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Sample records for acid uptake systems

  1. Bulk, surface properties and water uptake mechanisms of salt/acid amorphous composite systems.

    PubMed

    Bianco, Stefano; Tewes, Frederic; Tajber, Lidia; Caron, Vincent; Corrigan, Owen I; Healy, Anne Marie

    2013-11-01

    Developing amorphous pharmaceuticals can be desirable due to advantageous biopharmaceutical properties. Low glass transition temperature (Tg) amorphous drugs can be protected from crystallisation by mixing with high Tg excipients, such as polymers, or with salt forms. However, both polymers and salts can enhance the water uptake. The aim of this study was to formulate physico-chemically stable amorphous materials, by co-processing different proportions of sulfathiazole and its sodium salt to produce an optimum ratio, characterised by the best physical stability and lowest hygroscopicity. Both sulfathiazole and salt amorphised upon spray drying. At room temperature, sulfathiazole crystallised within 1h at <5% relative humidity while the salt deliquesced when exposed to ambient humidity conditions. In the case of composite systems, FTIR spectroscopy, thermal and surface analysis suggested interactions with an acid:salt stoichiometry of 1:2. Increasing proportions of salt raised the Tg, enhancing the storage stability, however this was opposed by an enhanced hygroscopicity. The water uptake mechanism within the different amorphous systems, analysed by fitting the water sorption isotherms with the Young and Nelson equation, was dependent on the ratio employed, with the salt and the acid facilitating absorption and adsorption, respectively. Tuning the properties of amorphous salt/acid composites by optimising the ratio appears potentially promising to improve the physical stability of amorphous formulations. PMID:23948137

  2. Effect of antisense oligonucleotides on the expression of hepatocellular bile acid and organic anion uptake systems in Xenopus laevis oocytes.

    PubMed Central

    Hagenbuch, B; Scharschmidt, B F; Meier, P J

    1996-01-01

    A Na(+)-dependent bile acid (Na+/taurocholate co-transporting polypeptide; Ntcp) and a Na(+)-independent bromosulphophthalein (BSP)/bile acid uptake system (organic-anion-transporting polypeptide; oatp) have been cloned from rat liver by using functional expression cloning in Xenopus laevis oocytes. To evaluate the extent to which these cloned transporters could account for overall hepatic bile acid and BSP uptake, we used antisense oligonucleotides to inhibit the expression of Ntcp and oatp in Xenopus laevis oocytes injected with total rat liver mRNA. An Ntcp-specific antisense oligonucleotide co-injected with total rat liver mRNA blocked the expression of Na(+)-dependent taurocholate uptake by approx. 95%. In contrast, an oatp-specific antisense oligonucleotide when co-injected with total rat liver mRNA had no effect on the expression of Na(+)-dependent taurocholate uptake, but it blocked Na(+)-independent uptake of taurocholate by approx. 80% and of BSP by 50%. Assuming similar expression of hepatocellular bile acid and organic anion transporters in Xenopus laevis oocytes, these results indicate that Ntcp and oatp respectively represent the major, if not the only, Na(+)-dependent and Na(+)-independent taurocholate uptake systems in rat liver. By contrast, the cloned oatp accounts for only half of BSP transport, suggesting that there must be additional, non-bile acid transporting organic anion uptake systems in rat liver. PMID:8670169

  3. Transport of coenzyme M (2-mercaptoethanesulfonic acid) and methylcoenzyme M [(2-methylthio)ethanesulfonic acid] in Methanococcus voltae: identification of specific and general uptake systems.

    PubMed Central

    Dybas, M; Konisky, J

    1989-01-01

    A transport system for coenzyme M (2-mercaptoethanesulfonic acid [HS-CoM]) and methylcoenzyme M [(2-(methylthio)ethanesulfonic acid (CH3-S-CoM)] in Methanococcus voltae required energy, showed saturation kinetics, and concentrated both forms of coenzyme M against a concentration gradient. Transport required hydrogen and carbon dioxide for maximal uptake. CH3-S-CoM uptake was inhibited by N-ethylmaleimide and monensin. Both HS-CoM and CH3-S-CoM uptake showed sodium dependence. In wild-type M. voltae, HS-CoM uptake was concentration dependent, with a Vmax of 960 pmol/min per mg of protein and an apparent Km of 61 microM. Uptake of CH3-S-CoM showed a Vmax of 88 pmol/min per mg of protein and a Km of 53 microM. A mutant of M. voltae resistant to the coenzyme M analog 2-bromoethanesulfonic acid (BES) showed no uptake of CH3-S-CoM but accumulated HS-CoM at the wild-type rate. While the higher-affinity uptake system was specific for HS-CoM, the lower-affinity system mediated uptake of HS-CoM, CH3-S-CoM, and BES. Analysis of the intracellular coenzyme M pools in metabolizing cells showed an intracellular HS-CoM concentration of 14.8 mM and CH3-S-CoM concentration of 0.21 mM. PMID:2509421

  4. Glycinergic-Fipronil Uptake Is Mediated by an Amino Acid Carrier System and Induces the Expression of Amino Acid Transporter Genes in Ricinus communis Seedlings.

    PubMed

    Xie, Yun; Zhao, Jun-Long; Wang, Chuan-Wei; Yu, Ai-Xin; Liu, Niu; Chen, Li; Lin, Fei; Xu, Han-Hong

    2016-05-18

    Phloem-mobile insecticides are efficient for piercing and sucking insect control. Introduction of sugar or amino acid groups to the parent compound can improve the phloem mobility of insecticides, so a glycinergic-fipronil conjugate (GlyF), 2-(3-(3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)sulfinyl)-1H-pyrazole-5-yl)ureido) acetic acid, was designed and synthesized. Although the "Kleier model" predicted that this conjugate is not phloem mobile, GlyF can be continually detected during a 5 h collection of Ricinus communis phloem sap. Furthermore, an R. communis seedling cotyledon disk uptake experiment demonstrates that the uptake of GlyF is sensitive to pH, carbonyl cyanide m-chlorophenylhydrazone (CCCP), temperature, and p-chloromercuribenzenesulfonic acid (pCMBS) and is likely mediated by amino acid carrier system. To explore the roles of amino acid transporters (AATs) in GlyF uptake, a total of 62 AAT genes were identified from the R. communis genome in silico. Phylogenetic analysis revealed that AATs in R. communis were organized into the ATF (amino acid transporter) and APC (amino acid, polyaminem and choline transporter) superfamilies, with five subfamilies in ATF and two in APC. Furthermore, the expression profiles of 20 abundantly expressed AATs (cycle threshold (Ct) values <27) were analyzed at 1, 3, and 6 h after GlyF treatment by RT-qPCR. The results demonstrated that expression levels of four AAT genes, RcLHT6, RcANT15, RcProT2, and RcCAT2, were induced by the GlyF treatment in R. communis seedlings. On the basis of the observation that the expression profile of the four candidate genes is similar to the time course observation for GlyF foliar disk uptake, it is suggested that those four genes are possible candidates involved in the uptake of GlyF. These results contribute to a better understanding of the mechanism of GlyF uptake as well as phloem loading from a molecular biology perspective and facilitate functional

  5. Post-uptake metabolism affects quantification of amino acid uptake.

    PubMed

    Warren, Charles R

    2012-01-01

    • The quantitative significance of amino acids to plant nutrition remains controversial. This experiment determined whether post-uptake metabolism and root to shoot export differ between glycine and glutamine, and examined implications for estimation of amino acid uptake. • Field soil containing a Eucalyptus pauciflora seedling was injected with uniformly (13)C- and (15)N-labelled glycine or glutamine. I quantified (15)N and (13)C excess in leaves and roots and intact labelled amino acids in leaves, roots and stem xylem sap. A tunable diode laser quantified fluxes of (12)CO(2) and (13)CO(2) from leaves and soil. • 60-360 min after addition of amino acid, intact molecules of U-(13)C,(15)N glutamine were < 5% of (15)N excess in roots, whereas U-(13)C,(15)N glycine was 30-100% of (15)N excess in roots. Intact molecules of glutamine, but not glycine, were exported from roots to shoots. • Post-uptake metabolism and transport complicate interpretation of isotope labelling such that root and shoot contents of intact amino acid, (13)C and (15)N may not reflect rates of uptake. Future experiments should focus on reconciling discrepancies between intact amino acid, (13)C and (15)N by determining the turnover of amino acids within roots. Alternatively, post-uptake metabolism and transport could be minimized by harvesting plants within minutes of isotope addition.

  6. Electrogenicity of hepatocellular fatty acid uptake.

    PubMed

    Elsing, C; Kassner, A; Gajdzik, L; Graf, J; Stremmel, W

    1998-08-18

    Sensitivity of cellular fatty acids uptake to the membrane potential difference is still a matter of controversy. For direct evaluation of potential sensitivity the effect of changing membrane potential on uptake of a fluorescent long chain fatty acid derivative, 12-NBD-stearate, in isolated rat hepatocytes, was examined. Changes in membrane potential were achieved by patch clamp procedures. Fatty acid influx was simultaneously determined by recording of cell fluorescence. Hyperpolarization from -30 to -70 mV accelerated fatty acid influx whereas depolarization to +50 mV reduced uptake. After obtaining equilibrium hyperpolarization increased cell fluorescence, whereas depolarization pushed NBD-stearate out of cells. Potential sensitivity of uptake was dependent on the fatty acid concentrations in the medium with most prominent effects at low unbound concentrations. These data show that, at low fatty acid concentrations, uptake is, in part, driven by an intracellular negative electric membrane potential.

  7. Uptake of sialic acid by human erythrocyte. Characterization of a transport system.

    PubMed

    Bulai, Tatiana; Bratosin, Daniela; Artenie, Vlad; Montreuil, Jean

    2003-01-01

    Upon incubation of human red blood cells (RBC) with [4-9-14C] N-acetylneuraminic acid, the cells incorporated this sugar, as demonstrated by the identification of labelled N-acetylmannosamine in the cytosol, as a result of the action of the sialic acid pyruvate-lyase we discovered previously (Biochimie 84 (2002) 655). The mechanism is saturable and indicates the presence of a limited number of transporter molecules in the RBC membrane. This transport process may have relevance to the desialylation of membrane glycoconjugates which occurs during ageing of erythrocytes.

  8. Uptake, efficacy, and systemic distribution of naked, inhaled short interfering RNA (siRNA) and locked nucleic acid (LNA) antisense.

    PubMed

    Moschos, Sterghios A; Frick, Manfred; Taylor, Bruce; Turnpenny, Paul; Graves, Helen; Spink, Karen G; Brady, Kevin; Lamb, David; Collins, David; Rockel, Thomas D; Weber, Markus; Lazari, Ovadia; Perez-Tosar, Luis; Fancy, Sally A; Lapthorn, Chris; Green, Martin X; Evans, Steve; Selby, Matthew; Jones, Gareth; Jones, Lyn; Kearney, Sarah; Mechiche, Houria; Gikunju, Diana; Subramanian, Romesh; Uhlmann, Eugen; Jurk, Marion; Vollmer, Jörg; Ciaramella, Giuseppe; Yeadon, Michael

    2011-12-01

    Antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) promise specific correction of disease-causing gene expression. Therapeutic implementation, however, has been forestalled by poor delivery to the appropriate tissue, cell type, and subcellular compartment. Topical administration is considered to circumvent these issues. The availability of inhalation devices and unmet medical need in lung disease has focused efforts in this tissue. We report the development of a novel cell sorting method for quantitative, cell type-specific analysis of siRNA, and locked nucleic acid (LNA) ASO uptake and efficacy after intratracheal (i.t.) administration in mice. Through fluorescent dye labeling, we compare the utility of this approach to whole animal and whole tissue analysis, and examine the extent of tissue distribution. We detail rapid systemic access and renal clearance for both therapeutic classes and lack of efficacy at the protein level in lung macrophages, epithelia, or other cell types. We nevertheless observe efficient redirection of i.t. administered phosphorothioate (PS) LNA ASO to the liver and kidney leading to targeted gene knockdown. These data suggest delivery remains a key obstacle to topically administered, naked oligonucleotide efficacy in the lung and introduce inhalation as a potentially viable alternative to injection for antisense administration to the liver and kidneys.

  9. Identification and Characterization of γ-Aminobutyric Acid Uptake System GabPCg (NCgl0464) in Corynebacterium glutamicum

    PubMed Central

    Zhao, Zhi; Ma, Wen-hua; Zhou, Ning-Yi

    2012-01-01

    Corynebacterium glutamicum is widely used for industrial production of various amino acids and vitamins, and there is growing interest in engineering this bacterium for more commercial bioproducts such as γ-aminobutyric acid (GABA). In this study, a C. glutamicum GABA-specific transporter (GabPCg) encoded by ncgl0464 was identified and characterized. GabPCg plays a major role in GABA uptake and is essential to C. glutamicum growing on GABA. GABA uptake by GabPCg was weakly competed by l-Asn and l-Gln and stimulated by sodium ion (Na+). The Km and Vmax values were determined to be 41.1 ± 4.5 μM and 36.8 ± 2.6 nmol min−1 (mg dry weight [DW])−1, respectively, at pH 6.5 and 34.2 ± 1.1 μM and 67.3 ± 1.0 nmol min−1 (mg DW)−1, respectively, at pH 7.5. GabPCg has 29% amino acid sequence identity to a previously and functionally identified aromatic amino acid transporter (TyrP) of Escherichia coli but low identities to the currently known GABA transporters (17% and 15% to E. coli GabP and Bacillus subtilis GabP, respectively). The mutant RES167 Δncgl0464/pGXKZ9 with the GabPCg deletion showed 12.5% higher productivity of GABA than RES167/pGXKZ9. It is concluded that GabPCg represents a new type of GABA transporter and is potentially important for engineering GABA-producing C. glutamicum strains. PMID:22307305

  10. Heterogeneous uptake of amines by citric acid and humic acid.

    PubMed

    Liu, Yongchun; Ma, Qingxin; He, Hong

    2012-10-16

    Heterogeneous uptake of methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) onto citric acid and humic acid was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer at 298 K. Acid-base reactions between amines and carboxylic acids were confirmed. The observed uptake coefficients of MA, DMA, and TMA on citric acid at 298 K were measured to be 7.31 ± 1.13 × 10(-3), 6.65 ± 0.49 × 10(-3), and 5.82 ± 0.68 × 10(-3), respectively, and showed independence of sample mass. The observed uptake coefficients of MA, DMA, and TMA on humic acid at 298 K increased linearly with sample mass, and the true uptake coefficients of MA, DMA, and TMA were measured to be 1.26 ± 0.07 × 10(-5), 7.33 ± 0.40 × 10(-6), and 4.75 ± 0.15 × 10(-6), respectively. Citric acid, having stronger acidity, showed a higher reactivity than humic acid for a given amine; while the steric effect of amines was found to govern the reactivity between amines and citric acid or humic acid.

  11. Fatty acid uptake in normal human myocardium

    SciTech Connect

    Vyska, K.; Meyer, W.; Stremmel, W.; Notohamiprodjo, G.; Minami, K.; Machulla, H.J.; Gleichmann, U.; Meyer, H.; Koerfer, R. )

    1991-09-01

    Fatty acid binding protein has been found in rat aortic endothelial cell membrane. It has been identified to be a 40-kDa protein that corresponds to a 40-kDa fatty acid binding protein with high affinity for a variety of long chain fatty acids isolated from rat heart myocytes. It is proposed that this endothelial membrane fatty acid binding protein might mediate the myocardial uptake of fatty acids. For evaluation of this hypothesis in vivo, influx kinetics of tracer-labeled fatty acids was examined in 15 normal subjects by scintigraphic techniques. Variation of the plasma fatty acid concentration and plasma perfusion rate has been achieved by modulation of nutrition state and exercise conditions. The clinical results suggest that the myocardial fatty acid influx rate is saturable by increasing fatty acid plasma concentration as well as by increasing plasma flow. For analysis of these data, functional relations describing fatty acid transport from plasma into myocardial tissue in the presence and absence of an unstirred layer were developed. The fitting of these relations to experimental data indicate that the free fatty acid influx into myocardial tissue reveals the criteria of a reaction on a capillary surface in the vicinity of flowing plasma but not of a reaction in extravascular space or in an unstirred layer and that the fatty acid influx into normal myocardium is a saturable process that is characterized by the quantity corresponding to the Michaelis-Menten constant, Km, and the maximal velocity, Vmax, 0.24 {plus minus} 0.024 mumol/g and 0.37 {plus minus} 0.013 mumol/g(g.min), respectively. These data are compatible with a nondiffusional uptake process mediated by the initial interaction of fatty acids with the 40-kDa membrane fatty acid binding protein of cardiac endothelial cells.

  12. Recombinant glucose uptake system

    DOEpatents

    Ingrahm, Lonnie O.; Snoep, Jacob L.; Arfman, Nico

    1997-01-01

    Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

  13. Uptake and distribution of nitrogen from acidic fog within a ponderosa pine (Pinus ponderosa Laws.)/litter/soil system

    SciTech Connect

    Fenn, M.E.; Leininger, T.D.

    1995-11-01

    The magnitude and importance of wet deposition of N in forests of the South Coast (Los Angeles) Air Basin have not been well characterized. We exposed 3-yr-old ponderosa pine (Pinus ponderosa Laws.) seedlings growing in native forest soil to acidic fog treatments (pH 3.1) simulating fog chemistry from a pine forest near Los Angeles, California. Fog solutions contained either {sup 15}NH{sub 4}{sup +}, {sup 15}NO{sub 3}{sup {minus}}, or unlabeled N. The fog treatments were applied in open-top chambers in six 5-hr exposures. Soil treatments within each of the fog exposures were bare soil, soil overlain with L- and F-litter, and soil covered with plastic during the fog events to prevent fogwater from contacting soil. Seedlings were harvested and samples were collected 15 wk after the fog treatments. Uptake of {sup 15}N by roots was by far the dominant pathway for plant assimilation of fog-deposited {sup 15}N. Deposition of N in fog supplied 9.4% and 8.7% of the total N in current-year crown biomass in the litter-overlay and bare-soil treatments, respectively. Total N concentrations in every plant fraction except current-year stems were significantly higher in the bare-soil treatment than in the plastic-covered soil treatment. Less than 5% of the {sup 15}N deposited directly to the seedling crowns was retained by the plants in the covered-soil treatment, whereas 57% of the {sup 15}N deposited to the seedling/litter/soil systems was incorporated into plant biomass. The litter layers retained {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NO{sub 3}. Data from this study suggest that N deposited from fog may be an important source of N for plant growth in forests of the SCAB where fog occurrence and pollution exposure coincide. 5 refs., 5 figs., 3 tabs.

  14. Uptake of 2, 4-Dichlorophenoxyacetic acid by Pseudomonas fluorescens

    USGS Publications Warehouse

    Wedemeyer, G.A.

    1966-01-01

    WEDEMEYER, GARY (Fish-Pesticide Research Laboratory, Denver, Colo.). Uptake of 2,4-dichlorophenoxyacetic acid by Pseudomonas fluorescens. Appl. Microbiol. 14:486-491. 1966.-Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “nonmetabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carriermediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranylion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

  15. Mechanisms of 5-aminolevulic acid ester uptake in mammalian cells

    PubMed Central

    Rodriguez, Lorena; Batlle, Alcira; Di Venosa, Gabriela; Battah, Sinan; Dobbin, Paul; MacRobert, Alexander J; Casas, Adriana

    2006-01-01

    The porphyrin precursor 5-aminolevulinic acid (ALA) is being widely used in photodynamic therapy of cancer. Improvement in ALA delivery has been sought through the use of ALA derivatives, in particular the esterification of ALA with aliphatic alcohols, which in certain cases can improve cellular penetration and selectivity. ALA uptake systems appear to be distinctive for each cell type. The LM3 mammary adenocarcinoma cell line takes ALA up by BETA transporters. In this work, we investigated ALA derivative transport systems through the inhibition of radiolabelled ALA uptake in the LM3 cells. We also performed inhibition studies of γ-aminobutyric acid (GABA) uptake. The more lipohilic ALA derivatives hexyl-ALA and undecanoyl-ALA inhibit ALA uptake, whereas methyl-ALA, R, S-ALA-2-(hydroxymethyl)tetrahydropyranyl ester and the dendron aminomethane tris methyl 5-ALA does not inhibit ALA uptake. A similar pattern was found for GABA, except that the dendron inhibited GABA uptake. However, hexyl-ALA and undecanoyl-ALA are not taken up by BETA transporters, but by simple diffusion, although they still inhibit ALA uptake by binding to the cell membrane. These results show that different modifications to the ALA molecule lead to different uptake mechanisms. Whereas ALA is taken up by BETA transporters, none of the ALA derivatives shares the same mechanism. Knowledge of the mechanisms of ALA derivatives entry into the cells is essential to understand and improve ALA-mediated PDT and to the design of new ALA derivatives that may be taken up at a higher rate than ALA. PMID:16432502

  16. Uptake of 2,4-Dichlorophenoxyacetic Acid by Pseudomonas fluorescens

    USGS Publications Warehouse

    Wedemeyer, Gary

    1966-01-01

    Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carrier-mediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranyl ion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

  17. Amino acid uptake in rust fungi.

    PubMed

    Struck, Christine

    2015-01-01

    The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia, or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid transporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways.

  18. Effect of zinc source and picolinic acid on /sup 65/Zn uptake in an in vitro continuous-flow perfusion system for pig and poultry intestinal segments

    SciTech Connect

    Hill, D.A.; Peo, E.R. Jr.; Lewis, A.J.

    1987-10-01

    Twenty weanling pigs and fourteen 9-wk-old broiler chickens were used in three continuous-flow in vitro perfusion experiments using noneverted intestinal sacs to 1) determine differences in /sup 65/Zn absorption due to location within the intestinal tract, 2) evaluate /sup 65/Zn uptake from ZnCl/sub 2/ and Zn-methionine (ZnMet) with or without added picolinic acid (PA) in pig intestinal sacs and 3) evaluate /sup 65/Zn uptake from ZnCl/sub 2/ and ZnMet in chicken intestinal sacs. No differences in /sup 65/Zn uptake due to gut segment position were observed in the pigs. A Zn source x PA interaction was observed for /sup 65/Zn uptake into the pig gut tissue and for /sup 65/Zn uptake to the serosal side of the gut sacs. Total /sup 65/Zn absorption in the pig gut sacs from the two Zn sources was not different, but the addition of a 5 M ratio of PA to Zn depressed /sup 65/Zn absorption. No differences were observed in total /sup 65/Zn absorption or /sup 65/Zn uptake in poultry gut sac tissue. There was, however, greater uptake of /sup 65/Zn from ZnCl/sub 2/ to the serosal side of the sacs than from ZnMet. The data indicate that /sup 65/Zn from ZnCl/sub 2/ and ZnMet is similar in total absorption and that the addition of PA depresses Zn uptake.

  19. Increased Brain Fatty Acid Uptake in Metabolic Syndrome

    PubMed Central

    Karmi, Anna; Iozzo, Patricia; Viljanen, Antti; Hirvonen, Jussi; Fielding, Barbara A.; Virtanen, Kirsi; Oikonen, Vesa; Kemppainen, Jukka; Viljanen, Tapio; Guiducci, Letizia; Haaparanta-Solin, Merja; Någren, Kjell; Solin, Olof; Nuutila, Pirjo

    2010-01-01

    OBJECTIVE To test whether brain fatty acid uptake is enhanced in obese subjects with metabolic syndrome (MS) and whether weight reduction modifies it. RESEARCH DESIGN AND METHODS We measured brain fatty acid uptake in a group of 23 patients with MS and 7 age-matched healthy control subjects during fasting conditions using positron emission tomography (PET) with [11C]-palmitate and [18F]fluoro-6-thia-heptadecanoic acid ([18F]-FTHA). Sixteen MS subjects were restudied after 6 weeks of very low calorie diet intervention. RESULTS At baseline, brain global fatty acid uptake derived from [18F]-FTHA was 50% higher in patients with MS compared with control subjects. The mean percentage increment was 130% in the white matter, 47% in the gray matter, and uniform across brain regions. In the MS group, the nonoxidized fraction measured using [11C]-palmitate was 86% higher. Brain fatty acid uptake measured with [18F]-FTHA-PET was associated with age, fasting serum insulin, and homeostasis model assessment (HOMA) index. Both total and nonoxidized fractions of fatty acid uptake were associated with BMI. Rapid weight reduction decreased brain fatty acid uptake by 17%. CONCLUSIONS To our knowledge, this is the first study on humans to observe enhanced brain fatty acid uptake in patients with MS. Both fatty acid uptake and accumulation appear to be increased in MS patients and reversed by weight reduction. PMID:20566663

  20. Cystine and dibasic amino acid uptake by opossum kidney cells

    SciTech Connect

    States, B.; Segal, S. )

    1990-06-01

    The characteristics of the uptake of L-cystine by the continuous opossum kidney cell line, OK, were examined. Uptake of cystine is rapid and, in contrast to other continuous cultured cell lines, these cells retain the cystine/dibasic amino acid transport system which is found in vivo and in freshly isolated kidney tissue. Confluent monolayers of cells also fail to show the presence of the cystine/glutamate transport system present in LLC-PK1 cells, fibroblasts, and cultured hepatocytes. Uptake of cystine occurs via a high-affinity saturable process which is independent of medium sodium concentration. The predominant site of cystine transport is across the apical cell membrane. The intracellular concentration of GSH far exceeds that of cystine with a ratio greater than 100:1 for GSH:cysteine. Incubation of cells for 5 minutes with a physiological level of labelled cystine resulted in the labelling of 66% and 5% of the total intracellular cysteine and glutathione, respectively. The ability of these cells to reflect the shared cystine/dibasic amino acid transport system makes them a suitable model for investigation of the cystine carrier which is altered in human cystinuria.

  1. Nucleic acids encoding metal uptake transporters and their uses

    DOEpatents

    Schroeder, Julian I.; Antosiewicz, Danuta M.; Schachtman, Daniel P.; Clemens, Stephan

    1999-01-01

    The invention provides LCT1 nucleic acids which encode metal ion uptake transporters. The invention also provides methods of modulating heavy metal and alkali metal uptake in plants. The methods involve producing transgenic plants comprising a recombinant expression cassette containing an LCT1 nucleic acid linked to a plant promoter.

  2. Characterization of ascorbic acid uptake by isolated rat kidney cells

    SciTech Connect

    Bowers-Komro, D.M.; McCormick, D.B. )

    1991-01-01

    Isolated kidney cells accumulated L(1-14C)ascorbic acid in a time-dependent manner and reached a steady state after 15 min at 37 degrees C. Initial velocity for uptake was over 300 pmol/mg protein per min when cells were separated from the bathing solution using a density gradient established during centrifugation. The uptake process was saturable with an apparent concentration at half maximal uptake of 36 mumols/L. Ascorbate uptake was reduced by metabolic inhibitors and was temperature dependent. Although ascorbic acid is an acid anion at pH 7.4, uptake did not appear to be inhibited by other acid anions such as p-aminohippurate and probenecid; however, involvement of the ion gradient established by Na+, H(+)-adenosine triphosphatase could not be confirmed. Replacing the sodium ion with other monovalent ions reduced the accumulation of ascorbate significantly. Isoascorbic and dehydroascorbic acids inhibited ascorbate uptake (34 and 13 mmol/L, respectively), whereas high concentrations of glucose showed some stimulation. These findings indicated that ascorbic acid is reabsorbed by the kidney in a sodium-dependent active transport process that is not common to other acid anions and has some specificity for the ascorbic acid structure.

  3. Uptake mechanism of valproic acid in human placental choriocarcinoma cell line (BeWo).

    PubMed

    Ushigome, F; Takanaga, H; Matsuo, H; Tsukimori, K; Nakano, H; Ohtani, H; Sawada, Y

    2001-04-13

    Valproic acid is an anticonvulsant widely used for the treatment of epilepsy. However, valproic acid is known to show fetal toxicity, including teratogenicity. In the present study, to elucidate the mechanisms of valproic acid transport across the blood-placental barrier, we carried out transcellular transport and uptake experiments with human placental choriocarcinoma epithelial cells (BeWo cells) in culture. The permeability coefficient of [3H]valproic acid in BeWo cells for the apical-to-basolateral flux was greater than that for the opposite flux, suggesting a higher unidirectional transport in the fetal direction. The uptake of [3H]valproic acid from the apical side was temperature-dependent and enhanced under acidic pH. In the presence of 50 microM carbonyl cyanide p-trifluoromethoxylhydrazone, the uptake of [3H]valproic acid was significantly reduced. A metabolic inhibitor, 10 mM sodium azide, also significantly reduced the uptake of [3H]valproic acid. Therefore, valproic acid is actively transported in a pH-dependent manner on the brush-border membrane of BeWo cells. Kinetic analysis of valproic acid uptake revealed the involvement of a non-saturable component and a saturable component. The Michaelis constant for the saturable transport (K(t)) was smaller under acidic pH, suggesting a proton-linked active transport mechanism for valproic acid in BeWo cells. In the inhibitory experiments, some short-chain fatty acids, such as acetic acid, lactic acid, propanoic acid and butyric acid, and medium-chain fatty acids, such as hexanoic acid and octanoic acid, inhibited the uptake of [3H]valproic acid. The uptake of [3H]valproic acid was also significantly decreased in the presence of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, salicylic acid and furosemide, which are well-known inhibitors of the anion exchange system. Moreover, p-aminohippuric acid significantly reduced the uptake of [3H]valproic acid. These results suggest that an active transport

  4. Two Uptake Systems for Fructose in Lactococcus lactis subsp. cremoris FD1 Produce Glycolytic and Gluconeogenic Fructose Phosphates and Induce Oscillations in Growth and Lactic Acid Formation

    PubMed Central

    Benthin, Stig; Nielsen, Jens; Villadsen, John

    1993-01-01

    Fructose transport in lactococci is mediated by two phosphotransferase systems (PTS). The constitutive mannose PTS has a broad specificity and may be used for uptake of fructose with a fructose saturation constant (KFru) of 0.89 mM, giving intracellular fructose 6-phosphate. The inducible fructose PTS has a very small saturation constant (KFru, <17 μM), and the fructose 1-phosphate produced enters the Embden-Meyerhof-Parnas (EMP) pathway as fructose 1,6-diphosphate. Growth in batch cultures of Lactococcus lactis subsp. cremoris FD1 in a yeast extract medium with fructose as the only sugar is poor both with respect to specific growth rate and biomass yield, whereas the specific lactic acid production rate is higher than those in similar fermentations on other sugars metabolized via the EMP pathway, e.g., glucose. In fructose-limited chemostat cultures, the biomass concentration exhibits a strong correlation with the dilution rate, and starting a continuous culture at the end of a batch fermentation leads to large and persistent oscillations in the biomass concentration and specific lactic acid production rate. Two proposed mechanisms underlying this strange growth pattern follow. (i) Fructose transported via the fructose PTS cannot be converted into essential biomass precursors (glucose 6-phosphate or fructose 6-phosphate), because L. lactis subsp. cremoris FD1 is devoid of fructose 1,6-diphosphatase activity. (ii) The fructose PTS apparently produces a metabolite (presumably fructose 1-phosphate) which exerts catabolite repression of both mannose PTS and lactose PTS. Since the repressed mannose PTS and lactose PTS are shown to have identical maximum molar transport rates, the results indicate that it is the general PTS proteins which are repressed. PMID:16349061

  5. Differential Inhibition by Ferulic Acid of Nitrate and Ammonium Uptake in Zea mays L. 1

    PubMed Central

    Bergmark, Christine L.; Jackson, William A.; Volk, Richard J.; Blum, Udo

    1992-01-01

    The influence of the allelopathic compound ferulic acid (FA) on nitrogen uptake from solutions containing both NO3− and NH4+ was examined in 8-day-old nitrogen-depleted corn (Zea mays L.) seedlings. Concurrent effects on uptake of Cl− and K+ also were assessed. The presence of 250 micromolar FA inhibited the initial (0-1 hours) rate of NO3− uptake and also prevented development of the NO3−-inducible accelerated rate. The pattern of recovery when FA was removed was interpreted as indicating a rapid relief of FA-restricted NO3− uptake activity, followed by a reinitiation of the induction of that activity. No inhibition of NO3− reduction was detected. Ammonium uptake was less sensitive than NO3− uptake to inhibition by FA. An inhibition of Cl− uptake occurred as induction of the NO3− transport system developed in the absence of FA. Alterations of Cl− uptake in the presence of FA were, therefore, a result of a beneficial effect, because NO3− uptake was restricted, and a direct inhibitory effect. The presence of FA increased the initial net K+ loss from the roots during exposure to the low K, ammonium nitrate uptake solution and delayed the recovery to positive net uptake, but it did not alter the general pattern of the response. The implications of the observations are discussed for growth of plants under natural conditions and cultural practices that foster periodic accumulation of allelopathic substances. PMID:16668689

  6. Metabolic regulation of amino acid uptake in marine waters

    SciTech Connect

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  7. Uptake of benzoic acid and chloro-substituted benzoic acids by alcaligenes denitrificans BRI 3010 and BRI 6011

    SciTech Connect

    Miguez, C.B.; Ingram, J.M.; MacLeod, R.A.

    1995-12-01

    The mechanism of uptake of benzoic and 2,4-dichlorobenzoic acid (2,4-DCBA) by Alcaligenes denitrificans BRI 3010 and BRI 6011 and Pseudomonas sp. strain B13, three organisms capable of degrading isomers of chlorinated benzoic acids, was investigated. In all three organisms, uptake of benzoic acid was inducible. For benzoic acid uptake into BRI 3010, monophasic saturation kinetics with apparent K{sub m} and V{sub max} values of 1.4 {mu}M and 3.2 nmol/min/mg of cell dry weight, respectively, were obtained. For BRI 6011, biphasic saturation kinetics were observed, suggesting presence of two uptake systems for benzoic acid with distinct K{sub m} (0.72 and 5.3 {mu}M) and V{sub max} (3.3 and 4.6 nmol/min/mg of cell dry weight) values. BRI 3010 and BRI 6011 accumulated benzoic acid against a concentration gradient by a factor of 8 and 10, respectively. A wide range of structural analogs, at 50-fold excess concentrations, inhibited benzoic acid uptake by BRI 3010 and BRI 6011, whereas with B13, only 3-chlorobenzoic acid was an effective inhibitor. For BRI 3010 and BRI 6011, the inhibition by the structural analogs was not of a competitive nature. Uptake of benzoic acid by BRI 3010 and BRI 6011 was inhibited by KCN, by the protonophore 3,5,3`, 4`-tetrachlorosalicylanilide (TCS), and, for BRI 6011, by anaerobiosis unless nitrate was present, thus indicating that energy was required for the uptake process. Uptake of 2,4-DCBA by BRI 6011 was constitutive and saturation uptake kinetics were not observed. Uptake of 2,4-DCBA by BRI 6011 was inhibited by KCN, TCS, and anaerobiosis even if nitrate was present, but the compound was not accumulated intracellularly against a concentration gradient. Uptake of 2,4-DCBA by BRI 6011 appears to occur by passive diffusion into the cell down its concentration gradient, which is maintained by the intracellular metabolism of the compound. This process could play an important role in the degradation of xenobiotic compounds by microorganisms.

  8. Cellular fatty acid uptake: a pathway under construction.

    PubMed

    Su, Xiong; Abumrad, Nada A

    2009-03-01

    Membrane uptake of long-chain fatty acids (FAs) is the first step in cellular FA utilization and a point of metabolic regulation. CD36 facilitates a major fraction of FA uptake by key tissues. This review highlights the contribution of CD36 to pathophysiology in rodents and humans. Novel concepts regarding regulation of CD36-facilitated uptake are discussed (i.e. the role of membrane rafts and caveolae, CD36 recycling between intracellular depots and the membrane, and chemical modifications of the protein that impact its turnover and recruitment). Importantly, CD36 membrane levels and turnover are abnormal in diabetes, resulting in dysfunctional FA utilization. In addition, variants in the CD36 gene were shown recently to influence susceptibility for the metabolic syndrome, which greatly increases the risk of diabetes and heart disease. PMID:19185504

  9. Tracking the morphology of fulvic acids during water uptake

    NASA Astrophysics Data System (ADS)

    Zelenay, Veronika; Krepelova, Adela; Rudich, Yinon; Huthwelker, Thomas; Ammann, Markus

    2010-05-01

    a microdispenser or as aerosol particles on the sample holder of the microreactor. The resulting dry droplet residues reached a size of about 20 -30 μm or around 0.5 μm, respectively. Using this setup we could obtain unique images showing the microstructure of the fulvic acid before and during exposure to water vapor in situ. Significant changes in morphology occurred upon water uptake, and the system consisted of a solution with embedded micron-sized colloidal particles. This further allows linking the chemical functional groups with their degree of hydration. Additional measurements were performed with two fractionated fulvic acids of low (0.5-1 kDa) and high (10-30 kDa) molecular weight. Both fractions were first analyzed for their functional and their hygroscopic properties. Although the functional group analysis shows differences, the morphology of these two fractions was found to be similar. Under dry conditions, the residues were more homogeneous over the droplet dimensions than for the unfractionated samples. Under wet conditions, the two fractions differed in the amount of water taken up but were similar in the degree to which more phenolic subunits were apparent.

  10. Methanol Uptake by Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, L. T.; Essin, A. M.; Golden, D. M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The global methanol budget is currently unbalanced, with source terms significantly larger than the sinks terms. To evaluate possible losses of gaseous methanol to sulfate aerosols, the solubility and reactivity of methanol in aqueous sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosols is under investigation. Methanol will partition into sulfate aerosols according to its Henry's law solubility. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H*, for cold (196 - 220 K) solutions ranging between 45 and 70 wt % H2SO4. We have found that methanol solubility ranges from approx. 10(exp 5) - 10(exp 7) M/atm for UT/LS conditions. Solubility increases with decreasing temperature and with increasing sulfuric acid content. Although methanol is slightly more soluble than are acetone and formaldehyde, current data indicate that uptake by clean aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These solubility measurements include uptake due to physical solvation and any rapid equilibria which are established in solution. Reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H is not significant over our experimental time scale for solutions below 80 wt % H2SO4. To confirm this directly, results obtained using a complementary equilibrium measurement technique will also be presented.

  11. Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

  12. Dual capacity for nutrient uptake in Tetrahymena. V. Utilization of amino acids and proteins.

    PubMed

    Orias, E; Rasmussen, L

    1979-04-01

    We investigated the relative contributions of phagocytosis and plasma membrane transport to the uptake of amino acids and a protein (egg albumin) in amounts which allow Tetrahymena thermophila to grow and multiply. We used a mutant capable of indefinite growth without food vacuole formation (phagocytosis) and its wild type (phagocytosis-competent) isogenic parental strain. Our results suggest that phagocytosis is not required for free amino acid uptake, most or all of which can be attributed to carrier-mediated transport systems, apparently located on the plasma membrane. In contrast, phagocytosis is required for utilization of the protein. Proteins can supply required amino acids in amounts sufficient for growth only when food vacuoles are formed. We conclude that Tetrahymena thermophila either possesses no endocytic mechanisms at the cell surface other than food vacuole formation or, if it does, these putative mechanisms are not capable of nutritionally meaningful rates of protein uptake.

  13. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    NASA Technical Reports Server (NTRS)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  14. Role of fatty acid binding protein on hepatic palmitate uptake.

    PubMed

    Burczynski, F J; Zhang, M N; Pavletic, P; Wang, G Q

    1997-12-01

    Expression of hepatic fatty acid binding protein (FABP) mRNA is regulated by growth hormone. In the absence of growth hormone, there is a 60% reduction in FABP mRNA levels (S.A. Berry, J.-B Yoon, U. List, and S. Seelig. J. Am. Coll. Nutr. 12:638-642. 1995). Previous work in our laboratory focused on the role of extracellular binding proteins in the hepatic uptake of long chain fatty acids. In the present study we were interested to determine the role of FABP in the transmembrane flux of long chain fatty acids. Using hepatocyte monolayers from control (n = 9) and hypophysectomized (n = 6) rats, we investigated the uptake of [3H]palmitate in the presence and absence of albumin. In the absence of albumin, total hepatocyte [3H]palmitate clearance rates from control (17.2 +/- 1.5 microL.mg-1 protein.s-1; mean +/- SEM; n = 9) and hypophysectomized (15.5 +/- 2.1 microL.mg-1 protein.s-1; n = 6) animals were similar (p > 0.05). In the presence of 2 microM albumin the total [3H]palmitate clearance rate from control hepatocytes (1.63 +/- 0.11 microL.mg-1 protein.s-1; n = 9) was significantly larger (40%) than from hepatocytes obtained from hypophysectomized (0.97 +/- 0.15 microL.mg-1 protein.s-1; n = 6; p < 0.01) animals. SDS-PAGE electrophoresis revealed that plasma membrane FABP levels from control and hypophysectomized animals were similar. However, there was a 49% decrease in the cytosolic FABP levels of hepatocytes isolated from hypophysectomized as compared with control animals. The decreased cytosolic FABB levels paralleled the decrease in palmitate uptake. We conclude that in the absence of extracellular binding proteins the rate-limiting step in the overall uptake of long chain fatty acids is diffusion to the cell surface. However, in the presence of albumin, the rate of palmitate uptake is determined primarily by cytosolic FABP levels.

  15. Modelling water uptake efficiency of root systems

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  16. Uptake and metabolic effects of salicylic acid on the pulvinar motor cells of Mimosa pudica L.

    PubMed

    Dédaldéchamp, Fabienne; Saeedi, Saed; Fleurat-Lessard, Pierrette; Roblin, Gabriel

    2014-01-01

    In this paper, the salicylic acid (o-hydroxy benzoic acid) (SA) uptake by the pulvinar tissues of Mimosa pudica L. pulvini was shown to be strongly pH-dependent, increasing with acidity of the assay medium. This uptake was performed according to a unique affinity system (K(m) = 5.9 mM, V(m) = 526 pmol mgDW(-1)) in the concentration range of 0.1-5 mM. The uptake rate increased with increasing temperature (5-35 °C) and was inhibited following treatment with sodium azide (NaN3) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), suggesting the involvement of an active component. Treatment with p-chloromercuribenzenesulfonic acid (PCMBS) did not modify the uptake, indicating that external thiol groups were not necessary. KCl, which induced membrane depolarization had no significant effect, and fusicoccin (FC), which hyperpolarized cell membrane, stimulated the uptake, suggesting that the pH component of the proton motive force was likely a driving force. These data suggest that the SA uptake by the pulvinar tissues may be driven by two components: an ion-trap mechanism playing a pivotal role and a putative carrier-mediated mechanism. Unlike other benzoic acid derivatives acting as classical respiration inhibitors (NaN3 and KCN), SA modified the pulvinar cell metabolism by increasing the respiration rate similar to CCCP and 2,4-dinitrophenol (DNP). Furthermore, SA inhibited the osmoregulated seismonastic reaction in a pH dependent manner and induced characteristic damage to the ultrastructural features of the pulvinar motor cells, particularly at the mitochondrial level.

  17. Uptake of auxins into membrane vesicles isolated from pea stems: an in vitro auxin transport system

    SciTech Connect

    Slone, J.H.

    1985-01-01

    The objective of this research was to test the applicability of the chemiosmotic theory of auxin transport to a subcellular system. Membrane vesicles were isolated from the basal portion of the third internode of etiolated pea plants (Pisum sativum L. var. Alaska) by differential centrifugation. Uptake of auxin was determined by adding /sup 14/C-labeled indoleacetic acid (IAA) to vesicles. Nigericin, a monovalent cation ionophore, and the electrogenic protonophore, carbonyl-cyanide m-chlorophenylhydrazone (CCCP), at micromolar concentrations abolished saturable uptake. Bursting vesicles by sonication, osmotic shock and freeze/thawing also eliminated saturable uptake. As the temperature increased from 0 to 30/sup 0/C, saturable uptake decreased markedly. Nonsaturable auxin uptake was less affected by these treatments. The pH gradient-dependent uptake of auxin appeared to be a transmembrane uptake of auxin into the vesicles rather than surface binding. Unlabeled IAA, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-naphthaleneacetic acid (NAA) at low concentrations reduced the saturable accumulation of (/sup 14/C)IAA in vesicles, while phenylacetic acid, benzoic acid, and 1-NAA were effective only at high concentrations. Kinetic analysis revealed two types of sites: a high affinity site with an uptake capacity of 25 to 40 pmoles/g tissue, and a low affinity site with an uptake capacity of 260 to 600 pmole/g tissue, fresh wt. In conclusion, several principal elements of an auxin transport system, as specific by the chemiosmotic theory of polar auxin transport, were present in membrane vesicles isolated from relatively mature pea stem tissue. However, one important aspect of the theory was not demonstrated in this in vitro system - a TIBA/NPA-sensitive auxin efflux. The kinetics and specificity of auxin uptake strongly suggested that this system was physiologically significant.

  18. Relating physical state and reactivity: humidity dependent ozone uptake on tannic and shikimic acid

    NASA Astrophysics Data System (ADS)

    Steimer, S.; Huisman, A.; Krieger, U.; Lampimäki, M.; Marcolli, C.; Peter, T.; Ammann, M.

    2012-04-01

    Atmospheric aerosols are an important focus of environmental research due to their effect on climate and human health. Recent findings show that organic aerosol particles are capable of forming amorphous solids and semi-solids under atmospheric conditions [1]. Such particles should be highly viscous, leading to low diffusivity within the bulk. This would then slow down eventual chemical reactions in the bulk, thereby increasing the lifetime of the organic compounds involved. First indications of such behavior were recently shown for the reaction of thin protein films with ozone [2]. To investigate the influence of the physical state on the reactivity of atmospherically relevant compounds, the uptake of ozone on two different organics was measured using a coated wall flow tube system. The investigated organic compounds are tannic acid, which is a proxy for atmospheric polyphenolic materials, and shikimic acid, a constituent of biomass burning aerosols. The viscosity of the organic film was adjusted by varying the humidity of the system, assuming a correlation between the two parameters due to water acting as a plasticizer. The investigated humidity range was 0% - 95% RH for tannic and 0% - 92% RH for shikimic acid. It was found that both of the compounds show a long term uptake of ozone which lasts for more than 20 h. The uptake coefficient is clearly humidity dependent and increases by close to two orders of magnitude between driest and wettest conditions. At a given humidity, shikimic acid is the more reactive compound. The measured humidity dependence supports the hypothesis that the uptake coefficient is a strong function of the diffusion coefficient of ozone in the organic film. 1. Virtanen, A., et al., An amorphous solid state of biogenic secondary organic aerosol particles. Nature, 2010. 467(7317): p. 824-827. 2. Shiraiwa, M., et al., Gas uptake and chemical aging of semisolid organic aerosol particles. Proceedings of the National Academy of Sciences of the

  19. Helicobacter pylori's cholesterol uptake impacts resistance to docosahexaenoic acid.

    PubMed

    Correia, Marta; Casal, Susana; Vinagre, João; Seruca, Raquel; Figueiredo, Ceu; Touati, Eliette; Machado, José C

    2014-05-01

    Helicobacter pylori colonizes half of the world population and is associated with gastric cancer. We have previously demonstrated that docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid known for its anti-inflammatory and antitumor effects, directly inhibits H. pylori growth in vitro and in mice. Nevertheless, the concentration of DHA shown to reduce H. pylori mice gastric colonization was ineffective in vitro. Related to the auxotrophy of H. pylori for cholesterol, we hypothesize that other mechanisms, in addition to DHA direct antibacterial effect, must be responsible for the reduction of the infection burden. In the present study we investigated if DHA affects also H. pylori growth, by reducing the availability of membrane cholesterol in the epithelial cell for H. pylori uptake. Levels of cholesterol in gastric epithelial cells and of cholesteryl glucosides in H. pylori were determined by thin layer chromatography and gas chromatography. The consequences of epithelial cells' cholesterol depletion on H. pylori growth were assessed in liquid cultures. We show that H. pylori uptakes cholesterol from epithelial cells. In addition, DHA lowers cholesterol levels in epithelial cells, decreases its de novo synthesis, leading to a lower synthesis of cholesteryl glucosides by H. pylori. A previous exposition of H. pylori to cholesterol influences the bacterium response to the direct inhibitory effect of DHA. Overall, our results suggest that a direct effect of DHA on H. pylori survival is modulated by its access to epithelial cell cholesterol, supporting the notion that cholesterol enhances the resistance of H. pylori. The cholesterol-dependent resistance of H. pylori to antimicrobial compounds raises new important aspects for the development of new anti-bacterial strategies. PMID:24447914

  20. Helicobacter pylori's cholesterol uptake impacts resistance to docosahexaenoic acid.

    PubMed

    Correia, Marta; Casal, Susana; Vinagre, João; Seruca, Raquel; Figueiredo, Ceu; Touati, Eliette; Machado, José C

    2014-05-01

    Helicobacter pylori colonizes half of the world population and is associated with gastric cancer. We have previously demonstrated that docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid known for its anti-inflammatory and antitumor effects, directly inhibits H. pylori growth in vitro and in mice. Nevertheless, the concentration of DHA shown to reduce H. pylori mice gastric colonization was ineffective in vitro. Related to the auxotrophy of H. pylori for cholesterol, we hypothesize that other mechanisms, in addition to DHA direct antibacterial effect, must be responsible for the reduction of the infection burden. In the present study we investigated if DHA affects also H. pylori growth, by reducing the availability of membrane cholesterol in the epithelial cell for H. pylori uptake. Levels of cholesterol in gastric epithelial cells and of cholesteryl glucosides in H. pylori were determined by thin layer chromatography and gas chromatography. The consequences of epithelial cells' cholesterol depletion on H. pylori growth were assessed in liquid cultures. We show that H. pylori uptakes cholesterol from epithelial cells. In addition, DHA lowers cholesterol levels in epithelial cells, decreases its de novo synthesis, leading to a lower synthesis of cholesteryl glucosides by H. pylori. A previous exposition of H. pylori to cholesterol influences the bacterium response to the direct inhibitory effect of DHA. Overall, our results suggest that a direct effect of DHA on H. pylori survival is modulated by its access to epithelial cell cholesterol, supporting the notion that cholesterol enhances the resistance of H. pylori. The cholesterol-dependent resistance of H. pylori to antimicrobial compounds raises new important aspects for the development of new anti-bacterial strategies.

  1. Huntington disease and Tourette syndrome. II. Uptake of glutamic acid and other amino acids by fibroblasts.

    PubMed

    Comings, D E; Goetz, I E; Holden, J; Holtz, J

    1981-03-01

    Injection of kainic acid, a rigid analog of the excitatory neurotransmitter glutamic acid (glu), into the neostriatum of rats produces a condition that mimics Huntington disease (HD) in at least 12 different morphological and biochemical parameters. These results suggested that one of the possible basic mechanisms in HD is a defect in the presynaptic of glial uptake of glu, resulting in chronic hyperstimulation and death of a specific set of neurons. To test this hypothesis, the uptake of glu was studied in 12 carefully matched sets of control-HD pairs and two lines of Tourette syndrome fibroblasts. Although the first six sets suggested a glutamate transport defect in HD cells, examination of 12 sets indicated that there were no significant differences between control and HD cells. The fibroblasts showed both a high and low affinity uptake of glutamic acid. Sodium dependent uptake of L-glutamate (L-glu) minus D-glutamate (D-glu) at 100, 1,000, and 10,000 Micrometers glutamate was normal in HD and Tourette syndrome cells.

  2. Transporters in Arabidopsis roots mediating uptake of amino acids at naturally occurring concentrations.

    PubMed

    Svennerstam, Henrik; Jämtgård, Sandra; Ahmad, Iftikhar; Huss-Danell, Kerstin; Näsholm, Torgny; Ganeteg, Ulrika

    2011-07-01

    Recent studies of Arabidopsis have identified several transporters as being important for amino acid uptake. We used Arabidopsis plants with altered expression of lysine histidine transporter 1 (LHT1), amino acid permease 1 (AAP1) and amino acid permease 5 (AAP5) with the aim of disentangling the roles of each transporter in the uptake of different amino acids at naturally occurring concentrations (2-50 μM). LHT1 mutants displayed reduced uptake rates of L-Gln, L-Ala, L-Glu and L-Asp but not of L-Arg or L-Lys, while AAP5 mutants were affected in the uptake of L-Arg and L-Lys only. Double mutants (lht1aap5) exhibited reduced uptake of all tested amino acids. In the concentration range tested, AAP1 mutants did not display altered uptake rates for any of the studied amino acids. Expression analysis of amino acid transporter genes with important root functions revealed no major differences in the individual mutants other than for genes targeted for mutation. We conclude that LHT1 and AAP5, but not AAP1, are crucial for amino acid uptake at concentrations typically found in soils. LHT1 and AAP5 displayed complementary affinity spectra, and no redundancy with respect to gene expression was found between the two transporters, suggesting these two transporters have separate roles in amino acid uptake.

  3. Uptake of ozone to mixed sodium bromide/ citric acid solutions

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Tao; Steimle, Emilie; Bartels-Rausch, Thorsten; Kato, Shunsuke; Lampimäki, Markus; Brown, Matthew; van Bokhoven, Jeroen; Nolting, Frithjof; Kleibert, Armin; Türler, Andreas; Ammann, Markus

    2013-04-01

    Sea-salt solution - air interfaces play an important role in the chemistry of the marine boundary layer. The reaction of ozone (O3) with bromide is of interest in the context of formation of photolabile halogens (Br2, BrCl) in the marine boundary layer. Recent experiments have suggested that the bromide oxidation rate is related to the surface concentration of bromide [1] and inversely related to the gas phase concentration of O3, an indication for a precursor mediated reaction at the surface [2]. So far, the effect of organics (such as those occurring at the ocean surface or in marine aerosols) on the reaction of O3 with bromide aerosols has not been studied yet. In our study we investigate the uptake kinetics of O3 to a mixed solution of sodium bromide (NaBr) and citric acid (CA), which represents highly oxidized organic compounds present in the environment, with a well-established coated wall flow tube technique, which leads to exposure of the film to O3 allowing the heterogeneous reactions to take place and the loss of O3 being measured. The results indicate that the uptake of O3 to the films with the higher bromide concentrations (0.34M and 4M) is independent of the gas phase concentration and roughly consistent with uptake limited by reaction in the bulk. For the lower bromide concentration (84mM), however, we observe a trend of the uptake coefficient to decrease with increasing O3 concentration, indicating an increasing importance of a surface reaction. In an attempt to constrain the kinetic data, we employed X-ray photoelectron spectroscopy (XPS) to get insight into the surface composition of the aqueous solution - air interface. Previous XPS studies have shown that halide ion concentrations are enhanced at the aqueous solution air interface [3-4], which likely promotes the surface reactions of bromide or iodide with O3. A first XPS study of ternary solutions of KI with butanol indicated the importance of specific interactions of the cation with the alcohol

  4. Stromal uptake and transmission of acid is a pathway for venting cancer cell-generated acid.

    PubMed

    Hulikova, Alzbeta; Black, Nicholas; Hsia, Lin-Ting; Wilding, Jennifer; Bodmer, Walter F; Swietach, Pawel

    2016-09-01

    Proliferation and invasion of cancer cells require favorable pH, yet potentially toxic quantities of acid are produced metabolically. Membrane-bound transporters extrude acid from cancer cells, but little is known about the mechanisms that handle acid once it is released into the poorly perfused extracellular space. Here, we studied acid handling by myofibroblasts (colon cancer-derived Hs675.T, intestinal InMyoFib, embryonic colon-derived CCD-112-CoN), skin fibroblasts (NHDF-Ad), and colorectal cancer (CRC) cells (HCT116, HT29) grown in monoculture or coculture. Expression of the acid-loading transporter anion exchanger 2 (AE2) (SLC4A2 product) was detected in myofibroblasts and fibroblasts, but not in CRC cells. Compared with CRC cells, Hs675.T and InMyoFib myofibroblasts had very high capacity to absorb extracellular acid. Acid uptake into CCD-112-CoN and NHDF-Ad cells was slower and comparable to levels in CRC cells, but increased alongside SLC4A2 expression under stimulation with transforming growth factor β1 (TGFβ1), a cytokine involved in cancer-stroma interplay. Myofibroblasts and fibroblasts are connected by gap junctions formed by proteins such as connexin-43, which allows the absorbed acid load to be transmitted across the stromal syncytium. To match the stimulatory effect on acid uptake, cell-to-cell coupling in NHDF-Ad and CCD-112-CoN cells was strengthened with TGFβ1. In contrast, acid transmission was absent between CRC cells, even after treatment with TGFβ1. Thus, stromal cells have the necessary molecular apparatus for assembling an acid-venting route that can improve the flow of metabolic acid through tumors. Importantly, the activities of stromal AE2 and connexin-43 do not place an energetic burden on cancer cells, allowing resources to be diverted for other activities. PMID:27543333

  5. Stromal uptake and transmission of acid is a pathway for venting cancer cell-generated acid

    PubMed Central

    Hulikova, Alzbeta; Black, Nicholas; Hsia, Lin-Ting; Wilding, Jennifer; Bodmer, Walter F.; Swietach, Pawel

    2016-01-01

    Proliferation and invasion of cancer cells require favorable pH, yet potentially toxic quantities of acid are produced metabolically. Membrane-bound transporters extrude acid from cancer cells, but little is known about the mechanisms that handle acid once it is released into the poorly perfused extracellular space. Here, we studied acid handling by myofibroblasts (colon cancer-derived Hs675.T, intestinal InMyoFib, embryonic colon-derived CCD-112-CoN), skin fibroblasts (NHDF-Ad), and colorectal cancer (CRC) cells (HCT116, HT29) grown in monoculture or coculture. Expression of the acid-loading transporter anion exchanger 2 (AE2) (SLC4A2 product) was detected in myofibroblasts and fibroblasts, but not in CRC cells. Compared with CRC cells, Hs675.T and InMyoFib myofibroblasts had very high capacity to absorb extracellular acid. Acid uptake into CCD-112-CoN and NHDF-Ad cells was slower and comparable to levels in CRC cells, but increased alongside SLC4A2 expression under stimulation with transforming growth factor β1 (TGFβ1), a cytokine involved in cancer–stroma interplay. Myofibroblasts and fibroblasts are connected by gap junctions formed by proteins such as connexin-43, which allows the absorbed acid load to be transmitted across the stromal syncytium. To match the stimulatory effect on acid uptake, cell-to-cell coupling in NHDF-Ad and CCD-112-CoN cells was strengthened with TGFβ1. In contrast, acid transmission was absent between CRC cells, even after treatment with TGFβ1. Thus, stromal cells have the necessary molecular apparatus for assembling an acid-venting route that can improve the flow of metabolic acid through tumors. Importantly, the activities of stromal AE2 and connexin-43 do not place an energetic burden on cancer cells, allowing resources to be diverted for other activities. PMID:27543333

  6. Development of imidazole alkanoic acids as mGAT3 selective GABA uptake inhibitors.

    PubMed

    Hack, Silke; Wörlein, Babette; Höfner, Georg; Pabel, Jörg; Wanner, Klaus T

    2011-05-01

    A new series of potential GABA uptake inhibitors starting from of 1H-imidazol-4-ylacetic acid with the carboxylic acid side chain originating from different positions and varying in length have been synthesized and tested for the inhibitory potency at the four GABA uptake transporters mGAT1-4 stably expressed in HEK cells. Further two bicyclic compounds with a rigidified carboxylic acid side chain were included in this study. The results of the biological tests indicated that most ω-imidazole alkanoic and alkenoic acid derivatives exhibit the highest potencies as GABA uptake inhibitors at mGAT3.

