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Sample records for arabidopsis sucrose transporters

  1. Functional Analysis of Arabidopsis Sucrose Transporters

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    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.

  2. Interactions between co-expressed Arabidopsis sucrose transporters in the split-ubiquitin system

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    Lalonde Sylvie

    2003-03-01

    Full Text Available Abstract Background The Arabidopsis genome contains nine sucrose transporter paralogs falling into three clades: SUT1-like, SUT2 and SUT4. The carriers differ in their kinetic properties. Many transport proteins are known to exist as oligomers. The yeast-based split ubiquitin system can be used to analyze the ability of membrane proteins to interact. Results Promoter-GUS fusions were used to analyze the cellular expression of the three transporter genes in transgenic Arabidopsis plants. All three fusion genes are co-expressed in companion cells. Protein-protein interactions between Arabidopsis sucrose transporters were tested using the split ubiquitin system. Three paralogous sucrose transporters are capable of interacting as either homo- or heteromers. The interactions are specific, since a potassium channel and a glucose transporter did not show interaction with sucrose transporters. Also the biosynthetic and metabolizing enzymes, sucrose phosphate phosphatase and sucrose synthase, which were found to be at least in part bound to the plasma membrane, did not specifically interact with sucrose transporters. Conclusions The split-ubiquitin system provides a powerful tool to detect potential interactions between plant membrane proteins by heterologous expression in yeast, and can be used to screen for interactions with membrane proteins as baits. Like other membrane proteins, the Arabidopsis sucrose transporters are able to form oligomers. The biochemical approaches are required to confirm the in planta interaction.

  3. Arabidopsis Sucrose Transporter SUT4 Interacts with Cytochrome b5-2 to Regulate Seed Germination in Response to Sucrose and Glucose

    Institute of Scientific and Technical Information of China (English)

    Yan Li; Ling-Li Li; Ren-Chun Fan; Chang-Cao Peng; Hai-Li Sun; Sai-Yong Zhu; Xiao-Fang Wang; Ling-Yun Zhang; Da-Peng Zhang

    2012-01-01

    It remains unknown whether a sucrose transporter mediates sugar signaling.Here,we report that the Arabidopsis (Arabidopsis thaliana) sucrose transporter SUT4 interacts with five members of the Arabidopsis cytochrome b5(Cyb5) family,and sucrose represses the interaction between SUT4 and a Cyb5 member Cyb5-2/A.We observed that downregulation of SUT4 and three cytochrome b5 members (Cyb5-2,Cyb5-4,and Cyb5-6) confers the sucrose-and glucoseinsensitive phenotypes in the sucrose/glucose-induced inhibition of seed germination.The sut4 cyb5-2 double mutant displays slightly stronger sucrose/glucose-insensitive phenotypes than either the sut4 or cyb5-2 single mutant.We showed that the SUT4/Cyb5-2-mediated signaling in the sucrose/glucose-induced inhibition of seed germination does not require ABA or the currently known ABI2/ABI4/ABI5-mediated signaling pathway(s).These data provide evidence that the sucrose transporter SUT4 interacts with Cyb5 to positively mediate sucrose and glucose signaling in the sucrose/glucose-induced inhibition of seed germination.

  4. Carbon-14 labelled sucrose transportation in an Arabidopsis thaliana using an imaging plate and real time imaging system

    International Nuclear Information System (INIS)

    As an approach to increased production of rape seed oil from Brassica napus L., Arabidopsis thaliana, a species from the same Brassicaceae family, was used to investigate transport behavior and distribution of matter in the plant body. In this study, sucrose, an initial metabolic product of photosynthesis, labeled with carbon-14 was used. The sucrose was applied to A. thaliana via the surface of a rosette leaf. Using the real time radioisotope imaging system we developed and an imaging plate (IP), images of whole or part of the sample were obtained. The sucrose assimilation products were accumulated in maturing tissue such as flowers and fruits, and in a joint part. From the comparison among branches and stems, it was indicated that there were different patterns of demand and distribution of sucrose assimilation products depending on the tissue and its growing stage. This might be caused by either morphological reason such as diameter and location of the sieve tube, or genetic factors such as an activity of a membrane transport protein. Because of self-absorption of carpels, it was difficult to observe the accumulation of carbon-14 in the seeds inside the fruits; however, an IP image of a frozen section of a fruit revealed that carbon-14 transport to seeds was higher than that of carpels. These methods will help us gain insight into matter transport and strategies to improve the production of rape seed oil. (author)

  5. Water Deficit Enhances C Export to the Roots in Arabidopsis thaliana Plants with Contribution of Sucrose Transporters in Both Shoot and Roots.

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    Durand, Mickaël; Porcheron, Benoît; Hennion, Nils; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2016-03-01

    Root high plasticity is an adaptation to its changing environment. Water deficit impairs growth, leading to sugar accumulation in leaves, part of which could be available to roots via sucrose (Suc) phloem transport. Phloem loading is widely described in Arabidopsis (Arabidopsis thaliana), while unloading in roots is less understood. To gain information on leaf-to-root transport, a soil-based culture system was developed to monitor root system architecture in two dimensions. Under water deficit (50% of soil water-holding capacity), total root length was strongly reduced but the depth of root foraging and the shape of the root system were less affected, likely to improve water uptake. (14)CO2 pulse-chase experiments confirmed that water deficit enhanced carbon (C) export to the roots, as suggested by the increased root-to-shoot ratio. The transcript levels of AtSWEET11 (for sugar will eventually be exported transporter), AtSWEET12, and AtSUC2 (for Suc carrier) genes, all three involved in Suc phloem loading, were significantly up-regulated in leaves of water deficit plants, in accordance with the increase in C export from the leaves to the roots. Interestingly, the transcript levels of AtSUC2 and AtSWEET11 to AtSWEET15 were also significantly higher in stressed roots, underlying the importance of Suc apoplastic unloading in Arabidopsis roots and a putative role for these Suc transporters in Suc unloading. These data demonstrate that, during water deficit, plants respond to growth limitation by allocating relatively more C to the roots to maintain an efficient root system and that a subset of Suc transporters is potentially involved in the flux of C to and in the roots. PMID:26802041

  6. A novel fluorescent assay for sucrose transporters

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    Gora Peter J

    2012-04-01

    Full Text Available Abstract Background We have developed a novel assay based on the ability of type I sucrose uptake transporters (SUTs to transport the fluorescent coumarin β-glucoside, esculin. Budding yeast (Saccharomyces cerevisiae is routinely used for the heterologous expression of SUTs and does not take up esculin. Results When type I sucrose transporters StSUT1 from potato or AtSUC2 from Arabidopsis were expressed in yeast, the cells were able to take up esculin and became brightly fluorescent. We tested a variety of incubation times, esculin concentrations, and buffer pH values and found that for these transporters, a 1 hr incubation at 0.1 to 1 mM esculin at pH 4.0 produced fluorescent cells that were easily distinguished from vector controls. Esculin uptake was assayed by several methods including fluorescence microscopy, spectrofluorometry and fluorescence-activiated cell sorting (FACS. Expression of the type II sucrose transporter OsSUT1 from rice did not result in increased esculin uptake under any conditions tested. Results were reproduced successfully in two distinct yeast strains, SEY6210 (an invertase mutant and BY4742. Conclusions The esculin uptake assay is rapid and sensitive and should be generally useful for preliminary tests of sucrose transporter function by heterologous expression in yeast. This assay is also suitable for selection of yeast showing esculin uptake activity using FACS.

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

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    Zheng, Yi; Anderson, Spencer; Zhang, Yanfeng; Garavito, R. Michael (MSU); (NWU)

    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.

  8. Additional synthesis of starch from sucrose in leaves of arabidopsis in the light

    International Nuclear Information System (INIS)

    Full text: Accumulating during daytime starch is converted in the night into sucrose and consumed in respiratory, biosynthetic and transport processes. However in the light the degradation and conversion of starch are blocked. In pulse chase experiments with wild type plants and starchless mutants pgm or adg1 of arabidopsis an increase of starch radioactivity during chase in nonradioactive medium in the light was detected. These findings suggest that starch was additionally synthesized from labeled cytosolic soluble photosynthates, preferentially from sucrose. Radiogasometric studies of gas exchange have revealed that sucrose is consumed also in photorespiratory decarboxylations. To be involved in photorespiration the products of sucrose degradation must be transported from cytosol into chloroplast. We presume that derived from sucrose hexoses are transported into chloroplast by hexose transporter and phosphorylated there in hexokinase reaction. The phosphorylated hexoses may be consumed either for additional synthesis of starch or incorporated into the reductive pentose phosphate cycle and, via this cycle, into the glycolate cycle. (author)

  9. The role of sugars and sugar metabolism genes (sucrose synthase) in arabidopsis thaliana seed development

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    Odunlami, Benjamin Oladipo

    2009-01-01

    Seed development in Arabidopsis thaliana, has been studied at several levels. However, little has been done to study the role of sugar metabolism genes in seed pod development in this species. As the fertilized egg progresses to a mature seed, the sugars composition during different stages of the developing changes. These changes are related to metabolic processes in the developing seeds, but also to the activity of sucrose- converting and transporting genes, active at the interphase between ...

  10. Plant Sucrose Transporters from a Biophysical Point of View

    Institute of Scientific and Technical Information of China (English)

    Dietmar Geiger

    2011-01-01

    T The majority of higher plants use sucrose as their main mobile carbohydrate. Proton-driven sucrose transporters play a crucial role in cell-to-cell and long-distance distribution of sucrose throughout the plant. A very negative plant membrane potential and the ability of sucrose transporters to accumulate sucrose concentrations of more than 1 M indicate that plants evolved transporters with unique structural and functional features. The knowledge about the transport mechanism and structural/functional domains of these nano-machines is, however, still fragmentary. In this review,the current knowledge about the biophysical properties of plant sucrose transporters is summarized and discussed.

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

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    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

  12. Aspects of sucrose transport in stem parenchyma of sweet sorghum

    International Nuclear Information System (INIS)

    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. 14C-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 14C 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 14C-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

  13. Sucrose amendment enhances phytoaccumulation of the herbicide atrazine in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana (thale cress or mustard weed) seedlings, under conditions of in vitro culture, a high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors. This tolerance was associated with root-to-shoot transfer and accumulation of atrazine in shoots, which resulted in significant decrease of herbicide levels in the growth medium. In soil microcosms, application of exogenous sucrose was found to confer tolerance and capacity to accumulate atrazine in Arabidopsis thaliana plants grown on atrazine-contaminated soil, and resulted in enhanced decontamination of the soil. Application of sucrose to plants grown on herbicide-polluted soil, which increases plant tolerance and xenobiotic absorption, thus appears to be potentially useful for phytoremediation. - Exogenous sucrose treatment induces plant tolerance to photosystem-targeted herbicides and enhances phytoremediation of herbicide-polluted soil

  14. Impact of sucrose transporters on fungal carbon nutrition in ectomycorrhiza

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    Tegler, Mandy

    2013-01-01

    The ectomycorrhizal symbiosis enables forest ecosystems to cover about 30 % of the Earth s terrestrial surface. In this symbiosis the fungus gets easily degradable plant derived carbohydrates in exchange for nutrients. Sucrose transporters (SUTs) were long time favored to mediate sucrose efflux at the functional interface. In this work selected SUTs of Populus trichocarpa × P. deltoides were analyzed using gene expression analyses and heterologous expression in Saccharomyces cerevisiae. Manip...

  15. Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

    International Nuclear Information System (INIS)

    Plant root growth is known to be influenced by higher levels of atmospheric carbon dioxide (CO2). Roots of some species grown in hydroponics under elevated CO2 concentrations may be more competitive sinks for photosynthetic assimilates than roots grown under lower CO2 conditions. Root branching patterns may also be influenced by elevated CO2 concentrations. Studies have also shown that factors such as soil compaction, salinity and the availability of nitrate, phosphorous, oxygen and water also influence root growth, and the effects of higher CO2 on roots can be confounded by such environmental factors. This study evaluated the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root growth, morphology, and architecture. Both ambient and elevated CO2 levels were used along with various sucrose concentrations. The study revealed that A. thaliana plants grown on a phytagar medium in small chambers with elevated CO2 had longer roots, more lateral root growth than plants grown in ambient CO2. Roots in elevated CO2 were found to have wider root diameters, and more secondary growth. The addition of sucrose to the media closely resembled the effects of elevated CO2. In addition, the increase in sucrose concentration had a bigger effect on root morphology under ambient, than elevated CO2. Therefore, both elevated CO2 and increased sucrose concentrations promote root growth by increasing their number, length, and diameter. The dichotomy branching index (DBI) also dropped resulting in a more dichotomous branching pattern. 34 refs., 5 figs

  16. Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

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    Lee-Ho, E.; Walton, L.J.; Reid, D.M.; Yeung, E.C.; Kurepin, L.V. [Calgary Univ., AB (Canada). Dept. of Biology

    2007-03-15

    Plant root growth is known to be influenced by higher levels of atmospheric carbon dioxide (CO{sub 2}). Roots of some species grown in hydroponics under elevated CO{sub 2} concentrations may be more competitive sinks for photosynthetic assimilates than roots grown under lower CO{sub 2} conditions. Root branching patterns may also be influenced by elevated CO{sub 2} concentrations. Studies have also shown that factors such as soil compaction, salinity and the availability of nitrate, phosphorous, oxygen and water also influence root growth, and the effects of higher CO{sub 2} on roots can be confounded by such environmental factors. This study evaluated the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root growth, morphology, and architecture. Both ambient and elevated CO{sub 2} levels were used along with various sucrose concentrations. The study revealed that A. thaliana plants grown on a phytagar medium in small chambers with elevated CO{sub 2} had longer roots, more lateral root growth than plants grown in ambient CO{sub 2}. Roots in elevated CO{sub 2} were found to have wider root diameters, and more secondary growth. The addition of sucrose to the media closely resembled the effects of elevated CO{sub 2}. In addition, the increase in sucrose concentration had a bigger effect on root morphology under ambient, than elevated CO{sub 2}. Therefore, both elevated CO{sub 2} and increased sucrose concentrations promote root growth by increasing their number, length, and diameter. The dichotomy branching index (DBI) also dropped resulting in a more dichotomous branching pattern. 34 refs., 5 figs.

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

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    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

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

    Science.gov (United States)

    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

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

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    Liping eSun

    2016-02-01

    Full Text Available 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.

  20. Arg188 in rice sucrose transporter OsSUT1 is crucial for substrate transport

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    Sun Ye

    2012-11-01

    Full Text Available Abstract Background Plant sucrose uptake transporters (SUTs are H+/sucrose symporters related to the major facilitator superfamily (MFS. SUTs are essential for plant growth but little is known about their transport mechanism. Recent work identified several conserved, charged amino acids within transmembrane spans (TMS in SUTs that are essential for transport activity. Here we further evaluated the role of one of these positions, R188 in the fourth TMS of OsSUT1, a type II SUT. Results The OsSUT1(R188K mutant, studied by expression in plants, yeast, and Xenopus oocytes, did not transport sucrose but showed a H+ leak that was blocked by sucrose. The H+ leak was also blocked by β-phenyl glucoside which is not translocated by OsSUT1. Replacing the corresponding Arg in type I and type III SUTs, AtSUC1(R163K and LjSUT4(R169K, respectively, also resulted in loss of sucrose transport activity. Fluorination at the glucosyl 3 and 4 positions of α-phenyl glucoside greatly decreased transport by wild type OsSUT1 but did not affect the ability to block H+ leak in the R188K mutant. Conclusion OsSUT1 R188 appears to be essential for sucrose translocation but not for substrate interaction that blocks H+ leak. Therefore, we propose that an additional binding site functions in the initial recognition of substrates. The corresponding Arg in type I and III SUTs are equally important. We propose that R188 interacts with glucosyl 3-OH and 4-OH during translocation.

  1. Induction of stromule formation by extracellular sucrose and glucose in epidermal leaf tissue of Arabidopsis thaliana

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    Schattat Martin

    2011-08-01

    Full Text Available Abstract Background Stromules are dynamic tubular structures emerging from the surface of plastids that are filled with stroma. Despite considerable progress in understanding the importance of certain cytoskeleton elements and motor proteins for stromule maintenance, their function within the plant cell is still unknown. It has been suggested that stromules facilitate the exchange of metabolites and/or signals between plastids and other cell compartments by increasing the cytosolically exposed plastid surface area but experimental evidence for the involvement of stromules in metabolic processes is not available. The frequent occurrence of stromules in both sink tissues and heterotrophic cell cultures suggests that the presence of carbohydrates in the extracellular space is a possible trigger of stromule formation. We have examined this hypothesis with induction experiments using the upper epidermis from rosette leaves of Arabidopsis thaliana as a model system. Results We found that the stromule frequency rises significantly if either sucrose or glucose is applied to the apoplast by vacuum infiltration. In contrast, neither fructose nor sorbitol or mannitol are capable of inducing stromule formation which rules out the hypothesis that stromule induction is merely the result of changes in the osmotic conditions. Stromule formation depends on translational activity in the cytosol, whereas protein synthesis within the plastids is not required. Lastly, stromule induction is not restricted to the plastids of the upper epidermis but is similarly observed also with chloroplasts of the palisade parenchyma. Conclusions The establishment of an experimental system allowing the reproducible induction of stromules by vacuum infiltration of leaf tissue provides a suitable tool for the systematic analysis of conditions and requirements leading to the formation of these dynamic organelle structures. The applicability of the approach is demonstrated here by

  2. Membrane-Transport Systems for Sucrose in Relation to Whole-Plant Carbon Partitioning

    Institute of Scientific and Technical Information of China (English)

    Brian G. Ayre

    2011-01-01

    T Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition and contribute to plant vigor by controlling source/sink relationships and biomass partitioning. Sucrose is synthesized in the cytoplasm and may move cell to cell through plasmodesmata or may cross membranes to be compartmentalized or exported to the apoplasm for uptake into adjacent cells. As a relatively large polar compound, sucrose requires proteins to facilitate efficient membrane transport. Transport across the tonoplast by facilitated diffusion, antiport with protons, and symport with protons have been proposed; for transport across plasma membranes, symport with protons and a mechanism resembling facilitated diffusion are evident. Despite decades of research, only symport with protons is well established at the molecular level. This review aims to integrate recent and older studies on sucrose flux across membranes with principles of whole-plant carbon partitioning.

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

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    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. PMID:25699973

  4. Transport of sucrose, not hexose, in the phloem

    OpenAIRE

    Liu, David D.; Chao, Wesley M.; Turgeon, Robert

    2012-01-01

    Several lines of evidence indicate that glucose and fructose are essentially absent in mobile phloem sap. However, this paradigm has been called into question, especially but not entirely, with respect to species in the Ranunculaceae and Papaveraceae. In the experiments in question, phloem sap was obtained by detaching leaves and placing the cut ends of the petioles in an EDTA solution. More hexose than sucrose was detected. In the present study, these results were confirmed for four species....

  5. Expression of peach sucrose transporters in heterologous systems points out their different physiological role.

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    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

  6. Proton-associated sucrose transport of mammalian solute carrier family 45: an analysis in Saccharomyces cerevisiae.

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    Bartölke, Rabea; Heinisch, Jürgen J; Wieczorek, Helmut; Vitavska, Olga

    2014-12-01

    The members of the solute carrier 45 (SLC45) family have been implicated in the regulation of glucose homoeostasis in the brain (SLC45A1), with skin and hair pigmentation (SLC45A2), and with prostate cancer and myelination (SLC45A3). However, apart from SLC45A1, a proton-associated glucose transporter, the function of these proteins is still largely unknown, although sequence similarities to plant sucrose transporters mark them as a putative sucrose transporter family. Heterologous expression of the three members SLC45A2, SLC45A3 and SLC45A4 in Saccharomyces cerevisiae confirmed that they are indeed sucrose transporters. [(14)C]Sucrose-uptake measurements revealed intermediate transport affinities with Km values of approximately 5 mM. Transport activities were best under slightly acidic conditions and were inhibited by the protonophore carbonyl cyanide m-chlorophenylhydrazone, demonstrating an H(+)-coupled transport mechanism. Na(+), on the other hand, had no effect on sucrose transport. Competitive inhibition assays indicated a possible transport also of glucose and fructose. Real-time PCR of mouse tissues confirmed mRNA expression of SLC45A2 in eyes and skin and of SLC45A3 primarily in the prostate, but also in other tissues, whereas SLC45A4 showed a predominantly ubiquitous expression. Altogether the results provide new insights into the physiological significance of SLC45 family members and challenge existing concepts of mammalian sugar transport, as they (i) transport a disaccharide, and (ii) perform secondary active transport in a proton-dependent manner. PMID:25164149

  7. Sucrose transport and phloem unloading in peach fruit: potential role of two transporters localized in different cell types.

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    Zanon, Laura; Falchi, Rachele; Santi, Simonetta; Vizzotto, Giannina

    2015-06-01

    Several complex physiological processes, which include long-distance translocation in the phloem and unloading in sink tissues, govern the partitioning of sugars in economically important organs, such as peach fruit. In this study, we took advantage of a symplastic tracer, carboxyfluorescein (CF), providing evidence for an apoplastic sucrose transfer in the early (SI) and middle (SIII) phases of peach fruit development. Moreover, using a combination of in situ hybridization and laser microdissection-assisted expression analysis, three putative sucrose transporters encoding genes (PpSUT1, PpSUT2, PpSUT4) were transcriptionally analyzed to relate their expression with sucrose storage in this organ. Our study revealed that PpSUT2 and PpSUT4 are the genes predominantly expressed in fruit flesh, and the detailed analysis of their expression pattern in the different cell types enabled us to suggest a specialized role in sucrose distribution. Both PpSUTs transporters could be involved in the retrieval of sucrose lost from the symplastic continuum of the phloem and, when expressed in parenchyma cells, they could be active in the import of sucrose into sink tissues, via symport from the apoplast. An alternative hypothesis has been proposed and discussed for PpSUT4 because of its putative tonoplastic localization. Taken together, our results provide new insights into the molecular mechanisms underpinning sucrose unloading and accumulation in peach fruit. PMID:25348206

  8. Arabidopsis POLYOL TRANSPORTER5, a new member of the monosaccharide transporter-like superfamily, mediates H+-Symport of numerous substrates, including myo-inositol, glycerol, and ribose.

    Science.gov (United States)

    Klepek, Yvonne-Simone; Geiger, Dietmar; Stadler, Ruth; Klebl, Franz; Landouar-Arsivaud, Lucie; Lemoine, Rémi; Hedrich, Rainer; Sauer, Norbert

    2005-01-01

    Six genes of the Arabidopsis thaliana monosaccharide transporter-like (MST-like) superfamily share significant homology with polyol transporter genes previously identified in plants translocating polyols (mannitol or sorbitol) in their phloem (celery [Apium graveolens], common plantain [Plantago major], or sour cherry [Prunus cerasus]). The physiological role and the functional properties of this group of proteins were unclear in Arabidopsis, which translocates sucrose and small amounts of raffinose rather than polyols. Here, we describe POLYOL TRANSPORTER5 (AtPLT5), the first member of this subgroup of Arabidopsis MST-like transporters. Transient expression of an AtPLT5-green fluorescent protein fusion in plant cells and functional analyses of the AtPLT5 protein in yeast and Xenopus oocytes demonstrate that AtPLT5 is located in the plasma membrane and characterize this protein as a broad-spectrum H+-symporter for linear polyols, such as sorbitol, xylitol, erythritol, or glycerol. Unexpectedly, however, AtPLT5 catalyzes also the transport of the cyclic polyol myo-inositol and of different hexoses and pentoses, including ribose, a sugar that is not transported by any of the previously characterized plant sugar transporters. RT-PCR analyses and AtPLT5 promoter-reporter gene plants revealed that AtPLT5 is most strongly expressed in Arabidopsis roots, but also in the vascular tissue of leaves and in specific floral organs. The potential physiological role of AtPLT5 is discussed. PMID:15598803

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

    Science.gov (United States)

    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. PMID:26022258

  10. Phosphoproteomic identification of targets of the Arabidopsis sucrose nonfermenting-like kinase SnRK2.8 reveals a connection to metabolic processes

    OpenAIRE

    Shin, Ryoung; Alvarez, Sophie; Burch, Adrien Y.; Jez, Joseph M.; Schachtman, Daniel P.

    2007-01-01

    SnRK2.8 is a member of the sucrose nonfermenting-related kinase family that is down-regulated when plants are deprived of nutrients and growth is reduced. When this kinase is over expressed in Arabidopsis, the plants grow larger. To understand how this kinase modulates growth, we identified some of the proteins that are phosphorylated by this kinase. A new phosphoproteomic method was used in which total protein from plants overexpressing the kinase was compared with total protein from plants ...

  11. Investigating polymorphisms in membrane-associated transporter protein SLC45A2, using sucrose transporters as a model.

    Science.gov (United States)

    Reinders, Anke; Ward, John M

    2015-07-01

    Solute carrier family 45 member 2 encodes the melanosomal membrane protein, membrane-associated transporter protein (MATP), of unknown function, that is required for normal melanin synthesis. The present study analyzed the effects of two human MATP mutations, D93N, which causes oculocutaneous albinism 4 (OCA4), and L374F, which is correlated with light pigmentation in European populations. Corresponding mutations were produced in the related and well-characterized sucrose transporter from rice, OsSUT1, and transport activity was measured by heterologous expression in Xenopus laevis oocytes, in addition to 14C-sucrose uptake in yeast. The mutation corresponding to D93N resulted in a complete loss of transport activity. The mutation corresponding to L374F resulted in a 90% decrease in transport activity, although the substrate affinity was unaffected. The results indicated that the D93N mutation causes OCA4 as a result of loss of MATP transport activity, and that the F374 allele confers significantly lower transport activity than L374. PMID:25760657

  12. Identification of mitochondrial coenzyme a transporters from maize and Arabidopsis.

    Science.gov (United States)

    Zallot, Rémi; Agrimi, Gennaro; Lerma-Ortiz, Claudia; Teresinski, Howard J; Frelin, Océane; Ellens, Kenneth W; Castegna, Alessandra; Russo, Annamaria; de Crécy-Lagard, Valérie; Mullen, Robert T; Palmieri, Ferdinando; Hanson, Andrew D

    2013-06-01

    Plants make coenzyme A (CoA) in the cytoplasm but use it for reactions in mitochondria, chloroplasts, and peroxisomes, implying that these organelles have CoA transporters. A plant peroxisomal CoA transporter is already known, but plant mitochondrial or chloroplastic CoA transporters are not. Mitochondrial CoA transporters belonging to the mitochondrial carrier family, however, have been identified in yeast (Saccharomyces cerevisiae; Leu-5p) and mammals (SLC25A42). Comparative genomic analysis indicated that angiosperms have two distinct homologs of these mitochondrial CoA transporters, whereas nonflowering plants have only one. The homologs from maize (Zea mays; GRMZM2G161299 and GRMZM2G420119) and Arabidopsis (Arabidopsis thaliana; At1g14560 and At4g26180) all complemented the growth defect of the yeast leu5Δ mitochondrial CoA carrier mutant and substantially restored its mitochondrial CoA level, confirming that these proteins have CoA transport activity. Dual-import assays with purified pea (Pisum sativum) mitochondria and chloroplasts, and subcellular localization of green fluorescent protein fusions in transiently transformed tobacco (Nicotiana tabacum) Bright Yellow-2 cells, showed that the maize and Arabidopsis proteins are targeted to mitochondria. Consistent with the ubiquitous importance of CoA, the maize and Arabidopsis mitochondrial CoA transporter genes are expressed at similar levels throughout the plant. These data show that representatives of both monocotyledons and eudicotyledons have twin, mitochondrially located mitochondrial carrier family carriers for CoA. The highly conserved nature of these carriers makes possible their reliable annotation in other angiosperm genomes. PMID:23590975

  13. Cloning and expression of the sucrose transporter gene PsSUT1 from tree peony leaf.

    Science.gov (United States)

    Li, Y H; Guo, T; Cui, Y; Li, Y; He, D

    2015-01-01

    This study reports the cloning of a sucrose transporter gene, PsSUT1, from the leaf of tree peony (Paeonia suffruticosa Lind. cv 'Huhong'). Expression patterns were examined in different organs and at different developmental stages. The full-length cDNA of PsSUT1 consisted of a 2001-bp sequence containing a 1557-bp open reading frame, encoding 519 amino acids with a conserved domain typical of the glycoside-pentoside-hexuronide superfamily. The amino acid sequence of PsSUT1 in tree peony shared high homology with that of other plants. At different developmental stages, PsSUT1 was expressed in roots, stems, leaves, and petals. Its expression level in stems was 10.9-fold higher than in petals at the flowering stage. Expression of PsSUT1 at the flowering stage was highest during flower development. The significant differences in PsSUT1 expression observed among developmental stages and organs were closely related to changes in sucrose content during flower opening. These results form the basis for further research on the molecular mechanisms of carbohydrate metabolism and transport during flower development in tree peony. PMID:26505390

  14. A vacuolar phosphate transporter essential for phosphate homeostasis in Arabidopsis

    OpenAIRE

    Liu, Jinlong; Yang, Lei; Luan, Mingda; Wang, Yuan; Zhang, Chi; Zhang, Bin; Shi, Jisen; Zhao, Fu-Geng; Lan, Wenzhi; Luan, Sheng

    2015-01-01

    Phosphate is an essential nutrient for plant growth, and inorganic phosphate (Pi) is stored largely in the vacuole of plant cells. Thus, vacuolar Pi maintains homeostasis of cytosolic Pi to ensure an optimal Pi supply for plants under variable Pi status in the soil. This study uncovered in Arabidopsis a vacuolar phosphate transporter, VPT1, that mediates vacuolar Pi sequestration. Lack of VPT1 caused growth defects under both low-Pi and high-Pi conditions, implicating VPT1 in plant adaptation...

  15. Decrease in Leaf Sucrose Synthesis Leads to Increased Leaf Starch Turnover and Decreased RuBP-limited Photosynthesis But Not Rubisco-limited Photosynthesis in Arabidopsis Null Mutants of SPSA1

    Science.gov (United States)

    SPS (Sucrose phosphate synthase) isoforms from dicots cluster into families A, B and C. In this study, we investigated the individual effect of null mutations of each of the four SPS genes in Arabidopsis (spsa1, spsa2, spsb and spsc) on photosynthesis and carbon partitioning. Null mutants spsa1 and ...

  16. MtSWEET11, a Nodule-Specific Sucrose Transporter of Medicago truncatula.

    Science.gov (United States)

    Kryvoruchko, Igor S; Sinharoy, Senjuti; Torres-Jerez, Ivone; Sosso, Davide; Pislariu, Catalina I; Guan, Dian; Murray, Jeremy; Benedito, Vagner A; Frommer, Wolf B; Udvardi, Michael K

    2016-05-01

    Optimization of nitrogen fixation by rhizobia in legumes is a key area of research for sustainable agriculture. Symbiotic nitrogen fixation (SNF) occurs in specialized organs called nodules and depends on a steady supply of carbon to both plant and bacterial cells. Here we report the functional characterization of a nodule-specific Suc transporter, MtSWEET11 from Medicago truncatula MtSWEET11 belongs to a clade of plant SWEET proteins that are capable of transporting Suc and play critical roles in pathogen susceptibility. When expressed in mammalian cells, MtSWEET11 transported sucrose (Suc) but not glucose (Glc). The MtSWEET11 gene was found to be expressed in infected root hair cells, and in the meristem, invasion zone, and vasculature of nodules. Expression of an MtSWEET11-GFP fusion protein in nodules resulted in green fluorescence associated with the plasma membrane of uninfected cells and infection thread and symbiosome membranes of infected cells. Two independent Tnt1-insertion sweet11 mutants were uncompromised in SNF Therefore, although MtSWEET11 appears to be involved in Suc distribution within nodules, it is not crucial for SNF, probably because other Suc transporters can fulfill its role(s). PMID:27021190

  17. Bayesian phylogeny of sucrose transporters: Ancient origins, differential expansion and convergent evolution in monocots and dicots

    Directory of Open Access Journals (Sweden)

    Duo ePeng

    2014-11-01

    Full Text Available Sucrose transporters (SUTs are essential for the export and efficient movement of sucrose from source leaves to sink organs in plants. The angiosperm SUT family was previously classified into three or four distinct groups, Types I, II (subgroup IIB and III, with dicot-specific Type I and monocot-specific Type IIB functioning in phloem loading. To shed light on the underlying drivers of SUT evolution, Bayesian phylogenetic inference was undertaken using 41 sequenced plant genomes, including seven basal lineages at key evolutionary junctures. Our analysis supports four phylogenetically and structurally distinct SUT subfamilies, originating from two ancient groups (AG1 and AG2 that diverged early during terrestrial colonization. In both AG1 and AG2, multiple intron acquisition events in the progenitor vascular plant established the gene structures of modern SUTs. Tonoplastic Type III and plasmalemmal Type II represent evolutionarily conserved descendants of AG1 and AG2, respectively. Type I and Type IIB were previously thought to evolve after the dicot-monocot split. We show, however, that divergence of Type I from Type III SUT predated basal angiosperms, likely associated with evolution of vascular cambium and phloem transport. Type I SUT was subsequently lost in monocots along with vascular cambium, and independent evolution of Type IIB coincided with modified monocot vasculature. Both Type I and Type IIB underwent lineage-specific expansion. In multiple unrelated taxa, the newly-derived SUTs exhibit biased expression in reproductive tissues, suggesting a functional link between phloem loading and reproductive fitness. Convergent evolution of Type I and Type IIB for SUT function in phloem loading and reproductive organs supports the idea that differential vascular development in dicots and monocots is a strong driver for SUT family evolution in angiosperms.

  18. The Arabidopsis NPF3 protein is a GA transporter

    DEFF Research Database (Denmark)

    Tal, Iris; Zhang, Yi; Jørgensen, Morten Egevang; Pisanty, Odelia; Barbosa, Inês C R; Zourelidou, Melina; Regnault, Thomas; Crocoll, Christoph; Erik Olsen, Carl; Weinstain, Roy; Schwechheimer, Claus; Halkier, Barbara Ann; Nour-Eldin, Hussam Hassan; Estelle, Mark; Shani, Eilon

    2016-01-01

    deficient in GA transport. We show that the NPF3 transporter efficiently transports GA across cell membranes in vitro and GA-Fl in vivo. NPF3 is expressed in root endodermis and repressed by GA. NPF3 is targeted to the plasma membrane and subject to rapid BFA-dependent recycling. We show that abscisic acid...... (ABA), an antagonist of GA, is also transported by NPF3 in vitro. ABA promotes NPF3 expression and GA-Fl uptake in plants. On the basis of these results, we propose that GA distribution and activity in Arabidopsis is partly regulated by NPF3 acting as an influx carrier and that GA-ABA interaction may...

  19. Anthocyanin Biosynthesis Regulated by Sucrose in Arabidopsis thaliana Seedling%蔗糖调节拟南芥花青素的生物合成

    Institute of Scientific and Technical Information of China (English)

    杨少华; 王丽; 穆春; 王翔; 何静辉; 赵静尧; 王林嵩

    2011-01-01

    为了探讨糖在花青素合成过程中的调节作用,采用蔗糖和其代谢糖(葡萄糖和果糖)组合处理拟南芥幼苗.实验结果表明,60 mmol/L蔗糖处理显著提高拟南芥幼苗的花青素、还原糖含量,并上调花青素合成相关基因(CHS,FLS-1,DFR,LDOX,BANYULS)的转录,对叶绿素含量和UGT78D2基因的转录无影响;20 mmol/L葡萄糖+20 mmol/L果糖处理,对花青素、叶绿素和还原糖的含量无影响,对花青素合成相关基因转录影响不一;20 mmol/L蔗糖+20 mmol/L葡萄糖+20mmol/L果糖处理后,花青素和还原糖含量介于前两个处理之间,也上调花青素合成相关基因的转录;但和蔗糖处理组相比,上调UG778D2基因转录,下调FLS-1基因转录.在不同处理组之间,花青素含量变化和还原糖含量变化趋势相同,有可能糖在调节花青素合成的同时也调节还原糖含量.因此,蔗糖既可以通过蔗糖特异信号途径,也可以和其代谢糖通过其他途径共同调节拟南芥花青素的生物合成.%In order to investigate the sugar regulation of anthocyanin biosynthesis, the combined effects of sucrose and its metabolic product of glucose and fructose were studied in Arabidopsis thaliana seedling.The results indicated that when cultured with 60 mmol/L sucrose, the contents of anthocyanin and reductive sugars were significantly increased, and the transcription genes in anthocyanin biosynthesis were upregulated, such as chalcone synthase (CHS) , flavonol synthase-1 (FLS-1) , dihydroflavonol reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), anthocyanidin reductase (BANYULS).The chlorophyll content and UDP-Glc: flavonoid 3-O-glucosyltransferase (UGT78D2) expression remained unchanged.When grown at 1∶1 mixture of 20 mmol/L glucose + 20 mmol/L fructose, no changes of anthocyanin, chlorophyll and reductive sugars were observed, whereas the expression of anthocyanin biosynthetic genes varied.In case of the treatment with 1∶ 1∶ 1 mixture of

  20. Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Scott A. [Univ. of Georgia, Athens, GA (United States); Tsai, Chung-Jui [Univ. of Georgia, Athens, GA (United States)

    2016-01-04

    The overall project objective was to probe the relationship between sucrose transporters and plant productivity in the biomass for biofuels woody perennial, Populus. At the time the proposal was written, sucrose transporters had already been investigated in many plant model systems, primarily with respect to the export of photosynthate sucrose from source leaves, and the uptake of sucrose in storage organs and seeds. Preliminary findings by the PI found that in Populus, sucrose transporter genes (SUTs) were well expressed in wood-forming tissues that comprise the feedstock for biofuels production. Because sucrose comprises by far the predominant form in which photosynthate is delivered from source organs to sink organs like roots and wood-forming tissues, SUTs control a gate that nominally at least could impact the allocation or partitioning of sucrose for potentially competing end uses like growth (stem biomass) and storage. In addition, water use might be conditioned by the way in which sucrose is distributed throughout the plant, and/or by the way in which sucrose is partitioned intracellularly. Several dozen transgenic lines were produced in year 1 of the project to perturb the expression ratio of multiple plasma membrane (PM) SUTs (intercellular trafficking), versus the single tonoplast membrane (TM) sucrose transporter that effectively regulates intracellular trafficking of sucrose. It was possible to obtain transgenic lines with dual SUT gene knockdown using the 35S promoter, but not the wood-specific TUA1 promoter. By the end of project year 2, a decision was made to work with the 35S plants while archiving the TUA1 plants. The PhD candidate charged with producing the transgenic lines abandoned the project during its second year, substantially contributing to the decision to operate with just the 35S lines. That student’s interests ranged more toward evolutionary topics, and a report on SUT gene evolution was published (Peng et al 2014).

  1. Fusion to GFP blocks intercellular trafficking of the sucrose transporter SUT1 leading to accumulation in companion cells

    Directory of Open Access Journals (Sweden)

    Walsh Rama

    2003-12-01

    Full Text Available Abstract Background Plant phloem consists of an interdependent cell pair, the sieve element / companion cell complex. Sucrose transporters are localized to enucleate sieve elements (SE, despite being transcribed in companion cells (CC. Due to the high turnover of SUT1, sucrose transporter mRNA or protein must traffic from CC to SE via the plasmodesmata. Localization of SUT mRNA at plasmodesmatal orifices connecting CC and SE suggests RNA transport, potentially mediated by RNA binding proteins. In many organisms, polar RNA transport is mediated through RNA binding proteins interacting with the 3'-UTR and controlling localized protein synthesis. To study mechanisms for trafficking of SUT1, GFP-fusions with and without 3'-UTR were expressed in transgenic plants. Results In contrast to plants expressing GFP from the strong SUC2 promoter, in RolC-controlled expression GFP is retained in companion cells. The 3'-UTR of SUT1 affected intracellular distribution of GFP but was insufficient for trafficking of SUT1, GFP or their fusions to SEs. Fusion of GFP to SUT1 did however lead to accumulation of SUT1-GFP in the CC, indicating that trafficking was blocked while translational inhibition of SUT1 mRNA was released in CCs. Conclusion A fusion with GFP prevents targeting of the sucrose transporter SUT1 to the SE while leading to accumulation in the CC. The 3'-UTR of SUT1 is insufficient for mobilization of either the fusion or GFP alone. It is conceivable that SUT1-GFP protein transport through PD to SE was blocked due to the presence of GFP, resulting in retention in CC particles. Alternatively, SUT1 mRNA transport through the PD could have been blocked due to insertion of GFP between the SUT1 coding sequence and 3'-UTR.

  2. A Mitochondrial Magnesium Transporter Functions in Arabidopsis Pollen Development

    Institute of Scientific and Technical Information of China (English)

    Le-Gong Li; Lubomir N.Sokolov; Yong-Hua Yang; Dong-Ping Li; Julie Ting; Girdhar K.Pandy; Sheng Luan

    2008-01-01

    Magnesium is an abundant divalent cation in plant cells and plays a critical role in many physiological processes.We have previously described the jdentification of a 10-member Arabidopsis gene family encoding putative magnesium transport(MGT)proteins.Here,we report that a member of the MGT family,AtMGT5, functions as a dual-functional Mg-transporter that operates in a concentration-dependent manner, namely it serves as a Mg-importer at micromolar levels and facilitates the efflux in the millimolar range.The AtMGT5 protein is localized in the mitochondria,suggesting that AtMGT5 mediates Mg-trafficking between the cytosol and mitochondria.The AtMGT5 gene was exclusively expressed in anthers at early stages of flower development.Examination of two independent T-DNA insertional mutants of AtMGT5 gene demonstrated that AtMG7-5 played an essential role for pollen development and male fertility.This study suggests a critical role for Mg2+ transport between cytosol and mitochondria in male gametogenesis in plants.

  3. A subgroup of MATE transporter genes regulates hypocotyl cell elongation in Arabidopsis.

    Science.gov (United States)

    Wang, Rui; Liu, Xiayan; Liang, Shuang; Ge, Qing; Li, Yuanfeng; Shao, Jingxia; Qi, Yafei; An, Lijun; Yu, Fei

    2015-10-01

    The growth of higher plants is under complex regulation to ensure the elaboration of developmental programmes under a changing environment. To dissect these regulatory circuits, we carried out genetic screens for Arabidopsis abnormal shoot (abs) mutants with altered shoot development. Here, we report the isolation of two dominant mutants, abs3-1D and abs4-1D, through activation tagging. Both mutants showed a 'bushy' loss of apical dominance phenotype. ABS3 and ABS4 code for two closely related putative Multidrug and Toxic Compound Extrusion (MATE) family of efflux transporters, respectively. ABS3 and ABS4, as well as two related MATE genes, ABS3-Like1 (ABS3L1) and ABS3L2, showed diverse tissue expression profiles but their gene products all localized to the late endosome/prevacuole (LE/PVC) compartment. The over-expression of these four genes individually led to the inhibition of hypocotyl cell elongation in the light. On the other hand, the quadruple knockout mutant (mateq) showed the opposite phenotype of an enhanced hypocotyl cell elongation in the light. Hypocotyl cell elongation and de-etiolation processes in the dark were also affected by the mutations of these genes. Exogenously applied sucrose attenuated the inhibition of hypocotyl elongation caused by abs3-1D and abs4-1D in the dark, and enhanced the hypocotyl elongation of mateq under prolonged dark treatment. We determined that ABS3 genetically interacts with the photoreceptor gene PHYTOCHROME B (PHYB). Our results demonstrate that ABS3 and related MATE family transporters are potential negative regulators of hypocotyl cell elongation and support a functional link between the endomembrane system, particularly the LE/PVC, and the regulation of plant cell elongation. PMID:26160579

  4. Auxin polar transport in arabidopsis under simulated microgravity conditions - relevance to growth and development

    Science.gov (United States)

    Miyamoto, K.; Oka, M.; Yamamoto, R.; Masuda, Y.; Hoson, T.; Kamisaka, S.; Ueda, J.

    1999-01-01

    Activity of auxin polar transport in inflorescence axes of Arabidopsis thaliana grown under simulated microgravity conditions was studied in relation to the growth and development. Seeds were germinated and allowed to grow on an agar medium in test tubes on a horizontal clinostat. Horizontal clinostat rotation substantially reduced the growth of inflorescence axes and the productivity of seeds of Arabidopsis thaliana (ecotypes Landsberg erecta and Columbia), although it little affected seed germination, development of rosette leaves and flowering. The activity of auxin polar transport in inflorescence axes decreased when Arabidopsis plants were grown on a horizontal clinostat from germination stage, being ca. 60% of 1 g control. On the other hand, the auxin polar transport in inflorescence axes of Arabidopsis grown in 1 g conditions was not affected when the segments were exposed to various gravistimuli, including 3-dimensional clinorotation, during transport experiments. Pin-formed mutant of Arabidopsis, having a unique structure of the inflorescence axis with no flower and extremely low levels of the activity of auxin polar transport in inflorescence axes and endogenous auxin, did not continue its vegetative growth under clinostat rotation. These facts suggest that the development of the system of auxin polar transport in Arabidopsis is affected by microgravity, resulting in the inhibition of growth and development, especially during reproductive growth.

  5. Auxin transport in an auxin-resistant mutant of arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Lincoln, C.; Benning, C.; Estelle, M.

    1987-04-01

    The authors are studying a group of allelic recessive mutations in Arabidopsis called axr-1. Homozygous axr-1 plants are resistant to exogenously applied auxin. In addition, axr-1 mutations all confer a number of development abnormalities including an apparent reduction in apical dominance, loss of normal geotropic response, and a failure to self-fertilize due to a decrease in stamen elongation. In order to determine whether this pleiotropic phenotype is due to an alteration in auxin transport they have adapted the agar block transport assay for use in Arabidopsis stem segments. Their results indicate that as in other plant species, auxin transport is strongly polar in Arabidopsis stem segments. In addition transport is inhibited by the well characterized auxin transport inhibitor N-1-naphthylphthalamic acid and the artificial auxin 2,4-D. These results as well as the characterization of transport in axr-1 plants will be presented.

  6. The Tonoplast-Localized Sucrose Transporter in Populus (PtaSUT4) Regulates Whole-Plant Water Relations, Responses to Water Stress, and Photosynthesis

    OpenAIRE

    Frost, Christopher J; Nyamdari, Batbayar; Tsai, Chung-Jui; Harding, Scott A.

    2012-01-01

    The Populus sucrose (Suc) transporter 4 (PtaSUT4), like its orthologs in other plant taxa, is tonoplast localized and thought to mediate Suc export from the vacuole into the cytosol. In source leaves of Populus, SUT4 is the predominantly expressed gene family member, with transcript levels several times higher than those of plasma membrane SUTs. A hypothesis is advanced that SUT4-mediated tonoplast sucrose fluxes contribute to the regulation of osmotic gradients between cellular compartments,...

  7. Arabidopsis flower development-of protein complexes, targets, and transport.

    Science.gov (United States)

    Becker, Annette; Ehlers, Katrin

    2016-03-01

    Tremendous progress has been achieved over the past 25 years or more of research on the molecular mechanisms of floral organ identity, patterning, and development. While collections of floral homeotic mutants of Antirrhinum majus laid the foundation already at the beginning of the previous century, it was the genetic analysis of these mutants in A. majus and Arabidopsis thaliana that led to the development of the ABC model of floral organ identity more than 20 years ago. This intuitive model kick-started research focused on the genetic mechanisms regulating flower development, using mainly A. thaliana as a model plant. In recent years, interactions among floral homeotic proteins have been elucidated, and their direct and indirect target genes are known to a large extent. Here, we provide an overview over the advances in understanding the molecular mechanism orchestrating A. thaliana flower development. We focus on floral homeotic protein complexes, their target genes, evidence for their transport in floral primordia, and how these new results advance our view on the processes downstream of floral organ identity, such as organ boundary formation or floral organ patterning. PMID:25845756

  8. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    OpenAIRE

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M.; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L.

    2016-01-01

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rh...

  9. The Potato Sucrose Transporter StSUT1 Interacts with a DRM-Associated Protein Disulfide Isomerase

    Institute of Scientific and Technical Information of China (English)

    Undine Krügel; Hong-Xia He; Konstanze Gier; Jana Reins; Izabela Chincinska; Bernhard Grimm; Waltraud X. Schulze; Christina Kühn

    2012-01-01

    Organization of proteins into complexes is crucial for many cellular functions.Recently,the SUT1 protein was shown to form homodimeric complexes,to be associated with lipid raft-like microdomains in yeast as well as in plants and to undergo endocytosis in response to brefeldin A.We therefore aimed to identify SUT1-interacting proteins that might be involved in dimerization,endocytosis,or targeting of SUT1 to raft-like microdomains.Therefore,we identified potato membrane proteins,which are associated with the detergent-resistant membrane (DRM) fraction.Among the proteins identified,we clearly confirmed StSUT1 as part of DRM in potato source leaves.We used the yeast two-hybrid split ubiquitin system (SUS) to systematically screen for interaction between the sucrose transporter StSUT1 and other membraneassociated or soluble proteins in vivo.The SUS screen was followed by immunoprecipitation using affinity-purified StSUT1-specific peptide antibodies and mass spectrometric analysis of co-precipitated proteins.A large overlap was observed between the StSUT1-interacting proteins identified in the co-immunoprecipitation and the detergent-resistant membrane fraction.One of the SUT1-interacting proteins,a protein disulfide isomerase (PDI),interacts also with other sucrose transporter proteins.A potential role of the PDI as escort protein is discussed.

  10. Phosphoenolpyruvate-dependent phosphorylation of sucrose by Clostridium tyrobutyricum ZJU 8235: evidence for the phosphotransferase transport system.

    Science.gov (United States)

    Jiang, Ling; Cai, Jin; Wang, Jufang; Liang, Shizhong; Xu, Zhinan; Yang, Shang-Tian

    2010-01-01

    The uptake and metabolism of sucrose, the major sugar in industrial cane molasses, by Clostridium tyrobutyricum ZJU 8235 was investigated and this study provided the first definitive evidence for phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) activity in butyric acid-producing bacteria. Glucose was utilized preferentially to sucrose when both substrates were present in the medium. The PEP-dependent sucrose: PTS was induced by growing C. tyrobutyricum on sucrose (but not glucose) as the sole carbon source. Extract fractionation and PTS reconstitution experiments revealed that both soluble and membrane components were required for bioactivity. Sucrose-6-phosphate hydrolase and fructokinase activities were also detected in sucrose-grown cultures. Based on these findings, a pathway of sucrose metabolism in this organism was proposed that includes the forming of sucrose-6-phosphate via the PTS and its further degradation into glucose-6-phosphate and fructose-6-phosphate. PMID:19726178

  11. The Arabidopsis NPF3 protein is a GA transporter

    DEFF Research Database (Denmark)

    Tal, Iris; Zhang, Yi; Jørgensen, Morten Egevang;

    2016-01-01

    Gibberellins (GAs) are plant hormones that promote a wide range of developmental processes. While GA signalling is well understood, little is known about how GA is transported or how GA distribution is regulated. Here we utilize fluorescently labelled GAs (GA-Fl) to screen for Arabidopsis mutants...... (ABA), an antagonist of GA, is also transported by NPF3 in vitro. ABA promotes NPF3 expression and GA-Fl uptake in plants. On the basis of these results, we propose that GA distribution and activity in Arabidopsis is partly regulated by NPF3 acting as an influx carrier and that GA-ABA interaction may...

