for the field termed 'Glycobiology of the Cell Surface'. PMID:26717803

  1. Surface code—biophysical signals for apoptotic cell clearance

    International Nuclear Information System (INIS)

    Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called ‘find-me’, ‘eat me’ and ‘tolerate me’ signals. Mononuclear phagocytes are attracted by various ‘find-me’ signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via ‘stay away’ signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main ‘eat me’ signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as ‘tolerate me’ signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes. (paper)

  2. 不同菌龄酿酒酵母细胞壁蛋白差异性分析%Diversity Analysis for Different Generation of Saccharomyces cerevisiae Cell Wall Proteins

    Institute of Scientific and Technical Information of China (English)

    成建国; 董亮; 付莹莹; 张利; 郭继强; 赵长新

    2012-01-01

    以酿酒酵母为研究对象,比较了完整细胞提取法、稀碱缓冲液提取法及溶菌酶和β-葡聚糖酶复合酶法等三种酵母菌细胞壁蛋白提取方法,分析了不同菌龄酵母细胞壁差异性蛋白。结果表明:溶菌酶和β-葡聚糖酶复合酶液水解纯化好细胞壁提取蛋白的方法具有所得胞壁蛋白条带较多,且纯度较高的优点,确定了此方法为提取酵母细胞壁蛋白的最佳提取方法。同时,通过SDS-PAGE电泳分析发现,不同菌龄酵母细胞壁蛋白存在着较大的差异性,并确定了分子质量在36 ku、17 ku和12 ku为不同酵母代数细胞壁的3个主要差异性蛋白,其中36 ku、17 ku处条带蛋白随着菌龄的增加酵母细胞壁蛋白表达量逐渐减少,而12 ku处条带蛋白随着菌龄的增加酵母细胞壁蛋白表达量逐渐增加。%In this paper, Saccharomyces cerevisiae cell wall proteins were taken for the application of whole cell extracted from cell wall proteins, dilute alkaline buffer extracted proteins from purified cell wall and Lysozyme and 6- glucanase enzyme solution hydrolysis of purified cell wall to extracted cell wall proteins all this three extraction meth- ods, at the same time. The differences between different algebra yeast cell wall proteins has been identified and ana- lyzed. The results show that:the method of lysozyme and ~-glucanase enzyme solution hydrolysis of purified cell wall to extract cell wall proteins can obtain more cell wall protein bands and higher purity, therefore this method is deter- minted the best extraction method for yeast cell wall protein extraction. Withal, by SDS-PAGE electrophoresis analysis found different generation of yeast cell wall proteins with a large difference and identified molecular weight of 36 kDa, 17 kDa and 12 kDa are the three main different cell wall proteins for different generation yeasts. Among that, the ex- pression of 36 kDa, 17 kDa protein bands decreased with the age of yeast

  3. Surface modified alginate microcapsules for 3D cell culture

    Science.gov (United States)

    Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

    2016-06-01

    Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

  4. Integration of plasma-assisted surface chemical modification, soft lithography, and protein surface activation for single-cell patterning

    Science.gov (United States)

    Cheng, Q.; Komvopoulos, K.

    2010-07-01

    Surface patterning for single-cell culture was accomplished by combining plasma-assisted surface chemical modification, soft lithography, and protein-induced surface activation. Hydrophilic patterns were produced on Parylene C films deposited on glass substrates by oxygen plasma treatment through the windows of polydimethylsiloxane shadow masks. After incubation first with Pluronic F108 solution and then serum medium overnight, surface seeding with mesenchymal stem cells in serum medium resulted in single-cell patterning. The present method provides a means of surface patterning with direct implications in single-cell culture.

  5. Fermentation profile of Saccharomyces cerevisiae and Candida tropicalis as starter cultures on barley malt medium.

    Science.gov (United States)

    Alloue-Boraud, Wazé Aimée Mireille; N'Guessan, Kouadio Florent; Djeni, N'Dédé Théodore; Hiligsmann, Serge; Djè, Koffi Marcellin; Delvigne, Franck

    2015-08-01

    Saccharomyces cerevisiae C8-5 and Candida tropicalis F0-5 isolated from traditional sorghum beer were tested for kinetic parameters on barley malt extract, YPD (863 medium) and for alcohol production. The results showed that C. tropicalis has the highest maximum growth rate and the lowest doubling time. Values were 0.22 and 0.32 h(-1) for maximum growth rate, 3 h 09 min and 2 h 09 min for doubling time respectively on barley malt extract and YPD. On contrary, glucose consumption was the fastest with S. cerevisiae (-0.36 and -0.722 g/l/h respectively on barley malt extract and YPD). When these two yeasts were used as starters in pure culture and co-culture at proportion of 1:1 and 2:1 (cell/cell) for barley malt extract fermentation, we noticed that maltose content increased first from 12.12 g/l to 13.62-16.46 g/l and then decreased. The highest increase was obtained with starter C. tropicalis + S. cerevisiae 2:1. On contrary, glucose content decreased throughout all the fermentation process. For all the starters used, the major part of the ethanol was produced at 16 h of fermentation. Values obtained in the final beers were 11.4, 11.6, 10.4 and 10.9 g/l for fermentation conducted with S. cerevisiae, C. tropicalis, C. tropicalis + S. cerevisiae 1:1 and C. tropicalis + S. cerevisiae 2:1. Cell viability measurement during the fermentation by using flow cytometry revealed that the lowest mean channel fluorescence for FL3 (yeast rate of death) was obtained with C. tropicalis + S. cerevisiae 2:1 after 48 h of fermentation. PMID:26243947

  6. Establishment of cell surface engineering and its development.

    Science.gov (United States)

    Ueda, Mitsuyoshi

    2016-07-01

    Cell surface display of proteins/peptides has been established based on mechanisms of localizing proteins to the cell surface. In contrast to conventional intracellular and extracellular (secretion) expression systems, this method, generally called an arming technology, is particularly effective when using yeasts as a host, because the control of protein folding that is often required for the preparation of proteins can be natural. This technology can be employed for basic and applied research purposes. In this review, I describe various strategies for the construction of engineered yeasts and provide an outline of the diverse applications of this technology to industrial processes such as the production of biofuels and chemicals, as well as bioremediation and health-related processes. Furthermore, this technology is suitable for novel protein engineering and directed evolution through high-throughput screening, because proteins/peptides displayed on the cell surface can be directly analyzed using intact cells without concentration and purification. Functional proteins/peptides with improved or novel functions can be created using this beneficial, powerful, and promising technique. PMID:27305282

  7. Stable isotope labeling of oligosaccharide cell surface antigens

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Silks, L.A. III; Martinez, R.A. [and others

    1998-12-31

    The overall goal of this Laboratory Directed Research and Development (LDRD) project was to develop new methods for synthesis of {sup 13}C-labeled oligosaccharides that are required for nuclear magnetic resonance (NMR) studies of their solution conformation. Oligosaccharides are components of the cell`s outer surface and are involved in important processes such as cell-cell recognition and adhesion. Recently, Danishefsky and coworkers at Slone-Kettering Cancer Center developed a method for the solid-phase chemical synthesis of oligosaccharides. The specific goal of this LDRD project was to prepare uniform {sup 13}C-labeled aldohexose precursors required for the solid-phase synthesis of the Lewis blood-group antigenic determinants. We report the synthesis of {sup 13}C-labeled D-glucal, D-galactal and Fucosyl precursors. We have been collaborating with the Danishefsky group on the synthesis of the Lewis oligosaccharides and the NMR analysis of their solution conformation.

  8. Influence of the propagation strategy for obtaining robust Saccharomyces cerevisiae cells that efficiently co-ferment xylose and glucose in lignocellulosic hydrolysates.

    Science.gov (United States)

    Tomás-Pejó, Elia; Olsson, Lisbeth

    2015-11-01

    Development of xylose-fermenting yeast strains that are tolerant to the inhibitors present in lignocellulosic hydrolysates is crucial to achieve efficient bioethanol production processes. In this study, the importance of the propagation strategy for obtaining robust cells was studied. Addition of hydrolysate during propagation of the cells adapted them to the inhibitors, resulting in more tolerant cells with shorter lag phases and higher specific growth rates in minimal medium containing acetic acid and vanillin than unadapted cells. Addition of hydrolysate during propagation also resulted in cells with better fermentation capabilities. Cells propagated without hydrolysate were unable to consume xylose in wheat straw hydrolysate fermentations, whereas 40.3% and 97.7% of the xylose was consumed when 12% and 23% (v/v) hydrolysate, respectively, was added during propagation. Quantitative polymerase chain reaction revealed changes in gene expression, depending on the concentration of hydrolysate added during propagation. This study highlights the importance of using an appropriate propagation strategy for the optimum performance of yeast in fermentation of lignocellulosic hydrolysates. PMID:25989314

  9. Two programmed replicative lifespans of Saccharomyces cerevisiae formed by the endogenous molecular-cellular network.

    Science.gov (United States)

    Hu, Jie; Zhu, Xiaomei; Wang, Xinan; Yuan, Ruoshi; Zheng, Wei; Xu, Minjuan; Ao, Ping

    2014-12-01

    Cellular replicative capacity is a therapeutic target for regenerative medicine as well as cancer treatment. The mechanism of replicative senescence and cell immortality is still unclear. We investigated the diauxic growth of Saccharomyces cerevisiae and demonstrate that the replicative capacity revealed by the yeast growth curve can be understood by using the dynamical property of the molecular-cellular network regulating S. cerevisiae. The endogenous network we proposed has a limit cycle when pheromone signaling is disabled, consistent with the exponential growth phase with an infinite replicative capacity. In the post-diauxic phase, the cooperative effect of the pheromone activated mitogen-activated protein kinase (MAPK) signaling pathway with the cell cycle leads to a fixed point attractor instead of the limit cycle. The cells stop dividing after several generations counting from the beginning of the post-diauxic growth. By tuning the MAPK pathway, S. cerevisiae therefore programs the number of offsprings it replicates. PMID:24447585

  10. Semiquantitative determination of circulating islet cell surface antibodies in diabetes

    International Nuclear Information System (INIS)

    Circulating pancreatic islet cell antibodies have been demonstrated in patients with insulin-dependent diabetes (IDD). The islet cell surface antibodies (ICSA) were determined by an indirect immunofluorescence test using a suspension of viable islet cells, and similar cytoplasmic antibodies which require the use of group O human pancreas were also found in the serum of some patients. A strong association exists between the presence of islet cell antibodies and the onset of insulin-dependent diabetes. The quantitative determination of circulating ICSA using 125I-protein A, which binds to IgG attached to the islet cell surface, was essentially as described by Lernmark et al. In the present study, we determined the circulating ICSA in diabetes, especially in IDD. The ICSA were estimated in various sera from both indirect immunofluorescence and 125I-protein A. Controls bound 125I-protein A. Sera from 4 IDD patients with circulating ICSA demonstrated by immunofluorescence showed >3,000 cpm 125I-protein A binding activity, and that from 5 patients without ICSA bound <2,000 cpm. Sera from newly-diagnosed diabetics who had severe hyperglycemia showed <2,000 cpm, with or without ICSA. (author)

  11. Cdon, a cell surface protein, mediates oligodendrocyte differentiation and myelination.

    Science.gov (United States)

    Wang, Li-Chun; Almazan, Guillermina

    2016-06-01

    During central nervous system development, oligodendrocyte progenitors (OLPs) establish multiple branched processes and axonal contacts to initiate myelination. A complete understanding of the molecular signals implicated in cell surface interaction to initiate myelination/remyelination is currently lacking. The objective of our study was to assess whether Cdon, a cell surface protein that was shown to participate in muscle and neuron cell development, is involved in oligodendrocyte (OLG) differentiation and myelination. Here, we demonstrate that endogenous Cdon protein is expressed in OLPs, increasing in the early differentiation stages and decreasing in mature OLGs. Immunocytochemistry of endogenous Cdon showed localization on both OLG cell membranes and cellular processes exhibiting puncta- or varicosity-like structures. Cdon knockdown with siRNA decreased protein levels by 62% as well as two myelin-specific proteins, MBP and MAG. Conversely, overexpression of full-length rat Cdon increased myelin proteins in OLGs. The complexity of OLGs branching and contact point numbers with axons were also increased in Cdon overexpressing cells growing alone or in coculture with dorsal root ganglion neurons (DRGNs). Furthermore, myelination of DRGNs was decreased when OLPs were transfected with Cdon siRNA. Altogether, our results suggest that Cdon participates in OLG differentiation and myelination, most likely in the initial stages of development. GLIA 2016;64:1021-1033. PMID:26988125

  12. Low temperature surface passivation for silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Leguijt, C.; Loelgen, P.; Eikelboom, J.A.; Weeber, A.W.; Schuurmans, F.M.; Sinke, W.C. [Netherlands Energy Research Foundation ECN, Petten (Netherlands); Alkemade, P.F.A.; Sarro, P.M. [Delft Institute for MicroElectronics and Submicron Technology DIMES, Delft (Netherlands); Maree, C.H.M. [Department of Atomic and Interface Physics, Debye Institute, University of Utrecht, Utrecht (Netherlands); Verhoef, L.A. [R and S Renewable Energy Systems B.V., Helmond (Netherlands)

    1996-07-18

    Surface passivation at low processing temperatures becomes an important topic for cheap solar cell processing. In this study, we first give a broad overview of the state of the art in this field. Subsequently, the results of a series of mutually related experiments are given about surface passivation with direct Plasma Enhanced Chemical Vapour Deposition (PECVD) of silicon oxide (Si-oxide) and silicon nitride (Si-nitride). Results of harmonically modulated microwave reflection experiments are combined with Capacitance-Voltage measurements on Metal-Insulator-Silicon structures (CV-MIS), accelerated degradation tests and with Secondary Ion Mass Spectrometry (SIMS) and Elastic Recoil Detection (ERD) measurements of hydrogen and deuterium concentrations in the passivating layers. A large positive fixed charge density at the interface is very important for the achieved low surface recombination velocities S. The density of interface states D{sub i}t is strongly reduced by post deposition anneals. The lowest values of S are obtained with PECVD of Si-nitride. The surface passivation obtained with Si-nitride is stable under typical operating conditions for solar cells. By using deuterium as a tracer it is shown that hydrogen in the ambient of the post deposition anneal does not play a role in the passivation by Si-nitride. Finally, the results of CV-MIS measurements on deposited Si-nitride layers are used to calculate effective recombination velocities as a function of the injection level at the surface, using a model that is able to predict the surface recombination velocity S at thermally oxidized silicon surfaces. These results are not in agreement with the measured increase of S at low injection levels

  13. The cell surface organisation of the Notch-1 receptor

    OpenAIRE

    Weisshuhn, Philip Christian; Handford, PA; Redfield, C.

    2014-01-01

    The Notch receptor family plays a key role in development and disease. In cancer, Notch can act either as an oncogene or as a tumour suppressor, and possibly as a cancer stem-cell factor. Whereas most research has focused on downstream signalling events, little is known about the cell surface organisation of Notch and its ligands. The extracellular part of Notch consists mainly of 36 epidermal growth factor-like domains (EGF-domains), many of which bind calcium. Studies have shown that tandem...

  14. Cell-surface acceleration of urokinase-catalyzed receptor cleavage

    DEFF Research Database (Denmark)

    Høyer-Hansen, G; Ploug, M; Behrendt, N;

    1997-01-01

    or indirectly mediated by uPA itself. In a soluble system, uPA can cleave purified uPAR, but the low efficiency of this reaction has raised doubts as to whether uPA is directly responsible for uPAR cleavage on the cells. We now report that uPA-catalyzed cleavage of uPAR on the cell surface is...... strongly favored relative to the reaction in solution. The time course of uPA-catalyzed cleavage of cell-bound uPAR was studied using U937 cells stimulated with phorbol 12-myristate 13-acetate. Only 30 min was required for 10 nM uPA to cleave 50% of the cell-bound uPAR. This uPA-catalyzed cleavage reaction...... was inhibited by a prior incubation of the cells with uPA inactivated by diisopropyl fluorophosphate, demonstrating a requirement for specific receptor binding of the active uPA to obtain the high-efficiency cleavage of cell-bound uPAR. Furthermore, amino-terminal sequence analysis revealed that u...

  15. Formation of nanofilms on cell surfaces to improve the insertion efficiency of a nanoneedle into cells

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Yosuke [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Kawano, Keiko [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-26 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Matsusaki, Michiya; Akashi, Mitsuru [Department of Applied Chemistry, Graduate School of Engineering Science, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nakamura, Noriyuki [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-26 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Nakamura, Chikashi, E-mail: chikashi-nakamura@aist.go.jp [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-26 Naka-cho, Koganei, Tokyo 184-8588 (Japan)

    2012-04-13

    Highlights: Black-Right-Pointing-Pointer We examined the insertion efficiency of nanoneedles into fibroblast and neural cells. Black-Right-Pointing-Pointer Nanofilms formed on cell surfaces improved the insertion efficiency of nanoneedles. Black-Right-Pointing-Pointer Nanofilms improved the insertion efficiency even in Y27632-treated cells. -- Abstract: A nanoneedle, an atomic force microscope (AFM) tip etched to 200 nm in diameter and 10 {mu}m in length, can be inserted into cells with the aid of an AFM and has been used to introduce functional molecules into cells and to analyze intracellular information with minimal cell damage. However, some cell lines have shown low insertion efficiency of the nanoneedle. Improvement in the insertion efficiency of a nanoneedle into such cells is a significant issue for nanoneedle-based cell manipulation and analysis. Here, we have formed nanofilms composed of extracellular matrix molecules on cell surfaces and found that the formation of the nanofilms improved insertion efficiency of a nanoneedle into fibroblast and neural cells. The nanofilms were shown to improve insertion efficiency even in cells in which the formation of actin stress fibers was inhibited by the ROCK inhibitor Y27632, suggesting that the nanofilms with the mesh structure directly contributed to the improved insertion efficiency of a nanoneedle.

  16. Germ Tube Formation Changes Surface Hydrophobicity of Candida Cells

    Directory of Open Access Journals (Sweden)

    A. F. Fonseca

    1999-01-01

    Full Text Available Hydrophobic interaction is generally considered to play an important role in the adherence of microorganisms to eukaryotic cells and also to certain inert surfaces. Using a microbe adhesion assay to hydrocarbons (n-hexadecane, 68 strains of Candida albicans and 30 non-albicans strains were studied. Influence of source of isolate, age of the culture, and percentage of germ tube formation on adhesion were studied. C: albicans blastoconidia were found to be hydrophilic; conversely, blastoconidia of non-albicans strains were slightly more hydrophobic. Germ tube formation was associated with a significant rise in cell surface hydrophobicity. Infect. Dis. Obstet. Gynecol. 7:222–226, 1999.