  7. Root uptake of cationic amino acids by Arabidopsis depends on functional expression of amino acid permease 5.

    PubMed

    Svennerstam, Henrik; Ganeteg, Ulrika; Näsholm, Torgny

    2008-01-01

    * Specific transporters mediate uptake of amino acids by plant roots. Earlier studies have indicated that the lysine histidine transporter 1 and amino acid permease 1 participate in this process, but although plant roots have been shown to absorb cationic amino acids with high affinity, neither of these transporters seems to mediate transport of L-arginine (L-Arg) or L-lysine (L-Lys). * Here, a collection of T-DNA knockout mutants were screened for alterations in Arabidopsis root uptake rates of L-Arg and it was found that only the AAP5 mutant displayed clear phenotypic divergence on high concentrations of L-Arg. A second screen using low concentrations of (15)N-labelled L-Arg in the growth media also identified AAP5 as being involved in L-Arg acquisition. * Momentaneous root uptake of basic amino acids was strongly affected in AAP5 mutant lines, but their uptake of other types of amino acids was only marginally affected. Comparisons of the root uptake characteristics of AAP5 and LHT1 mutants corroborated the hypothesis that the two transporters have distinct affinity spectra in planta. * Root uptake of all tested amino acids, except L-aspartic acid (L-Asp), was significantly affected in double AAP5*LHT1 mutants, suggesting that these two transporters account for a major proportion of roots' uptake of amino acids at low concentrations. PMID:18681934

  8. Myristic Acid Enhances Diacylglycerol Kinase δ-Dependent Glucose Uptake in Myotubes.

    PubMed

    Wada, Yuko; Sakiyama, Shizuka; Sakai, Hiromichi; Sakane, Fumio

    2016-08-01

    Decreased expression of diacylglycerol kinase (DGK) δ in skeletal muscles attenuates glucose uptake and is closely related to the pathogenesis of type 2 diabetes. Therefore, up-regulation of DGKδ expression is thought to protect and improve glucose homoeostasis in type 2 diabetes. We recently determined that myristic acid (14:0), but not palmitic (16:0) or stearic (18:0) acid, significantly increased DGKδ2 protein expression in mouse C2C12 myotubes. In the current study, we analyzed whether myristic acid indeed enhances glucose uptake in C2C12 myotubes. We observed that myristic acid caused ~1.4-fold increase in insulin-independent glucose uptake. However, palmitic and stearic acids failed to enhance glucose uptake. DGKδ-specific siRNA decreased myristic acid-dependent increase of glucose uptake. Moreover, overexpression of DGKδ2 enhanced glucose uptake in C2C12 cells in the absence of myristic acid treatment. Taken together, these results strongly suggest that myristic acid enhances basal glucose uptake in myotubes in a DGKδ2 expression-dependent manner.

  9. Nutrient Uptake by Protocells: A Liposome Model System

    NASA Astrophysics Data System (ADS)

    Monnard, Pierre-Alain; Deamer, David W.

    2001-02-01

    Over the past decade, several liposome-based models for protocells have been developed. For example, liposome systems composed of polymerase enzymes encapsulated with their substrates have demonstrated that complex compartmentalized reactions can be carried out under conditions in which polymeric products are protected from degradation by hydrolytic enzymes present in the external medium. However, such systems do not have nutrient uptake mechanisms, which would be essential for primitive cells lacking the highly evolved nutrient transport processes present in all contemporary cells. In this report, we explore passive diffusion of solutes across lipid bilayers as one possible uptake mechanism. We have established conditions under which ionic substrates as large as ATP can permeate bilayers at rates capable of supplying an encapsulated template-dependent RNA polymerase. Furthermore, while allowing the permeation of monomer substrates such as ATP, bilayer vesicles selectively retained polymerization products as small as dimers and as large as a transfer RNA. These observations demonstrate that passive diffusion could be used by the earliest forms of cellular life for transport of important nutrients such as amino acids, phosphate, and phosphorylated organic solutes.

  10. Expression of the hepatocellular chloride-dependent sulfobromophthalein uptake system in Xenopus laevis oocytes.

    PubMed Central

    Jacquemin, E; Hagenbuch, B; Stieger, B; Wolkoff, A W; Meier, P J

    1991-01-01

    The expression of the basolateral chloride-activated organic anion uptake system of rat hepatocytes has been studied in Xenopus laevis oocytes. Injection of oocytes with rat liver poly(A)+RNA resulted in the functional expression of chloride-dependent sulfobromophthalein (BSP) uptake within 3-5 d. This expressed chloride-dependent BSP uptake system exhibited saturation kinetics (apparent Km approximately 6.2 microM) and efficiently extracted BSP from its binding sites on BSA. Furthermore, the chloride-activated portion of BSP uptake was inhibited by bilirubin (10 microM; inhibition 53%), 4,4'-diisothiocyano-2,2-disulfonic acid stilbene (DIDS, 100 microM; 80%), taurocholate (100 microM; 80%), and cholate (200 microM; 95%). In contrast to results with total rat liver mRNA, injection of mRNA derived from the Na+/bile acid cotransporter cDNA (Hagenbuch, B., B. Stieger, M. Foguet, H. Lübbert, and P. J. Meier. 1991. Proc. Natl. Acad. Sci. USA. In press.) had no effect on BSP uptake into oocytes. Size fractionation of total rat liver mRNA revealed that a 2.0- to 3.5-kb size-class mRNA was sufficient to express the hepatic chloride-dependent BSP uptake system. These data indicate that "expression cloning" in oocytes represents a promising approach to ultimately clone the cDNA coding for the hepatocyte high affinity, chloride-dependent organic anion uptake system. Furthermore, the results confirm that the Na+/bile acid cotransport system does not mediate BSP uptake. PMID:1752967

  11. Amino acids inhibit kynurenic acid formation via suppression of kynurenine uptake or kynurenic acid synthesis in rat brain in vitro.

    PubMed

    Sekine, Airi; Okamoto, Misaki; Kanatani, Yuka; Sano, Mitsue; Shibata, Katsumi; Fukuwatari, Tsutomu

    2015-01-01

    The tryptophan metabolite, kynurenic acid (KYNA), is a preferential antagonist of the α7 nicotinic acetylcholine receptor at endogenous brain concentrations. Recent studies have suggested that increase of brain KYNA levels is involved in psychiatric disorders such as schizophrenia and depression. KYNA-producing enzymes have broad substrate specificity for amino acids, and brain uptake of kynurenine (KYN), the immediate precursor of KYNA, is via large neutral amino acid transporters (LAT). In the present study, to find out amino acids with the potential to suppress KYNA production, we comprehensively investigated the effects of proteinogenic amino acids on KYNA formation and KYN uptake in rat brain in vitro. Cortical slices of rat brain were incubated for 2 h in Krebs-Ringer buffer containing a physiological concentration of KYN with individual amino acids. Ten out of 19 amino acids (specifically, leucine, isoleucine, phenylalanine, methionine, tyrosine, alanine, cysteine, glutamine, glutamate, and aspartate) significantly reduced KYNA formation at 1 mmol/L. These amino acids showed inhibitory effects in a dose-dependent manner, and partially inhibited KYNA production at physiological concentrations. Leucine, isoleucine, methionine, phenylalanine, and tyrosine, all LAT substrates, also reduced tissue KYN concentrations in a dose-dependent manner, with their inhibitory rates for KYN uptake significantly correlated with KYNA formation. These results suggest that five LAT substrates inhibit KYNA formation via blockade of KYN transport, while the other amino acids act via blockade of the KYNA synthesis reaction in brain. Amino acids can be a good tool to modulate brain function by manipulation of KYNA formation in the brain. This approach may be useful in the treatment and prevention of neurological and psychiatric diseases associated with increased KYNA levels.

  12. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  13. Increased brain uptake of gamma-aminobutyric acid in a rabbit model of hepatic encephalopathy

    SciTech Connect

    Bassett, M.L.; Mullen, K.D.; Scholz, B.; Fenstermacher, J.D.; Jones, E.A. )

    1990-03-01

    Transfer of the inhibitory neurotransmitter gamma-aminobutyric acid across the normal blood-brain barrier is minimal. One prerequisite for gamma-aminobutyric acid in plasma contributing to the neural inhibition of hepatic encephalopathy would be that increased transfer of gamma-aminobutyric acid across the blood-brain barrier occurs in liver failure. The aim of the present study was to determine if brain gamma-aminobutyric acid uptake is increased in rabbits with stage II-III (precoma) hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure. A modification of the Oldendorf intracarotid artery-injection technique was applied. (3H) gamma-aminobutyric acid, (14C) butanol, and 113mIn-labeled serum protein (transferrin) were injected simultaneously 4 s before decapitation. The ipsilateral brain uptake index of gamma-aminobutyric acid was determined from measurements of the 3 isotopes in 5 brain regions. Uncorrected or simple brain uptake indices of (3H) gamma-aminobutyric acid and (113mIn) transferrin were calculated using (14C) butanol as the highly extracted reference compound. The (113mIn) transferrin data were also used to correct the brain uptake index of (3H) gamma-aminobutyric acid for intravascular retention of (3H) gamma-aminobutyric acid. The methodology adopted minimized problems attributable to rapid (3H) gamma-aminobutyric acid metabolism, and slow brain washout and recirculation of the radiolabeled tracers. Both the uncorrected and corrected brain uptake indices of gamma-aminobutyric acid as well as the simple brain uptake index of transferrin were significantly increased in both stage II and III hepatic encephalopathy in all brain regions studied. Moreover, these brain uptake indices were significantly greater in stage III hepatic encephalopathy than in stage II hepatic encephalopathy.

  14. Elevated sacroilac joint uptake ratios in systemic lupus erythematosus

    SciTech Connect

    De Smet, A.A.; Mahmood, T.; Robinson, R.G.; Lindsley, H.B.

    1984-08-01

    Sacroiliac joint radiographs and radionuclide sacroiliac joint uptake ratios were obtained on 14 patients with active systemic lupus erythematosus. Elevated joint ratios were found unilaterally in two patients and bilaterally in seven patients when their lupus was active. In patients whose disease became quiescent, the uptake ratios returned to normal. Two patients had persistently elevated ratios with continued clinical and laboratory evidence of active lupus. Mild sacroiliac joint sclerosis and erosions were detected on pelvic radiographs in these same two patients. Elevated quantitative sacroiliac joint uptake ratios may occur as a manifestation of active systemic lupus erythematosus.

  15. Effects of hydrostatic pressure and temperature on the uptake and respiration of amino acids by a facultatively psychrophilic marine bacterium.

    NASA Technical Reports Server (NTRS)

    Paul, K. L.; Morita, R. Y.

    1971-01-01

    Studies of pressure and temperature effects on glutamic acid transport and utilization indicated that hydrostatic pressure and low temperature inhibit glutamate transport more than glutamate respiration. The effects of pressure on transport were reduced at temperatures near the optimum. Similar results were obtained for glycine, phenylalanine, and proline. Pressure effects on the transport systems of all four amino acids were reversible to some degree. Both proline and glutamic acid were able to protect their transport proteins against pressure damage. The data presented indicate that the uptake of amino acids by cells under pressure is inhibited, which is the cause of their inability to grow under pressure.

  16. Compensatory Root Water Uptake of Overlapping Root Systems

    NASA Astrophysics Data System (ADS)

    Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

    2015-12-01

    Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

  17. Uptake of Hypobromous Acid (HOBr) by Aqueous Sulfuric Acid Solutions: Low-Temperature Solubility and Reaction

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Michelsen, Rebecca R.; Ashbourn, Samatha F. M.; Rammer, Thomas A.; Golden, David M.

    2005-01-01

    Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45 - 70 wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H* = 10(exp 4) - 10(exp 7) mol/L/atm. H* is inversely dependent on temperature, with Delta H = -46.2 kJ/mol and Delta S = -106.2 J/mol/K for 55 - 70 wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into aqueous 45 wt% H2SO4, the solubility can be described by log H* = 3665/T - 10.63. For 55 - 70 wt% H2SO4, log H* = 2412/T - 5.55. At temperatures colder than approx. 213 K, the solubility of HOBr in 45 wt% H2SO4 is noticeably larger than in 70 wt% H2SO4. The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Our measurements indicate chemical reaction of HOBr upon uptake into aqueous sulfuric acid in the presence of other brominated gases followed by evolution of gaseous products including Br2O and Br2, particularly at 70 wt% H2SO4.

  18. An observing system simulation for Southern Ocean carbon dioxide uptake.

    PubMed

    Majkut, Joseph D; Carter, Brendan R; Frölicher, Thomas L; Dufour, Carolina O; Rodgers, Keith B; Sarmiento, Jorge L

    2014-07-13

    The Southern Ocean is critically important to the oceanic uptake of anthropogenic CO2. Up to half of the excess CO2 currently in the ocean entered through the Southern Ocean. That uptake helps to maintain the global carbon balance and buffers transient climate change from fossil fuel emissions. However, the future evolution of the uptake is uncertain, because our understanding of the dynamics that govern the Southern Ocean CO2 uptake is incomplete. Sparse observations and incomplete model formulations limit our ability to constrain the monthly and annual uptake, interannual variability and long-term trends. Float-based sampling of ocean biogeochemistry provides an opportunity for transforming our understanding of the Southern Ocean CO2 flux. In this work, we review current estimates of the CO2 uptake in the Southern Ocean and projections of its response to climate change. We then show, via an observational system simulation experiment, that float-based sampling provides a significant opportunity for measuring the mean fluxes and monitoring the mean uptake over decadal scales.

  19. Uptake and utilization of dissolved free amino acids by the brittlestar Microphiopholis gracillima (Say, 1852) (Echinodermata: Ophiuroidea) during disc regeneration

    SciTech Connect

    Clements, L.A.J.

    1988-01-01

    Dissolved organic material (DOM) may be especially important to marine organisms unable to feed due to lack of a digestive system, injury or autotomy. Disc autotomy by the brittlestar Microphiopholis gracillima includes loss of the gut and gonads, and precludes ingestion of particulate food by the animal until gut regeneration is complete. The influence of DOM on the rate of disc regeneration by autotomized M. gracillima was tested by incubating animals in artificial seawater containing different concentrations of amino acids. Rates of uptake of amino acids and excretion of amino acids, ammonia and urea by intact and regenerating M. gracillima individuals were quantified using high performance liquid chromatography. Uptake and catabolism of leucine and glycine were examined using radioisotopic techniques. Both intact and regenerating M. gracillima increased their uptake of {sup 14}C-glycine with starvation, but rates of uptake were higher for intact animals. Catabolism of leucine and glycine, as evidenced by release of labeled CO{sub 2}, was highest among intact animals indicating that the amino acids were being used as energy sources during starvation. However, regenerating animals catabolized less than 2% of the labeled glycine acquired from seawater.

  20. Fate and Uptake of Pharmaceuticals in Soil–Earthworm Systems

    PubMed Central

    2014-01-01

    Pharmaceuticals present a potential threat to soil organisms, yet our understanding of their fate and uptake in soil systems is limited. This study therefore investigated the fate and uptake of 14C-labeled carbamazepine, diclofenac, fluoxetine, and orlistat in soil–earthworm systems. Sorption coefficients increased in the order of carbamazepine < diclofenac < fluoxetine < orlistat. Dissipation of 14C varied by compound, and for orlistat, there was evidence of formation of nonextractable residues. Uptake of 14C was seen for all compounds. Depuration studies showed complete elimination of 14C for carbamazepine and fluoxetine treatments and partial elimination for orlistat and diclofenac, with greater than 30% of the 14C remaining in the tissue at the end of the experiment. Pore-water-based bioconcentration factors (BCFs), based on uptake and elimination of 14C, increased in the order carbamazepine < diclofenac < fluoxetine and orlistat. Liquid chromatography–tandem mass spectrometry and liquid chromatography–Fourier transform mass spectrometry indicated that the observed uptake in the fluoxetine and carbamazepine treatments was due to the parent compounds but that diclofenac was degraded in the test system so uptake was due to unidentifiable transformation products. Comparison of our data with outputs of quantitative structure−activity relationships for estimating BCFs in worms showed that these models tend to overestimate pharmaceutical BCFs so new models are needed. PMID:24762061

  1. Saturable uptake of indol-3yl-acetic Acid by maize roots.

    PubMed

    Martin, H V; Pilet, P E

    1986-07-01

    The uptake of 5-[(3)H]indol-3yl-acetic acid (IAA(*)) by segments of Zea mays L. roots was measured in the presence of nonradioactive indol-3yl-acetic acid (IAA degrees ) at different concentrations. IAA uptake was found to have a nonsaturable component and a saturable part with (at pH 5.0) an apparent K(m) of 0.285 micromolar and apparent V(max) 55.0 picomoles per gram fresh mass per minute. These results are consistent with those which might be expected for a saturable carrier capable of regulating IAA levels. High performance liquid chromatography analyses showed that very little metabolism of IAA(*) took place during 4 minute uptake experiments. Whereas nonsaturable uptake was similar for all 2 millimeter long segments prepared within the 2 to 10 millimeter region, saturable uptake was greatest for the 2 to 4 millimeter region. High levels of uptake by stelar (as compared with cortical) segments are partly attributable to the saturable carrier, and also to a high level of uptake by nonsaturable processes. The carrier may play an essential role in controlling IAA levels in maize roots, especially the accumulation of IAA in the apical region. The increase in saturable uptake toward the root tip may also contribute to the acropetal polarity of auxin transport.

  2. Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

    NASA Astrophysics Data System (ADS)

    Gioseffi, E.; de Neergaard, A.; Schjoerring, J. K.

    2012-04-01

    Soil-borne amino acids may constitute a source of nitrogen (N) for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly) and glutamine (Gln) by wheat roots and their interactions with nitrate (NO3-) and ammonium (NH4+) during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake, thereby resulting in similar total N uptake rates. Amino acids were enriched with double-labelled 15N and 13C, while NO3- and NH4+ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO3- and NH4+ did not differ from each other and were generally about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50% of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO3- did not affect glycine uptake, while the presence of glycine down-regulated NO3- uptake. The ratio between 13C and 15N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction between the uptake of inorganic and organic N.

  3. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid* #

    PubMed Central

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-01-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of 109Cd increased significantly, and higher 109Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the 109Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  4. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid.

    PubMed

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-02-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of (109)Cd increased significantly, and higher (109)Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the (109)Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd. PMID:23365009

  5. Improved cadmium uptake and accumulation in the hyperaccumulator Sedum alfredii: the impact of citric acid and tartaric acid.

    PubMed

    Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Peng, Hong-yun; Li, Ting-qiang

    2013-02-01

    The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils. Organic acid has been suggested to be involved in toxic metallic element tolerance, translocation, and accumulation in plants. The impact of exogenous organic acids on cadmium (Cd) uptake and translocation in the zinc (Zn)/Cd co-hyperaccumulator Sedum alfredii was investigated in the present study. By the addition of organic acids, short-term (2 h) root uptake of (109)Cd increased significantly, and higher (109)Cd contents in roots and shoots were noted 24 h after uptake, when compared to controls. About 85% of the (109)Cd taken up was distributed to the shoots in plants with citric acid (CA) treatments, as compared with 75% within controls. No such effect was observed for tartaric acid (TA). Reduced growth under Cd stress was significantly alleviated by low CA. Long-term application of the two organic acids both resulted in elevated Cd in plants, but the effects varied with exposure time and levels. The results imply that CA may be involved in the processes of Cd uptake, translocation and tolerance in S. alfredii, whereas the impact of TA is mainly on the root uptake of Cd.

  6. EFFECT OF HUMIC ACID ON UPTAKE AND TRANSFER OF COPPER FROM MICROBES TO CILIATES TO COPEPODS

    EPA Science Inventory

    This research is part of an ongoing project designed to determine the effect of humic acid on the uptake and transfer of metals by marine organisms at the lower end of the food chain. Binding affinities for Cu, Cd, Zn, and Cr to Suwannee River humic acid were determined at variou...

  7. Effect of exercise and obesity on skeletal muscle amino acid uptake

    SciTech Connect

    Friedman, J.E.

    1988-01-01

    To determine if amino acid uptake by muscle of the obese Zucker rat is impaired, epitrochlearis (EPI) and soleus strip (SOL) muscles from 32 pairs of female lean (Fa/-) and obese (fa/fa) Zucker rats were incubated using ({sup 14}C){alpha}-aminoisobutyric acid (AIB). Because contractile activity also influences amino acid uptake, the effect of acute endurance exercise on amino acid uptake by skeletal muscle from lean and obese rats was also studied. Muscle wet and dry weights were similar in lean and obese rats. However, both muscle protein content and concentration from obese rats were significantly reduced. In preliminary studies, pinning EPI at resting length during incubation significantly increased AIB uptake and reduced muscle water accumulation. AIB uptake was similar in stripped and intact SOL. Lean and obese rats were studied at rest or following a 1 hr treadmill run at 8% grade Muscles were pinned, and preincubated for 30 min at 37{degree}C in Krebs Ringer bicarbonate buffer (KRB) containing 5mM glucose under 95:5 O{sub 2}/CO{sub 2}, followed by 30, 60, 120, or 180 min of incubation in KRB with 0.5 mM AIB, ({sup 14}C)-AIB to measure amino acid, and ({sup 3}H)-inulin to determine extracellular water.

  8. Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

    NASA Astrophysics Data System (ADS)

    Gioseffi, E.; de Neergaard, A.; Schjoerring, J. K.

    2011-11-01

    Soil-borne amino acids may constitute a nitrogen (N) source for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly) and glutamine (Gln) by wheat roots and their interactions with nitrate (NO3-) and (NH4+) during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake. Amino acids were enriched with double-labelled 15N and 13C, while NO3- and NH4+ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO3- and NH4+ did not differ from each other and were about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50 % of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO3- did not affect glycine uptake, while the presence of glycine down-regulated NO3- uptake. The ratio between 13C and 15N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction between the uptake of inorganic and organic nitrogen.

  9. Uptake and Dissolution of Gaseous Ethanol in Sulfuric Acid

    NASA Technical Reports Server (NTRS)

    Michelsen, Rebecca R.; Staton, Sarah J. R.; Iraci, Laura T.

    2006-01-01

    The solubility of gas-phase ethanol (ethyl alcohol, CH3CH2OH, EtOH) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (209-237 K) and acid composition (39-76 wt % H2SO4). Ethanol is very soluble under these conditions: effective Henry's law coefficients, H*, range from 4 x 10(exp 4) M/atm in the 227 K, 39 wt % acid to greater than 10(exp 7) M/atm in the 76 wt % acid. In 76 wt % sulfuric acid, ethanol solubility exceeds that which can be precisely determined using the Knudsen cell technique but falls in the range of 10(exp 7)-10(exp 10) M/atm. The equilibrium concentration of ethanol in upper tropospheric/lower stratospheric (UT/LS) sulfate particles is calculated from these measurements and compared to other small oxygenated organic compounds. Even if ethanol is a minor component in the gas phase, it may be a major constituent of the organic fraction in the particle phase. No evidence for the formation of ethyl hydrogen sulfate was found under our experimental conditions. While the protonation of ethanol does augment solubility at higher acidity, the primary reason H* increases with acidity is an increase in the solubility of molecular (i.e., neutral) ethanol.

  10. Adaptive enhancement of amino acid uptake and exodus by thymic lymphocytes: influence of pH.

    PubMed

    Peck, W A; Rockwell, L H; Lichtman, M A

    1976-11-01

    Entry of certain free amino acids (alpha aminoisobutyric acid (AIB), alanine and proline), but not of leucine into rat thymic lymphocytes increased progressively when the cells were incubated in amino acid deficient medium. Actinomycin D, cycloheximide, or a high concentration of AIB abolished the time-related increase in AIB accumulation, whereas exposure to a high concentration of leucine had no effect. This phenomenon could not be attributed to a progressive alteration in the nature of the incubation medium nor to reduced transinhibition of AIB uptake. The exodus of AIB also increased with time, but to a smaller degree than AIB entry. Initial rates of AIB entry and exodus increased with increases in the pH of the incubation medium over the range 6.5-8.0. The effects of pH on entry and exodus were time-related, increasing progressively oveb nullified the magnified time related increments in AIB transport caused by prolonged incubation at pH 8.0. The influence of a given pH on transport of AIB decreased rapidly when the cells were transferred to medium of another pH, but this tendency diminished the longer the cells were exposed to the initial pH. pH influenced the entry of alanine and proline in the same fashion as that of AIB, but did not affect leucine entry. These results indicate that thymic lymphocytes exhibit adaptive enhancement in the accumulation of free amino acids that are transported largley by the A or alanine-preferring system, and that the adaptive process involves both entry and exodus. Moreover, alterations in pH modify entry and exodus of these same amino acids, profoundly affect the magnitude of time-released increases, and may induce fundamental changes in the mechanism(s) serving amino acid transport.

  11. Uptake of acidic and basic sugar derivatives in Lemna gibba G1

    SciTech Connect

    Sanz, A.; Ullrich, C.I. Institut fuer Botanik, Darmstadt )

    1989-08-01

    The uptake of acidic and basic sugar derivatives in Lemna gibba L. was studied. Uronic acids applied to the experimental solution induced a small decrease of the membrane potential. After incubation of the plants in a 0.1 millimolar solution of these substrates, no decrease in the concentration of reducing groups in the external solution was detected. Respiration increased by 31% with 50 millimolar galacturonic acid, whereas no effect was found with the same concentration of glucuronic acid. Glucosamine caused a considerable concentration-dependent membrane depolarization. ({sup 14}C)glucosamine uptake followed Michaelis-Menten kinetics together with a linear component. Influx of this substrate was inhibited by glucose but the type of competition could not be clearly distinguished. Glucosamine, 50 millimolar, inhibited the respiration rate by 30%. The glucosamine uptake was pH-dependent, with maximum uptake at around pH 7. Lack of enhancement of uptake by low pH as well as the permanent membrane depolarization suggest a uniport mechanism for the charged species of the substrate and an electroneutral diffusion of the uncharged species.

  12. Viscosity controls humidity dependence of N2O5 uptake to citric acid aerosol

    NASA Astrophysics Data System (ADS)

    Gržinić, G.; Bartels-Rausch, T.; Berkemeier, T.; Türler, A.; Ammann, M.

    2015-08-01

    The heterogeneous loss of dinitrogen pentoxide (N2O5) to aerosol particles has a significant impact on the night time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short lived radioactive tracer method we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH). The results show that citric acid exhibits lower reactivity than similar di- and polycarboxylic acids, with uptake coefficients between ~ 3 × 10-4-~ 3 × 10-3 depending on humidity (17-70 % RH). This humidity dependence can be explained by a changing viscosity and, hence, diffusivity in the organic matrix. Since the viscosity of highly concentrated citric acid solutions is not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics may be limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

  13. Atorvastatin Prevents Glutamate Uptake Reduction Induced by Quinolinic Acid Via MAPKs Signaling.

    PubMed

    Vandresen-Filho, S; Martins, W C; Bertoldo, D B; Rieger, D K; Maestri, M; Leal, R B; Tasca, C I

    2016-08-01

    Statins have been shown to promote neuroprotection in a wide range of neurological disorders. However, the mechanisms involved in such effects of statins are not fully understood. Quinolinic acid (QA) is a neurotoxin that induces seizures when infused in vivo and promotes glutamatergic excitotoxicity in the central nervous system. The aim of this study was to evaluate the putative glutamatergic mechanisms and the intracellular signaling pathways involved in the atorvastatin neuroprotective effects against QA toxicity. Atorvastatin (10 mg/kg) treatment for 7 days prevented the QA-induced decrease in glutamate uptake, but had no effect on increased glutamate release induced by QA. Moreover, atorvastatin treatment increased the phosphorylation of ERK1 and prevented the decrease in Akt phosphorylation induced by QA. Neither atorvastatin treatment nor QA infusion altered glutamine synthetase activity or the levels of phosphorylation of p38(MAPK) or JNK1/2 during the evaluation. Inhibition of MEK/ERK signaling pathway, but not PI3K/Akt signaling, abolished the neuroprotective effect of atorvastatin against QA-induced decrease in glutamate uptake. Our data suggest that atorvastatin protective effects against QA toxicity are related to modulation of glutamate transporters via MAPK/ERK signaling pathway.

  14. Effect of diet-induced obesity on kinetic parameters of amino acid uptake by rat erythrocytes.

    PubMed

    Picó, C; Pons, A; Palou, A

    1992-11-01

    The effects of cafeteria diet-induced obesity upon in vitro uptake of L-Alanine, Glycine, L-Lysine, L-Glutamine, L-Glutamic acid, L-Phenylalanine and L-Leucine by isolated rat erythrocytes have been studied. The total Phe and Leu uptakes followed Michaelis-Menten kinetics. The Glu uptake was fitted to diffusion kinetics. The uptakes of Ala, Gly, Lys and Gln were best explained by a two-component transport: one saturable and one diffusion. Obesity increased the Km value for Ala, Gln and Leu, and the Vmax value for Ala, but decreased the Vmax for Lys. Kinetic parameters of Phe uptake were unaffected by obesity. In addition, the pseudo-first order rate constant (Vmax/Km) for Ala, Gly, Gln, Lys and Leu uptake decreased as a result of cafeteria diet-induced obesity. The Kd value for Ala, Gly, Gln and Glu decreased and that of Lys increased as result of obesity. These adaptations could, at least in part, explain alterations in amino acid distribution between blood cells and plasma related to overfeeding or obesity.

  15. pH-Dependent Uptake of Fumaric Acid in Saccharomyces cerevisiae under Anaerobic Conditions

    PubMed Central

    Jamalzadeh, Elaheh; Verheijen, Peter J. T.; Heijnen, Joseph J.

    2012-01-01

    Microbial production of C4 dicarboxylic acids from renewable resources has gained renewed interest. The yeast Saccharomyces cerevisiae is known as a robust microorganism and is able to grow at low pH, which makes it a suitable candidate for biological production of organic acids. However, a successful metabolic engineering approach for overproduction of organic acids requires an incorporation of a proper exporter to increase the productivity. Moreover, low-pH fermentations, which are desirable for facilitating the downstream processing, may cause back diffusion of the undissociated acid into the cells with simultaneous active export, thereby creating an ATP-dissipating futile cycle. In this work, we have studied the uptake of fumaric acid in S. cerevisiae in carbon-limited chemostat cultures under anaerobic conditions. The effect of the presence of fumaric acid at different pH values (3 to 5) has been investigated in order to obtain more knowledge about possible uptake mechanisms. The experimental results showed that at a cultivation pH of 5.0 and an external fumaric acid concentration of approximately 0.8 mmol · liter−1, the fumaric acid uptake rate was unexpectedly high and could not be explained by diffusion of the undissociated form across the plasma membrane alone. This could indicate the presence of protein-mediated import. At decreasing pH levels, the fumaric acid uptake rate was found to increase asymptotically to a maximum level. Although this observation is in accordance with protein-mediated import, the presence of a metabolic bottleneck for fumaric acid conversion under anaerobic conditions could not be excluded. PMID:22113915

  16. Technetium-99m dimercaptosuccinic acid uptake in long-term catheterized kidney. Comparison with renal function

    SciTech Connect

    Higashihara, E.; Tokuda, H.; Kishi, H.; Niijima, T.; Okada, Y.; Nishikawa, J.; Iio, M.

    1988-04-01

    We studied 23 long-term catheterized kidneys in 14 patients. The uptake of /sup 99m/Tc acid (/sup 99m/Tc-DMSA) was measured at one- and two-hour intervals after injection, and the uptake was corrected for variations in renal depth. These values were compared with inulin, creatinine, and para-amino hippurate (PAH) clearances which were measured in each kidney by collecting urine through long-term catheterization. Correlation coefficient was obtained between PAH clearance corrected for the body surface area and the two-hour uptake of /sup 99m/Tc-DMSA. The correlation coefficients between the two-hour uptake of /sup 99m/Tc-DMSA and the clearance values are not significantly different from those between the one-hour uptake and the clearance values. Corrections of the uptake for variations in renal depth did not improve the correlation coefficients. The results show that /sup 99m/Tc-DMSA is an excellent method to estimate the renal plasma flow and the one-hour uptake without correction for renal depth is clinically sufficient to evaluate the split renal function.

  17. Retinoic acid treatment of fibroblasts causes a rapid decrease in ( sup 3 H)inositol uptake

    SciTech Connect

    Sinha, R.; Creek, K.E.; Silverman-Jones, C.; de Luca, L.M. )

    1989-04-01

    NIH 3T3 fibroblasts treated with all-trans-retinoic acid (RA) showed a dramatic decrease in the uptake of ({sup 3}H)inositol compared to solvent-treated controls. The onset of RA-induced inhibition of ({sup 3}H)inositol uptake was rapid with a 10-15% decrease occurring after 2-3 h of RA exposure and 60-70% reduction after 16 h of RA treatment. A progressive dose-dependent decrease in inositol uptake was found as the concentration of RA increased from 10{sup {minus}8} to 10{sup {minus}5} M and the effect was fully reversible within 48 h after RA removal. RA inhibition of inositol uptake was also observed in 3T3-Swiss and Balb/3T3 cells but not in two virally transformed 3T3 cell lines. Phlorizin, amiloride, and monensin inhibited inositol uptake by 66, 74, and 58%, respectively, and this inhibition was additive when the cells were treated with RA as well as these inhibitors. A decreased incorporation of ({sup 3}H)inositol into polyphosphoinositides was also observed in RA-treated cells but not to the same extent as for ({sup 3}H)inositol uptake. In conclusion, RA treatment of 3T3 fibroblasts decreases the uptake of ({sup 3}H)inositol by up to 70% within 8 to 10 h at near physiological concentrations in a reversible and specific manner.

  18. UPTAKE AND ELIMINATION OF DICHLOROACETIC ACID BY RAINBOW TROUT

    EPA Science Inventory

    Dichloroacetic acid (DCA) is a by-product of drinking water chlorination and is a hepatocarcinogen in rodents. Preliminary results of a chronic testing effort with Japanese medaka suggest the possibility of similar effects is fish. Adult rainbow trout were cannulated from the dor...

  19. Bile acid inhibition of taurocholate uptake by rat hepatocytes: role of OH groups

    SciTech Connect

    Bellentani, S.; Hardison, W.G.M.; Marchegiano, P.; Zanasi, G.; Manenti, F.

    1987-03-01

    To define further the structural specificity of the taurocholate uptake site, the authors studied the ability of a variety of taurine-conjugated bile acids with differing hydroxyl substituents on the sterol moiety to inhibit (/sup 14/C) taurocholate uptake. Rat hepatocytes isolated by collagenase perfusion were incubated in a tris (hydroxymethyl) aminomethane-phosphate buffer containing (/sup 14/C)taurocholate in the presence or absence of inhibitor bile acid. Stronger inhibitors were studied at a fixed concentration of 5 ..mu..M, weaker ones at 25 ..mu..M. Initial uptake velocity was measured. Uptake velocity could then be related to taurocholate concentration and a V/sub max/ and K/sub m/ could be determined by applying a nonlinear least squares fit to the data obtained with or without inhibitor. The kinetic parameters allowed the determination of the type of inhibition and of inhibition constants (K/sub i/) of the various test bile acids. The data indicate that bile acids containing a 6- or 7-OH group exhibit competitive inhibition, whereas bile acids with no 6- or 7-OH group exhibit noncompetitive inhibition. Of the compounds exhibiting competitive inhibition, K/sub i/ varied with the number of hydroxyl groups on the sterol moiety. They conclude that the presence of absence of a 6- or 7-OH group dictates the mechanism of inhibition; the number of hydroxyl substituents determines the potency of competitive inhibition.

  20. Dietary Medium Chain Fatty Acid Supplementation Leads to Reduced VLDL Lipolysis and Uptake Rates in Comparison to Linoleic Acid Supplementation

    PubMed Central

    van Schalkwijk, Daniël B.; Pasman, Wilrike J.; Hendriks, Henk F. J.; Verheij, Elwin R.; Rubingh, Carina M.; van Bochove, Kees; Vaes, Wouter H. J.; Adiels, Martin; Freidig, Andreas P.; de Graaf, Albert A.

    2014-01-01

    Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and linoleic acid activates PPAR receptors. Both these mechanisms may modify lipoprotein and fatty acid metabolism after dietary intervention. Our objective was to investigate how dietary MCFA and linoleic acid supplementation and body fat distribution affect the fasting lipoprotein subclass profile, lipoprotein kinetics, and postprandial fatty acid kinetics. In a randomized double blind cross-over trial, 12 male subjects (age 51±7 years; BMI 28.5±0.8 kg/m2), were divided into 2 groups according to waist-hip ratio. They were supplemented with 60 grams/day MCFA (mainly C8:0, C10:0) or linoleic acid for three weeks, with a wash-out period of six weeks in between. Lipoprotein subclasses were measured using HPLC. Lipoprotein and fatty acid metabolism were studied using a combination of several stable isotope tracers. Lipoprotein and tracer data were analyzed using computational modeling. Lipoprotein subclass concentrations in the VLDL and LDL range were significantly higher after MCFA than after linoleic acid intervention. In addition, LDL subclass concentrations were higher in lower body obese individuals. Differences in VLDL metabolism were found to occur in lipoprotein lipolysis and uptake, not production; MCFAs were elongated intensively, in contrast to linoleic acid. Dietary MCFA supplementation led to a less favorable lipoprotein profile than linoleic acid supplementation. These differences were not due to elevated VLDL production, but rather to lower lipolysis and uptake rates. PMID:25049048

  1. Effects of ammonium application rate on uptake of soil adsorbed amino acids by rice*

    PubMed Central

    Cao, Xiao-chuang; Ma, Qing-xu; Wu, Liang-huan; Zhu, Lian-feng; Jin, Qian-yu

    2016-01-01

    In recent years, excessive use of chemical nitrogen (N) fertilizers has resulted in the accumulation of excess ammonium (NH4 +) in many agricultural soils. Though rice is known as an NH4 +-tolerant species and can directly absorb soil intact amino acids, we still know considerably less about the role of high exogenous NH4 + content on rice uptake of soil amino acids. This experiment examined the effects of the exogenous NH4 + concentration on rice uptake of soil adsorbed glycine in two different soils under sterile culture. Our data showed that the sorption capacity of glycine was closely related to soils’ physical and chemical properties, such as organic matter and cation exchange capacity. Rice biomass was significantly inhibited by the exogenous NH4 + content at different glycine adsorption concentrations. A three-way analysis of variance demonstrated that rice glycine uptake and glycine nutritional contribution were not related to its sorption capacity, but significantly related to its glycine:NH4 + concentration ratio. After 21-d sterile cultivation, the rice uptake of adsorbed glycine accounted for 8.8%‒22.6% of rice total N uptake, which indicates that soil adsorbed amino acids theoretically can serve as an important N source for plant growth in spite of a high NH4 + application rate. However, further studies are needed to investigate the extent to which this bioavailability is realized in the field using the 13C, 15N double labeling technology.

  2. Nitric Acid Uptake on Subtropical Cirrus Cloud Particles

    NASA Technical Reports Server (NTRS)

    Popp, P. J.; Gao, R. S.; Marcy, T. P.; Fahey, D. W.; Hudson, P. K.; Thompson, T. L.; Kaercher, B.; Ridley, B. A.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D. D.; Baumgardner, D.; Garrett, T. J.; Weinstock, E. M.; Smith, J. B.; Sayres, D. S.; Pittman, J. V.; Dhaniyala, S.; Bui, T. P.; Mahoney, M. J.

    2004-01-01

    The redistribution of HNO3 via uptake and sedimentation by cirrus cloud particles is considered an important term in the upper tropospheric budget of reactive nitrogen. Numerous cirrus cloud encounters by the NASA WB-57F high-altitude research aircraft during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) were accompanied by the observation of condensed-phase HNO3 with the NOAA chemical ionization mass spectrometer. The instrument measures HNO3 with two independent channels of detection connected to separate forward and downward facing inlets that allow a determination of the amount of HNO3 condensed on ice particles. Subtropical cirrus clouds, as indicated by the presence of ice particles, were observed coincident with condensed-phase HNO3 at temperatures of 197-224 K and pressures of 122-224 hPa. Maximum levels of condensed-phase HNO3 approached the gas-phase equivalent of 0.8 ppbv. Ice particle surface coverages as high as 1.4 # 10(exp 14) molecules/ square cm were observed. A dissociative Langmuir adsorption model, when using an empirically derived HNO3 adsorption enthalpy of -11.0 kcal/mol, effectively describes the observed molecular coverages to within a factor of 5. The percentage of total HNO3 in the condensed phase ranged from near zero to 100% in the observed cirrus clouds. With volume-weighted mean particle diameters up to 700 ?m and particle fall velocities up to 10 m/s, some observed clouds have significant potential to redistribute HNO3 in the upper troposphere.

  3. Nitric Acid Uptake on Subtropical Cirrus Cloud Particles

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The redistribution of HNO3 via uptake and sedimentation by cirrus cloud particles is considered an important term in the upper tropospheric budget of reactive nitrogen. Numerous cirrus cloud encounters by the NASA WB-57F high-altitude research aircraft during CRYSTAL-FACE were accompanied by the observation of condensed-phase HNO3 with the NOAA chemical ionization mass spectrometer. The instrument measures HNO3 with two independent channels of detection connected to separate forward- and downward-facing inlets that allow a determination of the amount of HNO3 condensed on ice particles. Subtropical cirrus clouds, as indicated by the presence of ice particles, were observed coincident with condensed-phase HNO3 at temperatures of 197 K - 224 K and pressures of 122 hPa - 224 hPa. Maximum levels of condensed-phase HNO3 approached the gas-phase equivalent of 0.8 ppbv. Ice particle surface coverages as high as 1.4- 10(exp 14) molecules/sq cm were observed. A dissociative Langmuir adsorption model, when using an empirically derived HNO3 adsorption enthalpy of -11.0 kcal/mol, effectively describes the observed molecular coverages to within a factor of 5. The percentage of total HNO3 in the condensed phase ranged from near zero to 100% in the observed cirrus clouds. With volume-weighted mean particle diameters up to 700 pm and particle fall velocities up to 10 m/s, some observed clouds have significant potential to redistribute HNO3 in the upper troposphere.

  4. Stimulation of polyunsaturated fatty acid oxidation in myocytes by regulating its cellular uptake

    SciTech Connect

    Abdel-aleem, S.; Frangakis, C. ); Badr, M. )

    1991-01-01

    In order to investigate the regulation of polyunsaturated fatty acid oxidation in the heart, the effect of the phosphodiesterase inhibitor enoximone on the oxidation of (1-{sup 14}C) arachidonic acid, and (1-{sup 14}C) arachidonyl-CoA, were studied in adult rat myocytes, and isolated rat heart mitochondria. Enoximone stimulated arachidonate oxidation by 94%, at a concentration of 0.25 mM. The apparent Vmax value of archidonate oxidation in the presence of enoximone was approximately 75% higher than the value observed with the control in isolated myocytes. Also, enoximone stimulated arachidonate uptake by 27% at a concentration of 0.25 mM. On the other hand, enoximone had no effect on the oxidation of (1-{sup 14}C) arachidonyl-CoA in isolated rat heart mitochondria. These results suggest that the oxidation of polyunsaturated fatty acids in myocytes is regulated by the rate of uptake of these acids across sarcolemmal membranes.

  5. The role of citric acid in cadmium and nickel uptake and translocation, in Halimione portulacoides.

    PubMed

    Duarte, Bernardo; Delgado, Marta; Caçador, Isabel

    2007-10-01

    Some plants have high ability to absorb heavy metals in high concentrations. In this study, Halimione portulacoides was tested in conjunction with citric acid, in order to evaluate the possible use of this plant in phytoremediation processes in salt marshes. Two different concentrations of chelator were used combined with two heavy metal concentrations. When 25microM of citric acid was applied, Cd uptake and translocation was enhanced while for Ni these processes were almost inhibited. Increasing citric acid concentration to 50microM, Ni absorption decreased by the roots while for Cd there was still an increase in root uptake. Analysing translocation with this concentration of chelator, a decreased metal content in the upper organs for both metals was observed. While for Cd an optimal concentration of 25microM of citric acid was observed for phytoremediative processes, for nickel neither concentrations of chelator showed advantages for application in this remediative method. PMID:17585999

  6. Impact of Mistletoe Triterpene Acids on the Uptake of Mistletoe Lectin by Cultured Tumor Cells.

    PubMed

    Mulsow, Katharina; Enzlein, Thomas; Delebinski, Catharina; Jaeger, Sebastian; Seifert, Georg; Melzig, Matthias F

    2016-01-01

    Complementary treatment possibilities for the therapy of cancer are increasing in demand due to the severe side effects of the standard cytostatics used in the first-line therapy. A common approach as a complementary treatment is the use of aqueous extracts of Viscum album L. (Santalaceace). The therapeutic activity of these extracts is attributed to Mistletoe lectins which are Ribosome-inactivating proteins type II. Besides these main constituents the extract of Viscum album L. comprises also a mixture of lipophilic ingredients like triterpene acids of the oleanane, lupane and ursane type. However, these constituents are not contained in commercially available aqueous extracts due to their high lipophilicity and insolubility in aqueous extraction media. To understand the impact of the extract ingredients in cancer therapy, the intracellular uptake of the mistletoe lectin I (ML) by cultured tumor cells was investigated in relation to the mistletoe triterpene acids, mainly oleanolic acid. Firstly, these hydrophobic triterpene acids were solubilized using cyclodextrins ("TT" extract). Afterwards, the uptake of either single compounds (isolated ML and the aqueous "viscum" extract) or in combination with the TT extract (ML+TT, viscumTT), was analyzed. The uptake of ML was studied inTHP-1-, HL-60-, 143B- and Ewing TC-71-cells and determined after 30, 60 and 120 minutes by an enzyme linked immunosorbent assay which quantifies the A-chain of the hololectin. It could be shown that the intracellular uptake after 120 minutes amounted to 20% in all cell lines after incubation with viscumTT. The studies further revealed that the uptake in THP-1-, HL-60- and Ewing TC-71-cells was independent of the addition of TT extract. Interestingly, the uptake of ML by 143B-cells could only be measured after addition of triterpenes pointing to resistance to mistletoe lectin. PMID:27088729

  7. Impact of Mistletoe Triterpene Acids on the Uptake of Mistletoe Lectin by Cultured Tumor Cells

    PubMed Central

    Mulsow, Katharina; Enzlein, Thomas; Delebinski, Catharina; Jaeger, Sebastian; Seifert, Georg; Melzig, Matthias F.

    2016-01-01

    Complementary treatment possibilities for the therapy of cancer are increasing in demand due to the severe side effects of the standard cytostatics used in the first-line therapy. A common approach as a complementary treatment is the use of aqueous extracts of Viscum album L. (Santalaceace). The therapeutic activity of these extracts is attributed to Mistletoe lectins which are Ribosome-inactivating proteins type II. Besides these main constituents the extract of Viscum album L. comprises also a mixture of lipophilic ingredients like triterpene acids of the oleanane, lupane and ursane type. However, these constituents are not contained in commercially available aqueous extracts due to their high lipophilicity and insolubility in aqueous extraction media. To understand the impact of the extract ingredients in cancer therapy, the intracellular uptake of the mistletoe lectin I (ML) by cultured tumor cells was investigated in relation to the mistletoe triterpene acids, mainly oleanolic acid. Firstly, these hydrophobic triterpene acids were solubilized using cyclodextrins (“TT” extract). Afterwards, the uptake of either single compounds (isolated ML and the aqueous “viscum” extract) or in combination with the TT extract (ML+TT, viscumTT), was analyzed. The uptake of ML was studied inTHP-1-, HL-60-, 143B- and Ewing TC-71-cells and determined after 30, 60 and 120 minutes by an enzyme linked immunosorbent assay which quantifies the A-chain of the hololectin. It could be shown that the intracellular uptake after 120 minutes amounted to 20% in all cell lines after incubation with viscumTT. The studies further revealed that the uptake in THP-1-, HL-60- and Ewing TC-71-cells was independent of the addition of TT extract. Interestingly, the uptake of ML by 143B-cells could only be measured after addition of triterpenes pointing to resistance to mistletoe lectin. PMID:27088729

  8. Uptake and/or utilization of two simple phenolic acids by Cucumis sativus

    SciTech Connect

    Shann, J.R.

    1986-01-01

    The uptake of ferulic acid (FA) and p-hydroxybenzoic acid (p-HBA) from solutions (0.1 to 1.00 mM, pH 4.0 to 7.0), was determined for intact and excised roots of Cucumis sativus. Uptake methods based on high performance liquid chromatographic (HPLC) analysis of phenolic acid depletion from solution were compared to those radioisotopic methods employing (U-ring-/sup 14/C)FA or p-HBA. Although radiotracer methods more accurately reflected actual uptake of the compounds by cucumber seedlings, HPLC solution depletion methods may be useful in the elucidation of trends over very limited periods of time. The uptake of FA was unaffected by the presence of p-HBA. The uptake of p-HBA was reduced by 30% in the presence of FA when compared to the uptake from solutions containing p-HBA alone. Ferulic acid acts both as an allelopathic agent and precursor in the endogenous process of lignification. To evaluate the involvement of exogenous FA in lignin biosynthesis, roots of hydroponically grown cucumber seedlings were exposed to concentrations of FA labeled with (U-ring-/sup 14/C)FA. Radiotracer was distributed throughout the seedling. A quantitative change in lignification occurred in treated seedlings. In roots and stems, the level of lignin increased with the number of exposures and as the concentrations of exogenous FA increased. Radiotracer was found in the residues of lignin isolated from seedling tissue treated with (U-ring-/sup 14/C)FA. This suggested the utilization of the exogenously applied FA in the endogenous process of lignification.

  9. UPTAKE AND METABOLISM OF ALL-TRANS RETINOIC ACID BY THREE NATIVE NORTH AMERICAN RANIDS

    EPA Science Inventory

    Retinoids, which are Vvitamin A derivatives, are important signaling molecules that regulate processes critical for development in all vertebrates. The objective of our study was to examine uptake and metabolism of the model retinoid, all-trans retinoic acid (all-trans RA), by th...

  10. [Effect of cholinomimetics on L-glutamic acid release and uptake in the neostriatum of rats].

    PubMed

    Godukhin, O V; Budantsev, A Iu; Selifonova, O V; Agapova, V N

    1983-12-01

    The effects of cholinomimetics on release and uptake of exogenic glutamic acid in the rat brain neostriatum in vivo and in vitro were studied. Carbocholine and nicotin were shown to inhibit the release, carbocholine acting directly on the presynaptic receptors whereas nicotin acting indirectly through the interneurons of neostriatum. PMID:6141074

  11. Assessing amino acid uptake by phototrophic nanoflagellates in nonaxenic cultures using flow cytometric sorting.

    PubMed

    Hartmann, Manuela; Zubkov, Mikhail V; Martin, Adrian P; Scanlan, David J; Burkill, Peter H

    2009-09-01

    Biologically available concentrations of individual dissolved amino acids in the open ocean are generally <1 nM. Despite this, the microbial turnover of amino acids is usually measured in hours indicating high demand. It is thought that the majority of uptake is due to bacterioplankton, although protists, particularly phototrophic protists, are also expected to take up amino acids. In order to assess the ability of protists to compete with prokaryotes for amino acids at subnanomolar concentrations, we examined the direct uptake of (3)H-leucine by phototrophic nanoflagellates (prasinophytes, pelagophytes and trebouxiophytes) and by associated bacteria using flow cytometric cell sorting. In contrast to (3)H-leucine-assimilating bacterial copopulations, none of the six studied nanoflagellates showed measurable direct uptake of (3)H-leucine, suggesting that the studied phototrophic protists were unable to utilize dissolved (3)H-leucine at natural oceanic concentrations. More practically, the flow-sorting technique allowed rapid and unequivocal differentiation of organic nitrogen uptake between prokaryotic cells and eukaryotic cells in mixed microbial populations, reducing the need to establish and maintain axenic algal cultures.

  12. The effect of central chemical sympathectomy on the oxygen uptake; anaerobic glycolysis and lactic acid dehydrogenase activity in the retina of white rats.

    PubMed

    Pojda, S M; Brus, R

    1976-01-01

    Male Wistar rats were injected intraventricularly with two doses of 250 mcg of 6-hydroxydopamine (6-OHDA) in two consecutive days. Two weeks later the oxygen uptake, anaerobic glycolysis and lactic acid dehydrogenase (LDH) activity in the retina were determined. The decrease of oxygen uptake (-28%), anaerobic glycolysis (-31%) and LDH activity (-12%) in rats treated with 6-OHDA in comparison to control animals was found. The possible role of the adrenergic system in regulation of the metabolism of the retina is discussed.

  13. Plant-uptake of uranium: Hydroponic and soil system studies

    USGS Publications Warehouse

    Ramaswami, A.; Carr, P.; Burkhardt, M.

    2001-01-01

    Limited information is available on screening and selection of terrestrial plants for uptake and translocation of uranium from soil. This article evaluates the removal of uranium from water and soil by selected plants, comparing plant performance in hydroponic systems with that in two soil systems (a sandy-loam soil and an organic-rich soil). Plants selected for this study were Sunflower (Helianthus giganteus), Spring Vetch (Vicia sativa), Hairy Vetch (Vicia villosa), Juniper (Juniperus monosperma), Indian Mustard (Brassica juncea), and Bush Bean (Phaseolus nanus). Plant performance was evaluated both in terms of the percent uranium extracted from the three systems, as well as the biological absorption coefficient (BAC) that normalized uranium uptake to plant biomass. Study results indicate that uranium extraction efficiency decreased sharply across hydroponic, sandy and organic soil systems, indicating that soil organic matter sequestered uranium, rendering it largely unavailable for plant uptake. These results indicate that site-specific soils must be used to screen plants for uranium extraction capability; plant behavior in hydroponic systems does not correlate well with that in soil systems. One plant species, Juniper, exhibited consistent uranium extraction efficiencies and BACs in both sandy and organic soils, suggesting unique uranium extraction capabilities.