  12. Parenchymal transport of (14C)-sucrose and D-(14C)-mannitol in sugar beet roots after introduction via xylem vessels

    International Nuclear Information System (INIS)

    The transfer of (14C) sucrose and D-(14C) mannitol from the bundles to the bundle-free parenchyma regions in sugar beet roots was studied after feeding 10 mM solutions to the storage organ via xylem. Both solutes entered the bundle free parenchyma region with comparable velocities, but mannitol mainly remained in the free space during the transfer period whereas sucrose was quickly taken up by the cells near the bundles. The apoplastic transfer of mannitol indicated the absence of a barrier between the xylem vessels and the free space of storage parenchyma. Consequently, the sugar concentration cannot be much higher in the free space than in xylem exudate. Considering low extracellular sugar concentrations in situ and the finding of symplastic transport in the xylem feeding experiment it is assumed that also in natural parenchymal transport of sucrose after unloading of phloem the symplastic pathway is involved (author)

  13. PGR5-PGRL1-Dependent Cyclic Electron Transport Modulates Linear Electron Transport Rate in Arabidopsis thaliana.

    Science.gov (United States)

    Suorsa, Marjaana; Rossi, Fabio; Tadini, Luca; Labs, Mathias; Colombo, Monica; Jahns, Peter; Kater, Martin M; Leister, Dario; Finazzi, Giovanni; Aro, Eva-Mari; Barbato, Roberto; Pesaresi, Paolo

    2016-02-01

    Plants need tight regulation of photosynthetic electron transport for survival and growth under environmental and metabolic conditions. For this purpose, the linear electron transport (LET) pathway is supplemented by a number of alternative electron transfer pathways and valves. In Arabidopsis, cyclic electron transport (CET) around photosystem I (PSI), which recycles electrons from ferrodoxin to plastoquinone, is the most investigated alternative route. However, the interdependence of LET and CET and the relative importance of CET remain unclear, largely due to the difficulties in precise assessment of the contribution of CET in the presence of LET, which dominates electron flow under physiological conditions. We therefore generated Arabidopsis mutants with a minimal water-splitting activity, and thus a low rate of LET, by combining knockout mutations in PsbO1, PsbP2, PsbQ1, PsbQ2, and PsbR loci. The resulting Δ5 mutant is viable, although mature leaves contain only ∼ 20% of wild-type naturally less abundant PsbO2 protein. Δ5 plants compensate for the reduction in LET by increasing the rate of CET, and inducing a strong non-photochemical quenching (NPQ) response during dark-to-light transitions. To identify the molecular origin of such a high-capacity CET, we constructed three sextuple mutants lacking the qE component of NPQ (Δ5 npq4-1), NDH-mediated CET (Δ5 crr4-3), or PGR5-PGRL1-mediated CET (Δ5 pgr5). Their analysis revealed that PGR5-PGRL1-mediated CET plays a major role in ΔpH formation and induction of NPQ in C3 plants. Moreover, while pgr5 dies at the seedling stage under fluctuating light conditions, Δ5 pgr5 plants are able to survive, which underlines the importance of PGR5 in modulating the intersystem electron transfer. PMID:26687812

  14. Photoperiodic regulation of the sucrose transporter StSUT4 affects the expression of circadian-regulated genes and ethylene production

    Directory of Open Access Journals (Sweden)

    Izabela eChincinska

    2013-02-01

    Full Text Available Several recent publications report different subcellular localisation of members of the SUT4 subfamily of sucrose transporters. The physiological function of SUT4 sucrose transporters is still not entirely clarified as down-regulation of members of the SUT4 clade had very different effects in rice, poplar and potato. Here, we provide new data on the localization and function of the Solanaceous StSUT4 protein, further elucidating involvement in the onset of flowering, tuberization and in the shade avoidance syndrome of potato plants.Induction of early flowering and tuberization in SUT4-inhibited potato plants correlates with increased sucrose export from leaves and increased sucrose and starch accumulation in terminal sink organs such as developing tubers. SUT4 does not only affect the expression of gibberellin and ethylene biosynthetic enzymes, but also the rate of ethylene synthesis in potato. In SUT4-inhibited plants, the ethylene production no longer follows a diurnal rhythm, leading to the assumption that StSUT4 controls circadian gene expression, potentially by regulating sucrose export from leaves. Furthermore, SUT4 expression affects clock-regulated genes such as StFT, StSOC1 and StCO, which might also be involved in a photoperiod-dependently controlled tuberization. A model is proposed in which StSUT4 controls a phloem-mobile signalling molecule generated in leaves which together with enhanced sucrose export affects developmental switches in apical meristems. SUT4 seems to link photoreceptor-perceived information about the light quality and day length, with phytohormone biosynthesis and the expression of circadian genes.

  15. An Arabidopsis flavonoid transporter is required for anther dehiscence and pollen development

    OpenAIRE

    Thompson, Elinor P.; Wilkins, Christopher; Demidchik, Vadim; Davies, Julia M; Glover, Beverley J.

    2010-01-01

    FLOWER FLAVONOID TRANSPORTER (FFT) encodes a multidrug and toxin efflux family transporter in Arabidopsis thaliana. FFT (AtDTX35) is highly transcribed in floral tissues, the transcript being localized to epidermal guard cells, including those of the anthers, stigma, siliques and nectaries. Mutant analysis demonstrates that the absence of FFT transcript affects flavonoid levels in the plant and that the altered flavonoid metabolism has wide-ranging consequences. Root growth, seed development ...

  16. Aluminum-activated citrate and malate transporters from the MATE and ALMT families function independently to confer Arabidopsis aluminum tolerance

    Science.gov (United States)

    Aluminum (Al) activated root malate and citrate exudation play an important role in Al tolerance in many plant species. AtALMT1, an Al-activated malate transporter, is a major contributor to Arabidopsis Al tolerance. Here, we demonstrate that a second, unrelated gene, AtMATE, encodes an Arabidopsi...

  17. The Phosphate Transporter PHT4;6 Is a Determinant of Salt Tolerance that Is Localized to the Golgi Apparatus of Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Beatriz Cubero; Yuko Nakagawa; Xing-Yu jiang; Ken-Ji Miura; Fang Li; Kashchandra G.Raghothama; Ray A.Bressan; Paul M.Hasegawa; Jose M.Pardo

    2009-01-01

    Insertion mutations that disrupt the function of PHT4;6 (At5g44370) cause NaCI hypersensitivity of Arabidop-sis seedlings that is characterized by reduced growth of the primary root,enhanced lateral branching,and swelling of root tips.Mutant phenotypes were exacerbated by sucrose,but not by equiosmolar concentrations of mannitol,and atten-uated by low inorganic phosphate in the medium.Protein PHT4;6 belongs to the Major Facilitator Superfamily of per-meases that shares significant sequence similarity to mammalian type-I Pi transporters and vesicular glutamate transporters,and is a member of the PHT4 family of putative intracellular phosphate transporters of plants.PHT4;6 local-izes to the Golgi membrane and transport studies indicate that PHT4;6 facilitates the selective transport of Pi but not of chloride or inorganic anions.Phenotypic similarities with other mutants displaying root swelling suggest that PHT4;6 likely functions in protein N-glycosylation and cell wall biosynthesis,which are essential for salt tolerance.Together,our results indicate that PHT4;6 transports Pi out of the Golgi lumenal space for the re-cycling of the Pi released from glycosylation processes.

  18. Flavonoids act as negative regulators of auxin transport in vivo in arabidopsis

    Science.gov (United States)

    Brown, D. E.; Rashotte, A. M.; Murphy, A. S.; Normanly, J.; Tague, B. W.; Peer, W. A.; Taiz, L.; Muday, G. K.

    2001-01-01

    Polar transport of the plant hormone auxin controls many aspects of plant growth and development. A number of synthetic compounds have been shown to block the process of auxin transport by inhibition of the auxin efflux carrier complex. These synthetic auxin transport inhibitors may act by mimicking endogenous molecules. Flavonoids, a class of secondary plant metabolic compounds, have been suggested to be auxin transport inhibitors based on their in vitro activity. The hypothesis that flavonoids regulate auxin transport in vivo was tested in Arabidopsis by comparing wild-type (WT) and transparent testa (tt4) plants with a mutation in the gene encoding the first enzyme in flavonoid biosynthesis, chalcone synthase. In a comparison between tt4 and WT plants, phenotypic differences were observed, including three times as many secondary inflorescence stems, reduced plant height, decreased stem diameter, and increased secondary root development. Growth of WT Arabidopsis plants on naringenin, a biosynthetic precursor to those flavonoids with auxin transport inhibitor activity in vitro, leads to a reduction in root growth and gravitropism, similar to the effects of synthetic auxin transport inhibitors. Analyses of auxin transport in the inflorescence and hypocotyl of independent tt4 alleles indicate that auxin transport is elevated in plants with a tt4 mutation. In hypocotyls of tt4, this elevated transport is reversed when flavonoids are synthesized by growth of plants on the flavonoid precursor, naringenin. These results are consistent with a role for flavonoids as endogenous regulators of auxin transport.

  19. Auxin distribution and transport during embryogenesis and seed germi-nation of Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Auxin distribution during embryogenesis and seed germination were studied with transgenic Arabidopsis plants expressing GUS gene driven by a synthetic DR5 promoter, an auxin responsive promoter. The results showed that GUS activity is higher in ends of hypophysis and cotyledon primordia of heart-, torpedo- and cotyledon-stage embryos, leaf tip area, lateral root primordia, root apex and cotyledon of young seedlings.And GUS accumulated in root apex of the seedlings grown on auxin transport inhibitor containing media.All these suggested that above-mentioned part of the organs and tissues have a higher level of auxin, and auxin polar transport inhibitor could cause the accumulation of auxin in root apex. And auxin transport inhibitor also resulted in aberration of Arabidopsis leaf pattern formation, root gravitropism and elongation.

  20. Vacuolar-Iron-Transporter1-Like Proteins Mediate Iron Homeostasis in Arabidopsis

    OpenAIRE

    Gollhofer, Julia; Timofeev, Roman; LAN, PING; Schmidt, Wolfgang; Buckhout, Thomas J.

    2014-01-01

    Iron deficiency is a nutritional problem in plants and reduces crop productivity, quality and yield. With the goal of improving the iron (Fe) storage properties of plants, we have investigated the function of three Arabidopsis proteins with homology to Vacuolar Iron Transporter1 (AtVIT1). Heterologous expression of Vacuolar Iron Transporter-Like1 (AtVTL1; At1g21140), AtVTL2 (At1g76800) or AtVTL5 (At3g25190) in the yeast vacuolar Fe transport mutant, Δccc1, restored growth in the presence of 4...

  1. The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis

    DEFF Research Database (Denmark)

    Rautengarten, Carsten; Ebert, Berit; Moreno, Ignacio;

    2014-01-01

    are specifically presumed to deliver the diverse array of nucleotide sugars found in plants. This study has developed a novel approach that enabled functional characterization of six bifunctional UDP-rhamnose (Rha)/UDP-galactose (Gal) transporters from Arabidopsis. An analysis of loss-of-function and...... overexpression lines for two of these transporters identified biochemical alterations supporting their roles in the biosynthesis of Rha- and Gal-containing polysaccharides. Thus, cell wall polysaccharide biosynthesis in the Golgi apparatus of plants is likely also regulated by substrate transport mechanisms....

  2. Sucrose translocation in Pseudomonas saccharophila

    International Nuclear Information System (INIS)

    Unlike many microorganisms, P. saccharophila is capable of growth on sucrose but not on glucose or fructose without prior mutation. For the wild-type sucrose uptake into cells requires induction by substrate and this is accompanied by the appearance of a membrane-bound protein with an apparent MW of ∼ 84kDa. A constitutive, overproducer of this protein has been isolated and as expected this mutant transports sucrose in an amplified manner. Scatchard analysis of 3H-sucrose binding to cytoplasmic membranes reveals an apparent K/sub D/ of about 1.0μM for both mutant and wild-type. In contrast mutant membranes contain 5-6 times more binding sites than the wild-type membranes. 6'-deoxy-6'-(2-hydroxy-4-azido)benzamido-sucrose (6'-HABS), a sucrose analogue, has been used to identify the protein responsible for sucrose binding. When cytoplasmic membranes are irradiated in the presence of 125I-6'-HABS, a significant portion of the radioactivity is found covalently associated with the 84kDa band in SDS-PAGE. Importantly, labeling of this band is largely prevented when unlabeled sucrose is present during photolysis. The authors believe that the 84kDa protein may be a sucrose permease and efforts are underway to reconstitute it in a functional form

  3. Arabidopsis thaliana AtUTr7 Encodes a Golgi-Localized UDP-Glucose/UDP-Galactose Transporter that Affects Lateral Root Emergence

    Institute of Scientific and Technical Information of China (English)

    Michael Handford; Cecilia Rodríguez-Furlán; Lorena Marchant; Marcelo Segura; Daniela Gómez; Elena Alvarez-Buyll; Guang-Yan Xiong; Markus Pauly; Ariel Orellana

    2012-01-01

    Nucleotide sugar transporters (NSTs) are antiporters comprising a gene family that plays a fundamental role in the biosynthesis of complex cell wall polysaccharides and glycoproteins in plants.However,due to the limited number of related mutants that have observable phenotypes,the biological function(s) of most NSTs in cell wall biosynthesis and assembly have remained elusive.Here,we report the characterization of AtUTr7 from Arabidopsis (Arabidopsis thaliana (L.) Heynh.),which is homologous to multi-specific UDP-sugar transporters from Drosophila melanogaster,humans,and Caenorhabditis elegans.We show that AtUTr7 possesses the common structural characteristics conserved among NSTs.Using a green fluorescent protein (GFP) tagged version,we demonstrate that AtUTr7 is localized in the Golgi apparatus.We also show that AtUTr7 is widely expressed,especially in the roots and in specific floral organs.Additionally,the results of an in vitro nucleotide sugar transport assay carried out with a tobacco and a yeast expression system suggest that AtUTr7 is capable of transferring UDP-Gal and UDP-GIc,but not a range of other UDP-and GDP-sugars,into the Golgi lumen.Mutants lacking expression of AtUTr7 exhibited an early proliferation of lateral roots as well as distorted root hairs when cultivated at high sucrose concentrations.Furthermore,the distribution of homogalacturonan with a low degree of methyl esterification differed in lateral root tips of the mutant compared to wild-type plants,although additional analytical procedures revealed no further differences in the composition of the root cell walls.This evidence suggests that the transport of UDP-Gal and UDP-GIc into the Golgi under conditions of high root biomass production plays a role in lateral root and root hair development.

  4. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development.

    Science.gov (United States)

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L

    2016-01-01

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development. PMID:27381418

  5. From the Soil to the Seed. Metal Transport in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Guerinot, Mary Lou [Dartmouth College, Hanover, NH (United States)

    2015-02-27

    Deficiencies of micronutrients such as Fe, Mn, and Zn commonly limit plant growth and crop yields. The long-term goals of our program are to understand how plants acquire metal micronutrients from the soil and distribute them while protecting themselves from the potential redox damage metals can cause to living tissues. Metals serve as important co-factors for photosynthesis and respiration, yet we still know very little about metal transport. Our approach combines experimental and computational tools from the physical sciences with biochemistry and molecular biology. Specifically, we combine mutant analysis with synchrotron X-ray fluorescence (SXRF) spectroscopy, a technique that allows us to image the elemental composition of living plant material in 3-D. By analyzing the phenotypes of lines carrying mutations in various metal transporters, we have identified the genes responsible for uptake of zinc from the soil as well as genes involved in loading the seeds with metal micronutrients. Several of these transporters affect the localization of metals in the seed without affecting the overall metal content. Understanding how seeds obtain and store nutrients is key to developing crops with higher agronomic and nutritional value.

  6. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis

    Science.gov (United States)

    Garbers, C.; DeLong, A.; Deruere, J.; Bernasconi, P.; Soll, D.; Evans, M. L. (Principal Investigator)

    1996-01-01

    The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis.

  7. Cadmium and iron transport by members of a plant metal transporter family in Arabidopsis with homology to Nramp genes

    OpenAIRE

    Thomine, Sébastien; Wang, Rongchen; Ward, John M.; Crawford, Nigel M.; Schroeder, Julian I.

    2000-01-01

    Metal cation homeostasis is essential for plant nutrition and resistance to toxic heavy metals. Many plant metal transporters remain to be identified at the molecular level. In the present study, we have isolated AtNramp cDNAs from Arabidopsis and show that these genes complement the phenotype of a metal uptake deficient yeast strain, smf1. AtNramps show homology to the Nramp gene family in bacteria, yeast, plants, and animals. Expression of AtNramp cDNAs increases Cd2+ sensitivity and Cd2+ a...

  8. Endocytosis and degradation of BOR1, a boron transporter of Arabidopsis thaliana, regulated by boron availability

    OpenAIRE

    Takano, Junpei; Miwa, Kyoko; Yuan, Lixing; von Wirén, Nicolaus; Fujiwara, Toru

    2005-01-01

    Boron (B) is essential for plants but toxic when present in excess. Arabidopsis thaliana BOR1 is a B exporter for xylem loading and is essential for efficient B translocation from roots to shoots under B limitation. B translocation to shoots was enhanced under B limitation in WT but not in bor1-1 mutant plants. The enhanced translocation was suppressed upon resupply of high levels of B within several hours. Unlike a number of transporters for essential mineral nutrients, BOR1 mRNA accumulatio...

  9. Localization of Iron in Arabidopsis Seed Requires the Vacuolar Membrane Transporter VIT1

    International Nuclear Information System (INIS)

    Iron deficiency is a major human nutritional problem wherever plant-based diets are common. Using synchrotron x-ray fluorescence microtomography to directly visualize iron in Arabidopsis seeds, we show that iron is localized primarily to the provascular strands of the embryo. This localization is completely abolished when the vacuolar iron uptake transporter VIT1 is disrupted. Vacuolar iron storage is also critical for seedling development because vit1-1 seedlings grow poorly when iron is limiting. We have uncovered a fundamental aspect of seed biology that will ultimately aid the development of nutrient-rich seed, benefiting both human health and agricultural productivity

  10. Vacuolar-Iron-Transporter1-Like proteins mediate iron homeostasis in Arabidopsis.

    Science.gov (United States)

    Gollhofer, Julia; Timofeev, Roman; Lan, Ping; Schmidt, Wolfgang; Buckhout, Thomas J

    2014-01-01

    Iron deficiency is a nutritional problem in plants and reduces crop productivity, quality and yield. With the goal of improving the iron (Fe) storage properties of plants, we have investigated the function of three Arabidopsis proteins with homology to Vacuolar Iron Transporter1 (AtVIT1). Heterologous expression of Vacuolar Iron Transporter-Like1 (AtVTL1; At1g21140), AtVTL2 (At1g76800) or AtVTL5 (At3g25190) in the yeast vacuolar Fe transport mutant, Δccc1, restored growth in the presence of 4 mM Fe. Isolated vacuoles from yeast expressing either of the VTL genes in the Δccc1 background had a three- to four-fold increase in Fe concentration compared to vacuoles isolated from the untransformed mutant. Transiently expressed GFP-tagged AtVTL1 was localized exclusively and AtVTL2 was localized primarily to the vacuolar membrane of onion epidermis cells. Seedling root growth of the Arabidopsis nramp3/nramp4 and vit1-1 mutants was decreased compared to the wild type when seedlings were grown under Fe deficiency. When expressed under the 35S promoter in the nramp3/nramp4 or vit1-1 backgrounds, AtVTL1, AtVTL2 or AtVTL5 restored root growth in both mutants. The seed Fe concentration in the nramp3/nramp4 mutant overexpressing AtVTL1, AtVTL2 or AtVTL5 was between 50 and 60% higher than in non-transformed double mutants or wild-type plants. We conclude that the VTL proteins catalyze Fe transport into vacuoles and thus contribute to the regulation of Fe homeostasis in planta. PMID:25360591

  11. The Five AhMTP1 Zinc Transporters Undergo Different Evolutionary Fates towards Adaptive Evolution to Zinc Tolerance in Arabidopsis halleri

    OpenAIRE

    Shahzad, Zaigham; Gosti, Françoise; Frérot, Hélène; Lacombe, Eric; Roosens, Nancy; Saumitou-Laprade, Pierre; Berthomieu, Pierre

    2010-01-01

    Gene duplication is a major mechanism facilitating adaptation to changing environments. From recent genomic analyses, the acquisition of zinc hypertolerance and hyperaccumulation characters discriminating Arabidopsis halleri from its zinc sensitive/non-accumulator closest relatives Arabidopsis lyrata and Arabidopsis thaliana was proposed to rely on duplication of genes controlling zinc transport or zinc tolerance. Metal Tolerance Protein 1 (MTP1) is one of these genes. It encodes a Zn2+/H+ an...

  12. A link between magnesium-chelatase H subunit and sucrose nonfermenting 1 (SNF1)-related protein kinase SnRK2.6/OST1 in Arabidopsis guard cell signalling in response to abscisic acid.

    Science.gov (United States)

    Liang, Shan; Lu, Kai; Wu, Zhen; Jiang, Shang-Chuan; Yu, Yong-Tao; Bi, Chao; Xin, Qi; Wang, Xiao-Fang; Zhang, Da-Peng

    2015-10-01

    Magnesium-chelatase H subunit [CHLH/putative abscisic acid (ABA) receptor ABAR] positively regulates guard cell signalling in response to ABA, but the molecular mechanism remains largely unknown. A member of the sucrose nonfermenting 1 (SNF1)-related protein kinase 2 family, SnRK2.6/open stomata 1 (OST1)/SRK2E, which plays a critical role in ABA signalling in Arabidopsis guard cells, interacts with ABAR/CHLH. Neither mutation nor over-expression of the ABAR gene affects significantly ABA-insensitive phenotypes of stomatal movement in the OST1 knockout mutant allele srk2e. However, OST1 over-expression suppresses ABA-insensitive phenotypes of the ABAR mutant allele cch in stomatal movement. These genetic data support that OST1 functions downstream of ABAR in ABA signalling in guard cells. Consistent with this, ABAR protein is phosphorylated, but independently of the OST1 protein kinase. Two ABAR mutant alleles, cch and rtl1, show ABA insensitivity in ABA-induced reactive oxygen species and nitric oxide production, as well as in ABA-activated phosphorylation of a K(+) inward channel KAT1 in guard cells, which is consistent with that observed in the pyr1 pyl1 pyl2 pyl4 quadruple mutant of the well-characterized ABA receptor PYR/PYL/RCAR family acting upstream of OST1. These findings suggest that ABAR shares, at least in part, downstream signalling components with PYR/PYL/RCAR receptors for ABA in guard cells; though cch and rtl1 show strong ABA-insensitive phenotypes in both ABA-induced stomatal closure and inhibition of stomatal opening, while the pyr1 pyl1 pyl2 pyl4 quadruple mutant shows strong ABA insensitivity only in ABA-induced stomatal closure. These data establish a link between ABAR/CHLH and SnRK2.6/OST1 in guard cell signalling in response to ABA. PMID:26175350

  13. Sucrose nonfermenting AMPK-related kinase (SNARK) mediates contraction-stimulated glucose transport in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Koh, Ho-Jin; Toyoda, Taro; Fujii, Nobuharu;

    2010-01-01

    The signaling mechanisms that mediate the important effects of contraction to increase glucose transport in skeletal muscle are not well understood, but are known to occur through an insulin-independent mechanism. Muscle-specific knockout of LKB1, an upstream kinase for AMPK and AMPK....... Whole-body SNARK heterozygotic knockout mice also had impaired contraction-stimulated glucose transport in skeletal muscle, and knockdown of SNARK in C2C12 muscle cells impaired sorbitol-stimulated glucose transport. SNARK is activated by muscle contraction and is a unique mediator of contraction......-stimulated glucose transport in skeletal muscle....

  14. 拟南芥MicroRNA828负调控蔗糖诱导的花青素合成%MicroRNA828 Negatively Regulates Sucrose-Induced Anthocyanin Biosynthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    谢烨; 孙毅; 李淡宁; 黄继荣

    2013-01-01

    花青素生物合成途径及转录调控因子虽然已基本被阐明,但其调控机理仍在日益更新.本研究利用蔗糖诱导花青素合成的表型,建立了一种筛选拟南芥花青素代谢突变体的方法.我们从T-DNA插入突变体库中筛选出一株花青素合成过量突变体,基因克隆结果表明是由MicroRNA828 (miR828)的功能缺失所致.进一步研究发现miR828过表达植株中蔗糖诱导的花青素积累较野生型减少,这与敲除miR828的靶基因TAS4导致花青素积累比野生型高的结果一致,表明miR828负调控花青素合成.miR828在各组织中表达量很低,但其表达受到蔗糖诱导.在讨论中,我们提出了miR828调控蔗糖诱导花青素合成的模型.%Anthocyanins displaying from red, blue to purple give plants a colorful world. They play an important role in pollination, seed dispersal, and stress resistance. Although the anthocyanin biosynthetic pathway and the transcription factors have been well-documented, regulatory mechanisms underlying anthocyanin biosynthesis are not fully understood. In this study, we established a system to screen mutants with high accumulation of anthocyanin in Arabidopsis thaliana, and provided new evidence that small RNA is involved in anthocyanin biosynthesis. Using the phenomenon of sugar-induced anthocyanin biosynthesis, we obtained a mutant accumulated a higher level of anthocyanin compared with the wild type (WT). TAIL-PCR analysis revealed that the phenotype was resulted from the loss-of-function microRNA828 (miR828). Consistently, anthocyanin content was reduced in miR828 overexpressors under sucrose treatment. In addition, knockout of TAS4, the target of miR828, also led to higher accumulation of anthocyanin in sugar-treated seedlings compared with WT. These results indicate that miR828 negatively regulates anthocyanin biosynthesis. Further analysis demonstrated that the expression level of miR828 was quite low in various tissues, but was

  15. The Vacuolar Manganese Transporter MTP8 Determines Tolerance to Iron Deficiency-Induced Chlorosis in Arabidopsis.

    Science.gov (United States)

    Eroglu, Seckin; Meier, Bastian; von Wirén, Nicolaus; Peiter, Edgar

    2016-02-01

    Iron (Fe) deficiency is a widespread nutritional disorder on calcareous soils. To identify genes involved in the Fe deficiency response, Arabidopsis (Arabidopsis thaliana) transfer DNA insertion lines were screened on a high-pH medium with low Fe availability. This approach identified METAL TOLERANCE PROTEIN8 (MTP8), a member of the Cation Diffusion Facilitator family, as a critical determinant for the tolerance to Fe deficiency-induced chlorosis, also on soil substrate. Subcellular localization to the tonoplast, complementation of a manganese (Mn)-sensitive Saccharomyces cerevisiae yeast strain, and Mn sensitivity of mtp8 knockout mutants characterized the protein as a vacuolar Mn transporter suitable to prevent plant cells from Mn toxicity. MTP8 expression was strongly induced on low-Fe as well as high-Mn medium, which were both strictly dependent on the transcription factor FIT, indicating that high-Mn stress induces Fe deficiency. mtp8 mutants were only hypersensitive to Fe deficiency when Mn was present in the medium, which further suggested an Mn-specific role of MTP8 during Fe limitation. Under those conditions, mtp8 mutants not only translocated more Mn to the shoot than did wild-type plants but suffered in particular from critically low Fe concentrations and, hence, Fe chlorosis, although the transcriptional Fe deficiency response was up-regulated more strongly in mtp8. The diminished uptake of Fe from Mn-containing low-Fe medium by mtp8 mutants was caused by an impaired ability to boost the ferric chelate reductase activity, which is an essential process in Fe acquisition. These findings provide a mechanistic explanation for the long-known interference of Mn in Fe nutrition and define the molecular processes by which plants alleviate this antagonism. PMID:26668333

  16. Overexpression of OsWRKY72 gene interferes in the abscisic acid signal and auxin transport pathway of Arabidopsis

    Indian Academy of Sciences (India)

    Song Yu; Chen Ligang; Zhang Liping; Yu Diqiu

    2010-09-01

    Through activating specific transcriptional programmes, plants can launch resistance mechanisms to stressful environments and acquire a new equilibrium between development and defence. To screen the rice WRKY transcription factor which functions in abiotic stress tolerance and modulates the abscisic acid (ABA) response, we generated a whole array of 35S-OsWRKY transgenic Arabidopsis. In this study, we report that 35S-OsWRKY72 transgenic Arabidopsis, whose seed germination was retarded under normal conditions, emerged more sensitive to mannitol, NaCl, ABA stresses and sugar starvation than vector plants. Meanwhile, 35S-OsWRKY72 transgenic Arabidopsis displayed early flowering, reduced apical dominance, lost high temperature-induced hypocotyl elongation response, and enhanced gravitropism response, which were similar to the auxin-related gene mutants aux1, axr1 and bud1. Further, semi-quantitative RT-PCR showed that the expression patterns of three auxin-related genes AUX1, AXR1 and BUD1 were significantly altered in rosette leaves and inflorescences of 35S-OsWRKY72 plants compared with control Arabidopsis, and two ABA-related genes ABA2 and ABI4 were induced in 35S-OsWRKY72 seedlings. In addition, northern blot analysis indicated that, in rice, OsWRKY72 was inducible by polyethylene glycol (PEG), NaCl, naphthalene acetic acid (NAA), ABA and 42°C, similar to its orthologue AtWRKY75 in Arabidopsis, implying that these two WRKY genes might be required for multiple physiological processes in their plants. Together, these results suggest that OsWRKY72 interferes in the signal cross-talk between the ABA signal and auxin transport pathway in transgenic Arabidopsis.

  17. Structure-Function Relationship of a Plant NCS1 Member – Homology Modeling and Mutagenesis Identified Residues Critical for Substrate Specificity of PLUTO, a Nucleobase Transporter from Arabidopsis

    OpenAIRE

    Sandra Witz; Pankaj Panwar; Markus Schober; Johannes Deppe; Farhan Ahmad Pasha; Joanne Lemieux, M; Torsten Möhlmann

    2014-01-01

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecula...

  18. Potassium Transporter KUP7 Is Involved in K(+) Acquisition and Translocation in Arabidopsis Root under K(+)-Limited Conditions.

    Science.gov (United States)

    Han, Min; Wu, Wei; Wu, Wei-Hua; Wang, Yi

    2016-03-01

    Potassium (K(+)) is one of the essential macronutrients for plant growth and development. K(+) uptake from environment and K(+) translocation in plants are conducted by K(+) channels and transporters. In this study, we demonstrated that KT/HAK/KUP transporter KUP7 plays crucial roles in K(+) uptake and translocation in Arabidopsis root. The kup7 mutant exhibited a sensitive phenotype on low-K(+) medium, whose leaves showed chlorosis symptoms compared with wild-type plants. Loss of function of KUP7 led to a reduction of K(+) uptake rate and K(+) content in xylem sap under K(+)-deficient conditions. Thus, the K(+) content in kup7 shoot was significantly reduced under low-K(+) conditions. Localization analysis revealed that KUP7 was predominantly targeted to the plasma membrane. The complementation assay in yeast suggested that KUP7 could mediate K(+) transport. In addition, phosphorylation on S80, S719, and S721 was important for KUP7 activity. KUP7 was ubiquitously expressed in many organs/tissues, and showed a higher expression level in Arabidopsis root. Together, our data demonstrated that KUP7 is crucial for K(+) uptake in Arabidopsis root and might be also involved in K(+) transport into xylem sap, affecting K(+) translocation from root toward shoot, especially under K(+)-limited conditions. PMID:26851373

  19. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Bjørnar Sporsheim

    2015-12-01

    Full Text Available Volatile allyl isothiocyanate (AITC derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER, vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

  20. Mutations in the Arabidopsis Peroxisomal ABC Transporter COMATOSE Allow Differentiation between Multiple Functions In Planta: Insights from an Allelic Series

    OpenAIRE

    Dietrich, Daniela; Schmuths, Heike; Lousa, Carine De Marcos; Baldwin, Jocelyn M.; Baldwin, Stephen A.; Baker, Alison; Theodoulou, Frederica L; Holdsworth, Michael J

    2009-01-01

    COMATOSE (CTS), the Arabidopsis homologue of human Adrenoleukodystrophy protein (ALDP), is required for import of substrates for peroxisomal β-oxidation. A new allelic series and a homology model based on the bacterial ABC transporter, Sav1866, provide novel insights into structure-function relations of ABC subfamily D proteins. In contrast to ALDP, where the majority of mutations result in protein absence from the peroxisomal membrane, all CTS mutants produced stable protein. Mutation of con...

  1. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana

    OpenAIRE

    Stefanato, Francesca L.; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G.; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-01-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mut...

  2. PIN6 auxin transporter at endoplasmic reticulum and plasma membrane mediates auxin homeostasis and organogenesis in Arabidopsis.

    Science.gov (United States)

    Simon, Sibu; Skůpa, Petr; Viaene, Tom; Zwiewka, Marta; Tejos, Ricardo; Klíma, Petr; Čarná, Mária; Rolčík, Jakub; De Rycke, Riet; Moreno, Ignacio; Dobrev, Petre I; Orellana, Ariel; Zažímalová, Eva; Friml, Jiří

    2016-07-01

    Plant development mediated by the phytohormone auxin depends on tightly controlled cellular auxin levels at its target tissue that are largely established by intercellular and intracellular auxin transport mediated by PIN auxin transporters. Among the eight members of the Arabidopsis PIN family, PIN6 is the least characterized candidate. In this study we generated functional, fluorescent protein-tagged PIN6 proteins and performed comprehensive analysis of their subcellular localization and also performed a detailed functional characterization of PIN6 and its developmental roles. The localization study of PIN6 revealed a dual localization at the plasma membrane (PM) and endoplasmic reticulum (ER). Transport and metabolic profiling assays in cultured cells and Arabidopsis strongly suggest that PIN6 mediates both auxin transport across the PM and intracellular auxin homeostasis, including the regulation of free auxin and auxin conjugates levels. As evidenced by the loss- and gain-of-function analysis, the complex function of PIN6 in auxin transport and homeostasis is required for auxin distribution during lateral and adventitious root organogenesis and for progression of these developmental processes. These results illustrate a unique position of PIN6 within the family of PIN auxin transporters and further add complexity to the developmentally crucial process of auxin transport. PMID:27240710

  3. Identification of a Stelar-Localized Transport Protein That Facilitates Root-to-Shoot Transfer of Chloride in Arabidopsis

    KAUST Repository

    Li, Bo

    2015-12-11

    Under saline conditions, higher plants restrict the accumulation of chloride ions (Cl–) in the shoot by regulating their transfer from the root symplast into the xylem-associated apoplast. To identify molecular mechanisms underpinning this phenomenon, we undertook a transcriptional screen of salt stressed Arabidopsis (Arabidopsis thaliana) roots. Microarrays, quantitative RT-PCR, and promoter-GUS fusions identified a candidate gene involved in Cl– xylem loading from the Nitrate transporter 1/Peptide Transporter family (NPF2.4). This gene was highly expressed in the root stele compared to the cortex, and its expression decreased after exposure to NaCl or abscisic acid. NPF2.4 fused to fluorescent proteins, expressed either transiently or stably, was targeted to the plasma membrane. Electrophysiological analysis of NPF2.4 in Xenopus laevis oocytes suggested that NPF2.4 catalyzed passive Cl– efflux out of cells and was much less permeable to NO3−. Shoot Cl– accumulation was decreased following NPF2.4 artificial microRNA knockdown, whereas it was increased by overexpression of NPF2.4. Taken together, these results suggest that NPF2.4 is involved in long-distance transport of Cl– in plants, playing a role in the loading and the regulation of Cl– loading into the xylem of Arabidopsis roots during salinity stress.

  4. Screening for plant transporter function by expressing a normalized Arabidopsis full-length cDNA library in Xenopus oocytes

    Directory of Open Access Journals (Sweden)

    Halkier Barbara A

    2006-10-01

    Full Text Available Abstract Background We have developed a functional genomics approach based on expression cloning in Xenopus oocytes to identify plant transporter function. We utilized the full-length cDNA databases to generate a normalized library consisting of 239 full-length Arabidopsis thaliana transporter cDNAs. The genes were arranged into a 96-well format and optimized for expression in Xenopus oocytes by cloning each coding sequence into a Xenopus expression vector. Results Injection of 96 in vitro transcribed cRNAs from the library in pools of columns and rows into oocytes and subsequent screening for glucose uptake activity identified three glucose transporters. One of these, AtSTP13, had not previously been experimentally characterized. Conclusion Expression of the library in Xenopus oocytes, combined with uptake assays, has great potential in assignment of plant transporter function and for identifying membrane transporters for the many plant metabolites where a transporter has not yet been identified.

  5. Arabidopsis thaliana High-Affinity Phosphate Transporters Exhibit Multiple Levels of Posttranslational Regulation[C][W

    Science.gov (United States)

    Bayle, Vincent; Arrighi, Jean-François; Creff, Audrey; Nespoulous, Claude; Vialaret, Jérôme; Rossignol, Michel; Gonzalez, Esperanza; Paz-Ares, Javier; Nussaume, Laurent

    2011-01-01

    In Arabidopsis thaliana, the PHOSPHATE TRANSPORTER1 (PHT1) family encodes the high-affinity phosphate transporters. They are transcriptionally induced by phosphate starvation and require PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR (PHF1) to exit the endoplasmic reticulum (ER), indicating intracellular traffic as an additional level of regulation of PHT1 activity. Our study revealed that PHF1 acts on PHT1, upstream of vesicle coat protein COPII formation, and that additional regulatory events occur during PHT1 trafficking and determine its ER exit and plasma membrane stability. Phosphoproteomic and mutagenesis analyses revealed modulation of PHT1;1 ER export by Ser-514 phosphorylation status. Confocal microscopy analysis of root tip cells showed that PHT1;1 is localized to the plasma membrane and is present in intracellular endocytic compartments. More precisely, PHT1;1 was localized to sorting endosomes associated with prevacuolar compartments. Kinetic analysis of PHT1;1 stability and targeting suggested a modulation of PHT1 internalization from the plasma membrane to the endosomes, followed by either subsequent recycling (in low Pi) or vacuolar degradation (in high Pi). For the latter condition, we identified a rapid mechanism that reduces the pool of PHT1 proteins present at the plasma membrane. This mechanism is regulated by the Pi concentration in the medium and appears to be independent of degradation mechanisms potentially regulated by the PHO2 ubiquitin conjugase. We propose a model for differential trafficking of PHT1 to the plasma membrane or vacuole as a function of phosphate concentration. PMID:21521698

  6. Modelling the dynamics of polar auxin transport in inflorescence stems of Arabidopsis thaliana.

    Science.gov (United States)

    Boot, Kees J M; Hille, Sander C; Libbenga, Kees R; Peletier, Lambertus A; van Spronsen, Paulina C; van Duijn, Bert; Offringa, Remko

    2016-02-01

    The polar transport of the plant hormone auxin has been the subject of many studies, several involving mathematical modelling. Unfortunately, most of these models have not been experimentally verified. Here we present experimental measurements of long-distance polar auxin transport (PAT) in segments of inflorescence stems of Arabidopsis thaliana together with a descriptive mathematical model that was developed from these data. It is based on a general advection-diffusion equation for auxin density, as suggested by the chemiosmotic theory, but is extended to incorporate both immobilization of auxin and exchange with the surrounding tissue of cells involved in PAT, in order to account for crucial observations. We found that development of the present model assisted effectively in the analysis of experimental observations. As an example, we discuss the analysis of a quadruple mutant for all four AUX1/LAX1-LAX3 influx carriers genes. We found a drastic change in the parameters governing the exchange of PAT channels with the surrounding tissue, whereas the velocity was still of the order of magnitude of the wild type. In addition, the steady-state flux of auxin through the PAT system of the mutant did not exhibit a saturable component, as we found for the wild type, suggesting that the import carriers are responsible for the saturable component in the wild type. In the accompanying Supplementary data available at JXB online, we describe in more detail the data-driven development of the model, review and derive predictions from a mathematical model of the chemiosmotic theory, and explore relationships between parameters in our model and processes and parameters at the cellular level. PMID:26531101

  7. Modelling the dynamics of polar auxin transport in inflorescence stems of Arabidopsis thaliana

    Science.gov (United States)

    Boot, Kees J.M.; Hille, Sander C.; Libbenga, Kees R.; Peletier, Lambertus A.; van Spronsen, Paulina C.; van Duijn, Bert; Offringa, Remko

    2016-01-01

    The polar transport of the plant hormone auxin has been the subject of many studies, several involving mathematical modelling. Unfortunately, most of these models have not been experimentally verified. Here we present experimental measurements of long-distance polar auxin transport (PAT) in segments of inflorescence stems of Arabidopsis thaliana together with a descriptive mathematical model that was developed from these data. It is based on a general advection–diffusion equation for auxin density, as suggested by the chemiosmotic theory, but is extended to incorporate both immobilization of auxin and exchange with the surrounding tissue of cells involved in PAT, in order to account for crucial observations. We found that development of the present model assisted effectively in the analysis of experimental observations. As an example, we discuss the analysis of a quadruple mutant for all four AUX1/LAX1–LAX3 influx carriers genes. We found a drastic change in the parameters governing the exchange of PAT channels with the surrounding tissue, whereas the velocity was still of the order of magnitude of the wild type. In addition, the steady-state flux of auxin through the PAT system of the mutant did not exhibit a saturable component, as we found for the wild type, suggesting that the import carriers are responsible for the saturable component in the wild type. In the accompanying Supplementary data available at JXB online, we describe in more detail the data-driven development of the model, review and derive predictions from a mathematical model of the chemiosmotic theory, and explore relationships between parameters in our model and processes and parameters at the cellular level. PMID:26531101

  8. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    International Nuclear Information System (INIS)

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd2+ uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance

  9. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wentao; Du, Bojing; Liu, Di; Qi, Xiaoting, E-mail: qixiaoting@cnu.edu.cn

    2014-12-12

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd{sup 2+} uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.

  10. The arabidopsis thaliana AGRAVITROPIC 1 gene encodes a component of the polar-auxin-transport efflux carrier

    Science.gov (United States)

    Chen, R.; Hilson, P.; Sedbrook, J.; Rosen, E.; Caspar, T.; Masson, P. H.

    1998-01-01

    Auxins are plant hormones that mediate many aspects of plant growth and development. In higher plants, auxins are polarly transported from sites of synthesis in the shoot apex to their sites of action in the basal regions of shoots and in roots. Polar auxin transport is an important aspect of auxin functions and is mediated by cellular influx and efflux carriers. Little is known about the molecular identity of its regulatory component, the efflux carrier [Estelle, M. (1996) Current Biol. 6, 1589-1591]. Here we show that mutations in the Arabidopsis thaliana AGRAVITROPIC 1 (AGR1) gene involved in root gravitropism confer increased root-growth sensitivity to auxin and decreased sensitivity to ethylene and an auxin transport inhibitor, and cause retention of exogenously added auxin in root tip cells. We used positional cloning to show that AGR1 encodes a putative transmembrane protein whose amino acid sequence shares homologies with bacterial transporters. When expressed in Saccharomyces cerevisiae, AGR1 promotes an increased efflux of radiolabeled IAA from the cells and confers increased resistance to fluoro-IAA, a toxic IAA-derived compound. AGR1 transcripts were localized to the root distal elongation zone, a region undergoing a curvature response upon gravistimulation. We have identified several AGR1-related genes in Arabidopsis, suggesting a global role of this gene family in the control of auxin-regulated growth and developmental processes.

  11. Mutations in exocyst complex subunit SEC6 gene impaired polar auxin transport and PIN protein recycling in Arabidopsis primary root.

    Science.gov (United States)

    Tan, Xiaoyun; Feng, Yihong; Liu, Yulong; Bao, Yiqun

    2016-09-01

    Polar auxin transport, which is critical for land plant pattern formation and directional growth, is largely depended on asymmetric distribution of PIN proteins at the plasma membrane (PM). Endocytosis and recycling processes play important roles in regulating PIN protein distribution and abundance at the PM. Two subunits (SEC8, EXO70A1) of exocyst, an octameric vesicle-tethering complex, have been reported to be involved in PIN protein recycling in Arabidopsis. However, the function of exocyst complex in PIN protein recycling and polar auxin transport remains incompletely understood. In this study, we utilized two SEC6 down-regulation mutants (PRsec6-1 and PRsec6-2) to investigate the role of exocyst subunit SEC6 in the primary root development, polar auxin transport and PIN proteins recycling. We found that in PRsec6 mutants: 1. Primary root growth was retarded, and lateral root initiation were compromised. 2. Primary roots were sensitive to exogenous auxin 1-napthalene acetic acid (NAA) but not 2,4-dichlorophenoxy (2.4-D). 3. Recycling of PIN1 and PIN2 proteins from the Brefeldin A (BFA) compartment to the PM was delayed. 4. Vesicles accumulated in the primary root tip cells, especially accumulated in the cytosol closed to the PM. These results further demonstrated that the exocyst complex plays an important role in PIN protein recycling and polar auxin transport in Arabidopsis primary root. PMID:27457987

  12. Expression of the Znt1 zinc transporter from the metal hyperaccumulator noccaea caerulescens confers enhanced zinc and cadmium tolerance and accumulation to arabidopsis thaliana

    NARCIS (Netherlands)

    Lin, Ya Fen; Hassan, Zeshan; Talukdar, S.; Schat, Henk; Aarts, Mark G.M.

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis.

  13. Large-Scale Public Transcriptomic Data Mining Reveals a Tight Connection between the Transport of Nitrogen and Other Transport Processes in Arabidopsis.

    Science.gov (United States)

    He, Fei; Karve, Abhijit A; Maslov, Sergei; Babst, Benjamin A

    2016-01-01

    Movement of nitrogen to the plant tissues where it is needed for growth is an important contribution to nitrogen use efficiency. However, we have very limited knowledge about the mechanisms of nitrogen transport. Loading of nitrogen into the xylem and/or phloem by transporter proteins is likely important, but there are several families of genes that encode transporters of nitrogenous molecules (collectively referred to as N transporters here), each comprised of many gene members. In this study, we leveraged publicly available microarray data of Arabidopsis to investigate the gene networks of N transporters to elucidate their possible biological roles. First, we showed that tissue-specificity of nitrogen (N) transporters was well reflected among the public microarray data. Then, we built coexpression networks of N transporters, which showed relationships between N transporters and particular aspects of plant metabolism, such as phenylpropanoid biosynthesis and carbohydrate metabolism. Furthermore, genes associated with several biological pathways were found to be tightly coexpressed with N transporters in different tissues. Our coexpression networks provide information at the systems-level that will serve as a resource for future investigation of nitrogen transport systems in plants, including candidate gene clusters that may work together in related biological roles. PMID:27563305

  14. Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTERS 1 and 2: fructose and xylitol/H+ symporters in pollen and young xylem cells

    OpenAIRE

    Klepek, Yvonne-Simone; Volke, Melanie; Konrad, Kai R.; Wippel, Kathrin; Hoth, Stefan; Hedrich, Rainer; Sauer, Norbert

    2009-01-01

    The genome of Arabidopsis thaliana contains six genes, AtPMT1 to AtPMT6 (Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTER 1–6), which form a distinct subfamily within the large family of more than 50 monosaccharide transporter-like (MST-like) genes. So far, only AtPMT5 [formerly named AtPLT5 (At3g18830)] has been characterized and was shown to be a plasma membrane-localized H+-symporter with broad substrate specificity. The characterization of AtPMT1 (At2g16120) and AtPMT2 (At2g16130), ...

  15. Transferases and transporters mediate the detoxification and capacity to tolerate trinitrotoluene in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Landa, Přemysl; Štorchová, Helena; Hodek, J.; Vaňková, Radomíra; Podlipná, Radka; Maršík, Petr; Ovesná, J.; Vaněk, Tomáš

    2010-01-01

    Roč. 10, č. 4 (2010), s. 547-559. ISSN 1438-793X R&D Projects: GA MŠk 2B06187; GA MŠk 2B08058 Institutional research plan: CEZ:AV0Z50380511 Keywords : Microarrays * Arabidopsis thaliana * TNT Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.397, year: 2010

  16. Functional Characterization of AtSP1, A Sucrose-Responsive Receptor-Like Kinase

    Institute of Scientific and Technical Information of China (English)

    Xuna Wu; Kerstin Zander; Eugenia Maximova; Gerhard Obermeyer; Waltraud Schulze

    2012-01-01

    Sucrose is the main product of photosynthesis and an important metabolite.It functions as signaling molecule,also potentially being involved in the regulation of growth and development in plants.AtSP1 is one of putative RLKs identified in sucrose resupply after starvation experiment and hypothesized to be involved in sucrose-related regulatory processes (Niittyl(a) et al.,2007).The aim of this work was to characterize the effect of AtSP1 and its phosphorylation site Ser744 on sucrose induced phosphorylation cascade.Therefore,proteins which changed their phosphorylation status upon sucrose supply were compared in WT,the sp1 mutant,complementation lines (35S::AtSP1-GFP/sp1),and two mutagenesis lines (35S::AtSP1S744A-GFP/sp1 and 35S::AtSP1S744D-GFP/sp1).Proteins with altered phosphorylation response in the mutant lines are candidates for direct or indirect substrates of AtSP1.To test this,Arabidopsis seedlings were cultured for 24 h without sucrose in JPL medium,and either sucrose or mannitol was resupplied for 3 min.The treatment time of 3 min was chosen as the maximum phosphorylation change of AtSP1 occurred after 3 min (Niittyl(a) et al.,2007).Seedlings were then harvested.The soluble proteins and microsome fraction were isolated and identified via LC-MS/MS.The phosphorylated amino acids were identified by MAXQUANT and quantified based on normalized ion intensities.The quantified phosphoproteins in five genotypes were compared to find candidate proteins which could be regulated by AtSP1 in response to sucrose resupply after starvation.The analysis of the short term effects regulated by AtSP1 provided new insights about sucrose-induced regulatory processes.In total,93 phosphoproteins were identified,42 of which showed a significant lower phosphorylation in the sp1 mutant.These results indicated that when expression levels of AtSP1 were severely reduced,multiple other proteins were impaired in their phosphorylation upon sucrose reply,linking them potentially with At

  17. Ectopic expression of Arabidopsis ABC transporter MRP7 modifies cadmium root-to-shoot transport and accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Wojas, Sylwia [Faculty of Biology, University of Warsaw, Miecznikowa str. 1, 02-096 Warszawa (Poland); Hennig, Jacek [Institute of Biochemistry and Biophysics PAS, Pawinskiego str. 5A, 02-106 Warszawa (Poland); Plaza, Sonia; Geisler, Markus [Institute of Plant Biology, University of Zuerich, CH-8008 Zuerich (Switzerland); Siemianowski, Oskar; Sklodowska, Aleksandra [Faculty of Biology, University of Warsaw, Miecznikowa str. 1, 02-096 Warszawa (Poland); Ruszczynska, Anna; Bulska, Ewa [Faculty of Chemistry, University of Warsaw, Pasteura str.1, 02-093 Warszawa (Poland); Antosiewicz, Danuta M., E-mail: dma@biol.uw.edu.p [Faculty of Biology, University of Warsaw, Miecznikowa str. 1, 02-096 Warszawa (Poland)

    2009-10-15

    Arabidopsis MRPs/ABCCs have been shown to remove various organic and inorganic substrates from the cytosol to other subcellular compartments. Here we first demonstrate that heterologous expression of AtMRP7 in tobacco (Nicotiana tabacum var. Xanthi) modifies cadmium accumulation, distribution and tolerance. Arabidopsis MRP7 was localized both in the tonoplast and in the plasma membrane when expressed in tobacco. Its overexpression increased tobacco Cd-tolerance and resulted in enhanced cadmium concentration in leaf vacuoles, indicating more efficient detoxification by means of vacuolar storage. Heterologous AtMRP7 expression also led to more efficient retention of Cd in roots, suggesting a contribution to the control of cadmium root-to-shoot translocation. The results underscore the use of AtMRP7 in plant genetic engineering to modify the heavy-metal accumulation pattern for a broad range of applications. - AtMRP7 expression in tobacco enhances Cd-tolerance and increases Cd storage in vacuoles

  18. Evidence for the presence of a sucrose carrier in immature sugar beet tap roots

    International Nuclear Information System (INIS)

    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'-fluorosucrose (F-sucrose) which is a poor substrate for acid invertase but is a substrate for sucrose synthase. Ten millimolar each of [3H] sucrose and [14C]F-sucrose were applied in a 1:1 ratio to an abraded region of an attached leaf for 6 hours. [14C]F-sucrose was translocated and accumulated in the roots at a higher rate than [3H]sucrose. This was due to [3H]sucrose hydrolysis along the translocation path. Presence of [3H]hexose and [14C]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

  19. Deletion of a Histidine-rich Loop of AtMTP1, a Vacuolar Zn2+/H+ Antiporter of Arabidopsis thaliana, Stimulates the Transport Activity*

    OpenAIRE

    Kawachi, Miki; Kobae, Yoshihiro; Mimura, Tetsuro; Maeshima, Masayoshi

    2008-01-01

    Arabidopsis thaliana AtMTP1 belongs to the cation diffusion facilitator family and is localized on the vacuolar membrane. We investigated the enzymatic kinetics of AtMTP1 by a heterologous expression system in the yeast Saccharomyces cerevisiae, which lacked genes for vacuolar membrane zinc transporters ZRC1 and COT1. The yeast mutant expressing AtMTP1 heterologously was tolerant to 10 mm ZnCl2. Active transport of zinc into vacuoles of living yeast cells expressing At...

