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Sample records for alkaline sucrose gradients

  1. Size-separation of silver nanoparticles using sucrose gradient centrifugation

    SciTech Connect

    Suresh, Anil K.; Pelletier, Dale A.; Moon, Ji Won; Phelps, Tommy; Doktycz, Mitchel John

    2015-08-28

    Size and shape distributions of nanoparticles can drastically contribute to the overall properties of nanoparticles, thereby influencing their interaction with different chemotherapeutic molecules, biological organisms and or materials and cell types. Therefore, to exploit the proper use of nanoparticles for various biomedical and biosensor applications, it is important to obtain well-separated monodispersed nanoparticles. However, gaining precise control over the morphological characteristics of nanoparticles during their synthesis is often a challenging task. Consequently, post-synthesis separation of nanoparticles is necessary. In the present study, we demonstrate the successful one-pot post-synthesis separation of anisotropic silver nanoparticles to near modispersities using sucrose density gradient sedimentation. The separation of the nanoparticles was evidenced based on optical confirmation, and spectrophotometric and transmission electron microscopy measurements. Our results clearly demonstrate the facile separation of anisotropic silver nanoparticles using sucrose density gradient sedimentation and can enable the use of nanoparticles for various biomedical applications.

  2. Polysome analysis and RNA purification from sucrose gradients.

    PubMed

    Mašek, Tomáš; Valášek, Leoš; Pospíšek, Martin

    2011-01-01

    Velocity separation of translation complexes in linear sucrose gradients is the ultimate method for both analysis of the overall fitness of protein synthesis as well as for detailed investigation of physiological roles played by individual factors of the translational machinery. Polysome profile analysis is a frequently performed task in translational control research that not only enables direct monitoring of the efficiency of translation but can easily be extended with a wide range of downstream applications such as Northern and Western blotting, genome-wide microarray analysis or qRT-PCR. This chapter provides a basic overview of the polysome profile analysis technique and the RNA isolation procedure from sucrose gradients. We also discuss possible experimental pitfalls of data normalization, describe main alternatives of the basic protocol and outline a novel application of denaturing RNA electrophoresis in several steps of polysome profile analysis.

  3. Size-separation of silver nanoparticles using sucrose gradient centrifugation

    DOE PAGES

    Suresh, Anil K.; Pelletier, Dale A.; Moon, Ji Won; Phelps, Tommy; Doktycz, Mitchel John

    2015-08-28

    Size and shape distributions of nanoparticles can drastically contribute to the overall properties of nanoparticles, thereby influencing their interaction with different chemotherapeutic molecules, biological organisms and or materials and cell types. Therefore, to exploit the proper use of nanoparticles for various biomedical and biosensor applications, it is important to obtain well-separated monodispersed nanoparticles. However, gaining precise control over the morphological characteristics of nanoparticles during their synthesis is often a challenging task. Consequently, post-synthesis separation of nanoparticles is necessary. In the present study, we demonstrate the successful one-pot post-synthesis separation of anisotropic silver nanoparticles to near modispersities using sucrose density gradientmore » sedimentation. The separation of the nanoparticles was evidenced based on optical confirmation, and spectrophotometric and transmission electron microscopy measurements. Our results clearly demonstrate the facile separation of anisotropic silver nanoparticles using sucrose density gradient sedimentation and can enable the use of nanoparticles for various biomedical applications.« less

  4. Interpretation of sucrose gradient sedimentation pattern of deoxyribonucleic acid fragments resulting from random breaks.

    PubMed

    Litwin, S; Shahn, E; Kozinski, A W

    1969-07-01

    Mass distribution in a sucrose gradient of deoxyribonucleic acid (DNA) fragments arising as a result of random breaks is predicted by analytical means from which computer evaluations are plotted. The analytical results are compared with the results of verifying experiments: (i) a Monte Carlo computer experiment in which simulated molecules of DNA were individuals of unit length subjected to random "breaks" applied by a random number generator, and (ii) an in vitro experiment in which molecules of T4 DNA, highly labeled with (32)P, were stored in liquid nitrogen for variable periods of time during which a precisely known number of (32)P atoms decayed, causing single-stranded breaks. The distribution of sizes of the resulting fragments was measured in an alkaline sucrose gradient. The profiles obtained in this fashion were compared with the mathematical predictions. Both experiments agree with the analytical approach and thus permit the use of the graphs obtained from the latter as a means of determining the average number of random breaks in DNA from distributions obtained experimentally in a sucrose gradient. An example of the application of this procedure to a previously unresolved problem is provided in the case of DNA from ultraviolet-irradiated phage which undergoes a dose-dependent intracellular breakdown. The relationship between the number of lethal hits and the number of single-stranded breaks was not previously established. A comparison of the calculated number of nicks per strand of DNA with the known dose in phage-lethal hits reveals a relationship closely approximating one lethal hit to one single-stranded break. PMID:5804949

  5. Palladium nanoparticles synthesized by reducing species generated during a successive acidic/alkaline treatment of sucrose

    NASA Astrophysics Data System (ADS)

    Amornkitbamrung, Lunjakorn; Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Ekgasit, Sanong

    2014-03-01

    Uniform spherical palladium nanoparticles with an average particle size of 4.3 ± 0.5 nm were successfully synthesized by reducing H2PdCl4 with intermediates in situ generated during a successive acidic/alkaline treatment of sucrose. A successive acidic/alkaline treatment plays an important role on converting the non-reducing sucrose into efficient reducing species containing aldehyde functionality. The Benedict's test corroborates the development and vanishing of the in situ generated reducing species upon prolonged degradation. An increase in alkalinity drastically improves the reduction efficiency. ATR FT-IR spectroscopy indicated spontaneous development of carboxylate after the alkaline treatment. Under the employed condition, small organic species with carbonyl groups (aldehyde, acid, and acid salt) were generated through the sucrose degradation before being oxidized to carbonate after an hour of the treatment. Sucrose was completely decomposed into carbonate after a 24-h successive acidic/alkaline treatment. The synthesized palladium nanoparticles express a good catalytic activity in the decolorization process of Congo red by sodium borohydride.

  6. Palladium nanoparticles synthesized by reducing species generated during a successive acidic/alkaline treatment of sucrose.

    PubMed

    Amornkitbamrung, Lunjakorn; Pienpinijtham, Prompong; Thammacharoen, Chuchaat; Ekgasit, Sanong

    2014-03-25

    Uniform spherical palladium nanoparticles with an average particle size of 4.3±0.5 nm were successfully synthesized by reducing H2PdCl4 with intermediates in situ generated during a successive acidic/alkaline treatment of sucrose. A successive acidic/alkaline treatment plays an important role on converting the non-reducing sucrose into efficient reducing species containing aldehyde functionality. The Benedict's test corroborates the development and vanishing of the in situ generated reducing species upon prolonged degradation. An increase in alkalinity drastically improves the reduction efficiency. ATR FT-IR spectroscopy indicated spontaneous development of carboxylate after the alkaline treatment. Under the employed condition, small organic species with carbonyl groups (aldehyde, acid, and acid salt) were generated through the sucrose degradation before being oxidized to carbonate after an hour of the treatment. Sucrose was completely decomposed into carbonate after a 24-h successive acidic/alkaline treatment. The synthesized palladium nanoparticles express a good catalytic activity in the decolorization process of Congo red by sodium borohydride. PMID:24309181

  7. Analysis of Protein Oligomeric Species by Sucrose Gradients.

    PubMed

    Tenreiro, Sandra; Macedo, Diana; Marijanovic, Zrinka; Outeiro, Tiago Fleming

    2016-01-01

    Protein misfolding, aggregation, and accumulation are a common hallmark in various neurodegenerative diseases. Invariably, the process of protein aggregation is associated with both a loss of the normal biological function of the protein and a gain of toxic function that ultimately leads to cell death. The precise origin of protein cytotoxicity is presently unclear but the predominant theory posits that smaller oligomeric species are more toxic than larger aggregated forms. While there is still no consensus on this subject, this is a central question that needs to be addressed in order to enable the design of novel and more effective therapeutic strategies. Accordingly, the development and utilization of approaches that allow the biochemical characterization of the formed oligomeric species in a given cellular or animal model will enable the correlation with cytotoxicity and other parameters of interest.Here, we provide a detailed description of a low-cost protocol for the analysis of protein oligomeric species from both yeast and mammalian cell lines models, based on their separation according to sedimentation velocity using high-speed centrifugation in sucrose gradients. This approach is an adaptation of existing protocols that enabled us to overcome existing technical issues and obtain reliable results that are instrumental for the characterization of the types of protein aggregates formed by different proteins of interest in the context of neurodegenerative disorders. PMID:27613047

  8. The construction and analysis of sucrose gradients for use with zonal rotors.

    PubMed Central

    Hirst, W; Cox, R A

    1976-01-01

    The rate of sedimentation of a particle in a sucrose solution depends on the viscosity and density of the medium. These two variables are related to the sucrose concentration and the temperature of the medium by new simple equations. These equations were used in a rapid iterative procedure that relates the distance moved by a zone in a continuous sucrose gradient to its sedimentation coefficient. It is shown by comparison with experiment that this iterative method allows the distance moved by a zone to be calculated rapidly. The method may therefore be used to optimize the separation of particles in a sucrose-gradient-centrifugation experiment. The method also allows the unknown sedimentation coefficients of several zones to be measured from a single sucrose-gradient-centrifugation experiment. PMID:793582

  9. Characterization of a novel low-temperature-active, alkaline and sucrose-tolerant invertase

    PubMed Central

    Zhou, Junpei; He, Limei; Gao, Yajie; Han, Nanyu; Zhang, Rui; Wu, Qian; Li, Junjun; Tang, Xianghua; Xu, Bo; Ding, Junmei; Huang, Zunxi

    2016-01-01

    A glycoside hydrolase family 32 invertase from Bacillus sp. HJ14 was expressed in Escherichia coli. The purified recombinant enzyme (rInvHJ14) showed typical biochemical properties of low-temperature-active and alkaline enzymes: (i) rInvHJ14 was active and stable in the range of pH 7.0–9.5 with an apparent pH optimum of 8.0; (ii) rInvHJ14 was most active but not stable at 30–32.5 °C, with 19.7, 48.2 and 82.1% of its maximum activity when assayed at 0, 10 and 20 °C, respectively, and the Ea, ΔG* (30 °C), Km (30 °C) and kcat (30 °C) values for hydrolysis of sucrose by rInvHJ14 was 47.6 kJ mol−1, 57.6 kJ mol−1, 62.9 mM and 746.2 s−1, respectively. The enzyme also showed strong sucrose tolerance. rInvHJ14 preserved approximately 50% of its highest activity in the presence of 2045.0 mM sucrose. Furthermore, potential factors for low-temperature-active and alkaline adaptations of rInvHJ14 were presumed. Compared with more thermostable homologs, rInvHJ14 has a higher frequency of glycine residues and a longer loop but a lower frequency of proline residues (especially in a loop) in the catalytic domain. The catalytic pockets of acid invertases were almost negatively charged while that of alkaline rInvHJ14 was mostly positively charged. PMID:27553125

  10. Characterization of a novel low-temperature-active, alkaline and sucrose-tolerant invertase.

    PubMed

    Zhou, Junpei; He, Limei; Gao, Yajie; Han, Nanyu; Zhang, Rui; Wu, Qian; Li, Junjun; Tang, Xianghua; Xu, Bo; Ding, Junmei; Huang, Zunxi

    2016-01-01

    A glycoside hydrolase family 32 invertase from Bacillus sp. HJ14 was expressed in Escherichia coli. The purified recombinant enzyme (rInvHJ14) showed typical biochemical properties of low-temperature-active and alkaline enzymes: (i) rInvHJ14 was active and stable in the range of pH 7.0-9.5 with an apparent pH optimum of 8.0; (ii) rInvHJ14 was most active but not stable at 30-32.5 °C, with 19.7, 48.2 and 82.1% of its maximum activity when assayed at 0, 10 and 20 °C, respectively, and the Ea, ΔG(*) (30 °C), Km (30 °C) and kcat (30 °C) values for hydrolysis of sucrose by rInvHJ14 was 47.6 kJ mol(-1), 57.6 kJ mol(-1), 62.9 mM and 746.2 s(-1), respectively. The enzyme also showed strong sucrose tolerance. rInvHJ14 preserved approximately 50% of its highest activity in the presence of 2045.0 mM sucrose. Furthermore, potential factors for low-temperature-active and alkaline adaptations of rInvHJ14 were presumed. Compared with more thermostable homologs, rInvHJ14 has a higher frequency of glycine residues and a longer loop but a lower frequency of proline residues (especially in a loop) in the catalytic domain. The catalytic pockets of acid invertases were almost negatively charged while that of alkaline rInvHJ14 was mostly positively charged. PMID:27553125

  11. Examination of the Qβ-Replicase Reaction by Sucrose Gradient and Gel Electrophoresis

    PubMed Central

    Pace, N. R.; Bishop, D. H. L.; Spiegelman, S.

    1967-01-01

    The products of an in vitro synthesis with the Qβ replicase purified from Escherichia coli infected by the ribonucleic acid (RNA) bacteriophage Qβ were examined by sucrose gradient centrifugation and polyacrylamide gel electrophoresis. It was found that, in contrast to sucrose gradients, gel electrophoresis clearly resolved four classes in the newly synthesized RNA. The product was found to contain mature Qβ-RNA and small-molecular-weight RNA. In addition, two species were identified which corresponded to the structures found in vivo by Francke and Hofschneider and by Franklin. All of the participants implicated in RNA replication by in vivo studies have now been synthesized in vitro and isolated from the reaction mixture. PMID:4912234

  12. Microvilli of the human term placenta. Isolation and subfractionation by centrifugation in sucrose density gradients.

    PubMed Central

    Truman, P; Wakefield, J S; Ford, H C

    1981-01-01

    Human placental microvilli were isolated and separated into two fractions by centrifugation in sucrose density gradients. Electron-microscopic morphology and morphometry, the distribution of enzymic activities and the results of sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of proteins were used to assess the purity of the final preparations and to define their properties. The combined evidence strongly suggested that the preparations contained negligible material that was not plasma membrane. The two fractions of microvilli differed in buoyant density, protein composition, enzyme specific activities and microscopic appearance. Some of these differences were explained by the absence of internal structure in the microvilli of the lighter fraction. Images PLATE 1 PLATE 2 PLATE 3 PMID:7306066

  13. Sucrose gradient analysis: computer simulation and measurement of the parameters involved in the sedimentation of DNA molecules.

    PubMed

    Macchiato, M F; Grossi, G F; Gialanella, G C

    1977-01-01

    The Montecarlo method is used to computer simulate a random distribution of molecular lengths generated by inducing T4 DNA fragmentation through the decay of 32P atoms introduced in the molecule. Taking into account the experimental conditions we find that the value of alpha for alkali sucrose gradients is 0.46 +/- 0.02 and does not depend on the running time. Our findings also prove that the computer simulation can be utilized to analyze sedimentation profiles of DNA molecules fragmented in vivo. PMID:143820

  14. An Experiment Using Sucrose Density Gradients in the Undergraduate Biochemistry Laboratory.

    ERIC Educational Resources Information Center

    Turchi, Sandra L.; Weiss, Monica

    1988-01-01

    Describes an experiment to be performed in an undergraduate biochemistry laboratory that is based on a gradient centrifugation system employing a simple bench top centrifuge, a freezer, and frozen surcose gradient solution to separate macromolecules and subcellular components. (CW)

  15. From Geochemistry to Biochemistry: Simulating Prebiotic Chemistry Driven by Geochemical Gradients in Alkaline Hydrothermal Vents

    NASA Astrophysics Data System (ADS)

    Barge, Laurie

    2016-07-01

    Planetary water-rock interfaces generate energy in the form of redox, pH, and thermal gradients, and these disequilibria are particularly focused in hydrothermal vent systems where the reducing, heated hydrothermal fluid feeds back into the more oxidizing ocean. Alkaline hydrothermal vents have been proposed as a likely location for the origin of life on the early Earth due to various factors: including the hydrothermal pH / Eh gradients that resemble the ubiquitous electrical / proton gradients in biology, the catalytic hydrothermal precipitates that resemble inorganic catalysts in enzymes, and the presence of electron donors and acceptors in hydrothermal systems (e.g. H2 + CH4 and CO2) that are thought to have been utilized in the earliest metabolisms. Of particular importance for the emergence of metabolism are the mineral "chimneys" that precipitate at the vent fluid / seawater interface. Hydrothermal chimneys are flow-through chemical reactors that form porous and permeable inorganic membranes transecting geochemical gradients; in some ways similar to biological membranes that transect proton / ion gradients and harness these disequilibria to drive metabolism. These emergent chimney structures in the far-from-equilibrium system of the alkaline vent have many properties of interest to the origin of life that can be simulated in the laboratory: for example, they can generate electrical energy and drive redox reactions, and produce catalytic minerals (in particular the metal sulfides and iron oxyhydroxides - "green rust") that can facilitate chemical reactions towards proto-metabolic cycles and biosynthesis. Many of the factors prompting interest in alkaline hydrothermal vents on Earth may also have been present on early Mars, or even presently within icy worlds such as Europa or Enceladus - thus, understanding the disequilibria and resulting prebiotic chemistry in these systems can be of great use in assessing the potential for other environments in the Solar

  16. HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

    PubMed

    Liu, Shujin; Lan, Jixian; Zhou, Binhui; Qin, Yunxia; Zhou, Yihua; Xiao, Xiaohu; Yang, Jianghua; Gou, Jiqing; Qi, Jiyan; Huang, Yacheng; Tang, Chaorong

    2015-04-01

    In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular.

  17. HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

    PubMed

    Liu, Shujin; Lan, Jixian; Zhou, Binhui; Qin, Yunxia; Zhou, Yihua; Xiao, Xiaohu; Yang, Jianghua; Gou, Jiqing; Qi, Jiyan; Huang, Yacheng; Tang, Chaorong

    2015-04-01

    In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular. PMID:25581169

  18. Bacterial community responses to a gradient of alkaline mountaintop mine drainage in Central Appalachian streams.

    PubMed

    Bier, Raven L; Voss, Kristofor A; Bernhardt, Emily S

    2015-06-01

    Microbial community composition and diversity change along chemical gradients, leading to the expectation that microbial community information might provide new gradient characterizations. Here we examine stream bacteria composition and diversity along a strong chemical gradient in Central Appalachian streams. Coal mining in the region generates alkaline mine drainage (AlkMD), causing dramatic increases in conductivity, alkalinity, sulfate and metals sufficient to degrade stream macrobiota communities throughout the ecoregion. In this study, we examined the relationship between water and biofilm chemistry and biofilm bacteria taxonomic composition in streams where active and reclaimed surface coal mines occupied 0-96% of watershed surface area. We incubated wood veneers in each stream site for 4 months to develop biofilms on similar substrates. We sampled water chemistry at the time of deployment and collection, and after 1 month. Following incubation, we collected biofilms for microbial and chemical characterization. Microbial composition was determined by pyrosequencing 16S rRNA amplicons. Biofilm subsamples were analyzed by inductively coupled plasma mass spectrometry to determine metal concentrations. Our results show that microbial community composition differed significantly between AlkMD-exposed and AlkMD-unexposed sites, and that compositional dissimilarity increased with AlkMD loading. Diversity was not correlated with pH or extent of upstream mining, but instead correlated with biofilm concentrations of Cd, Mn, Zn and Ni. Within mined sites, the extent of upstream mining was negatively correlated with taxonomic richness. Despite major compositional shifts, functional capacity predicted with PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) correlated with mining in only 3 of 43 level-2 KEGG (Kyoto Encyclopedia of Genes and Genomes) Orthology groups.

  19. Bacterial community responses to a gradient of alkaline mountaintop mine drainage in Central Appalachian streams

    PubMed Central

    Bier, Raven L; Voss, Kristofor A; Bernhardt, Emily S

    2015-01-01

    Microbial community composition and diversity change along chemical gradients, leading to the expectation that microbial community information might provide new gradient characterizations. Here we examine stream bacteria composition and diversity along a strong chemical gradient in Central Appalachian streams. Coal mining in the region generates alkaline mine drainage (AlkMD), causing dramatic increases in conductivity, alkalinity, sulfate and metals sufficient to degrade stream macrobiota communities throughout the ecoregion. In this study, we examined the relationship between water and biofilm chemistry and biofilm bacteria taxonomic composition in streams where active and reclaimed surface coal mines occupied 0–96% of watershed surface area. We incubated wood veneers in each stream site for 4 months to develop biofilms on similar substrates. We sampled water chemistry at the time of deployment and collection, and after 1 month. Following incubation, we collected biofilms for microbial and chemical characterization. Microbial composition was determined by pyrosequencing 16S rRNA amplicons. Biofilm subsamples were analyzed by inductively coupled plasma mass spectrometry to determine metal concentrations. Our results show that microbial community composition differed significantly between AlkMD-exposed and AlkMD-unexposed sites, and that compositional dissimilarity increased with AlkMD loading. Diversity was not correlated with pH or extent of upstream mining, but instead correlated with biofilm concentrations of Cd, Mn, Zn and Ni. Within mined sites, the extent of upstream mining was negatively correlated with taxonomic richness. Despite major compositional shifts, functional capacity predicted with PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) correlated with mining in only 3 of 43 level-2 KEGG (Kyoto Encyclopedia of Genes and Genomes) Orthology groups. PMID:25500511

  20. Sucrose density gradient centrifugation and cross-flow filtration methods for the production of arbovirus antigens inactivated by binary ethylenimine

    PubMed Central

    Pyke, Alyssa T; Phillips, Debra A; Chuan, Teck F; Smith, Greg A

    2004-01-01

    Background Sucrose density gradient centrifugation and cross-flow filtration methods have been developed and standardised for the safe and reproducible production of inactivated arbovirus antigens which are appropriate for use in diagnostic serological applications. Methods To optimise the maximum titre of growth during the propagation of arboviruses, the multiplicity of infection and choice of cell line were investigated using stocks of Ross River virus and Barmah Forest virus grown in both mosquito and mammalian cell lines. To standardise and improve the efficacy of the inactivation of arboviral suspensions, stocks of Ross River virus, Barmah Forest virus, Japanese encephalitis virus, Murray Valley encephalitis virus and Alfuy virus were chemically inactivated using binary ethylenimine at a final concentration of 3 mM. Aliquots were then taken at hourly intervals and crude inactivation rates were determined for each virus using a plaque assay. To ensure complete inactivation, the same aliquots were each passaged 3 times in Aedes albopictus C6/36 cells and the presence of viral growth was detected using an immunofluorescent assay. For larger quantities of viral suspensions, centrifugation on an isopycnic sucrose density gradient or cross-flow filtration was used to produce concentrated, pure antigens or partially concentrated, semi-purified antigens respectively. Results The results of the propagation experiments suggested that the maximum viral titres obtained for both Ross River virus and Barmah Forest virus were affected by the incubation period and choice of cell line, rather than the use of different multiplicity of infection values. Results of the binary ethylenimine inactivation trial suggested that standardised periods of 5 or 8 hours would be suitable to ensure effective and complete inactivation for a number of different arboviral antigens. Conclusion Two methods used to prepare inactivated arbovirus antigens have been standardised to minimise production

  1. Decay of the zincate concentration gradient at an alkaline zinc cathode after charging

    NASA Technical Reports Server (NTRS)

    Kautz, H. E.; May, C. E.

    1979-01-01

    The study was carried out by observing the decay of the zincate concentration gradient at a horizontal zinc cathode after charging. This decay was found to approximate first order kinetics as expected from a proposed boundary layer model. The decay half life was shown to be a linear function of the thickness of porous zinc deposit on the cathode indicating a very rapid transport of zincate through porous zinc metal. The rapid transport is attributed to an electrochemical mechanism. The data also indicated a relatively sharp transition between the diffusion and convection transport regions. The diffusion of zincate ion through asbestos submerged in alkaline electrolyte was shown to be comparable with that predicted from the bulk diffusion coefficient of the zincate ion in alkali.

  2. Decay of the zincate concentration gradient at an alkaline zinc cathode after charging

    NASA Technical Reports Server (NTRS)

    Kautz, H. E.; May, C. E.

    1979-01-01

    The transport of the zincate ion to the alkaline zinc cathode was studied by observing the decay of the zincate concentration gradient at a horizontal zinc cathode after charging. This decay was found to approximate first order kinetics as expected from a proposed boundary layer model. The concentrations were calculated from polarization voltages. The decay half life was shown to be a linear function of the thickness of porous zinc deposit on the cathode indicating a very rapid transport of zincate through porous zinc metal. The rapid transport is attributed to an electrochemical mechanism. From the linear dependence of the half life on the thickness the boundary layer thickness was found to be about 0.010 cm when the cathode was at the bottom of the cell. No significant dependence of the boundary layer thickness on the viscosity of electrolyte was observed. The data also indicated a relatively sharp transition between the diffusion and convection transport regions. When the cathode was at the top of the cell, the boundary layer thickness was found to be roughly 0.080 cm. The diffusion of zincate ion through asbestos submerged in alkaline electrolyte was shown to be comparable with that predicted from the bulk diffusion coefficient of the zincate ion in alkali.

  3. Changes in bryophyte and lichen communities on Scots pines along an alkaline dust pollution gradient.

    PubMed

    Degtjarenko, Polina; Marmor, Liis; Randlane, Tiina

    2016-09-01

    Dust pollution can cause a significant damage of environment and endanger human health. Our study aimed to investigate epiphytic lichens and bryophytes in relation to long-term alkaline dust pollution and provide new insights into the bioindicators of dust pollution. We measured the bark pH of Scots pines and the species richness and cover of two cryptogam groups in 32 sample plots in the vicinity of limestone quarries (up to ca. 3 km) in northern Estonia. The bark pH decreased gradually with increasing distance from quarries. We recorded the changes in natural epiphytic communities, resulting in diversified artificial communities on pines near the pollution source; the distance over 2 km from the quarries was sufficient to re-establish the normal acidity of the bark and natural communities of both lichens and bryophytes. The cover of lichens and the number of bryophytes are a more promising indicator of environmental conditions than individual species occurrence. We confirmed previously proposed and suggested new bioindicator species of dust pollution (e.g., Lecidella elaeochroma, Opegrapha varia, Schistidium apocarpum). Limestone quarrying activity revealed a "parapositive" impact on cryptogamic communities, meaning that quarrying might, besides disturbances of natural communities, temporarily contribute to the distribution of locally rare species. PMID:27230146

  4. Changes in bryophyte and lichen communities on Scots pines along an alkaline dust pollution gradient.

    PubMed

    Degtjarenko, Polina; Marmor, Liis; Randlane, Tiina

    2016-09-01

    Dust pollution can cause a significant damage of environment and endanger human health. Our study aimed to investigate epiphytic lichens and bryophytes in relation to long-term alkaline dust pollution and provide new insights into the bioindicators of dust pollution. We measured the bark pH of Scots pines and the species richness and cover of two cryptogam groups in 32 sample plots in the vicinity of limestone quarries (up to ca. 3 km) in northern Estonia. The bark pH decreased gradually with increasing distance from quarries. We recorded the changes in natural epiphytic communities, resulting in diversified artificial communities on pines near the pollution source; the distance over 2 km from the quarries was sufficient to re-establish the normal acidity of the bark and natural communities of both lichens and bryophytes. The cover of lichens and the number of bryophytes are a more promising indicator of environmental conditions than individual species occurrence. We confirmed previously proposed and suggested new bioindicator species of dust pollution (e.g., Lecidella elaeochroma, Opegrapha varia, Schistidium apocarpum). Limestone quarrying activity revealed a "parapositive" impact on cryptogamic communities, meaning that quarrying might, besides disturbances of natural communities, temporarily contribute to the distribution of locally rare species.

  5. Direct measurement of tubulin and bulk message distributions on polysomes of growing, starved and deciliated Tetrahymena using RNA gel blots of sucrose gradients containing acrylamide.

    PubMed

    Calzone, F J; Callahan, R; Gorovsky, M A

    1988-10-25

    A method was developed using sucrose gradients containing acrylamide which greatly simplifies the measurement of the polysomal distribution of messages. After centrifugation, the acrylamide was polymerized, forming a "polysome gel". RNA gel blots of polysome gels were used to determine the polysomal distributions of alpha-tubulin and total polyadenylated mRNA in growing, starved (nongrowing) and starved-deciliated Tetrahymena and the number of messages loaded onto polysomes was calculated. These measurements indicated that the translational efficiencies of alpha-tubulin mRNA and total polyadenylated mRNA are largely unaffected when the rates of tubulin and total protein synthesis vary dramatically. Thus, differential regulation of alpha-tubulin mRNA translation initiation does not contribute to the greater than 100-fold induction of tubulin synthesis observed during cilia regeneration and in growing cells. The major translation-level process regulating tubulin synthesis in Tetrahymena appears to be a change in message loading mediated by a non-specific message recruitment or unmasking factor.

  6. Use of leaf litter breakdown and macroinvertebrates to evaluate gradient of recovery in an acid mine impacted stream remediated with an active alkaline doser.

    PubMed

    Johnson, Kelly S; Thompson, Peter C; Gromen, Lori; Bowman, Jen

    2014-07-01

    The spatial congruence of chemical and biological recovery along an 18-km acid mine impaired stream was examined to evaluate the efficacy of treatment with an alkaline doser. Two methods were used to evaluate biological recovery: the biological structure of the benthic macroinvertebrate community and several ecosystem processing measures (leaf litter breakdown, microbial respiration rates) along the gradient of improved water chemistry. We found that the doser successfully reduced the acidity and lowered dissolved metals (Al, Fe, and Mn), but downstream improvements were not linear. Water chemistry was more variable, and precipitated metals were elevated in a 3-5-km "mixing zone" immediately downstream of the doser, then stabilized into a "recovery zone" 10-18 km below the doser. Macroinvertebrate communities exhibited a longitudinal pattern of recovery, but it did not exactly match the water chemistry gradient Taxonomic richness (number of families) recovered about 6.5 km downstream of the doser, while total abundance and % EPT taxa recovery were incomplete except at the most downstream site, 18 km away. The functional measures of ecosystem processes (leaf litter breakdown, microbial respiration of conditioned leaves, and shredder biomass) closely matched the measures of community structure and also showed a more modest longitudinal trend of biological recovery than expected based on pH and alkalinity. The measures of microbial respiration had added diagnostic value and indicated that biological recovery downstream of the doser is limited by factors other than habitat and acidity/alkalinity, perhaps episodes of AMD and/or impaired energy/nutrient inputs. A better understanding of the factors that govern spatial and temporal variations in acid mine contaminants, especially episodic events, will improve our ability to predict biological recovery after remediation.

  7. Inhibition of sucrose phosphatase by sucrose

    PubMed Central

    Hawker, J. S.

    1967-01-01

    1. Partially purified sucrose phosphatase from immature stem tissue of sugarcane is inhibited by sucrose. The enzyme was also inhibited by maltose, melezitose and 6-kestose but not by eight other sugars, including glucose and fructose. 2. The relative effectiveness of sucrose, maltose and melezitose as inhibitors is different for sucrose phosphatase from different plants. 3. The inhibition of the sugar-cane enzyme by sucrose was shown to be partially competitive. The Ki for sucrose is about 10mm. 4. Melezitose is also a partially competitive inhibitor of the enzyme but the inhibition by maltose is probably mixed. 5. The possibility that sucrose controls both the rate of accumulation of sucrose in stems of sugar-cane and sucrose synthesis in leaves by inhibiting sucrose phosphatase is discussed. PMID:4291490

  8. Comparative studies on the lysosomal association of monomeric /sup 239/Pu and /sup 241/Am in rat and Chinese hamster liver: analysis with sucrose, metrizamide, and Percoll density gradients of subcellular binding as dependent on time

    SciTech Connect

    Suetterlin, U.; Thies, W.G.; Haffner, H.; Seidel, A.

    1984-05-01

    The binding of /sup 239/Pu and /sup 241/Am in the livers of Chinese hamsters and rats was analyzed by centrifugation of a mitochondrial-lysosomal fraction in sucrose, metrizamide, and Percoll density gradients at intervals between 4 and 70 days after nuclide injection. The behavior of /sup 239/Pu and /sup 241/Am during the centrifugation experiments was very similar. In contrast to the results for rats, the median densities of the nuclide fraction liberated by addition of Triton X-100, and the nuclide profiles do not respond typically to Triton WR 1339 treatment of the animals. It was concluded from the results that the major fraction of /sup 239/Pu and /sup 241/Am remained bound to typical lysosomes in rat liver, whereas those in hamster liver may be transformed into telolysosomes. Possibly, a vesicular biliary transport system for certain heavy metals, for which evidence exists in rat liver, does not occur in Chinese hamster liver.

  9. Sucrose metabolism in lima bean seeds

    SciTech Connect

    Xu, Dianpeng; Sung, Shijean, S.; Black, C.C. )

    1989-04-01

    Developing and germinating lima bean (Phaseolus lunatus var Cangreen) seeds were used for testing the sucrose synthase pathway, to examine the competition for uridine diphosphate (UDP) and pyrophosphate (PPi), and to identify adaptive and maintenance-type enzymes in glycolysis and gluconeogenesis. In developing seeds, sucrose breakdown was dominated by the sucrose synthase pathway; but in the seedling embryos, both the sucrose synthase pathway and acid invertase were active. UDPase activity was low and seemingly insufficient to compete for UDP during sucrose metabolism in seed development or germination. In contrast, both an acid and alkaline pyrophosphatase were active in seed development and germination. The set of adaptive enzymes identified in developing seeds were sucrose synthase, PPi-dependent phosphofructokinase, plus acid and alkaline pyrophosphatase; and, the adaptive enzymes identified in germinating seeds included the same set of enzymes plus acid invertase. The set of maintenance enzymes identified during development, in the dry seed, and during germination were UDP-glucopyrophosphorylase, neutral invertase, ATP and UTP-dependent fructokinase, glucokinase, phosphoglucomutase, ATP and UTP-dependent phosphofructokinase and sucrose-P synthase.

  10. Sucrose metabolism in lima bean seeds.

    PubMed

    Xu, D P; Sung, S J; Black, C C

    1989-04-01

    Developing and germinating lima bean (Phaseolus lunatus var Cangreen) seeds were used for testing the sucrose synthase pathway, to examine the competition for uridine diphosphate (UDP) and pyrophosphate (PPi), and to identify adaptive and maintenance-type enzymes in glycolysis and gluconeogenesis. In developing seeds, sucrose breakdown was dominated by the sucrose synthase pathway; but in the seedling embryos, both the sucrose synthase pathway and acid invertase were active. UDPase activity was low and seemingly insufficient to compete for UDP during sucrose metabolism in seed development or germination. In contrast, both an acid and alkaline pyrophosphatase were active in seed development and germination. The set of adaptive enzymes identified in developing seeds were sucrose synthase, PPi-dependent phosphofructokinase, plus acid and alkaline pyrophosphatase; and, the adaptive enzymes identified in germinating seeds included the same set of enzymes plus acid invertase. The set of maintenance enzymes identified during development, in the dry seed, and during germination were UDP-glucopyrophosphorylase, neutral invertase, ATP and UTP-dependent fructokinase, glucokinase, phosphoglucomutase, ATP and UTP-dependent phosphofructokinase and sucrose-P synthase.

  11. Bar-coded pyrosequencing reveals shared bacterial community properties along the temperature gradients of two alkaline hot springs in Yellowstone National Park.

    PubMed

    Miller, Scott R; Strong, Aaron L; Jones, Kenneth L; Ungerer, Mark C

    2009-07-01

    An understanding of how communities are organized is a fundamental goal of ecology but one which has historically been elusive for microbial systems. We used a bar-coded pyrosequencing approach targeting the V3 region of the bacterial small-subunit rRNA gene to address the factors that structure communities along the thermal gradients of two alkaline hot springs in the Lower Geyser Basin of Yellowstone National Park. The filtered data set included a total of nearly 34,000 sequences from 39 environmental samples. Each was assigned to one of 391 operational taxonomic units (OTUs) identified by their unique V3 sequence signatures. Although the two hot springs differed in their OTU compositions, community resemblance and diversity changed with strikingly similar dynamics along the two outflow channels. Two lines of evidence suggest that these community properties are controlled primarily by environmental temperature. First, community resemblance decayed exponentially with increasing differences in temperature between samples but was only weakly correlated with physical distance. Second, diversity decreased with increasing temperature at the same rate along both gradients but was uncorrelated with other measured environmental variables. This study also provides novel insights into the nature of the ecological interactions among important taxa in these communities. A strong negative association was observed between cyanobacteria and the Chloroflexi, which together accounted for approximately 70% of the sequences sampled. This pattern contradicts the longstanding hypothesis that coadapted lineages of these bacteria maintain tightly cooccurring distributions along these gradients as a result of a producer-consumer relationship. We propose that they instead compete for some limiting resource(s).

  12. Bar-coded pyrosequencing reveals shared bacterial community properties along the temperature gradients of two alkaline hot springs in Yellowstone National Park.

    PubMed

    Miller, Scott R; Strong, Aaron L; Jones, Kenneth L; Ungerer, Mark C

    2009-07-01

    An understanding of how communities are organized is a fundamental goal of ecology but one which has historically been elusive for microbial systems. We used a bar-coded pyrosequencing approach targeting the V3 region of the bacterial small-subunit rRNA gene to address the factors that structure communities along the thermal gradients of two alkaline hot springs in the Lower Geyser Basin of Yellowstone National Park. The filtered data set included a total of nearly 34,000 sequences from 39 environmental samples. Each was assigned to one of 391 operational taxonomic units (OTUs) identified by their unique V3 sequence signatures. Although the two hot springs differed in their OTU compositions, community resemblance and diversity changed with strikingly similar dynamics along the two outflow channels. Two lines of evidence suggest that these community properties are controlled primarily by environmental temperature. First, community resemblance decayed exponentially with increasing differences in temperature between samples but was only weakly correlated with physical distance. Second, diversity decreased with increasing temperature at the same rate along both gradients but was uncorrelated with other measured environmental variables. This study also provides novel insights into the nature of the ecological interactions among important taxa in these communities. A strong negative association was observed between cyanobacteria and the Chloroflexi, which together accounted for approximately 70% of the sequences sampled. This pattern contradicts the longstanding hypothesis that coadapted lineages of these bacteria maintain tightly cooccurring distributions along these gradients as a result of a producer-consumer relationship. We propose that they instead compete for some limiting resource(s). PMID:19429553

  13. Sucrose and Related Oligosaccharides

    NASA Astrophysics Data System (ADS)

    Eggleston, Gillian

    Sucrose (α-D-glucopyranosyl-(1↔2)-β-D-fructofuranoside) is the most common low-molecular-weight sugar found in the plant kingdom. It is ubiquitously known as common table sugar and primarily produced industrially from sugarcane (Saccharum officinarum) and sugar beet (Beta vulgaris); the basics of the industrial manufacture of sucrose are outlined in this chapter. Commercial sucrose has a very high purity (> 99.9%) making it one of the purest organic substances produced on an industrial scale. Value-addition to sucrose via chemical and biotechnological reactions is becoming more important for the diversification of the sugar industry to maintain the industries' competitiveness in a world increasingly turning to a bio-based economy. The basis for the chemical reactivity of sucrose is the eight hydroxyl groups present on the molecule, although, sucrose chemical reactivity is regarded as difficult. Increasing use of enzymatic biotechnological techniques to derivatize sucrose is expected, to add special functionalities to sucrose products like biodegradability, biocompatibility, and non-toxicity. Analysis of sucrose by colorimetric, enzymatic, oxidation-reduction and chromatography methods are discussed. Oligosaccharides related to sucrose are outlined in detail and include sucrose-based plant, honey and in vitro oligosaccharides.

  14. Sucrose signaling in plants

    PubMed Central

    Tognetti, Jorge A.; Pontis, Horacio G.; Martínez-Noël, Giselle M.A.

    2013-01-01

    The role of sucrose as a signaling molecule in plants was originally proposed several decades ago. However, recognition of sucrose as a true signal has been largely debated and only recently this role has been fully accepted. The best-studied cases of sucrose signaling involve metabolic processes, such as the induction of fructan or anthocyanin synthesis, but a large volume of scattered information suggests that sucrose signals may control a vast array of developmental processes along the whole life cycle of the plant. Also, wide gaps exist in our current understanding of the intracellular steps that mediate sucrose action. Sucrose concentration in plant tissues tends to be directly related to light intensity, and inversely related to temperature, and accordingly, exogenous sucrose supply often mimics the effect of high light and cold. However, many exceptions to this rule seem to occur due to interactions with other signaling pathways. In conclusion, the sucrose role as a signal molecule in plants is starting to be unveiled and much research is still needed to have a complete map of its significance in plant function. PMID:23333971

  15. Kinetic model of sucrose accumulation in maturing sugarcane culm tissue.

    PubMed

    Uys, Lafras; Botha, Frederik C; Hofmeyr, Jan-Hendrik S; Rohwer, Johann M

    2007-01-01

    Biochemically, it is not completely understood why or how commercial varieties of sugarcane (Saccharum officinarum) are able to accumulate sucrose in high concentrations. Such concentrations are obtained despite the presence of sucrose synthesis/breakdown cycles (futile cycling) in the culm of the storage parenchyma. Given the complexity of the process, kinetic modelling may help to elucidate the factors governing sucrose accumulation or direct the design of experimental optimisation strategies. This paper describes the extension of an existing model of sucrose accumulation (Rohwer, J.M., Botha, F.C., 2001. Analysis of sucrose accumulation in the sugar cane culm on the basis of in vitro kinetic data. Biochem. J. 358, 437-445) to account for isoforms of sucrose synthase and fructokinase, carbon partitioning towards fibre formation, and the glycolytic enzymes phosphofructokinase (PFK), pyrophosphate-dependent PFK and aldolase. Moreover, by including data on the maximal activity of the enzymes as measured in different internodes, a growth model was constructed that describes the metabolic behaviour as sugarcane parenchymal tissue matures from internodes 3-10. While there was some discrepancy between modelled and experimentally determined steady-state sucrose concentrations in the cytoplasm, steady-state fluxes showed a better fit. The model supports a hypothesis of vacuolar sucrose accumulation against a concentration gradient. A detailed metabolic control analysis of sucrose synthase showed that each isoform has a unique control profile. Fructose uptake by the cell and sucrose uptake by the vacuole had a negative control on the futile cycling of sucrose and a positive control on sucrose accumulation, while the control profile for neutral invertase was reversed. When the activities of these three enzymes were changed from their reference values, the effects on futile cycling and sucrose accumulation were amplified. The model can be run online at the JWS Online

  16. Iron Sucrose Injection

    MedlinePlus

    ... often you receive iron sucrose injection and your total number of doses based on your condition and ... hands or feet; swelling of the hands, feet, ankles, or lower legs; loss of consciousness; or seizures. ...

  17. Sucrose transporters of higher plants.

    PubMed

    Kühn, Christina; Grof, Christopher P L

    2010-06-01

    Recent advances have provided new insights into how sucrose is moved from sites of synthesis to sites of utilisation or storage in sink organs. Sucrose transporters play a central role, as they orchestrate sucrose allocation both intracellularly and at the whole plant level. Sucrose produced in mesophyll cells of leaves may be effluxed into the apoplasm of mesophyll or phloem parenchyma cells by a mechanism that remains elusive, but experimentally consistent with facilitated transport or energy-dependent sucrose/H(+) antiport. From the apoplasm, sucrose/H(+) symporters transport sucrose across the plasma membrane of cells making up the sieve element/companion cell (SE/CC) complex, the long distance conduits of the phloem. Phloem unloading of sucrose in key sinks such as developing seeds involves two sequential transport steps, sucrose efflux followed by sucrose influx. Besides plasma membrane specific sucrose transporters, sucrose transporters on the tonoplast contribute to the capacity for elevated sucrose accumulation in storage organs such as sugar beet roots or sugarcane culms. Except for several sucrose facilitators from seed coats of some leguminous plants all sucrose transporters cloned to date, including recently identified vacuolar sucrose transporters, have been characterised as sucrose/H(+) symporters. Transporters functioning to efflux sucrose into source or sink apoplasms as well as those supporting sucrose/H(+) antiport on tonoplasts, remain to be identified. Sucrose transporter expression and activity is tightly regulated at the transcriptional, post-transcriptional as well as post-translational levels. Light quality and phytohormones play essential regulatory roles and the sucrose molecule itself functions as a signal.

  18. Effects of Soil Salinity on Sucrose Metabolism in Cotton Fiber

    PubMed Central

    Liu, Jingran; Luo, Junyu; Zhao, Xinhua; Dong, Helin; Ma, Yan; Sui, Ning; Zhou, Zhiguo; Meng, Yali

    2016-01-01

    Cotton (Gosspium hirsutum L.) is classified as a salt tolerant crop. However, its yield and fiber quality are negatively affected by soil salinity. Studies on the enzymatic differences in sucrose metabolism under different soil salinity levels are lacking. Therefore, field experiments, using two cotton cultivars, CCRI-79 (salt-tolerant) and Simian 3 (salt-sensitive), were conducted in 2013 and 2014 at three different salinity levels (1.15 dS m-1 [low soil salinity], 6.00 dS m-1 [medium soil salinity], and 11.46 dS m-1 [high soil salinity]). The objective was to elucidate the effects of soil salinity on sucrose content and the activity of key enzymes that are related to sucrose metabolism in cotton fiber. Results showed that as the soil salinity increased, cellulose content, sucrose content, and sucrose transformation rate declined; the decreases in cellulose content and sucrose transformation rate caused by the increase in soil salinity were more in Simian 3 than those in CCRI-79. With increase in soil salinity, activities of sucrose metabolism enzymes sucrose phophate synthase (SPS), acidic invertase, and alkaline invertase were decreased, whereas sucrose synthase (SuSy) activity increased. However, the changes displayed in the SuSy and SPS activities in response to increase in soil salinity were different and the differences were large between the two cotton cultivars. These results illustrated that suppressed cellulose synthesis and sucrose metabolism under high soil salinity were mainly due to the change in SPS, SuSy, and invertase activities, and the difference in cellulose synthesis and sucrose metabolism in fiber for the two cotton cultivars in response to soil salinity was determined mainly by both SuSy and SPS activities. PMID:27227773

  19. Effects of Soil Salinity on Sucrose Metabolism in Cotton Fiber.

    PubMed

    Peng, Jun; Zhang, Lei; Liu, Jingran; Luo, Junyu; Zhao, Xinhua; Dong, Helin; Ma, Yan; Sui, Ning; Zhou, Zhiguo; Meng, Yali

    2016-01-01

    Cotton (Gosspium hirsutum L.) is classified as a salt tolerant crop. However, its yield and fiber quality are negatively affected by soil salinity. Studies on the enzymatic differences in sucrose metabolism under different soil salinity levels are lacking. Therefore, field experiments, using two cotton cultivars, CCRI-79 (salt-tolerant) and Simian 3 (salt-sensitive), were conducted in 2013 and 2014 at three different salinity levels (1.15 dS m-1 [low soil salinity], 6.00 dS m-1 [medium soil salinity], and 11.46 dS m-1 [high soil salinity]). The objective was to elucidate the effects of soil salinity on sucrose content and the activity of key enzymes that are related to sucrose metabolism in cotton fiber. Results showed that as the soil salinity increased, cellulose content, sucrose content, and sucrose transformation rate declined; the decreases in cellulose content and sucrose transformation rate caused by the increase in soil salinity were more in Simian 3 than those in CCRI-79. With increase in soil salinity, activities of sucrose metabolism enzymes sucrose phophate synthase (SPS), acidic invertase, and alkaline invertase were decreased, whereas sucrose synthase (SuSy) activity increased. However, the changes displayed in the SuSy and SPS activities in response to increase in soil salinity were different and the differences were large between the two cotton cultivars. These results illustrated that suppressed cellulose synthesis and sucrose metabolism under high soil salinity were mainly due to the change in SPS, SuSy, and invertase activities, and the difference in cellulose synthesis and sucrose metabolism in fiber for the two cotton cultivars in response to soil salinity was determined mainly by both SuSy and SPS activities. PMID:27227773

  20. Computer simulation of immobilized pH gradients at acidic and alkaline extremes - A quest for extended pH intervals

    NASA Technical Reports Server (NTRS)

    Mosher, Richard A.; Bier, Milan; Righetti, Pier Giorgio

    1986-01-01

    Computer simulations of the concentration profiles of simple biprotic ampholytes with Delta pKs 1, 2, and 3, on immobilized pH gradients (IPG) at extreme pH values (pH 3-4 and pH 10-11) show markedly skewed steady-state profiles with increasing kurtosis at higher Delta pK values. Across neutrality, all the peaks are symmetric irrespective of their Delta pK values, but they show very high contribution to the conductivity of the background gel and significant alteration of the local buffering capacity. The problems of skewness, due to the exponential conductivity profiles at low and high pHs, and of gel burning due to a strong electroosmotic flow generated by the net charges in the gel matrix, also at low and high pHs, are solved by incorporating in the IPG gel a strong viscosity gradient. This is generated by a gradient of linear polyacrylamide which is trapped in the gel by the polymerization process.

  1. Disposition of preformed mineral in matrix vesicles. Internal localization and association with alkaline phosphatase

    SciTech Connect

    McLean, F.M.; Keller, P.J.; Genge, B.R.; Walters, S.A.; Wuthier, R.E.

    1987-08-05

    Studies were made on the disposition of mineral ions in matrix vesicles (MV) and their relationship to alkaline phosphatase by treatment of MV-enriched microsomes (MVEM) with graded levels of Ca2+-chelating agents to complex accessible ions, fractionation of MVEM on hypertonic sucrose gradients at two different pH values (7.5 and 8.0) to evaluate for the presence of calcium phosphate mineral, and passage of MVEM through cation-exchange columns to determine the accessibility of the Ca2+. The effect of removal of Ca2+ and Pi on subsequent ability of MVEM to induce mineral formation from synthetic cartilage lymph was also determined. Passage through cation-exchange columns revealed that MV Ca2+ was not freely exchangeable, but coeluted in the void volume with alkaline phosphatase. However, upon incubation in synthetic cartilage lymph, progressively more Ca2+ was retained by the column. These findings indicate that, initially, the majority of Ca2+ in MVEM is internal and not readily exchangeable, but as Ca2+ accumulates, progressively more becomes external. The mineral in MV is labile and readily susceptible to loss; treatment with graded levels of EGTA removed major portions of the original Ca2+ and Pi. 45Ca uptake by these mineral-depleted MV was markedly reduced, even in the presence of alkaline phosphatase substrates. Sucrose gradient fractionation of MVEM caused extensive loss of Pi, but not Ca2+, from the low-density alkaline phosphatase-rich fractions. This reveals that Ca2+ and Pi are not initially coupled together: Pi is largely soluble, whereas Ca2+ must be tightly bound. In the high-density vesicles, large amounts of both Ca2+ and Pi are present.

  2. Sugar (sucrose) holograms

    NASA Astrophysics Data System (ADS)

    Ponce-Lee, E. L.; Olivares-Pérez, A.; Fuentes-Tapia, I.

    2004-06-01

    Computer holograms made with sugar crystals are reported. This material is well known as a good sweetener; the sugar from sugar cane or sugar beet (sucrose). These sweetener can be applied as honey "water and diluted sugar" easily on any substrate such as plastics or glasses without critical conditions for developed process. This step corresponds only to the cured sucrose as a photopolymer process. The maximum absorption spectra is localized at UV region λ=240 nm. We record with lithographic techniques some gratings, showing a good diffraction efficiency around 45%. This material has good resolution to make diffraction gratings. These properties are attractive because they open the possibility to make phase holograms on candies. Mainly the phase modulation is by refraction index.

  3. Analysis of sucrose esters--insecticides from the surface of tobacco plant leaves.

    PubMed

    Simonovska, Breda; Srbinoska, Marija; Vovk, Irena

    2006-09-15

    Sucrose esters from the surface of leaves of Nicotiana tabacum L. have been shown to possess interesting biological activities. We developed a simple and effective method for their analysis using HPTLC silica gel plates, n-hexane-ethyl acetate (1:3, v/v) as developing solvent and aniline-diphenylamine as a detection reagent. Off-line TLC-MS was also used for the detection and identification of the compounds. Solutions containing sucrose esters upon alkaline hydrolysis give sucrose, which is used for indirect estimation by TLC of the sucrose ester content. The method is applicable for the screening for sucrose esters in plant extracts. The extract obtained from the surface of green leaves of oriental tobacco type Prilep P-23 contains sucrose esters and is effective against Myzus persicae (Sulzer) in laboratory and field experiments. PMID:16820155

  4. Hydrogen ion secretion by the collecting duct as a determinant of the urine to blood PCO2 gradient in alkaline urine

    SciTech Connect

    DuBose, T.D. Jr.

    1982-01-01

    Several theories have been advanced to explain the elevation in urinary PCO/sub 2/ during bicarbonate loading and include: (a) H+ secretion, (b) countercurrent system for CO/sub 2/, (c) the ampholyte properties of bicarbonate, and (d) mixing of urine of disparate bicarbonate and butter concentrations. In this study microelectrodes were used to measure in situ and equilibrium pH (pHis and pHeq) and PCO/sub 2/ in control and bicarbonate loaded rats before and after infusion of carbonic anhydrase. The disequilibrium pH method (pHdq . pHis - pHeq) was used to demonstrate H+ secretion. Control rats excreting an acid urine (pH . 6.04 +/- 0.06) failed to display a significant disequilibrium pH at the base (BCD), or tip (TCD) of the papillary collecting duct. Urine pH (7.54 +/- 0.12), and urine to blood (U-B) PCO/sub 2/ increased significantly during NaHCO/sub 3/ loading while PCO/sub 2/ at the BCD and TCD also increased (95 +/- 4 and 122 +/- 4). Furthermore, an acid disequilibrium pH was present at both the BCD and TCD (-0.42 +/- 0.04 and -0.36 +/- 0.03) and was obliterated by carbonic anhydrase. Comparison of the PCO/sub 2/ in the BCD or TCD with the adjacent vasa recta revealed similar values (r . 0.97). It is concluded that H+ secretion by the collecting duct into bicarbonate containing fluid with delayed dehydration of H/sub 2/CO/sub 3/, is the most likely determinant of the U-B PCO/sub 2/ in alkaline urine. Similar values for PCO/sub 2/ in the collecting duct and the adjacent vasa recta suggests trapping of CO/sub 2/ in the medullary countercurrent system. The rise in PCO/sub 2/ occurs both along the collecting duct and after exit from the papilla.

  5. A novel sucrose/H+ symport system and an intracellular sucrase in Leishmania donovani.

    PubMed

    Singh, Arpita; Mandal, Debjani

    2011-07-01

    The flagellated form of pathogenic parasitic protozoa Leishmania, resides in the alimentary tract of its sandfly vector, where sucrose serves as a major nutrient source. In this study we report the presence of a sucrose transport system in Leishmania donovani promastigotes. The kinetics of sucrose uptake in promastigotes are biphasic in nature with both high affinity K(m) (K(m) of ∼ 75 μM) and low affinity K(m) (K(m)∼ 1.38 mM) components. By contrast the virulent amastigotes take up sucrose via a low affinity process with a K(m) of 2.5mM. The transport of sucrose into promastigotes leads to rapid intracellular acidification, as indicated by changes in the fluorescence of the pH indicator 2',7'-bis-(2-carboxyethyl)-5-(6) Carboxyfluorescein (BCECF). In experiments with right side-out plasma membrane vesicles derived from L. donovani promastigotes, an artificial pH gradient was able to drive the active accumulation of sucrose. These data are consistent with the operation of a H(+)-sucrose symporter. The symporter was shown to be independent of Na(+) and to be insensitive to cytochalasin B, to the flavonoid phloretin and to the Na(+)/K(+) ATPase inhibitor ouabain. However, the protonophore carbonylcyanide P- (trifluromethoxy) phenylhydrazone (FCCP) and a number of thiol reagents caused significant inhibition of sucrose uptake. Evidence was also obtained for the presence of a stable intracellular pool of the sucrose splitting enzyme, sucrase, in promastigote stage parasites. The results are consistent with the hypothesis that L. donovani promastigotes take up sucrose via a novel H(+)-sucrose symport system and that, on entering the cell, the sucrose is hydrolysed to its component monosaccharides by an intracellular sucrase, thereby providing an energy source for the parasites. PMID:21515279

  6. Sucrose diffusion in aqueous solution.

    PubMed

    Price, Hannah C; Mattsson, Johan; Murray, Benjamin J

    2016-07-28

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes-Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  7. Sucrose diffusion in aqueous solution

    PubMed Central

    Murray, Benjamin J.

    2016-01-01

    The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes–Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

  8. ( sup 14 C)-Sucrose uptake by guard cell protoplasts of pisum sativum, argenteum mutant

    SciTech Connect

    Rohrig, K.; Raschke, K. )

    1991-05-01

    Guard cells rely on import for their supply with reduced carbon. The authors tested by silicone oil centrifugation the ability of guard cell protoplasts to accumulated ({sup 14}C)-sucrose. Uptake rates were corrected after measurement of {sup 14}C-sorbitol and {sup 3}H{sub 2}O spaces. Sucrose uptake followed biphasic kinetics, with a high-affinity component below 1 mM external sucrose (apparent K{sub m} 0.8 mM at 25C) and a low-affinity nonsaturable component above. Uptake depended on pH (optimum at pH 5.0). Variations in the concentrations of external KCl, CCCP, and valinomycin indicated that about one-half of the sucrose uptake rate could be related to an electrochemical gradient across the plasmalemma. Total uptake rates measured at 5 mM external sucrose seem to be sufficient to replenish emptied plastids with starch within a few hours.

  9. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed.

  10. Sucrose release from polysaccharide gels.

    PubMed

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed. PMID:26952168

  11. Featured Molecules: Sucrose and Vanillin

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-04-01

    The WebWare molecules of the month for April relate to the sense of taste. Apple Fool, the JCE Classroom Activity, mentions sucrose and vanillin and their use as flavorings. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  12. Purification and characterization of neutral and alkaline invertase from carrot.

    PubMed Central

    Lee, H S; Sturm, A

    1996-01-01

    Neutral and alkaline invertase were identified in cells of a suspension culture of carrot (Daucus carota L.) and purified to electrophoretic homogeneity. Neutral invertase is an octamer with a molecular mass of 456 kD and subunits of 57 kD, whereas alkaline invertase is a tetramer with a molecular mass of 504 kD and subunits of 126 kD. Both enzymes had sharp pH profiles, with maximal activities at pH 6.8 for neutral invertase and pH 8.0 for alkaline invertase, and both hydrolyzed sucrose with typical hyperbolic kinetics and similar Km values of about 20 mM at pH 7.5. Neutral invertase also hydrolyzed raffinose and stachyose and, therefore, is a beta-fructofuranosidase. In contrast, alkaline invertase was highly specific for sucrose. Fructose acted as a competitive inhibitor of both enzymes, with Ki values of about 15 mM. Glucose was a noncompetitive inhibitor of both neutral and alkaline invertase, with a Ki of about 30 mM. Neither enzyme was inhibited by HgCl2. Alkaline invertase was markedly inhibited by CaCl2, MgCl2, and MnCl2, and neutral invertase was not. In contrast to alkaline invertase, neutral invertase was inhibited by the nucleotides ATP, CTP, GTP, and UTP. PMID:8972597

  13. Effects of Sugar (Sucrose) on Children's Behavior.

    ERIC Educational Resources Information Center

    Rosen, Lee A.; And Others

    1988-01-01

    Examined effects of sugar on behavior of 45 preschool and elementary school children. Provided all children with basic breakfast that included drink containing either 50 g of sucrose, a comparably sweet placebo, or very little sucrose. Found some small behavior changes in high-sucrose group. All effects were small in magnitude and not considered…

  14. Sucrose transport into stalk tissue of sugarcane

    SciTech Connect

    Thom, M.; Maretzki, A. )

    1990-05-01

    The productivity of higher plants is, in part, dependent on transport of photosynthate from source to sink (in sugarcane, stalk) and upon its assimilation in cells of the sink tissue. In sugarcane, sucrose has been reported to undergo hydrolysis in the apoplast before uptake into the storage parenchyma, whereas recently, sucrose was reported to be taken up intact. This work was based on lack of randomization of ({sup 14}C)fructosyl sucrose accumulated after feeding tissue slices with this sugar. In this report, we present evidence from slices of stalk tissue that sucrose is taken up intact via a carrier-mediated, energy-dependent process. The evidence includes: (1) uptake of fluorosucrose, an analog of sucrose not subject to hydrolysis by invertase; (2) little or no randomization of ({sup 14}C) fructosyl sucrose taken up; (3) the presence of a saturable as well as a linear component of sucrose uptake; and (4) inhibition of both the saturable and linear components of sucrose uptake by protonophore and sulhydryl agents. Hexoses can also be taken up, and at a greater efficiency than sucrose. It is probable that both hexose and sucrose can be transported across the plasma membrane, depending on the physiological status of the plant.

  15. ALP (Alkaline Phosphatase) Test

    MedlinePlus

    ... known as: ALK PHOS; Alkp Formal name: Alkaline Phosphatase Related tests: AST ; ALT ; GGT ; Bilirubin ; Liver Panel ; Bone Markers ; Alkaline Phosphatase Isoenzymes; Bone Specific ALP All content on Lab ...

  16. Sucrose synthesis in gamma irradiated sweet potato

    SciTech Connect

    Ailouni, S.; Hamdy, M.K.; Toledo, R.T.

    1987-01-01

    Effect of ..cap alpha..-irradiation carbohydrate metabolism was examined to elucidate mechanism of sucrose accumulation in sweet potato (SP). Enzymes examined were: ..beta..-amylase, phosphorylase, phosphoglucomutase, phosphoglucose isomerase, sucrose phosphate synthetase and sucrose synthetase. Irradiated SP (Red Jewell) sucrose was synthesized to yield 10.7% after 4 d PI. Activities of sugar synthesizing enzymes in irradiated SP were enhanced to different degrees using 100-200 Krad and 3 d PI at 24/sup 0/C. Phosphorylase and phosphoglucomutases specific activities reached 2.4 and 1.8 folds, respectively compared to control SP. ..beta..-amylase, phosphoglucose isomerase, sucrose synthetase and sucrose phosphate synthetase were also affected to yield 1.2, 1.3, 1.3 and 1.2 folds, respectively compared to controls. It is believed that amylase hydrolyzed starch to glucose which is converted to fructose by phosphoglucose isomerase. Sucrose is then formed by sucrose phosphate synthetase and/or sucrose synthetase leading to its accumulation. The irradiated SP was used for alcohol fermentation leading to 500 gal. of 200 proof ethanol/acre (from 500-600 bushels tuber/acre).

  17. Sucrose induces vesicle accumulation and autophagy.

    PubMed

    Higuchi, Takahiro; Nishikawa, Jun; Inoue, Hiroko

    2015-04-01

    It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes.

  18. Sucrose induces vesicle accumulation and autophagy.

    PubMed

    Higuchi, Takahiro; Nishikawa, Jun; Inoue, Hiroko

    2015-04-01

    It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes. PMID:25389129

  19. Diffusion of Trehalose and Sucrose in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Feick, E.; von Meerwall, E.; Ekdawi, N.; de Pablo, J.

    2000-10-01

    Trehalose is emerging as superior substitute for sucrose in solution as a cryoprotectant, e. g., to preserve organs destined for transplantation. We have used the proton NMR pulsed-gradient spin-echo method between T = 30 and 85 deg. C to study the self-diffusion of solvent and solute in aqueous solutions of these molecules as function of their concentration, c. We find that both solute molecules diffuse substantially more slowly than water at corresponding c and T; that addition of water accelerates solute diffusion more rapidly than that of water; and that while at a given c and T water diffusion is insensitive to solute identity, trehalose diffusion is slower than sucrose diffusion. The latter effect increases with c, approaching a factor of two at the highest c. In these respects our results correspond closely to those of our extensive numerical simulations of these systems. Free-volume theory is employed to explore the cooperative kinetic interactions between solvent and solutes, and to account tentatively for part of the superiority of trehalose to sucrose as preservation agent. Differences in crystallization behavior also seem to be involved.

  20. Sucrose accumulation in mature sweet melon fruits. [Cucumis melo

    SciTech Connect

    Schaffer, A.A.; Aloni, B.

    1987-04-01

    Mesocarp tissue from sucrose-accumulating sweet melon (Cucumis melo cv. Galia) showed sucrose synthase activity (ca 1 nkat/gfw) while soluble acid invertase and sucrose phosphate synthase activities were not observed. Sucrose uptake into mesocarp discs was linear with sucrose concentration (1-500 mM) and unaffected by PCMBS and CCCP. Sucrose compartmentation into the vacuole also increased linearly with sucrose concentration as indicated by compartmental efflux kinetics. Mesocarp discs incubated in /sup 14/C-fructose + UDP-glu synthesized /sup 14/C-sucrose and efflux kinetics indicated that the /sup 14/C-sucrose was compartmentalized. These data support the hypothesis that two mechanisms are involved in sucrose accumulation in sweet melon: (1) compartmentation of intact sucrose and (2) synthesis of sucrose via sucrose synthase and subsequent compartmentation in the vacuole.

  1. Internalization of Sucrose by Methanococcus thermolithotrophicus

    PubMed Central

    Ciulla, R.; Krishnan, S.; Roberts, M. F.

    1995-01-01

    When sucrose is present in the external medium, it is internalized by Methanococcus thermolithotrophicus. Sucrose internalization, as determined by both natural abundance (sup13)C nuclear magnetic resonance spectroscopy and [(sup14)C]sucrose uptake, is directly proportional to external sucrose levels. The uptake is energy independent and exhibits kinetic behavior consistent with a simple passive diffusion process. In the presence of 0.2 M sucrose, methanogenesis is inhibited as the NaCl concentration in the external medium is increased. Growth, as determined by protein content, is inhibited by 0.2 M sucrose when the external NaCl concentration is 1.4 M. These results are important because they show that (i) sucrose cannot be used as a noncharged solute to replace NaCl in experiments to evaluate how external osmotic strength affects the internal solute composition of M. thermolithotrophicus, and (ii) sucrose cannot be used as an impermeable marker for the extracellular volume in experiments to measure the intracellular volume of M. thermolithotrophicus. PMID:16534924

  2. 21 CFR 184.1854 - Sucrose.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1854 Sucrose. (a) Sucrose (C12H22O11, CAS Reg. No. 57-50-11-1) sugar, cane sugar, or beet sugar is the... sugar beet juice that has been extracted by pressing or diffusion, then clarified and evaporated....

  3. Roles of sucrose in guard cell regulation.

    PubMed

    Daloso, Danilo M; Dos Anjos, Leticia; Fernie, Alisdair R

    2016-08-01

    The control of stomatal aperture involves reversible changes in the concentration of osmolytes in guard cells. Sucrose has long been proposed to have an osmolytic role in guard cells. However, direct evidence for such a role is lacking. Furthermore, recent evidence suggests that sucrose may perform additional roles in guard cells. Here, we provide an update covering the multiple roles of sucrose in guard cell regulation, highlighting the knowledge accumulated regarding spatiotemporal differences in the synthesis, accumulation, and degradation of sucrose as well as reviewing the role of sucrose as a metabolic connector between mesophyll and guard cells. Analysis of transcriptomic data from previous studies reveals that several genes encoding sucrose and hexose transporters and genes involved in gluconeogenesis, sucrose and trehalose metabolism are highly expressed in guard cells compared with mesophyll cells. Interestingly, this analysis also showed that guard cells have considerably higher expression of C4 -marker genes than mesophyll cells. We discuss the possible roles of these genes in guard cell function and the role of sucrose in stomatal opening and closure. Finally, we provide a perspective for future experiments which are required to fill gaps in our understanding of both guard cell metabolism and stomatal regulation.