  17. Vaccines based on the cell surface carbohydrates of pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Jones Christopher

    2005-01-01

    Full Text Available Glycoconjugate vaccines, in which a cell surface carbohydrate from a micro-organism is covalently attached to an appropriate carrier protein are proving to be the most effective means to generate protective immune responses to prevent a wide range of diseases. The technology appears to be generic and applicable to a wide range of pathogens, as long as antibodies against surface carbohydrates help protect against infection. Three such vaccines, against Haemophilus influenzae type b, Neisseria meningitidis Group C and seven serotypes of Streptococcus pneumoniae, have already been licensed and many others are in development. This article discusses the rationale for the development and use of glycoconjugate vaccines, the mechanisms by which they elicit T cell-dependent immune responses and the implications of this for vaccine development, the role of physicochemical methods in the characterisation and quality control of these vaccines, and the novel products which are under development.

  18. Cell surface topology creates high Ca2+ signalling microdomains

    DEFF Research Database (Denmark)

    Brasen, Jens Christian; Olsen, Lars Folke; Hallett, Maurice B

    2010-01-01

    It has long been speculated that cellular microdomains are important for many cellular processes, especially those involving Ca2+ signalling. Measurements of cytosolic Ca2+ report maximum concentrations of less than few micromolar, yet several cytosolic enzymes require concentrations of more than......-wrinkle location is also a strategic location at which Ca2+ acts as a regulator of the cortical cytoskeleton and plasma membrane expansion....... smooth cell surface predicts only moderate localized effects, the more realistic "wrinkled" surface topology predicts that Ca2+ concentrations up to 80 microM can persist within the folds of membranes for significant times. This intra-wrinkle location may account for 5% of the total cell volume. Using...

  19. Quantitative characterization of pyrimidine dimer excision from UV-irradiated DNA (excision capacity) by cell-free extracts of the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Cell-free extracts from wild-type yeast (RAD+) and from rad mutants belonging to the RAD3 epistatic group (rad1-1, rad2-1, rad3-1, rad4-1) contain activities catalyzing the excision of pyrimidine dimers (PD) from purified ultraviolet-irradiated DNA which was not pre-treated with exogenous UV-endonuclease. The level of these activities in cell-free extracts from rad mutants did not differ from that in wild-type extract and was close to the in vivo excision capacity of the latter calculated from the LD37 (about 104 PD per haploid genome). (Auth.)

  20. Xylose utilizing recombinant Saccharomyces cerevisiae strains

    Energy Technology Data Exchange (ETDEWEB)

    Walfridsson, M.

    1996-04-01

    Through metabolic engineering, S. cerevisiae was provided with the necessary enzymes required for xylose utilisation during ethanolic fermentation of xylose-rich lignocellulose raw materials. For xylitol production, S. cerevisiae was provided with the Pichia stipitis XYL1 gene encoding xylose reductase (XR). The in-vivo reduction and the following excretion of xylitol, requires a co-substrate for maintenance and cofactor regeneration. Xylitol yields close to 100% were obtained with the XYL1 containing S. cerevisiae. Introducing P. stipitis XYL1 and XYL2 genes, encoding XR and xylitol dehydrogenase (XDH), respectively, enabled S. cerevisiae to convert xylose to xylulose, via xylitol. During the screening work of P. stipitis XDH gene, another gene encoding a polyol dehydrogenase was isolated and cloned in S. cerevisiae. The gene was identified as a D-arabinitol dehydrogenase gene. In P. stipitis it may function as a redox sink by reducing D-ribulose to D-arabinitol. The metabolism through the pentose phosphate pathway (PPP) was enhanced by over-expressing the native genes TKL1 and TAL1 encoding transketolase and transaldolase, respectively, resulting in improved xylose utilisation. The XR and XDH activities in recombinant S. cerevisiae were produced at different levels by constructing yeast vectors in which the PGK1 and ADHI promoters controlled XYL1 and XYL2. With higher XDH than XR activities, less by-products, in the form of xylitol and glycerol, were formed by the recombinant S. cerevisiae strains. The Thermus thermophilus xylA gene encoding a thermostable xylose isomerase was cloned and expressed in S. cerevisiae. The recombinant xylose isomerase was actively produced and a new functional metabolic pathway was established in S. cerevisiae resulting in ethanol production from xylose. 150 refs, 3 figs, 4 tabs

  1. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    International Nuclear Information System (INIS)

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N2/H2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  2. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    Science.gov (United States)

    Kaklamani, Georgia; Bowen, James; Mehrban, Nazia; Dong, Hanshan; Grover, Liam M.; Stamboulis, Artemis

    2013-05-01

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N2/H2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of Csbnd N, Cdbnd N, and Ctbnd N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  3. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kaklamani, Georgia, E-mail: g.kaklamani@bham.ac.uk [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Bowen, James; Mehrban, Nazia [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Dong, Hanshan [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom); Grover, Liam M. [University of Birmingham, College of Engineering and Physical Sciences, School of Chemical Engineering, Edgbaston, Birmingham B15 2TT (United Kingdom); Stamboulis, Artemis [University of Birmingham, College of Engineering and Physical Sciences, School of Metallurgy and Materials, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2013-05-15

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N{sub 2}/H{sub 2} ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  4. Methods To Identify Aptamers against Cell Surface Biomarkers

    OpenAIRE

    Frédéric Ducongé; Daniel Miotto Dupont; Agnes Cibiel

    2011-01-01

    Aptamers are nucleic acid-based ligands identified through a process of molecular evolution named SELEX (Systematic Evolution of Ligands by Exponential enrichment). During the last 10-15 years, numerous aptamers have been developed specifically against targets present on or associated with the surface of human cells or infectious pathogens such as viruses, bacteria, fungi or parasites. Several of the aptamers have been described as potent probes, rivalling antibodies, for use in flow cytometr...

  5. Smooth Muscle Cell Functionality on Collagen Immobilized Polycaprolactone Nanowire Surfaces

    OpenAIRE

    Victoria Leszczak; Baskett, Dominique A.; Popat, Ketul C.

    2014-01-01

    Inhibition of smooth muscle cell (SMC) proliferation and preservation of a differentiated state are important aspects in the management, avoidance and progression of vascular diseases. An understanding of the interaction between SMCs and the biomaterial involved is essential for a successful implant. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human aortic SMCs. The nanow...

  6. Biointerface: protein enhanced stem cells binding to implant surface.

    Science.gov (United States)

    Chrzanowski, W; Kondyurin, A; Lee, Jae Ho; Lord, Megan S; Bilek, M M M; Kim, Hae-Won

    2012-09-01

    The number of metallic implantable devices placed every year is estimated at 3.7 million. This number has been steadily increasing over last decades at a rate of around 8 %. In spite of the many successes of the devices the implantation of biomaterial into tissues almost universally leads to the development of an avascular sac, which consists of fibrous tissue around the device and walls off the implant from the body. This reaction can be detrimental to the function of implant, reduces its lifetime, and necessitates repeated surgery. Clearly, to reduce the number of revision surgeries and improve long-term implant function it is necessary to enhance device integration by modulating cell adhesion and function. In this paper we have demonstrated that it is possible to enhance stem cell attachment using engineered biointerfaces. To create this functional interface, samples were coated with polymer (as a precursor) and then ion implanted to create a reactive interface that aids the binding of biomolecules--fibronectin. Both AFM and XPS analyses confirmed the presence of protein layers on the samples. The amount of protein was significant greater for the ion implanted surfaces and was not disrupted upon washing with detergent, hence the formation of strong bonds with the interface was confirmed. While, for non ion implanted surfaces, a decrease of protein was observed after washing with detergent. Finally, the number of stem cells attached to the surface was enhanced for ion implanted surfaces. The studies presented confirm that the developed bionterface with immobilised fibronectin is an effective means to modulate stem cell attachment. PMID:22714559

  7. Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Irradiation effects on the alcohol fermentation ability of saccharomyces cerevisiae. S. cerevisiae suspensions of 1.5x108 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 300C 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

  8. Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model

    Directory of Open Access Journals (Sweden)

    Serge Feyder

    2015-01-01

    Full Text Available The yeast Saccharomyces cerevisiae is one of the best characterized eukaryotic models. The secretory pathway was the first trafficking pathway clearly understood mainly thanks to the work done in the laboratory of Randy Schekman in the 1980s. They have isolated yeast sec mutants unable to secrete an extracellular enzyme and these SEC genes were identified as encoding key effectors of the secretory machinery. For this work, the 2013 Nobel Prize in Physiology and Medicine has been awarded to Randy Schekman; the prize is shared with James Rothman and Thomas Südhof. Here, we present the different trafficking pathways of yeast S. cerevisiae. At the Golgi apparatus newly synthesized proteins are sorted between those transported to the plasma membrane (PM, or the external medium, via the exocytosis or secretory pathway (SEC, and those targeted to the vacuole either through endosomes (vacuolar protein sorting or VPS pathway or directly (alkaline phosphatase or ALP pathway. Plasma membrane proteins can be internalized by endocytosis (END and transported to endosomes where they are sorted between those targeted for vacuolar degradation and those redirected to the Golgi (recycling or RCY pathway. Studies in yeast S. cerevisiae allowed the identification of most of the known effectors, protein complexes, and trafficking pathways in eukaryotic cells, and most of them are conserved among eukaryotes.

  9. Can yeast (S. cerevisiae) metabolic volatiles provide polymorphic signaling?

    Science.gov (United States)

    Arguello, J Roman; Sellanes, Carolina; Lou, Yann Ru; Raguso, Robert A

    2013-01-01

    Chemical signaling between organisms is a ubiquitous and evolutionarily dynamic process that helps to ensure mate recognition, location of nutrients, avoidance of toxins, and social cooperation. Evolutionary changes in chemical communication systems progress through natural variation within the organism generating the signal as well as the responding individuals. A promising yet poorly understood system with which to probe the importance of this variation exists between D. melanogaster and S. cerevisiae. D. melanogaster relies on yeast for nutrients, while also serving as a vector for yeast cell dispersal. Both are outstanding genetic and genomic models, with Drosophila also serving as a preeminent model for sensory neurobiology. To help develop these two genetic models as an ecological model, we have tested if - and to what extent - S. cerevisiae is capable of producing polymorphic signaling through variation in metabolic volatiles. We have carried out a chemical phenotyping experiment for 14 diverse accessions within a common garden random block design. Leveraging genomic sequences for 11 of the accessions, we ensured a genetically broad sample and tested for phylogenetic signal arising from phenotypic dataset. Our results demonstrate that significant quantitative differences for volatile blends do exist among S. cerevisiae accessions. Of particular ecological relevance, the compounds driving the blend differences (acetoin, 2-phenyl ethanol and 3-methyl-1-butanol) are known ligands for D. melanogasters chemosensory receptors, and are related to sensory behaviors. Though unable to correlate the genetic and volatile measurements, our data point clear ways forward for behavioral assays aimed at understanding the implications of this variation. PMID:23990899

  10. Overproduction of fission yeast eif3a subunit in saccharomyces cerevisiae results in aberrant cell morphology and g2/m delay

    Czech Academy of Sciences Publication Activity Database

    Janatová, Ivana; Koubek, Zdeněk; Malínská, Kateřina; Raková, Radka; Hašek, Jiří

    Cold Spring Harbor, New York, 2003, s. 23. [Meeting on Yeast Cell Biology /2003./. Cold Spring Harbor (US), 12.08.2003-17.08.2003] R&D Projects: GA ČR GA204/02/1424 Institutional research plan: CEZ:AV0Z5020903 Keywords : facs * rpg1p Subject RIV: EE - Microbiology, Virology

  11. Biosorption of Americium-242 by saccharomyces cerevisiae: preliminary evaluation and mechanism

    International Nuclear Information System (INIS)

    As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of 241Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total 241Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from 241Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus, but the some components of S. cerevisiae, such as protein and acylation group had obvious effect on adsorption. When the concentrations of coexistent Eu3+, Nd3+ were 100 times more than that of 241Am, the adsorption rates would drop to 65%. However, most of the investigated acidic ions have no significant influence on the 241Am adsorption but minute change of pH value, while the saturated EDTA can strong inhibit the biosorption of 241Am.. (authors)

  12. Structure of a Bacterial Cell Surface Decaheme Electron Conduit

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Thomas A.; Edwards, Marcus; Gates, Andrew J.; Hall, Andrea; White, Gaye; Bradley, Justin; Reardon, Catherine L.; Shi, Liang; Beliaev, Alex S.; Marshall, Matthew J.; Wang, Zheming; Watmough, Nicholas; Fredrickson, Jim K.; Zachara, John M.; Butt, Julea N.; Richardson, David J.

    2011-05-23

    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves deca-heme cytochromes that are located on the bacterial cell surface at the termini of trans-outermembrane (OM) electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or participating in extracellular inter-cytochrome electron exchange along ‘nanowire’ appendages. We present a 3.2 Å crystal structure of one of these deca-heme cytochromes, MtrF, that allows the spatial organization of the ten hemes to be visualized for the first time. The hemes are organized across four domains in a unique crossed conformation, in which a staggered 65 Å octa-heme chain transects the length of the protein and is bisected by a planar 45 Å tetra-heme chain that connects two extended Greek key split β-barrel domains. The structure provides molecular insight into how reduction of insoluble substrate (e.g. minerals), soluble substrates (e.g. flavins) and cytochrome redox partners might be possible in tandem at different termini of a trifurcated electron transport chain on the cell surface.

  13. Surface recombination analysis in silicon-heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, R.; Gandia, J.J.; Carabe, J.; Gonzalez, N.; Torres, I. [CIEMAT, Madrid (Spain); Munoz, D.; Voz, C. [Universitat Politecnica de Catalunya, Barcelona (Spain)

    2010-02-15

    The origin of this work is the understanding of the correlation observed between efficiency and emitter-deposition temperature in single silicon-heterojunction solar cells prepared by depositing an n-doped hydrogenated-amorphous-silicon thin film onto a p-type crystalline-silicon wafer. In order to interpret these results, surface-recombination velocities have been determined by two methods, i.e. by fitting the current-voltage characteristics to a theoretical model and by means of the Quasi-Steady-State Photoconductance Technique (QSSPC). In addition, effective diffusion lengths have been estimated from internal quantum efficiencies. The analysis of these data has led to conclude that the performance of the cells studied is limited by back-surface recombination rather than by front-heterojunction quality. A 12%-efficient cell has been prepared by combining optimum emitter-deposition conditions with back-surface-field (BSF) formation by vacuum annealing of the back aluminium contact. This result has been achieved without using any transparent conductive oxide. (author)

  14. Hydrophobic and electrostatic cell surface properties of thermophilic dairy streptococci.

    Science.gov (United States)

    van der Mei, H C; de Vries, J; Busscher, H J

    1993-12-01

    Microbial adhesion to hydrocarbons (MATH) and microelectrophoresis were done in 10 mM potassium phosphate solutions to characterize the surfaces of thermophilic dairy streptococci, isolated from pasteurizers. Regardless of whether they were grown (in M17 broth) with lactose, sucrose, or glucose added, strains were relatively hydrophilic (showing low initial removal rates by hexadecane) and slightly negatively charged. A tendency exists for cells grown with sucrose added to be more hydrophilic than cells grown with glucose or lactose added. Also, the lowest isoelectric points, i.e., the pH values for which the zeta potentials are zero, were measured for strains with glucose added to the growth medium. The isoelectric points for the strains were all rather high, between pH 3 and 5, indicative of protein-rich surfaces, although X-ray photoelectron spectroscopy did not measure excessively large amounts of nitrogen on the cell surfaces. Both MATH and microelectrophoresis were done as a function of pH. Maxima in hydrophobicity were observed at certain pH values. Usually these pH values were in the range of the isoelectric points of the cells. Thus it appears that MATH measures an interplay of hydrophobicity and electrostatic interactions. MATH measures solely hydrophobicity only when electrostatic interactions are absent, i.e., close to the isoelectric points of the cells. Considering that these thermophilic streptococci are all rather hydrophilic, a possible pathway to prevent fouling in the pasteurization process might be to render the heat exchanger plates of the pasteurizer more hydrophobic. PMID:16349127

  15. Parameter Optimization for Enhancement of Ethanol Yield by Atmospheric Pressure DBD-Treated Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    In this study, Saccharomyces cerevisiae (S. cerevisiae) was exposed to dielectric barrier discharge plasma (DBD) to improve its ethanol production capacity during fermentation. Response surface methodology (RSM) was used to optimize the discharge-associated parameters of DBD for the purpose of maximizing the ethanol yield achieved by DBD-treated S. cerevisiae. According to single factor experiments, a mathematical model was established using Box-Behnken central composite experiment design, with plasma exposure time, power supply voltage, and exposed-sample volume as impact factors and ethanol yield as the response. This was followed by response surface analysis. Optimal experimental parameters for plasma discharge-induced enhancement in ethanol yield were plasma exposure time of 1 min, power voltage of 26 V, and an exposed sample volume of 9 mL. Under these conditions, the resulting yield of ethanol was 0.48 g/g, representing an increase of 33% over control. (plasma technology)

  16. Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals

    DEFF Research Database (Denmark)

    Borodina, Irina; Nielsen, Jens

    2014-01-01

    Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the...... development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology...

  17. 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.

  18. Cell-surface expression of Hsp70 on hematopoietic cancer cells after inhibition of HDAC activity

    DEFF Research Database (Denmark)

    Jensen, Helle

    frequently express Hsp70 on their cell surface, whereas the corresponding normal tissues do not. In addition, several clinically applied reagents, such as alkyl-lysophospholipides, chemotherapeutic agents, and anti-inflammatory reagents, have been found to enhance Hsp70 cell surface expression on cancer...... cells. We have found that inhibition of histone deacetylase (HDAC) activity leads to surface expression of Hsp70 on various hematopoietic cancer cells, an occurance that was not observed on naïve or activated peripheral blood cells. HDAC-inhibitor mediated Hsp70 cell surface expression was confined to...... transport and cell surface binding of Hsp70 after HDAC-inhibitor treatment remains elusive. Our data suggest that inhibition of HDAC activity selectively induces cell surface expression of Hsp70 on hematopoietic cancer cells, and this may increase the immunorecognition of these cells. It could be envisaged...