  14. The role of L-type amino acid transporters in the uptake of glyphosate across mammalian epithelial tissues.

    PubMed

    Xu, Jiaqiang; Li, Gao; Wang, Zhuoyi; Si, Luqin; He, Sijie; Cai, Jialing; Huang, Jiangeng; Donovan, Maureen D

    2016-02-01

    Glyphosate is one of the most commonly used herbicides worldwide due to its broad spectrum of activity and reported low toxicity to humans. Glyphosate has an amino acid-like structure that is highly polar and shows low bioavailability following oral ingestion and low systemic toxicity following intravenous exposures. Spray applications of glyphosate in agricultural or residential settings can result in topical or inhalation exposures to the herbicide. Limited systemic exposure to glyphosate occurs following skin contact, and pulmonary exposure has also been reported to be low. The results of nasal inhalation exposures, however, have not been evaluated. To investigate the mechanisms of glyphosate absorption across epithelial tissues, the permeation of glyphosate across Caco-2 cells, a gastrointestinal epithelium model, was compared with permeation across nasal respiratory and olfactory tissues excised from cows. Saturable glyphosate uptake was seen in all three tissues, indicating the activity of epithelial transporters. The uptake was shown to be ATP and Na(+) independent, and glyphosate permeability could be significantly reduced by the inclusion of competitive amino acids or specific LAT1/LAT2 transporter inhibitors. The pattern of inhibition of glyphosate permeability across Caco-2 and nasal mucosal tissues suggests that LAT1/2 play major roles in the transport of this amino-acid-like herbicide. Enhanced uptake into the epithelial cells at barrier mucosae, including the respiratory and gastrointestinal tracts, may result in more significant local and systemic effects than predicted from glyphosate's passive permeability, and enhanced uptake by the olfactory mucosa may result in further CNS disposition, potentially increasing the risk for brain-related toxicities. PMID:26701683

  15. The role of L-type amino acid transporters in the uptake of glyphosate across mammalian epithelial tissues.

    PubMed

    Xu, Jiaqiang; Li, Gao; Wang, Zhuoyi; Si, Luqin; He, Sijie; Cai, Jialing; Huang, Jiangeng; Donovan, Maureen D

    2016-02-01

    Glyphosate is one of the most commonly used herbicides worldwide due to its broad spectrum of activity and reported low toxicity to humans. Glyphosate has an amino acid-like structure that is highly polar and shows low bioavailability following oral ingestion and low systemic toxicity following intravenous exposures. Spray applications of glyphosate in agricultural or residential settings can result in topical or inhalation exposures to the herbicide. Limited systemic exposure to glyphosate occurs following skin contact, and pulmonary exposure has also been reported to be low. The results of nasal inhalation exposures, however, have not been evaluated. To investigate the mechanisms of glyphosate absorption across epithelial tissues, the permeation of glyphosate across Caco-2 cells, a gastrointestinal epithelium model, was compared with permeation across nasal respiratory and olfactory tissues excised from cows. Saturable glyphosate uptake was seen in all three tissues, indicating the activity of epithelial transporters. The uptake was shown to be ATP and Na(+) independent, and glyphosate permeability could be significantly reduced by the inclusion of competitive amino acids or specific LAT1/LAT2 transporter inhibitors. The pattern of inhibition of glyphosate permeability across Caco-2 and nasal mucosal tissues suggests that LAT1/2 play major roles in the transport of this amino-acid-like herbicide. Enhanced uptake into the epithelial cells at barrier mucosae, including the respiratory and gastrointestinal tracts, may result in more significant local and systemic effects than predicted from glyphosate's passive permeability, and enhanced uptake by the olfactory mucosa may result in further CNS disposition, potentially increasing the risk for brain-related toxicities.

  16. Viscosity controls humidity dependence of N2O5 uptake to citric acid aerosol

    NASA Astrophysics Data System (ADS)

    Gržinić, G.; Bartels-Rausch, T.; Berkemeier, T.; Türler, A.; Ammann, M.

    2015-12-01

    The heterogeneous loss of dinitrogen pentoxide (N2O5) to aerosol particles has a significant impact on the night-time nitrogen oxide cycle and therefore the oxidative capacity in the troposphere. Using a 13N short-lived radioactive tracer method, we studied the uptake kinetics of N2O5 on citric acid aerosol particles as a function of relative humidity (RH). The results show that citric acid exhibits lower reactivity than similar dicarboxylic and polycarboxylic acids, with uptake coefficients between ∼ 3 × 10-4-∼ 3 × 10-3 depending on humidity (17-70 % RH). At RH above 50 %, the magnitude and the humidity dependence can be best explained by the viscosity of citric acid as compared to aqueous solutions of simpler organic and inorganic solutes and the variation of viscosity with RH and, hence, diffusivity in the organic matrix. Since the diffusion rates of N2O5 in highly concentrated citric acid solutions are not well established, we present four different parameterizations of N2O5 diffusivity based on the available literature data or estimates for viscosity and diffusivity of H2O. Above 50 % RH, uptake is consistent with the reacto-diffusive kinetic regime whereas below 50 % RH, the uptake coefficient is higher than expected from hydrolysis of N2O5 within the bulk of the particles, and the uptake kinetics is most likely limited by loss on the surface only. This study demonstrates the impact of viscosity in highly oxidized and highly functionalized secondary organic aerosol material on the heterogeneous chemistry of N2O5 and may explain some of the unexpectedly low loss rates to aerosol derived from field studies.

  17. Fate and Uptake of Pharmaceuticals in Soil–Plant Systems

    PubMed Central

    2014-01-01

    Pharmaceuticals have been detected in the soil environment where there is the potential for uptake into crops. This study explored the fate and uptake of pharmaceuticals (carbamazepine, diclofenac, fluoxetine, propranolol, sulfamethazine) and a personal care product (triclosan) in soil–plant systems using radish (Raphanus sativus) and ryegrass (Lolium perenne). Five of the six chemicals were detected in plant tissue. Carbamazepine was taken up to the greatest extent in both the radish (52 μg/g) and ryegrass (33 μg/g), whereas sulfamethazine uptake was below the limit of quantitation (LOQ) (<0.01 μg/g). In the soil, concentrations of diclofenac and sulfamethazine dropped below the LOQ after 7 days. However, all pharmaceuticals were still detectable in the pore water at the end of the experiment. The results demonstrate the ability of plant species to accumulate pharmaceuticals from soils with uptake apparently specific to both plant species and chemical. Results can be partly explained by the hydrophobicity and extent of ionization of each chemical in the soil. PMID:24405013

  18. Increased physical activity decreases hepatic free fatty acid uptake: a study in human monozygotic twins

    PubMed Central

    Hannukainen, Jarna C; Nuutila, Pirjo; Ronald, Borra; Kaprio, Jaakko; Kujala, Urho M; Janatuinen, Tuula; Heinonen, Olli J; Kapanen, Jukka; Viljanen, Tapio; Haaparanta, Merja; Rönnemaa, Tapani; Parkkola, Riitta; Knuuti, Juhani; Kalliokoski, Kari K

    2007-01-01

    Exercise is considered to be beneficial for free fatty acid (FFA) metabolism, although reports of the effects of increased physical activity on FFA uptake and oxidation in different tissues in vivo in humans have been inconsistent. To investigate the heredity-independent effects of physical activity and fitness on FFA uptake in skeletal muscle, the myocardium, and liver we used positron emission tomography (PET) in nine healthy young male monozygotic twin pairs discordant for physical activity and fitness. The cotwins with higher physical activity constituting the more active group had a similar body mass index but less body fat and 18 ± 10% higher V˙O2,max (P < 0.001) compared to the less active brothers with lower physical activity. Low-intensity knee-extension exercise increased skeletal muscle FFA and oxygen uptake six to 10 times compared to resting values but no differences were observed between the groups at rest or during exercise. At rest the more active group had lower hepatic FFA uptake compared to the less active group (5.5 ± 4.3 versus 9.0 ± 6.1 μmol (100 ml)−1 min−1, P = 0.04). Hepatic FFA uptake associated significantly with body fat percentage (P = 0.05). Myocardial FFA uptake was similar between the groups. In conclusion, in the absence of the confounding effects of genetic factors, moderately increased physical activity and aerobic fitness decrease body adiposity even in normal-weighted healthy young adult men. Further, increased physical activity together with decreased intra-abdominal adiposity seems to decrease hepatic FFA uptake but has no effects on skeletal muscle or myocardial FFA uptake. PMID:17053033

  19. Uptake of 4-chloro-2-methylphenoxyacetic acid (MCPA) from the apical membrane of Caco-2 cells by the monocarboxylic acid transporter

    SciTech Connect

    Kimura, Osamu; Tsukagoshi, Kensuke; Endo, Tetsuya

    2008-03-15

    The cellular uptake mechanism of 4-chloro-2-methylphenoxyacetic acid (MCPA), a phenoxyacetic acid derivative, was investigated using Caco-2 epithelial cells. The cells were incubated with 50 {mu}M MCPA at pH 6.0 and 37 deg. C, and the uptake of MCPA from the apical membranes was measured. The uptake of MCPA was significantly decreased by incubation at low temperature (4 {sup o}C) and markedly increased by lowering the extracellular pH. Pretreatment with a protonophore, carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (25 {mu}M), or metabolic inhibitors, 2,4-dinitrophenol (1 mM) and sodium azide (10 mM), significantly decreased the uptake of MCPA by 53%, 45% and 48%, respectively. Coincubation of MCPA with 10 mM L-lactic acid or {alpha}-cyano-4-hydroxycinnamate, which is a substrate or an inhibitor of the monocarboxylic acid transporters (MCTs), significantly decreased the uptake of MCPA by 31% and 20%, respectively, and coincubation with benzoic acid profoundly decreased the uptake by 68%. In contrast, coincubation with succinic acid (a dicarboxylic acid) did not affect the uptake. Kinetic analysis of initial MCPA uptake suggested that MCPA is taken up via a carrier-mediated process [K{sub m} = 1.37 {+-} 0.15 mM, V{sub max} = 115 {+-} 6 nmol (mg protein){sup -1} (3 min){sup -1}]. Lineweaver-Burk plots show that benzoic acid competitively inhibits the uptake of MCPA with a K{sub i} value of 4.68 {+-} 1.76 mM. A trans-stimulation effect on MCPA uptake was found in cells preloaded with benzoic acid. These results suggest that the uptake of MCPA from the apical membrane of Caco-2 cells is mainly mediated by common MCTs along with benzoic acid but also in part by L-lactic acid.

  20. Insulin effect on amino acid uptake by unloaded rat hindlimb muscles

    NASA Technical Reports Server (NTRS)

    Jaspers, S. R.; Tischler, M. E.

    1988-01-01

    The effect of insulin on the uptake of alpha-amino-isobutyric acid (AIB) by unloaded rat hindlimb muscles was investigated using soleus and extensor digitorum longus (EDL) muscles from intact and adrenalectomized (ADX) rats that were tail-casted for six days. It was found that, at insulin levels above 0.00001 units/ml, the in vitro rate of AIB uptake by muscles from intact animals was stimulated more in the weight bearing muscles than in unloaded ones. In ADX animals, this differential response to insulin was abolished.

  1. Uptake of 13N-labeled N2O5 to citric acid aerosol particles

    NASA Astrophysics Data System (ADS)

    Grzinic, Goran; Bartels-Rausch, Thorsten; Birrer, Mario; Türler, Andreas; Ammann, Markus

    2013-04-01

    Dinitrogen pentoxide is a significant reactive intermediate in the night time chemistry of nitrogen oxides. Depending on atmospheric conditions it can act either as a NO3 radical reservoir or as a major NOx sink by heterogeneous hydrolysis on aerosol surfaces. As such, it can influence tropospheric ozone production and therefore the oxidative capacity of the atmosphere. Furthermore it's suspected of being a non negligible source of tropospheric Cl, even over continental areas [1,2]. We used the short-lived radioactive tracer 13N delivered by PSI's PROTRAC facility [3] in conjunction with an aerosol flow tube reactor in order to study N2O5 uptake kinetics on aerosol particles. 13NO is mixed with non labeled NO and O3 in a gas reactor where N2O5 is synthesized under dry conditions to prevent hydrolysis on the reactor walls. The resulting N2O5 flow is fed into an aerosol flow tube reactor together with a humidified aerosol flow. By using movable inlets we can vary the length of the aerosol flow tube and thus the reaction time. The gas feed from the reactor is then directed into a narrow parallel plate diffusion denuder system that allows for selective separation of the gaseous species present in the gas phase. Aerosol particles are trapped on a particle filter placed at the end of the denuder system. The activity of 13N labeled species trapped on the denuder plates and in the particle filter can be monitored via scintillation counters. Aerosol uptake measurements were performed with citric acid aerosols in a humidity range of 27-61.5% RH. The results obtained from our measurements have shown that the uptake coefficient increases with humidity from 1.65±0.3x10-3 (~27% RH) to 1.25±0.3x10-2 (45% RH) and 2.00±0.3x10-2 (61.5% RH). Comparison to literature data shows that this is similar to values reported for some polycarboxylic acids (like malonic acid), while being higher than some others [4]. The increase is likely related to the increasing amount of water associated

  2. Relationship of Cell Sap pH to Organic Acid Change During Ion Uptake 1

    PubMed Central

    Hiatt, A. J.

    1967-01-01

    Excised roots of barley (Hordeum vulgare, var. Campana) were incubated in KCl, K2SO4, CaCl2, and NaCl solutions at concentrations of 10−5 to 10−2 n. Changes in substrate solution pH, cell sap pH, and organic acid content of the roots were related to differences in cation and anion absorption. The pH of expressed sap of roots increased when cations were absorbed in excess of anions and decreased when anions were absorbed in excess of cations. The pH of the cell sap shifted in response to imbalances in cation and anion uptake in salt solutions as dilute as 10−5 n. Changes in cell sap pH were detectable within 15 minutes after the roots were placed in 10−3 n K2SO4. Organic acid changes in the roots were proportional to expressed sap pH changes induced by unbalanced ion uptake. Changes in organic acid content in response to differential cation and anion uptake appear to be associated with the low-salt component of ion uptake. PMID:16656506

  3. Uptake of Small Organic Compounds by Sulfuric Acid Aerosols: Dissolution and Reaction

    NASA Technical Reports Server (NTRS)

    Iraci, L. T.; Michelsen, R. R.; Ashbourn, S. F. M.; Staton, S. J. R.

    2003-01-01

    To assess the role of oxygenated volatile organic compounds in the upper troposphere and lower stratosphere, the interactions of a series of small organic compounds with low-temperature aqueous sulfuric acid will be evaluated. The total amount of organic material which may be taken up from the gas phase by dissolution, surface layer formation, and reaction during the particle lifetime will be quantified. Our current results for acetaldehyde uptake on 40 - 80 wt% sulfuric acid solutions will be compared to those of methanol, formaldehyde, and acetone to investigate the relationships between chemical functionality and heterogeneous activity. Where possible, equilibrium uptake will be ascribed to component pathways (hydration, protonation, etc.) to facilitate evaluation of other species not yet studied in low temperature aqueous sulfuric acid.

  4. Steric hindrance of 2,6-disubstituted benzoic acid derivatives on the uptake via monocarboxylic acid transporters from the apical membranes of Caco-2 cells.

    PubMed

    Tsukagoshi, Kensuke; Kimura, Osamu; Endo, Tetsuya

    2014-05-01

    Benzoic acid is a typical substrate for monocarboxylic acid transporters (MCTs), and easily taken up from the apical membranes of Caco-2 cells by MCTs. However, some benzoic acid derivatives were sparingly taken up by Caco-2 cells. To elucidate the mechanism of lower uptake of the derivatives, we investigated the effect of substitution of benzene ring on the uptake by MCTs using Caco-2 cells. Among the benzoic acid derivatives tested, the uptake of 2,6-disubstituted benzoic acids was markedly lower than that of other benzoic acids. Co-incubation of the 2,6-disubstituted derivatives with benzoic acid did not decrease the uptake of benzoic acid, while co-incubation with other derivatives significantly decreased the uptake of benzoic acid. Kinetic analyses elucidated that the uptake of 2,6-dichlorobenzoic acid and 2,3,6-trichlorobenzoic acid did not involve the carrier-mediated process. The 2,6-disubstitution of benzoic acid may prevent the access of carboxylic acid group to MCTs expressed on the apical membranes of Caco-2 cells. PMID:24861932

  5. Effect of dietary fatty acids on jejunal and ileal oleic acid uptake by rat brush border membrane vesicles.

    PubMed

    Prieto, R M; Stremmel, W; Sales, C; Tur, J A

    1996-04-18

    To test the effect of dietary fatty acids on fatty acid uptake, the influx kinetics of a representative long-chain fatty acid, 3H-oleic acid, in both the jejunum and ileum of rats has been studied using brush border membrane vesicles (BBMV). Animals were fed with semipurified diets containing 5 g fat/100 g diet, as corn oil (control group), safflower oil (unsaturated group) and coconut oil hydrogenated (saturated group). With increasing unbound oleate concentration in the medium, the three dietary groups showed saturable kinetics in both jejunal and ileal BBMV (controls: Vmax = 0.15 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 136 +/- 29.1 nmol for jejunum, and Vmax = 0.23 +/- 0.03 nmol x mg protein-1 x 5 min-1 and Km = 196 +/- 50.3 nmol for ileum; unsaturated: Vmax = 0.28 +/- 0.05 nmol x mg protein-1 x 5 min-1 and Km = 242.7 +/- 91.8 nmol for jejunum, and Vmax = 1.29 +/- 0.06 nmol x mg protein-1 x 5 min-1 and Km = 509.8 +/- 97.5 nmol for ileum; saturated: Vmax = 0.03 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 124.5 +/- 72.6 nmol for jejunum, and Vmax = 0.04 +/- 0.01 nmol x mg protein -1.5 min-1 and Km = 205.6 +/- 85.3 nmol for ileum). These results support the theory that feeding an isocaloric diet containing only unsaturated fatty acids enhanced oleic acid uptake, and feeding an isocaloric diet containing only saturated fatty acids decreased oleic acid uptake. The results obtained in the present work also show the adaptative ability of jejunum and ileum to the type of dietary fat.

  6. Structure-dependent effects of pyridine derivatives on mechanisms of intestinal fatty acid uptake: regulation of nicotinic acid receptor and fatty acid transporter expression.

    PubMed

    Riedel, Annett; Lang, Roman; Rohm, Barbara; Rubach, Malte; Hofmann, Thomas; Somoza, Veronika

    2014-07-01

    Pyridines are widely distributed in foods. Nicotinic acid (NA), a carboxylated pyridine derivative, inhibits lipolysis in adipocytes by activation of the orphan NA receptor (HM74A) and is applied to treat hyperlipidemia. However, knowledge on the impact of pyridine derivatives on intestinal lipid metabolism is scarce. This study was performed to identify the structural determinants of pyridines for their effects on fatty acid uptake in enterocyte-like Caco-2 cells and to elucidate the mechanisms of action. The impact of 17 pyridine derivatives on fatty acid uptake was tested. Multiple regression analysis revealed the presence of a methyl group to be the structural determinant at 0.1 mM, whereas at 1 mM, the presence of a carboxylic group and the N-methylation presented further structural characteristics to affect the fatty acid uptake. NA, showing a stimulating effect on FA uptake, and N-methyl-4-phenylpyridinium (MPP), inhibiting FA uptake, were selected for mechanistic studies. Gene expression of the fatty acid transporters CD36, FATP2 and FATP4, and the lipid metabolism regulating transcription factors peroxisome proliferator-activated receptor (PPAR) α and PPARγ was up-regulated upon NA treatment. Caco-2 cells were demonstrated to express the low-affinity NA receptor HM74 of which the gene expression was up-regulated upon NA treatment. We hypothesize that the NA-induced fatty acid uptake might result from NA receptor activation and related intracellular signaling cascades. In contrast, MPP increased transepithelial electrical resistance. We therefore conclude that NA and MPP, both sharing the pyridine motif core, exhibit their contrary effects on intestinal FA uptake by activation of different mechanisms.

  7. Structure-dependent effects of pyridine derivatives on mechanisms of intestinal fatty acid uptake: regulation of nicotinic acid receptor and fatty acid transporter expression.

    PubMed

    Riedel, Annett; Lang, Roman; Rohm, Barbara; Rubach, Malte; Hofmann, Thomas; Somoza, Veronika

    2014-07-01

    Pyridines are widely distributed in foods. Nicotinic acid (NA), a carboxylated pyridine derivative, inhibits lipolysis in adipocytes by activation of the orphan NA receptor (HM74A) and is applied to treat hyperlipidemia. However, knowledge on the impact of pyridine derivatives on intestinal lipid metabolism is scarce. This study was performed to identify the structural determinants of pyridines for their effects on fatty acid uptake in enterocyte-like Caco-2 cells and to elucidate the mechanisms of action. The impact of 17 pyridine derivatives on fatty acid uptake was tested. Multiple regression analysis revealed the presence of a methyl group to be the structural determinant at 0.1 mM, whereas at 1 mM, the presence of a carboxylic group and the N-methylation presented further structural characteristics to affect the fatty acid uptake. NA, showing a stimulating effect on FA uptake, and N-methyl-4-phenylpyridinium (MPP), inhibiting FA uptake, were selected for mechanistic studies. Gene expression of the fatty acid transporters CD36, FATP2 and FATP4, and the lipid metabolism regulating transcription factors peroxisome proliferator-activated receptor (PPAR) α and PPARγ was up-regulated upon NA treatment. Caco-2 cells were demonstrated to express the low-affinity NA receptor HM74 of which the gene expression was up-regulated upon NA treatment. We hypothesize that the NA-induced fatty acid uptake might result from NA receptor activation and related intracellular signaling cascades. In contrast, MPP increased transepithelial electrical resistance. We therefore conclude that NA and MPP, both sharing the pyridine motif core, exhibit their contrary effects on intestinal FA uptake by activation of different mechanisms. PMID:24767308

  8. Poor Tc-99m dimercaptosuccinic acid uptake, re-evaluation with Tc-99m MAG3 scintigraphy in Lowe syndrome

    PubMed Central

    Koca, Gokhan; Atilgan, Hasan Ikbal; Demirel, Koray; Diri, Akif; Korkmaz, Meliha

    2011-01-01

    Tc-99m dimercaptosuccinic acid (DMSA) is filtered through the glomeruli and reabsorbed by the proximal tubules as low molecular weight proteins. In Lowe syndrome this mechanism is impaired and so poor DMSA uptake is seen. Poor DMSA uptake was shown in very few studies, but none mentioned normal Tc-99m MAG3 uptake. In this case, the patient had poor DMSA uptake, normal MAG3 uptake and a neurogenic bladder in anterior to the left kidney that attenuates left kidney. PMID:23559713

  9. An exponential relationship exists between fatty acid uptake and myocardial blood flow

    SciTech Connect

    Sloof, G.W.; Comans, E.F.I.; Visser, F.C.

    1997-05-01

    High lineair (lin) correlations have been reported between myocardial blood flow (MBF) and uptake of various fatty acid (FA) analogues. However, the positive intercept with the Y-axis is not physiologically explainable (FA uptake without flow). This study investigates the appropriateness of an exponential (exp) model function. Methods: In 10 open-chest dogs the left anterior descending coronary artery was cannulated and extra corporally bypass perfused at reduced flow. MBF was assessed with scandium-46 labeled microspheres. 40 Minutes after iv. injection of 37 MBq 15-(p-[I-125]-iodophenyl)-3,3-dirnethylpentadecanoic acid (DMIPP), the heart was excised and cut into 120 samples. In each sample MBF (ml/g*min) and DMIPP uptake were assessed.In each dog, MBF and DMIPP uptake data were normalized to die respective means of the normally perfused myocardium. Uptake data were fitted to an exp model A[1-exp(-MBF/Fc)] by adjusting the flow constant Fc for minimal residual variance and adapting the amplitude A to obtain a zero mean residual error. The goodness of each fit was expressed by the standard error of the estimate (SEE). The mean SEE of the 10 dogs was 0.12{+-}0.04 with the exp fit and 0.24{+-}0.07 with the lin fit: p<0.001, F-test. For pooled data, the SEE was 0.15 with the exp fit and 0.26 with the lin fit (fig). Lin fit without zero intercept revealed a SEE of 0.18, which is higher than the SEE of the exp fit. The intercept was 0.54. Conclusion: In the normal to low MBF range, uptake of (methyl branched) FA analogues shows an exponential relationship, which is more appropriate than a linear relationship from a physiological point of view.

  10. Uptake and metabolism of 12-hydroxyeicosatetraenoic acid (12-HETE) by cultured renal tubular epithelial cells (RTEC)

    SciTech Connect

    Gordon, J.A.; Spector, A.A.

    1986-03-01

    To determine if 12-HETE, a lipoxygenase product that mediates inflammation and tissue injury, can interact with RTEC, confluent Madin Darby Canine Kidney (MDCK) cells were incubated for 2-16 hr with 1.0 ..mu..M (/sup 3/H)-12-HETE. Initial uptake of 12-HETE was rapid; at 16 hrs. 70% of the 12-HETE uptake was incorporated into phospholipids (PL). The distribution among the choline, ethanolamine, inositol, and serine PL was 36, 36, 20 and 8%, respectively. Incubation of MDCK cells with 0.5 to 5.0 ..mu..M (/sup 3/H)-12-HETE for 1 hr indicated linear uptake without evidence of saturation. Incubation with 1.0 ..mu..M 12-HETE and 0.25-10.0 ..mu..M arachidonic acid for 1 hr revealed no competition for uptake at the lower concentrations but a 40% reduction in 12-HETE uptake at 10.0 ..mu..M. Polarity of 12-HETE uptake was indicated by a preference of the basolateral surface over the apical surface by 1.4. After 2 hr, analysis of the medium by reverse phase HPLC revealed that 12-HETE was converted to three polar metabolites which eluted at 25.9, 29.4 and 31.3 min respectively; 12-HETE eluted at 37.5 min. The appearance of these polar metabolites was not prevented by ibuprofen (50 ..mu..M) nordihydroguaiaretic acid (30 ..mu..M), allopurinol (15 mM), or butylated hydroxytoluene (20 ..mu..M). These findings suggest that the lipoxygenase product 12-HETE may affect RTEC through incorporation into membrane PL and/or conversion to polar metabolites.

  11. Uptake and incorporation of saturated and unsaturated fatty acids into macrophage lipids and their effect upon macrophage adhesion and phagocytosis.

    PubMed Central

    Calder, P C; Bond, J A; Harvey, D J; Gordon, S; Newsholme, E A

    1990-01-01

    Murine thioglycollate-elicited peritoneal macrophages were cultured in the presence of a variety of fatty acids added as complexes with bovine serum albumin. All fatty acids tested were taken up readily by the cells and both neutral and phospholipid fractions were enriched with the fatty acid provided in the medium. This generated a range of cells enriched in saturated, monounsaturated or polyunsaturated fatty acids, including n-3 acids of fish oil origin. Saturated fatty acid enrichment enhanced macrophage adhesion to both tissue culture plastic and bacterial plastic compared with enrichment with polyunsaturated fatty acids. Macrophages enriched with the saturated fatty acids myristate or palmitate showed decreases of 28% and 21% respectively in their ability to phagocytose unopsonized zymosan particles. Those enriched with polyunsaturated fatty acids showed 25-55% enhancement of phagocytic capacity. The greatest rate of uptake was with arachidonate-enriched cells. Phagocytic rate was highly correlated with the saturated/unsaturated fatty acid ratio, percentage of polyunsaturated fatty acid and index of unsaturation, except for macrophages enriched with fish-oil-derived fatty acids; they showed lower phagocytic activity than expected on the basis of their degree of unsaturation. These results suggest that membrane fluidity is important in determining macrophage adhesion and phagocytic activity. However, in the case of phagocytosis, this effect may be partially overcome if the cells are enriched with fish-oil-derived fatty acids. Thus it may be possible to modulate the activity of cells of the immune system, and so an immune response, by dietary lipid manipulation. PMID:2117922

  12. Uptake of formaldehyde by sulfuric acid solutions - Impact on stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Tolbert, Margaret A.; Pfaff, Jeanne; Jayaweera, Indira; Prather, Michael J.

    1993-01-01

    The study investigates the uptake of CH2O by low temperature sulfuric acid solutions representative of global stratospheric particulate. It is argued that if similar uptake occurs under stratospheric pressures of CH2O, i.e., 1000 times lower than used in the present study, then the removal of CH2O from the gas phase can take away a significant source of odd hydrogen in the mid- and high-latitude lower stratosphere. It is shown that with the inclusion of this reaction, concentrations of OH and H2O are reduced by as much as 4 percent under background levels of aerosols and more than 15 percent under elevated (volcanic) conditions. The accumulation of CH2O in stratospheric aerosols over a season, reaching about 1 M solutions, will alter the composition and may even change the reactivity of these sulfuric acid-water mixtures.

  13. Uptake of methacrolein into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Wu, Ling-Yan; Wang, Tian-He; Ge, Mao-Fa; Wang, Wei-Gang

    2012-01-12

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol (SOA) formation from isoprene and its gas-phase oxidation products, but the kinetics and chemical mechanism remain largely uncertain. Here we report the first measurement of uptake of methacrolein into aqueous solutions of sulfuric acid and hydrogen peroxide in the temperature range of 253-293 K. The steady-state uptake coefficients were acquired and increased quickly with increasing sulfuric acid concentration and decreasing temperature. Propyne, acetone, and 2,3-dihydroxymethacrylic acid were suggested as the products. The chemical mechanism is proposed to be the oxidation of carbonyl group and C═C double bonds by peroxide hydrogen in acidic environment, which could explain the large content of polyhydroxyl compounds in atmospheric fine particles. These results indicate that multiphase acid-catalyzed oxidation of methacrolein by hydrogen peroxide can contribute to SOA mass in the atmosphere, especially in the upper troposphere.

  14. Optimising root system hydraulic architectures for water uptake

    NASA Astrophysics Data System (ADS)

    Meunier, Félicien; Couvreur, Valentin; Draye, Xavier; Javaux, Mathieu

    2015-04-01

    In this study we started from local hydraulic analysis of idealized root systems to develop a mathematical framework necessary for the understanding of global root systems behaviors. The underlying assumption of this study was that the plant is naturally optimised for the water uptake. The root system is thus a pipe network dedicated to the capture and transport of water. The main objective of the present research is to explain the fitness of major types of root architectures to their environment. In a first step, we developed links between local hydraulic properties and macroscopic parameters of (un)branched roots. The outcome of such an approach were functions of apparent conductance of entire root system and uptake distribution along the roots. We compared our development with some allometric scaling laws for the root water uptake: under the same simplifying assumptions we were able to obtain the same results and even to expand them to more physiological cases. Using empirical data of measured root conductance, we were also able to fit extremely well the data-set with this model. In a second stage we used generic architecture parameters and an existent root growth model to generate various types of root systems (from fibrous to tap). We combined both sides (hydraulic and architecture) then to maximize under a volume constraint either apparent conductance of root systems or the soil volume explored by active roots during the plant growth period. This approach has led to the sensitive parameters of the macroscopic parameters (conductance and location of the water uptake) of each single plant selected for this study. Scientific questions such as: "What is the optimal sowing density of a given hydraulic architecture ?" or "Which plant traits can we change to better explore the soil domain ?" can be also addressed with this approach: some potential applications are illustrated. The next (and ultimate phase) will be to validate our conclusions with real architectures

  15. Loss of activity of transforming deoxyribonucleic acid after uptake by Haemophilus influenzae.

    PubMed

    Voll, M J; Goodgal, S H

    1965-10-01

    Voll, Mary Jane (University of Pennsylvania, Philadelphia), and Sol H. Goodgal. Loss of activity of transforming deoxyribonucleic acid after uptake by Haemophilus influenzae. J. Bacteriol. 90:873-883. 1965.-Transforming deoxyribonucleic acid (DNA) which has been irreversibly removed from solution by competent cells undergoes a progressive loss in marker activity when tested by lysis of the cells and exposure to new recipient cells. The loss of activity is limited and marker-specific, with greater inactivation of those markers with lower efficiencies of transformation. Recipient factors or donor factors which have undergone recombination, as measured by the appearance of linked markers, do not undergo inactivation. The efficiency of transformation can be correlated with the sensitivity of a marker to inactivation after DNA uptake. A mutation which affects the efficiency of transformation is found to increase sensitivity to postuptake inactivation. The rate of inactivation is temperature-dependent. At temperatures of 20 and 45 C, marker inactivation can occur without concomitant recombination. During the uptake process, DNA is retained in an acid-insoluble form, indicating that the fate of Haemophilus influenzae DNA differs from the fate of transforming DNA in pneumococcus.

  16. Mammalian target of rapamycin signalling modulates amino acid uptake by regulating transporter cell surface abundance in primary human trophoblast cells.

    PubMed

    Rosario, Fredrick J; Kanai, Yoshikatsu; Powell, Theresa L; Jansson, Thomas

    2013-02-01

    Abnormal fetal growth increases the risk for perinatal complications and predisposes for the development of obesity, diabetes and cardiovascular disease later in life. Emerging evidence suggests that changes in placental amino acid transport directly contribute to altered fetal growth. However, the molecular mechanisms regulating placental amino acid transport are largely unknown. Here we combined small interfering (si) RNA-mediated silencing approaches with protein expression/localization and functional studies in cultured primary human trophoblast cells to test the hypothesis that mammalian target of rapamycin complex 1 (mTORC1) and 2 (mTORC2) regulate amino acid transporters by post-translational mechanisms. Silencing raptor (inhibits mTORC1) or rictor (inhibits mTORC2) markedly decreased basal System A and System L amino acid transport activity but had no effect on growth factor-stimulated amino acid uptake. Simultaneous inhibition of mTORC1 and 2 completely inhibited both basal and growth factor-stimulated amino acid transport activity. In contrast, mTOR inhibition had no effect on serotonin transport. mTORC1 or mTORC2 silencing markedly decreased the plasma membrane expression of specific System A (SNAT2, SLC38A2) and System L (LAT1, SLC7A5) transporter isoforms without affecting global protein expression. In conclusion, mTORC1 and mTORC2 regulate human trophoblast amino acid transporters by modulating the cell surface abundance of specific transporter isoforms. This is the first report showing regulation of amino acid transport by mTORC2. Because placental mTOR activity and amino acid transport are decreased in human intrauterine growth restriction our data are consistent with the possibility that dysregulation of placental mTOR plays an important role in the development of abnormal fetal growth.

  17. Synthesis of diethylenetriaminepentaacetic acid conjugated inulin and utility for cellular uptake of liposomes

    SciTech Connect

    Essien, H.; Lai, J.Y.; Hwang, K.J.

    1988-05-01

    The synthesis, binding of radioactive cations, liposomal encapsulation, and biodistribution of the oxidized-inulin reaction product with ethylenediamine and diethylenetriaminepentaacetic acid (4) are described. The four-step synthesis of the inulin derivative proceeded in a good overall yield of 72%. The complex of the inulin derivative with either /sup 67/Ga3+ or /sup 111/In3+ was stable in vivo and did not readily distribute into tissues, being excreted primarily in urine after intravenous administration to mice. The liposome-entrapped inulin derivative can be loaded with radioactive heavy metal cations by mobile ionophores in high radiochemical yields of 80-91%. Following the intravenous administration of the liposomal encapsulation of the indium-111-labeled inulin derivative, the entrapped compound had a biodistribution characteristic of liposomes and allowed an estimation of the extent of the intracellular uptake of liposomes. The ability of the inulin derivative to chelate many different types of metals will allow the use of this probe for studying subtle differences in tissue distribution resulting from different drug targeting or delivery protocols in the same animal by multiple labeling techniques. Moreover, the chelate-conjugated inulin permits studies of the applications of drug delivery systems in primates or human subjects by noninvasive techniques such as gamma-scintigraphic or nuclear magnetic resonance imaging methods.

  18. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa).

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; de Voogt, Pim

    2012-11-01

    An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant.

  19. Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

    SciTech Connect

    Junker, L.H.; Davis, R.A. )

    1989-12-01

    The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of (14C)cholesterol from (2-14C)acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of (14C)cholesterol from (2-14C)acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis.

  20. Ruminant and industrial trans-fatty acid uptake in the heart.

    PubMed

    Ganguly, Riya; LaVallee, Renee; Maddaford, Thane G; Devaney, Brittany; Bassett, Chantal M C; Edel, Andrea L; Pierce, Grant N

    2016-05-01

    Dietary trans-fats are strongly associated with heart disease. However, the capacity for the tissues of the body, and specifically the heart, to take up trans-fats is unknown. It is also unknown if different trans-fats have different uptake capacities in the heart and other tissues of the body. Diets of low-density lipoprotein receptor-deficient mice were supplemented for 14weeks with foods that contained 1.5% of the trans-fat elaidic acid or vaccenic acid. Tissues were extracted and frozen in liquid nitrogen, and then lipids were analyzed by gas chromatography for fatty acid content. Isolated cardiomyocytes were also exposed to elaidic or vaccenic acid in cell culture media for 24h. Dietary supplementation with vaccenic or elaidic acid resulted in a 20-fold higher accumulation of these TFAs in fat deposits in the body in comparison to liver. Liver tissue accumulated about twice as much per gram tissue as heart. Similar quantities of both elaidic acid and vaccenic acid were taken up by the tissues. Isolated cardiomyocytes exhibited an unusually large uptake of trans-fat, and this was dependent upon both the concentration and duration of exposure to the trans-fats but not upon the type of trans-fat. Expression levels of CD36 and FATP4 were not significantly changed during dietary interventions or exposure of cells to trans-fats. We conclude that fat, liver and heart (including cardiomyocytes) are all capable of accumulating trans-fat in response to dietary supplementation without changes in fatty acid transport protein expression.

  1. Ruminant and industrial trans-fatty acid uptake in the heart.

    PubMed

    Ganguly, Riya; LaVallee, Renee; Maddaford, Thane G; Devaney, Brittany; Bassett, Chantal M C; Edel, Andrea L; Pierce, Grant N

    2016-05-01

    Dietary trans-fats are strongly associated with heart disease. However, the capacity for the tissues of the body, and specifically the heart, to take up trans-fats is unknown. It is also unknown if different trans-fats have different uptake capacities in the heart and other tissues of the body. Diets of low-density lipoprotein receptor-deficient mice were supplemented for 14weeks with foods that contained 1.5% of the trans-fat elaidic acid or vaccenic acid. Tissues were extracted and frozen in liquid nitrogen, and then lipids were analyzed by gas chromatography for fatty acid content. Isolated cardiomyocytes were also exposed to elaidic or vaccenic acid in cell culture media for 24h. Dietary supplementation with vaccenic or elaidic acid resulted in a 20-fold higher accumulation of these TFAs in fat deposits in the body in comparison to liver. Liver tissue accumulated about twice as much per gram tissue as heart. Similar quantities of both elaidic acid and vaccenic acid were taken up by the tissues. Isolated cardiomyocytes exhibited an unusually large uptake of trans-fat, and this was dependent upon both the concentration and duration of exposure to the trans-fats but not upon the type of trans-fat. Expression levels of CD36 and FATP4 were not significantly changed during dietary interventions or exposure of cells to trans-fats. We conclude that fat, liver and heart (including cardiomyocytes) are all capable of accumulating trans-fat in response to dietary supplementation without changes in fatty acid transport protein expression. PMID:27133424

  2. Dietary uptake of omega-3 fatty acids in mouse tissue studied by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

    PubMed

    Sjövall, Peter; Rossmeisl, Martin; Hanrieder, Jörg; Kuda, Ondrej; Kopecky, Jan; Bryhn, Morten

    2015-07-01

    Dietary intake of omega-3 fatty acids is associated with considerable health benefits, including the prevention of metabolic disorders such as cardiovascular disease and type 2 diabetes. Furthermore, incorporation of the main omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), at the systemic level has been found to be more efficient when these fatty acids are supplied in the form of marine phospholipids compared to triglycerides. In this work, the uptake of omega-3 fatty acids and their incorporation in specific lipids were studied in adipose, skeletal muscle, and liver tissues of mice given high-fat diets with or without omega-3 supplements in the form of phospholipids or triglycerides using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results demonstrate significant uptake of EPA and DHA, and the incorporation of these fatty acids in specific lipid molecules, in all three tissue types in response to the dietary omega-3 supplements. Moreover, the results indicate reduced concentrations of arachidonic acid (AA) and depletion of lipids containing AA in tissue samples from mice given supplementary omega-3, as compared to the control mice. The effect on the lipid composition, in particular the DHA uptake and AA depletion, was found to be significantly stronger when the omega-3 supplement was supplied in the form of phospholipids, as compared to triglycerides. TOF-SIMS was found to be a useful technique for screening the lipid composition and simultaneously obtaining the spatial distributions of various lipid classes on tissue surfaces.

  3. Dietary uptake of omega-3 fatty acids in mouse tissue studied by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

    PubMed

    Sjövall, Peter; Rossmeisl, Martin; Hanrieder, Jörg; Kuda, Ondrej; Kopecky, Jan; Bryhn, Morten

    2015-07-01

    Dietary intake of omega-3 fatty acids is associated with considerable health benefits, including the prevention of metabolic disorders such as cardiovascular disease and type 2 diabetes. Furthermore, incorporation of the main omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), at the systemic level has been found to be more efficient when these fatty acids are supplied in the form of marine phospholipids compared to triglycerides. In this work, the uptake of omega-3 fatty acids and their incorporation in specific lipids were studied in adipose, skeletal muscle, and liver tissues of mice given high-fat diets with or without omega-3 supplements in the form of phospholipids or triglycerides using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results demonstrate significant uptake of EPA and DHA, and the incorporation of these fatty acids in specific lipid molecules, in all three tissue types in response to the dietary omega-3 supplements. Moreover, the results indicate reduced concentrations of arachidonic acid (AA) and depletion of lipids containing AA in tissue samples from mice given supplementary omega-3, as compared to the control mice. The effect on the lipid composition, in particular the DHA uptake and AA depletion, was found to be significantly stronger when the omega-3 supplement was supplied in the form of phospholipids, as compared to triglycerides. TOF-SIMS was found to be a useful technique for screening the lipid composition and simultaneously obtaining the spatial distributions of various lipid classes on tissue surfaces. PMID:25694146

  4. Purification of organic acids by chromatography with strong anionic resins: Investigation of uptake mechanisms.

    PubMed

    Lemaire, Julien; Blanc, Claire-Line; Lutin, Florence; Théoleyre, Marc-André; Stambouli, Moncef; Pareau, Dominique

    2016-08-01

    Bio-based organic acids are promising renewable carbon sources for the chemical industry. However energy-consuming purification processes are used, like distillation or crystallization, to reach high purities required in some applications. That is why preparative chromatography was studied as an alternative separation technique. In a previous work dealing with the purification of lactic, succinic and citric acids, the Langmuir model was insufficient to explain the elution profiles obtained with a strong anionic resin. Consequently the Langmuir model was coupled with a usual ion-exchange model to take into account the retention of their conjugate bases (<2%), which are commonly neglected at low pH (<1.5). Elution simulations with both uptake mechanisms fitted very well with experimental pulse tests. Only two parameters were optimized (equilibrium constant of acid uptake and ion-exchange selectivity coefficient of conjugate base) and their value were coherent with experimental and resin suppliers' data. These results confirmed that the singular tailing and apparent delay observed with succinic and citric acids can be explained by the high affinity of succinate and citrate for resin cationic sites. The model was implemented in a preparative chromatography simulation program in order to optimize operating parameters of our pilot-scale ISMB unit (Improved Simulated Moving Bed). The comparison with experimental ISMB profiles was conclusive. PMID:27373374

  5. Purification of organic acids by chromatography with strong anionic resins: Investigation of uptake mechanisms.

    PubMed

    Lemaire, Julien; Blanc, Claire-Line; Lutin, Florence; Théoleyre, Marc-André; Stambouli, Moncef; Pareau, Dominique

    2016-08-01

    Bio-based organic acids are promising renewable carbon sources for the chemical industry. However energy-consuming purification processes are used, like distillation or crystallization, to reach high purities required in some applications. That is why preparative chromatography was studied as an alternative separation technique. In a previous work dealing with the purification of lactic, succinic and citric acids, the Langmuir model was insufficient to explain the elution profiles obtained with a strong anionic resin. Consequently the Langmuir model was coupled with a usual ion-exchange model to take into account the retention of their conjugate bases (<2%), which are commonly neglected at low pH (<1.5). Elution simulations with both uptake mechanisms fitted very well with experimental pulse tests. Only two parameters were optimized (equilibrium constant of acid uptake and ion-exchange selectivity coefficient of conjugate base) and their value were coherent with experimental and resin suppliers' data. These results confirmed that the singular tailing and apparent delay observed with succinic and citric acids can be explained by the high affinity of succinate and citrate for resin cationic sites. The model was implemented in a preparative chromatography simulation program in order to optimize operating parameters of our pilot-scale ISMB unit (Improved Simulated Moving Bed). The comparison with experimental ISMB profiles was conclusive.

  6. The Campylobacter jejuni Ferric Uptake Regulator Promotes Acid Survival and Cross-Protection against Oxidative Stress

    PubMed Central

    Askoura, Momen; Sarvan, Sabina; Couture, Jean-François

    2016-01-01

    Campylobacter jejuni is a prevalent cause of bacterial gastroenteritis in humans worldwide. The mechanisms by which C. jejuni survives stomach acidity remain undefined. In the present study, we demonstrated that the C. jejuni ferric uptake regulator (Fur) plays an important role in C. jejuni acid survival and acid-induced cross-protection against oxidative stress. A C. jejuni Δfur mutant was more sensitive to acid than the wild-type strain. Profiling of the acid stimulon of the C. jejuni Δfur mutant allowed us to uncover Fur-regulated genes under acidic conditions. In particular, Fur was found to upregulate genes involved in flagellar and cell envelope biogenesis upon acid stress, and mutants with deletions of these genes were found to be defective in surviving acid stress. Interestingly, prior acid exposure of C. jejuni cross-protected against oxidative stress in a catalase (KatA)- and Fur-dependent manner. Western blotting and reverse transcription-quantitative PCR revealed increased expression of KatA upon acid stress. Electrophoretic mobility shift assays (EMSAs) demonstrated that the binding affinity between Fur and the katA promoter is reduced in vitro under conditions of low pH, rationalizing the higher levels of expression of katA under acidic conditions. Strikingly, the Δfur mutant exhibited reduced virulence in both human epithelial cells and the Galleria mellonella infection model. Altogether, this is the first study showing that, in addition to its role in iron metabolism, Fur is an important regulator of C. jejuni acid responses and this function cross-protects against oxidative stress. Moreover, our results clearly demonstrate Fur's important role in C. jejuni pathogenesis. PMID:26883589

  7. Assessment of plant-driven uptake and translocation of clofibric acid by Scirpus validus.

    PubMed

    Zhang, Dong Qing; Gersberg, Richard M; Hua, Tao; Zhu, Junfei; Ng, Wun Jern; Tan, Soon Keat

    2013-07-01

    Pharmaceutical compounds are now considered as emerging contaminants of environmental concern. The overall objective of this study was to evaluate the uptake and translocation of clofibric acid (CA) by the macrophyte Scirpus validus growing hydroponically. A set of the three replicates was established for each exposure time and for each CA concentration. Plants were grown in 4 L vessels (four plants per vessel corresponding to the three exposure period studies, i.e., 7, 14, 18, and 21 days) which contained an aerated modified Hoagland nutrient solution that was spiked with CA at concentrations of 0.5, 1.0, and 2.0 mg L(-1). At each exposure period, CA concentration was measured in the nutrient solutions. A sea sand disruption method was employed for the extraction of CA from plant tissues. The determination of the pharmaceutical concentration was carried out using solid phase extraction (SPE) followed by chromatographic analysis. The quantification of CA concentrations in both nutrient solutions (after SPE) and plant tissues (after extraction) was conducted by chromatographic analysis. CA concentrations of 5.4-26.8 μg g(-1) (fresh weight) were detected in the roots and 7.2-34.6 μg g(-1) (fresh weight) in the shoots after 21 days. Mass balance calculations showed that S. validus uptake alone accounted for a significant contribution (6-13% for the roots and 22-49% for the shoots) of the total loss of CA. The bioaccumulation factors (BAFs) based on fresh weight for the roots ranged from 6.6 to 23.2, while values for the shoots ranged from 9.5 to 32.1. All the BAFs for the shoots were greater than those in the roots, implying that CA has greater tendency to be translocated to the shoots, rather than the roots of S. validus. All the shoot-to-root concentration ratios were more than 1, denoting that the shoots of S. validus do preferentially accumulate CA. We demonstrated that CA can be actively taken up, subsequently translocated and accumulated by aboveground

  8. Effects of gamma-aminobutyric acid on skate retinal horizontal cells: evidence for an electrogenic uptake mechanism.

    PubMed Central

    Malchow, R P; Ripps, H

    1990-01-01

    In the retinae of many vertebrates, there are classes of horizontal cell that probably utilize gamma-aminobutyric acid (GABA) as a neurotransmitter. As with other amino acid transmitter agents, the postsynaptic action of GABA is thought to be terminated by uptake into neurons and glia surrounding the release site. The present study examined whether an uptake system for GABA could be detected in isolated skate horizontal cells by means of electrophysiological methods. Pressure ejection of GABA onto voltage-clamped horizontal cells produced an inward current that showed no sign of desensitization regardless of the GABA concentration. The dose-response relationship followed simple Michaelis-Menten kinetics, with a half-maximal response elicited at approximately 110 microM. Nipecotic acid produced a similar current and reduced the responses to GABA when introduced in the bath solution prior to the GABA pulse. On the other hand, application of 500 microM muscimol or 1 mM baclofen, GABAA and GABAB receptor agonists, respectively, were completely without effect. The GABA-induced current was not blocked by superfusion with 500 microM bicuculline, 500 microM picrotoxin, or 500 microM phaclofen. However, the responses to GABA were abolished when the cells were superfused in Ringer's solution in which choline or lithium had been substituted for sodium, and were reduced when the extracellular chloride concentration was decreased from 266 mM to 16 mM. Current-voltage data showed a maximal response to GABA when the cells were held at or below their resting potential. At more depolarized levels, the inward current became progressively smaller until, near +50 mV, it could no longer be detected; over the range tested (-90 to +50 mV), the response never reversed into an outward current. These findings suggest that the GABA-induced currents in skate horizontal cells are mediated by an electrogenic uptake mechanism. PMID:2247470

  9. Uptake of inorganic and amino acid nitrogen from soil by Eucalyptus regnans and Eucalyptus pauciflora seedlings.

    PubMed

    Warren, Charles R

    2009-03-01

    This study examined whether two species of Eucalyptus can take up the amino acid glycine from soil and compared the uptake rate of glycine with the uptake rates of nitrate and ammonium. Ectomycorrhizal seedlings of two ecologically disparate species were studied: Eucalyptus regnans F. Muell., a fast-growing forest tree from low altitudes; and Eucalyptus pauciflora Sieber ex Spreng., a slow-growing tree that forms the alpine treeline. Seedlings were grown from seeds in field soil. When seedlings were 4-5 months old, soils were injected with equimolar mixtures of isotope-labeled glycine, ammonium and nitrate. Seedlings and soil were harvested 4 and 48 h later. Isotope ratio mass spectrometry analysis of (13)C and (15)N enrichment in plants receiving glycine indicated uptake of 1.5 (13)C for every (15)N at the 4-h harvest (versus 2:1 (13)C:(15)N in labeled glycine), suggesting intact uptake of around 75% of glycine. Gas chromatography-mass spectrometry analysis detected intact (13)C(2),(15)N-glycine in roots, but the pool of (13)C(2),(15)N-glycine was 10-500 times smaller than (13)C and (15)N excess, and no (13)C(2),(15)N-glycine was detected in shoots. This is consistent with glycine being taken up as an intact molecule that is subsequently metabolized rapidly. Both species took up more nitrate than ammonium, and glycine was the least preferred form of nitrogen (N). Microbes took up more N than seedlings, and their preference for N forms was the mirror image of the plant preferences. These data suggest that patterns of microbial uptake may determine plant preference for forms of N. PMID:19203963

  10. The uptake and distribution of cadmium in tomato plants as affected by ethylenediaminetetraacetic acid and 2,4-dinitrophenol.

    PubMed

    Wolterbeek, H T; van der Meer, A; de Bruin, M

    1988-01-01

    The uptake and distribution of cadmium in tomato plants (Lycopersicon esculentum, Mill, cv. Tiny Tim) were examined with and without the presence of ethylenediaminetetraacetic acid (EDTA) as chelating agent and 2,4-dinitrophenol (DNP) as metabolic inhibitor. Eight-week-old intact and derooted tomato seedlings were used in hydroculture experiments with cadmium applied as (115)Cd(NO(3))(2) in a range of concentrations. Measurements of the (115)Cd content of roots, stems and leaves were carried out by gamma-ray spectroscopy. The data showed that applications of both EDTA and DNP resulted in reduced total Cd accumulation in the plants, but relatively enhanced Cd transport into the above-ground plant parts. The Cd mobility in the transport channels in the shoots was increased by EDTA in both intact and derooted plants. Application of DNP leads to increased relative Cd import to leaves in derooted plants, but a reduced import into leaves of intact plants. These results suggest that Cd-complexes are formed in root cells before root-to-shoot transport. Furthermore, initial Cd uptake may be associated with adsorption on the negative charges of the cell walls of the root system. The high Cd mobility in shoots, in experiments with intact plants and Cd-EDTA application, indicates the possibility of simultaneous uptake of Cd and EDTA, possibly as a Cd-EDTA complex. PMID:15092498

  11. Drug uptake systems in liver and kidney: historic perspective

    PubMed Central

    Hagenbuch, Bruno

    2010-01-01

    Drugs and their metabolites are mainly eliminated by excretion into urine and bile. Studies in whole animals, isolated organs, cells and membrane vesicles led to the conclusion that different transport systems are responsible for the transport of different classes of organic compounds (small large, anionic, cationic). In the early 1990's functional expression cloning resulted in the identification of the first transporters for organic anions and cations. Eventually, all the major transport systems involved in the uptake of these organic compounds have been cloned and characterized and we know that they belong to the OATs and OCTs of the SLC22A and the OATPs of the SLCO superfamilies of polyspecific drug transporters. Today we can explain at the molecular level why small and hydrophilic organic compounds are predominantly excreted via urine while large and amphipathic compounds are mainly excreted via bile and we can start to predict drug-drug interactions for new compounds. PMID:19924123

  12. Effect of HEPES buffer on the uptake and transport of P-glycoprotein substrates and large neutral amino acids

    PubMed Central

    Luo, Shuanghui; Pal, Dhananjay; Shah, Sujay J.; Kwatra, Deep; Paturi, Kalyani D.; Mitra, Ashim. K.