  4. Sucrose-mediated transcriptional regulation of sucrose symporter activity in the phloem.

    SciTech Connect

    Matt Vaughn Greg Harrington Daniel R Bush

    2002-08-06

    This project was based on our discovery that sucrose acts as a signaling molecule that regulates the activity of a proton-sucrose symporter in sugar beet leaf tissue. A major objective here was determining how sucrose transporter activity is being regulated. When sucrose accumulates in the phloem sucrose transport activity drops dramatically. Western blots of plasma membrane proteins isolated from sucrose treated leaves showed that the loss of sucrose transport activity was proportional to a decline in symporter abundance, demonstrating that sucrose transport is regulated by changes in the amount of BvSUT1 protein. BvSUT1 transcript levels decreased in parallel with the loss of sucrose transport activity. Nuclear run-on experiments demonstrated that BvSUT1 gene transcription was repressed significantly in nuclei from leaves fed 100 mM exogenous sucrose, showing that sucrose-dependent modulation of BvSUT1 mRNA levels is mediated by changes in transcription. To identify which secondary messenger systems might be involved in regulating symporter activity, we used a variety of pharmacological agents to probe for a role of calcium or protein phosphorylation in sucrose signaling. In a detailed analysis, only okadaic acid altered sucrose transport activity. These results suggest a protein phosphatase is involved. We hypothesized that protein kinase inhibitors would have a neutral affect or increase symporter transcription. Transpirational feeding of the protein kinase inhibitor staurosporine had no impact on sucrose transport while calphostin C, an inhibitor of protein kinase C, caused a 60% increase. These data provided good evidence that protein phosphorylation plays a central role in regulating sucrose symporter expression and sucrose transport activity. To determine whether protein phosphorylation is involved in sucrose regulation of proton-sucrose symporter activity, we pre-fed leaves with staurosporine for 4 h and then fed the treated leaves water or 100 mM sucrose

  5. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    PubMed

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results. PMID:26402948

  6. [The determination of glucose, sucrose and fructose by the method of capillary electrophoresis].

    PubMed

    Yakuba, Yu F; Markovsky, M G

    2015-01-01

    The possibilities of different regimes of micellar capillary electrophoresis using negative polarity and alkaline electrolyte for determination of glucose, sucrose, fructose in extracts of vegetative organs of plants and products of fruits and grapes processing have been studied. A comparative evaluation of the limits of detection of glucose, sucrose, fructose for developed electrolytes have been performed, the advantages and disadvantages of techniques have been discussed. It is recommended to use an aqueous electrolyte containing 0.5% potassium sorbate, 0.62% cetyltrimethylammonium bromide, and 0.02% potassium hydroxide. The analyzed components were detected at 254 nm. The sample was dosed hydrodynamically (30 mbar, 5 sec). Negative voltage 16 kV is recommended, current--54 ± 4 µA, capillary thermostating at 24 °C is applied, the analysis time--15 min. The detection limits for fructose and glucose is 0.03 g/dm3 to 0.07 g of sucrose/dm3. Linearity is stored for each component to 5.0 g/dm 3 inclusive. Electrophoretic mobility of carbohydrates was (10(-4) sm2V(-1)sec(-1)): fructose--3.12, glucose--3.03, sucrose--2.74. Approximate time of release: glucose--13 min, sucrose--13.5 min, fructose--12.5 min. The developed options for mass concentration determining of mono- and disaccharides provide complete separation of the components. Anions, glycerol, ethylene glycol, propylene glycol and butylene isomers do not affect the analysis results.

  7. [Effect of exogenous sucrose on growth and active ingredient content of licorice seedlings under salt stress conditions].

    PubMed

    Liu, Fu-zhi; Yang, Jun

    2015-11-01

    Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious. PMID:27097411

  8. [Effect of exogenous sucrose on growth and active ingredient content of licorice seedlings under salt stress conditions].

    PubMed

    Liu, Fu-zhi; Yang, Jun

    2015-11-01

    Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious.

  9. Enzymatic conversion of sucrose to hydrogen

    SciTech Connect

    Woodward, J.; Orr, M.

    1998-11-01

    The enzymatic conversion of sugars to hydrogen could be a promising method for alternative fuel production. Maple tree sap is a source of environmental sugar (e.g., sucrose) that has the potential to be converted into hydrogen using the enzymes invertase, glucose dehydrogenase (GDH), hydrogenase, and glucose isomerase (GI) and the cofactor NADP{sup +}/NADPH. The kinetics of hydrogen production have been studied, and optimal conditions for hydrogen production are described. At low initial sucrose concentrations, in the absence of glucose isomerase, stoichiometric yields of mol of H{sub 2}/mol of sucrose were achieved. At higher sucrose concentrations, the yield of hydrogen declined so that at an initial sucrose concentration of 292 mM only 7% yield of hydrogen was obtained. The reason for this low yield was studied and shown not to be caused by enzyme inactivation or a pH drop during the reaction but due to an instability of the cofactor NADP{sup +}. Although gluconic and inhibited both NADPH production and oxidation of GDH and hydrogenase, respectively, it was not the major cause of NADP{sup +} instability. Fructose was also shown to be converted to hydrogen if GI was present in the reaction mixture. Also, by starting with sucrose, 1.34 mol of H{sub 2}/mol of sucrose was obtained if GI was present in the reaction mixture.

  10. [Sucrose reward promotes rats' motivation for cocaine].

    PubMed

    Li, Yan-Qing; LE, Qiu-Min; Yu, Xiang-Chen; Ma, Lan; Wang, Fei-Fei

    2016-06-25

    Caloric diet, such as fat and sugar intake, has rewarding effects, and has been indicated to affect the responses to addictive substances in animal experiments. However, the possible association between sucrose reward and the motivation for addictive drugs remains to be elucidated. Thus, we carried out behavioral tests after sucrose self-administration training to determine the effects of sucrose experience on rats' motivation for cocaine, locomotor sensitivity to cocaine, basal locomotor activity, anxiety level, and associative learning ability. The sucrose-experienced (sucrose) group exhibited higher lever press, cocaine infusion and break point, as well as upshift of cocaine dose-response curve in cocaine self-administration test, as compared with the control (chow) group. Additionally, despite similar locomotor activity in open field test and comparable score in cocaine-induced conditioned place preference, the sucrose group showed higher cocaine-induced locomotor sensitivity as compared with the chow group. The anxiety level and the performance in vocal-cue induced fear memory were similar between these two groups in elevated plus maze and fear conditioning tests, respectively. Taken together, our work indicates that sucrose experience promotes the rats' motivation for cocaine. PMID:27350195

  11. Functional Analysis of Arabidopsis Sucrose Transporters

    SciTech Connect

    John M. Ward

    2009-03-31

    Sucrose is the main photosynthetic product that is transported in the vasculature of plants. The long-distance transport of carbohydrates is required to support the growth and development of net-importing (sink) tissues such as fruit, seeds and roots. This project is focused on understanding the transport mechanism sucrose transporters (SUTs). These are proton-coupled sucrose uptake transporters (membrane proteins) that are required for transport of sucrose in the vasculature and uptake into sink tissues. The accomplishments of this project included: 1) the first analysis of substrate specificity for any SUT. This was accomplished using electrophysiology to analyze AtSUC2, a sucrose transporter from companion cells in Arabidopsis. 2) the first analysis of the transport activity for a monocot SUT. The transport kinetics and substrate specificity of HvSUT1 from barley were studied. 3) the first analysis of a sucrose transporter from sugarcane. and 4) the first analysis of transport activity of a sugar alcohol transporter homolog from plants, AtPLT5. During this period four primary research papers, funded directly by the project, were published in refereed journals. The characterization of several sucrose transporters was essential for the current effort in the analysis of structure/function for this gene family. In particular, the demonstration of strong differences in substrate specificity between type I and II SUTs was important to identify targets for site-directed mutagenesis.

  12. Characterization, localization, and seasonal changes of the sucrose transporter FeSUT1 in the phloem of Fraxinus excelsior.

    PubMed

    Öner-Sieben, Soner; Rappl, Christine; Sauer, Norbert; Stadler, Ruth; Lohaus, Gertrud

    2015-08-01

    Trees are generally assumed to be symplastic phloem loaders. A typical feature for most wooden species is an open minor vein structure with symplastic connections between mesophyll cells and phloem cells, which allow sucrose to move cell-to-cell through the plasmodesmata into the phloem. Fraxinus excelsior (Oleaceae) also translocates raffinose family oligosaccharides in addition to sucrose. Sucrose concentration was recently shown to be higher in the phloem sap than in the mesophyll cells. This suggests the involvement of apoplastic steps and the activity of sucrose transporters in addition to symplastic phloem-loading processes. In this study, the sucrose transporter FeSUT1 from F. excelsior was analysed. Heterologous expression in baker's yeast showed that FeSUT1 mediates the uptake of sucrose. Immunohistochemical analyses revealed that FeSUT1 was exclusively located in phloem cells of minor veins and in the transport phloem of F. excelsior. Further characterization identified these cells as sieve elements and possibly ordinary companion cells but not as intermediary cells. The localization and expression pattern point towards functions of FeSUT1 in phloem loading of sucrose as well as in sucrose retrieval. FeSUT1 is most likely responsible for the observed sucrose gradient between mesophyll and phloem. The elevated expression level of FeSUT1 indicated an increased apoplastic carbon export activity from the leaves during spring and late autumn. It is hypothesized that the importance of apoplastic loading is high under low-sucrose conditions and that the availability of two different phloem-loading mechanisms confers advantages for temperate woody species like F. excelsior.

  13. Characterization, localization, and seasonal changes of the sucrose transporter FeSUT1 in the phloem of Fraxinus excelsior

    PubMed Central

    Öner-Sieben, Soner; Rappl, Christine; Sauer, Norbert; Stadler, Ruth; Lohaus, Gertrud

    2015-01-01

    Trees are generally assumed to be symplastic phloem loaders. A typical feature for most wooden species is an open minor vein structure with symplastic connections between mesophyll cells and phloem cells, which allow sucrose to move cell-to-cell through the plasmodesmata into the phloem. Fraxinus excelsior (Oleaceae) also translocates raffinose family oligosaccharides in addition to sucrose. Sucrose concentration was recently shown to be higher in the phloem sap than in the mesophyll cells. This suggests the involvement of apoplastic steps and the activity of sucrose transporters in addition to symplastic phloem-loading processes. In this study, the sucrose transporter FeSUT1 from F. excelsior was analysed. Heterologous expression in baker’s yeast showed that FeSUT1 mediates the uptake of sucrose. Immunohistochemical analyses revealed that FeSUT1 was exclusively located in phloem cells of minor veins and in the transport phloem of F. excelsior. Further characterization identified these cells as sieve elements and possibly ordinary companion cells but not as intermediary cells. The localization and expression pattern point towards functions of FeSUT1 in phloem loading of sucrose as well as in sucrose retrieval. FeSUT1 is most likely responsible for the observed sucrose gradient between mesophyll and phloem. The elevated expression level of FeSUT1 indicated an increased apoplastic carbon export activity from the leaves during spring and late autumn. It is hypothesized that the importance of apoplastic loading is high under low-sucrose conditions and that the availability of two different phloem-loading mechanisms confers advantages for temperate woody species like F. excelsior. PMID:26022258

  14. Anodes for alkaline electrolysis

    DOEpatents

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  15. Alkaline "Permanent" Paper.

    ERIC Educational Resources Information Center

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and recyclability is…

  16. 21 CFR 184.1854 - Sucrose.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... sugar, or beet sugar is the chemical β-D-fructofuranosyl-α-D-glucopyranoside. Sucrose is obtained by crystallization from sugar cane or sugar beet juice that has been extracted by pressing or diffusion,...

  17. 21 CFR 184.1854 - Sucrose.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... sugar, or beet sugar is the chemical β-D-fructofuranosyl-α-D-glucopyranoside. Sucrose is obtained by crystallization from sugar cane or sugar beet juice that has been extracted by pressing or diffusion,...

  18. 21 CFR 184.1854 - Sucrose.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... sugar, or beet sugar is the chemical β-D-fructofuranosyl-α-D-glucopyranoside. Sucrose is obtained by crystallization from sugar cane or sugar beet juice that has been extracted by pressing or diffusion,...

  19. 21 CFR 184.1854 - Sucrose.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... sugar, or beet sugar is the chemical β-D-fructofuranosyl-α-D-glucopyranoside. Sucrose is obtained by crystallization from sugar cane or sugar beet juice that has been extracted by pressing or diffusion,...

  20. A specific sucrose phosphatase from plant tissues

    PubMed Central

    Hawker, J. S.; Hatch, M. D.

    1966-01-01

    1. A phosphatase that hydrolyses sucrose phosphate (phosphorylated at the 6-position of fructose) was isolated from sugar-cane stem and carrot roots. With partially purified preparations fructose 6-phosphate, glucose 6-phosphate, fructose 1-phosphate, glucose 1-phosphate and fructose 1,6-diphosphate are hydrolysed at between 0 and 2% of the rate for sucrose phosphate. 2. The activity of the enzyme is increased fourfold by the addition of Mg2+ ions and inhibited by EDTA, fluoride, inorganic phosphate, pyrophosphate, Ca2+ and Mn2+ ions. Sucrose (50mm) reduces activity by 60%. 3. The enzyme exhibits maximum activity between pH6·4 and 6·7. The Michaelis constant for sucrose phosphate is between 0·13 and 0·17mm. 4. At least some of the specific phosphatase is associated with particles having the sedimentation properties of mitochondria. 5. A similar phosphatase appears to be present in several other plant species. PMID:4290548

  1. 21 CFR 172.869 - Sucrose oligoesters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... It is produced by interesterification of sucrose with methyl esters of fatty acids derived from... incorporated by reference, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the methods may...

  2. 21 CFR 172.869 - Sucrose oligoesters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... It is produced by interesterification of sucrose with methyl esters of fatty acids derived from... incorporated by reference, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the methods may...

  3. Intracellular sucrose communicates metabolic demand to sucrose transporters in developing pea cotyledons.

    PubMed

    Zhou, Yuchan; Chan, Katie; Wang, Trevor L; Hedley, Cliff L; Offler, Christina E; Patrick, John W

    2009-01-01

    Mechanistic inter-relationships in sinks between sucrose compartmentation/metabolism and phloem unloading/translocation are poorly understood. Developing grain legume seeds provide tractable experimental systems to explore this question. Metabolic demand by cotyledons is communicated to phloem unloading and ultimately import by sucrose withdrawal from the seed apoplasmic space via a turgor-homeostat mechanism. What is unknown is how metabolic demand is communicated to cotyledon sucrose transporters responsible for withdrawing sucrose from the apoplasmic space. This question was explored here using a pea rugosus mutant (rrRbRb) compromised in starch biosynthesis compared with its wild-type counterpart (RRRbRb). Sucrose influx into cotyledons was found to account for 90% of developmental variations in their absolute growth and hence starch biosynthetic rates. Furthermore, rr and RR cotyledons shared identical response surfaces, indicating that control of transporter activity was likely to be similar for both lines. In this context, sucrose influx was correlated positively with expression of a sucrose/H(+) symporter (PsSUT1) and negatively with two sucrose facilitators (PsSUF1 and PsSUF4). Sucrose influx exhibited a negative curvilinear relationship with cotyledon concentrations of sucrose and hexoses. In contrast, the impact of intracellular sugars on transporter expression was transporter dependent, with expression of PsSUT1 inhibited, PsSUF1 unaffected, and PsSUF4 enhanced by sugars. Sugar supply to, and sugar concentrations of, RR cotyledons were manipulated using in vitro pod and cotyledon culture. Collectively the results obtained showed that intracellular sucrose was the physiologically active sugar signal that communicated metabolic demand to sucrose influx and this transport function was primarily determined by PsSUT1 regulated at the transcriptional level.

  4. Structural development of sucrose-sweetened and sucrose-free sponge cakes during baking.

    PubMed

    Baeva, Marianna Rousseva; Terzieva, Vesselina Velichkova; Panchev, Ivan Nedelchev

    2003-06-01

    The influence of sucrose, wheat starch and sorbitol upon the heat- and mass-exchanging processes forming the structure of sponge cake was studied. Under the influence of wheat starch and sorbitol the structure of the sucrose-free sponge cake was formed at more uniform total moisture release. This process was done at lower temperatures and smoother change of the sponge cake height with respect to the sucrose-sweetened sponge cake. The porous and steady structure of both cakes was finally formed at identical time--between 18th and 19th minute, at the applied conditions for baking of each batter (metal pan with diameter 15.4 cm and depth 6.2 cm containing 300 g of batter and placed in an electric oven "Rahovetz-02", Bulgaria for 30 min at 180 degrees C). The water-losses at the end of baking (10.30% and 10.40% for the sucrose-sweetened cake and sucrose-free cake, respectively) and the final temperatures reached in the crumb central layers (96.6 degrees C and 96.3 degrees C for the sucrose-sweetened cake and sucrose-free cake, respectively) during baking of both samples were not statistically different. The addition of wheat starch and sorbitol in sucrose-free sponge cake lead to the statistically different values for the porosity (76.15% and 72.98%) and the volume (1014.17 cm3 and 984.25 cm3) of the sucrose-sweetened and sucrose-free sponge cakes, respectively. As a result, the sucrose-free sponge cake formed during baking had a more homogeneous and finer microstructure with respect to that ofthe sucrose-sweetened one.

  5. Identification of sucrose binding, membrane proteins using a photolyzable sucrose analog. [P. saccharophila

    SciTech Connect

    Ripp, K.G.; Liu, D.F.; Viitanen, P.; Hitz, W.D.

    1986-04-01

    The sucrose derivative 6'-deoxy-6'-(2-hydroxy-4-azido)benzamidosucrose (6'-HABS) was prepared from sucrose (via 6'-deoxy-6'-aminosucrose) and 4-amino-salicylic acid. 6'-HABS is a competitive inhibitor of sucrose influx into protoplasts from developing soybean cotyledons and of sucrose binding to membranes from the bacteria P. saccharophila. The Ki for inhibition in the soybean protoplasts was 75..mu..M. 6'-Deoxy-6'-(2-hydroxy-3-/sup 125/Iodo-4-azido)benzamidosucrose was prepared by lactoperoxidase iodination of 6'-HABS. Upon photolysis in the presence of membranes from P saccharophila, label from the photoprobe is incorporated into a sucrose inducible polypeptide of mass 84 KD in SDS-PAGE. The polypeptide is protected from labeling by the inclusion of sucrose in the photolysis mixture. Photolysis conditions which lead to specific labeling of the sucrose protectable polypeptide in bacterial membranes also give sucrose protectable labeling of a 66 KD polypeptide in microsomal preparations made from developing soybeans. The possibility that this is a sucrose transporting protein is being tested.

  6. Application of diffusion ordered-1H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages.

    PubMed

    Cao, Ruge; Nonaka, Airi; Komura, Fusae; Matsui, Toshiro

    2015-03-15

    This work focuses on a quantitative analysis of sucrose using diffusion ordered-quantitative (1)H-nuclear magnetic resonance spectroscopy (DOSY-qNMR), where an analyte can be isolated from interference based on its characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of sucrose in deuterium oxide at 30°C was 4.9 × 10(-10)m(2)/s at field gradient pulse from 5.0 × 10(-2) to 3.0 × 10(-1)T/m, separated from other carbohydrates (glucose and fructose). Good linearity (r(2)=0.9999) was obtained between sucrose (0.5-20.0 g/L) and the resonance area of target glucopyranosyl-α-C1 proton normalised to that of cellobiose C1 proton (100.0 g/L, as an internal standard) in 1D sliced DOSY spectrum. The DOSY-qNMR method was successfully applied to quantify sucrose in orange juice (36.1 ± 0.5 g/L), pineapple juice (53.5 ± 1.1g/L) and a sports drink (24.7 ± 0.6g/L), in good agreement with the results obtained by an F-kit method.

  7. Application of diffusion ordered-1H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages.

    PubMed

    Cao, Ruge; Nonaka, Airi; Komura, Fusae; Matsui, Toshiro

    2015-03-15

    This work focuses on a quantitative analysis of sucrose using diffusion ordered-quantitative (1)H-nuclear magnetic resonance spectroscopy (DOSY-qNMR), where an analyte can be isolated from interference based on its characteristic diffusion coefficient (D) in gradient magnetic fields. The D value of sucrose in deuterium oxide at 30°C was 4.9 × 10(-10)m(2)/s at field gradient pulse from 5.0 × 10(-2) to 3.0 × 10(-1)T/m, separated from other carbohydrates (glucose and fructose). Good linearity (r(2)=0.9999) was obtained between sucrose (0.5-20.0 g/L) and the resonance area of target glucopyranosyl-α-C1 proton normalised to that of cellobiose C1 proton (100.0 g/L, as an internal standard) in 1D sliced DOSY spectrum. The DOSY-qNMR method was successfully applied to quantify sucrose in orange juice (36.1 ± 0.5 g/L), pineapple juice (53.5 ± 1.1g/L) and a sports drink (24.7 ± 0.6g/L), in good agreement with the results obtained by an F-kit method. PMID:25308635

  8. Alkaline β-fructofuranosidases of tuberous roots: Possible physiological function.

    PubMed

    Ricardo, C P

    1974-12-01

    Alkaline invertase of roots of carrot (Daucus carota L.) did not hydrolyze raffinose while the acid invertase from the same tissue showed with this sugar ca. 60% of the activity found with sucrose. The activity of the two invertases was inhibited by fructose to a different extent, the K i value being ca. 4×10(-2) M and 3×10(-1)M, respectively, for the alkaline and the acid invertases from the roots of both carrot and turnip (Brassica rapa L.). It is proposed that fructose inhibition of acid invertase is of no physiological significance but that, in contrast, hexoses might regulate the activity of alkaline invertase.Comparing several species and cultivars, it was found that the content of reducing sugars and the activity of alkaline invertase of mature tuberous roots showed a positive correlation. This indicates that alkaline invertase may participate in the regulation of the hexose level of the cell, as was previously suggested for sugar-cane. A scheme is presented which proposes a way of participation of alkaline invertase in such a regulation, assuming that this enzyme is located in the cytoplasm and acid invertase is membrane-bound and mainly located at the cell surface.

  9. Alkaline battery operational methodology

    DOEpatents

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  10. Gradient networks

    NASA Astrophysics Data System (ADS)

    Toroczkai, Zoltán; Kozma, Balázs; Bassler, Kevin E.; Hengartner, N. W.; Korniss, G.

    2008-04-01

    Gradient networks are defined (Toroczkai and Bassler 2004 Nature 428 716) as directed graphs formed by local gradients of a scalar field distributed on the nodes of a substrate network G. We present the derivation for some of the general properties of gradient graphs and give an exact expression for the in-degree distribution R(l) of the gradient network when the substrate is a binomial (Erd{\\;\\kern -0.10em \\raise -0.35ex \\{{^{^{\\prime\\prime}}}}\\kern -0.57em \\o} s-Rényi) random graph, G_{N,p} , and the scalars are independent identically distributed (i.i.d.) random variables. We show that in the limit N \\to \\infty, p \\to 0, z = pN = \\mbox{const} \\gg 1, R(l)\\propto l^{-1} for l < l_c = z , i.e., gradient networks become scale-free graphs up to a cut-off degree. This paper presents the detailed derivation of the results announced in Toroczkai and Bassler (2004 Nature 428 716).

  11. The large subunit determines catalytic specificity of barley sucrose:fructan 6-fructosyltransferase and fescue sucrose:sucrose 1-fructosyltransferase.

    PubMed

    Altenbach, Denise; Nüesch, Eveline; Meyer, Alain D; Boller, Thomas; Wiemken, Andres

    2004-06-01

    Plant fructosyltransferases are highly homologous in primary sequence and typically consist of two subunits but catalyze widely different reactions. Using functional expression in the yeast Pichia pastoris, we show that the substrate specificity of festuca sucrose:sucrose 1--beta-D-fructosyltransferase (1-SST) and barley sucrose:fructan 6--beta-D-fructosyltransferase (6-SFT) is entirely determined by the large subunit. Chimeric enzymes with the large subunit of festuca 1-SST (LSuB) and the small subunit of barley 6-SFT have the same catalytic specificity as the native festuca 1-SST and vice versa. If the LSuB is expressed alone, it does not yield a functionally active enzyme, indicating that the small subunit is nevertheless essential.

  12. A novel sucrose synthase pathway for sucrose degradation in cultured sycamore cells.

    PubMed

    Huber, S C; Akazawa, T

    1986-08-01

    Enzymes of sucrose degradation and glycolysis in cultured sycamore (Acer pseudoplatanus L.) cells were assayed and characterized in crude extracts and after partial purification, in an attempt to identify pathways for sucrose catabolism. Desalted cell extracts contained similar activities (20-40 nanomoles per milligram protein per minute) of sucrose synthase, neutral invertase, glucokinase, fructokinase, phosphofructokinase, and UDPglucose pyrophosphorylase (assayed with 2 micromolar pyrophosphate (PPi). PPi-linked phosphofructokinase activity was virtually dependent upon fructose 2,6-bisphosphate, and the maximum activity exceeded that of ATP-linked phosphofructokinase. Hexokinase activity, with glucose as substrate, was highly specific for ATP, whereas fructokinase activity was relatively nonspecific. At 1 millimolar nucleoside triphosphate, fructokinase activity decreased in the order: UTP > ATP > CTP > GTP. We propose two pathways for sucrose degradation. One involves invertase action, followed by classical glycolysis of hexose sugars, and the other is a novel pathway initiated by sucrose synthase. The K(m) for sucrose of sucrose synthase was severalfold lower than that of neutral invertase (15 versus 65 millimolar), which may determine carbon partitioning between the two pathways. The sucrose synthase pathway proposed involves cycling of uridylates and PPi. UDPglucose pyrophosphorylase, which is shown to be an effective ;PPi-scavenger,' would consume PPi and form UTP. The UTP could be then utilized in the UTP-linked fructokinase reaction, thereby forming UDP for sucrose synthase. The source of PPi is postulated to arise from the back reaction of PPi-linked phosphofructokinase. Sycamore cells contained a substantial endogenous pool of PPi (about 3 nanomoles per gram fresh weight, roughly 1/10 the amount of ATP in these cells), and sufficient fructose 2,6-bisphosphate (0.09 nanomole per gram fresh weight) to activate the PPi-linked phosphofructokinase. Possible

  13. Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter.

    PubMed

    Yeats, Trevor H; Sorek, Hagit; Wemmer, David E; Somerville, Chris R

    2016-05-01

    In order to understand factors controlling the synthesis and deposition of cellulose, we have studied the Arabidopsis (Arabidopsis thaliana) double mutant shaven3 shaven3-like1 (shv3svl1), which was shown previously to exhibit a marked cellulose deficiency. We discovered that exogenous sucrose (Suc) in growth medium greatly enhances the reduction in hypocotyl elongation and cellulose content of shv3svl1 This effect was specific to Suc and was not observed with other sugars or osmoticum. Live-cell imaging of fluorescently labeled cellulose synthase complexes revealed a slowing of cellulose synthase complexes in shv3svl1 compared with the wild type that is enhanced in a Suc-conditional manner. Solid-state nuclear magnetic resonance confirmed a cellulose deficiency of shv3svl1 but indicated that cellulose crystallinity was unaffected in the mutant. A genetic suppressor screen identified mutants of the plasma membrane Suc/H(+) symporter SUC1, indicating that the accumulation of Suc underlies the Suc-dependent enhancement of shv3svl1 phenotypes. While other cellulose-deficient mutants were not specifically sensitive to exogenous Suc, the feronia (fer) receptor kinase mutant partially phenocopied shv3svl1 and exhibited a similar Suc-conditional cellulose defect. We demonstrate that shv3svl1, like fer, exhibits a hyperpolarized plasma membrane H(+) gradient that likely underlies the enhanced accumulation of Suc via Suc/H(+) symporters. Enhanced intracellular Suc abundance appears to favor the partitioning of carbon to starch rather than cellulose in both mutants. We conclude that SHV3-like proteins may be involved in signaling during cell expansion that coordinates proton pumping and cellulose synthesis. PMID:27013021

  14. Isolation of Early and Late Endosomes by Density Gradient Centrifugation.

    PubMed

    de Araújo, Mariana E G; Lamberti, Giorgia; Huber, Lukas A

    2015-11-01

    Density gradient centrifugation is a common method for separating intracellular organelles. During centrifugation, organelles float or sediment until they reach their isopycnic position within the gradient. The density of an organelle depends on its content, size, shape, and the lipid:protein ratio. The degree of separation between different organelles will therefore be highly dependent on how different their isopycnic points are in a given buffer. Separation will also depend on the medium used to prepare the gradient, whether it is sucrose (the most common) or an alternative. Here we describe the use of both continuous and discontinuous (step) gradients to isolate endocytic organelles. PMID:26527762

  15. Contributions of sucrose synthase and invertase to the metabolism of sucrose in developing leaves: estimation by alternate substrate utilization

    SciTech Connect

    Schmalstig, J.G.; Hitz, W.D.

    1987-10-01

    The relative contributions of invertase and sucrose synthase to initial cleavage of phloem-imported sucrose was calculated for sink leaves of soybean (Glycine max L. Merr cv Wye) and sugar beet (Beta vulgaris L. monohybrid). Invertase from yeast hydrolyzed sucrose 4200 times faster than 1'-deoxy-1'-fluorosucrose (FS) while sucrose cleavage by sucrose synthase from developing soybean leaves proceeded only 3.6 times faster than cleavage of FS.(/sup 14/C)Sucrose and (/sup 14/C)FS, used as tracers of sucrose, were transported at identical rates to developing leaves through the phloem. The rate of label incorporation into insoluble products varied with leaf age from 3.4 to 8.0 times faster when (/sup 14/C)sucrose was supplied than when (/sup 14/C)FS was supplied. The discrimination in metabolism was related to enzymatic discriminations against FS to calculate the relative contributions of invertase and sucrose synthase to sucrose cleavage. In the youngest soybean leaves measured, 4% of final laminar length (FLL), all cleavage was by sucrose synthase. Invertase contribution to sucrose metabolism was 47% by 7.6% FLL, increased to 54% by 11% FLL, then declined to 42% for the remainder of the import phase. In sugar beet sink leaves at 30% FLL invertase contribution to sucrose metabolism was 58%.

  16. Functional analysis of sucrose phosphate synthase (SPS) and sucrose synthase (SS) in sugarcane (Saccharum) cultivars.

    PubMed

    Verma, A K; Upadhyay, S K; Verma, P C; Solomon, S; Singh, S B

    2011-03-01

    Sucrose phosphate synthase (SPS; EC 2.4.1.14) and sucrose synthase (SS; EC 2.4.1.13) are key enzymes in the synthesis and breakdown of sucrose in sugarcane. The activities of internodal SPS and SS, as well as transcript expression were determined using semi-quantitative RT-PCR at different developmental stages of high and low sucrose accumulating sugarcane cultivars. SPS activity and transcript expression was higher in mature internodes compared with immature internodes in all the studied cultivars. However, high sugar cultivars showed increased transcript expression and enzyme activity of SPS compared to low sugar cultivars at all developmental stages. SS activity was higher in immature internodes than in mature internodes in all cultivars; SS transcript expression showed a similar pattern. Our studies demonstrate that SPS activity was positively correlated with sucrose and negatively correlated with hexose sugars. However, SS activity was negatively correlated with sucrose and positively correlated with hexose sugars. The present study opens the possibility for improvement of sugarcane cultivars by increasing expression of the respective enzymes using transgene technology.

  17. Induction of Sucrose Utilization Genes from Bifidobacterium lactis by Sucrose and Raffinose

    PubMed Central

    Trindade, Marla I.; Abratt, Valerie R.; Reid, Sharon J.

    2003-01-01

    The probiotic organism Bifidobacterium lactis was isolated from a yoghurt starter culture with the aim of analyzing its use of carbohydrates for the development of prebiotics. A sucrose utilization gene cluster of B. lactis was identified by complementation of a gene library in Escherichia coli. Three genes, encoding a sucrose phosphorylase (ScrP), a GalR-LacI-type transcriptional regulator (ScrR), and a sucrose transporter (ScrT), were identified by sequence analysis. The scrP gene was expressed constitutively from its own promoter in E. coli grown in complete medium, and the strain hydrolyzed sucrose in a reaction that was dependent on the presence of phosphates. Primer extension experiments with scrP performed by using RNA isolated from B. lactis identified the transcriptional start site 102 bp upstream of the ATG start codon, immediately adjacent to a palindromic sequence resembling a regulator binding site. In B. lactis, total sucrase activity was induced by the presence of sucrose, raffinose, or oligofructose in the culture medium and was repressed by glucose. RNA analysis of the scrP, scrR, and scrT genes in B. lactis indicated that expression of these genes was influenced by transcriptional regulation and that all three genes were similarly induced by sucrose and raffinose and repressed by glucose. Analysis of the sucrase activities of deletion constructs in heterologous E. coli indicated that ScrR functions as a positive regulator. PMID:12513973

  18. Sham-feeding response of rats to Polycose and sucrose.

    PubMed

    Nissenbaum, J W; Sclafani, A

    1987-01-01

    Adult female rats were fitted with gastric fistulas and maintained at 85% of their ad lib body weight. Their real-feeding (fistula closed) and sham-feeding (fistula open) responses to polysaccharide (Polycose) and sucrose solutions were measured during 30 min/day one-bottle tests. The rats consumed similar amounts of a 1% Polycose solution during real- and sham-feeding tests, but their sham-intakes of 4%, 16% and 32% Polycose solutions greatly exceeded their real-intakes of these solutions. Similar results were obtained with sucrose solutions. The rats sham-fed more Polycose than sucrose at the 1% and 4% concentrations, while their sham-intakes of the 16% and 32% Polycose and sucrose solutions were comparable. In subsequent two-solution sham-feeding tests, the rats preferred 1% Polycose to 1% sucrose, but preferred sucrose to Polycose at 4%, 16% and 32% concentrations. These preference results indicate that rats find Polycose more palatable than sucrose at low concentrations, but sucrose more palatable at high concentrations. In addition, the findings that the rats preferred 4% sucrose to 4% Polycose in the two-bottle test, but sham-fed more 4% Polycose than 4% sucrose in the one-bottle tests, suggest that sucrose is more "orally-satiating" than is Polycose. These results provide further evidence for qualitative differences in the tastes of sucrose and polysaccharide. They also indicate that the amount of solution sham-fed does not necessarily reflect the palatability of the solution.

  19. Translocation of labelled sucrose: A student exercise

    SciTech Connect

    Reiss, C. )

    1990-05-01

    Photosynthetic carbohydrates from the leaves are exported through the phloem to growing tips, roots, flowers and fruits. If sucrose labelled with {sup 14}C is applied to the leaves of bean plants, the pathway for sugar movement may be readily observed by autoradiography. Students apply the labelled sucrose during class time and return the next day to press their plants. During the next class, the pressed and dried plants are placed against X-ray film and left in the dark for four weeks. the film is then developed, examined for presence of label and compared to the pressed plants. Source to sink movement is clearly illustrated and information about the mechanism of phloem transport and loading is gained through experimental treatments, which include blocking the phloem pathway and inhibiting energy production.

  20. Regulation of the paracellular Na+ and Cl- conductances by the NaCl-generated osmotic gradient in a manner dependent on the direction of osmotic gradients.

    PubMed

    Tokuda, Shinsaku; Niisato, Naomi; Nakajima, Ken-Ichi; Marunaka, Yoshinori

    2008-02-01

    In the present study, we investigated the effect of osmolality on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)). An osmotic gradient generated by NaCl with relatively apical hypertonicity (NaCl-absorption-direction) induced a large increase in the G(Na) associated with a small increase in the G(Cl), whereas an osmotic gradient generated by NaCl with relatively basolateral hypertonicity (NaCl-secretion-direction) induced small increases in the G(Na) and the G(Cl). These increases in the Gp caused by NaCl-generated osmotic gradients were diminished by the application of sucrose canceling the NaCl-generated osmotic gradient. The osmotic gradient generated by apical [corrected] application of sucrose without any NaCl gradients had little effects on the Gp. However, this apical [corrected] application of sucrose produced a precondition drastically quickening the time course of the action of the NaCl-generated osmotic gradient on the Gp. Further, we found that application of the basolateral hypotonicity generated by reduction of NaCl concentration shifted the localization of claudin-1 to the apical from the lateral [corrected] side. These results indicate that the osmotic gradient regulates the paracellular ion conductive pathway of tight junctions via a mechanism dependent on the direction of NaCl gradients associated with a shift of claudin-1 localization to the apical side in renal A6 epithelial cells. PMID:18068115

  1. Withanolides and Sucrose Esters from Physalis neomexicana.

    PubMed

    Cao, Cong-Mei; Wu, Xiaoqing; Kindscher, Kelly; Xu, Liang; Timmermann, Barbara N

    2015-10-23

    Four withanolides (1-4) and two sucrose esters (5, 6) were isolated from the aerial parts of Physalis neomexicana. The structures of 1-6 were elucidated through a variety of spectroscopic techniques. Cytotoxicity studies of the isolates revealed that 2 inhibited human breast cancer cell lines (MDA-MB-231 and MCF-7) with IC50 values of 1.7 and 6.3 μM, respectively.

  2. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy. PMID:26404834

  3. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

  4. Role of Sucrose in Gamma-irradiated Chrysanthemum Cut Flowers.

    PubMed

    Nakahara, K; Kikuchi, O K; Todoriki, S; Hosoda, H; Hayashi, T

    1998-01-01

    Vase solution containing 2% sucrose prevented the deterioration of chrysanthemum (Dendranthema grandiflorum Kitamura) cut flowers induced by gamma-rays at 750 Gy. Glucose, fructose, and sucrose in florets and leaves of irradiated chrysanthemums decreased more rapidly than those of unirradiated ones, when the cut chrysanthemums were held in a vase solution without sucrose. The sugar contents of florets and leaves and the respiratory rate of irradiated chrysanthemums held with sucrose remained at higher levels than those of unirradiated ones. Incorporation of (14)C from [(14)C]sucrose into CO2 was increased by irradiation. Incorporation of [α-(32)P]dTTP into trichloroacetic acid (TCA) insoluble substances in florets was increased by irradiation and by exogenous sucrose supply. These results suggest that sucrose in a vase solution was used as a respiratory substrate and facilitated the repair of radiation-induced damage, resulting in the extension of longevity of irradiated chrysanthemums.

  5. Acid and Alkaline Invertases in Suspension Cultures of Sugar Beet Cells

    PubMed Central

    Masuda, Hiroshi; Takahashi, Toshimasa; Sugawara, Shiro

    1988-01-01

    Alkaline invertase was induced during the initiation of suspension cultures of single cells from leaf explants of sugar beets in Murashige-Skoog liquid medium which contained benzyladenine. This activity was barely detectable in the leaves themselves. In suspension cultures, the presence of both acid and alkaline invertases was detected; alkaline invertase was only present in the cytoplasm of the cultured cells, whereas acid invertase was present in the cytoplasm and cell walls, and was also detected in the culture medium. The cell wall contained at least three types of acid invertase; two of these activities were solubilized by saline (saline-released) and EDTA (EDTA-released), respectively, and the third remained tightly associated with the cell wall. Saline-released and EDTA-released invertases from the cell wall showed the significant differences in their properties: the saline-released enzyme had the highest affinity for sucrose among the invertases tested, and was easily bound to cell walls, to DNA, and to a cation exchanger, unlike the EDTA-released enzyme. Sucrose is the source of carbon for plant cells in suspension culture and is probably degraded in the cell wall by the saline-released invertase, which had the highest activity and the highest affinity for sucrose. Hexose products of this degradation would be transported to cytoplasm. Soluble invertase, EDTA-released invertase from the cell wall, and one of two extracellular invertases behaved similarly upon chromatography on DEAE-cellulose. They had similar activity profiles with changing pH, and similar Km values for sucrose. Thus it appears that they are identical. Two extracellular invertases found in the growth medium of the suspension cultures were probably identical with those in the soluble fraction of callus and seedlings of sugar beets, because they showed similar behaviors during chromatography on DEAE-cellulose, and had similar activity profiles with changing pH and Km values for sucrose. PMID

  6. Behavioral economics of concurrent ethanol-sucrose and sucrose reinforcement in the rat: effects of altering variable-ratio requirements.

    PubMed Central

    Petry, N M; Heyman, G M

    1995-01-01

    These experiments examined the own-price and cross-price elasticities of a drug (ethanol mixed with 10% sucrose) and a nondrug (10% sucrose) reinforcer. Rats were presented with ethanol-sucrose and sucrose, both available on concurrent independent variable-ratio (VR) 8 schedules of reinforcement. In Experiment 1, the variable ratio for the ethanol mix was systematically raised to 10, 12, 14, 16, 20, and 30, while the variable ratio for sucrose remained at 8. Five of the 6 rats increased ethanol-reinforced responding at some of the increments and defended baseline levels of ethanol intake. However, the rats eventually ceased ethanol-reinforced responding at the highest variable ratios. Sucrose-reinforced responding was not systematically affected by the changes in variable ratio for ethanol mix. In Experiment 2, the variable ratio for sucrose was systematically increased while the ethanol-sucrose response requirement remained constant. The rats decreased sucrose-reinforced responding and increased ethanol-sucrose-reinforced responding, resulting in a two- to 10-fold increase in ethanol intake. Experiment 3 examined the substitutability of qualitatively identical reinforcers: 10% sucrose versus 10% sucrose. Increases in variable-ratio requirements at the preferred lever resulted in a switch in lever preference. Experiment 4 examined whether 10% ethanol mix substituted for 5% ethanol mix, with increasing variable-ratio requirements of the 5% ethanol. All rats eventually responded predominantly for the 10% ethanol mix, but total amount of ethanol consumed per session did not systematically change. In Experiment 5, the variable-ratio requirements for both ethanol and sucrose were simultaneously raised to VR 120; 7 of 8 rats increased ethanol-reinforced responding while decreasing sucrose-reinforced responding. These data suggest that, within this ethanol-induction procedure and within certain parameters, demand for ethanol-sucrose was relatively inelastic, and sucrose

  7. Sucrose secreted by the engineered cyanobacterium and its fermentability

    NASA Astrophysics Data System (ADS)

    Duan, Yangkai; Luo, Quan; Liang, Feiyan; Lu, Xuefeng

    2016-10-01

    The unicellular cyanobacterium, Synechococcus elongatus PCC 7942 (Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constructed. The overexpression of the native sps (encoding a natively fused protein of sucrose phosphate synthase SPS and sucrose phosphate phosphatase SPP) in Syn7942 wild type caused a 93% improvement of sucrose productivity. The strain FL130 co-overexpressing sps and cscB (encoding a sucrose transporter) exhibited a 74% higher extracellular sucrose production than that overexpressing cscB only. Both results showed the significant improvement of sucrose productivity by the double functional protein SPS-SPP. Afterwards, FL130 was cultivated under a modified condition, and the cell-free culture medium containing 1.5 g L-1 sucrose was pre-treated with an acid hydrolysis technique. Cultivated with the neutralized hydrolysates as the starting media, two widely used microorganisms, Escherichia coli and Saccharomyces cerevisiae, showed a comparable growth with that in the control media supplemented with glucose. These results clearly demonstrated that the cell-free culture of sucrose-secreting cyanobacteria can be applied as starting media in microbial cultivation.

  8. Sucrose and Warmth for Analgesia in Healthy Newborns: An RCT

    PubMed Central

    Garza, Elizabeth; Zageris, Danielle; Heilman, Keri J.; Porges, Stephen W.

    2015-01-01

    BACKGROUND AND OBJECTIVE: Increasing data suggest that neonatal pain has long-term consequences. Nonpharmacologic techniques (sucrose taste, pacifier suckling, breastfeeding) are effective and now widely used to combat minor neonatal pain. This study examined the analgesic effect of sucrose combined with radiant warmth compared with the taste of sucrose alone during a painful procedure in healthy full-term newborns. METHODS: A randomized, controlled trial included 29 healthy, full-term newborns born at the University of Chicago Hospital. Both groups of infants were given 1.0 mL of 25% sucrose solution 2 minutes before the vaccination, and 1 group additionally was given radiant warmth from an infant warmer before the vaccination. We assessed pain by comparing differences in cry, grimace, heart rate variability (ie, respiratory sinus arrhythmia), and heart rate between the groups. RESULTS: The sucrose plus warmer group cried and grimaced for 50% less time after the vaccination than the sucrose alone group (P < .05, respectively). The sucrose plus warmer group had lower heart rate and heart rate variability (ie, respiratory sinus arrhythmia) responses compared with the sucrose alone group (P < .01), reflecting a greater ability to physiologically regulate in response to the painful vaccination. CONCLUSIONS: The combination of sucrose and radiant warmth is an effective analgesic in newborns and reduces pain better than sucrose alone. The ready availability of this practical nonpharmacologic technique has the potential to reduce the burden of newborn pain. PMID:25687147

  9. A detailed analysis of sucrose drinking in the rat.

    PubMed

    Spector, A C; Smith, J C

    1984-07-01

    The present report represents an initial attempt to examine and quantify the eating and drinking patterns of rats presented with water, laboratory chow, and sucrose solution for 23 hours. The concentration of the sucrose solution was systematically increased (0.10 M, 0.25 M, 0.5 M, 1.0 M) with a single concentration being presented to rats in four-day blocks. As has been previously shown, total intake (ml) of sucrose solution increased with concentration to a peak at 0.25 M and then decreased with further rises in concentration. Calories consumed from sucrose monotonically increased with concentration, reaching a maximum at 0.50 M. As calories consumed from sucrose increased with rising concentration, chow intake monotonically decreased. This compensatory decrease in chow intake was primarily attributable to decreases in nighttime chow consumption when the concentration of sucrose available was less than or equal to 0.25 M; when the concentration was greater than 0.25 M, further reductions in chow intake occurred during the day. Moreover, the decrease in chow intake was due solely to a reduction in the number of chow bouts. As the concentration of sucrose increased, the day-to-night ratio of sucrose intake approached unity. Bout volume increased with concentration to a broad peak spanning 0.25-0.5 M, and then decreased with 1.0 M. Bout duration changed with sucrose concentration such that the bout drinking rate (ml/min) was seen to monotonically increase, reaching a stable maximum at 0.5 M. Since the caloric intake per sucrose bout progressively increased with each rise in concentration, the asymptotic portion of the curve describing calories consumed from sucrose was attributable to alterations in sucrose bout number and not sucrose bout size.

  10. Evolution of plant sucrose uptake transporters.

    PubMed

    Reinders, Anke; Sivitz, Alicia B; Ward, John M

    2012-01-01

    In angiosperms, sucrose uptake transporters (SUTs) have important functions especially in vascular tissue. Here we explore the evolutionary origins of SUTs by analysis of angiosperm SUTs and homologous transporters in a vascular early land plant, Selaginella moellendorffii, and a non-vascular plant, the bryophyte Physcomitrella patens, the charophyte algae Chlorokybus atmosphyticus, several red algae and fission yeast, Schizosaccharomyces pombe. Plant SUTs cluster into three types by phylogenetic analysis. Previous studies using angiosperms had shown that types I and II are localized to the plasma membrane while type III SUTs are associated with vacuolar membrane. SUT homologs were not found in the chlorophyte algae Chlamydomonas reinhardtii and Volvox carterii. However, the characean algae Chlorokybus atmosphyticus contains a SUT homolog (CaSUT1) and phylogenetic analysis indicated that it is basal to all other streptophyte SUTs analyzed. SUTs are present in both red algae and S. pombe but they are less related to plant SUTs than CaSUT1. Both Selaginella and Physcomitrella encode type II and III SUTs suggesting that both plasma membrane and vacuolar sucrose transporter activities were present in early land plants. It is likely that SUT transporters are important for scavenging sucrose from the environment and intracellular compartments in charophyte and non-vascular plants. Type I SUTs were only found in eudicots and we conclude that they evolved from type III SUTs, possibly through loss of a vacuolar targeting sequence. Eudicots utilize type I SUTs for phloem (vascular tissue) loading while monocots use type II SUTs for phloem loading. We show that HvSUT1 from barley, a type II SUT, reverted the growth defect of the Arabidopsis atsuc2 (type I) mutant. This indicates that type I and II SUTs evolved similar (and interchangeable) phloem loading transporter capabilities independently. PMID:22639641

  11. Alkaline galvanic cell

    SciTech Connect

    Inoue, T.; Maeda, Y.; Momose, K.; Wakahata, T.

    1983-10-04

    An alkaline galvanic cell is disclosed including a container serving for a cathode terminal, a sealing plate in the form of a layered clad plate serving for an anode terminal to be fitted into the container, and an insulating packing provided between the sealing plate and container for sealing the cell upon assembly. The cell is provided with a layer of epoxy adduct polyamide amine having amine valence in the range of 50 to 400 and disposed between the innermost copper layer of the sealing plate arranged to be readily amalgamated and the insulating packing so as to serve as a sealing agent or liquid leakage suppression agent.

  12. Kinetics of sucrose crystallization in whey protein films.

    PubMed

    Dangaran, Kirsten L; Krochta, John M

    2006-09-20

    The kinetics of sucrose crystallization in whey protein isolate (WPI) films was studied at 25 degrees C in four different relative humidity environments: 23, 33, 44, and 53%. The effects of protein matrix, crystallization inhibitors, and storage environment on the rate constants of sucrose crystallization were determined using the Avrami model of crystallization. It was found that a cross-linked, denatured whey protein (WP) matrix more effectively hindered sucrose crystallization than a protein matrix of native WP. The crystallization inhibitors tested were lactose, raffinose, modified starch (Purity 69), and polyvinylpyrrolidone (Plasdone C15). Raffinose and modified starch were determined to be the more effective inhibitors of sucrose crystallization. At lower relative humidities (23, 33, and 44%), the cross-linked protein matrix played a more important role in sucrose crystallization than the inhibitors. As relative humidity increased (53%), the crystallization inhibitors were more central to controlling sucrose crystallization in WPI films.

  13. Effect of dietary carbohydrate and phenotype on sucrase, maltase, lactase, and alkaline phosphatase specific activity in SHR/N-cp rat.

    PubMed

    Wiesenfeld, P; Baldwin, J; Szepesi, B; Michaelis, O E

    1993-03-01

    The obese spontaneous hypertensive rat/NIH-corpulent (SHR/N-cp) rat exhibits some of the metabolic and pathologic alterations associated with non-insulin-dependent diabetes mellitus and hypertension. The current study was conducted to investigate the influence of phenotype (ob versus In) and source of dietary carbohydrate (sucrose versus starch) on intestinal sucrase, maltase, lactase, and alkaline phosphatase activity in SHR/N-cp rats. For 3 months, lean and obese male SHR/N-cp rats were fed isocaloric diets containing as the sole source of carbohydrate either 54% cooked corn starch or sucrose. Serum and urine markers for diabetes were observed in obese rats. Wet weight and length of intestines were significantly increased in obese rats compared with lean littermates. Among the intestinal enzymes measured, statistical tests confirmed that sucrase activity was significantly increased (P < 0.01) by both phenotype (ob > In) and feeding a sucrose diet. Diet alone (sucrose > starch) significantly increased (P < 0.05) maltase activity in obese rats, but had no effect on lean rats. Lactase activity was significantly higher (P < 0.05) in obese sucrose-fed rats compared with obese starch-fed and/or lean littermates. Statistical tests revealed that intestinal alkaline phosphatase activity was significantly altered (P < 0.05) by both phenotype and diet. Intestinal alkaline phosphatase was higher in starch-fed lean rats compared with lean littermates fed sucrose and to starch or sucrose-fed obese rats. These results are not indicative of a simple, nonspecific increase in intestinal enzyme activity, since the effects observed in intestinal alkaline phosphatase contrast the effects observed in intestinal sucrase, maltase, and lactase activity. These results indicate that both phenotype and diet alter structural and enzymatic intestinal activities of SHR/N-cp rats. Distinct variations in the observed intestinal enzymatic activities suggest that these enzymes are under the

  14. Alkaline fuel cells applications

    NASA Astrophysics Data System (ADS)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  15. Effect of salt on the response of birds to sucrose

    USGS Publications Warehouse

    Rogers, J.G.; Maller, O.

    1973-01-01

    The preference of male red-winged blackbirds for solutions of sucrose and sucrose with 0.03 M sodium chloride was tested, using a two-bottle choice test. Preliminary experiments demonstrated that the birds were indifferent to 0.03 M NaCl in water. Both control and experimental animals exhibited indifference to the solutions at the lowest concentration and aversion at the highest. The data suggest that the added sodium chloride makes the sucrose stimulus more discriminable.

  16. Sucrose metabolism in halotolerant methanotroph Methylomicrobium alcaliphilum 20Z.

    PubMed

    But, Sergey Y; Khmelenina, Valentina N; Reshetnikov, Alexander S; Mustakhimov, Ildar I; Kalyuzhnaya, Marina G; Trotsenko, Yuri A

    2015-04-01

    Sucrose accumulation has been observed in some methylotrophic bacteria utilizing methane, methanol, or methylated amines as a carbon and energy source. In this work, we have investigated the biochemical pathways for sucrose metabolism in the model halotolerant methanotroph Methylomicrobium alcaliphilum 20Z. The genes encoding sucrose-phosphate synthase (Sps), sucrose-phosphate phosphatase (Spp), fructokinase (FruK), and amylosucrase (Ams) were co-transcribed and displayed similar expression levels. Functional Spp and Ams were purified after heterologous expression in Escherichia coli. Recombinant Spp exhibited high affinity for sucrose-6-phosphate and stayed active at very high levels of sucrose (K i  = 1.0 ± 0.6 M). The recombinant amylosucrase obeyed the classical Michaelis-Menten kinetics in the reactions of sucrose hydrolysis and transglycosylation. As a result, the complete metabolic network for sucrose biosynthesis and re-utilization in the non-phototrophic organism was reconstructed for the first time. Comparative genomic studies revealed analogous gene clusters in various Proteobacteria, thus indicating that the ability to produce and metabolize sucrose is widespread among prokaryotes.

  17. Sucrose and KF quenching system for solution phase parallel synthesis.

    PubMed

    Chavan, Sunil; Watpade, Rahul; Toche, Raghunath

    2016-01-01

    The KF, sucrose (table sugar) exploited as quenching system in solution phase parallel synthesis. Excess of electrophiles were covalently trapped with hydroxyl functionality of sucrose and due to polar nature of sucrose derivative was solubilize in water. Potassium fluoride used to convert various excess electrophilic reagents such as acid chlorides, sulfonyl chlorides, isocyanates to corresponding fluorides, which are less susceptible for hydrolysis and subsequently sucrose traps these fluorides and dissolves them in water thus removing them from reaction mixture. Various excess electrophilic reagents such as acid chlorides, sulfonyl chlorides, and isocyanates were quenched successfully to give pure products in excellent yields. PMID:27462506

  18. Sucrose metabolism in halotolerant methanotroph Methylomicrobium alcaliphilum 20Z.

    PubMed

    But, Sergey Y; Khmelenina, Valentina N; Reshetnikov, Alexander S; Mustakhimov, Ildar I; Kalyuzhnaya, Marina G; Trotsenko, Yuri A

    2015-04-01

    Sucrose accumulation has been observed in some methylotrophic bacteria utilizing methane, methanol, or methylated amines as a carbon and energy source. In this work, we have investigated the biochemical pathways for sucrose metabolism in the model halotolerant methanotroph Methylomicrobium alcaliphilum 20Z. The genes encoding sucrose-phosphate synthase (Sps), sucrose-phosphate phosphatase (Spp), fructokinase (FruK), and amylosucrase (Ams) were co-transcribed and displayed similar expression levels. Functional Spp and Ams were purified after heterologous expression in Escherichia coli. Recombinant Spp exhibited high affinity for sucrose-6-phosphate and stayed active at very high levels of sucrose (K i  = 1.0 ± 0.6 M). The recombinant amylosucrase obeyed the classical Michaelis-Menten kinetics in the reactions of sucrose hydrolysis and transglycosylation. As a result, the complete metabolic network for sucrose biosynthesis and re-utilization in the non-phototrophic organism was reconstructed for the first time. Comparative genomic studies revealed analogous gene clusters in various Proteobacteria, thus indicating that the ability to produce and metabolize sucrose is widespread among prokaryotes. PMID:25577257

  19. Two-Component Self-Diffusion in Solutions: Trehalose and Sucrose in Water

    NASA Astrophysics Data System (ADS)

    Feick, E. J.; von Meerwall, E. D.; Ekdawi, N.; de Pablo, J.

    2001-03-01

    Trehalose is now recognized as a superior substitute for sucrose in solution as a cryoprotectant, for preserving organs destined for transplantation. To explore some aspects of this superiority, we have used the proton NMR pulsed-gradient spin-echo method at T = 30, 50, and 85 deg. C to study the self-diffusion of solvent and solute in aqueous solutions of these molecules as function of their concentration, c. We find that both solute molecules diffuse substantially more slowly than water at the same c and T; that addition of water accelerates solute diffusion more rapidly than that of water; and that while at a given c and T water diffusion is insensitive to solute identity, trehalose diffusion is somewhat slower than sucrose diffusion, an effect which reaches a factor near two at the highest c. The results of our extensive MC and MD molecular simulations of diffusion in sucrose solutions agree quantitatively with our experimental findings at corresponding c. Free-volume theory is also employed to explore the cooperative interactions between solvent and solutes, and to guide the interpretation of both experiment and simulation.

  20. Functional characterization of sucrose phosphorylase and scrR, a regulator of sucrose metabolism in Lactobacillus reuteri.

    PubMed

    Teixeira, Januana S; Abdi, Reihaneh; Su, Marcia Shu-Wei; Schwab, Clarissa; Gänzle, Michael G

    2013-12-01

    Lactobacillus reuteri harbours alternative enzymes for sucrose metabolism, sucrose phosphorylase, fructansucrases, and glucansucrases. Sucrose phosphorylase and fructansucrases additionally contribute to raffinose metabolism. Glucansucrases and fructansucrases produce exopolysaccharides as alternative to sucrose hydrolysis. L. reuteri LTH5448 expresses a levansucrase (ftfA) and sucrose phosphorylase (scrP), both are inducible by sucrose. This study determined the contribution of scrP to sucrose and raffinose metabolism in L. reuteri LTH5448, and elucidated the role of scrR in regulation sucrose metabolism. Disruption of scrP and scrR was achieved by double crossover mutagenesis. L. reuteri LTH5448, LTH5448ΔscrP and LTH5448ΔscrR were characterized with respect to growth and metabolite formation with glucose, sucrose, or raffinose as sole carbon source. Inactivation of scrR led to constitutive transcription of scrP and ftfA, demonstrating that scrR is negative regulator. L. reuteri LTH5448 and the LTH5448ΔscrP or LTH5448ΔscrR mutant strains did not differ with respect to glucose, sucrose or raffinose utilization. However, L. reuteri LTH5448ΔscrP produced more levan, indicating that the lack of sucrose phosphorylase is compensated by an increased metabolic flux through levansucrase. In conclusion, the presence of alternate pathways for sucrose and raffinose metabolism and their regulation indicate that these substrates, which are abundant in plants, are preferred carbohydrate sources for L. reuteri. PMID:24010626

  1. Sucrose Phosphate Synthase and Acid Invertase as Determinants of Sucrose Concentration in Developing Muskmelon (Cucumis melo L.) Fruits 1

    PubMed Central

    Hubbard, Natalie L.; Huber, Steven C.; Pharr, D. Mason

    1989-01-01

    Fruits of orange-fleshed and green-fleshed muskmelon (Cucumis melo L.) were harvested at different times throughout development to evaluate changes in metabolism which lead to sucrose accumulation, and to determine the basis of differences in fruit sucrose accumulation among genotypes. Concentrations of sucrose, raffinose saccharides, hexoses and starch, as well as activities of the sucrose metabolizing enzymes sucrose phosphate synthase (SPS) (EC 2.4.1.14), sucrose synthase (EC 2.4.1.13), and acid and neutral invertases (EC 3.2.1.26) were measured. Sucrose synthase and neutral invertase activities were relatively low (1.7 ± 0.3 micromole per hour per gram fresh weight and 2.2 ± 0.2, respectively) and changed little throughout fruit development. Acid invertase activity decreased during fruit development, (from as high as 40 micromoles per hour per gram fresh weight) in unripe fruit, to undetectable activity in mature, ripened fruits, while SPS activity in the fruit increased (from 7 micromoles per hour per gram fresh weight) to as high as 32 micromoles per hour per gram fresh weight. Genotypes which accumulated different amounts of sucrose had similar acid invertase activity but differed in SPS activity. Our results indicate that both acid invertase and SPS are determinants of sucrose accumulation in melon fruit. However, the decline in acid invertase appears to be a normal function of fruit maturation, and is not the primary factor which determines sucrose accumulation. Rather, the capacity for sucrose synthesis, reflected in the activity of SPS, appears to determine sucrose accumulation, which is an important component of fruit quality. PMID:16667212

  2. On gradient field theories: gradient magnetostatics and gradient elasticity

    NASA Astrophysics Data System (ADS)

    Lazar, Markus

    2014-09-01

    In this work, the fundamentals of gradient field theories are presented and reviewed. In particular, the theories of gradient magnetostatics and gradient elasticity are investigated and compared. For gradient magnetostatics, non-singular expressions for the magnetic vector gauge potential, the Biot-Savart law, the Lorentz force and the mutual interaction energy of two electric current loops are derived and discussed. For gradient elasticity, non-singular forms of all dislocation key formulas (Burgers equation, Mura equation, Peach-Koehler stress equation, Peach-Koehler force equation, and mutual interaction energy of two dislocation loops) are presented. In addition, similarities between an electric current loop and a dislocation loop are pointed out. The obtained fields for both gradient theories are non-singular due to a straightforward and self-consistent regularization.

  3. Sucrose transport and phloem unloading in stem of Vicia faba: possible involvement of a sucrose carrier and osmotic regulation

    SciTech Connect

    Aloni, B.; Wyse, R.E.; Griffith, S.

    1986-06-01

    After pulse labeling of a source leaf with /sup 14/CO/sub 2/, stem sections of Vicia faba plants were cut and the efflux characteristics of /sup 14/C-labeled sugars into various buffered solutions were determined. Radiolabeled sucrose was shown to remain localized in the phloem and adjacent phloem parenchyma tissues after a 2-hour chase. Therefore, sucrose leakage from stem segments prepared following a 75-minute chase period was assumed to be characteristic of phloem unloading. The efflux of /sup 14/C assimilates from the phloem was enhanced by 1 millimolar p-chloromercuribenzene sulfonic acid (PCMBS) and by 5 micromolar carbonyl cyanide m-chlorophenly hydrazone (CCCP). However, PCMBS inhibited and CCCP enhanced general leakage of nonradioactive sugars from the stem segments. Sucrose at concentrations of 50 millimolar in the free space increased efflux of (/sup 14/C)sucrose, presumably through an exchange mechanism. This exchange was inhibited by PCMBS and abolished by 0.2 molar mannitol. Increasing the osmotic concentration of the efflux medium with mannitol reduced (/sup 14/C)sucrose efflux. However, this inhibition seems not to be specific to sucrose unloading since leakage of total sugars, nonlabeled sucrose, glucose, and amino acids from the bulk of the tissue was reduced in a similar manner. The data suggest that phloem unloading in cut stem segments is consistent with passive efflux of sucrose from the phloem to the apoplast and that sucrose exchange via a membrane carrier may be involved.

  4. Silica in alkaline brines

    USGS Publications Warehouse

    Jones, B.F.; Rettig, S.L.; Eugster, H.P.

    1967-01-01

    Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO 2 can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO2 with concentration of Na and total CO2 support this interpretation. Addition of moredilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.

  5. Bifunctional alkaline oxygen electrodes

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

  6. Compartmentation of sucrose during radial transfer in mature sorghum culm

    PubMed Central

    Tarpley, Lee; Vietor, Donald M

    2007-01-01

    Background The sucrose that accumulates in the culm of sorghum (Sorghum bicolor (L.) Moench) and other large tropical andropogonoid grasses can be of commercial value, and can buffer assimilate supply during development. Previous study conducted with intact plants showed that sucrose can be radially transferred to the intracellular compartment of mature ripening sorghum internode without being hydrolysed. In this study, culm-infused radiolabelled sucrose was traced between cellular compartments and among related metabolites to determine if the compartmental path of sucrose during radial transfer in culm tissue was symplasmic or included an apoplasmic step. This transfer path was evaluated for elongating and ripening culm tissue of intact plants of two semidwarf grain sorghums. The metabolic path in elongating internode tissue was also evaluated. Results On the day after culm infusion of the tracer sucrose, the specific radioactivity of sucrose recovered from the intracellular compartment of growing axillary-branch tissue was greater (nearly twice) than that in the free space, indicating that sucrose was preferentially transferred through symplasmic routes. In contrast, the sucrose specific radioactivity in the intracellular compartment of the mature (ripening) culm tissue was probably less (about 3/4's) than that in free space indicating that sucrose was preferentially transferred through routes that included an apoplasmic step. In growing internodes of the axillary branch of sorghum, the tritium label initially provided in the fructose moiety of sucrose molecules was largely (81%) recovered in the fructose moiety, indicating that a large portion of sucrose molecules is not hydrolysed and resynthesized during radial transfer. Conclusion During radial transfer of sucrose in ripening internodes of intact sorghum plants, much of the sucrose is transferred intact (without hydrolysis and resynthesis) and primarily through a path that includes an apoplasmic step. In

  7. Fluoroquinolone resistance of Serratia marcescens: sucrose, salicylate, temperature, and pH induction of phenotypic resistance.

    PubMed

    Begic, Sanela; Worobec, Elizabeth A

    2007-11-01

    Serratia marcescens is a nosocomial agent with a natural resistance to a broad spectrum of antibiotics, making the treatment of its infections very challenging. This study examines the influence of salicylate, sucrose, temperature, and pH variability on membrane permeability and susceptibility of S. marcescens to norfloxacin (hydrophilic fluoroquinolone) and nalidixic acid (hydrophobic quinolone). Resistance of wild-type S. marcescens UOC-67 (ATCC 13880) to norfloxacin and nalidixic acid was assessed by minimal inhibitory concentration (MIC) assays after growth in the presence of various concentrations of sucrose and salicylate and different temperatures and pH values. Norfloxacin and nalidixic acid accumulation was determined in the absence and presence of (i) carbonyl cyanide m-chlorophenylhydrazone (CCCP), a proton-motive-force collapser, and (ii) Phe-Arg beta-naphthylamide (PAbetaN), an efflux pump inhibitor. Accumulation of norfloxacin decreased when S. marcescens was grown in high concentrations of salicylate (8 mmol/L) and sucrose (10% m/v), at high temperature (42 degrees C), and at pH 6, and it was restored in the presence of CCCP because of the collapse of proton-gradient-dependent efflux in S. marcescens. Although nalidixic acid accumulation was observed, it was not affected by salicylate, sucrose, pH, or temperature changes. In the absence of PAbetaN, and either in the presence or absence of CCCP, a plateau was reached in the nalidixic acid accumulation for all environmental conditions. With the addition of 20 mg/L PAbetaN nalidixic acid accumulation is restored for all environmental conditions, suggesting that this quinolone is recognized by a yet to be identified S. marcescens pump that does not use proton motive force as its energy source.