  19. Cell surface carbohydrates as prognostic markers in human carcinomas

    DEFF Research Database (Denmark)

    Dabelsteen, Erik

    1996-01-01

    cell types; within a given tissue, variation in expression may be related to cell maturation. Tumour-associated carbohydrate structures often reflect a certain stage of cellular development; most of these moieties are structures normally found in other adult or embryonic tissues. There is no unique......Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core...... tumour carbohydrate structure, since certain structures which are tumour-related in one organ may be normal constituents of other tissues. Tumour-associated carbohydrate changes have been used in the diagnosis of human cancers. Recently, however, it has been demonstrated that the expression of some...

  20. Surface deformation and shear flow in ligand mediated cell adhesion

    Science.gov (United States)

    Sircar, Sarthok; Roberts, Anthony; Sarthok Sircar / Anthony Roberts Collaboration

    We present a unified, multiscale model to study the attachment/detachment dynamics of two deforming, near spherical cells, coated with binding ligands and subject to a slow, homogeneous shear flow in a viscous fluid medium. The binding ligands on the surface of the cells experience attractive and repulsive forces in an ionic medium and exhibit finite resistance to rotation via bond tilting. The microscale drag forces and couples describing the fluid flow inside the small separation gap between the cells, are calculated using a combination of methods in lubrication theory and previously published numerical results. For a select range of material and fluid parameters, a hysteretic transition of the sticking probability curves (i.e., the function g*) between the adhesion phase (when g*>0.5) and the fragmentation phase (when g*University startup funds and AR is supported by the Australian Research Council Discovery Grant DP150102385.

  1. Development of living cell force sensors for the interrogation of cell surface interactions

    Science.gov (United States)

    Brown, Scott Chang

    The measurement of cell surface interactions, or cell interaction forces, are critical for the early diagnosis and prevention of disease, the design of targeted drug and gene delivery vehicles, the development of next-generation implant materials, and much more. However, the technologies and devices that are currently available are highly limited with respect to the dynamic force range over which they can measure cell-cell or cell-substratum interactions, and with their ability to adequately mimic biologically relevant systems. Consequently, research efforts that involve cell surface interactions have been limited. In this dissertation, existing tools for research at the nanoscale (i.e., atomic force microscopy microcantilevers) are modified to develop living cell force sensors that allow for the highly sensitive measurement of cell-mediated interactions over the entire range of forces expected in biotechnology (and nano-biotechnology) research (from a single to millions of receptor-ligand bonds). Several force sensor motifs have been developed that can be used to measure interactions using single adherent cells, single suspension culture cell, and cell monolayers (tissues) over a wide range of interaction conditions (e.g., approach velocity, shear rate, contact time) using a conventional atomic force microscope. This new tool has been applied to study the pathogenesis of spontaneous pneumothorax and the interaction of cells with 14 man-made interfaces. Consequently, a new hypothesis of the interactions that manifest spontaneous pneumothorax has been developed. Additionally, these findings have the potential to lead to the development of tools for data mining materials and surfaces for unique cell interactions that could have an immense societal impact.

  2. Short-chain ceramides depress integrin cell surface expression and function in colorectal cancer cells.

    Science.gov (United States)

    Morad, Samy A F; Bridges, Lance C; Almeida Larrea, Alex D; Mayen, Anthony L; MacDougall, Matthew R; Davis, Traci S; Kester, Mark; Cabot, Myles C

    2016-07-01

    Colorectal cancer (CRC) is highly metastatic, significantly so to liver, a characteristic that embodies one of the most challenging aspects of treatment. The integrin family of cell-cell and cell-matrix adhesion receptors plays a central role in migration and invasion, functions that underlie metastatic potential. In the present work we sought to determine the impact of ceramide, which plays a key modulatory role in cancer suppression, on integrin cell surface expression and function in CRC cells in order to reveal possible ceramide-centric effects on tumor cell motility. Human CRC cells LoVo, HT-29, and HCT-116 were employed, which represent lines established from primary and metastatic sites. A cell-permeable, short-chain analog, C6-ceramide, was used as ceramide mimic. Exposure of cells to C6-ceramide (24 h) promoted a dose-dependent (2.5-10 µM) decrease in the expression of cell surface β1 and β4 integrin subunits in all cell lines; at 10 µM C6-ceramide, the decreases ranged from 30 to 50% of the control. Expression of cell surface αVβ6 integrin, which is associated with advanced invasion in CRC, was also suppressed by C6-ceramide. Decreases in integrin expression translated to diminished cellular adhesion, 50% of the control at 5 µM C6-ceramide, and markedly reduced cellular migration, approximately 30-40% of the control in all cell lines. Physicochemical examination revealed potent efficacy of nano-formulated C6-ceramide, but inferior activity of dihydro-C6-ceramide and L-C6-ceramide, compared to the unsaturated counterpart and the natural d-enantiomer, respectively. These studies demonstrate novel actions of ceramides that may have application in suppression of tumor metastasis, in addition to their known tumor suppressor effects. PMID:27045476

  3. Antimicrobial peptides (AMPs) produced by Saccharomyces cerevisiae induce alterations in the intracellular pH, membrane permeability and culturability of Hanseniaspora guilliermondii cells

    DEFF Research Database (Denmark)

    Branco, Patrícia; Monteiro Lomba Viana, Tiago; Albergaria, Helena;

    2015-01-01

    Saccharomyces cerevisiae produces antimicrobial peptides (AMPs) during alcoholic fermentation that are active against several wine-related yeasts (e.g. Hanseniaspora guilliermondii) and bacteria (e.g. Oenococcus oeni). In the present study, the physiological changes induced by those AMPs on...

  4. Saccharomyces cerevisiae EC-1118 enhances the survivability of probiotic Lactobacillus rhamnosus HN001 in an acidic environment.

    Science.gov (United States)

    Lim, Phebe Lixuan; Toh, Mingzhan; Liu, Shao Quan

    2015-08-01

    The present study attempted to partially characterize and elucidate the viability-enhancing effect of a yeast strain Saccharomyces cerevisiae EC-1118 on a probiotic strain Lactobacillus rhamnosus HN001 under acidic conditions using a model system (non-growing cells). The yeast was found to significantly enhance (P < 0.05) the viability of the probiotic strain under acidic conditions (pH 2.5 to 4.0) by 2 to 4 log cycles, and the viability-enhancing effects were observed to be influenced by pH, and probiotic and yeast concentrations. Microscopic observation and co-aggregation assay revealed that the viability-enhancing effect of the yeast could be attributed to direct cell-cell contact co-aggregation mediated by yeast cell surface and/or cell wall components or metabolites. Furthermore, non-viable yeast cells killed by thermal means were observed to enhance the viability of the probiotic strain as well, suggesting that the surface and/or cell wall component(s) of the yeast contributing to co-aggregation was heat-stable. Cell-free yeast supernatant was also found to enhance the viability of the probiotic strain, indicating the presence of protective yeast metabolite(s) in the supernatant. These findings laid the foundation for further understanding of the mechanism(s) involved and for developing novel microbial starter cultures possibly without the use of live yeast for ambient-stable high-moisture probiotic foods. PMID:25846337

  5. Analysis of the biological effects of a non-thermal plasma on saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyung S.; Baik, Ku Y.; Kim, Jung G.; Kim, Yun J.; Lee, Kyung A.; Jung, Ran J.; Cho, Guang S. [Kwangwoon University, Seoul (Korea, Republic of)

    2012-03-15

    The cellular and the molecular responses of eukaryotic yeast (Saccharomyces cerevisiae) to a non-thermal plasma at atmospheric pressure are analyzed. A plasma device with a dielectric barrier discharge is used in order to understand the mechanisms of the plasma action on eukaryotic microbes. When the yeast cells are exposed to a plasma (at a 2-mm distance) and then cultured on a YPD (yeast extract, peptone, and dextrose) - agar plate, the number of surviving cells is reduced over exposure time. More than a 50% reduction in number is observed after two exposures of 5 minutes' duration. In addition, very small whitish colonies appear after the two exposures. The microscopic analysis indicates that the yeast cells treated with this plasma exposure have rough and shrunken shapes in comparison to the oval shapes with smooth surfaces of the control cells. The profile of proteins analyzed by using 2-dimentional electrophoresis demonstrates that the level of proteins with high molecular weights is increased in plasma-treated cells.

  6. Methionine catabolism in Saccharomyces cerevisiae.

    Science.gov (United States)

    Perpète, Philippe; Duthoit, Olivier; De Maeyer, Simon; Imray, Louise; Lawton, Andrew I; Stavropoulos, Konstantinos E; Gitonga, Virginia W; Hewlins, Michael J E; Dickinson, J Richard

    2006-01-01

    The catabolism of methionine to methionol and methanethiol in Saccharomyces cerevisiae was studied using (13)C NMR spectroscopy, GC-MS, enzyme assays and a number of mutants. Methionine is first transaminated to alpha-keto-gamma-(methylthio)butyrate. Methionol is formed by a decarboxylation reaction, which yields methional, followed by reduction. The decarboxylation is effected specifically by Ydr380wp. Methanethiol is formed from both methionine and alpha-keto-gamma-(methylthio)butyrate by a demethiolase activity. In all except one strain examined, demethiolase was induced by the presence of methionine in the growth medium. This pathway results in the production of alpha-ketobutyrate, a carbon skeleton, which can be re-utilized. Hence, methionine catabolism is more complex and economical than the other amino acid catabolic pathways in yeast, which use the Ehrlich pathway and result solely in the formation of a fusel alcohol. PMID:16423070

  7. RPE cell surface proteins in normal and dystrophic rats

    International Nuclear Information System (INIS)

    Membrane-bound proteins in plasma membrane enriched fractions from cultured rat RPE were analyzed by two-dimensional gel electrophoresis. Membrane proteins were characterized on three increasingly specific levels. Total protein was visualized by silver staining. A maximum of 102 separate proteins were counted in silver-stained gels. Glycoproteins were labeled with 3H-glucosamine or 3H-fucose and detected by autoradiography. Thirty-eight fucose-labeled and 61-71 glucosamine-labeled proteins were identified. All of the fucose-labeled proteins were labeled with glucosamine-derived radioactivity. Proteins exposed at the cell surface were labeled by lactoperoxidase-catalyzed radioiodination prior to preparation of membranes for two-dimensional analysis. Forty separate 125I-labeled surface proteins were resolved by two-dimensional electrophoresis/autoradiography. Comparison with the glycoprotein map showed that a number of these surface labeled proteins were glycoproteins. Two-dimensional maps of total protein, fucose-labeled, and glucosamine-labeled glycoproteins, and 125I-labeled surface proteins of membranes from dystrophic (RCS rdy-p+) and normal (Long Evans or RCS rdy+p+) RPE were compared. No differences in the total protein or surface-labeled proteins were observed. However, the results suggest that a 183K glycoprotein is more heavily glycosylated with glucosamine and fucose in normal RPE membranes as compared to membranes from dystrophic RPE

  8. Electrical stimulation of saccharomyces cerevisiae cultures Estimulação elétrica de células de Saccharomyces cerevisiae

    OpenAIRE

    Ofelia Q.F. Araújo; Coelho, Maria Alice Z.; Isabel C.P. Margarit; Carlos A. Vaz-Junior; Maria Helena M. Rocha-Leão

    2004-01-01

    Modulation of cell endogenous membrane potential by an external electrical field influences the structure and function of membrane compartments, proteins and lipid bi-layer. In this work, the effects of applied potential on Saccharomyces cerevisiae growth were characterized through simple yet conclusive experiments. Cell growth time profile and cell division were investigated as macroscopic response to the electrical stimulation. Control experiments were conducted under identical conditions e...

  9. Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes: role of physiological fitness and microbial interactions.

    Science.gov (United States)

    Albergaria, Helena; Arneborg, Nils

    2016-03-01

    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 contribute to the sensory properties of end-products, the yeast S. cerevisiae invariably dominates the final stages of fermentation. The ability of S. cerevisiae to outcompete other microbial species during alcoholic fermentation processes, such as winemaking, has traditionally been ascribed to its high fermentative power and capacity to withstand the harsh environmental conditions, i.e. high levels of ethanol and organic acids, low pH values, scarce oxygen availability and depletion of certain nutrients. However, in recent years, several studies have raised evidence that S. cerevisiae, beyond its remarkable fitness for alcoholic fermentation, also uses defensive strategies mediated by different mechanisms, such as cell-to-cell contact and secretion of antimicrobial peptides, to combat other microorganisms. In this paper, we review the main physiological features underlying the special aptitude of S. cerevisiae for alcoholic fermentation and discuss the role of microbial interactions in its dominance during alcoholic fermentation, as well as its relevance for winemaking. PMID:26728020

  10. Interaction of KSHV with Host Cell Surface Receptors and Cell Entry

    Directory of Open Access Journals (Sweden)

    Mohanan Valiya Veettil

    2014-10-01

    Full Text Available Virus entry is a complex process characterized by a sequence of events. Since the discovery of KSHV in 1994, tremendous progress has been made in our understanding of KSHV entry into its in vitro target cells. KSHV entry is a complex multistep process involving viral envelope glycoproteins and several cell surface molecules that is utilized by KSHV for its attachment and entry. KSHV has a broad cell tropism and the attachment and receptor engagement on target cells have an important role in determining the cell type-specific mode of entry. KSHV utilizes heparan sulfate, integrins and EphrinA2 molecules as receptors which results in the activation of host cell pre-existing signal pathways that facilitate the subsequent cascade of events resulting in the rapid entry of virus particles, trafficking towards the nucleus followed by viral and host gene expression. KSHV enters human fibroblast cells by dynamin dependant clathrin mediated endocytosis and by dynamin independent macropinocytosis in dermal endothelial cells. Once internalized into endosomes, fusion of the viral envelope with the endosomal membranes in an acidification dependent manner results in the release of capsids which subsequently reaches the nuclear pore vicinity leading to the delivery of viral DNA into the nucleus. In this review, we discuss the principal mechanisms that enable KSHV to interact with the host cell surface receptors as well as the mechanisms that are required to modulate cell signaling machinery for a successful entry.

  11. Acetylation dynamics and stoichiometry in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Weinert, Brian Tate; Iesmantavicius, Vytautas; Moustafa, Tarek; Schölz, Christian; Wagner, Sebastian A; Magnes, Christoph; Zechner, Rudolf; Choudhary, Chuna Ram

    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...

  12. Effects of initial pH value of the medium on the alcoholic fermentation performance of Saccharomyces cerevisiae cells immobilized on nipa leaf sheath pieces

    OpenAIRE

    Hoang Duc Toan Le; Van Viet Man Le

    2014-01-01

    Immobilized yeast on nipa leaf sheath pieces was applied to ethanol fermentation using the medium with different initial pH values (5.1, 4.5, 4.0, and 3.5). Control samples with the free yeast were also carried out under the same conditions. Low pH value of 4.0 or 3.5 significantly reduced yeast growth and increased the residual sugar level in the fermentation broths for both the immobilized and free cells. In all cases, the ethanol content produced and ethanol formation rate of the ...

  13. Live cell imaging of the assembly, disassembly, and actin cable–dependent movement of endosomes and actin patches in the budding yeast, Saccharomyces cerevisiae

    OpenAIRE

    Huckaba, Thomas M.; Gay, Anna Card; Pantalena, Luiz Fernando; Yang, Hyeong-Cheol; Liza A Pon

    2004-01-01

    Using FM4-64 to label endosomes and Abp1p-GFP or Sac6p-GFP to label actin patches, we find that (1) endosomes colocalize with actin patches as they assemble at the bud cortex; (2) endosomes colocalize with actin patches as they undergo linear, retrograde movement from buds toward mother cells; and (3) actin patches interact with and disassemble at FM4-64–labeled internal compartments. We also show that retrograde flow of actin cables mediates retrograde actin patch movement. An Arp2/3 complex...

  14. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production

    Science.gov (United States)

    Liu, Zhuo; Ho, Shih-Hsin; Sasaki, Kengo; den Haan, Riaan; Inokuma, Kentaro; Ogino, Chiaki; van Zyl, Willem H.; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell surface. The cellulase-displaying yeast strain exhibited clear cell-to-cellulose adhesion and a “tearing” cellulose degradation pattern; the adhesion ability correlated with enhanced surface area and roughness of the target cellulose fibers, resulting in higher hydrolysis efficiency. The engineered yeast directly produced ethanol from rice straw despite a more than 40% decrease in the required enzyme dosage for high-density fermentation. Thus, improved cell-to-cellulose interactions provided a novel strategy for increasing cellulose hydrolysis, suggesting a mechanism for promoting the feasibility of cellulosic biofuel production. PMID:27079382

  15. Mediated electrochemical measurement of the inhibitory effects of furfural and acetic acid on Saccharomyces cerevisiae and Candida shehatae.

    Science.gov (United States)

    Zhao, Jinsheng; Wang, Min; Yang, Zhenyu; Gong, Qintao; Lu, Yao; Yang, Zhengyu

    2005-02-01

    The toxic effects of furfural and acetic acid on two yeasts, Saccharomyces cerevisiae and Candida shehatae, were evaluated using an electrochemical method. Intracellular redox activities were lowered by 40% and 78% for S. cerevisiae and C. shehatae, respectively, by 8 g furfural l(-1), and by 46% and 67%, respectively, by 8 g acetic acid l(-1). The proposed method can accurately measure the effects of inhibitors on cell cultures. PMID:15717131

  16. EasyClone 2.0:expanded toolkit of integrative vectors for stable gene expression in industrial Saccharomyces cerevisiae strains

    OpenAIRE

    Stovicek, Vratislav; Borja Zamfir, Gheorghe Manuel; Förster, Jochen; Borodina, Irina

    2015-01-01

    Saccharomyces cerevisiae is one of the key cell factories for production of chemicals and active pharmaceuticals. For large-scale fermentations, particularly in biorefinery applications, it is desirable to use stress-tolerant industrial strains. However, such strains are less amenable for metabolic engineering than the standard laboratory strains. To enable easy delivery and overexpression of genes in a wide range of industrial S. cerevisiae strains, we constructed a set of integrative vector...