    2010-01-01

    HEPES has been widely employed as an organic buffer agent in cell culture medium as well as uptake and transport experiments in vitro. However, concentrations of HEPES used in such studies vary from one laboratory to another. In this study, we investigated the effect of HEPES on the uptake and bidirectional transport of P-gp substrates employing both Caco-2 and MDCK-MDR1 cells. ATP-dependent uptake of glutamic acid was also examined. ATP production was further quantified applying ATP Determination Kit. An addition of HEPES to the cellular washing and incubation media significantly altered the uptake and transport of P-gp substrates in both Caco-2 and MDCK-MDR1 cells. Uptake of P-gp substrates substantially diminished as the HEPES concentration was raised to 25 mM. Bidirectional (A-B and B-A) transport studies revealed that permeability ratio of PappB-A to PappA-B in the presence of 25 mM HEPES was significantly higher than control. The uptake of phenylalanine is an ATP-independent process, whereas the accumulation of glutamic acid is ATP-dependent. While phenylalanine uptake remained unchanged glutamic acid uptake was elevated with the addition of HEPES. Verapamil is an inhibitor of P-gp mediated uptake, elevation of cyclosporine uptake in the presence of 5 μM verapamil was compromised by the presence of 25 mM HEPES. The results of ATP assay indicated that HEPES stimulated the production of ATP. This study suggests that the addition of HEPES in the medium modulated the energy dependent efflux and uptake processes. The effect of HEPES on P-gp mediated drug efflux and transport may provide some mechanistic insight into possible reasons for inconsistencies in the results reported from various laboratories. PMID:20163160

  13. Uranyl ion uptake capacity of poly (N-isopropylacrylamide/maleic acid) copolymeric hydrogels prepared by gamma rays

    NASA Astrophysics Data System (ADS)

    Kam, Erol; Taşdelen, Betul; Osmanlioglu, A. Erdal

    2012-06-01

    The effect of gel composition, absorbed dose and pH of the solution on the uranyl ion uptake capacity of N-isopropylacrylamide/maleic acid copolymeric hydrogels containing 0-3 mol% of maleic acid at 48 kGy have been investigated. Uranyl uptake capacity of hydrogels are found to increase from 18.5 to 94.8 mg [UO22+]/g dry gel as the mole % of maleic acid content in the gel structure increased from 0 to 3. The percent swelling, equilibrium swelling and diffusion coefficient values have been evaluated for poly(N-isopropylacrylamide/maleic acid) hydrogels at 500 ppm of uranyl nitrate solution.

  14. [Cd uptake in rice cultivars and Cd fractions in soil treated with organic acids and EDTA].

    PubMed

    Zhang, Hai-Bo; Li, Yang-Rui; Xu, Wei-Hong; Chen, Gui-Qing; Wang, Hui-Xian; Han, Gui-Qi; Zhang, Xiao-Jing; Xiong, Zhi-Ting; Zhang, Jin-Zhong; Xie, De-Ti

    2011-09-01

    A pot experiment was conducted to examine the yield, quality and cadmium (Cd) uptake in different rice cultivars, and Cd speciation in soil after exposing to Cd (0, 1 and 5 mg x kg(-1)) in the presence of organic acids and ethylenediamine tetraacetic acid (EDTA). The results showed that general increase in the yield for cultivars Xiushui63 and II you527 was observed. Yield of two rice cultivars were in order of organic acids treatment or organic acids + 1/2EDTA treatment > EDTA treatment. The exchangeable, carbonate related and ferric-manganese oxidation related Cd increased; while organic complexation Cd and residules decreased in the presence of organic acids and EDTA. Cadmium concentrations in grain, straw and roots of both cultivars markedly reduced in the presence of organic acids and EDTA. Grain Cd concentration was the lowest for plants treated with EDTA, followed by organic acids + 1/2EDTA, and the highest Cd concentration in grain was found in the treatment with organic acids. Grain Cd concentration decreased by 9.0% to 49.3% and 16.5% to 30.6% at 1 mg x kg(-1) Cd in the presence of organic acids and EDTA, and by 12.7% to 28.5% and 4.3% to 19.1% at 5 mg x kg(-1) Cd. Cadmium concentration and accumulation in plants and total Cd content in soil were higher in Xiushui63 than in that in II you527. Grain Cd concentration decreased, and yield and quality of two rice cultivars increased at the same time in the presence of organic acids + 1/2EDTA.

  15. Uptake of intact zinc-ethylenediaminetetraacetic acid from soil is dependent on plant species and complex concentration.

    PubMed

    Collins, Richard N; Merrington, Graham; McLaughlin, Mike J; Knudsen, Chris

    2002-09-01

    Pot experiments were conducted with barley (Hordeum vulgare L.), potato (Solanum tuberosum L.), Indian mustard (Brassicajuncea L.), and white lupin (Lupinus albus L.) to determine the nature of Zn mobilization, uptake, and root-shoot transport from a Zn-contaminated soil in the presence of increasing concentrations of ethylenediaminetetraacetic acid (EDTA; 0.0-3.4 mmole/kg soil). Increasing EDTA concentrations lead to a greater proportion of soil-solution Zn being detected as the ZnEDTA complex. However, a significant increase in the concentration of soil-solution Zn was only observed after the addition of 3.4 mmole EDTA/ kg soil. At this application rate, regardless of the plant species, 97 +/- 9% (+/- SD) of the increase in soil-solution Zn could be accounted for by chelation/desorption, and 89 +/- 9% of total Zn in solution was measured as ZnEDTA. Although the complex was detected in the xylem exudate of B. juncea after 0.34 mmole EDTA/kg soil had been added, ZnEDTA was only found in the xylem exudate of the other plant species following the highest application rate of EDTA. In this case, the accumulation of Zn and the concentration of ZnEDTA in the xylem sap of B. juncea were significantly greater than those of H. vulgare and S. tuberosum. Measurements of plant transpiration following the addition of EDTA indicated that B. juncea experienced greater physiological stress in the presence of high concentrations of EDTA. It was therefore concluded that two different mechanisms of ZnEDTA uptake existed for these plant species. Based on a review of the literature, it was hypothesized that uptake of ZnEDTA by B. juncea occurred only after physiological damage to its root system, whereas uptake by H. vulgare and S. tuberosum was via an apoplastic pathway (passive extracellular transport into the xylem).

  16. Pulmonary alveolar epithelial uptake of S-nitrosothiols is regulated by L-type amino acid transporter.

    PubMed

    Granillo, Olivia M; Brahmajothi, Mulugu V; Li, Sheng; Whorton, A Richard; Mason, S Nicholas; McMahon, Timothy J; Auten, Richard L

    2008-07-01

    Nitric oxide (NO) effects are often mediated via S-nitrosothiol (SNO) formation; SNO uptake has recently been shown to be mediated in some cell types via system L-type amino acid transporters (LAT-1, 2). Inhaled NO therapy may exert some biological effects via SNO formation. We therefore sought to determine if pulmonary epithelial SNO uptake depended on LAT or peptide transporter 2 (PEPT2). Both LAT-1 and PEPT2 proteins were detected by immunoblot and immunocytochemistry in L2 cells and rat lung. We tested SNO uptake through the transporters by exposing rat alveolar epithelial cells (L2 and type II) to RSNOs: S-nitrosoglutathione, S-nitrosocysteinylglycine (SNO-Cys-Gly), S-nitrosocysteine (CSNO), and to NO donor diethylamine NONOate (DEA-NONOate). SNO was detected in cell lysates by ozone chemiluminescence. NO uptake was detected by fluorescence in alveolar epithelial cells loaded with 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM) diacetate cultured in submersion and exposed to RSNOs and DEA NONOate. Addition of L-Cys but not D-Cys to RSNOs or DEA NONOate increased SNO and DAF-FM signal that was inhibited by coincubation with LAT competitors. Incubation of cells with PEPT2 substrate SNO-Cys-Gly showed no increase in SNO or DAF-FM signal unless incubated with L-Cys. This was unaffected by PEPT2 inhibition. We conclude that RSNOs (thionitrites, S-nitrosothiols) and NO enter alveolar epithelial cells predominantly by S-nitrosation of L-Cys, which is then imported through LAT.

  17. Proton-dependent glutamine uptake by aphid bacteriocyte amino acid transporter ApGLNT1.

    PubMed

    Price, Daniel R G; Wilson, Alex C C; Luetje, Charles W

    2015-10-01

    Aphids house large populations of the gammaproteobacterial symbiont Buchnera aphidicola in specialized bacteriocyte cells. The combined biosynthetic capability of the holobiont (Acyrthosiphon pisum and Buchnera) is sufficient for biosynthesis of all twenty protein coding amino acids, including amino acids that animals alone cannot synthesize; and that are present at low concentrations in A. pisum's plant phloem sap diet. Collaborative holobiont amino acid biosynthesis depends on glutamine import into bacteriocytes, which serves as a nitrogen-rich amino donor for biosynthesis of other amino acids. Recently, we characterized A. pisum glutamine transporter 1 (ApGLNT1), a member of the amino acid/auxin permease family, as the dominant bacteriocyte plasma membrane glutamine transporter. Here we show ApGLNT1 to be structurally and functionally related to mammalian proton-dependent amino acid transporters (PATs 1-4). Using functional expression in Xenopus laevis oocytes, combined with two-electrode voltage clamp electrophysiology we demonstrate that ApGLNT1 is electrogenic and that glutamine induces large inward currents. ApGLNT1 glutamine induced currents are dependent on external glutamine concentration, proton (H+) gradient across the membrane, and membrane potential. Based on these transport properties, ApGLNT1-mediated glutamine uptake into A. pisum bacteriocytes can be regulated by changes in either proton gradients across the plasma membrane or membrane potential. PMID:26028424

  18. PDR-type ABC transporter mediates cellular uptake of the phytohormone abscisic acid

    PubMed Central

    Kang, Joohyun; Hwang, Jae-Ung; Kim, Yu-Young; Assmann, Sarah M.; Martinoia, Enrico; Lee, Youngsook

    2010-01-01

    Abscisic acid (ABA) is a ubiquitous phytohormone involved in many developmental processes and stress responses of plants. ABA moves within the plant, and intracellular receptors for ABA have been recently identified; however, no ABA transporter has been described to date. Here, we report the identification of the ATP-binding cassette (ABC) transporter Arabidopsis thaliana Pleiotropic drug resistance transporter PDR12 (AtPDR12)/ABCG40 as a plasma membrane ABA uptake transporter. Uptake of ABA into yeast and BY2 cells expressing AtABCG40 was increased, whereas ABA uptake into protoplasts of atabcg40 plants was decreased compared with control cells. In response to exogenous ABA, the up-regulation of ABA responsive genes was strongly delayed in atabcg40 plants, indicating that ABCG40 is necessary for timely responses to ABA. Stomata of loss-of-function atabcg40 mutants closed more slowly in response to ABA, resulting in reduced drought tolerance. Our results integrate ABA-dependent signaling and transport processes and open another avenue for the engineering of drought-tolerant plants. PMID:20133880

  19. Effect of surface and membrane potentials on IAA (indoleactic acid) uptake and binding by zucchini membrane vesicles

    SciTech Connect

    Clark, K.A.; Goldsmith, M.H.M.

    1986-08-01

    The polar transport of the endogenous hormone controlling extension growth of plant cells, indoleacetic acid (IAA), is thought to depend on transmembrane pH and electrical gradients resulting in part from the action of proton ATPases in the plasma membrane. Elements of this transport process are permeation of the membrane by the undissociated lipophilic indoleacetic acid (IAAH) from the acidic apoplast, followed by dissociation of the weak acid and accumulation of the IAA anion (IAA/sup -/) in the alkaline cytoplasm; a saturable symport of IAA/sup -/ with one or more protons; a carrier-mediated efflux of IAA/sup -/ down a considerable electrochemical gradient. The efflux is greater from the basal than the apical end of cells and is thought to be responsible for the overall polarity of the process. This step is also the site of action of napthylphthalamic acid (NPA) and herbicides that inhibit polar transport but stimulate net accumulation of auxin by tissues and cells. We are using membrane vesicles as a simplified system for studying the mechanisms involved in the transport and accumulation of auxin. In particular, we are interested in determining the involvement of the transmembrane pH (pH/sub o/ < pH/sub i/) and voltage gradients (K/sup +/ diffusion potential, (K/sup +/)/sub in/ > (K/sup +/)/sub out/) in IAA uptake. 19 refs., 6 figs.

  20. Uptake of perfluorinated alkyl acids by hydroponically grown lettuce (Lactuca sativa).

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; de Voogt, Pim

    2012-11-01

    An uptake study was carried out to assess the potential human exposure to perfluorinated alkyl acids (PFAAs) through the ingestion of vegetables. Lettuce (Lactuca sativa) was grown in PFAA-spiked nutrient solutions at four different concentrations, ranging from 10 ng/L to 10 μg/L. Eleven perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were analyzed by HPLC-MS/MS. At the end of the experiment, the major part of the total mass of each of the PFAAs (except the short-chain, C4-C7, PFCAs) taken up by plants appeared to be retained in the nonedible part, viz. the roots. Root concentration factors (RCF), foliage/root concentration factors (FRCF), and transpiration stream concentration factors (TSCF) were calculated. For the long chained PFAAs, RCF values were highest, whereas FRCF were lowest. This indicates that uptake by roots is likely governed by sorption of PFAAs to lipid-rich root solids. Translocation from roots to shoots is restricted and highly depending on the hydrophobicity of the compounds. Although the TSCF show that longer-chain PFCAs (e.g., perfluorododecanoic acid) get better transferred from the nutrient solution to the foliage than shorter-chain PFCAs (e.g., perfluoroheptanoic acid), the major fraction of longer-chain PFCAs is found in roots due to additional adsorption from the spiked solution. Due to the strong electron-withdrawing effect of the fluorine atoms the role of the negative charge of the dissociated PFAAs is likely insignificant. PMID:23043263

  1. Influence of salinity and temperature on uptake of perfluorinated carboxylic acids (PFCAs) by hydroponically grown wheat (Triticum aestivum L.).

    PubMed

    Zhao, Hongxia; Qu, Baocheng; Guan, Yue; Jiang, Jingqiu; Chen, Xiuying

    2016-01-01

    Perfluoroalkyl substances (PFASs) have recently attracted increasing concerns due to their ubiquitous existence, adverse effects and persistence in environment. This study employed four perfluorinated carboxylic acids (PFCAs) to examine effects of salinity and temperature on the PFAS uptake in wheat, one of the major crops in the North China Plain. Wheat plants were grown in the spiked-PFCA hydroponic culture system at different salinities and temperatures. As expected, salinity and temperature significantly impacted the root uptake and translocation of wheat to four PFCAs, and the concentrations for each of PFCAs in wheat root and shoot increased with increasing salinity and temperature, respectively. PFCA concentrations at high salinity or high temperature were up to thrice those found at low salinity or low temperature. Except for perfluorobutanoic acid, the amount of PFCAs in root was always higher than that in shoot at the ranges of salinity and temperature tested. Additionally salinity and temperature were also capable of influencing the transfer factors (TFs) of four PFCAs, and significant increase was observed in the TFs in response to the increases in salinity and temperature.

  2. Influence of salinity and temperature on uptake of perfluorinated carboxylic acids (PFCAs) by hydroponically grown wheat (Triticum aestivum L.).

    PubMed

    Zhao, Hongxia; Qu, Baocheng; Guan, Yue; Jiang, Jingqiu; Chen, Xiuying

    2016-01-01

    Perfluoroalkyl substances (PFASs) have recently attracted increasing concerns due to their ubiquitous existence, adverse effects and persistence in environment. This study employed four perfluorinated carboxylic acids (PFCAs) to examine effects of salinity and temperature on the PFAS uptake in wheat, one of the major crops in the North China Plain. Wheat plants were grown in the spiked-PFCA hydroponic culture system at different salinities and temperatures. As expected, salinity and temperature significantly impacted the root uptake and translocation of wheat to four PFCAs, and the concentrations for each of PFCAs in wheat root and shoot increased with increasing salinity and temperature, respectively. PFCA concentrations at high salinity or high temperature were up to thrice those found at low salinity or low temperature. Except for perfluorobutanoic acid, the amount of PFCAs in root was always higher than that in shoot at the ranges of salinity and temperature tested. Additionally salinity and temperature were also capable of influencing the transfer factors (TFs) of four PFCAs, and significant increase was observed in the TFs in response to the increases in salinity and temperature. PMID:27186505

  3. Dihydrotestosterone stimulates amino acid uptake and the expression of LAT2 in mouse skeletal muscle fibres through an ERK1/2-dependent mechanism.

    PubMed

    Hamdi, M M; Mutungi, G

    2011-07-15

    Dihydrotestosterone (DHT) has acute/non-genomic actions in adult mammalian skeletal muscles whose physiological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the acute/non-genomic effects of DHT on amino acid uptake as well as the cellular signal transduction events underlying these actions in mouse fast- and slow-twitch skeletal muscle fibre bundles. 14C-Labelled amino acids were used to investigate the effects of DHT and testosterone (T) on amino acid uptake and pharmacological interventions were used to determine the cellular signal transduction events mediating these actions. While T had no effect on the uptake of isoleucine (Ile) and α-methylaminoisobutyric acid (MeAIB) in both fibre types, DHT increased their uptake in the fast-twitch fibre bundles. This effect was reversed by inhibitors of protein translation, the epidermal growth factor receptor (EGFR), system A, system L, mTOR and MEK. However, it was relatively insensitive to inhibitors of transcription, androgen receptors and PI3K/Akt. Additionally, DHT treatment increased the expression of LAT2 and the phosphorylation of the EGFR in the fast-twitch fibre bundles and that of ERK1/2, RSK1/2 and ATF2 in both fibre types. Also, it decreased the phosphorylation of eEF2 and increased the incorporation of Ile into proteins in both fibre types. Most of these effects were reversed by EGFR and MEK inhibitors. From these findings we suggest that another physiological function of the acute/non-genomic actions of DHT in isolated mammalian skeletal muscle fibres is to stimulate amino acid uptake. This effect is mediated through the EGFR and involves the activation of the MAPK pathway and an increase in LAT2 expression.

  4. Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

    NASA Technical Reports Server (NTRS)

    Vessey, J. K.; Henry, L. T.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

  5. Effects of fatty acids on benzo[a]pyrene uptake and metabolism in human lung adenocarcinoma A549 cells.

    PubMed

    Barhoumi, Rola; Mouneimne, Youssef; Chapkin, Robert S; Burghardt, Robert C

    2014-01-01

    Dietary supplementation with natural chemoprotective agents is receiving considerable attention because of health benefits and lack of toxicity. In recent in vivo and in vitro experimental studies, diets rich in n-3 polyunsaturated fatty acids have been shown to provide significant anti-tumor action. In this investigation, the effects of control fatty acids (oleic acid (OA), linoleic acid (LA)) and n-3 PUFA, e.g., docosahexaenoic acid (DHA) on the uptake and metabolism of the carcinogenic polycyclic aromatic hydrocarbon, benzo[a]pyrene (BaP) was investigated in A549 cells, a human adenocarcinoma alveolar basal epithelial cell line. A549 cells activate BaP through the cytochrome P450 enzyme system to form reactive metabolites, a few of which covalently bind to DNA and proteins. Therefore, multiphoton microscopy spectral analysis combined with linear unmixing was used to identify the parent compound and BaP metabolites formed in cells, in the presence and absence of fatty acids. The relative abundance of select metabolites was associated with altered P450 activity as determined using ethoxyresorufin-O-deethylase activity in cells cultured in the presence of BSA-conjugated fatty acids. In addition, the parent compound within cellular membranes increases significantly in the presence of each of the fatty acids, with the greatest accumulation observed following DHA treatment. DHA treated cells exhibit significantly lower pyrene-like metabolites indicative of lower adducts including DNA adducts compared to control BSA, OA or LA treated cells. Further, DHA reduced the abundance of the proximate carcinogen BaP 7,8-dihydrodiol and the 3-hydroxybenzo[a]pyrene metabolites compared to other treatments. The significant changes in BaP metabolites in DHA treated cells may be mediated by the effects on the physicochemical properties of the membrane known to affect enzyme activity related to phase I and phase II metabolism. In summary, DHA is a highly bioactive chemo

  6. A relationship between vitamin B sub 12 , folic acid, ascorbic acid, and mercury uptake and methylation

    SciTech Connect

    Zorn, N.E.; Smith, J.T. )

    1990-01-01

    Ingestion of megadoses of certain vitamins appears to influence the in vivo methylation of mercuric chloride in guinea pigs. The addition of megadoses of vitamin B{sub 12} fed either singularly or in combination with folic acid resulted in increased methylmercury concentrations in the liver. Moreover, percent methylmercury levels were significantly increased with B{sub 12} treatment in the liver (B{sub 12} only and B{sub 12}/folic acid) and brain (B{sub 12}/vitamin C). Incorporation of high levels of folic acid into the dietary regime also increased the methylmercury concentration particularly in the liver and hair tissues. The addition of vitamin C in the diet, particularly in combination with B{sub 12} (brain) or folic acid (muscle) resulted in increased methylmercury levels in these tissues and percent methylmercury values with B{sub 12} in the muscle and brain tissue.

  7. Interaction of cinnamic acid derivatives with commercial hypoglycemic drugs on 2-deoxyglucose uptake in 3T3-L1 adipocytes.

    PubMed

    Prabhakar, Pranav Kumar; Doble, Mukesh

    2011-09-28

    Hydroxycinnamic acid derivatives are naturally occurring substances found in fruits, vegetables, and flowers and are consumed as dietary phenolic compounds. The effect of cinnamic acid, ferulic acid, p-coumaric acid, eugenol, chlorogenic acid, and caffeic acid, alone and in combination with two commercial oral hypoglycemic drugs (OHD), namely, thiazolidinedione (THZ) and metformin, on the uptake of 2-deoxyglucose (2DG) by 3T3-L1 adipocytes is studied. All of the phytochemicals other than cinnamic acid show synergistic interaction in 2DG uptake with both of the OHDs. THZ (20 μM) in combination with ferulic acid (25 μM) or p-coumaric acid (25 μM) increases 2DG uptake by 7- or 6.34-fold, respectively, with respect to control, whereas metformin (20 μM), along with ferulic acid (25 μM) or cinnamic acid (25 μM), increases 2DG uptake by 6.45- or 5.87-fold, respectively, when compared to control. Chlorogenic and cinnamic acids increased the expression of PPARγ, whereas other hydroxycinnamic acids enhanced the expression of PI3K, indicating different mechanisms of action between these compounds. These phytochemicals were able to reduce the expressions of the fatty acid synthase and HMG CoA reductase genes, indicating that they may be able to reduce the secondary complications caused by the accumulation of lipids. These studies suggest that hydroxycinnamic acid derivatives may be beneficial for the treatment of diabetes mellitus. They may act as a supplement with commercial drugs and may reduce the secondary complications caused by OHDs.

  8. Effect of citric acid and bacteria on metal uptake in reeds grown in a synthetic acid mine drainage solution.

    PubMed

    Guo, Lin; Cutright, Teresa J

    2015-03-01

    The effect of citric acid (CA), rhizosphere acidophilic heterotrophs and/or Fe(II) oxidizing bacteria (Fe(II)OB) on plaque formation and metal accumulation in Phragmites australis L. (common reed) from acid mine drainage (AMD) solution were investigated. Reeds were grown in different hydroponic solutions that contained AMD, CA and/or rhizosphere bacteria for three months. Triplicate experiments were conducted for each experimental condition. Fe(II)OB enhanced the formation of Fe plaque which decreased Fe and Mn uptake in reeds, while it had no significant influence on Al accumulation. CA inhibited the growth of Fe(II)OB, decreased the formation of metal plaque and increased Fe and Mn accumulation in reeds. Acidophilic heterotrophs consumed CA and made the environment more suitable for the growth of Fe(II)OB. Reeds are a good candidate for phytoextraction while CA is a useful chelator to enhance metal uptake in plants. More research may be needed to investigate the influence of CA on microbial community. Further investigations are required to study the effect of CA on phytoremediation of AMD contaminated fields.

  9. The Helicobacter pylori homologue of the ferric uptake regulator is involved in acid resistance.

    PubMed

    Bijlsma, Jetta J E; Waidner, Barbara; Vliet, Arnoud H M van; Hughes, Nicky J; Häg, Stephanie; Bereswill, Stefan; Kelly, David J; Vandenbroucke-Grauls, Christina M J E; Kist, Manfred; Kusters, Johannes G

    2002-02-01

    The only known niche of the human pathogen Helicobacter pylori is the gastric mucosa, where large fluctuations of pH occur, indicating that the bacterial response and resistance to acid are important for successful colonization. One of the few regulatory proteins in the H. pylori genome is a homologue of the ferric uptake regulator (Fur). In most bacteria, the main function of Fur is the regulation of iron homeostasis. However, in Salmonella enterica serovar Typhimurium, Fur also plays an important role in acid resistance. In this study, we determined the role of the H. pylori Fur homologue in acid resistance. Isogenic fur mutants were generated in three H. pylori strains (1061, 26695, and NCTC 11638). At pH 7 there was no difference between the growth rates of mutants and the parent strains. Under acidic conditions, growth of the fur mutants was severely impaired. No differences were observed between the survival of the fur mutant and parent strain 1061 after acid shock. Addition of extra iron or removal of iron from the growth medium did not improve the growth of the fur mutant at acidic pH. This indicates that the phenotype of the fur mutant at low pH was not due to increased iron sensitivity. Transcription of fur was repressed in response to low pH. From this we conclude that Fur is involved in the growth at acidic pH of H. pylori; as such, it is the first regulatory protein implicated in the acid resistance of this important human pathogen. PMID:11796589

  10. Amino Acid Uptake and Metabolism of Legionella pneumophila Hosted by Acanthamoeba castellanii*

    PubMed Central

    Schunder, Eva; Gillmaier, Nadine; Kutzner, Erika; Herrmann, Vroni; Lautner, Monika; Heuner, Klaus; Eisenreich, Wolfgang

    2014-01-01

    Legionella pneumophila survives and replicates within a Legionella-containing vacuole (LCV) of amoebae and macrophages. Less is known about the carbon metabolism of the bacteria within the LCV. We have now analyzed the transfer and usage of amino acids from the natural host organism Acanthamoeba castellanii to Legionella pneumophila under in vivo (LCV) conditions. For this purpose, A. castellanii was 13C-labeled by incubation in buffer containing [U-13C6]glucose. Subsequently, these 13C-prelabeled amoebae were infected with L. pneumophila wild type or some mutants defective in putative key enzymes or regulators of carbon metabolism. 13C-Isotopologue compositions of amino acids from bacterial and amoebal proteins were then determined by mass spectrometry. In a comparative approach, the profiles documented the efficient uptake of Acanthamoeba amino acids into the LCV and further into L. pneumophila where they served as precursors for bacterial protein biosynthesis. More specifically, A. castellanii synthesized from exogenous [U-13C6]glucose unique isotopologue mixtures of several amino acids including Phe and Tyr, which were also observed in the same amino acids from LCV-grown L. pneumophila. Minor but significant differences were only detected in the isotopologue profiles of Ala, Asp, and Glu from the amoebal or bacterial protein fractions, respectively, indicating partial de novo synthesis of these amino acids by L. pneumophila. The similar isotopologue patterns in amino acids from L. pneumophila wild type and the mutants under study reflected the robustness of amino acid usage in the LCV of A. castellannii. PMID:24904060

  11. Nitrated fatty acids reverse pulmonary fibrosis by dedifferentiating myofibroblasts and promoting collagen uptake by alveolar macrophages

    PubMed Central

    Reddy, Aravind T.; Lakshmi, Sowmya P.; Zhang, Yingze; Reddy, Raju C.

    2014-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal disease, thought to be largely transforming growth factor β (TGFβ) driven, for which there is no effective therapy. We assessed the potential benefits in IPF of nitrated fatty acids (NFAs), which are unique endogenous agonists of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor that exhibits wound-healing and antifibrotic properties potentially useful for IPF therapy. We found that pulmonary PPARγ is down-regulated in patients with IPF. In vitro, knockdown or knockout of PPARγ expression in isolated human and mouse lung fibroblasts induced a profibrotic phenotype, whereas treating human fibroblasts with NFAs up-regulated PPARγ and blocked TGFβ signaling and actions. NFAs also converted TGFβ to inactive monomers in cell-free solution, suggesting an additional mechanism through which they may inhibit TGFβ. In vivo, treating mice bearing experimental pulmonary fibrosis with NFAs reduced disease severity. Also, NFAs up-regulated the collagen-targeting factor milk fat globule-EGF factor 8 (MFG-E8), stimulated collagen uptake and degradation by alveolar macrophages, and promoted myofibroblast dedifferentiation. Moreover, treating mice with established pulmonary fibrosis using NFAs reversed their existing myofibroblast differentiation and collagen deposition. These findings raise the prospect of treating IPF with NFAs to halt and perhaps even reverse the progress of IPF.—Reddy, A. T., Lakshmi, S. P., Zhang, Y., Reddy, R. C. Nitrated fatty acids reverse pulmonary fibrosis by dedifferentiating myofibroblasts and promoting collagen uptake by alveolar macrophages. PMID:25252739

  12. Phytochrome controlled C-sucrose uptake into etiolated pea buds: effects of gibberellic Acid and other substances.

    PubMed

    Goren, R; Galston, A W

    1967-08-01

    The previously reported red light enhancement of (14)C-sucrose uptake into etiolated pea buds is inhibited by gibberellic acid applied no later than 2 hours after the light. Auxins, cytokinins and inhibitors of gibberellin biosynthesis are without effect, either alone or in the presence of gibberellic acid. PMID:16656618

  13. Increased brain uptake of targeted nanoparticles by adding an acid-cleavable linkage between transferrin and the nanoparticle core.

    PubMed

    Clark, Andrew J; Davis, Mark E

    2015-10-01

    Most therapeutic agents are excluded from entering the central nervous system by the blood-brain barrier (BBB). Receptor mediated transcytosis (RMT) is a common mechanism used by proteins, including transferrin (Tf), to traverse the BBB. Here, we prepared Tf-containing, 80-nm gold nanoparticles with an acid-cleavable linkage between the Tf and the nanoparticle core to facilitate nanoparticle RMT across the BBB. These nanoparticles are designed to bind to Tf receptors (TfRs) with high avidity on the blood side of the BBB, but separate from their multidentate Tf-TfR interactions upon acidification during the transcytosis process to allow release of the nanoparticle into the brain. These targeted nanoparticles show increased ability to cross an in vitro model of the BBB and, most important, enter the brain parenchyma of mice in greater amounts in vivo after systemic administration compared with similar high-avidity nanoparticles containing noncleavable Tf. In addition, we investigated this design with nanoparticles containing high-affinity antibodies (Abs) to TfR. With the Abs, the addition of the acid-cleavable linkage provided no improvement to in vivo brain uptake for Ab-containing nanoparticles, and overall brain uptake was decreased for all Ab-containing nanoparticles compared with Tf-containing ones. These results are consistent with recent reports of high-affinity anti-TfR Abs trafficking to the lysosome within BBB endothelium. In contrast, high-avidity, Tf-containing nanoparticles with the acid-cleavable linkage avoid major endothelium retention by shedding surface Tf during their transcytosis. PMID:26392563

  14. Increased brain uptake of targeted nanoparticles by adding an acid-cleavable linkage between transferrin and the nanoparticle core.

    PubMed

    Clark, Andrew J; Davis, Mark E

    2015-10-01

    Most therapeutic agents are excluded from entering the central nervous system by the blood-brain barrier (BBB). Receptor mediated transcytosis (RMT) is a common mechanism used by proteins, including transferrin (Tf), to traverse the BBB. Here, we prepared Tf-containing, 80-nm gold nanoparticles with an acid-cleavable linkage between the Tf and the nanoparticle core to facilitate nanoparticle RMT across the BBB. These nanoparticles are designed to bind to Tf receptors (TfRs) with high avidity on the blood side of the BBB, but separate from their multidentate Tf-TfR interactions upon acidification during the transcytosis process to allow release of the nanoparticle into the brain. These targeted nanoparticles show increased ability to cross an in vitro model of the BBB and, most important, enter the brain parenchyma of mice in greater amounts in vivo after systemic administration compared with similar high-avidity nanoparticles containing noncleavable Tf. In addition, we investigated this design with nanoparticles containing high-affinity antibodies (Abs) to TfR. With the Abs, the addition of the acid-cleavable linkage provided no improvement to in vivo brain uptake for Ab-containing nanoparticles, and overall brain uptake was decreased for all Ab-containing nanoparticles compared with Tf-containing ones. These results are consistent with recent reports of high-affinity anti-TfR Abs trafficking to the lysosome within BBB endothelium. In contrast, high-avidity, Tf-containing nanoparticles with the acid-cleavable linkage avoid major endothelium retention by shedding surface Tf during their transcytosis.

  15. Propionic acid and butyric acid inhibit lipolysis and de novo lipogenesis and increase insulin-stimulated glucose uptake in primary rat adipocytes.

    PubMed

    Heimann, Emilia; Nyman, Margareta; Degerman, Eva

    2015-01-01

    Fermentation of dietary fibers by colonic microbiota generates short-chain fatty acids (SCFAs), e.g., propionic acid and butyric acid, which have been described to have "anti-obesity properties" by ameliorating fasting glycaemia, body weight and insulin tolerance in animal models. In the present study, we therefore investigate if propionic acid and butyric acid have effects on lipolysis, de novo lipogenesis and glucose uptake in primary rat adipocytes. We show that both propionic acid and butyric acid inhibit isoproterenol- and adenosine deaminase-stimulated lipolysis as well as isoproterenol-stimulated lipolysis in the presence of a phosphodiesterase (PDE3) inhibitor. In addition, we show that propionic acid and butyric acid inhibit basal and insulin-stimulated de novo lipogenesis, which is associated with increased phosphorylation and thus inhibition of acetyl CoA carboxylase, a rate-limiting enzyme in fatty acid synthesis. Furthermore, we show that propionic acid and butyric acid increase insulin-stimulated glucose uptake. To conclude, our study shows that SCFAs have effects on fat storage and mobilization as well as glucose uptake in rat primary adipocytes. Thus, the SCFAs might contribute to healthier adipocytes and subsequently also to improved energy metabolism with for example less circulating free fatty acids, which is beneficial in the context of obesity and type 2 diabetes. PMID:26167409

  16. Nanomolar Caffeic Acid Decreases Glucose Uptake and the Effects of High Glucose in Endothelial Cells

    PubMed Central

    Natarelli, Lucia; Ranaldi, Giulia; Leoni, Guido; Roselli, Marianna; Guantario, Barbara; Comitato, Raffaella; Ambra, Roberto; Cimino, Francesco; Speciale, Antonio; Virgili, Fabio; Canali, Raffaella

    2015-01-01

    Epidemiological studies suggest that moderate and prolonged consumption of coffee is associated with a reduced risk of developing type 2 diabetes but the molecular mechanisms underlying this effect are not known. In this study, we report the effects of physiological concentrations of caffeic acid, easily achievable by normal dietary habits, in endothelial cells cultured in 25 mM of glucose (high glucose, HG). In HG, the presence of 10 nM caffeic acid was associated with a decrease of glucose uptake but not to changes of GLUT-1 membrane localization or mRNA levels. Moreover, caffeic acid countered HG-induced loss of barrier integrity, reducing actin rearrangement and FITC-dextran passage. The decreased flux of glucose associated to caffeic acid affected HG induced apoptosis by down-regulating the expression of initiator (caspase 8 and 9) and effector caspases (caspase 7 and 3) and by increasing the levels of phosphorylated Bcl-2. We also observed that caffeic acid in HG condition was associated to a reduction of p65 subunit nuclear levels with respect to HG alone. NF-κB activation has been shown to lead to apoptosis in HG treated cells and the analysis of the expression of a panel of about 90 genes related to NF-κB signaling pathway revealed that caffeic acid significantly influenced gene expression changes induced by HG. In conclusion, our results suggest that caffeic acid, decreasing the metabolic stress induced by HG, allows the activation of survival mechanisms mediated by a different modulation of NF-κB-related signaling pathways and to the activation of anti-apoptotic proteins. PMID:26544184

  17. Water uptake of internally mixed ammonium sulfate and dicarboxylic acid particles probed by infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Miñambres, Lorena; Méndez, Estíbaliz; Sánchez, María N.; Castaño, Fernando; Basterretxea, Francisco J.

    2013-05-01

    Tropospheric aerosols are usually mixtures of inorganic and organic compounds in variable proportions, and the relative amount of organic fraction can influence the hygroscopic properties of the particles. Infrared spectra of submicrometer internally mixed dry particles of ammonium sulfate (AS) with various dicarboxylic acids (oxalic, malonic, maleic, glutaric and pimelic) have been measured in an aerosol flow tube at several solute mass ratios. The spectra show a notable broadening in the bandwidth of sulfate ion ν3 vibrational band near 1115 cm-1 with respect to pure AS. We attribute these perturbations, that are biggest at AS/organic acid mass ratio near unity, to intermolecular interactions between inorganic ions and organic acid molecules in the internally mixed solids. The water uptake behavior of internally mixed particles has been measured by recording the infrared integrated absorbance of liquid water as a function of relative humidity (RH). The amount of water present in the particles prior to deliquescence correlates partially with the water solubilities of the dicarboxylic acids, and also with the relative magnitudes of intermolecular interactions in the internally mixed dry solids. Phase change of ammonium sulfate in the internally mixed particles with RH has been spectrally monitored, and it is shown that water uptaken before full deliquescence produces structural changes in the particles that are revealed by their vibrational spectra.

  18. Loss of intracellular lipid binding proteins differentially impacts saturated fatty acid uptake and nuclear targeting in mouse hepatocytes.

    PubMed

    Storey, Stephen M; McIntosh, Avery L; Huang, Huan; Martin, Gregory G; Landrock, Kerstin K; Landrock, Danilo; Payne, H Ross; Kier, Ann B; Schroeder, Friedhelm

    2012-10-01

    The liver expresses high levels of two proteins with high affinity for long-chain fatty acids (LCFAs): liver fatty acid binding protein (L-FABP) and sterol carrier protein-2 (SCP-2). Real-time confocal microscopy of cultured primary hepatocytes from gene-ablated (L-FABP, SCP-2/SCP-x, and L-FABP/SCP-2/SCP-x null) mice showed that the loss of L-FABP reduced cellular uptake of 12-N-methyl-(7-nitrobenz-2-oxa-1,3-diazo)-aminostearic acid (a fluorescent-saturated LCFA analog) by ∼50%. Importantly, nuclear targeting of the LCFA was enhanced when L-FABP was upregulated (SCP-2/SCP-x null) but was significantly reduced when L-FABP was ablated (L-FABP null), thus impacting LCFA nuclear targeting. These effects were not associated with a net decrease in expression of key membrane proteins involved in LCFA or glucose transport. Since hepatic LCFA uptake and metabolism are closely linked to glucose uptake, the effect of glucose on L-FABP-mediated LCFA uptake and nuclear targeting was examined. Increasing concentrations of glucose decreased cellular LCFA uptake and even more extensively decreased LCFA nuclear targeting. Loss of L-FABP exacerbated the decrease in LCFA nuclear targeting, while loss of SCP-2 reduced the glucose effect, resulting in enhanced LCFA nuclear targeting compared with control. Simply, ablation of L-FABP decreases LCFA uptake and even more extensively decreases its nuclear targeting.

  19. 21 CFR 862.1715 - Triiodothyronine uptake test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of...

  20. 21 CFR 862.1715 - Triiodothyronine uptake test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of...

  1. 21 CFR 862.1715 - Triiodothyronine uptake test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of...

  2. 21 CFR 862.1715 - Triiodothyronine uptake test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of...

  3. 21 CFR 862.1715 - Triiodothyronine uptake test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... albumin of serum and plasma. The device provides an indirect measurement of thyrkoxine levels in serum and plasma. Measurements of triiodothyronine uptake are used in the diagnosis and treatment of...

  4. Uptake of silica covered Quantum Dots into living cells: Long term vitality and morphology study on hyaluronic acid biomaterials.

    PubMed

    D'Amico, Michele; Fiorica, Calogero; Palumbo, Fabio Salvatore; Militello, Valeria; Leone, Maurizio; Dubertret, Benoit; Pitarresi, Giovanna; Giammona, Gaetano

    2016-10-01

    Quantum Dots (QDs) are promising very bright and stable fluorescent probes for optical studies in the biological field but water solubility and possible metal bio-contamination need to be addressed. In this work, a simple silica-QD hybrid system is prepared and the uptake in bovine chondrocytes living cells without any functionalization of the external protective silica shield is demonstrated. Moreover, long term treated cells vitality (up to 14days) and the transfer of silica-QDs to the next cell generations are here reported. Confocal fluorescence microscopy was also used to determine the morphology of the so labelled cells and the relative silica-QDs distribution. Finally, we employ silica-QD stained chondrocytes to characterize, as proof of concept, hydrogels obtained from an amphiphilic derivative of hyaluronic acid (HA-EDA-C18) functionalized with different amounts of the RGD peptide. PMID:27287118

  5. Uptake of silica covered Quantum Dots into living cells: Long term vitality and morphology study on hyaluronic acid biomaterials.

    PubMed

    D'Amico, Michele; Fiorica, Calogero; Palumbo, Fabio Salvatore; Militello, Valeria; Leone, Maurizio; Dubertret, Benoit; Pitarresi, Giovanna; Giammona, Gaetano

    2016-10-01

    Quantum Dots (QDs) are promising very bright and stable fluorescent probes for optical studies in the biological field but water solubility and possible metal bio-contamination need to be addressed. In this work, a simple silica-QD hybrid system is prepared and the uptake in bovine chondrocytes living cells without any functionalization of the external protective silica shield is demonstrated. Moreover, long term treated cells vitality (up to 14days) and the transfer of silica-QDs to the next cell generations are here reported. Confocal fluorescence microscopy was also used to determine the morphology of the so labelled cells and the relative silica-QDs distribution. Finally, we employ silica-QD stained chondrocytes to characterize, as proof of concept, hydrogels obtained from an amphiphilic derivative of hyaluronic acid (HA-EDA-C18) functionalized with different amounts of the RGD peptide.

  6. Molecular hydrogen attenuates fatty acid uptake and lipid accumulation through downregulating CD36 expression in HepG2 cells

    PubMed Central

    2013-01-01

    Background There is accumulating evidence that obesity is closely associated with an impaired free fatty acid metabolism as well as with insulin resistance and inflammation. Excessive fatty acid uptake mediated by fatty acid translocase CD36 plays an important role in hepatic steatosis. Molecular hydrogen has been shown to attenuate oxidative stress and improve lipid, glucose and energy metabolism in patients and animal models of hepatic steatosis and atherosclerosis, but the underlying molecular mechanisms remain largely unknown. Methods Human hepatoma HepG2 cells were exposed to palmitate-BSA complex after treatment with or without hydrogen for 24 h. The fatty acid uptake was measured by using spectrofluorometry and the lipid content was detected by Oil Red O staining. JNK phosphorylation and CD36 expression were analyzed by Western blot and real-time PCR analyses. Results Pretreatment with hydrogen reduced fatty acid uptake and lipid accumulation after palmitate overload in HepG2 cells, which was associated with inhibition of JNK activation. Hydrogen treatment did not alter CD36 mRNA expression but reduced CD36 protein expression. Conclusion Hydrogen inhibits fatty acid uptake and lipid accumulation through the downregulation of CD36 at the protein level in hepatic cultured cells, providing insights into the molecular mechanism underlying the hydrogen effects in vivo on lipid metabolism disorders. PMID:23448206

  7. Nitrogen uptake over entire root systems of tree seedlings.

    PubMed

    Hawkins, B J; Robbins, S; Porter, R B

    2014-04-01

    Uptake of nitrogen (N) by sequential root regions in six tree species was measured in roots of 16- to 26-month-old seedlings at 50 and 1500 µM NH4NO3 concentration, at the cell level using oscillating microelectrodes and at the root region level using enriched (15)N application. Our objective was to determine the root regions making the greatest contribution to total N uptake in each species as measured by the two contrasting techniques. White and condensed tannin zones were the regions with the smallest surface area in all species, but these zones often had the highest net flux of NH4(+) and NO3(-). For most species, little variation was found among root regions in N flux calculated using a (15)N mass balance approach, but where significant differences existed, high N flux was observed in white, cork or woody zones. When N fluxes measured by each of the two methods were multiplied by the estimated surface area or biomass of each root region, the effect of root region size had the greatest influence on regional N uptake. Root regions of greatest overall N uptake were the cork and woody zones, on average. Total N uptake may thus be greatest in older regions of tree seedling roots, despite low rates of uptake per unit area. PMID:24591287

  8. A novel glyceryl monoolein-bearing cubosomes for gambogenic acid: Preparation, cytotoxicity and intracellular uptake.

    PubMed

    Luo, Qing; Lin, Tongyuan; Zhang, Cai Yuan; Zhu, Tingting; Wang, Lei; Ji, Zhaojie; Jia, Buyun; Ge, Tao; Peng, Daiyin; Chen, Weidong

    2015-09-30

    Lyotropic cubic liquid crystalline nanoparticles, also known as 'cubosomes', have been tested as effective carriers for a variety of drugs due to their ability to enhance delivery efficiency and reduced drug side effects. Cubosomes are colloidal carriers composed of biodegradable Glyceryl monooleate and F127. Being composed of well tolerable and physiological materials, these carriers are well tolerated, compatible and non-toxic. In this study, therefore, we developed a novel, water-soluble, glyceryl monooleate and F127 based multiblock copolymer for Gambogenic acid (GNA) by emulsion-evaporation and low temperature-solidification technique. Physicochemical properties, in vitro cytotoxicity, cellular uptake and in vivo pharmacokinetic of GNA-loaded cubosomes (GNA-Cubs) were investigated. The results revealed that GNA-Cubs were spherical or ellipsoidal monocellular by dynamic light scattering, meanwhile, 150-250nm in mean size with narrow polydispersity indexas determined by transmission electron microscopy. Small angle X-ray scattering indicated that GNA-Cubs retain the Pn3m cubic symmetry. Compared with GNA solution, GNA-Cubs exhibited markedly prolonged inhibitory activity in SMMC-7721 cells, as well as time-dependent increases in intra-cellular uptake. Furthermore, in vivo pharmacokinetic study showed that the Cmax values and the AUC of GNA-Cubs were higher than GNA solution approximately 1.2-fold and 9.1-fold, respectively. In conclusion, the results showed that the cubic liquid crystalline nanoparticles could be a potentially nanocarrier in the delivery of GNA for cancer therapy. PMID:26209071

  9. Unique uptake of acid-prepared mesoporous spheres by lung epithelial and mesothelioma cells.

    PubMed

    Blumen, Steven R; Cheng, Kai; Ramos-Nino, Maria E; Taatjes, Douglas J; Weiss, Daniel J; Landry, Christopher C; Mossman, Brooke T

    2007-03-01

    Lung cancers, malignant mesotheliomas (MM), and fibrosis are devastating diseases with limited treatment strategies, in part due to poorly-effective drug delivery to affected areas of lung. We hypothesized that acid-prepared mesoporous spheres (APMS) (1-2 microm diameter, 40 A pore size) might be effective vehicles for pulmonary chemotherapeutic drug delivery. To assess this, APMS, chemically modified with different surface molecules (lipid, a linker having a terminal amine group, a thiol group, or tetraethylene glycol [TEG]), were evaluated for uptake and possible cytotoxic effects after in vitro administration to murine alveolar epithelial Type II (C10) and human mesothelioma (MM) cells and after intrapleural or intranasal administration to C57Bl/6 mice. APMS coated with TEG (APMS-TEG) were most efficiently taken up by C10 and MM cells. The mechanism of cell uptake was rapid, actin-dependent, and did not involve clathrin- or caveolae-mediated mechanisms nor fusion of membrane-bound APMS with lysosomes. When injected intrapleurally in mice, APMS-TEG were taken up by both CD45-positive and -negative cells of the diaphragm, lung, and spleen, whereas APMS administered by the intranasal route were predominantly in lung epithelial cells and alveolar macrophages. After intrapleural or intranasal administration, APMS were nonimmunogenic and nontoxic as evaluated by differential cell counts and lactate dehydrogenase levels in bronchoalveolar and pleural lavage fluids. In the treatment of lung and pleural diseases, APMS-TEG may be useful tools to deliver chemotherapeutic drugs or molecular constructs.

  10. Uptake of Cs and Sr radionuclides within oleic acid coated nanomagnetite-hematite composite

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, J.; Sengupta, Pranesh; Sen, D.; Mazumdar, S.; Tyagi, A. K.

    2015-12-01

    Nano-sized magnetic composite sorbent material like nanomagnetite - nanohematite has been synthesized for uptake of cesium and strontium ions from low level environmental effluents in effective decontamination from waste water. Synthesis of material was based on co-precipitation route and in situ coating of oleic acid on magnetite-hematite nanocomposite. Magnetic properties were studied for both the uncoated as prepared and coated nanocomposite materials. The magnetization curves showed no hysteresis or remnant magnetization. Both the materials exhibited super-paramagnetism. Saturation magnetization of the coated nanocomposite was found to be 30 emu/g whereas for as prepared nanocomposite it was 64 emu/g. Detailed characterizations of the materials was carried out by X ray diffraction and Transmission electron microscopic techniques and the grain sizes were found to vary between 10 and 15 nm range. Sorption experiments on cesium and strontium were carried out by batch mode equilibrium study. The uptake studies were performed by Atomic Absorption Spectroscopy for cesium ions and inductively coupled Plasma - Atomic Emission Spectroscopy for strontium ions. Size distributions of the particle were measure through Small Angle X ray Scattering (SAXS) experiment. Shifting in weak repulsive potential facilitates enhanced sorption for more period of time in stable condition in comparison of uncoated nanocomposite which forms larger aggregates.

  11. Root uptake and translocation of perfluorinated alkyl acids by three hydroponically grown crops.

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; De Voogt, Pim

    2014-04-16

    Tomato, cabbage, and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts (tomatoes, cabbage head, zucchinis) were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Root concentration factors were highest for long-chain PFAAs (>C11) in all three plant species, but these chemicals were not found in the edible parts. All other PFAAs were present in all above-ground plant parts, with transpiration stream concentration factors (TSCFs) of 0.05-0.25. These PFAAs are taken up with the transpiration stream and accumulate primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs.

  12. Root uptake and translocation of perfluorinated alkyl acids by three hydroponically grown crops.

    PubMed

    Felizeter, Sebastian; McLachlan, Michael S; De Voogt, Pim

    2014-04-16

    Tomato, cabbage, and zucchini plants were grown hydroponically in a greenhouse. They were exposed to 14 perfluorinated alkyl acids (PFAAs) at four different concentrations via the nutrient solution. At maturity the plants were harvested, and the roots, stems, leaves, twigs (where applicable), and edible parts (tomatoes, cabbage head, zucchinis) were analyzed separately. Uptake and transfer factors were calculated for all plant parts to assess PFAA translocation and distribution within the plants. Root concentration factors were highest for long-chain PFAAs (>C11) in all three plant species, but these chemicals were not found in the edible parts. All other PFAAs were present in all above-ground plant parts, with transpiration stream concentration factors (TSCFs) of 0.05-0.25. These PFAAs are taken up with the transpiration stream and accumulate primarily in the leaves. Although some systematic differences were observed, overall their uptake from nutrient solution to roots and their further distribution within the plants were similar between plant species and among PFAAs. PMID:24646206

  13. Uptake and release of adrenal ascorbic acid in the guinea pig after injection of ACTH

    SciTech Connect

    Kipp, D.E.; Rivers, J.M.

    1987-09-01

    The effect of a single injection of ACTH (3 IU/100 g body weight) on the distribution of ascorbic acid (AA) and radiolabeled AA in 20 tissues was studied in adult male guinea pigs consuming 500 mg AA/kg diet. Saline- or ACTH-injected animals were simultaneously injected with (1-/sup 14/C)AA, and killed at 0.5, 1, 2, 4 and 6 h after injection. There was no significant difference between treatments in the weight of any tissue over the 6-h experimental period. As anticipated, the concentration of AA in the adrenals of animals injected with ACTH was 33% of that of animals injected with saline at 4 h. Unexpectedly, the concentration of radiolabeled AA in the adrenals at 0.5 h after ACTH injection was 172% of that after saline injection. The concentration of radiolabeled AA in the adrenal of the saline-injected animals increased slowly over time to reach a level similar to that of ACTH-injected animals by 6 h. There was no effect of ACTH on the level of AA or uptake in any of the other tissues examined. These results demonstrate that a single dose of ACTH markedly influences the retention of AA in the adrenal gland without similarly altering retention of AA in other tissues. Furthermore, ACTH treatment causes both accelerated uptake and release of AA into the adrenals.

  14. Discordance between blood flow and fatty acid uptake in the myocardium following lactate infusion

    SciTech Connect

    Kiess, M.C.; Barlai-Kovach, M.M.; Elmaleh, D.; Strauss, H.W.

    1984-01-01

    The uptake of metabolic substrates by the heart is dependent, in part, on the concentration of alternative substrates in the blood. To determine the effect of increasing blood concentrations of lactate (L) on the myocardial concentration of fatty acid, studies were performed in 5 closed chest, anesthetized dogs. A modified fatty acid, 14-p-(I-123)iodophenyl beta methyl tetradecanoic acid (BMFA), which is taken up by the cell but does not undergo beta oxidation, was compared to Tl-201, a marker of perfusion. Two sets of measurements were made: (a) basal Tl and BMFA; followed by infusion of L and (b) reinjection of Tl and BMFA. Sequential 1 minute images were collected for 32 minutes after injection of each tracer, corrected for background activity, and analyzed to produce time/activity curves from the myocardium. A ratio of BMFA/Tl at 10 minutes after injection was calculated. BMFA/Tl was 1.33 +- 31 (mean +- SD) pre L and decreased to 0.72 +- 12 post L. The Tl values before and after L remained essentially unchanged. In conclusion, there is a discordance between myocardial blood flow (Tl) and BMFA distribution following L infusion. The change in BMFA/Tl ratio suggests that elevated L decreases BMFA concentration in the heart.

  15. Uptake of perfluoroalkyl acids in the leaves of coniferous and deciduous broad-leaved trees.

    PubMed

    Zhang, Huanhuan; Liu, Wei; He, Xin; Wang, Yu; Zhang, Qian

    2015-07-01

    Analytical methods for determining perfluoroalkyl acids (PFAAs) in leaves were developed to quantify a suite of analytes in both coniferous and deciduous broad-leaved trees. Sodium hydroxide-methanol and solid-phase extraction was selected as the extracting and cleanup strategy for PFAA analysis. Ten perfluorocarboxylic acids (PFCAs) and 4 perfluorosulfonic acids (PFSAs) were monitored in 7 kinds of leaves grown in the urban areas of Dalian, China. The results show that coniferous tree leaves take up more PFAAs than broad-leaved tree leaves, with the highest amount of 150 ng/g in pine needles. Leaf PFCA levels were much higher than PFSAs level. Short carbon-chain PFCAs with 3 to 6 perfluorinated carbons account for approximately 40% to 80% of the total leaf PFAAs, where uptake decreased with increasing carbon chain length. Temporal observation of leaf PFAAs revealed no significant variation of concentrations in the leaves over a weekly interval and the absence of significant seasonal change in pine needles and sophora. The present study provides some evidence for the accumulation of PFAAs in leaves, which is valuable for understanding their environmental behavior and the development of alternative bioindicator.

  16. Ursolic Acid Increases Glucose Uptake through the PI3K Signaling Pathway in Adipocytes

    PubMed Central

    He, Yonghan; Li, Wen; Li, Ying; Zhang, Shuocheng; Wang, Yanwen; Sun, Changhao

    2014-01-01

    Background Ursolic acid (UA), a triterpenoid compound, is reported to have a glucose-lowering effect. However, the mechanisms are not fully understood. Adipose tissue is one of peripheral tissues that collectively control the circulating glucose levels. Objective The objective of the present study was to determine the effect and further the mechanism of action of UA in adipocytes. Methods and Results The 3T3-L1 preadipocytes were induced to differentiate and treated with different concentrations of UA. NBD-fluorescent glucose was used as the tracer to measure glucose uptake and Western blotting used to determine the expression and activity of proteins involved in glucose transport. It was found that 2.5, 5 and 10 µM of UA promoted glucose uptake in a dose-dependent manner (17%, 29% and 35%, respectively). 10 µM UA-induced glucose uptake with insulin stimulation was completely blocked by the phosphatidylinositol (PI) 3-kinase (PI3K) inhibitor wortmannin (1 µM), but not by SB203580 (10 µM), the inhibitor of mitogen-activated protein kinase (MAPK), or compound C (2.5 µM), the inhibitor of AMP-activated kinase (AMPK) inhibitor. Furthmore, the downstream protein activities of the PI3K pathway, phosphoinositide-dependent kinase (PDK) and phosphoinositide-dependent serine/threoninekinase (AKT) were increased by 10 µM of UA in the presence of insulin. Interestingly, the activity of AS160 and protein kinase C (PKC) and the expression of glucose transporter 4 (GLUT4) were stimulated by 10 µM of UA under either the basal or insulin-stimulated status. Moreover, the translocation of GLUT4 from cytoplasm to cell membrane was increased by UA but decreased when the PI3K inhibitor was applied. Conclusions Our results suggest that UA stimulates glucose uptake in 3T3-L1 adipocytes through the PI3K pathway, providing important information regarding the mechanism of action of UA for its anti-diabetic effect. PMID:25329874

  17. [Separate evaluation of beta-methyl fatty acid uptake and perfusion in rat myocardium].