  8. Sucrolytic Enzyme Activities in Cotyledons of the Faba Bean (Developmental Changes and Purification of Alkaline Invertase).

    PubMed Central

    Ross, H. A.; McRae, D.; Davies, H. V.

    1996-01-01

    In terms of maximum extractable catalytic activity, sucrose synthase is the predominant sucrolytic enzyme in developing cotyledons of faba bean (Vicia faba L.). Although acid invertase activity is extremely low, there is significant activity of alkaline invertase, the majority of which is extractable only with high concentrations of NaCl. Calculations of potential activity in vivo indicate that alkaline invertase is the predominant sucrolytic enzyme from 50 days after anthesis onward. However, at almost all stages of cotyledon development analyzed, the maximum extractable catalytic activities of both enzymes is in excess of the actual rate of starch deposition. Two forms of alkaline invertase were identified in developing cotyledons. The major form has been purified to homogeneity, and antibodies have been raised against it. The native protein has a molecular mass of about 238 [plus or minus] 4.5 kD. It is apparently a homotetramer (subunit molecular mass 53.4 [plus or minus] 0.9 kD). The enzyme has a pH optimum of 7.4, an isoelectric point of 5.2, and a Km[sucrose] of 10 mM and is inhibited by Tris (50% inhibition at 5 mM) and fructose (30% inhibition at 10 mM). Bean alkaline invertase is a [beta]-fructofuranosidase with no significant activity against raffinose, stachyose, trehalose, maltose, or lactose. PMID:12226291

  9. Functionality of Inulin as a Sucrose Replacer in Cookie Baking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inulin was evaluated as a sucrose replacer for healthy cookie production with benefits of low glycemic impact and prebiotic soluble fiber. Sucrose (as a reference) and three inulin products of different concentrations (as soluble fibers) were used to explore the effects of sugar-replacer type on so...

  10. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sucrose fatty acid esters. 172.859 Section 172.859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD..., peaches, pears, pineapples, and plums to retard ripening and spoiling. (d) Sucrose fatty acid esters...

  11. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sucrose fatty acid esters. 172.859 Section 172.859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD..., peaches, pears, pineapples, and plums to retard ripening and spoiling. (d) Sucrose fatty acid esters...

  12. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sucrose fatty acid esters. 172.859 Section 172.859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD..., peaches, pears, pineapples, and plums to retard ripening and spoiling. (d) Sucrose fatty acid esters...

  13. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sucrose fatty acid esters. 172.859 Section 172.859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD..., peaches, pears, pineapples, and plums to retard ripening and spoiling. (d) Sucrose fatty acid esters...

  14. Sucrose and Saccharomyces cerevisiae: a relationship most sweet.

    PubMed

    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.

  15. Switching the mode of sucrose utilization by Saccharomyces cerevisiae

    PubMed Central

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

    2008-01-01

    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 effectively reducing sucrose

  16. Sucrose behenate as a crystallization enhancer for soft fats.

    PubMed

    Domingues, Maria Aliciane Fontenele; da Silva, Thaís Lomonaco Teodoro; Ribeiro, Ana Paula Badan; Chiu, Ming Chih; Gonçalves, Lireny Aparecida Guaraldo

    2016-02-01

    The addition of sucrose behenate for the modification of the physical properties of soft fats, such as soybean oil-based interesterified fat, refined palm oil, and palm mid fraction was studied. The addition of sucrose behenate was verified to affect the crystalline network of fats, changing the hardness and solids profile. The isothermal crystallization behaviors of the fat blends with 1% sucrose behenate were analyzed at 20 and 25 °C. Temperature had a greater effect on the speed of crystallization (k) than the presence of the emulsifier. Sucrose behenate did, however, influence the crystallization mechanism, with changes observed in the Avrami exponent (n). These changes were also observed in the microstructure of the fats. Changes in the polymorphic behavior were observed with the addition of sucrose behenate, such as a possible delay in the α → β transition for interesterified fat, and the initial formation of the β polymorph in palm oil.

  17. Preparative isolation and structural characterization of sucrose ester isomers from oriental tobacco.

    PubMed

    Jia, Chunxiao; Wang, Yingying; Zhu, Yonghua; Xu, Chunping; Mao, Duobin

    2013-05-01

    To date, the structures of the sucrose tetraester (STE) isomers, a main kind of sucrose esters (SEs) in Solanum, have not been conclusively assigned. In this study, three groups of STE isomers with the molecular weight 650, 664 and 678 (designated as STE I, STE II and STE III, respectively) have been isolated and purified from the oriental tobacco-Komotini Basma using a semi-preparative RP-HPLC method. The full characterization of the isomers in the three groups of STE were investigated for the first time by MS (HRMS, MS(2)) and NMR ((1)H, (13)C, HSQC) spectroscopy combined with alkaline hydrolysis and STE derivation experiments. The STE III (a single compound) was confirmed as a known sucrose tetraester. Furthermore, the STE II was found to contain three isomers and the structures were first unambiguously established as 6-O-acetyl (2,3 or 2,4 or 3,4)-di-O-3-methylvaleryl-(4 or 3 or 2)-O-2-methylbutyryl-α-d-glucopyranosyl-β-d-fructofuranoside. Finally, the STE I was discovered to contain seven isomers and the structures were elucidated as 6-O-acetyl (2 or 3 or 4)-O-3-methylvaleryl-(3,4 or 2,4 or 2,3)-di-O-2-methylbutyryl-α-d-glucopyranosyl-β-d-fructofuranoside, 6-O-acetyl (2 or 3 or 4)-O-3-methylvaleryl-(3,4 or 2,4 or 2,3)-di-O-isovaleryl-α-d-glucopyranosyl-β-d-fructofuranoside and 6-O-acetyl (2,3 or 2,4 or 3,4)-di-O-3-methylvaleryl-(4 or 3 or 2)-O-isobutyryl-α-d-glucopyranosyl-β-d-fructofuranoside (one of the 3 isomers). PMID:23542308

  18. A Novel Alkaline α-Galactosidase from Melon Fruit with a Substrate Preference for Raffinose1

    PubMed Central

    Gao, Zhifang; Schaffer, Arthur A.

    1999-01-01

    The cucurbits translocate the galactosyl-sucrose oligosaccharides raffinose and stachyose, therefore, α-galactosidase (α-d-galactoside galactohydrolase, EC 3.2.1.22) is expected to function as the initial enzyme of photoassimilate catabolism. However, the previously described alkaline α-galactosidase is specific for the tetrasaccharide stachyose, leaving raffinose catabolism in these tissues as an enigma. In this paper we report the partial purification and characterization of three α-galactosidases, including a novel alkaline α-galactosidase (form I) from melon (Cucumis melo) fruit tissue. The form I enzyme showed preferred activity with raffinose and significant activity with stachyose. Other unique characteristics of this enzyme, such as weak product inhibition by galactose (in contrast to the other α-galactosidases, which show stronger product inhibition), also impart physiological significance. Using raffinose and stachyose as substrates in the assays, the activities of the three α-galactosidases (alkaline form I, alkaline form II, and the acid form) were measured at different stages of fruit development. The form I enzyme activity increased during the early stages of ovary development and fruit set, in contrast to the other α-galactosidase enzymes, both of which declined in activity during this period. In the mature, sucrose-accumulating mesocarp, the alkaline form I enzyme was the major α-galactosidase present. We also observed hydrolysis of raffinose at alkaline conditions in enzyme extracts from other cucurbit sink tissues, as well as from young Coleus blumei leaves. Our results suggest different physiological roles for the α-galactosidase forms in the developing cucurbit fruit, and show that the newly discovered enzyme plays a physiologically significant role in photoassimilate partitioning in cucurbit sink tissue. PMID:10069835

  19. A novel alkaline alpha-galactosidase from melon fruit with a substrate preference for raffinose

    PubMed

    Gao; Schaffer

    1999-03-01

    The cucurbits translocate the galactosyl-sucrose oligosaccharides raffinose and stachyose, therefore, alpha-galactosidase (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) is expected to function as the initial enzyme of photoassimilate catabolism. However, the previously described alkaline alpha-galactosidase is specific for the tetrasaccharide stachyose, leaving raffinose catabolism in these tissues as an enigma. In this paper we report the partial purification and characterization of three alpha-galactosidases, including a novel alkaline alpha-galactosidase (form I) from melon (Cucumis melo) fruit tissue. The form I enzyme showed preferred activity with raffinose and significant activity with stachyose. Other unique characteristics of this enzyme, such as weak product inhibition by galactose (in contrast to the other alpha-galactosidases, which show stronger product inhibition), also impart physiological significance. Using raffinose and stachyose as substrates in the assays, the activities of the three alpha-galactosidases (alkaline form I, alkaline form II, and the acid form) were measured at different stages of fruit development. The form I enzyme activity increased during the early stages of ovary development and fruit set, in contrast to the other alpha-galactosidase enzymes, both of which declined in activity during this period. In the mature, sucrose-accumulating mesocarp, the alkaline form I enzyme was the major alpha-galactosidase present. We also observed hydrolysis of raffinose at alkaline conditions in enzyme extracts from other cucurbit sink tissues, as well as from young Coleus blumei leaves. Our results suggest different physiological roles for the alpha-galactosidase forms in the developing cucurbit fruit, and show that the newly discovered enzyme plays a physiologically significant role in photoassimilate partitioning in cucurbit sink tissue.

  20. Alkaline battery, separator therefore

    NASA Technical Reports Server (NTRS)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  1. Evaluation of Alkaline Cleaner Materials

    NASA Technical Reports Server (NTRS)

    Partz, Earl

    1998-01-01

    Alkaline cleaners used to process aluminum substrates have contained chromium as the corrosion inhibitor. Chromium is a hazardous substance whose use and control are described by environmental laws. Replacement materials that have the characteristics of chromated alkaline cleaners need to be found that address both the cleaning requirements and environmental impacts. This report will review environmentally friendly candidates evaluated as non-chromium alkaline cleaner replacements and methods used to compare those candidates one versus another. The report will also list characteristics used to select candidates based on their declared contents. It will also describe and evaluate methods used to discriminate among the large number of prospective candidates.

  2. Eco-physiological characteristics of alfalfa seedlings in response to various mixed salt-alkaline stresses.

    PubMed

    Peng, Yong-Lin; Gao, Zhan-Wu; Gao, Ying; Liu, Guo-Fang; Sheng, Lian-Xi; Wang, De-Li

    2008-01-01

    Soil salinization and alkalization frequently co-occur in nature, but little is known about the mixed effects of salt-alkaline stresses on plants. An experiment with mixed salts (NaCl, Na(2)SO(4), NaHCO(3) and Na(2)CO(3)) and 30 salt-alkaline combinations (salinity 24-120 mmol/L and pH 7.03-10.32) treating Medicago sativa seedlings was conducted. The results demonstrated that salinity and alkalinity significantly affected total biomass and biomass components of seedlings. There were interactive effects of salt composition and concentration on biomass (Palkalinity stresses led to changes in the root activity along the salinity gradient (Palkalinity on seedling survival rate were more significant than those of salinity, and the seedlings demonstrated some physiological responses (leaf electrolyte leakage rate and proline content) in order to adapt to mixed salt-alkaline stresses. It was concluded that the mixed salt-alkaline stresses, which differ from either salt or alkali stress, emphasize the significant interaction between salt concentration (salinity) and salt component (alkalinity). Further, the effects of the interaction between high alkalinity and salinity are more severe than those of either salt or alkali stress, and such a cooperative interaction results in more sensitive responses of ecological and physiological characteristics in plants. PMID:18666949

  3. Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter1[OPEN

    PubMed Central

    Yeats, Trevor H.; Sorek, Hagit

    2016-01-01

    In order to understand factors controlling the synthesis and deposition of cellulose, we have studied the Arabidopsis (Arabidopsis thaliana) double mutant shaven3 shaven3-like1 (shv3svl1), which was shown previously to exhibit a marked cellulose deficiency. We discovered that exogenous sucrose (Suc) in growth medium greatly enhances the reduction in hypocotyl elongation and cellulose content of shv3svl1. This effect was specific to Suc and was not observed with other sugars or osmoticum. Live-cell imaging of fluorescently labeled cellulose synthase complexes revealed a slowing of cellulose synthase complexes in shv3svl1 compared with the wild type that is enhanced in a Suc-conditional manner. Solid-state nuclear magnetic resonance confirmed a cellulose deficiency of shv3svl1 but indicated that cellulose crystallinity was unaffected in the mutant. A genetic suppressor screen identified mutants of the plasma membrane Suc/H+ symporter SUC1, indicating that the accumulation of Suc underlies the Suc-dependent enhancement of shv3svl1 phenotypes. While other cellulose-deficient mutants were not specifically sensitive to exogenous Suc, the feronia (fer) receptor kinase mutant partially phenocopied shv3svl1 and exhibited a similar Suc-conditional cellulose defect. We demonstrate that shv3svl1, like fer, exhibits a hyperpolarized plasma membrane H+ gradient that likely underlies the enhanced accumulation of Suc via Suc/H+ symporters. Enhanced intracellular Suc abundance appears to favor the partitioning of carbon to starch rather than cellulose in both mutants. We conclude that SHV3-like proteins may be involved in signaling during cell expansion that coordinates proton pumping and cellulose synthesis. PMID:27013021

  4. Electrophysiological approach to determine kinetic parameters of sucrose uptake by single sieve elements or phloem parenchyma cells in intact Vicia faba plants

    PubMed Central

    Hafke, Jens B.; Höll, Sabina-Roxana; Kühn, Christina; van Bel, Aart J. E.

    2013-01-01

    Apart from cut aphid stylets in combination with electrophysiology, no attempts have been made thus far to measure in vivo sucrose-uptake properties of sieve elements. We investigated the kinetics of sucrose uptake by single sieve elements and phloem parenchyma cells in Vicia faba plants. To this end, microelectrodes were inserted into free-lying phloem cells in the main vein of the youngest fully-expanded leaf, half-way along the stem, in the transition zone between the autotrophic and heterotrophic part of the stem, and in the root axis. A top-to-bottom membrane potential gradient of sieve elements was observed along the stem (−130 mV to −110 mV), while the membrane potential of the phloem parenchyma cells was stable (approx. −100 mV). In roots, the membrane potential of sieve elements dropped abruptly to −55 mV. Bathing solutions having various sucrose concentrations were administered and sucrose/H+-induced depolarizations were recorded. Data analysis by non-linear least-square data fittings as well as by linear Eadie–Hofstee (EH) -transformations pointed at biphasic Michaelis–Menten kinetics (2 MM, EH: Km1 1.2–1.8 mM, Km2 6.6–9.0 mM) of sucrose uptake by sieve elements. However, Akaike's Information Criterion (AIC) favored single MM kinetics. Using single MM as the best-fitting model, Km values for sucrose uptake by sieve elements decreased along the plant axis from 1 to 7 mM. For phloem parenchyma cells, higher Km values (EH: Km1 10 mM, Km2 70 mM) as compared to sieve elements were found. In preliminary patch-clamp experiments with sieve-element protoplasts, small sucrose-coupled proton currents (−0.1 to −0.3 pA/pF) were detected in the whole-cell mode. In conclusion (a) Km values for sucrose uptake measured by electrophysiology are similar to those obtained with heterologous systems, (b) electrophysiology provides a useful tool for in situ determination of Km values, (c) As yet, it remains unclear if one or two uptake systems are involved

  5. Functional Relationship between Sucrose and a Cariogenic Biofilm Formation

    PubMed Central

    Cai, Jian-Na; Jung, Ji-Eun; Dang, Minh-Huy; Kim, Mi-Ah; Yi, Ho-Keun; Jeon, Jae-Gyu

    2016-01-01

    Sucrose is an important dietary factor in cariogenic biofilm formation and subsequent initiation of dental caries. This study investigated the functional relationships between sucrose concentration and Streptococcus mutans adherence and biofilm formation. Changes in morphological characteristics of the biofilms with increasing sucrose concentration were also evaluated. S. mutans biofilms were formed on saliva-coated hydroxyapatite discs in culture medium containing 0, 0.05, 0.1, 0.5, 1, 2, 5, 10, 20, or 40% (w/v) sucrose. The adherence (in 4-hour biofilms) and biofilm composition (in 46-hour biofilms) of the biofilms were analyzed using microbiological, biochemical, laser scanning confocal fluorescence microscopic, and scanning electron microscopic methods. To determine the relationships, 2nd order polynomial curve fitting was performed. In this study, the influence of sucrose on bacterial adhesion, biofilm composition (dry weight, bacterial counts, and water-insoluble extracellular polysaccharide (EPS) content), and acidogenicity followed a 2nd order polynomial curve with concentration dependence, and the maximum effective concentrations (MECs) of sucrose ranged from 0.45 to 2.4%. The bacterial and EPS bio-volume and thickness in the biofilms also gradually increased and then decreased as sucrose concentration increased. Furthermore, the size and shape of the micro-colonies of the biofilms depended on the sucrose concentration. Around the MECs, the micro-colonies were bigger and more homogeneous than those at 0 and 40%, and were surrounded by enough EPSs to support their structure. These results suggest that the relationship between sucrose concentration and cariogenic biofilm formation in the oral cavity could be described by a functional relationship. PMID:27275603

  6. Characteristics of Sucrose Transport through the Sucrose-Specific Porin ScrY Studied by Molecular Dynamics Simulations

    PubMed Central

    Sun, Liping; Bertelshofer, Franziska; Greiner, Günther; Böckmann, Rainer A.

    2016-01-01

    Sucrose-specific porin (ScrY) is a transmembrane protein that allows for the uptake of sucrose under growth-limiting conditions. The crystal structure of ScrY was resolved before by X-ray crystallography, both in its uncomplexed form and with bound sucrose. However, little is known about the molecular characteristics of the transport mechanism of ScrY. To date, there has not yet been any clear demonstration for sucrose transport through the ScrY. Here, the dynamics of the ScrY trimer embedded in a phospholipid bilayer as well as the characteristics of sucrose translocation were investigated by means of atomistic molecular dynamics (MD) simulations. The potential of mean force (PMF) for sucrose translocation through the pore showed two main energy barriers within the constriction region of ScrY. Energy decomposition allowed to pinpoint three aspartic acids as key residues opposing the passage of sucrose, all located within the L3 loop. Mutation of two aspartic acids to uncharged residues resulted in an accordingly modified electrostatics and decreased PMF barrier. The chosen methodology and results will aid in the design of porins with modified transport specificities. PMID:26913282

  7. Effect of vanadate on proton-sucrose cotransport in Ricinus cotyledons

    SciTech Connect

    Vreugdenhil, D.; Spanswick, R.M.

    1987-07-01

    The effects of orthovanadate on the uptake of sucrose by Ricinus cotyledons and on sucrose-coupled proton influx were measured in order to gain insight into the relationship to the plasma membrane proton pump. Vanadate had no effect on short-term sucrose uptake. In long-term experiments (> 30 min) sucrose uptake was progressively inhibited, but only at high external sucrose concentrations. Vanadate did not affect proton efflux pumping in the absence of sucrose and neither did it change the initial rate of sucrose-coupled proton influx. However, it enhanced the maximal level of sucrose-induced alkalization of the medium at all sucrose concentrations tested. This is interpreted as an inhibiting effect of vanadate on the proton pump that recycles protons during sucrose-proton cotransport. The sensitivity towards vanadate indicates that this proton pump is an ATPase. A second proton-translocating system, that is insensitive to vanadate, is postulated to function in the absence of sucrose.

  8. Differential compartmentation of sucrose and gentianose in the cytosol and vacuoles of storage root protoplasts from Gentiana Lutea L.

    PubMed

    Keller, F; Wiemken, A

    1982-12-01

    The storage roots of perennial Gentiana lutea L.plants contain several sugars. The predominant carbohydrate reserve is gentianose (β-D-glucopyranosyl-(1 → 6)-α-D-glucopyranosyl-(1 ↔ 2)-β-D-fructofuranoside). Vacuoles were isolated from root protoplasts and purified through a betaine density gradient. The yield was about 75%. Gentianose and gentiobiose were localized to 100% in the vacuoles, fructose and glucose to about 80%, and sucrose to only about 50%. Taking the volumes of the vacuolar and extravacuolar (cytosolic) compartments into account it is inferred that gentianose is located exclusively in the vacuoles, whilst sucrose is much more concentrated in the cytosol where it may play a role as a cryoprotectant. The concentration of fructose and glucose appeared to be similar on both sides of the tonoplast.

  9. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    NASA Astrophysics Data System (ADS)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  10. Sucrose responsiveness, learning success, and task specialization in ants.

    PubMed

    Perez, Margot; Rolland, Uther; Giurfa, Martin; d'Ettorre, Patrizia

    2013-07-16

    Social insects possess remarkable learning capabilities, which are crucial for their ecological success. They also exhibit interindividual differences in responsiveness to environmental stimuli, which underlie task specialization and division of labor. Here we investigated for the first time the relationships between sucrose responsiveness, behavioral specialization, and appetitive olfactory learning in ants, including reproductive castes. We show that castes of the ant Camponotus aethiops differ in their responsiveness to sucrose and in their learning success in olfactory conditioning experiments in which sucrose is used as reward. Olfactory learning was better in foragers than in nurses, in agreement with their higher sucrose responsiveness. Interindividual variation in stimulus responsiveness and in learning may be, therefore, a crucial factor for division of labor in social insects.

  11. Sucrose substitutes and their role in caries prevention.

    PubMed

    Matsukubo, Takashi; Takazoe, Ichiro

    2006-06-01

    Many non- or low-cariogenic sucrose substitutes are currently available and are found as ingredients of a variety of candy, chewing gum, and drinks. Recently the role of sugar alcohols in promoting remineralisation of enamel has attracted much attention. Thus, the dental profession needs to understand the general characteristics and features of sugar substitutes to provide advice on oral health to patients as well as the general public. There are two critical requirements for sucrose substitutes, namely, being nutritionally appropriate and not being detrimental to the overall general health of the individual. The use of a greater variety of confectionary containing sucrose substitutes and the development of new substitutes with high nutritional value are essential in the battle against caries. In this paper we review in detail the characteristics of sucrose substitutes currently in use, their role in caries prevention and promotion of oral health.

  12. Preference for Sucrose Solutions Modulates Taste Cortical Activity in Humans.

    PubMed

    Jacquin-Piques, Agnès; Mouillot, Thomas; Gigot, Vincent; Meillon, Sophie; Leloup, Corinne; Penicaud, Luc; Brondel, Laurent

    2016-09-01

    High time resolution is required to reliably measure neuronal activity in the gustatory cortex in response to taste stimuli. Hedonic aspects of gustatory processing have never been explored using gustatory evoked potentials (GEPs), a high-time-resolution technique. Our aim was to study cerebral processing of hedonic taste in humans using GEPs in response to sucrose solutions in subjects with different ratings of pleasantness regarding sucrose. In this exploratory study, 30 healthy volunteers were randomly stimulated with 3 sucrose solutions. The sucrose stimulus was presented to the tongue for 1s 20 times. GEPs were recorded from 9 cortical sites with EEG sensors at Cz, Fz, Pz, C3, C4, F3, F4, Fp1, and Fp2 (10/20 system). The main result was that subjects who preferred the high-concentration (20g/100mL) sucrose solution had higher GEP amplitudes on the Pz, Cz, and Fz electrodes than did subjects who preferred the low-concentration (5g/100mL) or the moderate-concentration (10g/100mL) solutions regardless of stimulus intensity. The difference in P1N1 amplitude on the Pz, Cz, and Fz electrodes according to sucrose preference of the subjects was described with stronger significance with stimulation by the 20 g-sucrose solution than by the 5 and 10g sucrose solutions. Using the reliable and safe GEP technique, we provide an original demonstration of variability of the gustatory response on the Pz, Cz, and Fz electrodes according to a sweet preference in humans. Further studies are needed to correlate the electric signal recorded by surface electrodes to the neural generator. PMID:27235187

  13. Sucrose Improves Insecticide Activity Against Drosophila suzukii (Diptera: Drosophilidae).

    PubMed

    Cowles, Richard S; Rodriguez-Saona, Cesar; Holdcraft, Robert; Loeb, Gregory M; Elsensohn, Johanna E; Hesler, Steven P

    2015-04-01

    The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests. In the laboratory, 0.1% sucrose added to a spray solution enhanced spotted wing drosophila feeding. Flies died 120 min earlier when exposed to spinosad residues at label rates enhanced with sucrose. Added sucrose reduced the LC50 for dried acetamiprid residues from 82 to 41 ppm in the spray solution. Laboratory bioassays of spotted wing drosophila mortality followed exposure to grape and blueberry foliage and/or fruit sprayed and aged in the field. On grape foliage, the addition of 2.4 g/liter of sugar with insecticide sprays resulted in an 11 and 6% increase of spotted wing drosophila mortality at 1 and 2 d exposures to residues, respectively, averaged over seven insecticides with three concentrations. In a separate experiment, spinetoram and cyantraniliprole reduced by 95-100% the larval infestation of blueberries, relative to the untreated control, 7 d after application at labeled rates when applied with 1.2 g/liter sucrose in a spray mixture, irrespective of rainfall; without sucrose infestation was reduced by 46-91%. Adding sugar to the organically acceptable spinosyn, Entrust, reduced larval infestation of strawberries by >50% relative to without sugar for five of the six sample dates during a season-long field trial. In a small-plot field test with blueberries, weekly applications in alternating sprays of sucrose plus reduced-risk insecticides, spinetoram or acetamiprid, reduced larval infestation relative to the untreated control by 76%; alternating bifenthrin and phosmet (without sucrose) reduced infestation by 65%.

  14. Sucrose Improves Insecticide Activity Against Drosophila suzukii (Diptera: Drosophilidae).

    PubMed

    Cowles, Richard S; Rodriguez-Saona, Cesar; Holdcraft, Robert; Loeb, Gregory M; Elsensohn, Johanna E; Hesler, Steven P

    2015-04-01

    The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests. In the laboratory, 0.1% sucrose added to a spray solution enhanced spotted wing drosophila feeding. Flies died 120 min earlier when exposed to spinosad residues at label rates enhanced with sucrose. Added sucrose reduced the LC50 for dried acetamiprid residues from 82 to 41 ppm in the spray solution. Laboratory bioassays of spotted wing drosophila mortality followed exposure to grape and blueberry foliage and/or fruit sprayed and aged in the field. On grape foliage, the addition of 2.4 g/liter of sugar with insecticide sprays resulted in an 11 and 6% increase of spotted wing drosophila mortality at 1 and 2 d exposures to residues, respectively, averaged over seven insecticides with three concentrations. In a separate experiment, spinetoram and cyantraniliprole reduced by 95-100% the larval infestation of blueberries, relative to the untreated control, 7 d after application at labeled rates when applied with 1.2 g/liter sucrose in a spray mixture, irrespective of rainfall; without sucrose infestation was reduced by 46-91%. Adding sugar to the organically acceptable spinosyn, Entrust, reduced larval infestation of strawberries by >50% relative to without sugar for five of the six sample dates during a season-long field trial. In a small-plot field test with blueberries, weekly applications in alternating sprays of sucrose plus reduced-risk insecticides, spinetoram or acetamiprid, reduced larval infestation relative to the untreated control by 76%; alternating bifenthrin and phosmet (without sucrose) reduced infestation by 65%. PMID:26470175

  15. Effect of sucrose-containing snacks on blood glucose control.

    PubMed

    Wise, J E; Keim, K S; Huisinga, J L; Willmann, P A

    1989-06-01

    To determine whether ingestion of sucrose-containing snacks would affect blood glucose (BG) control, 16 subjects with insulin-dependent diabetes mellitus participated in a 5-day double-blind study at a diabetes camp. Eight subjects in the sucrose group ate sucrose-sweetened snacks twice a day, and 8 subjects in the control group ingested snacks that were sweetened with aspartame. The percentage of total daily calories derived from added sucrose was 7% for the sucrose group and 1% for the control group. Metabolic control was assessed by daily capillary BG measurements obtained before meals and the bedtime snack and by determination of serum fructosamine (F) concentrations on arrival at camp (day 0) and after 5 days on the study protocol (day 5). No significant difference was seen between the groups on day 0 (sucrose group [mean +/- SD]: BG 9.9 +/- 3.6 mM, F 3.54 +/- 0.38 mM; control group: BG 9.1 +/- 2.8 mM, F 3.74 +/- 0.71 mM) or day 5 (sucrose group: BG 8.8 +/- 2.6 mM, F 2.94 +/- 0.32 mM; control group: BG 7.4 +/- 2.8 mM, F 2.92 +/- 0.59 mM). We conclude that ingestion of sucrose, added to snacks in an amount up to 7% of total energy intake, does not adversely affect short-term BG control.

  16. Effects of Soil Salinity on Sucrose Metabolism in Cotton Leaves

    PubMed Central

    Zhang, Lei; Luo, Junyu; Dong, Helin; Ma, Yan; Zhao, Xinhua; Chen, Binglin; Sui, Ning; Zhou, Zhiguo; Meng, Yali

    2016-01-01

    This study investigated sucrose metabolism of the youngest fully expanded main-stem leaf (MSL) and the subtending leaf of cotton (Gossypium hirsutum L.) boll (LSCB) of salt-tolerant (CCRI-79) and salt-sensitive (Simian 3) cultivars and its relationship to boll weight under low, medium and high soil salinity stress in Dafeng, China, in 2013 and 2014. The results showed that with increased soil salinity, 1) both the chlorophyll content and net photosynthetic rate (Pn) decreased, while the internal CO2 concentration firstly declined, and then increased in the MSL and LSCB; 2) carbohydrate contents in the MSL reduced significantly, while sucrose and starch contents in the LSCB increased, as did the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SuSy) in both the MSL and LSCB; 3) but invertase activity in both the MSL and LSCB did not change significantly. Our study also showed that the LSCB was more sensitive to soil salinity than was the MSL. Of the measured physiological indices, higher SPS activity, mainly controlled by sps3, may contribute to adaption of the LSCB to soil salinity stress because SPS is beneficial for efficiently sucrose synthesis, reduction of cellular osmotic potential and combined actions of Pn, and sucrose transformation rate and SPS may contribute to the reduction in boll weight under soil salinity stress. PMID:27228029

  17. Effects of Soil Salinity on Sucrose Metabolism in Cotton Leaves.

    PubMed

    Peng, Jun; Liu, Jingran; Zhang, Lei; Luo, Junyu; Dong, Helin; Ma, Yan; Zhao, Xinhua; Chen, Binglin; Sui, Ning; Zhou, Zhiguo; Meng, Yali

    2016-01-01

    This study investigated sucrose metabolism of the youngest fully expanded main-stem leaf (MSL) and the subtending leaf of cotton (Gossypium hirsutum L.) boll (LSCB) of salt-tolerant (CCRI-79) and salt-sensitive (Simian 3) cultivars and its relationship to boll weight under low, medium and high soil salinity stress in Dafeng, China, in 2013 and 2014. The results showed that with increased soil salinity, 1) both the chlorophyll content and net photosynthetic rate (Pn) decreased, while the internal CO2 concentration firstly declined, and then increased in the MSL and LSCB; 2) carbohydrate contents in the MSL reduced significantly, while sucrose and starch contents in the LSCB increased, as did the activities of sucrose phosphate synthase (SPS) and sucrose synthase (SuSy) in both the MSL and LSCB; 3) but invertase activity in both the MSL and LSCB did not change significantly. Our study also showed that the LSCB was more sensitive to soil salinity than was the MSL. Of the measured physiological indices, higher SPS activity, mainly controlled by sps3, may contribute to adaption of the LSCB to soil salinity stress because SPS is beneficial for efficiently sucrose synthesis, reduction of cellular osmotic potential and combined actions of Pn, and sucrose transformation rate and SPS may contribute to the reduction in boll weight under soil salinity stress. PMID:27228029

  18. Responding for sucrose and wheel-running reinforcement: effects of sucrose concentration and wheel-running reinforcer duration.

    PubMed Central

    Belke, Terry W; Hancock, Stephanie D

    2003-01-01

    Six male albino rats were placed in running wheels and exposed to a fixed-interval 30-s schedule of lever pressing that produced either a drop of sucrose solution or the opportunity to run for a fixed duration as reinforcers. Each reinforcer type was signaled by a different stimulus. In Experiment 1, the duration of running was held constant at 15 s while the concentration of sucrose solution was varied across values of 0, 2.5. 5, 10, and 15%. As concentration decreased, postreinforcement pause duration increased and local rates decreased in the presence of the stimulus signaling sucrose. Consequently, the difference between responding in the presence of stimuli signaling wheel-running and sucrose reinforcers diminished, and at 2.5%, response functions for the two reinforcers were similar. In Experiment 2, the concentration of sucrose solution was held constant at 15% while the duration of the opportunity to run was first varied across values of 15, 45, and 90 s then subsequently across values of 5, 10, and 15 s. As run duration increased, postreinforcement pause duration in the presence of the wheel-running stimulus increased and local rates increased then decreased. In summary, inhibitory aftereffects of previous reinforcers occurred when both sucrose concentration and run duration varied; changes in responding were attributable to changes in the excitatory value of the stimuli signaling the two reinforcers. PMID:12822690

  19. Drought response transcriptomes are altered in poplar with reduced tonoplast sucrose transporter expression

    PubMed Central

    Xue, Liang-Jiao; Frost, Christopher J.; Tsai, Chung-Jui; Harding, Scott A.

    2016-01-01

    Transgenic Populus tremula x alba (717-1B4) plants with reduced expression of a tonoplast sucrose efflux transporter, PtaSUT4, exhibit reduced shoot growth compared to wild type (WT) under sustained mild drought. The present study was undertaken to determine whether SUT4-RNAi directly or indirectly altered poplar predisposition and/or response to changes in soil water availability. While sucrose and hexose levels were constitutively elevated in shoot organs, expression responses to drought were most altered in the root tips of SUT4-RNAi plants. Prior to any drought treatment, constitutively elevated transcript levels of abscisic acid biosynthetic genes and bark/vegetative storage proteins suggested altered metabolism in root tips of RNAi plants. Stronger drought-stimulation of stress-inducible genes encoding late-embryogenesis-abundant proteins in transgenic roots was consistent with increased vulnerability to soil drying. Transcript evidence suggested an RNAi effect on intercellular water trafficking by aquaporins in stem xylem during soil drying and recovery. Co-expression network analysis predicted altered integration of abscisic acid sensing/signaling with ethylene and jasmonate sensing/signaling in RNAi compared to WT roots. The overall conclusion is that steepened shoot-root sugar gradient in RNAi plants increased sensitivity of root tips to decreasing soil water availability. PMID:27641356

  20. Drought response transcriptomes are altered in poplar with reduced tonoplast sucrose transporter expression.

    PubMed

    Xue, Liang-Jiao; Frost, Christopher J; Tsai, Chung-Jui; Harding, Scott A

    2016-01-01

    Transgenic Populus tremula x alba (717-1B4) plants with reduced expression of a tonoplast sucrose efflux transporter, PtaSUT4, exhibit reduced shoot growth compared to wild type (WT) under sustained mild drought. The present study was undertaken to determine whether SUT4-RNAi directly or indirectly altered poplar predisposition and/or response to changes in soil water availability. While sucrose and hexose levels were constitutively elevated in shoot organs, expression responses to drought were most altered in the root tips of SUT4-RNAi plants. Prior to any drought treatment, constitutively elevated transcript levels of abscisic acid biosynthetic genes and bark/vegetative storage proteins suggested altered metabolism in root tips of RNAi plants. Stronger drought-stimulation of stress-inducible genes encoding late-embryogenesis-abundant proteins in transgenic roots was consistent with increased vulnerability to soil drying. Transcript evidence suggested an RNAi effect on intercellular water trafficking by aquaporins in stem xylem during soil drying and recovery. Co-expression network analysis predicted altered integration of abscisic acid sensing/signaling with ethylene and jasmonate sensing/signaling in RNAi compared to WT roots. The overall conclusion is that steepened shoot-root sugar gradient in RNAi plants increased sensitivity of root tips to decreasing soil water availability. PMID:27641356

  1. Effect of Dietary Intake of Avocado Oil and Olive Oil on Biochemical Markers of Liver Function in Sucrose-Fed Rats

    PubMed Central

    Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, Ma. Guadalupe; Melo Santiesteban, Guadalupe; Hayward-Jones, Patricia M.; Barradas-Dermitz, Dulce Ma.

    2014-01-01

    Metabolic changes, along with cardiovascular and hepatic factors, are associated with the development of diseases such as diabetes, dyslipidemia, and obesity. We evaluated the effect of avocado oil supplementation (centrifuged and solvent extracted), compared with olive oil, upon the hepatic function in sucrose-fed rats. Twenty-five rats were divided into five groups: control (basal diet), a sucrose-fed group (basal diet plus 30% sucrose solution), and three other groups (S-OO, S-AOC, and S-AOS, indicating basal diet plus 30% sucrose solution plus olive oil OO, avocado oil extracted by centrifugation AOC or using solvent AOS, resp.). Glucose, total cholesterol, triglycerides, total protein, albumin, globulin, direct bilirubin, glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, alkaline phosphatase, cholinesterase, and α-amylase concentrations were determined and avocado oil effect on them was studied. In some cases the induced metabolic alteration significantly affected total protein and bilirubin levels and also had a highly significant effect on α-amylase levels. AOC and AOS exhibited effects similar to those of olive oil, according to the nonsignificant difference in fatty acid profile observed by other authors. Avocado oil consumption could be beneficial in the control of altered metabolic profile illnesses as it presents effects on hepatic function biochemical markers similar to olive oil. PMID:24860825

  2. Comparative study of root growth and sucrose-cleaving enzymes in metallicolous and non-metallicolous populations of Rumex dentatus under copper stress.

    PubMed

    Cai, Shen-Wen; Huang, Wu-Xing; Xiong, Zhi-Ting; Ye, Feng-Ya; Ren, Cong; Xu, Zhong-Rui; Liu, Chen; Deng, Song-Qiang; Zhao, Jing

    2013-12-01

    Sucrose metabolism in roots of metallophytes is very important for root growth and maintenance of heavy metal tolerance. However, rare researches have been carried out on this topic so far. We tested here a hypothesis that roots of copper-tolerant plants should manifest higher activities of sucrose-cleaving enzymes than non-tolerant plants for maintaining root growth under Cu stress. Plants of two contrasting populations of metallophyte Rumex dentatus, one from an ancient Cu mine (MP) and the other from a non-mine site (NMP), were treated with Cu in controlled experiments. Cu treatment resulted in a higher root biomass and root/shoot biomass ratio in MP compared to NMP. More complicated root system architecture was showed in MP under Cu stress. Activities and transcript levels of acid invertase as well as contents of sucrose and reducing sugar in MP were elevated under Cu treatment, while activities of neutral/alkaline invertase and sucrose synthase showed no significant differences between two populations. The results indicate important roles of acid invertase in governing root growth under Cu stress.

  3. Effect of dietary intake of avocado oil and olive oil on biochemical markers of liver function in sucrose-fed rats.

    PubMed

    Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, Ma Guadalupe; Melo Santiesteban, Guadalupe; Hayward-Jones, Patricia M; Barradas-Dermitz, Dulce Ma

    2014-01-01

    Metabolic changes, along with cardiovascular and hepatic factors, are associated with the development of diseases such as diabetes, dyslipidemia, and obesity. We evaluated the effect of avocado oil supplementation (centrifuged and solvent extracted), compared with olive oil, upon the hepatic function in sucrose-fed rats. Twenty-five rats were divided into five groups: control (basal diet), a sucrose-fed group (basal diet plus 30% sucrose solution), and three other groups (S-OO, S-AOC, and S-AOS, indicating basal diet plus 30% sucrose solution plus olive oil OO, avocado oil extracted by centrifugation AOC or using solvent AOS, resp.). Glucose, total cholesterol, triglycerides, total protein, albumin, globulin, direct bilirubin, glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, alkaline phosphatase, cholinesterase, and α -amylase concentrations were determined and avocado oil effect on them was studied. In some cases the induced metabolic alteration significantly affected total protein and bilirubin levels and also had a highly significant effect on α -amylase levels. AOC and AOS exhibited effects similar to those of olive oil, according to the nonsignificant difference in fatty acid profile observed by other authors. Avocado oil consumption could be beneficial in the control of altered metabolic profile illnesses as it presents effects on hepatic function biochemical markers similar to olive oil.

  4. The Origin of Life in Alkaline Hydrothermal Vents.

    PubMed

    Sojo, Victor; Herschy, Barry; Whicher, Alexandra; Camprubí, Eloi; Lane, Nick

    2016-02-01

    Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea.

  5. Catalytic Diversity in Alkaline Hydrothermal Vent Systems on Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Cameron, Ryan D.; Barge, Laura; Chin, Keith B.; Doloboff, Ivria J.; Flores, Erika; Hammer, Arden C.; Sobron, Pablo; Russell, Michael J.; Kanik, Isik

    2016-10-01

    Hydrothermal systems formed by serpentinization can create moderate-temperature, alkaline systems and it is possible that this type of vent could exist on icy worlds such as Europa which have water-rock interfaces. It has been proposed that some prebiotic chemistry responsible for the emergence of life on Earth and possibly other wet and icy worlds could occur as a result ofredox potential and pH gradients in submarine alkaline hydrothermal vents (Russell et al., 2014). Hydrothermal chimneys formed in laboratory simulations of alkaline vents under early Earth conditions have precipitate membranes that contain minerals such as iron sulfides, which are hypothesized to catalyze reduction of CO2 (Yamaguchi et al. 2014, Roldan et al. 2014) leading to further organic synthesis. This CO2 reduction process may be affected by other trace components in the chimney, e.g. nickel or organic molecules. We have conducted experiments to investigate catalytic properties of iron and iron-nickel sulfides containing organic dopants in slightly acidic ocean simulants relevant to early Earth or possibly ocean worlds. We find that the electrochemical properties of the chimney as well as the morphology/chemistry of the precipitate are affected by the concentration and type of organics present. These results imply that synthesis of organics in water-rock systems on ocean worlds may lead to hydrothermal precipitates which can incorporate these organic into the mineral matrix and may affect the role of gradients in alkaline vent systems.Therefore, further understanding on the electroactive roles of various organic species within hydrothermal chimneys will have important implications for habitability as well as prebiotic chemistry. This work is funded by NASA Astrobiology Institute JPL Icy Worlds Team and a NAI Director's Discretionary Fund award.Yamaguchi A. et al. (2014) Electrochimica Acta, 141, 311–318.Russell, M. J. et al. (2014), Astrobiology, 14, 308-43.Roldan, A. (2014) Chem. Comm

  6. The Origin of Life in Alkaline Hydrothermal Vents.

    PubMed

    Sojo, Victor; Herschy, Barry; Whicher, Alexandra; Camprubí, Eloi; Lane, Nick

    2016-02-01

    Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea. PMID:26841066

  7. Expression analysis of genes associated with sucrose accumulation in sugarcane (Saccharum spp. hybrids) varieties differing in content and time of peak sucrose storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sucrose synthesis/accumulation in sugarcane is a complex process involving many genes and regulatory sequences that control biochemical events in source-sink tissues. Among these, sucrose synthase (SuSy), sucrose-phosphate synthase (SPS), soluble acid (SAI) and cell-wall invertase (CWI) are importan...

  8. The theoretical shape of sucrose crystals from energy calculations

    NASA Astrophysics Data System (ADS)

    Saska, Michael; Myerson, Allan S.

    1983-05-01

    The surface energies of individual crystallographic faces of crystalline sucrose were calculated using two forms of the 6-exp (Buckingham) potential. Hydrogen bond energies were calculated as a sum of O-H, O…H and O…O interactions where the Lippincott-Schroeder short-range potential was used for O-H and O…H pairs and the 6-exp potential for the non-bonded O…O interactions. Assuming that the surface energy equals half of the cohesive energy of the crystal, the attachment and surface energies of most of the faces found on as sucrose crystal were calculated. A computer program was written to draw the theoretical shape of crystals given the positions (central distances) of its faces. The resulting sucrose shapes are elongated along the c-axis. It is argued that the c-axis elongated habit is an intrinsic shape for vapor grown sucrose crystals (if realizable) and it is suggested that the usual shapes of solution grown sucrose crystals can be explained in terms of solvent (water) adsorption.

  9. Pharmaceutical micro-particles give amorphous sucrose higher physical stability.

    PubMed

    Hellrup, Joel; Mahlin, Denny

    2011-05-16

    The aim of this study was to explore how pharmaceutical micro-sized filler particles affect the amorphous stability of sucrose in sucrose/filler particle composites produced by freeze-drying. Focus was put on the filler particles' properties crystallinity, hygroscopicity, hydrophobicity, and surface area, and their influence on physical stability of the amorphous phase. The micro-sized filler particles were examined with Blaine permeametry, gas adsorption, pycnometry, gravimetric vapour sorption, X-ray diffraction, and light microscopy before composites of sucrose and micro-sized filler particles were prepared by freeze-drying. The stability of the composites was examined with X-ray diffraction, differential scanning calorimetry (DSC), and microcalorimetry. All composites were amorphous and showed higher stability compared to pure amorphous sucrose, which was evident from a delay in heat and moisture-induced crystallization. However, calcium carbonate and oxazepam micro-sized filler particles lost their ability to stabilize the amorphous sucrose when exposed to humidity. The dry glass transition temperature (T(g)) was higher for the composites, indicating the stabilization was mediated by a reduced molecular mobility of the amorphous phase. PMID:21356288

  10. Sucrose metabolism gene families and their biological functions.

    PubMed

    Jiang, Shu-Ye; Chi, Yun-Hua; Wang, Ji-Zhou; Zhou, Jun-Xia; Cheng, Yan-Song; Zhang, Bao-Lan; Ma, Ali; Vanitha, Jeevanandam; Ramachandran, Srinivasan

    2015-11-30

    Sucrose, as the main product of photosynthesis, plays crucial roles in plant development. Although studies on general metabolism pathway were well documented, less information is available on the genome-wide identification of these genes, their expansion and evolutionary history as well as their biological functions. We focused on four sucrose metabolism related gene families including sucrose synthase, sucrose phosphate synthase, sucrose phosphate phosphatase and UDP-glucose pyrophosphorylase. These gene families exhibited different expansion and evolutionary history as their host genomes experienced differentiated rates of the whole genome duplication, tandem and segmental duplication, or mobile element mediated gene gain and loss. They were evolutionarily conserved under purifying selection among species and expression divergence played important roles for gene survival after expansion. However, we have detected recent positive selection during intra-species divergence. Overexpression of 15 sorghum genes in Arabidopsis revealed their roles in biomass accumulation, flowering time control, seed germination and response to high salinity and sugar stresses. Our studies uncovered the molecular mechanisms of gene expansion and evolution and also provided new insight into the role of positive selection in intra-species divergence. Overexpression data revealed novel biological functions of these genes in flowering time control and seed germination under normal and stress conditions.

  11. Adverse effects of sucrose-rich diets on uraemic rats.

    PubMed

    Laouari, D; Kleinknecht, C; Burtin, M; Hinglais, N; Lacour, B; Landais, P; Broyer, M

    1990-01-01

    The nature of carbohydrate may affect the tolerance and progression of uraemia. The effects of three diets differing only in their carbohydrate source: namely corn starch (C), glucose (G) or sucrose (S) were examined. Study 1 examined the effects of the three carbohydrate diets on unilaterally nephrectomised control rats and severely uraemic rats. The three carbohydrates produced similar nutritional effects in uninephrectomised rats, whereas sucrose rapidly induced anorexia, stunting and slightly accelerated renal damage in uraemia. Study 2 examined the long-term effects of the three carbohydrates in moderate uraemia under conditions of high and identical carbohydrate intakes. Hyperphagic Zucker uraemic rats (F rats) received a daily allotment of each diet plus pure carbohydrate. Lean uraemic rats (L rats) received the same dietary allotment without the carbohydrate supplement. The F rats fed sucrose showed greater morbidity and mortality but little renal deterioration. Their plasma triglycerides increased dramatically. The L rats fed sucrose had the greatest urinary protein, the least creatinine clearance and the most severe renal damage. Thus, sucrose-rich but not glucose-rich diets have two adverse effects in uraemia: a deterioration in nutritional status, perhaps related to abnormal fructose utilisation, and a long-term effect on the kidney, resulting in accelerated renal deterioration.

  12. SUCROSE SYNTHASE: ELUCIDATION OF COMPLEX POST-TRANSLATIONAL REGULATORY MECHANISMS

    SciTech Connect

    Steven C. Huber

    2009-05-12

    Studies have focused on the enzyme sucrose synthase, which plays an important role in the metabolism of sucrose in seeds and tubers. There are three isoforms of SUS in maize, referred to as SUS1, SUS-SH1, and SUS2. SUS is generally considered to be tetrameric protein but recent evidence suggests that SUS can also occur as a dimeric protein. The formation of tetrameric SUS is regulated by sucrose concentration in vitro and this could also be an important factor in the cellular localization of the protein. We found that high sucrose concentrations, which promote tetramer formation, also inhibit the binding of SUS1 to actin filaments in vitro. Previously, high sucrose concentrations were shown to promote SUS association with the plasma membrane. The specific regions of the SUS molecule involved in oligomerization are not known, but we identified a region of the SUS1 moelcule by bioinformatic analysis that was predicted to form a coiled coil. We demonstrated that this sequence could, in fact, self-associate as predicted for a coiled coil, but truncation analysis with the full-length recombinant protein suggested that it was not responsible for formation of dimers or tetramers. However, the coiled coil may function in binding of other proteins to SUS1. Overall, sugar availability may differentially influence the binding of SUS to cellular structures, and these effects may be mediated by changes in the oligomeric nature of the enzyme.

  13. Sucrose metabolism gene families and their biological functions

    PubMed Central

    Jiang, Shu-Ye; Chi, Yun-Hua; Wang, Ji-Zhou; Zhou, Jun-Xia; Cheng, Yan-Song; Zhang, Bao-Lan; Ma, Ali; Vanitha, Jeevanandam; Ramachandran, Srinivasan

    2015-01-01

    Sucrose, as the main product of photosynthesis, plays crucial roles in plant development. Although studies on general metabolism pathway were well documented, less information is available on the genome-wide identification of these genes, their expansion and evolutionary history as well as their biological functions. We focused on four sucrose metabolism related gene families including sucrose synthase, sucrose phosphate synthase, sucrose phosphate phosphatase and UDP-glucose pyrophosphorylase. These gene families exhibited different expansion and evolutionary history as their host genomes experienced differentiated rates of the whole genome duplication, tandem and segmental duplication, or mobile element mediated gene gain and loss. They were evolutionarily conserved under purifying selection among species and expression divergence played important roles for gene survival after expansion. However, we have detected recent positive selection during intra-species divergence. Overexpression of 15 sorghum genes in Arabidopsis revealed their roles in biomass accumulation, flowering time control, seed germination and response to high salinity and sugar stresses. Our studies uncovered the molecular mechanisms of gene expansion and evolution and also provided new insight into the role of positive selection in intra-species divergence. Overexpression data revealed novel biological functions of these genes in flowering time control and seed germination under normal and stress conditions. PMID:26616172

  14. Effect of sucrose on the metabolic disposition of aspartame.

    PubMed

    Stegink, L D; Brummel, M C; Persoon, T J; Filer, L J; Bell, E F; Ziegler, E E

    1990-08-01

    Twelve normal adult subjects ingested a beverage providing 0.136 mmol aspartame/kg body wt on 2 different days. On 1 study day the beverage provided only aspartame, on the other the beverage provided both aspartame and 3.51 mmol sucrose/kg body wt. The high mean plasma phenylalanine concentrations were similar after administration of aspartame alone (158 +/- 28.9 mumol/L, mean +/- SD) and administration of aspartame plus sucrose (134 +/- 44.1 mumol/L). Evaluation of the area under the plasma concentration-time curve (AUC) for phenylalanine also showed no significant difference between groups (197 +/- 49.1 vs 182 +/- 28.3 mumol.L-1.h for aspartame alone and aspartame plus sucrose, respectively). Similarly, the high mean ratio of phenylalanine to large neutral amino acids (Phe:LNAA) in plasma did not differ significantly (0.265 +/- 0.046 for aspartame alone, 0.275 +/- 0.107 for aspartame plus sucrose). However, there was a small but significant difference between groups for the 4-h AUC values for plasma Phe:LNAA. The simultaneous ingestion of sucrose with aspartame had only minor effects on aspartame's metabolic disposition.

  15. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    NASA Astrophysics Data System (ADS)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  16. Glucose and sucrose: hazardous fast-food for industrial yeast?

    PubMed

    Verstrepen, Kevin J; Iserentant, Dirk; Malcorps, Philippe; Derdelinckx, Guy; Van Dijck, Patrick; Winderickx, Joris; Pretorius, Isak S; Thevelein, Johan M; Delvaux, Freddy R

    2004-10-01

    Yeast cells often encounter a mixture of different carbohydrates in industrial processes. However, glucose and sucrose are always consumed first. The presence of these sugars causes repression of gluconeogenesis, the glyoxylate cycle, respiration and the uptake of less-preferred carbohydrates. Glucose and sucrose also trigger unexpected, hormone-like effects, including the activation of cellular growth, the mobilization of storage compounds and the diminution of cellular stress resistance. In an industrial context, these effects lead to several yeast-related problems, such as slow or incomplete fermentation, 'off flavors' and poor maintenance of yeast vitality. Recent studies indicate that the use of mutants with altered responses to carbohydrates can significantly increase productivity. Alternatively, avoiding unnecessary exposure to glucose and sucrose could also improve the performance of industrial yeasts.

  17. Taste preference thresholds for Polycose, maltose, and sucrose in rats.

    PubMed

    Sclafani, A; Nissenbaum, J W

    1987-01-01

    The taste preference thresholds of adult female rats for polysaccharide (Polycose), maltose, and sucrose were compared. The nondeprived animals were given 24-hr two-bottle preference tests (saccharide solution vs. water) and, starting at 0.008%, the saccharide concentration was increased daily. The rats first preferred the Polycose solution to water at 0.01% (0.0001 M), the maltose solution to water at 0.09% (0.0025 M), and the sucrose solution to water at 0.09% (0.0026 M). Thus, on a molar basis the rats' Polycose threshold was 25 to 26 times lower than their maltose and sucrose threshold. It was postulated that the low taste threshold for polysaccharides allows the rat to detect starch which, unlike sugar, is very low in solubility.

  18. The Structure of Sucrose Synthase-1 from Arabidopsis thaliana and Its Functional Implications

    SciTech Connect

    Zheng, Yi; Anderson, Spencer; Zhang, Yanfeng; Garavito, R. Michael

    2014-10-02

    Sucrose transport is the central system for the allocation of carbon resources in vascular plants. During growth and development, plants control carbon distribution by coordinating sites of sucrose synthesis and cleavage in different plant organs and different cellular locations. Sucrose synthase, which reversibly catalyzes sucrose synthesis and cleavage, provides a direct and reversible means to regulate sucrose flux. Depending on the metabolic environment, sucrose synthase alters its cellular location to participate in cellulose, callose, and starch biosynthesis through its interactions with membranes, organelles, and cytoskeletal actin. The x-ray crystal structure of sucrose synthase isoform 1 from Arabidopsis thaliana (AtSus1) has been determined as a complex with UDP-glucose and as a complex with UDP and fructose, at 2.8- and 2.85-{angstrom} resolutions, respectively. The AtSus1 structure provides insights into sucrose catalysis and cleavage, as well as the regulation of sucrose synthase and its interactions with cellular targets.

  19. The Structure of Sucrose Synthase-1 from Arabidopsis thaliana and Its Functional Implications*

    PubMed Central

    Zheng, Yi; Anderson, Spencer; Zhang, Yanfeng; Garavito, R. Michael

    2011-01-01

    Sucrose transport is the central system for the allocation of carbon resources in vascular plants. During growth and development, plants control carbon distribution by coordinating sites of sucrose synthesis and cleavage in different plant organs and different cellular locations. Sucrose synthase, which reversibly catalyzes sucrose synthesis and cleavage, provides a direct and reversible means to regulate sucrose flux. Depending on the metabolic environment, sucrose synthase alters its cellular location to participate in cellulose, callose, and starch biosynthesis through its interactions with membranes, organelles, and cytoskeletal actin. The x-ray crystal structure of sucrose synthase isoform 1 from Arabidopsis thaliana (AtSus1) has been determined as a complex with UDP-glucose and as a complex with UDP and fructose, at 2.8- and 2.85-Å resolutions, respectively. The AtSus1 structure provides insights into sucrose catalysis and cleavage, as well as the regulation of sucrose synthase and its interactions with cellular targets. PMID:21865170

  20. Deregulation of Sucrose-Controlled Translation of a bZIP-Type Transcription Factor Results in Sucrose Accumulation in Leaves

    PubMed Central

    Lee, Sung Shin; Yang, Seung Hwan; Zhu, XuJun; Imai, Ryozo; Takahashi, Yoshihiro; Kusano, Tomonobu

    2012-01-01

    Sucrose is known to repress the translation of Arabidopsis thaliana AtbZIP11 transcript which encodes a protein belonging to the group of S (S - stands for small) basic region-leucine zipper (bZIP)-type transcription factor. This repression is called sucrose-induced repression of translation (SIRT). It is mediated through the sucrose-controlled upstream open reading frame (SC-uORF) found in the AtbZIP11 transcript. The SIRT is reported for 4 other genes belonging to the group of S bZIP in Arabidopsis. Tobacco tbz17 is phylogenetically closely related to AtbZIP11 and carries a putative SC-uORF in its 5′-leader region. Here we demonstrate that tbz17 exhibits SIRT mediated by its SC-uORF in a manner similar to genes belonging to the S bZIP group of the Arabidopsis genus. Furthermore, constitutive transgenic expression of tbz17 lacking its 5′-leader region containing the SC-uORF leads to production of tobacco plants with thicker leaves composed of enlarged cells with 3–4 times higher sucrose content compared to wild type plants. Our finding provides a novel strategy to generate plants with high sucrose content. PMID:22457737

  1. Long-term alkalinity decrease and acidification of estuaries in northwestern Gulf of Mexico.

    PubMed

    Hu, Xinping; Pollack, Jennifer Beseres; McCutcheon, Melissa R; Montagna, Paul A; Ouyang, Zhangxian

    2015-03-17

    More than four decades of alkalinity and pH data (late 1960s to 2010) from coastal bays along the northwestern Gulf of Mexico were analyzed for temporal changes across a climatic gradient of decreasing rainfall and freshwater inflow, from northeast to southwest. The majority (16 out of 27) of these bays (including coastal waters) showed a long-term reduction in alkalinity at a rate of 3.0-21.6 μM yr(-1). Twenty-two bays exhibited pH decreases at a rate of 0.0014-0.0180 yr(-1). In contrast, a northernmost coastal bay exhibited increases in both alkalinity and pH. Overall, the two rates showed a significant positive correlation, indicating that most of these bays, especially those at lower latitudes, have been experiencing long-term acidification. The observed alkalinity decrease may be caused by reduced riverine alkalinity export, a result of precipitation decline under drought conditions, and freshwater diversion for human consumption, as well as calcification in these bays. A decrease in alkalinity inventory and accompanying acidification may have negative impacts on shellfish production in these waters. In addition, subsequent reduction in alkalinity export from these bays to the adjacent coastal ocean may also decrease the buffer capacity of the latter against future acidification.

  2. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, David B.; Lao, Guifang

    1998-01-01

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium.

  3. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, D.B.; Lao, G.

    1998-01-06

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium. 3 figs.

  4. Dietary sucrose enhances intestinal lactase gene expression in euthyroid rats.

    PubMed

    Kuranuki, Sachi; Mochizuki, Kazuki; Goda, Toshinao

    2006-10-01

    It is postulated that dietary carbohydrates and thyroid hormones are major regulators for expression of the lactase/phlorizin hydrolase (LPH) gene in rat jejunum. In this study, we investigated the effects of thyroid hormones and dietary sucrose on LPH gene expression and lactase activity in starved rats. Firstly, animals at 8 wk of age were fed a low-starch diet (5.5% energy as cornstarch) or high-starch diet (71% energy as cornstarch) for 7 d (experiment 1). The mRNA level of LPH as well as lactase activity significantly decreased in rats fed the low-starch diet as compared to those fed the high-starch diet. To investigate the effects of thyroid hormone status, the animals previously fed the low-starch diet were starved for 3 d, and half of the animals were given intraperitoneal (i.p.) injections of 20 microg/ 100 g body weight triiodothyronine (T3) twice daily (experiment 2). The LPH mRNA level and lactase activity were elevated by starvation for 3 d, but they were repressed by the injection of T3 during starvation. To investigate the effects of dietary sucrose in starved rats, they were force-fed a sucrose diet for 6 h (experiment 3). The LPH gene expression and lactase activity were up-regulated by force-feeding a sucrose diet, only when the animals were kept in euthyroid status by daily T3 administrations. In contrast, the sucrase-isomaltase mRNA levels and sucrase activity were unaffected by force-feeding the sucrose diet for both T3-treated and untreated starved rats. Our work suggests that dietary sucrose is capable of enhancing lactase gene expression in starved rats when they have a sustainable thyroid hormone level.

  5. Method for converting sucrose to .beta.-D-glucose

    DOEpatents

    Simmons, Blake A.; Volponi, Joanne V.; Ingersoll, David; Walker, Andrew

    2009-07-07

    Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three-stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

  6. Sucrose: A Prospering and Sustainable Organic Raw Material

    NASA Astrophysics Data System (ADS)

    Peters, Siegfried; Rose, Thomas; Moser, Matthias

    Sucrose (α-d-glucopyranosyl-(1→2)-β-d-fructofuranoside) is an inexpensive chemical produced by sugar cane and sugar beet cultivation. Chemical and/or biochemical transformations convert it into highly valuable synthetic intermediates such as 5-hydroxymethylfurfural (HMF), bioethylene, 1,2-propylene glycol and levulinic acid. Sucrose can also be converted into biodegradable polymers such as polyesters and polyurethanes, as well as into novel carbohydrates such as isomaltulose, trehalulose, inulin, levan, Neo-amylose, and dextran, highly valuable additives for food and cosmetics and materials for separation and purification technologies.

  7. Amperometric biosensors for determination of glucose, maltose, and sucrose

    NASA Astrophysics Data System (ADS)

    Zawicki, Ignacy; Filipiak, Marian; Jarzyna, Marta; Laskowska, Janina

    1995-06-01

    In the presented paper there are reported some results of the author's research on membranes containing glucose oxidase (GOx), enzymes hydrolyzing maltose and sucrose and on biosensors equipped with these membranes. The results relate to ways of extending the linear range of glucose sensors, influence of composition of the membranes on levels of the output signals of maltose and sucrose (saccharose) sensors, temperature dependence of the sensor's response and on disturbing effects of glucose in the sample on accuracy of determination of the disaccharides.

  8. Does sucrose or aspartame cause hyperactivity in children?

    PubMed

    Kanarek, R B

    1994-05-01

    Anecdotal evidence has led to the hypothesis that there is a relationship between sugar intake and hyperactive behavior. To assess this hypothesis, a recent study using a range of behavioral and cognitive measures evaluated the effects of diets high in sucrose, aspartame, and saccharin on the performance of school-aged children believed to be sensitive to sugar, and preschool children. Although intakes exceeded average dietary levels, neither sucrose nor aspartame negatively affected behavior. Taken together with previous work, these results indicate that sugar is not a major cause of hyperactivity.

  9. Anharmonicity and hydrogen bonding in electrooptic sucrose crystal

    NASA Astrophysics Data System (ADS)

    Szostak, M. M.; Giermańska, J.

    1990-03-01

    The polarized absorption spectra of the sucrose crystal in the 5300 - 7300 cm -1 region have been measured. The assignments of all the eight OH stretching overtones are proposed and their mechanical anharmonicities are estimated. The discrepancies from the oriented gas model (OGM) in the observed relative band intensities, especially of the -CH vibrations, are assumed to be connected with vibronic couplings enhanced by the helical arrangement of molecules joined by hydrogen bondings. It seems that this kind of interactions might be important for the second harmonic generation (SHG) by the sucrose crystal.

  10. Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography-mass spectrometry.

    PubMed

    Perrone, Daniel; Donangelo, Carmen Marino; Farah, Adriana

    2008-10-15

    A rapid liquid chromatography-mass spectrometry method for the simultaneous quantification of caffeine, trigonelline, nicotinic acid and sucrose in coffee was developed and validated. The method involved extraction with hot water, clarification with basic lead acetate and membrane filtration, followed by chromatographic separation using a Spherisorb(®) S5 ODS2, 5μm chromatographic column and gradient elution with 0.3% aqueous formic acid/methanol at a flow rate of 0.2mL/min. The electrospray ionization source was operated in the negative mode to generate sucrose ions and in the positive mode to generate caffeine, trigonelline and nicotinic acid ions. Ionization suppression of all analytes was found due to matrix effect. Calibrations curves prepared in green and roasted coffee extracts were linear with r(2)>0.999. Roasted coffee was spiked and recoveries ranged from 93.0% to 105.1% for caffeine, from 85.2% to 116.2% for trigonelline, from 89.6% to 113.5% for nicotinic acid and from 94.1% to 109.7% for sucrose. Good repeatibilities (RSD<5%) were found for all analytes in the matrix. The limit of detection (LOD), calculated on the basis of signal-to-noise ratios of 3:1, was 11.9, 36.4, 18.5 and 5.0ng/mL for caffeine, trigonelline, nicotinic acid and sucrose, respectively. Analysis of 11 coffee samples (regular or decaffeinated green, ground roasted and instant) gave results in agreement with the literature. The method showed to be suitable for different types of coffee available in the market thus appearing as a fast and reliable alternative method to be used for routine coffee analysis. PMID:26047298

  11. Distribution of sucrose around the mouth and its clearance after a sucrose mouthrinse or consumption of three different foods.