  17. Cancer cell uptake behavior of Au nanoring and its localized surface plasmon resonance induced cell inactivation

    International Nuclear Information System (INIS)

    Au nanorings (NRIs), which have the localized surface plasmon resonance (LSPR) wavelength around 1058 nm, either with or without linked antibodies, are applied to SAS oral cancer cells for cell inactivation through the LSPR-induced photothermal effect when they are illuminated by a laser of 1065 nm in wavelength. Different incubation times of cells with Au NRIs are considered for observing the variations of cell uptake efficiency of Au NRI and the threshold laser intensity for cell inactivation. In each case of incubation time, the cell sample is washed for evaluating the total Au NRI number per cell adsorbed and internalized by the cells based on inductively coupled plasma mass spectrometry measurement. Also, the Au NRIs remaining on cell membrane are etched with KI/I2 solution to evaluate the internalized Au NRI number per cell. The threshold laser intensities for cell inactivation before washout, after washout, and after KI/I2 etching are calibrated from the circular area sizes of inactivated cells around the illuminated laser spot center with various laser power levels. By using Au NRIs with antibodies, the internalized Au NRI number per cell increases monotonically with incubation time up to 24 h. However, the number of Au NRI remaining on cell membrane reaches a maximum at 12 h in incubation time. The cell uptake behavior of an Au NRI without antibodies is similar to that with antibodies except that the uptake NRI number is significantly smaller and the incubation time for the maximum NRI number remaining on cell membrane is delayed to 20 h. By comparing the threshold laser intensities before and after KI/I2 etching, it is found that the Au NRIs remaining on cell membrane cause more effective cancer cell inactivation, when compared with the internalized Au NRIs. (paper)

  18. Heat shock, visible light or high calcium augment the cytotoxic effects of Ailanthus altissima (Swingle) leaf extracts against Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Popa, Claudia Valentina; Lungu, Liliana; Cristache, Ligia Florentina; Ciuculescu, Crinu; Danet, Andrei Florin; Farcasanu, Ileana Cornelia

    2015-01-01

    To gain new insight into the antimicrobial potential of Ailanthus altissima Swingle, ethanol leaf extracts were evaluated for the antifungal effects against the model yeast Saccharomyces cerevisae. The extracts inhibited the yeast growth in a dose-dependent manner, and this effect could be augmented by heat shock, exposure to visible light or exposure to high concentrations of Ca(2+). Using transgenic yeast cells expressing the Ca(2+)-dependent photoprotein, aequorin, it was found that the leaf extracts induced cytosolic Ca(2+) elevation. Experiments on yeast mutants with defects in Ca(2+) transport demonstrated that the cytotoxicity of the A. altissima leaf extracts (AaLEs) was mediated by transient pulses of Ca(2+) ions which were released into the cytosol predominantly from the vacuole. The investigation of the antifungal synergies involving AaLEs may contribute to the development of optimal and safe combination therapies for the treatment of drug-resistant fungal infections. PMID:25587627

  19. Cell surface glycopeptides from human intestinal epithelial cell lines derived from normal colon and colon adenocarcinomas

    International Nuclear Information System (INIS)

    The cell surface glycopeptides from an epithelial cell line (CCL 239) derived from normal human colon were compared with those from three cell lines (HCT-8R, HCT-15, and CaCo-2) derived independently from human colonic adenocarcinomas. Cells were incubated with D-[2-3H]mannose or L-[5,6-3H]fucose for 24 h and treated with trypsin to release cell surface components which were then digested exhaustively with Pronase and fractionated on Bio-Gel P-6 before and after treatment with endo-beta-N-acetylglucosaminidase H. The most noticeable difference between the labeled glycopeptides from the tumor and CCL 239 cells was the presence in the former of an endo-beta-N-acetylglucosaminidase H-resistant high molecular weight glycopeptide fraction which was eluted in the void volume of Bio-Gel P-6. This fraction was obtained with both labeled mannose and fucose as precursors. However, acid hydrolysis of this fraction obtained after incubation with [2-3H]mannose revealed that as much as 60-90% of the radioactivity was recovered as fucose. Analysis of the total glycopeptides (cell surface and cell pellet) obtained after incubation with [2-3H]mannose showed that from 40-45% of the radioactivity in the tumor cells and less than 10% of the radioactivity in the CCL 239 cells was recovered as fucose. After incubation of the HCT-8R cells with D-[1,6-3H]glucosamine and L-[1-14C]fucose, strong acid hydrolysis of the labeled glycopeptide fraction excluded from Bio-Gel P-6 produced 3H-labeled N-acetylglucosamine and N-acetylgalactosamine

  20. Cell Surface Interference with Plasma Membrane and Transport Processes in Yeasts.

    Science.gov (United States)

    Francois, Jean Marie

    2016-01-01

    The wall of the yeast Saccharomyces cerevisiae is a shell of about 120 nm thick, made of two distinct layers, which surrounds the cell. The outer layer is constituted of highly glycosylated proteins and the inner layer is composed of β-glucan and chitin. These two layers are interconnected through covalent linkages leading to a supramolecular architecture that is characterized by physical and chemical properties including rigidity, porosity and biosorption. The later property results from the presence of highly negative charged phosphate and carboxylic groups of the cell wall proteins, allowing the cell wall to act as an efficient barrier to metals ions, toxins and organic compounds. An intimate connection between cell wall and plasma membrane is indicated by the fact that changes in membrane fluidity results in change in cell wall nanomechanical properties. Finally, cell wall contributes to transport processes through the use of dedicated cell wall mannoproteins, as it is the case for Fit proteins implicated in the siderophore-iron bound transport and the Tir/Dan proteins family in the uptake of sterols. PMID:26721269

  1. Evaluation of Relative Yeast Cell Surface Hydrophobicity Measured by Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Lisa Colling

    2005-01-01

    Full Text Available Objective: To develop an efficient method for evaluating cell surface hydrophobicity and to apply the method to demonstrate the effects of fungal growth conditions on cell surface properties.

  2. Identification of astrocytoma associated genes including cell surface markers

    International Nuclear Information System (INIS)

    Despite intense effort the treatment options for the invasive astrocytic tumors are still limited to surgery and radiation therapy, with chemotherapy showing little or no increase in survival. The generation of Serial Analysis of Gene Expression (SAGE) profiles is expected to aid in the identification of astrocytoma-associated genes and highly expressed cell surface genes as molecular therapeutic targets. SAGE tag counts can be easily added to public expression databases and quickly disseminated to research efforts worldwide. We generated and analyzed the SAGE transcription profiles of 25 primary grade II, III and IV astrocytomas [1]. These profiles were produced as part of the Cancer Genome Anatomy Project's SAGE Genie [2], and were used in an in silico search for candidate therapeutic targets by comparing astrocytoma to normal brain transcription. Real-time PCR and immunohistochemistry were used for the validation of selected candidate target genes in 2 independent sets of primary tumors. A restricted set of tumor-associated genes was identified for each grade that included genes not previously associated with astrocytomas (e.g. VCAM1, SMOC1, and thymidylate synthetase), with a high percentage of cell surface genes. Two genes with available antibodies, Aquaporin 1 and Topoisomerase 2A, showed protein expression consistent with transcript level predictions. This survey of transcription in malignant and normal brain tissues reveals a small subset of human genes that are activated in malignant astrocytomas. In addition to providing insights into pathway biology, we have revealed and quantified expression for a significant portion of cell surface and extra-cellular astrocytoma genes

  3. Identification of astrocytoma associated genes including cell surface markers

    Directory of Open Access Journals (Sweden)

    Eberhart Charles G

    2004-07-01

    Full Text Available Abstract Background Despite intense effort the treatment options for the invasive astrocytic tumors are still limited to surgery and radiation therapy, with chemotherapy showing little or no increase in survival. The generation of Serial Analysis of Gene Expression (SAGE profiles is expected to aid in the identification of astrocytoma-associated genes and highly expressed cell surface genes as molecular therapeutic targets. SAGE tag counts can be easily added to public expression databases and quickly disseminated to research efforts worldwide. Methods We generated and analyzed the SAGE transcription profiles of 25 primary grade II, III and IV astrocytomas 1. These profiles were produced as part of the Cancer Genome Anatomy Project's SAGE Genie 2, and were used in an in silico search for candidate therapeutic targets by comparing astrocytoma to normal brain transcription. Real-time PCR and immunohistochemistry were used for the validation of selected candidate target genes in 2 independent sets of primary tumors. Results A restricted set of tumor-associated genes was identified for each grade that included genes not previously associated with astrocytomas (e.g. VCAM1, SMOC1, and thymidylate synthetase, with a high percentage of cell surface genes. Two genes with available antibodies, Aquaporin 1 and Topoisomerase 2A, showed protein expression consistent with transcript level predictions. Conclusions This survey of transcription in malignant and normal brain tissues reveals a small subset of human genes that are activated in malignant astrocytomas. In addition to providing insights into pathway biology, we have revealed and quantified expression for a significant portion of cell surface and extra-cellular astrocytoma genes.

  4. Silicon solar cells with polysilicon emitters and back surface fields

    Science.gov (United States)

    Du, Jiang; Berndt, Lyall P.; Tarr, N. Garry

    2010-06-01

    The first solar cells using in-situ doped polysilicon contacts to form both emitter and back surface field (BSF) regions are reported. The use of polysilicon contacts permits extremely low thermal budget processing (maximum 850°C 5 sec for dopant activation), preserving substrate properties. The effectiveness of the BSF is best seen with backside illumination, where the photocurrent under natural sunlight is found to be over 30% of that obtained with frontside illumination, even though the substrate thickness is comparable to the minority carrier diffusion length. The applicability of the structure to bifacial operation is considered.

  5. Effects of initial pH value of the medium on the alcoholic fermentation performance of Saccharomyces cerevisiae cells immobilized on nipa leaf sheath pieces

    Directory of Open Access Journals (Sweden)

    Hoang Duc Toan Le

    2014-12-01

    Full Text Available Immobilized yeast on nipa leaf sheath pieces was applied to ethanol fermentation using the medium with different initial pH values (5.1, 4.5, 4.0, and 3.5. Control samples with the free yeast were also carried out under the same conditions. Low pH value of 4.0 or 3.5 significantly reduced yeast growth and increased the residual sugar level in the fermentation broths for both the immobilized and free cells. In all cases, the ethanol content produced and ethanol formation rate of the immobilized yeast were 13-33% and 35-69%, respectively, higher than those of the free yeast. In addition, the residual sugar content in the immobilized yeast cultures was 2.1-20.5 times lower than that in the free yeast cultures. The yeast immobilized on nipa leaf stem pieces exhibited higher alcoholic fermentation performance than the free yeast in medium with low pH value. This support was potential for further research for application in ethanol industry.

  6. Near-surface alloys for hydrogen fuel cell applications

    DEFF Research Database (Denmark)

    Greeley, Jeffrey Philip; Mavrikakis, Manos

    2006-01-01

    facile H-2 activation. These NSAs could, potentially, facilitate highly selective hydrogenation reactions at low temperatures. In the present work, the suitability of NSAs for use as hydrogen fuel cell anodes has been evaluated: the combination of properties, possessed by selected NSAs, of weak binding......Near-surface alloys (NSAs) possess a variety of unusual catalytic properties that could make them useful candidates for improved catalysts in a variety of chemical processes. It is known from previous work, for example, that some NSAs bind hydrogen very weakly while, at the same time, permitting...... variety of such materials for use in fuel cells and in an ever. increasing range of catalytic applications. Furthermore, we introduce a new concept for NSA-defect sites, which could be responsible for the promotional catalytic effects of a second metal added. even in minute quantities, to a host metal...

  7. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions

    OpenAIRE

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M.; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C.; Alexander, Morgan R.; Langer, Robert; Anderson, Daniel G.; Jaenisch, Rudolf

    2011-01-01

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell...

  8. A role for Mfb1p in region-specific anchorage of high-functioning mitochondria and lifespan in Saccharomyces cerevisiae

    OpenAIRE

    Pernice, Wolfgang M.; Vevea, Jason D.; Pon, Liza A.

    2016-01-01

    Previous studies indicate that replicative lifespan in daughter cells of Sacchraromyces cerevisiae depends on the preferential inheritance of young, high-functioning mitochondria. We report here that mitochondria are functionally segregated even within single mother cells in S. cerevisiae. A high-functioning population of mitochondria accumulates at the tip of the mother cell distal to the bud. We find that the mitochondrial F-box protein (Mfb1p) localizes to mitochondria in the mother tip an...

  9. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    OpenAIRE

    Wei Luo; Abigail Pulsipher; Debjit Dutta; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-01-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture ...

  10. Reciprocal translocations in Saccharomyces cerevisiae formed by nonhomologous end joining.

    Science.gov (United States)

    Yu, Xin; Gabriel, Abram

    2004-02-01

    Reciprocal translocations are common in cancer cells, but their creation is poorly understood. We have developed an assay system in Saccharomyces cerevisiae to study reciprocal translocation formation in the absence of homology. We induce two specific double-strand breaks (DSBs) simultaneously on separate chromosomes with HO endonuclease and analyze the subsequent chromosomal rearrangements among surviving cells. Under these conditions, reciprocal translocations via nonhomologous end joining (NHEJ) occur at frequencies of approximately 2-7 x 10(-5)/cell exposed to the DSBs. Yku80p is a component of the cell's NHEJ machinery. In its absence, reciprocal translocations still occur, but the junctions are associated with deletions and extended overlapping sequences. After induction of a single DSB, translocations and inversions are recovered in wild-type and rad52 strains. In these rearrangements, a nonrandom assortment of sites have fused to the DSB, and their junctions show typical signs of NHEJ. The sites tend to be between open reading frames or within Ty1 LTRs. In some cases the translocation partner is formed by a break at a cryptic HO recognition site. Our results demonstrate that NHEJ-mediated reciprocal translocations can form in S. cerevisiae as a consequence of DSB repair. PMID:15020464

  11. Neisseria lactamica selectively induces mitogenic proliferation of the naive B cell pool via cell surface Ig.

    Science.gov (United States)

    Vaughan, Andrew T; Brackenbury, Louise S; Massari, Paola; Davenport, Victoria; Gorringe, Andrew; Heyderman, Robert S; Williams, Neil A

    2010-09-15

    Neisseria lactamica is a commensal bacteria that colonizes the human upper respiratory tract mucosa during early childhood. In contrast to the closely related opportunistic pathogen Neisseria meningitidis, there is an absence of adaptive cell-mediated immunity to N. lactamica during the peak age of carriage. Instead, outer membrane vesicles derived from N. lactamica mediate a B cell-dependent proliferative response in mucosal mononuclear cells that is associated with the production of polyclonal IgM. We demonstrate in this study that this is a mitogenic human B cell response that occurs independently of T cell help and any other accessory cell population. The ability to drive B cell proliferation is a highly conserved property and is present in N. lactamica strains derived from diverse clonal complexes. CFSE staining of purified human tonsillar B cells demonstrated that naive IgD(+) and CD27(-) B cells are selectively induced to proliferate by outer membrane vesicles, including the innate CD5(+) subset. Neither purified lipooligosaccharide nor PorB from N. lactamica is likely to be responsible for this activity. Prior treatment of B cells with pronase to remove cell-surface Ig or treatment with BCR-specific Abs abrogated the proliferative response to N. lactamica outer membrane vesicles, suggesting that this mitogenic response is dependent upon the BCR. PMID:20709949

  12. Regulation of mat responses by a differentiation MAPK pathway in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Sheelarani Karunanithi

    Full Text Available Fungal species exhibit diverse behaviors when presented with extracellular challenges. Pathogenic fungi can undergo cell differentiation and biofilm formation in response to fluctuating nutrient levels, and these responses are required for virulence. In the model fungal eukaryote Saccharomyces cerevisiae, nutrient limitation induces filamentous growth and biofilm/mat formation. Both responses require the same signal transduction (MAPK pathway and the same cell adhesion molecule (Flo11 but have been studied under different conditions. We found that filamentous growth and mat formation are aspects of a related response that is regulated by the MAPK pathway. Cells in yeast-form mats differentiated into pseudohyphae in response to nutrient limitation. The MAPK pathway regulated mat expansion (in the plane of the XY-axis and substrate invasion (downward in the plane of the Z-axis, which optimized the mat's response to extracellular nutrient levels. The MAPK pathway also regulated an upward growth pattern (in the plane of the Z-axis in response to nutrient limitation and changes in surface rigidity. Upward growth allowed for another level of mat responsiveness and resembled a type of colonial chemorepulsion. Together our results show that signaling pathways play critical roles in regulating social behaviors in which fungal cells participate. Signaling pathways may regulate similar processes in pathogens, whose highly nuanced responses are required for virulence.

  13. Ca2+ signal is generated only once in the mating pheromone response pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nakajima-Shimada, J; Sakaguchi, S; Tsuji, F I; Anraku, Y; Iida, H

    2000-04-01

    The mating pheromone, alpha-factor, of the yeast Saccharomyces cerevisiae binds to the heterotrimeric G protein-coupled cell surface receptor of MATa cells and induces cellular responses necessary for mating. In higher eukaryotic cells, many hormones and growth factors rapidly mobilize a second messenger, Ca2+, by means of receptor-G protein signaling. Although striking similarities between the mechanisms of the receptor-G protein signaling in yeast and higher eukaryotes have long been known, it is still uncertain whether the pheromone rapidly mobilizes Ca2+ necessary for early events of the pheromone response. Here we reexamine this problem using sensitive methods for detecting Ca2+ fluxes and mobilization, and find no evidence that there is rapid Ca2+ influx leading to a rapid increase in the cytosolic free Ca2+ concentration. In addition, the yeast PLC1 deletion mutant lacking phosphoinositide-specific phospholipase C, a key enzyme for generating Ca2+ signals in higher eukaryotic cells, responds normally to the pheromone. These findings suggest that the receptor-G protein signaling does not utilize Ca2+ as a second messenger in the early stage of the pheromone response pathway. Since the receptor-G protein signaling does stimulate Ca2+ influx after early events have finished and this stimulation is essential for late events in the pheromone response pathway [Iida et al., (1990) J. Biol. Chem., 265: 13391-13399] Ca2+ may be used only once in the signal transduction pathway in unicellular eukaryotes such as yeast. PMID:10885582

  14. Surface Properties of Cell-treated Polyethylene Terephthalate

    Directory of Open Access Journals (Sweden)

    Bing Shi

    2006-01-01

    Full Text Available The materials used in artificial joints undergo degradation through fatigue and corrosive wear in human body. The lifetime for well-designed artificial joints like hip joints is at most 12 years and a patient will usually have two total joint replacements during his/her lifetime. Tissue engineering, an alternative to total joint implantation, is the replacement of damaged tissue with the tissue that is designed and constructed to meet the needs of the individual patient. In this study, polyethylene terephthalate (PET in the form of overhead transparency films were investigated on their cell interactions and the tribological properties as an alternative tissue-engineering matrix. The base material of the transparency films is PET. Cell culture methods as well as atomic force microscope (AFM, contact angle goniometer, confocal microscope and universal tribotester were used to study the properties of the substrate materials and the interactions between the surface and the substrate materials. Results showed that cells grew on the substrate of the base materials of the PET. The tribological properties of the slides have been changed after being cell-treated.