    PubMed

    Taniguchi, M; Bunkou, H; Nakajima, K; Taki, J; Muramori, A; Matsunari, I; Nambu, I; Shiirei, Y; Tonami, N; Hisada, K

    1989-12-01

    The kinetics and distribution of I-125 beta-methyl iodophenyl pentadecanoic acid (BMIPP) in rat's heart were studied for separate evaluation of perfusion and metabolism. Tl-201 and BMIPP were simultaneously injected. The experimental groups consisted of control (C), glucose (G) and sodium lactate loaded group (L). In C, myocardial uptake at 5 minutes after BMIPP injection was 3.60% ID/g and remained constant up to 60 minutes. The myocardium/lung ratio (2.44) and the myocardium/muscle ratio (4.55) of BMIPP were almost equal to those of Tl-201. But myocardium/liver ratio was low (1.31). In G, myocardial uptake of BMIPP (1.94 +/- 0.36% ID/g) and g-BMIPP/Tl (0.31 +/- 0.03) at 15 minutes after injection were significantly decreased (p less than 0.001) than those of C (3.16 +/- 0.18% ID/g and 0.48 +/- 0.05). In L. myocardial perfusion was decreased and g-BMIPP/Tl (0.73 +/- 0.14) was significantly higher (p less than 0.01) than those of C. Coefficient of variance of the density within a myocardium, and the ratio of inner to outer layer of myocardium (I/O ratio) were calculated from autoradiogram by videodensitometry. The myocardial distribution of BMIPP was more inhomogeneous, and the I/O ratio was lower than that of Tl-201, although these were not specific for metabolic interventions. In conclusion BMIPP is suitable for SPECT imaging and dual nuclide imaging by BMIPP and Tl-201 will provide informations about myocardial fatty acid metabolism and perfusion. PMID:2622083

  18. Uptake and distribution of a labeled fatty acid in a canine model of ischemia with and without reperfusion

    SciTech Connect

    Devous, M.D. Sr.

    1985-05-01

    The relationship between regional myocardial blood flow (RMBF) and the regional distribution of 15-(4-iodophenyl)-9-methyl pentadecanoic acid (9-MPDA) was studied in a canine model of myocardial ischemia with and without reperfusion. Group 1 dogs received 135 min of left anterior descending coronary artery (LAD) occlusion; Group 2 dogs received 90 min of LAD occlusion and 45 min of reflow; and Group 3 dogs received 90 min of LAD occlusion and 3.5 hr of reperfusion. All animals received 9-MPDA 15 min prior to sacrifice, and tracer microspheres prior to occlusion, 5 and 80 min after occlusion, 15 min after reperfusion, and 15 min before the end of reperfusion. In Group 1 (permanent ischemia), 9-MPDA distribution was closely correlated with RMBF both 5 and 80 min after occlusion. In Group 2, 9-MPDA uptake was most closely correlated with reperfusion RMBF rather than ischemic RMBF. However, in 1 animal with good reperfusion, 9-MPDA uptake was reduced and was correlated with ischemic blood flow measured 5 min after occlusion. In Group 3, 9-MPDA uptake was correlated with RMBF measured during the ischemic period and not with reperfusion RMBF. It appears that 9-MPDA uptake is determined by RMBF when flow is limited, or early in reperfusion. With prolonged reperfusion, 9-MPDA uptake is significantly reduced in the ischemic zone in the presence of normal flow. This finding implies that the uptake of this fatty acid during reperfusion is related to myocardial damage (myocardial metabolism.) and not to RMBF.

  19. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  20. Manganese accumulation in membrane fractions of primary astrocytes is associated with decreased γ-aminobutyric acid (GABA) uptake, and is exacerbated by oleic acid and palmitate.

    PubMed

    Fordahl, Steve C; Erikson, Keith M

    2014-05-01

    Manganese (Mn) exposure interferes with GABA uptake; however, the effects of Mn on GABA transport proteins (GATs) have not been identified. We sought to characterize how Mn impairs GAT function in primary rat astrocytes. Astrocytes exposed to Mn (500 μM) had significantly reduced (3)H-GABA uptake despite no change in membrane or cytosolic GAT3 protein levels. Co-treatment with 100 μM oleic or palmitic acids (both known to be elevated in Mn neurotoxicity), exacerbated the Mn-induced decline in (3)H-GABA uptake. Mn accumulation in the membrane fraction of astrocytes was enhanced with fatty acid administration, and was negatively correlated with (3)H-GABA uptake. Furthermore, control cells exposed to Mn only during the experimental uptake had significantly reduced (3)H-GABA uptake, and the addition of GABA (50 μM) blunted cytosolic Mn accumulation. These data indicate that reduced GAT function in astrocytes is influenced by Mn and fatty acids accumulating at or interacting with the plasma membrane.

  1. Characterization of cesium uptake mediated by a potassium transport system of bacteria in a soil conditioner.

    PubMed

    Zhang, Pengyao; Idota, Yoko; Yano, Kentaro; Negishi, Masayuki; Kawabata, Hideaki; Arakawa, Hiroshi; Morimoto, Kaori; Tsuji, Akira; Ogihara, Takuo

    2014-01-01

    We found that bacteria in a commercial soil conditioner sold in Ishinomaki, Miyagi, exhibited concentrative and saturable cesium ion (Cs(+)) uptake in the natural range of pH and temperature. The concentration of intracellular Cs(+) could be condensed at least a few times higher compared with the outside medium of the cells. This uptake appeared to be mediated by a K(+) transport system, since Cs(+) uptake was dose-dependently inhibited by potassium ion (K(+)). Eadie-Hofstee plot analysis indicated that the Cs(+) uptake involved a single saturable process. The maximum uptake amount (Jmax) was the same in the presence and absence of K(+), suggesting that Cs(+) and K(+) uptakes were competitive with respect to each other. These bacteria might be useful for bioremediation of cesium-contaminated soil.

  2. Amino acid uptake by yeasts. IV. Effect of thiol reagents on L-leucine transport in Saccharomyces cerevisiae.

    PubMed

    Ramos, E H; De Bongioanni, L C; Wainer, S R; Stoppani, A O

    1983-06-10

    (1) N-Ethylmaleimide (a penetrating SH- reagent) inactivated L-[14C]leucine entrance (binding and translocation) into Saccharomyces cerevisiae, the extent of inhibition depending on the time of preincubation with N-ethylmaleimide, N-ethylmaleimide concentration, the amino acid external and internal concentration, and the energization state of the yeast cells. With D-glucose-energized yeast, N-ethylmaleimide inhibited L-[14C]leucine entrance in all the assayed experimental conditions, but with starved yeast and low (0.1 mM) amino acid concentration, it did not inhibit L-[14C]leucine binding, except when the cells were preincubated with L-leucine. With the rho- respiratory-deficient mutant (energized cells), N-ethylmaleimide inhibited L-[14C]leucine entrance as with the energized wild-type, though to a lesser extent. (2) Analysis of the N-ethylmaleimide effect as a function of L-[14C]leucine concentration showed a significant decrease of Jmax values of the high- (S1) and low- (S2) affinity amino acid transport systems, but KT values were not significantly modified. (3) When assayed in the presence of D-glucose, N-ethylmaleimide inhibition of D-glucose uptake and respiration contributed significantly to inactivation of L-[14C]leucine entrance. Pretreatment of yeast cells with 2,4-dinitrophenol enhanced the effect of L-[14C]leucine binding and translocation. (4) Bromoacetylsulfanilic acid and bromoacetylaminoisophthalic acid, two non-penetrating SH- reagents, did not inactivate L-[14C]leucine entrance, while p-chloromercuribenzoate, a slowly penetrating SH-reagent, inactivated it to a limited extent. When compared with the effect of N-ethylmaleimide, these negative results indicate that thiol groups of the L-[14C]leucine carrier were not exposed on the outer surface of the yeast cell permeability barrier.

  3. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  4. Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

    SciTech Connect

    Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

    1989-01-01

    Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patients with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake.

  5. Composite polymeric beads containing N,N,N',N'-tetraoctyldiglycolamide for actinide ion uptake from nitric acid feeds: Batch uptake, kinetic modelling and column studies.

    PubMed

    Gujar, R B; Mohapatra, P K; Lakshmi, D Shanthana; Figoli, A

    2015-11-27

    Polyethersulphone (PES) based composite polymeric beads (CPB) containing TODGA (N,N,N',N'-tetraoctyldiglycolamide) as the extractant were prepared by conventional phase inversion technique and were tested for the uptake of actinide ions such as Am(3+), UO2(2+), Pu(4+), Np(4+) and fission product ions such as Eu(3+) and Sr(2+). The CPBs containing 2.5-10wt.% TODGA were characterized by various physical methods and their porosity, size, surface morphology, surface area and the degradation profile by thermogravimetry were analyzed. The batch uptake studies involved kinetics of metal ion sorption, uptake as a function of nitric acid concentration, kinetic modelling and adsorption isotherms and most of the studies involved the Am(3+) ions. The batch saturation sorption capacities for Eu(3+) loading at 3M HNO3 were determined to be 6.6±0.02, 9.1±0.02 and 22.3±0.04mgg(-1) of CRBs with 2.5wt.%, 5wt.% and 10wt.% TODGA, respectively. The sorption isotherm analysis with Langmuir, D-R and Freundlisch isotherms indicated chemisorption monolayer mechanism. Chromatographic studies indicated breakthrough of Eu(3+) (using a solution containing Eu carrier) after about 0.75 bed volume (3.5-4mL). Elution of the loaded Eu was carried out using 0.01M EDTA as the eluent.

  6. Arsenic uptake by Lemna minor in hydroponic system.

    PubMed

    Goswami, Chandrima; Majumder, Arunabha; Misra, Amal Kanti; Bandyopadhyay, Kaushik

    2014-01-01

    Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved atinitial concentration of 0.5 mg/1 arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration.

  7. Arsenic uptake by Lemna minor in hydroponic system.

    PubMed

    Goswami, Chandrima; Majumder, Arunabha; Misra, Amal Kanti; Bandyopadhyay, Kaushik

    2014-01-01

    Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved atinitial concentration of 0.5 mg/1 arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration. PMID:24933913

  8. Effect of aspartame-derived phenylalanine on neutral amino acid uptake in human brain: a positron emission tomography study.

    PubMed

    Koeppe, R A; Shulkin, B L; Rosenspire, K C; Shaw, L A; Betz, A L; Mangner, T; Price, J C; Agranoff, B W

    1991-05-01

    The possible effects of elevation of the plasma phenylalanine level secondary to the ingestion of aspartame on brain amino acid uptake in human subjects have been investigated by means of positron emission tomography (PET). 1-[11C]Aminocyclohexanecarboxylate [( 11C]ACHC) is a poorly metabolized synthetic amino acid that crosses the blood-brain barrier by the same carrier that transports naturally occurring large neutral amino acids. Quantitative test-retest PET studies were performed on 15 individuals. Seven received two identical baseline scans, whereas eight received a baseline scan followed by a scan performed approximately 40-45 min following ingestion of an orange-flavored beverage containing 34 mg/kg of body weight of the low-calorie sweetener aspartame, a dose equivalent to the amount in 5 L of diet soft drink consumed all at once by the study subjects, weighing an average of 76 kg. The 40-45-min interval was selected to maximize the detection of possible decreases in ACHC uptake resulting from increased competition for the carrier, because the plasma phenylalanine level is known to peak at this time. We observed an 11.5% decrease in the amino acid transport rate constant K1 and a smaller decrease in the tissue distribution volume of ACHC (6%). Under conditions of normal dietary use, aspartame is thus unlikely to cause changes in brain amino acid uptake that are measurable by PET.

  9. Effects of Lipids on in Vitro Release and Cellular Uptake of β-Carotene in Nanoemulsion-Based Delivery Systems.

    PubMed

    Yi, Jiang; Zhong, Fang; Zhang, Yuzhu; Yokoyama, Wallace; Zhao, Liqing

    2015-12-23

    β-Carotene (BC) nanoemulsions were successfully prepared by microfluidization. BC micellarization was significantly affected by bile salts and pancreatin concentration. Positive and linear correlation was observed between BC release and bile salts concentration. Pancreatin facilitated BC's release in simulated digestion. Compared to the control (bulk oil) (4.6%), nanoemulsion delivery systems significantly improved the micellarization of BC (70.9%). The amount of BC partitioned into micelles was positively proportional to the length of carrier oils. Unsaturated fatty acid (UFA)-rich oils were better than saturated fatty acid (SFA)-rich oils in transferring BC (p < 0.05). No significant difference was observed between monounsaturated fatty acid (MUFA)-rich oils and polyunsaturated fatty acid (PUFA)-rich oils (p > 0.05). A positive and linear relationship between the degree of lipolysis and the release of BC in vitro digestion was observed. Bile salts showed cytotoxicity to Caco-2 cells below 20 times dilution. BC uptake by Caco-2 cells was not affected by fatty acid (FA) compositions in micelles, but BC uptake was proportional to its concentration in the diluted micelle fraction. The results obtained are beneficial to encapsulate and deliver BC or other bioactive lipophilic carotenoids in a wide range of commercial products. PMID:26629789

  10. Characterization of the Rhizobium (Sinorhizobium) meliloti high- and low-affinity phosphate uptake systems.

    PubMed Central

    Voegele, R T; Bardin, S; Finan, T M

    1997-01-01

    Genetic studies have suggested that Rhizobium (Sinorhizobium) meliloti contains two distinct phosphate (Pi) transport systems, encoded by the phoCDET genes and the orfA-pit genes, respectively. Here we present data which show that the ABC-type PhoCDET system has a high affinity for Pi (Km, 0.2 microM) and that Pi uptake by this system is severely inhibited by phosphonates. This high-affinity uptake system was induced under Pi-limiting conditions and was repressed in the presence of excess Pi. Uptake via the OrfA-Pit system was examined in (i) a phoC mutant which showed increased expression of the orfA-pit genes as a result of a promoter-up mutation and (ii) a phoB mutant (PhoB is required for phoCDET expression). Pi uptake in both strains exhibited saturation kinetics (Km, 1 to 2 microM) and was not inhibited by phosphonates. This uptake system was active in wild-type cells grown with excess Pi and appeared to be repressed when the cells were starved for Pi. Thus, our biochemical data show that the OrfA-Pit and PhoCDET uptake systems are differentially expressed depending on the state of the cell with respect to phosphate availability. PMID:9393684

  11. Modeling of immunoglobulin uptake by N,N,N',N'-ethylenediaminetetramethylenephosphonic acid-modified zirconia particles under static and dynamic conditions.

    PubMed

    Sarkar, Sabyasachi; Subramanian, Anuradha

    2005-07-01

    A matrix developed from N,N,N',N'-ethylenediaminetetramethylenephosphonic acid-modified zirconia beads (further referred to as r_PEZ); 25-38 microm in diameter and with a pore size of 22+/-3 nm, was utilized for the separation of immunoglobulins (Igs). r_PEZ has been shown to bind to various Igs originating from a wide variety of species. To understand the mechanisms controlling the uptake of Igs by r_PEZ, static protein uptake experiments were carried out. The protein uptake profiles were further modeled with a kinetic rate constant model. Individual studies were undertaken for human immunoglobulin A, G and M (HIgA, HIgG and HIgM). The kinetic rate constant model indicated that HIgG binding to r_PEZ was more favorable than its disassociation. The equilibrium rate constants were found to decrease with increasing concentration. The effect of continuous loading in a packed bed system utilizing r_PEZ matrix was evaluated by carrying out frontal studies, using different feed concentrations and linear velocities. The breakthrough profiles obtained for the uptake of HIgG were modeled with the pore diffusion model. The model was found to best describe the breakthrough profiles obtained at a feed concentration of 2.0 mg of HIgG per milliliter. The NTU for the packed bed was found to be equal to 2. PMID:15919247

  12. Uptake of gamma-aminobutyric acid and L-glutamic acid by synaptosomes from postmortem human cerebral cortex: multiple sites, sodium dependence and effect of tissue preparation.

    PubMed

    Dodd, P R; Watson, W E; Morrison, M M; Johnston, G A; Bird, E D; Cowburn, R F; Hardy, J A

    1989-06-26

    The uptake of gamma-aminobutyric acid (GABA) and L-glutamic acid by synaptosomes prepared from frozen postmortem human brain was shown to be effected via distinct high and low affinity sites. At approximately 17 h postmortem delay, the kinetic parameters for GABA uptake were: high affinity site, Km 7.1 +/- 2.5 microM, Vmax 18.7 +/- 4.8 nmol.min-1 per 100 mg protein; low affinity site, Km 2 +/- 1 mM, Vmax 425 +/- 250 nmol.min-1 per 100 mg protein (means +/- S.E.M., n = 13). Kinetic parameters for L-glutamate uptake were: high affinity site, Km 7.5 +/- 1.0 microM, Vmax 85 +/- 8 nmol.min-1 per 100 mg protein; low affinity site, Km 1.8 +/- 1.2 mM. Vmax 780 +/- 175 nmol.min-1 per 100 mg protein (n = 11). A detailed kinetic analysis of high affinity GABA uptake was performed over a range of sodium ion concentrations. The results were consistent with a coupling ratio of one Na+ ion to one GABA molecule; a similar result was found with rat brain synaptosomes. However, rat and human synaptosomes differed in the degree to which the substrate affinity of the high affinity GABA uptake site varied with decreasing Na+ ion concentration. High affinity GABA uptake was markedly affected by the method used to freeze and divide the tissue, but did not vary greatly in different cortical regions. There was some decline of high affinity GABA uptake activity with postmortem delay, apparently due to a loss of sites rather than a change in site affinity.

  13. Similarity in microbial amino acid uptake in surface waters of the North and South Atlantic (sub-)tropical gyres

    NASA Astrophysics Data System (ADS)

    Hill, Polly G.; Mary, Isabelle; Purdie, Duncan A.; Zubkov, Mikhail V.

    2011-12-01

    The Earth’s most extensive biomes - the oceanic subtropical gyres - are considered to be expanding with current surface ocean warming. Although it is well established that microbial communities control gyre biogeochemistry, comparisons of their metabolic activities between gyres are limited. In order to estimate metabolic activities including production of microbial communities, the uptake rates of amino acids leucine, methionine and tyrosine at ambient concentrations were estimated in surface waters of the Atlantic Ocean using radioisotopically labelled tracers. Data were acquired during six research cruises covering main oceanic provinces herein termed: North and South Atlantic Gyres, Bermuda Atlantic Time-series Study site (BATS), Equatorial region, and Mauritanian Upwelling (off Cape Blanc). Data were divided between provinces, the extents of which were identified by ocean colour data, in order to achieve provincial mean uptake rates. Leucine and methionine uptake rates did not differ between sampling periods, and were comparable between the North and South subtropical gyres. Furthermore, variation in uptake rates measured throughout the two oligotrophic gyres, where sampling covered ∼4 × 10 6 km 2, was considerably lower than that measured within the Mauritanian Upwelling and Equatorial regions, and even at the BATS site. Tyrosine was generally the slowest of the amino acids to be taken up, however, it was assimilated faster than methionine within the Mauritanian Upwelling region. Thus, we propose that one value for leucine (12.6 ± 3.2 pmol L -1 h -1) and methionine (10.0 ± 3.3 pmol L -1 h -1) uptake could be applied to the oligotrophic subtropical gyres of the Atlantic Ocean. However, with the significantly lower uptake rates observed at the BATS site, we would not advise extrapolation to the Sargasso Sea.

  14. Tracking amino acid's uptake into the protozoan Acanthamoeba castellanii by stable-isotope labelling and Raman spectral imaging

    NASA Astrophysics Data System (ADS)

    Naemat, Abida; Elsheikha, Hany M.; Notingher, Ioan

    2016-04-01

    The capacity of pathogens to acquire nutrients from their host cells is one of the most fundamental aspects of infection biology. Hence, measuring the patterns of nutrients' uptake by pathogens is essential for understanding the interactions of pathogens with eukaryotic host cells. In this study, we optimized a technique that allows fast and non-destructive measurement of the amino acid Phenylalanine (Phe) acquired by the trophozoite stage of the protozoan Acanthamoeba castellanii (A. castellanii) as they engage with individual human retinal pigment epithelial cells (ARPE-19). ARPE-19 host cells were pre-saturated with Deuterated Phe (L-Phe(D8)) to replace the native substrate Phe (L-Phe). The uptake of L-Phe(D8) by A. castellanii trophozoites was measured by Raman microspectroscopy. This approach allowed us to characterize the uptake patterns of this essential amino acid into A. castellanii trophozoites at a single cell level. At 24 hours post infection (PI) A. castellanii trophozoites are capable of salvaging L-Phe(D8) from host cells. The uptake pattern was time-dependent during the first 24 hours of infection and complete substitution with L-Phe(D8) in all parasites was detected at 48 hours PI. On the other hand, isolated A. castellanii trachyzoites (grown without host cells) did not show significant uptake for L-Phe(D8) from the media; only achieved an uptake ratio of 16-18% of L-Phe(D8) from the culture medium after 24 hours. These findings demonstrate the potential of combining Raman microspectroscopy and stable isotope labelling approaches to elucidate the role of metabolism in mediating A. castellanii interaction with host cells.

  15. Perfluoroalkyl acid uptake in lettuce (Lactuca sativa) and strawberry (Fragaria ananassa) irrigated with reclaimed water.

    PubMed

    Blaine, Andrea C; Rich, Courtney D; Sedlacko, Erin M; Hyland, Katherine C; Stushnoff, Cecil; Dickenson, Eric R V; Higgins, Christopher P

    2014-12-16

    Using reclaimed water to irrigate food crops presents an exposure pathway for persistent organic contaminants such as perfluoroalkyl acids (PFAAs) to enter the human food chain. This greenhouse study used reclaimed water augmented with varying concentrations (0.2-40 μg/L) of PFAAs, including perfluorocarboxylates (C3F7COO(-) to C8F17COO(-)) and perfluorosulfonates (C4F9SO2O(-), C6F13SO2O(-), C8F17SO2O(-)), to investigate potential uptake and concentration-response trends in lettuce (Lactuca sativa) and strawberry (Fragaria ananassa). In addition, studies were conducted to evaluate the role of soil organic carbon concentrations on plant uptake of PFAAs. PFAA concentrations in lettuce leaves and strawberry fruit were measured for each aqueous PFAA concentration applied. PFAA plant concentrations increased linearly with the aqueous concentration for all PFAAs, with PFCAs bioaccumulating to a greater degree than PFSAs in the edible portions of the tested plants. Chain-length-dependency trends were evident in both lettuce shoot and strawberry fruit, with decreasing concentrations associated with increasing chain length. Perfluorobutanoate (PFBA) and perfluoropentanoate (PFPeA), both short-chain PFAAs (<8 carbon chain length), accumulated the most compared with other PFAAs tested in the edible parts of both lettuce and strawberry. PFAA concentrations in strawberry root and shoot were also measured at selected PFAA aqueous concentrations (0.4, 4, and 40 μg/L). Short-chain perfluorocarboxylates were the dominant fraction in the strawberry fruit and shoot compartments, whereas a more even distribution of all PFAAs appeared in the root compartment. Lettuce grown in soils with varying organic carbon contents (0.4%, 2%, 6%) was used to assess the impact of organic carbon sorption on PFAA bioaccumulation. The lettuce grown in soil with the 6% organic carbon content had the lowest bioaccumulation of PFAAs. Bioaccumulation factors for lettuce were correlated to carbon chain

  16. The uptake of 2-methyl-3-buten-2-ol into aqueous mixed solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang; Yin, Shi; Tong, Shengrui

    2011-02-14

    Multiphase acid-catalyzed oxidation with hydrogen peroxide (H(2)O(2)) has been suggested recently to be a potential route to SOA formation from isoprene and its gas-phase oxidation products, the kinetics and chemical mechanism of this process have not been well-known yet. In this work, the uptake of 2-methyl-3-buten-2-ol (MBO), an important biogenic hydrocarbon and structurally similar to isoprene, into aqueous mixed solutions of H(2)O(2) and sulfuric acid (H(2)SO(4)) was performed using a rotated wetted-wall reactor coupled to a differentially pumped single-photon ionization time of flight mass spectrometer (RWW-SPI-TOFMS). The reactive uptake coefficients (γ) were acquired for the first time and the reaction pathways were deduced according to products information. The reactive uptake coefficients of MBO into H(2)SO(4)-H(2)O(2) mixed solutions are much greater than that into H(2)SO(4) solutions. Acetaldehyde, acetone and an on-line product, which transformed to isoprene readily in the duration of an off-line experiment, were suggested as products in this process. The further reactions of the carbonyl products can occur in acidic solution, which may play a role in SOA formation. Additionally, in real atmosphere the on-line product is apt to transform to isoprene, an acknowledged precursor of biogenic SOA. Thus, the multiphase acid-catalyzed oxidation of MBO with H(2)O(2) might be a potential contributor to SOA loading.

  17. [Uptake of 3-methyl-3-buten-1-ol into aqueous mixed solution of sulfuric acid and hydrogen peroxide].

    PubMed

    Wang, Tian-He; Liu, Ze; Ge, Mao-Fa; Wang, Wei-Gang

    2011-12-01

    Multiphase acid-catalyzed oxidation with hydrogen peroxide (H2O2) has been suggested recently to be a potential route to SOA formation, but the kinetics and chemical mechanism of this process have not been well-known yet. In this work, the uptake of 3-methyl-3-buten-1-ol (MBO331) into aqueous mixed solutions of H2O2, and sulfuric acid (H2SO4) was performed using a rotated wetted-wall reactor coupled to a VUV single-photon ionization time of flight mass spectrometer (VUV-SPI-TOFMS). The reactive uptake coefficients (gamma) were acquired for the first time and the reaction pathways were deduced according to products information. The uptake of MBO331 into H2SO4/H2O2 was fast, resulting in gamma reaching 2.52 x 10(-4)-1.05 x 10(-2) for 40%-60% H2SO4. Acetaldehyde, acetone and 3-methyl-3, 4-expoxybutane-1-ol were suggested as gas-phase products in this process. 3-methyl-3,4-expoxybutane-1-ol can transform into polyhydroxy compounds while the further reactions of the carbonyl products can occur in acidic solution, which may play a role in SOA formation. Thus, the heterogeneous acid-catalyzed oxidation of MBO331 with H2O2 might be a significant contributor to SOA loading.

  18. Docosahexaenoic acid in neural signaling systems.

    PubMed

    Crawford, Michael A

    2006-01-01

    Docosahexaenoic acid has been conserved in neural signalling systems in the cephalopods, fish, amphibian, reptiles, birds, mammals, primates and humans. This extreme conservation, despite wide genomic changes over 500 million years, testifies to a uniqueness of this molecule in the brain. The brain selectively incorporates docosahexaenoic acid and its rate of incorporation into the developing brain has been shown to be greater than ten times more efficient than its synthesis from the omega 3 fatty acids of land plant origin. Data has now been published demonstrating a significant influence of dietary omega 3 fatty acids on neural gene expression. As docosahexaenoic acid is the only omega 3 fatty acid in the brain, it is likely that it is the ligand involved. The selective uptake, requirement for function and stimulation of gene expression would have conferred an advantage to a primate which separated from the chimpanzees in the forests and woodlands and sought a different ecological niche. In view of the paucity of docosahexaenoic acid in the land food chain it is likely that the advantage would have been gained from a lacustrine or marine coastal habitat with access to food rich in docosahexaenoic acid and the accessory micronutrients, such as iodine, zinc, copper, manganese and selenium, of importance in brain development and protection against peroxidation. Land agricultural development has, in recent time, come to dominate the human food chain. The decline in use and availability of aquatic resources is not considered important by Langdon (2006) as he considers the resource was not needed for human evolution and can be replaced from the terrestrial food chain. This notion is not supported by the biochemistry nor the molecular biology. He misses the point that the shoreline hypothesis is not just dependent on docosahexaenoic acid but also on the other accessory nutrients specifically required by the brain. Moreover he neglects the basic principle of Darwinian

  19. Warming decreased and grazing increased plant uptake of amino acids in an alpine meadow.

    PubMed

    Ma, Shuang; Zhu, Xiaoxue; Zhang, Jing; Zhang, Lirong; Che, Rongxiao; Wang, Fang; Liu, Hanke; Niu, Haishan; Wang, Shiping; Cui, Xiaoyong

    2015-09-01

    Organic nitrogen (N) uptake by plants has been recognized as a significant component of terrestrial N cycle. Several studies indicated that plants have the ability to switch their preference between inorganic and organic forms of N in diverse environments; however, research on plant community response in organic nitrogen uptake to warming and grazing is scarce. Here, we demonstrated that organic N uptake by an alpine plant community decreased under warming with (13)C-(15)N-enriched glycine addition method. After 6 years of treatment, warming decreased plant organic N uptake by 37% as compared to control treatment. Under the condition of grazing, warming reduced plant organic N uptake by 44%. Grazing alone significantly increased organic N absorption by 15%, whereas under warming condition grazing did not affect organic N uptake by the Kobresia humilis community on Tibetan Plateau. Besides, soil NO 3-N content explained more than 70% of the variability observed in glycine uptake, and C:N ratio in soil dissolved organic matter remarkably increased under warming treatment. These results suggested warming promoted soil microbial activity and dissolved organic N mineralization. Grazing stimulated organic N uptake by plants, which counteracted the effect of warming. PMID:26442646

  20. Evaporation of water and uptake of HCl and HBr through hexanol films at the surface of supercooled sulfuric acid.

    PubMed

    Glass, Samuel V; Park, Seong-Chan; Nathanson, Gilbert M

    2006-06-22

    Vacuum evaporation and molecular beam scattering experiments have been used to monitor the loss of water and dissolution of HCl and HBr in deuterated sulfuric acid at 213 K containing 0 to 100 mM hexanol. The addition of 1-hexanol to the acid creates a surface film of hexyl species. This film becomes more compact with decreasing acidity, ranging from approximately 62% to approximately 68% of maximum packing on 68 to 56 wt % D(2)SO(4), respectively. D(2)O evaporation from 68 wt % acid remains unaltered by the hexyl film, where it is most porous, but is impeded by approximately 20% from 56 and 60 wt % acid. H --> D exchange experiments further indicate that the hexyl film on 68 wt % acid enhances conversion of HCl and HBr into DCl and DBr, which is interpreted as an increase in HCl and HBr entry into the bulk acid. For this permeable hexyl film, the hydroxyl groups of surface hexanol molecules may assist uptake by providing extra sites for HCl and HBr hydrogen bonding and dissociation. In contrast, HCl --> DCl exchange in 60 wt % D(2)SO(4) at first rises with hexyl surface coverage but then drops back to the bare acid value as the hexyl species pack more tightly. HCl entry is actually diminished by the hexyl film on 56 wt % acid, where the film is most compact. These experiments reveal a transition from a porous hexanol film on 68 wt % sulfuric acid that enhances HCl and HBr uptake to one on 56 wt % acid that slightly impedes HCl and D(2)O transport.

  1. Results of a combined model of root system growth and soil water uptake: evaluating the significance of root system architecture to plant water uptake

    NASA Astrophysics Data System (ADS)

    Bouda, M.; Saiers, J. E.

    2012-12-01

    Root system hydraulic architecture is a key determinant of plants' ability to withdraw water from the soil, satisfying transpirational demand. Presently, the representation of this component of the hydrological cycle in large-scale models is generally very simplistic, even though transpiration accounts for much of the terrestrial heat and water surface fluxes, and exercises control over photosynthetic uptake of CO2. In order to address this gap, we have developed a modelling approach that relies on several components. The first is RootGrow, original MATLAB code that simulates the stochastic growth of a root system as a function of an intrinsic set of parameters as well as its environment. We ran RootGrow coupled to the second component, a finite-element 3D simulation of the physics of water transport in the soil and root system using COMSOL, resulting in a combined model of root system development and water uptake. Model results show that root system architecture can affect water uptake by two separate mechanisms: (a) root system geometry determines the distribution of absorbing surface area throughout the soil domain, and (b) root system topology affects the water potential at the absorbing surfaces. In this study we sample the model's parameter space to demonstrate over what ranges of physically meaningful parameters (including hydraulic conductivity of plant tissues, soil type, and soil moisture level) these mechanisms significantly affect root systems' water withdrawal rate. The two mechanisms identified and our quantitative results will form the basis of a third component in this approach: developing simple analytical relationships characterising water uptake as a function of root system architecture that can be used in Ecosystem Demography Model v2.1 (ED2), a large-scale Dynamic Vegetation Model, based on a method of upscaling individual-based models of plant ecology.

  2. Water uptake properties of internally mixed sodium halide and succinic acid particles

    NASA Astrophysics Data System (ADS)

    Miñambres, Lorena; Méndez, Estíbaliz; Sánchez, María N.; Castaño, Fernando; Basterretxea, Francisco J.

    2011-10-01

    Sea salt aerosols include appreciable fractions of organic material, that can affect properties such as hygroscopicity, phase transition or chemical reactivity. Although sodium chloride is the major component of marine salt, bromide and iodide ions tend to accumulate onto particle surfaces and influence their behaviour. The hygroscopic properties of internally mixed submicrometric particles composed of succinic acid (SA) and NaX (where X = F, Cl, Br or I) have been studied by infrared absorption spectroscopy in an aerosol flow cell at ambient temperature for different relative succinic acid/NaX compositions. The results show that deliquescence relative humidities of SA/NaF and SA/NaCl are equal to those of the pure sodium halides. SA/NaBr particles, on the other hand, deliquesce at lower relative humidities than pure NaBr particles, the effect being more marked as the SA/NaBr mass ratio approaches unity. The SA/NaI system behaves as a non-deliquescent system, absorbing liquid water at all relative humidities, as in pure NaI. Succinic acid phase in the particles has been spectroscopically monitored at given values of both RH and SA/NaX solute mass ratio. The different hygroscopic properties as the halogen ion is changed can be rationalized in terms of simple thermodynamic arguments and can be attributed to the relative contributions of ion-molecule interactions in the solid particles. The observed behaviour is of interest for tropospheric sea salt aerosols mixed with organic acids.

  3. Iron uptake system mediates nitrate-facilitated cadmium accumulation in tomato (Solanum lycopersicum) plants.

    PubMed

    Luo, Bing Fang; Du, Shao Ting; Lu, Kai Xing; Liu, Wen Jing; Lin, Xian Yong; Jin, Chong Wei

    2012-05-01

    Nitrogen (N) management is a promising agronomic strategy to minimize cadmium (Cd) contamination in crops. However, it is unclear how N affects Cd uptake by plants. Wild-type and iron uptake-inefficient tomato (Solanum lycopersicum) mutant (T3238fer) plants were grown in pH-buffered hydroponic culture to investigate the direct effect of N-form on Cd uptake. Wild-type plants fed NO₃⁻ accumulated more Cd than plants fed NH₄⁺. Iron uptake and LeIRT1 expression in roots were also greater in plants fed NO₃⁻. However, in mutant T3238fer which loses FER function, LeIRT1 expression in roots was almost completely terminated, and the difference between NO₃⁻ and NH₄⁺ treatments vanished. As a result, the N-form had no effect on Cd uptake in this mutant. Furthermore, suppression of LeIRT1 expression by NO synthesis inhibition with either tungstate or L-NAME, also substantially inhibited Cd uptake in roots, and the difference between N-form treatments was diminished. Considering all of these findings, it was concluded that the up-regulation of the Fe uptake system was responsible for NO₃⁻-facilitated Cd accumulation in plants.

  4. Uptake of barbituric acid derivatives in small intestinal brush border membrane vesicles from retinyl palmitate-treated rats.

    PubMed

    Tanii, H; Horie, T

    2000-08-01

    Brush border membrane was prepared from the small intestinal (jejunum) cells along the crypt-villus axis. The fluorescence spectra of 1,8-anilinonaphthalene sulfonic acid and the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene were measured in the brush border membrane vesicle suspension. The hydrophobicity of brush border membrane was found to be in the order villus tip >mid villus >lower villus. The fluidity of brush border membrane was in the order villus tip uptake of barbituric acid derivatives by brush border membrane vesicles was well correlated with their partition coefficients (isopentyl acetate/water). No significant difference was observed between the uptake of hexobarbital by brush border membrane vesicles from the villus tip and lower villus. When retinyl palmitate was administered to rats, the fluidity of brush border membrane was found to be higher in the retinyl palmitate-treated rats than in the control rats. However, no significant difference in the uptake of hexobarbital by brush border membrane vesicles was observed between the retinyl palmitate-administered rats and the control rats. Thus, the retinyl palmitate treatment seems unlikely to affect the passively transported ligands like barbituric acid derivatives in brush border membrane vesicles. PMID:10989945

  5. Isoprene Epoxydiols as Precursors to Secondary Organic Aerosol Formation: Acid-Catalyzed Reactive Uptake Studies with Authentic Compounds

    PubMed Central

    Lin, Ying-Hsuan; Zhang, Zhenfa; Docherty, Kenneth S.; Zhang, Haofei; Budisulistiorini, Sri Hapsari; Rubitschun, Caitlin L.; Shaw, Stephanie L.; Knipping, Eladio M.; Edgerton, Eric S.; Kleindienst, Tadeusz E.; Gold, Avram; Surratt, Jason D.

    2011-01-01

    Isoprene epoxydiols (IEPOX), formed from the photooxidation of isoprene under low-NOx conditions, have recently been proposed as precursors of secondary organic aerosol (SOA) on the basis of mass spectrometric evidence. In the present study, IEPOX isomers were synthesized in high purity (> 99%) to investigate their potential to form SOA via reactive uptake in a series of controlled dark chamber studies followed by reaction product analyses. IEPOX-derived SOA was substantially observed only in the presence of acidic aerosols, with conservative lower-bound yields of 4.7–6.4% for β-IEPOX and 3.4–5.5% for δ-IEPOX, providing direct evidence for IEPOX isomers as precursors to isoprene SOA. These chamber studies demonstrate that IEPOX uptake explains the formation of known isoprene SOA tracers found in ambient aerosols, including 2-methyltetrols, C5-alkene triols, dimers, and IEPOX-derived organosulfates. Additionally, we show reactive uptake on the acidified sulfate aerosols supports a previously unreported acid-catalyzed intramolecular rearrangement of IEPOX to cis- and trans-3-methyltetrahydrofuran-3,4-diols (3-MeTHF-3,4-diols) in the particle phase. Analysis of these novel tracer compounds by aerosol mass spectrometry (AMS) suggests that they contribute to a unique factor resolved from positive matrix factorization (PMF) of AMS organic aerosol spectra collected from low-NOx, isoprene-dominated regions influenced by the presence of acidic aerosols. PMID:22103348

  6. Major involvement of Na(+) -dependent multivitamin transporter (SLC5A6/SMVT) in uptake of biotin and pantothenic acid by human brain capillary endothelial cells.

    PubMed

    Uchida, Yasuo; Ito, Katsuaki; Ohtsuki, Sumio; Kubo, Yoshiyuki; Suzuki, Takashi; Terasaki, Tetsuya

    2015-07-01

    The purpose of this study was to clarify the expression of Na(+) -dependent multivitamin transporter (SLC5A6/SMVT) and its contribution to the supply of biotin and pantothenic acid to the human brain via the blood-brain barrier. DNA microarray and immunohistochemical analyses confirmed that SLC5A6 is expressed in microvessels of human brain. The absolute expression levels of SLC5A6 protein in isolated human and monkey brain microvessels were 1.19 and 0.597 fmol/μg protein, respectively, as determined by a quantitative targeted absolute proteomics technique. Using an antibody-free method established by Kubo et al. (2015), we found that SLC5A6 was preferentially localized at the luminal membrane of brain capillary endothelium. Knock-down analysis using SLC5A6 siRNA showed that SLC5A6 accounts for 88.7% and 98.6% of total [(3) H]biotin and [(3) H]pantothenic acid uptakes, respectively, by human cerebral microvascular endothelial cell line hCMEC/D3. SLC5A6-mediated transport in hCMEC/D3 was markedly inhibited not only by biotin and pantothenic acid, but also by prostaglandin E2, lipoic acid, docosahexaenoic acid, indomethacin, ketoprofen, diclofenac, ibuprofen, phenylbutazone, and flurbiprofen. This study is the first to confirm expression of SLC5A6 in human brain microvessels and to provide evidence that SLC5A6 is a major contributor to luminal uptake of biotin and pantothenic acid at the human blood-brain barrier. In humans, it was unclear (not concluded) about what transport system at the blood-brain barrier (BBB) is responsible for the brain uptakes of two vitamins, biotin and pantothenic acid, which are necessary for brain proper function. This study clarified for the first time that the solute carrier 5A6/Na(+) -dependent multivitamin transporter SLC5A6/SMVT is responsible for the supplies of biotin and pantothenic acid into brain across the BBB in humans. DHA, docosahexaenoic acid; NSAID, non-steroidal anti-inflammatory drug; PGE2, prostaglandin E2.

  7. Selective and hyperactive uptake of foreign DNA by adaptive immune systems of an archaeon via two distinct mechanisms

    PubMed Central

    Erdmann, Susanne; Garrett, Roger A

    2012-01-01

    Central to the disparate adaptive immune systems of archaea and bacteria are clustered regularly interspaced short palindromic repeats (CRISPR). The spacer regions derive from invading genetic elements and, via RNA intermediates and associated proteins, target and cleave nucleic acids of the invader. Here we demonstrate the hyperactive uptake of hundreds of unique spacers within CRISPR loci associated with type I and IIIB immune systems of a hyperthermophilic archaeon. Infection with an environmental virus mixture resulted in the exclusive uptake of protospacers from a co-infecting putative conjugative plasmid. Spacer uptake occurred by two distinct mechanisms in only one of two CRISPR loci subfamilies present. In two loci, insertions, often multiple, occurred adjacent to the leader while in a third locus single spacers were incorporated throughout the array. Protospacer DNAs were excised from the invading genetic element immediately after CCN motifs, on either strand, with the secondary cut apparently produced by a ruler mechanism. Over a 10-week period, there was a gradual decrease in the number of wild-type cells present in the culture but the virus and putative conjugative plasmid were still propagating. The results underline the complex dynamics of CRISPR-based immune systems within a population infected with genetic elements. PMID:22834906

  8. Evidence for different pyoverdine-mediated iron uptake systems among Pseudomonas aeruginosa strains.

    PubMed Central

    Cornelis, P; Hohnadel, D; Meyer, J M

    1989-01-01

    Fourteen strains of Pseudomonas aeruginosa (P. aeruginosa ATCC 15692, P. aeruginosa ATCC 27853, and 12 clinical isolates) were checked for the production of pyoverdine and for pyoverdine-mediated iron uptake. Under iron restriction, two isolates produced undetectable amounts of pyoverdine, but all the other strains produced a compound with physicochemical properties identical or close to those of the pyoverdine of P. aeruginosa ATCC 15692 (strain PAO1). The pyoverdines were purified and tested for their growth-promoting activity and for their ability to facilitate 59Fe uptake in homologous experiments involving each pyoverdine and its producing strain, as well as in heterologous systems involving all the other strains. The results of both types of experiments suggested the existence of three specificity groups. This was confirmed by analysis of the amino acid composition of the pyoverdines, which differed for each group. A partially purified polyclonal antiserum raised against a major 80-kilodalton (kDa) iron-regulated outer membrane protein (IROMP) of P. aeruginosa PAO1 recognized the 80-kDa IROMPs from P. aeruginosa PAO1 and the clinical isolates belonging to the same group, whereas the IROMPs from the strains belonging to the two other groups were not detected. A second antiserum raised against the P. aeruginosa ATCC 27853 80-kDa IROMP gave similar results by reacting specifically with the 80-kDa IROMP from the strains belonging to this group. Thus, together with the already known pyoverdine from P. aeruginosa PAO1, two new types of pyoverdines produced by strains belonging to this species were characterized. Images PMID:2509364

  9. Characterization of ursodeoxycholic and norursodeoxycholic acid as substrates of the hepatic uptake transporters OATP1B1, OATP1B3, OATP2B1 and NTCP.

    PubMed

    König, Jörg; Klatt, Sabine; Dilger, Karin; Fromm, Martin F

    2012-08-01

    Ursodeoxycholic acid (UDCA) is the only approved treatment for primary biliary cirrhosis, and norursodeoxycholic acid (norUDCA) is currently tested in clinical trials for future treatment of primary sclerosing cholangitis because of beneficial effects in cholestatic Mdr2 knock-out mice. Uptake of UDCA and norUDCA into hepatocytes is believed to be a prerequisite for subsequent metabolism and therapeutic action. However, the molecular determinants of hepatocellular uptake of UDCA and norUDCA are poorly understood. We therefore investigated whether UDCA and norUDCA are substrates of the hepatic uptake transporters OATP1B1, OATP1B3, OATP2B1 and Na(+) -taurocholate co-transporting polypeptide (NTCP), which are localized in the basolateral membrane of hepatocytes. Uptake of [(3) H]UDCA and [(14) C]norUDCA into Human embryonic kidney (HEK) cells stably expressing OATP1B1, OATP1B3, OATP2B1 or NTCP was investigated and compared with uptake into vector control cells. Uptake ratios were calculated by dividing uptake into transporter-transfected cells by uptake into respective control cells. Uptake ratios of OATP1B1-, OATP1B3- and OATP2B1-mediated UDCA and norUDCA uptake were at maximum 1.23 and 1.49, respectively. Uptake of UDCA was significantly higher into HEK-NTCP cells only at the lowest tested concentration (1 μM, p < 0.001) compared with the control cells with an uptake ratio of 1.34-fold. NorUDCA was not significantly transported by NTCP. The low uptake rates suggest that OATP1B1, OATP1B3, OATP2B1 and NTCP are not relevant for hepatocellular uptake and effects of UDCA and norUDCA in human beings.

  10. Uptake measurements of acetic acid on ice and nitric acid-doped thin ice films over upper troposphere/lower stratosphere temperatures.

    PubMed

    Romanias, Manolis N; Zogka, Antonia G; Papadimitriou, Vassileios C; Papagiannakopoulos, Panos

    2012-03-01

    The adsorption of gaseous acetic acid (CH(3)C(O)OH) on thin ice films and on ice doped with nitric acid (1.96 and 7.69 wt %) was investigated over upper troposphere and lower stratosphere (UT/LS) temperatures (198-208 K), and at low gas concentrations. Experiments were performed in a Knudsen flow reactor coupled to a quadrupole mass spectrometer. The initial uptake coefficients, γ(0), on thin ice films or HNO(3)-doped ice films were measured at low surface coverage. In all cases, γ(0) showed an inverse temperature dependence, and for pure thin ice films, it was given by the expression γ(0)(T) = (4.73 ± 1.13) × 10(-17) exp[(6496 ± 1798)/T]; the quoted errors are the 2σ precision of the linear fit, and the estimated systematic uncertainties are included in the pre-exponential factor. The inverse temperature dependence suggests that the adsorption process occurs via the formation of an intermediate precursor state. Uptakes were well represented by the Langmuir adsorption model, and the saturation surface coverage, N(max), on pure thin ice films was (2.11 ± 0.16) × 10(14) molecules cm(-2), independent of temperature in the range 198-206 K. Light nitration (1.96 and 7.69 wt %) of ice films resulted in more efficient CH(3)C(O)OH uptakes and larger N(max) values that may be attributed to in-bulk diffusion or change in nature of the gas-ice surface interaction. Finally, it was estimated that the rate of adsorption of acetic acid on high-density cirrus clouds in the UT/LS is fast, and this is reflected in the short atmospheric lifetimes (2-8 min) of acetic acid; however, the extent of this uptake is minor resulting in at most a 5% removal of acetic acid in UT/LS cirrus clouds.

  11. Sulfate metabolism. I. Sulfate uptake and redistribution of acid rain sulfate by edible plants

    SciTech Connect

    Dallam, R.D.

    1987-03-23

    Sulfur is the major component of polluted air in industrialized societies. Atmospheric sulfur is converted to sulfuric acid through a series of chemical reactions which can eventually reenter many ecosystems. When edible plants are grown in soils containing varying amounts of sulfate, the roots take up and transport inorganic sulfate to the stems and leaves. The sulfate taken up by the roots and the amount transported to the stem and leaves was found to be a function of the concentration of sulfate in the soil. Inorganic sulfate taken up by a corn plant seedling can be rapidly converted to organic sulfate by the root system. Nine days after one of a pair of pea plants was inoculated with artificial acid rain sulfate (dilute H/sub 2//sup 35/SO/sub 4/) it was found that the sulfate was translocated not only in the inoculated plant, but also to the uninoculated pea plant in the same container. Also, when the leaves of a mature potato plant were inoculated with artificial acid rain sulfate it was found that the sulfate was translocated into the edible potatoes. Fractionation of the potatoes showed that most of the sulfate was water soluble of which 30% was inorganic sulfate and 70% was in the form of organic sulfur. One third of the non-water soluble translocated acid rain sulfate was equally divided between lipid and non-lipid organic sulfur of the potato. 9 references, 2 figures, 5 tables.

  12. Sulfate metabolism. I. Sulfate uptake and redistribution of acid rain sulfate by edible plants.

    PubMed

    Dallam, R D

    1987-03-23

    Sulfur is the major component of polluted air in industrialized societies. Atmospheric sulfur is converted to sulfuric acid through a series of chemical reactions which can eventually reenter many ecosystems. When edible plants are grown in soils containing varying amounts of sulfate, the roots take up and transport inorganic sulfate to the stems and leaves. The sulfate taken up by the roots and the amount transported to the stem and leaves was found to be a function of the concentration of sulfate in the soil. Inorganic sulfate taken up by a corn plant seedling can be rapidly converted to organic sulfate by the root system. Nine days after one of a pair of pea plants was inoculated with artificial acid rain sulfate (dilute H2 35SO4) it was found that the sulfate was translocated not only in the inoculated plant, but also to the uninoculated pea plant in the same container. Also, when the leaves of a mature potato plant were inoculated with artificial acid rain sulfate it was found that the sulfate was translocated into the edible potatoes. Fractionation of the potatoes showed that most of the sulfate was water soluble of which 30% was inorganic sulfate and 70% was in the form of organic sulfur. One third of the non-water soluble translocated acid rain sulfate was equally divided between lipid and non-lipid organic sulfur of the potato.

  13. Diastereomeric mixture of calophyllic acid and isocalophyllic acid stimulates glucose uptake in skeletal muscle cells: involvement of PI-3-kinase- and ERK1/2-dependent pathways.

    PubMed

    Prasad, Janki; Maurya, Chandan Kumar; Pandey, Jyotsana; Jaiswal, Natasha; Madhur, Gaurav; Srivastava, Arvind Kumar; Narender, Tadigoppula; Tamrakar, Akhilesh Kumar

    2013-05-01

    The diastereomeric mixture of calophyllic acid and isocalophyllic acid (F015) isolated from the leaves of Calophyllum inophyllum was investigated for the metabolic effect on glucose transport in skeletal muscle cells. In L6 myotubes, F015 dose-dependently stimulated glucose uptake by increasing translocation of glucose transporter4 (GLUT4) to plasma membrane without affecting their gene expression. The effects on glucose uptake were additive to insulin. Inhibitors analyses revealed that F015-induced glucose uptake was dependent on the activation of phosphatidylinositol-3-kinase (PI-3-K) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), while independent to the activation of 5'AMP-activated kinase (AMPK). F015 significantly increased the phosphorylation of AKT, AS160 and ERK1/2, account for the augmented glucose transport capacity in L6 myotubes. Furthermore, F015 improved glucose tolerance and enhanced insulin sensitivity in skeletal muscle of dexamethasone-induced insulin resistant mice. Our findings demonstrate that F015 activates glucose uptake in skeletal muscle cells through PI-3-K- and EKR1/2-dependent mechanisms and can be a potential lead for the management of diabetes and obesity.

  14. Conformationally-restricted amino acid analogues bearing a distal sulfonic acid show selective inhibition of system x(c)(-) over the vesicular glutamate transporter.

    PubMed

    Etoga, Jean-Louis G; Ahmed, S Kaleem; Patel, Sarjubhai; Bridges, Richard J; Thompson, Charles M

    2010-04-15

    A panel of amino acid analogs and conformationally-restricted amino acids bearing a sulfonic acid were synthesized and tested for their ability to preferentially inhibit the obligate cysteine-glutamate transporter system x(c)(-) versus the vesicular glutamate transporter (VGLUT). Several promising candidate molecules were identified: R/S-4-[4'-carboxyphenyl]-phenylglycine, a biphenyl substituted analog of 4-carboxyphenylglycine and 2-thiopheneglycine-5-sulfonic acid both of which reduced glutamate uptake at system x(c)(-) by 70-75% while having modest to no effect on glutamate uptake at VGLUT.

  15. Root-uptake of (14)C derived from acetic acid and (14)C transfer to rice edible parts.

    PubMed

    Ogiyama, Shinichi; Suzuki, Hiroyuki; Inubushi, Kazuyuki; Takeda, Hiroshi; Uchida, Shigeo

    2010-02-01

    Three types of culture experiments using paddy rice (Oryza sativa L.) were performed to examine root-uptake of (14)C in the form of acetic acid: double pot experiment (hydroponics), wet culture experiment (submerged sand medium), and chamber experiment (hydroponics and submerged sand medium). The (14)C radioactivity in the plant, mediums, and atmospheric carbon dioxide ((14)CO(2)) in the chamber were determined, and the distribution of (14)C in the plant was visualized using autoradiography. In the double pot experiment, the shoot of the plant and the lower root which was soaked in the culture solution had (14)C radioactivity, but the upper root which did not have contact with the solution had none. There were also (14)C radioactivity in the grains and roots in the wet culture experiment. Results of the chamber experiment showed that (14)CO(2) gas was released from the culture solution in both types of cultures. Results indicated that the (14)C-acetic acid absorbed by rice plant through its root would be very small. Most of the (14)C-acetic acid was transformed into gaseous forms either in the culture solution or rhizosphere. A relatively longer time would be needed to assimilate (14)C derived from acetic acid to grain parts after it was once absorbed by the shoot through the root. Availability of (14)C for the plant in sand culture was considered to be decreased compared with that for the plant in the hydroponics experiment. It was suggested that rice plant absorbed and assimilated (14)C through the plant roots not because of uptake of (14)C-acetic acid but because of uptake of (14)C in gaseous forms such as (14)CO(2). PMID:19962904

  16. Tartaric Acid-based Amphiphilic Macromolecules with Ether Linkages Exhibit Enhanced Repression of Oxidized Low Density Lipoprotein Uptake

    PubMed Central

    Abdelhamid, Dalia; Zhang, Yingue; Lewis, Daniel R.; Moghe, Prabhas V.; Welsh, William J.; Uhrich, Kathryn E.

    2015-01-01

    Cardiovascular disease initiates with the atherogenic cascade of scavenger receptor- (SR-) mediated oxidized low-density lipoprotein (oxLDL) uptake. Resulting foam cell formation leads to lipid-rich lesions within arteries. We designed amphiphilic macromolecules (AMs) to inhibit these processes by competitively blocking oxLDL uptake via SRs, potentially arresting atherosclerotic development. In this study, we investigated the impact of replacing ester linkages with ether linkages in the AM hydrophobic domain. We hypothesized that ether linkages would impart flexibility for orientation to improve binding to SR binding pockets, enhancing anti-atherogenic activity. A series of tartaric acid-based AMs with varying hydrophobic chain lengths and conjugation chemistries were synthesized, characterized, and evaluated for bioactivity. 3-D conformations of AMs in aqueous conditions may have significant effects on anti-atherogenic potency and were simulated by molecular modeling. Notably, ether-linked AMs exhibited significantly higher levels of inhibition of oxLDL uptake than their corresponding ester analogues, indicating a dominant effect of linkage flexibility on pharmacological activity. The degradation stability was also enhanced for ether-linked AMs. These studies further suggested that alkyl chain length (i.e., relative hydrophobicity), conformation (i.e., orientation), and chemical stability play a critical role in modulating oxLDL uptake, and guide the design of innovative cardiovascular therapies. PMID:25890704

  17. A proton transfer reaction mass spectrometry based system for determining plant uptake of volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Tani, Akira; Kato, Shungo; Kajii, Yoshizumi; Wilkinson, Michael; Owen, Sue; Hewitt, Nick

    In order to evaluate the contribution that higher plants make to the removal of volatile organic compounds from the atmosphere, a measurement system consisting of a proton transfer reaction mass spectrometer (PTR-MS), CO 2 analyzer, diffusion devise and leaf enclosure was established. The uptake of VOCs by Golden Pothos ( Epipremnum aureum) was investigated. The overall relative error associated with measurements made using this system was <2.2% when a Golden Pothos leaf was exposed to 75-750 ppbv of methyl isobutyl ketone (MIBK). Even at the lowest MIBK concentration, more than 2.2% of the inflowing VOC was lost to the leaf, representing a detectable and positive MIBK uptake rate by the plant. The results of the investigation were compared with a measurement system based on gas chromatography analysis and it was shown that the use of a PTR-MS based system can significantly increase the certainties in determining the rate of VOC uptake by plants.