    PubMed

    Macpherson, L M; Dawes, C

    1994-01-01

    The distribution of sucrose in whole saliva and in saliva from seven different regions of the mouth was determined in 10 subjects over the 10-min period following the chewing of a doughnut, sucking on a mint candy, the drinking of orange juice, or use of a 10% sucrose mouthrinse. With all products, the sucrose was distributed non-uniformly, with particularly low concentrations on the lingual surfaces of the lower incisors and the facial surfaces of the upper molars. Clearance was also most rapid from these sites. Since the depth and duration of a Stephan curve in dental plaque is influenced by the sugar concentration to which the plaque is exposed, the results, together with previous results on salivary film velocity in different regions of the mouth, help to provide an explanation for the site-specificity of smooth-surface caries and of supragingival calculus deposition. PMID:8033187

  12. The effect of sucrose on unfrozen water and syneresis of acidified sodium caseinate-xanthan gels.

    PubMed

    Braga, A L M; Cunha, R L

    2005-07-01

    The influence of the ingredients of acidified Na caseinate-xanthan-sucrose gels on thermophysical properties and syneresis of the gels was studied. Sucrose concentration affected all of the gel equilibrium properties and the rate of syneresis. The positive effect of sucrose on syneresis and unfrozen water (UFW) values was attributed to different effects. The amount of UFW was governed mainly by the colligative properties of sucrose whereas the equilibrium syneresis behaviour was associated with the changes in network dynamics caused by the kosmotropic properties of sucrose. The latter could enhance xanthan-sucrose association or favour xanthan-protein interactions.

  13. Development of alkaline fuel cells.

    SciTech Connect

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  14. Molecular characterization of sucrose:sucrose 1-fructosyltransferase and sucrose:fructan 6-fructosyltransferase associated with fructan accumulation in winter wheat during cold hardening.

    PubMed

    Kawakami, Akira; Yoshida, Midori

    2002-11-01

    We isolated two cDNAs of winter wheat (Triticum aestivum L.), designated wft1 and wft2, which encoded sucrose:fructan 6-fructosyltransferase (6-SFT) and sucrose:sucrose 1-fructosyltransferase (1-SST; EC 2.4.1.99), respectively, which are involved in the synthesis of fructan in wheat. wft1 and wft2 were cloned by screening of a cDNA library with probed-cDNA fragments corresponding to plant fructosyltransferase and invertase. The identity of the clones was verified by functional characterization of recombinant proteins expressed in methylotrophic yeast, Pichiapastoris. Northern blotting showed that the level of wft2 transcripts increased from autumn to early winter in the crown tissues of all field-grown wheat cultivars examined. Higher levels of wft1 and wft2 transcripts were found in leaf tissues of snow mold-resistant cultivars, which accumulated more fructan than other cultivars. Our results showed that Wft1 and Wft2 were important in fructan accumulation during cold hardening of winter wheat.

  15. Plasmolysis of Escherichia coli B-r with sucrose.

    PubMed

    Scheie, P O

    1969-05-01

    Escherichia coli B/r cells were plasmolyzed in sucrose solutions and observed under phase contrast. The prevalence of plasmolysis under various conditions was noted, and the degree of plasmolysis was categorized as slight, extensive, or severe. The presence of ions reduced the prevalence of plasmolysis. Survival curves showed that extensive plasmolysis was not lethal to colony-forming ability.

  16. Relationships among impurity components, sucrose, and sugarbeet processing quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sodium, potassium, amino-nitrogen, and invert sugar are naturally-occurring constituents of the sugarbeet (Beta vulgaris L.) root, referred to as impurities, which impede sucrose extraction during routine factory operations. Three germplasm lines selected for low sodium, potassium, or amino-nitrogen...

  17. A complete characterization of the vibrational spectra of sucrose.

    PubMed

    Brizuela, Alicia Beatriz; Bichara, Laura Cecilia; Romano, Elida; Yurquina, Alisia; Locatelli, Silvano; Brandán, Silvia Antonia

    2012-11-01

    We combined experimental vibrational spectroscopy (FTIR-Raman) and ab-initio calculations based on density functional theory (DFT) to predict the structural and vibrational properties of sucrose in solid phase. The structural properties of sucrose, such as the bond order, possible charge-transfer, and the topological properties of the glucopyran and glucofuran rings were studied by means of the Natural Bond Orbital (NBO) and Atoms in Molecules theory (AIM) investigation. For a complete assignment of the infrared and Raman spectra, the density functional theory (DFT) calculations were combined with Pulay's Scaled Quantum Mechanics Force Field (SQMFF) methodology in order to fit the theoretical frequency values to the experimental ones. An agreement between theoretical and available experimental results was found. A complete assignment of the 129 normal vibration modes for sucrose was performed. Five very intense characteristic bands in the infrared spectrum of sucrose at 3391, 3339, 1069, 1053, and 991 cm(-1) were assigned, the first two to the OH stretching modes while the other ones to C-O stretching modes. PMID:22878022

  18. Aging and Information Seeking: Patterns in Sampling of Sucrose Solutions.

    ERIC Educational Resources Information Center

    Shapira, N.; Kushnir, T.

    1985-01-01

    Explored age-related strategies of information seeking and decision making. Young and old female participants (N=38) engaged in detecting the presence of sucrose in solutions of various concentrations. Compared to young people, the aged sampled more and had a higher detection threshold, indicating higher requirements for information. (BH)

  19. 21 CFR 172.859 - Sucrose fatty acid esters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sucrose fatty acid esters. 172.859 Section 172.859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... (honeydew and cantaloupe), papaya, peaches, pears, pineapples, and plums to retard ripening and spoiling....

  20. Reducing sucrose loss in sugar beet storage with fungicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Root rots in sugar beet storage can lead to multi-million dollar losses because of reduced sucrose recovery. Thus, studies were conducted to establish better chemical control options and a better understanding of the fungi involved in the rot complex. A water check and three fungicides (Mertect, Pro...

  1. Synthesis of carbon-13 enriched disaccharides: lactose and sucrose

    SciTech Connect

    Walker, T.E.; Unkefer, P.J.; Unkefer, C.J.; Ehler, D.S.

    1986-05-01

    Disaccharides can be prepared enzymatically and by chemical synthesis. Lactose enriched with carbon-13 at C-1 can be synthesized by reacting K/sup 13/CN with a sugar having a one fewer carbon than the desired product. Thus, a mixture of 4-O-..beta..-D-galactopyranosyl-D-(1-/sup 13/C)glucose ((1-/sup 13/C)lactose) and 4-O-..beta..-D-galactopyranosyl-D-(1-/sup 13/C)mannose can be synthesized from 3-O-..beta..-D-galactopyranosyl-D-arabinose and K/sup 13/CN. (/sup 13/C)Sucrose is conveniently prepared in gram quantities from D-(/sup 13/C)fructose and UDP-glucose in a reaction catalyzed by the enzyme sucrose synthetase. This reaction proceeds smoothly at 25/sup 0/ over a period of hours to give an equilibrium mixture which can be separated chromatographically. The glucose portion of sucrose can be labeled using enzymatically-prepared UDP-(/sup 13/C)glucose. Labeled sucrose is important for the preparation of labeled starches to be used for structural and metabolic studies.

  2. Sucrose Responsiveness, Learning Success, and Task Specialization in Ants

    ERIC Educational Resources Information Center

    Perez, Margot; Rolland, Uther; Giurfa,, Martin; d'Ettorre, Patrizia

    2013-01-01

    Social insects possess remarkable learning capabilities, which are crucial for their ecological success. They also exhibit interindividual differences in responsiveness to environmental stimuli, which underlie task specialization and division of labor. Here we investigated for the first time the relationships between sucrose responsiveness,…

  3. Regulation of sucrose synthesis in water stressed leaves

    SciTech Connect

    Daie, J.; Aloni, B. )

    1991-05-01

    Alteration in carbon metabolism and carbohydrate partitioning occur in drought stressed plants. Some species accumulate large quantities of starch in the chloroplast, which may be used to support sucrose synthesis under conditions of limited carbon supply. The authors monitored chemical partitioning of carbon between sugars and starch and the activity of sucrose phosphate synthase (SPS) and fructose 1,6 bisphosphatase (FBPase) in the source leaves of water stressed tomatoes. Plants were stressed by withdrawing water for 10 days and rewatered for recovery. Water potential dropped from {minus}0.8 to {minus}2.2MPA in 10 days, but recovered to control level 2 days after rewatering. Photosynthetic rates as measured by the activity of Rubisco followed similar patterns to those of water potential. After 10 days, leaf starch levels decreased to less than 50% of control. Sucrose levels did not increase significantly, but hexose levels increased 3-4 fold during the stress period, and decreased to control levels 1 day after rewatering. FBPase activity decreased and SPS activity increased under stress conditions. Upon rewatering, the activity of FBPase and SPS returned to control levels. Presence of large quantities of hexose and activation of SPS in stressed leaves suggested that additional sucrose synthesized under stress was hydrolyzed to hexoses, presumably due to enhanced invertase activity.

  4. [Importance of sucrose in cognitive functions: knowledge and behavior].

    PubMed

    Zamora Navarro, Salvador; Pérez Llamas, Francisca

    2013-07-01

    Sucrose is not present in the internal milieu as such, so it is physically impossible that it may have a direct influence on cognitive functions, behaviour and knowledge. However, during the digestive process, disaccharides are released into monosaccharides, in the case of sucrose into glucose and fructose, which reach the liver via the portal vein. Finally, they go into bloodstream in the form of glucose and in some cases as very low-density lipoproteins (VLDL). Brain needs almost exclusively a constant supply of glucose from the bloodstream. Adult brain requires about 140 g of glucose per day, which represents up to a 50% of total carbohydrates consumed daily in the diet. The consumption of a food or beverage enriched with sucrose has been associated with improved mental alertness, memory, reaction time, attention and ability to solve mathematical problems, as well as a reduction in the feeling of fatigue, both in healthy individuals and patients with Alzheimer disease. An adequate nutrition of brain contributes to structural and functional integrity of neurons. It has been shown that in major mental illnesses such as schizophrenia, depression and Alzheimer's disease, nutritional deficiencies at cellular level are implicated. At present, several studies highlight the need to improve understanding of the processes involved in the deterioration of cognitive functions and mechanisms through which, the nutritive components of the diet, particularly the sucrose, may modulate such functions.

  5. Sucrose in the dynamics of the carious process.

    PubMed

    Newbrun, E

    1982-03-01

    The conclusion that sugar consumption and caries are related is inescapable. Studies of the dynamics of sucrose metabolism by cariogenic organisms, investigations of experimental caries in animals and clinical observations of the inter-relationship of dietary sucrose intake and caries experience all provide compelling evidence that the proportion of sucrose in a food is one important determinant of its cariogenicity. Accordingly, better labelling of foods and beverages to disclose the concentration (percentage by weight or volume) of sucrose and other sugars would help consumers in choosing products less likely to cause caries. Journals, particularly professional ones, should refrain from publishing potentially misleading or distorted advertisements concerning foods. Because of the multifactorial nature of caries aetiology, the fact that humans eat a mixed diet and evidence that the sequence of eating various foods may affect their cariogenic potential, it is most unlikely that any one test of cariogenicity could be reliable. It may be possible to use a combination of tests to gain meaningful information on the cariogenicity of foods.

  6. Effects of sucrose ingestion on the behavior of hyperactive boys.

    PubMed

    Wolraich, M; Milich, R; Stumbo, P; Schultz, F

    1985-04-01

    A challenge design was used in two separate studies to investigate the effects of sucrose ingestion on the behavior and learning of hyperactive boys. In both studies, 16 boys were admitted to a clinical research center for 3 successive days, on each of which they were given a sucrose-free diet. On day 1, baseline levels on the learning tasks were established; on days 2 and 3 a challenge drink of either sucrose 1.75 gm/kg or a placebo (aspartame in equivalent sweetness) was presented, in a counterbalanced order. In the first study the challenge drink was administered 1 hour after lunch; in the second study it was given in the morning after an overnight fast. On days 2 and 3 of both studies, 37 behavioral (playroom observation and examiner ratings) and cognitive (learning and memory tasks) measures were collected, starting 1/2 hour after ingestion of the drink. The results of both studies revealed no differences between the boys' performance on the two challenge days. These findings undermine the hypothesis that sucrose plays a major role in accounting for the inappropriate behavior of hyperactive boys.

  7. Alkalinization by chloride/bicarbonate pathway in larval mosquito midgut

    PubMed Central

    Boudko, Dmitri Y.; Moroz, Leonid L.; Harvey, William R.; Linser, Paul J.

    2001-01-01

    The midgut of mosquito larvae maintains a specific lumen alkalinization profile with large longitudinal gradients (pH ≈ 3 units⋅mm−1) in which an extremely alkaline (pH ≈ 11) anterior midgut lies between near-neutral posterior midgut and gastric cecum (pH 7–8). A plasma membrane H+ V-ATPase energizes this alkalinization but the ion carriers involved are unknown. Capillary zone electrophoresis of body samples with outlet conductivity detection showed a specific transepithelial distribution of chloride and bicarbonate/carbonate ions, with high concentrations of both anions in the midgut tissue: 68.3 ± 5.64 and 50.8 ± 4.21 mM, respectively. Chloride was higher in the hemolymph, 57.6 ± 7.84, than in the lumen, 3.51 ± 2.58, whereas bicarbonate was higher in the lumen, 58.1 ± 7.34, than the hemolymph, 3.96 ± 2.89. Time-lapse video assays of pH profiles in vivo revealed that ingestion of the carbonic anhydrase inhibitor acetazolamide and the ion exchange inhibitor DIDS (4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid), at 10−4 M eliminates lumen alkalinization. Basal application of these inhibitors in situ also reduced gradients recorded with self-referencing pH-sensitive microelectrodes near the basal membrane by ≈65% and 85% respectively. Self-referencing chloride-selective microelectrodes revealed a specific spatial profile of transepithelial chloride transport with an efflux maximum in anterior midgut. Both acetazolamide and DIDS reduced chloride effluxes. These data suggest that an H+ V-ATPase-energized anion exchange occurs across the apical membrane of the epithelial cells and implicate an electrophoretic Cl−/HCO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{3}^{-}}}\\end{equation*}\\end{document} exchanger and carbonic anhydrase as

  8. Use of sodium dodecyl sulfate-polymyxin B-sucrose medium for isolation of Vibrio vulnificus from shellfish.

    PubMed

    Bryant, R G; Jarvis, J; Janda, J M

    1987-07-01

    The differential and selective sodium dodecyl sulfate-polymyxin B-sucrose medium (SPS) of Kitaura et al. (T. Kitaura, S. Doke, I. Azuma, M. Imaida, K. Miyano, K. Harada, and E. Yabuuchii, FEMS Microbiol. Lett. 17:205-209, 1983), which highlights alkylsulfatase activity, was evaluated for its potential use in the direct isolation and enumeration of Vibrio vulnificus from shellfish. V. vulnificus was detected by this method in six of nine shellfish samples collected from diverse geographic locales during the summer of 1986. Direct enumeration of V. vulnificus at 7.0 X 10(2) to 2.2 X 10(4) CFU/g of shellfish was achieved on SPS agar. All sample results were confirmed in parallel examinations by using conventional glucose-salt-Teepol (Shell Oil Co.) broth and alkaline peptone water enrichment with plating onto thiosulfate-citrate-bile salts-sucrose agar. Additionally, alkylsulfatase activity was evaluated in vitro for 97 strains representing 14 Vibrio spp. V. vulnificus and Vibrio cholerae-01 were the only species consistently found to possess this activity. The range of plating efficiencies for random V. vulnificus strains analyzed on SPS was 11 to 74% (mean, 39%). The use of SPS shows great promise for the study of shellfish and other environmental sources for V. vulnificus. PMID:3662506

  9. Use of sodium dodecyl sulfate-polymyxin B-sucrose medium for isolation of Vibrio vulnificus from shellfish.

    PubMed

    Bryant, R G; Jarvis, J; Janda, J M

    1987-07-01

    The differential and selective sodium dodecyl sulfate-polymyxin B-sucrose medium (SPS) of Kitaura et al. (T. Kitaura, S. Doke, I. Azuma, M. Imaida, K. Miyano, K. Harada, and E. Yabuuchii, FEMS Microbiol. Lett. 17:205-209, 1983), which highlights alkylsulfatase activity, was evaluated for its potential use in the direct isolation and enumeration of Vibrio vulnificus from shellfish. V. vulnificus was detected by this method in six of nine shellfish samples collected from diverse geographic locales during the summer of 1986. Direct enumeration of V. vulnificus at 7.0 X 10(2) to 2.2 X 10(4) CFU/g of shellfish was achieved on SPS agar. All sample results were confirmed in parallel examinations by using conventional glucose-salt-Teepol (Shell Oil Co.) broth and alkaline peptone water enrichment with plating onto thiosulfate-citrate-bile salts-sucrose agar. Additionally, alkylsulfatase activity was evaluated in vitro for 97 strains representing 14 Vibrio spp. V. vulnificus and Vibrio cholerae-01 were the only species consistently found to possess this activity. The range of plating efficiencies for random V. vulnificus strains analyzed on SPS was 11 to 74% (mean, 39%). The use of SPS shows great promise for the study of shellfish and other environmental sources for V. vulnificus.

  10. New insight into the catalytic properties of rice sucrose synthase.

    PubMed

    Huang, Yu-Chiao; Hsiang, Erh-Chieh; Yang, Chien-Chih; Wang, Ai-Yu

    2016-01-01

    Sucrose synthase (SuS), which catalyzes the reversible conversion of sucrose and uridine diphosphate (UDP) into fructose and UDP-glucose, is a key enzyme in sucrose metabolism in higher plants. SuS belongs to family 4 of the glycosyltransferases (GT4) and contains an E-X7-E motif that is conserved in members of GT4 and two other GT families. To gain insight into the roles of this motif in rice sucrose synthase 3 (RSuS3), the two conserved glutamate residues (E678 and E686) in this motif and a phenylalanine residue (F680) that resides between the two glutamate residues were changed by site-directed mutagenesis. All mutant proteins maintained their tetrameric conformation. The mutants E686D and F680Y retained partial enzymatic activity and the mutants E678D, E678Q, F680S, and E686Q were inactive. Substrate binding assays indicated that UDP and fructose, respectively, were the leading substrates in the sucrose degradation and synthesis reactions of RSuS3. Mutations on E678, F680, and E686 affected the binding of fructose, but not of UDP. The results indicated that E678, F680, and E686 in the E-X7-E motif of RSuS3 are essential for the activity of the enzyme and the sequential binding of substrates. The sequential binding of the substrates implied that the reaction catalyzed by RSuS can be controlled by the availability of fructose and UDP, depending on the metabolic status of a tissue.

  11. Sucrose Diffusion in Decellularized Heart Valves for Freeze-Drying.

    PubMed

    Wang, Shangping; Oldenhof, Harriëtte; Goecke, Tobias; Ramm, Robert; Harder, Michael; Haverich, Axel; Hilfiker, Andres; Wolkers, Willem Frederik

    2015-09-01

    Decellularized heart valves can be used as starter matrix implants for heart valve replacement therapies in terms of guided tissue regeneration. Decellularized matrices ideally need to be long-term storable to assure off-the-shelf availability. Freeze-drying is an attractive preservation method, allowing storage at room temperature in a dried state. However, the two inherent processing steps, freezing and drying, can cause severe damage to extracellular matrix (ECM) proteins and the overall tissue histoarchitecture and thus impair biomechanical characteristics of resulting matrices. Freeze-drying therefore requires a lyoprotective agent that stabilizes endogenous structural proteins during both substeps and that forms a protective glassy state at room temperature. To estimate incubation times needed to infiltrate decellularized heart valves with the lyoprotectant sucrose, temperature-dependent diffusion studies were done using Fourier transform infrared spectroscopy. Glycerol, a cryoprotective agent, was studied for comparison. Diffusion of both protectants was found to exhibit Arrhenius behavior. The activation energies of sucrose and glycerol diffusion were found to be 15.9 and 37.7 kJ·mol(-1), respectively. It was estimated that 4 h of incubation at 37°C is sufficient to infiltrate heart valves with sucrose before freeze-drying. Application of a 5% sucrose solution was shown to stabilize acellular valve scaffolds during freeze-drying. Such freeze-dried tissues, however, displayed pores, which were attributed to ice crystal damage, whereas vacuum-dried scaffolds in comparison revealed no pores after drying and rehydration. Exposure to a hygroscopic sucrose solution (80%) before freeze-drying was shown to be an effective method to diminish pore formation in freeze-dried ECMs: matrix structures closely resembled those of control samples that were not freeze-dried. Heart valve matrices were shown to be in a glassy state after drying, suggesting that they can

  12. Sucrose Diffusion in Decellularized Heart Valves for Freeze-Drying.

    PubMed

    Wang, Shangping; Oldenhof, Harriëtte; Goecke, Tobias; Ramm, Robert; Harder, Michael; Haverich, Axel; Hilfiker, Andres; Wolkers, Willem Frederik

    2015-09-01

    Decellularized heart valves can be used as starter matrix implants for heart valve replacement therapies in terms of guided tissue regeneration. Decellularized matrices ideally need to be long-term storable to assure off-the-shelf availability. Freeze-drying is an attractive preservation method, allowing storage at room temperature in a dried state. However, the two inherent processing steps, freezing and drying, can cause severe damage to extracellular matrix (ECM) proteins and the overall tissue histoarchitecture and thus impair biomechanical characteristics of resulting matrices. Freeze-drying therefore requires a lyoprotective agent that stabilizes endogenous structural proteins during both substeps and that forms a protective glassy state at room temperature. To estimate incubation times needed to infiltrate decellularized heart valves with the lyoprotectant sucrose, temperature-dependent diffusion studies were done using Fourier transform infrared spectroscopy. Glycerol, a cryoprotective agent, was studied for comparison. Diffusion of both protectants was found to exhibit Arrhenius behavior. The activation energies of sucrose and glycerol diffusion were found to be 15.9 and 37.7 kJ·mol(-1), respectively. It was estimated that 4 h of incubation at 37°C is sufficient to infiltrate heart valves with sucrose before freeze-drying. Application of a 5% sucrose solution was shown to stabilize acellular valve scaffolds during freeze-drying. Such freeze-dried tissues, however, displayed pores, which were attributed to ice crystal damage, whereas vacuum-dried scaffolds in comparison revealed no pores after drying and rehydration. Exposure to a hygroscopic sucrose solution (80%) before freeze-drying was shown to be an effective method to diminish pore formation in freeze-dried ECMs: matrix structures closely resembled those of control samples that were not freeze-dried. Heart valve matrices were shown to be in a glassy state after drying, suggesting that they can

  13. Sucrose substitutes affect the cariogenic potential of Streptococcus mutans biofilms.

    PubMed

    Durso, S C; Vieira, L M; Cruz, J N S; Azevedo, C S; Rodrigues, P H; Simionato, M R L

    2014-01-01

    Streptococcus mutans is considered the primary etiologic agent of dental caries and contributes significantly to the virulence of dental plaque, especially in the presence of sucrose. To avoid the role of sucrose on the virulence factors of S. mutans, sugar substitutes are commonly consumed because they lead to lower or no production of acids and interfere with biofilm formation. This study aimed to investigate the contribution of sugar substitutes in the cariogenic potential of S. mutans biofilms. Thus, in the presence of sucrose, glucose, sucralose and sorbitol, the biofilm mass was quantified up to 96 h, the pH of the spent culture media was measured, the expression of biofilm-related genes was determined, and demineralization challenge experiments were conduct in enamel fragments. The presence of sugars or sugar substitutes profoundly affected the expression of spaP, gtfB, gtfC, gbpB, ftf, vicR and vicX in either biofilm or planktonic cells. The substitution of sucrose induced a down-regulation of most genes involved in sucrose-dependent colonization in biofilm cells. When the ratio between the expression of biofilm and planktonic cells was considered, most of those genes were down-regulated in biofilm cells in the presence of sugars and up-regulated in the presence of sugar substitutes. However, sucralose but not sorbitol fulfilled the purpose of reducing the cariogenic potential of the diet since it induced the biofilm formation with the lowest biomass, did not change the pH of the medium and led to the lowest lesion depth in the cariogenic challenge.

  14. The Path of Carbon in Photosynthesis XIX. The Identification of Sucrose Phosphate in Sugar Beet Leaves

    DOE R&D Accomplishments Database

    Buchanan, J. G.

    1952-09-01

    The recognition and characterization of a sucrose phosphate as an intermediate in sucrose by synthesis by green plants is described. A tentative structure for this phosphate is proposed and its mode of formation suggested.

  15. The opioid system majorly contributes to preference for fat emulsions but not sucrose solutions in mice.

    PubMed

    Sakamoto, Kazuhiro; Okahashi, Tatsuya; Matsumura, Shigenobu; Okafuji, Yoko; Adachi, Shin-ichi; Tsuzuki, Satoshi; Inoue, Kazuo; Fushiki, Tohru

    2015-01-01

    Rodents show a stronger preference for fat than sucrose, even if their diet is isocaloric. This implies that the preference mechanisms for fat and sucrose differ. To compare the contribution of the opioid system to the preference of fat and sucrose, we examined the effects of mu-, delta-, kappa-, and non-selective opioid receptor antagonists on the preference of sucrose and fat, assessed by a two-bottle choice test and a licking test, in mice naïve to sucrose and fat ingestion. Administration of non-selective and mu-selective opioid receptor antagonists more strongly inhibited the preference of fat than sucrose. While the preference of fat was reduced to the same level as water by the antagonist administration that of sucrose was still greater than water. Our results suggest that the preference of fat relies strongly on the opioid system, while that of sucrose is regulated by other mechanisms in addition to the opioid system.

  16. Overexpression of sucrose transporter gene PbSUT2 from Pyrus bretschneideri, enhances sucrose content in Solanum lycopersicum fruit.

    PubMed

    Wang, Li-Fen; Qi, Xiao-Xiao; Huang, Xiao-San; Xu, Lin-Lin; Jin, Cong; Wu, Jun; Zhang, Shao-Ling

    2016-08-01

    Sucrose transporters (SUTs) belong to the major facilitator superfamily. The function of SUTs has been intensively investigated in some higher plants, whereas that in pear fruit is unknown. In this study, the cloning and functional characterization of a sucrose transporter, PbSUT2, in pear (Pyrus bretschneideri Rehd. cv. 'Yali') fruits are reported. PbSUT2 encoded a protein of 498 amino acid residues, and was localized in the plasma membrane of transformed onion epidermal cells and Arabidopsis protoplasts. Phylogenetic analysis revealed that PbSUT2 belonged to the SUT4 clade. The phenotype of overexpression of PbSUT2 tomato plants included early flowering, higher fruit quantity and lower plant height. Overexpression of PbSUT2 in transgenic tomato plants led to increases in the net photosynthetic rate in leaves and sucrose content in mature fruit compared with wild-type tomato plants, and a decrease in the contents of glucose, fructose and total soluble sugars in mature fruits. These results suggested that PbSUT2 affected sucrose content in sinks and the flowering phase during tomato plant growth and development. PMID:27105422

  17. Transgene silencing of sucrose synthase in alfalfa stem vascular tissue by a truncated phosphoenolpyruvate carboxylase: sucrose synthase construct

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An important role of sucrose synthase (SUS, EC 2.4.1.13) in plants is to provide UDP-glucose needed for cellulose synthesis in cell walls. We examined if over-expressing SUS in alfalfa (Medicago sativa L.) would increase cellulose content of stem cell walls. Alfalfa plants were transformed with two ...

  18. Laser textured surface gradients

    NASA Astrophysics Data System (ADS)

    Ta, Van Duong; Dunn, Andrew; Wasley, Thomas J.; Li, Ji; Kay, Robert W.; Stringer, Jonathan; Smith, Patrick J.; Esenturk, Emre; Connaughton, Colm; Shephard, Jonathan D.

    2016-05-01

    This work demonstrates a novel technique for fabricating surfaces with roughness and wettability gradients and their subsequent applications for chemical sensors. Surface roughness gradients on brass sheets are obtained directly by nanosecond laser texturing. When these structured surfaces are exposed to air, their wettability decreases with time (up to 20 days) achieving both spatial and temporal wettability gradients. The surfaces are responsive to organic solvents. Contact angles of a series of dilute isopropanol solutions decay exponentially with concentration. In particular, a fall of 132° in contact angle is observed on a surface gradient, one order of magnitude higher than the 14° observed for the unprocessed surface, when the isopropanol concentration increased from 0 to 15.6 wt%. As the wettability changes gradually over the surface, contact angle also changes correspondingly. This effect offers multi-sensitivity at different zones on the surface and is useful for accurate measurement of chemical concentration.

  19. pH gradients induced by urea metabolism in 'artificial mouth' microcosm plaques.

    PubMed

    Sissons, C H; Wong, L; Hancock, E M; Cutress, T W

    1994-06-01

    Evidence was sought for urea-induced pH gradients in dental plaque microcosm biofilms cultured from the mixed salivary bacteria in a multi plaque 'artificial mouth'. Application of 500 mmol/l urea for short periods (6 min) to 5-8 mm maximum-thickness plaques induced intraplaque pH gradients of up to 0.7 pH units with the surface alkaline relative to the inner plaque. These pH gradients persisted for more than 5 h in the absence of a flow of fluid. With 30-min urea applications and a flow of a basal medium containing mucin (BMM, pH 7.0), the pH of the inner (deeper) plaque regions also increased. Although the pH gradient initially formed was alkaline at the plaque surface, the BMM flow lowered the surface pH to neutrality whilst the inner layers were still alkaline, thereby reversing the pH gradient. In thick microcosm dental plaques, urea-induced pH gradients can therefore form and last many hours. They probably result from the significant time taken for urea to penetrate to the inner layers of plaque, its rapid metabolism by the outer plaque layers, and a rate-limiting clearance of ammonia. Even a slow BMM flow over the plaque greatly increased the rate of return to the resting pH, causing the gradients to change polarity.

  20. Assessment of Sugar Components and Genes Involved in the Regulation of Sucrose Accumulation in Peach Fruit.

    PubMed

    Vimolmangkang, Sornkanok; Zheng, Hongyu; Peng, Qian; Jiang, Quan; Wang, Huiliang; Fang, Ting; Liao, Liao; Wang, Lu; He, Huaping; Han, Yuepeng

    2016-09-01

    Soluble sugar contents in mature fruits of 45 peach accessions were quantified using gas chromatography analysis. Sucrose is the predominant sugar in mature fruit, followed by glucose and fructose, which have similar concentrations. Overall, sucrose metabolism and accumulation are crucial determinants of sugar content in peach fruit, and there is a wide range of sucrose concentrations among peach genotypes. To understand the mechanisms regulating sucrose accumulation in peach fruit, expression profiles of genes involved in sucrose metabolism and transport were compared among four genotypes. Two sucrose-cleaving enzyme genes (SUS4 and NINV8), one gene involved in sucrose resynthesis (SPS3), and three sugar transporter genes (SUT2, SUT4, and TMT2) were prevalently expressed in peach fruit, and their expression levels are significantly correlated with sucrose accumulation. In contrast, the VAINV genes responsible for sucrose cleavage in the vacuole were weakly expressed in mature fruit, suggesting that the sucrose-cleaving reaction is not active in the vacuole of sink cells of mature peach fruit. This study suggests that sucrose accumulation in peach fruit involves the coordinated interaction of genes related to sucrose cleavage, resynthesis, and transport, which could be helpful for future peach breeding. PMID:27537219

  1. Aspects of sucrose transport in stem parenchyma of sweet sorghum. [Sorghum bicolor

    SciTech Connect

    Lingle, S.E.

    1987-08-01

    Sweet sorghum (Sorghum bicolor (L.) Moench) is a sucrose-storing crop with a storage tissue anatomically similar to that of sugarcane (Saccharum spp.). However, recent evidence suggests that sweet sorghum may be biochemically different from sugarcane. /sup 14/C-sucrose uptake was studied in excised tissue discs from fully-elongated internodes of Rio sweet sorghum. Washout studies gave results consistent with a 3 compartment system. After 3 hours of uptake, most of the /sup 14/C was found in the vacuole compartment, and was determined by HPLC to be sucrose. Total sucrose uptake consisted of a PCMBS-sensitive (active) and a PCMBS-insensitive (passive) component. Active sucrose uptake had a pH optimum of 4.5. Total sucrose uptake was negatively correlated with the internal sucrose content of the tissue. Fructosyl-labelled /sup 14/C-sucrose was not randomized during uptake, suggesting that sucrose cleavage is not a requirement for sucrose uptake in sweet sorghum. This data suggests that in sweet sorghum, sucrose is transported intact by a specific carrier, as opposed to the sucrose-cleavage-and-resynthesis transport system that apparently operates in sugarcane.

  2. Reinforcement Value and Substitutability of Sucrose and Wheel Running: Implications for Activity Anorexia

    ERIC Educational Resources Information Center

    Belke, Terry W.; Duncan, Ian D.; Pierce, W. David

    2006-01-01

    Choice between sucrose and wheel-running reinforcement was assessed in two experiments. In the first experiment, ten male Wistar rats were exposed to concurrent VI 30 s VI 30 s schedules of wheel-running and sucrose reinforcement. Sucrose concentration varied across concentrations of 2.5, 7.5, and 12.5%. As concentration increased, more behavior…

  3. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  4. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more than two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  5. Chemical nature of alkaline polyphosphate boundary film at heated rubbing surfaces

    NASA Astrophysics Data System (ADS)

    Wan, Shanhong; Tieu, A. Kiet; Zhu, Qiang; Zhu, Hongtao; Cui, Shaogang; Mitchell, David R. G.; Kong, Charlie; Cowie, Bruce; Denman, John A.; Liu, Rong

    2016-05-01

    Alkaline polyphosphate has been demonstrated to be able to reduce significant wear and friction of sliding interfaces under heavy loads (>1 GPa) and elevated temperature (800 °C and above) conditions, e.g. hot metal manufacturing. The chemical composition and fine structure of polyphosphate lubricating film is not well understood as well as the role of alkaline elements within the reaction film at hot rubbing surface. This work makes use of the coupling surface analytical techniques on the alkaline polyphosphate tribofilm, XANES, TOF-SIMS and FIB/TEM. The data show the composition in gradient distribution and trilaminar structure of tribofilm: a shorter chain phosphate overlying a long chain polyphosphate that adheres onto oxide steel base through a short chain phosphate. The chemical hardness model well explains the anti-abrasive mechanism of alkaline polyphosphate at elevated temperatures and also predicts a depolymerisation and simultaneous cross-linking of the polyphosphate glass. The role of alkaline elements in the lubrication mechanism is especially explained. This work firstly serves as a basis for a detailed study of alkaline polyphosphate tribofilm at temperature over 600 °C.

  6. Chemical nature of alkaline polyphosphate boundary film at heated rubbing surfaces

    PubMed Central

    Wan, Shanhong; Tieu, A. Kiet; Zhu, Qiang; Zhu, Hongtao; Cui, Shaogang; Mitchell, David R. G.; Kong, Charlie; Cowie, Bruce; Denman, John A.; Liu, Rong

    2016-01-01

    Alkaline polyphosphate has been demonstrated to be able to reduce significant wear and friction of sliding interfaces under heavy loads (>1 GPa) and elevated temperature (800 °C and above) conditions, e.g. hot metal manufacturing. The chemical composition and fine structure of polyphosphate lubricating film is not well understood as well as the role of alkaline elements within the reaction film at hot rubbing surface. This work makes use of the coupling surface analytical techniques on the alkaline polyphosphate tribofilm, XANES, TOF-SIMS and FIB/TEM. The data show the composition in gradient distribution and trilaminar structure of tribofilm: a shorter chain phosphate overlying a long chain polyphosphate that adheres onto oxide steel base through a short chain phosphate. The chemical hardness model well explains the anti-abrasive mechanism of alkaline polyphosphate at elevated temperatures and also predicts a depolymerisation and simultaneous cross-linking of the polyphosphate glass. The role of alkaline elements in the lubrication mechanism is especially explained. This work firstly serves as a basis for a detailed study of alkaline polyphosphate tribofilm at temperature over 600 °C. PMID:27180956

  7. Chemical nature of alkaline polyphosphate boundary film at heated rubbing surfaces.

    PubMed

    Wan, Shanhong; Tieu, A Kiet; Zhu, Qiang; Zhu, Hongtao; Cui, Shaogang; Mitchell, David R G; Kong, Charlie; Cowie, Bruce; Denman, John A; Liu, Rong

    2016-01-01

    Alkaline polyphosphate has been demonstrated to be able to reduce significant wear and friction of sliding interfaces under heavy loads (>1 GPa) and elevated temperature (800 °C and above) conditions, e.g. hot metal manufacturing. The chemical composition and fine structure of polyphosphate lubricating film is not well understood as well as the role of alkaline elements within the reaction film at hot rubbing surface. This work makes use of the coupling surface analytical techniques on the alkaline polyphosphate tribofilm, XANES, TOF-SIMS and FIB/TEM. The data show the composition in gradient distribution and trilaminar structure of tribofilm: a shorter chain phosphate overlying a long chain polyphosphate that adheres onto oxide steel base through a short chain phosphate. The chemical hardness model well explains the anti-abrasive mechanism of alkaline polyphosphate at elevated temperatures and also predicts a depolymerisation and simultaneous cross-linking of the polyphosphate glass. The role of alkaline elements in the lubrication mechanism is especially explained. This work firstly serves as a basis for a detailed study of alkaline polyphosphate tribofilm at temperature over 600 °C. PMID:27180956

  8. Bovine splenic nerve: characterization of noradrenaline-containing vesicles and other cell organelles by density gradient centrifugation

    PubMed Central

    Hörtnagl, H.; Hörtnagl, Heide; Winkler, H.

    1969-01-01

    1. Homogenates of bovine splenic nerves were subjected to differential and sucrose density gradient centrifugation. From the low-speed supernatant a high-speed sediment (mitochondria, lysosomes, microsomes and noradrenaline (NA) vesicles) was obtained. By density gradient centrifugation of this sediment it was shown that NA vesicles are slightly less dense than mitochondria, but denser than microsomes. 2. In further experiments a mitochondrial and a microsomal sediment were obtained. The mitochondrial sediment was fractionated with a short centrifugation time over a density gradient ranging from 0·6 to 1·2 M sucrose. Mitochondria (fumarase and succinate-dehydrogenase) and lysosomes (acid ribonuclease and deoxyribonuclease) sedimented to the bottom of the tube. The highest concentration of NA vesicles was found in a medium position. There was only a small amount of microsomes (glucose-6-phosphatase) present. 3. The microsomal sediment was centrifuged for 150 min over a density gradient ranging from 0·8 to 1·4 M sucrose. The microsomes remained on the top of the gradient. There were also some mitochondria and lysosomes present. The NA vesicles were found in highest concentration in the middle of the gradient (at about 1·2 M sucrose). 4. With the use of these two density gradients, the subcellular distribution of dopamine-β-hydroxylase, monoamine oxidase and ATPase was studied. Dopamine-β-hydroxylase was found to be localized in the NA vesicles. Monoamine oxidase was mainly recovered in mitochondria; a small part of the enzyme appeared to be microsomal. ATPase was present in microsomal elements. PMID:4310509

  9. Alkaline Water and Longevity: A Murine Study.

    PubMed

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of "deceleration aging factor" as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models.

  10. Alkaline detergent recycling via ultrafiltration

    SciTech Connect

    Steffani, C.; Meltzer, M.

    1995-06-01

    The metal finishing industry uses alkaline cleaners and detergents to remove oils and dirt from manufactured parts, often before they are painted or plated. The use of these cleaners has grown because environmental regulations are phasing out ozone depleting substances and placing restrictions on the use and disposal of many hazardous solvents. Lawrence Livermore National Laboratory is examining ultrafiltration as a cleaning approach that reclaims the cleaning solutions and minimizes wastes. The ultrafiltration membrane is made from sheets of polymerized organic film. The sheets are rolled onto a supporting frame and installed in a tube. Spent cleaning solution is pumped into a filter chamber and filtered through the membrane that captures oils and dirt and allows water and detergent to pass. The membrane is monitored and when pressure builds from oil and dirt, an automatic system cleans the surface to maintain solution flow and filtration quality. The results show that the ultrafiltration does not disturb the detergent concentration or alkalinity but removed almost all the oils and dirt leaving the solution in condition to be reused.

  11. Grace DAKASEP alkaline battery separator

    NASA Technical Reports Server (NTRS)

    Giovannoni, R. T.; Lundquist, J. T.; Choi, W. M.

    1987-01-01

    The Grace DAKASEP separator was originally developed as a wicking layer for nickel-zinc alkaline batteries. The DAKASEP is a filled non-woven separator which is flexible and heat sealable. Through modification of formulation and processing variables, products with a variety of properties can be produced. Variations of DAKASEP were tested in Ni-H2, Ni-Zn, Ni-Cd, and primary alkaline batteries with good results. The properties of DAKASEP which are optimized for Hg-Zn primary batteries are shown in tabular form. This separator has high tensile strength, 12 micron average pore size, relatively low porosity at 46-48 percent, and consequently moderately high resistivity. Versions were produced with greater than 70 percent porosity and resistivities in 33 wt percent KOH as low as 3 ohm cm. Performance data for Hg-Zn E-1 size cells containing DAKASEP with the properties shown in tabular form, are more reproducible than data obtained with a competitive polypropylene non-woven separator. In addition, utilization of active material is in general considerably improved.

  12. The design of alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Strasser, K.

    1990-01-01

    Alkaline fuel cells recently developed have yielded satisfactory operation even in the cases of their use of mobile and matrix-type electrolytes; the advantages of realistic operation have been demonstrated by a major West German manufacturer's 100 kW alkaline fuel cell apparatus, which was operated in the role of an air-independent propulsion system. Development has begun for a spacecraft alkaline fuel cell of the matrix-electrolyte configuration.

  13. Dopaminergic modulation of sucrose acceptance behavior in Drosophila.

    PubMed

    Marella, Sunanda; Mann, Kevin; Scott, Kristin

    2012-03-01

    For an animal to survive in a constantly changing environment, its behavior must be shaped by the complex milieu of sensory stimuli it detects, its previous experience, and its internal state. Although taste behaviors in the fly are relatively simple, with sugars eliciting acceptance behavior and bitter compounds avoidance, these behaviors are also plastic and are modified by intrinsic and extrinsic cues, such as hunger and sensory stimuli. Here, we show that dopamine modulates a simple taste behavior, proboscis extension to sucrose. Conditional silencing of dopaminergic neurons reduces proboscis extension probability, and increased activation of dopaminergic neurons increases extension to sucrose, but not to bitter compounds or water. One dopaminergic neuron with extensive branching in the primary taste relay, the subesophageal ganglion, triggers proboscis extension, and its activity is altered by satiety state. These studies demonstrate the marked specificity of dopamine signaling and provide a foundation to examine neural mechanisms of feeding modulation in the fly. PMID:22405204

  14. Sucrose solution freezing studied by magnetic resonance imaging.

    PubMed

    Mahdjoub, Rachid; Chouvenc, Pierre; Seurin, Marie José; Andrieu, Julien; Briguet, André

    2006-03-20

    Ice formation of a 20% w/v sucrose solution was monitored during the freezing process by magnetic resonance imaging (MRI). An original experimental setup was designed with oil as a cooling fluid that allows accurate control of the temperature. The NMR signal intensity of particular sampled volumes was observed during the entire cooling period, from 0 to -50 degrees C, showing a peak characteristic to a transition before the loss of the signal. Moreover, spatial ice distribution of the frozen matrix was observed by high resolution MRI with an isotropic resolution of 78x78x78microm(3). MRI has proved to be a novel technique for determining the glass transition temperature of frozen sucrose solutions, in the concentration range where calorimetric measurements are not feasible. PMID:16430876

  15. Dopaminergic modulation of sucrose acceptance behavior in Drosophila

    PubMed Central

    Marella, Sunanda; Mann, Kevin; Scott, Kristin

    2012-01-01

    For an animal to survive in a constantly changing environment, its behavior must be shaped by the complex milieu of sensory stimuli it detects, its previous experience and its internal state. Although taste behaviors in the fly are relatively simple, with sugars eliciting acceptance behavior and bitter compounds avoidance, these behaviors are also plastic and modified by intrinsic and extrinsic cues such as hunger and sensory stimuli. Here, we show that dopamine modulates a simple taste behavior, proboscis extension to sucrose. Conditional silencing of dopaminergic neurons reduces proboscis extension probability and increased activation of dopaminergic neurons increases extension to sucrose but not to bitter compounds or water. One dopaminergic neuron with extensive branching in the primary taste relay, the subesophageal ganglion, triggers proboscis extension and its activity is altered by satiety state. These studies demonstrate the marked specificity of dopamine signaling and provide a foundation to examine neural mechanisms of feeding modulation in the fly. PMID:22405204

  16. Streptococcus mutans in a wild, sucrose-eating rat population.

    PubMed

    Coykendall, A L; Specht, P A; Samol, H H

    1974-07-01

    Streptococcus mutans, an organism implicated in dental caries and not previously found outside of man and certain laboratory animals, was isolated from the mouths of wild rats which ate sugar cane. The strains isolated fermented mannitol and sorbitol, and failed to grow in 6.5% NaCl or at 45 C. They formed in vitro plaques on nichrome wires when grown in sucrose broth. They also stored intracellular polysaccharide which could be catabolized by washed, resting cells. Deoxyribonucleic acid-deoxyribonucleic acid reassociations revealed two genetic types. One type shared extensive deoxyribonucleic acid base sequences with S. mutans strains HS6 and OMZ61, two members of a genetic type found in man and laboratory hamsters. The other type seemed unrelated to any S. mutans genetic type previously encountered. It is concluded that the ecological triad of tooth-sucrose-S. mutans is not a phenomenon unique to man and experimental animals. PMID:4601769

  17. Taste pathways that mediate accumbens dopamine release by sapid sucrose.

    PubMed

    Hajnal, Andras; Norgren, Ralph

    2005-03-16

    Although it has been associated with the release of dopamine in the forebrain, reward remains a conundrum in neuroscience. Sucrose is inherently rewarding and its sensory message reaches the brain via the gustatory system. In rodents, the central gustatory system bifurcates in the pontine parabrachial nuclei, one arm forming a standard thalamocortical axis, the other distributing widely in the limbic forebrain. We report here that lesions of the gustatory thalamus fail to affect dopamine overflow during sucrose licking (149+/-5% vs. 149+/-4% for controls). Similar damage to the parabrachial nuclei, which severs the limbic taste projection, substantially reduces dopamine release from the nucleus accumbens (121+/-4% vs. 168+/-9% for sham operated controls; p<0.02). This represents the first demonstration that the affective character of a sensory stimulus might separate from the thalamocortical system as early as the second central synapse. PMID:15763573

  18. Dopaminergic modulation of sucrose acceptance behavior in Drosophila.

    PubMed

    Marella, Sunanda; Mann, Kevin; Scott, Kristin

    2012-03-01

    For an animal to survive in a constantly changing environment, its behavior must be shaped by the complex milieu of sensory stimuli it detects, its previous experience, and its internal state. Although taste behaviors in the fly are relatively simple, with sugars eliciting acceptance behavior and bitter compounds avoidance, these behaviors are also plastic and are modified by intrinsic and extrinsic cues, such as hunger and sensory stimuli. Here, we show that dopamine modulates a simple taste behavior, proboscis extension to sucrose. Conditional silencing of dopaminergic neurons reduces proboscis extension probability, and increased activation of dopaminergic neurons increases extension to sucrose, but not to bitter compounds or water. One dopaminergic neuron with extensive branching in the primary taste relay, the subesophageal ganglion, triggers proboscis extension, and its activity is altered by satiety state. These studies demonstrate the marked specificity of dopamine signaling and provide a foundation to examine neural mechanisms of feeding modulation in the fly.

  19. Alkaline and alkaline earth metal phosphate halides and phosphors

    SciTech Connect

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  20. Electrons trapped in single crystals of sucrose: Induced spin densities

    SciTech Connect

    Box, H.C.; Budzinski, E.E.; Freund, H.G. )

    1990-07-01

    Electrons are trapped at intermolecular sites in single crystals of sucrose {ital X} irradiated at 4.2 K. The coupling tensors for the hyperfine couplings between the electron and surrounding protons have been deduced from electron-nuclear double resonance (ENDOR) data. Electron spin densities at nearby hydroxy protons are positive, whereas spin densities at the more remote protons of carbon-bound hydrogen atoms are negative. The origin of these negative spin densities is discussed.

  1. Electrons trapped in single crystals of sucrose: Induced spin densities

    NASA Astrophysics Data System (ADS)

    Box, Harold C.; Budzinski, Edwin E.; Freund, Harold G.

    1990-07-01

    Electrons are trapped at intermolecular sites in single crystals of sucrose X irradiated at 4.2 K. The coupling tensors for the hyperfine couplings between the electron and surrounding protons have been deduced from electron-nuclear double resonance (ENDOR) data. Electron spin densities at nearby hydroxy protons are positive, whereas spin densities at the more remote protons of carbon-bound hydrogen atoms are negative. The origin of these negative spin densities is discussed.

  2. Sucrose synthase: A unique glycosyltransferase for biocatalytic glycosylation process development.

    PubMed

    Schmölzer, Katharina; Gutmann, Alexander; Diricks, Margo; Desmet, Tom; Nidetzky, Bernd

    2016-01-01

    Sucrose synthase (SuSy, EC 2.4.1.13) is a glycosyltransferase (GT) long known from plants and more recently discovered in bacteria. The enzyme catalyzes the reversible transfer of a glucosyl moiety between fructose and a nucleoside diphosphate (NDP) (sucrose+NDP↔NDP-glucose+fructose). The equilibrium for sucrose conversion is pH dependent, and pH values between 5.5 and 7.5 promote NDP-glucose formation. The conversion of a bulk chemical to high-priced NDP-glucose in a one-step reaction provides the key aspect for industrial interest. NDP-sugars are important as such and as key intermediates for glycosylation reactions by highly selective Leloir GTs. SuSy has gained renewed interest as industrially attractive biocatalyst, due to substantial scientific progresses achieved in the last few years. These include biochemical characterization of bacterial SuSys, overproduction of recombinant SuSys, structural information useful for design of tailor-made catalysts, and development of one-pot SuSy-GT cascade reactions for production of several relevant glycosides. These advances could pave the way for the application of Leloir GTs to be used in cost-effective processes. This review provides a framework for application requirements, focusing on catalytic properties, heterologous enzyme production and reaction engineering. The potential of SuSy biocatalysis will be presented based on various biotechnological applications: NDP-sugar synthesis; sucrose analog synthesis; glycoside synthesis by SuSy-GT cascade reactions. PMID:26657050

  3. New phenylpropanoid esters of sucrose from Polygonum lapathifolium.

    PubMed

    Takasaki, M; Kuroki, S; Kozuka, M; Konoshima, T

    2001-10-01

    Four new phenylpropanoid esters of sucrose, lapathosides A (1), B (2), C (3), and D (4), were isolated from the aerial parts of Polygonum lapathifolium together with known esters, vanicoside B (5) and hydropiperoside (6). The structures of 1-4 were determined by spectral (1D and 2D NMR and MS) analysis. Lapathoside A (1) and vanicoside B (2) showed significant inhibitory effects on the Epstein-Barr virus early antigen activation by tumor-promoters.

  4. Biofilm formation by Escherichia coli in hypertonic sucrose media.

    PubMed

    Kawarai, Taketo; Furukawa, Soichi; Narisawa, Naoki; Hagiwara, Chisato; Ogihara, Hirokazu; Yamasaki, Makari

    2009-06-01

    High osmotic environments produced by NaCl or sucrose have been used as reliable and traditional methods of food preservation. We tested, Escherichia coli as an indicator of food-contaminating bacterium, to determine if it can form biofilm in a hyperosmotic environment. E. coli K-12 IAM1264 did not form biofilm in LB broth that contained 1 M NaCl. However, the bacterium formed biofilm in LB broth that contained 1 M sucrose, although the planktonic growth was greatly suppressed. The biofilm, formed on solid surfaces, such as titer-plate well walls and glass slides, solely around the air-liquid interface. Both biofilm forming cells and planktonic cells in the hypertonic medium adopted a characteristic, fat and filamentous morphology with no FtsZ rings, which are a prerequisite for septum formation. Biofilm forming cells were found to be alive based on propidium iodide staining. The presence of 1 M sucrose in the food environment is not sufficient to prevent biofilm formation by E. coli. PMID:19447340

  5. Increasing sucrose concentrations promote phenylpropanoid biosynthesis in grapevine cell cultures.

    PubMed

    Ferri, Maura; Righetti, Laura; Tassoni, Annalisa

    2011-02-15

    Vitis vinifera cell suspensions are a suitable model system to study the metabolic regulation of a large range of high valuable polyphenols that are important in understanding the physiology of the plant and for nutraceutical, pharmaceutical and medical purposes. Increasing sucrose concentrations were found to promote cell growth and phenylpropanoid biosynthesis in grape cell cultures obtained from cv. Barbera immature berries. This led to an intracellular accumulation and/or release into the media of specific polyphenol families (in particular, anthocyanins, catechins and stilbenes). This effect was partially correlated with a sucrose modulation of the transcription of some key biosynthetic enzymes, such as phenylalanine ammonia lyase, chalcone synthase, chalcone-flavanone isomerase and stilbene synthase. Total catechin amounts, both endogenous and released in the media, were increased in proportion to the sugar concentration, as were anthocyanin and stilbene production. Sugar treatment notably improved the endogenous accumulation and release in the culture media of resveratroloside, a resveratrol mono-glycoside, which is the most abundant stilbene found in grape cultures, especially in cv. Barbera. We hypothesize that high sucrose concentrations (exceeding those naturally-occurring in ripe berries) could play a role in plant defense via the induction of secondary metabolites, such as stilbenes.

  6. Sucrose-replacement by rebaudioside a in a model beverage.

    PubMed

    Majchrzak, Dorota; Ipsen, Annika; Koenig, Juergen

    2015-09-01

    Rebaudioside A (RA), a component of Stevia rebaudiana, is a non-caloric sweetener of natural origin, suitable to meet consumers' demand for sweet taste, but undesirable flavors were reported at high concentrations. Aim of this study was to create a model beverage (ice-tea) in which sucrose was replaced increasingly by RA to identify optimal sensory profile for consumer acceptance. Samples with 20 % and 40 % sucrose replacement by RA, respectively, showed very similar sensory profiles but were significantly higher in some flavor attributes, such as artificial sweetness, licorice-like and metallic, as well as in sweet and bitter aftertaste (p < 0.05) compared to the reference ice-tea. In both hedonic tests, preference and acceptance samples with RA have been judged as comparable to the reference despite perception of some undesirable notes. In view of the results of our study it can be stated that a replacement of 20 % or 40 % sucrose by RA in an ice-tea is achievable. PMID:26345024

  7. Orosensory self-stimulation by sucrose involves brain dopaminergic mechanisms.

    PubMed

    Schneider, L H

    1989-01-01

    The most convincing body of evidence supporting a role for brain dopaminergic mechanisms in sweet taste reward has been obtained using the sham-feeding rat. In rats prepared with a chronic gastric fistula and tested with the cannula open, intake is a direct function of the palatability of the solution offered as well as of the state of food deprivation. Because essentially none of the ingested fluid passes on to the intestine, negative postingestive feedback is eliminated. Thus, the relative orosensory/hedonic potency of the food determines and sustains the rate of sham intake; long periods of food deprivation are not required. In this way, the sham feeding of sweet solutions may be considered a form of oral self-stimulation behavior and afford a preparation through which the neurochemical and neuranatomical substrates of sweet taste reward may be identified. The results obtained in the series of experiments summarized in this paper clearly indicate that central D-1 and D-2 receptor mechanisms are critical for the orosensory self-stimulation by sucrose in the rat. In conclusion, I suggest that such investigations of the roles of brain dopaminergic mechanisms in the sucrose sham-feeding rat preparation may further our understanding of normal and aberrant attractions to sweet fluids in humans (see Cabanac, Drewnowski, and Halmi, this volume), as an innate, positive affective response of human neonates to sucrose and the sustained positive hedonic ratings for glucose when tasted but not when consumed have demonstrated. PMID:2699194

  8. Effect of dietary copper and sucrose on catecholamine concentrations in the adrenal medulla

    SciTech Connect

    Koo, S.I.; Peterson, D.F.; Mason, P.A. KCOM, Kirksville, MO Air Force/SAM/RZP, Brooks AFB, TX )

    1991-03-11

    The severity of copper (Cu) deficiency in the rat is enhanced by dietary sucrose. Possible interactive effects of Cu status and sucrose on catecholamine concentrations in the adrenal medulla were investigated in Cu deficient rats fed a diet were investigated in Cu deficient rats fed a diet containing either glucose or sucrose, as compared with respective Cu-adequate controls. Catecholamines were analyzed by an HPLC method using 3,4-dihydroxybenxylamine as the internal standard. Cu deficiency caused pronounced decreases in norepinephrine and epinephrine, with no significant effect on dopamine, as expressed in nmoles/mg tissue. Dietary sucrose showed no appreciable effect on catecholamines in the adrenal medulla. The adrenal glands were markedly enlarged in Cu-deficient rats, whether fed glucose or sucrose. Adrenal weights were not affected by dietary sucrose. Data indicate that the increased severity of copper deficiency due to sucrose feeding is not associated with changes in adrenal catecholamine output.

  9. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  10. Episodic sucrose intake during food restriction increases synaptic abundance of AMPA receptors in nucleus accumbens and augments intake of sucrose following restoration of ad libitum feeding.

    PubMed

    Peng, X-X; Lister, A; Rabinowitsch, A; Kolaric, R; Cabeza de Vaca, S; Ziff, E B; Carr, K D

    2015-06-01

    Weight-loss dieting often leads to loss of control, rebound weight gain, and is a risk factor for binge pathology. Based on findings that food restriction (FR) upregulates sucrose-induced trafficking of glutamatergic AMPA receptors to the nucleus accumbens (NAc) postsynaptic density (PSD), this study was an initial test of the hypothesis that episodic "breakthrough" intake of forbidden food during dieting interacts with upregulated mechanisms of synaptic plasticity to increase reward-driven feeding. Ad libitum (AL) fed and FR subjects consumed a limited amount of 10% sucrose, or had access to water, every other day for 10 occasions. Beginning three weeks after return of FR rats to AL feeding, when 24-h chow intake and rate of body weight gain had normalized, subjects with a history of sucrose intake during FR consumed more sucrose during a four week intermittent access protocol than the two AL groups and the group that had access to water during FR. In an experiment that substituted noncontingent administration of d-amphetamine for sucrose, FR subjects displayed an enhanced locomotor response during active FR but a blunted response, relative to AL subjects, during recovery from FR. This result suggests that the enduring increase in sucrose consumption is unlikely to be explained by residual enhancing effects of FR on dopamine signaling. In a biochemical experiment which paralleled the sucrose behavioral experiment, rats with a history of sucrose intake during FR displayed increased abundance of pSer845-GluA1, GluA2, and GluA3 in the NAc PSD relative to rats with a history of FR without sucrose access and rats that had been AL throughout, whether they had a history of episodic sucrose intake or not. A history of FR, with or without a history of sucrose intake, was associated with increased abundance of GluA1. A terminal 15-min bout of sucrose intake produced a further increase in pSer845-GluA1 and GluA2 in subjects with a history of sucrose intake during FR

  11. Episodic sucrose intake during food restriction increases synaptic abundance of AMPA receptors in nucleus accumbens and augments intake of sucrose following restoration of ad libitum feeding.

    PubMed

    Peng, X-X; Lister, A; Rabinowitsch, A; Kolaric, R; Cabeza de Vaca, S; Ziff, E B; Carr, K D

    2015-06-01

    Weight-loss dieting often leads to loss of control, rebound weight gain, and is a risk factor for binge pathology. Based on findings that food restriction (FR) upregulates sucrose-induced trafficking of glutamatergic AMPA receptors to the nucleus accumbens (NAc) postsynaptic density (PSD), this study was an initial test of the hypothesis that episodic "breakthrough" intake of forbidden food during dieting interacts with upregulated mechanisms of synaptic plasticity to increase reward-driven feeding. Ad libitum (AL) fed and FR subjects consumed a limited amount of 10% sucrose, or had access to water, every other day for 10 occasions. Beginning three weeks after return of FR rats to AL feeding, when 24-h chow intake and rate of body weight gain had normalized, subjects with a history of sucrose intake during FR consumed more sucrose during a four week intermittent access protocol than the two AL groups and the group that had access to water during FR. In an experiment that substituted noncontingent administration of d-amphetamine for sucrose, FR subjects displayed an enhanced locomotor response during active FR but a blunted response, relative to AL subjects, during recovery from FR. This result suggests that the enduring increase in sucrose consumption is unlikely to be explained by residual enhancing effects of FR on dopamine signaling. In a biochemical experiment which paralleled the sucrose behavioral experiment, rats with a history of sucrose intake during FR displayed increased abundance of pSer845-GluA1, GluA2, and GluA3 in the NAc PSD relative to rats with a history of FR without sucrose access and rats that had been AL throughout, whether they had a history of episodic sucrose intake or not. A history of FR, with or without a history of sucrose intake, was associated with increased abundance of GluA1. A terminal 15-min bout of sucrose intake produced a further increase in pSer845-GluA1 and GluA2 in subjects with a history of sucrose intake during FR

  12. Intermittent access to a sucrose solution for rats causes long-term increases in consumption.

    PubMed

    Eikelboom, Roelof; Hewitt, Randelle

    2016-10-15

    Intermittent access to palatable food can elevate consumption beyond an animal's immediate needs. If adult male rats (with ad lib access to food and water) are provided with a 4% sucrose solution, daily sucrose consumption is determined by the sucrose access schedule: access that is intermittent leads to high levels of consumption. In Experiment 1, sucrose solutions were first provided continuously or every second, third, or fourth day for 23.5h over 49days. Continuous-access sucrose consumption averaged 102g per day, while that for access every fourth day averaged 294g. Daily consumption averages for access every second and third day fell between these two extremes. When all rats were then given alternate-day access to sucrose for 24days in Phase II, the previously established consumption differences were maintained. Body weight was unaffected by sucrose access; rats adjusted their food consumption so that total calorie intake remained constant. In Experiment 2, compared to continuous 4% sucrose solution access, access every third day markedly elevated daily sucrose consumption after only four sucrose exposures. With this shorter Phase I, sucrose intake in the continuous group increased markedly when in Phase II all rats were given alternate day access. In Experiment 3, a lick-by-lick analysis of the difference in sucrose consumption between access every third day and continuous access revealed that all rats were consuming a similar number of sucrose meals; however, the meals were larger both in the first hour and over the whole 24h with intermittent access. This suggests a change in satiety as a mechanism underlying sucrose consumption difference. PMID:27394659

  13. Protein phosphatase activity and sucrose-mediated induction of fructan synthesis in wheat.

    PubMed

    Martínez-Noël, Giselle M A; Tognetti, Jorge A; Salerno, Graciela L; Wiemken, Andres; Pontis, Horacio G

    2009-10-01

    In this work, we analyze protein phosphatase (PP) involvement in the sucrose-mediated induction of fructan metabolism in wheat (Triticum aestivum). The addition of okadaic acid (OA), a PP-inhibitor, to sucrose-fed leaves reduced fructosylsucrose-synthesizing activity (FSS) induction in a dose-dependent manner. The expression of the two enzymes that contribute to FSS activity, 1-SST (1-sucrose:sucrose fructosyltransferase, E.C. 2.4.1.99) and 6-SFT (6-sucrose:fructan fructosyltransferase, E.C. 2.4.1.10), was blocked by 1 microM OA. These results suggest the involvement of a PP type 2A in sucrose signaling leading to fructan synthesis. OA addition to the feeding medium impaired both sucrose accumulation in leaves and the expression of sucrose-H+ symporter (SUT1). It is known that sucrose concentration must exceed a threshold for the induction of fructan metabolism; hence PP2A inhibition may result in lower sucrose levels than required for this induction. OA also induced the vacuolar acid invertase (acid INV) transcript levels suggesting that PP activity might play a role in carbon partitioning. Total extractable PP2A activity decreased during 24 h of treatment with sucrose, in parallel with declining sugar uptake into leaf tissues. In conclusion, our results suggest that PP2A is involved in sucrose-induction of fructan metabolism and may play a role in regulating sucrose uptake, but do not rule out that further steps in sucrose signaling pathway may be affected.

  14. Nitrosative stress and apoptosis in non-anemic healthy rats induced by intravenous iron sucrose similars versus iron sucrose originator.

    PubMed

    Toblli, Jorge E; Cao, Gabriel; Angerosa, Margarita

    2015-04-01

    Iron can both induce and inhibit nitrosative stress. Intracellular iron levels play an important role in nitric oxide (NO(•)) signaling mechanisms. Depending on various factors, such as the cell's redox state and transition metal levels, NO(•) generation may lead to lipid peroxidation and DNA damage as well as both anti- and pro-apoptotic effects. Administration of intravenous iron sucrose originator (IS(ORIG)) has been shown not to cause significant tyrosine nitration or significantly increased caspase 3 levels in non-anemic rats. In this study, the potential of several marketed iron sucrose similars (ISSs) to induce tyrosine nitration and caspase 3 expression in non-anemic rats was assessed. Although the physico-chemical properties of most of the analyzed ISSs complied with the United States Pharmacopeia for iron sucrose injection, all ISSs resulted in higher levels of tyrosine nitration and increased the expression of caspase 3 versus IS(ORIG). Moreover, significant differences were detected in tissue iron distribution between IS(ORIG)- and ISS-treated animals. In general, ISORIG resulted in higher levels of ferritin deposits versus ISSs whereas ISSs showed higher Prussian blue-stainable iron(III) deposits than IS(ORIG). This result suggests that some iron from ISSs bypassed the tightly regulated pathway through resident macrophages of the liver, spleen and bone marrow thus, ending up in the cellular compartment that favors oxidative and or nitrosative stress as well as apoptosis. The results also confirm that polynuclear iron(III)-oxyhydroxide carbohydrates, such as iron sucrose, cannot be fully characterized by physico-chemical methods alone.

  15. A sucrose transporter-interacting protein disulphide isomerase affects redox homeostasis and links sucrose partitioning with abiotic stress tolerance.

    PubMed

    Eggert, Erik; Obata, Toshihiro; Gerstenberger, Anne; Gier, Konstanze; Brandt, Tobias; Fernie, Alisdair R; Schulze, Waltraud; Kühn, Christina

    2016-06-01

    Sucrose accumulation in leaves in response to various abiotic stresses suggests a specific role of this disaccharide for stress tolerance and adaptation. The high-affinity transporter StSUT1 undergoes substrate-induced endocytosis presenting the question as to whether altered sucrose accumulation in leaves in response to stresses is also related to enhanced endocytosis or altered activity of the sucrose transporter. StSUT1 is known to interact with several stress-inducible proteins; here we investigated whether one of the interacting candidates, StPDI1, affects its subcellular localization in response to stress: StPDI1 expression is induced by ER-stress and salt. Both proteins, StSUT1 and StPDI1, were found in the detergent resistant membrane (DRM) fraction, and this might affect internalization. Knockdown of StPDI1 expression severely affects abiotic stress tolerance of transgenic potato plants. Analysis of these plants does not reveal modified subcellular localization or endocytosis of StSUT1, but rather a disturbed redox homeostasis, reduced detoxification of reactive oxygen species and effects on primary metabolism. Parallel observations with other StSUT1-interacting proteins are discussed. The redox status in leaves seems to be linked to the sugar status in response to various stress stimuli and to play a role in stress tolerance. PMID:26670204

  16. Usefulness of organic acid produced by Exiguobacterium sp. 12/1 on neutralization of alkaline wastewater.

    PubMed

    Kulshreshtha, Niha Mohan; Kumar, Anil; Bisht, Gopal; Pasha, Santosh; Kumar, Rita

    2012-01-01

    The aim of this study was to investigate the role of organic acids produced by Exiguobacterium sp. strain 12/1 (DSM 21148) in neutralization of alkaline wastewater emanated from beverage industry. This bacterium is known to be able to grow in medium of pH as high as pH 12.0 and to neutralize alkaline industrial wastewater from pH 12.0 to pH 7.5. The initial investigation on the type of functional groups present in medium, carried out using FT-IR spectroscopy, revealed the presence of peaks corresponding to carbonyl group and hydroxyl group, suggesting the release of carboxylic acid or related metabolic product(s). The identification of specific carboxylic group, carried out using RP-HPLC, revealed the presence of a single peak in the culture supernatant with retention time most similar to formic acid. The concentration of acid produced on different carbon sources was studied as a function of time. Although acid was present in same final concentration, the rate of acid production was highest in case of medium supplemented with sucrose followed by fructose and glucose. The knowledge of metabolic products of the bacterium can be considered as a first step towards realization of its potential for large-scale bioremediation of alkaline wastewater from beverage industry.