  15. Control of cell behavior on PTFE surface using ion beam irradiation

    International Nuclear Information System (INIS)

    A polytetrafluoroethylene (PTFE) surface is smooth and biologically inert, so that cells cannot attach to it. Ion beam irradiation of the PTFE surface forms micropores and a melted layer, and the surface is finally covered with a large number of small protrusions. Recently, we found that cells could adhere to this irradiated PTFE surface and spread over the surface. Because of their peculiar attachment behavior, these surfaces can be used as biological tools. However, the factors regulating cell adhesion are still unclear, although some new functional groups formed by irradiation seem to contribute to this adhesion. To control cell behavior on PTFE surfaces, we must determine the effects of the outermost irradiated surface on cell adhesion. In this study, we removed the thin melted surface layer by postirradiation annealing and investigated cell behavior on the surface. On the surface irradiated with 3 x 1016 ions/cm2, cells spread only on the remaining parts of the melted layer. From these results, it is clear that the melted layer had a capacity for cell attachment. When the surface covered with protrusions was irradiated with a fluence of 1 x 1017 ions/cm2, the distribution of cells changed after the annealing process from 'sheet shaped' into multicellular aggregates with diameters of around 50 μm. These results indicate that we can control cell behavior on PTFE surfaces covered with protrusions using irradiation and subsequent annealing. Multicellular spheroids can be fabricated for tissue engineering using this surface.

  16. Cell shape and spreading of stromal (mesenchymal) stem cells cultured on fibronectin coated gold and hydroxyapatite surfaces

    DEFF Research Database (Denmark)

    Dolatshahi-Pirouz, A; Jensen, Thomas Hartvig Lindkjær; Kolind, Kristian;

    2011-01-01

    concentration. In subsequent cell studies with hMSC's we studied the cell spreading, cytoskeletal organization and cell morphology on the respective surfaces. When the cells were adsorbed on the uncoated substrates, a diffuse cell actin cytoskeleton was revealed, and the cells had a highly elongated shape. On...... observed on HA as compared to Au. Moreover, the results revealed that the morphology of cells cultured on fibronectin coated HA surfaces were less irregular. In summary we find that fibronectin adsorbs in a more activated state on the HA surfaces, resulting in a slightly different cellular response as...

  17. Mechanism of uranium(VI) uptake by Saccharomyces cerevisiae under environmentally relevant conditions: Batch, HRTEM, and FTIR studies

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xia, E-mail: lux2009@lzu.edu.cn; Zhou, Xiao-jiao; Wang, Tie-shan, E-mail: tswang@lzu.edu.cn

    2013-11-15

    Highlights: • Equilibrium reaches very rapid within 15 min. • pH shift towards neutral indicates release of hydroxyl ions. • High ionic strength inhabits biosorption capacity. • Uptake capacity of heat-killed cells is an order of magnitude higher than live one. • Electrostatic interaction, precipitation, and complexation are the main mechanisms. -- Abstract: Biosorption is of significance for the safety evaluation of high-level nuclear wastes repositories and remediation of radioactive contamination places. Quantitive study and structural characterization of uranium uptake by both live and heat-killed Saccharomyces cerevisiae at environmentally relevant uranium concentration and with different ionic strengths were carried out. Kinetic investigation showed the equilibrium reached within 15 min. In equilibrium studies, pH shift towards neutral indicated release of hydroxyl ions. pH was the most important factor, which partly affected electrostatic interaction between uranyl ions and S. cerevisiae surface. The high ionic strength inhibited biosorption capacity, which can be explained by a competitive reaction between sodium ions and uranyl ions. Heat killing process significantly enhanced biosorption capacity, showing an order of magnitude higher than that of live cells. High resolution transmission electron microscopy (HRTEM) coupled with energy dispersive X-ray (EDX) showed needle-like uranium-phosphate precipitation formed on the cell walls for both live and heat-killed cells. Besides, dark-field micrographs displayed considerable similar uranium-phosphate precipitation presented outside the heat-killed cells. The phosphate released during heat-killing process. FTIR illustrated function groups hydroxyl, carboxyl, phosphate, and amino groups played important role in complexation with uranium.

  18. Association of cell surface heparan sulfate proteoglycans of Schwann cells with extracellular matrix proteins.

    Science.gov (United States)

    Carey, D J; Crumbling, D M; Stahl, R C; Evans, D M

    1990-11-25

    The terminal differentiation of Schwann cells is dependent on contact with basement membrane. The present study was undertaken to investigate the role of cell surface heparan sulfate proteoglycans (HSPGs) in mediating Schwann cell responses to extracellular matrix contact. Phosphatidylinositol-specific phospholipase C-releasable cell surface HSPGs purified from cultures of neonatal rat Schwann cells were subjected to affinity chromatography on immobilized laminin and fibronectin. Binding of the HSPG to both affinity matrices was observed. The strength of the association, however, was sensitive to the ionic strength of the buffer. In 0.1 M Tris-HCl, HSPG binding was essentially irreversible whereas in physiological ionic strength buffer (e.g. 0.142 M NaCl, 10 mM Tris), weaker binding was detected as a delay in elution of the HSPG from the affinity columns. Further studies of HSPG-laminin binding suggested that the binding was mediated by the glycosaminoglycan chains of the proteoglycans. Results of equilibrium gel filtration chromatography provided additional evidence for a reversible association of the HSPG and laminin with a Kd of approximately 1 x 10(-6) M. When Schwann cells were plated on plastic dishes coated with laminin, the cells attached and extended long slender processes. Inclusion of heparin, but not chondroitin sulfate, in the assay medium resulted in partial inhibition of process extension, but at concentrations of heparin which were higher than that needed to disrupt laminin-HSPG association in vitro. Addition of anti-integrin receptor antibodies resulted in more extensive inhibition of laminin-dependent process extension. Anti-integrin antibodies plus heparin essentially totally inhibited laminin-dependent process extension. These results demonstrate that cell surface HSPGs are capable of reversible association with extracellular matrix molecules and suggest that HSPG-laminin interactions play a role in laminin-dependent Schwann cell spreading. PMID

  19. Characterization of the Viable but Nonculturable (VBNC State in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Mohammad Salma

    Full Text Available The Viable But Non Culturable (VBNC state has been thoroughly studied in bacteria. In contrast, it has received much less attention in other microorganisms. However, it has been suggested that various yeast species occurring in wine may enter in VBNC following sulfite stress.In order to provide conclusive evidences for the existence of a VBNC state in yeast, the ability of Saccharomyces cerevisiae to enter into a VBNC state by applying sulfite stress was investigated. Viable populations were monitored by flow cytometry while culturable populations were followed by plating on culture medium. Twenty-four hours after the application of the stress, the comparison between the culturable population and the viable population demonstrated the presence of viable cells that were non culturable. In addition, removal of the stress by increasing the pH of the medium at different time intervals into the VBNC state allowed the VBNC S. cerevisiae cells to "resuscitate". The similarity between the cell cycle profiles of VBNC cells and cells exiting the VBNC state together with the generation rate of cells exiting VBNC state demonstrated the absence of cellular multiplication during the exit from the VBNC state. This provides evidence of a true VBNC state. To get further insight into the molecular mechanism pertaining to the VBNC state, we studied the involvement of the SSU1 gene, encoding a sulfite pump in S. cerevisiae. The physiological behavior of wild-type S. cerevisiae was compared to those of a recombinant strain overexpressing SSU1 and null Δssu1 mutant. Our results demonstrated that the SSU1 gene is only implicated in the first stages of sulfite resistance but not per se in the VBNC phenotype. Our study clearly demonstrated the existence of an SO2-induced VBNC state in S. cerevisiae and that the stress removal allows the "resuscitation" of VBNC cells during the VBNC state.

  20. Engineered antifouling microtopographies: surface pattern effects on cell distribution.

    Science.gov (United States)

    Decker, Joseph T; Sheats, Julian T; Brennan, Anthony B

    2014-12-23

    Microtopography has been observed to lead to altered attachment behavior for marine fouling organisms; however, quantification of this phenomenon is lacking in the scientific literature. Here, we present quantitative measurement of the disruption of normal attachment behavior of the fouling algae Ulva linza by antifouling microtopographies. The distribution of the diatom Navicula incerta was shown to be unaffected by the presence of topography. The radial distribution function was calculated for both individual zoospores and cells as well as aggregates of zoospores from attachment data for a variety topographic configurations and at a number of different attachment densities. Additionally, the screening distance and maximum values were mapped according to the location of zoospore aggregates within a single unit cell. We found that engineered topographies decreased the distance between spore aggregates compared to that for a smooth control surface; however, the distributions for individual spores were unchanged. We also found that the local attachment site geometry affected the screening distance for aggregates of zoospores, with certain geometries decreasing screening distance and others having no measurable effect. The distribution mapping techniques developed and explored in this article have yielded important insight into the design parameters for antifouling microtopographies that can be implemented in the next generation of antifouling surfaces. PMID:25420235

  1. Expression of the major heat shock gene of Drosophila melanogaster in Saccharomyces cerevisiae.

    OpenAIRE

    de Banzie, J S; Sinclair, L; Lis, J T

    1986-01-01

    A copy of the gene which encodes the major heat shock protein (hsp70) of D. melanogaster was integrated in both orientations into the genome of S. cerevisiae at the leu2 locus. The level of transcript from the D. melanogaster gene was measured under both normal conditions and conditions which are known to give rise to the heat shock response in S. cerevisiae. In both orientations the D. melanogaster gene gave rise to an abundant transcript in uninduced cells. The level of this transcript was ...

  2. Individual-based observations and individual-based simulations to study Saccharomyces cerevisiae cultures

    OpenAIRE

    Portell Canal, Xavier

    2014-01-01

    Tesi per compendi de publicacions. La consulta íntegra de la tesi, inclosos els articles no comunicats públicament per drets d'autor, es pot realitzar prèvia petició a l'Arxiu de la UPC Saccharomyces cerevisiae is one of the yeasts with major economic, social, and health significance in human culture. Depending on the growth conditions experienced by the cell, S. cerevisiae growth can proceed via fermentative, respirative, or respirofermentative metabolism. Scar formation, unequal division...

  3. Engineering Cell Instructive Materials To Control Cell Fate and Functions through Material Cues and Surface Patterning.

    Science.gov (United States)

    Ventre, Maurizio; Netti, Paolo A

    2016-06-22

    Mastering the interaction between cells and extracellular environment is a fundamental prerequisite in order to engineer functional biomaterial interfaces able to instruct cells with specific commands. Such advanced biomaterials might find relevant application in prosthesis design, tissue engineering, diagnostics and stem cell biology. Because of the highly complex, dynamic, and multifaceted context, a thorough understanding of the cell-material crosstalk has not been achieved yet; however, a variety of material features including biological cues, topography, and mechanical properties have been proved to impact the strength and the nature of the cell-material interaction, eventually affecting cell fate and functions. Although the nature of these three signals may appear very different, they are equated by their participation in the same material-cytoskeleton crosstalk pathway as they regulate cell adhesion events. In this work we present recent and relevant findings on the material-induced cell responses, with a particular emphasis on how the presentation of biochemical/biophysical signals modulates cell behavior. Finally, we summarize and discuss the literature data to draw out unifying elements concerning cell recognition of and reaction to signals displayed by material surfaces. PMID:26693600

  4. Cellular and molecular engineering of yeast Saccharomyces cerevisiae for advanced biobutanol production.

    Science.gov (United States)

    Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-02-01

    Butanol is an attractive alternative energy fuel owing to several advantages over ethanol. Among the microbial hosts for biobutanol production, yeast Saccharomyces cerevisiae has a great potential as a microbial host due to its powerful genetic tools, a history of successful industrial use, and its inherent tolerance to higher alcohols. Butanol production by S. cerevisiae was first attempted by transferring the 1-butanol-producing metabolic pathway from native microorganisms or using the endogenous Ehrlich pathway for isobutanol synthesis. Utilizing alternative enzymes with higher activity, eliminating competitive pathways, and maintaining cofactor balance achieved significant improvements in butanol production. Meeting future challenges, such as enhancing butanol tolerance and implementing a comprehensive strategy by high-throughput screening, would further elevate the biobutanol-producing ability of S. cerevisiae toward an ideal microbial cell factory exhibiting high productivity of biobutanol. PMID:26712533

  5. Surface charge characteristics of cells from malignant cell lines and normal cell lines of the human hematopoietic system.

    Science.gov (United States)

    Marikovsky, Y; Ben-Bassat, H; Leibovich, S J; Cividalli, L; Fischler, H; Danon, D

    1979-02-01

    Cells from malignant and normal lines of human hematopoietic origin were studied for their surface charge characteristics with the use of the following criteria: 1) the electron microscopic appearance of cell membranes after labeling with cationized ferritin (CF) either before or after glutaraldehyde fixation, 2) electrophoretic mobility, 3) total sialic acid content, and 4) agglutinability with poly-L-lysine (PLL). CF induced a time-dependent redistribution of surface receptors in unfixed malignant cells but not in unfixed normal cells. After 10 seconds of labeling with CF, both normal and malignant unfixed cells showed a uniform and even labeling pattern. After 5 minutes of labeling, malignant cells exhibited a highly pronounced pattern of clusters and patches, as distinct from a random and even pattern exhibited by normal cells. Both normal and malignant cells after fixation exhibited an equivalent random and even labeling pattern with CF, independent of the duration of labeling. The malignant cells studied possessed less sialic acid, had a lower electric mobility, and were agglutinated more readily with PLL than were the normal cells. PMID:310907

  6. Distribution of Prestin on Outer Hair Cell Basolateral Surface

    Institute of Scientific and Technical Information of China (English)

    YU Ning; ZHAI Suo-qiang; YANG Shi-ming; HAN Dong-yi; ZHAO Hong-bo

    2008-01-01

    Prestin has been identified as a motor protein responsible for outer hair cell (OHC) electromotility and is expressed on the OHC surface. Previous studies revealed that OHC eleetromotility and its associated nonlinear capacitance were mainly located at the OHC lateral wall and absent at the apical cutieular plate and the basal nucleus region. Immunofluorescent staining for prestin also failed to demonstrate prestin expression at the OHC basal ends in whole-mount preparation of the organ of Corti. However, there lacks a definitive demonstration of the pattern of prestin distribution. The OHC lateral wall has a trilaminate organization and is composed of the plasma membrane, cortical lattice, and subsurface cisternae. In this study, the location of prestin proteins in dissociated OHCs was examined using immunofluorescent staining and confocal microscopy. We found that prestin was uniformly expressed on the basolateral surface, including the basal pole. No staining was seen on the cuticular plate and stereocilia. When co-stained with a membrane marker di-8-ANEPPS, prestin-labeling was found to be in the outer layer of the OHC lateral wall. After separating the plasma membrane from the underlying subsurface eisternae using a hypotonic extracellular solution, prestin-labeling was found to be in the plasma membrane, not the subsurface cisternae. The data show that prestin is expressed in the plasma membrane on the entire OHC basolateral surface.

  7. Surface Analyses and Immune Reactivities of Major Cell Wall-Associated Proteins of Group A Streptococcus

    OpenAIRE

    Cole, Jason N; Ramirez, Ruben D.; Currie, Bart J.; Cordwell, Stuart J.; Djordjevic, Steven P.; Mark J Walker

    2005-01-01

    A proteomic analysis was undertaken to identify cell wall-associated proteins of Streptococcus pyogenes. Seventy-four distinct cell wall-associated proteins were identified, 66 of which were novel. Thirty-three proteins were immunoreactive with pooled S. pyogenes-reactive human antisera. Biotinylation of the GAS cell surface identified 23 cell wall-associated proteins that are surface exposed.

  8. Large-scale evaluation of in silico gene deletions in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Förster, Jochen; Famili, Iman; Palsson, Bernhard Ø;

    2003-01-01

    A large-scale in silico evaluation of gene deletions in Saccharomyces cerevisiae was conducted using a genome-scale reconstructed metabolic model. The effect of 599 single gene deletions on cell viability was simulated in silico and compared to published experimental results. In 526 cases (87...

  9. Growth-rate regulated genes have profound impact on interpretation of transcriptome profiling in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Regenberg, Birgitte; Grotkjaer, Thomas; Winther, Ole;

    2006-01-01

    Growth rate is central to the development of cells in all organisms. However, little is known about the impact of changing growth rates. We used continuous cultures to control growth rate and studied the transcriptional program of the model eukaryote Saccharomyces cerevisiae, with generation times...

  10. Saccharomyces cerevisiae of palm wine-enhanced ethanol production by using mutagens

    International Nuclear Information System (INIS)

    The newly isolated Saccharomyces cerevisiae of palm wine produced enhanced amounts of ethanol when cells were UV-irradiated and treated with N-methyl-N-nitro-N-nitrosoguanidine. A further increase of ethanol was observed in yeast extract, peptone, dextrose medium fortified with yeast extract, skimmed milk and soya flour. (author). 9 refs

  11. High expression of heterologous proteins by Saccharomyces cerevisiae grown on ethanol

    NARCIS (Netherlands)

    Laar, Antonius Martinus Johannes van de

    2006-01-01

    The production of recombinant proteins is of great importance for industrial applications in fields such as pharmaceutical ingredients and industrial enzymes. One of these products are camelid antibody fragments, produced by Saccharomyces cerevisiae in high cell density fed batch fermentation proces

  12. Regulation of ADAM12 cell-surface expression by protein kinase C epsilon

    DEFF Research Database (Denmark)

    Sundberg, Christina; Thodeti, Charles Kumar; Kveiborg, Marie;

    2004-01-01

    constitutively active protein. However, little is known about the regulation of ADAM12 cell-surface translocation. Here, we used human RD rhabdomyosarcoma cells, which express ADAM12 at the cell surface, in a temporal pattern. We report that protein kinase C (PKC) epsilon induces ADAM12 translocation to the cell......The ADAM (a disintegrin and metalloprotease) family consists of multidomain cell-surface proteins that have a major impact on cell behavior. These transmembrane-anchored proteins are synthesized as proforms that have (from the N terminus): a prodomain; a metalloprotease-, disintegrin......-immunoprecipitated from membrane-enriched fractions of PMA-treated cells, 3) RD cells transfected with EGFP-tagged, myristoylated PKCepsilon expressed more ADAM12 at the cell surface than did non-transfected cells, and 4) RD cells transfected with a kinase-inactive PKCepsilon mutant did not exhibit ADAM12 cell...