  18. Acetic acid inhibits nutrient uptake in Saccharomyces cerevisiae: auxotrophy confounds the use of yeast deletion libraries for strain improvement.

    PubMed

    Ding, Jun; Bierma, Jan; Smith, Mark R; Poliner, Eric; Wolfe, Carole; Hadduck, Alex N; Zara, Severino; Jirikovic, Mallori; van Zee, Kari; Penner, Michael H; Patton-Vogt, Jana; Bakalinsky, Alan T

    2013-08-01

    Acetic acid inhibition of yeast fermentation has a negative impact in several industrial processes. As an initial step in the construction of a Saccharomyces cerevisiae strain with increased tolerance for acetic acid, mutations conferring resistance were identified by screening a library of deletion mutants in a multiply auxotrophic genetic background. Of the 23 identified mutations, 11 were then introduced into a prototrophic laboratory strain for further evaluation. Because none of the 11 mutations was found to increase resistance in the prototrophic strain, potential interference by the auxotrophic mutations themselves was investigated. Mutants carrying single auxotrophic mutations were constructed and found to be more sensitive to growth inhibition by acetic acid than an otherwise isogenic prototrophic strain. At a concentration of 80 mM acetic acid at pH 4.8, the initial uptake of uracil, leucine, lysine, histidine, tryptophan, phosphate, and glucose was lower in the prototrophic strain than in a non-acetic acid-treated control. These findings are consistent with two mechanisms by which nutrient uptake may be inhibited. Intracellular adenosine triphosphate (ATP) levels were severely decreased upon acetic acid treatment, which likely slowed ATP-dependent proton symport, the major form of transport in yeast for nutrients other than glucose. In addition, the expression of genes encoding some nutrient transporters was repressed by acetic acid, including HXT1 and HXT3 that encode glucose transporters that operate by facilitated diffusion. These results illustrate how commonly used genetic markers in yeast deletion libraries complicate the effort to isolate strains with increased acetic acid resistance.

  19. Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection.

    PubMed

    Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra; Visca, Paolo

    2016-08-01

    Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe(3+) uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe(2+) acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe(3+) transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities. PMID:27271740

  20. Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection.

    PubMed

    Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra; Visca, Paolo

    2016-08-01

    Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe(3+) uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe(2+) acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe(3+) transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities.

  1. Capsaicin, nonivamide and trans-pellitorine decrease free fatty acid uptake without TRPV1 activation and increase acetyl-coenzyme A synthetase activity in Caco-2 cells.

    PubMed

    Rohm, Barbara; Riedel, Annett; Ley, Jakob P; Widder, Sabine; Krammer, Gerhard E; Somoza, Veronika

    2015-01-01

    Red pepper and its major pungent component, capsaicin, have been associated with hypolipidemic effects in rats, although mechanistic studies on the effects of capsaicin and/or structurally related compounds on lipid metabolism are scarce. In this work, the effects of capsaicin and its structural analog nonivamide, the aliphatic alkamide trans-pellitorine and vanillin as the basic structural element of all vanilloids on the mechanisms of intestinal fatty acid uptake in differentiated intestinal Caco-2 cells were studied. Capsaicin and nonivamide were found to reduce fatty acid uptake, with IC₅₀ values of 0.49 μM and 1.08 μM, respectively. trans-Pellitorine was shown to reduce fatty acid uptake by 14.0±2.14% at 100 μM, whereas vanillin was not effective, indicating a pivotal role of the alkyl chain with the acid amide group in fatty acid uptake by Caco-2 cells. This effect was associated neither with the activation of the transient receptor potential cation channel subfamily V member 1 (TRPV1) or the epithelial sodium channel (ENaC) nor with effects on paracellular transport or glucose uptake. However, acetyl-coenzyme A synthetase activity increased (p<0.05) in the presence of 10 μM capsaicin, nonivamide or trans-pellitorine, pointing to an increased fatty acid biosynthesis that might counteract the decreased fatty acid uptake.

  2. Increased Hepatic Fatty Acids Uptake and Oxidation by LRPPRC-Driven Oxidative Phosphorylation Reduces Blood Lipid Levels.

    PubMed

    Lei, Shi; Sun, Run-Zhu; Wang, Di; Gong, Mei-Zhen; Su, Xiang-Ping; Yi, Fei; Peng, Zheng-Wu

    2016-01-01

    Hyperlipidemia is one of the major risk factors of atherosclerosis and other cardiovascular diseases. This study aimed to investigate the impact of leucine rich pentatricopeptide repeat containing protein (LRPPRC)-driven hepatic oxidative phoshorylation on blood lipid levels. The hepatic LRPPRC level was modulated by liver-specific transgenic or adeno-associated virus 8 carried shRNA targeting Lrpprc (aav-shLrpprc). Mice were fed with a high fat diet to induce obesity. Gene expression was analyzed by quantitative real-time PCR and / or western blot. The hepatic ATP level, hepatic and serum lipids contents, and mitochondria oxidative phosphorylation (OxPhos) complex activities were measured using specific assay kits. The uptake and oxidation of fatty acid by hepatocytes were assessed using (14)C-palmitate. LRPPRC regulated the expression of genes encoded by mitochondrial genome but not those by nuclear genome involved in mitochondria biogenesis, OxPhos, and lipid metabolism. Increased OxPhos in liver mediated by LRPPRC resulted in the increase of hepatic ATP level. Lrpprc promoted palmitate uptake and oxidation by hypatocytes. The hepatic and serum triglyceride and total cholesterol levels were inversely associated with the hepatic LRPPRC level. These data demonstrated that LRPPRC-driven hepatic OxPhos could promote fatty acids uptake and oxidation by hepatocytes and reduce both hepatic and circulating triglyceride and cholesterol levels. PMID:27462273

  3. Increased Hepatic Fatty Acids Uptake and Oxidation by LRPPRC-Driven Oxidative Phosphorylation Reduces Blood Lipid Levels

    PubMed Central

    Lei, Shi; Sun, Run-zhu; Wang, Di; Gong, Mei-zhen; Su, Xiang-ping; Yi, Fei; Peng, Zheng-wu

    2016-01-01

    Hyperlipidemia is one of the major risk factors of atherosclerosis and other cardiovascular diseases. This study aimed to investigate the impact of leucine rich pentatricopeptide repeat containing protein (LRPPRC)-driven hepatic oxidative phoshorylation on blood lipid levels. The hepatic LRPPRC level was modulated by liver-specific transgenic or adeno-associated virus 8 carried shRNA targeting Lrpprc (aav-shLrpprc). Mice were fed with a high fat diet to induce obesity. Gene expression was analyzed by quantitative real-time PCR and / or western blot. The hepatic ATP level, hepatic and serum lipids contents, and mitochondria oxidative phosphorylation (OxPhos) complex activities were measured using specific assay kits. The uptake and oxidation of fatty acid by hepatocytes were assessed using 14C-palmitate. LRPPRC regulated the expression of genes encoded by mitochondrial genome but not those by nuclear genome involved in mitochondria biogenesis, OxPhos, and lipid metabolism. Increased OxPhos in liver mediated by LRPPRC resulted in the increase of hepatic ATP level. Lrpprc promoted palmitate uptake and oxidation by hypatocytes. The hepatic and serum triglyceride and total cholesterol levels were inversely associated with the hepatic LRPPRC level. These data demonstrated that LRPPRC-driven hepatic OxPhos could promote fatty acids uptake and oxidation by hepatocytes and reduce both hepatic and circulating triglyceride and cholesterol levels. PMID:27462273

  4. Tissue specific uptake and elimination of perfluoroalkyl acids (PFAAs) in adult rainbow trout (Oncorhynchus mykiss) after dietary exposure.

    PubMed

    Falk, Sandy; Failing, Klaus; Georgii, Sebastian; Brunn, Hubertus; Stahl, Thorsten

    2015-06-01

    Tissue specific uptake and elimination of perfluoroalkyl acids (PFAAs) were studied in rainbow trout (Oncorhynchus mykiss). Adult trout were exposed to perfluorobutane sulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) via food over a time period of 28d. In the following 28-d depuration period the fish were fed PFAA-free food. At defined sampling times four animals were removed from the experimental tank, euthanized and dissected. Muscle, liver, kidneys, gills, blood, skin and carcass were examined individually. At the end of the accumulation phase between 0.63% (PFOA) and 15.5% (PFOS) of the absolute, applied quantity of PFAAs was recovered in the whole fish. The main target organ was the liver with recovery rates between 0.11% (PFBS) and 4.01% (PFOS) of the total amount of ingested PFAAs. Perfluoroalkyl sulfonic acids were taken up more readily and had longer estimated elimination half-lives than perfluoroalkyl carboxylic acids of the same chain length. The longest estimated elimination half-lives were found to be for PFOS between 8.4d in muscle tissue and 20.4d in the liver and for PFNA between 8.2d in the blood and 11.6d in the liver.

  5. Organosulfate formation during the uptake of pinonaldehyde on acidic sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, John; Li, Shao-Meng

    2006-07-01

    Organosulfates are observed in studies of pinonaldehyde reactions with acidic sulfate aerosols using aerosol mass spectrometry, during which a significant fraction of the pinonaldehyde reaction products were found to consist of organosulfate compounds that account for 6-51% of the initial SO4= mass. Resultant aerosol mass spectra were consistent with proposed sulfate ester mechanisms, which likely form stable products. The existence of organosulfates was also confirmed in studies of the reaction system in bulk solution. The formation of organosulfates suggests that conventional inorganic SO4= chemical analysis may underestimate total SO4= mass in ambient aerosols.

  6. An Inexpensive Electrode and Cell for Measurement of Oxygen Uptake in Chemical and Biochemical Systems.

    ERIC Educational Resources Information Center

    Brunet, Juan E.; And Others

    1983-01-01

    The continuous measurement of oxygen consumption in an enzymatic reaction is a frequent experimental fact and extremely important in the enzymatic activity of oxygenase. An electrochemical system, based on a polarographic method, has been developed to monitor the oxygen uptake. The system developed and electrode used are described. (JN)

  7. Design, synthesis and SAR studies of GABA uptake inhibitors derived from 2-substituted pyrrolidine-2-yl-acetic acids.

    PubMed

    Steffan, Tobias; Renukappa-Gutke, Thejavathi; Höfner, Georg; Wanner, Klaus T

    2015-03-15

    In this paper, we disclose the design and synthesis of a series of 2-substituted pyrrolidine-2-yl-acetic acid as core structures and the N-arylalkyl derivatives thereof as potential GABA transport inhibitors. The 2-position in the side chain of pyrrolidine-2-yl-acetic acid derivatives was substituted with alkyl, hydroxy and amino groups to modulate the activity and selectivity to mGAT1 and mGAT4 proteins. SAR studies of the compounds performed for the four mouse GABA transporter proteins (mGAT1-mGAT4) implied significant potencies and subtype selectivities for 2-hydroxy-2-pyrrolidine-2-yl-acetic acid derivatives. The racemate rac-(u)-13c exhibited the highest potency (pIC50 5.67) at and selectivity for mGAT1 in GABA uptake assays. In fact, the potency of rac-(u)-13c at hGAT-1 (pIC50 6.14) was even higher than its potency at mGAT1. These uptake results for rac-(u)-13c are in line with the binding affinities to the aforesaid proteins mGAT1 (pKi 6.99) and hGAT-1 (pKi 7.18) determined by MS Binding Assay based on NO711 as marker quantified by LC-ESI-MS-MS analysis. Interestingly, the 2-hydroxy-2-pyrrolidine-2-yl-acetic acid rac-(u)-13d containing 2-{[tris(4-methoxyphenyl)]methoxy} ethyl group at the nitrogen atom of the pyrrolidine ring showed high potency at mGAT4 and a comparatively better selectivity for this protein (>15 against mGAT3) than the well known mGAT4 uptake inhibitor (S)-SNAP-5114.

  8. Uptake and metabolism of the short-chain fatty acid butyrate, a critical review of the literature.

    PubMed

    Astbury, Stuart M; Corfe, Bernard M

    2012-07-01

    Butyrate is a short-chain fatty acid (SCFA) formed by bacterial fermentation of fibre in the colon, and serves as an energy source for colonocytes. The action of butyrate as a histone deacetylase inhibitor (HDACi) has led to a number of clinical trials testing its effectiveness as a potential treatment for cancer. The biology of butyrate transport is therefore relevant to both its physiological and pharmacological benefits. This review of the literature was carried out to assess the evidence for both the uptake and metabolism of butyrate, in an attempt to determine possible mechanism (s) by which butyrate can act as an HDACi. It is noted that although uptake and metabolism are well characterised, there are still significant gaps in the knowledgebase around the intracellular handing of butyrate, where assumptions or dated evidence are relied upon.

  9. Computer-aided rational design of the phosphotransferase system for enhanced glucose uptake in Escherichia coli.

    PubMed

    Nishio, Yousuke; Usuda, Yoshihiro; Matsui, Kazuhiko; Kurata, Hiroyuki

    2008-01-01

    The phosphotransferase system (PTS) is the sugar transportation machinery that is widely distributed in prokaryotes and is critical for enhanced production of useful metabolites. To increase the glucose uptake rate, we propose a rational strategy for designing the molecular architecture of the Escherichia coli glucose PTS by using a computer-aided design (CAD) system and verified the simulated results with biological experiments. CAD supports construction of a biochemical map, mathematical modeling, simulation, and system analysis. Assuming that the PTS aims at controlling the glucose uptake rate, the PTS was decomposed into hierarchical modules, functional and flux modules, and the effect of changes in gene expression on the glucose uptake rate was simulated to make a rational strategy of how the gene regulatory network is engineered. Such design and analysis predicted that the mlc knockout mutant with ptsI gene overexpression would greatly increase the specific glucose uptake rate. By using biological experiments, we validated the prediction and the presented strategy, thereby enhancing the specific glucose uptake rate.

  10. Thyroid hormone effects on whole-body energy homeostasis and tissue-specific fatty acid uptake in vivo.

    PubMed

    Klieverik, Lars P; Coomans, Claudia P; Endert, Erik; Sauerwein, Hans P; Havekes, Louis M; Voshol, Peter J; Rensen, Patrick C N; Romijn, Johannes A; Kalsbeek, Andries; Fliers, Eric

    2009-12-01

    The effects of thyroid hormone (TH) status on energy metabolism and tissue-specific substrate supply in vivo are incompletely understood. To study the effects of TH status on energy metabolism and tissue-specific fatty acid (FA) fluxes, we used metabolic cages as well as (14)C-labeled FA and (3)H-labeled triglyceride (TG) infusion in rats treated with methimazole and either 0 (hypothyroidism), 1.5 (euthyroidism), or 16.0 (thyrotoxicosis) microg per 100 g/d T(4) for 11 d. Thyrotoxicosis increased total energy expenditure by 38% (P = 0.02), resting energy expenditure by 61% (P = 0.002), and food intake by 18% (P = 0.004). Hypothyroidism tended to decrease total energy expenditure (10%; P = 0.064) and resting energy expenditure (12%; P = 0.025) but did not affect food intake. TH status did not affect spontaneous physical activity. Thyrotoxicosis increased fat oxidation (P = 0.006), whereas hypothyroidism decreased glucose oxidation (P = 0.035). Plasma FA concentration was increased in thyrotoxic but not hypothyroid rats. Thyrotoxicosis increased albumin-bound FA uptake in muscle and white adipose tissue (WAT), whereas hypothyroidism had no effect in any tissue studied, suggesting mass-driven albumin-bound FA uptake. During thyrotoxicosis, TG-derived FA uptake was increased in muscle and heart, unaffected in WAT, and decreased in brown adipose tissue. Conversely, during hypothyroidism TG-derived FA uptake was increased in WAT in association with increased lipoprotein lipase activity but unaffected in oxidative tissues and decreased in liver. In conclusion, TH status determines energy expenditure independently of spontaneous physical activity. The changes in whole-body lipid metabolism are accompanied by tissue-specific changes in TG-derived FA uptake in accordance with hyper- and hypometabolic states induced by thyrotoxicosis and hypothyroidism, respectively.

  11. K+ uptake in plant roots. The systems involved, their regulation and parallels in other organisms.

    PubMed

    Nieves-Cordones, Manuel; Alemán, Fernando; Martínez, Vicente; Rubio, Francisco

    2014-05-15

    Potassium (K(+)) is an essential macronutrient for plants. It is taken into the plant by the transport systems present in the plasma membranes of root epidermal and cortical cells. The identity of these systems and their regulation is beginning to be understood and the systems of K(+) transport in the model species Arabidopsis thaliana remain far better characterized than in any other plant species. Roots can activate different K(+) uptake systems to adapt to their environment, important to a sessile organism that needs to cope with a highly variable environment. The mechanisms of K(+) acquisition in the model species A. thaliana are the best characterized at the molecular level so far. According to the current model, non-selective channels are probably the main pathways for K(+) uptake at high concentrations (>10mM), while at intermediate concentrations (1mM), the inward rectifying channel AKT1 dominates K(+) uptake. Under lower concentrations of external K(+) (100μM), AKT1 channels, together with the high-affinity K(+) uptake system HAK5 contribute to K(+) acquisition, and at extremely low concentrations (<10μM) the only system capable of taking up K(+) is HAK5. Depending on the species the high-affinity system has been named HAK5 or HAK1, but in all cases it fulfills the same functions. The activation of these systems as a function of the K(+) availability is achieved by different mechanisms that include phosphorylation of AKT1 or induction of HAK5 transcription. Some of the characteristics of the systems for root K(+) uptake are shared by other organisms, whilst others are specific to plants. This indicates that some crucial properties of the ancestral of K(+) transport systems have been conserved through evolution while others have diverged among different kingdoms.

  12. Folic acid and prevention of neural tube defects in 2000 improved awareness--low peri-conceptional uptake.

    PubMed

    Oleary, M; Donnell, R M; Johnson, H

    2001-06-01

    Eight years have passed since recommendations were made by the Irish Department of Health on the importance of folic acid in the prevention of neural tube defects (NTD). There is currently no mandatory fortification of foodstuffs with folic acid in Ireland, with reliance placed on campaigns promoting increased dietary folate intake and supplements. We assessed knowledge and use of folic acid among 300 women attending ante-natal clinics in Dublin maternity hospitals in the year 2000 using an interviewer administered questionnaire. Qualitative information was obtained through means of a focus group. Ninety two percent of respondents had heard of folic acid and 67% knew it could prevent NTD. Thirty per cent were advised to take it peri-conceptionally but overall only 18% did so; 39% of women had planned their pregnancy. The focus group indicated that folic acid was not 'visible' enough and that fortification of food was more realistic. This study shows that improved folic acid awareness has not been accompanied by corresponding peri-conceptional uptake in 2000. Folic acid promotional campaigns should be continuous and targeted. Mandatory food fortification should be strongly considered.

  13. Adipocyte Accumulation of Long-Chain Fatty Acids in Obesity is Multifactorial, Resulting from Increased Fatty Acid Uptake and Decreased Activity of Genes Involved in Fat Utilization

    PubMed Central

    Walewski, José L.; Ge, Fengxia; Gagner, Michel; Inabnet, William B.; Pomp, Alfons; Branch, Andrea D.

    2010-01-01

    Background The obesity epidemic causes significant morbidity and mortality. Knowledge of cellular function and gene expression in obese adipose tissue will yield insights into obesity pathogenesis and suggest therapeutic targets. The aim of this work is to study the processes determining fat accumulation in adipose tissue from obese patients. Methods Omental fat was collected from two cohorts of obese bariatric surgery patients and sex-matched normal-weight donors. Isolated adipocytes were compared for cell size, volume, and long-chain fatty acid (LCFA) uptake. Omental fat RNAs were screened by 10K microarray (cohort 1: three obese, three normal) or Whole Genome microarray (cohort 2: seven obese, four normal). Statistical differences in gene and pathway expression were identified in cohort 1 using the GeneSifter Software (Geospiza) with key results confirmed in cohort 2 samples by microarray, quantitative real-time polymerase chain reaction, and pathway analysis. Results Obese omental adipocytes had increased surface area, volume, and Vmax for saturable LCFA uptake. Dodecenoyl-coenzyme A delta isomerase, central to LCFA metabolism, was approximately 1.6-fold underexpressed in obese fat in cohorts 1 and 2. Additionally, the Kyoto Encyclopedia of Genes and Genomics pathway analysis identified oxidative phosphorylation and fatty acid metabolism pathways as having coordinate, nonrandom down-regulation of gene expression in both cohorts. Conclusions In obese omental fat, saturable adipocyte LCFA uptake was greater than in controls, and expression of key genes involved in lipolysis, β-oxidation, and metabolism of fatty acids was reduced. Thus, both increased uptake and reduced metabolism of LCFAs contribute to the accumulation of LCFAs in obese adipocytes. PMID:19866242

  14. Biological nitrogen removal with enhanced phosphate uptake in a sequencing batch reactor using single sludge system.

    PubMed

    Lee, D S; Jeon, C O; Park, J M

    2001-11-01

    Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor ((AO)2 SBR). Significant amounts of phosphorus-accumulation organisms (PAOs) capable of denitrification could be accumulated in a single sludge system coexisting with nitrifiers. The ratio of the anoxic phosphate uptake to the aerobic phosphate uptake capacity was increased from 11% to 64% by introducing an anoxic phase in an anaerobic aerobic SBR. The (AO)2 SBR system showed stable phosphorus and nitrogen removal performance. Average removal efficiencies of TOC, total nitrogen, and phosphorus were 92%, 88%, and 100%, respectively. It was found that nitrite (up to 10 mg NO2(-)-N/l) was not detrimental to the anoxic phosphate uptake and could serve as an electron acceptor like nitrate. In fact, the phosphate uptake rate was even faster in the presence of nitrite as an electron acceptor compared to the presence of nitrate. It was found that on-line sensor values of pH, ORP, and DO were somehow related with the dynamic behaviours of nutrient concentrations (NH4+, NO3-, and PO4(3-)) in the SBR. These on-line sensor values were used as real-time control parameters to adjust the duration of each operational phase in the (AO)2 SBR. The real-time controlled SBR exhibited better performance in the removal of phosphorus and nitrogen than the SBR with fixed-time operation. PMID:12230180

  15. Nucleic acid based logical systems.

    PubMed

    Han, Da; Kang, Huaizhi; Zhang, Tao; Wu, Cuichen; Zhou, Cuisong; You, Mingxu; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

    2014-05-12

    Researchers increasingly visualize a significant role for artificial biochemical logical systems in biological engineering, much like digital logic circuits in electrical engineering. Those logical systems could be utilized as a type of servomechanism to control nanodevices in vitro, monitor chemical reactions in situ, or regulate gene expression in vivo. Nucleic acids (NA), as carriers of genetic information with well-regulated and predictable structures, are promising materials for the design and engineering of biochemical circuits. A number of logical devices based on nucleic acids (NA) have been designed to handle various processes for technological or biotechnological purposes. This article focuses on the most recent and important developments in NA-based logical devices and their evolution from in vitro, through cellular, even towards in vivo biological applications.

  16. Intracellular Uptake and Trafficking of Difluoroboron Dibenzoylmethane-Poly(lactic acid) Nanoparticles in HeLa Cells

    PubMed Central

    Contreras, Janette; Xie, Jiansong; Chen, Yin Jie; Pei, Hua; Zhang, Guoqing; Fraser, Cassandra L.; Hamm-Alvarez, Sarah F.

    2010-01-01

    In this study, nanoparticles based on difluoroboron dibenzoylmethane-poly(lactic acid) (BF2dbmPLA) are prepared. Polylactic acid or polylactide is a commonly used degradable polymer, while the boron dye possesses a large extinction coefficient, high emission quantum yield, 2-photon absorption, and sensitivity to the surrounding environment. BF2dbmPLA exhibits molecular weight-dependent emission properties, and can be formulated as stable nanoparticles, suggesting that its unique optical properties may be useful in multiple contexts for probing intracellular environments. Here we show that BF2dbmPLA nanoparticles are internalized into cultured HeLa cells by endocytosis, and that within the cellular milieu they retain their fluorescence properties. BF2dbmPLA nanoparticles are photostable, resisting laser-induced photobleaching under conditions that destroy the fluorescence of a common photostable probe, LysoTracker™ blue. Their endocytosis is also lipid raft-dependent, as evidenced by their significant co-localization with cholera toxin B subunit in membrane compartments after uptake, and their sensitivity of uptake to methyl-β-cyclodextrin. Additionally, BF2dbmPLA nanoparticle endocytosis utilizes microtubules and actin filaments. Internalized BF2dbmPLA nanoparticles do not accumulate in acidic late endosomes and lysosomes, but within a perinuclear non-lysosomal compartment. These findings demonstrate the feasibility of using novel BF2dbmPLA nanoparticles exhibiting diverse emission properties for in situ, live cell imaging, and suggest that their endogenous uptake occurs through a lipid-raft dependent endocytosis mechanism. PMID:20420413

  17. Boric Acid Reclamation System (BARS)

    SciTech Connect

    Kniazewycz, B.G.; Markind, J.

    1986-03-01

    KLM Technologies' personnel have identified a Boric Acid Reclamation System (BARS) utilizing reverse osmosis and ultrafiltration to produce a recyclable grade of otherwise waste boric acid at PWRs, thus reducing a major source of low-level radwaste. The design of a prototype BARS as a compact volume reduction system was the result of KLM's Phase 1 Program, and based upon a preliminary feasibility program, which assessed the applicability of membrane technology to refurbish and recycle waste boric acid from floor and equipment drain streams. The analysis of the overall program indicated a substantial savings regarding off-site disposal costs. Today's economic scenario indicates that optimization of volume reduction operation procedures could significantly reduce waste management costs, especially where burial penalties have become more severe. As a reaction to the economic burden imposed by final disposal, many nuclear plants are currently modifying their design and operating philosophies concerning liquid radwaste processing systems to meet stricter environmental regulations, and to derive potential economic benefits by reducing the ever-increasing volumes of wastes that are produced. To effect these changes, innovative practices in waste management and more efficient processing technologies are being successfully implemented.

  18. Improving solubility, stability, and cellular uptake of resveratrol by nanoencapsulation with chitosan and γ-poly (glutamic acid).

    PubMed

    Jeon, Young Ok; Lee, Ji-Soo; Lee, Hyeon Gyu

    2016-11-01

    Resveratrol (RES), a polyphenolic compound found in grape skins, is a potent antioxidant with broad health benefits. However, its utilization in food has been limited by its poor water solubility, instability, and low bioavailability. The purpose of this study is to improve the solubility, stability, and cellular uptake of RES by nanoencapsulation using chitosan (CS) and γ-poly (glutamic acid) (γ-PGA). The size of nanoparticles significantly decreases with a decrease in the CS/γ-PGA ratio (p<0.05). The nanoparticle size with CS/γ-PGA ratio of 5 was 100-150nm. The entrapment efficiency and UV-light protection effect significantly increases (p<0.05), with an increase in the CS and γ-PGA concentration. The solubility of RES increases 3.2 and 4.2 times before and after lyophilization by nanoencapsulation, respectively. Compared with non-nanoencapsulated RES, the nanoencapsulated RES tends to maintain its solubility and antioxidant activity during storage. CS/γ-PGA nanoencapsulation was able to significantly enhance the transport of RES across a Caco-2 cell monolayer (p<0.05). The highest cellular uptake was found for nanoparticles prepared with 0.5mg/mL CS and 0.1mg/mL γ-PGA, which showed the highest solubility and antioxidant activity during storage. Therefore, CS/γ-PGA nanoencapsulation is found to be a potentially valuable technique for improving the solubility, stability, and cellular uptake of RES. PMID:27518454

  19. Foliar leaching and root uptake of Ca, Mg and K in relation to acid fog effects on Douglas Fir

    SciTech Connect

    Turner, D.P.; Tingey, D.T.

    1990-01-01

    The impact of acid fog on foliar leaching and root uptake of Ca, Mg, and K by Douglas-fir (Pseudotsuga menziesii) seedlings was examined. In a factorial experiment, 1-year old seedlings were grown in a solution culture at two levels of nutrient availability (low and moderate) and exposed twice a week (4 hr per event) for 12 weeks to fog at pH 5.6 or pH 3.1. Throughfall enrichment of Ca, Mg and K was determined from drip collectors at the base of each seedling and root uptake rates for trees under the moderate nutrient regime were evaluated by monitoring nutrient solution depletion. Throughfall enrichment was higher in the pH 3.1 fog than the pH 5.6 fog but much of the enrichment appeared to be wash off of precipitate from previous fogs. The amounts of nutrients coming off of the foliage with the low pH fog were small relative to the daily uptake rates. Foliar concentrations of K and Mg at the end of the exposures were lower under the low nutrient regime but were not affected by fog pH. Comparisons of wax weight and examinations of epicuticular wax by electron microscopy did not indicate a significant impact from exposure to the low pH fog.

  20. Docosahexaenoic acid enhances iron uptake by modulating iron transporters and accelerates apoptotic death in PC12 cells.

    PubMed

    Schonfeld, Eldi; Yasharel, Ilanit; Yavin, Ephraim; Brand, Annette

    2007-10-01

    The effect of docosahexaenoic acid (DHA; 22:6 n-3) on Fe(2+)-mediated and/or H(2)O(2)-mediated oxidative stress (OS) was investigated in a PC12 pheochromocytoma cell line in the presence or absence of 50 ng/ml nerve growth factor (NGF). DHA-supplemented cells showed enhanced Fe(2+)-induced cell damage as evident by increased lipid peroxides formation (10-fold) and reduced neutral red (NR) dye uptake in a NGF-independent fashion. DHA caused a nearly 10-fold increase in free iron uptake in NGF-treated cells and doubled iron uptake in nondifferentiated cells. DHA-enrichment induced an elevation in the transferrin receptor protein in the nondifferentiated cells whereas NGF-treatment led to a substantial increase in the ubiquitous divalent metal ion transporter 1 (DMT-1) as detected by mRNA levels using qRT-PCR. The mechanism of action of DHA to accelerate cell death may be associated with the externalization of amino-phosphoglycerides (PG) species of which, increased ethanolamine plasmalogen levels, may be essential for cell rescue as noted in NGF-treated PC12 cells. PMID:17551831

  1. Topical imiquimod yields systemic effects due to unintended oral uptake.

    PubMed

    Grine, Lynda; Steeland, Sophie; Van Ryckeghem, Sara; Ballegeer, Marlies; Lienenklaus, Stefan; Weiss, Siegfried; Sanders, Niek N; Vandenbroucke, Roosmarijn E; Libert, Claude

    2016-01-01

    Repetitive application of topical imiquimod is used as an experimental model for the induction of psoriasiform skin lesions in mice. The model is characterized by several inflammatory processes, including cytokine production both locally and systemically, cellular infiltration, and splenomegaly. To investigate the production of type I interferons in response to imiquimod-containing Aldara cream, IFNβ-luciferase reporter mice were imaged in vivo and ex vivo. Type I interferons were found to be produced in the skin, but also in the intestinal system caused by unintended ingestion of imiquimod by the mice. Through the use of Elizabethan collars to prevent ingestion, these effects, including psoriasiform lesions were nearly completely prevented. Our findings reveal that topical treatment with Aldara induces a psoriasiform skin inflammation, but that its mode of action depends on ingestion of the chemical, which leads to systemic responses and affects local inflammation. Therefore, potential ingestion of topical treatments during experimental procedures should be taken into account during assessment of cutaneous inflammatory parameters in skin disease models. PMID:26818707

  2. Influence of different acid and alkaline cleaning agents on the effects of irrigation of synthetic dairy factory effluent on soil quality, ryegrass growth and nutrient uptake.

    PubMed

    Liu, Y-Y; Haynes, R J

    2013-01-01

    The aim of this study was to examine the effects of replacement of phosphoric acid with nitric or acetic acid, and replacement of NaOH with KOH, as cleaning agents in dairy factories, on the effects that irrigation of dairy factory effluent (DFE) has on the soil-plant system. A 16-week greenhouse study was carried out in which the effects of addition of synthetic dairy factory effluent containing (a) milk residues alone or milk residues plus (b) H(3)PO(4)/NaOH, (c) H(3)PO(4)/HNO(3)/NaOH or (d) CH(3)COOH/KOH, on soil's chemical, physical and microbial properties and perennial ryegrass growth and nutrient uptake were investigated. The cumulative effect of DFE addition was to increase exchangeable Na, K, Ca, Mg, exchangeable sodium percentage, microbial biomass C and N and basal respiration in the soil. Dry matter yields of ryegrass were increased by additions of DFE other than that containing CH(3)COOH. Plant uptake of P, Ca and Mg was in the same order as their inputs in DFE but for Na; inputs were an order of magnitude greater than plant uptake. Replacement of NaOH by KOH resulted in increased accumulation of exchangeable K. The effects of added NaOH and KOH on promoting breakdown of soil aggregates during wet sieving (and formation of a < 0.25 mm size class) were similar. Replacement of H(2)PO(4) by HNO(3) is a viable but CH(3)COOH appears to have detrimental effects on plant growth. Replacement of NaOH by KOH lowers the likelihood of phytotoxic effects of Na, but K and Na have similar effects on disaggregation. PMID:22707204

  3. Influence of different acid and alkaline cleaning agents on the effects of irrigation of synthetic dairy factory effluent on soil quality, ryegrass growth and nutrient uptake.

    PubMed

    Liu, Y-Y; Haynes, R J

    2013-01-01

    The aim of this study was to examine the effects of replacement of phosphoric acid with nitric or acetic acid, and replacement of NaOH with KOH, as cleaning agents in dairy factories, on the effects that irrigation of dairy factory effluent (DFE) has on the soil-plant system. A 16-week greenhouse study was carried out in which the effects of addition of synthetic dairy factory effluent containing (a) milk residues alone or milk residues plus (b) H(3)PO(4)/NaOH, (c) H(3)PO(4)/HNO(3)/NaOH or (d) CH(3)COOH/KOH, on soil's chemical, physical and microbial properties and perennial ryegrass growth and nutrient uptake were investigated. The cumulative effect of DFE addition was to increase exchangeable Na, K, Ca, Mg, exchangeable sodium percentage, microbial biomass C and N and basal respiration in the soil. Dry matter yields of ryegrass were increased by additions of DFE other than that containing CH(3)COOH. Plant uptake of P, Ca and Mg was in the same order as their inputs in DFE but for Na; inputs were an order of magnitude greater than plant uptake. Replacement of NaOH by KOH resulted in increased accumulation of exchangeable K. The effects of added NaOH and KOH on promoting breakdown of soil aggregates during wet sieving (and formation of a < 0.25 mm size class) were similar. Replacement of H(2)PO(4) by HNO(3) is a viable but CH(3)COOH appears to have detrimental effects on plant growth. Replacement of NaOH by KOH lowers the likelihood of phytotoxic effects of Na, but K and Na have similar effects on disaggregation.

  4. Intestinal absorption, liver uptake, and excretion of /sup 3/H-folic acid in folic acid-deficient, alcohol-consuming nonhuman primates

    SciTech Connect

    Blocker, D.E.; Thenen, S.W.

    1987-09-01

    Nonhuman primates fed folic acid-deficient diets +/- 30% kcal ethanol were used to determine alcohol effects on megaloblastic anemia development and folate bioavailability. Lower hemoglobin (Hb) and red blood cell (RBC) counts and higher mean corpuscular volume (MCV) occurred after 13 wk in alcohol-fed monkeys, later in controls. Plasma, RBC, and liver folate declined and urinary formiminoglutamic acid (FIGLU) was elevated in both groups with FIGLU increasing more among alcohol-fed monkeys at 38 wk. After 40 wk, the bioavailability of oral /sup 3/H-folic acid was investigated and showed increased fecal and reduced urinary tritium excretion in alcohol-fed monkeys compared with controls while plasma uptake and liver and whole body tritium retention were similar in both groups. These observations demonstrate that chronic alcohol consumption impairs folate coenzymes, accelerates appearance of hematologic indices of megaloblastic anemia, and causes possible malabsorption of enterohepatically circulated folates in folate deficiency even when other essential nutrients are provided.

  5. The role of the cell cycle in the cellular uptake of folate-modified poly(l-amino acid) micelles in a cell population

    NASA Astrophysics Data System (ADS)

    Tang, Jihui; Liu, Ziwei; Ji, Fenqi; Li, Yao; Liu, Junjie; Song, Jian; Li, Jun; Zhou, Jianping

    2015-12-01

    Nanoparticles are widely recognized as a vehicle for tumor-targeted therapies. There are many factors that can influence the uptake of nanoparticles, such as the size of the nanoparticles, and/or their shape, elasticity, surface charge and even the cell cycle phase. However, the influence of the cell cycle on the active targeting of a drug delivery system has been unknown until now. In this study, we initially investigated the folate receptor α (FR-α) expression in different phases of HeLa cells by flow cytometric and immunocytochemical methods. The results obtained showed that FR-α expression was cell cycle-dependent, i.e. the S cells' folate receptor expression was the highest as the cell progressed through its cycle. Then, we used folate modified poly(l-amino acid) micelles (FA-PM) as an example to investigate the influence of the cell cycle on the active targeting drug delivery system. The results obtained indicated that the uptake of FA-PM by cells was influenced by the cell cycle phase, and the S cells took up the greatest number of folate conjugated nanoparticles. Our findings suggest that future studies on ligand-mediated active targeting preparations should consider the cell cycle, especially when this system is used for a cell cycle-specific drug.

  6. Uptake of dissolved free amino acids by four cold-water coral species from the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Gori, Andrea; Grover, Renaud; Orejas, Covadonga; Sikorski, Séverine; Ferrier-Pagès, Christine

    2014-01-01

    Dissolved organic matter, which contains many compounds such as lipids, sugars and amino acids, is an important source of carbon and nitrogen for several symbiotic and asymbiotic tropical coral species. However, there is still no information on its possible uptake by cold-water coral species. In this study, we demonstrated that dissolved organic matter, in the form of dissolved free amino acids (DFAA), is actively absorbed by four cold-water coral species from the Mediterranean Sea. Although the uptake rates observed with 3 μM DFAA concentration were one order of magnitude lower than those observed in tropical species, they corresponded to 12-50% of the daily excreted-nitrogen, and 16-89% of the daily respired-carbon of the cold-water corals. Consequently, DFAA, even at in situ concentrations lower than those tested in this study, can supply a significant amount of carbon and nitrogen to the corals, especially during periods when particulate food is scarce.

  7. Impact of acid effluent from Kawah Ijen crater lake on irrigated agricultural soils: Soil chemical processes and plant uptake

    NASA Astrophysics Data System (ADS)

    van Rotterdam-Los, A. M. D.; Heikens, A.; Vriend, S. P.; van Bergen, M. J.; van Gaans, P. F. M.

    2008-12-01

    Volcanogenic contamination of irrigation water, caused by effluent from the hyperacid Ijen crater lake, has severely affected the properties of agricultural soils in East Java, Indonesia. From a comparison of acidified topsoil with subsoil and with top- and subsoil in a reference area, we identified processes responsible for changes in soil and soil solution chemistry induced by acid irrigation water, with emphasis on the nutrients Ca, Mg, Fe, and Mn, and on Al, which may become phytotoxic under acid conditions in soils. Compositional data for bulk soil composition and selective extractions with 1 M KCl and 0.2 M acid ammonium oxalate are used in a mass balance approach to specify element fluxes, including uptake by rice plants. The results show that input via irrigation water has produced an increase in the total aluminum content in the affected topsoil, which is of the same order of magnitude as the increase in labile Al. High bioavailability of Al, as reflected by concentrations in KCl extracts, is consistent with elevated concentrations observed in rice plants. In contrast, and despite the high input via irrigation water, Ca and Mg concentrations have decreased in all measured soil fractions through dissolution of amorphous phases and minerals, and through competition of Al for adsorption sites on the exchange complex and plant roots. Strong leaching is also evident for Fe and especially Mn. In terms of the overall mass balance of the topsoil, plant uptake of Al, Ca, Fe, Mg and Mn is negligible. If the use of acid irrigation would be stopped and the soil pH were to increase to values above 4.5, the observed phytotoxicity of Al will be halted. However, crops may then become fully dependent on the input from irrigation water or fertilizer for essential elements, due to the previous removal from the topsoil through leaching.

  8. Genetically designed biomolecular capping system for mesoporous silica nanoparticles enables receptor-mediated cell uptake and controlled drug release

    NASA Astrophysics Data System (ADS)

    Datz, Stefan; Argyo, Christian; Gattner, Michael; Weiss, Veronika; Brunner, Korbinian; Bretzler, Johanna; von Schirnding, Constantin; Torrano, Adriano A.; Spada, Fabio; Vrabel, Milan; Engelke, Hanna; Bräuchle, Christoph; Carell, Thomas; Bein, Thomas

    2016-04-01

    Effective and controlled drug delivery systems with on-demand release and targeting abilities have received enormous attention for biomedical applications. Here, we describe a novel enzyme-based cap system for mesoporous silica nanoparticles (MSNs) that is directly combined with a targeting ligand via bio-orthogonal click chemistry. The capping system is based on the pH-responsive binding of an aryl-sulfonamide-functionalized MSN and the enzyme carbonic anhydrase (CA). An unnatural amino acid (UAA) containing a norbornene moiety was genetically incorporated into CA. This UAA allowed for the site-specific bio-orthogonal attachment of even very sensitive targeting ligands such as folic acid and anandamide. This leads to specific receptor-mediated cell and stem cell uptake. We demonstrate the successful delivery and release of the chemotherapeutic agent Actinomycin D to KB cells. This novel nanocarrier concept provides a promising platform for the development of precisely controllable and highly modular theranostic systems.Effective and controlled drug delivery systems with on-demand release and targeting abilities have received enormous attention for biomedical applications. Here, we describe a novel enzyme-based cap system for mesoporous silica nanoparticles (MSNs) that is directly combined with a targeting ligand via bio-orthogonal click chemistry. The capping system is based on the pH-responsive binding of an aryl-sulfonamide-functionalized MSN and the enzyme carbonic anhydrase (CA). An unnatural amino acid (UAA) containing a norbornene moiety was genetically incorporated into CA. This UAA allowed for the site-specific bio-orthogonal attachment of even very sensitive targeting ligands such as folic acid and anandamide. This leads to specific receptor-mediated cell and stem cell uptake. We demonstrate the successful delivery and release of the chemotherapeutic agent Actinomycin D to KB cells. This novel nanocarrier concept provides a promising platform for the

  9. Anti-1-Amino-3-18F-Fluorocyclobutane-1-Carboxylic Acid: Physiologic Uptake Patterns, Incidental Findings, and Variants That May Simulate Disease

    PubMed Central

    Schuster, David M.; Nanni, Cristina; Fanti, Stefano; Oka, Shuntaro; Okudaira, Hiroyuki; Inoue, Yusuke; Sörensen, Jens; Owenius, Rikard; Choyke, Peter; Turkbey, Baris; Bogsrud, Trond V.; Bach-Gansmo, Tore; Halkar, Raghuveer K.; Nye, Jonathon A.; Odewole, Oluwaseun A.; Savir-Baruch, Bital; Goodman, Mark M.

    2016-01-01

    Anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid (18F-FACBC) is a synthetic amino acid analog PET radiotracer undergoing clinical trials for the evaluation of prostate and other cancers. We aimed to describe common physiologic uptake patterns, incidental findings, and variants in patients who had undergone 18F-FACBC PET. Methods Sixteen clinical trials involving 611 18F-FACBC studies from 6 centers, which included dosimetry studies on 12 healthy volunteers, were reviewed. Qualitative observations of common physiologic patterns, incidental uptake, and variants that could simulate disease were recorded and compared with similar observations in studies of the healthy volunteers. Quantitative analysis of select data and review of prior published reports and observations were also made. Results The liver and pancreas demonstrated the most intense uptake. Moderate salivary and pituitary uptake and variable mild to moderate bowel activity were commonly visualized. Moderate bone marrow and mild muscle activity were present on early images, with marrow activity decreasing and muscle activity increasing with time. Brain and lungs demonstrated activity less than blood pool. Though 18F-FACBC exhibited little renal excretion or bladder uptake during the clinically useful early imaging time window, mild to moderate activity might accumulate in the bladder and interfere with evaluation of adjacent prostate bed and seminal vesicles in 5%–10% of patients. Uptake might also occur from benign processes such as infection, inflammation, prostatic hyperplasia, and metabolically active benign bone lesions such as osteoid osteoma. Conclusion Common physiologic uptake patterns were similar to those noted in healthy volunteers. The activity in organs followed the presence of amino acid transport and metabolism described with other amino acid–based PET radiotracers. As with other PET radiotracers such as 18F-FDG, focal nonphysiologic uptake may represent incidental malignancy

  10. Variation for N Uptake System in Maize: Genotypic Response to N Supply

    PubMed Central

    Garnett, Trevor; Plett, Darren; Conn, Vanessa; Conn, Simon; Rabie, Huwaida; Rafalski, J. Antoni; Dhugga, Kanwarpal; Tester, Mark A.; Kaiser, Brent N.

    2015-01-01

    An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate (NO3−) and ammonium (NH4+) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both NO3− and NH4+ increased with reduced N. Transcript levels of putative NO3− and NH4+ transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals. PMID:26617612

  11. Variation for N Uptake System in Maize: Genotypic Response to N Supply.

    PubMed

    Garnett, Trevor; Plett, Darren; Conn, Vanessa; Conn, Simon; Rabie, Huwaida; Rafalski, J Antoni; Dhugga, Kanwarpal; Tester, Mark A; Kaiser, Brent N

    2015-01-01

    An understanding of the adaptations made by plants in their nitrogen (N) uptake systems in response to reduced N supply is important to the development of cereals with enhanced N uptake efficiency (NUpE). Twenty seven diverse genotypes of maize (Zea mays, L.) were grown in hydroponics for 3 weeks with limiting or adequate N supply. Genotypic response to N was assessed on the basis of biomass characteristics and the activities of the nitrate ([Formula: see text]) and ammonium ([Formula: see text]) high-affinity transport systems. Genotypes differed greatly for the ability to maintain biomass with reduced N. Although, the N response in underlying biomass and N transport related characteristics was less than that for biomass, there were clear relationships, most importantly, lines that maintained biomass at reduced N maintained net N uptake with no change in size of the root relative to the shoot. The root uptake capacity for both [Formula: see text] and [Formula: see text] increased with reduced N. Transcript levels of putative [Formula: see text] and [Formula: see text] transporter genes in the root tissue of a subset of the genotypes revealed that predominately ZmNRT2 transcript levels responded to N treatments. The correlation between the ratio of transcripts of ZmNRT2.2 between the two N levels and a genotype's ability to maintain biomass with reduced N suggests a role for these transporters in enhancing NUpE. The observed variation in the ability to capture N at low N provides scope for both improving NUpE in maize and also to better understand the N uptake system in cereals. PMID:26617612

  12. Characterization of a Dipartite Iron Uptake System from Uropathogenic Escherichia coli Strain F11*

    PubMed Central

    Koch, Doreen; Chan, Anson C. K.; Murphy, Michael E. P.; Lilie, Hauke; Grass, Gregor; Nies, Dietrich H.

    2011-01-01

    In the uropathogenic Escherichia coli strain F11, in silico genome analysis revealed the dicistronic iron uptake operon fetMP, which is under iron-regulated control mediated by the Fur regulator. The expression of fetMP in a mutant strain lacking known iron uptake systems improved growth under iron depletion and increased cellular iron accumulation. FetM is a member of the iron/lead transporter superfamily and is essential for iron uptake by the Fet system. FetP is a periplasmic protein that enhanced iron uptake by FetM. Recombinant FetP bound Cu(II) and the iron analog Mn(II) at distinct sites. The crystal structure of the FetP dimer reveals a copper site in each FetP subunit that adopts two conformations: CuA with a tetrahedral geometry composed of His44, Met90, His97, and His127, and CuB, a second degenerate octahedral geometry with the addition of Glu46. The copper ions of each site occupy distinct positions and are separated by ∼1.3 Å. Nearby, a putative additional Cu(I) binding site is proposed as an electron source that may function with CuA/CuB displacement to reduce Fe(III) for transport by FetM. Together, these data indicate that FetMP is an additional iron uptake system composed of a putative iron permease and an iron-scavenging and potentially iron-reducing periplasmic protein. PMID:21596746

  13. Water uptake by a maize root system - An explicit numerical 3-dimensional simulation.

    NASA Astrophysics Data System (ADS)

    Leitner, Daniel; Schnepf, Andrea; Klepsch, Sabine; Roose, Tiina

    2010-05-01

    Water is one of the most important resources for plant growth and function. An accurate modelling of the unsaturated flow is not only substantial to predict water uptake but also important to describe nutrient movement regarding water saturation and transport. In this work we present a model for water uptake. The model includes the simultaneous flow of water inside the soil and inside the root network. Water saturation in the soil volume is described by the Richards equation. Water flow inside the roots' xylem is calculated using the Poiseuille law for water flow in a cylindrical tube. The water saturation in the soil as well as water uptake of the root system is calculated numerically in three dimensions. We study water uptake of a maize plant in a confined pot under different supply scenarios. The main improvement of our approach is that the root surfaces act as spatial boundaries of the soil volume. Therefore water influx into the root is described by a surface flux instead of a volume flux, which is commonly given by an effective sink term. For the numerical computation we use the following software: The 3-dimensional maize root architecture is created by a root growth model based on L-Systems (Leitner et al 2009). A mesh of the surrounding soil volume is created using the meshing software DistMesh (Persson & Strang 2004). Using this mesh the partial differential equations are solved with the finite element method using Comsol Multiphysics 3.5a. Modelling results are related to accepted water uptake models from literature (Clausnitzer & Hopmans 1994, Roose & Fowler 2004, Javaux et al 2007). This new approach has several advantages. By considering the individual roots it is possible to analyse the influence of overlapping depletion zones due to inter root competition. Furthermore, such simulations can be used to estimate the influence of simplifying assumptions that are made in the development of effective models. The model can be easily combined with a nutrient

  14. Methane uptake and emissions in a typical steppe grazing system during the grazing season

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoya; Zhang, Yingjun; Huang, Ding; Li, Zhiqiang; Zhang, Xiaoqing

    2015-03-01

    This study investigated the effects of livestock grazing on CH4 emissions by testing six grazing conditions at Guyuan State Key Monitoring and Research Station of Grassland Ecosystem (China) in 2011 and 2012. Under all grazing systems, steppe soils were measured to be CH4 sinks. The uptake of CH4 by grassland was primarily determined by topsoil (7 cm) temperature and soil (0-7 cm) moisture in grassland at short-term grazing and non-grazing. The cumulative uptake of CH4 during the grazing period for all conditions was 0.88-3.23 kg hm-2 CH4, and the highest level was observed in the continuously moderate grazing condition. Reducing grazing stocking in the short-term did not significantly change the uptake of CH4 when compared with continuously heavy grazing condition. Enteric CH4 emissions were not significantly affected by the grazing period or conditions. The uptake of CH4 by grassland soil offset 3.1-8.6% of the CH4 emissions from the grazing sheep and was most effective at the continuously moderate grazing condition. These findings imply that continuously moderate grazing is the best approach considered here for optimizing the soil as a sink for atmospheric CH4.

  15. Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Franck, Valerie M.; Brzezinski, Mark A.; Coale, Kenneth H.; Nelson, David M.

    We investigated the relative roles of Fe and silicic acid availabilities in regulating Si uptake rates across the Polar Frontal Zone in the Pacific Sector of the Southern Ocean (59-68°S, 170°W) during the US JGOFS Antarctic Environment Southern Ocean Process Study (AESOPS). Meridional gradients in silicic acid concentration ([Si(OH) 4]) of about 0.25-0.56 μM km -1 were observed in this area during austral spring and summer, 1997-1998, with [Si(OH) 4] ranging from <1 to 15 μM on the north side of the gradient to 40-60 μM on the south side. In two pairs of shipboard bottle-enrichment experiments conducted north and south of the Si gradient in spring and summer, we measured the effects of Fe, Zn and Si additions on 32Si(OH)4 and 15NO3- uptake rates, biogenic silica concentrations and Si(OH) 4 : NO 3- uptake ratios. Fe addition had little or no effect on Si uptake rates in enrichments conducted in the low-Si waters north of the Si gradient. However, Fe addition increased Si uptake rates 3-5 times over controls in enrichments conducted in the high-Si waters south of the gradient, in both spring and summer. Fe addition decreased Si(OH) 4 : NO 3- uptake ratios by 2-5 times, largely due to stimulation of NO 3- uptake rates. Zn addition had no effect on Si(OH) 4 and NO 3- uptake rates. Short-term (24 h) Si additions had varying effects on Si uptake rates, depending on season and location. In spring, additions of 40 μM Si to water from bottle enrichments, conducted north of the Si gradient (in situ [Si(OH) 4] ˜15 μM) did not increase Si uptake rates initially, but did increase uptake rates after 8 days. In the summer enrichment north of the Si gradient (in situ [Si(OH) 4] ˜5 μM), 50 μM Si additions doubled in situ Si uptake rates in the initial water collected for the enrichment, and increased Si uptake rates as much as 16-fold during the experiment. South of the Si gradient, where in situ [Si(OH) 4] was >40 μM in both spring and summer, Si addition had no effect

  16. Polymeric beads containing Cyanex 923 for actinide uptake from nitric acid medium: Studies with uranium and plutonium.

    PubMed

    Gujar, R B; Lakshmi, D Shanthana; Figoli, A; Mohapatra, P K

    2013-08-30

    Conventional phase inversion technique has been successfully applied for the preparation of the solid phase extractant (SPE), Cyanex 923 loaded polymer beads. Two types of polymer beads prepared by blending Polyetherether ketone with card (PEEKWC)/DMF with 5% Cyanex 923 (SPE-I, av bead size: 900μm) and 10% Cyanex 923(SPE-II, av. bead size: 1100μm) were evaluated for the uptake of actinide ions. The polymer beads were characterized by various physical methods such as thermal analysis, surface morphology analysis by SEM, EDAX techniques, etc. The polymer beads were used for the experiments involving the uptake of both U(VI) and Pu(IV) at tracer scale and U(VI) at milli molar concentrations from nitric acid feeds. The actinide ion uptake studies involved kinetics of metal ion sorption, adsorption isotherms, and column studies. The metal sorption capacities for U(VI) at 3M HNO3 were found to be 38.8±1.9mg and 54.5±1.7mg per g of SPE-I and SPE-II, respectively. The sorption isotherm analysis with Langmuir, D-R and Freundlisch isotherms indicated chemisorption monolayer mechanism. Column studies were also carried out using 4.5mL bed volume columns containing about 0.4 and 0.45g of SPE-I and SPE-II, respectively. The breakthrough profiles were obtained for U(VI) and the elution profiles were obtained using 1M Na2CO3 as the eluent.

  17. Thyroid metabolism in the recessive sex-linked dwarf female chicken. 4. The influence of exogenous thyroid hormones on amino acid uptake by plasma and tissues.

    PubMed

    Grandhi, R R; Brown, R G; Reinhart, B S; Summers, J D

    1975-03-01

    The influence of exogenous triiodothyronine (T3) or tetraiodothyronine (T4) on the incorporation of 3H-labelled methionine, alanine and lysine into plasma, liver and kidney was studied in 4 wk. old dwarf and non-dwarf female, White Leghorn chickens. The response to exogenous T3 or T4 of the birds was directly dependent on the dwarf status as well as the tissue and/or amino acid studied. In general, there was a decreased amino acid uptake by dwarfs and T3 and/or T4 depressed amino acid uptake in all combinations studied except for the uptake of lysine by the kidney of the dwarf. In that tissue, T4 administration caused a significant increase in lysine incorporation. The results found probably were due to different tissue amino compositions or rates of synthesis of proteins by dwarf birds when compared to normals and a differential sensitivity of dwarf birds to changed T3/T4 ratios.