  17. Gradient Refractive Index Lenses.

    ERIC Educational Resources Information Center

    Morton, N.

    1984-01-01

    Describes the nature of gradient refractive index (GRIN) lenses, focusing on refraction in these materials, focal length of a thin Wood lens, and on manufacturing of such lenses. Indicates that GRIN lenses of small cross section are in limited production with applications suggested for optical communication and photocopying fields. (JN)

  18. Arterial Stiffness Gradient

    PubMed Central

    Fortier, Catherine; Agharazii, Mohsen

    2016-01-01

    Background Aortic stiffness is a strong predictor of cardiovascular mortality in various clinical conditions. The aim of this review is to focus on the arterial stiffness gradient, to discuss the integrated role of medium-sized muscular conduit arteries in the regulation of pulsatile pressure and organ perfusion and to provide a rationale for integrating their mechanical properties into risk prediction. Summary The physiological arterial stiffness gradient results from a higher degree of vascular stiffness as the distance from the heart increases, creating multiple reflective sites and attenuating the pulsatile nature of the forward pressure wave along the arterial tree down to the microcirculation. The stiffness gradient hypothesis simultaneously explains its physiological beneficial effects from both cardiac and peripheral microcirculatory points of view. The loss or reversal of stiffness gradient leads to the transmission of a highly pulsatile pressure wave into the microcirculation. This suggests that a higher degree of stiffness of medium-sized conduit arteries may play a role in protecting the microcirculation from a highly pulsatile forward pressure wave. Using the ratio of carotid-femoral pulse wave velocity (PWV) to carotid-radial PWV, referred to as PWV ratio, a recent study in a dialysis cohort has shown that the PWV ratio is a better predictor of mortality than the classical carotid-femoral PWV. Key Messages Theoretically, the use of the PWV ratio seems more logical for risk determination than aortic stiffness as it provides a better estimation of the loss of stiffness gradient, which is the unifying hypothesis that explains the impact of aortic stiffness both on the myocardium and on peripheral organs. PMID:27195235

  19. Alkaline pH sensor molecules.

    PubMed

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range.

  20. Evidence for the presence of a sucrose carrier in immature sugar beet tap roots. [Beta vulgaris L

    SciTech Connect

    Lemoine, R.; Daie, J.; Wyse, R. )

    1988-02-01

    The objectives of this work were to determine the path of phloem unloading and if a sucrose carrier was present in young sugar beet (Beta vulgaris L.) taproots. The approach was to exploit the characteristics of the sucrose analog, 1{prime}-fluorosucrose (F-sucrose) which is a poor substrate for acid invertase but is a substrate for sucrose synthase. Ten millimolar each of ({sup 3}H) sucrose and ({sup 14}C)F-sucrose were applied in a 1:1 ratio to an abraded region of an attached leaf for 6 hours. ({sup 14}C)F-sucrose was translocated and accumulated in the roots at a higher rate than ({sup 3}H)sucrose. This was due to ({sup 3}H)sucrose hydrolysis along the translocation path. Presence of ({sup 3}H)hexose and ({sup 14}C)F-sucrose in the root apoplast suggested apoplastic sucrose unloading with its subsequent hydrolysis. Labeled F-sucrose uptake by root tissue discs exhibited biphasic kinetics and was inhibited by unlabeled sucrose, indicating that immature roots have the ability for carrier-mediated sucrose transport from the apoplast. Collectively, in vivo and in vitro data indicate that despite sucrose hydrolysis by the wall-bound invertase, sucrose hydrolysis is not entirely essential for sugar accumulation in this tissue.

  1. Alkaline-resistance model of subtilisin ALP I, a novel alkaline subtilisin.

    PubMed

    Maeda, H; Mizutani, O; Yamagata, Y; Ichishima, E; Nakajima, T

    2001-05-01

    The alkaline-resistance mechanism of the alkaline-stable enzymes is not yet known. To clarify the mechanism of alkaline-resistance of alkaline subtilisin, structural changes of two typical subtilisins, subtilisin ALP I (ALP I) and subtilisin Sendai (Sendai), were studied by means of physicochemical methods. Subtilisin NAT (NAT), which exhibits no alkaline resistance, was examined as a control. ALP I gradually lost its activity, accompanied by protein degradation, but, on the contrary, Sendai was stable under alkaline conditions. CD spectral measurements at neutral and alkaline pH indicated no apparent differences between ALP I and Sendai. A significant difference was observed on measurement of fluorescence emission spectra of the tryptophan residues of ALP I that were exposed on the enzyme surface. The fluorescence intensity of ALP I was greatly reduced under alkaline conditions; moreover, the reduction was reversed when alkaline-treated ALP I was neutralized. The fluorescence spectrum of Sendai remained unchanged. The enzymatic and optical activities of NAT were lost at high pH, indicating a lack of functional and structural stability in an alkaline environment. Judging from these results, the alkaline resistance is closely related to the surface structure of the enzyme molecule.

  2. High sucrose consumption promotes obesity whereas its low consumption induces oxidative stress in Drosophila melanogaster.

    PubMed

    Rovenko, Bohdana M; Kubrak, Olga I; Gospodaryov, Dmytro V; Perkhulyn, Natalia V; Yurkevych, Ihor S; Sanz, Alberto; Lushchak, Oleh V; Lushchak, Volodymyr I

    2015-08-01

    The effects of sucrose in varied concentrations (0.25-20%) with constant amount of yeasts in larval diet on development and metabolic parameters of adult fruit fly Drosophila melanogaster were studied. Larvae consumed more food at low sucrose diet, overeating with yeast. On high sucrose diet, larvae ingested more carbohydrates, despite consuming less food and obtaining less protein derived from yeast. High sucrose diet slowed down pupation and increased pupa mortality, enhanced levels of lipids and glycogen, increased dry body mass, decreased water content, i.e. resulted in obese phenotype. Furthermore, it suppressed reactive oxygen species-induced oxidation of lipids and proteins as well as the activity of superoxide dismutase. The activity of catalase was gender-related. In males, at all sucrose concentrations used catalase activity was higher than at its concentration of 0.25%, whereas in females sucrose concentration virtually did not influence the activity. High sucrose diet increased content of protein thiols and the activity of glucose-6-phosphate dehydrogenase. The increase in sucrose concentration also enhanced uric acid level in females, but caused opposite effects in males. Development on high sucrose diets was accompanied by elevated steady-state insulin-like peptide 3 mRNA level. Finally, carbohydrate starvation at yeast overfeeding on low sucrose diets resulted in oxidative stress reflected by higher levels of oxidized lipids and proteins accompanied by increased superoxide dismutase activity. Potential mechanisms involved in regulation of redox processes by carbohydrates are discussed.

  3. High sucrose consumption promotes obesity whereas its low consumption induces oxidative stress in Drosophila melanogaster.

    PubMed

    Rovenko, Bohdana M; Kubrak, Olga I; Gospodaryov, Dmytro V; Perkhulyn, Natalia V; Yurkevych, Ihor S; Sanz, Alberto; Lushchak, Oleh V; Lushchak, Volodymyr I

    2015-08-01

    The effects of sucrose in varied concentrations (0.25-20%) with constant amount of yeasts in larval diet on development and metabolic parameters of adult fruit fly Drosophila melanogaster were studied. Larvae consumed more food at low sucrose diet, overeating with yeast. On high sucrose diet, larvae ingested more carbohydrates, despite consuming less food and obtaining less protein derived from yeast. High sucrose diet slowed down pupation and increased pupa mortality, enhanced levels of lipids and glycogen, increased dry body mass, decreased water content, i.e. resulted in obese phenotype. Furthermore, it suppressed reactive oxygen species-induced oxidation of lipids and proteins as well as the activity of superoxide dismutase. The activity of catalase was gender-related. In males, at all sucrose concentrations used catalase activity was higher than at its concentration of 0.25%, whereas in females sucrose concentration virtually did not influence the activity. High sucrose diet increased content of protein thiols and the activity of glucose-6-phosphate dehydrogenase. The increase in sucrose concentration also enhanced uric acid level in females, but caused opposite effects in males. Development on high sucrose diets was accompanied by elevated steady-state insulin-like peptide 3 mRNA level. Finally, carbohydrate starvation at yeast overfeeding on low sucrose diets resulted in oxidative stress reflected by higher levels of oxidized lipids and proteins accompanied by increased superoxide dismutase activity. Potential mechanisms involved in regulation of redox processes by carbohydrates are discussed. PMID:26050918

  4. Expression profiling of sucrose metabolizing genes in Saccharum, Sorghum and their hybrids.

    PubMed

    Ramalashmi, K; Prathima, P T; Mohanraj, K; Nair, N V

    2014-10-01

    Sucrose phosphate synthase (SPS; EC 2.4.1.14), sucrose synthase (SuSy; EC 2.4.1.13) and soluble acid invertase (SAI; EC 3.2.1.26) are key enzymes that regulate sucrose fluxes in sink tissues for sucrose accumulation in sugarcane and sorghum. In this study, the expression profiling of sucrose-related genes, i.e. SPS, SuSy and SAI in two sets of hybrids viz., one from a Sorghum × Saccharum cross and the other from a Saccharum × Sorghum cross, high- and low-sucrose varieties, sweet and grain sorghum lines was carried out using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) at monthly intervals. The results indicated differential expression of the three genes in high- and low-sucrose forms. Expression of SPS and SuSy genes was high in high-sucrose varieties, Saccharum × Sorghum hybrids and sweet sorghum and lower in low-sucrose varieties, Sorghum × Saccharum hybrids and grain sorghum. SAI showed a lower expression in high-sucrose varieties, Saccharum × Sorghum hybrids and sweet sorghum and higher expression in low-sucrose varieties, Sorghum × Saccharum hybrids and the grain sorghum. This study describes the positive association of SPS and SuSy and negative association of SAI on sucrose accumulation. This is the first report of differential expression profiling of SPS, SuSy and SAI in intergeneric hybrids involving sugarcane and sorghum, which opens the possibility for production of novel hybrids with improved sucrose content and with early maturity.

  5. Alterations of sucrose preference after Roux-en-Y gastric bypass.

    PubMed

    Bueter, M; Miras, A D; Chichger, H; Fenske, W; Ghatei, M A; Bloom, S R; Unwin, R J; Lutz, T A; Spector, A C; le Roux, C W

    2011-10-24

    Roux-en-Y gastric bypass (gastric bypass) patients reportedly have changes in perception and consumption of sweet-tasting foods. This study aimed to further investigate alterations in sweet food intake in rats and sucrose detection in humans after gastric bypass. Wistar rats were randomized to gastric bypass or sham-operations and preference for sucrose (sweet), sodium chloride (salty), citric acid (sour) and quinine hydrochloride (bitter) was assessed with standard two-bottle intake tests (vs. water). Intestinal T1R2 and T1R3 expression and plasma levels of glucagon-like-peptide 1 (GLP-1) and peptide YY (PYY) were measured. Furthermore, obese patients and normal weight controls were tested for sucrose taste detection thresholds pre- and postoperatively. Visual analogue scales measuring hedonic perception were used to determine the sucrose concentration considered by patients and controls as "just about right" pre- and postoperatively. Gastric bypass reduced the sucrose intake relative to water in rats (p<0.001). Preoperative sucrose exposure reduced this effect. Preference or aversion for compounds representative of other taste qualities in naïve rats remained unaffected. Intestinal T1R2 and T1R3 expression was significantly decreased in the alimentary limb while plasma levels of GLP-1 and PYY were elevated after bypass in rats (p=0.01). Bypass patients showed increased taste sensitivity to low sucrose concentrations compared with controls (p<0.05), but both groups considered the same sucrose concentration as "just about right" postoperatively. In conclusion, gastric bypass reduces sucrose intake relative to water in sucrose-naïve rats, but preoperative sucrose experience attenuates this effect. Changes in sucrose taste detection do not predict hedonic taste ratings of sucrose in bypass patients which remain unchanged. Thus, factors other than the unconditional affective value of the taste may also play a role in determining food preferences after gastric bypass

  6. Stress-gradient plasticity

    PubMed Central

    Chakravarthy, Srinath S.; Curtin, W. A.

    2011-01-01

    A new model, stress-gradient plasticity, is presented that provides unique mechanistic insight into size-dependent phenomena in plasticity. This dislocation-based model predicts strengthening of materials when a gradient in stress acts over dislocation source–obstacle configurations. The model has a physical length scale, the spacing of dislocation obstacles, and is validated by several levels of discrete-dislocation simulations. When incorporated into a continuum viscoplastic model, predictions for bending and torsion in polycrystalline metals show excellent agreement with experiments in the initial strengthening and subsequent hardening as a function of both sample-size dependence and grain size, when the operative obstacle spacing is proportional to the grain size. PMID:21911403

  7. High-Throughput Analysis of Sucrose Fatty Acid Esters by Supercritical Fluid Chromatography/Tandem Mass Spectrometry

    PubMed Central

    Hori, Katsuhito; Tsumura, Kazunobu; Fukusaki, Eiichiro; Bamba, Takeshi

    2014-01-01

    Supercritical fluid chromatography (SFC) coupled with triple quadrupole mass spectrometry was applied to the profiling of sucrose fatty acid esters (SEs). The SFC conditions (column and modifier gradient) were optimized for the effective separation of SEs. In the column test, a silica gel reversed-phase column was selected. Then, the method was used for the detailed characterization of commercial SEs and the successful analysis of SEs containing different fatty acids. The present method allowed for fast and high-resolution separation of monoesters to tetra-esters within a shorter time (15 min) as compared to the conventional high-performance liquid chromatography. The applicability of our method for the analysis of SEs was thus demonstrated. PMID:26819875

  8. The effects of sympathectomy and dexamethasone in rats ingesting sucrose

    PubMed Central

    Franco-Colín, Margarita; Villanueva, Iván; Piñón, Manuel; Racotta, Radu

    2006-01-01

    Both high-sucrose diet and dexamethasone (D) treatment increase plasma insulin and glucose levels and induce insulin resistance. We showed in a previous work (Franco-Colin, et al. Metabolism 2000; 49:1289-1294) that combining both protocols for 7 weeks induced less body weight gain in treated rats without affecting mean daily food intake. Since such an effect may be explained by an increase in caloric expenditure, possibly due to activation of the sympathetic nervous system by sucrose ingestion, in this work, and using 10% sucrose in the drinking water, male Wistar rats were divided into 4 groups. Two groups were sympathectomized using guanethidine (Gu) treatment for 3 weeks. One of these groups of rats received D in the drinking water. Of the 2 groups not receiving Gu, one was the control (C) and the other received D. After 8 weeks a glucose tolerance test was done. The rats were sacrificed and liver triglyceride (TG), perifemoral muscle lipid, and norepinephrine (NE) levels in the liver spleen, pancreas, and heart were determined. Gu-treated rats (Gu and Gu+D groups) showed less than 10% NE concentration compared to C and D rats, less daily caloric intake and body-weight gain, more sucrose intake, and better glucose tolerance. The area under the curve after glucose administration correlated significantly with the mean body weight gain of the rats, except for D group. Groups D (D and Gu+D) also showed less caloric intake and body-weight gain but higher liver weight and TG concentration and lower peripheral muscle mass. The combination of Gu+D treatments showed some peculiar results: negative body weight gain, a fatty liver, and low muscle mass. Though the glucose tolerance test had the worst results for the D group, it showed the best results in the Gu+D group. There were significant interactions for Guan X Dex by two-way ANOVA test for the area under the curve in the glucose tolerance test, muscle mass, and muscle lipids. The results suggest that dexamethasone

  9. Prediction of sweetness intensity for equiratio aspartame/sucrose mixtures.

    PubMed

    Schifferstein, H N

    1995-04-01

    The Equiratio Mixture Model predicts the responses to a series of equiratio mixtures on the basis of the psychophysical functions for the unmixed components. The model predicts the sweetness of mixtures of sugars and sugar-alcohols successfully, but is unable to predict mixture intensity for substances with different dynamic ranges. In this paper, the equi-intensity concept is introduced in the Equiratio Mixture Model by transforming the physical concentrations expressed in molarity into units that produce approximately equi-intense sensations. An empirical test using aspartame/sucrose mixtures shows that the modified Equiratio Mixture Model yields good predictions of mixture intensities.

  10. Effect of sucrose and sweeteners on appetite and energy intake.

    PubMed

    Blundell, J E; Green, S M

    1996-03-01

    The effect of sweetness on appetite control has become important for two reasons. First, the problem of unwanted overconsumption associated with the tendency to gain weight. Second, the desire to lose weight by dieting. Two questions arise: does sweetness (with or without energy) contribute to over-consumption?, and does the replacement of a high energy sweetener (such as sucrose) with an artificial sweetener (such as saccharine or aspartame) lead to weight loss? How do these issues relate to processes involved in weight maintenance?

  11. Effect of sucrose on physical properties of spray-dried whole milk powder.

    PubMed

    Ma, U V Lay; Ziegler, G R; Floros, J D

    2008-11-01

    Spray-dried whole milk powders were prepared from whole condensed milk with various sucrose concentrations (0%, 2.5%, 5%, 7.5%, and 10% w/w), and their glass transition temperature and some physical properties of importance in chocolate manufacture were evaluated. In milk powder samples, the glass transition temperature and free-fat content decreased in a nonlinear manner with sucrose addition. Moreover, increasing sucrose concentration reduced the formation of dents on the particle surface. Addition of sucrose in whole condensed milk increased linearly the apparent particle density and in a nonlinear manner the particle size of spray-dried milk powders. The particle size volume distribution of milk powders with the highest sucrose concentration differed from the log-normal distribution of the other samples due to the formation of large agglomerates. Neither vacuole volume, nor the amorphous state of milk powders was affected by sucrose addition. PMID:19021798

  12. Effect of sucrose on physical properties of spray-dried whole milk powder.

    PubMed

    Ma, U V Lay; Ziegler, G R; Floros, J D

    2008-11-01

    Spray-dried whole milk powders were prepared from whole condensed milk with various sucrose concentrations (0%, 2.5%, 5%, 7.5%, and 10% w/w), and their glass transition temperature and some physical properties of importance in chocolate manufacture were evaluated. In milk powder samples, the glass transition temperature and free-fat content decreased in a nonlinear manner with sucrose addition. Moreover, increasing sucrose concentration reduced the formation of dents on the particle surface. Addition of sucrose in whole condensed milk increased linearly the apparent particle density and in a nonlinear manner the particle size of spray-dried milk powders. The particle size volume distribution of milk powders with the highest sucrose concentration differed from the log-normal distribution of the other samples due to the formation of large agglomerates. Neither vacuole volume, nor the amorphous state of milk powders was affected by sucrose addition.

  13. Effect of sucrose starvation on sycamore (Acer pseudoplatanus) cell carbohydrate and Pi status.

    PubMed

    Rébeillé, F; Bligny, R; Martin, J B; Douce, R

    1985-03-15

    The mobilization of stored carbohydrates during sucrose starvation was studied with sycamore (Acer pseudoplatanus) cells. When sucrose was omitted from the nutrient medium, the intracellular sucrose pool decreased rapidly during the first hours of the experiment, whereas the starch content remained practically unchanged. After 10h of sucrose starvation, starch hydrolysis replaced sucrose breakdown. From this moment, the phosphate-ester pool and respiration rate decreased with time. Conversely, the intracellular Pi concentration increased. 31P n.m.r. of intact sycamore cells indicated that, under these conditions, most of the Pi accumulated in the vacuole. These results strongly suggest that starch breakdown, in contrast with sucrose hydrolysis, is not rapid enough to maintain a high cellular metabolism.

  14. Process for extracting technetium from alkaline solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

    1995-01-01

    A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

  15. Inorganic-organic separators for alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W. (Inventor)

    1978-01-01

    A flexible separator is reported for use between the electrodes of Ni-Cd and Ni-Zn batteries using alkaline electrolytes. The separator was made by coating a porous substrate with a battery separator composition. The coating material included a rubber-based resin copolymer, a plasticizer and inorganic and organic fillers which comprised 55% by volume or less of the coating as finally dried. One or more of the filler materials, whether organic or inorganic, is preferably active with the alkaline electrolyte to produce pores in the separator coating. The plasticizer was an organic material which is hydrolyzed by the alkaline electrolyte to improve conductivity of the separator coating.

  16. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  17. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  18. Transgenic potato tubers accumulate high levels of 1-kestose and nystose: functional identification of a sucrose sucrose 1-fructosyltransferase of artichoke (Cynara scolymus) blossom discs.

    PubMed

    Hellwege, E M; Gritscher, D; Willmitzer, L; Heyer, A G

    1997-11-01

    By screening a cDNA library of artichoke (Cynara scolymus) blossom discs for fructosyltransferases, we isolated a clone designated Cy21. The deduced amino acid sequence shows homology to acid beta-fructosyl hydrolases and to the sucrose-fructan 6-fructosyltransferase (6-SFT) of barley. Transiently expressed in Nicotiana tabacum protoplasts, the Cy21 gene-product synthesized 1-kestose, indicating that Cy21 codes for a sucrose sucrose 1-fructosyltransferase (1-SST). The enzyme worked at physiologically relevant sucrose concentrations (25 mM sucrose). In the protoplast system, 1-kestose seemed to be the only fructan product of the 1-SST. The enzyme activity was not affected by pyridoxal-HCl, an inhibitor of both the beta-fructosyl hydrolase and the fructosyltransferase activity of invertases. The fructosyltransferase activity of the Cy21 gene-product, however, could be inhibited by Zn2+, Ag+ and Cu2+ ions. In artichoke plants the Cy21 transcript was highly abundant in primary roots and blossom discs. Transgenic potato tubers expressing Cy21 contain high levels of 1-kestose along with nystose and traces of fructosyl-nystose, supporting the conclusion that the Cy21 clone encodes a sucrose sucrose 1-fructosyltransferase.

  19. Nickel hydroxide deposited indium tin oxide electrodes as electrocatalysts for direct oxidation of carbohydrates in alkaline medium

    NASA Astrophysics Data System (ADS)

    Ganesh, V.; Farzana, S.; Berchmans, Sheela

    In this work, the direct electrochemical oxidation of carbohydrates using nickel hydroxide modified indium tin oxide (ITO) electrodes in alkaline medium is demonstrated; suggesting the feasibility of using carbohydrates as a novel fuel in alkaline fuel cells applications. The chosen monosaccharides are namely glucose and fructose; disaccharides such as sucrose and lactose; and sugar acid like ascorbic acid for this study. ITO electrodes are chemically modified using a hexagonal lyotropic liquid crystalline phase template electrodeposition of nickel. Structural morphology, growth, orientation and electrochemical behaviour of Ni deposits are characterized using SEM, XRD, XPS and cyclic voltammetry (CV), respectively. Further electrochemical potential cycling process in alkaline medium is employed to convert these Ni deposits into corresponding nickel hydroxide modified electrodes. These electrodes are used as novel platform to perform the electrocatalytic oxidation of various carbohydrates in alkaline medium. It was found that bare and Ni coated ITO electrodes are inactive towards carbohydrates oxidation. The heterogeneous rate constant values are determined and calculated to be two orders of magnitude higher in the case of template method when compared to non-template technique. The observed effect is attributed to the synergistic effect of higher surface area of these deposits and catalytic ability of Ni(II)/Ni(III) redox couple.

  20. Specificity in lipases: A computational study of transesterification of sucrose

    PubMed Central

    Fuentes, Gloria; Ballesteros, Anthonio; Verma, Chandra S.

    2004-01-01

    Computational conformational searches of putative transition states of the reaction of sucrose with vinyl laurate catalyzed by lipases from Candida antarctica B and Thermomyces lanuginosus have been carried out. The dielectric of the media have been varied to understand the role of protein plasticity in modulating the observed regioselective transesterification. The binding pocket of lipase from Candida adapts to the conformational variability of the various substates of the substrates by small, local adjustments within the binding pocket. In contrast, the more constrained pocket of the lipase from Thermomyces adapts by adjusting through concerted global motions between subdomains. This leads to the identification of one large pocket in Candida that accommodates both the sucrose and the lauroyl moieties of the transition state, whereas in Thermomyces the binding pocket is smaller, leading to the localization of the two moieties in two distinct pockets; this partly rationalizes the broader specificity of the former relative to the latter. Mutations have been suggested to exploit the differences towards changing the observed selectivities. PMID:15557256

  1. Biosynthesis of Sucrose and Mannitol as a Function of Leaf Age in Celery (Apium graveolens L.).

    PubMed

    Davis, J M; Fellman, J K; Loescher, W H

    1988-01-01

    In celery (Apium graveolens L.), the two major translocated carbohydrates are sucrose and the acyclic polyol mannitol. Their metabolism, however, is different and their specific functions are uncertain. To compare their roles in carbon partitioning and sink-source transitions, developmental changes in (14)CO(2) labeling, pool sizes, and key enzyme activities in leaf tissues were examined. The proportion of label in mannitol increased dramatically with leaf maturation whereas that in sucrose remained fairly constant. Mannitol content, however, was high in all leaves and sucrose content increased as leaves developed. Activities of mannose-6-P reductase, cytoplasmic and chloroplastic fructose-1,6-bisphosphatases, sucrose phosphate synthase, and sucrose synthase increased with leaf maturation and decreased as leaves senesced. Ribulose bisphosphate carboxylase and nonreversible glyceraldehyde-3-P dehydrogenase activities rose as leaves developed but did not decrease. Thus, sucrose is produced in all photosynthetically active leaves whereas mannitol is synthesized primarily in mature leaves and stored in all leaves. Onset of sucrose export in celery may result from sucrose accumulation in expanding leaves, but mannitol export is clearly unrelated to mannitol concentration. Mannitol export, however, appears to coincide with increased mannitol biosynthesis. Although mannitol and sucrose arise from a common precursor in celery, subsequent metabolism and transport must be regulated separately.

  2. Sucrose in bloom-forming cyanobacteria: loss and gain of genes involved in its biosynthesis.

    PubMed

    Kolman, María A; Salerno, Graciela L

    2016-02-01

    Bloom-forming cyanobacteria are widely distributed in freshwater ecosystems. To cope with salinity fluctuations, cyanobacteria synthesize compatible solutes, such as sucrose, to maintain the intracellular osmotic balance. The screening of cyanobacterial genomes revealed that homologues to sucrose metabolism-related genes only occur in few bloom-forming strains, mostly belonging to Nostocales and Stigonematales orders. Remarkably, among Chroococcales and Oscillatoriales strains, homologues were only found in M. aeruginosa PCC 7806 and Leptolyngbya boryana PCC 6306, suggesting a massive loss of sucrose metabolism in bloom-forming strains of these orders. After a complete functional characterization of sucrose genes in M. aeruginosa PCC 7806, we showed that sucrose metabolism depends on the expression of a gene cluster that defines a transcriptional unit, unique among all sucrose-containing cyanobacteria. It was also demonstrated that the expression of the encoding genes of sucrose-related proteins is stimulated by salt. In view of its ancestral origin in cyanobacteria, the fact that most bloom-forming strains lack sucrose metabolism indicates that the genes involved might have been lost during evolution. However, in a particular strain, like M. aeruginosa PCC 7806, sucrose synthesis genes were probably regained by horizontal gene transfer, which could be hypothesized as a response to salinity fluctuations.

  3. [Succinic acid production from sucrose and sugarcane molasses by metabolically engineered Escherichia coli].

    PubMed

    Li, Feng; Ma, Jiangfeng; Wu, Mingke; Ji, Yaliang; Chen, Wufang; Ren, Xinyi; Jiang, Min

    2015-04-01

    Sugarcane molasses containing large amounts of sucrose is an economical substrate for succinic acid production. However, Escherichia coli AFP111 cannot metabolize sucrose although it is a promising candidate for succinic acid production. To achieve sucrose utilizing ability, we cloned and expressed cscBKA genes encoding sucrose permease, fructokinase and invertase of non-PTS sucrose-utilization system from E. coli W in E. coli AFP111 to generate a recombinant strain AFP111/pMD19T-cscBKA. After 72 h of anaerobic fermentation of the recombinant in serum bottles, 20 g/L sucrose was consumed and 12 g/L succinic acid was produced. During dual-phase fermentation comprised of initial aerobic growth phase followed by anaerobic fermentation phase, the concentration of succinic acid from sucrose and sugarcane molasses was 34 g/L and 30 g/L, respectively, at 30 h of anaerobic phase in a 3 L fermentor. The results show that the introduction of non-PTS sucrose-utilization system has sucrose-metabolizing capability for cell growth and succinic acid production, and can use cheap sugarcane molasses to produce succinic acid.

  4. Exposure to sucrose during periods of withdrawal does not reduce cocaine-seeking behavior in rats

    PubMed Central

    Nicolas, Céline; Lafay-Chebassier, Claire; Solinas, Marcello

    2016-01-01

    Concomitant access to drugs of abuse and alternative rewards such as sucrose has been shown to decrease addiction-related behaviors in animals. Here we investigated whether access to sucrose during abstinence in contexts that are temporally and physically distinct from drug-related contexts could reduce subsequent drug seeking. In addition, we investigated whether a history of cocaine self-administration would alter the rewarding effects of sucrose. Rats self-administered cocaine for ten sessions, while yoked-saline rats received only saline injections, and then we subjected them to a 30-day withdrawal period during which they had access to water and sucrose continuously or intermittently according to a schedule that induces binge-drinking behavior. At the end of the withdrawal period, rats were tested for cocaine seeking behavior during a single 6 h session. We found that exposure to cocaine increased sucrose consumption only when rats had intermittent access to sucrose, but exposure to sucrose did not alter drug seeking regardless of the schedule of access. These results suggest that exposure to cocaine cross-sensitizes to the rewarding effects of sucrose, but exposure to sucrose during abstinence, temporally and physically distinct from drug-related environments, does not to reduce drug seeking. PMID:26997496

  5. Potato sucrose transporter expression in minor veins indicates a role in phloem loading.

    PubMed

    Riesmeier, J W; Hirner, B; Frommer, W B

    1993-11-01

    The major transport form of assimilates in most plants is sucrose. Translocation from the mesophyll into the phloem for long-distance transport is assumed to be carrier mediated in many species. A sucrose transporter cDNA was isolated from potato by complementation of a yeast strain that is unable to grow on sucrose because of the absence of an endogenous sucrose uptake system and the lack of a secreted invertase. The deduced amino acid sequence of the potato sucrose transporter gene StSUT1 is highly hydrophobic and is 68% identical to the spinach sucrose transporter SoSUT1 (pS21). In yeast, the sensitivity of sucrose transport to protonophores and to an increase in pH is consistent with an active proton cotransport mechanism. Substrate specificity and inhibition by protein modifiers are similar to results obtained for sucrose transport into protoplasts and plasma membrane vesicles and for the spinach transporter, with the exception of a reduction in maltose affinity. RNA gel blot analysis shows that the StSUT1 gene is highly expressed in mature leaves, whereas stem and sink tissues, such as developing leaves, show only low expression. RNA in situ hybridization studies show that the transporter gene is expressed specifically in the phloem. Both the properties and the expression pattern are consistent with a function of the sucrose transporter protein in phloem loading.

  6. Differential regulation of two sucrose transporters by defoliation and light conditions in perennial ryegrass.

    PubMed

    Furet, Pierre-Maxime; Berthier, Alexandre; Decau, Marie-Laure; Morvan-Bertrand, Annette; Prud'homme, Marie-Pascale; Noiraud-Romy, Nathalie; Meuriot, Frédéric

    2012-12-01

    Sucrose transport between source and sink tissues is supposed to be a key-step for an efficient regrowth of perennial rye-grass after defoliation and might be altered by light conditions. We assessed the effect of different light regimes (high vs low light applied before or after defoliation) on growth, fructans and sucrose mobilization, as well as on sucrose transporter expression during 14 days of regrowth. Our results reported that defoliation led to a mobilization of C reserves (first sucrose and then fructans), which was parallel to an induction of LpSUT1 sucrose transporter expression in source and sink tissues (i.e. leaf sheaths and elongating leaf bases, respectively) irrespective to light conditions. Light regime (high or low light) had little effects on regrowth and on C reserves mobilization during the first 48 h of regrowth after defoliation. Thereafter, low light conditions, delaying the recovery of photosynthetic capacities, had a negative effect on C reserves re-accumulation (especially sucrose). Surprisingly, high light did not enhance sucrose transporter expression. Indeed, while light conditions had no effect on LpSUT1 expression, LpSUT2 transcripts levels were enhanced for low light grown plants. These results indicate that two sucrose transporter currently identified in Lolium perenne L. are differentially regulated by light and sucrose.

  7. Sucrose functions as a signal involved in the regulation of strawberry fruit development and ripening.

    PubMed

    Jia, Haifeng; Wang, Yuanhua; Sun, Mingzhu; Li, Bingbing; Han, Yu; Zhao, Yanxia; Li, Xingliang; Ding, Ning; Li, Chen; Ji, Wenlong; Jia, Wensuo

    2013-04-01

    Fleshy fruits are classically divided into climacteric and nonclimacteric types. It has long been thought that the ripening of climacteric and nonclimacteric fruits is regulated by ethylene and abscisic acid (ABA), respectively. Here, we report that sucrose functions as a signal in the ripening of strawberry (Fragaria × ananassa), a nonclimacteric fruit. Pharmacological experiments, as well as gain- and loss-of-function studies, were performed to demonstrate the critical role of sucrose in the regulation of fruit ripening. Fruit growth and development were closely correlated with a change in sucrose content. Exogenous sucrose and its nonmetabolizable analog, turanose, induced ABA accumulation in fruit and accelerated dramatically fruit ripening. A set of sucrose transporters, FaSUT1-7, was identified and characterized, among which FaSUT1 was found to be a major component responsible for sucrose accumulation during fruit development. RNA interference-induced silencing of FaSUT1 led to a decrease in both sucrose and ABA content, and arrested fruit ripening. By contrast, overexpression of FaSUT1 led to an increase in both sucrose and ABA content, and accelerated fruit ripening. In conclusion, this study demonstrates that sucrose is an important signal in the regulation of strawberry fruit ripening.

  8. Sucrose produces withdrawal and dopamine-sensitive reinforcing effects in planarians.

    PubMed

    Zhang, Charlie; Tallarida, Christopher S; Raffa, Robert B; Rawls, Scott M

    2013-03-15

    Sucrose produces physical dependence and reinforcing effects in rats. We hypothesized that similar effects could be demonstrated in planarians, the earliest animal with a centralized nervous system. We used two assays, one that quantifies withdrawal responses during drug absence as a reduction in motility and another that quantifies reinforcing effects using a conditioned place preference (CPP) design. In withdrawal experiments, planarians exposed to sucrose (1%) for 60 min and then tested in water for 5 min displayed reduced motility compared to water controls. Acute or continuous sucrose (1%) exposure did not affect motility. CPP experiments used a biased design to capitalize upon planarians' natural preference for the dark (pretest, sucrose conditioning in the light, posttest). Planarians conditioned with sucrose (1%) displayed a greater preference shift than sucrose-naïve planarians. Glucose (0.1, 1%), but not the non-digestible disaccharide lactulose (0.1, 1%), also produced a greater preference shift than water-exposed planarians. Development of sucrose-induced CPP was inhibited when sucrose (1%) conditioning was conducted in combination with dopamine receptor antagonists SCH 23390 (1 μM) or sulpiride (1 μM). These results suggest that the rewarding and reinforcing effects of sugar are highly conserved across species and that planarians offer an invertebrate model to provide insight into the pharmacological effects of sucrose and related sweeteners.

  9. Photocatalytic properties of hierarchical ZnO flowers synthesized by a sucrose-assisted hydrothermal method

    NASA Astrophysics Data System (ADS)

    Lv, Wei; Wei, Bo; Xu, Lingling; Zhao, Yan; Gao, Hong; Liu, Jia

    2012-10-01

    In this work, hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. The thermogravimetric analysis/differential thermal analysis (TGA-DTA) and Fourier transform infrared spectra (FTIR) showed that sucrose acted as a complexing agent in the synthesis process and assisted combustion during annealing. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. The sucrose added ZnO flowers showed improved activity, which was mainly attributed to the better crystallinity as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The effect of sucrose amount on photocatalytic activity was also studied.

  10. Biosynthesis of sucrose and mannitol as a function of leaf age in celery (Apium graveolens L. )

    SciTech Connect

    Davis, J.M.; Fellman, J.K.; Loescher, W.H.

    1988-01-01

    In celery (Apium graveolens L.), the two major translocated carbohydrates are sucrose and the acyclic polyol mannitol. Their metabolism, however, is different and their specific functions are uncertain. To compare their roles in carbon partitioning and sink-source transitions, developmental changes in /sup 14/CO/sub 2/ labeling, pool sizes, and key enzyme activities in leaf tissues were examined. The proportion of label in mannitol increased dramatically with leaf maturation whereas that in sucrose remained fairly constant. Mannitol content, however, was high in all leaves and sucrose content increased as leaves developed. Activities of mannose-6-P reductase, cytoplasmic and chloroplastic fructose-1,6-bis-phosphatases, sucrose phosphate synthase, and sucrose synthase increased with leaf maturation and decreased as leaves senesced. Ribulose bisphosphate carboxylase and nonreversible glyceraldehyde-3-P dehydrogenase activities rose as leaves developed but did not decrease. Thus, sucrose is produced in all photosynthetically active leaves whereas mannitol is synthesized primarily in mature leaves and stored in all leaves. Onset of sucrose export in celery may result from sucrose accumulation in expanding leaves, but mannitol export is clearly unrelated to mannitol concentration. Mannitol export, however, appears to coincide with increased mannitol biosynthesis. Although mannitol and sucrose arise from a common precursor in celery, subsequent metabolism and transport must be regulated separately.

  11. Sensory evaluation of mixtures of maltitol or aspartame, sucrose and an orange aroma.

    PubMed

    Nahon, D F; Roozen, J P; de Graaf, C

    1998-02-01

    The suitability of Beidler's mixture equation for mixtures of sucrose and maltitol as well as for mixtures of sucrose and aspartame was examined in the presence of an orange aroma. The mean scores for the attribute sweet remained constant for each combination of sucrose and maltitol and for each combination of sucrose and aspartame. Therefore, Beidler's mixture equation can be used to choose combinations of sucrose and maltitol and of sucrose and aspartame giving the same sweetness. Quantitative descriptive analysis of different solutions indicated that the flavour profiles of sucrose and maltitol did not differ significantly at a constant concentration of orange aroma. However, flavour profiles of solutions with increasing aspartame concentrations (but constant aroma levels) showed significantly higher scores for the attributes sour, chemical and aftertaste. Addition of orange aroma provided the different solutions with a more distinct flavour. The mean scores for the attributes orange, sour, fruity and aftertaste increased significantly for most of the sucrose-maltitol mixtures. This effect of orange aroma was even more pronounced in solutions containing combinations of sucrose and aspartame. Further comments on the attribute aftertaste showed similar terms for the different solutions, the most often mentioned being orange, sour, fruity and chemical for solutions containing the orange aroma. The aftertaste of solutions containing relatively more aspartame was mainly described as sweet and chemical.

  12. Biochemical and physiological properties of alkaline phosphatases in five isolates of marine bacteria.

    PubMed Central

    Hassan, H M; Pratt, D

    1977-01-01

    The alkaline phosphatase activities of five unique isolates of marine bacteria were found to be associated with the periplasmic space; however, the enzymes from these isolates differed with respect to their repressibility, the apparent number of isoenzymes, the necessity for Mg2 for activity, and the conditions required for their release. With three of the isolates, the enzyme was released when cells that had been washed in 0.5 M NaCl were suspended in sucrose; however, with the other two isolates, one required the additional presence of tris(hydroxymethyl)aminomethane and the other required the presence of lysozyme and ethylenediaminetetraacetic acid. In two isolates the activity was constitutive, in two it was partially repressed, and in one it was completely repressed by inorganic phosphate. The repression of activity was associated with corresponding changes of activity bands as seen by acrylamide gel electrophoresis. Images PMID:845125

  13. Composite seal reduces alkaline battery leakage

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Plitt, K. F.

    1965-01-01

    Composite seal consisting of rubber or plastic washers and a metal washer reduces alkaline battery leakage. Adhesive is applied to each washer interface, and the washers are held together mechanically.

  14. Ratiometric electrochemical detection of alkaline phosphatase.

    PubMed

    Goggins, Sean; Naz, Christophe; Marsh, Barrie J; Frost, Christopher G

    2015-01-11

    A novel ferrocene-derived substrate for the ratiometric electrochemical detection of alkaline phosphatase (ALP) was designed and synthesised. It was demonstrated to be an excellent electrochemical substrate for the ALP-labelled enzyme-linked immunosorbent assay (ELISA).

  15. Evaluation of the alkaline electrolysis of zinc

    SciTech Connect

    Meisenhelder, J.H.; Brown, A.P.; Loutfy, R.O.; Yao, N.P.

    1981-05-01

    The alkaline leach and electrolysis process for zinc production is compared to the conventional acid-sulfate process in terms of both energy saving and technical merit. In addition, the potential for industrial application of the alkaline process is discussed on the basis of present market conditions, possible future zinc market scenarios, and the probability of increased secondary zinc recovery. In primary zinc production, the energy-saving potential for the alkaline process was estimated to be greater than 10%, even when significantly larger electrolysis current densities than those required for the sulfate process are used. The principal technical advantages of the alkaline process are that it can handle low-grade, high-iron-content or oxidized ores (like most of those found in the US) in a more cost- and energy-efficient manner than can the sulfate process. Additionally, in the electrowinning operation, the alkaline process should be technically superior because a dendritic or sponge deposit is formed that is amenable to automated collection without interruption of the electrolysis. Also, use of the higher current densities would result in significant capital cost reductions. Alkaline-based electrolytic recovery processes were considered for the recycling of zinc from smelter baghouse dusts and from the potential source of nickel/zinc electric-vehicle batteries. In all comparisons, an alkaline process was shown to be technically superior and, particularly for the baghouse dusts, energetically and economically superior to alternatively proposed recovery methods based on sulfate electrolysis. It is concluded that the alkaline zinc method is an important alternative technology to the conventional acid zinc process. (WHK)

  16. Toxicity of alkalinity to Hyalella azteca

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.

    1997-01-01

    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  17. Technetium recovery from high alkaline solution

    DOEpatents

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  18. Alkaline tolerant dextranase from streptomyces anulatus

    DOEpatents

    Decker, Stephen R.; Adney, William S.; Vinzant, Todd B.; Himmel, Michael E.

    2003-01-01

    A process for production of an alkaline tolerant dextranase enzyme comprises culturing a dextran-producing microorganism Streptomyces anulatus having accession no. ATCC PTA-3866 to produce an alkaline tolerant dextranase, Dex 1 wherein the protein in said enzyme is characterized by a MW of 63.3 kDa and Dex 2 wherein its protein is characterized by a MW of 81.8 kDa.

  19. Gradient echo MRI

    PubMed Central

    Copenhaver, B R.; Shin, J; Warach, S; Butman, J A.; Saver, J L.; Kidwell, C S.

    2009-01-01

    Background: Recent studies have demonstrated that gradient echo (GRE) MRI sequences are as accurate as CT for the detection of intracerebral hemorrhage (ICH) in the context of acute stroke. However, many physicians who currently read acute stroke imaging studies may be unfamiliar with interpretation of GRE images. Methods: An NIH Web-based training program was developed including a pretest, tutorial, and posttest. Physicians involved in the care of acute stroke patients were encouraged to participate. The tutorial covered acute, chronic, and mimic hemorrhages as they appear on CT, diffusion-weighted imaging, and GRE sequences. Ability of users to identify ICH presence, type, and age on GRE was compared from the pretest to posttest timepoint. Results: A total of 104 users completed the tutorial. Specialties represented included general radiology (42%), general neurology (16%), neuroradiology (15%), stroke neurology (14%), emergency medicine (1%), and other (12%). Median overall score improved pretest to posttest from 66.7% to 83.3%, p < 0.001. Improvement by category was as follows: acute ICH, 66.7%–100%, p < 0.001; chronic ICH, 33.3%–66.7%, p < 0.001; ICH negatives/mimics, 100%–100%, p = 0.787. Sensitivity for identification of acute hemorrhage improved from 68.2% to 96.4%. Conclusions: Physicians involved in acute stroke care achieved significant improvement in gradient echo (GRE) hemorrhage interpretation after completing the NIH GRE MRI tutorial. This indicates that a Web-based tutorial may be a viable option for the widespread education of physicians to achieve an acceptable level of diagnostic accuracy at reading GRE MRI, thus enabling confident acute stroke treatment decisions. GLOSSARY AHA/ASA = American Heart Association/American Stroke Association; CME = continuing medical education; DWI = diffusion-weighted imaging; GRE = gradient echo; ICH = intracerebral hemorrhage; tPA = tissue plasminogen activator. PMID:19414724

  20. Gradient equivalent crystal theory.

    PubMed

    Zypman, F R; Ferrante, J

    2006-07-01

    This paper presents an extension of the formalism of equivalent crystal theory (ECT) by introducing an electron density gradient term so that the total model density becomes a more accurate representation of the real local density. Specifically, we allow for the electron density around a lattice site to have directionality, in addition to an average value, as assumed in ECT. We propose that an atom senses its neighbouring density as a weighted sum-the weights given by the its own electronic probability. As a benchmark, the method is used to compute vacancy migration energy curves of iron. These energies are in good agreement with previously published results. PMID:21690822

  1. Mass spectrometry-based method to investigate the natural selectivity of sucrose as the sugar transport form for plants.

    PubMed

    Yuan, Hang; Wu, Yile; Liu, Wu; Liu, Yan; Gao, Xiang; Lin, Jinming; Zhao, Yufen

    2015-04-30

    Sucrose is the carbon skeletons and energy vector for plants, which is important for plants growth. Among thousands of disaccharides in Nature, why chose sucrose for plants? In this paper, we analyzed the intrinsic structural characteristics of four sucrose isomers with different glycosidic linkage by mass spectrometry (MS) technique. Our results show that sucrose has the most labile glycosidic bond compared with other three isomers, which is helpful for releasing glucose and fructose unit. Besides, sucrose has the most stable integral structure, which is hard to dehydrate and degrade into fragments through losing one or three even four-carbon units, just as its three isomers. In other words, sucrose is more easily holds an integral structure during the transport process, whenever it is necessary, and sucrose can be cleaved into glucose and fructose easily. Besides, we also investigate the internal relationship of sucrose with K(+) by tandem mass spectrometry and viscosity measurement. The related results have shown that the K(+) can stabilize sucrose to a greater extent than the Na(+). Furthermore, under the same conditions, K(+) ions reduce the viscosity of sucrose-water system much more than Na(+). These results suggest that K(+) is a better co-transporter for sucrose. Of course, the transport of sucrose in plants is a very complicated process, which is involved in many proteins. This paper directly accounts for the basic structure feature of sucrose, and the results discovered could provide the novel insight for the answer why Nature chose sucrose for plants.

  2. Alkaline Water and Longevity: A Murine Study

    PubMed Central

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  3. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  4. Sucrose induces expression of the sorbitol-6-phosphate dehydrogenase gene in source leaves of loquat.

    PubMed

    Suzuki, Yasuo; Dandekar, Abhaya M

    2014-03-01

    Rosaceae fruit trees use sorbitol and sucrose as translocating sugars and the sorbitol-to-sucrose ratio in source leaves determines apple fruit quality. Here, we investigate the effects of sugars on the expression of genes encoding key photosynthetic enzymes, including sorbitol-6-phosphate dehydrogenase (S6PDH, EC 1.1.1.200), sucrose phosphate synthase (SPS, EC 2.4.1.14), and ADP-glucose pyrophosphorylase (ADPGPPase, EC 2.7.7.27) to understand the sugar-signaling mechanism in Rosaceae fruit trees. Mature leaf-petiole cuttings of loquat (Eriobotrya japonica Lindl. cv. Mogi) were supplied with a water, sorbitol or sucrose solution for 2 days at 20°C. The relative levels of the transcripts were analyzed by real-time polymerase chain reaction (PCR). S6PDH transcription was decreased by sorbitol but drastically increased by sucrose. SPS and ADPGPPase large subunit transcription were decreased by sucrose and sorbitol. The simultaneous application of sorbitol and sucrose revealed that S6PDH transcription increased in a dose-dependent manner with sucrose. These results show that both sorbitol and sucrose work as signaling molecules in source organs of Rosaceae fruit trees. These trees have mechanisms to positively keep sorbitol as the dominant translocating sugar, suggesting that sorbitol plays an important role in their survival strategy. Effects of various sugars on S6PDH expression were investigated. Palatinose, a sucrose analog, increased S6PDH transcription much more drastically than sucrose. Mannose and 3-O-methylglucose, glucose analogs, also increased S6PDH transcription; however, glucose did not. Models of sugar signaling in source organs of Rosaceae fruit trees are discussed.

  5. The effects of nicotine and sucrose on spatial memory and attention.

    PubMed

    Harte, C B; Kanarek, R B

    2004-04-01

    Both nicotine and sucrose can enhance performance on cognitive tasks. However, little is known about whether nicotine and sucrose could act jointly to augment mental performance. To investigate if there is an interaction between nicotine and sucrose on cognitive behavior, performance on a continuous performance task (CPT) and a spatial memory task was examined in 14 healthy smokers after they had drunk 8 oz of either a sucrose- or aspartame-containing beverage, and then chewed a piece of gum containing either 2 mg nicotine or no nicotine. To assess changes in mood as a function of nicotine and sucrose intake, the profile of mood states (POMS) test was administered three times during each test session. Participants made significantly more correct responses and significantly fewer incorrect responses on the CPT when they received nicotine than when they received the placebo gum. Closer analysis of the data revealed that there was an interaction between sucrose consumption and nicotine intake. Nicotine increased hits and decreased misses when participants were given the sucrose-containing beverage, but not when they were given the aspartame-containing beverage. Neither nicotine nor sucrose affected spatial memory or mood across experimental sessions. However, when data were analyzed for just the first session, participants who drank the sucrose-containing beverage performed significantly better on the spatial memory task than those who drank the aspartame-containing beverage. No gender differences in the effects of nicotine or sucrose on cognitive performance were detected. The results provide support that both nicotine and sucrose have positive effects on cognitive behavior, and that under some conditions the two variables have additive effects on performance.

  6. Energy in density gradient

    SciTech Connect

    Vranjes, J.; Kono, M.

    2015-01-15

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work, the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindrical configuration. This is of practical importance for drift wave instability in various plasmas, and, in particular, in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit volume (per second) in quiet regions in the corona. Consequently, within the life-time of a magnetic structure such energy losses can easily be compensated by the stochastic drift wave heating.

  7. A Constructed Alkaline Consortium and Its Dynamics in Treating Alkaline Black Liquor with Very High Pollution Load

    PubMed Central

    Yang, Chunyu; Cao, Guangchun; Li, Yang; Zhang, Xiaojun; Ren, Hongyan; Wang, Xia; Feng, Jinhui; Zhao, Liping; Xu, Ping

    2008-01-01

    Background Paper pulp wastewater resulting from alkaline extraction of wheat straw, known as black liquor, is very difficult to be treated and causes serious environmental problems due to its high pH value and chemical oxygen demand (COD) pollution load. Lignin, semicellulose and cellulose are the main contributors to the high COD values in black liquor. Very few microorganisms can survive in such harsh environments of the alkaline wheat straw black liquor. A naturally developed microbial community was found accidentally in a black liquor storing pool in a paper pulp mill of China. The community was effective in pH decreasing, color and COD removing from the high alkaline and high COD black liquor. Findings Thirty-eight strains of bacteria were isolated from the black liquor storing pool, and were grouped as eleven operational taxonomy units (OTUs) using random amplified polymorphic DNA-PCR profiles (RAPD). Eleven representative strains of each OTU, which were identified as genera of Halomonas and Bacillus, were used to construct a consortium to treat black liquor with a high pH value of 11.0 and very high COD pollution load of 142,600 mg l−1. After treatment by the constructed consortium, about 35.4% of color and 39,000 mg l−1 (27.3%) CODcr were removed and the pH decreased to 7.8. 16S rRNA gene polymerase chain reaction denaturant gradient gel electrophoresis (PCR-DGGE) and gas chromatography/mass spectrometry (GC/MS) analysis suggested a two-stage treatment mechanism to elucidate the interspecies collaboration: Halomonas isolates were important in the first stage to produce organic acids that contributed to the pH decline, while Bacillus isolates were involved in the degradation of lignin derivatives in the second stage under lower pH conditions. Conclusions/Significance Tolerance to the high alkaline environment and good controllability of the simple consortium suggested that the constructed consortium has good potential for black liquor treatment

  8. Real-time microsensor measurement of local metabolic activities in ex vivo dental biofilms exposed to sucrose and treated with chlorhexidine.

    PubMed

    von Ohle, Christiane; Gieseke, Armin; Nistico, Laura; Decker, Eva Maria; DeBeer, Dirk; Stoodley, Paul

    2010-04-01

    Dental biofilms are characterized by structural and functional heterogeneity. Due to bacterial metabolism, gradients develop and diverse ecological microniches exist. The aims of this study were (i) to determine the metabolic activity of microorganisms in naturally grown dental biofilms ex vivo by measuring dissolved oxygen (DO) and pH profiles with microelectrodes with high spatial resolution and (ii) to analyze the impact of an antimicrobial chlorhexidine (CHX) treatment on microbial physiology during stimulation by sucrose in real time. Biofilms were cultivated on standardized human enamel surfaces in vivo. DO and pH profiles were measured in a flow cell system in sterile human saliva, after sucrose addition (10%), again after alternative treatment of the sucrose exposed biofilms with CHX (0.2%) for 1 or 10 min or after being killed with paraformaldehyde (4%). Biofilm structure was visualized by vitality staining with confocal microscopy. With saliva as the sole nutrient source oxygen consumption was high within the superficial biofilm layers rendering deeper layers (>220 mum) anoxic. Sucrose addition induced the thickness of the anaerobic zone to increase with a concurrent decrease in pH (7.1 to 4.4). CHX exposure reduced metabolic activity and microbial viability at the biofilm surface and drove metabolic activity deeper into the biofilm. CHX treatment led to a reduced viability at the biofilm surface with minor influence on overall biofilm physiology after 1 min; even after 10 min there was measurable respiration and fermentation inside the biofilm. However, the local microenvironment was more aerated, less acidogenic, and presumably less pathogenic.

  9. Identification of sucrose synthase as an actin-binding protein

    NASA Technical Reports Server (NTRS)

    Winter, H.; Huber, J. L.; Huber, S. C.; Davies, E. (Principal Investigator)

    1998-01-01

    Several lines of evidence indicate that sucrose synthase (SuSy) binds both G- and F-actin: (i) presence of SuSy in the Triton X-100-insoluble fraction of microsomal membranes (i.e. crude cytoskeleton fraction); (ii) co-immunoprecipitation of actin with anti-SuSy monoclonal antibodies; (iii) association of SuSy with in situ phalloidin-stabilized F-actin filaments; and (iv) direct binding to F-actin, polymerized in vitro. Aldolase, well known to interact with F-actin, interfered with binding of SuSy, suggesting that a common or overlapping binding site may be involved. We postulate that some of the soluble SuSy in the cytosol may be associated with the actin cytoskeleton in vivo.

  10. Dimerization effect of sucrose octasulfate on rat FGF1

    PubMed Central

    Kulahin, N.; Kiselyov, V.; Kochoyan, A.; Kristensen, O.; Kastrup, Jette S.; Berezin, V.; Bock, E.; Gajhede, M.

    2008-01-01

    Fibroblast growth factors (FGFs) constitute a family of at least 23 structurally related heparin-binding proteins that are involved in regulation of cell growth, survival, differentiation and migration. Sucrose octasulfate (SOS), a chemical analogue of heparin, has been demonstrated to activate FGF signalling pathways. The structure of rat FGF1 crystallized in the presence of SOS has been determined at 2.2 Å resolution. SOS-mediated dimerization of FGF1 was observed, which was further supported by gel-filtration experiments. The major contributors to the sulfate-binding sites in rat FGF1 are Lys113, Lys118, Arg122 and Lys128. An arginine at position 116 is a consensus residue in mammalian FGF molecules; however, it is a serine in rat FGF1. This difference may be important for SOS-mediated FGF1 dimerization in rat. PMID:18540049

  11. A novel zinc finger protein encoded by a couch potato homologue from Solanum tuberosum enables a sucrose transport-deficient yeast strain to grow on sucrose.

    PubMed

    Kühn, C; Frommer, W B

    1995-06-25

    A yeast strain deficient in secreted invertase but expressing a cytoplasmic sucrose synthase has been used to select for potato genes that enable growth on sucrose as the sole carbon source by suppressing the sucrose uptake deficiency. Besides the already known sucrose transporter gene (StSUT1), ten different suppressor clones were identified and characterized. One of these cDNAs (PCP1) enabled efficient growth of the mutant yeast strain and mediated uptake of radiolabeled sucrose. The cDNA encodes a protein of 509 amino acids which is highly hydrophilic and thus does not seem to represent a transporter. Sequence comparisons show that the protein contains zinc finger motifs and shares weak homologies with the Drosophila couch potato gene, which serves as a transcriptional regulator, indicating that PCP1 activates a silent endogenous sucrose uptake system. The other suppressor clones encode either putative transcriptional regulators, protein kinases or enzymes involved in thiamine biosynthesis, ferredoxin reduction or glutamyl tRNA reduction and suppress the phenotype by unknown mechanisms.

  12. Sucrose partitioning between vascular bundles and storage parenchyma in the sugarcane stem: a potential role for the ShSUT1 sucrose transporter.

    PubMed

    Rae, Anne L; Perroux, Jai M; Grof, Christopher P L

    2005-04-01

    A transporter with homology to the SUT/SUC family of plant sucrose transporters was isolated from a sugarcane (Saccharum hybrid) stem cDNA library. The gene, designated ShSUT1, encodes a protein of 517 amino acids, including 12 predicted membrane-spanning domains and a large central cytoplasmic loop. ShSUT1 was demonstrated to be a functional sucrose transporter by expression in yeast. The estimated K(m) for sucrose of the ShSUT1 transporter was 2 mM at pH 5.5. ShSUT1 was expressed predominantly in mature leaves of sugarcane that were exporting sucrose and in stem internodes that were actively accumulating sucrose. Immunolocalization with a ShSUT1-specific antiserum identified the protein in cells at the periphery of the vascular bundles in the stem. These cells became lignified and suberized as stem development proceeded, forming a barrier to apoplasmic solute movement. However, the movement of the tracer dye, carboxyfluorescein from phloem to storage parenchyma cells suggested that symplasmic connections are present. ShSUT1 may have a role in partitioning of sucrose between the vascular tissue and sites of storage in the parenchyma cells of sugarcane stem internodes.

  13. Identification and characterization of the Populus sucrose synthase gene family.

    PubMed

    An, Xinmin; Chen, Zhong; Wang, Jingcheng; Ye, Meixia; Ji, Lexiang; Wang, Jia; Liao, Weihua; Ma, Huandi

    2014-04-10

    In this study, we indentified 15 sucrose synthase (SS) genes in Populus and the results of RT-qPCR revealed that their expression patterns were constitutive and partially overlapping but diverse. The release of the most recent Populus genomic data in Phytozome v9.1 has revealed the largest SS gene family described to date, comprising 15 distinct members. This information will now enable the analysis of transcript expression profiles for those that have not been previously reported. Here, we performed a comprehensive analysis of SS genes in Populus by describing the gene structure, chromosomal location and phylogenetic relationship of each family member. A total of 15 putative SS gene members were identified in the Populus trichocarpa (Torr. & Gray) genome using the SS domain and amino acid sequences from Arabidopsis thaliana as a probe. A phylogenetic analysis indicated that the 15 members could be classified into four groups that fall into three major categories: dicots, monocots & dicots 1 (M & D 1), and monocots & dicots 2 (M & D 2). In addition, the 15 SS genes were found to be unevenly distributed on seven chromosomes. The two conserved domains (sucrose synthase and glycosyl transferase) were found in this family. Meanwhile, the expression profiles of all 15 gene members in seven different organs were investigated in Populus tomentosa (Carr.) by using RT-qPCR. Additional analysis indicated that the poplar SS gene family is also involved in response to water-deficit. The current study provides basic information that will assist in elucidating the functions of poplar SS family. PMID:24508272

  14. Pursuing the Pavlovian Contributions to Induction in Rats Responding for 1% Sucrose Reinforcement

    ERIC Educational Resources Information Center

    Weatherly, Jeffrey N.; Huls, Amber; Kulland, Ashley

    2007-01-01

    The present study investigated whether Pavlovian conditioning contributes, in the form of the response operandum serving as a conditioned stimulus, to the increase in the rate of response for 1% liquid-sucrose reinforcement when food-pellet reinforcement is upcoming. Rats were exposed to conditions in which sign tracking for 1% sucrose was…

  15. Sucrose Increases the Activation Energy Barrier for Actin-Myosin Strong Binding

    PubMed Central

    Jackson, Del R.; Webb, Milad; Stewart, Travis J.; Phillips, Travis; Carter, Michael; Cremo, Christine R.; Baker, Josh E.

    2014-01-01

    To determine the mechanism by which sucrose slows in vitro actin sliding velocities, V, we used stopped flow kinetics and a single molecule binding assay, SiMBA. We observed that in the absence of ATP, sucrose (880 mM) slowed the rate of actin-myosin (A-M) strong binding by 71 ± 8% with a smaller inhibitory effect observed on spontaneous rigor dissociation (21 ± 3%). Similarly, in the presence of ATP, sucrose slowed strong binding associated with Pi release by 85 ± 9% with a smaller inhibitory effect on ATP-induced A-M dissociation, kT (39 ± 2%). Sucrose had no noticeable effect on any other step in the ATPase reaction. In SiMBA, sucrose had a relatively small effect on the diffusion coefficient for actin fragments (25 ± 2%), and with stopped flow we showed that sucrose increased the activation energy barrier for A-M strong binding by 37 ± 3%, indicating that sucrose inhibits the rate of A-M strong binding by slowing bond formation more than diffusional searching. The inhibitory effects of sucrose on the rate of A-M rigor binding (71%) are comparable in magnitude to sucrose’s effects on both V (79 ± 33% decrease) and maximal actin-activated ATPase, kcat, (81 ± 16% decrease), indicating that the rate of A-M strong bond formation significantly influences both kcat and V. PMID:24370736

  16. Sugaring the pill: ethics and uncertainties in the use of sucrose for newborn infants.

    PubMed

    Wilkinson, Dominic J C; Savulescu, Julian; Slater, Rebeccah

    2012-07-01

    Sucrose is widely used for the management of procedural pain in newborn infants, including capillary blood sampling, venepuncture, and vascular cannulation. Multiple randomized controlled trials have demonstrated that sweet-tasting solutions reduce behavioral responses to acute painful stimuli. It has been claimed that sucrose should be a standard of care in neonatal units and that further placebo-controlled trials of sucrose are unnecessary and unethical. However, recently published data cast doubt on the analgesic properties of sucrose. We review this new evidence and analyze the philosophical and ethical questions that it raises, including the "problem of other minds." Sugar may be better understood not as an analgesic, removing or relieving pain, but as a compensating pleasure. There is a need for further research on the mechanism of sucrose's effect on pain behavior and on the long-term effects of sucrose treatment. Such trials will require comparison with placebo or with other interventions. Given uncertainty about the benefit of sucrose, it may be wise to use alternative analgesics or nonpharmacological interventions where these are available and appropriate. Sucrose may not be the answer to procedural pain in newborns.

  17. 40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Sucrose octanoate esters; exemption... FOOD Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of...

  18. 40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Sucrose octanoate esters; exemption... FOOD Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of...

  19. 40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Sucrose octanoate esters; exemption... FOOD Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of...

  20. 40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Sucrose octanoate esters; exemption... FOOD Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of...

  1. 40 CFR 180.1222 - Sucrose octanoate esters; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Sucrose octanoate esters; exemption... FOOD Exemptions From Tolerances § 180.1222 Sucrose octanoate esters; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of...

  2. 78 FR 66743 - Draft Guidance for Industry on Bioequivalence Recommendations for Iron Sucrose; Availability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-06

    ... the Federal Register of June 11, 2010 (75 FR 33311), FDA announced the availability of a guidance for... Recommendations for Iron Sucrose; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY... entitled ``Bioequivalence Recommendations for Iron Sucrose.'' The recommendations provide specific...

  3. 77 FR 18827 - Draft Guidance for Industry on Bioequivalence Recommendations for Iron Sucrose Injection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... Federal Register of June 11, 2010 (75 FR 33311), FDA announced the availability of a guidance for industry... Recommendations for Iron Sucrose Injection; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice... industry entitled ``Bioequivalence Recommendations for Iron Sucrose.'' The recommendations provide...

  4. Repeated Cocaine Experience Facilitates Sucrose-Reinforced Operant Responding in Enriched and Isolated Rats

    ERIC Educational Resources Information Center

    Klein, Emily D.; Gehrke, Brenda J.; Green, Thomas A.; Zentall, Thomas R.; Bardo, Michael T.