  20. The response of Arabidopsis root water transport to a challenging environment implicates reactive oxygen species- and phosphorylation-dependent internalization of aquaporins

    OpenAIRE

    Boursiac, Yann; Prak, Sodana; Boudet, Julie; Postaire, Olivier; Luu, Doan-Trung; Tournaire-Roux, Colette; Santoni, Véronique; Maurel, Christophe

    2008-01-01

    Aquaporins, which facilitate the diffusion of water across biological membranes, are key molecules for the regulation of water transport at the cell and organ levels. We recently reported that hydrogen peroxide (H2O2) acts as an intermediate in the regulation of Arabidopsis root water transport and aquaporins in response to NaCl and salicylic acid (SA).1 Its action involves signaling pathways and an internalization of aquaporins from the cell surface. The present addendum connects these findi...

  1. Uncovering Arabidopsis membrane protein interactome enriched in transporters using mating-based split ubiquitin assays and classification models

    Directory of Open Access Journals (Sweden)

    Jin eChen

    2012-06-01

    Full Text Available High-throughput data are a double-edged sword; for the benefit of large amount of data, there is an associated cost of noise. To increase reliability and scalability of high-throughput protein interaction data generation, we tested the efficacy of classification to enrich potential protein-protein interactions (pPPIs. We applied this method to identify interactions among Arabidopsis membrane proteins enriched in transporters. We validated our method with multiple retests. Classification improved the quality of the ensuing interaction network and was effective in reducing the search space and increasing true positive rate. The final network of 541 interactions among 239 proteins (of which 179 are transporters is the first protein interaction network enriched in membrane transporters reported for any organism. This network has similar topological attributes to other published protein interaction networks. It also extends and fills gaps in currently available biological networks in plants and allows building a number of hypotheses about processes and mechanisms involving signal-transduction and transport systems.

  2. Studies on the role of heavy-metal transporting P-type ATPase family genes on zinc (Zn) transport and accumulation in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Bagavathiannan, M.V. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Plant Science; Broadley, M.R.; Donnelly, S.J.; Smith, R.J.; Mills, V. [Nottingham Univ., Loughborough, Leicestershire (United Kingdom). School of Biosciences, Plant Sciences Division

    2006-07-01

    Although zinc (Zn) is an essential plant mineral nutrient for normal crop growth, excess amounts can cause environmental contamination problems. Higher amounts of Zn are added into soils every year through effluents from tanning industries and other sources such as sewage treatment plants, metal inputs from rivers and the atmosphere. Studies have shown that specific metal tolerances exist at the cellular level in plants, indicating that specific adaptations to metal ions occur in cells as well as in the whole plant. This paper described the mechanisms that plants develop in order to tolerate heavy metals and showed that transporter genes play a key role in uptake and sequestration of heavy metals in plant systems. Since metal ion transporting genes are also involved in transport and homeostasis of heavy metals in plants, this study examined the role of the metal ion transporting gene family members in Zn transport and tolerance in plant systems. Among the metal ion transporting gene families, P-type ATPase gene family members are considered to be efficient in metal transport in the model plant Arabidopsis thaliana. They form a diverse superfamily of transporters which carry a range of essential and potentially toxic metals across cellular membranes. Genetic-screening experiments were performed in which 3 SALK lines with known disruption in the target gene were studied physiologically and at the molecular level to determine their role in heavy-metal transportation and accumulation. The study showed that one of the family lines may have altered Zn tolerance and uptake characteristics. Ongoing research continues to examine the characteristics of this line. 27 refs., 1 tab., 8 figs.

  3. Sucrose Metabolism in Plastids

    NARCIS (Netherlands)

    Gerrits, N.; Turk, S.C.H.J.; Dun, van K.P.M.; Hulleman, H.D.; Visser, R.G.F.; Weisbeek, P.J.; Smeekens, S.C.M.

    2001-01-01

    The question whether sucrose (Suc) is present inside plastids has been long debated. Low Suc levels were reported to be present inside isolated chloroplasts, but these were argued to be artifacts of the isolation procedures used. We have introduced Suc-metabolizing enzymes in plastids and our experi

  4. Aluminium-induced ion transport in Arabidopsis: the relationship between Al tolerance and root ion flux

    OpenAIRE

    Bose, Jayakumar; Babourina, Olga; Shabala, Sergey; RENGEL, ZED

    2010-01-01

    Aluminium (Al) rhizotoxicity coincides with low pH; however, it is unclear whether plant tolerance to these two factors is controlled by the same mechanism. To address this question, the Al-resistant alr104 mutant, two Al-sensitive mutants (als3 and als5), and wild-type Arabidopsis thaliana were compared in long-term exposure (solution culture) and in short-term exposure experiments (H+ and K+ fluxes, rhizosphere pH, and plasma membrane potential, E m). Based on biomass accumulation, als5 and...

  5. Arabidopsis SOI33/AtENT8 Gene Encodes a Putative Equilibrative Nucleoside Transporter That Is Involved in Cytokinin Transport In Planta

    Institute of Scientific and Technical Information of China (English)

    Jiaqiang SUN; Naoya HIROSE; Xingchun WANG; Pei WEN; Li XUE; Hitoshi SAKAKIBARA; Jianru ZUO

    2005-01-01

    The plant phytohormone cytokinin plays an important role in many facets of plant growth and development by regulating cell division and differentiation. Recent studies have shed significant light into the mechanisms of cytokinin metabolism and signaling. However, little is known about how the hormone is transported in planta, although it has been proposed that the hormone is presumably transported in nucleoside-conjugated forms. Here, we report the identification and characterization of cytokinin transport ers in Arabidopsis. We previously reported that a gain-of-function mutation in the PGA22/AtIPT8 gene caused overproduction of cytokinins in planta. In an effort to screen for suppressor of pga22/atipt8 (soi) mutants, we identified a mutant soi33-1. Molecular and genetic analyses indicated that SOI33 encodes a putative equilibrative nucleoside transporter (ENT), previously designated as AtENT8. Members of this small gene family are presumed to be involved in the transport of nucleosides in eukaryotic cells. Under conditions of nitrogen starvation, loss-of-function mutations in SOI33/AtENT8 or in a related gene AtENT3 cause a reduced sensitivity to the nucleoside-type cytokinins isopentenyladenine riboside (iPR) and trans zeatin riboside (tZR), but display a normal response to the free base-type cytokinins isopentenyladenine (iP) and trans-zeatin (tZ). Conversely, overexpression of SOI33/AtENT8 renders transgenic plants hyper sensitive to iPR but not to iP. An in planta measurement experiment indicated that uptake efficiency of 3H labeled iPR was reduced more than 40% in soi33 and atent3 mutants. However, a mutation inAtENT1 had no substantial effect on the cytokinin response and iPR uptake efficiency. Our results suggest that SOI33/ AtENT8 and AtENT3 are involved in the transport of nucleoside-type cytokinins in Arabidopsis.

  6. Complete Sucrose Metabolism Requires Fructose Phosphotransferase Activity in Corynebacterium glutamicum To Ensure Phosphorylation of Liberated Fructose

    OpenAIRE

    Dominguez, H.; Lindley, N. D.

    1996-01-01

    Sucrose uptake by Corynebacterium glutamicum involves a phosphoenolpyruvate-dependent sucrose phosphotransferase (PTS), but in the absence of fructokinase, further metabolism of the liberated fructose requires efflux of the fructose and reassimilation via the fructose PTS. Mutant strains lacking detectable fructose-transporting PTS activity accumulated fructose extracellularly but consumed sucrose at rates comparable to those of the wild-type strain.

  7. The Arabidopsis thylakoid transporter PHT4;1 influences phosphate availability for ATP synthesis and plant growth.

    Science.gov (United States)

    Karlsson, Patrik M; Herdean, Andrei; Adolfsson, Lisa; Beebo, Azeez; Nziengui, Hugues; Irigoyen, Sonia; Ünnep, Renáta; Zsiros, Ottó; Nagy, Gergely; Garab, Győző; Aronsson, Henrik; Versaw, Wayne K; Spetea, Cornelia

    2015-10-01

    The Arabidopsis phosphate transporter PHT4;1 was previously localized to the chloroplast thylakoid membrane. Here we investigated the physiological consequences of the absence of PHT4;1 for photosynthesis and plant growth. In standard growth conditions, two independent Arabidopsis knockout mutant lines displayed significantly reduced leaf size and biomass but normal phosphorus content. When mutants were grown in high-phosphate conditions, the leaf phosphorus levels increased and the growth phenotype was suppressed. Photosynthetic measurements indicated that in the absence of PHT4;1 stromal phosphate was reduced to levels that limited ATP synthase activity. This resulted in reduced CO2 fixation and accumulation of soluble sugars, limiting plant growth. The mutants also displayed faster induction of non-photochemical quenching than the wild type, in line with the increased contribution of ΔpH to the proton-motive force across thylakoids. Small-angle neutron scattering showed a smaller lamellar repeat distance, whereas circular dichroism spectroscopy indicated a perturbed long-range order of photosystem II (PSII) complexes in the mutant thylakoids. The absence of PHT4;1 did not alter the PSII repair cycle, as indicated by wild-type levels of phosphorylation of PSII proteins, inactivation and D1 protein degradation. Interestingly, the expression of genes for several thylakoid proteins was downregulated in the mutants, but the relative levels of the corresponding proteins were either not affected or could not be discerned. Based on these data, we propose that PHT4;1 plays an important role in chloroplast phosphate compartmentation and ATP synthesis, which affect plant growth. It also maintains the ionic environment of thylakoids, which affects the macro-organization of complexes and induction of photoprotective mechanisms. PMID:26255788

  8. Oligosaccharides Derived from Sucrose

    Science.gov (United States)

    Monsan, Pierre F.; Ouarné, Francois

    Sucrose is a non-reducing disaccharide, consisting of an α-D-glucopyranosyl residue and a β-D-fructofuranosyl residue linked covalently by their respective anomeric carbons (α-D-glucopyranosyl-1,2-β-D-fructofuranoside). It is not just a simple disaccharide, among others: in fact, the energy of its glycosidic bond is higher than that of a usual glycosidic bond. It is equal to 27.6 kJ/mol, which is similar to the energy of a nucleotide-sugar bond as in UDP-glucose or ADP-glucose. This means that sucrose is a protected and activated form of D-glucose (as well as of D-fructose), which plays a key role in the metabolism of plants, for a wide variety of synthesis reactions.

  9. Lipid transport mediated by Arabidopsis TGD proteins is unidirectional from the endoplasmic reticulum to the plastid

    Energy Technology Data Exchange (ETDEWEB)

    Xu, C.; Moellering, E. R., Muthan, B.; Fan, J.; Benning, C.

    2010-06-01

    The transfer of lipids between the endoplasmic reticulum (ER) and the plastid in Arabidopsis involves the TRIGALACTOSYLDIACYLGLYCEROL (TGD) proteins. Lipid exchange is thought to be bidirectional based on the presence of specific lipid molecular species in Arabidopsis mutants impaired in the desaturation of fatty acids of membrane lipids in the ER and plastid. However, it was unclear whether TGD proteins were required for lipid trafficking in both directions. This question was addressed through the analysis of double mutants of tgd1-1 or tgd4-3 in genetic mutant backgrounds leading to a defect in lipid fatty acid desaturation either in the ER (fad2) or the plastid (fad6). The fad6 tgd1-1 and fad6 tgd4-3 double mutants showed drastic reductions in the relative levels of polyunsaturated fatty acids and of galactolipids. The growth of these plants and the development of photosynthetic membrane systems were severely compromised, suggesting a disruption in the import of polyunsaturated fatty acid-containing lipid species from the ER. Furthermore, a forward-genetic screen in the tgd1-2 dgd1 mutant background led to the isolation of a new fad6-2 allele with a marked reduction in the amount of digalactosyldiacylglycerol. In contrast, the introduction of fad2, affecting fatty acid desaturation of lipids in the ER, into the two tgd mutant backgrounds did not further decrease the level of fatty acid desaturation in lipids of extraplastidic membranes. These results suggest that the role of TGD proteins is limited to plastid lipid import, but does not extend to lipid export from the plastid to extraplastidic membranes.

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

    Science.gov (United States)

    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

  11. Kaempferol 3-O-rhamnoside-7-O-rhamnoside is an endogenous flavonol inhibitor of polar auxin transport in Arabidopsis shoots

    OpenAIRE

    Yin, R.H.; Han, K.; Heller, W; Albert, A.; Dobrev, P. (Petre); Zažímalová, E. (Eva); Schaffner, A.R.

    2014-01-01

    Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. ...

  12. Structure-function relationship of a plant NCS1 member--homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from Arabidopsis.

    Science.gov (United States)

    Witz, Sandra; Panwar, Pankaj; Schober, Markus; Deppe, Johannes; Pasha, Farhan Ahmad; Lemieux, M Joanne; Möhlmann, Torsten

    2014-01-01

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. PMID:24621654

  13. Structure-function relationship of a plant NCS1 member - Homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from arabidopsis

    KAUST Repository

    Witz, Sandra

    2014-03-12

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. 2014 Witz et al.

  14. Structure-function relationship of a plant NCS1 member--homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Sandra Witz

    Full Text Available Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members.

  15. Structure-Function Relationship of a Plant NCS1 Member – Homology Modeling and Mutagenesis Identified Residues Critical for Substrate Specificity of PLUTO, a Nucleobase Transporter from Arabidopsis

    Science.gov (United States)

    Witz, Sandra; Panwar, Pankaj; Schober, Markus; Deppe, Johannes; Pasha, Farhan Ahmad; Lemieux, M. Joanne; Möhlmann, Torsten

    2014-01-01

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. PMID:24621654

  16. A chimeric protein of aluminum-activated malate transporter generated from wheat and Arabidopsis shows enhanced response to trivalent cations.

    Science.gov (United States)

    Sasaki, Takayuki; Tsuchiya, Yoshiyuki; Ariyoshi, Michiyo; Ryan, Peter R; Yamamoto, Yoko

    2016-07-01

    TaALMT1 from wheat (Triticum aestivum) and AtALMT1 from Arabidopsis thaliana encode aluminum (Al)-activated malate transporters, which confer acid-soil tolerance by releasing malate from roots. Chimeric proteins from TaALMT1 and AtALMT1 (Ta::At, At::Ta) were previously analyzed in Xenopus laevis oocytes. Those studies showed that Al could activate malate efflux from the Ta::At chimera but not from At::Ta. Here, functions of TaALMT1, AtALMT1 and the chimeric protein Ta::At were compared in cultured tobacco BY-2 cells. We focused on the sensitivity and specificity of their activation by trivalent cations. The activation of malate efflux by Al was at least two-fold greater in the chimera than the native proteins. All proteins were also activated by lanthanides (erbium, ytterbium, gadolinium, and lanthanum), but the chimera again released more malate than TaALMT1 or AtALMT1. In Xenopus oocytes, Al, ytterbium, and erbium activated inward currents from the native TaALMT1 and the chimeric protein, but gadolinium only activated currents from the chimera. Lanthanum inhibited currents from both proteins. These results demonstrated that function of the chimera protein was altered compared to the native proteins and was more responsive to a range of trivalent cations when expressed in plant cells. PMID:27039280

  17. Aluminium-induced ion transport in Arabidopsis: the relationship between Al tolerance and root ion flux.

    Science.gov (United States)

    Bose, Jayakumar; Babourina, Olga; Shabala, Sergey; Rengel, Zed

    2010-06-01

    Aluminium (Al) rhizotoxicity coincides with low pH; however, it is unclear whether plant tolerance to these two factors is controlled by the same mechanism. To address this question, the Al-resistant alr104 mutant, two Al-sensitive mutants (als3 and als5), and wild-type Arabidopsis thaliana were compared in long-term exposure (solution culture) and in short-term exposure experiments (H(+) and K(+) fluxes, rhizosphere pH, and plasma membrane potential, E(m)). Based on biomass accumulation, als5 and alr104 showed tolerance to low pH, whereas alr104 was tolerant to the combined low-pH/Al treatment. The sensitivity of the als5 and als3 mutants to the Al stress was similar. The Al-induced decrease in H(+) influx at the distal elongation zone (DEZ) and Al-induced H(+) efflux at the mature zone (MZ) were higher in the Al-sensitive mutants (als3 and als5) than in the wild type and the alr104 mutant. Under combined low-pH/Al treatment, alr104 and the wild type had depolarized plasma membranes for the entire 30 min measurement period, whereas in the Al-sensitive mutants (als3 and als5), initial depolarization to around -60 mV became hyperpolarization at -110 mV after 20 min. At the DEZ, the E(m) changes corresponded to the changes in K(+) flux: K(+) efflux was higher in alr104 and the wild type than in the als3 and als5 mutants. In conclusion, Al tolerance in the alr104 mutant correlated with E(m) depolarization, higher K(+) efflux, and higher H(+) influx, which led to a more alkaline rhizosphere under the combined low-pH/Al stress. Low-pH tolerance (als5) was linked to higher H(+) uptake under low-pH stress, which was abolished by Al exposure. PMID:20497972

  18. Synthesis of insecticidal sucrose esters

    Institute of Scientific and Technical Information of China (English)

    Song Zi-juan; Li Shu-jun; Chen Xi; Liu Li-mei; Song Zhan-qian

    2006-01-01

    Some synthetic sucrose esters (SE) are a relatively new class of insecticidal compounds produced by reacting sugars with fatty acids, which are safe for the environment. Especially, sucrose esters composed of C6-C12 fatty acids have desirable insecticidal properties against many soft-bodied arthropod pests. In our study, sucrose octanoate which has the highest activity against a range of arthropod species was synthesized by a trans-esterification method and proved its insecticidal property. Under the condition of a homogeneous liquid, sucrose octanoate was prepared by reacting ethyl octanoate with sucrose at reduced pressure; the yield was 79.11%. Sucrose octanoate synthesized was identified and its property analyzed by IR, TLC and spectrophotometric analysis. It was shown that the ratio of monoester to polyester in sucrose octanoate was 1.48:1. The insecticidal activity of the synthetic sucrose octanoate was evaluated at a concentration of 4 and 8 mg·mL-1. The mortality of first-instar larvae ofLymantria dispar from its contact toxicity was 72.5% after 36 hours, the revision insect reduced rate of Aphis glycines reached above 80% at 4 and 8 mg·mL-1 after being treated for 5 days. Since the SE products are nontoxic to humans and higher animals, fully biodegradable and hydrolyzed to readily metabolizable sucrose and fatty acid, they are not harmful to crops and appear to be good insecticide candidates.

  19. Proof of concept for a novel functional screening system for plant sucrose effluxers

    Directory of Open Access Journals (Sweden)

    Yuchan Zhou

    2014-07-01

    Full Text Available Membrane transporters play pivotal roles in facilitating sucrose transport in plants and their activities have been shown to impact plant growth rates and crop yield.  In contrast to the well-defined mechanism of sucrose influx across plasma membranes, less is known about sucrose efflux mechanisms and the membrane proteins supporting this function.  A major impediment blocking progress in this key area of plant science is the absence of a functional screening system for genes encoding sucrose effluxers.  Here we report a novel yeast system for screening sucrose effluxers based on sucrose release from yeast cells genetically modified to synthesize, but not to metabolize, sucrose.  Inhibiting sucrose metabolism was achieved using yeast strains, SEY 6210 and YSL4-6, carrying mutations in genes encoding invertase and maltase, respectively.  Genes encoding essential components of sucrose biosynthesis, sucrose phosphate synthase (SPS and sucrose phosphate phosphatase (SPP, were used to transform the two yeast hosts to make strains SuPy (from SEY6210 and Ysu (from YSL4-6.  Cultures of SuPy15 cells were found to be capable of synthesizing sucrose when supplied with various compounds as the sole carbon source, including non-fermentable sugars and non-sugar substrates.  A proof of concept of the screening system was demonstrated by transforming SuPy15 with sucrose transporter genes known to encode plasma membrane proteins that mediate sucrose efflux.  The robustness of the yeast SuPy15 system as a novel platform to screen putative plant sucrose effluxers is discussed.

  20. Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTERS 1 and 2: fructose and xylitol/H+ symporters in pollen and young xylem cells

    Science.gov (United States)

    Klepek, Yvonne-Simone; Konrad, Kai R.; Wippel, Kathrin; Hoth, Stefan; Hedrich, Rainer; Sauer, Norbert

    2010-01-01

    The genome of Arabidopsis thaliana contains six genes, AtPMT1 to AtPMT6 (Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTER 1–6), which form a distinct subfamily within the large family of more than 50 monosaccharide transporter-like (MST-like) genes. So far, only AtPMT5 [formerly named AtPLT5 (At3g18830)] has been characterized and was shown to be a plasma membrane-localized H+-symporter with broad substrate specificity. The characterization of AtPMT1 (At2g16120) and AtPMT2 (At2g16130), two other, almost identical, members of this transporter subfamily, are presented here. Expression of the AtPMT1 and AtPMT2 cDNAs in baker's yeast (Saccharomyces cerevisiae) revealed that these proteins catalyse the energy-dependent, high-capacity transport of fructose and xylitol, and the transport of several other compounds with lower rates. Expression of their cRNAs in Xenopus laevis oocytes showed that both proteins are voltage-dependent and catalyse the symport of their substrates with protons. Fusions of AtPMT1 or AtPMT2 with the green fluorescent protein (GFP) localized to Arabidopsis plasma membranes. Analyses of reporter genes performed with AtPMT1 or AtPMT2 promoter sequences showed expression in mature (AtPMT2) or germinating (AtPMT1) pollen grains, as well as in growing pollen tubes, hydathodes, and young xylem cells (both genes). The expression was confirmed with an anti-AtPMT1/AtPMT2 antiserum (αAtPMT1/2) raised against peptides conserved in AtPMT1 and AtPMT2. The physiological roles of the proteins are discussed and related to plant cell wall modifications. PMID:19969532

  1. Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTERS 1 and 2: fructose and xylitol/H+ symporters in pollen and young xylem cells.

    Science.gov (United States)

    Klepek, Yvonne-Simone; Volke, Melanie; Konrad, Kai R; Wippel, Kathrin; Hoth, Stefan; Hedrich, Rainer; Sauer, Norbert

    2010-01-01

    The genome of Arabidopsis thaliana contains six genes, AtPMT1 to AtPMT6 (Arabidopsis thaliana POLYOL/MONOSACCHARIDE TRANSPORTER 1-6), which form a distinct subfamily within the large family of more than 50 monosaccharide transporter-like (MST-like) genes. So far, only AtPMT5 [formerly named AtPLT5 (At3g18830)] has been characterized and was shown to be a plasma membrane-localized H(+)-symporter with broad substrate specificity. The characterization of AtPMT1 (At2g16120) and AtPMT2 (At2g16130), two other, almost identical, members of this transporter subfamily, are presented here. Expression of the AtPMT1 and AtPMT2 cDNAs in baker's yeast (Saccharomyces cerevisiae) revealed that these proteins catalyse the energy-dependent, high-capacity transport of fructose and xylitol, and the transport of several other compounds with lower rates. Expression of their cRNAs in Xenopus laevis oocytes showed that both proteins are voltage-dependent and catalyse the symport of their substrates with protons. Fusions of AtPMT1 or AtPMT2 with the green fluorescent protein (GFP) localized to Arabidopsis plasma membranes. Analyses of reporter genes performed with AtPMT1 or AtPMT2 promoter sequences showed expression in mature (AtPMT2) or germinating (AtPMT1) pollen grains, as well as in growing pollen tubes, hydathodes, and young xylem cells (both genes). The expression was confirmed with an anti-AtPMT1/AtPMT2 antiserum (alphaAtPMT1/2) raised against peptides conserved in AtPMT1 and AtPMT2. The physiological roles of the proteins are discussed and related to plant cell wall modifications. PMID:19969532

  2. Sucrose accumulation in mature sweet melon fruits

    International Nuclear Information System (INIS)

    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 14C-fructose + UDP-glu synthesized 14C-sucrose and efflux kinetics indicated that the 14C-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

  3. Switching the mode of sucrose utilization by Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Miletti Luiz C

    2008-02-01

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

  4. Aluminium toxicity targets PIN2 in Arabidopsis root apices: Effects on PIN2 endocytosis, vesicular recycling,and polar auxin transport

    Institute of Scientific and Technical Information of China (English)

    SHEN Hong; HOU NingYan; Markus SCHLICHT; WAN YingLang; Stefano MANCUSO; Frantisek BALUSKA

    2008-01-01

    The most obvious symptom of AI toxicity is the inhibition of root growth.However,the mechanism of AI-inhibiting root growth remains to be elucidated.In this study,auxin transport and vesicle movement of an auxin-efflux carrier (PIN2) were investigated in Arabidopsis roots in response to AI stress.Results indicated that AI inhibited the apical transport of auxin in root tips of Arabidopsis significantly.The severe inhibition was localized in the cells of transition zone,where the concentration of auxin was only 34% that of the control.Brefeldin A (BFA),an inhibitor of vesicle transport,induced the dot-like structure of PIN2 vesicle significantly.Al decreased the size of dot-like structure of PIN2 vesicles.Re-sults of real-time RT-PCR and Western-blotting analysis showed that Al increased the transcript level of PIN2 and the accumulation of PIN2 protein in horizontal direction of plasma membrane,but decreased its distribution in endosomes,suggesting that AI inhibited the transport of PIN2 vesicles from plasma membrane to endosomes.Results of cytoskeleton-depolymering drugs indicated that it was via the pathway of disruption of actin microfilaments that AI inhibited the transport of PIN2 vesicles.Exposed to AI stress,the cells of elongation zone had less AI uptake and less transport frequency of vesicles than cells of transition zone.Taken together,our results suggested that AI inhibited root growth mainly by modulating the transport of PIN2 vesicles between plasma membrane and endosomes,thus block-ing auxin transport and root growth.

  5. Arabidopsis TT19 Functions as a Carrier to Transport Anthocyanin from the Cytosol to Tonoplasts

    Institute of Scientific and Technical Information of China (English)

    Yi Sun; Hong Li; Ji-Rong Huang

    2012-01-01

    Anthocyanins are synthesized in the cytosolic surface of the endoplasmic reticulum (ER) but dominantly accumulate in the vacuole.Little is known about how anthocyanins are transported from the ER to the vacuole.Here,we provide evidence supporting that Transparent Testa 19 (TT19),a glutathione S-transferase (GST),functions as a carrier to transport cyanidin and/or anthocyanins to the tonoplast.We identified a novel tt19 mutant (tt19-7),which barely accumulates anthocyanins but produces a 36% higher level of flavonol than the wild-type (WT),from ethyl methanesulfonate mutagenized seeds.Expressing TT19-fused green fluorescence protein (GFP) in tt19-7 rescues the mutant phenotype in defective anthocyanin biosynthesis,indicating that TT19-GFP is functional.We further showed that TT19-GFP is localized not only in the cytoplasm and nuclei,but also on the tonoplast.The membrane localization of TT19-GFP was further ascertained by immunoblot analysis.In vitro assay showed that the purified recombinant TT19 increases water solubility of cyanidin (Cya) and cyanidin-3-O-glycoside (C3G).Compared with C3G,Cya can dramatically quench the intrinsic tryptophan fluorescence of TT19 to much lower levels,indicating a higher affinity of TT19 to Cya than to C3G.Isothermal titration calorimetry analysis also confirmed physical interaction between TT19 and C3G.Taken together,our data reveal molecular mechanism underlying TT19-mediated anthocyanin transportation.

  6. The exocyst complex contributes to PIN auxin efflux carrier recycling and polar auxin transport in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Drdová, Edita; Synek, Lukáš; Pečenková, Tamara; Hála, Michal; Kulich, I.; Fowler, J.E.; Murphy, A.S.; Žárský, Viktor

    2013-01-01

    Roč. 73, č. 5 (2013), s. 709-719. ISSN 0960-7412 R&D Projects: GA ČR GPP501/11/P853; GA ČR(CZ) GAP305/11/1629; GA MŠk(CZ) LC06034; GA AV ČR KJB600380802 Grant ostatní: GA MŠk(CZ) ME10033 Institutional research plan: CEZ:AV0Z50380511 Keywords : exocyst * polar auxin transport * PIN recycling Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.815, year: 2013

  7. Sucrose metabolism: gateway to diverse carbon use and sugar signaling.

    Science.gov (United States)

    Ruan, Yong-Ling

    2014-01-01

    Sucrose metabolism plays pivotal roles in development, stress response, and yield formation, mainly by generating a range of sugars as metabolites to fuel growth and synthesize essential compounds (including protein, cellulose, and starch) and as signals to regulate expression of microRNAs, transcription factors, and other genes and for crosstalk with hormonal, oxidative, and defense signaling. This review aims to capture the most exciting developments in this area by evaluating (a) the roles of key sucrose metabolic enzymes in development, abiotic stress responses, and plant-microbe interactions; (b) the coupling between sucrose metabolism and sugar signaling from extra- to intracellular spaces; (c) the different mechanisms by which sucrose metabolic enzymes could perform their signaling roles; and (d) progress on engineering sugar metabolism and transport for high yield and disease resistance. Finally, the review outlines future directions for research on sugar metabolism and signaling to better understand and improve plant performance. PMID:24579990

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

    Science.gov (United States)

    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

  9. Arabidopsis Exocyst Subcomplex Containing Subunit EXO70B1 Is Involved in Autophagy-Related Transport to the Vacuole

    Czech Academy of Sciences Publication Activity Database

    Kulich, Ivan; Pečenková, Tamara; Sekereš, J.; Smetana, Ondřej; Fendrych, Matyáš; Foissner, I.; Hoftberger, M.; Žárský, Viktor

    2013-01-01

    Roč. 14, č. 11 (2013), s. 1155-1165. ISSN 1398-9219 R&D Projects: GA ČR(CZ) GAP305/11/1629 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis * autophagy * EXO70 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.714, year: 2013

  10. Increased phosphate transport of Arabidopsis thaliana Pht1;1 by site-directed mutagenesis of tyrosine 312 may be attributed to the disruption of homomeric interactions.

    Science.gov (United States)

    Fontenot, Elena B; Ditusa, Sandra Feuer; Kato, Naohiro; Olivier, Danielle M; Dale, Renee; Lin, Wei-Yi; Chiou, Tzyy-Jen; Macnaughtan, Megan A; Smith, Aaron P

    2015-10-01

    Members of the Pht1 family of plant phosphate (Pi) transporters play vital roles in Pi acquisition from soil and in planta Pi translocation to maintain optimal growth and development. The study of the specificities and biochemical properties of Pht1 transporters will contribute to improving the current understanding of plant phosphorus homeostasis and use-efficiency. In this study, we show through split in vivo interaction methods and in vitro analysis of microsomal root tissues that Arabidopsis thaliana Pht1;1 and Pht1;4 form homomeric and heteromeric complexes. Transient and heterologous expression of the Pht1;1 variants, Pht1;1(Y312D), Pht1;1(Y312A) and Pht1;1(Y312F), was used to analyse the role of a putative Pi binding residue (Tyr 312) in Pht1;1 transporter oligomerization and function. The homomeric interaction among Pht1;1 proteins was disrupted by mutation of Tyr 312 to Asp, but not to Ala or Phe. In addition, the Pht1;1(Y312D) variant conferred enhanced Pi transport when expressed in yeast cells. In contrast, mutation of Tyr 312 to Ala or Phe did not affect Pht1;1 transport kinetics. Our study demonstrates that modifications to the Pht1;1 higher-order structure affects Pi transport, suggesting that oligomerization may serve as a regulatory mechanism for modulating Pi uptake. PMID:25754174

  11. Sucrose release from polysaccharide gels.

    Science.gov (United States)

    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

  12. HY5 regulates nitrite reductase 1 (NIR1) and ammonium transporter1;2 (AMT1;2) in Arabidopsis seedlings.

    Science.gov (United States)

    Huang, Lifen; Zhang, Hongcheng; Zhang, Huiyong; Deng, Xing Wang; Wei, Ning

    2015-09-01

    HY5 (Long Hypocotyles 5) is a key transcription factor in Arabidopsis thaliana that has a pivotal role in seedling development. Soil nitrogen is an essential macronutrient, and its uptake, assimilation and metabolism are influenced by nutrient availability and by lights. To understand the role of HY5 in nitrogen assimilation pathways, we examined the phenotype as well as the expression of selected nitrogen assimilation-related genes in hy5 mutant grown under various nitrogen limiting and nitrogen sufficient conditions, or different light conditions. We report that HY5 positively regulates nitrite reductase gene NIR1 and negatively regulates the ammonium transporter gene AMT1;2 under all nitrogen and light conditions tested, while it affects several other genes in a nitrogen supply-dependent manner. HY5 is not required for light induction of NIR1, AMT1;2 and NIA genes, but it is necessary for high level expression of NIR1 and NIA under optimal nutrient and light conditions. In addition, nitrogen deficiency exacerbates the abnormal root system of hy5. Together, our results suggest that HY5 exhibits the growth-promoting activity only when sufficient nutrients, including lights, are provided, and that HY5 has a complex involvement in nitrogen acquisition and metabolism in Arabidopsis seedlings. PMID:26259199

  13. A Bacterial Glucanotransferase Can Replace the Complex Maltose Metabolism Required for Starch to Sucrose Conversion in Leaves at Night

    DEFF Research Database (Denmark)

    Ruzanski, Christian; Smirnova, Julia; Rejzek, Martin;

    2013-01-01

    Controlled conversion of leaf starch to sucrose at night is essential for the normal growth of Arabidopsis. The conversion involves the cytosolic metabolism of maltose to hexose phosphates via an unusual, multidomain protein with 4-glucanotransferase activity, DPE2, believed to transfer glucosyl ...

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

    Science.gov (United States)

    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

  15. Sucrose compared with artificial sweeteners

    DEFF Research Database (Denmark)

    Sørensen, Lone Brinkmann; Vasilaras, Tatjana H; Astrup, Arne;

    2014-01-01

    There is a lack of appetite studies in free-living subjects supplying the habitual diet with either sucrose or artificially sweetened beverages and foods. Furthermore, the focus of artificial sweeteners has only been on the energy intake (EI) side of the energy-balance equation. The data are from a...

  16. Sucrose ingestion causes opioid analgesia

    Directory of Open Access Journals (Sweden)

    Segato F.N.

    1997-01-01

    Full Text Available The intake of saccharin solutions for relatively long periods of time causes analgesia in rats, as measured in the hot-plate test, an experimental procedure involving supraspinal components. In order to investigate the effects of sweet substance intake on pain modulation using a different model, male albino Wistar rats weighing 180-200 g received either tap water or sucrose solutions (250 g/l for 1 day or 14 days as their only source of liquid. Each rat consumed an average of 15.6 g sucrose/day. Their tail withdrawal latencies in the tail-flick test (probably a spinal reflex were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after treatment. The indexes (mean ± SEM, N = 12 for the groups receiving tap water for 1 day or 14 days, and sucrose solution for 1 day or 14 days were 0.09 ± 0.04, 0.10 ± 0.05, 0.15 ± 0.08 and 0.49 ± 0.07, respectively. One-way ANOVA indicated a significant difference (F(3,47 = 9.521, P<0.001 and the Tukey multiple comparison test (P<0.05 showed that the analgesia index of the 14-day sucrose-treated animals differed from all other groups. Naloxone-treated rats (N = 7 receiving sucrose exhibited an analgesia index of 0.20 ± 0.10 while rats receiving only sucrose (N = 7 had an index of 0.68 ± 0.11 (t = 0.254, 10 degrees of freedom, P<0.03. This result indicates that the analgesic effect of sucrose depends on the time during which the solution is consumed and extends the analgesic effects of sweet substance intake, such as saccharin, to a model other than the hot-plate test, with similar results. Endogenous opioids may be involved in the central regulation of the sweet substance-produced analgesia.

  17. Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis

    OpenAIRE

    Liang Li; Hao Wang; Jorge Gago; Haiying Cui; Zhengjiang Qian; Naomi Kodama; Hongtao Ji; Shan Tian; Dan Shen; Yanjuan Chen; Fengli Sun; Zhonglan Xia; Qing Ye; Wei Sun; Jaume Flexas

    2015-01-01

    Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO...

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

    Science.gov (United States)

    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…

  19. 21 CFR 184.1854 - Sucrose.

    Science.gov (United States)

    2010-04-01

    ... Substances Affirmed as GRAS § 184.1854 Sucrose. (a) Sucrose (C12H22O11, CAS Reg. No. 57-50-11-1) sugar, cane 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. Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida.

    Science.gov (United States)

    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

  1. Magnetostructural study of iron sucrose

    International Nuclear Information System (INIS)

    Magnetic and structural analyses have been performed on an iron sucrose complex used as a haematinic agent. The system contains two-line ferrihydrite particles of about 5 nm that are superparamagnetic above approximately 50 K. The observed low-temperature magnetic dynamics of this compound is closer to simple models than in the case of other iron-containing drugs for intravenous use like iron dextran

  2. Characterization of an AtCCX5 gene from Arabidopsis thaliana that involves in high-affinity K+ uptake and Na+ transport in yeast

    International Nuclear Information System (INIS)

    Highlights: → The AtCCX5 protein coding a putative cation calcium exchanger was characterized. → AtCCX5 expressed in yeast was localized in the plasma membrane and nuclear periphery. → AtCCX5 protein did not show the same transport properties as the CAXs. → AtCCX5 protein involves in mediating high-affinity K+ uptake in yeast. → AtCCX5 protein also involves in Na+ transport in yeast. -- Abstract: The gene for a putative cation calcium exchanger (CCX) from Arabidopsis thaliana, AtCCX5, was cloned and its function was analyzed in yeast. Green fluorescent protein-tagged AtCCX5 expressed in yeast was localized in the plasma membrane and nuclear periphery. The yeast transformants expressing AtCCX5 were created and their growth in the presence of various cations (K+, Na+, Ca2+, Mg2+, Fe2+, Cu2+, Co2+, Cd2+, Mn2+, Ba2+, Ni2+, Zn2+, and Li+) were analyzed. AtCCX5 expression was found to affect the response to K+ and Na+ in yeast. The AtCCX5 transformant also showed a little better growth to Zn2+. The yeast mutant 9.3 expressing AtCCX5 restored growth of the mutant on medium with low K+ (0.5 mM), and also suppressed its Na+ sensitivity. Ion uptake experiments showed that AtCCX5 mediated relatively high-affinity K+ uptake and was also involved in Na+ transport in yeast. Taken together, these findings suggest that the AtCCX5 is a novel transport protein involves in mediating high-affinity K+ uptake and Na+ transport in yeast.

  3. Quantitative and Functional Phosphoproteomic Analysis Reveals that Ethylene Regulates Water Transport via the C-Terminal Phosphorylation of Aquaporin PIP2;1 in Arabidopsis.

    Science.gov (United States)

    Qing, Dongjin; Yang, Zhu; Li, Mingzhe; Wong, Wai Shing; Guo, Guangyu; Liu, Shichang; Guo, Hongwei; Li, Ning

    2016-01-01

    Ethylene participates in the regulation of numerous cellular events and biological processes, including water loss, during leaf and flower petal wilting. The diverse ethylene responses may be regulated via dynamic interplays between protein phosphorylation/dephosphorylation and ubiquitin/26S proteasome-mediated protein degradation and protease cleavage. To address how ethylene alters protein phosphorylation through multi-furcated signaling pathways, we performed a (15)N stable isotope labelling-based, differential, and quantitative phosphoproteomics study on air- and ethylene-treated ethylene-insensitive Arabidopsis double loss-of-function mutant ein3-1/eil1-1. Among 535 non-redundant phosphopeptides identified, two and four phosphopeptides were up- and downregulated by ethylene, respectively. Ethylene-regulated phosphorylation of aquaporin PIP2;1 is positively correlated with the water flux rate and water loss in leaf. Genetic studies in combination with quantitative proteomics, immunoblot analysis, protoplast swelling/shrinking experiments, and leaf water loss assays on the transgenic plants expressing both the wild-type and S280A/S283A-mutated PIP2;1 in the both Col-0 and ein3eil1 genetic backgrounds suggest that ethylene increases water transport rate in Arabidopsis cells by enhancing S280/S283 phosphorylation at the C terminus of PIP2;1. Unknown kinase and/or phosphatase activities may participate in the initial up-regulation independent of the cellular functions of EIN3/EIL1. This finding contributes to our understanding of ethylene-regulated leaf wilting that is commonly observed during post-harvest storage of plant organs. PMID:26476206

  4. Tissue-specific root ion profiling reveals essential roles of the CAX and ACA calcium transport systems in response to hypoxia in Arabidopsis.

    Science.gov (United States)

    Wang, Feifei; Chen, Zhong-Hua; Liu, Xiaohui; Colmer, Timothy David; Zhou, Meixue; Shabala, Sergey

    2016-06-01

    Waterlogging is a major abiotic stress that limits the growth of plants. The crucial role of Ca(2+) as a second messenger in response to abiotic and biotic stimuli has been widely recognized in plants. However, the physiological and molecular mechanisms of Ca(2+) distribution within specific cell types in different root zones under hypoxia is poorly understood. In this work, whole-plant physiological and tissue-specific Ca(2+) changes were studied using several ACA (Ca(2+)-ATPase) and CAX (Ca(2+)/proton exchanger) knock-out Arabidopsis mutants subjected to waterlogging treatment. In the wild-type (WT) plants, several days of hypoxia decreased the expression of ACA8, CAX4, and CAX11 by 33% and 50% compared with the control. The hypoxic treatment also resulted in an up to 11-fold tissue-dependent increase in Ca(2+) accumulation in root tissues as revealed by confocal microscopy. The increase was much higher in stelar cells in the mature zone of Arabidopsis mutants with loss of function for ACA8, ACA11, CAX4, and CAX11 In addition, a significantly increased Ca(2+) concentration was found in the cytosol of stelar cells in the mature zone after hypoxic treatment. Three weeks of waterlogging resulted in dramatic loss of shoot biomass in cax11 plants (67% loss in shoot dry weight), while in the WT and other transport mutants this decline was only 14-22%. These results were also consistent with a decline in leaf chlorophyll fluorescence (F v/F m). It is suggested that CAX11 plays a key role in maintaining cytosolic Ca(2+) homeostasis and/or signalling in root cells under hypoxic conditions. PMID:26889007

  5. The Half-Size ABC Transporter FOLDED PETALS 2/ABCG13 Is Involved in Petal Elongation through Narrow Spaces in Arabidopsis thaliana Floral Buds

    Directory of Open Access Journals (Sweden)

    Seiji Takeda

    2014-08-01

    Full Text Available Flowers are vital for attracting pollinators to plants and in horticulture for humans. Petal morphogenesis is a central process of floral development. Petal development can be divided into three main processes: the establishment of organ identity in a concentric pattern, primordia initiation at fixed positions within a whorl, and morphogenesis, which includes petal elongation through the narrow spaces within the bud. Here, we show that the FOLDED PETALS 2 (FOP2 gene, encoding a member of the half-size ATP binding cassette (ABC transporter family ABCG13, is involved in straight elongation of petals in Arabidopsis thaliana. In fop2 mutants, flowers open with folded petals, instead of straight-elongated ones found in the wild type. The epicuticular nanoridge structures are absent in many abaxial epidermal cells of fop2 petals, and surgical or genetic generation of space in young fop2 buds restores the straight elongation of petals, suggesting that the physical contact of sepals and petals causes the petal folding. Similar petal folding has been reported in the fop1 mutant, and the petals of fop2 fop1 double mutants resemble those of both the fop1 and fop2 single mutants, although the epidermal structure and permeability of the petal surface is more affected in fop2. Our results suggest that synthesis and transport of cutin or wax in growing petals play an important role for their smooth elongation through the narrow spaces of floral buds.

  6. Arabidopsis CDS blastp result: AK288065 [KOME

    Lifescience Database Archive (English)

    Full Text Available al to sulfate tansporter Sultr1;3 [Arabidopsis thaliana] GI:10716805; contains Pfam profile PF00916: Sulfate... transporter family; contains Pfam profile PF01740: STAS domain; contains TIGRfam profile TIGR00815: sulfate permease 1e-145 ...

  7. The impact of the absence of aliphatic glucosinolates on water transport under salt stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Mcarmen eMartinez-Ballesta

    2015-07-01

    Full Text Available Members of the Brassicaceae are known for their contents of nutrients and health-promoting phytochemicals, including glucosinolatesExposure to salinity increases the levels of several of these compounds, but their role in abiotic stress response is unclear. The effect of aliphatic glucosinolates on plant water balance and growth under salt stress, involving aquaporins, was investigated by means of Arabidopsis thaliana mutants impaired in aliphatic glucosinolate biosynthesis, which is controlled by two transcription factors: Myb28 and Myb29. The double mutant myb28myb29, completely lacking aliphatic glucosinolates, was compared to wild type Col-0 (WT and the single mutant myb28. A greater reduction in the hydraulic conductivity of myb28myb29 was observed under salt stress, when compared to the WT and myb28; this correlated with the abundance of both PIP1 and PIP2 aquaporin subfamilies. Also, changes in root architecture in response to salinity were genotype dependent. Treatment with NaCl altered glucosinolates biosynthesis in a similar way in WT and the single mutant and differently in the double mutant. The results indicate that short-chain aliphatic glucosinolates may contribute to water saving under salt stress

  8. Elucidating the Roles of Transport Processes in Glucosinolate Distribution

    DEFF Research Database (Denmark)

    Madsen, Svend Roesen

    Glucosinolates are plant defense compounds characteristic of the economically important plant family of Brassicaceae, which comprises crops as oilseed rape, cabbage, broccoli and the model plant Arabidopsis thaliana (Arabidopsis). Recently, two Arabidopsis glucosinolate transporters, GTR1 and GTR2...

  9. Sucrose synthesis in gamma irradiated sweet potato

    International Nuclear Information System (INIS)

    Effect of α-irradiation carbohydrate metabolism was examined to elucidate mechanism of sucrose accumulation in sweet potato (SP). Enzymes examined were: β-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 240C. Phosphorylase and phosphoglucomutases specific activities reached 2.4 and 1.8 folds, respectively compared to control SP. β-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)

  10. Production of 16% ethanol from 35% sucrose

    International Nuclear Information System (INIS)

    A strain of Saccharomyces cerevisiae, which showed marked fermentation activity, ethanol and temperature tolerance and good flocculation ability, was selected for ethanol production. A stuck fermentation occurred at sucrose concentration of 25%. Increasing the yeast inoculum volume from 3% to 6% showed positive effects on fermentation from 25% sucrose. The ratio of added nitrogen to sucrose, which gave the best results (for the selected yeast strain), was determined. It was concluded that this ratio (nitrogen as ammonium sulphate at a rate of 5 mg g-1 of consumed sucrose) is constant at various sugar concentrations. Addition of nitrogen at this ratio produced 11.55% ethanol with complete consumption of 25% sucrose after 48 h of fermentation. However fermentation of 30% sucrose at the above optimum conditions was not complete. Addition of yeast extract at a level of 6 g l-1 together with thiamine at a level of 0.2 g l-1 led to complete utilization of 30% sucrose with resultant 14% ethanol production. However the selected yeast strain was not able to ferment 35% sucrose at the same optimum conditions. Addition of air at a rate of 150 dm3 min-1 m3 of reactor volume during the first 12 h of fermentation led to complete consumption of 35% sucrose and 16% ethanol was produced. This was approximately the theoretical maximum for ethanol production.

  11. The signal transducer NPH3 integrates the phototropin1 photosensor with PIN2-based polar auxin transport in Arabidopsis root phototropism.