  13. Data on dynamic study of cytoophidia in Saccharomyces cerevisiae.

    Science.gov (United States)

    Li, Hui; Huang, Yong; Wang, Peng-Ye; Ye, Fangfu; Liu, Ji-Long

    2016-09-01

    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(09)60046-1) 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. PMID:27274529

  14. 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.

  15. Galectin-1-mediated cell adhesion, invasion and cell death in human anaplastic large cell lymphoma: regulatory roles of cell surface glycans.

    Science.gov (United States)

    Suzuki, Osamu; Abe, Masafumi

    2014-05-01

    Galectin-1 is known to be one of the extracellular matrix proteins. To elucidate the biological roles of galectin-1 in cell adhesion and invasion of human anaplastic large cell lymphoma, we performed cell adhesion and invasion assays using the anaplastic large cell lymphoma cell line H-ALCL, which was previously established in our laboratory. From the cell surface lectin array, treatment with neuraminidase from Arthrobacter ureafaciens which cleaves all linkage types of cell surface sialic acid enhanced Arachis hypogaea (PNA), Helix pomatia (HPA) and Phaseolus vulgaris-L (L-PHA) lectin binding reactivity to cell surface of lymphoma cells suggesting that neuraminidase removes cell surface sialic acid. In cell adhesion and invasion assays treatment with neuraminidase markedly enhanced cell adhesion to galectin-1 and decreased cell invasive capacity through galectin-1. α2,6-linked sialic acid may be involved in masking the effect of the interaction between galectin-1 and cell surface glycans. H-ALCL cells expressed the β-galactoside-α2,6-sialyltransferase ST6Gal1. On resialylation assay by recombinant ST6Gal1 with CMP-Neu5Ac, α2,6-resialylation of L-PHA reactive oligosaccharide by ST6Gal1 resulted in inhibition of H-ALCL cell adhesion to galectin-1 compared to the desialylated H-ALCL cells. On knockdown experiments, knockdown of ST6Gal1 dramatically enhanced cell adhesion to galectin-1. N-glycosylation inhibitor swainsonine treatment resulted in enhancement of cell adhesion to galectin-1. In glycomic analysis using the lectin blocking assay treatment with PNA, Artocarpus integrifolia (Jacalin), Glycine max (SBA), Helix pomatia (HPA), Vicia villosa (VVA), Ulex europaeus (UEA-1), Triticum vulgaris (WGA), Canavalia ensiformis (ConA), Phaseolus vulgaris-L (L-PHA), Phaseolus vulgaris-E4 (E-PHA), Datura stramonium (DSA) lectins resulted in modulation of lymphoma cell to galectin-1 suggesting that several types of glycans may regulate cell adhesion to galectin-1 by

  16. Locally contacted rear surface passivated solar cells by inkjet printing

    Science.gov (United States)

    Phiwpha, N.; Fangsuwannarak, T.; Sopitpan, S.

    2014-06-01

    Inkjet printing of photoresist material may provide a new route for low-cost fabrication of patterned oxide passivation layer of solar cells that require fine patterning and simple process. However, printing by liquid-based, environmentally friendly ink and printing device required development efforts aimed at achieving a fine patterning and long used inkjet nozzles under corrosive influence. This work was demonstrated a concept for grooved silicon oxide patterning for rear localized contact of p-n junction solar cells by chemical etching after photoresist patterning obtained. This article reviews the silicon dioxide fabrication on p-Si substrate from sol-gel technique for oxide passivation layer of solar cells. The aluminium was deposited on the patterned oxide layer and then heated at its Al-Si eutectic temperature. Finally, an aluminium-induced solid-phase epitaxial growth of p+ forming into the openings of the oxide passivation layer was presented. The sheet resistance of n-emitter layer, carrier life-time and surface recombination velocity values are investigated. Photoconductive measurements were performed on the prepared samples after each thermal process to measure the effective lifetime of the minority carriers. Carrier lifetime up to 60 microseconds has been measured on c-Si wafer passivated by the opened SiO2 layer. It was shown that the patterned SiO2 passivation has obtained high passivation quality making by the proposed inkjet printing method.

  17. Compositions and methods for modeling Saccharomyces cerevisiae metabolism

    DEFF Research Database (Denmark)

    2012-01-01

    The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S. cerevisiae reactants to a plurality of S. cerevisiae reactions, a constraint set for the plurality of S. cerevisiae reactions, and...... commands for determining a distribution of flux through the reactions that is predictive of a S. cerevisiae physiological function. A model of the invention can further include a gene database containing information characterizing the associated gene or genes. The invention further provides methods for...... making an in silica S. cerevisiae model and methods for determining a S. cerevisiae physiological function using a model of the invention. The invention provides an in silica model for determining a S. cerevisiae physiological function. The model includes a data structure relating a plurality of S...

  18. Cell surface N-glycans influence the level of functional E-cadherin at the cell–cell border

    OpenAIRE

    M Kristen Hall; Douglas A Weidner; Sahil Dayal; Ruth A. Schwalbe

    2014-01-01

    E-cadherin is crucial for adhesion of cells to each other and thereby development and maintenance of tissue. While it is has been established that N-glycans inside the cell impact the level of E-cadherin at the cell surface of epithelial-derived cells, it is unclear whether N-glycans outside the cell control the clustering of E-cadherin at the cell–cell border. Here, we demonstrate reduction of N-glycans at the cell surface weakened the recruitment and retention of E-cadherin at the cell–cell...

  19. Cell surface glycan alterations in epithelial mesenchymal transition process of Huh7 hepatocellular carcinoma cell.

    Directory of Open Access Journals (Sweden)

    Shan Li

    Full Text Available BACKGROUND AND OBJECTIVE: Due to recurrence and metastasis, the mortality of Hepatocellular carcinoma (HCC is high. It is well known that the epithelial mesenchymal transition (EMT and glycan of cell surface glycoproteins play pivotal roles in tumor metastasis. The goal of this study was to identify HCC metastasis related differential glycan pattern and their enzymatic basis using a HGF induced EMT model. METHODOLOGY: HGF was used to induce HCC EMT model. Lectin microarray was used to detect the expression of cell surface glycan and the difference was validated by lectin blot and fluorescence cell lectin-immunochemistry. The mRNA expression levels of glycotransferases were determined by qRT-PCR. RESULTS: After HGF treatment, the Huh7 cell lost epithelial characteristics and obtained mesenchymal markers. These changes demonstrated that HGF could induce a typical cell model of EMT. Lectin microarray analysis identified a decreased affinity in seven lectins ACL, BPL, JAC, MPL, PHA-E, SNA, and SBA to the glycan of cell surface glycoproteins. This implied that glycan containing T/Tn-antigen, NA2 and bisecting GlcNAc, Siaα2-6Gal/GalNAc, terminal α or βGalNAc structures were reduced. The binding ability of thirteen lectins, AAL, LCA, LTL, ConA, NML, NPL, DBA, HAL, PTL II, WFL, ECL, GSL II and PHA-L to glycan were elevated, and a definite indication that glycan containing terminal αFuc and ± Sia-Le, core fucose, α-man, gal-β(α GalNAc, β1,6 GlcNAc branching and tetraantennary complex oligosaccharides structures were increased. These results were further validated by lectin blot and fluorescence cell lectin-immunochemistry. Furthermore, the mRNA expression level of Mgat3 decreased while that of Mgat5, FucT8 and β3GalT5 increased. Therefore, cell surface glycan alterations in the EMT process may coincide with the expression of glycosyltransferase. CONCLUSIONS: The findings of this study systematically clarify the alterations of cell surface

  20. Studies on cell adhesion and recognition. II. The kinetics of cell adhesion and cell spreading on surfaces coated with carbohydrate- reactive proteins (glycosidases and lectins) and fibronectin

    OpenAIRE

    1981-01-01

    The kinetics of cell attachment and cell spreading on the coated surfaces of two classes of carbohydrate-reactive proteins, enzymes and lectins, have been compared with those on fibronectin-coated surfaces with the following results: (a) A remarkable similarity between the kinetics of cell attachment to fibronectin-coated and glycosidase- coated surfaces was found. In contrast, cell attachment kinetics induced by lectin- and galactose oxidase-coated surfaces, in general, were strikingly diffe...

  1. Interaction of progenitor bone cells with different surface modifications of titanium implant

    International Nuclear Information System (INIS)

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  2. Interaction of progenitor bone cells with different surface modifications of titanium implant

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chen, Ya-Shun [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Lin, Yi; Kuo, Tzu-Huang; Kuo, Hsien-Nan [Medical Device Development Division, Metal Industries Research and Development Centre, Kaohsiung 82151, Taiwan (China)

    2014-04-01

    Changes in the physical and chemical properties of Ti surfaces can be attributed to cell performance, which improves surface biocompatibility. The cell proliferation, mineralization ability, and gene expression of progenitor bone cells (D1 cell) were compared on five different Ti surfaces, namely, mechanical grinding (M), electrochemical modification through potentiostatic anodization (ECH), sandblasting and acid etching (SLA), sandblasting, hydrogen peroxide treatment, and heating (SAOH), and sandblasting, alkali heating, and etching (SMART). SAOH treatment produced the most hydrophilic surface, whereas SLA produced the most hydrophobic surface. Cell activity indicated that SLA and SMART produced significantly rougher surfaces and promoted D1 cell attachment within 1 day of culturing, whereas SAOH treatment produced moderate roughness (Ra = 1.26 μm) and accelerated the D1 cell proliferation up to 7 days after culturing. The ECH surface significantly promoted alkaline phosphatase (ALP) expression and osteocalcin (OCN) secretion in the D1 cells compared with the other surface groups. The ECH and SMART-treated Ti surfaces resulted in maximum ALP and OCN expressions during the D1 cell culture. SLA, SAOH, and SMART substrate surfaces were rougher and exhibited better cell metabolic responses during the early stage of cell attachment, proliferation, and morphologic expressions within 1 day of D1 cell culture. The D1 cells cultured on the ECH and SMART substrates exhibited higher differentiation, and higher ALP and OCN expressions after 10 days of culture. Thus, the ECH and SMART treatments promote better ability of cell mineralization in vitro, which demonstrate their great potential for clinical use. - Highlights: • Progenitor bone cells onto Ti with different modifications are characterized. • Surface roughness and hydrophilicity encourage early stage cell attachment. • Composition and surface treatments are more vital in bone cell mineralization.

  3. Evaluation of apoptosis and necrosis in Saccharomyces cerevisiae during wine fermentations

    OpenAIRE

    Salvador, Vanessa Alexandra Guerreiro

    2009-01-01

    During wine fermentation the yeast cells are affected by several stress conditions in different phases of the fermentation process, which induces deeply changes in yeast cells physiology. The aim of this work was to evaluate different parameters related to the physiological state of an industrial strain of Saccharomyces cerevisiae (ISA1000), during wine fermentations of white grape must, 15ºC and 30ºC, simulating winery conditions. As indicator of the number of viable cells and...

  4. Integrin binding specificity regulates biomaterial surface chemistry effects on cell differentiation

    OpenAIRE

    Keselowsky, Benjamin G.; Collard, David M.; Andrés J. García

    2005-01-01

    Biomaterial surface chemistry has profound consequences on cellular and host responses, but the underlying molecular mechanisms remain poorly understood. Using self-assembled monolayers as model biomaterial surfaces presenting well defined chemistries, we demonstrate that surface chemistry modulates osteoblastic differentiation and matrix mineralization independently from alterations in cell proliferation. Surfaces were precoated with equal densities of fibronectin (FN), and surface chemistry...

  5. Cell adhesion behavior on the silicone rubber surface modified by using ion beam irradiation

    International Nuclear Information System (INIS)

    In this study we studied cell adhesion and proliferation on the surface of a silicone rubber modified by ion beam irradiation. The surface property of the irradiated silicone rubber was characterized by water contact angle and FT-IR analyses. It was observed that human (HEK293) fibroblast cells exhibit strong adhesion to the irradiated silicone surface. This enhanced adhesion of mammalian cells can be attributed to the increase in the hydrophilicity of the silicone surface by ion beam irradiation

  6. Impaired cell surface expression of HLA-B antigens on mesenchymal stem cells and muscle cell progenitors

    DEFF Research Database (Denmark)

    Isa, Adiba; Nehlin, Jan; Sabir, Hardee Jawad;

    2010-01-01

    HLA class-I expression is weak in embryonic stem cells but increases rapidly during lineage progression. It is unknown whether all three classical HLA class-I antigens follow the same developmental program. In the present study, we investigated allele-specific expression of HLA-A, -B, and -C...... at the mRNA and protein levels on human mesenchymal stem cells from bone marrow and adipose tissue as well as striated muscle satellite cells and lymphocytes. Using multicolour flow cytometry, we found high cell surface expression of HLA-A on all stem cells and PBMC examined. Surprisingly, HLA-B was either...... undetectable or very weakly expressed on all stem cells protecting them from complement-dependent cytotoxicity (CDC) using relevant human anti-B and anti-Cw sera. IFNgamma stimulation for 48-72 h was required to induce full HLA-B protein expression. Quantitative real-time RT-PCR showed that IFNgamma induced...

  7. Cell surface modulation of gene expression in brain cells by down regulation of glucocorticoid receptors

    Energy Technology Data Exchange (ETDEWEB)

    McGinnis, J.F.; de Vellis, J.

    1981-02-01

    The concentration of glycerol-3-phosphate dehydrogenase (GPDH; sn-glycerol-3-phosphate:NAD/sup +/ 2-oxidoreductase, EC 1.1.1.8) had previously been determined to be regulated by glucocorticoids in rat brain cells in vivo and in cell culture. We now demonstrate that concanavalin A (Con A) can inhibit the induction of GPDH in a dose-dependent manner in C6 rat glioma cells and in primary cultures of rat brain oligodendrocytes. The inhibition specifically prevents the appearance of new molecules of GPDH, although Con A does not significantly inhibit protein synthesis in these cells, nor does it affect the activity of another solube enzyme, lactate dehydrogenase. The ability to block enzyme induction is not limited to Con A, because other lectins also inhibit induction. The molecular mechanism by which Con A inhibits GPDH induction appears to be by the down regulation of the cytoplasmic glucocorticoid receptors, because exposure to Con A results in the loss of more than 90% of the receptor activity. Con A does not inhibit the receptor assay and no direct interaction between the receptor and Con A could be demonstrated. This down regulation is not tumor cell specific and appears to be a general phenomenon, because it occurs in normal oligodendrocytes and even in normal astrocytes (a cell type in which the gene for GPDH is not expressed). The down regulation of glucocorticoid receptors in normal brain cells suggests two important corollaries. First, it demonstrates the existence of a rate-limiting step controlling the glucocorticoid-dependent gene expression in brain cells and possibly represents a regulatory site common to all glucocorticoid target cells. Second, it suggests that the response to glucocorticoids of oligodendrocytes and astrocytes can be regulated in vivo by cell surface contact with endogenous lectins, neighboring cells, or both.

  8. Characteristics of Zn2+ Biosorption by Saccharomyces cerevisiae

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the characteristics of Zn2+ biosorption and the release of cations during the process of Zn2+biosorption by intact cells of Saccharomyces cerevisiae. Methods The batch adsorption test was used to study the biosorption equilibrium and isotherm. Zn2+ concentration was measured with atomic adsorption spectrophotometer (AAS) AAS 6.Vario. Results When the initial concentration of Zn2+ ranged between 0.08 and 0.8 mmol/L, the initial pH was natural (about 5.65), the sorbent concentration was about 1 g/L and the capacity of Zn2+ biosorption was from 74.8 to 654.8 μmol/g. The pH value increased by 0.55-1.28 and the intracellular cations (K+, Mg2+, Na+, Ca2+) of the cells were released during the process of Zn2+ biosorption. Conclusion Ion exchange was one of the mechanisms for Zn2+ biosorption. The biomass of Saccharomyces cerevisiae is a potential biosorbent for the removal of Zn2+ from aqueous solution. More work needs to be done before putting it into practical application.

  9. Metabolomic approach for improving ethanol stress tolerance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Ohta, Erika; Nakayama, Yasumune; Mukai, Yukio; Bamba, Takeshi; Fukusaki, Eiichiro

    2016-04-01

    The budding yeast Saccharomyces cerevisiae is widely used for brewing and ethanol production. The ethanol sensitivity of yeast cells is still a serious problem during ethanol fermentation, and a variety of genetic approaches (e.g., random mutant screening under selective pressure of ethanol) have been developed to improve ethanol tolerance. In this study, we developed a strategy for improving ethanol tolerance of yeast cells based on metabolomics as a high-resolution quantitative phenotypic analysis. We performed gas chromatography-mass spectrometry analysis to identify and quantify 36 compounds on 14 mutant strains including knockout strains for transcription factor and metabolic enzyme genes. A strong relation between metabolome of these mutants and their ethanol tolerance was observed. Data mining of the metabolomic analysis showed that several compounds (such as trehalose, valine, inositol and proline) contributed highly to ethanol tolerance. Our approach successfully detected well-known ethanol stress related metabolites such as trehalose and proline thus, to further prove our strategy, we focused on valine and inositol as the most promising target metabolites in our study. Our results show that simultaneous deletion of LEU4 and LEU9 (leading to accumulation of valine) or INM1 and INM2 (leading to reduction of inositol) significantly enhanced ethanol tolerance. This study shows the potential of the metabolomic approach to identify target genes for strain improvement of S. cerevisiae with higher ethanol tolerance. PMID:26344121

  10. Human epithelial cells exposed to functionalized multiwalled carbon nanotubes: interactions and cell surface modifications.