    2007-01-01

    The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30)…

  5. Phenotypic and Genotypic Characterization of Virulent Yersinia enterocolitica Strains Unable To Ferment Sucrose

    PubMed Central

    Guiyoule, Annie; Guinet, Françoise; Martin, Liliane; Benoit, Catherine; Desplaces, Nicole; Carniel, Elisabeth

    1998-01-01

    Several atypical sucrose-negative Yersinia strains, isolated from clinical samples and sometimes associated with symptoms, proved to have full virulence potential in in vitro and in vivo testings. DNA-relatedness studies revealed that they were authentic Yersinia enterocolitica strains. Therefore, atypical sucrose-negative Yersinia isolates should be analyzed for their virulence potential. PMID:9705424

  6. An in vivo invertebrate evaluation system for identifying substances that suppress sucrose-induced postprandial hyperglycemia

    PubMed Central

    Matsumoto, Yasuhiko; Ishii, Masaki; Sekimizu, Kazuhisa

    2016-01-01

    Sucrose is a major sweetener added to various foods and beverages. Excessive intake of sucrose leads to increases in blood glucose levels, which can result in the development and exacerbation of lifestyle-related diseases such as obesity and diabetes. In this study, we established an in vivo evaluation system using silkworms to explore substances that suppress the increase in blood glucose levels caused by dietary intake of sucrose. Silkworm hemolymph glucose levels rapidly increased after intake of a sucrose-containing diet. Addition of acarbose or voglibose, α-glycosidase inhibitors clinically used for diabetic patients, suppressed the dietary sucrose-induced increase in the silkworm hemolymph glucose levels. Screening performed using the sucrose-induced postprandial hyperglycemic silkworm model allowed us to identify some lactic acid bacteria that inhibit the increase in silkworm hemolymph glucose levels caused by dietary intake of sucrose. The inhibitory effects of the Lactococcus lactis #Ll-1 bacterial strain were significantly greater than those of different strains of lactic acid bacteria. No effect of the Lactococcus lactis #Ll-1 strain was observed in silkworms fed a glucose diet. These results suggest that the sucrose diet-induced postprandial hyperglycemic silkworm is a useful model for evaluating chemicals and lactic acid bacteria that suppress increases in blood glucose levels. PMID:27194587

  7. Water-solid interactions in amorphous maltodextrin-crystalline sucrose binary mixtures.

    PubMed

    Ghorab, Mohamed K; Toth, Scott J; Simpson, Garth J; Mauer, Lisa J; Taylor, Lynne S

    2014-03-01

    Amorphous and crystalline solids are commonly found together in a variety of pharmaceutical and food products. In this study, the influence of co-formulation of amorphous maltodextrins (MDs) and crystalline sucrose (S) on moisture sorption, deliquescence, and glass transition (Tg) properties of powder blends was investigated. Individual components and binary mixtures of four different molecular weight MDs with sucrose in 1:1 w/w ratios were exposed to various relative humidity (RH) environments and their equilibrium and dynamic moisture contents were monitored. The deliquescence point (RH0) and dissolution behavior of sucrose alone and in blends was also monitored by polarized light microscopy and second harmonic generation imaging. In S:MD blends, the deliquescence RH of sucrose was lower than the RH0 of sucrose alone, and synergistic moisture sorption also occurred at RHs lower than the RH0. Intimate contact of sucrose crystals with the amorphous MDs resulted in complete dissolution of sucrose at RH < RH0. When blends were stored at conditions exceeding the Tg of the individual MDs (25 °C and 60%, 49% and 34%RH for MD21, MD29 and MD40, respectively), the Tg of the blends was lower than that of individual MDs. Thus, co-formulation of amorphous MDs with crystalline sucrose sensitizes the blend to moisture, potentially leading to deleterious changes in the formulation if storage conditions are not adequately controlled.

  8. Sucrose regulation of ADP-glucose pyrophosphorylase subunit genes transcript levels in leaves and fruits

    NASA Technical Reports Server (NTRS)

    Li, Xiangyang; Xing, Jinpeng; Gianfagna, Thomas J.; Janes, Harry W.

    2002-01-01

    ADP-glucose pyrophosphorylase (AGPase, EC2.7.7.27) is a key regulatory enzyme in starch biosynthesis. The enzyme is a heterotetramer with two S and two B subunits. In tomato, there are three multiple forms of the S subunit gene. Agp S1, S2 and B are highly expressed in fruit from 10 to 25 days after anthesis. Agp S3 is only weakly expressed in fruit. Sucrose significantly elevates expression of Agp S1, S2 and B in both leaves and fruits. Agp S1 exhibits the highest degree of regulation by sucrose. In fact, sucrose may be required for Agp S1 expression. For excised leaves incubated in water, no transcripts for Agp S1 could be detected in the absence of sucrose, whereas it took up to 16 h in water before transcripts were no longer detectable for Agp S2 and B. Neither Agp S3 nor the tubulin gene is affected by sucrose, demonstrating that this response is specifically regulated by a carbohydrate metabolic signal, and is not due to a general increase in metabolism caused by sucrose treatment. Truncated versions of the promoter for Agp S1 indicate that a specific region 1.3-3.0 kb upstream from the transcription site is responsible for sucrose sensitivity. This region of the S1 promoter contains several cis-acting elements present in the promoters of other genes that are also regulated by sucrose. c2002 Elsevier Science Ireland Ltd. All rights reserved.

  9. Detection of sucrose content of sugar beet by visible/near-infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sucrose content is the most important quality parameter in the production and processing of sugar beet. This paper reports on the application of visible/near-infrared (Vis-NIR) spectroscopy for measurement of the sucrose content of sugar beet. Two portable spectrometers, covering the spectral region...

  10. Rats’ preferences for high fructose corn syrup vs. sucrose and sugar mixtures

    PubMed Central

    Ackroff, Karen; Sclafani, Anthony

    2011-01-01

    High fructose corn syrup (HFCS) has replaced sucrose in many food products, which has prompted research comparing these two sweeteners in rodents. The present study examined the relative palatability of HFCS and sucrose for rats, offering 11% carbohydrate solutions to match the content of common beverages for human consumption. The animals initially preferred HFCS to sucrose but after separate experience with each solution they switched to sucrose preference. Approximating the composition of HFCS with a mixture of fructose and glucose (55:45) yielded a solution that was less attractive than sucrose or HFCS. However, HFCS contains a small amount of glucose polymers, which are very attractive to rats. A 55:42:3 mixture of fructose, glucose and glucose polymers (Polycose) was equally preferred to HFCS and was treated similarly to HFCS in comparisons vs. sucrose. Post-oral effects of sucrose, which is 50% fructose and 50% glucose, may be responsible for the shift in preference with experience. This shift, and the relatively small magnitude of differences in preference for HFCS and sucrose, suggest that palatability factors probably do not contribute to any possible difference in weight gain responses to these sweeteners. PMID:21236278

  11. Evidence for the presence of a sucrose carrier in immature sugar-beet roots

    SciTech Connect

    Lemoine, R.; Daie, J.; Wyse, R.

    1987-04-01

    Unlike in mature sugar-beet roots, sucrose is assumed to be hydrolyzed by a wall-bound invertase prior to uptake by immature roots. To test this hypothesis, they used a sucrose analog, 1'fluorosucrose which is recognized by the carrier but is a poor substrate for invertases. Asymmetrically labeled sucrose (/sup 3/H-fructose) 1'fluorosucrose (/sup 14/C-glucose) were applied at 10 mM (/sup 3/H//sup 14/C=1) to an attached source leaf. After 6 h, sugars from plant parts in the translocation path were separated on HPLC. /sup 14/C-1'fluorosucrose was translocated and accumulated in the root at a higher rate than /sup 3/H-sucrose due to greater metabolism of /sup 3/H-sucrose in the shoot (indicated by the presence of /sup 3/H in hexose fractions and loss of asymmetry). In the root 25% of the /sup 3/H-sucrose was hydrolyzed to hexoses whereas no /sup 14/C was detected in hexose fractions. The data indicate that despite high cell-wall invertase and cytoplasmic sucrose synthase activities, young sugar-beet roots import and store sucrose without hydrolysis. Therefore, the function of a group translocator at the tonoplast is unclear.

  12. Rats' preferences for high fructose corn syrup vs. sucrose and sugar mixtures.

    PubMed

    Ackroff, Karen; Sclafani, Anthony

    2011-03-28

    High fructose corn syrup (HFCS) has replaced sucrose in many food products, which has prompted research comparing these two sweeteners in rodents. The present study examined the relative palatability of HFCS and sucrose for rats, offering 11% carbohydrate solutions to match the content of common beverages for human consumption. The animals initially preferred HFCS to sucrose but after separate experience with each solution they switched to sucrose preference. Approximating the composition of HFCS with a mixture of fructose and glucose (55:45) yielded a solution that was less attractive than sucrose or HFCS. However, HFCS contains a small amount of glucose polymers, which are very attractive to rats. A 55:42:3 mixture of fructose, glucose and glucose polymers (Polycose) was equally preferred to HFCS and was treated similarly to HFCS in comparisons vs. sucrose. Post-oral effects of sucrose, which is 50% fructose and 50% glucose, may be responsible for the shift in preference with experience. This shift, and the relatively small magnitude of differences in preference for HFCS and sucrose, suggest that palatability factors probably do not contribute to any possible difference in weight gain responses to these sweeteners.

  13. Diminished Reactivity of Postmature Human Infants to Sucrose Compared with Term Infants.

    ERIC Educational Resources Information Center

    Smith, Barbara A.; And Others

    1992-01-01

    This study of healthy 39-week-old infants, so-called term infants, and chronically stressed 42-week-old infants, so-called postmature infants, showed that sucrose was extremely effective in calming term infants but less effective in calming postmature infants. Results supported the hypothesis that sucrose engages an opioid system in infants. (BG)

  14. The correction factors for sucrose gap measurements and their practical applications.

    PubMed Central

    Jirounek, P; Jones, G J; Burckhardt, C W; Straub, R W

    1981-01-01

    The distribution of extracellular and intracellular potential in the sucrose gap apparatus, previously established for a single fiber using the cable equations for a core conductor model (Jirounek and Straub, Biophys. J., 11:1, 1971), is obtained for a multifiber preparation. The exact equation is derived relating the true membrane potential change to the measured potential differences across the sucrose gap, the junction potentials between sucrose and physiological solution, the membrane potential in the sucrose region, and the electrical parameters of the preparation in each region of the sucrose gap. The extracellular potential distribution has been measured using a modified sucrose gap apparatus for the frog sciatic nerve and the rabbit vagus nerve. The results indicate a hyperpolarization of the preparations in the sucrose region, of 60--75 mV. The hyperpolarization is independent of the presence of junction potentials. The calculation of the correction terms in the equation relating the actual to the measured potential change is illustrated for the case of complete depolarization by KC1 on one side of the sucrose gap. The correction terms in the equation are given for various experimental conditions, and a number of nomographic charts are presented, by means of which the correction factors can be rapidly evaluated. PMID:6974012

  15. The response of crying newborns to sucrose: is it a "sweetness" effect?

    PubMed

    Barr, R G; Pantel, M S; Young, S N; Wright, J H; Hendricks, L A; Gravel, R

    1999-05-01

    Intraoral sucrose (and other sweet carbohydrates) induce rapid and sustained calming in crying newborns and transiently increase mouthing and hand-mouth contact ("sucrose effects"). To investigate whether these effects are due to the sweetness of sucrose, 60 crying newborns were randomized to receive 250 microL of 24% sucrose solution, 0.12% of aspartame solution of equivalent sweetness (to adults), or 24% polycose, a soluble carbohydrate that is only very slightly sweet (to adults), as well as water in a mixed parallel crossover design. Relative to water, sucrose persistently reduced crying, and transiently increased mouthing and hand-mouth contact, as previously demonstrated. Aspartame also reduced crying, and transiently increased mouthing and hand-mouth contact, virtually mimicking the time course and the magnitude of the effects obtained in response to sucrose. By contrast, polycose solution had no specific effects on crying, mouthing, or hand-mouth contact. The results imply that the responses of crying newborns to intraoral sucrose are neither specific to sucrose nor to the general class of carbohydrates, and that these effects are more appropriately understood as "sweetness" effects.

  16. Non Linear Conjugate Gradient

    2006-11-17

    Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less

  17. Pronounced Phenotypic Changes in Transgenic Tobacco Plants Overexpressing Sucrose Synthase May Reveal a Novel Sugar Signaling Pathway

    PubMed Central

    Nguyen, Quynh Anh; Luan, Sheng; Wi, Seung G.; Bae, Hanhong; Lee, Dae-Seok; Bae, Hyeun-Jong

    2016-01-01

    Soluble sugars not only serve as nutrients, but also act as signals for plant growth and development, but how sugar signals are perceived and translated into physiological responses in plants remains unclear. We manipulated sugar levels in transgenic plants by overexpressing sucrose synthase (SuSy), which is a key enzyme believed to have reversible sucrose synthesis and sucrose degradation functions. The ectopically expressed SuSy protein exhibited sucrose-degrading activity, which may change the flux of sucrose demand from photosynthetic to non-photosynthetic cells, and trigger an unknown sucrose signaling pathway that lead to increased sucrose content in the transgenic plants. An experiment on the transition from heterotrophic to autotrophic growth demonstrated the existence of a novel sucrose signaling pathway, which stimulated photosynthesis, and enhanced photosynthetic synthesis of sucrose, which was the direct cause or the sucrose increase. In addition, a light/dark time treatment experiment, using different day length ranges for photosynthesis/respiration showed the carbohydrate pattern within a 24-h day and consolidated the role of sucrose signaling pathway as a way to maintain sucrose demand, and indicated the relationships between increased sucrose and upregulation of genes controlling development of the shoot apical meristem (SAM). As a result, transgenic plants featured a higher biomass and a shorter time required to switch to reproduction compared to those of control plants, indicating altered phylotaxis and more rapid advancement of developmental stages in the transgenic plants. PMID:26793204

  18. Copper-induced alteration in sucrose partitioning and its relationship to the root growth of two Elsholtzia haichowensis Sun populations.

    PubMed

    Li, Min-Jing; Xiong, Zhi-Ting; Liu, Hui; Kuo, Yi-Ming; Tong, Lei

    2016-10-01

    Hydroponic culture was used to comparatively investigate the copper (Cu)-induced alteration to sucrose metabolism and biomass allocation in two Elsholtzia haichowensis Sun populations with one from a Cu-contaminated site (CS) and the other from a non-contaminated site (NCS). Experimental results revealed that biomass allocation preferred roots over shoots in CS population, and shoots over roots in NCS population under Cu exposure. The difference in biomass allocation was correlated with the difference in sucrose partitioning between the two populations. Cu treatment (45 μM) significantly decreased leaf sucrose content and increased root sucrose content in CS population as a result of the increased activities of leaf sucrose synthesis enzymes (sucrose phosphate synthetase and sucrose synthase) and root sucrose cleavage enzyme (vacuolar invertase), which led to increased sucrose transport from leaves to roots. In contrast, higher Cu treatment increased sucrose content in leaves and decreased sucrose content in roots in NCS population as a result of the decreased activities of root sucrose cleavage enzymes (vacuolar and cell wall invertases) that led to less sucrose transport from leaves to roots. These results provide important insights into carbon resource partitioning and biomass allocation strategies in metallophytes and are beneficial for the implementation of phytoremediation techniques. PMID:27153457

  19. Uptake of arsenic by alkaline soils near alkaline coal fly ash disposal facilities.

    PubMed

    Khodadoust, Amid P; Theis, Thomas L; Murarka, Ishwar P; Naithani, Pratibha; Babaeivelni, Kamel

    2013-12-01

    The attenuation of arsenic in groundwater near alkaline coal fly ash disposal facilities was evaluated by determining the uptake of arsenic from ash leachates by surrounding alkaline soils. Ten different alkaline soils near a retired coal fly ash impoundment were used in this study with pH ranging from 7.6 to 9.0, while representative coal fly ash samples from two different locations in the coal fly ash impoundment were used to produce two alkaline ash leachates with pH 7.4 and 8.2. The arsenic found in the ash leachates was present as arsenate [As(V)]. Adsorption isotherm experiments were carried out to determine the adsorption parameters required for predicting the uptake of arsenic from the ash leachates. For all soils and leachates, the adsorption of arsenic followed the Langmuir and Freundlich equations, indicative of the favorable adsorption of arsenic from leachates onto all soils. The uptake of arsenic was evaluated as a function of ash leachate characteristics and the soil components. The uptake of arsenic from alkaline ash leachates, which occurred mainly as calcium hydrogen arsenate, increased with increasing clay fraction of soil and with increasing soil organic matter of the alkaline soils. Appreciable uptake of arsenic from alkaline ash leachates with different pH and arsenic concentration was observed for the alkaline soils, thus attenuating the contamination of groundwater downstream of the retired coal fly ash impoundment.

  20. Generalized conjugate gradient squared

    SciTech Connect

    Fokkema, D.R.; Sleijpen, G.L.G.

    1994-12-31

    In order to solve non-symmetric linear systems of equations, the Conjugate Gradient Squared (CGS) is a well-known and widely used iterative method. In practice the method converges fast, often twice as fast as the Bi-Conjugate Gradient method. This is what you may expect, since CGS uses the square of the BiCG polynomial. However, CGS may suffer from its erratic convergence behavior. The method may diverge or the approximate solution may be inaccurate. BiCGSTAB uses the BiCG polynomial and a product of linear factors in an attempt to smoothen the convergence. In many cases, this has proven to be very effective. Unfortunately, the convergence of BiCGSTAB may stall when a linear factor (nearly) degenerates. BiCGstab({ell}) is designed to overcome this degeneration of linear factors. It generalizes BiCGSTAB and uses both the BiCG polynomial and a product of higher order factors. Still, CGS may converge faster than BiCGSTAB or BiCGstab({ell}). So instead of using a product of linear or higher order factors, it may be worthwhile to look for other polynomials. Since the BiCG polynomial is based on a three term recursion, a natural choice would be a polynomial based on another three term recursion. Possibly, a suitable choice of recursion coefficients would result in method that converges faster or as fast as CGS, but less erratic. It turns out that an algorithm for such a method can easily be formulated. One particular choice for the recursion coefficients leads to CGS. Therefore one could call this algorithm generalized CGS. Another choice for the recursion coefficients leads to BiCGSTAB. It is therefore possible to mix linear factors and some polynomial based on a three term recursion. This way one may get the best of both worlds. The authors will report on their findings.

  1. Improved dose sensitivity of normoxic polyacrylamide gelatin gel dosimeter with sucrose

    NASA Astrophysics Data System (ADS)

    Yoshioka, M.; Hayashi, S.; Usui, S.; Haneda, K.; Kondo, T.; Numasaki, H.; Teshima, T.; Tominaga, T.

    2010-11-01

    To improve the dose sensitivity of normoxic polyacrylamide gelatin gel (nPAG) dosimeter, the effect of sucrose as an additive is investigated. The dose-transverse relaxation rate (R2) characteristics of the samples of nPAG with different sucrose concentrations were examined, and temperature increases due to exothermic polymerization reaction in the irradiated gel were also measured. As the result, the dose-R2 sensitivity increased (~3 times) with increasing sucrose concentrations (0-25%), while other characteristics of dose response, such as dose integral property, dose rate dependence and temporal stability, were consistent with those of typical nPAG dosimeter. And as the sucrose concentrations increased, a larger temperature increase was observed. These results clearly indicate that the polymerization rate is increased with increasing sucrose concentrations.

  2. Influence of sugars and hormones on the genes involved in sucrose metabolism in maize endosperms.

    PubMed

    Ren, X D; Liu, H M; Liu, Y H; Hu, Y F; Zhang, J J; Huang, Y B

    2015-01-01

    Starch is the major storage product in the endosperm of cereals. Its synthesis is closely related to sucrose metabolism. In our previous study, we found that the expression of most of the genes involved in starch synthesis might be regulated by sugars and hormones in the maize endosperm. However, little is known regarding the transcriptional regulation of genes involved in sucrose metabolism. Thus, in this study, maize endosperms were treated with different sugars and hormones and the expression of genes involved in sucrose metabolism (including synthesis, degradation, and transport) were evaluated using real-time quantitative reverse transcription-polymerase chain reaction. We found that genes affected by different sugars and hormones were primarily regulated by abscisic acid. Sucrose and abscisic acid showed an additive effect on the expression of some genes. Differences in the transcriptional regulation of genes involved in sucrose metabolism and starch biosynthesis were observed. PMID:25867309

  3. Effect of raffinose on sucrose recrystallization and textural changes in soft cookies.

    PubMed

    Belcourt, Laura A; Labuza, Theodore P

    2007-01-01

    Sucrose recrystallization and the release of moisture that occurs as molecules of sugar are incorporated into a growing crystal lattice have been hypothesized as the cause of firming in soft cookies over time. Raffinose, a trisaccharide and known sucrose crystallization inhibitor, was tested as a means to inhibit or slow this process. Texture changes in the cookies were quantified using peak force measurements obtained by employing a puncture test. Sucrose recrystallization was successfully suppressed by the addition of 5% raffinose (w/w), as demonstrated by quantitative results obtained using powder x-ray diffraction and the degree of crystallization correlated with texture. Cookies with added raffinose were found to be significantly softer in texture, as well as having significantly decreased quantities of recrystallized sucrose. The hypothesis that sucrose recrystallization is responsible in part for the firming of cookies was shown to be logical.

  4. Similarity assessment and attribute scaling of sucrose and aspartame in grape drink.

    PubMed

    Christensen, L; Archer, S

    1990-02-01

    The present study investigated the perception of sweetness of aspartame in comparison to various concentrations of sucrose. Twenty-seven subjects were randomly assigned to taste a chilled or room temperature Kool-Aid beverage sweetened with either aspartame or five different concentrations of sucrose. Subjects assessed the perceived similarity in sweetness of an aspartame-aspartame pair and five different aspartame-sucrose pairings and rated each beverage on five bipolar adjectives. Analysis of the similarity ratings revealed that subjects did not perceive the pairs of beverages to differ in perceived sweetness. Analysis of the adjective ratings revealed that aspartame and the lower sucrose concentrations were perceived as being less sweet and more sour than the higher sucrose concentrations.

  5. Sucrose Transporter AtSUC9 Mediated by a Low Sucrose Level is Involved in Arabidopsis Abiotic Stress Resistance by Regulating Sucrose Distribution and ABA Accumulation.

    PubMed

    Jia, Wanqiu; Zhang, Lijun; Wu, Di; Liu, Shan; Gong, Xue; Cui, Zhenhai; Cui, Na; Cao, Huiying; Rao, Longbing; Wang, Che

    2015-08-01

    Sucrose (Suc) transporters (SUCs or SUTs) are important regulators in plant growth and stress tolerance. However, the mechanism of SUCs in plant abiotic stress resistance remains to be dietermined. Here, we found that AtSUC9 expression was induced by abiotic stress, including salt, osmotic and cold stress conditions. Disruption of AtSUC9 led to sensitive responses to abiotic stress during seed germination and seedling growth. Further analyses indicated that the sensitivity phenotype of Atsuc9 mutants resulted from higher Suc content in shoots and lower Suc content in roots, as compared with that in wild-type (WT) plants. In addition, we found that the expression of AtSUC9 is induced in particular by low levels of exogenous and endogenous Suc, and deletion of AtSUC9 affected the expression of the low Suc level-responsive genes. AtSUC9 also showed an obvious response to treatments with low concentrations of exogenous Suc during seed germination, seedling growth and Suc distribution, and Atsuc9 mutants hardly grew in abiotic stress treatments without exogenous Suc. Moreover, our results illustrated not only that deletion of AtSUC9 blocks abiotic stress-inducible ABA accumulation but also that Atsuc9 mutants had a lower content of endogenous ABA in stress conditions than in normal conditions. Deletion of AtSUC9 also inhibited the expression of many ABA-inducible genes (SnRk2.2/3/6, ABF2/3/4, ABI1/3/4, RD29A, KIN1 and KIN2). These results indicate that AtSUC9 is induced in particular by low Suc levels then mediates the balance of Suc distribution and promotes ABA accumulation to enhance Arabidopsis abiotic stress resistance.

  6. An efficient protocol to enhance the extracellular production of recombinant protein from Escherichia coli by the synergistic effects of sucrose, glycine, and Triton X-100.

    PubMed

    Bao, Ru-Meng; Yang, Hong-Ming; Yu, Chang-Mei; Zhang, Wei-Fen; Tang, Jin-Bao

    2016-10-01

    Targeting recombinant proteins at highly extracellular production in the culture medium of Escherichia coli presents a significant advantage over cytoplasmic or periplasmic expression. In this work, a recombinant protein between ZZ protein and alkaline phosphatase (rZZ-AP) was constructed. Because rZZ-AP has the IgG-binding capacity and enzymatic activity, it can serve as an immunoreagent in immunoassays. However, only a very small portion of rZZ-AP is generally secreted into the aqueous medium under conventional cultivation procedure. Hence, we emphasized on the optimization of the culture procedures and attempted to dramatically enhance the yield of extracellular rZZ-AP from E. coli HB101 host cells by adding sucrose, glycine, and Triton X-100 in the culture medium. Results showed that the extracellular production of rZZ-AP in the culture medium containing 5% sucrose, 1% glycine, and 1% Triton X-100 was 18.6 mg/l, which was 18.6-fold higher than that without the three chemicals. And the β-galactosidase activity test showed that the increased extracellular rZZ-AP was not due to cell lysis. Further analysis suggested a significant interaction effect among the three chemicals for the enhancement of extracellular production. Ultrastructural analysis indicated that the enhancement may be due to the influence of sucrose, glycine, and Triton X-100 on the periplasmic osmolality, permeability, or integrity of the cell wall, respectively. This proposed approach presents a simple strategy to enhance the extracellular secretion of recombinant proteins in the E. coli system at the process of cell cultivation.

  7. EMF radiations (1800 MHz)-inhibited early seedling growth of maize (Zea mays) involves alterations in starch and sucrose metabolism.

    PubMed

    Kumar, Arvind; Singh, Harminder Pal; Batish, Daizy R; Kaur, Shalinder; Kohli, Ravinder Kumar

    2016-07-01

    The present study investigated the impact of 1800-MHz electromagnetic field radiations (EMF-r), widely used in mobile communication, on the growth and activity of starch-, sucrose-, and phosphate-hydrolyzing enzymes in Zea mays seedlings. We exposed Z. mays to modulated continuous wave homogenous EMF-r at specific absorption rate (SAR) of 1.69±0.0 × 10(-1) W kg(-1) for ½, 1, 2, and 4 h. The analysis of seedlings after 7 days revealed that short-term exposure did not induce any significant change, while longer exposure of 4 h caused significant growth and biochemical alterations. There was a reduction in the root and coleoptile length with more pronounced effect on coleoptile growth (23 % reduction on 4-h exposure). The contents of photosynthetic pigments and total carbohydrates declined by 13 and 18 %, respectively, in 4-h exposure treatments compared to unexposed control. The activity of starch-hydrolyzing enzymes-α- and β-amylases-increased by ∼92 and 94 %, respectively, at an exposure duration of 4 h, over that in the control. In response to 4-h exposure treatment, the activity of sucrolytic enzymes-acid invertases and alkaline invertases-was increased by 88 and 266 %, whereas the specific activities of phosphohydrolytic enzymes (acid phosphatases and alkaline phosphatases) showed initial increase up to ≤2 h duration and then declined at >2 h exposure duration. The study concludes that EMF-r-inhibited seedling growth of Z. mays involves interference with starch and sucrose metabolism. PMID:26277350

  8. Sucrose hydrolases from the midgut of the sugarcane stalk borer Diatraea saccharalis.

    PubMed

    Carneiro, Cíntia N B; Isejima, Eliza M; Samuels, Richard I; Silva, Carlos P

    2004-11-01

    A beta-fructosidase (EC 3.2.1.26) was isolated from the midgut of larval sugar cane stalk borer Diatraea saccharalis by mild-denaturing electrophoresis and further purified to near homogeneity by gel filtration. beta-Fructosidase hydrolysed sucrose, raffinose and the fructosyl-trisaccharide isokestose, but it had no activity against maltose, melibiose and synthetic substrates for alpha-glucosidases. Two other sucrose hydrolases, one resembling a alpha-glucosidase (EC 3.2.1.20) and the other one active specifically against sucrose (sucrase) were detected in the larval midgut of D. saccharalis. All three sucrose hydrolases were associated with the midgut epithelium of larval D. saccharalis. Relative molecular mass (M(r)) of the beta-fructosidase was estimated around 45,000 (by gel filtration). The other two sucrose hydrolases had M(r) of 54,000 (alpha-glucosidase) and 59,000 (sucrase). The pH optima of the sucrose hydrolases were 5-10 for both alpha-glucosidase and sucrase and 7-8 for beta-fructosidase. Considering V(max)/K(m) ratios, beta-fructosidase preferentially cleaves isokestose rather than raffinose and sucrose. In order to evaluate the possible contribution of microorganisms isolated from the midgut to the pool of sucrose hydrolases, washed midgut epithelia were homogenised and plated onto appropriate media. Seven bacterial and one yeast species were isolated. None of the sucrose hydrolases extracted from the microorganisms corresponded to the enzymes isolated from midgut tissue homogenates. This result suggests that the major sucrose hydrolases found in the midgut of larval D. saccharalis were probably produced by the insect themselves not by the gut microflora.

  9. Interaction of Metabolic Stress with Chronic Mild Stress in Altering Brain Cytokines and Sucrose Preference

    PubMed Central

    Remus, Jennifer L.; Stewart, Luke T.; Camp, Robert M.; Novak, Colleen M.; Johnson, John D.

    2015-01-01

    There is growing evidence that metabolic stressors increase an organism’s risk of depression. Chronic mild stress is a popular animal model of depression and several serendipitous findings have suggested that food deprivation prior to sucrose testing in this model is necessary to observe anhedonic behaviors. Here, we directly tested this hypothesis by exposing animals to chronic mild stress and used an overnight two bottle sucrose test (food ad libitum) on day 5 and 10, then food and water deprive animals overnight and tested their sucrose consumption and preference in a 1h sucrose test the following morning. Approximately 65% of stressed animals consumed sucrose and showed a sucrose preference similar to non-stressed controls in an overnight sucrose test, while 35% showed a decrease in sucrose intake and preference. Following overnight food and water deprivation the previously ‘resilient’ animals showed a significant decrease in sucrose preference and greatly reduced sucrose intake. In addition, we evaluated whether the onset of anhedonia following food and water deprivation corresponds to alterations in corticosterone, epinephrine, circulating glucose, or interleukin-1 beta expression in limbic brain areas. While all stressed animals showed adrenal hypertrophy and elevated circulating epinephrine, only stressed animals that were food deprived were hypoglycemic compared to food deprived controls. Additionally, food and water deprivation significantly increased hippocampus IL-1β while food and water deprivation only increased hypothalamus IL-1β in stress susceptible animals. These data demonstrate that metabolic stress of food and water deprivation interacts with chronic stressor exposure to induce physiological and anhedonic responses. PMID:25914924

  10. Interaction of metabolic stress with chronic mild stress in altering brain cytokines and sucrose preference.

    PubMed

    Remus, Jennifer L; Stewart, Luke T; Camp, Robert M; Novak, Colleen M; Johnson, John D

    2015-06-01

    There is growing evidence that metabolic stressors increase an organism's risk of depression. Chronic mild stress is a popular animal model of depression and several serendipitous findings have suggested that food deprivation prior to sucrose testing in this model is necessary to observe anhedonic behaviors. Here, we directly tested this hypothesis by exposing animals to chronic mild stress and used an overnight 2-bottle sucrose test (food ad libitum) on Day 5 and 10, then food and water deprive animals overnight and tested their sucrose consumption and preference in a 1-hr sucrose test the following morning. Approximately 65% of stressed animals consumed sucrose and showed a sucrose preference similar to nonstressed controls in an overnight sucrose test, and 35% showed a decrease in sucrose intake and preference. Following overnight food and water deprivation the previously "resilient" animals showed a significant decrease in sucrose preference and greatly reduced sucrose intake. In addition, we evaluated whether the onset of anhedonia following food and water deprivation corresponds to alterations in corticosterone, epinephrine, circulating glucose, or interleukin-1 beta (IL-1β) expression in limbic brain areas. Although all stressed animals showed adrenal hypertrophy and elevated circulating epinephrine, only stressed animals that were food deprived were hypoglycemic compared with food-deprived controls. Additionally, food and water deprivation significantly increased hippocampus IL-1β while food and water deprivation only increased hypothalamus IL-1β in stress-susceptible animals. These data demonstrate that metabolic stress of food and water deprivation interacts with chronic stressor exposure to induce physiological and anhedonic responses.

  11. Transcriptome Analysis of Sucrose Metabolism during Bulb Swelling and Development in Onion (Allium cepa L.)

    PubMed Central

    Zhang, Chunsha; Zhang, Hongwei; Zhan, Zongxiang; Liu, Bingjiang; Chen, Zhentai; Liang, Yi

    2016-01-01

    Allium cepa L. is a widely cultivated and economically significant vegetable crop worldwide, with beneficial dietary and health-related properties, but its sucrose metabolism is still poorly understood. To analyze sucrose metabolism during bulb swelling, and the development of sweet taste in onion, a global transcriptome profile of onion bulbs was undertaken at three different developmental stages, using RNA-seq. A total of 79,376 unigenes, with a mean length of 678 bp, was obtained. In total, 7% of annotated Clusters of Orthologous Groups (COG) were involved in carbohydrate transport and metabolism. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, “starch and sucrose metabolism” (147, 2.40%) constituted the primary metabolism pathway in the integrated library. The expression of sucrose transporter genes was greatest during the early-swelling stage, suggesting that sucrose transporters (SUTs) participated in sucrose metabolism mainly at an early stage of bulb development. A gene-expression analysis of the key enzymes of sucrose metabolism suggested that sucrose synthase, cell wall invertase, and invertase were all likely to participate in the hydrolysis of sucrose, generating glucose, and fructose. In addition, trehalose was hydrolyzed to two molecules of glucose by trehalase. From 15 to 40 days after swelling (DAS), both the glucose and fructose contents of bulbs increased, whereas the sucrose content decreased. The growth rate between 15 and 30 DAS was slower than that between 30 and 40 DAS, suggesting that the latter was a period of rapid expansion. The dataset generated by our transcriptome profiling will provide valuable information for further research. PMID:27713754

  12. Sugarcane ShSUT1: analysis of sucrose transport activity and inhibition by sucralose.

    PubMed

    Reinders, Anke; Sivitz, Alicia B; Hsi, Alex; Grof, Christopher P L; Perroux, Jai M; Ward, John M

    2006-10-01

    Plant sucrose transporters (SUTs) are members of the glycoside-pentoside-hexuronide (GPH) cation symporter family (TC2.A.2) that is part of the major facilitator superfamily (MFS). All plant SUTs characterized to date function as proton-coupled symporters and catalyze the cellular uptake of sucrose. SUTs are involved in loading sucrose into the phloem and sink tissues, such as seeds, roots and flowers. Because monocots are agriculturally important, SUTs from cereals have been the focus of recent research. Here we present a functional analysis of the SUT ShSUT1 from sugarcane, an important crop species grown for its ability to accumulate high amounts of sucrose in the stem. ShSUT1 was previously shown to be expressed in maturing stems and plays an important role in the accumulation of sucrose in this tissue. Using two-electrode voltage clamping in Xenopus oocytes expressing ShSUT1, we found that ShSUT1 is highly selective for sucrose, but has a relatively low affinity for sucrose (K(0.5) = 8.26 mM at pH 5.6 and a membrane potential of -137 mV). We also found that the sucrose analog sucralose (4,1',6'-trichloro-4,1',6'-trideoxy-galacto-sucrose) is a competitive inhibitor of ShSUT1 with an inhibition coefficient (K(i)) of 16.5 mM. The presented data contribute to our understanding of sucrose transport in plants in general and in monocots in particular.

  13. Sucrose importation into laticifers of Hevea brasiliensis, in relation to ethylene stimulation of latex production

    PubMed Central

    Dusotoit-Coucaud, Anaïs; Brunel, Nicole; Kongsawadworakul, Panida; Viboonjun, Unchera; Lacointe, André; Julien, Jean-Louis; Chrestin, Hervé; Sakr, Soulaïman

    2009-01-01

    Background and Aims The major economic product of Hevea brasiliensis is a rubber-containing cytoplasm (latex), which flows out of laticifers (latex cells) when the bark is tapped. The latex yield is stimulated by ethylene. Sucrose, the unique precursor of rubber synthesis, must cross the plasma membrane through specific sucrose transporters before being metabolized in the laticifers. The relative importance of sucrose transporters in determining latex yield is unknown. Here, the effects of ethylene (by application of Ethrel®) on sucrose transporter gene expression in the inner bark tissues and latex cells of H. brasiliensis are described. Methods Experiments, including cloning sucrose transporters, real time RT-PCR and in situ hybridization, were carried out on virgin (untapped) trees, treated or untreated with the latex yield stimulant Ethrel. Key Results Seven putative full-length cDNAs of sucrose transporters were cloned from a latex-specific cDNA library. These transporters belong to all SUT (sucrose transporter) groups and differ by their basal gene expression in latex and inner soft bark, with a predominance of HbSUT1A and HbSUT1B. Of these sucrose transporters, only HbSUT1A and HbSUT2A were distinctly increased by ethylene. Moreover, this increase was shown to be specific to laticifers and to ethylene application. Conclusion The data and all previous information on sucrose transport show that HbSUT1A and HbSUT2A are related to the increase in sucrose import into laticifers, required for the stimulation of latex yield by ethylene in virgin trees. PMID:19567416

  14. Escherichia coli W shows fast, highly oxidative sucrose metabolism and low acetate formation.

    PubMed

    Arifin, Yalun; Archer, Colin; Lim, SooA; Quek, Lake-Ee; Sugiarto, Haryadi; Marcellin, Esteban; Vickers, Claudia E; Krömer, Jens O; Nielsen, Lars K

    2014-11-01

    Sugarcane is the most efficient large-scale crop capable of supplying sufficient carbon substrate, in the form of sucrose, needed during fermentative feedstock production. However, sucrose metabolism in Escherichia coli is not well understood because the two most common strains, E. coli K-12 and B, do not grow on sucrose. Here, using a sucrose utilizing strain, E. coli W, we undertake an in-depth comparison of sucrose and glucose metabolism including growth kinetics, metabolite profiling, microarray-based transcriptome analysis, labelling-based proteomic analysis and (13)C-fluxomics. While E. coli W grew comparably well on sucrose and glucose integration of the omics, datasets showed that during growth on each carbon source, metabolism was distinct. The metabolism was generally derepressed on sucrose, and significant flux rearrangements were observed in central carbon metabolism. These included a reduction in the flux of the oxidative pentose phosphate pathway branch, an increase in the tricarboxylic acid cycle flux and a reduction in the glyoxylate shunt flux due to the dephosphorylation of isocitrate dehydrogenase. But unlike growth on other sugars that induce cAMP-dependent Crp regulation, the phosphoenol-pyruvate-glyoxylate cycle was not active on sucrose. Lower acetate accumulation was also observed in sucrose compared to glucose cultures. This was linked to induction of the acetate catabolic genes actP and acs and independent of the glyoxylic shunt. Overall, the cells stayed highly oxidative. In summary, sucrose metabolism was fast, efficient and led to low acetate accumulation making it an ideal carbon source for industrial fermentation with E. coli W. PMID:25125039

  15. Hydration properties and the role of water in taste modalities of sucrose, caffeine, and sucrose-caffeine mixtures.

    PubMed

    Aroulmoji, V; Hutteau, F; Mathlouthi, M; Rutledge, D N

    2001-08-01

    Solution properties of sapid molecules are informative on their type of hydration (hydrophobic or hydrophilic) and on the extent of the hydration layer. Physicochemical properties (intrinsic viscosity and apparent specific volume) and nuclear magnetic resonance (NMR) relaxation rates R(1) and R(2) for pure sucrose, bitter molecule caffeine, and their mixture were found to be relevant in the interpretation of the effects of these solutes on water mobility. Likewise, surface tension, contact angles with a hydrophobic surface, and the adhesion forces to this type of surface of the aqueous solutions of sapid molecules were found to discriminate between their effects on water cohesion and also between their taste qualities. The interpretation of the two sets of independent experimental results, namely physicochemical and spectroscopic data, helps in the elucidation of the role of water in sweet and bitter taste chemoreception. PMID:11513707

  16. Identification of actively filling sucrose sinks. [Solanum tuberosum; Phaseolus lunatus; Manihot esculenta; Liquidambar styraciflua L. ; Carya illinoinensis

    SciTech Connect

    Sung, Shijean S.; Xu, Dianpeng; Black C.C. )

    1989-04-01

    Certain actively filling plant sucrose sinks such as a seed, a tuber, or a root can be identified by measuring the uridine diphosphate and pyrophosphate-dependent metabolism of sucrose. Sucrolysis in both active and quiescent sucrose sinks was tested and sucrose synthase was found to be the predominant sucrose breakdown activity. Sucrolysis via invertases was low and secondary in both types of sinks. Sucrose synthase activity dropped markedly, greater than fivefold, in quiescent sinks. The test are consistent with the hypothesis that the sucrose filling activity, i.e. the sink strength, of these plant sinks can be measured by testing the uridine diphosphate and pyrophosphate-dependent breakdown of sucrose. Measuring the initial reactions of sucrolysis shows much promise for use in agriculture crop and tree improvement research as a biochemical test for sink strength.

  17. Inactivation of a heterocyst-specific invertase indicates a principal role of sucrose catabolism in heterocysts of Anabaena sp.

    PubMed

    López-Igual, Rocío; Flores, Enrique; Herrero, Antonia

    2010-10-01

    Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that carries out N(2) fixation in specialized cells called heterocysts, which exchange nutrients and regulators with the filament's vegetative cells that perform the photosynthetic fixation of CO(2). The Anabaena genome carries two genes coding for alkaline/neutral invertases, invA and invB. As shown by Northern analysis, both genes were expressed monocistronically and induced under nitrogen deprivation, although induction was stronger for invB than for invA. Whereas expression of an InvA-N-GFP fusion (green fluorescent protein [GFP] fused to the N terminus of the InvA protein [InvA-N]) was homogeneous along the cyanobacterial filament, consistent with the lack of dependence on HetR, expression of an InvB-N-GFP fusion upon combined nitrogen deprivation took place mainly in differentiating and mature heterocysts. In an hetR genetic background, the InvB-N-GFP fusion was strongly expressed all along the filament. An insertional mutant of invA could grow diazotrophically but was impaired in nifHDK induction and exhibited an increased frequency of heterocysts, suggesting a regulatory role of the invertase-mediated carbon flux in vegetative cells. In contrast, an invB mutant was strongly impaired in diazotrophic growth, showing a crucial role of sucrose catabolism mediated by the InvB invertase in the heterocysts.

  18. Gradient boosting machines, a tutorial

    PubMed Central

    Natekin, Alexey; Knoll, Alois

    2013-01-01

    Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods with a strong focus on machine learning aspects of modeling. A theoretical information is complemented with descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. Three practical examples of gradient boosting applications are presented and comprehensively analyzed. PMID:24409142

  19. Photoelastic response of alkaline earth aluminosilicate glasses.

    PubMed

    Smedskjaer, Morten M; Saxton, Scott A; Ellison, Adam J; Mauro, John C

    2012-02-01

    Understanding the structural origins of the photoelastic response in oxide glasses is important for discovering new families of zero-stress optic glasses and for developing a predictive physical model. In this Letter, we have investigated the composition dependence of the stress optic coefficient C of 32 sodium aluminosilicate glasses with different types of alkaline earth oxides (MgO, CaO, SrO, and BaO). We find that most of the composition dependence of the stress optic response can be captured by a linear regression model and that the individual contributions from the alkaline earths to C depend on the alkaline earth-oxygen bond metallicity. High bond metallicity is required to allow bonds to be distorted along both the bonding direction and perpendicular to it. These findings are valuable for understanding the photoelastic response of oxide glasses.

  20. Expression analysis of genes associated with sucrose accumulation in sugarcane (Saccharum spp. hybrids) varieties differing in content and time of peak sucrose storage.

    PubMed

    Chandra, A; Verma, P K; Islam, M N; Grisham, M P; Jain, R; Sharma, A; Roopendra, K; Singh, K; Singh, P; Verma, I; Solomon, S

    2015-05-01

    Sucrose synthesis/accumulation in sugarcane is a complex process involving many genes and regulatory sequences that control biochemical events in source-sink tissues. Among these, sucrose synthase (SuSy), sucrose phosphate synthase (SPS), soluble acid (SAI) and cell wall (CWI) invertases are important. Expression of these enzymes was compared in an early (CoJ64) and late (BO91) maturing sugarcane variety using end-point and qRT-PCR. Quantitative RT-PCR at four crop stages revealed high CWI expression in upper internodes of CoJ64, which declined significantly in both top and bottom internodes with maturity. In BO91, CWI expression was high in top and bottom internodes and declined significantly only in top internodes as the crop matured. Overall, CWI expression was higher in CoJ64 than in BO91. During crop growth, there was no significant change in SPS expression in bottom internodes in CoJ64, whereas in BO91 it decreased significantly. Apart from a significant decrease in expression of SuSy in mature bottom internodes of BO91, there was no significant change. Similar SAI expression was observed with both end-point and RT-PCR, except for significantly increased expression in top internodes of CoJ64 with maturity. SAI, being a major sucrose hydrolysing enzyme, was also monitored with end-point PCR expression in internode tissues of CoJ64 and BO91, with higher expression of SAI in BO91 at early crop stages. Enzyme inhibitors, e.g. manganese chloride (Mn(++) ), significantly suppressed expression of SAI in both early- and late-maturing varieties. Present findings enhance understanding of critical sucrose metabolic gene expression in sugarcane varieties differing in content and time of peak sucrose storage. Thus, through employing these genes, improvement of sugarcane sucrose content is possible.

  1. Use of the Biphasic 13C-Sucrose/Glucose Breath Test to Assess Sucrose Maldigestion in Adults with Functional Bowel Disorders

    PubMed Central

    Balesh, Albert M.; Shelby, Harold T.

    2016-01-01

    Sucrase insufficiency has been observed in children with of functional bowel disorders (FBD) and symptoms of dietary carbohydrate intolerance may be indistinguishable from those of FBD. A two-phase 13C-sucrose/13C-glucose breath test (13C-S/GBT) was used to assess sucrase activity because disaccharidase assays are seldom performed in adults. When 13C-sucrose is hydrolyzed to liberate monosaccharides, oxidation to 13CO2 is a proportional indicator of sucrase activity. Subsequently, 13C-glucose oxidation rate was determined after a secondary substrate ingestion (superdose) to adjust for individual habitus effects (Phase II). 13CO2 enrichment recovery ratio from 13C-sucrose and secondary 13C-glucose loads reflect the individualized sucrase activity [Coefficient of Glucose Oxidation for Sucrose (CGO-S)]. To determine if sucrase insufficiency could be a factor in FBD, 13C-S/GBT was validated using subjects with known sucrase gene mutation status by comparing 13CO2-breath enrichment with plasma 13C-glucose enrichment. 13C-S/GBT was used to assess sucrose digestion in FBD patients and asymptomatic controls. 13CO2-breath enrichment correlated with the appearance of 13C-sucrose-derived glucose in plasma (r2 = 0.80). Mean, control group CGO-S-enrichment outcomes were 1.01 at 60′, 0.92 at 75′, and 0.96 at mean 60′–75′ with normal CGO-S defined as >0.85 (95% C.I.). In contrast, FBD patients demonstrated lower CGO-S values of 0.77 at 60′, 0.77 at 75′, and 0.76 at mean 60′–75′ (Chi Square: 6.55; p < 0.01), which points to sucrose maldigestion as a cause of FBD. PMID:27579322

  2. Use of the Biphasic (13)C-Sucrose/Glucose Breath Test to Assess Sucrose Maldigestion in Adults with Functional Bowel Disorders.

    PubMed

    Opekun, Antone R; Balesh, Albert M; Shelby, Harold T

    2016-01-01

    Sucrase insufficiency has been observed in children with of functional bowel disorders (FBD) and symptoms of dietary carbohydrate intolerance may be indistinguishable from those of FBD. A two-phase (13)C-sucrose/(13)C-glucose breath test ((13)C-S/GBT) was used to assess sucrase activity because disaccharidase assays are seldom performed in adults. When (13)C-sucrose is hydrolyzed to liberate monosaccharides, oxidation to (13)CO2 is a proportional indicator of sucrase activity. Subsequently, (13)C-glucose oxidation rate was determined after a secondary substrate ingestion (superdose) to adjust for individual habitus effects (Phase II). (13)CO2 enrichment recovery ratio from (13)C-sucrose and secondary (13)C-glucose loads reflect the individualized sucrase activity [Coefficient of Glucose Oxidation for Sucrose (CGO-S)]. To determine if sucrase insufficiency could be a factor in FBD, (13)C-S/GBT was validated using subjects with known sucrase gene mutation status by comparing (13)CO2-breath enrichment with plasma (13)C-glucose enrichment. (13)C-S/GBT was used to assess sucrose digestion in FBD patients and asymptomatic controls. (13)CO2-breath enrichment correlated with the appearance of (13)C-sucrose-derived glucose in plasma (r (2) = 0.80). Mean, control group CGO-S-enrichment outcomes were 1.01 at 60', 0.92 at 75', and 0.96 at mean 60'-75' with normal CGO-S defined as >0.85 (95% C.I.). In contrast, FBD patients demonstrated lower CGO-S values of 0.77 at 60', 0.77 at 75', and 0.76 at mean 60'-75' (Chi Square: 6.55; p < 0.01), which points to sucrose maldigestion as a cause of FBD. PMID:27579322

  3. Alkaline Capacitors Based on Nitride Nanoparticles

    NASA Technical Reports Server (NTRS)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  4. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    DOEpatents

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  5. BIOGEOCHEMICAL GRADIENTS AS A FRAMEWORK FOR UNDERSTANDING WASTE SITE EVOLUTION

    SciTech Connect

    Denham, M; Karen Vangelas, K

    2008-10-17

    The migration of biogeochemical gradients is a useful framework for understanding the evolution of biogeochemical conditions in groundwater at waste sites contaminated with metals and radionuclides. This understanding is critical to selecting sustainable remedies and evaluating sites for monitored natural attenuation, because most attenuation mechanisms are sensitive to geochemical conditions such as pH and redox potential. Knowledge of how gradients in these parameters evolve provides insights into the behavior of contaminants with time and guides characterization, remedy selection, and monitoring efforts. An example is a seepage basin site at the Savannah River Site in South Carolina where low-level acidic waste has seeped into groundwater. The remediation of this site relies, in part, on restoring the natural pH of the aquifer by injecting alkaline solutions. The remediation will continue until the pH up-flow of the treatment zone increases to an acceptable value. The time required to achieve this objective depends on the time it takes the trailing pH gradient, the gradient separating the plume from influxing natural groundwater, to reach the treatment zone. Predictions of this length of time will strongly influence long-term remedial decisions.

  6. Possible interference between tissue-non-specific alkaline phosphatase with an Arg54-->Cys substitution and acounterpart with an Asp277-->Ala substitution found in a compound heterozygote associated with severe hypophosphatasia.

    PubMed Central

    Fukushi-Irié, M; Ito, M; Amaya, Y; Amizuka, N; Ozawa, H; Omura, S; Ikehara, Y; Oda, K

    2000-01-01

    Tissue-non-specific alkaline phosphatase (TNSALP) with an Arg(54)-->Cys (R54C) or an Asp(277)-->Ala (D277A)substitution was found in a patient with hypophosphatasia [Henthorn,Raducha, Fedde, Lafferty and Whyte (1992) Proc. Natl. Acad. Sci. U.S.A.89, 9924-9928]. To examine effects of these missense mutations onproperties of TNSALP, the TNSALP mutants were expressed ectopically inCOS-1 cells. The wild-type TNSALP was synthesized as a 66-kDa endo-beta-N-acetylglucosaminidase H (Endo H)-sensitive form, and processed to an 80-kDa mature form, which is anchored to the plasma membrane via glycosylphosphatidylinositol (GPI). Although the mutant proteins were found to be modified by GPI, digestion with phosphatidylinositol-specific phospholipase C, cell-surface biotinylation and immunofluorescence observation demonstrated that the cell-surface appearance of TNSALP (R54C) and TNSALP (D277A) was either almost totally or partially retarded respectively. The 66-kDa Endo H-sensitive band was the only form, and was rapidly degraded in the cells expressing TNSALP (R54C). In contrast with cells expressing TNSALP(R54C), where alkaline phosphatase activity was negligible, significant enzyme activity was detected and, furthermore, the 80-kDa mature form appeared on the surface of the cells expressing TNSALP (D277A). Analysis by sedimentation on sucrose gradients showed that a considerable fraction of newly synthesized TNSALP (R54C) and TNSALP(D277A) formed large aggregates, indicating improper folding and incorrect oligomerization of the mutant enzymes. When co-expressed with TNSALP (R54C), the level of the 80-kDa mature form of TNSALP (D277A)was decreased dramatically, with a concomitant reduction in enzyme activity in the co-transfected cell. These findings suggest that TNSALP(R54C) interferes with folding and assembly of TNSALP (D277A) intrans when expressed in the same cell, thus probably explaining why a compound heterozygote for these mutant alleles developed severe

  7. Sucrose Concentration at the Apoplastic Interface between Seed Coat and Cotyledons of Developing Soybean Seeds

    PubMed Central

    Gifford, Roger M.; Thorne, John H.

    1985-01-01

    The apoplastic sucrose concentration at the interface between cotyledons and surrounding seed coats of developing soybeans (Glycine max L. Merr. cv Wye) was found by three indirect methods to be in the range of 150 to 200 millimolar. This is an order of magnitude higher than has been reported elsewhere for soybean. It was also higher than the overall sucrose concentrations in the cotyledons and seed coats, each of which was approximately 90 millimolar. By defoliating plants 24 hours before measurement, both the overall sucrose concentration in the cotyledons and the interfacial apoplastic sucrose concentration were reduced by three-fourths. However, there was no day/night difference in overall tissue sucrose concentration of cotyledons or seed coats from intact plants suggesting the existence of a homeostatic mechanism compensating for the diurnal photosynthetic cycle. About 7 hours were required for a tritiated polyethylene glycol-900 solution to fully permeate developing cotyledons (from ∼220 milligram fresh weight embryos), implying high diffusion resistance through the tissue. These results indicate that a high interfacial sucrose concentration may exist in vivo. They suggest that the saturable carrier-mediated component of sucrose uptake may be of little physiological significance in the outermost cell layers of the cotyledons. PMID:16664151

  8. Skin permeation enhancement by sucrose esters: a pH-dependent phenomenon.

    PubMed

    Cázares-Delgadillo, J; Naik, A; Kalia, Y N; Quintanar-Guerrero, D; Ganem-Quintanar, A

    2005-06-13

    The purpose of the present study was to evaluate the effect of sucrose esters (particularly, sucrose laureate and sucrose oleate in Transcutol) on the percutaneous penetration of a charged molecule as a function of ionization. We have investigated the influence of these sucrose esters on the in vitro diffusion profiles of lidocaine hydrochloride, a weak ionizable base (pKa=7.9), at different pH values, using porcine ear skin as the barrier membrane. As expected, lidocaine flux in the absence of an enhancer, increased from pH 5 to 9 with a corrresponding increase in the level of the unionized base. However, when skin was pretreated with 2% laureate in Transcutol (2% L-TC), drug permeation was higher at pH 5.0 and 7.0 than at 9.0. A different trend was observed in experiments with 2% oleate in Transcutol (2% O-TC), where skin flux was maximal at a more basic pH, when the degree of ionization is low. The results suggest that sucrose laureate enhances the penetration of the ionized form of the drug (12-fold greater flux relative to control), whereas sucrose oleate is more effective in promoting permeation of the unionized species. The structural properties of the sucrose esters as well as the degree of ionization of the drug are important characteristics affecting the transdermal flux of lidocaine.

  9. Differential motivational profiles following adolescent sucrose access in male and female rats.

    PubMed

    Reichelt, Amy C; Abbott, Kirsten N; Westbrook, R Fred; Morris, Margaret J

    2016-04-01

    Adolescents are the highest consumers of sugar sweetened drinks. Excessive consumption of such drinks is a likely contributor to the development of obesity and may be associated with enduring changes in the systems involved in reward and motivation. We examined the impact of daily sucrose consumption in young male and female rats (N=12 per group) across the adolescent period on the motivation to perform instrumental responses to gain food rewards as adults. Rats were or were not exposed to a sucrose solution for 2 h each day for 28 days across adolescence [postnatal days (P) 28-56]. They were then trained as adults (P70 onward) to lever press for a palatable 15% cherry flavored sucrose reward and tested on a progressive ratio (PR) schedule to assess motivation to respond for reinforcement. Female rats exposed to sucrose had higher breakpoints on the PR schedule than controls, whereas male rats exposed to sucrose had lower breakpoints than controls. These results show that consumption of sucrose during adolescence produced sex-specific behavioral changes in responding for sucrose as adults. PMID:26826605

  10. Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm - caries model.

    PubMed

    Botelho, Juliana Nunes; Villegas-Salinas, Mario; Troncoso-Gajardo, Pía; Giacaman, Rodrigo Andrés; Cury, Jaime Aparecido

    2016-05-20

    Sucrose is the most cariogenic dietary carbohydrate and starch is considered non-cariogenic for enamel and moderately cariogenic for dentine. However, the cariogenicity of the combination of starch and sucrose remains unclear. The aim of this study was to evaluate the effect of this combination on Streptococcus mutans biofilm composition and enamel and dentine demineralization. Biofilms of S. mutans UA159 were grown on saliva-coated enamel and dentine slabs in culture medium containing 10% saliva. They were exposed (8 times/day) to one of the following treatments: 0.9% NaCl (negative control), 1% starch, 10% sucrose, or 1% starch and 10% sucrose (starch + sucrose). To simulate the effect of human salivary amylase on the starch metabolization, the biofilms were pretreated with saliva before each treatment and saliva was also added to the culture medium. Acidogenicity of the biofilm was estimated by evaluating (2 times/day) the culture medium pH. After 4 (dentine) or 5 (enamel) days of growth, biofilms (n = 9) were individually collected, and the biomass, viable microorganism count, and polysaccharide content were quantified. Dentine and enamel demineralization was assessed by determining the percentage of surface hardness loss. Biofilms exposed to starch + sucrose were more acidogenic and caused higher demineralization (p < 0.0001) on either enamel or dentine than those exposed to each carbohydrate alone. The findings suggest that starch increases the cariogenic potential of sucrose. PMID:27223133

  11. Promotion of Flowering in Brassica campestris L. cv Ceres by Sucrose

    PubMed Central

    Friend, Douglas J. C.; Bodson, Monique; Bernier, Georges

    1984-01-01

    Flower initiation of the quantitative long-day plant Brassica campestris cv Ceres was earlier and at a lower final leaf number when sucrose was added to the medium in which plants were grown in sterile culture. The optimal concentration of sucrose was 40 to 80 millimolar. This flower-promoting effect of sucrose was not osmotic, as mannitol, sodium chloride, and polyethylene glycol were not effective at equal osmotic potentials. Seedlings grown heterotrophically after treatment with 4-chloro-5-(dimethylamino)-2-phenyl-3-(2H)-pyridazinone to prevent chlorophyll accumulation were also induced to form flower primordia earlier as the sucrose concentration in the medium was increased up to 80 millimolar. Inclusion of 4 millimolar sodium nitrate in the culture medium of green plants did not reduce the flower-promoting effects of sucrose but delayed initiation in plants grown without added sucrose. Removal of CO2 during a single main or supplementary light period, or both, greatly reduced flower initiation. It is concluded that sucrose may be an important controlling factor determining floral initiation in Brassica. PMID:16663739

  12. Physical properties and consumer liking of cookies prepared by replacing sucrose with tagatose.

    PubMed

    Taylor, T P; Fasina, O; Bell, L N

    2008-04-01

    The objective of this study was to investigate the suitability of tagatose, a minimally absorbed prebiotic monosaccharide, as a replacement for sucrose in cookies. A sucrose-containing cookie recipe was prepared as the control. Sucrose was replaced with tagatose at various levels ranging from 25% to 100%. Cookies containing fructose were also prepared for comparison due to the structural similarities between tagatose and fructose. The rheological properties of the dough were measured using texture profile analysis. The baked cookies were evaluated for spread, color, and hardness. For tagatose-containing cookies, the extent of likeness was evaluated by 53 untrained panelists using a 9-point hedonic scale. When sucrose was replaced by tagatose, doughs with similar rheological properties to the control resulted. The tagatose-containing cookies were harder and darker with a lower spread than the control. Sensory data indicated that panelists liked the brown color of the 100% tagatose cookies better than the control, but disliked their sweetness. Overall likeness scores of the control and cookies made by replacing half of the sucrose with tagatose were the same. Tagatose appears to be suitable as a partial replacer for sucrose in cookies based on similar dough properties, cookie properties, and likeness scores. Using tagatose to replace sucrose in foods would reduce the amount of metabolizeable sugars in the diet as well as provide the desirable prebiotic effect.

  13. Maltodextrin can produce similar metabolic and cognitive effects to those of sucrose in the rat.

    PubMed

    Kendig, Michael D; Lin, Candy S; Beilharz, Jessica E; Rooney, Kieron B; Boakes, Robert A

    2014-06-01

    In the context of the well-documented metabolic and behavioural effects of supplementing rats' diets with access to a sucrose solution, the aim of this study was to compare the impact of 10% sucrose with that of an isoenergetic (10.4%) solution of hydrolysed starch, maltodextrin. This polysaccharide is metabolised at least as rapidly as sucrose and is also very palatable to rats, but does not contain fructose. Each of three experiments contained three groups: one given a sucrose solution, one given a maltodextrin solution and a control group maintained on standard chow and water alone. In Experiment 1 the sucrose and maltodextrin groups were given their supplementary drinks for 2 h each day, while in Experiments 2 and 3 these groups had 24-h access to their supplements. Ad libitum access to maltodextrin produced at least as rapid weight gain as sucrose and in Experiment 2 retroperitoneal fat mass was greater in the two carbohydrate groups than in the control group. Moreover, in Experiment 3, impaired performance on a location recognition task was also found in both carbohydrate groups after only 17 days on the diets. These results indicate that the harmful effects of excess sucrose consumption can also be produced by another rapidly absorbed carbohydrate that does not contain fructose.

  14. Density Gradients in Chemistry Teaching

    ERIC Educational Resources Information Center

    Miller, P. J.

    1972-01-01

    Outlines experiments in which a density gradient might be used to advantage. A density gradient consists of a column of liquid, the composition and density of which varies along its length. The procedure can be used in analysis of solutions and mixtures and in density measures of solids. (Author/TS)

  15. Empirical equation estimates geothermal gradients

    SciTech Connect

    Kutasov, I.M. )

    1995-01-02

    An empirical equation can estimate geothermal (natural) temperature profiles in new exploration areas. These gradients are useful for cement slurry and mud design and for improving electrical and temperature log interpretation. Downhole circulating temperature logs and surface outlet temperatures are used for predicting the geothermal gradients.

  16. Multilayer High-Gradient Insulators

    SciTech Connect

    Harris, J R

    2006-08-16

    Multilayer High-Gradient Insulators are vacuum insulating structures composed of thin, alternating layers of dielectric and metal. They are currently being developed for application to high-current accelerators and related pulsed power systems. This paper describes some of the High-Gradient Insulator research currently being conducted at Lawrence Livermore National Laboratory.

  17. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    PubMed Central

    Schwalfenberg, Gerry K.

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine. PMID:22013455

  18. Differential effects of sucrose and fructose on dietary obesity in four mouse strains

    PubMed Central

    Glendinnning, John I.; Breinager, Lindsey; Kyrillou, Emily; Lacuna, Kristine; Rocha, Rotsen; Sclafani, Anthony

    2010-01-01

    We examined sugar-induced obesity in mouse strains polymorphic for Tas1r3, a gene that codes for the T1R3 sugar taste receptor. The T1R3 receptor in the FVB and B6 strains has a higher affinity for sugars than that in the AKR and 129P3 strains. In Experiment 1, mice had 40 days of access to lab chow plus water, sucrose (10 or 34%), or fructose (10 or 34%) solutions. The strains consumed more of the sucrose than isocaloric fructose solutions. The pattern of strain differences in caloric intake from the 10% sugar solutions was FVB > 129P3 = B6 > AKR; and that from the 34% sugar solutions was FVB > 129P3 > B6 ≥ AKR. Despite consuming more sugar calories, the FVB mice resisted obesity altogether. The AKR and 129P3 mice became obese exclusively on the 34% sucrose diet, while the B6 mice did so on the 34% sucrose and 34% fructose diets. In Experiment 2, we compared total caloric intake from diets containing chow versus chow plus 34% sucrose. All strains consumed 15-29% more calories from the sucrose-supplemented diet. In Experiment 3, we compared the oral acceptability of the sucrose and fructose solutions, using lick tests. All strains licked more avidly for the 10% sucrose solutions. The results indicate that in mice (a) Tas1r3 genotype does not predict sugar-induced hyperphagia or obesity; (b) sucrose solutions stimulate higher daily intakes than isocaloric fructose solutions; and (c) susceptibility to sugar-induced obesity varies with strain, sugar concentration and sugar type. PMID:20600198

  19. Sucrose-induced analgesia during early life modulates adulthood learning and memory formation.

    PubMed

    Nuseir, Khawla Q; Alzoubi, Karem H; Alabwaini, Jehad; Khabour, Omar F; Kassab, Manal I

    2015-06-01

    This study is aimed at examining the long-term effects of chronic pain during early life (postnatal day 0 to 8weeks), and intervention using sucrose, on cognitive functions during adulthood in rats. Pain was induced in rat pups via needle pricks of the paws. Sucrose solution or paracetamol was administered for analgesia before the paw prick. Control groups include tactile stimulation to account for handling and touching the paws, and sucrose alone was used. All treatments were started on day one of birth and continued for 8weeks. At the end of the treatments, behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM), as well as pain threshold via foot-withdrawal response to a hot plate apparatus. Additionally, the hippocampus was dissected, and blood was collected. Levels of neurotrophins (BDNF, IGF-1 and NT-3) and endorphins were assessed using ELISA. The results show that chronic noxious stimulation resulted in comparable foot-withdrawal latency between noxious and tactile groups. On the other hand, pretreatment with sucrose or paracetamol increased pain threshold significantly both in naive rats and noxiously stimulated rats (P<0.05). Chronic pain during early life impaired short-term memory, and sucrose treatment prevented such impairment (P<0.05). Sucrose significantly increased serum levels of endorphin and enkephalin. Chronic pain decreased levels of BDNF in the hippocampus and this decrease was prevented by sucrose and paracetamol treatments. Hippocampal levels of NT-3 and IGF-1 were not affected by any treatment. In conclusion, chronic pain induction during early life induced short memory impairment, and pretreatment with sucrose prevented this impairment via mechanisms that seem to involve BDNF. As evident in the results, sucrose, whether alone or in the presence of pre-noxious stimulation, increases pain threshold in such circumstances; most likely via a mechanism that involves an increase in endogenous

  20. Differential effects of sucrose and fructose on dietary obesity in four mouse strains.

    PubMed

    Glendinning, John I; Breinager, Lindsey; Kyrillou, Emily; Lacuna, Kristine; Rocha, Rotsen; Sclafani, Anthony

    2010-10-01

    We examined sugar-induced obesity in mouse strains polymorphic for Tas1r3, a gene that codes for the T1R3 sugar taste receptor. The T1R3 receptor in the FVB and B6 strains has a higher affinity for sugars than that in the AKR and 129P3 strains. In Experiment 1, mice had 40days of access to lab chow plus water, sucrose (10 or 34%), or fructose (10 or 34%) solutions. The strains consumed more of the sucrose than isocaloric fructose solutions. The pattern of strain differences in caloric intake from the 10% sugar solutions was FVB>129P3=B6>AKR; and that from the 34% sugar solutions was FVB>129P3>B6>/=AKR. Despite consuming more sugar calories, the FVB mice resisted obesity altogether. The AKR and 129P3 mice became obese exclusively on the 34% sucrose diet, while the B6 mice did so on the 34% sucrose and 34% fructose diets. In Experiment 2, we compared total caloric intake from diets containing chow versus chow plus 34% sucrose. All strains consumed between 11 and 25% more calories from the sucrose-supplemented diet. In Experiment 3, we compared the oral acceptability of the sucrose and fructose solutions, using lick tests. All strains licked more avidly for the 10% sucrose solutions. The results indicate that in mice (a) Tas1r3 genotype does not predict sugar-induced hyperphagia or obesity; (b) sucrose solutions stimulate higher daily intakes than isocaloric fructose solutions; and (c) susceptibility to sugar-induced obesity varies with strain, sugar concentration and sugar type.