    Science.gov (United States)

    Wan, Yinglang; Jasik, Jan; Wang, Li; Hao, Huaiqing; Volkmann, Dieter; Menzel, Diedrik; Mancuso, Stefano; Baluška, František; Lin, Jinxing

    2012-02-01

    Under blue light (BL) illumination, Arabidopsis thaliana roots grow away from the light source, showing a negative phototropic response. However, the mechanism of root phototropism is still unclear. Using a noninvasive microelectrode system, we showed that the BL sensor phototropin1 (phot1), the signal transducer NONPHOTOTROPIC HYPOCOTYL3 (NPH3), and the auxin efflux transporter PIN2 were essential for BL-induced auxin flux in the root apex transition zone. We also found that PIN2-green fluorescent protein (GFP) localized to vacuole-like compartments (VLCs) in dark-grown root epidermal and cortical cells, and phot1/NPH3 mediated a BL-initiated pathway that caused PIN2 redistribution to the plasma membrane. When dark-grown roots were exposed to brefeldin A (BFA), PIN2-GFP remained in VLCs in darkness, and BL caused PIN2-GFP disappearance from VLCs and induced PIN2-GFP-FM4-64 colocalization within enlarged compartments. In the nph3 mutant, both dark and BL BFA treatments caused the disappearance of PIN2-GFP from VLCs. However, in the phot1 mutant, PIN2-GFP remained within VLCs under both dark and BL BFA treatments, suggesting that phot1 and NPH3 play different roles in PIN2 localization. In conclusion, BL-induced root phototropism is based on the phot1/NPH3 signaling pathway, which stimulates the shootward auxin flux by modifying the subcellular targeting of PIN2 in the root apex transition zone. PMID:22374399

  12. Cucumber metal transport protein MTP8 confers increased tolerance to manganese when expressed in yeast and Arabidopsis thaliana

    OpenAIRE

    Migocka, Magdalena; Papierniak, Anna; Maciaszczyk-Dziubińska, Ewa; Poździk, Piotr; Posyniak, Ewelina; Garbiec, Arnold; Filleur, Sophie

    2014-01-01

    The family of genes encoding metal tolerance proteins (MTPs) in cucumber is identified and described. The cucumber Mn transporter CsMTP8 is biochemically and functionally characterized in yeast and A. thaliana.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Cadmium-inducible expression of the ABC-type transporter AtABCC3 increases phytochelatin-mediated cadmium tolerance in Arabidopsis

    Science.gov (United States)

    Brunetti, Patrizia; Zanella, Letizia; De Paolis, Angelo; Di Litta, Davide; Cecchetti, Valentina; Falasca, Giuseppina; Barbieri, Maurizio; Altamura, Maria Maddalena; Costantino, Paolo; Cardarelli, Maura

    2015-01-01

    The heavy metal cadmium (Cd) is a widespread environmental contaminant with harmful effects on living cells. In plants, phytochelatin (PC)-dependent Cd detoxification requires that PC–Cd complexes are transported into vacuoles. Here, it is shown that Arabidopsis thaliana seedlings defective in the ABCC transporter AtABCC3 (abcc3) have an increased sensitivity to different Cd concentrations, and that seedlings overexpressing AtABCC3 (AtABCC3ox) have an increased Cd tolerance. The cellular distribution of Cd was analysed in protoplasts from abcc3 mutants and AtABCC3 overexpressors grown in the presence of Cd, by means of the Cd-specific fluorochromes 5-nitrobenzothiazole coumarin (BTC-5N) and Leadmium™ Green AM dye. This analysis revealed that Cd is mostly localized in the cytosol of abcc3 mutant protoplasts whereas there is an increase in vacuolar Cd in protoplasts from AtABCC3ox plants. Overexpression of AtABCC3 in cad1-3 mutant seedlings defective in PC production and in plants treated with l-buthionine sulphoximine (BSO), an inhibitor of PC biosynthesis, had no effect on Cd tolerance, suggesting that AtABCC3 acts via PCs. In addition, overexpression of AtABCC3 in atabcc1 atabcc2 mutant seedlings defective in the Cd transporters AtABCC1 and AtABCC2 complements the Cd sensitivity of double mutants, but not in the presence of BSO. Accordingly, the level of AtABCC3 transcript in wild type seedlings was lower than that of AtABCC1 and AtABCC2 in the absence of Cd but higher after Cd exposure, and even higher in atabcc1 atabcc2 mutants. The results point to AtABCC3 as a transporter of PC–Cd complexes, and suggest that its activity is regulated by Cd and is co-ordinated with the activity of AtABCC1/AtABCC2. PMID:25900618

  15. Cadmium-inducible expression of the ABC-type transporter AtABCC3 increases phytochelatin-mediated cadmium tolerance in Arabidopsis.

    Science.gov (United States)

    Brunetti, Patrizia; Zanella, Letizia; De Paolis, Angelo; Di Litta, Davide; Cecchetti, Valentina; Falasca, Giuseppina; Barbieri, Maurizio; Altamura, Maria Maddalena; Costantino, Paolo; Cardarelli, Maura

    2015-07-01

    The heavy metal cadmium (Cd) is a widespread environmental contaminant with harmful effects on living cells. In plants, phytochelatin (PC)-dependent Cd detoxification requires that PC-Cd complexes are transported into vacuoles. Here, it is shown that Arabidopsis thaliana seedlings defective in the ABCC transporter AtABCC3 (abcc3) have an increased sensitivity to different Cd concentrations, and that seedlings overexpressing AtABCC3 (AtABCC3ox) have an increased Cd tolerance. The cellular distribution of Cd was analysed in protoplasts from abcc3 mutants and AtABCC3 overexpressors grown in the presence of Cd, by means of the Cd-specific fluorochromes 5-nitrobenzothiazole coumarin (BTC-5N) and Leadmium™ Green AM dye. This analysis revealed that Cd is mostly localized in the cytosol of abcc3 mutant protoplasts whereas there is an increase in vacuolar Cd in protoplasts from AtABCC3ox plants. Overexpression of AtABCC3 in cad1-3 mutant seedlings defective in PC production and in plants treated with l-buthionine sulphoximine (BSO), an inhibitor of PC biosynthesis, had no effect on Cd tolerance, suggesting that AtABCC3 acts via PCs. In addition, overexpression of AtABCC3 in atabcc1 atabcc2 mutant seedlings defective in the Cd transporters AtABCC1 and AtABCC2 complements the Cd sensitivity of double mutants, but not in the presence of BSO. Accordingly, the level of AtABCC3 transcript in wild type seedlings was lower than that of AtABCC1 and AtABCC2 in the absence of Cd but higher after Cd exposure, and even higher in atabcc1 atabcc2 mutants. The results point to AtABCC3 as a transporter of PC-Cd complexes, and suggest that its activity is regulated by Cd and is co-ordinated with the activity of AtABCC1/AtABCC2. PMID:25900618

  16. Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana.

    Science.gov (United States)

    Lin, Ya-Fen; Hassan, Zeshan; Talukdar, Sangita; Schat, Henk; Aarts, Mark G M

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5' deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading. PMID:26930473

  17. Expression of the ZNT1 Zinc Transporter from the Metal Hyperaccumulator Noccaea caerulescens Confers Enhanced Zinc and Cadmium Tolerance and Accumulation to Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ya-Fen Lin

    Full Text Available Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis. We examined if the NcZNT1 function contributes to the metal hyperaccumulation of N. caerulescens. NcZNT1 was found to be a plasma-membrane located metal transporter. Constitutive overexpression of NcZNT1 in A. thaliana conferred enhanced tolerance to exposure to excess Zn and Cd supply, as well as increased accumulation of Zn and Cd and induction of the Fe deficiency response, when compared to non-transformed wild-type plants. Promoters of both genes were induced by Zn deficiency in roots and shoots of A. thaliana. In A. thaliana, the AtZIP4 and NcZNT1 promoters were mainly active in cortex, endodermis and pericycle cells under Zn deficient conditions. In N. caerulescens, the promoters were active in the same tissues, though the activity of the NcZNT1 promoter was higher and not limited to Zn deficient conditions. Common cis elements were identified in both promoters by 5' deletion analysis. These correspond to the previously determined Zinc Deficiency Responsive Elements found in A. thaliana to interact with two redundantly acting transcription factors, bZIP19 and bZIP23, controlling the Zn deficiency response. In conclusion, these results suggest that NcZNT1 is an important factor in contributing to Zn and Cd hyperaccumulation in N. caerulescens. Differences in cis- and trans-regulators are likely to account for the differences in expression between A. thaliana and N. caerulescens. The high, constitutive NcZNT1 expression in the stele of N. caerulescens roots implicates its involvement in long distance root-to-shoot metal transport by maintaining a Zn/Cd influx into cells responsible for xylem loading.

  18. Aluminum-activated citrate and malate transporters encoded by distinct Al tolerance genes function independently in Arabidopsis

    Science.gov (United States)

    Aluminum (Al) -activated malate and citrate exudation from roots plays an important role in conferring Al tolerance to many plant species. Here, we report on the identification and characterization of AtMATE, the gene encoding an Al-activated root citrate efflux transporter that functions in Arabid...

  19. Identification of a crucial histidine involved in metal transport activity in the Arabidopsis cation/H(+) exchanger CAX1

    Science.gov (United States)

    In plants, yeast and bacteria, cation/H(+) exchangers (CAXs), have been shown to translocate Ca(2+) and other metals. The best characterized of these related transporters is the plant vacuolar-localized CAX1. We used site-directed mutagenesis to assess the impact of altering the seven histidine re...

  20. Intronic Sequence Regulates Sugar-Dependent Expression of Arabidopsis thaliana Production of Anthocyanin Pigment-1/MYB75

    Science.gov (United States)

    Broeckling, Bettina E.; Watson, Ruth A.; Steinwand, Blaire; Bush, Daniel R.

    2016-01-01

    Sucrose-specific regulation of gene expression is recognized as an important signaling response, distinct from glucose, which serves to modulate plant growth, metabolism, and physiology. The Arabidopsis MYB transcription factor Production of Anthocyanin Pigment-1 (PAP1) plays a key role in anthocyanin biosynthesis and expression of PAP1 is known to be regulated by sucrose. Sucrose treatment of Arabidopsis seedlings led to a 20-fold induction of PAP1 transcript, which represented a 6-fold increase over levels in glucose-treated seedlings. The PAP1 promoter was not sufficient for conferring a sucrose response to a reporter gene and did not correctly report expression of PAP1 in plants. Although we identified 3 putative sucrose response elements in the PAP1 gene, none were found to be necessary for this response. Using deletion analysis, we identified a 90 bp sequence within intron 1 of PAP1 that is necessary for the sucrose response. This sequence was sufficient for conferring a sucrose response to a minimal promoter: luciferase reporter when present in multiple copies upstream of the promoter. This work lays the foundation for dissecting the sucrose signaling pathway of PAP1 and contributes to understanding the interplay between sucrose signaling, anthocyanin biosynthesis, and stress responses. PMID:27248141

  1. STP10 encodes a high-affinity monosaccharide transporter and is induced under low-glucose conditions in pollen tubes of Arabidopsis

    OpenAIRE

    Rottmann, Theresa; Zierer, Wolfgang; Subert, Christa; Sauer, Norbert; Stadler, Ruth

    2016-01-01

    Highlight STP10 is part of a high-affinity monosaccharide uptake system in the plasma membrane of pollen tubes of Arabidopsis. It is down-regulated under high-glucose conditions, possibly through the hexokinase pathway.

  2. The Arabidopsis concentration-dependent influx/efflux transporter ABCB4 regulates cellular auxin levels in the root epidermis

    Czech Academy of Sciences Publication Activity Database

    Kubeš, Martin; Yang, H.; Richter, G.L.; Cheng, Y.; Młodzińska, E.; Wang, X.; Blakeslee, J.J.; Carraro, N.; Petrášek, Jan; Zažímalová, Eva; Hoyerová, Klára; Ann Peer, W.; Murphy, A. S.

    2012-01-01

    Roč. 69, č. 4 (2012), s. 640-654. ISSN 0960-7412 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GAP305/11/0797 Institutional research plan: CEZ:AV0Z50380511 Keywords : auxin * auxin transporters * ATP-binding cassette B4 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.582, year: 2012

  3. Ectopic expression of Arabidopsis glycosyltransferase UGT85A5 enhances salt stress tolerance in tobacco.

    Directory of Open Access Journals (Sweden)

    Yan-Guo Sun

    Full Text Available Abiotic stresses greatly influence plant growth and productivity. While glycosyltransferases are widely distributed in plant kingdom, their biological roles in response to abiotic stresses are largely unknown. In this study, a novel Arabidopsis glycosyltransferase gene UGT85A5 was identified as significantly induced by salt stress. Ectopic expression of UGT85A5 in tobacco enhanced the salt stress tolerance in the transgenic plants. There were higher seed germination rates, better plant growth and less chlorophyll loss in transgenic lines compared to wild type plants under salt stress. This enhanced tolerance of salt stress was correlated with increased accumulations of proline and soluble sugars, but with decreases in malondialdehyde accumulation and Na(+/K(+ ratio in UGT85A5-expressing tobacco. Furthermore, during salt stress, expression of several carbohydrate metabolism-related genes including those for sucrose synthase, sucrose-phosphate synthase, hexose transporter and a group2 LEA protein were obviously upregulated in UGT85A5-expressing transgenic plants compared with wild type controls. Thus, these findings suggest a specific protective role of this glycosyltransferase against salt stress and provide a genetic engineering strategy to improve salt tolerance of crops.

  4. Omics analysis of high-energy Arabidopsis thaliana

    OpenAIRE

    Liang, Chao; 梁超

    2014-01-01

    Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2) is a phosphatase dually targeted to both chloroplasts and mitochondria. Overexpression (OE) of AtPAP2 in Arabidopsis thaliana was reported to speed up plant growth and promote flowering, seed yield and biomass at maturity in a previous study. Under long-day (16 hours light at 22°C / 8 hours dark at 18°C) growth conditions, the leaves of 20-day-old OE lines contained significant higher sucrose and glucose than the wild-type (WT) plants, r...

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

    Science.gov (United States)

    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

  6. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

    Institute of Scientific and Technical Information of China (English)

    Yu Mei; Wen-Jing Jia; Yu-Jia Chu; Hong-Wei Xue

    2012-01-01

    Phosphatidylinositol monophosphate 5-kinase(PIP5K)catalyzes the synthesis of PI-4,5-bisphosphate(PtdIns(4,5)P2)by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring,and is involved in regulating multiple developmental processes and stress responses.We here report on the functional characterization of Arabidopsis PIP5K2,which is expressed during lateral root initiation and elongation,and whose expression is enhanced by exogenous auxin.The knockout mutant pip5k2 shows reduced lateral root formation,which could be recovered with exogenous auxin,and interestingly,delayed root gravity response that could not be recovered with exogenous auxin.Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2.In addition,analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P2 reduction,which hence results in suppressed cycling of PIN proteins(PIN2 and 3),and delayed redistribution of PIN2 and auxin under gravistimulation in pipSk2 roots.On the contrary,PtdIns(4,5)P2 significantly enhanced the vesicle trafficking and cycling of PIN proteins.These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response,and reveal a critical role of PIP5K2/Ptdlns(4,5)P2 in root development through regulation of PIN proteins,providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response,and new insights into the control of polar auxin transport.

  7. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins.

    Science.gov (United States)

    Mei, Yu; Jia, Wen-Jing; Chu, Yu-Jia; Xue, Hong-Wei

    2012-03-01

    Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5)P(2)) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k2 shows reduced lateral root formation, which could be recovered with exogenous auxin, and interestingly, delayed root gravity response that could not be recovered with exogenous auxin. Crossing with the DR5-GUS marker line and measurement of free IAA content confirmed the reduced auxin accumulation in pip5k2. In addition, analysis using the membrane-selective dye FM4-64 revealed the decelerated vesicle trafficking caused by PtdIns(4,5)P(2) reduction, which hence results in suppressed cycling of PIN proteins (PIN2 and 3), and delayed redistribution of PIN2 and auxin under gravistimulation in pip5k2 roots. On the contrary, PtdIns(4,5)P(2) significantly enhanced the vesicle trafficking and cycling of PIN proteins. These results demonstrate that PIP5K2 is involved in regulating lateral root formation and root gravity response, and reveal a critical role of PIP5K2/PtdIns(4,5)P(2) in root development through regulation of PIN proteins, providing direct evidence of crosstalk between the phosphatidylinositol signaling pathway and auxin response, and new insights into the control of polar auxin transport. PMID:21894193

  8. IDENTIFICATION AND CHARACTERIZATION OF THE SUCROSE SYNTHASE 2 GENE (Sus2 IN DURUM WHEAT

    Directory of Open Access Journals (Sweden)

    Mariateresa eVolpicella

    2016-03-01

    Full Text Available Sucrose transport is the central system for the allocation of carbon resources in vascular plants. Sucrose synthase, 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 sucrose synthase 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 modelling approaches. The combined results of SUS2 expression and activity levels were then considered in the light of their possible involvement in starch yield.

  9. Sucrose- and Fructose-Specific Effects on the Transcriptome of Streptococcus mutans, as Determined by RNA Sequencing.

    Science.gov (United States)

    Zeng, Lin; Burne, Robert A

    2016-01-01

    Recent genome-scale studies have begun to establish the scope and magnitude of the impacts of carbohydrate source and availability on the regulation of gene expression in bacteria. The effects of sugars on gene expression are particularly profound in a group of lactic acid bacteria that rely almost entirely on their saccharolytic activities for energy production and growth. For Streptococcus mutans, the major etiologic agent of human dental caries, sucrose is the carbohydrate that contributes in the most significant manner to establishment, persistence, and virulence of the organism. However, because this organism produces multiple extracellular sucrolytic enzymes that can release hexoses from sucrose, it has not been possible to study the specific effects of sucrose transport and metabolism on gene expression in the absence of carbohydrates that by themselves can elicit catabolite repression and induce expression of multiple genes. By employing RNA deep-sequencing (RNA-Seq) technology and mutants that lacked particular sucrose-metabolizing enzymes, we compared the transcriptomes of S. mutans bacteria growing on glucose, fructose, or sucrose as the sole carbohydrate source. The results provide a variety of new insights into the impact of sucrose transport and metabolism by S. mutans, including the likely expulsion of fructose after sucrose internalization and hydrolysis, and identify a set of genes that are differentially regulated by sucrose versus fructose. The findings significantly enhance our understanding of the genetics and physiology of this cariogenic pathogen. PMID:26475108

  10. Cytokinins Enhance Sugar-Induced Anthocyanin Biosynthesis in Arabidopsis

    OpenAIRE

    Das, Prasanta Kumar; Shin, Dong Ho; Choi, Sang-Bong; Yoo, Sang-Dong; Choi, Giltsu; Park, Youn-II

    2012-01-01

    In higher plants, the regulation of anthocyanin synthesis by various factors including light, sugars and hormones is mediated by numerous regulatory factors acting at the transcriptional level. Here, the association between sucrose and the plant hormone, cytokinin, in the presence of light was investigated to elucidate cytokinin signaling cascades leading to the transcriptional activation of anthocyanin biosynthesis genes in Arabidopsis seedlings. We showed that cytokinin enhances anthocyanin...

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

    Science.gov (United States)

    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. PMID:12866615

  12. Effect of High Temperature on Sucrose Content and Sucrose Cleaving Enzyme Activity in Rice Grain During the Filling Stage

    Institute of Scientific and Technical Information of China (English)

    LI Tian; LIU Qi-hua; Ryu OHSUGI; Tohru YAMAGISHI; Haruto SASAKI

    2006-01-01

    Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.

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

    Science.gov (United States)

    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

  14. Kaempferol 3-O-rhamnoside-7-O-rhamnoside is an endogenous flavonol inhibitor of polar auxin transport in Arabidopsis shoots

    Czech Academy of Sciences Publication Activity Database

    Yin, R.H.; Han, K.; Heller, W.; Albert, A.; Dobrev, Petre; Zažímalová, Eva; Schaffner, A.R.

    2014-01-01

    Roč. 201, č. 2 (2014), s. 466-475. ISSN 1469-8137 R&D Projects: GA ČR(CZ) GAP305/11/0797 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * flavonol biosynthesis * flavonol glycoside Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.373, year: 2013

  15. THE PROBABLE HAZARDS OF SUCROSE IN MAN

    Directory of Open Access Journals (Sweden)

    H. Mohammadiha

    1974-08-01

    Full Text Available The effect of dietary sucrose on DNA formation in rat liver and kidney compared with that of starch was studied. Male, weanling rats were fed for 6 and 14 days on diets containing 68% 'sucrose or 68% starch, and liver and kidneys were examined for 1ilie amount and rate of formation of DNA; and also for content of fat, protein, and moisture. Food intake and weight gain were estimated. Sucrose fed animals had heavier liver and kidneys than starch fed animals. Food intake and weight gain were similar on both diets. The enlargement of the liver after six days was mainly due to increase in1cell number calculated from DNA content. Whereas, after 14 days, the enlargement was mostly due to incensement of cell size. The proportion of protein and moisture in the liver of sucrose fed animals was less than in the starch fed ones, whereas fat content was 25'% higher. Sucrose feeding had no effect in six days on weight of kidneys, but after 14 days heavier kidneys were produced. Exemption of cortex showed no difference in cell number or cell size. Twenty-four hours before killing the animals were injected intraperitoneally with H3 thymidine. Radioactive count was too low, the results too variable for any conclusions to be drawn.

  16. Isotachophoresis of proteins in sucrose density gradients.

    Science.gov (United States)

    Acevedo, F

    1993-10-01

    The separation of proteins from human serum by isotachophoresis in sucrose density gradients, with mixtures of discrete amphoteric substances as spacers, is described. Open columns and columns with a dialysis membrane to hold the sucrose gradients were used. A simple algorithm based on the Kohlrausch function was used to calculate the amount of each spacer. The pH gradients generated in open columns were found to be in agreement with the calculations. The load was up to two gram proteins. The analysis of the fractions obtained after the separation showed a distribution of components similar to as analytical isotachophoresis. It is concluded that sucrose density gradients are suitable as supporting media for the preparative separation of proteins by isotachophoresis. The high resolution attained and the possibility of scaling-up the separation systems are major advantages of this system. In addition, the sample is easily and completely recoverable. PMID:8125049

  17. Transcriptomic analysis of Arabidopsis overexpressing flowering locus T driven by a meristem-specific promoter that induces early flowering.

    Science.gov (United States)

    Duplat-Bermúdez, L; Ruiz-Medrano, R; Landsman, D; Mariño-Ramírez, L; Xoconostle-Cázares, B

    2016-08-10

    Here we analyzed in leaves the effect of FT overexpression driven by meristem-specific KNAT1 gene homolog of Arabidopsis thaliana (Lincoln et al., 1994; Long et al., 1996) on the transcriptomic response during plant development. Our results demonstrated that meristematic FT overexpression generates a phenotype with an early flowering independent of photoperiod when compared with wild type (WT) plants. Arabidopsis FT-overexpressor lines (AtFTOE) did not show significant differences compared with WT lines neither in leaf number nor in rosette diameter up to day 21, when AtFTOE flowered. After this period AtFTOE plants started flower production and no new rosette leaves were produced. Additionally, WT plants continued on vegetative stage up to day 40, producing 12-14 rosette leaves before flowering. Transcriptomic analysis of rosette leaves studied by sequencing Illumina RNA-seq allowed us to determine the differential expression in mature leaf rosette of 3652 genes, being 626 of them up-regulated and 3026 down-regulated. Overexpressed genes related with flowering showed up-regulated transcription factors such as MADS-box that are known as flowering markers in meristem and which overexpression has been related with meristem identity preservation and the transition from vegetative to floral stage. Genes related with sugar transport have shown a higher demand of monosaccharides derived from the hydrolysis of sucrose to glucose and probably fructose, which can also be influenced by reproductive stage of AtFTOE plants. PMID:27154816

  18. Transcriptomic analysis of Arabidopsis overexpressing flowering locus T driven by a meristem-specific promoter that induces early flowering

    Science.gov (United States)

    Duplat-Bermúdez, L.; Ruiz-Medrano, R.; Landsman, D.; Mariño-Ramírez, L.; Xoconostle-Cázares, B.

    2016-01-01

    Here we analyzed in leaves the effect of FT overexpression driven by meristem-specific KNAT1 gene homolog of Arabidopsis thaliana (Lincoln et al., 1994; Long et al., 1996) on the transcriptomic response during plant development. Our results demonstrated that meristematic FT overexpression generates a phenotype with an early flowering independent of photoperiod when compared with wild type (WT) plants. Arabidopsis FT-overexpressor lines (AtFTOE) did not show significant differences compared with WT lines neither in leaf number nor in rosette diameter up to day 21, when AtFTOE flowered. After this period AtFTOE plants started flower production and no new rosette leaves were produced. Additionally, WT plants continued on vegetative stage up to day 40, producing 12–14 rosette leaves before flowering. Transcriptomic analysis of rosette leaves studied by sequencing Illumina RNA-seq allowed us to determine the differential expression in mature leaf rosette of 3652 genes, being 626 of them up-regulated and 3026 down-regulated. Overexpressed genes related with flowering showed up-regulated transcription factors such as MADS-box that are known as flowering markers in meristem and which overexpression has been related with meristem identity preservation and the transition from vegetative to floral stage. Genes related with sugar transport have shown a higher demand of monosaccharides derived from the hydrolysis of sucrose to glucose and probably fructose, which can also be influenced by reproductive stage of AtFTOE plants. PMID:27154816

  19. Translocation of 14C-sucrose from mesophyll to vein and stem bark in mulberry plant

    International Nuclear Information System (INIS)

    One-year-old seedlings of mulberry, the variety of Shinichinose, were used to fix 14CO2 for 10 minutes under light of 18,000 lux at 28 deg C. Photosynthesis was continued after that in the air not containing 14CO2 . The specimens were collected immediately after and 10 and 30 minutes after the 14CO2 fixation, divided into mesophyll, vein and stem bark, frozen in liquid N2 , and the contents of sucrose, glucose and fructose and their radioactivity were measured. The ratio of the radioactivity incorporated into sucrose to the total radioactivity incorporated into each tissue was very large, and the incorporation into glucose or fructose was very little. The content of sucrose was also larger than that of the other sugars in all the tissues. These findings showed that the photosynthates were translocated mainly in the form of sucrose. The ratio of specific radioactivity (dpm/mg sugar) in the mesophyll to that in the vein was 0.28, 0.58 and 0.42, respectively, immediately after, 10 minutes after and 30 minutes after the 14CO2 fixation for sucrose, 0.16, 0.39 and 0.29, respectively, for glucose, and 0.17, 0.25 and 0.46, respectively, for fructose. The specific radioactivity of sucrose in the vein 10 minutes after the fixation was as high as 58 % of that in the mesophyll, suggesting that the sucrose produced in the mesophyll was rapidly transported into the vein. (Kaihara, S.)

  20. 21 CFR 172.869 - Sucrose oligoesters.

    Science.gov (United States)

    2010-04-01

    ... the Food Chemicals Codex, 4th ed. (1996), p. 820. National Academy Press, 2101 Constitution Ave. NW... Ignition, Appendix IIC, Method I, in the Food Chemicals Codex, 4th ed. (1996), pp. 751-752, (using a 1-gram... for “Sucrose Fatty Acid Esters” in the First Supplement to the 4th ed. of the Food Chemicals...

  1. Effects of sucrose and sorbitol on cement-based stabilization/solidification of toxic metal waste.

    Science.gov (United States)

    Zhang, Linghong; Catalan, Lionel J J; Larsen, Andrew C; Kinrade, Stephen D

    2008-03-01

    The effects of sucrose or sorbitol addition on the hydration, unconfined compressive strength and leachability of Portland cement pastes containing 1% Pb and 1% Zn were studied as a function of time. Whereas Pb and Zn were found to shorten the time to achieve maximum hydration of Portland cement, the combination of these metals with 0.15 wt% sucrose or 0.40 wt% sorbitol retarded the setting of cement by at least 7 and 28 days, respectively, without affecting the strength at 56 days. The leachability of Pb and Zn evaluated by the TCLP 1311 protocol at 56 and 71 days was slightly reduced or unchanged by the addition of sucrose or sorbitol. SEM-EDS and XRD analyses revealed that ettringite precipitation was favored whereas the formation of CSH gel, which accounts for most of the strength of hydrated cement, was delayed in cement pastes containing both metals and sucrose or sorbitol. These results indicate that controlled additions of sucrose or sorbitol can add flexibility to the handling of cement-treated metal waste, particularly when it needs to be transported by truck or pipeline between the treatment plant and the disposal site, without affecting its long-term performance. PMID:17629400

  2. Shoot-supplied ammonium targets the root auxin influx carrier AUX1 and inhibits lateral root emergence in Arabidopsis

    KAUST Repository

    Li, Baohai

    2011-03-24

    Deposition of ammonium (NH4 +) from the atmosphere is a substantial environmental problem. While toxicity resulting from root exposure to NH4 + is well studied, little is known about how shoot-supplied ammonium (SSA) affects root growth. In this study, we show that SSA significantly affects lateral root (LR) development. We show that SSA inhibits lateral root primordium (LRP) emergence, but not LRP initiation, resulting in significantly impaired LR number. We show that the inhibition is independent of abscisic acid (ABA) signalling and sucrose uptake in shoots but relates to the auxin response in roots. Expression analyses of an auxin-responsive reporter, DR5:GUS, and direct assays of auxin transport demonstrated that SSA inhibits root acropetal (rootward) auxin transport while not affecting basipetal (shootward) transport or auxin sensitivity of root cells. Mutant analyses indicated that the auxin influx carrier AUX1, but not the auxin efflux carriers PIN-FORMED (PIN)1 or PIN2, is required for this inhibition of LRP emergence and the observed auxin response. We found that AUX1 expression was modulated by SSA in vascular tissues rather than LR cap cells in roots. Taken together, our results suggest that SSA inhibits LRP emergence in Arabidopsis by interfering with AUX1-dependent auxin transport from shoot to root. © 2011 Blackwell Publishing Ltd.

  3. Metabolism of sucrose during storage in intact sorghum stalk

    International Nuclear Information System (INIS)

    Grasses of the Andropogoneae, such as sorghum (Sorghum bicolor [L.] Moench) and sugarcane (Saccharum spp.), accumulate large amounts of harvestable sucrose in the stalk. Sucrose is translocated from the leaves, yet the metabolic fate of sucrose up to and during storage in the stalk is uncertain. This study determined whether sucrose is necessarily routed through inversion and hexose-phosphate isomerization for storage in cells of the intact stalk. Sorghum stalks were dual-infused with [U-14C]sucrose and [fructose-1-3H(N)]sucrose during stages of sucrose accumulation. Unperturbed tissue was used for subsequent sugar analyses. Solutes in cell extracts were separated sequentially through enzymatic conversion and ion-exchange removal of the reaction products. The hexose moieties of sucrose were analyzed separately. A mean of 95% of recovered 14C was in sucrose. In sucrose, 46% of 14C and 77% of 3H were recovered in the fructose moiety. The significant retention of asymmetry in tritium labeling of sucrose indicates that a cycle of cleavage and resynthesis did not dominate sucrose accumulation in cells of the sorghum stalk. (author)

  4. Identification of drought-response genes and a study of their expression during sucrose accumulation and water deficit in sugarcane culms

    Directory of Open Access Journals (Sweden)

    Xu Jingsheng

    2011-01-01

    Full Text Available Abstract Background The ability of sugarcane to accumulate high concentrations of sucrose in its culm requires adaptation to maintain cellular function under the high solute load. We have investigated the expression of 51 genes implicated in abiotic stress to determine their expression in the context of sucrose accumulation by studying mature and immature culm internodes of a high sucrose accumulating sugarcane cultivar. Using a sub-set of eight genes, expression was examined in mature internode tissues of sugarcane cultivars as well as ancestral and more widely related species with a range of sucrose contents. Expression of these genes was also analysed in internode tissue from a high sucrose cultivar undergoing water deficit stress to compare effects of sucrose accumulation and water deficit. Results A sub-set of stress-related genes that are potentially associated with sucrose accumulation in sugarcane culms was identified through correlation analysis, and these included genes encoding enzymes involved in amino acid metabolism, a sugar transporter and a transcription factor. Subsequent analysis of the expression of these stress-response genes in sugarcane plants that were under water deficit stress revealed a different transcriptional profile to that which correlated with sucrose accumulation. For example, genes with homology to late embryogenesis abundant-related proteins and dehydrin were strongly induced under water deficit but this did not correlate with sucrose content. The expression of genes encoding proline biosynthesis was associated with both sucrose accumulation and water deficit, but amino acid analysis indicated that proline was negatively correlated with sucrose concentration, and whilst total amino acid concentrations increased about seven-fold under water deficit, the relatively low concentration of proline suggested that it had no osmoprotectant role in sugarcane culms. Conclusions The results show that while there was a

  5. Arabidopsis phosphatidylinositol monophosphate 5-kinase 2 is involved in root gravitropism through regulation of polar auxin transport by affecting the cycling of PIN proteins

    OpenAIRE

    Mei, Yu; Jia, Wen-Jing; Chu, Yu-Jia; Xue, Hong-Wei

    2011-01-01

    Phosphatidylinositol monophosphate 5-kinase (PIP5K) catalyzes the synthesis of PI-4,5-bisphosphate (PtdIns(4,5)P2) by phosphorylation of PI-4-phosphate at the 5 position of the inositol ring, and is involved in regulating multiple developmental processes and stress responses. We here report on the functional characterization of Arabidopsis PIP5K2, which is expressed during lateral root initiation and elongation, and whose expression is enhanced by exogenous auxin. The knockout mutant pip5k...

  6. Sucrose Inversion An Experiment on Heterogeneous Catalysis

    OpenAIRE

    Adélio Mendes; Magalhães, Fernão D.; Luis M. Madeira

    2003-01-01

    llustration of heterogeneous catalysis concepts in laboratory courses is not usually simple or economical. For our undergraduate senior lab course we have developed an environmentally friendly experiment dealing with several aspects of heterogeneous catalysis, having in mind the use of readily available and relatively inexpensive equipment, and chemicals on a compact setup, which students can safely operate. The experiment deals with the acid-catalyzed sucrose inversion, performed in packed b...

  7. Review: Post-translational cross-talk between brassinosteroid and sucrose signaling.

    Science.gov (United States)

    Kühn, Christina

    2016-07-01

    A direct link has been elucidated between brassinosteroid function and perception, and sucrose partitioning and transport. Sucrose regulation and brassinosteroid signaling cross-talk at various levels, including the well-described regulation of transcriptional gene expression: BZR-like transcription factors link the signaling pathways. Since brassinosteroid responses depend on light quality and quantity, a light-dependent alternative pathway was postulated. Here, the focus is on post-translational events. Recent identification of sucrose transporter-interacting partners raises the question whether brassinosteroid and sugars jointly affect plant innate immunity and plant symbiotic interactions. Membrane permeability and sensitivity depends on the number of cell surface receptors and transporters. More than one endocytic route has been assigned to specific components, including brassinosteroid-receptors. The number of such proteins at the plasma membrane relies on endocytic recycling, internalization and/or degradation. Therefore, vesicular membrane trafficking is gaining considerable attention with regard to plant immunity. The organization of pattern recognition receptors (PRRs), other receptors or transporters in membrane microdomains participate in endocytosis and the formation of specific intracellular compartments, potentially impacting biotic interactions. This minireview focuses on post-translational events affecting the subcellular compartmentation of membrane proteins involved in signaling, transport, and defense, and on the cross-talk between brassinosteroid signals and sugar availability. PMID:27181949

  8. Crystallization inhibition of an amorphous sucrose system using raffinose

    Institute of Scientific and Technical Information of China (English)

    LEINEN K.M.; LABUZA T.P.

    2006-01-01

    The shelf life of pure amorphous sucrose systems, such as cotton candy, can be very short. Previous studies have shown that amorphous sucrose systems held above the glass transition temperature will collapse and crystallize. One study,however, showed that adding a small percent of another type of sugar, such as trehalose, to sucrose can extend the shelf life of the amorphous system by slowing crystallization. This study explores the hypothesis that raffinose increases the stability of an amorphous sucrose system. Cotton candy at 5 wt% raffinose and 95 wt% sucrose was made and stored at room temperature and three different relative humidities (%RH) 11%RH, 33%RH, and 43%RH. XRD patterns, and glass transition temperatures were obtained to determine the stability as a function of %RH. The data collected showed that raffinose slows sucrose crystallization in a low moisture amorphous state above the glass transition temperature and therefore improves the stability of amorphous sucrose systems.

  9. STUDY ON THE SYNTHESIS AND PHYSICOCHEMICAL PROPERTIES OF SUCROSE POLYESTER

    Institute of Scientific and Technical Information of China (English)

    LIU Zhongdong; LIU Huihua; LUO Peng; LIU Peng; Xiao Fugang

    2006-01-01

    Orthogonal test was used to evaluate the effects of synthetic such as temperature (120~140 ℃), reaction time (4-6) and substrate molar ratio of methyl oleate to sucrose (8:1-12:1) on the percent quantity conversion to sucrose polyester. Sucrose polyester was synthesized by a solvent-free one-stage interesterification. The optimum reaction conditions are as follows: methyl oleate/sucrose = 10∶1 (mol/mol); reaction temperature is 140 ℃;yield reaches 88.15%, and the degree of esterification (DE) is over 7 in the conditions. Thin layer chromatography (TLC), column chromatography (CC), High-performance liquid chromatography (HPLC) were used to analyze the product, the results show that the percent of sucrose polyoleate is over 70% in the product. The physicochemical properties of sucrose polyesters were compared with cooking oil. The results show that the qualities of sucrose polyesters are all up to the triglyceride.

  10. Changes in the Phosphoproteome and Metabolome Link Early Signaling Events to Rearrangement of Photosynthesis and Central Metabolism in Salinity and Oxidative Stress Response in Arabidopsis.

    Science.gov (United States)

    Chen, Yanmei; Hoehenwarter, Wolfgang

    2015-12-01

    Salinity and oxidative stress are major factors affecting and limiting the productivity of agricultural crops. The molecular and biochemical processes governing the plant response to abiotic stress have often been researched in a reductionist manner. Here, we report a systemic approach combining metabolic labeling and phosphoproteomics to capture early signaling events with quantitative metabolome analysis and enzyme activity assays to determine the effects of salt and oxidative stress on plant physiology. K(+) and Na(+) transporters showed coordinated changes in their phosphorylation pattern, indicating the importance of dynamic ion homeostasis for adaptation to salt stress. Unique phosphorylation sites were found for Arabidopsis (Arabidopsis thaliana) SNF1 kinase homolog10 and 11, indicating their central roles in the stress-regulated responses. Seven Sucrose Non-fermenting1-Related Protein Kinase2 kinases showed varying levels of phosphorylation at multiple serine/threonine residues in their kinase domain upon stress, showing temporally distinct modulation of the various isoforms. Salinity and oxidative stress also lead to changes in protein phosphorylation of proteins central to photosynthesis, in particular the kinase State Transition Protein7 required for state transition and light-harvesting II complex proteins. Furthermore, stress-induced changes of the phosphorylation of enzymes of central metabolism were observed. The phosphorylation patterns of these proteins were concurrent with changes in enzyme activity. This was reflected by altered levels of metabolites, such as the sugars sucrose and fructose, glycolysis intermediates, and amino acids. Together, our study provides evidence for a link between early signaling in the salt and oxidative stress response that regulates the state transition of photosynthesis and the rearrangement of primary metabolism. PMID:26471895

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

    Science.gov (United States)

    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

  12. Membrane perturbing properties of sucrose polyesters.

    Science.gov (United States)

    McManus, G G; Buchanan, G W; Jarrell, H C; Epand, R M; Epand, R F; Cheetham, J J

    2001-02-01

    Sucrose polyester (SPE), in the form of sucrose octaesters and sucrose hexaesters of palmitic (16:0), stearic (18:0), oleic (18:1cis), and linoleic (18:2cis) acids, have many uses. Applications include: a non-caloric fat substitute, detoxification agent, and oral contrast agent for human abdominal (MRI) magnetic resonance imaging. However, it has been shown that the ingestion of SPE was shown to generate a depletion of physiologically important lipidic vitamins and other lipophilic molecules. In order to better understand, at the molecular level, the type of interaction between SPE and lipid membrane, we have, first synthesized different type of labelled and non-labelled SPEs. Secondly, we have studied the effect of SPEs on multilamellar dispersions of dielaidoylphosphatidylethanolamine (DEPE) and dipalmitoylphosphocholine (DPPC) as a function of temperature, SPE composition and concentration. The effects of SPEs were studied by differential scanning calorimetry (DSC), X-ray diffraction, 2H and 31P NMR spectroscopy. At low concentration (DPPC induce the formation of a non-bilayer phase as seen by 31P NMR. Order parameter measurements of DPPC-d62/SPE mixtures show that the SPE effect on the DPPC monolayer thickness is dependent on the SPE, concentration, chains length and saturation level. At higher concentration (> or = 10 mol%) SPE are very potent DEPE bilayer to HII phase transition promoters, although at that concentration the SPE have lost the ability to form cubic phases. SPEs have profound effects on the phase behaviour of model membrane systems, and may be important to consider when developing current and potential industrial and medical applications. PMID:11269937

  13. Comparison of freezing tolerance, compatible solutes and polyamines in geographically diverse collections of Thellungiella sp. and Arabidopsis thaliana accessions

    Directory of Open Access Journals (Sweden)

    Lee Yang

    2012-08-01

    Full Text Available Abstract Background Thellungiella has been proposed as an extremophile alternative to Arabidopsis to investigate environmental stress tolerance. However, Arabidopsis accessions show large natural variation in their freezing tolerance and here the tolerance ranges of collections of accessions in the two species were compared. Results Leaf freezing tolerance of 16 Thellungiella accessions was assessed with an electrolyte leakage assay before and after 14 days of cold acclimation at 4°C. Soluble sugars (glucose, fructose, sucrose, raffinose and free polyamines (putrescine, spermidine, spermine were quantified by HPLC, proline photometrically. The ranges in nonacclimated freezing tolerance completely overlapped between Arabidopsis and Thellungiella. After cold acclimation, some Thellungiella accessions were more freezing tolerant than any Arabidopsis accessions. Acclimated freezing tolerance was correlated with sucrose levels in both species, but raffinose accumulation was lower in Thellungiella and only correlated with freezing tolerance in Arabidopsis. The reverse was true for leaf proline contents. Polyamine levels were generally similar between the species. Only spermine content was higher in nonacclimated Thellungiella plants, but decreased during acclimation and was negatively correlated with freezing tolerance. Conclusion Thellungiella is not an extremophile with regard to freezing tolerance, but some accessions significantly expand the range present in Arabidopsis. The metabolite data indicate different metabolic adaptation strategies between the species.

  14. Role of sucrose phosphate synthase in sucrose biosynthesis in ripening bananas and its relationship to the respiratory climacteric.

    Science.gov (United States)

    Hubbard, N L; Pharr, D M; Huber, S C

    1990-09-01

    During ripening of bananas (Musa spp. [AAA group, Cavendish subgroup]), there is a massive conversion of starch to sucrose. Also during ripening there is a rise in respiration known as the respiratory climacteric. In this study changes in carbohydrate content, activities of starch and sucrose metabolizing enzymes, and respiration were measured to assess their potential interrelationships. Sucrose phosphate synthase activity increased dramatically during the first 4 days after initiation of ripening by ethylene treatment. Starch concentration decreased and sucrose concentration increased during this time period. Developmental changes in sucrose phosphate synthase activity were measured with limiting substrate (plus Pi) and saturating substrate concentrations. Activities were not parallel under the two assay conditions, providing tentative evidence that kinetically different forms of the enzyme may exist at different stages of ripening. Sucrose accumulation rate was most highly correlated with sucrose phosphate synthase activity assayed with limiting substrate concentrations (plus Pi). The cumulative amount of CO(2) respired during ripening was positively correlated with sugar accumulation (R(2) = 0.97). From this linear regression it was calculated that a constant 0.605 millimoles of CO(2) was evolved per mole of sucrose formed throughout ripening. Using this quantity, the percentage of the total respiratory ATP produced which was required for the conversion of starch to sucrose was calculated assuming different models for carbon export from the amyloplast. The results suggest that sucrose biosynthesis during ripening constitutes a significant sink for respiratory ATP. PMID:16667688

  15. Comprehensive Mutational Analysis of Sucrose-Metabolizing Pathways in Streptococcus mutans Reveals Novel Roles for the Sucrose Phosphotransferase System Permease

    Science.gov (United States)

    Zeng, Lin

    2013-01-01

    Sucrose is perhaps the most efficient carbohydrate for the promotion of dental caries in humans, and the primary caries pathogen Streptococcus mutans encodes multiple enzymes involved in the metabolism of this disaccharide. Here, we engineered a series of mutants lacking individual or combinations of sucrolytic pathways to understand the control of sucrose catabolism and to determine whether as-yet-undisclosed pathways for sucrose utilization were present in S. mutans. Growth phenotypes indicated that gtfBCD (encoding glucan exopolysaccharide synthases), ftf (encoding the fructan exopolysaccharide synthase), and the scrAB pathway (sugar-phosphotransferase system [PTS] permease and sucrose-6-PO4 hydrolase) constitute the majority of the sucrose-catabolizing activity; however, mutations in any one of these genes alone did not affect planktonic growth on sucrose. The multiple-sugar metabolism pathway (msm) contributed minimally to growth on sucrose. Notably, a mutant lacking gtfBC, which cannot produce water-insoluble glucan, displayed improved planktonic growth on sucrose. Meanwhile, loss of scrA led to growth stimulation on fructooligosaccharides, due in large part to increased expression of the fruAB (fructanase) operon. Using the LevQRST four-component signal transduction system as a model for carbohydrate-dependent gene expression in strains lacking extracellular sucrases, a PlevD-cat (EIIALev) reporter was activated by pulsing with sucrose. Interestingly, ScrA was required for activation of levD expression by sucrose through components of the LevQRST complex, but not for activation by the cognate LevQRST sugars fructose or mannose. Sucrose-dependent catabolite repression was also evident in strains containing an intact sucrose PTS. Collectively, these results reveal a novel regulatory circuitry for the control of sucrose catabolism, with a central role for ScrA. PMID:23222725

  16. Leaves Of Cut Rose Flower Convert Exogenously Applied Glucose To Sucrose And Translocate It To Petals

    Directory of Open Access Journals (Sweden)

    Horibe Takanori

    2014-12-01

    Full Text Available To understand the role that the leaves play in the translocation of soluble carbohydrates in cut rose flowers, we first evaluated the effect of leaf removal on flower quality and the sugar content in petals. Cut rose flowers with leaves had higher soluble sugar content in petals compared with cut flower without leaves. Next, we treated cut flowers with radioactive glucose to clarify translocation routes of exogenously applied sugar. There was no significant difference between the specific radioactivity of sucrose and glucose in leaves, but specific radioactivity of sucrose in petals was much higher than that of glucose. These results suggested that most of the exogenously applied glucose first moved to the leaves, where it was converted into sucrose and then the synthesised sucrose was translocated to the petals. Our results showed that the leaves of cut rose flowers play an important role in the metabolism and transportation of exogenously applied soluble carbohydrates toward the petals, thus contributing to sustaining the post-harvest quality.

  17. New insights into carbon transport and incorporation to wood

    OpenAIRE

    Mahboubi, Amir

    2015-01-01

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species the majority of this carbon is derived from sucrose transported in the phloem. This thesis describes experimental work on the mechanism of radial sucrose transport from phloem to developing wood and subsequent incorporation of carbon into wood polymers. I investigated the role of active sucrose transport during secondary cell wall formation in hybrid aspen (Populus tremula x tremuloides...

  18. Tissue- and isoform-specific phytochrome regulation of light-dependent anthocyanin accumulation in Arabidopsis thaliana

    OpenAIRE

    Warnasooriya, Sankalpi N.; Porter, Katie J.; Montgomery, Beronda L

    2011-01-01

    Phytochromes regulate light- and sucrose-dependent anthocyanin synthesis and accumulation in many plants. Mesophyll-specific phyA alone has been linked to the regulation of anthocyanin accumulation in response to far-red light in Arabidopsis thaliana. However, multiple mesophyll-localized phytochromes were implicated in the photoregulation of anthocyanin accumulation in red-light conditions. Here, we report a role for mesophyll-specific phyA in blue-light-dependent regulation of anthocyanin l...

  19. Fructose signalling unbalancing and effect on Arabidopsis growth and the photosynthetic pigments content

    OpenAIRE

    Barnes Ontiveros, Rafael; Fiñaga Cortés, Marina; López Rodrigo, Francisco; Noguera Vilches, María Elena; Rodríguez Ibáñez, Claudia; Sahrawy, Mariam; Serrato, Antonio Jesús

    2013-01-01

    Sugar biosynthesis, tightly regulated in plants, depends on photosynthesis as the only biochemical process able to fix atmospheric CO2 in photoautotrophic organisms. In Arabidopsis thaliana, sucrose, glucose, and fructose are the most abundant soluble sugars. Sugar pools are fluctuating during the day/night cycle responding to plant requirements, as the growth stage or the response to diverse environmental stresses. For that reason, plants have developed signalling mechanisms t...

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

    Science.gov (United States)

    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

  1. Control of Enzyme IIscr and Sucrose-6-Phosphate Hydrolase Activities in Streptococcus mutans by Transcriptional Repressor ScrR Binding to the cis-Active Determinants of the scr Regulon

    OpenAIRE

    Wang, Bing; Kuramitsu, Howard K.

    2003-01-01

    In Streptococcus mutans, enzyme IIscr and sucrose-6-phosphate hydrolase are two important enzymes in the transport and metabolism of dietary sucrose. The scr regulon of S. mutans is composed of three genes, scrA and scrB, which code for enzyme IIscr and sucrose-6-phosphate hydrolase, respectively, and scrR, which codes for a GalR-LacI-type transcription regulator. It was previously shown that expression of both scrA and scrB is similarly induced by sucrose. Mutation in the scrR gene resulted ...

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

    Directory of Open Access Journals (Sweden)

    Vietor Donald M

    2007-06-01

    Full Text Available Abstract 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

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

    Science.gov (United States)

    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

  4. Graded sucrose/carbohydrate diets in overtly hypertriglyceridemic diabetic patients.

    Science.gov (United States)

    Jellish, W S; Emanuele, M A; Abraira, C

    1984-12-01

    Overtly hypertriglyceridemic patients with non-insulin-dependent diabetes mellitus were given a control diet containing 120 g of sucrose and 50 percent carbohydrate, and later randomly assigned to receive isocaloric high- (220 g), intermediate- (120 g), or low- (less than 3 g) sucrose/carbohydrate diets for four weeks. The low-sucrose diet group demonstrated a modest but significant decrease in mean fasting serum glucose level in the first week only, although this change was no different from the other two dietary groups and was not sustained. All groups had little change in late postprandial serum glucose levels from control values, and no significant alterations in 24-hour glycosuria. The high-sucrose diet group demonstrated a significant increase in fasting serum triglyceride levels by the second week of the study, whereas the intermediate- and low-sucrose diet groups showed a decrease in mean fasting triglyceride levels. In contrast, the low-sucrose diet group's late postprandial serum triglyceride levels increased by the fourth week, whereas levels fell in the high-sucrose diet group. Mean fasting serum cholesterol concentrations decreased from control values in the high-sucrose diet group. Thus, although very high sucrose and carbohydrate consumption is clearly deleterious to fasting tryglyceride levels in non-insulin-dependent diabetes mellitus with preexisting hypertriglyceridemia, it appears that low dietary sucrose and carbohydrate proportions do not further improve preprandial glycemia and glycosuria and may adversely affect late postprandial serum triglyceride concentration. This study suggests that isocaloric sucrose and carbohydrate restriction below usual daily levels (120 g per day) offers no consistent benefit in glycemia or lipid control in overt type II diabetes. PMID:6391162

  5. Regulation of sucrose metabolism in higher plants: localization and regulation of activity of key enzymes

    Science.gov (United States)

    Winter, H.; Huber, S. C.; Brown, C. S. (Principal Investigator)

    2000-01-01

    Sucrose (Suc) plays a central role in plant growth and development. It is a major end product of photosynthesis and functions as a primary transport sugar and in some cases as a direct or indirect regulator of gene expression. Research during the last 2 decades has identified the pathways involved and which enzymes contribute to the control of flux. Availability of metabolites for Suc synthesis and 'demand' for products of sucrose degradation are important factors, but this review specifically focuses on the biosynthetic enzyme sucrose-phosphate synthase (SPS), and the degradative enzymes, sucrose synthase (SuSy), and the invertases. Recent progress has included the cloning of genes encoding these enzymes and the elucidation of posttranslational regulatory mechanisms. Protein phosphorylation is emerging as an important mechanism controlling SPS activity in response to various environmental and endogenous signals. In terms of Suc degradation, invertase-catalyzed hydrolysis generally has been associated with cell expansion, whereas SuSy-catalyzed metabolism has been linked with biosynthetic processes (e.g., cell wall or storage products). Recent results indicate that SuSy may be localized in multiple cellular compartments: (1) as a soluble enzyme in the cytosol (as traditionally assumed); (2) associated with the plasma membrane; and (3) associated with the actin cytoskeleton. Phosphorylation of SuSy has been shown to occur and may be one of the factors controlling localization of the enzyme. The purpose of this review is to summarize some of the recent developments relating to regulation of activity and localization of key enzymes involved in sucrose metabolism in plants.