    Science.gov (United States)

    Fanizza, C; Casciardi, S; Incoronato, F; Cavallo, D; Ursini, C L; Ciervo, A; Maiello, R; Fresegna, A M; Marcelloni, A M; Lega, D; Alvino, A; Baiguera, S

    2015-09-01

    With the expansion of the production and applications of multiwalled carbon nanotubes (MWCNTs) in several industrial and science branches, the potential adverse effects on human health have attracted attention. Numerous studies have been conducted to evaluate how chemical functionalization may affect MWCNT effects; however, controversial data have been reported, showing either increased or reduced toxicity. In particular, the impact of carboxylation on MWCNT cytotoxicity is far from being completely understood. The aim of this work was the evaluation of the modifications induced by carboxylated-MWCNTs (MWCNTs-COOH) on cell surface and the study of cell-MWCNT-COOH interactions by means of field emission scanning electron microscope (FESEM). Human pulmonary epithelial cells (A549) were incubated with MWCNTs-COOH for different exposure times and concentrations (10 μg/mL for 1, 2, 4 h; 5, 10, 20 μg/mL for 24 h). At short incubation time, MWCNTs-COOH were easily observed associated with plasma membrane and in contact with microvilli. After 24 h exposure, FESEM analysis revealed that MWCNTs-COOH induced evident changes in the cellular surface in comparison to control cells: treated cells showed blebs, holes and a depletion of the microvilli density in association with structure modifications, such as widening and/or lengthening. In particular, an increase of cells showing holes and microvilli structure alterations was observed at 20 μg/mL concentration. FESEM analysis showed nanotube agglomerates, of different sizes, entering into the cell with two different mechanisms: inward bending of the membrane followed by nanotube sinking, and nanotube internalization directly through holes. The observed morphological microvilli modifications, induced by MWCNTs-COOH, could affect epithelial functions, such as the control of surfactant production and secretion, leading to pathological conditions, such as alveolar proteinosis. More detailed studies will be, however, necessary to

  11. Micropatterned polysaccharide surfaces via laser ablation for cell guidance

    Energy Technology Data Exchange (ETDEWEB)

    Barbucci, Rolando; Lamponi, Stefania; Pasqui, Daniela; Rossi, Antonella; Weber, Elisabetta

    2003-03-03

    Micropatterned materials were obtained by a controlled laser ablation of a photoimmobilised homogeneous layer of hyaluronic acid (Hyal) and its sulphated derivative (HyalS). The photoimmobilisation was performed by coating the polysaccharide, adequately functionalised with a photoreactive group, on aminosilanised glass substrate and immobilising it on the surface under UV light. Hyal or HyalS photoimmobilised samples were then subjected to laser ablation with wavelengths in the UV regions in order to drill the pattern. Four different patterns with stripes of 100, 50, 25 and 10 {mu}m were generated. A chemical characterisation by attenuated total reflection/Fourier transform infrared (ATR/FT-IR) and time of flight-secondary ions mass spectrometry (TOF-SIMS) confirmed the success of the laser ablation procedure and the presence of alternating stripes of polysaccharide and native glass. The exact dimensions of the stripes were determined by atomic force microscopy. The analysis of cell behaviour in terms of adhesion, proliferation and movement using mouse fibroblasts (3T3 line) and bovine aortic endothelial cells (BAEC) was also performed.

  12. EXAFS Study of Uranyl Complexation at Pseudomonas fluorescens Cell Surfaces

    Science.gov (United States)

    Bencheikh, R.; Bargar, J. R.; Tebo, B. M.

    2002-12-01

    Little is known about the roles of microbial biomass as a sink and source for uranium in contaminated aquifers, nor of the impact of bacterial biochemistry on uranium speciation in the subsurface. A significant role is implied by the high affinities of both Gram positive and Gram negative cells for binding uranyl (UO2{ 2+}). In the present study, Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy was used to identify membrane functional groups involved in uranyl binding to the Gram negative bacterium Pseudomonas fluorescens from pH 3 to pH 8. Throughout this pH-range, EXAFS spectra can be described primarily in terms of coordination of carboxylic groups to uranyl. U-C distances characteristic of 4-, 5- and 8- membered rings were observed, as well as the possibility of phosphato groups. Both shell-by-shell fits and principle component analyses indicate that the functional groups involved in binding of uranyl to the cell surface do not vary systematically across the pH range investigated. This result contrasts with EXAFS results of uranyl sorbed to Gram positive bacteria, and suggests an important role for long-chain carboxylate-terminated membrane functional groups in binding uranyl.

  13. Cell surface alteration in Epstein-Barr virus-transformed cells from patients with extreme insulin resistance

    International Nuclear Information System (INIS)

    An abnormality was detected in the morphology of the cell surface of Epstein-Barr virus-transformed lymphocytes of patients with genetic forms of insulin resistance. In cells from two patients with leprechaunism and two patients with type A extreme insulin resistance, scanning electron microscopy demonstrated a decrease in the percentage of the cell surface occupied by microvilli in cells from the patients with leprechaunism and type A insulin resistance compared with control cells. When cells from a healthy control subject and one of the patients with leprechaunism (Lep/Ark-1) were incubated with 125I-labeled insulin, there was a decrease in the percentage of 125I-insulin associated with microvilli on the cell surface. Thus, the decreased localization of insulin receptors with the microvillous region of the cell surface was in proportion to the decrease in microvilli

  14. Cell surface alteration in Epstein-Barr virus-transformed cells from patients with extreme insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Gorden, D.L.; Robert, A.; Moncada, V.Y.; Taylor, S.I.; Muehlhauser, J.C.; Carpentier, J.L. (Univ. of Geneva School of Medicine (Switzerland))

    1990-08-01

    An abnormality was detected in the morphology of the cell surface of Epstein-Barr virus-transformed lymphocytes of patients with genetic forms of insulin resistance. In cells from two patients with leprechaunism and two patients with type A extreme insulin resistance, scanning electron microscopy demonstrated a decrease in the percentage of the cell surface occupied by microvilli in cells from the patients with leprechaunism and type A insulin resistance compared with control cells. When cells from a healthy control subject and one of the patients with leprechaunism (Lep/Ark-1) were incubated with {sup 125}I-labeled insulin, there was a decrease in the percentage of {sup 125}I-insulin associated with microvilli on the cell surface. Thus, the decreased localization of insulin receptors with the microvillous region of the cell surface was in proportion to the decrease in microvilli.

  15. MC3T3-E1 Cells on Titanium Surfaces with Nanometer Smoothness and Fibronectin Immobilization

    Directory of Open Access Journals (Sweden)

    Tohru Hayakawa

    2012-01-01

    Full Text Available The present study was aimed to evaluate the viability and total protein contents of osteoblast-like cells on the titanium surface with different surface mechanical treatment, namely, nanometer smoothing (Ra: approximately 2.0 nm and sandblasting (Ra: approximately 1.0 μm, and biochemical treatment, namely, with or without fibronectin immobilization. Fibronectin could be easily immobilized by tresyl chloride-activation technique. MC3T3-E1 cells were seeded on the different titanium surfaces. Cell viability was determined by MTT assay. At 1 day of cell culture, there were no significant differences in cell viability among four different titanium surfaces. At 11 days, sandblasted titanium surface with fibronectin immobilization showed the significantly highest cell viability than other titanium surface. No significant differences existed for total protein contents among four different titanium surfaces at 11 days of cell culture. Scanning electron microscopy observation revealed that smoothness of titanium surface produced more spread cell morphologies, but that fibronectin immobilization did not cause any changes of the morphologies of attached cells. Fibronectin immobilization provided greater amount of the number of attached cells and better arrangement of attached cells. In conclusion, the combination of sandblasting and fibronectin immobilization enhanced the cell viability and fibronectin immobilization providing better arrangements of attached cells.

  16. Exposure to benzene metabolites causes oxidative damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Raj, Abhishek; Nachiappan, Vasanthi

    2016-06-01

    Hydroquinone (HQ) and benzoquinone (BQ) are known benzene metabolites that form reactive intermediates such as reactive oxygen species (ROS). This study attempts to understand the effect of benzene metabolites (HQ and BQ) on the antioxidant status, cell morphology, ROS levels and lipid alterations in the yeast Saccharomyces cerevisiae. There was a reduction in the growth pattern of wild-type cells exposed to HQ/BQ. Exposure of yeast cells to benzene metabolites increased the activity of the anti-oxidant enzymes catalase, superoxide dismutase and glutathione peroxidase but lead to a decrease in ascorbic acid and reduced glutathione. Increased triglyceride level and decreased phospholipid levels were observed with exposure to HQ and BQ. These results suggest that the enzymatic antioxidants were increased and are involved in the protection against macromolecular damage during oxidative stress; presumptively, these enzymes are essential for scavenging the pro-oxidant effects of benzene metabolites. PMID:27016252

  17. High level secretion of cellobiohydrolases by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    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.

  18. Human G protein-coupled receptor studies in Saccharomyces cerevisiae.

    Science.gov (United States)

    Liu, Rongfang; Wong, Winsy; IJzerman, Adriaan P

    2016-08-15

    G protein-coupled receptors (GPCRs) are one of the largest families of membrane proteins, with approximately 800 different GPCRs in the human genome. Signaling via GPCRs regulates many biological processes, such as cell proliferation, differentiation, and development. In addition, many receptors have a pivotal role in immunophysiology. Many hormones and neurotransmitters are ligands for these receptors, and hence it is not surprising that many drugs, either mimicking or blocking the action of the bodily substances, have been developed. It is estimated that 30-40% of current drugs on the market target GPCRs. Further identifying and elucidating the functions of GPCRs will provide opportunities for novel drug discovery, including for immunotherapy. The budding yeast Saccharomyces cerevisiae (S. cerevisiae) is a very important and useful platform in this respect. There are many advantages of using a yeast assay system, as it is cheap, safe and stable; it is also convenient for rapid feasibility and optimization studies. Moreover, it offers a "null" background when studying human GPCRs. New developments regarding human GPCRs expressed in a yeast platform are providing insight into GPCR activation and signaling, and facilitate agonist and antagonist identification. In this review we summarize the latest findings regarding human G-protein-coupled receptors in studies using S. cerevisiae, ever since the year 2005 when we last published a review on this topic. We describe 11 families of GPCRs in detail, while including the principles and developments of each yeast system applied to these different GPCRs and highlight and generalize the experimental findings of GPCR function in these systems. PMID:26920251

  19. Nerve cells culture from lumbar spinal cord on surfaces modified by plasma pyrrole polymerization.

    Science.gov (United States)

    Zuñiga-Aguilar, E; Olayo, R; Ramírez-Fernández, O; Morales, J; Godínez, R

    2014-01-01

    Currently, there are several techniques for modified cell culture surfaces under research to improve cell growth and adhesion. Recently, different methods have been used for surface coating, using biomolecules that enhance cell attachment and growth of nerve cells from spinal cord, such as the use of Poly-DL-Ornithine/Laminin. Plasma-polymerized pyrrole (PPy)-treated surfaces have showed improvement on surfaces biocompatibility with the cells in culture since they do not interfere with any of the biological cell functions. In the present work, we present a novel mouse nerve cell culture technique, using PPy-treated cell culture surfaces. A comparative study of cell survival using Poly-DL-Ornithine/Laminin-treated surfaces was performed. Our results of cell survival when compared with data already reported by other investigators, show that cells cultured on the PPy-modified surface increased survival up to 21 days when compared with Poly-DL-Ornithine/Laminin-coated culture, where 8 days cell survival was obtained. There were electrical and morphological differences in the nerve cells grown in the different surfaces. By comparing the peak ion currents of Poly-DL-Ornithine/Laminin-seeded cells for 8 days with cells grown for 21 days on PPy, an increase of 516% in the Na(+) current and 127% in K(+) currents in cells seeded on PPy were observed. Immunofluorescence techniques showed the presence of cell synapses and culture viability after 21 days. Our results then showed that PPy-modified surfaces are an alternative culture method that increases nerve cells survival from lumbar spinal cord cell culture by preserving its electrical and morphological features. PMID:24650203

  20. Effects of DNP on the cell surface properties of marine bacteria and its implication for adhesion to surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    Jain, A.; Nishad, K.K.; Bhosle, N.B.

    The effect of 2, 4-dinitrophenol (DNP) on extracelluar polysaccharides (EPS), cell surface charge, and hydrophobicity of six marine bacterial cultures was studied, and its influence on attachment of these bacteria to glass and polystyrene...

  1. Cell adhesion on Ti surface with controlled roughness

    Directory of Open Access Journals (Sweden)

    Burgos-Asperilla, Laura

    2015-06-01

    Full Text Available In this report, the in situ interaction between Saos-2 osteoblast cells and a smooth Ti surface was examined over time. The adhesion kinetics and mechanisms of cellular proliferation were monitored by quartz crystal microbalance (QCM and electrochemical impedance spectroscopy (EIS. The rate of Saos-2 attachment on Ti surfaces, obtained from the measurements performed with the QCM, is a first-order reaction, with k=2.10−3 min−1. The impedance measurements indicate that in the absence of cells, the Ti resistance diminishes over time (7 days, due to the presence of amino acids and proteins from the culture medium that have been a dsorbed, while in the presence of osteoblasts, this decrease is much greater because of the compounds generated by the cells that accelerate the dissolution of Ti.En este trabajo, se ha estudiado la interacción in situ entre células osteoblásticas Saos-2 y una superficie de Ti de rugosidad controlada a lo largo del tiempo. El estudio de la cinética y los mecanismos de proliferación celular de adhesión se ha realizado a través de la microbalanza de cristal de cuarzo (QCM y espectroscopía de impedancia electroquímica (EIS. La velocidad de adhesión de los osteoblastos sobre la superficie de Ti obtenida a través de medidas con la QCM, sigue una reacción de primer orden, con k=2×10−3 min−1. Los ensayos de impedancia indican que, en ausencia de las células, la resistencia del Ti disminuye con el tiempo (7 días, debido a la presencia de aminoácidos y proteínas del medio de cultivo que se han adsorbido, mientras que en presencia de células, esta disminución es mucho mayor debido a los productos metabólicos generados por las células que aceleran la disolución del Ti.

  2. Cell Surface Human Airway Trypsin-Like Protease Is Lost During Squamous Cell Carcinogenesis.

    Science.gov (United States)

    Duhaime, Michael J; Page, Khaliph O; Varela, Fausto A; Murray, Andrew S; Silverman, Michael E; Zoratti, Gina L; List, Karin

    2016-07-01

    Cancer progression is accompanied by increased levels of extracellular proteases that are capable of remodeling the extracellular matrix, as well as cleaving and activating growth factors and receptors that are involved in pro-cancerous signaling pathways. Several members of the type II transmembrane serine protease (TTSP) family have been shown to play critical roles in cancer progression, however, the expression or function of the TTSP Human Airway Trypsin-like protease (HAT) in carcinogenesis has not been examined. In the present study we aimed to determine the expression of HAT during squamous cell carcinogenesis. HAT transcript is present in several tissues containing stratified squamous epithelium and decreased expression is observed in carcinomas. We determined that HAT protein is consistently expressed on the cell surface in suprabasal/apical layers of squamous cells in healthy cervical and esophageal epithelia. To assess whether HAT protein is differentially expressed in normal tissue versus tissue in different stages of carcinogenesis, we performed a comprehensive immunohistochemical analysis of HAT protein expression levels and localization in arrays of paraffin embedded human cervical and esophageal carcinomas compared to the corresponding normal tissue. We found that HAT protein is expressed in the non-proliferating, differentiated cellular strata and is lost during the dedifferentiation of epithelial cells, a hallmark of squamous cell carcinogenesis. Thus, HAT expression may potentially be useful as a marker for clinical grading and assessment of patient prognosis in squamous cell carcinomas. J. Cell. Physiol. 231: 1476-1483, 2016. © 2015 Wiley Periodicals, Inc. PMID:26297835

  3. Potential therapeutic target for malignant paragangliomas: ATP synthase on the surface of paraganglioma cells

    Science.gov (United States)

    Fliedner, Stephanie MJ; Yang, Chunzhang; Thompson, Eli; Abu-Asab, Mones; Hsu, Chang-Mei; Lampert, Gary; Eiden, Lee; Tischler, Arthur S; Wesley, Robert; Zhuang, Zhengping; Lehnert, Hendrik; Pacak, Karel

    2015-01-01

    F1FoATP synthase (ATP synthase) is a ubiquitous enzyme complex in eukaryotes. In general it is localized to the mitochondrial inner membrane and serves as the last step in the mitochondrial oxidative phosphorylation of ADP to ATP, utilizing a proton gradient across the inner mitochondrial membrane built by the complexes of the electron transfer chain. However some cell types, including tumors, carry ATP synthase on the cell surface. It was suggested that cell surface ATP synthase helps tumor cells thriving on glycolysis to survive their high acid generation. Angiostatin, aurovertin, resveratrol, and antibodies against the α and β subunits of ATP synthase were shown to bind and selectively inhibit cell surface ATP synthase, promoting tumor cell death. Here we show that ATP synthase β (ATP5B) is present on the cell surface of mouse pheochromocytoma cells as well as tumor cells of human SDHB-derived paragangliomas (PGLs), while being virtually absent on chromaffin primary cells from bovine adrenal medulla by confocal microscopy. The cell surface location of ATP5B was verified in the tissue of an SDHB-derived PGL by immunoelectron microscopy. Treatment of mouse pheochromocytoma cells with resveratrol as well as ATP5B antibody led to statistically significant proliferation inhibition. Our data suggest that PGLs carry ATP synthase on their surface that promotes cell survival or proliferation. Thus, cell surface ATP synthase may present a novel therapeutic target in treating metastatic or inoperable PGLs. PMID:26101719

  4. The topology of plasminogen binding and activation on the surface of human breast cancer cells

    OpenAIRE

    Andronicos, N M; Ranson, M.

    2001-01-01

    The urokinase-dependent activation of plasminogen by breast cancer cells plays an important role in metastasis. We have previously shown that the metastatic breast cancer cell line MDA-MB-231 over-expresses urokinase and binds and efficiently activates plasminogen at the cell surface compared to non-metastatic cells. The aim of this study was to further characterise plasminogen binding and determine the topology of cell surface-bound plasminogen in terms of its potential for activation. The l...