  1. Sucrose-induced analgesia during early life modulates adulthood learning and memory formation.

    PubMed

    Nuseir, Khawla Q; Alzoubi, Karem H; Alabwaini, Jehad; Khabour, Omar F; Kassab, Manal I

    2015-06-01

    This study is aimed at examining the long-term effects of chronic pain during early life (postnatal day 0 to 8weeks), and intervention using sucrose, on cognitive functions during adulthood in rats. Pain was induced in rat pups via needle pricks of the paws. Sucrose solution or paracetamol was administered for analgesia before the paw prick. Control groups include tactile stimulation to account for handling and touching the paws, and sucrose alone was used. All treatments were started on day one of birth and continued for 8weeks. At the end of the treatments, behavioral studies were conducted to test the spatial learning and memory using radial arm water maze (RAWM), as well as pain threshold via foot-withdrawal response to a hot plate apparatus. Additionally, the hippocampus was dissected, and blood was collected. Levels of neurotrophins (BDNF, IGF-1 and NT-3) and endorphins were assessed using ELISA. The results show that chronic noxious stimulation resulted in comparable foot-withdrawal latency between noxious and tactile groups. On the other hand, pretreatment with sucrose or paracetamol increased pain threshold significantly both in naive rats and noxiously stimulated rats (P<0.05). Chronic pain during early life impaired short-term memory, and sucrose treatment prevented such impairment (P<0.05). Sucrose significantly increased serum levels of endorphin and enkephalin. Chronic pain decreased levels of BDNF in the hippocampus and this decrease was prevented by sucrose and paracetamol treatments. Hippocampal levels of NT-3 and IGF-1 were not affected by any treatment. In conclusion, chronic pain induction during early life induced short memory impairment, and pretreatment with sucrose prevented this impairment via mechanisms that seem to involve BDNF. As evident in the results, sucrose, whether alone or in the presence of pre-noxious stimulation, increases pain threshold in such circumstances; most likely via a mechanism that involves an increase in endogenous

  2. Expression of Fos during sham sucrose intake in rats with central gustatory lesions.

    PubMed

    Mungarndee, Suriyaphun S; Lundy, Robert F; Norgren, Ralph

    2008-09-01

    For humans and rodents, ingesting sucrose is rewarding. This experiment tested the prediction that the neural activity produced by sapid sucrose reaches reward systems via projections from the pons through the limbic system. Gastric cannulas drained ingested fluid before absorption. For 10 days, the rats alternated an hour of this sham ingestion between sucrose and water. On the final test day, half of them sham drank water and the other half 0.6 M sucrose. Thirty minutes later, the rats were killed and their brains immunohistochemically stained for Fos. The groups consisted of controls and rats with excitotoxic lesions in the gustatory thalamus (TTA), the medial (gustatory) parabrachial nucleus (PBN), or the lateral (visceral afferent) parabrachial nucleus. In controls, compared with water, sham ingesting sucrose produced significantly more Fos-positive neurons in the nucleus of the solitary tract, PBN, TTA, and gustatory cortex (GC). In the ventral forebrain, sucrose sham licking increased Fos in the bed nucleus of the stria terminalis, central nucleus of amygdala, and the shell of nucleus accumbens. Thalamic lesions blocked the sucrose effect in GC but not in the ventral forebrain. After lateral PBN lesions, the Fos distributions produced by distilled H(2)O or sucrose intake did not differ from controls. Bilateral medial PBN damage, however, eliminated the sucrose-induced Fos increase not only in the TTA and GC but also in the ventral forebrain. Thus ventral forebrain areas associated with affective responses appear to be activated directly by PBN gustatory neurons rather than via the thalamocortical taste system. PMID:18635449

  3. Transcriptional coordination and abscisic acid mediated regulation of sucrose transport and sucrose-to-starch metabolism related genes during grain filling in wheat (Triticum aestivum L.).

    PubMed

    Mukherjee, Shalini; Liu, Aihua; Deol, Kirandeep K; Kulichikhin, Konstanin; Stasolla, Claudio; Brûlé-Babel, Anita; Ayele, Belay T

    2015-11-01

    Combining physiological, molecular and biochemical approaches, this study investigated the transcriptional coordination and abscisic acid (ABA) mediated regulation of genes involved in sucrose import and its conversion to starch during grain filling in wheat. Sucrose import appears to be mediated by seed localized TaSUT1, mainly TaSUT1D, while sucrose cleavage by TaSuSy2. Temporal overlapping of the transcriptional activation of AGPL1 and AGPS1a that encode AGPase with that of the above genes suggests their significance in the synthesis of ADP-glucose; TaAGPL1A and TaAGPL1D contributing the majority of AGPL1 transcripts. ABA induced repressions of TaSUT1, TaSuSy2, TaAGPL1 and TaAGPS1a imply that ABA negatively regulates sucrose import into the endosperm and its subsequent metabolism to ADP-glucose, the substrate for starch synthesis. The formations of amyloses and amylopectin from ADP-glucose appear to be mediated by specific members of GBSS, and SS, SBE and DBE gene families, and the ABA-induced transcriptional change in most of these genes implies that ABA regulates amylose and amylopectin synthesis. The findings provide insights into the molecular mechanisms underlying the coordination and ABA mediated regulation of sucrose transport into the developing endosperm and its subsequent metabolism to starch during grain filling in wheat.

  4. Effectiveness of oral sucrose for pain management in infants during immunizations.

    PubMed

    Curry, Donna Miles; Brown, Cindy; Wrona, Sharon

    2012-09-01

    This study examined the effects of oral sucrose as an analgesic agent during routine immunization for infants at 2, 4, and 6 months of age. A sample of 113 healthy infants were recruited from three ambulatory clinics and randomly assigned to one of three treatment groups. Infants were given 2 mL orally of either 50% sucrose, 75% sucrose, or sterile water 2 minutes before administration of immunizations. No significant difference was found among the different age groups with the different treatments for pain as measured with the FLACC scores and crying time. Consolability factors are felt to have some influence. PMID:22929601

  5. Biological Sensor for Sucrose Availability: Relative Sensitivities of Various Reporter Genes

    PubMed Central

    Miller, William G.; Brandl, Maria T.; Quiñones, Beatriz; Lindow, Steven E.

    2001-01-01

    A set of three sucrose-regulated transcriptional fusions was constructed. Fusions p61RYTIR, p61RYlac, and p61RYice contain the scrR sucrose repressor gene and the promoterless gfp, lacZ, and inaZ reporter genes, respectively, fused to the scrY promoter from Salmonella enterica serovar Typhimurium. Cells of Erwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. While a large variation in sucrose-dependent reporter gene activity was observed in cells harboring all gene fusions, fusions to the inaZ reporter gene yielded a much wider range of activity and were responsive to lower levels of sucrose than either lacZ or gfp. The lacZ reporter gene was found to be more efficient than gfp, requiring approximately 300-fold fewer cells for a detectable response over all concentrations of sucrose. Similarly, inaZ was found to be more efficient than lacZ, requiring 30-fold fewer cells at 1.45 μM sucrose and 6,100-fold fewer cells at 29 mM sucrose for a quantifiable response. The fluorescence of individual cells containing p61RYTIR was quantified following epifluorescence microscopy in order to relate the fluorescence exhibited by populations of cells in batch cultures with that of individual cells in such cultures. While the mean fluorescence intensity of a population of individual cells increased with increasing concentrations of sucrose, a wide range of fluorescence intensity was seen among individual cells. For most cultures the distribution of fluorescence intensity among individual cells was log-normally distributed, but cells grown in intermediate concentrations of sucrose exhibited two distinct populations of cells, one having relatively low fluorescence and another with much higher fluorescence. When cells were inoculated onto bean leaves, whole-cell ice nucleation and gfp-based biological sensors for sucrose each indicated that the average concentration of sucrose on moist leaf surfaces was about 20

  6. ISSUES WITH ALKALINE TREATMENT OF SLUDGE

    EPA Science Inventory

    This presentation begins with a discussion of the use of lime and other alkaline materials from the very earliest times to the present for killing bacteria, viruses and parasites and for controlling odors in wastewaters and sludge. It answers the question "How did EPA arrive at i...

  7. Alkaline electrochemical cells and method of making

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  8. Kinetics of the alkaline hydrolysis of nitrocellulose.

    PubMed

    Christodoulatos, C; Su, T L; Koutsospyros, A

    2001-01-01

    Cellulose nitrate (nitrocellulose) is an explosive solid substance used in large quantities in various formulations of rocket and gun propellants. Safe destruction of nitrocellulose can be achieved by alkaline hydrolysis, which converts it to biodegradable products that can then be treated by conventional biological processes. The kinetics of the alkaline hydrolysis of munitions-grade nitrocellulose in sodium hydroxide solutions were investigated in completely mixed batch reactors. Experiments were conducted using solutions of alkaline strength ranging from 0.1 to 15% by mass and temperatures in the range of 30 to 90 degrees C. Regression analysis of the kinetic data revealed that alkaline hydrolysis of nitrocellulose is of the order 1.0 and 1.5 with respect to nitrocellulose and hydroxide concentration, respectively. The activation energy of the hydrolysis reaction was found to be 100.9 kJ/mol with a preexponential Arrhenius constant of 4.73 x 10(13). Nitrite and nitrate, in a 3:1 ratio, were the primary nitrogen species present in the posthydrolysis solution. The kinetic information is pertinent to the development and optimization of nitrocellulose chemical-biological treatment systems.

  9. Alkaline Bohr effect of human hemoglobin Ao.

    PubMed

    Di Cera, E; Doyle, M L; Gill, S J

    1988-04-01

    Differential oxygen binding measurements obtained over the pH range 6.95 to 9.10 at 25 degrees C have allowed a detailed description of the alkaline Bohr effect of human hemoglobin Ao. Phenomenological analysis of the data in terms of the Adair equation shows that: (1) the oxygen binding curves are asymmetrical with the population of the triply oxygenated species being negligible throughout the pH range studied: (2) the shape of the oxygen binding curve is affected by pH, especially at low saturation; and (3) the maximum O2-proton linkage is -0.52 mole of proton per mole of oxygen at pH 7.4. A possible molecular mechanism of the Bohr effect is proposed within the framework of an allosteric model which accounts for the low population of triply oxygenated hemoglobin species. At least three Bohr groups are necessary for a quantitative description of the alkaline Bohr effect. Two of these groups titrate in the range of the His146 beta and Vall alpha residues, which have long been identified as the main alkaline Bohr groups, and altogether contribute 84% of the alkaline Bohr effect at physiological pH. A third ionizable group, linked to oxygenation presumably at the beta chains, is implicated and is titrated in a pH range characteristic of a surface histidyl residue.

  10. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS

    EPA Science Inventory

    The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-b...

  11. Use Alkalinity Monitoring to Optimize Bioreactor Performance.

    PubMed

    Jones, Christopher S; Kult, Keegan J

    2016-05-01

    In recent years, the agricultural community has reduced flow of nitrogen from farmed landscapes to stream networks through the use of woodchip denitrification bioreactors. Although deployment of this practice is becoming more common to treat high-nitrate water from agricultural drainage pipes, information about bioreactor management strategies is sparse. This study focuses on the use of water monitoring, and especially the use of alkalinity monitoring, in five Iowa woodchip bioreactors to provide insights into and to help manage bioreactor chemistry in ways that will produce desirable outcomes. Results reported here for the five bioreactors show average annual nitrate load reductions between 50 and 80%, which is acceptable according to established practice standards. Alkalinity data, however, imply that nitrous oxide formation may have regularly occurred in at least three of the bioreactors that are considered to be closed systems. Nitrous oxide measurements of influent and effluent water provide evidence that alkalinity may be an important indicator of bioreactor performance. Bioreactor chemistry can be managed by manipulation of water throughput in ways that produce adequate nitrate removal while preventing undesirable side effects. We conclude that (i) water should be retained for longer periods of time in bioreactors where nitrous oxide formation is indicated, (ii) measuring only nitrate and sulfate concentrations is insufficient for proper bioreactor operation, and (iii) alkalinity monitoring should be implemented into protocols for bioreactor management. PMID:27136151

  12. Use Alkalinity Monitoring to Optimize Bioreactor Performance.

    PubMed

    Jones, Christopher S; Kult, Keegan J

    2016-05-01

    In recent years, the agricultural community has reduced flow of nitrogen from farmed landscapes to stream networks through the use of woodchip denitrification bioreactors. Although deployment of this practice is becoming more common to treat high-nitrate water from agricultural drainage pipes, information about bioreactor management strategies is sparse. This study focuses on the use of water monitoring, and especially the use of alkalinity monitoring, in five Iowa woodchip bioreactors to provide insights into and to help manage bioreactor chemistry in ways that will produce desirable outcomes. Results reported here for the five bioreactors show average annual nitrate load reductions between 50 and 80%, which is acceptable according to established practice standards. Alkalinity data, however, imply that nitrous oxide formation may have regularly occurred in at least three of the bioreactors that are considered to be closed systems. Nitrous oxide measurements of influent and effluent water provide evidence that alkalinity may be an important indicator of bioreactor performance. Bioreactor chemistry can be managed by manipulation of water throughput in ways that produce adequate nitrate removal while preventing undesirable side effects. We conclude that (i) water should be retained for longer periods of time in bioreactors where nitrous oxide formation is indicated, (ii) measuring only nitrate and sulfate concentrations is insufficient for proper bioreactor operation, and (iii) alkalinity monitoring should be implemented into protocols for bioreactor management.

  13. Negative Electrode For An Alkaline Cell

    DOEpatents

    Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

    1998-07-14

    The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

  14. Gradient elution in capillary electrochromatography

    SciTech Connect

    Anex, D.; Rakestraw, D.J.; Yan, Chao; Dadoo, R.; Zare, R.N.

    1997-08-01

    In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

  15. Surfactant-enhanced alkaline flooding for light oil recovery. Quarterly report, April 1, 1995--June 30, 1995

    SciTech Connect

    Wasan, D.T.

    1995-09-01

    The overall objective of this project is to develop a very cost-effective method for formulating a successful surfactant-enhanced alkaline flood by appropriately choosing mixed alkalis which form inexpensive buffers to obtain the desired pH (between 8.5 and 12.0) for ultimate spontaneous emulsification and ultra-low tension. In addition, the novel concept of pH gradient design to optimize flood water conditions will be tested.

  16. Effects of Vacuum Impregnation with Sucrose Solution on Mango Tissue.

    PubMed

    Lin, Xian; Luo, Cailian; Chen, Yulong

    2016-06-01

    The influences of vacuum impregnation (VI) on the tissue of mango cubes during atmospheric immersion in sucrose solution were investigated. Results showed that VI effectively facilitated water loss (WL) and sugar gain (SG) during the 300min immersion process, with increases of 20.59% and 31.26%, respectively. A pectin solubilization/degradation phenomenon was observed in the immersion process. The intercellular space and cross section area in the VI-treated mango tissue increased immediately after being released to atmospheric pressure. And it was noted that after experiencing shrinkage-relaxation period twice in the 300 min immersion process, the size of VI-treated mango cells recovered to the original level of fresh ones. Major variations in WL, protopectin content, water soluble pectin content, firmness and microstructure of mango cubes appeared within the first 60 min. In addition, the firmness of mango cubes was positively correlated with the protopectin content (P < 0.01), but negatively correlated with WL and the water soluble pectin content (P < 0.01), indicating that WL and degradation of protopectin contributed greatly to the loss of firmness. PMID:27100561

  17. Decoding Neural Circuits that Control Compulsive Sucrose-Seeking

    PubMed Central

    Nieh, Edward H.; Matthews, Gillian A.; Allsop, Stephen A.; Presbrey, Kara N.; Leppla, Christopher A.; Wichmann, Romy; Neve, Rachael; Wildes, Craig P.; Tye, Kay M.

    2015-01-01

    The lateral hypothalamic (LH) projection to the ventral tegmental area (VTA) has been linked to reward processing, but the computations within the LH-VTA loop that give rise to specific aspects of behavior have been difficult to isolate. We show that LH-VTA neurons encode the learned action of seeking a reward, independent of reward availability. In contrast, LH neurons downstream of VTA encode reward-predictive cues and unexpected reward omission. We show that inhibiting the LH-VTA pathway reduces “compulsive” sucrose-seeking, but not food consumption in hungry mice. We reveal that the LH sends excitatory and inhibitory input onto VTA dopamine (DA) and GABA neurons, and that the GABAergic projection drives feeding-related behavior. Our study overlays information about the type, function and connectivity of LH neurons and identifies a neural circuit that selectively controls compulsive sugar consumption, without preventing feeding necessary for survival, providing a potential target for therapeutic interventions for compulsive-overeating disorder. PMID:25635460

  18. Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size.

    PubMed

    Wang, Liang; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

    2015-12-01

    Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population.

  19. Multisite phosphorylation of spinach leaf sucrose-phosphate synthase

    SciTech Connect

    Huber, J.L.; Huber, S.C. )

    1990-05-01

    Spinach leaf sucrose-phosphate synthase is phosphorylated both in vivo and in vitro on serine residues. Phosphorylation of SPS in vivo yields twelve major phosphopeptides after a tryptic digest and two dimensional mapping. The in vivo labeling of three of these SPS P-peptides is reduced in illuminated leaves where the extracted enzyme is activated relative to that of dark leaves. Two of these inhibitory sites are phosphorylated as well when SPS is inactivated in vitro using ({sup 32}P)ATP. In vivo phosphorylation of two other sites is enhanced during mannose feeding of the leaves (in light or dark) which produces the highest activation state of SPS. Overall, the results confirm that light-dark regulation of SPS activity occurs as a result of regulatory seryl-phosphorylation and involves a balance between phosphorylation of sites which inhibit or stimulate activity. Regulation of the SPS protein kinase that inhibits activity is relatively unaffected by phosphate but inhibited by G1c 6-P (IC{sub 50}{approx}5 mM), which may explain the control of SPS activation state by light-dark signals.

  20. The Spatial Distribution of Sucrose Synthase Isozymes in Barley.

    PubMed Central

    Guerin, J.; Carbonero, P.

    1997-01-01

    The sucrose (Suc) synthase enzyme purified from barley (Hordeum vulgare L.) roots is a homotetramer that is composed of 90-kD type 1 Suc synthase (SS1) subunits. Km values for Suc and UDP were 30 mM and 5 [mu]M, respectively. This enzyme can also utilize ADP at 25% of the UDP rate. Anti-SS1 polyclonal antibodies, which recognized both SS1 and type 2 Suc synthase (SS2) (88-kD) subunits, and antibodies raised against a synthetic peptide, LANGSTDNNFV, which were specific for SS2, were used to study the spatial distribution of these subunits by immunoblot analysis and immunolocalization. Both SS1 and SS2 were abundantly expressed in endosperm, where they polymerize to form the five possible homo- and heterotetramers. Only SS1 homotetramers were detected in young leaves, where they appeared exclusively in phloem cells, and in roots, where expression was associated with cap cells and the vascular bundle. In the seed both SS1 and SS2 were present in endosperm, but only SS1 was apparent in the chalazal region, the nucellar projection, and the vascular bundle. The physiological implications for the difference in expression patterns observed are discussed with respect to the maize (Zea mays L.) model. PMID:12223688

  1. Gradient zone boundary control in salt gradient solar ponds

    DOEpatents

    Hull, John R.

    1984-01-01

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  2. Titanium corrosion in alkaline hydrogen peroxide environments

    NASA Astrophysics Data System (ADS)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  3. Recent Alkaline Lakes: Clues to Understanding the Evolution of Early Planetary Alkaline Oceans and Biogenesis

    NASA Astrophysics Data System (ADS)

    Kempe, S.; Hartmann, J.; Kazmierczak, J.

    2008-09-01

    Abstract New models suggest that terrestrial weathering consumes 0.26GtC/a (72% silicate-, 28% carbonateweathering), equivalent to a loss of one atmospheric C content every 3700a. Rapid weathering leads in volcanic areas to alkaline conditions, illustrated by the crater lake of Niuafo`ou/Tonga and Lake Van/Turkey, the largest soda lake on Earth. Alkaline conditions cause high CaCO3 supersaturation, permineralization of algal mats and growth of stromatolites. Alkaline conditions can nearly depress free [Ca2+] to levels necessary for proteins to function. Therefore early oceans on Earth (and possibly on Mars) should have been alkaline (i.e. "Soda Oceans"). Recent findings of MgSO4 in top soils on Mars may be misleading about the early history of martian oceans.

  4. Proton Gradients and Proton-Dependent Transport Processes in the Chloroplast

    PubMed Central

    Höhner, Ricarda; Aboukila, Ali; Kunz, Hans-Henning; Venema, Kees

    2016-01-01

    Proton gradients are fundamental to chloroplast function. Across thylakoid membranes, the light induced -proton gradient is essential for ATP synthesis. As a result of proton pumping into the thylakoid lumen, an alkaline stromal pH develops, which is required for full activation of pH-dependent Calvin Benson cycle enzymes. This implies that a pH gradient between the cytosol (pH 7) and the stroma (pH 8) is established upon illumination. To maintain this pH gradient chloroplasts actively extrude protons. More than 30 years ago it was already established that these proton fluxes are electrically counterbalanced by Mg2+, K+, or Cl- fluxes, but only recently the first transport systems that regulate the pH gradient were identified. Notably several (Na+,K+)/H+ antiporter systems where identified, that play a role in pH gradient regulation, ion homeostasis, osmoregulation, or coupling of secondary active transport. The established pH gradients are important to drive uptake of essential ions and solutes, but not many transporters involved have been identified to date. In this mini review we summarize the current status in the field and the open questions that need to be addressed in order to understand how pH gradients are maintained, how this is interconnected with other transport processes and what this means for chloroplast function. PMID:26973667

  5. Isolation of Macrophage Early and Late Endosomes by Latex Bead Internalization and Density Gradient Centrifugation.

    PubMed

    Lamberti, Giorgia; de Araújo, Mariana E G; Huber, Lukas A

    2015-12-01

    Immortalized macrophage lines and primary macrophages display the ability to internalize small latex beads through the endocytic pathway. This protocol describes a simple and robust method for separating endocytic organelles from macrophages on a sucrose gradient, taking advantage of the significantly lower density of the organelles containing latex beads compared with other intracellular organelles. The latex beads are retained in the endosomes as they mature; therefore, harvesting cells at different time points after internalization permits the purification of different organelle fractions, particularly early and late endosomes. PMID:26631120

  6. A method for making an alkaline battery electrode plate

    NASA Technical Reports Server (NTRS)

    Chida, K.; Ezaki, T.

    1983-01-01

    A method is described for making an alkaline battery electrode plate where the desired active substances are filled into a nickel foam substrate. In this substrate an electrolytic oxidation reduction occurs in an alkaline solution containing lithium hydroxide.

  7. Factors affecting alkalinity generation by successive alkalinity-producing systems: regression analysis.

    PubMed

    Jage, C R; Zipper, C E; Noble, R

    2001-01-01

    Use of successive alkalinity-producing systems (SAPS) for treatment of acidic mine drainage (AMD) has grown in recent years. However, inconsistent performance has hampered widespread acceptance of this technology. This research was conducted to determine the influence of system design and influent AMD chemistry on net alkalinity generation by SAPS. Monthly observations were obtained from eight SAPS cells in southern West Virginia and southwestern Virginia. Analysis of these data revealed strong, positive correlations between net alkalinity generation and three variables: the natural log of limestone residence time, influent dissolved Fe concentration, and influent non-Mn acidity. A statistical model was constructed to describe SAPS performance. Subsequent analysis of data obtained from five systems in western Pennsylvania (calibration data set) was used to reevaluate the model form, and the statistical model was adjusted using the combined data sets. Limestone residence time exhibited a strong, positive logarithmic correlation with net alkalinity generation, indicating net alkalinity generation occurs most rapidly within the first few hours of AMD-limestone contact and additional residence time yields diminishing gains in treatment. Influent Fe and non-Mn acidity concentrations both show strong positive linear relationships with net alkalinity generation, reflecting the increased solubility of limestone under acidic conditions. These relationships were present in the original and the calibration data sets, separately, and in the statistical model derived from the combined data set. In the combined data set, these three factors accounted for 68% of the variability in SAPS systems performance. PMID:11401248

  8. Physical and Kinetic Evidence for an Association between Sucrose-Phosphate Synthase and Sucrose-Phosphate Phosphatase.

    PubMed Central

    Echeverria, E.; Salvucci, M. E.; Gonzalez, P.; Paris, G.; Salerno, G.

    1997-01-01

    The possible formation of a multienzyme complex between sucrose (Suc)-phosphate synthase (SPS) and Suc-phosphate phosphatase (SPP) was examined by measuring the rates of Suc-6-phosphate (Suc-6-P) synthesis and hydrolysis in mixing experiments with partially purified enzymes from spinach (Spinacia oleracea) and rice (Oryza sativa) leaves. The addition of SPP to SPS stimulated the rate of Suc-6-P synthesis. SPS inhibited the hydrolysis of exogenous Suc-6-P by SPP when added in the absence of its substrate (i.e. UDP-glucose) but stimulated SPP activity when the SPS substrates were present and used to generate Suc-6-P directly in the reaction. Results from isotope-dilution experiments suggest that Suc-6-P was channeled between SPS and SPP. A portion of the SPS activity comigrated with SPP during native polyacrylamide gel electrophoresis, providing physical evidence for an enzyme-enzyme interaction. Taken together, these results strongly suggest that SPS and SPP associate to form a multienzyme complex. PMID:12223802

  9. Sucrose in Cyanobacteria: From a Salt-Response Molecule to Play a Key Role in Nitrogen Fixation

    PubMed Central

    Kolman, María A.; Nishi, Carolina N.; Perez-Cenci, Macarena; Salerno, Graciela L.

    2015-01-01

    In the biosphere, sucrose is mainly synthesized in oxygenic photosynthetic organisms, such as cyanobacteria, green algae and land plants, as part of the carbon dioxide assimilation pathway. Even though its central position in the functional biology of plants is well documented, much less is known about the role of sucrose in cyanobacteria. In those prokaryotes, sucrose accumulation has been associated with salt acclimation, and considered as a compatible solute in low-salt tolerant strains. In the last years, functional characterizations of sucrose metabolizing enzymes, metabolic control analysis, cellular localization of gene expressions, and reverse genetic experiments have revealed that sucrose metabolism is crucial in the diazotrophic growth of heterocystic strains, and besides, that it can be connected to glycogen synthesis. This article briefly summarizes the current state of knowledge of sucrose physiological functions in modern cyanobacteria and how they might have evolved taking into account the phylogenetic analyses of sucrose enzymes. PMID:25569239

  10. Metabolic effects of adding sucrose and aspartame to the diet of subjects with noninsulin-dependent diabetes mellitus.

    PubMed

    Colagiuri, S; Miller, J J; Edwards, R A

    1989-09-01

    This study compared the effects of adding sucrose and aspartame to the usual diet of individuals with well-controlled noninsulin-dependent diabetes mellitus (NIDDM). A double-blind, cross-over design was used with each 6-wk study period. During the sucrose period, 45 g sucrose (9% of total daily energy) was added, 10 g with each main meal and 5 g with each between-meal beverage. An equivalent sweetening quantity of aspartame (162 mg) was ingested during the aspartame period. The addition of sucrose did not have a deleterious effect on glycemic control, lipids, glucose tolerance, or insulin action. No differences were observed between sucrose and aspartame. Sucrose added as an integral part of the diabetic diet does not adversely affect metabolic control in well-controlled NIDDM subjects. Aspartame is an acceptable sugar substitute for diabetic individuals but no specific advantage over sucrose was demonstrated.

  11. Combining Step Gradients and Linear Gradients in Density.

    PubMed

    Kumar, Ashok A; Walz, Jenna A; Gonidec, Mathieu; Mace, Charles R; Whitesides, George M

    2015-06-16

    Combining aqueous multiphase systems (AMPS) and magnetic levitation (MagLev) provides a method to produce hybrid gradients in apparent density. AMPS—solutions of different polymers, salts, or surfactants that spontaneously separate into immiscible but predominantly aqueous phases—offer thermodynamically stable steps in density that can be tuned by the concentration of solutes. MagLev—the levitation of diamagnetic objects in a paramagnetic fluid within a magnetic field gradient—can be arranged to provide a near-linear gradient in effective density where the height of a levitating object above the surface of the magnet corresponds to its density; the strength of the gradient in effective density can be tuned by the choice of paramagnetic salt and its concentrations and by the strength and gradient in the magnetic field. Including paramagnetic salts (e.g., MnSO4 or MnCl2) in AMPS, and placing them in a magnetic field gradient, enables their use as media for MagLev. The potential to create large steps in density with AMPS allows separations of objects across a range of densities. The gradients produced by MagLev provide resolution over a continuous range of densities. By combining these approaches, mixtures of objects with large differences in density can be separated and analyzed simultaneously. Using MagLev to add an effective gradient in density also enables tuning the range of densities captured at an interface of an AMPS by simply changing the position of the container in the magnetic field. Further, by creating AMPS in which phases have different concentrations of paramagnetic ions, the phases can provide different resolutions in density. These results suggest that combining steps in density with gradients in density can enable new classes of separations based on density. PMID:25978093

  12. Alkaline polymer electrolyte membranes for fuel cell applications.

    PubMed

    Wang, Yan-Jie; Qiao, Jinli; Baker, Ryan; Zhang, Jiujun

    2013-07-01

    In this review, we examine the most recent progress and research trends in the area of alkaline polymer electrolyte membrane (PEM) development in terms of material selection, synthesis, characterization, and theoretical approach, as well as their fabrication into alkaline PEM-based membrane electrode assemblies (MEAs) and the corresponding performance/durability in alkaline polymer electrolyte membrane fuel cells (PEMFCs). Respective advantages and challenges are also reviewed. To overcome challenges hindering alkaline PEM technology advancement and commercialization, several research directions are then proposed.

  13. High field gradient particle accelerator

    DOEpatents

    Nation, J.A.; Greenwald, S.

    1989-05-30

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  14. High field gradient particle accelerator

    DOEpatents

    Nation, John A.; Greenwald, Shlomo

    1989-01-01

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  15. Identification and Characterization of the Sucrose Synthase 2 Gene (Sus2) in Durum Wheat

    PubMed Central

    Volpicella, Mariateresa; Fanizza, Immacolata; Leoni, Claudia; Gadaleta, Agata; Nigro, Domenica; Gattulli, Bruno; Mangini, Giacomo; Blanco, Antonio; Ceci, Luigi R.

    2016-01-01

    Sucrose transport is the central system for the allocation of carbon resources in vascular plants. Sucrose synthase (SUS), which reversibly catalyzes sucrose synthesis and cleavage, represents a key enzyme in the control of the flow of carbon into starch biosynthesis. In the present study the genomic identification and characterization of the Sus2-2A and Sus2-2B genes coding for SUS in durum wheat (cultivars Ciccio and Svevo) is reported. The genes were analyzed for their expression in different tissues and at different seed maturation stages, in four tetraploid wheat genotypes (Svevo, Ciccio, Primadur, and 5-BIL42). The activity of the encoded proteins was evaluated by specific activity assays on endosperm extracts and their structure established by modeling approaches. The combined results of sucrose synthase 2 expression and activity levels were then considered in the light of their possible involvement in starch yield. PMID:27014292

  16. Dextran synthesized by Leuconostoc mesenteroides BD1710 in tomato juice supplemented with sucrose.

    PubMed

    Han, Jin; Hang, Feng; Guo, Benheng; Liu, Zhenmin; You, Chunpin; Wu, Zhengjun

    2014-11-01

    The characteristics of the growth of Leuconostoc mesenteroides BD1710 and the synthesis of dextran in tomato juice supplemented with 15% sucrose were assayed. L. mesenteroides BD1710 could synthesize approximately 32 g L(-1) dextran in the tomato-juice-sucrose medium when cultured at 28 °C for 48 h, which was on the same level as the dextran yield in a chemically defined medium. The viscosity of the cultured tomato-juice-sucrose medium with various dextran contents was also measured. The results of the monosaccharide composition, molecular-weight distribution, Fourier transform infrared spectra (FTIR) and nuclear magnetic resonance spectra (NMR) showed that the polysaccharide synthesized by L. mesenteroides BD1710 in the tomato-juice-sucrose medium was dextran with a peak molecular weight of 6.35 × 10(5)Da, a linear backbone composed of consecutive α-(1 → 6)-linked d-glucopyranosyl units and approximately 6% α-(1 → 3) branches.

  17. Synthesis of oligo- and polysaccharides by Lactobacillus reuteri 121 reuteransucrase at high concentrations of sucrose.

    PubMed

    Meng, Xiangfeng; Dobruchowska, Justyna M; Gerwig, Gerrit J; Kamerling, Johannis P; Dijkhuizen, Lubbert

    2015-09-23

    GTFA, a glucansucrase enzyme of the probiotic bacterium Lactobacillus reuteri 121, is capable of synthesizing an α-glucan polysaccharide with (1 → 4) and (1 → 6) linkages from sucrose. With respect to its biosynthesis, the present study has shown that the ratio of oligosaccharide versus polysaccharide synthesized was directly proportional to the concentration of sucrose. It appears that the size distribution of products is kinetically controlled, but the linkage distribution in the polysaccharide material is not changed. At high sucrose concentrations the sucrose isomers leucrose and trehalulose were synthesized, using the accumulated fructose as acceptor, together with 4'- and 6'-α-D-glucosyl-leucrose and 6'-α-D-glucosyl-trehalulose. The finding of an additional branched hexasaccharide demonstrates that the enzyme is able to introduce branch-points already in relatively short oligosaccharides.

  18. The interaction of temperature and sucrose concentration on foraging preferences in bumblebees

    NASA Astrophysics Data System (ADS)

    Whitney, Heather M.; Dyer, Adrian; Chittka, Lars; Rands, Sean A.; Glover, Beverley J.

    2008-09-01

    Several authors have found that flowers that are warmer than their surrounding environment have an advantage in attracting pollinators. Bumblebees will forage preferentially on warmer flowers, even if equal nutritional reward is available in cooler flowers. This raises the question of whether warmth and sucrose concentration are processed independently by bees, or whether sweetness detectors respond to higher sugar concentration as well as higher temperature. We find that bumblebees can use lower temperature as a cue to higher sucrose reward, showing that bees appear to process the two parameters strictly independently. Moreover, we demonstrate that sucrose concentration takes precedence over warmth, so that when there is a difference in sucrose concentration, bees will typically choose the sweeter feeder, even if the less sweet feeder is several degrees warmer.

  19. Possible mechanism of mannose inhibition of sucrose-supported growth in N2-fixing Azotobacter vinelandii.

    PubMed Central

    Wong, T Y

    1990-01-01

    When mannose was added to a sucrose-supported culture of Azotobacter vinelandii under N2-fixing conditions, cell growth was inhibited. The degree of inhibition was proportional to the amount of mannose and to the aeration rate (T.-Y. Wong, Appl. Environ. Microbiol. 54:473-475, 1988). In this report, we demonstrate that once inside the cell, mannose was phosphorylated to mannose 6-phosphate. It was then isomerized to fructose 6-phosphate and to glucose 6-phosphate. Mannose inhibited sucrose uptake noncompetitively. The decrease in sucrose uptake after mannose addition coincided with a lower rate of respiration and a decrease in nitrogenase activity. The decrease in sucrose uptake and in the ATP pool may decrease the electron flow and reduce protection of the nitrogenase from O2. Cells became very sensitive to O2, and therefore, cell growth was inhibited under high aeration conditions. PMID:2310189

  20. The interaction of temperature and sucrose concentration on foraging preferences in bumblebees.

    PubMed

    Whitney, Heather M; Dyer, Adrian; Chittka, Lars; Rands, Sean A; Glover, Beverley J

    2008-09-01

    Several authors have found that flowers that are warmer than their surrounding environment have an advantage in attracting pollinators. Bumblebees will forage preferentially on warmer flowers, even if equal nutritional reward is available in cooler flowers. This raises the question of whether warmth and sucrose concentration are processed independently by bees, or whether sweetness detectors respond to higher sugar concentration as well as higher temperature. We find that bumblebees can use lower temperature as a cue to higher sucrose reward, showing that bees appear to process the two parameters strictly independently. Moreover, we demonstrate that sucrose concentration takes precedence over warmth, so that when there is a difference in sucrose concentration, bees will typically choose the sweeter feeder, even if the less sweet feeder is several degrees warmer.

  1. Microplate assay for rapid determination of sucrose, glucose, fructose and raffinose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current methods for the quantification of carbohydrates in sugarbeet roots have limitations. Polarimetry and refractometry measure only sucrose content and are inaccurate with deteriorated roots. High performance liquid chromatography (HPLC) and gas chromatography (GC) quantify all simple carbohy...

  2. Diverse Exopolysaccharide Producing Bacteria Isolated from Milled Sugarcane: Implications for Cane Spoilage and Sucrose Yield.

    PubMed

    Hector, Stanton; Willard, Kyle; Bauer, Rolene; Mulako, Inonge; Slabbert, Etienne; Kossmann, Jens; George, Gavin M

    2015-01-01

    Bacterial deterioration of sugarcane during harvesting and processing is correlated with significant loss of sucrose yield and the accumulation of bacterial polysaccharides. Dextran, a homoglucan produced by Leuconostoc mesenteroides, has been cited as the primary polysaccharide associated with sugarcane deterioration. A culture-based approach was used to isolate extracellular polysaccharide (EPS) producing bacterial strains from milled sugarcane stalks. Ribosomal RNA sequencing analysis grouped 25 isolates into 4 genera. This study identified 2 bacterial genera not previously associated with EPS production or sucrose degradation. All isolates produced polysaccharide when grown in the presence of sucrose. Monosaccharide analysis of purified polymers by Gas Chromatography revealed 17 EPSs consisting solely of glucose (homoglucans), while the remainder contained traces of mannose or fructose. Dextranase treatment of polysaccharides yielded full digestion profiles for only 11 extracts. Incomplete hydrolysis profiles of the remaining polysaccharides suggest the release of longer oligosaccharides which may interfere with sucrose crystal formation. PMID:26710215

  3. Modeling Sucrose Hydrolysis in Dilute Sulfuric Acid Solutions at Pretreatment Conditions for Lignocellulosic Biomass

    SciTech Connect

    Bower, S.; Wickramasinghe, R.; Nagle, N. J.; Schell, D. J.

    2008-01-01

    Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25 g/l sucrose with 0.1-2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160-200 C for 3-12 min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products.

  4. Diverse Exopolysaccharide Producing Bacteria Isolated from Milled Sugarcane: Implications for Cane Spoilage and Sucrose Yield

    PubMed Central

    Bauer, Rolene; Mulako, Inonge; Slabbert, Etienne; Kossmann, Jens; George, Gavin M

    2015-01-01

    Bacterial deterioration of sugarcane during harvesting and processing is correlated with significant loss of sucrose yield and the accumulation of bacterial polysaccharides. Dextran, a homoglucan produced by Leuconostoc mesenteroides, has been cited as the primary polysaccharide associated with sugarcane deterioration. A culture-based approach was used to isolate extracellular polysaccharide (EPS) producing bacterial strains from milled sugarcane stalks. Ribosomal RNA sequencing analysis grouped 25 isolates into 4 genera. This study identified 2 bacterial genera not previously associated with EPS production or sucrose degradation. All isolates produced polysaccharide when grown in the presence of sucrose. Monosaccharide analysis of purified polymers by Gas Chromatography revealed 17 EPSs consisting solely of glucose (homoglucans), while the remainder contained traces of mannose or fructose. Dextranase treatment of polysaccharides yielded full digestion profiles for only 11 extracts. Incomplete hydrolysis profiles of the remaining polysaccharides suggest the release of longer oligosaccharides which may interfere with sucrose crystal formation. PMID:26710215

  5. Postsecretory hydrolysis of nectar sucrose and specialization in ant/plant mutualism.

    PubMed

    Heil, M; Rattke, J; Boland, W

    2005-04-22

    Obligate Acacia ant plants house mutualistic ants as a defense mechanism and provide them with extrafloral nectar (EFN). Ant/plant mutualisms are widespread, but little is known about the biochemical basis of their species specificity. Despite its importance in these and other plant/animal interactions, little attention has been paid to the control of the chemical composition of nectar. We found high invertase (sucrose-cleaving) activity in Acacia EFN, which thus contained no sucrose. Sucrose, a disaccharide common in other EFNs, usually attracts nonsymbiotic ants. The EFN of the ant acacias was therefore unattractive to such ants. The Pseudomyrmex ants that are specialized to live on Acacia had almost no invertase activity in their digestive tracts and preferred sucrose-free EFN. Our results demonstrate postsecretory regulation of the carbohydrate composition of nectar.

  6. The effects of fruiting positions on cellulose synthesis and sucrose metabolism during cotton (Gossypium hirsutum L.) fiber development.

    PubMed

    Ma, Yina; Wang, Youhua; Liu, Jingran; Lv, Fengjuan; Chen, Ji; Zhou, Zhiguo

    2014-01-01

    Cotton (Gossypium hirsutum L.) boll positions on a fruiting branch vary in their contribution to yield and fiber quality. Fiber properties are dependent on deposition of cellulose in the fiber cell wall, but information about the enzymatic differences in sucrose metabolism between these fruiting positions is lacking. Therefore, two cotton cultivars with different sensitivities to low temperature were tested in 2010 and 2011 to quantify the effect of fruit positions (FPs) on fiber quality in relation to sucrose content, enzymatic activities and sucrose metabolism. The indices including sucrose content, sucrose transformation rate, cellulose content, and the activities of the key enzymes, sucrose phosphate synthase (SPS), acid invertase (AI) and sucrose synthase (SuSy) which inhibit cellulose synthesis and eventually affect fiber quality traits in cotton fiber, were determined. Results showed that as compared with those of FP1, cellulose content, sucrose content, and sucrose transformation rate of FP3 were all decreased, and the variations of cellulose content and sucrose transformation rate caused by FPs in Sumian 15 were larger than those in Kemian 1. Under FP effect, activities of SPS and AI in sucrose regulation were decreased, while SuSy activity in sucrose degradation was increased. The changes in activities of SuSy and SPS in response to FP effect displayed different and large change ranges between the two cultivars. These results indicate that restrained cellulose synthesis and sucrose metabolism in distal FPs are mainly attributed to the changes in the activities of these enzymes. The difference in fiber quality, cellulose synthesis and sucrose metabolism in response to FPs in fiber cells for the two cotton cultivars was mainly determined by the activities of both SuSy and SPS.

  7. Dosakaya Juice Assuages Development of Sucrose Induced Impaired Glucose Tolerance and Imbalance in Antioxidant Defense

    PubMed Central

    Kumar, Dommati Anand; Sweeya, Pisupati S. R.; Shukla, Srishti; Anusha, Sanga Venkata; Akshara, Dasari; Madhusudana, Kuncha; Tiwari, Ashok Kumar

    2015-01-01

    Objective: The objective was to explore the effect of Dosakaya (DK) (Cucumis melo var. chito) juice on sucrose induced dysglycemia and disturbances in antioxidant defense in rats. Materials and Methods: Rats were preconditioned with DK juice before administration of sucrose beverage continuously for 1-month. Blood glucose tolerance test and glutathione (GSH) homeostasis pathways in kidney were analyzed in different group of animals at the end of the study. Results: DK juice diffused (P < 0.001) hypertriglyceridemia inducing effect of sucrose and arrested sucrose induced weight gain. It improved glucose tolerance ability by significantly reducing (P < 0.05) first-hour glycemic excursion and decreasing 2 h glycemic load (P < 0.05) following oral glucose tolerance test in sucrose fed animals. Furthermore, disturbances in antioxidant defense mechanisms in terms of GSH homeostasis in kidney were restored due to juice feeding. DK juice administration checked reduction in GSH-S-transferase and glyoxalase-I activity, thus, significantly mitigated lipid peroxidation (P < 0.05), and formation of advanced glycation end-products (P < 0.001) in kidney and serum (P < 0.01). Quantitative analysis of juice found it a rich source of protein and polyphenols. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed the presence of multiple protein bands in whole fruit juice. Therefore, SDS-PAGE protein fingerprint of DK juice may serve as a quality control tool for standardization of juice. Conclusion: The whole fruit juice of DK may become cost-effective, affordable health beverage in extenuating ill-health effects of sugar consumption. This is the first report identifying DK juice in preventing development dysglycemia, dyslipidemia, and oxidative stress induced due to chronic sucrose feeding in rats. SUMMARY Chronic sucrose consumption induced development of dysglycemia and also impaired antioxidant defense mechanism in rats. The oral administration of

  8. Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida.

    PubMed

    Barbier, François; Péron, Thomas; Lecerf, Marion; Perez-Garcia, Maria-Dolores; Barrière, Quentin; Rolčík, Jakub; Boutet-Mercey, Stéphanie; Citerne, Sylvie; Lemoine, Remi; Porcheron, Benoît; Roman, Hanaé; Leduc, Nathalie; Le Gourrierec, José; Bertheloot, Jessica; Sakr, Soulaiman

    2015-05-01

    Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone-transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar.

  9. Feeding behavior and social interactions of the Argentine ant Linepithema humile change with sucrose concentration.

    PubMed

    Sola, F J; Josens, R

    2016-08-01

    Liquid sugar baits are well accepted by the Argentine ant Linepithema humile and are suitable for the chemical control of this invasive species. We evaluated how sugar concentrations affect the foraging behavior of L. humile individuals. We quantified feeding variables for individual foragers (ingested load, feeding time and solution intake rate) when feeding on sucrose solutions of different concentrations, as well as post-feeding interactions with nestmates. Solutions of intermediate sucrose concentrations (10-30%) were the most consumed and had the highest intake rates, whereas solutions of high sucrose concentrations (60 and 70%) resulted in extended feeding times, low intake rates and ants having smaller crop loads. In terms of post-feeding interactions, individuals fed solutions of intermediate sucrose concentrations (20%) had the highest probability of conducting trophallaxis and the smallest latency to drop exposure (i.e. lowest time delay). Trophallaxis duration increased with increasing sucrose concentrations. Behavioral motor displays, including contacts with head jerking and walking with a gaster waggle, were lowest for individuals that ingested the more dilute sucrose solution (5%). These behaviors have been previously suggested to act as a communication channel for the activation and/or recruitment of nestmates. We show here that sucrose concentration affects feeding dynamics and modulates decision making related to individual behavior and social interactions of foragers. Our results indicate that intermediate sucrose concentrations (ca. 20%), appear to be most appropriate for toxic baits because they promote rapid foraging cycles, a high crop load per individual, and a high degree of stimulation for recruitment.

  10. Feeding behavior and social interactions of the Argentine ant Linepithema humile change with sucrose concentration.

    PubMed

    Sola, F J; Josens, R

    2016-08-01

    Liquid sugar baits are well accepted by the Argentine ant Linepithema humile and are suitable for the chemical control of this invasive species. We evaluated how sugar concentrations affect the foraging behavior of L. humile individuals. We quantified feeding variables for individual foragers (ingested load, feeding time and solution intake rate) when feeding on sucrose solutions of different concentrations, as well as post-feeding interactions with nestmates. Solutions of intermediate sucrose concentrations (10-30%) were the most consumed and had the highest intake rates, whereas solutions of high sucrose concentrations (60 and 70%) resulted in extended feeding times, low intake rates and ants having smaller crop loads. In terms of post-feeding interactions, individuals fed solutions of intermediate sucrose concentrations (20%) had the highest probability of conducting trophallaxis and the smallest latency to drop exposure (i.e. lowest time delay). Trophallaxis duration increased with increasing sucrose concentrations. Behavioral motor displays, including contacts with head jerking and walking with a gaster waggle, were lowest for individuals that ingested the more dilute sucrose solution (5%). These behaviors have been previously suggested to act as a communication channel for the activation and/or recruitment of nestmates. We show here that sucrose concentration affects feeding dynamics and modulates decision making related to individual behavior and social interactions of foragers. Our results indicate that intermediate sucrose concentrations (ca. 20%), appear to be most appropriate for toxic baits because they promote rapid foraging cycles, a high crop load per individual, and a high degree of stimulation for recruitment. PMID:27063551

  11. Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida.

    PubMed

    Barbier, François; Péron, Thomas; Lecerf, Marion; Perez-Garcia, Maria-Dolores; Barrière, Quentin; Rolčík, Jakub; Boutet-Mercey, Stéphanie; Citerne, Sylvie; Lemoine, Remi; Porcheron, Benoît; Roman, Hanaé; Leduc, Nathalie; Le Gourrierec, José; Bertheloot, Jessica; Sakr, Soulaiman

    2015-05-01

    Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone-transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar. PMID:25873679

  12. Toxicity and repellency of borate-sucrose water baits to Argentine ants (Hymenoptera: Formicidae).

    PubMed

    Klotz, J H; Greenberg, L; Amrhein, C; Rust, M K

    2000-08-01

    The oral toxicity of boron compounds to the Argentine ant, Linepithema humile (Mayr), was evaluated in laboratory tests. The ants were provided 25% sucrose water containing 0.5 and 1% boric acid, disodium octaborate tetrahydrate, and borax. Lethal times of these solutions were a function of the concentration of boron. In field tests, the ants showed no discrimination between disodium octaborate tetrahydrate and boric acid. There was a significant reduction in consumption of sucrose water with > 1% boric acid.

  13. The sulphate-reduction alkalinity pump tested

    NASA Astrophysics Data System (ADS)

    Meister, Patrick; Petrishcheva, Elena

    2016-04-01

    Carbonate precipitation has been suggested to be induced by alkalinity increase during sulphate reduction under anoxic conditions. This mechanism may explain the formation of carbonate deposits in shallow marine environments, either within a redox stratified sediment inhabited by phototrophic microbial mats or in shallow water within the photic zone where sulphidic water is upwelling onto the shelf. The alkalinity pump may work as long as the sulphide is not reoxidized to sulphate, a process that would acidify the surrounding. The alkalinity effect of sulphate reduction was recently tested by Aloisi (2008) for microbial mats using a model approach. He found that sulphate reduction does not significantly increase or even decrease carbonate saturation and is unlikely to have played a significant role through Earth history. The model considers many environmental factors, including the effect of carbonate precipitation itself on the carbonate equilbrium and on the alkalinity. We used a modified version of Aloisi's (2008) model to simulate the saturation states of aragonite, calcite and dolomite without the effects of carbonate precipitation. This is necessary to evaluate the effect of microbial metabolisms exclusively on carbonate saturation, since carbonate precipitation is only the consequence, but not the cause of oversaturation. First results show that the saturation state is increased in the zone of phototrophic CO2 uptake. In contrast, the saturation state is strongly decreased in the zone where dissolved oxygen overlaps with dissolved sulphide. Aerobic sulphide oxidation consumes most of the HS- and dissipates most of the alkalinity produced in the sulphate reduction zone below. Hence, our results are consistent with the findings of Aloisi (2008), and they even more clearly show that sulphate reduction does not induce carbonate precipitation nor contributes to carbonate precipitation in combination with phototrophic CO2 uptake. The alkalinity effect of sulphate

  14. Enhancement of sucrose sweetness with soluble starch in humans.

    PubMed

    Kanemaru, Norikazu; Harada, Shuitsu; Kasahara, Yasuo

    2002-01-01

    The effect of soluble starch (acid-modified starch) on taste intensity was investigated in human subjects. Different concentrations of sucrose (Suc), six sweeteners, NaCl, quinine-HCl (QHCl) and citric acid (Cit) were dissolved in either distilled water (DW; standard) or starch solution (test solution). The solutions were presented to naive subjects and each subject was requested to taste and compare the sweetness intensity between the standard and test solutions based on a scale ranging from +3 (enhanced) to -3 (inhibited). A greater sweetness intensity occurred with Suc at different concentration (0.1-1.0 M) dissolved in soluble starch (0.125% to 4.0%) than with Suc in DW. Similarly, five other different products of soluble starch at 0.25 and 4.0% resulted in enhancement of sweetness for 0.3 and 1.0 M Suc. With the sole exception of the taste of 0.3 M Suc, sweet enhancement did not occur with 0.43 M fructose, 0.82 M glucose, 0.82 M sorbitol, 0.0037 M aspartame, 0.0042 M saccharin-Na or 0.016 M cyclamate. Neither the saltiness of NaCl (0.01-0.3 M), the bitterness of QHCl (0.00003-0.001 M) nor the sourness of Cit (0.0003-0.01 M) were affected by the soluble starch. These results suggest that the taste enhancing effects of soluble starch on Suc sweetness might depend not only on the taste transduction mechanism, but also on the molecular interaction between Suc and soluble starch.

  15. Sucrose-predictive cues evoke greater phasic dopamine release than saccharin-predictive cues

    PubMed Central

    McCutcheon, James E.; Beeler, Jeff A.; Roitman, Mitchell F.

    2012-01-01

    Cues that have been paired with food evoke dopamine in nucleus accumbens (NAc) and drive approach behavior. This cue-evoked dopamine signaling could contribute to overconsumption of food. One manner in which individuals try to restrict caloric intake is through the consumption of foods containing artificial (non-nutritive) sweeteners. We were interested in whether cues paired with a non-nutritive sweetener (saccharin) would evoke similar dopamine release as cues paired with a nutritive sweetener (sucrose). We trained food-restricted rats to associate distinct cues with sucrose or saccharin pellets. In the first group of rats, training sessions with each pellet took place on different days, maximizing the opportunity for rats to detect nutritional differences. After training, voltammetry recordings in NAc core revealed that sucrose cues evoked greater phasic dopamine release than saccharin cues. In a second group of rats, on each training day, sucrose and saccharin pellets were presented in pseudorandom order within the same session, to mask nutritional differences. In this condition, the difference in dopamine between sucrose and saccharin cues was attenuated, but not abolished. These results suggest that sucrose-paired cues will more powerfully motivate behavior than saccharin-paired cues. The differing responses to each cue seem to be driven by overall preference with both the nutritional value that the pellets predict as well as other factors, such as taste, contributing. PMID:22170625

  16. Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9.

    PubMed

    Lin, I Winnie; Sosso, Davide; Chen, Li-Qing; Gase, Klaus; Kim, Sang-Gyu; Kessler, Danny; Klinkenberg, Peter M; Gorder, Molly K; Hou, Bi-Huei; Qu, Xiao-Qing; Carter, Clay J; Baldwin, Ian T; Frommer, Wolf B

    2014-04-24

    Angiosperms developed floral nectaries that reward pollinating insects. Although nectar function and composition have been characterized, the mechanism of nectar secretion has remained unclear. Here we identify SWEET9 as a nectary-specific sugar transporter in three eudicot species: Arabidopsis thaliana, Brassica rapa (extrastaminal nectaries) and Nicotiana attenuata (gynoecial nectaries). We show that SWEET9 is essential for nectar production and can function as an efflux transporter. We also show that sucrose phosphate synthase genes, encoding key enzymes for sucrose biosynthesis, are highly expressed in nectaries and that their expression is also essential for nectar secretion. Together these data are consistent with a model in which sucrose is synthesized in the nectary parenchyma and subsequently secreted into the extracellular space via SWEET9, where sucrose is hydrolysed by an apoplasmic invertase to produce a mixture of sucrose, glucose and fructose. The recruitment of SWEET9 for sucrose export may have been a key innovation, and could have coincided with the evolution of core eudicots and contributed to the evolution of nectar secretion to reward pollinators.

  17. Production of L-ornithine from sucrose and molasses by recombinant Corynebacterium glutamicum.

    PubMed

    Zhang, Yuan-Yuan; Bu, Yi-Fan; Liu, Jian-Zhong

    2015-09-01

    Sucrose and molasses are attractive raw materials for industrial fermentation. Although Corynebacterium glutamicum shows sucrose-utilizing activity, sucrose or molasses is only a fraction of carbon source used in the fermentation medium in most works. An engineered C. glutamicum strain was constructed for producing L-ornithine with sucrose or molasses as a sole carbon source by transferring Mannheimia succiniciproducens β-fructofuranosidase gene (sacC). The engineered strain, C. glutamicum ΔAPE6937R42 (pEC-sacC), produced 22.0 g/L of L-ornithine with sucrose as the sole carbon source, which is on par with that obtained by the parent strain C. glutamicum ΔAPE6937R42 with glucose as the sole carbon. The resulting strain C. glutamicum ΔAPE6937R42 (pEC-sacC) produced 27.0 g/L of L-ornithine with molasses as the sole carbon source, which is higher than that obtained by the parent strain C. glutamicum ΔAPE6937R42 with glucose as the sole carbon. This strategy can be applied for developing sucrose- or molasses-utilizing industrial strains.

  18. Coplanar waveguides loaded with a split ring resonator-based microwave sensor for aqueous sucrose solutions

    NASA Astrophysics Data System (ADS)

    Harnsoongnoen, Supakorn; Wanthong, Anuwat

    2016-01-01

    In this study, a coplanar waveguide (CPW) loaded with a split ring resonator (SRR) based microwave sensor was developed for the detection of aqueous sucrose solutions. The fabrication and testing enabled the identification of the sucrose concentration. The CPW loaded with a SRR structure design was produced using electromagnetic models to improve its sensitivity by increasing the magnitude of transmission coefficient (S 21). The resonance behavior, based on S 21 characteristics of the microwave sensor, was analyzed in the range from 2-3 GHz with air and deionized water containing different sucrose concentrations in the range from 0-1 g ml-1. The experimental results showed that the proposed system has great potential to determine the sucrose concentration. It was shown that the proposed sensor has a high dynamic range and linearity for sucrose concentration sensing. The feature characteristic based on the CPW loaded with SRR sensing was excellent as defined by a T-circuit model as an inductor, capacitor, and resistor. It also provides an opportunity for the development of a low-cost sucrose meter system as an electronic tongue.

  19. Chronic pramipexole treatment increases tolerance for sucrose in normal and ventral tegmental lesioned rats

    PubMed Central

    Dardou, David; Chassain, Carine; Durif, Franck

    2015-01-01

    The loss of dopamine neurons observed in Parkinson's disease (PD) elicits severe motor control deficits which are reduced by the use of dopamine agonists. However, recent works have indicated that D3-preferential agonists such as pramipexole can induce impulse control disorders (ICDs) such as food craving or compulsive eating. In the present study, we performed an intermittent daily feeding experiment to assess the effect of chronic treatment by pramipexole and VTA bilateral lesion on tolerance for sucrose solution. The impact of such chronic treatment on spontaneous locomotion and spatial memory was also examined. Changes in sucrose tolerance could indicate the potential development of a change in food compulsion or addiction related to the action of pramipexole. Neither the bilateral lesion of the VTA nor chronic treatment with pramipexole altered the spontaneous locomotion or spatial memory in rats. Rats without pramipexole treatment quickly developed a stable intake of sucrose solution in the 12 h access phase. On the contrary, when under daily pramipexole treatment, rats developed a stronger and ongoing escalation of their sucrose solution intakes. In addition, we noted that the change in sucrose consumption was sustained by an increase of the expression of the Dopamine D3 receptor in the core and the shell regions of the nucleus accumbens. The present results may suggest that long-term stimulation of the Dopamine D3 receptor in animals induces a strong increase in sucrose consumption, indicating an effect of this receptor on certain pathological aspects of food eating. PMID:25610366

  20. Direct selection of cloned DNA in Bacillus subtilis based on sucrose-induced lethality.

    PubMed Central

    Bramucci, M G; Nagarajan, V

    1996-01-01

    Expression of the Bacillus subtilis or Bacillus amyloliquefaciens sacB gene in the presence of sucrose is lethal for a variety of bacteria. Sucrose-induced lethality can be used to select for inactivation of sacB by insertion of heterologous DNA in sensitive bacteria. This procedure has not been applicable to B. subtilis heretofore because expression of wild-type sacB is not detrimental to B. subtilis. The W29 mutation in the B. amyloliquefaciens sacB gene interferes with processing of the levansucrase signal peptide. The W29 mutation does not affect growth of B. subtilis in media lacking sucrose. However, this mutation inhibited growth of B. subtilis in media containing sucrose. Inactivation of the fructose polymerase activity encoded by sacB indicated that levan production was essential for sucrose-induced lethality. As a result, it was possible to select for cloned DNA in B. subtilis by insertional inactivation of the mutant sacB gene located on a multicopy plasmid vector in medium containing sucrose. PMID:8899981

  1. Expression of peach sucrose transporters in heterologous systems points out their different physiological role.

    PubMed

    Zanon, Laura; Falchi, Rachele; Hackel, Aleksandra; Kühn, Christina; Vizzotto, Giannina

    2015-09-01

    Sucrose is the major phloem-translocated component in a number of economically important plant species. The comprehension of the mechanisms involved in sucrose transport in peach fruit appears particularly relevant, since the accumulation of this sugar, during ripening, is crucial for the growth and quality of the fruit. Here, we report the functional characterisation and subcellular localisation of three sucrose transporters (PpSUT1, PpSUT2, PpSUT4) in peach, and we formulate novel hypotheses about their role in accumulation of sugar. We provide evidence, about the capability of both PpSUT1 and PpSUT4, expressed in mutant yeast strains to transport sucrose. The functionality of PpSUT1 at the plasma membrane, and of PpSUT4 at the tonoplast, has been demonstrated. On the other hand, the functionality of PpSUT2 was not confirmed: this protein is unable to complement two sucrose uptake-deficient mutant yeast strains. Our results corroborate the hypotheses that PpSUT1 partakes in phloem loading in leaves, and PpSUT4 sustains cell metabolism by regulating sucrose efflux from the vacuole.

  2. Sucrose-predictive cues evoke greater phasic dopamine release than saccharin-predictive cues.

    PubMed

    McCutcheon, James E; Beeler, Jeff A; Roitman, Mitchell F

    2012-04-01

    Cues that have been paired with food evoke dopamine in nucleus accumbens (NAc) and drive approach behavior. This cue-evoked dopamine signaling could contribute to overconsumption of food. One manner in which individuals try to restrict caloric intake is through the consumption of foods containing artificial (non-nutritive) sweeteners. We were interested in whether cues paired with a non-nutritive sweetener (saccharin) would evoke similar dopamine release as cues paired with a nutritive sweetener (sucrose). We trained food-restricted rats to associate distinct cues with sucrose or saccharin pellets. In the first group of rats, training sessions with each pellet took place on different days, maximizing the opportunity for rats to detect nutritional differences. After training, voltammetry recordings in NAc core revealed that sucrose cues evoked greater phasic dopamine release than saccharin cues. In a second group of rats, on each training day, sucrose and saccharin pellets were presented in pseudorandom order within the same session, to mask nutritional differences. In this condition, the difference in dopamine between sucrose and saccharin cues was attenuated, but not abolished. These results suggest that sucrose-paired cues will more powerfully motivate behavior than saccharin-paired cues. The differing responses to each cue seem to be driven by overall preference with both the nutritional value that the pellets predict as well as other factors, such as taste, contributing.

  3. [Properties of sucrose phosphorylase from recombinant Escherichia coli and enzymatic synthesis of alpha-arbutin].

    PubMed

    Wan, Yuejia; Ma, Jiangfeng; Xu, Rong; He, Aiyong; Jiang, Min; Chen, Kequan; Jiang, Yin

    2012-12-01

    Sucrose phosphorylase (EC 2.4.1.7, Sucrose phosphorylase, SPase) can be produced by recombinant strain Escherichia coli Rosetta(DE3)/Pet-SPase. Crude enzyme was obtained from the cells by the high pressure disruption and centrifugation. Sucrose phosphorylase was purified by Ni-NTA affinity column chromatography and desalted by ultrafiltration. The specific enzyme activity was 1.1-fold higher than that of the crude enzyme, and recovery rate was 82.7%. The purified recombinant SPase had a band of 59 kDa on SDS-PAGE. Thermostability of the enzyme was shown at temperatures up to 37 degrees C, and pH stability between pH 6.0 and 6.7. The optimum temperature and pH were 37 degrees C and 6.7, respectively. The K(m) of SPase for sucrose was 7.3 mmol/L, and Vmax was 0.2 micromol/(min x mg). Besides, alpha-arbutin was synthesized from sucrose and hydroquinone by transglucosylation with recombinant SPase. The optimal conditions for synthesis of alpha-arbutin were 200 U/mL of recombinant SPase, 20% of sucrose, and 1.6% hydroquinone at pH 6-6.5 and 25 degrees C for 21 h. Under these conditions, alpha-arbutin was obtained with a 78.3% molar yield with respect to hydroquinone, and the concentration of alpha-arbutin was about 31 g/L.

  4. Chronic pramipexole treatment increases tolerance for sucrose in normal and ventral tegmental lesioned rats.

    PubMed

    Dardou, David; Chassain, Carine; Durif, Franck

    2014-01-01

    The loss of dopamine neurons observed in Parkinson's disease (PD) elicits severe motor control deficits which are reduced by the use of dopamine agonists. However, recent works have indicated that D3-preferential agonists such as pramipexole can induce impulse control disorders (ICDs) such as food craving or compulsive eating. In the present study, we performed an intermittent daily feeding experiment to assess the effect of chronic treatment by pramipexole and VTA bilateral lesion on tolerance for sucrose solution. The impact of such chronic treatment on spontaneous locomotion and spatial memory was also examined. Changes in sucrose tolerance could indicate the potential development of a change in food compulsion or addiction related to the action of pramipexole. Neither the bilateral lesion of the VTA nor chronic treatment with pramipexole altered the spontaneous locomotion or spatial memory in rats. Rats without pramipexole treatment quickly developed a stable intake of sucrose solution in the 12 h access phase. On the contrary, when under daily pramipexole treatment, rats developed a stronger and ongoing escalation of their sucrose solution intakes. In addition, we noted that the change in sucrose consumption was sustained by an increase of the expression of the Dopamine D3 receptor in the core and the shell regions of the nucleus accumbens. The present results may suggest that long-term stimulation of the Dopamine D3 receptor in animals induces a strong increase in sucrose consumption, indicating an effect of this receptor on certain pathological aspects of food eating. PMID:25610366

  5. Inulin and erythritol as sucrose replacers in short-dough cookies: sensory, fracture, and acoustic properties.

    PubMed

    Laguna, Laura; Primo-Martín, Cristina; Salvador, Ana; Sanz, Teresa

    2013-05-01

    The effect of sucrose replacement by erythritol and inulin was studied in short-dough cookies using instrumental and sensory analysis. Two levels of replacement were used (25% and 50% of total sucrose content). Descriptive sensory analysis showed that the sucrose replacement affects visual and texture cookies characteristics, being the differences perceived by mouth greater than by hand. In general, sucrose substitutes produced a less crispy cookie and lower consumer acceptability, with the exception of 25% sucrose replacement by inulin. Matrix aeration attributes such as open and crumbly obtained by trained panel were important properties, and correlated positively with consumer acceptance and negatively with maximum force at break (hardness). Inulin cookies sensory properties were more similar to the control than the erythritol cookies. Also, consumer overall acceptance decreased significantly with sucrose replacement by erythritol. The analysis of texture and sound revealed that inulin cookies were softer whereas erythritol cookies were harder in comparison with control cookies; despite this difference, inulin cookies had similar sound characteristics to erythritol cookies.