  6. Arabidopsis CDS blastp result: AK241580 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241580 J065181H03 At4g23640.1 68417.m03404 potassium transporter / tiny root hair ... 1 protein (T ... RH1) identical to tiny root hair ... 1 protein [Arabidopsis thaliana] gi|11181958|emb|C ... MID:11500563; identical to cDNA mRNA for tiny root hair ... 1 protein (trh1) GI:11181957 1e-139 ...

  7. Citrate increases glass transition temperature of vitrified sucrose preparations

    NARCIS (Netherlands)

    Kets, E.P.W.; Lipelaar, P.J.; Hoekstra, F.A.; Vromans, H.

    2004-01-01

    The aim of this study was to investigate the effect of sodium citrate on the properties of dried amorphous sucrose glasses. Addition of sodium citrate to a sucrose solution followed by freeze-drying or convective drying resulted in a glass transition temperature (T-g) that was higher than the well-s

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

    Science.gov (United States)

    Marques, Wesley Leoricy; Raghavendran, Vijayendran; Stambuk, Boris Ugarte; Gombert, Andreas Karoly

    2016-02-01

    Sucrose is an abundant, readily available and inexpensive substrate for industrial biotechnology processes and its use is demonstrated with much success in the production of fuel ethanol in Brazil. Saccharomyces cerevisiae, which naturally evolved to efficiently consume sugars such as sucrose, is one of the most important cell factories due to its robustness, stress tolerance, genetic accessibility, simple nutrient requirements and long history as an industrial workhorse. This minireview is focused on sucrose metabolism in S. cerevisiae, a rather unexplored subject in the scientific literature. An analysis of sucrose availability in nature and yeast sugar metabolism was performed, in order to understand the molecular background that makes S. cerevisiae consume this sugar efficiently. A historical overview on the use of sucrose and S. cerevisiae by humans is also presented considering sugarcane and sugarbeet as the main sources of this carbohydrate. Physiological aspects of sucrose consumption are compared with those concerning other economically relevant sugars. Also, metabolic engineering efforts to alter sucrose catabolism are presented in a chronological manner. In spite of its extensive use in yeast-based industries, a lot of basic and applied research on sucrose metabolism is imperative, mainly in fields such as genetics, physiology and metabolic engineering. PMID:26658003

  9. Analysis and protease-catalysed synthesis of sucrose alkanoate regioisomers

    DEFF Research Database (Denmark)

    Lie, Aleksander

    2014-01-01

    detected appearance of the sucrose laurate regioisomers largely corresponded to the apparent rates of formation, based on monoester concentration and regioisomeric distribution after 48 hours, and 2-O-lauroyl sucrose was among the first regioisomers to appear in all investigated reactions. The...

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

    Science.gov (United States)

    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...

  11. The F-box protein MAX2 contributes to resistance to bacterial phytopathogens in Arabidopsis thaliana

    OpenAIRE

    PiisilÀ, Maria; Keceli, Mehmet A; Brader, GÌnter; Jakobson, Liina; Jõesaar, Indrek; Sipari, Nina; Kollist, Hannes; Palva, E. T.; Kariola, Tarja

    2015-01-01

    Abstract Background The Arabidopsis thaliana F-box protein MORE AXILLARY GROWTH2 (MAX2) has previously been characterized for its role in plant development. MAX2 appears essential for the perception of the newly characterized phytohormone strigolactone, a negative regulator of polar auxin transport in Arabidopsis. Results A reverse genetic screen for F-box protein ...

  12. Gene Expression of the NO3– Transporter NRT1.1 and the Nitrate Reductase NIA1 Is Repressed in Arabidopsis Roots by NO2–, the Product of NO3– Reduction

    Science.gov (United States)

    Loqué, Dominique; Tillard, Pascal; Gojon, Alain; Lepetit, Marc

    2003-01-01

    NRT1.1 and NIA1 genes, which encode a nitrate (NO3–) transporter and the minor isoform of NO3– reductase (NR), respectively, are overexpressed in roots of NR-deficient mutants of Arabidopsis grown on nutrient solution containing NO3– and reduced N. The overexpression is found only in mutants with reduced NIA2 activity, and disruption of the NIA1 gene alone has no effect on NRT1.1 expression. Because the up-regulation of NRT1.1 and NIA1 is observed in N-sufficient NR mutant plants, it cannot be related to a release of the general feedback repression exerted by the N status of the plant. Our data do not support the hypothesis of overinduction of these genes by an increased concentration of NO3– in tissues. Furthermore, although a control by external pH might contribute to the regulation of NRT1.1, changes in external pH due to lack of NR activity cannot alone explain the up-regulation of both genes. The stimulation of NRT1.1 and NIA1 in NR mutants in these conditions suggests that NR activity is able to repress directly the expression of both genes independently of the availability of reduced N metabolites in wild-type plants. Accordingly, nitrite (NO2–) strongly represses NRT1.1 and NIA1 transcript accumulation in the roots. This effect is rapid, specific, and reversible. Furthermore, transport studies on plants exposed to NO2– show that down-regulation of the NRT1.1 gene is associated with a decrease in NO3– influx. These results indicate that feedback regulation of genes of NO3– assimilation relies not only on the repression exerted by reduced N metabolites, such as NH4+ or amino acids, but may also involve the action of NO2– as a regulatory signal. PMID:12805624

  13. Sucrose utilization by Zymomonas mobilis: formation of a levan

    Science.gov (United States)

    Dawes, E. A.; Ribbons, D. W.; Rees, D. A.

    1966-01-01

    1. Molar growth-yield coefficients of Zymomonas mobilis for glucose, fructose, glucose plus fructose, and sucrose are reported. Yield coefficients for sucrose are appreciably lower than those for the equivalent concentrations of glucose plus fructose. 2. Only 2·6% of [U-14C]glucose supplied in the growth medium is incorporated into cell substance by Z. mobilis utilizing glucose as the energy source. 3. During growth on sucrose a levan is formed. It has been characterized and shown to resemble other bacterial levans. 4. Levan formation from sucrose could be demonstrated with both washed cell suspensions and cell extracts of Z. mobilis. 5. Sucrose phosphorylase could not be demonstrated in extracts of the organism. PMID:4287843

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

    Science.gov (United States)

    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. PMID:26304437

  15. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael;

    1992-01-01

    Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression. ...

  16. Enhancement of cellulose production by expression of sucrose synthase in Acetobacter xylinum

    OpenAIRE

    Nakai, Tomonori; Tonouchi, Naoto; Konishi, Teruko; Kojima, Yukiko; Tsuchida, Takayasu; Yoshinaga, Fumihiro; Sakai, Fukumi; Hayashi, Takahisa

    1999-01-01

    Higher plants efficiently conserve energy ATP in cellulose biosynthesis by expression of sucrose synthase, in which the high free energy between glucose and fructose in sucrose can be conserved and used for the synthesis of UDP-glucose. A mixture of sucrose synthase and bacterial cellulose synthase proceeded to form UDP-glucose from sucrose plus UDP and to synthesize 1,4-β-glucan from the sugar nucleotide. The mutant sucrose synthase, which mimics phosphorylated sucrose synthase, enhanced the...

  17. Protocol: optimised electrophyiological analysis of intact guard cells from Arabidopsis

    Directory of Open Access Journals (Sweden)

    Chen Zhong-Hua

    2012-05-01

    Full Text Available Abstract Genetic resources available for Arabidopsis thaliana make this species particularly attractive as a model for molecular genetic studies of guard cell homeostasis, transport and signalling, but this facility is not matched by accessible tools for quantitative analysis of transport in the intact cell. We have developed a reliable set of procedures for voltage clamp analysis of guard cells from Arabidopsis leaves. These procedures greatly simplify electrophysiological recordings, extending the duration of measurements and scope for analysis of the predominant K+ and anion channels of intact stomatal guard cells to that achieved previously in work with Vicia and tobacco guard cells.

  18. Sucrose and IQ induced mutations in rat colon by independent

    DEFF Research Database (Denmark)

    Hansen, Max; Hald, M. T.; Autrup, H.;

    2004-01-01

    Sucrose-rich diets have repeatedly been observed to have co-carcinogenic actions in colon and liver of rats and to increase the number of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) induced aberrant crypt foci in rat colon. To investigate a possible interaction between sucrose and IQ on the...... genotoxicity in rat liver and colon, we gave Big Blue rats(TM) a diet containing sucrose (0%, 3.45% or 13.4% w/w) and/or IQ (70 ppm) for a period of 3 weeks. Sucrose and IQ increased the mutation frequency in the colon. The effect of combined treatments with IQ and sucrose on the mutation frequencies was...... additive indicating that sucrose and IQ act independently. This was supported by the mutation spectra where sucrose expands the background mutations in the colon, whereas IQ, in other studies, more specifically has induced G:C --> T:A transversions. In the liver IQ increased the mutation frequency, whereas...

  19. Characterization of Sucrose Thin Films for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    S. L. Iconaru

    2011-01-01

    Full Text Available Sucrose is a natural osmolyte accumulated in the cells of organisms as they adapt to environmental stress. In vitro sucrose increases protein stability and forces partially unfolded structures to refold. Thin films of sucrose (C12H22O11 were deposited on thin cut glass substrates by the thermal evaporation technique (P∼10−5 torr. Characteristics of thin films were put into evidence by Fourier Transform Infrared Spectroscopy (FTIR, X-ray Photoelectron Spectroscopy (XPS, scanning electron microscopy (SEM, and differential thermal analysis and thermal gravimetric analysis (TG/DTA. The experimental results confirm a uniform deposition of an adherent layer. In this paper we present a part of the characteristics of sucrose thin films deposited on glass in medium vacuum conditions, as a part of a culture medium for osteoblast cells. Osteoblast cells were used to determine proliferation, viability, and cytotoxicity interactions with sucrose powder and sucrose thin films. The osteoblast cells have been provided from the American Type Culture Collection (ATCC Centre. The outcome of this study demonstrated the effectiveness of sucrose thin films as a possible nontoxic agent for biomedical applications.

  20. Functional Relationship between Sucrose and a Cariogenic Biofilm Formation

    Science.gov (United States)

    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

  1. Transport

    International Nuclear Information System (INIS)

    Transport is one of the major causes of environmental damage in Austria. Energy consumption, pollutants emissions, noise emissions, use of surfaces, sealing of surfaces, dissection of ecosystems and impact on landscape are the most significant environmental impacts caused by it. An overview of the transport development of passengers and freight in Austria is presented. Especially the energy consumption growth, carbon dioxide and nitrogen oxide emissions by type of transport, and the emissions development (HC, particle and carbon monoxide) of goods and passengers transport are analyzed covering the years 1980 - 1999. The health cost resulting from transport-related air pollution in Austria is given and measures to be taken for an effective control of the transport sector are mentioned. Figs. 8, Table 1. (nevyjel)

  2. STP10 encodes a high-affinity monosaccharide transporter and is induced under low-glucose conditions in pollen tubes of Arabidopsis.

    Science.gov (United States)

    Rottmann, Theresa; Zierer, Wolfgang; Subert, Christa; Sauer, Norbert; Stadler, Ruth

    2016-04-01

    Pollen tubes are fast growing, photosynthetically inactive cells. Their energy demand is covered by specific transport proteins in the plasma membrane that mediate the uptake of sugars. Here we report on the functional characterization of AtSTP10, a previously uncharacterized member of the SUGAR TRANSPORT PROTEIN family. Heterologous expression of STP10 cDNA in yeast revealed that the encoded protein catalyses the high-affinity uptake of glucose, galactose and mannose. The transporter is sensitive to uncouplers of transmembrane proton gradients, indicating that the protein acts as a hexose-H(+)symporter. Analyses of STP10 mRNA and STP10 promoter-reporter gene studies revealed a sink-specific expression pattern of STP10 in primordia of lateral roots and in pollen tubes. This restriction to sink organs is mediated by intragenic regions of STP10 qPCR analyses with cDNA of in vitro grown pollen tubes showed that STP10 expression was down-regulated in the presence of 50mM glucose. However, in pollen tubes of glucose-insensitive plants, which lack the glucose sensor hexokinase1 (HXK1), no glucose-induced down-regulation of STP10 expression was detected. A stp10T-DNA insertion line developed normally, which may point towards functional redundancy. The data presented in this paper indicate that a high-affinity glucose uptake system is induced in growing pollen tubes under low glucose conditions and that this regulation may occur through the hexokinase pathway. PMID:26893494

  3. Cytokinin-Regulated Sucrose Metabolism in Stay-Green Wheat Phenotype.

    Science.gov (United States)

    Wang, Wenqiang; Hao, Qunqun; Tian, Fengxia; Li, Qinxue; Wang, Wei

    2016-01-01

    A wheat stay-green mutant, tasg1, was observed to exhibit significantly delayed senescence in the late developmental stage. The photosynthetic capacity of the flag leaf was greater in tasg1 than in wild type (WT) plants. In addition, the grain volume of tasg1 was significantly higher than that of WT at the early filling stage. The content of various cytokinins (CKs) in the grain was significantly higher in tasg1 than in WT and was accompanied by an upregulated expression of some cell cycle-related genes. Examination of the metabolism of soluble sugars in tasg1 and WT revealed that the concentrations of glucose (Glu), fructose (Fru), and sucrose (Suc) were higher in the flag leaves and grains of tasg1 than in WT plants. The activities of sucrose-phosphate synthase (SPS), sucrose synthase (SuSy), and cell wall invertase (CW-invertase) were higher in tasg1, suggesting an altered metabolism and transport of soluble sugars. Furthermore, when tasg1 was treated with the CK inhibitor lovastatin, the activity of invertase was inhibited and was associated with premature senescence phenotype. However, the activity of invertase was partially recovered in tasg1 when treated with 6-benzylaminopurine (BAP). The trend of change in the concentrations of Glu, Fru, and Suc was similar to that of invertase. Our results suggest that CKs might regulate the stay-green phenotype of tasg1 by regulating the invertase activity involved in Suc remobilization. PMID:27580166

  4. Physicochemical characterization and cytotoxic studies of nonionic surfactant vesicles using sucrose esters as oral delivery systems.

    Science.gov (United States)

    Valdés, Karina; Morilla, María José; Romero, Eder; Chávez, Jorge

    2014-05-01

    Several nanotechnological solutions for mucosal immunization have been proposed, such as nanoparticles, liposomes, solid lipidic particles, micelles, and surfactant vesicles. In recent years, surfactant vesicles have gained increasing scientific attention as an alternative potential drug delivery system to the conventional liposome. This type of vesicle known as niosomes or nonionic surfactant vesicles (NSVs) has a structure and properties similar to those of liposomes. Both of them can transport hydrophilic drugs by encapsulation in the aqueous inner pool or hydrophobic drugs by intercalation into hydrophobic domains. The aim of this study was to prepare and characterize vesicles formed by sucrose esters as protective systems of bioactive molecules for oral administration. Vesicles were prepared using two commercial products formed by mixtures of mono and diesters S-570 and S-770, respectively. Determined parameters were size and zeta potential; the stability of formulations was tested in presence of increasing concentrations of a surfactant, and at several pH values observed in the gastrointestinal tract. Solubilization experiences showed an initial decrease in size for vesicles of both ester mixtures, samples showed detergent resistance at higher Triton X-100 concentrations. Vesicles showed stability at pH 5-7.4 up to 90 min; however, both formulations showed colloidal instability at pH=2, which corresponds to the isoelectric point of these vesicles. To evaluate the cytotoxicity of both vesicle formulations and separately each pure ester, Caco-2 cells were used. Cytotoxic evaluation indicated that both types of vesicles and free sucrose distearate were safe for Caco-2 viability; however, free sucrose monostearate was toxic for the cells. As a conclusion of these preliminary studies, it can be stated that vesicles formed with mixtures of sucrose esters showed a size in the range of 200 nm maintaining their size when exposed to the action of a surfactant, but

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

    Science.gov (United States)

    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. PMID:2659302

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

    Science.gov (United States)

    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

  7. Dynamics of Streptococcus mutans transcriptome in response to starch and sucrose during biofilm development.

    Directory of Open Access Journals (Sweden)

    Marlise I Klein

    Full Text Available The combination of sucrose and starch in the presence of surface-adsorbed salivary α-amylase and bacterial glucosyltransferases increase the formation of a structurally and metabolically distinctive biofilm by Streptococcus mutans. This host-pathogen-diet interaction may modulate the formation of pathogenic biofilms related to dental caries disease. We conducted a comprehensive study to further investigate the influence of the dietary carbohydrates on S. mutans-transcriptome at distinct stages of biofilm development using whole genomic profiling with a new computational tool (MDV for data mining. S. mutans UA159 biofilms were formed on amylase-active saliva coated hydroxyapatite discs in the presence of various concentrations of sucrose alone (ranging from 0.25 to 5% w/v or in combination with starch (0.5 to 1% w/v. Overall, the presence of sucrose and starch (suc+st influenced the dynamics of S. mutans transcriptome (vs. sucrose alone, which may be associated with gradual digestion of starch by surface-adsorbed amylase. At 21 h of biofilm formation, most of the differentially expressed genes were related to sugar metabolism, such as upregulation of genes involved in maltose/maltotriose uptake and glycogen synthesis. In addition, the groEL/groES chaperones were induced in the suc+st-biofilm, indicating that presence of starch hydrolysates may cause environmental stress. In contrast, at 30 h of biofilm development, multiple genes associated with sugar uptake/transport (e.g. maltose, two-component systems, fermentation/glycolysis and iron transport were differentially expressed in suc+st-biofilms (vs. sucrose-biofilms. Interestingly, lytT (bacteria autolysis was upregulated, which was correlated with presence of extracellular DNA in the matrix of suc+st-biofilms. Specific genes related to carbohydrate uptake and glycogen metabolism were detected in suc+st-biofilms in more than one time point, indicating an association between presence of starch

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

    Science.gov (United States)

    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

  9. Enzymatic Synthesis of Sucrose Polyester as Food Emulsifier Compound

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2012-12-01

    Full Text Available Sucrose polyester (SPE is a carbohydrate ester compound that has diverse functions, from surfactant to low-calorie food products. Sucrose fatty acid ester with the degree of substitution 1-3 can be used as emulsifier in foods and cosmetics. The enzymatic synthesis of sucrose polyesters can be carried out using lipase in organic solvent and contain small amount of water. In these studies sucrose esters were synthesized by esterification reaction between sucrose with fatty acids from coconut and palm oil using Candida rugosa lipase in n-hexane. Optimization esterification reaction carried out for parameters of incubation time, temperature, and the ratio of the substrate. The optimum incubation time is at 18 hours for coconut oil and 12 hours palm oil, the optimum temperature is 30 oC for coconut and palm oil, and the mole ratio of fatty acid to sucrose is 40:1 for coconut oil and 64:1 for palm oil. Esterification products were characterized by FT-IR. The FT-IR spectrum showed the ester bond was formed as indicated by the wave number 1739.79/cm. Esterification products have 2 substitution degrees.

  10. Arbuscular mycorrhiza Symbiosis Induces a Major Transcriptional Reprogramming of the Potato SWEET Sugar Transporter Family

    Science.gov (United States)

    Manck-Götzenberger, Jasmin; Requena, Natalia

    2016-01-01

    Biotrophic microbes feeding on plants must obtain carbon from their hosts without killing the cells. The symbiotic Arbuscular mycorrhizal (AM) fungi colonizing plant roots do so by inducing major transcriptional changes in the host that ultimately also reprogram the whole carbon partitioning of the plant. AM fungi obtain carbohydrates from the root cortex apoplast, in particular from the periarbuscular space that surrounds arbuscules. However, the mechanisms by which cortical cells export sugars into the apoplast for fungal nutrition are unknown. Recently a novel type of sugar transporter, the SWEET, able to perform not only uptake but also efflux from cells was identified. Plant SWEETs have been shown to be involved in the feeding of pathogenic microbes and are, therefore, good candidates to play a similar role in symbiotic associations. Here we have carried out the first phylogenetic and expression analyses of the potato SWEET family and investigated its role during mycorrhiza symbiosis. The potato genome contains 35 SWEETs that cluster into the same four clades defined in Arabidopsis. Colonization of potato roots by the AM fungus Rhizophagus irregularis imposes major transcriptional rewiring of the SWEET family involving, only in roots, changes in 22 of the 35 members. None of the SWEETs showed mycorrhiza-exclusive induction and most of the 12 induced genes belong to the putative hexose transporters of clade I and II, while only two are putative sucrose transporters from clade III. In contrast, most of the repressed transcripts (10) corresponded to clade III SWEETs. Promoter-reporter assays for three of the induced genes, each from one cluster, showed re-localization of expression to arbuscule-containing cells, supporting a role for SWEETs in the supply of sugars at biotrophic interfaces. The complex transcriptional regulation of SWEETs in roots in response to AM fungal colonization supports a model in which symplastic sucrose in cortical cells could be cleaved

  11. Arbuscular mycorrhiza Symbiosis Induces a Major Transcriptional Reprogramming of the Potato SWEET Sugar Transporter Family.

    Science.gov (United States)

    Manck-Götzenberger, Jasmin; Requena, Natalia

    2016-01-01

    Biotrophic microbes feeding on plants must obtain carbon from their hosts without killing the cells. The symbiotic Arbuscular mycorrhizal (AM) fungi colonizing plant roots do so by inducing major transcriptional changes in the host that ultimately also reprogram the whole carbon partitioning of the plant. AM fungi obtain carbohydrates from the root cortex apoplast, in particular from the periarbuscular space that surrounds arbuscules. However, the mechanisms by which cortical cells export sugars into the apoplast for fungal nutrition are unknown. Recently a novel type of sugar transporter, the SWEET, able to perform not only uptake but also efflux from cells was identified. Plant SWEETs have been shown to be involved in the feeding of pathogenic microbes and are, therefore, good candidates to play a similar role in symbiotic associations. Here we have carried out the first phylogenetic and expression analyses of the potato SWEET family and investigated its role during mycorrhiza symbiosis. The potato genome contains 35 SWEETs that cluster into the same four clades defined in Arabidopsis. Colonization of potato roots by the AM fungus Rhizophagus irregularis imposes major transcriptional rewiring of the SWEET family involving, only in roots, changes in 22 of the 35 members. None of the SWEETs showed mycorrhiza-exclusive induction and most of the 12 induced genes belong to the putative hexose transporters of clade I and II, while only two are putative sucrose transporters from clade III. In contrast, most of the repressed transcripts (10) corresponded to clade III SWEETs. Promoter-reporter assays for three of the induced genes, each from one cluster, showed re-localization of expression to arbuscule-containing cells, supporting a role for SWEETs in the supply of sugars at biotrophic interfaces. The complex transcriptional regulation of SWEETs in roots in response to AM fungal colonization supports a model in which symplastic sucrose in cortical cells could be cleaved

  12. Textural and sensory properties of spreads with sucrose and maltitol

    Directory of Open Access Journals (Sweden)

    Šoronja-Simović Dragana M.

    2012-01-01

    Full Text Available Spreads are confectionery products based on sugar, vegetable fat, cocoa powder, milk powder and other ingredients. Basic properties of these products are good spreadability in wide temperature range (from ambience to fridge temperature, rich creamy chocolate taste, and homogenous smooth structure without oil phase migration. Undesirable attribute of these products is their relatively high energy value (2300 kJ/100 g. In recent years, cocoa cream products with reduced energy values have become very popular among consumers and today they are present in the assortment of many confectionery manufacturers. One way to produce spreads with reduced energy value is the replacement of sugar (sucrose with adequate sweetener. Maltitol is a low-energy poliol capable to qualitatively and quantitatively replace sucrose. Cocoa spreads with maltitol and with the combination of maltitol and sucrose (produced at different temperatures and mixer rotation speeds have similar texture and rheological properties compared to the spreads with sucrose. The spreads with maltitol have about 15% lower energy value in comparison to the same product with sucrose.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Arabidopsis in Wageningen

    OpenAIRE

    Koornneef, M

    2013-01-01

    Arabidopsis thaliana is the plant species that in the past 25 years has developed into the major model species in plant biology research. This was due to its properties such as short generation time, its small genome and its easiness to be transformed. Wageningen University has played an important role in the development of this model, based on interdisciplinary collaborations using genetics as a major tool to investigate aspects of physiology, development, plant-microbe interactions and evol...

  15. Melatonin induces the transcripts of CBF/DREB1s and their involvement in both abiotic and biotic stresses in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Qian, Yongqiang; Tan, Dun-Xian; Reiter, Russel J; He, Chaozu

    2015-10-01

    Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule that acts as an important secondary messenger in plant stress responses. However, the mechanism underlying the melatonin-mediated signaling pathway in plant stress responses has not been established. C-repeat-binding factors (CBFs)/Drought response element Binding 1 factors (DREB1s) encode transcription factors that play important roles in plant stress responses. This study has determined that endogenous melatonin and transcripts level of CBFs (AtCBF1, AtCBF2, and AtCBF3) in Arabidopsis leaves were significantly induced by salt, drought, and cold stresses and by pathogen Pseudomonas syringe pv. tomato (Pst) DC3000 infection. Moreover, both exogenous melatonin treatment and overexpression of CBFs conferred enhanced resistance to both abiotic and biotic stresses in Arabidopsis. Notably, AtCBFs and exogenous melatonin treatment positively regulated the mRNA expression of several stress-responsive genes (COR15A, RD22, and KIN1) and accumulation of soluble sugars content such as sucrose in Arabidopsis under control and stress conditions. Additionally, exogenous sucrose also conferred improved resistance to both abiotic and biotic stresses in Arabidopsis. Taken together, this study indicates that AtCBFs confer enhanced resistance to both abiotic and biotic stresses, and AtCBF-mediated signaling pathway and sugar accumulation may be involved in melatonin-mediated stress response in Arabidopsis, at least partially. PMID:26182834

  16. The proteome and phosphoproteome of Neurospora crassa in response to cellulose, sucrose and carbon starvation

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Yi; Coradetti, Samuel T.; Li, Xin; Gritsenko, Marina A.; Clauss, Therese RW; Petyuk, Vladislav A.; Camp, David G.; Smith, Richard D.; Cate, Jamie H.; Yang, Feng; Glass, Louise

    2014-11-01

    Improving cellulolytic enzyme production by plant biomass degrading fungi holds great potential in reducing costs associated with production of next-generation biofuels generated from lignocellulose. How fungi sense cellulosic materials and respond by secreting enzymes has mainly been examined by assessing function of transcriptional regulators and via transcriptional profiling. Here, we obtained global proteomic and phosphoproteomic profiles of the plant biomass degrading filamentous fungus Neurospora crassa grown on different carbon sources, i.e. sucrose, no carbon, and cellulose, by performing isobaric tags for relative and absolute quantification (iTRAQ) -based LC-MS/MS analyses. A comparison between proteomes and transcriptomes under identical carbon conditions suggests that extensive post-transcriptional regulation occurs in N. crassa in response to exposure to cellulosic material. Several hundred amino acid residues with differential phosphorylation levels on crystalline cellulose (Avicel) or carbon-free medium versus sucrose medium were identified, including phosphorylation sites in a major transcriptional activator for cellulase genes, CLR1, as well as a cellobionic acid transporter, CBT1. Mutation of phosphorylation sites on CLR1 did not have a major effect on transactivation of cellulase production, while mutation of phosphorylation sites in CBT1 increased its transporting capacity. Our data provides rich information at both the protein and phosphorylation levels of the early cellular responses to carbon starvation and cellulosic induction and aids in a greater understanding of the underlying post-transcriptional regulatory mechanisms in filamentous fungi.

  17. A kinetic and microautoradiographic study of 14C-sucrose translocation into developing wheat grains

    International Nuclear Information System (INIS)

    The kinetics of 14C-photosynthate import by developing wheat grains was followed after pulse-labeling the flag leaf with 14CO2. Samples were collected from four successive points along the transport pathway to and within the grain: exuding aphid stylets on the peduncle, exuding grain pedicels, the grain crease tissues, and the liquid contents of the endosperm cavity. In addition, microautoradiographs were prepared of the grain crease tissues during movement of the 14C pulse into the grain. At all times, sucrose accounted for 93 to 97% of the total 14C present at all four sampling sites. The main features of the 14C kinetics could be accounted for by a simple compartmental model consisting of sucrose pools in series. Microautoradiographs of the crease tissues showed fairly uniform labeling of vascular parenchyma at all times, with a sharp gradient in labeling across the chalaza to the nucellus. Thus the principal resistance to post-phloem solute transport through the maternal tissues appears to be in the symplastic pathway across the chalaza

  18. Novel Unsaturated Sucrose Ethers and Their Application as Monomers

    Directory of Open Access Journals (Sweden)

    Maria T. Barros

    2007-03-01

    Full Text Available Novel unsaturated ethers were synthesised in good yields starting from sucrose,using a two-step mild and efficient procedure based on the Gassman method, whichconsists in forming a vinyl group by the elimination of ethanol from mixed acetals withtrimethylsilyl trifluoromethanesulfonate in the presence of alkyl amines. Mixed acetals arereadily obtained from the corresponding alcohols and ethyl vinyl ether, using an acidiccatalyst. Conventional etherification involving a primary halide was also examined. Themonomers thus obtained were successfully polymerised by a free radical mechanism,yielding unbranched linear and soluble polymers with pending sucrose moieties, and someof their physical properties were determined.

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

    Science.gov (United States)

    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.

  20. Structural analyses of sucrose laurate regioisomers by mass spectrometry techniques

    DEFF Research Database (Denmark)

    Lie, Aleksander; Stensballe, Allan; Pedersen, Lars Haastrup

    2015-01-01

    6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore the physic......6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore...

  1. Sucrose: A Prospering and Sustainable Organic Raw Material

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Anharmonicity and hydrogen bonding in electrooptic sucrose crystal

    Science.gov (United States)

    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.

  4. Analysis of sucrose acetates in a crude 6-O-acetyl sucrose product by on-line hydrolysis-high-performance liquid chromatography with pulsed amperometric detection.

    Science.gov (United States)

    Yan, Wenwu; Wang, Nani; Zhang, Peimin; Zhang, Jiajie; Wu, Shuchao; Zhu, Yan

    2016-06-01

    A standard-free and sensitive method was developed for analysis of sucrose acetates in a crude 6-O-acetyl sucrose (S-6-a) product by on-line hydrolysis-high-performance liquid chromatography with pulsed amperometric detection (PAD). Sucrose, three regio-isomers of acetyl sucrose and five regio-isomers of diacetyl sucrose were separated on a C18 column using 3% (v/v) acetonitrile in water as eluent within 25min. After purification with LC followed by semi-preparative HPLC, their chemical structures were identified by 1D, 2D NMR and LC-MS. Moreover, quantification of those regio-isomers was achieved by on-line alkaline hydrolysis to liberate sucrose using a post-column delivery system, and then detected by PAD for indirect estimation of the sucrose acetate content. Under optimal conditions, the linear ranges were from 0.03 to 150μmolL(-1) for sucrose corresponding to sucrose acetates with coefficient of determination as 0.9997 and detection limit as 0.01μmolL(-1) (S/N=3). Good repeatability was obtained (RSDpurification and structure elucidation studies. The recoveries were from 94.89% to 102.31% for sucrose and sucrose acetates. PMID:27139218

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

    Science.gov (United States)

    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

  6. The SWEET family of sugar transporters in grapevine: VvSWEET4 is involved in the interaction with Botrytis cinerea.

    Science.gov (United States)

    Chong, Julie; Piron, Marie-Christine; Meyer, Sophie; Merdinoglu, Didier; Bertsch, Christophe; Mestre, Pere

    2014-12-01

    During plant development, sugar export is determinant in multiple processes such as nectar production, pollen development and long-distance sucrose transport. The plant SWEET family of sugar transporters is a recently identified protein family of sugar uniporters. In rice, SWEET transporters are the target of extracellular bacteria, which have evolved sophisticated mechanisms to modify their expression and acquire sugars to sustain their growth. Here we report the characterization of the SWEET family of sugar transporters in Vitis vinifera. We identified 17 SWEET genes in the V. vinifera 40024 genome and show that they are differentially expressed in vegetative and reproductive organs. Inoculation with the biotrophic pathogens Erysiphe necator and Plasmopara viticola did not result in significant induction of VvSWEET gene expression. However, infection with the necrotroph Botrytis cinerea triggered a strong up-regulation of VvSWEET4 expression. Further characterization of VvSWEET4 revealed that it is a glucose transporter localized in the plasma membrane that is up-regulated by inducers of reactive oxygen species and virulence factors from necrotizing pathogens. Finally, Arabidopsis knockout mutants in the orthologous AtSWEET4 were found to be less susceptible to B. cinerea. We propose that stimulation of expression of a developmentally regulated glucose uniporter by reactive oxygen species production and extensive cell death after necrotrophic fungal infection could facilitate sugar acquisition from plant cells by the pathogen. PMID:25246444

  7. Analysis of mRNA translation states in Arabidopsis over the diurnal cycle by polysome microarray.

    Science.gov (United States)

    Missra, Anamika; von Arnim, Albrecht G

    2014-01-01

    Gene regulation at the level of translation occurs in response to environmental perturbation and is increasingly recognized as a factor affecting plant development. Despite extensive knowledge of transcriptional control, very little is known about translational regulation of genes in response to the daily light/dark cycles. Here we describe the experimental layout designed to address how the translation states of genes change at various times during a diurnal cycle in Arabidopsis thaliana seedlings. We have adopted a strategy combining sucrose-gradient profiling of ribosomes and high-throughput microarray analysis of the ribosome-associated mRNA to investigate the translational landscape of the Arabidopsis genome. This is a powerful technique that can be easily extended to study translation regulation in different genetic backgrounds and under various environmental conditions. PMID:24792050

  8. Effect of carbon/nitrogen ratio on carbohydrate metabolism and light energy dissipation mechanisms in Arabidopsis thaliana.

    Science.gov (United States)

    Huarancca Reyes, Thais; Scartazza, Andrea; Lu, Yu; Yamaguchi, Junji; Guglielminetti, Lorenzo

    2016-08-01

    Carbon (C) and nitrogen (N) nutrient sources are essential elements for metabolism, and their availability must be tightly coordinated for the optimal growth and development in plants. Plants are able to sense and respond to different C/N conditions via specific partitioning of C and N sources and the regulation of a complex cellular metabolic activity. We studied how the interaction between C and N signaling could affect carbohydrate metabolism, soluble sugar levels, photochemical efficiency of photosystem II (PSII) and the ability to drive the excess energy in Arabidopsis seedlings under moderated and disrupted C/N-nutrient conditions. Invertase and sucrose synthase activities were markedly affected by C/N-nutrient status depending on the phosphorylation status, suggesting that these enzymes may necessarily be modulated by their direct phosphorylation or phosphorylation of proteins that form complex with them in response to C/N stress. In addition, the enzymatic activity of these enzymes was also correlated with the amount of sugars, which not only act as substrate but also as signaling compounds. Analysis of chlorophyll fluorescence in plants under disrupted C/N condition suggested a reduction of electron transport rate at PSII level associated with a higher capacity for non-radiative energy dissipation in comparison with plants under moderated C/N condition. In conclusion, the tight coordination between C and N not only affects the carbohydrates metabolism and their concentration within plant tissues, but also the partitioning of the excitation energy at PSII level between radiative (electron transport) and non-radiative (heat) dissipation pathways. PMID:27108206

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

    Science.gov (United States)

    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,…

  10. An Arabidopsis callose synthase

    DEFF Research Database (Denmark)

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole;

    2002-01-01

    unclear whether callose synthases can also produce cellulose and whether plant cellulose synthases may also produce beta-1,3-glucans. We describe here an Arabidopsis gene, AtGsl5, encoding a plasma membrane-localized protein homologous to yeast beta-1,3-glucan synthase whose expression partially......Beta-1,3-glucan polymers are major structural components of fungal cell walls, while cellulosic beta-1,4-glucan is the predominant polysaccharide in plant cell walls. Plant beta-1,3-glucan, called callose, is produced in pollen and in response to pathogen attack and wounding, but it has been...

  11. Metabolic footprint of epiphytic bacteria on Arabidopsis thaliana leaves.

    Science.gov (United States)

    Ryffel, Florian; Helfrich, Eric Jn; Kiefer, Patrick; Peyriga, Lindsay; Portais, Jean-Charles; Piel, Jörn; Vorholt, Julia A

    2016-03-01

    The phyllosphere, which is defined as the parts of terrestrial plants above the ground, is a large habitat for different microorganisms that show a high extent of adaption to their environment. A number of hypotheses were generated by culture-independent functional genomics studies to explain the competitiveness of specialized bacteria in the phyllosphere. In contrast, in situ data at the metabolome level as a function of bacterial colonization are lacking. Here, we aimed to obtain new insights into the metabolic interplay between host and epiphytes upon colonization of Arabidopsis thaliana leaves in a controlled laboratory setting using environmental metabolomics approaches. Quantitative nuclear magnetic resonance (NMR) and imaging high-resolution mass spectrometry (IMS) methods were used to identify Arabidopsis leaf surface compounds and their possible involvement in the epiphytic lifestyle by relative changes in compound pools. The dominant carbohydrates on the leaf surfaces were sucrose, fructose and glucose. These sugars were significantly and specifically altered after epiphytic leaf colonization by the organoheterotroph Sphingomonas melonis or the phytopathogen Pseudomonas syringae pv. tomato, but only to a minor extent by the methylotroph Methylobacterium extorquens. In addition to carbohydrates, IMS revealed surprising alterations in arginine metabolism and phytoalexin biosynthesis that were dependent on the presence of bacteria, which might reflect the consequences of bacterial activity and the recognition of not only pathogens but also commensals by the plant. These results highlight the power of environmental metabolomics to aid in elucidating the molecular basis underlying plant-epiphyte interactions in situ. PMID:26305156

  12. In vivo measurements of sulcal plaque pH in rats after topical applications of xylitol, sorbitol, glucose, sucrose, and sucrose plus 53 mM sodium fluoride.

    Science.gov (United States)

    Firestone, A R; Navia, J M

    1986-01-01

    In two series of experiments, Sprague-Dawley-derived rats were infected orally with cariogenic micro-organisms and fed caries-promoting diets. By means of an antimony electrode, resting pH values were measured in the mesial sulcus of the maxillary left first molar. 100 or 200 microL of the test solutions were applied, and the change in pH (delta pH) was recorded for three min. Test solutions were: (a) 10% sucrose, 10% glucose, 10% sorbitol, or 10% xylitol; (b) 0%, 10%, 20%, or 40% sucrose; (c) 0%, 3%, 7%, or 10% sucrose; and (d) 10% sucrose, 10% sucrose + 53 mmol/L NaF (1000 ppmF-), or 10% sucrose + 53 mmol/L NaCl. Experimental design was a 4 X 4 Latin square (a, b, c) or a cross-over design (d). Solutions of sucrose and glucose gave significantly greater decreases in pH than did sorbitol or xylitol. pH fall was maximal for 10% sucrose and significantly less for 40% sucrose during the three-minute experimental period. For sucrose solutions ranging in concentration from 3 to 10%, pH fall was highest after application of 10% sucrose when plaque was previously rinsed with water, but this pH fall did not differ significantly from that obtained using a 7% sucrose solution. Adding 1000 ppmF- to a 10% sucrose solution caused an increase in pH. Rinsing the teeth to remove saliva resulted in significantly lower resting pH values. The results of these experiments are in agreement with the results of human plaque pH measurements. PMID:3455697

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

    Science.gov (United States)

    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.

  14. Photorepair mutants of Arabidopsis

    International Nuclear Information System (INIS)

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  15. Structural insights into the cubic-hexagonal phase transition kinetics of monoolein modulated by sucrose solutions

    OpenAIRE

    Reese, Caleb W.; Strango, Zachariah I.; Dell, Zachary R.; Tristram-Nagle, Stephanie; Harper, Paul E.

    2015-01-01

    Using DSC (differential scanning calorimetry), we measure the kinetics of the cubic-HII phase transition of monoolein in bulk sucrose solutions. We find that the transition temperature is dramatically lowered, with each 1 mol/kg of sucrose concentration dropping the transition by 20 °C. The kinetics of this transition also slow greatly with increasing sucrose concentration. For low sucrose concentrations, the kinetics are asymmetric, with the cooling (HII-cubic) transition taking twice as lon...

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

    Science.gov (United States)

    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…

  17. Transgenic Arabidopsis Gene Expression System

    Science.gov (United States)

    Ferl, Robert; Paul, Anna-Lisa

    2009-01-01

    The Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors (an organism used to determine the quality of the surrounding environment) of their environment using real-time nondestructive Green Fluorescent Protein (GFP) imagery and traditional postflight analyses.

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

    Science.gov (United States)

    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

  19. Sucrose solution freezing studied by magnetic resonance imaging.

    Science.gov (United States)

    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

  20. Characterization of Ion Contents and Metabolic Responses to Salt Stress of Different Arabidopsis AtHKT1;1 Genotypes and Their Parental Strains

    Institute of Scientific and Technical Information of China (English)

    Camilla B.Hill; Deepa Jha; Antony Bacic; Mark Tester; Ute Roessner

    2013-01-01

    Plants employ several strategies to maintain cellular ion homeostasis under salinity stress,including mediating ion fluxes by transmembrane transport proteins and adjusting osmotic pressure by accumulating osmolytes.The HKT (high-affinity potassium transporter) gene family comprises Na+ and Na+/K+ transporters in diverse plant species,with HKT1;1 as the only member in Arabidopsis thaliana.Cell-type-specific overexpression of AtHKT1;1 has been shown to prevent shoot Na+ overaccumulation under salinity stress.Here,we analyzed a broad range of metabolites and elements in shoots and roots of different AtHKT1;1 genotypes and their parental strains before and after salinity stress,revealing a reciprocal relationship of metabolite differences between an AtHKT1;1 knockout line (hktl;1) and the AtHKT1;1 overexpressing lines (E2586 UASGAL4:HKT1;1 and J2731*UASGAL4:HKT1;1).Although levels of root sugars were increased after salt stress in both AtHKT1;1 overexpressing lines,E2586 UASGAL4:HKT1;1 showed higher accumulation of the osmoprotectants trehalose,gentiobiose,and melibiose,whereas J2731*UASGAL4:HKT1;1 showed higher levels of sucrose and raffinose,compared with their parental lines,respectively.In contrast,the knockout line hktl;1 showed strong increases in the levels of the tricarboxylic acid (TCA) cycle intermediates in the shoots after salt treatment.This coincided with a significant depletion of sugars,suggesting that there is an increased rate of carbon influx into the TCA cycle at a constant rate of C-efflux from the cycle,which might be needed to support plant survival during salt stress.Using correlation analysis,we identified associations between the Na+ content and several sugars,suggesting that regulation of sugar metabolism is important in plant responses to salinity stress.

  1. Metabolic Fluxes in Corynebacterium glutamicum during Lysine Production with Sucrose as Carbon Source

    OpenAIRE

    Wittmann, Christoph; Kiefer, Patrick; Zelder, Oskar

    2004-01-01

    Metabolic fluxes in the central metabolism were determined for lysine-producing Corynebacterium glutamicum ATCC 21526 with sucrose as a carbon source, providing an insight into molasses-based industrial production processes with this organism. For this purpose, 13C metabolic flux analysis with parallel studies on [1-13CFru]sucrose, [1-13CGlc]sucrose, and [13C6Fru]sucrose was carried out. C. glutamicum directed 27.4% of sucrose toward extracellular lysine. The strain exhibited a relatively hig...

  2. Auxin regulates distal stem cell differentiation in Arabidopsis roots

    OpenAIRE

    Ding, Zhaojun; Friml, Jiří

    2010-01-01

    The stem cell niche in the root meristem is critical for the development of the plant root system. The plant hormone auxin acts as a versatile trigger in many developmental processes, including the regulation of root growth, but its role in the control of the stem cell activity remains largely unclear. Here we show that local auxin levels, determined by biosynthesis and intercellular transport, mediate maintenance or differentiation of distal stem cells in the Arabidopsis thaliana roots. Gene...

  3. Segmenting the sepal and shoot apical meristem of Arabidopsis thaliana

    OpenAIRE

    Cunha, Alexandre L.; Roeder, Adrienne H. K.; Meyerowitz, Elliot M.

    2010-01-01

    We present methods for segmenting the sepal and shoot apical meristem of the Arabidopsis thaliana plant. We propose a mathematical morphology pipeline and a modified numerical scheme for the active contours without edges algorithm to extract the geometry and topology of plant cells imaged using confocal laser scanning microscopy. We demonstrate our methods in typical images used in the studies of cell endoreduplication and hormone transport and show that in practice they produce highly accura...

  4. Sucrose polyesters from poultry fat as non-ionic emulsifiers

    Directory of Open Access Journals (Sweden)

    Megahed, Mohamed G.

    2000-12-01

    Full Text Available Poultry fats are rich in palmitic and oleic acids are produced as by-products from poultry industries. These fats can be utilized in the preparation of emulsifiers. Sucrose esters of poultry fat are prepared from low-cost poultry fat and sucrose by esterification. The yield of sucrose esters prepared in this work exceeds than 85%. The hydrophilic-lipophilic balance (HLB, surface tension, interfacial tension and stability index (SI were evaluated and compared with standard emulsifiers prepared from pure palmitate and oleate esters. Concerning the stability of emulsions, the values of interfacial tension and HLB were higher for the sucrose esters of poultry fat.Las grasas de aves de corral son ricas en ácidos palmítico y oleico y son producidas como subproductos de las industrias avícolas. Estas grasas pueden ser utilizadas en la preparación de emulsionantes. Los ésteres de sacarosa de grasas de aves de corral fueron preparadas a partir de grasas de bajo coste y sacarosa por esterificación. El rendimiento de los ésteres de sacarosa preparados en este trabajo superó el 85%. El balance hidrofílicolipofílico (HLB, tensión superficial, tensión interfacial e índice de estabilidad (SI fueron evaluados y comparados con emulsionantes estandar preparados de ésteres de palmitato y oleato puros. Los valores de tensión interfacial y el HLB fueron más altos en los poliésteres de sacarosa de las grasas de aves de corral.

  5. INTRAVENOUS IRON SUCROSE THERAPY IN ANEMIA WITH PREGNANCY

    Directory of Open Access Journals (Sweden)

    Swami

    2015-08-01

    Full Text Available Anemia of pregnancy is most common medical disorder in the developing country, affecting 2 billion population worldwide. In India prevalence is 49.7% of pregnancy contributing to 80% of maternal mortality. Parental iron therapy produces rapid, complete correction of iron deficiency including iron stores. Intravenous iron sucrose therapy has become gold standard in management. It has many advantages over other iron preparations in correction of anemia. AIMS AND OBJECTIVE: Evaluation of hemoglobin improvement, time required, and patient’s compliance after iron sucrose therapy. MATERIAL AND METHODS: Retrospective analysis was done of 264 pregnant women with anemia who were admitted in R. D. Gardi Medical College Ujjain M. P. from M ay 2012 to August 2014, and were diagnosed as iron deficiency anemia and had received intravenous iron sucrose 200 mg weekly till targeted hemoglobin 10gm was reached. RESULTS: majority of women (54.2% were in age group of 21 - 29 years. 66.3% were resident of rural area. Anemia was more common (69.7% in women with vegetarian diet. 83% 0f patients were multigravida. 48.9% cases were of mild, 44.7% of moderate, and 6.4 % of severe anemia. There was initial rise in Hb within a week and rise of 1 - 2gm Hb per week attaining a targeted Hb. CONCLUSION: Iron sucrose is the best tolerated drug, gives mean Hb rise by 600 mg in all grades of anemia and in maximum periods of 4 weeks. Looking at the patient’s compliance and feasibility this drug has replaced strategy of unnecessary blood transfusions.

  6. Fatal anaphylactic reaction to iron sucrose in pregnancy

    OpenAIRE

    Ajay Mishra; Nikhil Dave; Kishor Viradiya

    2013-01-01

    Iron-deficiency anemia in pregnancy can have serious deleterious effects for both mother and fetus. Parenteral iron therapy in iron-deficiency anemia is recommended in patients where oral iron therapy is ineffective due to malabsorption states and non-compliance. Compared to oral iron therapy, intravenous iron results in much more rapid resolution of iron-deficiency anemia with minimal adverse reactions. Iron sucrose has a favorable safety profile and is an alternative to other forms of paren...

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  10. The H+-sucrose cotransporter NtSUT1 is essential for sugar export from tobacco leaves

    International Nuclear Information System (INIS)

    In many species translocation of sucrose from the mesophyll to the phloem is carrier mediated. A sucrose/H+-symporter cDNA, NtSUT1, was isolated from tobacco (Nicotiana tabacum) and shown to be highly expressed in mature leaves and at low levels in other tissues, including floral organs. To study the in vivo function of NtSUT1, tobacco plants were transformed with a SUT1 antisense construct under control of the cauliflower mosaic virus 355 promoter. Upon maturation, leaves of transformants expressing reduced amounts of SUT1 mRNA curled downward, and strongly affected plants developed chloroses and necroses that led to death. The leaves exhibited impaired ability to export recently fixed 14CO2 and were unable to export transient starch during extended periods of darkness. As a consequence, soluble carbohydrates accumulated and photosynthesis was reduced. Autoradiographs of leaves show a heterogenous pattern of CO2 fixation even after a 24-h chase. The 14C pattern does not change with time, suggesting that movement of photosynthate between mesophyll cells may also be impaired. The affected lines show a reduction in the development of the root system and delayed or impaired flowering. Taken together, the effects observed in a seed plant (tobacco) demonstrate the importance of SUT1 for sucrose loading into the phloem via an apoplastic route and possibly for intermesophyll transport as well

  11. What´s cheapest, intravenous iron sucrose- or intravenous iron carboxymaltose treatment in IBD patients?

    DEFF Research Database (Denmark)

    Bager, Palle; Dahlerup, Jens Frederik

    , utensils and ½ hour spend by a nurse per visit; showed approximately 150€ extra cost per 1000 mg Fe++ administrated, if iron carboxymaltose was chosen. In contrast the CEA including both BIA-values and patient-related costs (transportation and lost income) showed iron carboxymaltose to be more cost......®, Vifor) treatment to IBD patients in an outpatient setting.   Background: Intravenous iron sucrose can be given as a maximum of 200 mg Fe++ per infusion vs. intravenous iron carboxymaltose that can be given as a maximum of 1000 mg Fe++ in a single infusion leading to fewer infusions and visits. The drug......++ till 1600 mg Fe++. The WTP analysis was based on a total infusion-dose at 1400 mg Fe++. The evaluations are analysed assuming that the effect parameter (quantity of iron delivered) is comparable regardless of the iron formulation given intravenously.   Results: The BIA including price for drug...