  5. X-ray photoelectron spectroscopy for the study of microbial cell surfaces

    NARCIS (Netherlands)

    van der Mei, Henderina C; de Vries, Jacob; Busscher, Hendrik J

    2000-01-01

    X-ray photoelectron spectroscopy (XPS) is well known for the characterisation of material surfaces, but at first glance, is an unexpected technique to study the composition of microbial cell surfaces. Despite the fact that intimate contact between materials and microbial cell surfaces occurs in many

  6. Surface complexation of neptunium (V) onto whole cells and cell componets of Shewanella alga

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald Timothy [Los Alamos National Laboratory; Deo, Randhir P [ASU; Rittmann, Bruce E [ASU; Songkasiri, Warinthorn [UNAFFILIATED

    2008-01-01

    We systematically quantified surface complexation of neptunium(V) onto whole cells of Shewanella alga strain BrY and onto cell wall and extracellular polymeric substances (EPS) of S. alga. We first performed acid and base titrations and used the mathematical model FITEQL with constant-capacitance surface-complexation to determine the concentrations and deprotonation constants of specific surface functional groups. Deprotonation constants most likely corresponded to a carboxyl site associated with amino acids (pK{sub a} {approx} 2.4), a carboxyl group not associated with amino acids (pK{sub a} {approx} 5), a phosphoryl site (pK{sub a} {approx} 7.2), and an amine site (pK{sub a} > 10). We then carried out batch sorption experiments with Np(V) and each of the S. alga components at different pHs. Results show that solution pH influenced the speciation of Np(V) and each of the surface functional groups. We used the speciation sub-model of the biogeochemical model CCBATCH to compute the stability constants for Np(V) complexation to each surface functional group. The stability constants were similar for each functional group on S. alga bacterial whole cells, cell walls, and EPS, and they explain the complicated sorption patterns when they are combined with the aqueous-phase speciation of Np(V). For pH < 8, NpO{sub 2}{sup +} was the dominant form of Np(V), and its log K values for the low-pK{sub a} carboxyl, other carboxyl, and phosphoryl groups were 1.75, 1.75, and 2.5 to 3.1, respectively. For pH greater than 8, the key surface ligand was amine >XNH3+, which complexed with NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-}. The log K for NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-} complexed onto the amine groups was 3.1 to 3.6. All of the log K values are similar to those of Np(V) complexes with aqueous carboxyl and N-containing carboxyl ligands. These results point towards the important role of surface complexation in defining key actinide-microbiological interactions in the subsurface.

  7. Cell-surface proteoglycan in sea urchin primary mesenchyme cell migration

    Energy Technology Data Exchange (ETDEWEB)

    Lane, M.C.

    1989-01-01

    Early in the development of the sea urchin embryo, the primary mesenchyme cells (PMC) migrate along the basal lamina of the blastocoel. Migration is inhibited in L. pictus embryos cultured in sulfate-free seawater and in S. purpuratus embryos exposed to exogenous {beta}-D-xylosides. An in vitro assay was developed to test the migratory capacity of normal PMC on normal and treated blastocoelic matrix. Sulfate deprivation and exposure to exogenous xyloside render PMC nonmotile on either matrix. Materials removed from the surface of normal PMC by treatment with 1 M urea restored migratory ability to defective cells, whereas a similar preparation isolated from the surface of epithelial cells at the same stage did not. Migration also resumed when cells were removed from the xyloside or returned to normal seawater. The urea extract was partially purified and characterized by radiolabeling, gel electrophoresis, fluorography, ion exchange chromatography, and western blotting. The PMC synthesize a large chondroitin sulfate/dermatan sulfate proteoglycan that is present in an active fraction isolated by chromatography. Chondroitinase ABC digestion of live cells blocked migration reversibly, further supporting the identification of the chondroitin sulfate/dermatan sulfate proteoglycan as the active component in the urea extract. Much of the incorporated sulfate was distributed along the filopodia in {sup 35}SO{sub 4}-labelled PMC by autoradiography. The morphology of normal and treated S. purpuratus PMC was examined by scanning electron microscopy, and differences in spreading, particularly of the extensive filopodia present on the cells, was observed. A model for the role of the chondroitin sulfate/dermatan sulfate proteoglycan in cell detachment during migration is proposed.

  8. Cell-surface proteoglycan in sea urchin primary mesenchyme cell migration

    International Nuclear Information System (INIS)

    Early in the development of the sea urchin embryo, the primary mesenchyme cells (PMC) migrate along the basal lamina of the blastocoel. Migration is inhibited in L. pictus embryos cultured in sulfate-free seawater and in S. purpuratus embryos exposed to exogenous β-D-xylosides. An in vitro assay was developed to test the migratory capacity of normal PMC on normal and treated blastocoelic matrix. Sulfate deprivation and exposure to exogenous xyloside render PMC nonmotile on either matrix. Materials removed from the surface of normal PMC by treatment with 1 M urea restored migratory ability to defective cells, whereas a similar preparation isolated from the surface of epithelial cells at the same stage did not. Migration also resumed when cells were removed from the xyloside or returned to normal seawater. The urea extract was partially purified and characterized by radiolabeling, gel electrophoresis, fluorography, ion exchange chromatography, and western blotting. The PMC synthesize a large chondroitin sulfate/dermatan sulfate proteoglycan that is present in an active fraction isolated by chromatography. Chondroitinase ABC digestion of live cells blocked migration reversibly, further supporting the identification of the chondroitin sulfate/dermatan sulfate proteoglycan as the active component in the urea extract. Much of the incorporated sulfate was distributed along the filopodia in 35SO4-labelled PMC by autoradiography. The morphology of normal and treated S. purpuratus PMC was examined by scanning electron microscopy, and differences in spreading, particularly of the extensive filopodia present on the cells, was observed. A model for the role of the chondroitin sulfate/dermatan sulfate proteoglycan in cell detachment during migration is proposed

  9. Cell surface molecules and fibronectin-mediated cell adhesion: effect of proteolytic digestion of membrane proteins

    OpenAIRE

    1982-01-01

    Proteases have been used as a tool to investigate the role of surface molecules in fibronectin-mediated cell adhesion. Proteolytic digestion of membrane-proteins by pronase (1 mg/ml for 20 min at 37 degrees C) completely inhibited adhesion of baby hamster kidney (BHK) fibroblasts on fibronectin-coated plastic dishes. Various degrees of inhibition were also obtained after treatment with proteinase K, chymotrypsin, papain, subtilopeptidase A, and thermolysin. Protein synthesis was required to r...

  10. Cell surface estrogen receptor alpha is upregulated during subchronic metabolic stress and inhibits neuronal cell degeneration.

    Directory of Open Access Journals (Sweden)

    Cristiana Barbati

    Full Text Available In addition to the classical nuclear estrogen receptor, the expression of non-nuclear estrogen receptors localized to the cell surface membrane (mER has recently been demonstrated. Estrogen and its receptors have been implicated in the development or progression of numerous neurodegenerative disorders. Furthermore, the pathogenesis of these diseases has been associated with disturbances of two key cellular programs: apoptosis and autophagy. An excess of apoptosis or a defect in autophagy has been implicated in neurodegeneration. The aim of this study was to clarify the role of ER in determining neuronal cell fate and the possible implication of these receptors in regulating either apoptosis or autophagy. The human neuronal cell line SH-SY5Y and mouse neuronal cells in primary culture were thus exposed to chronic minimal peroxide treatment (CMP, a form of subcytotoxic minimal chronic stress previously that mimics multiple aspects of long-term cell stress and represents a limited molecular proxy for neurodegenerative processes. We actually found that either E2 or E2-bovine serum albumin construct (E2BSA, i.e. a non-permeant form of E2 was capable of modulating intracellular cell signals and regulating cell survival and death. In particular, under CMP, the up-regulation of mERα, but not mERβ, was associated with functional signals (ERK phosphorylation and p38 dephosphorylation compatible with autophagic cytoprotection triggering and leading to cell survival. The mERα trafficking appeared to be independent of the microfilament system cytoskeletal network but was seemingly associated with microtubular apparatus network, i.e., to MAP2 molecular chaperone. Importantly, antioxidant treatments, administration of siRNA to ERα, or the presence of antagonist of ERα hindered these events. These results support that the surface expression of mERα plays a pivotal role in determining cell fate, and that ligand-induced activation of mER signalling exerts a

  11. The effect of cerium valence states at cerium oxide nanoparticle surfaces on cell proliferation

    KAUST Repository

    Naganuma, Tamaki

    2014-05-01

    Understanding and controlling cell proliferation on biomaterial surfaces is critical for scaffold/artificial-niche design in tissue engineering. The mechanism by which underlying integrin ligates with functionalized biomaterials to induce cell proliferation is still not completely understood. In this study, poly-l-lactide (PL) scaffold surfaces were functionalized using layers of cerium oxide nanoparticles (CNPs), which have recently attracted attention for use in therapeutic application due to their catalytic ability of Ce4+ and Ce3+ sites. To isolate the influence of Ce valance states of CNPs on cell proliferation, human mesenchymal stem cells (hMSCs) and osteoblast-like cells (MG63) were cultured on the PL/CNP surfaces with dominant Ce4+ and Ce3+ regions. Despite cell type (hMSCs and MG63 cells), different surface features of Ce4+ and Ce3+ regions clearly promoted and inhibited cell spreading, migration and adhesion behavior, resulting in rapid and slow cell proliferation, respectively. Cell proliferation results of various modified CNPs with different surface charge and hydrophobicity/hydrophilicity, indicate that Ce valence states closely correlated with the specific cell morphologies and cell-material interactions that trigger cell proliferation. This finding suggests that the cell-material interactions, which influence cell proliferation, may be controlled by introduction of metal elements with different valence states onto the biomaterial surface. © 2014 Elsevier Ltd.

  12. Increasing binding density of yeast cells by control of surface charge with allylamine grafting to ion modified polymer surfaces.

    Science.gov (United States)

    Tran, Clara T H; Kondyurin, Alexey; Chrzanowski, Wojciech; Bilek, Marcela M M; McKenzie, David R

    2014-10-01

    Plasma immersion ion implantation (PIII) treatment of polymers creates a biointerface capable of direct covalent immobilization of biomolecules. The immobilization of protein molecules is achieved by covalent bonds formed between embedded radicals on the treated surface and amino acid side chains and cells can be immobilized through cell-wall proteins. The attachment density of negatively charged entities on a PIII treated surface is inhibited by its negative surface charge at neutral pH. To reduce the negative charge of PIII treated surfaces in phosphate buffer (pH 7.4, 11mM), we develop an effective approach of grafting allylamine monomers onto the treated surface. The results reveal reactions between allylamine and radicals on the PIII treated surface. One of these triggers polymerization, increasing the number of amine groups grafted. As a consequence, the PIII treated polystyrene surface after allylamine exposure becomes more hydrophobic and less negatively charged in phosphate buffer. Using yeast cells as an example, we have shown a significant improvement (6-15 times) of cell density immobilized on the PIII treated surface after exposure to allylamine. PMID:25092587

  13. Distribution, Arrangement and Interconnectedness of Cell Surface Receptor sites in the body of an Organism

    Directory of Open Access Journals (Sweden)

    Utoh-Nedosa

    2011-01-01

    Full Text Available Cell surface receptors have been identified as the sites of disease infectivity in living organisms in a previous study. Drugs used for the treatment or cure of infections have to eliminate infections through attacking infective organisms at the cell surface receptors to which the infective organisms are attached. Problem statement: The present study examines a wide sample of living things to get more information on the relationship of one cell surface receptor to other cell surface receptors in the body of an organism. Approach: The arrangement of cell surface receptors on the external covering of a few samples of fruits, leaves, stems, dry wood of a plant; wall gecko and some parts of the human body, were examined and photographed. Transverse and/or Longitudinal sections of soursop fruit and sycamore fruit were also examined and photographed. The five different coverings of the fleshy part of a coconut were also photographed. The photographs were studied to note the relationship of disease infection attached to cell surface receptors on the external surface of an organ to disease infection on the innermost covering of the same organ. Results: The results of the study showed that all living things had ubiquitous distribution of cell surface receptors which are usually observable with the unaided eye as dots or spots on the external covering of an organ, tissue or cell. The dots or receptor sites of cell surface receptors in the study are arranged in lines which were perpendicular, oblique, transverse or arranged in any other lineal geometrical form. The lineally arranged cell surface receptors were noted to be connected by grooves, channels or pipes which joined other receptor channels or intersected with them. Smaller cell surface receptor channels emptied into bigger channels or continued as small sized channels that ran side by side in a connective tissue bundle. These connective tissue bundles that carried many independent small-sized cell

  14. Evaluation of osteogenic cell culture and osteogenic/peripheral blood mononuclear human cell co-culture on modified titanium surfaces

    International Nuclear Information System (INIS)

    This study aimed to determine the effect of a bioactive ceramic coating on titanium in the nanothickness range on human osteogenic cells, peripheral blood mononuclear cells (PBMC) and on osteogenic cells co-cultured with PBMC without exogenous stimuli. Cell viability, proliferation, adhesion, cytokine release (IL1β, TGFβ1, IL10 and IL17) and intracellular stain for osteopontin and alkaline phosphatase were assessed. Morphologic evaluation showed smaller and less spread cell aspects in co-culture relative to osteogenic cell culture. Cell viability, proliferation and adhesion kinetics were differently influenced by surface texture/chemistry in culture versus co-culture. Cytokine release was also influenced by the interaction between mononuclear and osteogenic cells (mediators released by mononuclear cells acted on osteogenic cells and vice versa). In general, ‘multi-cell type’ interactions played a more remarkable role than the surface roughness or chemistry utilized on the in vitro cellular events related to initial stages of bone formation. (paper)

  15. Surface grafting of carboxylic groups onto thermoplastic polyurethanes to reduce cell adhesion

    International Nuclear Information System (INIS)

    The interaction of polymers with other materials is an important issue, being their surface properties clearly crucial. For some important polymer applications, their surfaces have to be modified. Surface modification aims to tailor the surface characteristics of a material for a specific application without affecting its bulk properties. Materials can be surface modified by using biological, chemical or physical methods. The aim of this work was to improve the reactivity of the thermoplastic polyurethane (TPU) material (Elastollan®) surface and to make its surface cell repellent by grafting carboxylic groups onto its surface. Two TPU materials were studied: a polyether-based TPU and a polyester-based TPU. The grafting efficiency was evaluated by contact angle measurements and by analytical determination of the COOH groups. Scanning electron microscopy (SEM) of the membranes surface was performed as well as cell adhesion tests. It was proved that the surfaces of the TPUs membranes were successfully modified and that cell adhesion was remarkably reduced.

  16. Heparanase facilitates cell adhesion and spreading by clustering of cell surface heparan sulfate proteoglycans.

    Directory of Open Access Journals (Sweden)

    Flonia Levy-Adam

    Full Text Available Heparanase is a heparan sulfate (HS degrading endoglycosidase participating in extracellular matrix degradation and remodeling. Apart of its well characterized enzymatic activity, heparanase was noted to exert also enzymatic-independent functions. Non-enzymatic activities of heparanase include enhanced adhesion of tumor-derived cells and primary T-cells. Attempting to identify functional domains of heparanase that would serve as targets for drug development, we have identified heparin binding domains of heparanase. A corresponding peptide (residues Lys(158-Asp(171, termed KKDC was demonstrated to physically associate with heparin and HS, and to inhibit heparanase enzymatic activity. We hypothesized that the pro-adhesive properties of heparanase are mediated by its interaction with cell surface HS proteoglycans, and utilized the KKDC peptide to examine this possibility. We provide evidence that the KKDC peptide interacts with cell membrane HS, resulting in clustering of syndecan-1 and syndecan-4. We applied classical analysis of cell morphology, fluorescent and time-lapse microscopy and demonstrated that the KKDC peptide efficiently stimulates the adhesion and spreading of various cell types, mediated by PKC, Src, and the small GTPase Rac1. These results support, and further substantiate the notion that heparanase function is not limited to its enzymatic activity.

  17. Surface free energy predominates in cell adhesion to hydroxyapatite through wettability.

    Science.gov (United States)

    Nakamura, Miho; Hori, Naoko; Ando, Hiroshi; Namba, Saki; Toyama, Takeshi; Nishimiya, Nobuyuki; Yamashita, Kimihiro

    2016-05-01

    The initial adhesion of cells to biomaterials is critical in the regulation of subsequent cell behaviors. The purpose of this study was to investigate a mechanism through which the surface wettability of biomaterials can be improved and determine the effects of biomaterial surface characteristics on cellular behaviors. We investigated the surface characteristics of various types of hydroxyapatite after sintering in different atmospheres and examined the effects of various surface characteristics on cell adhesion to study cell-biomaterial interactions. Sintering atmosphere affects the polarization capacity of hydroxyapatite by changing hydroxide ion content and grain size. Compared with hydroxyapatite sintered in air, hydroxyapatite sintered in saturated water vapor had a higher polarization capacity that increased surface free energy and improved wettability, which in turn accelerated cell adhesion. We determined the optimal conditions of hydroxyapatite polarization for the improvement of surface wettability and acceleration of cell adhesion. PMID:26952425

  18. 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...

  19. Tangential Ultrafiltration of Aqueous "Saccharomyces Cerevisiae" Suspensions

    Science.gov (United States)

    Silva, Carlos M.; Neves, Patricia S.; Da Silva, Francisco A.; Xavier, Ana M. R. B.; Eusebio, M. F. J.

    2008-01-01

    Experimental work on ultrafiltration is presented to illustrate the practical and theoretical principles of this separation technique. The laboratory exercise comprises experiments with pure water and with aqueous "Saccharomyces cerevisiae" (from commercial Baker's yeast) suspensions. With this work students detect the characteristic phenomena…

  20. Functional Expression and Characterization of Schizosaccharomyces pombe Avt3p as a Vacuolar Amino Acid Exporter in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Soracom Chardwiriyapreecha

    Full Text Available In Saccharomyces cerevisiae, Avt3p and Avt4p mediate the extrusion of several amino acids from the vacuolar lumen into the cytosol. SpAvt3p of Schizosaccharomyces pombe, a homologue of these vacuolar amino acid transporters, has been indicated to be involved in spore formation. In this study, we confirmed that GFP-SpAvt3p localized to the vacuolar membrane in S. pombe. The amounts of various amino acids increased significantly in the vacuolar pool of avt3Δ cells, but decreased in that of avt3+-overexpressing avt3Δ cells. These results suggest that SpAvt3p participates in the vacuolar compartmentalization of amino acids in S. pombe. To examine the export activity of SpAvt3p, we expressed the avt3+ gene in S. cerevisiae cells. We found that the heterologously overproduced GFP-SpAvt3p localized to the vacuolar membrane in S. cerevisiae. Using the vacuolar membrane vesicles isolated from avt3+-overexpressing S. cerevisiae cells, we detected the export activities of alanine and tyrosine in an ATP-dependent manner. These activities were inhibited by the addition of a V-ATPase inhibitor, concanamycin A, thereby suggesting that the activity of SpAvt3p is dependent on a proton electrochemical gradient generated by the action of V-ATPase. In addition, the amounts of various amino acids in the vacuolar pools of S. cerevisiae cells were decreased by the overproduction of SpAvt3p, which indicated that SpAvt3p was functional in S. cerevisiae cells. Thus, SpAvt3p is a vacuolar transporter that is involved in the export of amino acids from S. pombe vacuoles.