  6. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

    SciTech Connect

    Scarpace, P.J.; Baresi, L.A.; Morley, J.E. Univ. of California, Los Angeles )

    1987-12-01

    Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the {beta}-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the {beta}-adrenergic pathway, adenylate cyclase activity and {beta}-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. {beta}-Adrenergic receptors were identified in BAT using ({sup 125}I)iodocyanopindolol. Binding sites had the characteristics of mixed {beta}{sub 1}- and {beta}{sub 2}-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in {beta}-adrenergic receptor density due to a loss of the {beta}{sub 1}-adrenergic subtype. This BAT {beta}-adrenergic receptor downregulation was tissue specific, since myocardial {beta}-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of {beta}-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability.

  7. A Conserved Upstream Open Reading Frame Mediates Sucrose-Induced Repression of TranslationW⃞

    PubMed Central

    Wiese, Anika; Elzinga, Nico; Wobbes, Barry; Smeekens, Sjef

    2004-01-01

    Sugars have been shown to regulate transcription of numerous genes in plants. Sucrose controls translation of the group S basic region leucine zipper (bZIP)-type transcription factor ATB2/AtbZIP11 (Rook et al., 1998a). This control requires the unusually long 5′ untranslated region (UTR) of the gene. Point mutations and deletions of the 5′UTR have uncovered the sequences involved. A highly conserved upstream open reading frame (uORF) coding for 42 amino acids is essential for the repression mechanism. It is conserved in 5′UTRs of bZIP transcription factors from other Arabidopsis thaliana genes and many other plants. ATB2/AtbZIP11 is normally expressed in association with vascular tissues. Ectopic expression of a 5′UTR construct shows that the sucrose repression system is functional in all tissues. AtbZIP2 is another Arabidopsis bZIP transcription factor gene harboring the conserved uORF, which is regulated similarly via sucrose-induced repression of translation. This suggests a general function of the conserved uORF in sucrose-controlled regulation of expression. Our findings imply the operation of a sucrose-sensing pathway that controls translation of several plant bZIP transcription factor genes harboring the conserved uORF in their 5′UTRs. Target genes of such transcription factors will then be regulated in sucrose-dependent way. PMID:15208401

  8. Sucrose and raffinose family oligosaccharides (RFOs) in soybean seeds as influenced by genotype and growing location.

    PubMed

    Kumar, Vineet; Rani, Anita; Goyal, Lokesh; Dixit, Amit Kumar; Manjaya, J G; Dev, Jai; Swamy, M

    2010-04-28

    Sucrose content in soybean seeds is desired to be high because as a sweetness-imparting component, it helps in wider acceptance of soy-derived food products. Conversely, galactosyl derivatives of sucrose, that is, raffinose and stachyose, which are flatulence-inducing components, need to be in low concentration in soybean seeds not only for augmenting utilization of the crop in food uses but also for delivering soy meal with improved metabolizable energy for monogastric animals. In the present study, analysis of 148 soybean genotypes for sucrose and total raffinose family oligosaccharides (RFOs) contents revealed a higher variation (4.80-fold) for sucrose than for RFOs content (2.63-fold). High-performance liquid chromatography analyses revealed ranges of 0.64-2.53 and 2.09-7.1 mmol/100 g for raffinose and stachyose contents, respectively. As information concerning the environmental effects on the sucrose and RFOs content in soybean seeds is not available, we also investigated a set of seven genotypes raised at widely different geographical locations for these quality traits. Sucrose content was found to be significantly higher at cooler location (Palampur); however, differences observed for raffinose and stachyose contents across the growing locations were genotype-dependent. The results suggest that soybean genotypes grown at cooler locations may be better suited for processing soy food products with improved taste and flavor. PMID:20353171

  9. Chlorsulfuron modifies biosynthesis of acyl Acid substituents of sucrose esters secreted by tobacco trichomes.

    PubMed

    Kandra, L; Wagner, G J

    1990-11-01

    Sucrose esters and duvatrienediol diterpenes are principal constituents formed in and secreted outside head cells of trichomes occurring on surfaces of Nicotiana tabacum. Using trichome-bearing epidermal peels prepared from midveins of N. tabacum cv T.I. 1068 leaves, we found that chlorsulfuron reduced and modified radiolabeling of sucrose ester acyl acids derived from branched-chain amino acid metabolism. The herbicide did not effect formation and exudation of diterpenes which are products of isoprenoid metabolism. Treatment with 1.0 micromolar chlorsulfuron affected 8.5- and 6.3-fold reductions in radiolabeling of methylvaleryl and methylbutyryl groups of sucrose esters, respectively, and concomitant increases of 9- and 9.8-fold in radiolabeling of straight chain valeryl and butyryl groups, respectively. These results and others indicate that inhibition of acetolactate synthase causes an accumulation of 2-oxo-butyric acid that is utilized by enzymes common to Leu biosynthesis to form 2-oxo-valeric acid. Coenzyme A (CoA) activation of this keto acid gives rise to butyryl CoA, which is utilized to form butyryl containing sucrose esters. Alternatively, reutilization of 2-oxo-valeric acid by the same enzymes followed by CoA activation leads to valeryl containing sucrose esters. We propose that in trichome secretory cells synthase, isomerase and dehydrogenase enzymes which catalyze Leu synthesis/degredation in most tissues, convert iso-branched, anteiso-branched and straight-chain keto acids in the formation of sucrose ester acyl groups. PMID:16667871

  10. Chlorsulfuron Modifies Biosynthesis of Acyl Acid Substituents of Sucrose Esters Secreted by Tobacco Trichomes

    PubMed Central

    Kandra, Lili; Wagner, George J.

    1990-01-01

    Sucrose esters and duvatrienediol diterpenes are principal constituents formed in and secreted outside head cells of trichomes occurring on surfaces of Nicotiana tabacum. Using trichome-bearing epidermal peels prepared from midveins of N. tabacum cv T.I. 1068 leaves, we found that chlorsulfuron reduced and modified radiolabeling of sucrose ester acyl acids derived from branched-chain amino acid metabolism. The herbicide did not effect formation and exudation of diterpenes which are products of isoprenoid metabolism. Treatment with 1.0 micromolar chlorsulfuron affected 8.5- and 6.3-fold reductions in radiolabeling of methylvaleryl and methylbutyryl groups of sucrose esters, respectively, and concomitant increases of 9- and 9.8-fold in radiolabeling of straight chain valeryl and butyryl groups, respectively. These results and others indicate that inhibition of acetolactate synthase causes an accumulation of 2-oxo-butyric acid that is utilized by enzymes common to Leu biosynthesis to form 2-oxo-valeric acid. Coenzyme A (CoA) activation of this keto acid gives rise to butyryl CoA, which is utilized to form butyryl containing sucrose esters. Alternatively, reutilization of 2-oxo-valeric acid by the same enzymes followed by CoA activation leads to valeryl containing sucrose esters. We propose that in trichome secretory cells synthase, isomerase and dehydrogenase enzymes which catalyze Leu synthesis/degredation in most tissues, convert iso-branched, anteiso-branched and straight-chain keto acids in the formation of sucrose ester acyl groups. PMID:16667871

  11. Frequency of sucrose exposure on the cariogenicity of a biofilm-caries model

    PubMed Central

    Díaz-Garrido, Natalia; Lozano, Carla; Giacaman, Rodrigo A.

    2016-01-01

    Objective: Although sucrose is considered the most cariogenic carbohydrate in the human diet, the question of how many exposures are needed to induce damage on the hard dental tissues remains unclear. To approach this question, different frequencies of daily sucrose exposure were tested on a relevant biological caries model. Materials and Methods: Biofilms of the Streptococcus mutans were formed on enamel slabs and exposed to cariogenic challenges with 10% sucrose for 5 min at 0, 1, 3, 5, 8, or 10 times per day. After 5 days, biofilms were retrieved to analyze biomass, protein content, viable bacteria, and polysaccharide formation. Enamel demineralization was evaluated by percentage of microhardness loss (percentage surface hardness loss [%SHL]). Results: Biomass, protein content, polysaccharide production, acidogenicity of the biofilm, and %SHL proportionally increased with the number of daily exposures to sucrose (P < 0.05). One daily sucrose exposure was enough to induce 20% more demineralization than the negative unexposed control. Higher frequencies induced greater demineralization and more virulent biofilms, but eight and ten exposures were not different between them in most of the analyzed variables (P > 0.05). Conclusions: Higher sucrose exposure seems to increase cariogenicity, in a frequency-dependent manner, by the modification of bacterial virulent properties. PMID:27403051

  12. Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9.

    PubMed

    Lin, I Winnie; Sosso, Davide; Chen, Li-Qing; Gase, Klaus; Kim, Sang-Gyu; Kessler, Danny; Klinkenberg, Peter M; Gorder, Molly K; Hou, Bi-Huei; Qu, Xiao-Qing; Carter, Clay J; Baldwin, Ian T; Frommer, Wolf B

    2014-04-24

    Angiosperms developed floral nectaries that reward pollinating insects. Although nectar function and composition have been characterized, the mechanism of nectar secretion has remained unclear. Here we identify SWEET9 as a nectary-specific sugar transporter in three eudicot species: Arabidopsis thaliana, Brassica rapa (extrastaminal nectaries) and Nicotiana attenuata (gynoecial nectaries). We show that SWEET9 is essential for nectar production and can function as an efflux transporter. We also show that sucrose phosphate synthase genes, encoding key enzymes for sucrose biosynthesis, are highly expressed in nectaries and that their expression is also essential for nectar secretion. Together these data are consistent with a model in which sucrose is synthesized in the nectary parenchyma and subsequently secreted into the extracellular space via SWEET9, where sucrose is hydrolysed by an apoplasmic invertase to produce a mixture of sucrose, glucose and fructose. The recruitment of SWEET9 for sucrose export may have been a key innovation, and could have coincided with the evolution of core eudicots and contributed to the evolution of nectar secretion to reward pollinators. PMID:24670640

  13. Expression of peach sucrose transporters in heterologous systems points out their different physiological role.

    PubMed

    Zanon, Laura; Falchi, Rachele; Hackel, Aleksandra; Kühn, Christina; Vizzotto, Giannina

    2015-09-01

    Sucrose is the major phloem-translocated component in a number of economically important plant species. The comprehension of the mechanisms involved in sucrose transport in peach fruit appears particularly relevant, since the accumulation of this sugar, during ripening, is crucial for the growth and quality of the fruit. Here, we report the functional characterisation and subcellular localisation of three sucrose transporters (PpSUT1, PpSUT2, PpSUT4) in peach, and we formulate novel hypotheses about their role in accumulation of sugar. We provide evidence, about the capability of both PpSUT1 and PpSUT4, expressed in mutant yeast strains to transport sucrose. The functionality of PpSUT1 at the plasma membrane, and of PpSUT4 at the tonoplast, has been demonstrated. On the other hand, the functionality of PpSUT2 was not confirmed: this protein is unable to complement two sucrose uptake-deficient mutant yeast strains. Our results corroborate the hypotheses that PpSUT1 partakes in phloem loading in leaves, and PpSUT4 sustains cell metabolism by regulating sucrose efflux from the vacuole. PMID:26259193

  14. Isomaltulose production from sucrose by Protaminobacter rubrum immobilized in calcium alginate.

    PubMed

    de Oliva-Neto, P; Menão, Paula T P

    2009-09-01

    Different culture conditions for Protaminobacter rubrum and enzymatic reaction parameters were evaluated with the goal of improving isomaltulose production. P. rubrum was grown in a medium with 1% (w/v) cane molasses and 0.5% yeast extract and achieved a maximum cell yield Y(x/s) of 0.295 g of cells/g sucrose and a specific growth rate (mu) of 0.192 h(-1). The immobilization of P. rubrum cells was carried out with calcium alginate, glutaraldehyde and polyethyleneimine. Stabile immobilized cell pellets were obtained and used 24 times in batch processes. Enzymatic conversion was carried out at different sucrose concentrations and in pH 6 medium with 70% (w/v) sucrose at 30 degrees C an isomaltulose yield of 89-94% (w/v) was obtained. The specific activity of the P. rubrum immobilized pellets in calcium alginate at 30 degrees C ranged from 1.6 to 4.0 g isomaltulose g(-1) pellet h(-1), respectively with 70% and 65% sucrose solution, while in lower sucrose concentration had higher specific activities presumably due to substrate inhibition of the isomaltulose synthase in higher sucrose concentrations.

  15. Sucrose accelerates flower opening and delays senescence through a hormonal effect in cut lily flowers.

    PubMed

    Arrom, Laia; Munné-Bosch, Sergi

    2012-06-01

    Sugars are generally used to extend the vase life of cut flowers. Such beneficial effects have been associated with an improvement of water relations and an increase in available energy for respiration by floral tissues. In this study we aimed at evaluating to what extent (i) endogenous levels of sugars in outer and inner tepals, androecium and gynoecium are altered during opening and senescence of lily flowers; (ii) sugar levels increase in various floral tissues after sucrose addition to the vase solution; and (iii) sucrose addition alters the hormonal balance of floral tissues. Results showed that endogenous glucose levels increased during flower opening and decreased during senescence in all floral organs, while sucrose levels increased in outer and inner tepals and the androecium during senescence. Sucrose treatment accelerated flower opening, and delayed senescence, but did not affect tepal abscission. Such effects appeared to be exerted through a specific increase in the endogenous levels of sucrose in the gynoecium and of glucose in all floral tissues. The hormonal balance was altered in the gynoecium as well as in other floral tissues. Aside from cytokinin and auxin increases in the gynoecium; cytokinins, gibberellins, abscisic acid and salicylic acid levels increased in the androecium, while abscisic acid decreased in outer tepals. It is concluded that sucrose addition to the vase solution exerts an effect on flower opening and senescence by, among other factors, altering the hormonal balance of several floral tissues.

  16. Generalized gradient and contour program

    USGS Publications Warehouse

    Hellman, Marshall Strong

    1972-01-01

    This program computes estimates of gradients, prepares contour maps, and plots various sets of data provided by the user on the CalComp plotters. The gradients represent the maximum rates of change of a real variable Z=f(X,Y) with respect to the twodimensional rectangle on which the function is defined. The contours are lines of equal Z values. The program also plots special line data sets provided by the user.

  17. Low-gradient aortic stenosis.

    PubMed

    Clavel, Marie-Annick; Magne, Julien; Pibarot, Philippe

    2016-09-01

    An important proportion of patients with aortic stenosis (AS) have a 'low-gradient' AS, i.e. a small aortic valve area (AVA <1.0 cm(2)) consistent with severe AS but a low mean transvalvular gradient (<40 mmHg) consistent with non-severe AS. The management of this subset of patients is particularly challenging because the AVA-gradient discrepancy raises uncertainty about the actual stenosis severity and thus about the indication for aortic valve replacement (AVR) if the patient has symptoms and/or left ventricular (LV) systolic dysfunction. The most frequent cause of low-gradient (LG) AS is the presence of a low LV outflow state, which may occur with reduced left ventricular ejection fraction (LVEF), i.e. classical low-flow, low-gradient (LF-LG), or preserved LVEF, i.e. paradoxical LF-LG. Furthermore, a substantial proportion of patients with AS may have a normal-flow, low-gradient (NF-LG) AS: i.e. a small AVA-low-gradient combination but with a normal flow. One of the most important clinical challenges in these three categories of patients with LG AS (classical LF-LG, paradoxical LF-LG, and NF-LG) is to differentiate a true-severe AS that generally benefits from AVR vs. a pseudo-severe AS that should be managed conservatively. A low-dose dobutamine stress echocardiography may be used for this purpose in patients with classical LF-LG AS, whereas aortic valve calcium scoring by multi-detector computed tomography is the preferred modality in those with paradoxical LF-LG or NF-LG AS. Although patients with LF-LG severe AS have worse outcomes than those with high-gradient AS following AVR, they nonetheless display an important survival benefit with this intervention. Some studies suggest that transcatheter AVR may be superior to surgical AVR in patients with LF-LG AS.

  18. An origin-of-life reactor to simulate alkaline hydrothermal vents.

    PubMed

    Herschy, Barry; Whicher, Alexandra; Camprubi, Eloi; Watson, Cameron; Dartnell, Lewis; Ward, John; Evans, Julian R G; Lane, Nick

    2014-12-01

    Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from vent fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline hydrothermal vents, allowing investigation of the possibility that abiotic vent chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated vent structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow vent conditions.

  19. An origin-of-life reactor to simulate alkaline hydrothermal vents.

    PubMed

    Herschy, Barry; Whicher, Alexandra; Camprubi, Eloi; Watson, Cameron; Dartnell, Lewis; Ward, John; Evans, Julian R G; Lane, Nick

    2014-12-01

    Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from vent fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline hydrothermal vents, allowing investigation of the possibility that abiotic vent chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated vent structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow vent conditions. PMID:25428684

  20. The alkaline earth intercalates of molybdenum disulfide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.; Samson, S.; Woollam, J. A.

    1975-01-01

    Molybdenum disulfide has been intercalated with calcium and strontium by means of the liquid ammonia technique. Chemical, X-ray, and superconductivity data are presented. The X-ray data reveal a lowering of crystal symmetry and increase of complexity of the structure upon intercalation with the alkaline earth metals. The Ca and Sr intercalates start to superconduct at 4 and 5.6 K, respectively, and show considerable anisotropy regarding the critical magnetic field.

  1. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  2. Surfactant-enhanced alkaline flooding field project

    SciTech Connect

    French, T.R.

    1991-10-01

    The Tucker sand of Helper (KS) field is a candidate for surfactant-enhanced alkaline flooding. The geology of the Helper site is typical of many DOE Class I reservoirs. The Tucker sand of Helper field was deposited in a fluvial dominated deltaic environment. Helper oil can be mobilized with either chemical system 2 or chemical system 3, as described in this report. Oil fields in the Gulf Coast region are also good candidates for surfactant-enhanced alkaline flooding. The results from laboratory tests conducted in Berea sandstone cores with oil brine from Helper (KS) field are encouraging. The crude oil is viscous and non-acidic and, yet, was mobilized by the chemical formulations described in this report. Significant amounts of the oil were mobilized under simulated reservoir conditions. The results in Berea sandstone cores were encouraging and should be verified by tests with field core. Consumption of alkali, measured with field core, was very low. Surfactant loss appeared to be acceptable. Despite the good potential for mobilization of Helper oil, certain reservoir characteristics such as low permeability, compartmentalization, and shallow depth place constraints on applications of any chemical system in the Tucker sand. These constraints are typical of many DOE Class I reservoirs. Although Hepler field is not a perfect reservoir in which to apply surfactant- enhanced alkaline flooding, Hepler oil is particularly amenable to mobilization by surfactant-enhanced alkaline systems. A field test is recommended, dependent upon final evaluation of well logs and cores from the proposed pilot area. 14 refs., 21 figs., 10 tabs.

  3. Alkaline flooding for enhanced oil recovery

    SciTech Connect

    Gittler, W.E.

    1983-09-01

    There are over 12 active projects of varying size using one of 3 major types of alkaline agents. These include sodium silicate, caustic soda, and soda ash. Among the largest pilots currently is the THUMS project in the Wilmington field, California. Plans called for the injection of a 4% weight concentration of sodium orthosilicate over a 60% PV. Through the first 3 yr, over 27 million bbl of chemicals have been injected. Gulf Oil is operating several alkaline floods, one of which is located off shore in the Quarantine Bay field, Louisiana. In this pilot, sodium hydroxide in a weight concentration of 5 to 12% is being injected. Belco Petroleum Corp. has reported that their pilot operating in the Isenhour Unit in Wyoming is using a .5% weight concentration of soda ash in conjunction with a polymer. Other uses for alkaline agents in chemical flooding include the use of silicate as a preflush or sacrificial agent in micellar/polymer and surfactant recovery systems. In addition, caustic has been tested in the surface-mixed caustic emulsion process while orthosilicate has been tested in a recovery method known as mobility-controlled caustic floods.

  4. Alkaline injection for enhanced oil recovery: a status report

    SciTech Connect

    Mayer, E.H.; Berg, R.L.; Carmichael, J.D.; Weinbrandt, R.M.

    1983-01-01

    In the past several years, there has been renewed interest in enhanced oil recovery (EOR) by alkaline injection. Alkaline solutions also are being used as preflushes in micellar/polymer projects. Several major field tests of alkaline flooding are planned, are in progress, or recently have been completed. Considerable basic research on alkaline injection has been published recently, and more is in progress. This paper summarizes known field tests and, where available, the amount of alkali injected and the performance results. Recent laboratory work, much sponsored by the U.S. DOE, and the findings are described. Alkaline flood field test plans for new projects are summarized.

  5. Guard cell-specific upregulation of sucrose synthase 3 reveals that the role of sucrose in stomatal function is primarily energetic.

    PubMed

    Daloso, Danilo M; Williams, Thomas C R; Antunes, Werner C; Pinheiro, Daniela P; Müller, Caroline; Loureiro, Marcelo E; Fernie, Alisdair R

    2016-03-01

    Isoform 3 of sucrose synthase (SUS3) is highly expressed in guard cells; however, the precise function of SUS3 in this cell type remains to be elucidated. Here, we characterized transgenic Nicotiana tabacum plants overexpressing SUS3 under the control of the stomatal-specific KST1 promoter, and investigated the changes in guard cell metabolism during the dark to light transition. Guard cell-specific SUS3 overexpression led to increased SUS activity, stomatal aperture, stomatal conductance, transpiration rate, net photosynthetic rate and growth. Although only minor changes were observed in the metabolite profile in whole leaves, an increased fructose level and decreased organic acid levels and sucrose to fructose ratio were observed in guard cells of transgenic lines. Furthermore, guard cell sucrose content was lower during light-induced stomatal opening. In a complementary approach, we incubated guard cell-enriched epidermal fragments in (13) C-NaHCO3 and followed the redistribution of label during dark to light transitions; this revealed increased labeling in metabolites of, or associated with, the tricarboxylic acid cycle. The results suggest that sucrose breakdown is a mechanism to provide substrate for the provision of organic acids for respiration, and imply that manipulation of guard cell metabolism may represent an effective strategy for plant growth improvement. PMID:26467445

  6. Expression patterns, activities and carbohydrate-metabolizing regulation of sucrose phosphate synthase, sucrose synthase and neutral invertase in pineapple fruit during development and ripening.

    PubMed

    Zhang, Xiu-Mei; Wang, Wei; Du, Li-Qing; Xie, Jiang-Hui; Yao, Yan-Li; Sun, Guang-Ming

    2012-01-01

    Differences in carbohydrate contents and metabolizing-enzyme activities were monitored in apical, medial, basal and core sections of pineapple (Ananas comosus cv. Comte de paris) during fruit development and ripening. Fructose and glucose of various sections in nearly equal amounts were the predominant sugars in the fruitlets, and had obvious differences until the fruit matured. The large rise of sucrose/hexose was accompanied by dramatic changes in sucrose phosphate synthase (SPS) and sucrose synthase (SuSy) activities. By contrast, neutral invertase (NI) activity may provide a mechanism to increase fruit sink strength by increasing hexose concentrations. Furthermore, two cDNAs of Ac-sps (accession no. GQ996582) and Ac-ni (accession no. GQ996581) were first isolated from pineapple fruits utilizing conserved amino-acid sequences. Homology alignment reveals that the amino acid sequences contain some conserved function domains. Transcription expression analysis of Ac-sps, Ac-susy and Ac-ni also indicated distinct patterns related to sugar accumulation and composition of pineapple fruits. It suggests that differential expressions of multiple gene families are necessary for sugar metabolism in various parts and developmental stages of pineapple fruit. A cycle of sucrose breakdown in the cytosol of sink tissues could be mediated through both Ac-SuSy and Ac-NI, and Ac-NI could be involved in regulating crucial steps by generating sugar signals to the cells in a temporally and spatially restricted fashion.

  7. Guard cell-specific upregulation of sucrose synthase 3 reveals that the role of sucrose in stomatal function is primarily energetic.

    PubMed

    Daloso, Danilo M; Williams, Thomas C R; Antunes, Werner C; Pinheiro, Daniela P; Müller, Caroline; Loureiro, Marcelo E; Fernie, Alisdair R

    2016-03-01

    Isoform 3 of sucrose synthase (SUS3) is highly expressed in guard cells; however, the precise function of SUS3 in this cell type remains to be elucidated. Here, we characterized transgenic Nicotiana tabacum plants overexpressing SUS3 under the control of the stomatal-specific KST1 promoter, and investigated the changes in guard cell metabolism during the dark to light transition. Guard cell-specific SUS3 overexpression led to increased SUS activity, stomatal aperture, stomatal conductance, transpiration rate, net photosynthetic rate and growth. Although only minor changes were observed in the metabolite profile in whole leaves, an increased fructose level and decreased organic acid levels and sucrose to fructose ratio were observed in guard cells of transgenic lines. Furthermore, guard cell sucrose content was lower during light-induced stomatal opening. In a complementary approach, we incubated guard cell-enriched epidermal fragments in (13) C-NaHCO3 and followed the redistribution of label during dark to light transitions; this revealed increased labeling in metabolites of, or associated with, the tricarboxylic acid cycle. The results suggest that sucrose breakdown is a mechanism to provide substrate for the provision of organic acids for respiration, and imply that manipulation of guard cell metabolism may represent an effective strategy for plant growth improvement.

  8. Effect of different carbon sources on decolourisation of an industrial textile dye under alkaline-saline conditions.

    PubMed

    Ottoni, Cristiane; Lima, Luis; Santos, Cledir; Lima, Nelson

    2014-01-01

    White-rot fungal strains of Trametes versicolor and Phanerochaete chrysosporium were selected to study the decolourisation of the textile dye, Reactive Black 5, under alkaline-saline conditions. Free and immobilised T. versicolor cells showed 100 % decolourisation in the growth medium supplemented with 15 g l(-1) NaCl, pH 9.5 at 30 °C in liquid batch culture. Continuous culture experiments were performed in a fixed-bed reactor using free and immobilised T. versicolor cells and allowed 85-100 % dye decolourisation. The immobilisation conditions for the biomass and the additional supply of carbon sources improved the decolourisation performance during a long-term trial of 40 days. Lignin peroxidase, laccase and glyoxal oxidase activities were detected during the experiments. The laccase activity varied depending on carbon source utilized and glycerol-enhanced laccase activity compared to sucrose during extended growth.

  9. Effects of dietary amylase and sucrose on productivity of cows fed low-starch diets.

    PubMed

    Vargas-Rodriguez, C F; Engstrom, M; Azem, E; Bradford, B J

    2014-07-01

    Recent studies have observed positive effects of both sucrose and exogenous amylase on the productivity of dairy cattle. Our objective was to evaluate direct effects and interactions of amylase and sucrose on dry matter intake (DMI), milk production, and milk components. Forty-eight multiparous Holstein cows between 70 and 130 d in milk were randomly assigned to each of 4 pens (12 cows/pen). Pens were randomly assigned to treatment sequence in a 4 × 4 Latin square design, balanced for carryover effects. Treatment periods were 28 d, with 24 d for diet adaptation and 4d for sample and data collection. The treatments were a control diet (36% NDF and 21% starch), the control diet with amylase [0.5 g/kg of DM; Ronozyme RumiStar 600 (CT); DSM Nutritional Products Ltd., Basel, Switzerland], a diet with sucrose replacing corn grain at 2% of DM, and the sucrose diet with amylase (0.5 g/kg of DM). All data were analyzed with mixed models, including the fixed effects of sugar, amylase, and their interaction, and the random effects of period and pen. Milk data included the random effects of cow nested within pen and pen × period to provide the error term for the pen-level analysis. Dry matter intake was not affected by treatments. Milk yield and milk composition were not altered by the inclusion of sucrose or amylase; however, a tendency for an amylase × sucrose interaction was observed for milk protein content, reflecting slightly lower milk protein concentrations for amylase and sucrose treatments (3.00 and 2.99 ± 0.03%) compared with the control and amylase + sucrose treatments (3.02 and 3.03 ± 0.03%). Solids-corrected and fat-corrected milk yields were not significantly altered by treatment, although the direct effect of amylase approached significance for both variables, suggesting possible small increases with amylase supplementation (~0.5 kg/d). Feed efficiency (energy-corrected milk divided by dry matter intake) numerically increased with either amylase (1.57 ± 0

  10. The fate of added alkalinity in model scenarios of ocean alkalinization

    NASA Astrophysics Data System (ADS)

    Ferrer González, Miriam; Ilyina, Tatiana

    2014-05-01

    The deliberate large-scale manipulation of the Earth's climate (geo-engineering) has been proposed to mitigate climate change and ocean acidification. Whilst the mitigation potential of these technologies could sound promising, they may also pose many environmental risks. Our research aims at exploring the ocean-based carbon dioxide removal method of alkalinity enhancement. Its mitigation potential to reduce atmospheric CO2 and counteract the consequences of ocean acidification, risks and unintended consequences are studied. In order to tackle these questions, different scenarios are implemented in the state-of-the-art Earth system model of the Max Planck Institute for Meteorology. The model configuration is based on the 5th phase of the coupled model intercomparison project following a high CO2 future climate change scenario RCP8.5 (in which radiative forcing rises to 8.5 W/m² in 2100). Two different scenarios are performed where the alkalinity is artificially added globally uniformly in the upper ocean. In the first scenario, alkalinity is increased as a pulse by doubling natural values of the first 12 meters. In the second scenario we add alkalinity into the same ocean layer such that the atmospheric CO2 concentration is reduced from RCP8.5 to RCP4.5 levels (with the radiative forcing of 4.5 W/m² in 2100). We investigate the fate of the added alkalinity in these two scenarios and compare the differences in alkalinity budgets. In order to increase oceanic CO2 uptake from the atmosphere, enhanced alkalinity has to stay in the upper ocean. Once the alkalinity is added, it will become part of the biogeochemical cycles and it will be distributed with the ocean currents. Therefore, we are particularly interested in the residence time of the added alkalinity at the surface. Variations in CO2 partial pressure, seawater pH and saturation state of carbonate minerals produced in the implemented scenarios will be presented. Collateral changes in ocean biogeochemistry and

  11. 40 CFR 230.25 - Salinity gradients.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... estuary. The downstream migration of the salinity gradient can occur, displacing the maximum sedimentation... migration of the salinity gradient displacing the maximim sedimentation zone. This migration may...

  12. 40 CFR 230.25 - Salinity gradients.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... estuary. The downstream migration of the salinity gradient can occur, displacing the maximum sedimentation... migration of the salinity gradient displacing the maximim sedimentation zone. This migration may...

  13. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    PubMed

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.

  14. Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

    SciTech Connect

    Ruiz-Santaquiteria, C.; Fernandez-Jimenez, A.; Palomo, A.

    2012-09-15

    This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

  15. The penetration of inulin, sucrose, mannitol and tritiated water from the interstitial space in muscle into the vascular system

    PubMed Central

    Crone, Christian; Garlick, David

    1970-01-01

    1. An isolated gastrocnemius muscle from cat was perfused with a modified Ringer fluid containing the extracellular tracers mannitol, sucrose and inulin and in some cases tritiated water (HTO). When equilibration of the tracers between the perfusate and the tissue was obtained, perfusion with tracer-free fluid was started. 2. The fractional rate of escape, Φ (t), of the tracers was followed. For all tracers it declined steadily with time. The rate of decline was faster for the smaller extracellular molecules when any combination of two extracellular tracers was studied. 3. Arrest of flow for 1-2 min lead to an increase in Φ (t) for the extracellular tracers when flow was resumed. There was little or no effect upon Φ (t) for HTO. 4. Doubling the rate of flow had no effect upon Φ (t) for the extracellular tracers, while that of HTO increased. 5. We conclude that the cause of the decline in Φ (t) for the extracellular tracers is concentration gradients in the interstitial space. The findings raise problems in methods for studying capillary permeability by means of the fractional rate of escape of tracers from the interstitial space into the vascular system. PMID:5503509

  16. Social defeat-induced anhedonia: effects on operant sucrose-seeking behavior

    PubMed Central

    Riga, Danai; Theijs, J. Trisna; De Vries, Taco J.; Smit, August B.; Spijker, Sabine

    2015-01-01

    Reduced capacity to experience pleasure, also known as anhedonia, is a key feature of the depressive state and is associated with poor disease prognosis and treatment outcome. Various behavioral readouts (e.g., reduced sucrose intake) have been employed in animal models of depression as a measure of anhedonia. However, several aspects of anhedonia are poorly represented within the repertoire of current preclinical assessments. We recently adopted the social defeat-induced persistent stress (SDPS) paradigm that models a maintained depressive-like state in the rat, including social withdrawal and deficits in short-term spatial memory. Here we investigated whether SDPS elicited persistent deficits in natural reward evaluation, as part of anhedonia. We examined cue-paired operant sucrose self-administration, enabling us to study acquisition, motivation, extinction, and relapse to sucrose seeking following SDPS. Furthermore, we addressed whether guanfacine, an α2-adrenergic agonist that reduces stress-triggered maladaptive behavioral responses to drugs of abuse, could relief from SDPS-induced anhedonia. SDPS, consisting of five social defeat episodes followed by prolonged (≥8 weeks) social isolation, did not affect sucrose consumption during acquisition of self-administration. However, it strongly enhanced the motivational drive to acquire a sucrose reward in progressive ratio training. Moreover, SDPS induced initial resilience to extinction and rendered animals more sensitive to cue-induced reinstatement of sucrose-seeking. Guanfacine treatment attenuated SDPS-induced motivational overdrive and limited reinstatement of sucrose seeking, normalizing behavior to control levels. Together, our data indicate that long after the termination of stress exposure, SDPS induces guanfacine-reversible deficits in evaluation of a natural reward. Importantly, the SDPS-triggered anhedonia reflects many aspects of the human phenotype, including impaired motivation and goal

  17. Differences in bingeing behavior and cocaine reward following intermittent access to sucrose, glucose or fructose solutions.

    PubMed

    Rorabaugh, J M; Stratford, J M; Zahniser, N R

    2015-08-20

    Daily intermittent access to sugar solutions results in intense bouts of sugar intake (i.e. bingeing) in rats. Bingeing on sucrose, a disaccharide of glucose and fructose, has been associated with a "primed" mesolimbic dopamine (DA) pathway. Recent studies suggest glucose and fructose engage brain reward and energy-sensing mechanisms in opposing ways and may drive sucrose intake through unique neuronal circuits. Here, we examined in male Sprague-Dawley rats whether or not (1) intermittent access to isocaloric solutions of sucrose, glucose or fructose results in distinctive sugar-bingeing profiles and (2) previous sugar bingeing alters cocaine locomotor activation and/or reward, as determined by conditioned place preference (CPP). To encourage bingeing, rats were given 24-h access to water and 12-h-intermittent access to chow plus an intermittent bottle that contained water (control) or 8% solutions of sucrose, glucose or fructose for 9days, followed by ad libitum chow diet and a 10-day cocaine (15mg/kg; i.p.) CPP paradigm. By day 4 of the sugar-bingeing diet, sugar bingeing in the fructose group surpassed the glucose group, with the sucrose group being intermediate. All three sugar groups had similar chow and water intake throughout the diet. In contrast, controls exhibited chow bingeing by day 5 without altering water intake. Similar magnitudes of cocaine CPP were observed in rats with a history of sucrose, fructose or chow (control) bingeing. Notably, the glucose-bingeing rats did not demonstrate a significant cocaine CPP despite showing similar cocaine-induced locomotor activity as the other diet groups. Overall, these results show that fructose and glucose, the monosaccharide components of sucrose, produce divergent degrees of bingeing and cocaine reward.

  18. Short-term effects of glucose and sucrose on cognitive performance and mood in elderly people.

    PubMed

    van der Zwaluw, Nikita L; van de Rest, Ondine; Kessels, Roy P C; de Groot, Lisette C P G M

    2014-01-01

    In this study we determined the short-term effects of a glucose drink and a sucrose drink compared to a placebo on cognitive performance and mood in elderly people with subjective, mild memory complaints using a randomized crossover study design. In total, 43 nondiabetic older adults with self-reported memory complaints were included. Drinks consisted of 250 ml with dissolved glucose (50 g), sucrose (100 g), or a mixture of artificial sweeteners (placebo). Multiple neuropsychological tests were performed and were combined by means of z scores into four cognitive domains: episodic memory, working memory, attention and information (processing speed), and executive functioning. Mood was assessed with the short Profile of Mood Status (s-POMS) questionnaire. Blood glucose concentrations were measured at five time points to divide participants into those with a better or poorer blood glucose recovery. Performance on the domain of attention and information processing speed was significantly better after consuming the sucrose drink (domain score of 0.06, SD = 0.91) than after the placebo drink (-0.08, SD = 0.92, p = .04). Sucrose had no effect on the other three domains, and glucose had no effect on any of the domains compared to the placebo. When dividing participants into poorer or better glucose recoverers, the beneficial effect of sucrose on attention and information processing speed was only seen in participants with a poorer recovery. After sucrose consumption, depressive feelings and tension were slightly higher than after the placebo. To conclude, 100 g sucrose, but not 50 g glucose, optimized attention and information processing speed in the short term in this study in elderly people with subjective, mild memory complaints.

  19. Short-term effects of glucose and sucrose on cognitive performance and mood in elderly people.

    PubMed

    van der Zwaluw, Nikita L; van de Rest, Ondine; Kessels, Roy P C; de Groot, Lisette C P G M

    2014-01-01

    In this study we determined the short-term effects of a glucose drink and a sucrose drink compared to a placebo on cognitive performance and mood in elderly people with subjective, mild memory complaints using a randomized crossover study design. In total, 43 nondiabetic older adults with self-reported memory complaints were included. Drinks consisted of 250 ml with dissolved glucose (50 g), sucrose (100 g), or a mixture of artificial sweeteners (placebo). Multiple neuropsychological tests were performed and were combined by means of z scores into four cognitive domains: episodic memory, working memory, attention and information (processing speed), and executive functioning. Mood was assessed with the short Profile of Mood Status (s-POMS) questionnaire. Blood glucose concentrations were measured at five time points to divide participants into those with a better or poorer blood glucose recovery. Performance on the domain of attention and information processing speed was significantly better after consuming the sucrose drink (domain score of 0.06, SD = 0.91) than after the placebo drink (-0.08, SD = 0.92, p = .04). Sucrose had no effect on the other three domains, and glucose had no effect on any of the domains compared to the placebo. When dividing participants into poorer or better glucose recoverers, the beneficial effect of sucrose on attention and information processing speed was only seen in participants with a poorer recovery. After sucrose consumption, depressive feelings and tension were slightly higher than after the placebo. To conclude, 100 g sucrose, but not 50 g glucose, optimized attention and information processing speed in the short term in this study in elderly people with subjective, mild memory complaints. PMID:24839862

  20. Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels

    PubMed Central

    Anton, Stephen D.; Martin, Corby K.; Han, Hongmei; Coulon, Sandra; Cefalu, William T.; Geiselman, Paula; Williamson, Donald A.

    2010-01-01

    Consumption of sugar-sweetened beverages may be one of the dietary causes of metabolic disorders, such as obesity. Therefore, substituting sugar with low-calorie sweeteners may be an efficacious weight management strategy. We tested the effect of preloads containing stevia, aspartame, or sucrose on food intake, satiety, and postprandial glucose and insulin levels. Design: 19 healthy lean (BMI = 20.0 – 24.9) and 12 obese (BMI = 30.0 – 39.9) individuals 18 to 50 years old completed three separate food test days during which they received preloads containing stevia (290 kcal), aspartame (290 kcal), or sucrose (493 kcal) before the lunch and dinner meal. The preload order was balanced, and food intake (kcal) was directly calculated. Hunger and satiety levels were reported before and after meals, and every hour throughout the afternoon. Participants provided blood samples immediately before and 20 minutes after the lunch preload. Despite the caloric difference in preloads (290 vs. 493 kcals), participants did not compensate by eating more at their lunch and dinner meals when they consumed stevia and aspartame versus sucrose in preloads (mean differences in food intake over entire day between sucrose and stevia = 301 kcal, p < .01; aspartame = 330 kcal, p < .01). Self-reported hunger and satiety levels did not differ by condition. Stevia preloads significantly lowered postprandial glucose levels compared to sucrose preloads (p < .01), and postprandial insulin levels compared to both aspartame and sucrose preloads (p < .05). When consuming stevia and aspartame preloads, participants did not compensate by eating more at either their lunch or dinner meal and reported similar levels of satiety compared to when they consumed the higher calorie sucrose preload. PMID:20303371

  1. Dietary (n-3) long chain polyunsaturated fatty acids prevent sucrose-induced insulin resistance in rats.

    PubMed

    Ghafoorunissa; Ibrahim, Ahamed; Rajkumar, Laxmi; Acharya, Vani

    2005-11-01

    This study was designed to determine the effect of substituting (n-3) long-chain PUFAs (LCPUFAs) for linoleic acid and hence decreasing the (n-6):(n-3) fatty acid ratio on sucrose-induced insulin resistance in rats. Weanling male Wistar rats were fed casein-based diets containing 100 g/kg fat for 12 wk. Insulin resistance was induced by replacing starch (ST) with sucrose (SU). The dietary fats were formulated with groundnut oil, palmolein, and fish oil to provide the following ratios of (n-6):(n-3) fatty acids: 210 (ST-210, SU-210), 50 (SU-50), 10 (SU-10), and 5 (SU-5). Compared with starch (ST-210), sucrose feeding (SU-210) significantly increased the plasma insulin and triglyceride concentrations and the plasma insulin area under the curve (AUC) in response to an oral glucose load. Adipocytes isolated from rats fed SU-210 had greater lipolytic rate, lower insulin stimulated glucose transport, and lower insulin-mediated antilipolysis than those from rats fed ST-210. Decreasing the dietary (n-6):(n-3) ratio in sucrose-fed rats (SU-10 and SU-5) normalized the plasma insulin concentration and the AUC of insulin after a glucose load. The sucrose-induced increase in plasma triglyceride concentration was normalized in rats fed SU-50, SU-10 and SU-5. Further, sucrose-induced alterations in adipocyte lipolysis and antilipolysis were partially reversed and glucose transport improved in rats fed diets SU-5 and SU-10. In diaphragm phospholipids, decreasing the (n-6):(n-3) ratio in the diet increased the concentration of (n-3) LCPUFAs with concomitant decreases in the concentration of (n-6) LCPUFAs. These results suggest that (n-3) LCPUFAs at a level of 2.6 g/kg diet [0.56% energy (n-3) LCPUFAs, (n-6):(n-3) ratio = 10] may prevent sucrose-induced insulin resistance by improving peripheral insulin sensitivity.

  2. Metabolic engineering of Ralstonia eutropha for the production of polyhydroxyalkanoates from sucrose.

    PubMed

    Park, Si Jae; Jang, Young-Ah; Noh, Won; Oh, Young Hoon; Lee, Hyuk; David, Yokimiko; Baylon, Mary Grace; Shin, Jihoon; Yang, Jung Eun; Choi, So Young; Lee, Seung Hwan; Lee, Sang Yup

    2015-03-01

    A sucrose utilization pathway was established in Ralstonia eutropha NCIMB11599 and R. eutropha 437-540 by introducing the Mannheimia succiniciproducens MBEL55E sacC gene that encodes β-fructofuranosidase. These engineered strains were examined for the production of poly(3-hydroxybutyrate) [P(3HB)] and poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)], respectively, from sucrose as a carbon source. It was found that β-fructofuranosidase excreted into the culture medium could hydrolyze sucrose to glucose and fructose, which were efficiently used as carbon sources by recombinant R. eutropha strains. When R. eutropha NCIMB11599 expressing the sacC gene was cultured in nitrogen-free chemically defined medium containing 20 g/L of sucrose, a high P(3HB) content of 73.2 wt% could be obtained. In addition, R. eutropha 437-540 expressing the Pseudomonas sp. MBEL 6-19 phaC1437 gene and the Clostridium propionicum pct540 gene accumulated P(3HB-co-21.5 mol% LA) to a polymer content of 19.5 wt% from sucrose by the expression of the sacC gene and the Escherichia coli ldhA gene. The molecular weights of P(3HB) and P(3HB-co-21.5 mol%LA) synthesized in R. eutropha using sucrose as a carbon source were 3.52 × 10(5) (Mn ) and 2.19 × 10(4) (Mn ), respectively. The engineered R. eutropha strains reported here will be useful for the production of polyhydroxyalkanoates (PHAs) from sucrose, one of the most abundant and relatively inexpensive carbon sources.

  3. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure.

    PubMed

    Scarpace, P J; Baresi, L A; Morley, J E

    1987-12-01

    Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the beta-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the beta-adrenergic pathway, adenylate cyclase activity and beta-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. beta-Adrenergic receptors were identified in BAT using [125I]iodocyanopindolol. Binding sites had the characteristics of mixed beta 1- and beta 2-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in beta-adrenergic receptor density due to a loss of the beta 1-adrenergic subtype. This BAT beta-adrenergic receptor downregulation was tissue specific, since myocardial beta-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. In contrast, food deprivation did not alter BAT beta-adrenergic receptor density. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. The ratio of isoproterenol-stimulated to forskolin-stimulated adenylate cyclase activity decreased in the sucrose-fed and cold-exposed rats but not in the food-deprived rats. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of beta-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability. PMID:2827501

  4. Comparison and validation of two analytical methods for measurement of urinary sucrose and fructose excretion

    PubMed Central

    Song, Xiaoling; Navarro, Sandi L.; Diep, Pho; Thomas, Wendy K.; Razmpoosh, Elena C.; Schwarz, Yvonne; Wang, Ching-Yun; Kratz, Mario; Neuhouser, Marian L.; Lampe, Johanna W.

    2013-01-01

    Urinary sugars excretion has been proposed as a potential biomarker for intake of sugars. In this study we compared two analytical methods [gas chromatography (GC) and enzymatic reactions – UV absorption] for quantifying urinary fructose and sucrose using 24-hour urine samples from a randomized cross-over controlled feeding study. All samples were successfully quantified by the GC method; however 21% and 1.9% of samples were below the detection limit of the enzymatic method for sucrose and fructose, respectively. While the correlation between the two methods was good for fructose (Pearson correlation 0.71), the correlation was weak for sucrose (Pearson correlation 0.27). We favor the GC method due to its better sensitivity, simplicity, and the ability to quantify fructose and sucrose directly in the same run. Of the 106 samples from 53 participants with complete urine collection after two study diets, 24-hour urinary fructose excretion was significantly associated with fructose intake. The sum of 24-hour urinary fructose and sucrose was significantly associated with total sugars consumption. However, variation in intakes of sugars explained only a modest amount of variation in urinary sugars excretion. In the unadjusted models, fructose intake explained 24.3% of urinary fructose excretion; and intake of total sugars 16.3% of the sum of urinary fructose and sucrose. The adjusted models explained 44.3% of urinary fructose excretion and 41.7% of the sum of urinary fructose and sucrose. Therefore, we caution using these biomarkers to predict sugars consumption before other factors that determine urinary sugars excretion are understood. PMID:24034568

  5. Efficacy and safety of intravenous iron sucrose in treating adults with iron deficiency anemia

    PubMed Central

    Cançado, Rodolfo Delfini; de Figueiredo, Pedro Otavio Novis; Olivato, Maria Cristina Albe; Chiattone, Carlos Sérgio

    2011-01-01

    Background Iron deficiency is the most common disorder in the world, affecting approximately 25% of the world`s population and the most common cause of anemia. Objective To evaluate the efficacy and safety of intravenous iron sucrose (IS) in the treatment of adults with iron deficiency anemia Methods Eighty-six adult patients with iron deficiency anemia, who had intolerance or showed no effect with oral iron therapy, received a weekly dose of 200 mg of intravenous iron sucrose until the hemoglobin level was corrected or until receiving the total dose of intravenous iron calculated for each patient Results The mean hemoglobin and serum ferritin levels were 8.54 g/dL and 7.63 ng/mL (pre-treatment) and 12.1 g/dL and 99.0 ng/mL (post-treatment) (p-value < 0.0001), respectively. The average increases in hemoglobin levels were 3.29 g/dL for women and 4.58 g/dL for men; 94% of male and 84% of female patients responded (hemoglobin increased by at least 2 g/dL) to intravenous iron therapy. Correction of anemia was obtained in 47 of 69 (68.1%) female patients and in 12 of 17 male (70.6%) patients. A total of 515 intravenous infusions of iron sucrose were administered and iron sucrose was generally well tolerated with no moderate or serious adverse drug reactions recorded by the investigators. Conclusions Our data confirm that the use of intravenous iron sucrose is a safe and effective option in the treatment of adult patients with iron deficiency anemia who lack satisfactory response to oral iron therapy. Intravenous iron sucrose is well tolerated and with a clinically manageable safety profile when using appropriate dosing and monitoring. The availability of intravenous iron sucrose would potentially improve compliance and thereby reduce morbidities from iron deficiency. PMID:23049360

  6. Long-term landscape evolution of the southeast Brazilian highlands: comparison of two alkaline intrusions areas

    NASA Astrophysics Data System (ADS)

    Doranti Tiritan, Carolina; Hackspacher, Peter Christian; Glasmacher, Ulrich Anton

    2016-04-01

    . In the SSI area the crystalline basement registered ages 121.1±11.5 Ma and 49.4±4.8 while the alkaline stocks ages ranges 112.5±13; 91.1±11.2Ma; 89.4±13.4 88.2±8.5; 71.3±7.9. The results shows that the main difference between the areas is that PCAM region register older history then the coastal area of SSI, where thermal history starts register cooling event after the South Atlantic rifting process, while in the PCAM area register a previous history, since Carboniferous. The age-elevation relationship shows that the ages decrease systematically with increasing elevation with a break-in-slope near the 150Ma, 80Ma and around 50Ma, which means that the landscape evolution can be associated with several distinct exhumation events at the South American passive continental margin, which include the Gondwana break-up, the Late Cretaceous alkaline magmatism, and the Cenozoic evolution of a N-S trending continental graben system. We are thankful to CAPES/PROBRAL/ processo 12809/13-6, Marli Carina Siqueira Ribeiro, IGCE-UNESP; Earth Sciences Institut, Heidelberg University; References DORANTI-TIRITAN, C. , et al (2014) The Use of the Stream Length-Gradient Index in Morphotectonic Analysis of Drainage Basins in Poços de Caldas Plateau, SE Brazil. International Journal of Geosciences, 5, 1383-1394. doi: 10.4236/ijg.2014.511112 HACKSPACHER, P.C; et al. (2004) Consolidation and Break-Up of The South American Platform in Southeastern Brazil: Tectonothermal and Denudation Histories. Gondwana Research -N°1, P. 91 -101.

  7. Rapid Gradient-Echo Imaging

    PubMed Central

    Hargreaves, Brian

    2012-01-01

    Gradient echo sequences are widely used in magnetic resonance imaging (MRI) for numerous applications ranging from angiography to perfusion to functional MRI. Compared with spin-echo techniques, the very short repetition times of gradient-echo methods enable very rapid 2D and 3D imaging, but also lead to complicated “steady states.” Signal and contrast behavior can be described graphically and mathematically, and depends strongly on the type of spoiling: fully balanced (no spoiling), gradient spoiling, or RF-spoiling. These spoiling options trade off between high signal and pure T1 contrast while the flip angle also affects image contrast in all cases, both of which can be demonstrated theoretically and in image examples. As with spin-echo sequences, magnetization preparation can be added to gradient-echo sequences to alter image contrast. Gradient echo sequences are widely used for numerous applications such as 3D perfusion imaging, functional MRI, cardiac imaging and MR angiography. PMID:23097185

  8. Gradient Domain Guided Image Filtering.

    PubMed

    Kou, Fei; Chen, Weihai; Wen, Changyun; Li, Zhengguo

    2015-11-01

    Guided image filter (GIF) is a well-known local filter for its edge-preserving property and low computational complexity. Unfortunately, the GIF may suffer from halo artifacts, because the local linear model used in the GIF cannot represent the image well near some edges. In this paper, a gradient domain GIF is proposed by incorporating an explicit first-order edge-aware constraint. The edge-aware constraint makes edges be preserved better. To illustrate the efficiency of the proposed filter, the proposed gradient domain GIF is applied for single-image detail enhancement, tone mapping of high dynamic range images and image saliency detection. Both theoretical analysis and experimental results prove that the proposed gradient domain GIF can produce better resultant images, especially near the edges, where halos appear in the original GIF. PMID:26285153

  9. Carbohydrate profiling in seeds and seedlings of transgenic triticale modified in the expression of sucrose:sucrose-1-fructosyltransferase (1-SST) and sucrose:fructan-6-fructosyltransferase (6-SFT).

    PubMed

    Diedhiou, Calliste; Gaudet, Denis; Liang, Yehong; Sun, Jinyue; Lu, Zhen-Xing; Eudes, François; Laroche, André

    2012-10-01

    Constructs with sucrose-sucrose 1-fructosyltransferase (1-SST) from rye and or sucrose-fructan 6-fructosyltransferase (6-SFT) from wheat were placed under the control of wheat aleurone-specific promoter and expressed in triticale using biolistic and microspore transformation. Transgenic lines expressing one or both the 1-SST and the 6-SFT accumulated 50% less starch and 10-20 times more fructan, particularly 6-kestose, in the dry seed compared to the untransformed wild-type (WT) triticale; other fructans ranged in size from DP 4 to DP 15. During germination from 1 to 4 days after imbibition (dai), fructans were rapidly metabolized and only in transgenic lines expressing both 1-SST and 6-SFT were fructan contents significantly higher than in the untransformed controls after 4 days. In situ hybridization confirmed expression of 6-SFT in the aleurone layer in imbibed seeds of transformed plants. When transgenic lines were subjected to a cold stress of 4°C for 2 days, synthesis of fructan increased compared to untransformed controls during low-temperature germination. The increase of fructan in dry seed and germinating seedling was generally associated with transcript expression levels in transformed plants but total gene expression was not necessarily correlated with the time course accumulation of fructan during germination. This is the first report of transgenic modification of cereals to achieve production of fructans in cereal seeds and during seed germination.

  10. Continuous acidogenesis of sucrose, raffinose and vinasse using mineral kissiris as promoter.

    PubMed

    Lappa, Katerina; Kandylis, Panagiotis; Bekatorou, Argyro; Bastas, Nikolaos; Klaoudatos, Stavros; Athanasopoulos, Nikolaos; Kanellaki, Maria; Koutinas, Athanasios A

    2015-01-01

    The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52 °C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37 °C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2 months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14 g/L and ethanol concentrations were 0.5-1 mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes. PMID:25748017

  11. Influence of solid-state acidity on the decomposition of sucrose in amorphous systems. I.

    PubMed

    Alkhamis, Khouloud A

    2008-10-01

    It was of interest to develop a method for solid-state acidity measurements using pH indicators and to correlate this method to the degradation rate of sucrose. Amorphous samples containing lactose 100mg/ml, sucrose 10mg/ml, citrate buffer (1-50mM) and sodium chloride (to adjust the ionic strength) were prepared by freeze-drying. The lyophiles were characterized using powder X-ray diffraction, differential scanning calorimetry and Karl Fischer titremetry. The solid-state acidity of all lyophiles was measured using diffuse reflectance spectroscopy and suitable indicators (thymol blue or bromophenol blue). The prepared lyophiles were subjected to a temperature of 60 degrees C and were analyzed for degradation using the Trinder kit. The results obtained from this study have shown that the solid-state acidity depends mainly on the molar ratio of the salt and the acid used in buffer preparation and not on the initial pH of the solution. The degradation of sucrose in the lyophiles is extremely sensitive to the solid-state acidity and the ionic strength. Reasonable correlation was obtained between the Hammett acidity function and sucrose degradation rate. The use of cosolvents (in the calibration plots) can provide good correlations with the rate of an acid-catalyzed reaction, sucrose inversion, in amorphous lyophiles. PMID:18647642

  12. Activation of physiological stress responses by a natural reward: Novel vs. repeated sucrose intake.

    PubMed

    Egan, Ann E; Ulrich-Lai, Yvonne M

    2015-10-15

    Pharmacological rewards, such as drugs of abuse, evoke physiological stress responses, including increased heart rate and blood pressure, and activation of the hypothalamic-pituitary-adrenal (HPA) axis. It is not clear to what extent the natural reward of palatable foods elicits similar physiological responses. In order to address this question, HPA axis hormones, heart rate, blood pressure and brain pCREB immunolabeling were assessed following novel and repeated sucrose exposure. Briefly, adult, male rats with ad libitum food and water were given either a single (day 1) or repeated (twice-daily for 14 days) brief (up to 30 min) exposure to a second drink bottle containing 4 ml of 30% sucrose drink vs. water (as a control for bottle presentation). Sucrose-fed rats drank more than water-fed on all days of exposure, as expected. On day 1 of exposure, heart rate, blood pressure, plasma corticosterone, and locomotion were markedly increased by presentation of the second drink bottle regardless of drink type. After repeated exposure (day 14), these responses habituated to similar extents regardless of drink type and pCREB immunolabeling in the hypothalamic paraventricular nucleus (PVN) also did not vary with drink type, whereas basolateral amygdala pCREB was increased by sucrose intake. Taken together, these data suggest that while sucrose is highly palatable, physiological stress responses were evoked principally by the drink presentation itself (e.g., an unfamiliar intervention by the investigators), as opposed to the palatability of the offered drink.

  13. Heavy-ion-induced sucrose radicals investigated using EPR and UV spectroscopy.

    PubMed

    Nakagawa, Kouichi; Karakirova, Yordanka; Yordanov, Nicola D

    2015-05-01

    The potential use of a sucrose dosimeter for estimating both linear energy transfer (LET) and the absorbed dose of heavy ion and X-ray radiation was investigated. The stable free radicals were produced when sucrose was irradiated with heavy ions, such as helium, carbon, silicon and neon ions, and when the X-ray radiation was similar to the obtained electron paramagnetic resonance (EPR) spectra, which were ∼7 mT wide and composed of several hyperfine structures. In addition, the total spin concentration resulting from heavy-ion irradiation increased linearly as the absorbed dose increased, and decreased logarithmically as the LET increased. These empirical relations imply that the LET at a certain dose can be determined from the spin concentration. For sucrose and alanine, both cross-sections following C-ion irradiation with a 50 Gy dose were ∼1.3 × 10(-12) [μm(2)], taking into account the molecular size of the samples. The values of these cross-sections imply that multiple ionizing particles were involved in the production of stable radicals. Furthermore, UV absorbance at 267 nm of an aqueous solution of irradiated sucrose was found to linearly increase with increasing absorbed dose. Therefore, the EPR and UV results suggest that sucrose can be a useful dosimeter for heavy-ion irradiation.

  14. Continuous acidogenesis of sucrose, raffinose and vinasse using mineral kissiris as promoter.

    PubMed

    Lappa, Katerina; Kandylis, Panagiotis; Bekatorou, Argyro; Bastas, Nikolaos; Klaoudatos, Stavros; Athanasopoulos, Nikolaos; Kanellaki, Maria; Koutinas, Athanasios A

    2015-01-01

    The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52 °C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37 °C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2 months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14 g/L and ethanol concentrations were 0.5-1 mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes.

  15. Electrospun gelatin nanofibers: a facile cross-linking approach using oxidized sucrose.

    PubMed

    Jalaja, K; James, Nirmala R

    2015-02-01

    Gelatin nanofibers were fabricated via electrospinning with minimal toxicity from solvents and cross-linking agents. Electrospinning was carried out using a solvent system based on water and acetic acid (8:2, v/v). Acetic acid concentration was kept as minimum as possible to reduce the toxic effects. Electrospun gelatin nanofibers were cross-linked with oxidized sucrose. Sucrose was oxidized by periodate oxidation to introduce aldehyde functionality. Cross-linking with oxidized sucrose could be achieved without compromising the nanofibrous architecture. Cross-linked gelatin nanofibers maintained the fibrous morphology even after keeping in contact with aqueous medium. The morphology of the cross-linked nanofibrous mats was examined by scanning electron microscopy (SEM). Oxidized sucrose cross-linked gelatin nanofibers exhibited improved thermal and mechanical properties. The nanofibrous mats were evaluated for cytotoxicity and cell viability using L-929 fibroblast cells. The results confirmed that oxidized sucrose cross-linked gelatin nanofibers were non-cytotoxic towards L-929 cells with good cell viability.

  16. Reinforcer magnitude (sucrose concentration) and the matching law theory of response strength.

    PubMed

    Heyman, G M; Monaghan, M M

    1994-05-01

    This experiment investigated the relationship between reinforcer magnitude (sucrose concentration) and response rate. The purpose was to evaluate the behavior of two parameters of an equation that predicts absolute response rate as a function of reinforcement rate and two free parameters. According to Herrnstein's (1970) theory of reinforced behavior, one parameter of this "response-strength equation" measures the efficacy of the reinforcer maintaining responding and the other parameter measures motoric components of response rate, such as response duration. Seven rats served as subjects. Experimental sessions consisted of a series of five different variable-interval schedules of reinforcement, each in effect for 5 minutes. Within each session, obtained reinforcement rates varied over more than a 30-fold range, from about 20 per hour to 700 per hour. The reinforcer was sucrose solution, and, between sessions, its concentration was varied from 0.0 to 0.64 molar (0 to 21.9%). For sucrose concentrations of 0.16 to 0.64 m, response rate was a negatively accelerated function of reinforcement rate. Increases in sucrose concentration increased response rates maintained by low but not high reinforcement rates. This pattern of changes corresponds to a change in the reinforcement-efficacy parameter of the response-strength equation. In contrast, the motor-performance parameter did not change as a function of sucrose concentration. These findings are inconsistent with the results of a similar study (Bradshaw, Szabadi, & Bevan, 1978) but support Herrnstein's theory of reinforced behavior.

  17. Electrical stimulation of the lateral habenula produces an inhibitory effect on sucrose self-administration.

    PubMed

    Friedman, Alexander; Lax, Elad; Dikshtein, Yahav; Abraham, Lital; Flaumenhaft, Yakov; Sudai, Einav; Ben-Tzion, Moshe; Yadid, Gal

    2011-01-01

    The lateral habenula (LHb) plays a role in prediction of negative reinforcement, punishment and aversive responses. In the current study, we examined the role that the LHb plays in regulation of negative reward responses and aversion. First, we tested the effect of intervention in LHb activity on sucrose reinforcing behavior. An electrode was implanted into the LHb and rats were trained to self-administer sucrose (20%; 16 days) until at least three days of stable performance were achieved (as represented by the number of active lever presses in self-administration cages). Rats subsequently received deep brain stimulation (DBS) of the LHb, which significantly reduced sucrose self-administration levels. In contrast, lesion of the LHb increased sucrose-seeking behavior, as demonstrated by a delayed extinction response to substitution of sucrose with water. Furthermore, in a modified non-rewarding conditioned-place-preference paradigm, DBS of the LHb led to aversion to the context associated with stimulation of this brain region. We postulate that electrical stimulation of the LHb attenuates positive reward-associated reinforcement by natural substances. PMID:20955718

  18. Synthesis of fructooligosaccharides in banana 'prata' and its relation to invertase activity and sucrose accumulation.

    PubMed

    Der Agopian, Roberta Ghedini; Purgatto, Eduardo; Cordenunsi, Beatriz Rosana; Lajolo, Franco Maria

    2009-11-25

    Levels of sucrose and total fructooligosaccharides (FOS) were quantified in different phases of banana 'Prata' ripening during storage at ambient (approximately 19 degrees C) and low (approximately 10 degrees C) temperature. Total FOS levels were detected in the first days after harvest, whereas 1-kestose remained undetectable until the sucrose levels reached approximately 200 mg/g (dry weight) in both groups. Sucrose levels increased slowly but constantly at low temperature, but they elevated rapidly when the temperature was raised to 19 degrees C. Total FOS and sucrose levels were higher in bananas stored at low temperature than in the control group. In both samples, total FOS levels were higher than those of 1-kestose. The carbohydrate profiles obtained by HPLC and TLC suggest the presence of neokestose, 6-kestose, and bifurcose. The enzymes putatively involved in banana fructosyltransferase activity were also evaluated. Results obtained indicate that the banana enzyme responsible for the synthesis of FOS by transfructosylation is an invertase rather than a sucrose-sucrosyl transferase-like enzyme. PMID:19860446

  19. Evidence that high-sucrose diet reduces dentin formation and disturbs mineralization in rat molars.

    PubMed

    Hietala, E L; Larmas, M

    1995-12-01

    In addition to its caries-promoting effect, a high-sucrose diet reduces the apposition of mineralized dentin in young rats. This study was undertaken to test whether it has a similar effect on the width of the as-yet-uncalcified matrix, predentin. Female Wistar rats were weaned at the age of 3 weeks and fed for 7 weeks with either a high-sucrose diet, a non-cariogenic raw potato starch diet, or a non-cariogenic commercial powdered rat food (for reference). The sucrose diet induced the greatest number of caries lesions. Dentin formation was smaller and the predentin zone wider in rats fed a sucrose diet when compared with rats fed the reference diet. In rats fed a starch diet, dentin formation was smaller than in rats fed a reference diet, but no alterations in the areas of caries lesions or predentin width were observed. Widening of the predentin zone in rats fed a high-sucrose diet may reflect changes in odontoblast function, such as reduced matrix synthesis and possibly disturbed mineralization. Dentinal caries progression may thus be modulated by odontoblast function, not as much by matrix formation but rather by mineralization.

  20. Impact of adolescent sucrose access on cognitive control, recognition memory, and parvalbumin immunoreactivity

    PubMed Central

    Killcross, Simon; Hambly, Luke D.; Morris, Margaret J.; Westbrook, R. Fred

    2015-01-01

    In this study we sought to determine the effect of daily sucrose consumption in young rats on their subsequent performance in tasks that involve the prefrontal cortex and hippocampus. High levels of sugar consumption have been associated with the development of obesity, however less is known about how sugar consumption influences behavioral control and high-order cognitive processes. Of particular concern is the fact that sugar intake is greatest in adolescence, an important neurodevelopmental period. We provided sucrose to rats when they were progressing through puberty and adolescence. Cognitive performance was assessed in adulthood on a task related to executive function, a rodent analog of the Stroop task. We found that sucrose-exposed rats failed to show context-appropriate responding during incongruent stimulus compounds presented at test, indicative of impairments in prefrontal cortex function. Sucrose exposed rats also showed deficits in an on object-in-place recognition memory task, indicating that both prefrontal and hippocampal function was impaired. Analysis of brains showed a reduction in expression of parvalbumin-immunoreactive GABAergic interneurons in the hippocampus and prefrontal cortex, indicating that sucrose consumption during adolescence induced long-term pathology, potentially underpinning the cognitive deficits observed. These results suggest that consumption of high levels of sugar-sweetened beverages by adolescents may also impair neurocognitive functions affecting decision-making and memory, potentially rendering them at risk for developing mental health disorders. PMID:25776039