  12. Impact of Sucrose Concentrations on in vitro Pollen Germination of Okra, Hibiscus esculentus

    Directory of Open Access Journals (Sweden)

    Mohammed Jurial Baloch

    2001-01-01

    Full Text Available Exogenous sugars, especially sucrose is very essential for providing osmotic environment and nutrition to in vitro pollen grain germination. Pollen bursting is frequently observed in artificial medium lacking suitable sucrose concentration. Four sucrose concentrations 10, 20, 30 and 40% were tried for okra pollen germination. At 10% sucrose,majority of pollens brusted; however, at 20% sucrose, 80% ofpollen grains germinated by producing tube lengths in the range of 3000 to 4000 μm. At 30%, the pollen germination% and tube length declined by about more thantwice against 20% sucrose level. At 40% concentrations, pollen grains` germination and tube length reduced remarkably by giving only500 to 700 μm pollen tubes. Not only tube length retarded at these high concentrations but pollentubes also changed to more thickened and shortened structures.It was therefore observed that 20% sucrose is an appropriate concentration for in vitro okra pollen germination.

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

    International Nuclear Information System (INIS)

    Highlights: ► Hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. ► The sucrose added ZnO flowers showed improved activity mainly due to the improved crystallinity. ► The effect of sucrose content was studied and optimized. - Abstract: 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.

  14. Anti-obesity effect of Lactobacillus gasseri BNR17 in high-sucrose diet-induced obese mice.

    Directory of Open Access Journals (Sweden)

    Ji-Hee Kang

    Full Text Available Previously, we reported that Lactobacillus gasseri BNR17 (BNR17, a probiotic strain isolated from human breast milk, inhibited increases in body weight and adipocyte tissue weight in high-sucrose diet-fed Sprague-Dawley (SD rats and reduced glucose levels in type 2 diabetes mice. In the current study, we conducted further experiments to extend these observations and elucidate the mechanism involved. C57BL/6J mice received a normal diet, high-sucrose diet or high-sucrose diet containing L. gasseri BNR17 (10(9 or 10(10 CFU for 10 weeks. The administration of L. gasseri BNR17 significantly reduced the body weight and white adipose tissue weight regardless of the dose administered. In BNR17-fed groups, mRNA levels of fatty acid oxidation-related genes (ACO, CPT1, PPARα, PPARδ were significantly higher and those of fatty acid synthesis-related genes (SREBP-1c, ACC were lower compared to the high-sucrose-diet group. The expression of GLUT4, main glucose transporter-4, was elevated in BNR17-fed groups. L. gasseri BNR17 also reduced the levels of leptin and insulin in serum. These results suggest that the anti-obesity actions of L. gasseri BNR17 can be attributed to elevated expression of fatty acid oxidation-related genes and reduced levels of leptin. Additionally, data suggested the anti-diabetes activity of L. gasseri BNR17 may be to due elevated GLUT4 and reduced insulin levels.

  15. Pioglitazone can ameliorate insulin resistance in low-dose streptozotocin and high sucrose-fat diet induced obese rats

    Institute of Scientific and Technical Information of China (English)

    Shi-ying DING; Zhu-fang SHEN; Yue-teng CHEN; Su-juan SUN; Quan Liu; Ming-zhi XIE

    2005-01-01

    Aim: To investigate the effect of the peroxisome proliferator-activator receptor (PPAR)-γ agonist, pioglitazone, on insulin resistance in low-dose streptozotocin and high sucrose-fat diet induced obese rats. Methods: Normal female Wistar rats were injected intraperitoneally with low-dose streptozotocin (STZ, 30 mg/kg) and fed with a high sucrose-fat diet for 8 weeks. Pioglitazone (20 mg/kg) was administered orally to the obese and insulin-resistant rats for 28 d. Intraperitoneal glucose tolerance tests, insulin tolerance tests and gluconeogenesis tests were carried out over the last 14 d. At the end of d 28 of the treatment, serums were collected for biochemical analysis. Glucose transporter 4 (GLUT4) and insulin receptor substrate-1 (IRS-1) protein expression in the liver and skeletal muscle were detected using Western blotting. Results: Significant insulin resistance and obesity were observed in low-dose STZ and high sucrose-fat diet induced obese rats. Pioglitazone (20 mg/kg) treatment significantly decreased serum insulin,triglyceride and free fatty acid levels, and elevated high density lipoprotein-cholesterol (HDL-C) levels. Pioglitazone also lowered the lipid contents in the liver and muscles of rats undergoing treatment. Gluconeogenesis was inhibited and insulin sensitivity was improved markedly. The IRS-1 protein contents in the liver and skeletal muscles and the GLUT4 contents in skeletal muscle were elevated significantly. Conclusion: The data suggest that treatment with pioglitazone improves insulin sensitivity in low-dose STZ and high sucrose-fat diet induced obese rats. The insulin sensitizing effect may be associated with ameliorating lipid metabolism, reducing hyperinsulinemia, inhibiting gluconeogenesis, and increasing IRS-1 and GLUT4 protein expression in insulin-sensitive tissues.

  16. Identification, cloning and characterization of sis7 and sis10 sugar-insensitive mutants of Arabidopsis

    Directory of Open Access Journals (Sweden)

    Biddle Kelly D

    2008-10-01

    Full Text Available Abstract Background The levels of soluble sugars, such as glucose and sucrose, help regulate many plant metabolic, physiological and developmental processes. Genetic screens are helping identify some of the loci involved in plant sugar response and reveal extensive cross-talk between sugar and phytohormone response pathways. Results A forward genetic screen was performed to identify mutants with increased resistance to the inhibitory effects of high levels of exogenous sugars on early Arabidopsis seedling development. The positional cloning and characterization of two of these sugar insensitive (sis mutants, both of which are also involved in abscisic acid (ABA biosynthesis or response, are reported. Plants carrying mutations in SIS7/NCED3/STO1 or SIS10/ABI3 are resistant to the inhibitory effects of high levels of exogenous Glc and Suc. Quantitative RT-PCR analyses indicate transcriptional upregulation of ABA biosynthesis genes by high concentrations of Glc in wild-type germinating seeds. Gene expression profiling revealed that a significant number of genes that are expressed at lower levels in germinating sis7-1/nced3-4/sto1-4 seeds than in wild-type seeds are implicated in auxin biosynthesis or transport, suggesting cross-talk between ABA and auxin response pathways. The degree of sugar insensitivity of different sis10/abi3 mutant seedlings shows a strong positive correlation with their level of ABA insensitivity during seed germination. Conclusion Mutations in the SIS7/NCED3/STO1 gene, which is primarily required for ABA biosynthesis under drought conditions, confer a sugar-insensitive phenotype, indicating that a constitutive role in ABA biosynthesis is not necessary to confer sugar insensitivity. Findings presented here clearly demonstrate that mutations in ABI3 can confer a sugar-insensitive phenotype and help explain previous, mixed reports on this topic by showing that ABA and sugar insensitivity exhibit a strong positive correlation in

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

    Science.gov (United States)

    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

  18. Crystallization and preliminary X-ray diffraction study of a cell-wall invertase from Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Crystals suitable for structural analysis have been prepared from a cell-wall invertase from A. thaliana. Cell-wall invertase 1 (AtcwINV1), a plant protein from Arabidopsis thaliana which is involved in the breakdown of sucrose, has been crystallized in two different crystal forms. Crystal form I grows in space group P31 or P32, whereas crystal form II grows in space group C2221. Data sets were collected for crystal forms I and II to resolution limits of 2.40 and 2.15 Å, respectively

  19. On the role of a Lipid-Transfer Protein. Arabidopsis ltp3 mutant is compromised in germination and seedling growth.

    OpenAIRE

    Pagnussat, Luciana A; Oyarburo, Natalia; Cimmino, Carlos; Pinedo, Marcela L; de la Canal, Laura

    2015-01-01

    Plant Lipid-Transfer Proteins (LTPs) exhibit the ability to reversibly bind/transport lipids in vitro. LTPs have been involved in diverse physiological processes but conclusive evidence on their role has only been presented for a few members, none of them related to seed physiology. Arabidopsis seeds rely on storage oil breakdown to supply carbon skeletons and energy for seedling growth. Here, Arabidopsis ltp3 mutant was analyzed for its ability to germinate and for seedling establishment. Lt...

  20. CvADH1, a member of short-chain alcohol dehydrogenase family, is inducible by gibberellin and sucrose in developing watermelon seeds.

    Science.gov (United States)

    Kim, Joonyul; Kang, Hong-Gyu; Jun, Sung-Hoon; Lee, Jinwon; Yim, Jieun; An, Gynheung

    2003-01-01

    To understand the molecular mechanisms that control seed formation, we selected a seed-preferential gene (CvADH1) from the ESTs of developing watermelon seeds. RNA blot analysis and in situ localization showed that CvADH1 was preferentially expressed in the nucellar tissue. The CvADH1 protein shared about 50% homology with short-chain alcohol dehydrogenase including ABA2 in Arabidopsis thaliana, stem secoisolariciresinol dehydrogenase in Forsythia intermedia, and 3beta-hydroxysterol dehydrogenase in Digitalis lanata. We investigated gene-expression levels in seeds from both normally pollinated fruits and those made parthenocarpic via N-(2-chloro-4-pyridyl)-N'-phenylurea treatment, the latter of which lack zygotic tissues. Whereas the transcripts of CvADH1 rapidly started to accumulate from about the pre-heart stage in normal seeds, they were not detectable in the parthenocarpic seeds. Treating the parthenogenic fruit with GA(3) strongly induced gene expression, up to the level accumulated in pollinated seeds. These results suggest that the CvADH1 gene is induced in maternal tissues by signals made in the zygotic tissues, and that gibberellin might be one of those signals. We also observed that CvADH1 expression was induced by sucrose in the parthenocarpic seeds. Therefore, we propose that the CvADH1 gene is inducible by gibberellin, and that sucrose plays an important role in the maternal tissues of watermelon during early seed development. PMID:12552151

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

    Science.gov (United States)

    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

  2. Characterization of Sugar Insensitive (sis) Mutants of Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Susan I.

    2009-06-08

    Despite the fact that soluble sugar levels have been postulated to play an important role in the control of a wide variety of plant metabolic and developmental pathways, the mechanisms by which plants respond to soluble sugar levels remain poorly understood. Plant responses to soluble sugar levels are also important in bioenergy production, as plant sugar responses are believed to help regulate both carbon fixation and carbon partitioning. For example, accumulation of soluble sugars, such as sucrose and glucose, in source tissues leads to feedback inhibition of photosynthesis, thereby decreasing rates of carbon fixation. Soluble sugar levels can also affect sink strengths, affecting the rates of accumulation of carbon-based compounds into both particular molecular forms (e.g. carbohydrates versus lipids versus proteins) and particular plant organs and tissues. Mutants of Arabidopsis that are defective in the ability to respond to soluble sugar levels were isolated and used as tools to identify some of the factors involved in plant sugar response. These sugar insensitive (sis) mutants were isolated by screening mutagenized seeds for those that were able to germinate and develop relatively normal shoot systems on media containing 0.3 M glucose or 0.3 M sucrose. At these sugar concentrations, wild-type Arabidopsis germinate and produce substantial root systems, but show little to no shoot development. Twenty-eight sis mutants were isolated during the course of four independent mutant screens. Based on a preliminary characterization of all of these mutants, sis3 and sis6 were chosen for further study. Both of these mutations appear to lie in previously uncharacterized loci. Unlike many other sugar-response mutants, sis3 mutants exhibit a wild-type or near wild-type response in all phytohormone-response assays conducted to date. The sis6-1 mutation is unusual in that it appears to be due to overexpression of a gene, rather than representing a loss of function mutation

  3. Protective mechanism of desiccation tolerance in Reaumuria soongorica: Leaf abscission and sucrose accumulation in the stem

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Reaumuria soongorica (Pall.) Maxim., a perennial semi-shrub, is widely found in semi-arid areas in northwestern China and can survive severe desiccation of its vegetative organs. In order to study the protective mechanism of desiccation tolerance in R. soongorica, diurnal patterns of net photosynthetic rate (Pn), water use efficiency (WUE) and chlorophyll fluorescence parameters of Photosystem II (PSII), and sugar content in the source leaf and stem were investigated in 6-year-old plants during progressive soil drought imposed by the cessation of watering. The results showed that R. soongorica was char-acterized by very low leaf water potential, high WUE, photosynthesis and high accumulation of sucrose in the stem and leaf abscission under desiccation. The maximum Pn increased at first and then de-clined during drought, but intrinsic WUE increased remarkably in the morning with increasing drought stress. The maximal photochemical efficiency of PSII (Fv/Fm) and the quantum efficiency of noncyclic electric transport of PSII(ΦPSII) decreased significantly under water stress and exhibited an obvious phenomenon of photoinhibition at noon. Drought stressed plants maintained a higher capacity of dis-sipation of the excitation energy (measured as NPQ) with the increasing intensity of stress. Conditions of progressive drought promoted sucrose and starch accumulation in the stems but not in the leaves. However, when leaf water potential was less than –21.3 MPa, the plant leaves died and then abscised. But the stem photosynthesis remained and, afterward the plants entered the dormant state. Upon re-watering, the shoots reactivated and the plants developed new leaves. Therefore, R. soongorica has the ability to reduce water loss through leaf abscission and maintain the vigor of the stem cells to survive desiccation.

  4. Protective mechanism of desiccation tolerance in Reaumuria soongorica: Leaf abscission and sucrose accumulation in the stem

    Institute of Scientific and Technical Information of China (English)

    LIU YuBing; ZHANG TengGuo; LI XingRong; WANG Gang

    2007-01-01

    Reaumuria soongorica (Pall.) Maxim., a perennial semi-shrub, is widely found in semi-arid areas in northwestern China and can survive severe desiccation of its vegetative organs. In order to study the protective mechanism of desiccation tolerance in R. Soongorica, diurnal patterns of net photosynthetic rate (Pn), water use efficiency (WUE) and chlorophyll fluorescence parameters of Photosystem II (PSII), and sugar content in the source leaf and stem were investigated in 6-year-old plants during progressive soil drought imposed by the cessation of watering. The results showed that R. Soongorica was characterized by very low leaf water potential, high WUE, photosynthesis and high accumulation of sucrose in the stem and leaf abscission under desiccation. The maximum Pn increased at first and then declined during drought, but intrinsic WUE increased remarkably in the morning with increasing drought stress. The maximal photochemical efficiency of PSII (Fv/Fm) and the quantum efficiency of noncyclic electric transport of PSII(Φpsii) decreased significantly under water stress and exhibited an obvious phenomenon of photoinhibition at noon. Drought stressed plants maintained a higher capacity of dissipation of the excitation energy (measured as NPQ) with the increasing intensity of stress. Conditions of progressive drought promoted sucrose and starch accumulation in the stems but not in the leaves. However, when leaf water potential was less than -21.3 Mpa, the plant leaves died and then abscised. But the stem photosynthesis remained and, afterward the plants entered the dormant state. Upon rewatering, the shoots reactivated and the plants developed new leaves. Therefore, R. Soongorica has the ability to reduce water loss through leaf abscission and maintain the vigor of the stem cells to survive desiccation.

  5. Deer Frozen Semen Quality in Tris Sucrose and Tris Glucose Extender with Different Glycerol Concentrations

    OpenAIRE

    W. M. M. Nalley; R. Handarini; R.I Arifiantini; T.L. Yusuf; B. Purwantara; G. Semiadi

    2011-01-01

    In order to improve Timor deer (Cervus timorensis) frozen semen quality, the influence of sugar and glycerol concentration on semen characteristics of sperm was investigated. The semen was collected from five sexually mature Timor deer using an electroejaculator. The semen was evaluated and divided into six equal tubes and diluted with Tris sucrose glycerol 10% (TSG10); Tris sucrose glycerol 12% (TSG12); Tris sucrose glycerol 14% (TSG14); Tris glucose glycerol 10% (TGG10); Tris glucose glyce...

  6. Dimerization effect of sucrose octasulfate on rat FGF1

    International Nuclear Information System (INIS)

    The work describes the sucrose octasulfate-mediated dimerization of rat FGF1 by gel-filtration experiments and crystal structure determination. 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

  7. Magnetic birefringence of iron oxyhydroxide nanoparticles stabilised by sucrose

    International Nuclear Information System (INIS)

    Magnetically induced optical birefringence is used to investigate pharmaceutically important iron-sucrose aqueous suspensions. XRD and TEM measurements of the system of oxyhydroxide particles stabilised by sucrose have shown that this system contains iron oxyhydroxide in the form of 2-5 nm particles. The mineral form of the iron-core is suggested to be akaganeite. Anisotropy of the optical polarizability and magnetic susceptibility of akaganeite nanoparticles are calculated. The permanent dipole moment obtained for the nanoparticles studied was found to be negligible, in agreement with the characteristic superparamagnetic behaviour of the magnetic nanoparticles observed at room temperature. The Neel temperature of these nanoparticles is estimated as below 276 K. The results obtained are discussed against a background of the earlier studies of similar nanoscale systems. - Research highlights: → Polysaccharides iron complex, important in pharmaceutical applications, was studied by magnetic birefringence. → Magnetic and optical properties of the akaganeite core has been obtained. The superparamagnetic behaviour of the core has been confirmed. → The experiment suggests that the Neel temperature of these nanoparticles should be set below 276 K. The results show the importance of the magneto-optical method in recognition of magnetic properties of biologically important substances.

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

    Science.gov (United States)

    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

  9. [14C]sucrose uptake and labeling of starch in developing grains of normal segl barley

    International Nuclear Information System (INIS)

    Previous work showed that the segl mutant of barley (Hordeum vulgare o Betzes) did not differ from normal Betzes in plant growth, photosynthesis, or fertility, but it produced only shrunken seeds regardless of pollen source. To determine whether defects in sucrose uptake or starch synthesis resulted in the shrunken condition, developing grains of Betzes and segl were cultured in [14C]sucrose solutions after slicing transversely to expose the endosperm cavity and free space. In both young grains (before genotypes differed in dry weight) and older grains (17 days after anthesis, when segl grains were smaller than Betzes), sucrose uptake and starch synthesis were similar in both genotypes on a dry weight basis. To determine if sucrose was hydrolyzed during uptake, spikes of Betzes and segl were allowed to take up [fructose-U-14C]sucrose 14 days after anthesis and the radioactivity of endosperm sugars was examined during 3 hours of incubation. Whereas less total radioactivity entered the endosperm and the endosperm cavity (free space) of segl, in both genotypes over 96% of the label of endosperm sugars was in sucrose, and there was no apparent initial or progressive randomization of label among hexose moieties of sucrose as compared to the free space sampled after 1 hour of incubation. The authors conclude that segl endosperms are capable of normal sucrose uptake and starch synthesis and that hydrolysis of sucrose is not required for uptake in either genotype. Evidence suggests abnormal development of grain tissue of maternal origin during growth of segl grains

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

    OpenAIRE

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

    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 was allocated to sucrose and more reinforcements were obtained from that alternative. Allocation of behavior to wheel running decreased, but obtained...

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

    Science.gov (United States)

    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. PMID:23415661

  12. Biological Sensor for Sucrose Availability: Relative Sensitivities of Various Reporter Genes

    OpenAIRE

    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 obse...

  13. Altered sucrose synthase and invertase expression affects the local and systemic sugar metabolism of nematode-infected Arabidopsis thaliana plants

    OpenAIRE

    Cabello, Susana; Lorenz, Cindy; Crespo, Sara; Cabrera, Javier; Ludwig, Roland; Escobar, Carolina; Hofmann, Julia

    2013-01-01

    Sedentary endoparasitic nematodes of plants induce highly specific feeding cells in the root central cylinder. From these, the obligate parasites withdraw all required nutrients. The feeding cells were described as sink tissues in the plant’s circulation system that are supplied with phloem-derived solutes such as sugars. Currently, there are several publications describing mechanisms of sugar import into the feeding cells. However, sugar processing has not been studied so far. Thus, in the p...

  14. Analysis of the myosins encoded in the recently completed Arabidopsis thaliana genome sequence

    Science.gov (United States)

    Reddy, A. S.; Day, I. S.

    2001-01-01

    BACKGROUND: Three types of molecular motors play an important role in the organization, dynamics and transport processes associated with the cytoskeleton. The myosin family of molecular motors move cargo on actin filaments, whereas kinesin and dynein motors move cargo along microtubules. These motors have been highly characterized in non-plant systems and information is becoming available about plant motors. The actin cytoskeleton in plants has been shown to be involved in processes such as transportation, signaling, cell division, cytoplasmic streaming and morphogenesis. The role of myosin in these processes has been established in a few cases but many questions remain to be answered about the number, types and roles of myosins in plants. RESULTS: Using the motor domain of an Arabidopsis myosin we identified 17 myosin sequences in the Arabidopsis genome. Phylogenetic analysis of the Arabidopsis myosins with non-plant and plant myosins revealed that all the Arabidopsis myosins and other plant myosins fall into two groups - class VIII and class XI. These groups contain exclusively plant or algal myosins with no animal or fungal myosins. Exon/intron data suggest that the myosins are highly conserved and that some may be a result of gene duplication. CONCLUSIONS: Plant myosins are unlike myosins from any other organisms except algae. As a percentage of the total gene number, the number of myosins is small overall in Arabidopsis compared with the other sequenced eukaryotic genomes. There are, however, a large number of class XI myosins. The function of each myosin has yet to be determined.

  15. Expression of an "Arabidopsis CAX2" variant in potato tubers increases calcium levels with no accumulation of manganese

    Science.gov (United States)

    Previously, we made a chimeric "Arabidopsis thaliana" vacuolar transporter CAX2B [a variant of N-terminus truncated form of CAX2 (sCAX2) containing the "B" domain from CAX1] that has enhanced calcium (Ca[2+]) substrate specificity and lost the manganese (Mn[2+]) transport capability of sCAX2. Here, ...

  16. Effect of Sucrose Concentration on Sucrose-Dependent Adhesion and Glucosyltransferase Expression of S. mutans in Children with Severe Early-Childhood Caries (S-ECC

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2014-09-01

    Full Text Available Sucrose, extracellular polysaccharide, and glucosyltransferases (GTFs are key factors in sucrose-dependent adhesion and play important roles in the process of severe early-childhood caries (S-ECC. However, whether sucrose concentration regulates gtf expression, extracellular polysaccharide synthesis, and sucrose-dependent adhesion is related to the different genotypes of S. mutans isolated from ECC in children and still needs to be investigated. In this study, 52 strains of S. mutans were isolated from children with S-ECC and caries-free (CF children. Water-insoluble glucan (WIG synthesis was detected by the anthrone method, adhesion capacity by the turbidimetric method, and expression of gtf by RT-PCR in an in vitro model containing 1%–20% sucrose. The genotypes of S. mutans were analyzed by AP-PCR. The results showed that WIG synthesis, adhesion capacity, and gtf expression increased significantly when the sucrose concentration was from 1% to 10%. WIG synthesis and gtfB as well as gtfC expression of the 1% and 5% groups were significantly lower than those of the 10% and 20% groups (p < 0.05. There were no significant differences between the 10% and 20% groups. The fingerprints of S. mutans detected from individuals in the S-ECC group exhibited a significant difference in diversity compared with those from CF individuals (p < 0.05. Further, the expression of gtfB and gtfC in the S-ECC group was significantly different among the 1- to 5-genotype groups (p < 0.05. It can be concluded that sucrose-dependent adhesion might be related to the diversity of genotypes of S. mutans, and the 10% sucrose level can be seen as a “turning point” and essential factor for the prevention of S-ECC.

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

    Science.gov (United States)

    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

  18. Comparison of Oral Iron and IV Iron Sucrose for Treatment of Anemia in Postpartum Indian Women

    Directory of Open Access Journals (Sweden)

    Aggarwal Rohina S, Mishra Vineet V, Panchal Navin A, Patel Nital H, Deshchougule Vrushali V, Jasani Anil F

    2012-01-01

    Full Text Available Objectives: To determine the efficacy of intravenous iron sucrose and oral iron in anaemic postpartum women, presenting at Institute of Kidney Disease and Research Centre. Method: Descriptive case series. The study was carried out in the department of Obstetrics and Gynaecology at Institute of Kidney Disease and Research Centre over a period of six months from 02-02-2010 to 02-08-2010. 50 cases with proven iron deficiency with Hb ?7gm% were included in the study. Total iron deficit was calculated using a standard formula. Target haemoglobin was 12 gm %. Iron sucrose was administered by intravenous infusion. Haemoglobin was repeated 1, 2, 3, and 4 weeks after the last dose of intravenous iron sucrose. Results: On inclusion, the 2 groups were comparable in terms of both anthropometric and biologic data Distribution of cases by economic status showed, 21 patients (42.0% belonged to lower class, 20 patients (40% belonged to middle class and 09 patients (18% were of upper class.Target hemoglobin levels were achieved in 4 weeks time in 20 (80% patients in iron sucrose group as compared to 10 (40% of patients in oral iron group .There was significant improvement in the various hematological parameters in iv sucrose group as compared to patients in oral iron group. There were no significant allergic reactions in IV sucrose group. Conclusion: This study has shown a significant improvement in the iron sucrose group. Iron sucrose is safe and well tolerated.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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)…

  1. A sucrose-rich diet induces mutations in the rat colon

    DEFF Research Database (Denmark)

    Dragsted, L.O.; Daneshvar, B.; Vogel, Ulla Birgitte; Autrup, H.N.; Wallin, H.; Risom, L.; Møller, Per; Molck, A.M.; Hansen, Max; Poulsen, H.E.; Loft, S.

    2002-01-01

    added sucrose to the diet of Big Blue rats, a strain of Fischer rats carrying 40 copies of the lambda-phage on chromosome 4. Dietary sucrose was provided to the rats for 3 weeks at four dose levels including the background level in the purified diet [3.4% (control), 6.9%, 13.8%, or 34.5%] without...

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

    International Nuclear Information System (INIS)

    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 (3H-fructose) 1'fluorosucrose (14C-glucose) were applied at 10 mM (3H/14C=1) to an attached source leaf. After 6 h, sugars from plant parts in the translocation path were separated on HPLC. 14C-1'fluorosucrose was translocated and accumulated in the root at a higher rate than 3H-sucrose due to greater metabolism of 3H-sucrose in the shoot (indicated by the presence of 3H in hexose fractions and loss of asymmetry). In the root 25% of the 3H-sucrose was hydrolyzed to hexoses whereas no 14C 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

  3. Oxytocin Differentially Affects Sucrose Taking and Seeking in Male and Female Rats

    Science.gov (United States)

    Zhou, Luyi; Ghee, Shannon M.; See, Ronald E.; Reichel, Carmela M.

    2015-01-01

    Oxytocin has a modulatory role in natural and drug reward processes. While the role of oxytocin in pair bonding and reproduction has been extensively studied, sex differences in conditioned and unconditioned behavioral responses to oxytocin treatment have not been fully characterized. Here, we determined whether male and female rats would show similar dose response curves in response to acute oxytocin on measures of locomotor activity, sucrose seeking, and sucrose intake. Male and freely cycling female rats received vehicle or oxytocin (0.1, 0.3, 1, 3 mg/kg, IP) injections before behavioral tests designed to assess general motor activity, as well as sucrose self-administration and seeking. Lower doses of oxytocin decreased motor activity in a novel environment in females relative to males. Likewise, lower doses of oxytocin in females decreased responding for sucrose during maintenance of sucrose self-administration and reinstatement to sucrose-conditioned cues. However, sucrose seeking in response to a sucrose prime was only decreased by the highest oxytocin dose in both sexes. In general, oxytocin had similar effects in both sexes. However, females were more sensitive to lower doses of oxytocin than males. These findings are consistent with the notion that oxytocin regulates many of the same behaviors in males and females, but that the effects are typically more profound in females. Therapeutic use of oxytocin should include sex as a factor in determining dose regimens. PMID:25647756

  4. Comparative Proteomic Analysis of Arabidopsis Mature Pollen and Germinated Pollen

    Institute of Scientific and Technical Information of China (English)

    Junjie Zou; Lianfen Song; Wenzheng Zhang; Yi Wang; Songlin Ruan; Wei-Hua Wu

    2009-01-01

    Proteomic analysis was applied to generating the map of Arabidopsis mature pollen proteins and analyzing the differentially expressed proteins that are potentially involved in the regulation of Arabidopsis pollen germination. By applying 2-D electrophoresis and silver staining, we resolved 499 and 494 protein spots from protein samples extracted from pollen grains and pollen tubes, respectively. Using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry method, we identified 189 distinct proteins from 213 protein spots expressed in mature pollen or pollen tubes, and 75 new identified proteins that had not been reported before in research into the Arabidopsis pollen proteome. Comparative analysis revealed that 40 protein spots exhibit reproducible significant changes between mature pollen and pollen tubes. And 21 proteins from 17 downregulated and six upregulated protein spots were identified. Functional category analysis indicated that these differentially expressed proteins mainly involved in signaling, cellular structure, transport, defense/stress responses, transcription, metabolism, and energy production. The patterns of changes at protein level suggested the important roles for energy metabolism-related proteins in pollen tube growth, accompanied by the activation of the stress response pathway and modifications to the cell wall.

  5. HEXOKINASE 1 is required for glucose-induced repression of bZIP63, At5g22920 and BT2 in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sabine eKunz

    2015-07-01

    Full Text Available Simple sugars, like glucose and sucrose, act as signals to modulate the expression of hundreds of genes in plants. Frequently, however, it remains unclear whether this regulation is induced by the sugars themselves or by their derivatives generated in the course of carbohydrate (CH metabolism. In the present study, we tested the relevance of different CH metabolism and allocation pathways affecting expression patterns of five selected sugar-responsive genes (bZIP63, At5g22920, BT2, MGD2 and TPS9 in Arabidopsis thaliana. In general, the expression followed diurnal changes in the overall sugar availability. However, under steady growth conditions, this response was hardly impaired in the mutants for CH metabolizing/ transporting proteins (adg1, sex1, sus1-4, sus5/6 and tpt2, including also hexokinase1 (HXK1 loss- and gain-of-function plants - gin2.1 and oe3.2, respectively. In addition, transgenic plants carrying pbZIP63::GUS showed no changes in reporter-gene-expression when grown on sugar under steady-state conditions. In contrast, short-term treatments of agar-grown seedlings with 1% glucose or sucrose induced pbZIP63::GUS repression, which became even more apparent in seedlings grown in liquid media. Subsequent analyses of liquid-grown gin2.1 and oe3.2 seedlings revealed that glucose-dependent regulation of the five selected genes was not affected in gin2.1, whereas it was enhanced in oe3.2 plants for bZIP63, At5g22920 and BT2. The sugar treatments had no effect on ATP/ADP ratio, suggesting that changes in gene expression were not linked to cellular energy status. Overall, the data suggest that HXK1 does not act as glucose sensor controlling bZIP63, At5g22920 and BT2 expression, but it is nevertheless required for production of a downstream metabolic signal regulating their expression.

  6. Pronounced phenotypic changes in transgenic tobacco plants overexpressing sucrose synthase may reveal a novel sugar signaling pathway

    Directory of Open Access Journals (Sweden)

    Quynh Anh eNguyen

    2016-01-01

    Full Text Available 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-hour 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.

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

    International Nuclear Information System (INIS)

    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.

  8. [14C]-Sucrose uptake by guard cell protoplasts of pisum sativum, argenteum mutant

    International Nuclear Information System (INIS)

    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 [14C]-sucrose. Uptake rates were corrected after measurement of 14C-sorbitol and 3H2O spaces. Sucrose uptake followed biphasic kinetics, with a high-affinity component below 1 mM external sucrose (apparent Km 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. EPR response of sucrose and microcrystalline cellulose to measure high doses of gamma radiation

    International Nuclear Information System (INIS)

    Solid dosimeters of sucrose and microcrystalline cellulose (Avicel Ph-102) were prepared, following the same process, in order to compare their EPR response against that of the l-alanine dosimeters considered as reference. All lots of dosimeters were irradiated with gamma radiation in Gamma beam irradiator with 8 kGy/h of the Nuclear Sciences Institute of UNAM. Doses ranged from 1 to 10 kGy respectively. We found that both the response of sucrose as microcrystalline cellulose were linear; however, the response intensity was, on average, twenty times more for sucrose. Comparing this against the EPR response of l-alanine in the range of doses, it was found that the response to sucrose is a third part; and microcrystalline cellulose is a sixtieth, approximately. The results agree with those found in the literature for sucrose, leaving open the possibility of investigating other dosage ranges for cellulose. (Author)

  10. Characterization of a mutant from Lactobacillus amylovorus JCM 1126(T) with improved utilization of sucrose.

    Science.gov (United States)

    Oda, Y; Ito, M

    2000-12-01

    A strain YF43, which can grow on sucrose as rapidly as glucose, was isolated by mutation from Lactobacillus amylovorus JCM 1126, the type strain defective in sucrose utilization. Exogenous sucrose stimulated the production of invertase by strains YF43 and JCM 1126 simultaneously. In a medium containing fructooligosaccharide as the sole carbon source, the cells of strain YF43 showed high invertase activity in spite of poor growth. The two invertases produced in the cells grown on sucrose and fructooligosaccharide were an identical beta-fructofuranosidase, as judged from properties of partially purified enzymes. These observations indicated that strain YF43 is a mutant improved for permeation of sucrose and not derepressed for the synthesis of invertase. PMID:11080387

  11. Arabidopsis thaliana—Aphid Interaction

    OpenAIRE

    Louis, Joe; Singh, Vijay,; Shah, Jyoti

    2012-01-01

    Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide impor...

  12. Selenium Speciation in Arabidopsis Thaliana

    OpenAIRE

    Wang, Xiaoou

    2011-01-01

    Selenium has been proved as an essential micronutrient and is beneficial to animals and humans. It is a structural component of the important antioxidant enzyme, glutathione peroxidase, which catalyzes reactions to detoxify reactive oxygen species. However, the essentiality of Se in plants remains controversial and the protective role of Se in plants has rarely been investigated. In this study, Arabidopsis thaliana was grown in controlled environments having selenate or selenite enriched medi...

  13. Stem cell organization in Arabidopsis

    OpenAIRE

    Wendrich, J.R.

    2016-01-01

    Growth of plant tissues and organs depends on continuous production of new cells, by niches of stem cells. Stem cells typically divide to give rise to one differentiating daughter and one non-differentiating daughter. This constant process of self-renewal ensures that the niches of stem cells or meristems stay active throughout plant-life. Specification of stem cells occurs very early during development of the emrbyo and they are maintained during later stages. The Arabidopsis embryo is a hig...

  14. Identification of actively filling sucrose sinks. [Solanum tuberosum; Phaseolus lunatus; Manihot esculenta; Liquidambar styraciflua L. ; Carya illinoinensis

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Shijean S.; Xu, Dianpeng; Black C.C. (Univ. of Georgia, Athens (USA))

    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.

  15. The F130S point mutation in the Arabidopsis high-affinity K+ transporter AtHAK5 increases K+ over Na+ and Cs+ selectivity and confers Na+ and Cs+ tolerance to yeast under heterologous expression

    Directory of Open Access Journals (Sweden)

    Fernando eAleman

    2014-09-01

    Full Text Available Potassium (K+ is an essential macronutrient required for plant growth, development and high yield production of crops. Members of group I of the KT/HAK/KUP family of transporters, such as HAK5, are key components for K+ acquisition by plant roots at low external K+ concentrations. Certain abiotic stress conditions such as salinity or Cs+-polluted soils may jeopardize plant K+ nutrition because HAK5-mediated K+ transport is inhibited by Na+ and Cs+. Here, by screening in yeast a randomly-mutated collection of AtHAK5 transporters, a new mutation in AtHAK5 sequence is identified that greatly increases Na+ tolerance. The single point mutation F130S, affecting an amino acid residue conserved in HAK5 transporters from several species, confers high salt tolerance, as well as Cs+ tolerance. This mutation increases more than 100-fold the affinity of AtHAK5 for K+ and reduces the Ki values for Na+ and Cs+, suggesting that the F130 residue may contribute to the structure of the pore region involved in K+ binding. In addition, this mutation increases the Vmax for K+. All this changes occur without increasing the amount of the AtHAK5 protein in yeast and support the idea that this residue is contributing to shape the selectivity filter of the AtHAK5 transporter.

  16. Use of the Biphasic (13)C-Sucrose/Glucose Breath Test to Assess Sucrose Maldigestion in Adults with Functional Bowel Disorders.

    Science.gov (United States)

    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

  17. Strigolactone acts downstream of auxin to regulate bud outgrowth in pea and Arabidopsis.

    Science.gov (United States)

    Brewer, Philip B; Dun, Elizabeth A; Ferguson, Brett J; Rameau, Catherine; Beveridge, Christine A

    2009-05-01

    During the last century, two key hypotheses have been proposed to explain apical dominance in plants: auxin promotes the production of a second messenger that moves up into buds to repress their outgrowth, and auxin saturation in the stem inhibits auxin transport from buds, thereby inhibiting bud outgrowth. The recent discovery of strigolactone as the novel shoot-branching inhibitor allowed us to test its mode of action in relation to these hypotheses. We found that exogenously applied strigolactone inhibited bud outgrowth in pea (Pisum sativum) even when auxin was depleted after decapitation. We also found that strigolactone application reduced branching in Arabidopsis (Arabidopsis thaliana) auxin response mutants, suggesting that auxin may act through strigolactones to facilitate apical dominance. Moreover, strigolactone application to tiny buds of mutant or decapitated pea plants rapidly stopped outgrowth, in contrast to applying N-1-naphthylphthalamic acid (NPA), an auxin transport inhibitor, which significantly slowed growth only after several days. Whereas strigolactone or NPA applied to growing buds reduced bud length, only NPA blocked auxin transport in the bud. Wild-type and strigolactone biosynthesis mutant pea and Arabidopsis shoots were capable of instantly transporting additional amounts of auxin in excess of endogenous levels, contrary to predictions of auxin transport models. These data suggest that strigolactone does not act primarily by affecting auxin transport from buds. Rather, the primary repressor of bud outgrowth appears to be the auxin-dependent production of strigolactones. PMID:19321710

  18. A crossover trial of high and low sucrose-carbohydrate diets in type II diabetics with hypertriglyceridemia.

    Science.gov (United States)

    Emanuele, M A; Abraira, C; Jellish, W S; DeBartolo, M

    1986-01-01

    Earlier work shows that hyperlipemic type II diabetics tolerate wide ranges of sucrose and carbohydrate intake without effects on glycemic control, but a rise of fasting serum triglycerides sometimes occurs. To address further the issue of individual susceptibility to carbohydrate, the current study was designed to use each patient as his own control when given diets widely varying in sucrose content. After a stabilization period in the hospital on a normal sucrose content diet, each subject was given either a very low sucrose (less than 3 gm/day)-low carbohydrate (38 +/- 2%) diet or a high sucrose (220 gm)-high carbohydrate (63 +/- 3%) diet for 4 weeks. On a separate admission the opposite diet was assessed, again after an initial normal sucrose content diet. No consistent differences occurred in serum glucose levels or in 24-hr urinary glycosuria. High sucrose-carbohydrate intake raised fasting hypertriglyceridemia after 2 weeks but less thereafter. Severe sucrose-carbohydrate restriction did not significantly decrease fasting serum triglycerides; postprandial triglycerides changed in a trend opposite to fasting levels. No differences occurred in fasting serum insulin or serum cholesterol levels, but postprandial insulin levels were higher in high sucrose-carbohydrate diets. A diet with low sucrose and low total carbohydrate appears to offer no improvement in glycemic control over at least 70-fold higher dietary sucrose levels. However, high sucrose and carbohydrate diets increase fasting triglyceride levels in hypertriglyceridemic type II diabetics. PMID:3537075

  19. An International Bioinformatics Infrastructure to Underpin the Arabidopsis Community

    Science.gov (United States)

    The future bioinformatics needs of the Arabidopsis community as well as those of other scientific communities that depend on Arabidopsis resources were discussed at a pair of recent meetings held by the Multinational Arabidopsis Steering Committee (MASC) and the North American Arabidopsis Steering C...

  20. Arabidopsis CDS blastp result: AK106750 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK106750 002-115-C09 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  1. Arabidopsis CDS blastp result: AK104851 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104851 001-043-A10 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  2. Arabidopsis CDS blastp result: AK100909 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100909 J023132G24 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylul ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  3. Arabidopsis CDS blastp result: AK058950 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058950 001-020-A07 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  4. Arabidopsis CDS blastp result: AK059821 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK059821 006-205-D11 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylu ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  5. Arabidopsis CDS blastp result: AK064944 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK064944 J013000P14 At4g15560.1 1-deoxy-D-xylulose 5-phosphate synthase, putative / 1-deoxyxylul ... phate synthase, putative / DXP-synthase, putative (DEF ) (CLA1) identical to SP|Q38854 Probable 1-deoxy-D- ... (DXPS). [Mouse-ear cress] {Arabidopsis thaliana}, DEF ... (def icient in photosynthesis) protein [Arabidopsis ...

  6. Arabidopsis CDS blastp result: AK068400 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK068400 J013151M04 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  7. Arabidopsis CDS blastp result: AK066013 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066013 J013047I12 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  8. Arabidopsis CDS blastp result: AK100241 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100241 J023054P13 At3g45810.1 ferric reductase-like transmembrane component family protein sim ... ilar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  9. Arabidopsis CDS blastp result: AK318553 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318553 J075145A22 At3g45810.1 68416.m04958 ferric reductase-like transmembrane component famil ... y protein similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ... EMBL:AF055357 [gi:3242789], similar to respiratory burst ... oxidase protein D RbohD from Arabidopsis thaliana, ...

  10. Using "Arabidopsis" Genetic Sequences to Teach Bioinformatics

    Science.gov (United States)

    Zhang, Xiaorong

    2009-01-01

    This article describes a new approach to teaching bioinformatics using "Arabidopsis" genetic sequences. Several open-ended and inquiry-based laboratory exercises have been designed to help students grasp key concepts and gain practical skills in bioinformatics, using "Arabidopsis" leucine-rich repeat receptor-like kinase (LRR RLK) genetic…

  11. Enamel and dentine demineralization by a combination of starch and sucrose in a biofilm - caries model.

    Science.gov (United States)

    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

  12. Differential motivational profiles following adolescent sucrose access in male and female rats.

    Science.gov (United States)

    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 2h each day for 28days 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

  13. The Measurement of Sucrose Content of Sugar Cane Using Ultrasonic Waves

    Directory of Open Access Journals (Sweden)

    Amoranto Trisnobudi, Tjia Liong Hoei, Enung Rosihan Nugraha

    2001-04-01

    Full Text Available The measurement of sucrose content of sugar cane is usually carried out by using polarimeter and Brix Wager scale. These two apparatus are operated manually so that the accuracy of the measurement results is depended on the operator skill. To overcome this problem we have developed an alternative method that can measure the sucrose content more quickly and accurately than the conventional methods. This new method was carried out by using ultrasonic waves whose velocity depends on the sucrose content. Firstly, the electronic apparatus used was calibrated with 37 samples of sugar cane with various sucrose content from 4.46 % to 7.29 %. The result of this calibration was an empirical equation between the ultrasonic wave velocity V and the sucrose content R, i.e. R = 2.65 V2 - 11,95 V + 17,65 where R in % and V in km/s. Then this equation was stored as database in a computer program that will be used to calculate the sucrose content. Finally, this sucrose content measurement system was tested by using 30 samples of sugar cane. The maximum error of the measurement result was 6.4 %.

  14. Analysis of Protein Oligomeric Species by Sucrose Gradients.

    Science.gov (United States)

    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

  15. Effects of Vacuum Impregnation with Sucrose Solution on Mango Tissue.

    Science.gov (United States)

    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

  16. Rationalization of Sucrose Solution Using During the Fruit Osmotic Dehydration

    Directory of Open Access Journals (Sweden)

    Mirko Babić

    2009-12-01

    Full Text Available The model of sustainable energy production of dried fruit conducted by using combined technology – the model that has been developed at the Faculty of Agriculture in Novi Sad – includes osmotic dehydration of fruit in sucrose solution. During the process of dehydration the moisture content of the solution is increased due to mass transfer of moisture from fruit. This article examines different models of recycling and concentrating of the solution. Thus, the model for concentrating of the solution has been chosen according to this analysis, and it has been applied within its own technology. Evaporators of the low temperature solution have been used and they are based on the solar energy source. Two types of devices have been made on the basis of the heating process of evaporating. One type is filled with the stainless steel shavings, while the other type is based on the fillings by plates. The paper presents the evaluation model of the benefits of this concentrating manner as well as the evaluation criterion of the evaporators’ fillings types. The energy support used here was an original solar air heater of semi-concentrated type.

  17. HPA axis dampening by limited sucrose intake: reward frequency vs. caloric consumption

    OpenAIRE

    Ulrich-Lai, Yvonne M.; Ostrander, Michelle M; Herman, James P.

    2010-01-01

    Individuals often cope with stress by consuming calorically-dense, highly-palatable “comfort” foods. The present work explores the stress-relieving properties of palatable foods in a rat model of limited sucrose intake. In this model, adult male rats with free access to chow and water are given additional access to a small amount of sucrose drink (or water as a control). A history of such limited sucrose intake reduces the collective (HPA axis, sympathetic, and behavioral-anxiety) stress resp...

  18. Pollen Morphology and Sucrose Giving on Stigma Relation with Incopability of Sweetpotato [Ipomoea Batatas (L.) L.

    OpenAIRE

    Febri Adi Susanto; Eko Sri Sulasmi; St. A. Rahayuningsih

    2013-01-01

    This research aimed to increase the success rate of self-pollination in sweetpotato through sucrose treatment on stigma and pollen nuclei check. Various concentration of sucrose was applied on the stigma. Prior to the crosses, the stigma was excised and lubricated with sucrose. Pedicel was lubricated with 100 ppm of 2,4 D in lanolin. The result showed that the stigma of both varieties was longer than the anther. Papua Solosa showed 94,7% anther dehiscence and 70, 25% pollen viability; whereas...

  19. COMPARATIVE STUDY BETWEEN INTRAVENOUS IRON SUCROSE AND ORAL IRON FOR TREATMENT OF POST PARTUM ANEMIA

    Directory of Open Access Journals (Sweden)

    Samta

    2014-03-01

    Full Text Available AIMS & OBJECTIVES: The aim of study was to compare the efficacy, safety and compliance of intravenous iron sucrose complex with oral Iron therapy in treatment of postpartum anemia. MATERIAL AND METHODS: 60 postpartum women who had delivered within 24 -48 hours and having hemoglobin 0.05. Intravenous iron sucrose did not result in any serious adverse reactions. CONCLUSION: Intravenous iron sucrose is more effective, rapid and safe in increasing hemoglobin level in women with postpartum anemia in comparison with oral iron therapy. It also replenishes iron stores more rapidly without any serious adverse effects.

  20. A sucrose-rich diet induces mutations in the rat colon

    DEFF Research Database (Denmark)

    Dragsted, L.O.; Daneshvar, B.; Vogel, Ulla Birgitte;

    2002-01-01

    cell turnover as determined by the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphate nick end labeling assay and proliferating cell nuclear antigen. An increase in liver ascorbate was also observed, whereas oxidative damage was not observed in proteins or lipids in...... systems. We also conclude that an oxidative mechanism for this effect of sucrose is unlikely. This is the first demonstration of a genotoxic action of increased dietary sucrose in vivo. Both sucrose intake and colon cancer rates are high in the Western world, and our present results call for an...

  1. Modifying post-harvest sucrose loss in sugar beet : Assessment of transgenic approaches

    OpenAIRE

    Jansen, Andrea, 1983-

    2009-01-01

    Sugar beet (Beta vulgaris L.) is one of the economically most important plants storing high levels of sucrose. Sucrose is accumulated in the taproot inside the vacuoles of parenchyma cells, with up to nearly 20 % of fresh weight. Harvesting of sugar beet includes wounding of taproots, leading to induction of invertases and consequently to sucrose loss. In the present study, the interaction of the sugar beet invertase inhibitor BvC/VIF (Beta vulgaris cell wall and/or vacuolar inhibitor of ß-f...

  2. Application of isotope dilution to the determination of sucrose in sugar beets of various quality

    International Nuclear Information System (INIS)

    The methods of the direct isotopic dilution and double carrierisotopic dilution to determine the sucrose content in sugar beets of different technological quality have been elaborated. The elaborated methods have been checked upon the model solutions. The comparative determinations of sucrose content in industry processed sugar beets has been performed. Based upon the obtained results it has been ascertained, that polarimetric determinations of sucrose content in healthy and fresh beets agree with results of the isotopic determinations. In case of decayed and putrefayed beets polarimetric determinations strays in plus and in minus from isotope results. (author)

  3. Sucrose/bovine serum albumin mediated biomimetic crystallization of calcium carbonate

    Indian Academy of Sciences (India)

    Cheng-Li Yao; Wang-Hua Xu; Ai-Min Ding; Jin-Mao Zhu

    2009-01-01

    To understand the role of the sucrose/bovine serum albumin system in the biomineralization process, we have tested the influence of different concentration of the sucrose/bovine serum albumin (BSA) on calcium carbonate (CaCO3) precipitation. The CaCO3 crystals were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrograph (FT-IR) and powder X-ray diffractometry (XRD). The possible formation mechanism of CaCO3 in the sucrose/bovine serum albumin system was discussed.

  4. Biological sensor for sucrose availability: relative sensitivities of various reporter genes.

    Science.gov (United States)

    Miller, W G; Brandl, M T; Quiñones, B; Lindow, S E

    2001-03-01

    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 microM 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 micro

  5. Detecting autophagy in Arabidopsis roots by membrane-permeable cysteine protease inhibitor E-64d and endocytosis tracer FM4–64

    OpenAIRE

    Oh-ye, Yuumi; Inoue, Yuko; Moriyasu, Yuji

    2011-01-01

    Autophagy is the process by which cells degrade their own components in lysosomes or vacuoles. Autophagy in tobacco BY-2 cells cultured in sucrose-free medium takes place in formed, autolysosomes in the presence of a cysteine protease inhibitor. The autolysosomes in BY-2 cells are located in the endocytotic pathway and thus can be stained with fluorescent endocytosis marker FM4–64. In the present study, in order to detect autophagy in the root cells of Arabidopsis, we incubated root tips from...

  6. Transport and phosphorylation of disaccharides by the ruminal bacterium Streptococcus bovis

    International Nuclear Information System (INIS)

    Toluene-treated cells of Streptococcus bovis JB1 phosphorylated cellobiose, glucose, maltose, and sucrose by the phosphoenolpyruvate-dependent phosphotransferase system. Glucose phosphorylation was constitutive, while all three disaccharide systems were inducible. Competition experiments, indicated that separate phosphotransferases systems existed for glucose, maltose, and sucrose. [14C]maltose transport was inhibited by excess glucose and to a lesser extent by sucrose. [14C]glucose and [14C]sucrose transports were not inhibited by an excess of maltose. Since [14C]maltose phosphorylation in triethanolamine buffer was increased 160-fold as the concentration of P/sub i/ was increased from 0 to 100 mM, a maltose phosphorylase was present, and this activity was inducible. Maltose was also hydrolyzed by an inducible maltase. Glucose 1-phosphate arising from the maltose phosphorylase was metabolized by a constitutive phosphoglucomutase that was specific for α-glucose 1-phosphate. Only sucrose-grown cells possessed sucrose hydrolase activity, and this activity was much lower than the sucrose phosphotransferase system and sucrose-phosphate hydrolase activities

  7. Functional analysis of the rice vacuolar zinc transporter OsMTP1

    OpenAIRE

    Menguer, Paloma K.; Farthing, Emily; Peaston, Kerry A.; Ricachenevsky, Felipe Klein; Fett, Janette Palma; Williams, Lorraine E.