  18. Amino acid transport across the tonoplast of vacuoles isolated from barley mesophyll protoplasts: Uptake of alanine, leucine, and glutamine. [Hordeum vulgare L

    SciTech Connect

    Dietz, K.J.; Jaeger, R.; Kaiser, G.; Martinoia, E. )

    1990-01-01

    Mesophyll protoplasts from leaves of well-fertilized barley (Hordeum vulgare L.) plants contained amino acids at concentrations as high as 120 millimoles per liter. With the exception of glutamic acid, which is predominantly localized in the cytoplasm, a major part of all other amino acids was contained inside the large central vacuole. Alanine, leucine, and glutamine are the dominant vacuolar amino acids in barley. Their transport into isolated vacuoles was studied using {sup 14}C-labeled amino acids. Uptake was slow in the absence of ATP. A three- to sixfold stimulation of uptake was observed after addition of ATP or adenylyl imidodiphosphate an ATP analogue not being hydrolyzed by ATPases. Other nucleotides were ineffective in increasing the rate of uptake. ATP-Stimulated amino acid transport was not dependent on the transtonoplast pH or membrane potential. p-Chloromercuriphenylsulfonic acid and n-ethyl maleimide increased transport independently of ATP. Neutral amino acids such as valine or leucine effectively decreased the rate of alanine transport. Glutamine and glycine were less effective or not effective as competitive inhibitors of alanine transport. The results indicate the existence of a uniport translocator specific for neutral or basic amino acids that is under control of metabolic effectors.

  19. Uptake and conversion of D-amino acids in Arabidopsis thaliana.

    PubMed

    Gördes, Dirk; Kolukisaoglu, Üner; Thurow, Kerstin

    2011-02-01

    The D-enantiomers of proteinogenic amino acids fulfill essential functions in bacteria, fungi and animals. Just in the plant kingdom, the metabolism and role of D-amino acids (D-AAs) still remains unclear, although plants have to cope with significant amounts of these compounds from microbial decay in the rhizosphere. To fill this gap of knowledge, we tested the inhibitory effects of D-AAs on plant growth and established a method to quantitate 16 out of 19 proteinogenic amino acids and their D-enantiomers in plant tissue extracts. Therefore, the amino acids in the extracts were derivatized with Marfey's reagent and separated by HPLC-MS. We used two ecotypes (Col-0 and C24) and a mutant (lht1) of the model plant Arabidopsis thaliana to determine the influence and fate of exogenously applied D-AAs. All of them were found in high concentrations in the plant extracts after application, even in lht1, which points to additional transporters facilitating the import of D-AAs. The addition of particular amino acids (D-Trp, D-Phe, D-Met and D-His) led to the accumulation of the corresponding L-amino acid. In almost all cases, the application of a D-AA resulted in the accumulation of D-Ala and D-Glu. The presented results indicate that soil borne D-AAs can actively be taken up and metabolized via central metabolic routes.

  20. An exposure system for measuring nasal and lung uptake of vapors in rats

    SciTech Connect

    Dahl, A.R.; Brookins, L.K.; Gerde, P.

    1995-12-01

    Inhaled gases and vapors often produce biological damage in the nasal cavity and lower respiratory tract. The specific site within the respirator tract at which a gas or vapor is absorbed strongly influences the tissues at risk to potential toxic effects; to predict or to explain tissue or cell specific toxicity of inhaled gases or vapors, the sites at which they are absorbed must be known. The purpose of the work reported here was to develop a system for determining nose and lung absorption of vapors in rats, an animal commonly used in inhalation toxicity studies. In summary, the exposure system described allows us to measure in the rate: (1) nasal absorption and desorption of vapors; (2) net lung uptake of vapors; and (3) the effects of changed breathing parameters on vapor uptake.

  1. An updated model for nitrate uptake modelling in plants. II. Assessment of active root involvement in nitrate uptake based on integrated root system age: measured versus modelled outputs.

    PubMed

    Malagoli, Philippe; Le Deunff, Erwan

    2014-05-01

    Background and Aims An updated version of a mechanistic structural-functional model was developed to predict nitrogen (N) uptake throughout the growth cycle by a crop of winter oilseed rape, Brassica napus, grown under field conditions. Methods The functional component of the model derives from a revisited conceptual framework that combines the thermodynamic Flow-Force interpretation of nitrate uptake isotherms and environmental and in planta effects on nitrate influx. Estimation of the root biomass (structural component) is based upon a combination of root mapping along the soil depth profile in the field and a relationship between the specific root length and external nitrate concentration. The root biomass contributing actively to N uptake was determined by introduction of an integrated root system age that allows assignment of a root absorption capacity at a specific age of the root. Key Results Simulations were well matched to measured data of N taken up under field conditions for three levels of N fertilization. The model outputs indicated that the two topsoil layers (0-30 and 30-60 cm) contained 75-88 % of the total root length and biomass, and accounted for 90-95 % of N taken up at harvest. Conclusions This conceptual framework provides a model of nitrate uptake that is able to respond to external nitrate fluctuations at both functional and structural levels.

  2. Behaviors of acrylamide/itaconic acid hydrogels in uptake of uranyl ions from aqueous solutions

    SciTech Connect

    Karadag, E.; Saraydin, D.; Gueven, O.

    1995-12-01

    In this study, adsorptions of uranyl ions from two different aqueous uranyl solutions by acrylamide-itaconic acid hydrogels were investigated by a spectroscopic method. The hydrogels were prepared by irradiating with {gamma}-radiation. In the experiment of uranyl ions adsorption, Type II adsorption was found. One gram of acrylamide-itaconic acid hydrogels sorbed 178-219 mg uranyl ions from the solutions of uranyl acetate, 42-76 mg uranyl ions from the aqueous solutions of uranyl nitrate, while acrylamide hydrogel did not sorb any uranyl ion. For the hydrogel containing 40 mg of itaconic acid and irradiated to 3.73 kGy, swelling of the hydrogels was observed in water (1660%), in the aqueous solution of uranyl acetate (730%), and in the aqueous solution of uranyl nitrate (580%). Diffusions of water onto hydrogels were a non-Fickian type of diffusion, whereas diffusions of uranyl ions were a Fickian type of diffusion.

  3. Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

    SciTech Connect

    McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D.

    1996-10-16

    This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

  4. Role of a SpoVA protein in dipicolinic acid uptake into developing spores of Bacillus subtilis.

    PubMed

    Li, Yunfeng; Davis, Andrew; Korza, George; Zhang, Pengfei; Li, Yong-qing; Setlow, Barbara; Setlow, Peter; Hao, Bing

    2012-04-01

    The proteins encoded by the spoVA operon, including SpoVAD, are essential for the uptake of the 1:1 chelate of pyridine-2,6-dicarboxylic acid (DPA(2,6)) and Ca(2+) into developing spores of the bacterium Bacillus subtilis. The crystal structure of B. subtilis SpoVAD has been determined recently, and a structural homology search revealed that SpoVAD shares significant structural similarity but not sequence homology to a group of enzymes that bind to and/or act on small aromatic molecules. We find that molecular docking placed DPA(2,6) exclusively in a highly conserved potential substrate-binding pocket in SpoVAD that is similar to that in the structurally homologous enzymes. We further demonstrate that SpoVAD binds both DPA(2,6) and Ca(2+)-DPA(2,6) with a similar affinity, while exhibiting markedly weaker binding to other DPA isomers. Importantly, mutations of conserved amino acid residues in the putative DPA(2,6)-binding pocket in SpoVAD essentially abolish its DPA(2,6)-binding capacity. Moreover, replacement of the wild-type spoVAD gene in B. subtilis with any of these spoVAD gene variants effectively eliminated DPA(2,6) uptake into developing spores in sporulation, although the variant proteins were still located in the spore inner membrane. Our results provide direct evidence that SpoVA proteins, in particular SpoVAD, are directly involved in DPA(2,6) movement into developing B. subtilis spores.

  5. The mechanisms of North Atlantic CO2 uptake in a large Earth System Model ensemble

    NASA Astrophysics Data System (ADS)

    Halloran, P. R.; Booth, B. B. B.; Jones, C. D.; Lambert, F. H.; McNeall, D. J.; Totterdell, I. J.; Völker, C.

    2015-07-01

    The oceans currently take up around a quarter of the carbon dioxide (CO2) emitted by human activity. While stored in the ocean, this CO2 is not influencing Earth's radiation budget; the ocean CO2 sink therefore plays an important role in mitigating global warming. CO2 uptake by the oceans is heterogeneous, with the subpolar North Atlantic being the strongest CO2 sink region. Observations over the last 2 decades have indicated that CO2 uptake by the subpolar North Atlantic sink can vary rapidly. Given the importance of this sink and its apparent variability, it is critical that we understand the mechanisms behind its operation. Here we explore the combined natural and anthropogenic subpolar North Atlantic CO2 uptake across a large ensemble of Earth System Model simulations, and find that models show a peak in sink strength around the middle of the century after which CO2 uptake begins to decline. We identify different drivers of change on interannual and multidecadal timescales. Short-term variability appears to be driven by fluctuations in regional seawater temperature and alkalinity, whereas the longer-term evolution throughout the coming century is largely occurring through a counterintuitive response to rising atmospheric CO2 concentrations. At high atmospheric CO2 concentrations the contrasting Revelle factors between the low latitude water and the subpolar gyre, combined with the transport of surface waters from the low latitudes to the subpolar gyre, means that the subpolar CO2 uptake capacity is largely satisfied from its southern boundary rather than through air-sea CO2 flux. Our findings indicate that: (i) we can explain the mechanisms of subpolar North Atlantic CO2 uptake variability across a broad range of Earth System Models; (ii) a focus on understanding the mechanisms behind contemporary variability may not directly tell us about how the sink will change in the future; (iii) to identify long-term change in the North Atlantic CO2 sink we should focus

  6. The mechanisms of North Atlantic CO2 uptake in a large Earth System Model ensemble

    NASA Astrophysics Data System (ADS)

    Halloran, P. R.; Booth, B. B. B.; Jones, C. D.; Lambert, F. H.; McNeall, D. J.; Totterdell, I. J.; Völker, C.

    2014-10-01

    The oceans currently take up around a quarter of the carbon dioxide (CO2) emitted by human activity. While stored in the ocean, this CO2 is not influencing Earth's radiation budget; the ocean CO2 sink therefore plays an important role in mitigating global warming. CO2 uptake by the oceans is heterogeneous, with the subpolar North Atlantic being the strongest CO2 sink region. Observations over the last two decades have indicated that CO2 uptake by the subpolar North Atlantic sink can vary rapidly. Given the importance of this sink and its apparent variability, it is critical that we understand the mechanisms behind its operation. Here we explore subpolar North Atlantic CO2 uptake across a large ensemble of Earth System Model simulations, and find that models show a peak in sink strength around the middle of the century after which CO2 uptake begins to decline. We identify different drivers of change on interannual and multidecadal timescales. Short-term variability appears to be driven by fluctuations in regional seawater temperature and alkalinity, whereas the longer-term evolution throughout the coming century is largely occurring through a counterintuitive response to rising atmospheric CO2 concentrations. At high atmospheric CO2 concentrations the contrasting Ravelle factors between the subtropical and subpolar gyres, combined with the transport of surface waters from the subtropical to subpolar gyre, means that the subpolar CO2 uptake capacity is largely satisfied from its southern boundary rather than through air-sea CO2 flux. Our findings indicate that: (i) we can explain the mechanisms of subpolar North Atlantic CO2 uptake variability across a broad range of Earth System Models, (ii) a focus on understanding the mechanisms behind contemporary variability may not directly tell us about how the sink will change in the future, (iii) to identify long-term change in the North Atlantic CO2 sink we should focus observational resources on monitoring subtropical as

  7. Root-zone acidity and nitrogen source affects Typha latifolia L. growth and uptake kinetics of ammonium and nitrate.

    PubMed

    Brix, Hans; Dyhr-Jensen, Kirsten; Lorenzen, Bent

    2002-12-01

    The NH(4)(+) and NO(3)(-) uptake kinetics by Typha latifolia L. were studied after prolonged hydroponics growth at constant pH 3.5, 5.0, 6.5 or 7.0 and with NH(4)(+) or NO(3)(-) as the sole N-source. In addition, the effects of pH and N source on H(+) extrusion and adenine nucleotide content were examined. Typha latifolia was able to grow with both N sources at near neutral pH levels, but the plants had higher relative growth rates, higher tissue concentrations of the major nutrients, higher contents of adenine nucleotides, and higher affinity for uptake of inorganic nitrogen when grown on NH(4)(+). Growth almost completely stopped at pH 3.5, irrespective of N source, probably as a consequence of pH effects on plasma membrane integrity and H(+) influx into the root cells. Tissue concentrations of the major nutrients and adenine nucleotides were severely reduced at low pH, and the uptake capacity for inorganic nitrogen was low, and more so for NO(3)(-)-fed than for NH(4)(+)-fed plants. The maximum uptake rate, V(max), was highest for NH(4)(+) at pH 6.5 (30.9 micro mol h(-1) g(-1) root dry weight) and for NO(3)(-) at pH 5.0 (31.7 micro mol h(-1) g(-1) root dry weight), and less than 10% of these values at pH 3.5. The affinity for uptake as estimated by the half saturation constant, K((1/2)), was lowest at low pH for NH(4)(+) and at high pH for NO(3)(-). The changes in V(max) and K((1/2)) were thus consistent with the theory of increasing competition between cations and H(+) at low pH and between anions and OH(-) at high pH. C(min) was independent of pH, but slightly higher for NO(3)(-) than for NH(4)(+) (C(min)(NH(4)(+)) approximately 0.8 mmol m(-3); C(min)(NO(3)(-)) approximately 2.8 mmol m(-3)). The growth inhibition at low pH was probably due to a reduced nutrient uptake and a consequential limitation of growth by nutrient stress. Typha latifolia seems to be well adapted to growth in wetland soils where NH(4)(+) is the prevailing nitrogen compound, but very low p

  8. Uptake of (N-Me-3H)-choline by synaptosomes from the central nervous system of Locusta migratoria

    SciTech Connect

    Breer, H.

    1982-03-01

    The accumulation of 3H-choline by isolated synaptosomes from the central nervous system of locust was studied at concentrations varying from 0.05 to 40 microM. Kinetic analysis of the saturable process revealed a high-affinity and a low-affinity system. The high-affinity uptake was competitively inhibited by hemicholinium-3 and was absolutely dependent on external sodium. Elevated potassium concentrations inhibited choline uptake. The choline uptake by insect synaptosomes was found to be remarkably resistant to a variety of metabolic inhibitors. The reduced choline uptake under depolarizing conditions (high potassium concentration or veratridine) in the absence of calcium implies that electrochemical gradients are important for high-affinity choline uptake. Depolarization of preloaded synaptosomes under appropriate conditions resulted in a significant release of newly accumulated choline radioactivity.

  9. Amino acid uptake profiling of wild type and recombinant Streptomyces lividans TK24 batch fermentations.

    PubMed

    D'Huys, Pieter-Jan; Lule, Ivan; Van Hove, Sven; Vercammen, Dominique; Wouters, Christine; Bernaerts, Kristel; Anné, Jozef; Van Impe, Jan F M

    2011-04-10

    Streptomyces lividans is considered an interesting host for the secretory production of heterologous proteins. To obtain a good secretion yield of heterologous proteins, the availability of suitable nitrogen sources in the medium is required. Often, undefined mixtures of amino acids are used to improve protein yields. However, the understanding of amino acid utilization as well as their contribution to the heterologous protein synthesis is poor. In this paper, amino acid utilization by wild type and recombinant S. lividans TK24 growing on a minimal medium supplemented with casamino acids is profiled by intensive analysis of the exometabolome (metabolic footprint) as a function of time. Dynamics of biomass, substrates, by-products and heterologous protein are characterized, analyzed and compared. As an exemplary protein mouse Tumor Necrosis Factor Alpha (mTNF-α) is considered. Results unveil preferential glutamate and aspartate assimilation, together with glucose and ammonium, but the associated high biomass growth rate is unfavorable for protein production. Excretion of organic acids as well as alanine is observed. Pyruvate and alanine overflow point at an imbalance between carbon and nitrogen catabolism and biosynthetic fluxes. Lactate secretion is probably related to clump formation. Heterologous protein production induces a slowdown in growth, denser clump formation and a shift in metabolism, as reflected in the altered substrate requirements and overflow pattern. Besides glutamate and aspartate, most amino acids are catabolized, however, their exact contribution in heterologous protein production could not be seized from macroscopic quantities. The metabolic footprints presented in this paper provide a first insight into the impact and relevance of amino acids on biomass growth and protein production. Type and availability of substrates together with biomass growth rate and morphology affect the protein secretion efficiency and should be optimally controlled

  10. Effects of carboxylic acids on the uptake of non-transferrin-bound iron by astrocytes.

    PubMed

    Keenan, Belinda M; Robinson, Stephen R; Bishop, Glenda M

    2010-01-01

    The concentrations of non-transferrin-bound iron are elevated in the brain during pathological conditions such as stroke and Alzheimer's disease. Astrocytes are specialised for sequestering this iron, however little is known about the mechanisms involved. Carboxylates, such as citrate, have been reported to facilitate iron uptake by intestinal cells. Citrate binds iron and limits its redox activity. The presence of high citrate concentrations in the interstitial fluid of the brain suggests that citrate may be an important ligand for iron transport by astrocytes. This study investigates whether iron accumulation by cultured rat astrocytes is facilitated by citrate or other carboxylates. Contrary to expectations, citrate, tartrate and malate were found to block iron accumulation in a concentration-dependent manner; alpha-ketoglutarate had limited effects, while fumarate, succinate and glutarate had no effect. This blockade was not due to an inhibition of ferric reductase activity. Instead, it appeared to be related to the capacity of these carboxylates to bind iron, since phosphate, which also binds iron, diminished the capacity of citrate, tartrate and malate to block the cellular accumulation of iron. These findings raise the possibility that citrate may have therapeutic potential in the management of neurodegenerative conditions that involve cellular iron overload.

  11. Factors Influencing the Diversity of Iron Uptake Systems in Aquatic Microorganisms

    PubMed Central

    Desai, Dhwani K.; Desai, Falguni D.; LaRoche, Julie

    2012-01-01

    Iron (Fe) is an essential micronutrient for many processes in all living cells. Dissolved Fe (dFe) concentrations in the ocean are of the order of a few nM, and Fe is often a factor limiting primary production. Bioavailability of Fe in aquatic environments is believed to be primarily controlled through chelation by Fe-binding ligands. Marine microbes have evolved different mechanisms to cope with the scarcity of bioavailable dFe. Gradients in dFe concentrations and diversity of the Fe-ligand pool from coastal to open ocean waters have presumably imposed selection pressures that should be reflected in the genomes of microbial communities inhabiting the pelagic realm. We applied a hidden Markov model (HMM)-based search for proteins related to cellular iron metabolism, and in particular those involved in Fe uptake mechanisms in 164 microbial genomes belonging to diverse taxa and occupying different aquatic niches. A multivariate statistical approach demonstrated that in phototrophic organisms, there is a clear influence of the ecological niche on the diversity of Fe uptake systems. Extending the analyses to the metagenome database from the Global Ocean Sampling expedition, we demonstrated that the Fe uptake and homeostasis mechanisms differed significantly across marine niches defined by temperatures and dFe concentrations, and that this difference was linked to the distribution of microbial taxa in these niches. Using the dN/dS ratios (which signify the rate of non-synonymous mutations) of the nucleotide sequences, we identified that genes encoding for TonB, Ferritin, Ferric reductase, IdiA, ZupT, and Fe2+ transport proteins FeoA and FeoB were evolving at a faster rate (positive selection pressure) while genes encoding ferrisiderophore, heme and Vitamin B12 uptake systems, siderophore biosynthesis, and IsiA and IsiB were under purifying selection pressure (evolving slowly). PMID:23087680

  12. Tracking the diurnal signal of plant water uptake through the hydrologic system

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Hassler, Sibylle; Heidbüchel, Ingo; Weiler, Markus; Simard, Sonia; Güntner, Andreas; Heinrich, Ingo

    2015-04-01

    Plant water uptake during summer is characterized by strong diurnal fluctuations. As a result a diurnal sink term is imposed on catchment storage, affecting the unsaturated zone, sometimes the saturated zone and even streamflow. Detecting this signal and understanding its propagation through the hydrological system may help to better quantify eco-hydrological connectivity. The extent and strength of the propagation of this signal from plant to soil to ground- and stream water was investigated with a unique setup of 46 field sites in Luxemburg and 15 field sites in Germany. These sites cover a range of geologies, soils, topographies and types of vegetation. Vegetation types include grassland, pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 3-5 soil moisture profiles, matrix potential, piezometers and sapflow sensors (as proxy for plant water uptake) as well as standard climate data. At sites with access to a stream, discharge or water level is also recorded. Signal strength (amplitude of diurnal fluctuations) can thus be traced through the system and gives an indication of the physical sphere of influence of plant water uptake i.e. the "eco-hydro-connectivity". Temporal dynamics of signal strength furthermore suggest a shifting spatial distribution of root water uptake with time. The analysis of time lags (or phase shifts) between daily fluctuations in temperature, radiation, sapflow, soil water, groundwater and streamflow gives further insights into the processes driving and propagating these signals and inter-site comparison allows for the investigation of local controls.

  13. Generation, Release, and Uptake of the NAD Precursor Nicotinic Acid Riboside by Human Cells.

    PubMed

    Kulikova, Veronika; Shabalin, Konstantin; Nerinovski, Kirill; Dölle, Christian; Niere, Marc; Yakimov, Alexander; Redpath, Philip; Khodorkovskiy, Mikhail; Migaud, Marie E; Ziegler, Mathias; Nikiforov, Andrey

    2015-11-01

    NAD is essential for cellular metabolism and has a key role in various signaling pathways in human cells. To ensure proper control of vital reactions, NAD must be permanently resynthesized. Nicotinamide and nicotinic acid as well as nicotinamide riboside (NR) and nicotinic acid riboside (NAR) are the major precursors for NAD biosynthesis in humans. In this study, we explored whether the ribosides NR and NAR can be generated in human cells. We demonstrate that purified, recombinant human cytosolic 5'-nucleotidases (5'-NTs) CN-II and CN-III, but not CN-IA, can dephosphorylate the mononucleotides nicotinamide mononucleotide and nicotinic acid mononucleotide (NAMN) and thus catalyze NR and NAR formation in vitro. Similar to their counterpart from yeast, Sdt1, the human 5'-NTs require high (millimolar) concentrations of nicotinamide mononucleotide or NAMN for efficient catalysis. Overexpression of FLAG-tagged CN-II and CN-III in HEK293 and HepG2 cells resulted in the formation and release of NAR. However, NAR accumulation in the culture medium of these cells was only detectable under conditions that led to increased NAMN production from nicotinic acid. The amount of NAR released from cells engineered for increased NAMN production was sufficient to maintain viability of surrounding cells unable to use any other NAD precursor. Moreover, we found that untransfected HeLa cells produce and release sufficient amounts of NAR and NR under normal culture conditions. Collectively, our results indicate that cytosolic 5'-NTs participate in the conversion of NAD precursors and establish NR and NAR as integral constituents of human NAD metabolism. In addition, they point to the possibility that different cell types might facilitate each other's NAD supply by providing alternative precursors. PMID:26385918

  14. Endothelial lipase modulates pressure overload-induced heart failure through alternative pathway for fatty acid uptake.

    PubMed

    Nakajima, Hideto; Ishida, Tatsuro; Satomi-Kobayashi, Seimi; Mori, Kenta; Hara, Tetsuya; Sasaki, Naoto; Yasuda, Tomoyuki; Toh, Ryuji; Tanaka, Hidekazu; Kawai, Hiroya; Hirata, Ken-ichi

    2013-05-01

    Lipoprotein lipase has been considered as the only enzyme capable of generating lipid-derived fatty acids for cardiac energy. Endothelial lipase is another member of the triglyceride lipase family and hydrolyzes high-density lipoproteins. Although endothelial lipase is expressed in the heart, its function remains unclear. We assessed the role of endothelial lipase in the genesis of heart failure. Pressure overload-induced cardiac hypertrophy was generated in endothelial lipase(-/-) and wild-type mice by ascending aortic banding. Endothelial lipase expression in cardiac tissues was markedly elevated in the early phase of cardiac hypertrophy in wild-type mice, whereas lipoprotein lipase expression was significantly reduced. Endothelial lipase(-/-) mice showed more severe systolic dysfunction with left-ventricular dilatation compared with wild-type mice in response to pressure overload. The expression of mitochondrial fatty acid oxidation-related genes, such as carnitine palmitoyltransferase-1 and medium-chain acyl coenzyme A dehydrogenase, was significantly lower in the heart of endothelial lipase(-/-) mice than in wild-type mice. Also, endothelial lipase(-/-) mice had lower myocardial adenosine triphosphate levels than wild-type mice after aortic banding. In cultured cardiomyocytes, endothelial lipase was upregulated by inflammatory stimuli, whereas lipoprotein lipase was downregulated. Endothelial lipase-overexpression in cardiomyocytes resulted in an upregulation of fatty acid oxidation-related enzymes and intracellular adenosine triphosphate accumulation in the presence of high-density lipoprotein. Endothelial lipase may act as an alternative candidate to provide fatty acids to the heart and regulate cardiac function. This effect seemed relevant particularly in the diseased heart, where lipoprotein lipase action is downregulated. PMID:23460280

  15. Raman microscopic imaging of cells and applications monitoring the uptake of drug delivery systems

    NASA Astrophysics Data System (ADS)

    Matthäus, Christian; Chernenko, Tatyana; Quintero, Luis; Milan, Lara; Kale, Amit; Amiji, Mansoor; Torchilin, Vladimir; Diem, Max

    2008-04-01

    Raman spectroscopy, in combination with optical microscopy provides a new non-invasive method to asses and image cellular processes. Based on the spectral signatures of a cell's components, it is possible to image cellular organelles such as the nucleus, chromatin, mitochondria or lipid bodies, at the resolution of conventional microscopy. Several multivariate algorithms, for example hierarchical cluster analysis or orthogonal subspace projection, may be used to reconstruct an image of a cell. The noninvasive character of the technique, as well as the associated chemical information, may offer advantages over other imaging techniques such as fluorescence microscopy. Currently of particular interest are uptake and intracellular fate of various pharmaceutical nanocarriers, which are widely used for drug delivery purposes, including intracellular drug and gene delivery. We have imaged the uptake and distribution patterns of several carrier systems over time. In order to distinguish the species of interest from their cellular environment spectroscopically, the carrier particles or the drug load itself may be labeled with deuterium. Here, we introduce the concept of Raman imaging in combination with vertex component data analysis to follow the uptake of nanocarriers based on phospholipids as well as biodegradable polymers.

  16. Synthetic nanoparticles camouflaged with biomimetic erythrocyte membranes for reduced reticuloendothelial system uptake

    NASA Astrophysics Data System (ADS)

    Rao, Lang; Xu, Jun-Hua; Cai, Bo; Liu, Huiqin; Li, Ming; Jia, Yan; Xiao, Liang; Guo, Shi-Shang; Liu, Wei; Zhao, Xing-Zhong

    2016-02-01

    Suppression of the reticuloendothelial system (RES) uptake is one of the most challenging tasks in nanomedicine. Coating stratagems using polymers, such as poly(ethylene glycol) (PEG), have led to great success in this respect. Nevertheless, recent observations of immunological response toward these synthetic polymers have triggered a search for better alternatives. In this work, natural red blood cell (RBC) membranes are camouflaged on the surface of Fe3O4 nanoparticles for reducing the RES uptake. In vitro macrophage uptake, in vivo biodistribution and pharmacokinetic studies demonstrate that the RBC membrane is a superior alternative to the current gold standard PEG for nanoparticle ‘stealth’. Furthermore, we systematically investigate the in vivo potential toxicity of RBC membrane-coated nanoparticles by blood biochemistry, whole blood panel examination and histology analysis based on animal models. The combination of synthetic nanoparticles and natural cell membranes embodies a novel and biomimetic nanomaterial design strategy and presents a compelling property of functional materials for a broad range of biomedical applications.

  17. Computational screening of iodine uptake in zeolitic imidazolate frameworks in a water-containing system.

    PubMed

    Yuan, Yue; Dong, Xiuqin; Chen, Yifei; Zhang, Minhua

    2016-08-17

    Iodine capture is of great environmental significance due to the high toxicity and volatility of I2. Here we conduct a systematic computational investigation of iodine adsorption in zeolitic imidazolate frameworks (ZIFs) by adopting the grand canonical Monte Carlo (GCMC) simulation and the density functional theory (DFT) method. The results confirm the vital structural factors for iodine adsorption at 298 K and moderate pressures including metal sites, organic linkers, symmetry, and topology types. The uptake will be enhanced by active metal sites, the simple imidazolate linker and single asymmetric linkers with polar functional groups. The symmetry effect is stronger than the surface properties. Meanwhile low steric hindrance is more beneficial than polar functional groups to iodine adsorption. The specific topology types like mer bringing large surface areas and large diameter cages result in high iodine capacities. Iodine molecules tend to locate in cages with large diameters and aggregates along the sides of cages. In contrast, water prefers small diameter cages. In hydrophilic materials, water has a negative impact on iodine uptake due to its similar adsorption sites to iodine. The selectivity of iodine over water increases with increasing water content due to the large diameter cages of ZIFs. This work proves that ZIFs can be identified as efficient and economical adsorbents with high diversity for iodine in a water-containing system. Furthermore, it provides comprehensive insights into key structural factors for iodine uptake and separation in silver-free porous solids. PMID:27499079

  18. Examining the Uptake of Central Nervous System Drugs and Candidates across the Blood-Brain Barrier.

    PubMed

    Summerfield, Scott G; Zhang, Yanyan; Liu, Houfu

    2016-08-01

    Assessing the equilibration of the unbound drug concentrations across the blood-brain barrier (Kp,uu) has progressively replaced the partition coefficient based on the ratio of the total concentration in brain tissue to blood (Kp). Here, in vivo brain distribution studies were performed on a set of central nervous system (CNS)-targeted compounds in both rats and P-glycoprotein (P-gp) genetic knockout mice. Several CNS drugs are characterized by Kp,uu values greater than unity, inferring facilitated uptake across the rodent blood-brain barrier (BBB). Examples are shown in which Kp,uu also increases above unity on knockout of P-gp, highlighting the composite nature of this parameter with respect to facilitated BBB uptake, efflux, and passive diffusion. Several molecules with high Kp,uu values share common structural elements, whereas uptake across the BBB appears more prevalent in the CNS-targeted drug set than the chemical templates being generated within the current lead optimization paradigm. Challenges for identifying high Kp,uu compounds are discussed in the context of acute versus steady-state data and cross-species differences. Evidently, there is a need for better predictive models of human brain Kp,uu. PMID:27194478

  19. Synthetic nanoparticles camouflaged with biomimetic erythrocyte membranes for reduced reticuloendothelial system uptake.

    PubMed

    Rao, Lang; Xu, Jun-Hua; Cai, Bo; Liu, Huiqin; Li, Ming; Jia, Yan; Xiao, Liang; Guo, Shi-Shang; Liu, Wei; Zhao, Xing-Zhong

    2016-02-26

    Suppression of the reticuloendothelial system (RES) uptake is one of the most challenging tasks in nanomedicine. Coating stratagems using polymers, such as poly(ethylene glycol) (PEG), have led to great success in this respect. Nevertheless, recent observations of immunological response toward these synthetic polymers have triggered a search for better alternatives. In this work, natural red blood cell (RBC) membranes are camouflaged on the surface of Fe3O4 nanoparticles for reducing the RES uptake. In vitro macrophage uptake, in vivo biodistribution and pharmacokinetic studies demonstrate that the RBC membrane is a superior alternative to the current gold standard PEG for nanoparticle 'stealth'. Furthermore, we systematically investigate the in vivo potential toxicity of RBC membrane-coated nanoparticles by blood biochemistry, whole blood panel examination and histology analysis based on animal models. The combination of synthetic nanoparticles and natural cell membranes embodies a novel and biomimetic nanomaterial design strategy and presents a compelling property of functional materials for a broad range of biomedical applications.

  20. Examining the Uptake of Central Nervous System Drugs and Candidates across the Blood-Brain Barrier.

    PubMed

    Summerfield, Scott G; Zhang, Yanyan; Liu, Houfu

    2016-08-01

    Assessing the equilibration of the unbound drug concentrations across the blood-brain barrier (Kp,uu) has progressively replaced the partition coefficient based on the ratio of the total concentration in brain tissue to blood (Kp). Here, in vivo brain distribution studies were performed on a set of central nervous system (CNS)-targeted compounds in both rats and P-glycoprotein (P-gp) genetic knockout mice. Several CNS drugs are characterized by Kp,uu values greater than unity, inferring facilitated uptake across the rodent blood-brain barrier (BBB). Examples are shown in which Kp,uu also increases above unity on knockout of P-gp, highlighting the composite nature of this parameter with respect to facilitated BBB uptake, efflux, and passive diffusion. Several molecules with high Kp,uu values share common structural elements, whereas uptake across the BBB appears more prevalent in the CNS-targeted drug set than the chemical templates being generated within the current lead optimization paradigm. Challenges for identifying high Kp,uu compounds are discussed in the context of acute versus steady-state data and cross-species differences. Evidently, there is a need for better predictive models of human brain Kp,uu.

  1. Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution.

    PubMed

    Görner, Helmut

    2007-05-25

    The photolysis of lumichrome, riboflavin, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) was studied in air-saturated aqueous solution at room temperature in the presence of appropriate electron donors: ascorbic acid, aromatic amino acids or amines, e.g. ethylenediaminetetraacetate (EDTA). The overall reaction is conversion of oxygen via the hydroperoxyl/superoxide radical into hydrogen peroxide. The quantum yield of oxygen uptake increases with the donor concentration, e.g. up to 0.3 for riboflavin, FMN or FAD in the presence of EDTA or ascorbic acid (0.3-10mM). The formation of H(2)O(2) is initiated by quenching of the acceptor triplet state by the electron donor and subsequent reaction of the semiquinone radical with oxygen. Specific properties of flavins are discussed including the radicals involved and the pH and concentration dependences. The quantum yield of photodegradation is low under air, but substantial under argon, where the major product absorbing in the visible spectral range is the corresponding hydroquinone. PMID:17395476

  2. Tundra plant uptake of amino acid and NH{sub 4}{sup +} nitrogen in situ: Plants compete well for amino acid N{sup 1}

    SciTech Connect

    Schimel, J.P.; Chapin, F.S. III

    1996-10-01

    Traditional models of nutrient cycling assume that soil microorganisms must decompose organic matter, releasing inorganic N, to make N available to plants. Several lines of evidence have raised doubts about this assumption in arctic tundra, but no firm evidence existed. Here we demonstrate that Eriophorum vaginatum and Carex aquatilis, two tundra sedges, compete well for glycine and asparate N relative to NH{sub 4}{sup +} in situ. At relatively high concentrations (25 {mu}g N/g soil), during the peak of the season, E. vaginatum took up amino acid N more rapidly than NH{sub 4}{sup +}, while later in the season and at lower concentrations (2-4 {mu}g N/g soil) both E. vaginatum and C. aqualtilis took up glycine N and NH{sub 4}{sup +} at similar rates. These results are incompatible with a simple mechanism of amino acid mineralization followed by plant uptake of the released N. These results indicate that these tundra plants have active mechanisms for enhancing their access to amino acid N in situ. 18 refs., 4 tabs.

  3. Efficient Docosahexaenoic Acid Uptake by the Brain from a Structured Phospholipid.

    PubMed

    Hachem, Mayssa; Géloën, Alain; Van, Amanda Lo; Foumaux, Baptiste; Fenart, Laurence; Gosselet, Fabien; Da Silva, Pedro; Breton, Gildas; Lagarde, Michel; Picq, Madeleine; Bernoud-Hubac, Nathalie

    2016-07-01

    Docosahexaenoic acid (DHA) is the main essential omega-3 fatty acid in brain tissues required for normal brain development and function. An alteration of brain DHA in neurodegenerative diseases such as Alzheimer's and Parkinson's is observed. Targeted intake of DHA to the brain could compensate for these deficiencies. Blood DHA is transported across the blood-brain barrier more efficiently when esterified at the sn-2 position of lyso-phosphatidylcholine. We used a structured phosphatidylcholine to mimic 2-docosahexaenoyl-lysoPC (lysoPC-DHA), named AceDoPC (1-acetyl,2-docosahexaenoyl-glycerophosphocholine), that may be considered as a stabilized form of the physiological lysoPC-DHA and that is neuroprotective in experimental ischemic stroke. The aim of the present study was to investigate whether AceDoPC is a relevant delivery form of DHA to the brain in comparison with other forms of the fatty acid. By combining in vitro and in vivo experiments, our findings report for the first time that AceDoPC is a privileged and specific carrier of DHA to the brain, when compared with DHA-containing PC and non-esterified DHA. We also show that AceDoPC was hydrolyzed, in part, into lysoPC-DHA. Ex vivo autoradiography of rat brain reveals that DHA from AceDoPC was localized in specific brain regions playing key roles in memory, thoughts, and cognitive functions. Finally, using molecular modeling approaches, we demonstrate that electrostatic and lipophilic potentials are distributed very similarly at the surfaces of AceDoPC and lysoPC-DHA. Our findings identify AceDoPC as an efficient way to specifically target DHA to the brain, which would allow potential preventive and therapeutic approaches for neurological diseases. PMID:26041661

  4. Homogenization, lyophilization or acid-extraction of meat products improves iron uptake from cereal-meat product combinations in an in vitro digestion/Caco-2 cell model.

    PubMed

    Pachón, Helena; Stoltzfus, Rebecca J; Glahn, Raymond P

    2009-03-01

    The effect of processing (homogenization, lyophilization, acid-extraction) meat products on iron uptake from meat combined with uncooked iron-fortified cereal was evaluated using an in vitro digestion/Caco-2 cell model. Beef was cooked, blended to create smaller meat particles, and combined with electrolytic iron-fortified infant rice cereal. Chicken liver was cooked and blended, lyophilized, or acid-extracted, and combined with FeSO4-fortified wheat flour. In the beef-cereal combination, Caco-2 cell iron uptake, assessed by measuring the ferritin formed by cells, was greater when the beef was blended for the greatest amount of time (360 s) compared with 30 s (P < 0.05). Smaller liver particles (blended for 360 s or lyophilized) significantly enhanced iron uptake compared to liver blended for 60 s (P < 0.001) in the liver-flour combination. Compared to liver blended for 60 s, acid-extraction of liver significantly enhanced iron uptake (P = 0.03) in the liver-flour combination. Homogenization of beef and homogenization, lyophilization, or acid-extraction of chicken liver increases the enhancing effect of meat products on iron absorption in iron-fortified cereals.

  5. Arbuscular mycorrhizal fungi and rhizobium facilitate nitrogen uptake and transfer in soybean/maize intercropping system

    PubMed Central

    Meng, Lingbo; Zhang, Aiyuan; Wang, Fei; Han, Xiaoguang; Wang, Dejiang; Li, Shumin

    2015-01-01

    The tripartite symbiosis between legumes, rhizobia and mycorrhizal fungi are generally considered to be beneficial for the nitrogen (N) uptake of legumes, but the facilitation of symbiosis in legume/non-legume intercropping systems is not clear. Therefore, the aims of the research are as follows: (1) to verify if the dual inoculation can facilitate the N uptake and N transfer in maize/soybean intercropping systems and (2) to calculate how much N will be transferred from soybean to maize. A pot experiment with different root separations [solid barrier, mesh (30 μm) barrier and no barrier] was conducted, and the 15N isotopic tracing method was used to calculate how much N transferred from soybean to maize inoculated with arbuscular mycorrhizal fungi (AMF) and rhizobium in a soybean (Glycine max L.cv. Dongnong No. 42)/maize (Zea mays L.cv. Dongnong No. 48) intercropping system. Compared with the Glomus mosseae inoculation (G.m.), Rhizobium SH212 inoculation (SH212), no inoculation (NI), the dual inoculation (SH212+G.m.) increased the N uptake of soybean by 28.69, 39.58, and 93.07% in a solid barrier system. N uptake of maize inoculated with both G. mosseae and rhizobium was 1.20, 1.28, and 1.68 times more than that of G.m., SH212 and NI, respectively, in solid barrier treatments. In addition, the amount of N transferred from soybean to maize in a dual inoculation system with a mesh barrier was 7.25, 7.01, and 11.45 mg more than that of G.m., SH212 and NI and similarly, 6.40, 7.58, and 12.46 mg increased in no barrier treatments. Inoculating with both AMF and rhizobium in the soybean/maize intercropping system improved the N fixation efficiency of soybean and promoted N transfer from soybean to maize, resulting in the improvement of yield advantages of legume/non-legume intercropping. PMID:26029236

  6. Uptake of algal carbon and the synthesis of an "essential" fatty acid by Uvigerina ex. gr. semiornata (Foraminifera) within the Pakistan margin oxygen minimum zone: evidence from fatty acid biomarker and 13C tracer experiments

    NASA Astrophysics Data System (ADS)

    Larkin, K. E.; Gooday, A. J.; Woulds, C.; Jeffreys, R.; Schwartz, M.; Cowie, G.; Whitcraft, C.; Levin, L.; Dick, J. R.; Pond, D. W.

    2014-01-01

    Foraminifera are an important component of benthic communities in oxygen depleted settings, where they potentially play a~significant role in the processing of organic matter. We tracked the uptake of a 13C-labeled algal food source into individual fatty acids in the benthic foraminiferal species, Uvigerina ex. gr. semiornata, from the Arabian Sea oxygen minimum zone (OMZ). The tracer experiments were conducted on the Pakistan Margin during the late/post monsoon period (August-October 2003). A monoculture of the diatom Thalassiosira weisflogii was 13C-labeled and used to simulate a pulse of phytoplankton in two complementary experiments. A lander system was used for in situ incubations at 140 m and for 2.5 days duration, whilst a laboratory incubation used an oxystat system to maintain ambient dissolved oxygen concentrations. These shipboard experiments were terminated after 5 days. Uptake of diatoms was rapid, with high incorporation of diatom fatty acids into foraminifera after ~2 days in both experiments. Ingestion of the diatom food source was indicated by the increase over time in the quantity of diatom biomarker fatty acids in the foraminifera and by the high percentage of 13C in many of the fatty acids present at the endpoint of both in~situ and laboratory-based experiments. These results indicate that U. ex. gr. semiornata rapidly ingested the diatom food source and that this foraminifera will play an important role in the short-term cycling of organic matter within this OMZ environment. The experiments also suggested that U. ex. gr. semiornata consumed non-labeled bacterial food items, particularly bacteria, and synthesised the polyunsaturated fatty acid 20:4(n-6) de novo. 20:4(n-6) is often abundant in benthic fauna yet its origins and function have remained unclear. This study demonstrates that U. ex. gr. semiornata is capable of de novo synthesis of this "essential fatty acid" and is potentially a major source of this dietary nutrient in benthic food

  7. Multifunctional Hyaluronic Acid and Chondroitin Sulfate Nanoparticles: Impact of Glycosaminoglycan Presentation on Receptor Mediated Cellular Uptake and Immune Activation.

    PubMed

    Oommen, Oommen P; Duehrkop, Claudia; Nilsson, Bo; Hilborn, Jöns; Varghese, Oommen P

    2016-08-17

    Hyaluronic acid (HA) and chondroitin sulfate (CS) polymers are extensively used for various biomedical applications, such as for tissue engineering, drug delivery, and gene delivery. Although both these biopolymers are known to target cell surface CD44 receptors, their relative cellular targeting properties and immune activation potential have never been evaluated. In this article, we present the synthesis and characterization of novel self-assembled supramolecular HA and CS nanoparticles (NPs). These NPs were developed using fluorescein as a hydrophobic component that induced amphiphilicity in biopolymers and also efficiently stabilized anticancer drug doxorubicin (DOX) promoting a near zero-order drug release. The cellular uptake and cytotoxicity studies of these NPs in different human cancer lines, namely, human colorectal carcinoma cell line HCT116 and human breast cancer cell line MCF-7 demonstrated dose dependent cytotoxicity. Interestingly, both NPs showed CD44 dependent cellular uptake with the CS-DOX NP displaying higher dose-dependent cytotoxicity than the HA-DOX NP in different mammalian cells tested. Immunological evaluation of these nanocarriers in an ex vivo human whole blood model revealed that unlike unmodified polymers, the HA NP and CS NP surprisingly showed platelet aggregation and thrombin-antithrombin complex formation at high concentrations (0.8 mg/mL). We also observed a clear difference in early- and late-stage complement activation (C3a and sC5b-9) with CS and CS NP triggering significant complement activation at high concentrations (0.08-0.8 mg/mL), unlike HA and HA NP. These results offer new insight into designing glycosaminoglycan-based NPs and understanding their hematological responses and targeting ability. PMID:27468113

  8. Dust Modeling with GEOS-Chem: Evidence for Acidic Uptake on Dust Surfaces during INTEX-B

    NASA Technical Reports Server (NTRS)

    Fairlie, T. Duncan

    2007-01-01

    We use measurements of aerosol ion composition and size made from the DC8 aircraft during the 2006 INTEX-B airborne campaign to identify mineral dust signatures, and look for evidence for interaction of dust with acidic components. Coating of dust with sulfate or nitrate favors the role of dust particles as cloud condensation nucleii, can promote further uptake of SO2 and N2O5, can impact NOx/HNO3 partitioning, and can shift sulfate or nitrate towards larger sizes, affecting atmospheric lifetimes for both aerosol and gas components. Mineral dust had a pervasive presence on flights made during the Northern Pacific deployment of the INTEX-B mission. We use scatter plots of ion mixing ratios with Na+ and Ca(2+) to distinguish sea salt and mineral components of the aerosol distribution, respectively. Positive correlations of non-sea-salt sulfate and nitrate with calcium indicate that the dusty air stream is associated with polluted air masses. Sulfate-ammonium scatter plots indicate sulfate to be primarily in the form of (NH4)2SO4. A positive correlation between Ca(2+) and NO-, but little evidence of NH4NO3, suggests that NO3- may be associated with mineral dust surfaces. 3-d model simulations conducted with the GEOS-Chem chemical transport model indicate that transpacific transport from East Asia was principally responsible for the dust observed from the aircraft over the Pacific. We compare the aerosol component relationships in the model with those observed. Uptake of sulfate and nitrate on the dust is not yet represented in the model.

  9. Acidic domain in dentin phosphophoryn facilitates cellular uptake: implications in targeted protein delivery.

    PubMed

    Ravindran, Sriram; Snee, Preston T; Ramachandran, Amsaveni; George, Anne

    2013-05-31

    Dentin phosphophoryn is nature's most acidic protein found predominantly in the dentin extracellular matrix. Its unique amino acid composition containing Asp-Ser (DS)-rich repeats makes it highly anionic. It has a low isoelectric point (pI 1.1) and, therefore, tends to be negatively charged at physiological pH. Phosphophoryn is normally associated with matrix mineralization as it can bind avidly to Ca(2+). It is well known that several macromolecules present in the extracellular matrix can be internalized and localized to specific intracellular compartments. In this study we demonstrate that dentin phosphophoryn (DPP) is internalized by several cell types via a non-conventional endocytic process. Utilizing a DSS polypeptide derived from DPP, we demonstrate the repetitive DSS-rich domain facilitates that endocytosis. As a proof-of-concept, we further demonstrate the use of this polypeptide as a protein delivery vehicle by delivering the osteoblast transcription factor Runx2 to the nucleus of mesenchymal cells. The functionality of the endocytosed Runx2 protein was demonstrated by performing gene expression analysis of Runx2 target genes. Nuclear localization was also demonstrated with the fusion protein DSS-Runx2 conjugated to quantum dots in two- and three-dimensional culture models in vitro and in vivo. Overall, we demonstrate that the DSS domain of DPP functions as a novel cell-penetrating peptide, and these findings demonstrate new opportunities for intracellular delivery of therapeutic proteins and cell tracking in vivo.

  10. Isp7 is a novel regulator of amino acid uptake in the TOR signaling pathway.

    PubMed

    Laor, Dana; Cohen, Adiel; Pasmanik-Chor, Metsada; Oron-Karni, Varda; Kupiec, Martin; Weisman, Ronit

    2014-03-01

    TOR proteins reside in two distinct complexes, TOR complexes 1 and 2 (TORC1 and TORC2), that are central for the regulation of cellular growth, proliferation, and survival. TOR is also the target for the immunosuppressive and anticancer drug rapamycin. In Schizosaccharomyces pombe, disruption of the TSC complex, mutations in which can lead to the tuberous sclerosis syndrome in humans, results in a rapamycin-sensitive phenotype under poor nitrogen conditions. We show here that the sensitivity to rapamycin is mediated via inhibition of TORC1 and suppressed by overexpression of isp7(+), a member of the family of 2-oxoglutarate-Fe(II)-dependent oxygenase genes. The transcript level of isp7(+) is negatively regulated by TORC1 but positively regulated by TORC2. Yet we find extensive similarity between the transcriptome of cells disrupted for isp7(+) and cells mutated in the catalytic subunit of TORC1. Moreover, Isp7 regulates amino acid permease expression in a fashion similar to that of TORC1 and opposite that of TORC2. Overexpression of isp7(+) induces TORC1-dependent phosphorylation of ribosomal protein Rps6 while inhibiting TORC2-dependent phosphorylation and activation of the AGC-like kinase Gad8. Taken together, our findings suggest a central role for Isp7 in amino acid homeostasis and the presence of isp7(+)-dependent regulatory loops that affect both TORC1 and TORC2.

  11. Light-Activated Amino Acid Transport Systems in Halobacterium halobium Envelope Vesicles: Role of Chemical and Electrical Gradients

    NASA Technical Reports Server (NTRS)

    MacDonald, Russell E.; Greene, Richard V.; Lanyi, Janos K.

    1977-01-01

    The accumulation of 20 commonly occurring L-amino acids by cell envelope vesicles of Halobacterium halobium, in response to light-induced membrane potential and an artificially created sodium gradient, has been studied. Nineteen of these amino acids are actively accumulated under either or both of these conditions. Glutamate is unique in that its uptake is driven only by a chemical gradient for sodium. Amino acid concentrations at half-maximal uptake rates (Km) and maximal transport rates (V(sub max) have been determined for the uptake of all 19 amino acids. The transport systems have been partially characterized with respect to groups of amino acids transported by common carriers, cation effects, and relative response to the electrical and chemical components of the sodium gradient, the driving forces for uptake. The data presented clearly show that the carrier systems, which are responsible for uptake of individual amino acids, are as variable in their properties as those found in other organisms, i. e., some are highly specific for individual amino acids, some transport several amino acids competitively, some are activated by a chemical gradient of sodium only, and some function also in the complete absence of such a gradient. For all amino acids, Na(+) and K(+) are both required for maximal rate of uptake. The carriers for L-leucine and L-histidine are symmetrical in that these amino acids are transported in both directions across the vesicle membrane. It is suggested that coupling of substrate transport to metabolic energy via transient ionic gradients may be a general phenomenon in procaryotes.

  12. NI-37INCREASED CEREBRAL AMINO ACID UPTAKE DURING AND AFTER EPILEPTIC DISORDERS MIMICS BRAIN TUMOR IN 18F-FET PET

    PubMed Central

    Hutterer, Markus; Krenn, Yvonne; Kunz, Alexander; McCoy, Marc; Egger, Barbara; Schröder, Michael; Wendl, Christina; Marienhagen, Jörg; Fritsch, Brita; Urbach, Horst; Meyer, Philipp T.; Galldiks, Norbert; Langen, Karl-Josef; Hau, Peter; Trinka, Eugen

    2014-01-01

    BACKGROUND: O-(2-[F-18]fluoroethyl)-L-tyrosine (18F-FET) PET has become an important diagnostic tool in addition to standard MRI to delineate cerebral gliomas. However, 18F-FET uptake has also been observed in non-tumoral lesions. METHODS AND RESULTS: We report on abnormal non-tumoral 18F-FET uptake in 6 patients with epileptic disorders: Patients A-C with clinically stable anaplastic astrocytoma over years, Patient D with anaplastic oligodendroglioma with stable residual tumor, Patient E with initial diagnosis of glioblastoma, Patient F with subacute cerebral ischemia. All patients presented initially with repeated epileptic seizures or status epilepticus and typical clinical and EEG findings. Standard MRI (T1 + /-contrast, T2/FLAIR) showed cortical and subcortical contrast enhancement and/or T2/FLAIR signal alterations and 18F-FET PET demonstrated a significantly increased cortical amino acid uptake. 18F-FET uptake and contrast enhancement on MRI resolved completely after cessation of epileptic activity. Patient C suffered from a prolonged postictal state. In that patient, EEG monitoring demonstrated a left hemispheric deceleration without signs of epileptic discharges; additionally, 18F-FDG PET and HMPAO SPECT showed cortical glucose hypometabolism and hypoperfusion, not consistent with a status epilepticus. After 14 weeks, clinical symptoms and the cortical 18F-FET uptake resolved completely. CONCLUSION: Abnormal 18F-FET uptake may occur in patients with epileptic disorders in brain areas not infiltrated by tumor. The reason for this phenomenon is yet unknown.

  13. Coenzyme A transferase from Clostridium acetobutylicum ATCC 824 and its role in the uptake of acids

    SciTech Connect

    Wiesenborn, D.P.; Rudolph, F.B.; Papoutsakis, E.T. )

    1989-02-01

    Coenzyme A (CoA) transferase from Clostridium acetobutylicum ATCC 824 was purified 81-fold to homogeneity. This enzyme was stable in the presence of 0.5 M ammonium sulfate and 20% (vol/vol) glycerol, whereas activity was rapidly lost in the absence of these stabilizers. The kinetic binding mechanism was Ping Pong Bi Bi, and the K{sub m} values at pH 7.5 and 30{degree}C for acetate, propionate, and butyrate were, respectively, 1,200, 1,000, and 660 mM, while the K{sub m} value for acetoacetyl-CoA ranged from about 7 to 56{mu}M, depending on the acid substrate. The K{sub m} values for butyrate and acetate were high relative to the intracellular concentrations of these species; consequently, in vivo enzyme activity is expected to be sensitive to changes in those concentrations. In addition to the carboxylic acids listed above, this CoA transferase was able to convert valerate, isobutyrate, and crotonate; however, the conversion of formate, n-caproate, and isovalerate was not detected. The acetate and butyrate conversion reactions in vitro were inhibited by physiological levels of acetone and butanol, and this may be another factor in the in vivo regulation of enzyme activity. The optimum pH of acetate conversion was broad, with at least 80% of maximal activity from pH 5.9 to greater than 7.8. The purified enzyme was a heterotetramer with subunit molecular weights of about 23,000 and 25,000.

  14. Uptake of proline by the scutellum of germinating barley grain

    SciTech Connect

    Vaeisaenen, E.; Sopanen, T.

    1986-04-01

    Scutella separated from germinating grains of barley (Hordeum vulgare L. cv Himalaya) took up 1 millimolar L-(/sup 14/C)proline at an initial rate of about 6.5 micromoles gram/sup -1/ fresh weight hour/sup -1/ (pH 5, 30/sup 0/C). The uptake had a pH optimum at 5. The bulk of the uptake (93%) was via carrier-mediated active transport. All of the 19 L-amino acids tested at 10 millimolar concentration inhibited the mediated uptake of 1 millimolar proline, the inhibitions varying from 18 to 76%. By studying how large a fraction of the mediated uptake was inhibitable by asparagine, alanine, glutamine, and leucine, the mediated uptake was shown to be due to three components. Two of these are most probably attributable to the two nonspecific uptake systems proposed earlier to act in the uptake of glutamine and leucine. The third component was not inhibited by glutamine, asparagine, or alanine, but was inhibited by unlabeled proline and leucine. The uptake by this system was apparently carrier-mediated active transport. D-Proline inhibited this system as strongly as L-proline. Nine of the 16 L-amino tested at 50 millimolar concentrations did not inhibit the uptake of 1 millimolar proline by this system. Valine, leucine, isoleucine, and the basic amino acids were inhibitory, but in spite of this, they did not appear to be taken up by this system. It seems therefore that in addition to two nonspecific amino acid uptake systems the scutella have an uptake system which is specific for proline. It is likely that this proline-specific system accounts for the bulk of proline uptake in a germinating grain.