    2013-01-01

    Heavy metal homeostasis is maintained in plant cells by specialized transporters which compartmentalize or efflux metal ions, maintaining cytosolic concentrations within a narrow range. OsMTP1 is a member of the cation diffusion facilitator (CDF)/metal tolerance protein (MTP) family of metal cation transporters in Oryza sativa, which is closely related to Arabidopsis thaliana MTP1. Functional complementation of the Arabidopsis T-DNA insertion mutant mtp1-1 demonstrates that OsMTP1 transports ...

  8. Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana.

    Science.gov (United States)

    Harris, Sue-Re; Henbest, Kevin B; Maeda, Kiminori; Pannell, John R; Timmel, Christiane R; Hore, P J; Okamoto, Haruko

    2009-12-01

    The scientific literature describing the effects of weak magnetic fields on living systems contains a plethora of contradictory reports, few successful independent replication studies and a dearth of plausible biophysical interaction mechanisms. Most such investigations have been unsystematic, devoid of testable theoretical predictions and, ultimately, unconvincing. A recent study, of magnetic responses in the model plant Arabidopsis thaliana, however, stands out; it has a clear hypothesis-that seedling growth is magnetically sensitive as a result of photoinduced radical-pair reactions in cryptochrome photoreceptors-tested by measuring several cryptochrome-dependent responses, all of which proved to be enhanced in a magnetic field of intensity 500 muT. The potential importance of this study in the debate on putative effects of extremely low-frequency electromagnetic fields on human health prompted us to subject it to the 'gold standard' of independent replication. With experimental conditions chosen to match those of the original study, we have measured hypocotyl lengths and anthocyanin accumulation for Arabidopsis seedlings grown in a 500 microT magnetic field, with simultaneous control experiments at 50 microT. Additionally, we have determined hypocotyl lengths of plants grown in 50 microT, 1 mT and approximately 100 mT magnetic fields (with zero-field controls), measured gene (CHS, HY5 and GST) expression levels, investigated blue-light intensity effects and explored the influence of sucrose in the growth medium. In no case were consistent, statistically significant magnetic field responses detected. PMID:19324677

  9. Sucrose in Cyanobacteria: From a Salt-Response Molecule to Play a Key Role in Nitrogen Fixation

    Directory of Open Access Journals (Sweden)

    María A. Kolman

    2015-01-01

    Full Text Available 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.

  10. Diverse Exopolysaccharide Producing Bacteria Isolated from Milled Sugarcane: Implications for Cane Spoilage and Sucrose Yield.

    Directory of Open Access Journals (Sweden)

    Stanton Hector

    Full Text Available 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.

  11. Starch and sucrose synthesis in Phaseolus vulgaris as affected by light, CO2, and abscisic acid

    International Nuclear Information System (INIS)

    Phaseolus vulgaris L. leaves were subjected to various light, CO2, and O2 levels and abscisic acid, then given a 10 minute pulse of 14CO2 followed by a 5 minute chase with unlabeled CO2. After the chase period, very little label remained in the ionic fractions except at low CO2 partial pressure. Most label was found in the neutral, alcohol soluble fraction or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate. Starch formation increased linearly with assimilation rate, but did not occur if the assimilation rate was below 4 micromoles per square meter per second. Neither abscisic acid, nor high CO2 in combination with low O2 caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO2 assimilation, with sucrose the preferred product at very low assimilation rates

  12. Microplate assay for rapid determination of sucrose, glucose, fructose and raffinose

    Science.gov (United States)

    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...

  13. Large deformation properties of short doughs: Effect of sucrose in relation to mixing time

    NARCIS (Netherlands)

    Baltsavias, A.; Jurgens, A.; Vliet, T. van

    1999-01-01

    Large deformation rheological properties of short doughs of various composition prepared under various mixing times were determined in uniaxial compression. Sucrose-syrup doughs exhibited prominent yielding and flow behaviour. Their apparent biaxial extensional viscosity decreased with increasing su

  14. 78 FR 66743 - Draft Guidance for Industry on Bioequivalence Recommendations for Iron Sucrose; Availability

    Science.gov (United States)

    2013-11-06

    ... the Federal Register of June 11, 2010 (75 FR 33311), FDA announced the availability of a guidance for... HUMAN SERVICES Food and Drug Administration Draft Guidance for Industry on Bioequivalence... entitled ``Bioequivalence Recommendations for Iron Sucrose.'' The recommendations provide specific...

  15. 77 FR 18827 - Draft Guidance for Industry on Bioequivalence Recommendations for Iron Sucrose Injection...

    Science.gov (United States)

    2012-03-28

    ... Federal Register of June 11, 2010 (75 FR 33311), FDA announced the availability of a guidance for industry... HUMAN SERVICES Food and Drug Administration Draft Guidance for Industry on Bioequivalence... industry entitled ``Bioequivalence Recommendations for Iron Sucrose.'' The recommendations provide...

  16. ESR investigation of L-α-alanine and sucrose radicals produced by heavy-ion irradiation

    International Nuclear Information System (INIS)

    We investigated sucrose and L-α-alanine radicals produced by heavy ion irradiation with various LETs (linear energy transfer). The impact of the heavy ions on the samples produced stable free radicals, which were analyzed by ESR (electron spin resonance). The obtained spectral patterns were the same as those for carbon (C), neon (Ne), and silicon (Si) ion irradiations. The absorbed dose dependences for the irradiated sucrose and alanine samples were examined. The ESR response has a linear relation with the absorbed dose for both compounds. In addition, the total spin concentration obtained by heavy-ion irradiation correlated logarithmically with the LET. Let Qualitative ESR analyses showed that the production of sucrose and alanine radical depended on both different particle irradiation and the LET under the same dose. Thus, the present ESR results imply that sucrose together with L-α-alanine can be used to investigate radical production processes induced by ionizing particles. (author)

  17. Minimization of sucrose losses in sugar industry by pH and temperature optimization

    International Nuclear Information System (INIS)

    Invert sugar has several disadvantage properties that play an important role in many food applications. It has a high affinity for water and is the cause of making products retain moisture. Invert sugar also affects the carmelization process, producing a browning effect. In this study, the possibility of minimization of sucrose inversion during the industrial production of sugar cane was investigated by the variation of the important parameters, i.e. temperature and pH of sugar cane juice for each of samples. The amounts of sucrose and reducing sugar alerting during the sucrose inversion process were determined by the values of % Pol and % reducing sugar (% RS), respectively. Starting with the study of temperature and pH effects of the sucrose solution with the concentration of 16 Brix, used as a sample model, it was found that no change in amounts of reducing sugar and sucrose was observed at room temperature (34 degree Celsius) in the pH range of 5-11. At pH 3, the amounts of reducing sugar increased and the amount of sucrose decreased as the time increased. These indicated that the process of sucrose inversion should better occur in more acidic solutions. Compared to the room temperature, it was found that the increment of temperature led to enhance the process of sucrose inversion. This was depicted by higher values of % RS and lower value of % Pol as the temperatures were elevated. The experiments were also done with real sugar cane juice, i.e. first, last, and mixed juice. The tendency of changes of the amounts of reducing sugar and sucrose in sugar cane samples by varying temperature and pH were found to resemble to those for the sample model. The increment of temperatures have also affected on a reduction of amounts of sucrose in each sugar cane juice. In addition, it could be concluded that the acidity of the solution affects sucrose easier to be broken down to glucose and fructose molecules. (author)

  18. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry

    International Nuclear Information System (INIS)

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (Cp) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the Cp values are now reported for the wide 5–600 K range. The experimental Cp of solid sucrose at 5–300 K was used to calculate the vibrational, solid Cp based on the vibrational molecular motions. The calculated solid and liquid Cp together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (Tm) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium Tm and heat of fusion of crystalline sucrose were estimated at zero heating rate as Tom = 424.4 K and ΔHof = 32 kJ/mol, respectively. The glass transition temperature (Tg) of amorphous sucrose was at 331 K with a change in Cp of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that Tm was 483 K and Tg was 364 K. Superheating effects were observed during the melting with

  19. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Magoń, A. [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland); Wurm, A.; Schick, C. [Department of Physics, University of Rostock, 18057 Rostock (Germany); Pangloli, Ph.; Zivanovic, S. [Department of Food Science and Technology, University of Tennessee, Knoxville, TN 37996 (United States); Skotnicki, M. [Department of Pharmaceutical Technology, Poznan University of Medical Sciences, 60-780 Poznań (Poland); Pyda, M., E-mail: mpyda@utk.edu [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland)

    2014-08-10

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (C{sub p}) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the C{sub p} values are now reported for the wide 5–600 K range. The experimental C{sub p} of solid sucrose at 5–300 K was used to calculate the vibrational, solid C{sub p} based on the vibrational molecular motions. The calculated solid and liquid C{sub p} together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (T{sub m}) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium T{sub m} and heat of fusion of crystalline sucrose were estimated at zero heating rate as T{sup o}{sub m} = 424.4 K and ΔH{sup o}{sub f} = 32 kJ/mol, respectively. The glass transition temperature (T{sub g}) of amorphous sucrose was at 331 K with a change in C{sub p} of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that T{sub m} was

  20. Comparison and validation of two analytical methods for measurement of urinary sucrose and fructose excretion

    OpenAIRE

    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 fr...

  1. Spontaneous switching of the sucrose-promoted colony phenotype in Streptococcus sanguis.

    OpenAIRE

    Tardif, G; Sulavik, M C; Jones, G W; Clewell, D B

    1989-01-01

    Streptococcus sanguis on media containing 3% sucrose gives rise to characteristic hard cohesive colonies (designated Spp+). Populations of Spp+ bacteria (strain Challis) on sucrose media switch to a soft noncohesive phenotype (designated Spp-) at a frequency of 10(-4) to 10(-3). Spp- bacteria switch back to Spp+ bacteria at a similar frequency. Successive rounds of Spp variation were observed. The Spp phenotypic switch was associated with changes in extracellular glucosyltransferase activity.

  2. Sucrose exposure in early life alters adult motivation and weight gain.

    Directory of Open Access Journals (Sweden)

    Cristianne R M Frazier

    Full Text Available The cause of the current increase in obesity in westernized nations is poorly understood but is frequently attributed to a 'thrifty genotype,' an evolutionary predisposition to store calories in times of plenty to protect against future scarcity. In modern, industrialized environments that provide a ready, uninterrupted supply of energy-rich foods at low cost, this genetic predisposition is hypothesized to lead to obesity. Children are also exposed to this 'obesogenic' environment; however, whether such early dietary experience has developmental effects and contributes to adult vulnerability to obesity is unknown. Using mice, we tested the hypothesis that dietary experience during childhood and adolescence affects adult obesity risk. We gave mice unlimited or no access to sucrose for a short period post-weaning and measured sucrose-seeking, food consumption, and weight gain in adulthood. Unlimited access to sucrose early in life reduced sucrose-seeking when work was required to obtain it. When high-sugar/high-fat dietary options were made freely-available, however, the sucrose-exposed mice gained more weight than mice without early sucrose exposure. These results suggest that early, unlimited exposure to sucrose reduces motivation to acquire sucrose but promotes weight gain in adulthood when the cost of acquiring palatable, energy dense foods is low. This study demonstrates that early post-weaning experience can modify the expression of a 'thrifty genotype' and alter an adult animal's response to its environment, a finding consistent with evidence of pre- and peri-natal programming of adult obesity risk by maternal nutritional status. Our findings suggest the window for developmental effects of diet may extend into childhood, an observation with potentially important implications for both research and public policy in addressing the rising incidence of obesity.

  3. Dosakaya Juice Assuages Development of Sucrose Induced Impaired Glucose Tolerance and Imbalance in Antioxidant Defense

    OpenAIRE

    Kumar, Dommati Anand; Pisupati S.R Sweeya; 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 < 0.00...

  4. Optimal Control for Industrial Sucrose Crystallization with Action Dependent Heuristic Dynamic Programming

    OpenAIRE

    Xiaofeng Lin; Heng Zhang; Li Wei; Huixia Liu

    2009-01-01

    This paper applies a neural-network-based approximate dynamic programming (ADP) method, namely, the action dependent heuristic dynamic programming (ADHDP), to an industrial sucrose crystallization optimal control problem. The industrial sucrose crystallization is a nonlinear and slow time-varying process. It is quite difficult to establish a precise mechanism model of the crystallization, because of complex internal mechanism and interacting variables. We developed a neural network model of t...

  5. Role of plaque in the clearance of salivary sucrose and its influence on salivary ph

    OpenAIRE

    Kumar, A; R Hedge; U Dixit

    2011-01-01

    Background: The prevalence of dental caries in children, in India, is higher than many of the industrialized countries. The sugar most commonly associated with dental caries is sucrose, as the microorganisms in the dental plaque have the ability to convert this dietary constituent into various organic acids. Aims and Objectives: This study was conducted to study the effect of the presence of plaque on the salivary clearance of sucrose and to study the effect of the presence of plaque on saliv...

  6. Sugars, sucrose and colorectal cancer risk: the Fukuoka colorectal cancer study

    OpenAIRE

    Wang, Zhenjie; Uchida, Kazuhiro; Ohnaka, Keizo; Morita, Makiko; Toyomura, Kengo; Kono, Suminori; Ueki, Takashi; Tanaka, Masao; Kakeji, Yoshihiro; Maehara, Yoshihiko; Okamura, Takeshi; Ikejiri, Koji; Futami, Kitaroh; Maekawa, Takafumi; Yasunami, Yohichi

    2014-01-01

    Objective A diet high in sugars may promote colorectal carcinogenesis, but it remains uncertain whether high intake of sugars or sucrose confers increased risk of colorectal cancer. The authors investigated the associations of sugars and sucrose intake with colorectal cancer risk in a community-based case–control study in Japan. Methods The study subjects comprised 816 incident cases of colorectal cancer and 815 community controls. Consumption frequencies and portion sizes of 148 food and bev...

  7. Effects of Selected Polysorbate and Sucrose Ester Emulsifiers on the Physicochemical Properties of Astaxanthin Nanodispersions

    OpenAIRE

    Navideh Anarjan; Chin Ping Tan

    2013-01-01

    The effects of selected nonionic emulsifiers on the physicochemical characteristics of astaxanthin nanodispersions produced by an emulsification/evaporation technique were studied. The emulsifiers used were polysorbates (Polysorbate 20, Polysorbate 40, Polysorbate 60 and Polysorbate 80) and sucrose esters of fatty acids (sucrose laurate, palmitate, stearate and oleate). The mean particle diameters of the nanodispersions ranged from 70 nm to 150 nm, depending on the emulsifier used. In the pre...

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

    OpenAIRE

    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 de...

  9. Pontine and Thalamic Influences on Fluid Rewards: III. Anticipatory Contrast for Sucrose and Corn Oil

    OpenAIRE

    Liang, Nu-Chu; Norgren, Ralph; Grigson, Patricia S.

    2011-01-01

    An anticipatory contrast effect (ACE) occurs when, across daily trials, an animal comes to respond less than normally to a first stimulus when it is followed shortly by a second, more preferred solution. Classically, ACE is studied using a low (L) concentration of saccharin or sucrose, followed by access to a higher (H) concentration of sucrose. Subjects in the control condition have two bouts of access to the weaker solution presented on the same schedule. The ACE is measured by the differen...

  10. Sucrose radical-production cross section regarding heavy-ion irradiation

    OpenAIRE

    Nakagawa, Kouichi; Ikota, Nobuo; Anzai, Kazunori

    2008-01-01

    We investigated the sucrose radical-production cross section induced by heavy-ion irradiation. L-alanine was also used in order to compare radical yield and cross section. The stable free radicals after irradiation were analyzed by EPR (electron paramagnetic resonance). The radical yield obtained by the irradiated samples had a logarithmic correlation with the LET (linear energy transfer). Quantitative EPR analyses showed that radical productions for sucrose and L-alanine vary both by differe...

  11. Carbon particle induced foaming of molten sucrose for the preparation of carbon foams

    Energy Technology Data Exchange (ETDEWEB)

    Narasimman, R.; Vijayan, Sujith; Prabhakaran, K., E-mail: kp2952002@gmail.com

    2014-11-15

    Graphical abstract: - Highlights: • An easy method for the preparation of carbon foam from sucrose is presented. • Wood derived activated carbon particles are used to stabilize the molten sucrose foam. • The carbon foams show relatively good mechanical strength. • The carbon foams show excellent CO{sub 2} adsorption and oil absorption properties. • The process could be scaled up for the preparation of large foam bodies. - Abstract: Activated carbon powder was used as a foaming and foam setting agent for the preparation of carbon foams with a hierarchical pore structure from molten sucrose. The rheological measurements revealed the interruption of intermolecular hydrogen bonding in molten sucrose by the carbon particles. The carbon particles stabilized the bubbles in molten sucrose by adsorbing on the molten sucrose–gas interface. The carbon foams obtained at the activated carbon powder to sucrose weight ratios in the range of 0–0.25 had a compressive strength in the range of 1.35–0.31 MPa. The produced carbon foams adsorb 2.59–3.04 mmol/g of CO{sub 2} at 760 mmHg at 273 K and absorb oil from oil–water mixtures and surfactant stabilized oil-in-water emulsions with very good selectivity and recyclability.

  12. A study on alfalfa-dodder relationships by 14C-sucrose incorporation in their tissues

    International Nuclear Information System (INIS)

    Plant-parasite relationships between lesser-dodder (Cuscuta epithymum) and alfalfa (Medicago sativa) are investigated. 14C-sucrose was incorporated via the cut stems of host and parasite into their tissues and the content of the free sugars, keto acids and free amino acids are determined. 14C-sucrose was introduced also in lesser-dodder previously taken from the host-plant and immersed directly into radioactive sucrose. It is shown that the parasite intensively absorbs sucrose from the host-plant tissues using it as a source of energy and as a substrat for different synthetic processes. In the case when the parasite was previously taken away from the host-plant 14C-sucrose taken up directly from the solution was used for the synthesis of various compounds (carbohydrates, amino- and keto acids). The suggestion was made that the respective enzyme systems are present in dodder tissues. The 14C-glucose and 14C-fructose content is an evidence for high invertase hydrolytic activity. The presence of 14C-keto acids shows that the 14C-sucrose incorporated in lesser-dodder tissues without the mediation of the host-plant was used as a respiratory substrate by the degradation following Krebs cycle. (author)

  13. Chronic pramipexole treatment increases tolerance for sucrose in normal and ventral tegmental lesioned rats.

    Directory of Open Access Journals (Sweden)

    David eDARDOU

    2015-01-01

    Full Text Available 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 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 12h 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 3 receptor in the core and the shell regions of the nucleus accumbens. The present results may suggest that long term stimulation of the dopamine 3 receptor in animals induces a strong increase in sucrose consumption, indicating an effect of this receptor on certain pathological aspects of food eating.

  14. Chronic pramipexole treatment increases tolerance for sucrose in normal and ventral tegmental lesioned rats.

    Science.gov (United States)

    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

  15. Coplanar waveguides loaded with a split ring resonator-based microwave sensor for aqueous sucrose solutions

    Science.gov (United States)

    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.

  16. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

    International Nuclear Information System (INIS)

    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 β-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the β-adrenergic pathway, adenylate cyclase activity and β-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. β-Adrenergic receptors were identified in BAT using [125I]iodocyanopindolol. Binding sites had the characteristics of mixed β1- and β2-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 β-adrenergic receptor density due to a loss of the β1-adrenergic subtype. This BAT β-adrenergic receptor downregulation was tissue specific, since myocardial β-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 β-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability

  17. Biological hydrogen production from sucrose and sugar beet by Caldicellulosiruptor saccharolyticus

    Energy Technology Data Exchange (ETDEWEB)

    Panagiotopoulos, John [National Technical Univ. of Athens (Greece); Wageningen UR Food and Biobased Research (Netherlands); Bakker, Robert; Vrieje, Truus de; Claassen, Pieternel [Wageningen UR Food and Biobased Research (Netherlands); Koukios, Emmanuel [National Technical Univ. of Athens (Greece)

    2010-07-01

    Hydrogen production needs to be based on renewable resources in order to be sustainable. Sugar beet is an ideal raw material for fermentative production of hydrogen in the EU and possibly in the USA due to its environmental profile and its potential availability in these areas. In this work, the fermentative production of hydrogen from sucrose of analytical grade and sugar beet extract by pure cultures of Caldicellulosiruptor saccharolyticus was investigated, under uncontrolled and controlled conditions. In the first case, growth of pure cultures of C. saccharolyticus on sucrose derived from sugar beet was compared to growth of the microorganism on sucrose of analytical grade. The production of hydrogen and organic acids (acetate and lactate) from sugar beet was largely equal to or slightly higher than the production of the control. In the second case, fermentation of sugar beet extract at sucrose concentration 10 g/l was comparable to the fermentation on pure sucrose except that the hydrogen yield was slightly higher on sugar beet extract. In particular, hydrogen yields of 2.9 and 3.0 mol/mol hexose were determined in fermentations of sucrose and sugar beet extract, respectively, corresponding to 73% and 75% of the theoretical value of 4 mol hydrogen/mol hexose. Acetic acid was the main product and very low production of lactic acid was observed. (orig.)

  18. Coplanar waveguides loaded with a split ring resonator-based microwave sensor for aqueous sucrose solutions

    International Nuclear Information System (INIS)

    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. (paper)

  19. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

    Energy Technology Data Exchange (ETDEWEB)

    Scarpace, P.J.; Baresi, L.A.; Morley, J.E. (Veterans Administration Medical Center, Los Angeles, CA (USA) Univ. of California, Los Angeles (USA))

    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.

  20. An Arabidopsis mutant impaired in coenzyme A biosynthesis is sugar dependent for seedling establishment.

    Science.gov (United States)

    Rubio, Silvia; Larson, Tony R; Gonzalez-Guzman, Miguel; Alejandro, Santiago; Graham, Ian A; Serrano, Ramón; Rodriguez, Pedro L

    2006-03-01

    Once the plant coenzyme A (CoA) biosynthetic pathway has been elucidated by comparative genomics, it is feasible to analyze the physiological relevance of CoA biosynthesis in plant life. To this end, we have identified and characterized Arabidopsis (Arabidopsis thaliana) T-DNA knockout mutants of two CoA biosynthetic genes, HAL3A and HAL3B. The HAL3A gene encodes a 4'-phosphopantothenoyl-cysteine decarboxilase that generates 4'-phosphopantetheine. A second gene, HAL3B, whose gene product is 86% identical to that of HAL3A, is present in the Arabidopsis genome. HAL3A appears to have a predominant role over HAL3B according to their respective mRNA expression levels. The hal3a-1, hal3a-2, and hal3b mutants were viable and showed a similar growth rate as that in wild-type plants; in contrast, a hal3a-1 hal3b double mutant was embryo lethal. Unexpectedly, seedlings that were null for HAL3A and heterozygous for HAL3B (aaBb genotype) displayed a sucrose (Suc)-dependent phenotype for seedling establishment, which is in common with mutants defective in beta-oxidation. This phenotype was genetically complemented in aaBB siblings of the progeny and chemically complemented by pantethine. In contrast, seedling establishment of Aabb plants was not Suc dependent, proving a predominant role of HAL3A over HAL3B at this stage. Total fatty acid and acyl-CoA measurements of 5-d-old aaBb seedlings in medium lacking Suc revealed stalled storage lipid catabolism and impaired CoA biosynthesis; in particular, acetyl-CoA levels were reduced by approximately 80%. Taken together, these results provide in vivo evidence for the function of HAL3A and HAL3B, and they point out the critical role of CoA biosynthesis during early postgerminative growth. PMID:16415216

  1. Reconstruction and analysis of nutrient-induced phosphorylation networks in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Guangyou eDuan

    2013-12-01

    Full Text Available Elucidating the dynamics of molecular processes in living organisms in response to external perturbations is a central goal in modern systems biology. We investigated the dynamics of protein phosphorylation events in Arabidopsis thaliana exposed to changing nutrient conditions. Phosphopeptide expression levels were detected at five consecutive time points over a time interval of 30 minutes after nutrient resupply following prior starvation. The three tested inorganic, ionic nutrients NH4+, NO3-, PO43- elicited similar phosphosignaling responses that were distinguishable from those invoked by the sugars mannitol, sucrose. When embedded in the protein-protein interaction network of Arabidopsis thaliana, phosphoproteins were found to exhibit a higher degree compared to average proteins. Based on the time-series data, we reconstructed a network of regulatory interactions mediated by phosphorylation. The performance of different network inference methods was evaluated by the observed likelihood of physical interactions within and across different subcellular compartments and based on gene ontology semantic similarity. The dynamic phosphorylation network was then reconstructed using a Pearson correlation method with added directionality based on partial variance differences. The topology of the inferred integrated network corresponds to an information dissemination architecture, in which the phosphorylation signal is passed on to an increasing number of phosphoproteins stratified into an initiation, processing, and effector layer. Specific phosphorylation peptide motifs associated with the distinct layers were identified indicating the action of layer-specific kinases. Despite the limited temporal resolution, combined with information on subcellular location, the available time-series data proved useful for reconstructing the dynamics of the molecular signaling cascade in response to nutrient stress conditions in the plant Arabidopsis thaliana.

  2. Expression Patterns, Activities and Carbohydrate-Metabolizing Regulation of Sucrose Phosphate Synthase, Sucrose Synthase and Neutral Invertase in Pineapple Fruit during Development and Ripening

    Science.gov (United States)

    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. PMID:22949808

  3. Development of an integrated electrochemical biosensor for sucrose and its implementation in a continuous flow system for the simultaneous monitoring of sucrose, fructose and glucose.

    Science.gov (United States)

    Vargas, E; Gamella, M; Campuzano, S; Guzmán-Vázquez de Prada, A; Ruiz, M A; Reviejo, A J; Pingarrón, J M

    2013-02-15

    An integrated amperometric sucrose biosensor involving a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM)-modified gold disk electrode (AuE) and coimmobilization of the enzymes invertase (INV) and fructose dehydrogenase (FDH) as well as the redox mediator tetrathiafulvalene (TTF) by means of a dialysis membrane is reported. Amperometry in stirred solutions at a detection potential of +0.10 V provided a linear calibration plot for sucrose over the 1.2 × 10(-6)-3.0 × 10(-3) mol L(-1) concentration range, with a limit of detection of 3.6 × 10(-7) mol L(-1). The practical usefulness of the biosensor was demonstrated by determining sucrose in condensed milk and in an infant food reference material with good results. Additionally, the biosensor was implemented together with commercial fructose and glucose amperometric biosensors in a continuous flow system to perform the multiplexed quantification of sucrose, fructose and glucose in a single experiment. The operational characteristics of the biosensors in this novel flow system were evaluated and their applicability was demonstrated through the simultaneous determination of the three sugars in the above-mentioned reference material. PMID:23597994

  4. Guard cell-specific upregulation of sucrose synthase 3 reveals that the role of sucrose in stomatal function is primarily energetic.

    Science.gov (United States)

    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

  5. Effects of dietary amylase and sucrose on productivity of cows fed low-starch diets.

    Science.gov (United States)

    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

  6. The influence of temperature, daylength and sucrose concentration on the growth and development of Alstroemeria 'Zebra' in vitro

    Directory of Open Access Journals (Sweden)

    Eleonora Gabryszewska

    2013-12-01

    Full Text Available The influence of temperature, daylength and sucrose concentration on the growth and development of Alstroemeria 'Zebra' in vitro was investigated. Only slightly more lateral rhizomes were formed at 25°C in comparison with 17°C on the medium with BA. Presence of BA in the medium strongly increased number of upright growing shoots and more shoots were formed in temperature 25°C than in temperature 17°C. Rhizome multiplication and formation of upright growing shoots were not significantly influenced by daylength. Sucrose was required for the formation of lateral rhizomes, upright growing shoots and roots. The highest number Of lateral rhizomes was observed on the medium containing 60 and 80 gl-1 sucrose and BA. Presence of BA in the medium with different sucrose concentrations markedly influenced the formation of upright growing shoots; the highest number of shoots was found on the explants cultured on the media with 20 and 30 gl-1 sucrose. Low and high concentrations of sucrose inhibited upright growing shoots formation and their elongation. Rhizogenesis was not observed on rhizomes growing on the medium without sucrose and with 10 gl-1 sucrose, either in the presence or absence of NAA„ The number of roots per plantlet on the medium with NAA increased with increasing sucrose levels. The highest sucrose concentrations slightly inhibited roots formation.

  7. ZINC-INDUCED HYPERLEPTINEMIA IN RATS RELATED TO THE AMELIORATION OF SUCROSE-INDUCED OBESITY WITH ZINC REPLETION

    International Nuclear Information System (INIS)

    Thirty adult albino rats (Rattus rattus) at 6 weeks of age were divided into three groups (ten for each). The first group was fed a standard laboratory diet for 8 weeks (control). The second group was made obese by giving them 32% sucrose solution in addition to the standard laboratory diet .The third group was received zinc supplementation (50 mg zinc acetate/ litre) with their sucrose solution. Body weight of all rats was measured weekly for 8 weeks. At 14 weeks of age, rats were killed and fasting blood samples were obtained. Serum glucose, insulin, cholesterol, triglyceride, leptin, tumour necrosis factor-α and zinc were measured.Results showed remarkable changes in body weights in sucrose fed rats only when compared to control and supplemented zinc rats group. Serum glucose, insulin, cholesterol and triglycerides were significantly increased in sucrose fed rats than both control and sucrose with zinc group. Serum leptin showed significant increase in sucrose fed rats than control and also showed higher significant value in sucrose fed rats supplemented with zinc comparing with sucrose fed rats and control ones. Tumour necrosis factor-? did not show any significant difference between all groups. Serum zinc concentration was decreased significantly in sucrose fed rats as compared to control. On the other hand, it was increased significantly in sucrose fed rats supplemented with zinc than other both groups. It could be concluded that zinc supplementation induced hyperleptinemia caused ameliorating effects in obese rats

  8. EVIDENCE OF DIFFERENTIAL PH REGULATION OF THE ARABIDOPSIS VACUOLAR CA2+/H+ ANTIPORTERS CAX1 AND CAX2

    Science.gov (United States)

    The Arabidopsis Ca(2+)/H(+) antiporters cation exchanger (CAX) 1 and 2 utilise an electrochemical gradient to transport Ca(2+) into the vacuole to help mediate Ca(2+) homeostasis. Previous whole plant studies indicate that activity of Ca(2+)/H(+) antiporters is regulated by pH. However, the pH regul...

  9. MADS on the move : a study on MADS domain protein function and movement during floral development in Arabidopsis thaliana

    NARCIS (Netherlands)

    Urbanus, S.L.

    2010-01-01

    In this thesis we investigated the behaviour of fluorescently-tagged MADS domain proteins during floral development in the model plant Arabidopsis thaliana, and explored the importance of intercellular transport via plasmodesmata for MADS domain transcription factor functioning. The MADS domain tran

  10. Functional identification of an Arabidopsis snf4 ortholog by screening for heterologous multicopy suppressors of snf4 deficiency in yeast

    DEFF Research Database (Denmark)

    Kleinow, T.; Bhalerao, R.; Breuer, F.; Umeda, M.; Salchert, Klaus-Dieter; Koncz, C.

    2000-01-01

    , zinc-finger factors AZF2 and ZAT10, as well as orthologs of hexose/UDP-hexose transporters, calmodulin, SMC1-cohesin and Snf4. Here we describe the characterization of AtSNF4, a functional Arabidopsis Snf4 ortholog, that interacts with yeast Snf1 and specifically binds to the C-terminal regulatory...

  11. Arabidopsis CDS blastp result: AK119708 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119708 002-157-E08 At1g28330.1 dormancy-associated protein, putative (DRM1) identical to dormancy...-associated protein [Arabidopsis thaliana] GI:2995990; similar to dormancy-associated protei

  12. Arabidopsis CDS blastp result: AK060981 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK060981 006-202-H08 At1g28330.1 dormancy-associated protein, putative (DRM1) identical to dormancy...-associated protein [Arabidopsis thaliana] GI:2995990; similar to dormancy-associated protei

  13. Arabidopsis CDS blastp result: AK111736 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111736 J023047L09 At1g68370.1 gravity -responsive protein / altered response to gravity ... protein ... (ARG1) identical to Altered Response to Gravity ... [Arabidopsis thaliana] GI:4249662; contains Pfam p ...

  14. Arabidopsis CDS blastp result: AK070093 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK070093 J023041M10 At2g39290.1 phosphatidylglycerolphosphate synthase (PGS1) identical to phosphati...dylglycerolphosphate synthase GI:13365519 from [Arabidopsis thaliana] 7e-78 ...

  15. Arabidopsis CDS blastp result: AK060009 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK060009 006-302-D03 At2g39290.1 phosphatidylglycerolphosphate synthase (PGS1) identical to phosphati...dylglycerolphosphate synthase GI:13365519 from [Arabidopsis thaliana] 8e-71 ...

  16. Arabidopsis CDS blastp result: AK058419 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058419 001-015-D06 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to S ... P|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  17. Arabidopsis CDS blastp result: AK073225 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK073225 J033023C04 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to SP ... |O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  18. Arabidopsis CDS blastp result: AK102695 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102695 J033103F21 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  19. Arabidopsis CDS blastp result: AK102134 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102134 J033085F12 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  20. Arabidopsis CDS blastp result: AK066835 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066835 J013087I16 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-171 ...

  1. Arabidopsis CDS blastp result: AK065259 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK065259 J013002J18 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  2. Arabidopsis CDS blastp result: AK100523 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100523 J023100P04 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  3. Arabidopsis CDS blastp result: AK288002 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288002 J075110B01 At1g68510.1 68414.m07826 LOB domain protein 42 ... / lateral organ boundaries do ... main protein 42 ... (LBD42 ) identical to LOB DOMAIN 42 ... [Arabidopsis th ...

  4. Arabidopsis CDS blastp result: AK241043 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 2e-41 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  5. Arabidopsis CDS blastp result: AK243135 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 7e-43 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  6. Arabidopsis CDS blastp result: AK111785 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111785 J023089N11 At5g62310.1 incomplete root hair ... elongation (IRE) / protein kinase, putative ... nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  7. Arabidopsis CDS blastp result: AK243050 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243050 J100011E04 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  8. Arabidopsis CDS blastp result: AK242758 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242758 J090051H03 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  9. Arabidopsis CDS blastp result: AK242717 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242717 J090043H19 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  10. Arabidopsis CDS blastp result: AK288095 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288095 J075191E21 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  11. Arabidopsis CDS blastp result: AK242638 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242638 J090023J02 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  12. Arabidopsis CDS blastp result: AK242651 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242651 J090026B08 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  13. Arabidopsis CDS blastp result: AK287631 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287631 J065073J24 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  14. Arabidopsis CDS blastp result: AK288923 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288923 J090081P06 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  15. Arabidopsis CDS blastp result: AK242271 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242271 J075187A19 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  16. Arabidopsis CDS blastp result: AK242681 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242681 J090032N04 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  17. Arabidopsis CDS blastp result: AK243656 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243656 J100088L22 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  18. Arabidopsis CDS blastp result: AK241519 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241519 J065170E12 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  19. Arabidopsis CDS blastp result: AK240655 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240655 J023135E11 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  20. Arabidopsis CDS blastp result: AK242733 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242733 J090047O22 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  1. Arabidopsis CDS blastp result: AK242859 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242859 J090073L24 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  2. Arabidopsis CDS blastp result: AK243187 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243187 J100039E11 At5g62310.1 68418.m07822 incomplete root hair ... elongation (IRE) / protein kin ... putative nearly identical to IRE (incomplete root hair ... elongation) [Arabidopsis thaliana] gi|6729346|dbj| ...

  3. Arabidopsis CDS blastp result: AK242550 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242550 J080319D10 At2g35630.1 68415.m04369 microtubule organization 1 protein (MO...R1) identical to microtubule organization 1 protein GI:14317953 from [Arabidopsis thaliana] 5e-44 ...

  4. Arabidopsis CDS blastp result: AK101368 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK101368 J033035L13 At5g24270.1 calcineurin B-like protein, putative / calcium sensor ... homolog (S ... OS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  5. Arabidopsis CDS blastp result: AK111570 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111570 J013071C24 At5g24270.1 calcineurin B-like protein, putative / calcium sensor ... homolog (S ... OS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  6. Arabidopsis CDS blastp result: AK243065 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243065 J100015N03 At5g24270.1 68418.m02855 calcineurin B-like protein, putative / calcium sensor ... or homolog (SOS3) identical to calcium sensor ... homolog [Arabidopsis thaliana] GI:3309575; similar ...

  7. The fifth international conference on Arabidopsis research

    Energy Technology Data Exchange (ETDEWEB)

    Hangarter, R.; Scholl, R.; Davis, K.; Feldmann, K.

    1993-12-31

    This volume contains abstracts of oral and poster presentations made in conjunction with the Fifth International Conference on Arabidopsis Research held August 19--22, 1993 at the Ohio State University, Columbus, Ohio.

  8. Arabidopsis CDS blastp result: AK070528 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK070528 J023060D13 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... supe ... roxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  9. Arabidopsis CDS blastp result: AK119904 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK119904 002-182-A05 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  10. Arabidopsis CDS blastp result: AK104030 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104030 001-020-C01 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  11. Arabidopsis CDS blastp result: AK104160 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK104160 006-211-E09 At3g10920.1 superoxide dismutase [Mn], mitochondrial (SODA) / manganese ... sup ... eroxide dismutase (MSD1) identical to manganese ... superoxide dismutase [Arabidopsis thaliana] gi|327 ...

  12. Arabidopsis CDS blastp result: AK287459 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287459 J043019O07 At4g37000.1 68417.m05242 accelerated cell death ... 2 (ACD2) identical to accele ... rated cell death ... 2 (ACD2) GI:12484129 from [Arabidopsis thaliana] 4 ...

  13. Arabidopsis CDS blastp result: AK288034 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288034 J075140H07 At4g37000.1 68417.m05242 accelerated cell death ... 2 (ACD2) identical to accele ... rated cell death ... 2 (ACD2) GI:12484129 from [Arabidopsis thaliana] 5 ...

  14. Arabidopsis CDS blastp result: AK111576 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111576 J013075J23 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly id...entical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profile

  15. Arabidopsis CDS blastp result: AK120838 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK120838 J023022B11 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly id...entical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profile

  16. Arabidopsis CDS blastp result: AK111921 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111921 001-013-A10 At1g01510.1 C-terminal binding protein (ANGUSTIFOLIA) nearly i...dentical to C-terminal binding protein ANGUSTIFOLIA [Arabidopsis thaliana] GI:15408535; contains Pfam profil

  17. Arabidopsis CDS blastp result: AK073140 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK073140 J033022I01 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-168 ...

  18. Arabidopsis CDS blastp result: AK120439 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK120439 J013098H20 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-154 ...

  19. Arabidopsis CDS blastp result: AK121378 [KOME

    Lifescience Database Archive (English)

    Full Text Available me 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK121378 J023127F14 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isozy... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-142 ...

  20. Arabidopsis CDS blastp result: AK063856 [KOME

    Lifescience Database Archive (English)

    Full Text Available yme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains a Ser/Thr protein...AK063856 001-122-D05 At2g39840.1 serine/threonine protein phosphatase PP1 isozyme 4 (TOPP4) / phosphoprotein... phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphatase PP1 isoz... phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 6e-46 ...

  1. Terpene Specialized Metabolism in Arabidopsis thaliana

    OpenAIRE

    Tholl, Dorothea; Lee, Sungbeom

    2011-01-01

    Terpenes constitute the largest class of plant secondary (or specialized) metabolites, which are compounds of ecological function in plant defense or the attraction of beneficial organisms. Using biochemical and genetic approaches, nearly all Arabidopsis thaliana (Arabidopsis) enzymes of the core biosynthetic pathways producing the 5-carbon building blocks of terpenes have been characterized and closer insight has been gained into the transcriptional and posttranscriptional/translational mech...

  2. Generation Means Analysis of Seed Sucrose Content in Cowpea (Vigna unguiculata L. Walp.

    Directory of Open Access Journals (Sweden)

    J.B. Noubissie Tchiagam

    2011-11-01

    Full Text Available The sucrose concentration of seeds is an important component of the taste in cowpea (Vigna unguiculata L. Walp.. The objective of this research was to estimate the heritability, to investigate the mode of genetic control and to evaluate the potential for genetic improvement of sucrose content in cowpea using generation’s means analysis. F1 and F2 generations as well as backcross populations (BCP1 and BCP2 were produced in three hybrid combinations by crosses of four selected cultivars. The sucrose level was measured via a High Performance Liquid Chromatography (HPLC system. The range of variation in sucrose content among tested varieties was from 1.88 mg/g (Lori to 5.32 mg/g (C93W-24-125. Broad-sense heritability (h2 was of a moderate 58.50% to high 68.12% value and no transgressive segregation was observed. Narrow-sense heritability (39.47 to 47.83% and heterosis (-20.00 to - 5.94% values and gene effects analysis suggested that the sucrose content is controlled by additive and non-additive genes. At 10% level of selection, an increase of 19.60 to 33.64% was predicted after one cycle. Epistasis was significant in most of crosses and at least five genes affected the sucrose accumulation in cowpea seeds. These results suggested that breeding for increased sucrose content in the seeds of cowpea can be quite successful through recurrent selection in later generations.

  3. Intestinal sugar transport

    Institute of Scientific and Technical Information of China (English)

    Laurie A Drozdowski; Alan BR Thomson

    2006-01-01

    Carbohydrates are an important component of the diet.The carbohydrates that we ingest range from simple monosaccharides (glucose, fructose and galactose) to disaccharides (lactose, sucrose) to complex polysaccharides. Most carbohydrates are digested by salivary and pancreatic amylases, and are further broken down into monosaccharides by enzymes in the brush border membrane (BBM) of enterocytes. For example, lactase-phloridzin hydrolase and sucraseisomaltase are two disaccharidases involved in the hydrolysis of nutritionally important disaccharides. Once monosaccharides are presented to the BBM, mature enterocytes expressing nutrient transporters transport the sugars into the enterocytes. This paper reviews the early studies that contributed to the development of a working model of intestinal sugar transport, and details the recent advances made in understanding the process by which sugars are absorbed in the intestine.

  4. Invertase and sucrose synthase activities in coffee plants sprayed with sucrose solution Atividade de invertases e sacarose sintase em plantas de cafeeiro pulverizadas com solução de sacarose

    OpenAIRE

    José Carlos da Silva; José Donizeti Alves; Amauri Alves de Alvarenga; Marcelo Murad Magalhães; Dárlan Einstein do Livramento; Daniela Deitos Fries

    2003-01-01

    One management practice of which the efficiency has not yet been scientifically tested is spraying coffee plants with diluted sucrose solutions as a source of carbon for the plant. This paper evaluates the effect of foliar spraying with sugar on the endogenous level of carbohydrates and on the activities of invertase and sucrose synthase in coffee (Coffea arabica L.) seedlings with reduced (low) and high (normal) levels of carbon reserve. The concentrations used were 0.5 and 1.0% sucrose, and...

  5. Nitric oxide induces the alternative oxidase pathway in Arabidopsis seedlings deprived of inorganic phosphate

    OpenAIRE

    Royo, Beatriz; Moran, Jose F.; Ratcliffe, R. George; Gupta, Kapuganti J.

    2015-01-01

    Phosphate starvation compromises electron flow through the cytochrome pathway of the mitochondrial electron transport chain, and plants commonly respond to phosphate deprivation by increasing flow through the alternative oxidase (AOX). To test whether this response is linked to the increase in nitric oxide (NO) production that also increases under phosphate starvation, Arabidopsis thaliana seedlings were grown for 15 d on media containing either 0 or 1mM inorganic phosphate. The effects of th...

  6. Collection of apoplastic fluids from Arabidopsis thaliana leaves

    DEFF Research Database (Denmark)

    Madsen, Svend Roesen; Nour-Eldin, Hussam Hassan; Halkier, Barbara Ann

    2016-01-01

    The leaf apoplast comprises the extracellular continuum outside cell membranes. A broad range of processes take place in the apoplast, including intercellular signaling, metabolite transport, and plant-microbe interactions. To study these processes, it is essential to analyze the metabolite content...... in apoplastic fluids. Due to the fragile nature of leaf tissues, it is a challenge to obtain apoplastic fluids from leaves. Here, methods to collect apoplastic washing fluid and guttation fluid from Arabidopsis thaliana leaves are described....

  7. Molecular Biology, Biochemistry and Cellular Physiology of Cysteine Metabolism in Arabidopsis thaliana

    OpenAIRE

    Hell, Rüdiger; Wirtz, Markus

    2011-01-01

    Cysteine is one of the most versatile molecules in biology, taking over such different functions as catalysis, structure, regulation and electron transport during evolution. Research on Arabidopsis has contributed decisively to the understanding of cysteine synthesis and its role in the assimilatory pathways of S, N and C in plants. The multimeric cysteine synthase complex is present in the cytosol, plastids and mitochondria and forms the centre of a unique metabolic sensing and signaling sys...

  8. Blocking the Metabolism of Starch Breakdown Products in Arabidopsis Leaves Triggers Chloroplast Degradation

    OpenAIRE

    Stettler, Michaela; Eicke, Simona; Mettler, Tabea; Messerli, Gaëlle; Hörtensteiner, Stefan; Zeeman, Samuel C.

    2009-01-01

    In most plants, a large fraction of photo-assimilated carbon is stored in the chloroplasts during the day as starch and remobilized during the subsequent night to support metabolism. Mutations blocking either starch synthesis or starch breakdown in Arabidopsis thaliana reduce plant growth. Maltose is the major product of starch breakdown exported from the chloroplast at night. The maltose excess 1 mutant (mex1), which lacks the chloroplast envelope maltose transporter, accumulates high levels...

  9. Effects of ruminal doses of sucrose, lactose, and corn starch on ruminal fermentation and expression of genes in ruminal epithelial cells.

    Science.gov (United States)

    Oba, M; Mewis, J L; Zhining, Z

    2015-01-01

    The objective was to evaluate effects of a ruminal dose of sucrose, lactose, and corn starch on ruminal fermentation and expression of genes in ruminal epithelial cells. Six ruminally cannulated nonlactating nonpregnant Holstein cows (body weight=725±69.6kg) were assigned to treatments in a 3×3 Latin square design with 7-d periods; 1d for data and sample collection followed by a 6-d washout period. Cows were fed a diet containing whole-crop barley silage and dry ground corn, and dietary neutral detergent fiber and crude protein contents were 41.8 and 13.2% [dry matter (DM) basis], respectively. Treatment was a pulse-dose of sucrose, lactose, and corn starch (3.0, 3.0, and 2.85kg of DM, respectively; providing similar amounts of hexose across the treatments) through the ruminal cannulas. All treatments were given with alfalfa silage (1.75kg DM) to prevent acute rumen acidosis. Rumen pH was continuously monitored, and rumen fluid was sampled at 0, 30, 60, 90, 120, 150, and 180min after the dose. In addition, ruminal papillae were sampled from the ventral sac at 180min after the dose. Ruminal dosing with sucrose and lactose, compared with corn starch, increased ruminal total volatile fatty acid concentration and molar proportion of butyrate from 60 to 180min after the dose, and expression of genes for sodium hydrogen exchanger isoforms 1 and 2, and ATPase isoform 1 in ruminal epithelial cells. Ruminal dosing with sucrose, compared with lactose and corn starch, decreased rumen pH from 120 to 180min after the dose and molar proportion of acetate in ruminal fluid from 60 to 150min after the dose, and increased molar proportion of propionate in ruminal fluid from 60 to 150min, and expression of genes involved in butyrate metabolism (3-hydroxy-3-methylglutaryl-coenzyme A synthase isoform 1) and anion exchange across ruminal apical cell membrane (putative anion transporter isoform 1). These results suggest that replacing dietary starch with sugars may affect ruminal

  10. Safety and efficacy of aspartame-based liquid versus sucrose-based liquids used for dilution in oral sodium phosphate solutions for colonoscopy preparations.

    Science.gov (United States)

    Chamberlain, Sherman M; Balart, J Carter; Sideridis, Kostas; Salek, Jefrey; Sridhar, Subbaramiah; Thompson, William O

    2007-11-01

    The aim of this study was to investigate whether an oral sodium phosphate solution (OSPS) mixed with aspartame-based clear liquids as the diluent would yield improved colon cleansing results compared to an OSPS mixed with sucrose-based liquids as the diluent. Fifty-one patients undergoing colonoscopy were prospectively randomized into two groups to receive different OSPS colonoscopy preparations, with sucrose-based or aspartame-based liquids used as diluents. The primary end point was the quality of the colonoscopy preparation and secondary end points were serum electrolytes before and after preparations. No significant difference in colonoscopy preparation quality was seen between the two OSPS diluent groups (Mantel-Haenzel chi (2) = 0.795, P = 0.484). There were no significant differences in mean electrolyte shifts of sodium, potassium, blood urea nitrogen (BUN), creatinine (Cr), or BUN/Cr ratios between the two groups. There was a statistically significant increase in serum phosphorous in the aspartame-based group compared to the sucrose-based diluent group (P = 0.021). In conclusion, there was no clinically detectable difference in colonoscopy preparation quality between the two OSPS diluent groups. This study suggests that passive fluid transport by aquaporins may well be the major mediator of fluid shifts in the study subjects. This result suggests the potential importance of aquaporins and minimizes the importance of sodium glucose cotransporter SGLT1 in fluid and electrolyte transport in the human gastrointestinal tract. Aspartame or its constituent amino acids may enhance phosphate absorption across the human small intestine. PMID:17406813

  11. Mutations in a new Arabidopsis cyclophilin disrupt its interaction with protein phosphatase 2A

    Science.gov (United States)

    Jackson, K.; Soll, D.; Evans, M. L. (Principal Investigator)

    1999-01-01

    The heterotrimeric protein phosphatase 2A (PP2A) is a component of multiple signaling pathways in eukaryotes. Disruption of PP2A activity in Arabidopsis is known to alter auxin transport and growth response pathways. We demonstrated that the regulatory subunit A of an Arabidopsis PP2A interacts with a novel cyclophilin, ROC7. The gene for this cyclophilin encodes a protein that contains a unique 30-amino acid extension at the N-terminus, which distinguishes the gene product from all previously identified Arabidopsis cyclophilins. Altered forms of ROC7 cyclophilin with mutations in the conserved DENFKL domain did not bind to PP2A. Unlike protein phosphatase 2B, PP2A activity in Arabidopsis extracts was not affected by the presence of the cyclophilin-binding molecule cyclosporin. The ROC7 transcript was expressed to high levels in all tissues tested. Expression of an ROC7 antisense transcript gave rise to increased root growth. These results indicate that cyclophilin may have a role in regulating PP2A activity, by a mechanism that differs from that employed for cyclophilin regulation of PP2B.

  12. Tethering Complexes in the Arabidopsis Endomembrane System.

    Science.gov (United States)

    Vukašinović, Nemanja; Žárský, Viktor

    2016-01-01

    Targeting of endomembrane transport containers is of the utmost importance for proper land plant growth and development. Given the immobility of plant cells, localized membrane vesicle secretion and recycling are amongst the main processes guiding proper cell, tissue and whole plant morphogenesis. Cell wall biogenesis and modification are dependent on vectorial membrane traffic, not only during normal development, but also in stress responses and in plant defense against pathogens and/or symbiosis. It is surprising how little we know about these processes in plants, from small GTPase regulation to the tethering complexes that act as their effectors. Tethering factors are single proteins or protein complexes mediating first contact between the target membrane and arriving membrane vesicles. In this review we focus on the tethering complexes of the best-studied plant model-Arabidopsis thaliana. Genome-based predictions indicate the presence of all major tethering complexes in plants that are known from a hypothetical last eukaryotic common ancestor (LECA). The evolutionary multiplication of paralogs of plant tethering complex subunits has produced the massively expanded EXO70 family, indicating a subfunctionalization of the terminal exocytosis machinery in land plants. Interpretation of loss of function (LOF) mutant phenotypes has to consider that related, yet clearly functionally-specific complexes often share some common core subunits. It is therefore impossible to conclude with clarity which version of the complex is responsible for the phenotypic deviations observed. Experimental interest in the analysis of plant tethering complexes is growing and we hope to contribute with this review by attracting even more attention to this fascinating field of plant cell biology. PMID:27243010

  13. Amyloplast movement and gravityperception in Arabidopsis endoderm

    Science.gov (United States)

    Tasaka, M.; Saito, T.; Morita, M. T.

    Gravitropism of higher plant is a growth response regulating the orientation of organs elongation, which includes four sequential steps, the perception of gravistimulus, transduction of the physical stimulus to chemical signal, transmission of the signal, and differential cell elongation depending on the signal. To elucidate the molecular mechanism of these steps, we have isolated a number of Arabidopsis mutants with abnormal shoot gravitropic response. zig (zigzag)/sgr4(shoot gravitropism 4) shows little gravitropism in their shoots. Besides, their inflorescence stems elongate in a zigzag-fashion to bend at each node. ZIG encodes a SNARE, AtVTI11. sgr3 with reduced gravitropic response in inflorescence stems had a missense mutation in other SNARE, AtVAM3. These two SNAREs make a complex in the shoot endoderm cells that are gravity-sensing cells, suggesting that the vesicle transport from trans-Golgi network (TGN) to prevacuolar compartment (PVC) and/or vacuole is involved in gravitropism. Abnormal vesicular/vacuolar structures were observed in several tissues of both mutants. Moreover, SGR2 encodes phospholipase A1-like protein that resides in the vacuolar membrane. Endodermis-specific expression of these genes could complement gravitropism in each mutant. In addition, amyloplasts thought to be statoliths localized abnormally in their endoderm cells. These results strongly suggest that formation and function of vacuole in the endoderm cells are important for amyloplasts sedimentation, which is involved in the early process of shoot gravitropism. To reveal this, we constructed vertical stage microscope system to visualize the behavior of amyloplasts and vacuolar membrane in living endodermal cells. We hope to discuss the mechanism of gravity perception after showing their movements.

  14. Pumilio Puf domain RNA-binding proteins in Arabidopsis.

    Science.gov (United States)

    Abbasi, Nazia; Park, Youn-Il; Choi, Sang-Bong

    2011-03-01

    Pumilio proteins are a class of RNA-binding proteins harboring Puf domains (or PUM-HD; Pumilio-Homology Domain), named after the founding members, Pumilio (from Drosophila melanogaster) and FBF (Fem-3 mRNA-Binding Factor from Caenorhabditis elegans). The domains contain multiple tandem repeats each of which recognizes one RNA base and is comprised of 35-39 amino acids. Puf domain proteins have been reported in organisms ranging from single-celled yeast to higher multicellular eukaryotes, such as humans and plants. In yeast and animals, they are involved in a variety of posttranscriptional RNA metabolism including RNA decay, RNA transport, rRNA processing and translational repression. However, their roles in plants are largely unknown. Recently, we have characterized the first member of the Puf family of RNA-binding proteins, APUM23, in Arabidopsis. Here, we discuss and summarize the diverse roles and targets of Puf proteins previously reported in other organisms and then highlight the potential regulatory roles of Puf proteins in Arabidopsis, using our recent study as an example. PMID:21350339

  15. Degradation of Sucrose and Nitrate Over Titania Coated Nano-hematite Photocatalysts

    International Nuclear Information System (INIS)

    Photodegradation of sucrose and/or nitrate in aqueous solutions was studied over the titania coated nano-hematite photocatalysts under near-UV irradiation. The efficiency of the photocatalytic oxidation and reduction of these coated particles was compared to the prepared single phase TiO2. It was found that in different environments (O2 or N2) the particles showed differences in the photocatalytic efficiency due to the different reaction mechanisms. Effect of nitrate on sucrose degradation was investigated. In aerobic conditions, sucrose was degraded effectively while nitrate reduction was insignificant due to the fast reoxidation of nitrite by O2 in the dark and by OH. in homogeneous reaction. Since nitrite competes with sucrose for hydroxyl radicals, it has an adverse effect when the aerobic system contains both substrates. Since reoxidation was suppressed in N2 conditions, greater reduction of nitrate was observed. The result showed clearly that in the absence of O2, CO2 production from sucrose mineralisation was limited by the amount of oxygen produced from the nitrate decomposition. Partial photodissolution of Fe ions for the coated samples was also observed in both environments

  16. Pollen Morphology and Sucrose Giving on Stigma Relation with Incopability of Sweetpotato [Ipomoea Batatas (L. L.

    Directory of Open Access Journals (Sweden)

    Febri Adi Susanto

    2013-09-01

    Full Text Available This research aimed to increase the success rate of self-pollination in sweetpotato through sucrose treatment on stigma and pollen nuclei check. Various concentration of sucrose was applied on the stigma. Prior to the crosses, the stigma was excised and lubricated with sucrose. Pedicel was lubricated with 100 ppm of 2,4 D in lanolin. The result showed that the stigma of both varieties was longer than the anther. Papua Solosa showed 94,7% anther dehiscence and 70, 25% pollen viability; whereas MSU 03028-10 showed 87, 3% anther dehiscence and 87, 84% pollen viability. Both of these varieties showed receptive stigma. Sucrose level in compatible pollination was lower than in incompatible pollination. Sugar in 50 ppm concentration can increase the formation of fruit in self-pollination of Papua Solosa varieties from 0% to 70%; 0% to 60% in self-pollination of MSU 03028-10; and 10% to 90% of Papua Solosa>sucrose treatment using 50 ppm concentration, stigma excision, and 100 ppm of 2,4D in lanolin.

  17. Argentine ant (Hymenoptera: Formicidae) trail pheromone enhances consumption of liquid sucrose solution.

    Science.gov (United States)

    Greenberg, L; Klotz, J H

    2000-02-01

    We investigated whether the Argentine ant, Linepithema humile (Mayr), trail pheromone, Z9-16:Ald, could enhance recruitment to and consumption of liquid sucrose solutions. All tests were done as paired comparisons with a 10% sucrose solution as food. In the laboratory, mixing 20 microl of a 10-microg/ml solution of the pheromone with 50 microl of the 10% sucrose solution increased the number of ants feeding by >150%. In a field test, we combined the trail pheromone with a 10% sucrose solution in 50-ml vials. These vials were covered with a plastic membrane that has 1.5-mm-diameter holes punched uniformly across its surface. Ants could drink from the holes after the vials were inverted. For half of the vials, 1 microg of the pheromone was put onto the plastic membrane before the vials were filled with a 10% sucrose solution. The remaining vials had no pheromone on the plastic membrane. After 4 h we measured the consumption in each vial. Bait consumption with the pheromone was enhanced by 29%. In a 2nd series of tests, vials were left outside for 24 h. The consumption rate was 33% higher with the pheromone compared with the controls that didn't have pheromone. PMID:14658521

  18. Effect of diet on preference and intake of sucrose in obese prone and resistant rats.

    Directory of Open Access Journals (Sweden)

    Frank A Duca

    Full Text Available Increased orosensory stimulation from palatable diets and decreased feedback from gut signals have been proposed as contributing factors to obesity development. Whether altered taste functions associated with obesity are common traits or acquired deficits to environmental factors, such as a high-energy (HE-diet, however, is not clear. To address this, we examined preference and sensitivity of increasing concentrations of sucrose solutions in rats prone (OP and resistant (OR to obesity during chow and HE feeding and measured lingual gene expression of the sweet taste receptor T1R3. When chow-fed, OP rats exhibited reduced preference and acceptance of dilute sucrose solutions, sham-fed less sucrose compared to OR rats, and had reduced lingual T1R3 gene expression. HE-feeding abrogated differences in sucrose preference and intake and lingual T1R3 expression between phenotypes. Despite similar sucrose intakes however, OP rats consumed significantly more total calories during 48-h two-bottle testing compared to OR rats. The results demonstrate that OP rats have an innate deficit for sweet taste detection, as illustrated by a reduction in sensitivity to sweets and reduced T1R3 gene expression; however their hyperphagia and subsequent obesity during HE-feeding is most likely not due to altered consumption of sweets.

  19. Influence of solid-state acidity on the decomposition of sucrose in amorphous systems. I.

    Science.gov (United States)

    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

  20. Role of plaque in the clearance of salivary sucrose and its influence on salivary ph

    Directory of Open Access Journals (Sweden)

    A Kumar

    2011-01-01

    Full Text Available Background: The prevalence of dental caries in children, in India, is higher than many of the industrialized countries. The sugar most commonly associated with dental caries is sucrose, as the microorganisms in the dental plaque have the ability to convert this dietary constituent into various organic acids. Aims and Objectives: This study was conducted to study the effect of the presence of plaque on the salivary clearance of sucrose and to study the effect of the presence of plaque on salivary pH, following sucrose clearance. Materials and Methods: Salivary sucrose determination was done by using the anthrone technique. A Digital MHOS pH meter estimated the salivary pH. Results: Presence of plaque increased the salivary sucrose clearance time and decreased the salivary pH at various time intervals. Conclusions: The microbial etiology of dental caries is the dynamic relationship among the dental plaque microbiota, dietary carbohydrates, saliva and pH lowering, and the cariogenic potential of the dental plaque. Caries occur preferentially in the dentition sites characterized by high exposure to carbohydrate and diminished salivary effect.

  1. Combined iron sucrose and protoporphyrin treatment protects against ischemic and toxin-mediated acute renal failure.

    Science.gov (United States)

    Zager, Richard A; Johnson, Ali C M; Frostad, Kirsten B

    2016-07-01

    Tissue preconditioning, whereby various short-term stressors initiate organ resistance to subsequent injury, is well recognized. However, clinical preconditioning of the kidney for protection against acute kidney injury (AKI) has not been established. Here we tested whether a pro-oxidant agent, iron sucrose, combined with a protoporphyrin (Sn protoporphyrin), can induce preconditioning and protect against acute renal failure. Mice were pretreated with iron sucrose, protoporphyrin, cyanocobalamin, iron sucrose and protoporphyrin, or iron sucrose and cyanocobalamin. Eighteen hours later, ischemic, maleate, or glycerol models of AKI were induced, and its severity was assessed the following day (blood urea nitrogen, plasma creatinine concentrations; post-ischemic histology). Agent impact on cytoprotective gene expression (heme oxygenase 1, hepcidin, haptoglobin, hemopexin, α1-antitrypsin, α1-microglobulin, IL-10) was assessed as renal mRNA and protein levels. AKI-associated myocardial injury was gauged by plasma troponin I levels. Combination agent administration upregulated multiple cytoprotective genes and, unlike single agent administration, conferred marked protection against each tested model of acute renal failure. Heme oxygenase was shown to be a marked contributor to this cytoprotective effect. Preconditioning also blunted AKI-induced cardiac troponin release. Thus, iron sucrose and protoporphyrin administration can upregulate diverse cytoprotective genes and protect against acute renal failure. Associated cardiac protection implies potential relevance to both AKI and its associated adverse downstream effects. PMID:27165818

  2. Apple pectin affects the efficacy of epigallocatechin gallate on oral sucrose tolerance test in adult mice.

    Science.gov (United States)

    Tamura, M; Hori, S

    2011-11-01

    Epigallocatechin gallate (EGCg), a dietary polyphenol and a major tea catechin, is a known sucrase inhibitor. Since dietary pectin is known to modulate some of the functions of the gastrointestinal tract, we investigated whether it could specifically affect the efficacy of EGCg on an oral sucrose tolerance test in mice. Male Crj:CD-1 (ICR) mice (seven weeks old) were randomly divided into two groups and fed a 5 % apple pectin (PE) or 5 % cellulose (CE) diet (control diet) for 28 days. After the experimental diet period, all mice were fasted overnight. A volume of 0.2 mL EGCg (20 mg/mL) was orally administered to all the mice by stainless steel feeding needle via injection syringe and a sucrose tolerance test was performed. The blood glucose levels were measured in blood collected from the tail vein using the OneTouch® Ultra® blood glucose monitoring system. Blood glucose levels at 30 minutes and 60 minutes after sucrose loading in the PE group were significantly higher than initial blood glucose levels. However, blood glucose levels at 30 minutes, 60 minutes, and 120 minutes after sucrose loading in the CE group were not significantly higher than initial blood glucose levels. After laparotomy, plasma lipids were also measured. Plasma triglyceride concentrations were significantly greater in the PE group than in the CE (control) group. This demonstrates that dietary pectin can affect the efficacy of EGCg on the oral sucrose tolerance test in mice. PMID:22673921

  3. Effects of Selected Polysorbate and Sucrose Ester Emulsifiers on the Physicochemical Properties of Astaxanthin Nanodispersions

    Directory of Open Access Journals (Sweden)

    Navideh Anarjan

    2013-01-01

    Full Text Available The effects of selected nonionic emulsifiers on the physicochemical characteristics of astaxanthin nanodispersions produced by an emulsification/evaporation technique were studied. The emulsifiers used were polysorbates (Polysorbate 20, Polysorbate 40, Polysorbate 60 and Polysorbate 80 and sucrose esters of fatty acids (sucrose laurate, palmitate, stearate and oleate. The mean particle diameters of the nanodispersions ranged from 70 nm to 150 nm, depending on the emulsifier used. In the prepared nanodispersions, the astaxanthin particle diameter decreased with increasing emulsifier hydrophilicity and decreasing carbon number of the fatty acid in the emulsifier structure. Astaxanthin nanodispersions with the smallest particle diameters were produced with Polysorbate 20 and sucrose laurate among the polysorbates and the sucrose esters, respectively. We also found that the Polysorbate 80- and sucrose oleate-stabilized nanodispersions had the highest astaxanthin losses (i.e., the lowest astaxanthin contents in the final products among the nanodispersions. This work demonstrated the importance of emulsifier type in determining the physicochemical characteristics of astaxanthin nano-dispersions.

  4. Activation of physiological stress responses by a natural reward: Novel vs. repeated sucrose intake.

    Science.gov (United States)

    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. PMID:25747321

  5. ESR investigation of L-α-alanine and sucrose radicals produced by heavy-ion irradiation

    International Nuclear Information System (INIS)

    We investigated sucrose and L-α-alanine radicals produced by heavy (particle) ion irradiation with various LETs (linear energy transfer). The impact of the heavy ions on the samples produced stable free radicals, which were analyzed by ESR (electron spin resonance). Identical spectra were measured after one year. The obtained spectral patterns were the same as those for helium (He), carbon (C), and neon (Ne) ions irradiation. The absorbed dose dependences for the irradiated sucrose and alanine samples were examined. The ESR response has a linear relation with the absorbed dose. The ESR response at 60 Gy was slightly lower than a linear line for sucrose; however, the response showed good linearity for the alanine. In addition, the total spin concentration obtained by heavy-ion irradiation correlated logarithmically with the LET. Qualitative ESR analyse showed that the production of sucrose and alanine radicals depended on both different particle irradiation and the LET under the same dose. Thus, the present ESR results imply that sucrose together with L-α-alanine can be used to monitor LET as well as the number of ionizing particle for the production of stable free radicals. (author)

  6. The effects of sucrose on the mechanical properties of acid milk proteins-kappa-carrageenan gels

    Directory of Open Access Journals (Sweden)

    E. Sabadini

    2006-03-01

    Full Text Available Mechanical properties have been widely correlated with textural characteristics to determine the interactions during the process formation of dairy gel. These interactions are strongly affected by process conditions and system composition. In the present study, the rheological of acid-induced protein dairy gels with (2(7-3 and without (2(6-2 sucrose and subjected to small and large deformations were studied using an experimental design. The independent variables were the sodium caseinate, whey protein concentrate (WPC, carrageenan and sucrose concentrations as well as stirring speed and heat treatment time and temperature. Mechanical deformation tests were performed at 0.1, 1, 5, and 9 mm/s up to 80% of initial height. A heavy dependence of rupture stress on increasing crosshead speed and the formation of harder gels with the addition of sucrose were observed. Moreover the elastic and viscous moduli, obtained by fitting the Maxwell model to stress relaxation data, increased with increasing addition of sucrose. These results can be explained by preferential hydration of the casein with sucrose, causing an induction of casein-polysaccharide and casein-casein interactions.

  7. Resurgence of Sucrose and Cocaine Seeking in Free-Feeding Rats

    Science.gov (United States)

    Shahan, Timothy A.; Craig, Andrew R.; Sweeney, Mary M.

    2014-01-01

    Resurgence is relapse of an extinguished operant response following the removal of alternative reinforcement. In animal models of resurgence to date, rats have been food deprived and food is used as the source of alternative reinforcement. Thus, when the alternative reinforcer is removed, the only remaining source of food during experimental sessions is no longer available. Acute food deprivation is known to produce reinstatement of drug seeking, thus such deprivation has been suggested a potential mechanism of resurgence. The present experiments examined whether resurgence of sucrose and cocaine seeking could be obtained with rats that were not food deprived. Free feeding rats were trained to press a lever for either sucrose (Exp 1) or cocaine infusions (Exp 2). Next, lever pressing was extinguished and an alternative response (nose poking) was reinforced with sucrose. When nose poking was also placed on extinction, resurgence of both sucrose and cocaine seeking were observed. Thus, resurgence of both sucrose and cocaine seeking can be obtained in rats that are not food restricted and it appears unlikely that an acute hunger state is responsible for resurgence. In addition, the present procedures for studying resurgence in the absence of interpretive complexities introduced by the use of food-deprivation may prove useful for further investigations of the neurobiological mechanisms of resurgence. PMID:25446761

  8. Antisense repression of sucrose phosphate synthase in transgenic muskmelon alters plant growth and fruit development

    International Nuclear Information System (INIS)

    To unravel the roles of sucrose phosphate synthase (SPS) in muskmelon (Cucumis melo L.), we reduced its activity in transgenic muskmelon plants by an antisense approach. For this purpose, an 830 bp cDNA fragment of muskmelon sucrose phosphate synthase was expressed in antisense orientation behind the 35S promoter of the cauliflower mosaic virus. The phenotype of the antisense plants clearly differed from that of control plants. The transgenic plant leaves were markedly smaller, and the plant height and stem diameter were obviously shorter and thinner. Transmission electron microscope observation revealed that the membrane degradation of chloroplast happened in transgenic leaves and the numbers of grana and grana lamella in the chloroplast were significantly less, suggesting that the slow growth and weaker phenotype of transgenic plants may be due to the damage of the chloroplast ultrastructure, which in turn results in the decrease of the net photosynthetic rate. The sucrose concentration and levels of sucrose phosphate synthase decreased in transgenic mature fruit, and the fruit size was smaller than the control fruit. Together, our results suggest that sucrose phosphate synthase may play an important role in regulating the muskmelon plant growth and fruit development.

  9. The ACR11 encodes a novel type of chloroplastic ACT domain repeat protein that is coordinately expressed with GLN2 in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Hsu Chih-Ping

    2011-08-01

    Full Text Available Abstract Background The ACT domain, named after bacterial aspartate kinase, chorismate mutase and TyrA (prephenate dehydrogenase, is a regulatory domain that serves as an amino acid-binding site in feedback-regulated amino acid metabolic enzymes. We have previously identified a novel type of ACT domain-containing protein family, the ACT domain repeat (ACR protein family, in Arabidopsis. Members of the ACR family, ACR1 to ACR8, contain four copies of the ACT domain that extend throughout the entire polypeptide. Here, we describe the identification of four novel ACT domain-containing proteins, namely ACR9 to ACR12, in Arabidopsis. The ACR9 and ACR10 proteins contain three copies of the ACT domain, whereas the ACR11 and ACR12 proteins have a putative transit peptide followed by two copies of the ACT domain. The functions of these plant ACR proteins are largely unknown. Results The ACR11 and ACR12 proteins are predicted to target to chloroplasts. We used protoplast transient expression assay to demonstrate that the Arabidopsis ACR11- and ACR12-green fluorescent fusion proteins are localized to the chloroplast. Analysis of an ACR11 promoter-β-glucuronidase (GUS fusion in transgenic Arabidopsis revealed that the GUS activity was mainly detected in mature leaves and sepals. Interestingly, coexpression analysis revealed that the GLN2, which encodes a chloroplastic glutamine synthetase, has the highest mutual rank in the coexpressed gene network connected to ACR11. We used RNA gel blot analysis to confirm that the expression pattern of ACR11 is similar to that of GLN2 in various organs from 6-week-old Arabidopsis. Moreover, the expression of ACR11 and GLN2 is highly co-regulated by sucrose and light/dark treatments in 2-week-old Arabidopsis seedlings. Conclusions This study reports the identification of four novel ACT domain repeat proteins, ACR9 to ACR12, in Arabidopsis. The ACR11 and ACR12 proteins are localized to the chloroplast, and the expression

  10. Evaluation of the risk of fungal spoilage when substituting sucrose with commercial purified Stevia glycosides in sweetened bakery products.

    Science.gov (United States)

    Rodríguez, Alicia; Magan, Naresh; Medina, Angel

    2016-08-16

    The objectives of this study were to compare the effect of different Stevia-based sugar substitutes (S1-S3), sucrose alone and a mixture of sucrose+S1 on: (a) humectant properties, (b) relative colonisation rates of sponge cake slices at 0.90 aw by strains of Aspergillus flavus, Eurotium amstelodami, Fusarium graminearum and Penicillium verrucosum at 20 and 25°C and (c) shelf-life periods in days prior to visible growth. Results showed that sucrose, S1 commercial sugar substitute and the mixture of sucrose+S1 in water solutions were able to reach water activity levels similar to those of glycerol and glucose mixtures. The S2 and S3 commercial sugar substitutes were unable to reduce aw levels significantly. At 25°C, colonisation of sponge cake slices by E. amstelodami, A. flavus and P. verrucosum occurred in all the treatments. Growth of F. graminearum only occurred on sponge cake slices containing S2 and S3 Stevia-based products at both temperatures. The best control of growth (30days) was achieved in cake slices modified with sucrose or S1 Stevia treatments inoculated with A. flavus and in the sucrose treatment for E. amstelodami at 20°C. F. graminearum growth was completely inhibited when sucrose alone, S1 or sucrose+S1 treatments were used at both temperatures. This study suggests that, as part of a hurdle technology approach, replacing sucrose with low calorie sugar substitutes based on Stevia glycosides needs to be done with care. This is because different products may have variable humectant properties and bulking agents which may shorten the potential shelf-life of intermediate moisture bakery products. PMID:27183230

  11. Avocado Oil Supplementation Modifies Cardiovascular Risk Profile Markers in a Rat Model of Sucrose-Induced Metabolic Changes

    OpenAIRE

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

    2014-01-01

    The purpose of this study was to evaluate the effects of avocado oil administration on biochemical markers of cardiovascular risk profile in rats with metabolic changes induced by sucrose ingestion. Twenty-five rats were divided into five groups: a control group (CG; basic diet), a sick group (MC; basic diet plus 30% sucrose solution), and three other groups (MCao, MCac, and MCas; basic diet plus 30% sucrose solution plus olive oil and avocado oil extracted by centrifugation or using solvent,...

  12. Effect of Sucrose Intake and Growth Conditions on Numbers of Dental Plaque Bacteria Expressing Pro teolytic Activity

    OpenAIRE

    Mikkelsen, L

    2011-01-01

    Proteolytic enzymes in dental plaque are important elements in the pathophysiology of periodontal disease and are putative virulence factors. The effect of sucrose intake versus a sucrose-free diet (substituting glucose for sucrose) on numbers of isolates from early dental plaque expressing extracellular proteolytic enzymes able to hydrolyse gelatin and azocoll was studied. The bacteria were isolated from 0-3 d dental plaque formed on the buccal surface of a lower premolar in six subjects. A ...

  13. Advances in Arabidopsis research in China from 2006 to 2007

    Institute of Scientific and Technical Information of China (English)

    LIANG Yan; ZUO JianRu; YANG WeiCai

    2007-01-01

    @@ Arabidopsis thaliana, a model plant species, has a number of advantages over other plant species as an experimental organism due to many of its genetic and genomic features. The Chinese Arabidopsis community has made significant contributions to plant biology research in recent years[1,2]. In 2006, studies of plant biology in China received more attention than ever before, especially those pertaining to Arabidopsis research. Here we briefly summarize recent advances in Arabidopsis research in China.

  14. High irradiance can minimize the negative effect of exogenous sucrose on the photosynthetic capacity of in vitro grown coconut plantlets

    International Nuclear Information System (INIS)

    There is increasing evidence that the sucrose normally added to the culture medium affects negatively the photosynthetic capacity of plantlets. At the same time, however, sucrose cannot be eliminated from the medium, as it is required for normal in vitro growth. We argue that this is true only under the conventional light conditions of growth-rooms. In the present paper irradiance of growth-rooms was increased 10 times and although the sucrose-inhibitory effect was found at high sucrose concentrations, it was possible to grow coconut (Cocos nucifera L.) plantlets without sucrose. Those plantlets showed both high photosynthetic capacity and comparable in vitro growth to those grown with sucrose in the medium under conventional growth-room irradiance. Nevertheless, the best growth was achieved under mixotrophic conditions where at high irradiance and moderate sucrose concentrations plantlets accumulated 27 % more biomass than plantlets grown without sucrose under high irradiance and 43 and 73 % more biomass than their counterparts at low irradiance with or without sucrose, respectively

  15. Influence of Sucrose Intake on Saliva and Number of Microorganisms and Acidogenic Potential in Early Dental Plaque

    OpenAIRE

    Mikkelsen, L

    2011-01-01

    The effect of sucrose intake versus a sucrose-free diet containing glucose on microscopic and viable counts of microorganisms in 0-3 d dental plaque formed on the buccal surface of a lower premolar was studied in six subjects. The acidogenic potential of 7 d dental plaque, as well as secretion rate, buffer capacity and pH of stimulated saliva, were estimated. Direct counts of microorganisms were higher in 2 and 3 d plaque formed on a sucrose-containing diet compared to plaque on a sucrose-fre...

  16. Sucrose as double-signal high-dose dosimeter for ionizing radiation

    International Nuclear Information System (INIS)

    A possibility to use chemically pure sucrose as double-signal (EPR+UV) dosimeter for high doses of gamma radiation was checked. Sucrose (as obtained) was irradiated in solid state and one part of the sample was analyzed by EPR and the second one by optical method. In a range 5-50 kGy both signals were linearly dependent on an absorbed dose. Additionally, a linear correlation between EPR and optical signal was observed. EPR signal (peak-to-peak amplitude) decreased slowly with time (some percent during the first 11 weeks). The decay was slightly dose depended. Optical signals were measured after dissolution of irradiated sucrose in triple distilled water. An absorption band with maximum at 263 nm was chosen as dosimetric signal. Its intensity increased slowly with time (about 5% during the first day). The heating procedure proposed in literature for UV signal stabilization was checked but it was not recommended for a routine use.

  17. Optimal Control for Industrial Sucrose Crystallization with Action Dependent Heuristic Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Xiaofeng Lin

    2009-10-01

    Full Text Available This paper applies a neural-network-based approximate dynamic programming (ADP method, namely, the action dependent heuristic dynamic programming (ADHDP, to an industrial sucrose crystallization optimal control problem. The industrial sucrose crystallization is a nonlinear and slow time-varying process. It is quite difficult to establish a precise mechanism model of the crystallization, because of complex internal mechanism and interacting variables. We developed a neural network model of the crystallization based on the data from the actual sugar boiling process of sugar refinery. The ADHDP is a learningand approximation-based approach which can solve the optimization control problem of nonlinear system. The paper covers the basic principle of this learning scheme and the design of neural network controller based on the approach. The result of simulation shows the controller based on action dependent heuristic dynamic programming approach can optimize industrial sucrose crystallization.

  18. Solid-phase radioimmunoassay of immunoglobulins G, A and M: applicability in analysis of sucrose gradients

    Energy Technology Data Exchange (ETDEWEB)

    Eriksen, E.F.; Danielsen, H. (Aarhus Kommunehospital (Denmark). Medical Department C); Johansen, A.S. (Aarhus Univ. (Denmark). Institute of Medical Biochemistry); Larsson, L.I. (Unit of Histochemistry, University Institute of Pathology, Copenhagen, Denmark)

    1984-01-01

    A simple and sensitive solid-phase radioimmunoassay for the detection of immunoglobulins G, A and M in sucrose gradients is described. The solid-phase consisted of immunoglobulins adsorbed to polystyrene tubes. Using buffers without detergent and /sup 125/I-labeled sheep anti-rabbit IgA as radioligand, the assay was able to detect 0.8 ng per tube in the IgG assay and 1.6 ng per tube in the IgA and IgM assays. Standard curves with antigen dissolved in 10% and 32% sucrose were superimposable and did not deviate from standard curves with antigen dissolved in buffer without sucrose. Using these techniques on ultracentrifugation samples from patients with systemic lupus erythematosus, Schoenlein-Henoch nephritis and IgA glorulonephritis is was possible to detect both immunoglobulin fragments and immunoglobulin aggregates at the same time without prior dialysis of the samples.

  19. The effect of viscosity on the HO2 uptake by sucrose and secondary organic aerosol particles

    OpenAIRE

    Lakey, Pascale S. J.; Berkemeier, Thomas; Krapf, Manuel; Dommen, Josef; Steimer, Sarah S.; Whalley, Lisa K.; Ingham, Trevor; Baeza-Romero, Maria T.; Pöschl, Ulrich; Shiraiwa, Manabu; Ammann, Markus; Heard, Dwayne E.

    2016-01-01

    We report the first measurements of HO2 uptake coefficients, γ, for secondary organic aerosol particles (SOA) and for the well-studied model compound sucrose which was doped with copper. Above 65 % relative humidity (RH), γ for copper doped sucrose aerosol particles equalled the surface mass accommodation coefficient α = 0.22 ± 0.06 but decreased to γ = 0.012 ± 0.007 upon decreasing the RH to 17 %. The trend of γ with RH can be explained by an increase in aerosol viscosity, as demonstra...

  20. Membrane association of sucrose synthase: changes during the graviresponse and possible control by protein phosphorylation

    Science.gov (United States)

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

    1997-01-01

    Sucrose synthase (SuSy) plays an important role in sucrose degradation and occurs both as a soluble and as a membrane-associated enzyme in higher plants. We show that membrane association can vary in vivo in response to gravistimulation, apparently involving SuSy dephosphorylation, and is a reversible process in vitro. Phosphorylation of SuSy has little effect on its activity but decreases its surface hydrophobicity as reported with the fluorescent probe bis-ANS. We postulate that phosphorylation of SuSy (and perhaps other membrane proteins) is involved in the release of the membrane-bound enzyme in part as a result of decreased surface hydrophobicity.

  1. Time dependence of the radiation-induced EPR signal in sucrose

    International Nuclear Information System (INIS)

    Sucrose and common household sugars (e.g. cane) have been studied as dosemeters for a wide variety of applications. However, previous studies of the post-irradiation time dependence of irradiated sugar did not include an electron paramagnetic resonance (EPR) reference material. This work employs synthetic ruby as an EPR reference material to remove significant spectrometer/environmental influences on the measured time-dependent changes in the EPR spectral amplitude of irradiated sucrose. As such, these more accurate measurements should replace the previously published data. (authors)

  2. A cDNA clone from Zea mays endosperm sucrose synthetase mRNA.

    OpenAIRE

    Geiser, M.; Döring, H P; Wöstemeyer, J; Behrens, U.; Tillmann, E; Starlinger, P.

    1980-01-01

    A cDNA clone for maize endosperm sucrose synthetase of 62o nucleotide pairs length was obtained by cloning double stranded DNA obtained from the total maize endosperm poly(A) RNA in pBR322, and identifying the appropriate clone by hybrid-promoter translation. In Southern blotting to genomic BamHI-digested DNA, a single band only of approximately 20 Kb lights up, indicating that the sucrose synthetase gene is unique, or that closely linked copies are located on this DNA fragment.

  3. Pontine and Thalamic Influences on Fluid Rewards: II. Sucrose and Corn Oil Conditioned Aversions

    OpenAIRE

    Liang, Nu-Chu; Grigson, Patricia S.; Norgren, Ralph

    2011-01-01

    In this study conditioned aversions were produced in sham feeding rats to limit postingestive feedback from the oral stimulus. All control rats learned an aversion to either 100% corn oil or 0.3M sucrose when ingestion of these stimuli was followed by an injection of lithium chloride (LiCl). Rats with lesions of the ventroposteromedial thalamus also learned to avoid either corn oil or sucrose. After 3 trials, rats with damage to the parabrachial nuclei (PBN) learned to avoid 100% corn oil, bu...

  4. Mortality of Bemisia tabaci biotype B (sternorrhyncha: aleyrodidae adults by aliphatic and aromatic synthetic sucrose esters

    Directory of Open Access Journals (Sweden)

    Mariangela Alves

    2008-12-01

    Full Text Available The B-strain of Bemisia tabaci Gennadius is a key pest of several crops and chemical control is the main control method used by growers, although reduction in efficacy due to insecticide resistance has already been reported. The aim of this work was to investigate the insecticidal effect of an array of synthetic sucrose esters with the aliphatic and aromatic groups on whitefly adults. Sucrose butyrate, caprate, octanoate, palmitate, oleate, octaacetate, phthalate, benzoate, and sucrose diacetate hexaisobutyrate were tested. The solutions were prepared and applied on the adults caught on yellow sticky traps using the Potter spray tower. Long-chains sucrose aliphatic esters were more effective against the silverleaf whiteflies and the highest mortality was obtained with sucrose oleate and sucrose octanoate. Since these compounds were tensoactive, sodium dodecylsulphate was also tested for the comparison but no effect was observed. Sucrose butyrate and other aliphatic and aromatic sucrose polyesters showed negligible effect on the silverleaf whiteflies.O biótipo B de B. tabaci Gennadius tem se destacado como uma praga-chave de diversas culturas. O controle químico tem sido a principal tática de controle utilizada, embora já se tenha observado redução na eficiência dos produtos devido ao desenvolvimento de resistência. Assim, o objetivo do presente trabalho foi avaliar o efeito de diversos ésteres de sacarose com grupos alifáticos ou aromáticos sobre adultos de mosca-branca. Butirato de sacarose, caprato, octanoato, palmitato, oleato, actaacetato, ftlato, benzoato e diacetato hexaisobutirato de sacarose foram testados. Soluções de éster de sacarose foram preparadas e aplicadas sobre adultos capturados em armadilhas adesivas utilizando Torre de Potter. Ésteres alifáticos de sacarose com longas cadeias foram mais efetivos contra mosca-branca e as maiores taxas de mortalidade foram obtidas com oleato e octanoato de sacarose. Uma vez que

  5. Characterization of sucrose-negative Pasteurella multocida variants, including isolates from large-cat bite wounds

    DEFF Research Database (Denmark)

    Christensen, Henrik Grimmig; Bisgaard, Magne; Angen, Øystein; Frederiksen, Wilhelm; Olsen, John Elmerdal

    2005-01-01

    showed the monophyly of the strains characterized and the reference strains of P. multocida. The sucrose-negative strains formed two groups, one related to reference strains of P. multocida and the other related to a separate species-like group (taxon 45 of Bisgaard). DNA-DNA hybridization further...... reference strains of P. multocida. Two strains isolated from leopard bite wounds were related to the type strain of P. dagmatis; however, they represented a new taxon (taxon 46 of Bisgaard), in accordance with their distinct phenotypic and genotypic identifications. The present study documents that sucrose...

  6. Mining the active proteome of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Renier A. L. Van Der Hoorn

    2011-11-01

    Full Text Available Assigning functions to the >30.000 proteins encoded by the Arabidopsis genome is a challenging task of the Arabidopsis Functional Genomics Network. Although genome-wide technologies like proteomics and transcriptomics have generated a wealth of information that significantly accelerated gene annotation, protein activities are poorly predicted by transcript or protein levels as protein activities are post-translationally regulated. To directly display protein activities in Arabidopsis proteomes, we developed and applied Activity-based Protein Profiling (ABPP. ABPP is based on the use of small molecule probes that react with the catalytic residues of distinct protein classes in an activity-dependent manner. Labeled proteins are separated and detected from proteins gels and purified and identified by mass spectrometry. Using probes of six different chemotypes we have displayed of activities of 76 Arabidopsis proteins. These proteins represent over ten different protein classes that contain over 250 Arabidopsis proteins, including cysteine- serine- and metallo-proteases, lipases, acyltransferases, and the proteasome. We have developed methods for identification of in vivo labeled proteins using click-chemistry and for in vivo imaging with fluorescent probes. In vivo labeling has revealed novel protein activities and unexpected subcellular activities of the proteasome. Labeling of extracts displayed several differential activities e.g. of the proteasome during immune response and methylesterases during infection. These studies illustrate the power of ABPP to display the functional proteome and testify to a successful interdisciplinary collaboration involving chemical biology, organic chemistry and proteomics.

  7. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The environmental effects and bioavailability of nanoparticulate iron (Fe) to plants are currently unknown. Here, plant bioavailability of synthesized hematite Fe nanoparticles was evaluated using Arabidopsis thaliana (A. thaliana) as a model. Over 56-days of growing wild-type A. thaliana, the nanoparticle-Fe and no-Fe treatments had lower plant biomass, lower chlorophyll concentrations, and lower internal Fe concentrations than the Fe-treatment. Results for the no-Fe and nanoparticle-Fe treatments were consistently similar throughout the experiment. These results suggest that nanoparticles (mean diameter 40.9 nm, range 22.3–67.0 nm) were not taken up and therefore not bioavailable to A. thaliana. Over 14-days growing wild-type and transgenic (Type I/II proton pump overexpression) A. thaliana, the Type I plant grew more than the wild-type in the nanoparticle-Fe treatment, suggesting Type I plants cope better with Fe limitation; however, the nanoparticle-Fe and no-Fe treatments had similar growth for all plant types. -- Highlights: ► Iron nanoparticles were synthesized and assessed for bioavailability to Arabidopsis. ► Arabidopsis grew better in the presence of EDTA-bound iron than nanoparticulate iron. ► Arabidopsis grew the same in the presence of nanoparticulate iron compared to no iron. -- Synthesized iron nanoparticles were not bioavailable to Arabidopsis thaliana in agar nutrient media

  8. Sugars and light/dark exposure trigger differential regulation of ADP-glucose pyrophosphorylase genes in Arabidopsis thaliana (thale cress).

    Science.gov (United States)

    Sokolov, L N; Déjardin, A; Kleczkowski, L A

    1998-12-15

    Expression of four Arabidopsis (thale cress) genes corresponding to the small (ApS) and large subunits (ApL1, ApL2, ApL3) of ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch biosynthesis, was found to be profoundly and differentially regulated by sugar and light/dark exposures. Transcript levels of both ApL2 and ApL3, and to a lesser extent ApS, increased severalfold upon feeding sucrose or glucose to the detached leaves in the dark, whereas the mRNA content for ApL1 decreased under the same conditions. Glucose was, in general, less effective than sucrose in inducing regulation of AGPase genes, possibly due to observed limitations in its uptake when compared with sucrose uptake by detached leaves. Osmotic agents [sorbitol, poly(ethylene glycol)] had no effect on ApS, ApL2 and ApL3 transcript level, but they did mimic the effect of sucrose on ApL1 gene, suggesting that the latter is regulated by osmotic pressure rather than any particular sugar. For all the genes the sugar effect was closely mimicked by an exposure of the dark-pre-adapted leaves to the light. Under both dark and light conditions, sucrose fed to the detached leaves was found to be rapidly metabolized to hexoses and, to some extent, starch. Starch production reflected most probably an increase in substrate availability for AGPase reaction rather than being due to changes in AGPase protein content, since both the sugar feeding and light exposure had little or no effect on the activity of AGPase or on the levels of its small and large subunit proteins in leaf extracts. The data suggest tight translational or post-translational control, but they may also reflect spatial control of AGPase gene expression within a leaf. The sugar/light-dependent regulation of AGPase gene expression may represent a part of a general cellular response to the availability/allocation of carbohydrates during photosynthesis. PMID:9841881

  9. Recent Progress in Arabidopsis Research in China: A Preface

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hong Xu

    2006-01-01

    @@ In 2002, a workshop on Arabidopsis research in China was held in Shanghai, when a small group of Chinese plant scientists was working on this model species. Since then, we have witnessed the rapid growth of Arabidopsis research in China. This special issue of Journal of Integrative Plant Biology is dedicated exclusively to the Fourth Workshop on Arabidopsis Research in China, scheduled on November 30, 2005, in Beijing. In addition to reports collected in this special issue, the Chinese Arabidopsis community has been able to make significant contributions to many research fields. Here, I briefly summarize recent advances in Arabidopsis research in China.

  10. Arabidopsis CDS blastp result: AK072052 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK072052 J013111I10 At4g32770.1 tocopherol cyclase, chloroplast / vitamin ... E deficient 1 (VTE1) / ... |Q94FY7 Tocopherol cyclase, chloroplast precursor (Vitamin ... E deficient 1) (Sucrose export defective 1) {Arabi ...

  11. The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-05-11

    Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  12. The non-metabolizable sucrose analog sucralose is a potent inhibitor of hormogonium differentiation in the filamentous cyanobacterium Nostoc punctiforme.

    Science.gov (United States)

    Splitt, Samantha D; Risser, Douglas D

    2016-03-01

    Nostoc punctiforme is a filamentous cyanobacterium which forms nitrogen-fixing symbioses with several different plants and fungi. Establishment of these symbioses requires the formation of motile hormogonium filaments. Once infected, the plant partner is thought to supply a hormogonium-repressing factor (HRF) to maintain the cyanobacteria in a vegetative, nitrogen-fixing state. Evidence implies that sucrose may serve as a HRF. Here, we tested the effects of sucralose, a non-metabolizable sucrose analog, on hormogonium differentiation. Sucralose inhibited hormogonium differentiation at a concentration approximately one-tenth that of sucrose. This result implies that: (1) sucrose, not a sucrose catabolite, is perceived by the cell and (2) inhibition is not due to a more general osmolarity-dependent effect. Additionally, both sucrose and sucralose induced the accrual of a polysaccharide sheath which bound specifically to the lectin ConA, indicating the presence of α-D-mannose and/or α-D-glucose. A ConA-specific polysaccharide was also found to be expressed in N. punctiforme colonies from tissue sections of the symbiotically grown hornwort Anthoceros punctatus. These findings imply that plant-derived sucrose or sucrose analogs may have multiple effects on N. punctiforme, including both repression of hormogonia and the induction of a polysaccharide sheath that may be essential to establish and maintain the symbiotic state. PMID:26576759

  13. Induction when Rats Respond for Liquid-Sucrose Reinforcement as a Function of Amount of Upcoming "Work"

    Science.gov (United States)

    Weatherly, Jeffrey N.; Bauste, Grant A.; McDougall, Casey L.; Nurnberger, Jeri T.

    2006-01-01

    Previous research has shown that rats increase their rate of responding for 1% sucrose reinforcement in the first half of the session if food-pellet, rather than 1% sucrose, reinforcement will be available in the second half (i.e., positive induction). Four experiments investigated whether this induction effect would be changed by altering the…

  14. Fumaric acid: an overlooked form of fixed carbon in Arabidopsis and other plant species

    Energy Technology Data Exchange (ETDEWEB)

    Chia, D.W.; Yoder, T.J.; Reiter, W.D.; Gibson, S.I.

    2000-10-01

    Photoassimilates are used by plants for production of energy, as carbon skeletons and in transport of fixed carbon between different plant organs. Many studies have been devoted to characterizing the factors that. regulate photoassimilate concentrations in different plant species. Most studies examining photoassimilate concentrations in C{sub 3} plants have focused on analyzing starch and soluble sugars. However, work presented here demonstrates that a number of C{sub 3} plants, including the popular model organism Arabidopsis thaliana (L.) Heynh., and agriculturally important plants, such as soybean [Glycine ma (L.) Merr.], contain significant quantities of furnaric acid. In fact, furnaric acid can accumulate to levels of several mg per g fresh weight in A-abidopsis leaves, often exceeding starch and soluble sugar levels. Furnaric acid is a component of the tricarboxylic acid cycle and, like starch and soluble sugars, can be metabolized to yield energy and carbon skeletons for production of other compounds. Fumaric acid concentrations increase with plant age and light intensity in Arabidopsis leaves. Arabidopsis phloem exudates contain significant quantities of fumaric acid, raising the possibility that fumaric acid may function in carbon transport.

  15. The better growth phenotype of DvGS1-transgenic arabidopsis thaliana is attributed to the improved efficiency of nitrogen assimilation

    Directory of Open Access Journals (Sweden)

    Zhu Chenguang

    2015-01-01

    Full Text Available The overexpression of the algal glutamine synthetase (GS gene DvGS1 in Arabidopsis thaliana resulted in higher plant biomass and better growth phenotype. The purpose of this study was to recognize the biological mechanism for the growth improvement of DvGS1-transgenic Arabidopsis. A series of molecular and biochemical investigations related to nitrogen and carbon metabolism in the DvGS1-transgenic line was conducted. Analysis of nitrogen use efficiency (NUE-related gene transcription and enzymatic activity revealed that the transcriptional level and enzymatic activity of the genes encoding GS, glutamate synthase, glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase, were significantly upregulated, especially from leaf tissues of the DvGS1-transgenic line under two nitrate conditions. The DvGS1-transgenic line showed increased total nitrogen content and decreased carbon: nitrogen ratio compared to wild-type plants. Significant reduced concentrations of free nitrate, ammonium, sucrose, glucose and starch, together with higher concentrations of total amino acids, individual amino acids (glutamate, aspartate, asparagine, methionine, soluble proteins and fructose in leaf tissues confirmed that the DvGS1-transgenic line demonstrated a higher efficiency of nitrogen assimilation, which subsequently affected carbon metabolism. These improved metabolisms of nitrogen and carbon conferred the DvGS1-transgenic Arabidopsis higher NUE, more biomass and better growth phenotype compared with the wild-type plants.

  16. Arabidopsis CDS blastp result: AK243152 [KOME

    Lifescience Database Archive (English)

    Full Text Available ase PP1 isozyme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains...P1 isozyme 4 (TOPP4) / phosphoprotein phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphat... a Ser/Thr protein phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 1e-154 ... ...AK243152 J100032N02 At2g39840.1 68415.m04893 serine/threonine protein phosphatase P

  17. Arabidopsis CDS blastp result: AK288069 [KOME

    Lifescience Database Archive (English)

    Full Text Available ase PP1 isozyme 4 (EC 3.1.3.16) {Arabidopsis thaliana}, phosphoprotein phosphatase 1 GI:166801 (Arabidopsis thaliana); contains...P1 isozyme 4 (TOPP4) / phosphoprotein phosphatase 1 identical to SP|P48484 Serine/threonine protein phosphat... a Ser/Thr protein phosphatase signature (PDOC00115); contains a metallo-phosphoesterase motif (QDOC50185) 6e-70 ... ...AK288069 J075158N05 At2g39840.1 68415.m04893 serine/threonine protein phosphatase P

  18. Gibberellins control fruit patterning in Arabidopsis thaliana.

    Science.gov (United States)

    Arnaud, Nicolas; Girin, Thomas; Sorefan, Karim; Fuentes, Sara; Wood, Thomas A; Lawrenson, Tom; Sablowski, Robert; Østergaard, Lars

    2010-10-01

    The Arabidopsis basic helix-loop-helix (bHLH) proteins INDEHISCENT (IND) and ALCATRAZ (ALC) specify tissues required for fruit opening that have major roles in seed dispersal and plant domestication. Here, we show that synthesis of the phytohormone gibberellin is a direct and necessary target of IND, and that ALC interacts directly with DELLA repressors, which antagonize ALC function but are destabilized by gibberellin. Thus, the gibberellin/DELLA pathway has a key role in patterning the Arabidopsis fruit, and the interaction between DELLA and bHLH proteins, previously shown to connect gibberellin and light responses, is a versatile regulatory module also used in tissue patterning. PMID:20889713

  19. Effect of Potassium and Sucrose Concentrations on the Production of Potato Micro tubers Through Tissue Culture

    International Nuclear Information System (INIS)

    This investigation was carried out on potato (Solanum tuberosum) cultivar Alphawhere shoot tips were cultured on solid MS medium supplemented with 3% sucrose and 1 mg/ l of BA for four weeks. Multi nodal (three nodes) explants were excised from proliferated shoots and were subcultured on MS media with different strengths (25, 50 and 75 % strength of MS medium) enriched with potassium nitrate (at concentrations of 475, 950, 1425 and 1900 mg/ l), potassium di-hydrogen-ortho-phosphate (at concentrations of 42.5, 85.0, 127.5 and 170 mg/ l), and sucrose (at concentrations 25, 50, 75 and 100 g/ l) to produce micro tubers under long day (LD) and dark conditions on growth- regulator- free mediums. The results indicated that maximum number of micro tubers was produced on MS medium with 25% strength supplemented with 25 g/ l sucrose under LD conditions, whereas under dark conditions, best results were obtained from cultures on 75% strength MS mediums enriched with 950 and 1425 mg/ l KNO3. It was also found that regardless of MS medium strength, sucrose additives resulted in the production of micro tubers with the heaviest weights under LD conditions, while under dark conditions, all potassium supplements produced relatively heavy micro tubers. Finally, MS medium with 25 % strength supplemented with 170 / l KH2PO4 produced the largest micro tubers under LD conditions, while 75 % MS medium with supplemented with 127.5 g/ l KH2PO4 under dark conditions produced the largest micro tubers.

  20. Autophagic sequestration of [14C]sucrose, introduced into rat hepatocytes by reversible electro-permeabilization

    International Nuclear Information System (INIS)

    Isolated rat hepatocytes could be made permeable to small molecules such as [14C]sucrose (but not to proteins) but subjecting the cells to repeated discharges in a high-voltage field. During subsequent incubation at 370C, the permeability changes were reversed within 15 min, the electron-injected [14C]sucros remaining trapped inside the re-sealed plasma membrane. Autophagic sequestration of [14C]sucrose, i.e., the transfer of radioactivity from cytosol to sedimentable vesicles (autophagosomes and lysosomes), could be followed by incubating the [14C]sucrose-loaded hepatocytes for up to 2 h at 370C. After incubation, the cells were disrupted by a single high-voltage discharge in electrolyte-free medium (sucrose), and sedimentable cell components were separated from the cytosol by centrifugation through metrizamide. By the use of these methods, which are particularly suitable for the analysis of many small cell samples, it could be shown that [14C]sucros was autophagically sequestered in the hepatocytes at a rate of 4-5%/h. The sequestration was nearly completely inhibited by the specific autophagy inhibitor 3-methyladenine