  15. An in situ optical imaging system for measuring lipid uptake, vessel contraction, and lymph flow in small animal lymphatic vessels

    NASA Astrophysics Data System (ADS)

    Kassis, Timothy; Weiler, Michael J.; Dixon, J. Brandon

    2012-03-01

    All dietary lipids are transported to venous circulation through the lymphatic system, yet the underlying mechanisms that regulate this process remain unclear. Understanding how the lymphatics functionally respond to changes in lipid load is important in the diagnosis and treatment of lipid and lymphatic related diseases such as obesity, hypercholesterolemia, and lymphedema. Therefore, we sought to develop an in situ imaging system to quantify and correlate lymphatic function as it relates to lipid transport. A custom-built optical set-up provides us with the capability of dual-channel imaging of both high-speed bright-field video and fluorescence simultaneously. This is achieved by dividing the light path into two optical bands. Utilizing high-speed and back-illuminated CCD cameras and post-acquisition image processing algorithms, we have the potential quantify correlations between vessel contraction, lymph flow and lipid concentration of mesenteric lymphatic vessels in situ. Local flow velocity is measured through lymphocyte tracking, vessel contraction through measurements of the vessel walls and lipid uptake through fluorescence intensity tracking of a fluorescent long chain fatty acid analogue, Bodipy FL C16. This system will prove to be an invaluable tool for both scientists studying lymphatic function in health and disease, and those investigating strategies for targeting the lymphatic system with orally delivered drugs.

  16. l-Methionine Placental Uptake

    PubMed Central

    Araújo, João R.; Correia-Branco, Ana; Ramalho, Carla; Gonçalves, Pedro; Pinho, Maria J.; Keating, Elisa

    2013-01-01

    Our aim was to investigate the influence of gestational diabetes mellitus (GDM) and GDM-associated conditions upon the placental uptake of 14C-l-methionine (14C-l-Met). The 14C-l-Met uptake by human trophoblasts (TBs) obtained from normal pregnancies (normal trophoblast [NTB] cells) is mainly system l-type amino acid transporter 1 (LAT1 [L])-mediated, although a small contribution of system y+LAT2 is also present. Comparison of 14C-l-Met uptake by NTB and by human TBs obtained from GDM pregnancies (diabetic trophoblast [DTB] cells) reveals similar kinetics, but a contribution of systems A, LAT2, and b0+ and a greater contribution of system y+LAT1 appears to exist in DTB cells. Short-term exposure to insulin and long-term exposure to high glucose, tumor necrosis factor-α, and leptin decrease 14C-l-Met uptake in a human TB (Bewo) cell line. The effect of leptin was dependent upon phosphoinositide 3-kinase, extracellular-signal-regulated kinase 1/2 (ERK/MEK 1/2), and p38 mitogen-activated protein kinase. In conclusion, GDM does not quantitatively alter 14C-l-Met placental uptake, although it changes the nature of transporters involved in that process. PMID:23653387

  17. Uptake of algal carbon and the likely synthesis of an "essential" fatty acid by Uvigerina ex. gr. semiornata (Foraminifera) within the Pakistan margin oxygen minimum zone: evidence from fatty acid biomarker and 13C tracer experiments

    NASA Astrophysics Data System (ADS)

    Larkin, K. E.; Gooday, A. J.; Woulds, C.; Jeffreys, R. M.; Schwartz, M.; Cowie, G.; Whitcraft, C.; Levin, L.; Dick, J. R.; Pond, D. W.

    2014-07-01

    Foraminifera are an important component of benthic communities in oxygen-depleted settings, where they potentially play a significant role in the processing of organic matter. We tracked the uptake of a 13C-labelled algal food source into individual fatty acids in the benthic foraminiferal species Uvigerina ex. gr. semiornata from the Arabian Sea oxygen minimum zone (OMZ). The tracer experiments were conducted on the Pakistan margin during the late/post monsoon period (August-October 2003). A monoculture of the diatom Thalassiosira weisflogii was 13C-labelled and used to simulate a pulse of phytoplankton in two complementary experiments. A lander system was used for in situ incubations at 140 m water depth and for 2.5 days in duration. Shipboard laboratory incubations of cores collected at 140 m incorporated an oxystat system to maintain ambient dissolved oxygen concentrations and were terminated after 5 days. Uptake of diatoms was rapid, with a high incorporation of diatom fatty acids into foraminifera after ~ 2 days in both experiments. Ingestion of the diatom food source was indicated by the increase over time in the quantity of diatom biomarker fatty acids in the foraminifera and by the high percentage of 13C in many of the fatty acids present at the endpoint of both in situ and laboratory-based experiments. These results indicate that acid" is often abundant in benthic fauna, yet

  18. Characterization of methylaminoisobutyric acid transport by system A in rat mammary gland.

    PubMed

    Tovar, A R; Avila, E; DeSantiago, S; Torres, N

    2000-07-01

    During lactation, the mammary gland has a large demand for amino acids for the synthesis of milk proteins and fatty acids. Arteriovenous differences in amino acids across the mammary gland show an elevated uptake of small neutral amino acids that are mainly transported via system A. The purpose of this study was to characterize the transport of methylaminoisobutyric acid (MeAIB), an amino acid analog used to model transport by system A in lactating rat mammary gland explants. MeAIB accumulation in mammary gland cells increased steadily, and after 3 hours of incubation, the intracellular concentration of the analog was 8-fold higher than the concentration in the medium. MeAIB transport into mammary gland explants showed a Km of 3.3 +/- 0.4 mmol/L and a maximal velocity (Vmax) of 555 +/- 23 pmol/microL intracellular fluid (ICF) x min, indicating a system with high capacity but low affinity for its substrate. MeAIB transport into mammary tissue depended highly on Na+, and the uptake was inhibited by addition of natural and analog small neutral amino acids. Cationic, anionic, and large neutral amino acids did not reduce MeAIB transport into mammary gland explants. Preincubation of mammary gland explants in an amino acid-free medium stimulated MeAIB transport, suggesting an adaptive regulation. The addition of an equimolar mixture of alanine, glycine, and serine to the preincubation medium inhibited stimulation of MeAIB transport. Furthermore, stimulation of MeAIB uptake by amino acid starvation was also prevented by the addition of actinomycin D, cycloheximide, tunicamycin, and colchicine. Dibutyryl cyclic adenosine monophosphate (cAMP) increased MeAIB uptake, whereas phorbol 12-myristate 13-acetate (PMA) did not stimulate MeAIB transport. During the first postweaning days, kinetic analyses showed a decrease of 27% in the Vmax. Injection of rat lactating mammary gland mRNA into Xenopus laevis oocytes induced expression of the MeAIB transport system; however, the

  19. L-FABP T94A decreased fatty acid uptake and altered hepatic triglyceride and cholesterol accumulation in Chang liver cells stably transfected with L-FABP.

    PubMed

    Gao, Na; Qu, Xia; Yan, Jin; Huang, Qi; Yuan, Hao-Yong; Ouyang, Dong-Sheng

    2010-12-01

    Liver fatty acid-binding protein (L-FABP, FABP1) is a highly conserved key factor in lipid metabolism. This study was undertaken to verify whether the T94A mutation in the L-FABP gene affects fatty acid uptake and intracellular esterification into specific lipid pools. Candidate SNPs were recreated using site-directed mutagenesis and tested for physical function in stably transfected Chang liver cell lines. We found that the T94A mutant of L-FABP lowered FFA uptake but had no effect on FFA efflux. L-FABP T94A-expressing cells showed decreased triglyceride content and increased cholesterol accumulation compared to the wild-type control for cells incubated with an FFA mixture (oleate: palmitate, 2:1 ratio). In conclusion, our study provided additional indications of the functional relevance of the L-FABP T94A SNP in hepatic fatty acid and lipid metabolism in humans.

  20. Laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance

    NASA Astrophysics Data System (ADS)

    Thornberry, T.; Gierczak, T.; Gao, R. S.; Vömel, H.; Watts, L. A.; Burkholder, J. B.; Fahey, D. W.

    2011-02-01

    Chilled mirror hygrometers (CMH) are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios (<5 ppm) in the upper troposphere and lower stratosphere (UT/LS). Understanding the source of the measurement discrepancies is important for a more accurate and reliable determination of water vapour abundance in this region. We have conducted a laboratory study to investigate the potential interference of gas-phase nitric acid (HNO3) with the measurement of frost point temperature, and consequently the water vapour mixing ratio, determined by CMH under conditions representative of operation in the UT/LS. No detectable interference in the measured frost point temperature was found for HNO3 mixing ratios of up to 4 ppb for exposure times up to 150 min. HNO3 was observed to co-condense on the mirror frost, with the adsorbed mass increasing linearly with time at constant exposure levels. Over the duration of a typical balloon sonde ascent (90-120 min), the maximum accumulated HNO3 amounts were comparable to monolayer coverage of the geometric mirror surface area, which corresponds to only a small fraction of the actual frost layer surface area. This small amount of co-condensed HNO3 is consistent with the observed lack of HNO3 interference in the frost point measurement because the CMH utilizes significant reductions (>10%) in surface reflectivity by the condensate to determine H2O.

  1. Laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance

    NASA Astrophysics Data System (ADS)

    Thornberry, T.; Gierczak, T.; Gao, R. S.; Vömel, H.; Watts, L. A.; Burkholder, J. B.; Fahey, D. W.

    2010-08-01

    Chilled mirror hygrometers (CMH) are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios (<5 ppm) in the upper troposphere and lower stratosphere (UT/LS). Understanding the source of the measurement discrepancies is important for a more accurate and reliable determination of water vapour abundance in this region. We have conducted a laboratory study to investigate the potential interference of gas-phase nitric acid (HNO3) with the measurement of frost point temperature, and consequently the water vapour mixing ratio, determined by CMH under conditions representative of operation in the UT/LS. No detectable interference in the measured frost point temperature was found for HNO3 mixing ratios of up to 4 ppb for exposure times up to 150 min. HNO3 was observed to co-condense on the mirror frost, with the adsorbed mass increasing linearly with time at constant exposure levels. Over the duration of a typical balloon sonde ascent (90-120 min), the maximum accumulated HNO3 amounts were comparable to monolayer coverage of the geometric mirror surface area, which corresponds to only a small fraction of the actual frost layer surface area. This small amount of co-condensed HNO3 is consistent with the observed lack of HNO3 interference in the frost point measurement because the CMH utilizes significant reductions (>10%) in surface reflectivity by the condensate to determine H2O.

  2. Linkage between postabsorptive amino acid release and glutamate uptake in skeletal muscle tissue of healthy young subjects, cancer patients, and the elderly.

    PubMed

    Holm, E; Hack, V; Tokus, M; Breitkreutz, R; Babylon, A; Dröge, W

    1997-06-01

    Several diseases of varying etiology that are commonly associated with the loss of skeletal muscle mass were found to be associated with a decrease in muscular glutamate and glutathione levels and in glutamate uptake in the postabsorptive state. In view of the Na+ dependency and insulin responsiveness of glutamate transport we studied the postabsorptive glutamate exchange in more detail. Our study demonstrates a linkage between glutamate uptake and the export of other amino acids, suggesting that protein catabolism and the resulting coexport of amino acids plus Na+ substitute for insulin as a driving force for the Na+ gradient in the postabsorptive state. The regression function of the correlation between relative glutamate exchange and cumulative amino acid exchange in cancer patients was lower than that in non-tumor-bearing subjects, suggesting that cancer patients must release more amino acids to achieve the same glutamate uptake. In addition, cancer patients had a lower average cumulative amino acid exchange rate than non-tumor-bearing subjects, suggesting that the abnormally low relative glutamate exchange capacity of cancer patients results mainly from inadequate postabsorptive protein catabolism in the skeletal muscle tissue. Both cancer patients and non-tumor-bearing elderly subjects had higher arterial glutamate levels and alanine release than young subjects, indicative of a substantial glycolytic activity in the skeletal muscle. However, elderly non-tumor-bearing subjects showed, in contrast to cancer patients, in the postabsorptive state a stronger cumulative amino acid release and postabsorptive glutamate uptake than healthy young subjects. These changes are discussed in view of the age-related loss of skeletal muscle mass.

  3. Impaired uptake of conjugated bile acids and hepatitis b virus pres1-binding in na+-taurocholate cotransporting polypeptide knockout mice

    PubMed Central

    Slijepcevic, Davor; Kaufman, Christina; Wichers, Catharina GK; Gilglioni, Eduardo H; Lempp, Florian A; Duijst, Suzanne; de Waart, Dirk R; Oude Elferink, Ronald PJ; Mier, Walter; Stieger, Bruno; Beuers, Ulrich; Urban, Stephan; van de Graaf, Stan FJ

    2015-01-01

    The Na+-taurocholate cotransporting polypeptide (NTCP) mediates uptake of conjugated bile acids (BAs) and is localized at the basolateral membrane of hepatocytes. It has recently been recognized as the receptor mediating hepatocyte-specific entry of hepatitis B virus and hepatitis delta virus. Myrcludex B, a peptide inhibitor of hepatitis B virus entry, is assumed to specifically target NTCP. Here, we investigated BA transport and Myrcludex B binding in the first Slc10a1-knockout mouse model (Slc10a1 encodes NTCP). Primary Slc10a1−/− hepatocytes showed absence of sodium-dependent taurocholic acid uptake, whereas sodium-independent taurocholic acid uptake was unchanged. In vivo, this was manifested as a decreased serum BA clearance in all knockout mice. In a subset of mice, NTCP deficiency resulted in markedly elevated total serum BA concentrations, mainly composed of conjugated BAs. The hypercholanemic phenotype was rapidly triggered by a diet supplemented with ursodeoxycholic acid. Biliary BA output remained intact, while fecal BA excretion was reduced in hypercholanemic Slc10a1−/− mice, explained by increased Asbt and Ostα/β expression. These mice further showed reduced Asbt expression in the kidney and increased renal BA excretion. Hepatic uptake of conjugated BAs was potentially affected by down-regulation of OATP1A1 and up-regulation of OATP1A4. Furthermore, sodium-dependent taurocholic acid uptake was inhibited by Myrcludex B in wild-type hepatocytes, while Slc10a1−/− hepatocytes were insensitive to Myrcludex B. Finally, positron emission tomography showed a complete abrogation of hepatic binding of labeled Myrcludex B in Slc10a1-/- mice. Conclusion: The Slc10a1-knockout mouse model supports the central role of NTCP in hepatic uptake of conjugated BAs and hepatitis B virus preS1/Myrcludex B binding in vivo; the NTCP-independent hepatic BA uptake machinery maintains a (slower) enterohepatic circulation of BAs, although it is occasionally

  4. Spatiotemporal variation of nitrate uptake kinetics within the maize (Zea mays L.) root system is associated with greater nitrate uptake and interactions with architectural phenes.

    PubMed

    York, Larry M; Silberbush, Moshe; Lynch, Jonathan P

    2016-06-01

    Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal.

  5. Spatiotemporal variation of nitrate uptake kinetics within the maize (Zea mays L.) root system is associated with greater nitrate uptake and interactions with architectural phenes.

    PubMed

    York, Larry M; Silberbush, Moshe; Lynch, Jonathan P

    2016-06-01

    Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal. PMID:27037741

  6. Fluorinated Peptide Nucleic Acids with Fluoroacetyl Side Chain Bearing 5-(F/CF3)-Uracil: Synthesis and Cell Uptake Studies.

    PubMed

    Ellipilli, Satheesh; Palvai, Sandeep; Ganesh, Krishna N

    2016-08-01

    Fluorine incorporation into organic molecules imparts favorable physicochemical properties such as lipophilicity, solubility and metabolic stability necessary for drug action. Toward such applications using peptide nucleic acids (PNA), we herein report the chemical synthesis of fluorinated PNA monomers and biophysical studies of derived PNA oligomers containing fluorine in in the acetyl side chain (-CHF-CO-) bearing nucleobase uracil (5-F/5-CF3-U). The crystal structures of fluorinated racemic PNA monomers reveal interesting base pairing of enantiomers and packing arrangements directed by the chiral F substituent. Reverse phase HPLC show higher hydrophobicity of fluorinated PNA oligomers, dependent on the number and site of the fluorine substitution: fluorine on carbon adjacent to the carbonyl group induces higher lipophilicity than fluorine on nucleobase or in the backbone. The PNA oligomers containing fluorinated bases form hybrids with cDNA/RNA with slightly lower stability compared to that of unmodified aeg PNA, perhaps due to electronic effects. The uptake of fluorinated homooligomeric PNAs by HeLa cells was as facile as that of nonfluorinated PNA. In conjunction with our previous work on PNAs fluorinated in backbone and at N-terminus, it is evident that the fluorinated PNAs have potential to emerge as a new class of PNA analogues for applications in functional inhibition of RNA. PMID:27391099

  7. Effects of Exogenous Gibberellic Acid3 on Iron and Manganese Plaque Amounts and Iron and Manganese Uptake in Rice

    PubMed Central

    Guo, Yue; Zhu, Changhua; Gan, Lijun; Ng, Denny; Xia, Kai

    2015-01-01

    Gibberellins (GA) regulate various components of plant development. Iron and Mn plaque result from oxiding and hydroxiding Fe and Mn, respectively, on the roots of aquatic plant species such as rice (Oryza sativa L.). In this study, we found that exogenous gibberellic acid3 (GA3) spray decreased Fe plaque, but increased Mn plaque, with applications of Kimura B nutrient solution. Similar effects from GA3, leading to reduced Fe plaque and increased Mn plaque, were also found by scanning electron microscopy and energy dispersive X-ray spectrometric microanalysis. Reduced Fe plaque was observed after applying GA3 to the groups containing added Fe2+ (17 and 42 mg•L-1) and an increasing trend was detected in Mn plaques of the Mn2+ (34 and 84 mg•L-1) added treatments. In contrast, an inhibitor of GA3, uniconazole, reversed the effects of GA3. The uptake of Fe or Mn in rice plants was enhanced after GA3 application and Fe or Mn plaque production. Strong synergetic effects of GA3 application on Fe plaque production were detected. However, no synergetic effects on Mn plaque production were detected. PMID:25710173

  8. Technetium-99m (v) dimercaptosuccinic acid uptake in patients with head and neck squamous carcinoma: Experience in imaging

    SciTech Connect

    Watkinson, J.C.; Lazarus, C.R.; Mistry, R.; Shaheen, O.H.; Maisey, M.N.; Clarke, S.E.

    1989-02-01

    A recently developed imaging agent, technetium-99m (v) dimercaptosuccinic acid (/sup 99m/Tc (v) DMSA), has been used to assess head and neck squamous carcinoma (SCC). We have prospectively studied 62 patients of whom 53 had a histologically proven head and neck SCC. The remaining nine had benign lesions. The results of planar imaging in patients with primary disease yielded an 85% sensitivity and 78% specificity. Planar imaging in patients with cervical lymphadenopathy revealed a 59% sensitivity. Nineteen patients also had single photon emission computed tomography imaging which improved the image quality, spatial resolution and sensitivity of the investigation. Twenty-seven patients were scanned before and after radiotherapy and, of these, 96% showed positive uptake in the salivary glands with no evidence of tumor recurrence. This study has shown /sup 99m/Tc (v) DMSA imaging provides a cheap and rapid method of investigating head and neck SCC and further studies are necessary to evaluate its role in the management of patients with this disease.

  9. Biodegradable chelating agent ethylenediaminedisuccinic acid reduces uptake of copper through alleviation of copper toxicity in hydroponically grown Chrysanthemum coronarium L.

    PubMed

    Wei, Lan; Luo, Chunling; Wang, Chunchun; Li, Xiangdong; Shen, Zhenguo

    2007-04-01

    Hydroponic cultures were conducted to investigate the effects of the biodegradable chelating agent S,S-ethylenediaminedisuccinic acid (EDDS) on the growth and copper uptake by garland chrysanthemum (Chrysanthemum coronarium L.), a plant species sensitive to soil chelate amendment. In the presence of 50 micromol/L Cu, the addition of EDDS increased shoot and root biomass and the vitality of cells in root tips and decreased the relative electrolyte leakage of root cells and the concentration of Cu in shoots. When the roots were pretreated with 65 degrees C hot water for 0.5 to 2 h or with 0.001 to 0.1 mol/L HCl for 24 h before the exposure to 50 micromol/L Cu + 100 micromol/L EDDS, the concentration of Cu in shoots increased considerably compared with the plants without any pretreatment. A statistically significant correlation was found between the Cu concentrations in shoots and the relative electrolyte leakage of root cells. These results indicated that Cu-EDDS might be a less bioavailable form to plants and that some physiological damage to the roots led to enhanced accumulation of Cu in plant shoots.

  10. Influence of swine manure on growth, P uptake and activities of acid phosphatase and phytase of Polygonum hydropiper.

    PubMed

    Ye, Daihua; Li, Tingxuan; Chen, Guangdeng; Zheng, Zicheng; Yu, Haiying; Zhang, Xizhou

    2014-06-01

    Excessive application of animal manure to the farmland results in enrichment of P in the soil. Phytoremediation is a promising strategy for extracting excess P from manure impacted soil. P uptake characteristics of a mining ecotype (ME) and a non-mining ecotype (NME) of Polygonum hydropiper were investigated in this study by adopting soil culture containing various concentrations of swine manure (0-200 g swine manure kg(-1) soil). A peak value in the biomass of P. hydropiper was determined in 100 g kg(-1) soil. Significant increase of P content in tissues of two ecotypes was noticed with an increase in swine manure concentration. Maximum P accumulation in shoots and roots was observed at the concentration of 100 g kg(-1) soil, however, the ME accumulated more P as compared to the NME. The ME showed a lower plant effective number and a higher P extraction ratio compared to the NME. Both acid phosphatase and phytase activities of P. hydropiper were obviously enhanced under swine manure impacted soil compared with control, while those of ME higher than the NMEs. Therefore, the two ecotypes of P. hydropiper can accumulate P from soil amended with swine manure and establishes the foundation for phytoremediation.

  11. Dual-channel in-situ optical imaging system for quantifying lipid uptake and lymphatic pump function

    NASA Astrophysics Data System (ADS)

    Kassis, Timothy; Kohan, Alison B.; Weiler, Michael J.; Nipper, Matthew E.; Cornelius, Rachel; Tso, Patrick; Brandon Dixon, J.

    2012-08-01

    Nearly all dietary lipids are transported from the intestine to venous circulation through the lymphatic system, yet the mechanisms that regulate this process remain unclear. Elucidating the mechanisms involved in the functional response of lymphatics to changes in lipid load would provide valuable insight into recent implications of lymphatic dysfunction in lipid related diseases. Therefore, we sought to develop an in situ imaging system to quantify and correlate lymphatic function as it relates to lipid transport. The imaging platform provides the capability of dual-channel imaging of both high-speed bright-field video and fluorescence simultaneously. Utilizing post-acquisition image processing algorithms, we can quantify correlations between vessel pump function, lymph flow, and lipid concentration of mesenteric lymphatic vessels in situ. All image analysis is automated with customized LabVIEW virtual instruments; local flow is measured through lymphocyte velocity tracking, vessel contraction through measurements of the vessel wall displacement, and lipid uptake through fluorescence intensity tracking of an orally administered fluorescently labelled fatty acid analogue, BODIPY FL C16. This system will prove to be an invaluable tool for scientists studying intestinal lymphatic function in health and disease, and those investigating strategies for targeting the lymphatics with orally delivered drugs to avoid first pass metabolism.

  12. Dual-channel in-situ optical imaging system for quantifying lipid uptake and lymphatic pump function

    PubMed Central

    Kassis, Timothy; Kohan, Alison B.; Weiler, Michael J.; Nipper, Matthew E.; Cornelius, Rachel; Tso, Patrick

    2012-01-01

    Abstract. Nearly all dietary lipids are transported from the intestine to venous circulation through the lymphatic system, yet the mechanisms that regulate this process remain unclear. Elucidating the mechanisms involved in the functional response of lymphatics to changes in lipid load would provide valuable insight into recent implications of lymphatic dysfunction in lipid related diseases. Therefore, we sought to develop an in situ imaging system to quantify and correlate lymphatic function as it relates to lipid transport. The imaging platform provides the capability of dual-channel imaging of both high-speed bright-field video and fluorescence simultaneously. Utilizing post-acquisition image processing algorithms, we can quantify correlations between vessel pump function, lymph flow, and lipid concentration of mesenteric lymphatic vessels in situ. All image analysis is automated with customized LabVIEW virtual instruments; local flow is measured through lymphocyte velocity tracking, vessel contraction through measurements of the vessel wall displacement, and lipid uptake through fluorescence intensity tracking of an orally administered fluorescently labelled fatty acid analogue, BODIPY FL C16. This system will prove to be an invaluable tool for scientists studying intestinal lymphatic function in health and disease, and those investigating strategies for targeting the lymphatics with orally delivered drugs to avoid first pass metabolism. PMID:23224192

  13. In vitro release characteristics and cellular uptake of poly(D,L-lactic-co-glycolic acid) nanoparticles for topical delivery of antisense oligodeoxynucleotides.

    PubMed

    Chen, Ying-Shan; Alany, Raid G; Young, Simon A; Green, Colin R; Rupenthal, Ilva D

    2011-01-01

    The efficacy of antisense oligodeoxynucleotides (AsODNs) is compromised by their poor stability in biological fluids and the inefficient cellular uptake due to their size and negative charge. Since chemical modifications of these molecules have resulted in a number of non-antisense activities, incorporation into particulate delivery systems has offered a promising alternative. The aim of this study was to evaluate various poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles for AsODN entrapment and delivery. PLGA nanoparticles were prepared using the double emulsion solvent evaporation method. The influence of formulation parameters such as PLGA concentration and volume ratio of internal aqueous phase volume (Va1) to organic phase volume (Vo) to external aqueous phase volume (Va2) on particle size, polydispersity index (PDI) and zeta potential (ZP) was investigated using a full factorial study. The particle size increased with increasing PLGA concentrations and volume ratios, with an interaction detectable between the two factors. AsODN entrapment efficiencies ranged between 49.97% and 54.95% with no significant difference between various formulations. By fitting the in vitro release profiles to a dual first order release model it was shown that the AsODN release occurred via two processes: a diffusion controlled process in the early phase (25 to 32% within one day) and a PLGA degradation process in the latter (39 to 70% after 14 days). Cellular uptake studies using primary corneal epithelial cells suggested active transport of nanoparticles via endocytosis. PLGA nanoparticles therefore show potential to successfully entrap AsODNs, transport them into cells and release them over time due to polymer erosion.

  14. Enhanced GLT-1 mediated glutamate uptake and migration of primary astrocytes directed by fibronectin-coated electrospun poly-L-lactic acid fibers

    PubMed Central

    Zuidema, Jonathan M.; Hyzinski-García, María C.; Vlasselaer, Kristien Van; Zaccor, Nicholas; Plopper, George E.; Mongin, Alexander A.; Gilbert, Ryan J.

    2014-01-01

    Bioengineered fiber substrates are increasingly studied as a means to promote regeneration and remodeling in the injured central nervous system (CNS). Previous reports largely focused on the ability of oriented scaffolds to bridge injured regions and direct outgrowth of axonal projections. In the present work, we explored the effects of electrospun microfibers on the migration and physiological properties of brain astroglial cells. Primary rat astrocytes were cultured on either fibronectin-coated poly-l-lactic acid (PLLA) films, fibronectin-coated randomly oriented PLLA electrospun fibers, or fibronectin-coated aligned PLLA electrospun fibers. Aligned PLLA fibers strongly altered astrocytic morphology, orienting cell processes, actin microfilaments, and microtubules along the length of the fibers. On aligned fibers, astrocytes also significantly increased their migration rates in the direction of fiber orientation. We further investigated if fiber topography modifies astrocytic neuroprotective properties, namely glutamate and glutamine transport and metabolism. This was done by quantifying changes in mRNA expression (qRT-PCR) and protein levels (Western blotting) for a battery of relevant biomolecules. Interestingly, we found that cells grown on random and/or aligned fibers increased the expression levels of two glutamate transporters, GLAST and GLT-1, and an important metabolic enzyme, glutamine synthetase, as compared to the fibronectin-coated films. Functional assays revealed increases in glutamate transport rates due to GLT-1 mediated uptake, which was largely determined by the dihydrokainate-sensitive GLT-1. Overall, this study suggests that aligned PLLA fibers can promote directed astrocytic migration, and, of most importance, our in vitro results indicate for the first time that electrospun PLLA fibers can positively modify neuroprotective properties of glial cells by increasing rates of glutamate uptake. PMID:24246642

  15. Uptake of perfluorooctanoic acid, perfluorooctane sulfonate and perfluorooctane sulfonamide by carrot and lettuce from compost amended soil.

    PubMed

    Bizkarguenaga, E; Zabaleta, I; Mijangos, L; Iparraguirre, A; Fernández, L A; Prieto, A; Zuloaga, O

    2016-11-15

    Sewage sludge, which acts like a sink for many pollutants, including metals, pathogens and organic pollutants, that are not completely removed in waste water treatment plants (WWTPs), is applied as a nutrient rich organic fertilizer in many agricultural applications. In the present work, carrot and lettuce crops were grown in two different compost amended soils fortified with perfluorooctanoic acid (PFOA), perfluorosulfonate acid (PFOS) and perfluorosulfonamide (FOSA) and cultivated in a greenhouse. The plants were harvested and divided into root core, root peel and leaves in the case of carrots and into heart and leaves for lettuces. Concentrations for all the different compartments were determined to assess the bioconcentration factors (BCFs) and the plant distribution of the target analytes. The highest carrot BCFs for PFOA and PFOS were determined in the leaves (0.6-3.4), while lower values were calculated in the core (0.05-0.6) and the peel (0.05-1.9) compartments. However, PFOA was taken up in the translocation stream and accumulated more than PFOS in the edible part of lettuce. FOSA was totally degraded in the presence of carrot; however, a lower FOSA degradation was observed in presence of the lettuce, which was dependent on the total organic carbon (TOC) content of the soil. The higher the TOC value, the higher the FOSA degradation observed. No degradation was observed in the crop absence. In the case of the carrot experiments, different polymeric materials (polyethersulfone, PES, polyoxymethylene, and silicone rod) were tested to predict the concentration in the cultivation media. A high correlation (r(2)>0.63) was observed for the BCFs in the PES and in the carrot core and peel for PFOA and PFOS. It could be, concluded that the PES can be used as a first approach for the determination of the uptake of compounds such as PFOS and PFOA in carrot. PMID:27450950

  16. Uptake and metabolism of (11-/sup 3/H) all-trans retinoic acid by rabbit tracheal epithelial cells

    SciTech Connect

    Bhat, P.V.; Jetten, A.M.

    1986-01-01

    Retinoic acid (RA) inhibits squamous cell differentiation of rabbit tracheal epithelial cells in culture at concentrations as low as 10/sup -9/ - 10/sup -10/ M. These cells take up 11-(/sup 3/H)-RA readily when added to the cells either as free RA or as RA complexed to serum retinol binding protein (SRBP) or albumin. The uptake of RA by RTE cells as SRBP or albumin complexes was significantly lower than that of free RA. Metabolites were analyzed by high pressure liquid chromatography. This analysis showed that RTE cells metabolized RA to polar metabolites (Peak I) and to a less polar metabolite (Peak III). The metabolite in Peak III constituted 13-20% of the cell-associated radioactivity after 24 hrs. incubation with RA. Formation of the Peak I and Peak III metabolites from RA was observed both in undifferentiated as well as in cells that underwent terminal differentiation to squamous cells and their synthesis appeared constitutive. When cells were treated for 6 hrs with /sup 3/H-RA and then further in the absence of RA 75% of the cell-associated radioactivity was released in the medium within 24 hrs, thereafter the release was slow. Analysis of the metabolites secreted by the cells into the medium showed only the presence of Peak I metabolites. The authors data show that RTE cells metabolize RA into polar metabolites which are rapidly released into the medium and into a less polar metabolite, possibly an ester of retinoic acid, which is retained by the cell.

  17. Root-Uptake of C-14 Acetic Acid by Various Plants and C-14 Dynamics Surrounding the Experimental Tessera

    SciTech Connect

    Ogiyama, S.; Takeda, H.; Uchida, S.; Suzuki, H.; Inubushi, K.

    2008-07-01

    Carbon-14 (C-14, t{sub 1/2} = 5.73x10{sup 3} yrs) from radioactive waste is one of the most important radioactive nuclides for environmental assessment in the context of geological disposal, and understanding the transfer of radioactive elements to plants is essential for public health safety. In order to obtain fundamental knowledge, culture experiments using marigold (Tagetes patula L.), tall fescue (Festuca arundinacea S.), paddy rice (Oryza sativa L.), radish (Raphanus sativus L.), and carrot (Daucus carota L.) plants were conducted to examine root-uptake and dynamics of C-14 in the laboratory. The C-14 radioactivity in each plant part (e.g. shoot, root, edible part, etc.), medium (e.g. culture solution, sand, etc.), and air was determined. The distribution of C-14 in the plants was visualized using autoradiography. For a comparison, autoradiography was also done using Na-22. Results of the present study indicated that C-14 labeled CO{sub 2} gas was released from the culture solution to the atmosphere. Clear autoradiography images were observed in plants for the shoots and lower roots which were soaked in the culture solution. The upper roots which were not soaked in the culture solution were not clearly imaged. In the radiotracer experiment using Na-22, a clear image was observed for the whole carrot seedling, even including the upper root, on the autoradiography. However, the amounts of C-14 acetic acid absorbed by all the plants through their roots were considered to be very small. Inorganic carbon transformed from C-14 acetic acid would be taken up by plants through the roots, and some fraction of C-14 would be assimilated into the shoots by photosynthesis. (authors)

  18. Uptake and bioavailability of anthocyanins and phenolic acids from grape/blueberry juice and smoothie in vitro and in vivo.

    PubMed

    Kuntz, Sabine; Rudloff, Silvia; Asseburg, Heike; Borsch, Christian; Fröhling, Bettina; Unger, Franziska; Dold, Sebastian; Spengler, Bernhard; Römpp, Andreas; Kunz, Clemens

    2015-04-14

    The goal of eating five servings of fruits and vegetables a day has not yet been achieved. The intake of polyphenols such as anthocyanins (ACN) could be improved by consuming smoothies and juices that are increasingly popular, especially in children; however, bioavailability data concerning food matrix effects are scarce. Thus, we conducted a randomised, cross-over, bioavailability study (n 10) to determine the bioavailability of ACN and their metabolites from an ACN-rich grape/blueberry juice (841 mg ACN/litre) and smoothie (983 mg ACN/litre) in vivo, and the uptake of a corresponding grape/blueberry extract in vitro. After the intake of beverage (0·33 litres), plasma and fractionated urine samples were collected and analysed by ultra-performance liquid chromatography coupled to MS. The most abundant ACN found in plasma and urine were malvidin and peonidin as native ACN and as glucuronidated metabolites as well as 3,4-dihydroxybenzoic acid (3,4-DHB); minor ACN (delphinidin, cyanidin and petunidin) were only detected as native glycosides. Plasma pharmacokinetics and recoveries of urinary metabolites of ACN were not different for juice or smoothie intake; however, the phenolic acid 3,4-DHB was significantly better bioavailable from juice in comparison to smoothie. In vitro data with absorptive intestinal cells indicated that despite their weak chemical stability, ACN and 3,4-DHB could be detected at the basal side in their native forms. Whether smoothies as well as juices should be recommended to increase the intake of potentially health-promoting ACN and other polyphenols requires the consideration of other ingredients such as their relatively high sugar content.

  19. Uptake and release of [3H]gamma-aminobutyric acid by embryonic spinal cord neurons in dissociated cell culture

    PubMed Central

    1979-01-01

    We have investigated the uptake and release of [3H]gamma-aminobutyric acid (GABA) by embryonic chick spinal cord cells maintained in culture. Cells dissociated from 4- or 7-d-old embryos were studied between 1 and 3 wk after plating. At 3 degrees C, [3H]GABA was accumulated by a high affinity (Km approximately equal to 4 microM) and a low affinity (Km approximately equal to 100 microM) mechanism. The high affinity transport was markedly inhibited in low Na+ media, by ouabain, at 0 degrees C, and by 2,4-diaminobutyric acid. Autoradiography, after incubation in 0.1 microM [3H]GABA, showed that approximately 50% (range = 30-70%) of the multipolar cells were labeled. These cells were neurons rather than glia; action potentials and/or synaptic potentials were recorded in cells subsequently found to be labeled. Non-neuronal, fibroblast-like cells and co-cultured myotubes were not labeled under the same conditions. The fact that not all of the neurons were labeled is consistent with the suggestion, based on studies of intact adult tissue, that high affinity transport of [3H]GABA may be unique to neurons that use GABA as a neurotransmitter. Our finding that none of fifteen physiologically identified cholinergic neurons, i.e., cells that innervated nearby myotubes, were heavily labeled after incubation in 0.1 microM [3H]GABA is significant in this regard. The newly taken up [3H]GABA was not metabolized in the short run. It was stored in a form that could be released when the neurons were depolarized in a high K+ (100 mM) medium. As expected for a neurotransmitter, the K+-evoked release was reversibly inhibited by reducing the extracellular Ca++/Mg++ ratio. PMID:457763

  20. Specificity of Octopine Uptake by Rhizobium and Pseudomonas Strains

    PubMed Central

    Bergeron, Janique; MacLeod, Robert A.; Dion, Patrice

    1990-01-01

    The octopine-utilizing strain Agrobacterium tumefaciens B6S3 and three nonagrobacteria which had the capacity to utilize this opine were compared for octopine uptake. The characteristics of uptake by Rhizobium meliloti A3 and strain B6S3 were similar. In both bacteria, uptake activity was inducible by octopine and by the related opine octopinic acid, and competition assays showed that these two opine substrates were accepted by the same uptake system with an equivalent affinity. Cells of Pseudomonas putida 203 accumulated octopine against a concentration gradient, and this activity was induced specifically by octopine. While strain 203 did not utilize octopinic acid, a spontaneous mutant with a combined capacity for octopine and octopinic acid utilization was obtained. Both opines induced octopine uptake by this mutant, but octopinic acid was not a substrate for the induced system. Thus, the Pseudomonas uptake system exhibited a different specificity for octopine than the corresponding Agrobacterium system. The nonfluorescent pseudomonad GU187j, which utilized the three related opines octopine, octopinic acid, and nopaline, was constitutive for octopine uptake. Strain GU187j possessed a system which accepted these three opines, but not arginine or ornithine, with a similar affinity. PMID:16348194

  1. Composite system mediates two-step DNA uptake into Helicobacter pylori

    PubMed Central

    Stingl, Kerstin; Müller, Stephanie; Scheidgen-Kleyboldt, Gerda; Clausen, Martin; Maier, Berenike

    2009-01-01

    The Gram-negative gastric pathogen Helicobacter pylori depends on natural transformation for genomic plasticity, which leads to host adaptation and spread of resistances. Here, we show that H. pylori takes up covalently labeled fluorescent DNA preferentially at the cell poles and that uptake is dependent on the type IV secretion system ComB. By titration of external pH and detection of accessibility of the fluorophor by protons, we localized imported fluorescent DNA in the periplasm. Single molecule analysis revealed that outer membrane DNA transport occurred at a velocity of 1.3 kbp·s−1 and that previously imported DNA was reversibly extracted from the bacterium at pulling forces exceeding 23 pN. Thus, transport velocities were 10-fold higher than in Bacillus subtilis, and stalling forces were substantially lower. dsDNA stained with the intercalator YOYO-1 was transiently detected in the periplasm in wild-type H. pylori but was periplasmatically trapped in a mutant lacking the B. subtilis membrane-channel homolog ComEC. We conclude that H. pylori uses a two-step DNA uptake mechanism in which ComB transports dsDNA across the outer membrane at low force and poor specificity for DNA structure. Subsequently, Hp-ComEC mediates transport into the cytoplasm, leading to the release of the noncovalently bound DNA dye. Our findings fill the gap to propose a model for composite DNA uptake machineries in competent bacteria, all comprising the conserved ComEC channel for cytoplasmic membrane transport in combination with various transporters for access of external DNA to the cytoplasmic membrane. PMID:20080542

  2. Thyroid metabolism in the recessive sex-linked dwarf female chicken. 5. Effects of exogenous thyroid hormones on amino acid uptake by eggs.

    PubMed

    Grandhi, R R; Brown, R G; Reinhart, B S; Summers, J D

    1975-03-01

    The incorporation of L-methionine-3H(G) and L-lysine-4,5'3H(n) into egg albumen by dwarf and non-dwarf White Leghorn hens was studied together with the influence of exogenous triiodothyronine (T3) and tetraiodothyronine (T4) on those incorporation patterns. The results were influenced by the amino acid studied and by the strain of bird. The maximum uptake of methionine was a day 1 for the normal and at day 4 for the dwarf which suggested that the dwarf was storing methionine in the tissue first before incorporation into albumen. If the birds were given T3 the maximum for the normal was at day 1 and day 3 for the dwarfs. When T4 was given the maximum uptake was found at day 5 for normals, and at day 2 for dwarfs. In the dwarf, T4 administration essentially corrected the decreased rate uptake of methionine but markedly retarded its uptake by the normal birds. The results for lysine were quite different. The maximum uptake was on day 4 in control, day 3 for T3-treated and day 1 for T4-treated, normal birds. In dwarf birds, the maximum was at day 2 for the control and T4-treated, and day 4 for T3-treated groups. The data were interpreted to suggest strain differences in amino acid uptake patterns due to different rates of synthesis or composition of egg albumen and marked differences in response or recptor sites to thyroid hormones.

  3. Uptake and Reactions of Formaldehyde, Acetaldehyde, Acetone, Propanal and Ethanol in Sulfuric Acid solutions at 200-240 K: Implications for upper tropospheric aerosol composition

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Williams, M. B.; Axson, J.; Michelsen, R.

    2007-12-01

    The production of light absorbing, organic material in aerosol that is normally considered to be transparent in the UV and visible wavelength regions has significant implications for biogeochemical cycling and climate modelling. Production mechanisms likely involve carbonyl compounds such as formaldehyde, acetone, acetaldehyde and propanal that are present in significant quantities in the upper troposphere (UT). In this study, we have performed experiments focusing on a class of acid catalyzed carbonyl reactions, the formation of acetals. R2C=O + 2R'OH --> R2C(OR')2 + H2O Using a Knudsen cell apparatus, we have measured the rate of uptake of formaldehyde, acetaldehyde, acetone, propanal, and ethanol into sulfuric acid solutions ranging between 40-70 wt% of acid, containing 0-0.1 M of ethanol, acetone or formaldehyde at temperatures of 220-250 K. For all reactant pairs, the aldol condensation path, including self reaction, should be insignificant at the acidities studied. Evidence for reaction between organics was observed for all pairs, except those involving propanal which were likely limited by the very low solubility. We attribute enhanced uptake to the formation of acetals, such as 1,1-diethoxyethane and 2,2- diethoxypropane, among others. Enhanced uptake was observed to proceed on timescales > 1 hour and sometimes shows complex dependence on acidity that is likely related to speciation of the individual carbonyls in acidic solution. The acetal products do not absorb in the visible but are less volatile than parent molecules, allowing for accumulation in sulfuric acid particles, and enhanced uptake. Cross reactions of carbonyls with alcohols in sulfuric acid medium have not been previously measured, yet methanol and ethanol show high solubility and are present at significant concentrations in the UT. Thus even at slow reaction rates, the acetal reaction has ample starting material and proceeds under conditions common to the UT. We will present results for the

  4. Acetobacter aceti possesses a proton motive force-dependent efflux system for acetic acid.

    PubMed

    Matsushita, Kazunobu; Inoue, Taketo; Adachi, Osao; Toyama, Hirohide

    2005-07-01

    Acetic acid bacteria are obligate aerobes able to oxidize ethanol, sugar alcohols, and sugars into their corresponding acids. Among them, Acetobacter and Gluconacetobacter species have very high ethanol oxidation capacity, leading to accumulation of vast amounts of acetic acid outside the cell. Since these bacteria are able to grow in media with high concentrations of acetic acid, they must possess a specific mechanism such as an efflux pump by which they can resist the toxic effects of acetic acid. In this study, the efflux pump of Acetobacter aceti IFO 3283 was examined using intact cells and membrane vesicles. The accumulation of acetic acid/acetate in intact cells was increased by the addition of a proton uncoupler and/or cyanide, suggesting the presence of an energy-dependent efflux system. To confirm this, right-side-out and inside-out membrane vesicles were prepared from A. aceti IFO 3283, and the accumulation of acetic acid/acetate in the vesicles was examined. Upon the addition of a respiratory substrate, the accumulation of acetic acid/acetate in the right-side-out vesicles was largely decreased, while its accumulation was very much increased in the inside-out vesicles. These respiration-dependent phenomena observed in both types of membrane vesicles were all sensitive to a proton uncoupler. Acetic acid/acetate uptake in the inside-out membrane vesicles was dependent not on ATP but on the proton motive force. Furthermore, uptake was shown to be rather specific for acetic acid and to be pH dependent, because higher uptake was observed at lower pH. Thus, A. aceti IFO 3283 possesses a proton motive force-dependent efflux pump for acetic acid.

  5. Oral uptake of nanoparticles: human relevance and the role of in vitro systems.

    PubMed

    Fröhlich, Eleonore; Roblegg, Eva

    2016-10-01

    Nanoparticles (NPs) present in environment, consumer and health products, food and medical applications lead to a high degree of human exposure and concerns about potential adverse effects on human health. For the general population, the exposure through contact with the skin, inhalation and oral uptake are most relevant. Since in vivo testing is only partly able to study the effects of human oral exposure, physiologically relevant in vitro systems are being developed. This review compared the three routes taking into account the estimated concentration, size of the exposed area, morphology of the involved barrier and translocation rate. The high amounts of NPs in food, the large absorption area and the relatively high translocation rate identified oral uptake as most important portal of entry for NPs into the body. Changes of NP properties in the physiological fluids, mechanisms to cross mucus and epithelial barrier, and important issues in the use of laboratory animals for oral exposure are mentioned. The ability of in vitro models to address the varying conditions along the oro-gastrointestinal tract is discussed, and requirements for physiologically relevant in vitro testing of orally ingested NPs are listed.

  6. Testing a structural model of young driver willingness to uptake Smartphone Driver Support Systems.

    PubMed

    Kervick, Aoife A; Hogan, Michael J; O'Hora, Denis; Sarma, Kiran M

    2015-10-01

    There is growing interest in the potential value of using phone applications that can monitor driver behaviour (Smartphone Driver Support Systems, 'SDSSs') in mitigating risky driving by young people. However, their value in this regard will only be realised if young people are willing to use this technology. This paper reports the findings of a study in which a novel structural model of willingness to use SDSSs was tested. Grounded in the driver monitoring and Technology Acceptance (TA) research literature, the model incorporates the perceived risks and gains associated with potential SDSS usage and additional social cognitive factors, including perceived usability and social influences. A total of 333 smartphone users, aged 18-24, with full Irish driving licenses completed an online questionnaire examining willingness or Behavioural Intention (BI) to uptake a SDSS. Following exploratory and confirmatory factor analyses, structural equation modelling indicated that perceived gains and social influence factors had significant direct effects on BI. Perceived risks and social influence also had significant indirect effects on BI, as mediated by perceived gains. Overall, this model accounted for 72.5% of the variance in willingness to uptake SDSSs. Multi-group structural models highlighted invariance of effects across gender, high and low risk drivers, and those likely or unlikely to adopt novel phone app technologies. These findings have implications for our understanding of the willingness of young drivers to adopt and use SDSSs, and highlight potential factors that could be targeted in behavioural change interventions seeking to improve usage rates. PMID:26277411

  7. Testing a structural model of young driver willingness to uptake Smartphone Driver Support Systems.

    PubMed

    Kervick, Aoife A; Hogan, Michael J; O'Hora, Denis; Sarma, Kiran M

    2015-10-01

    There is growing interest in the potential value of using phone applications that can monitor driver behaviour (Smartphone Driver Support Systems, 'SDSSs') in mitigating risky driving by young people. However, their value in this regard will only be realised if young people are willing to use this technology. This paper reports the findings of a study in which a novel structural model of willingness to use SDSSs was tested. Grounded in the driver monitoring and Technology Acceptance (TA) research literature, the model incorporates the perceived risks and gains associated with potential SDSS usage and additional social cognitive factors, including perceived usability and social influences. A total of 333 smartphone users, aged 18-24, with full Irish driving licenses completed an online questionnaire examining willingness or Behavioural Intention (BI) to uptake a SDSS. Following exploratory and confirmatory factor analyses, structural equation modelling indicated that perceived gains and social influence factors had significant direct effects on BI. Perceived risks and social influence also had significant indirect effects on BI, as mediated by perceived gains. Overall, this model accounted for 72.5% of the variance in willingness to uptake SDSSs. Multi-group structural models highlighted invariance of effects across gender, high and low risk drivers, and those likely or unlikely to adopt novel phone app technologies. These findings have implications for our understanding of the willingness of young drivers to adopt and use SDSSs, and highlight potential factors that could be targeted in behavioural change interventions seeking to improve usage rates.

  8. Overlap of copper and iron uptake systems in mitochondria in Saccharomyces cerevisiae.

    PubMed

    Vest, Katherine E; Wang, Jing; Gammon, Micah G; Maynard, Margaret K; White, Olivia L; Cobine, Jai A; Mahone, Wilkerson K; Cobine, Paul A

    2016-01-01

    In Saccharomyces cerevisiae, the mitochondrial carrier family protein Pic2 imports copper into the matrix. Deletion of PIC2 causes defects in mitochondrial copper uptake and copper-dependent growth phenotypes owing to decreased cytochrome c oxidase activity. However, copper import is not completely eliminated in this mutant, so alternative transport systems must exist. Deletion of MRS3, a component of the iron import machinery, also causes a copper-dependent growth defect on non-fermentable carbon. Deletion of both PIC2 and MRS3 led to a more severe respiratory growth defect than either individual mutant. In addition, MRS3 expressed from a high copy number vector was able to suppress the oxygen consumption and copper uptake defects of a strain lacking PIC2. When expressed in Lactococcus lactis, Mrs3 mediated copper and iron import. Finally, a PIC2 and MRS3 double mutant prevented the copper-dependent activation of a heterologously expressed copper sensor in the mitochondrial intermembrane space. Taken together, these data support a role for the iron transporter Mrs3 in copper import into the mitochondrial matrix.

  9. Overlap of copper and iron uptake systems in mitochondria in Saccharomyces cerevisiae

    PubMed Central

    Wang, Jing; Gammon, Micah G.; Maynard, Margaret K.; White, Olivia L.; Cobine, Jai A.; Mahone, Wilkerson K.

    2016-01-01

    In Saccharomyces cerevisiae, the mitochondrial carrier family protein Pic2 imports copper into the matrix. Deletion of PIC2 causes defects in mitochondrial copper uptake and copper-dependent growth phenotypes owing to decreased cytochrome c oxidase activity. However, copper import is not completely eliminated in this mutant, so alternative transport systems must exist. Deletion of MRS3, a component of the iron import machinery, also causes a copper-dependent growth defect on non-fermentable carbon. Deletion of both PIC2 and MRS3 led to a more severe respiratory growth defect than either individual mutant. In addition, MRS3 expressed from a high copy number vector was able to suppress the oxygen consumption and copper uptake defects of a strain lacking PIC2. When expressed in Lactococcus lactis, Mrs3 mediated copper and iron import. Finally, a PIC2 and MRS3 double mutant prevented the copper-dependent activation of a heterologously expressed copper sensor in the mitochondrial intermembrane space. Taken together, these data support a role for the iron transporter Mrs3 in copper import into the mitochondrial matrix. PMID:26763345

  10. Coupling Physiology and Gene Regulation in Bacteria: The Phosphotransferase Sugar Uptake System Delivers the Signals

    NASA Astrophysics Data System (ADS)

    Stülke, Jörg; Hillen, Wolfgang

    In many bacteria a crucial link between metabolism and regulation of catabolic genes is based on the phosphotransferase sugar uptake system (PTS). We summarize the mechanisms of the signaling pathways originating from PTS and leading to regulation of transcription. A protein domain, called PTS regulation domain (PRD), is linked to many antiterminators and transcriptional activators and regulates their activity depending on its state of phosphorylation. Two sites can be phosphorylated in most PRDs: HPr-dependent modification at one site leads to activation while enzyme II dependent phosphorylation of the other site renders it inactive. In addition, PTS components are used to generate cofactors for regulators of transcription. The paradigm is the enzyme II dependent activity of adenylate cyclase determining the cyclic AMP level in Escherichia coli and thereby the activity of the catabolite activator protein. In many gram-positive bacteria catabolite repression is mediated by the catabolite control protein CcpA, which requires HPr Ser-46 phosphate as a cofactor to regulate transcription of catabolic genes. HPr Ser-46 phosphate is produced by HPr kinase, the activity of which is under metabolic control via the concentrations of glycolytic intermediates. These recent results establish a multifaceted regulatory role for PTS in addition to its well-established function in active sugar uptake.

  11. The comparison of 2-18F-2-deoxyglucose and 15-(ortho-123I-phenyl)-pentadecanoic acid uptake in persisting defects on thallium-201 tomography in myocardial infarction

    SciTech Connect

    Henrich, M.M.; Vester, E.; von der Lohe, E.; Herzog, H.; Simon, H.; Kuikka, J.T.; Feinendegen, L.E. )

    1991-07-01

    The myocardial uptake of glucose and fatty acids into 201Tl redistribution defects were studied in 32 patients with myocardial infarction by tomography using 2-18F-2-deoxyglucose (FDG) and 15-(ortho-123I-phenyl)-pentadecanoic acid (oPPA). A total of 1153 segments were analyzed, 408 (35%) of which showed a persistent thallium-defect in stress-redistribution images. Of the segments with a decreased 201Tl uptake in these redistribution tomograms, 50.5% had a decreased uptake of both FDG and oPPA; in 21.8% FDG as well as oPPA uptake was within normal range. Normal FDG uptake but decreased oPPA uptake was detected in 17.4%, whereas 10.3% of the segments had normal oPPA uptake but decreased FDG uptake (chi-square test, p less than 0.001). A significant correlation of FDG and oPPA uptake (r = 0.51) was found in the segments with persistent 201Tl defect. Thus, a substantial fraction of persistent thallium-defects after healed myocardial infarction exhibit FDG as well as oPPA uptake, probably due to residual fatty acid metabolism in partially ischemic regions.

  12. 21 CFR 862.1450 - Lactic acid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Lactic acid test system. 862.1450 Section...

  13. 21 CFR 862.1450 - Lactic acid test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Lactic acid test system. 862.1450 Section...

  14. 21 CFR 862.1450 - Lactic acid test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Lactic acid test system. 862.1450 Section...

  15. 21 CFR 862.1450 - Lactic acid test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Lactic acid test system. 862.1450 Section...

  16. Leptin and insulin modulate nutrient partitioning and weight loss in ob/ob mice through regulation of long-chain fatty acid uptake by adipocytes.

    PubMed

    Fan, Xinqing; Bradbury, Michael W; Berk, Paul D

    2003-09-01

    Leptin treatment of ob/ob mice leads to weight loss appreciably greater than that in pair-fed mice. To test whether this "extra" weight loss is mediated by leptin-induced alterations in nutrient partitioning, the effects in ob/ob mice of subcutaneous leptin infusion (500 ng/h for acid uptake and transporter gene expression were examined. Mice were initially hyperinsulinemic (5.25 +/- 1.57 nmol/L). Plasma insulin decreased by 55 +/- 10% within 8 h of leptin infusion, declining progressively to normal by d 14. The V(max) for saturable adipocyte fatty acid uptake fell from 31.1 +/- 5.6 to 25.2 +/- 4.0 pmol/(s. 50000 cells) (P < 0.05) by 24 h, and to a normal rate (8.0 +/- 0.8 pmol/(s. 50000 cells) by d 21 (P > 0.5 vs. normal C57BL/6J controls). Adipocyte mRNA levels for plasma membrane fatty acid binding protein and fatty acid translocase, putative fatty acid transporters that are up-regulated three- to fourfold in adipocytes from ob/ob mice, had also normalized by d 21. The initial changes in V(max) preceded decreases in food intake and body weight by at least 24 h. In pair-fed mice, insulin levels, V(max) and body weight all declined more slowly than in leptin-treated mice, and all remained significantly elevated compared with normal values at d 21. The data suggest that insulin up-regulates and leptin down-regulates adipocyte fatty acid uptake, leading to alterations in fatty acid partitioning that affect adiposity.

  17. Differing patterns of striatal sup 18 F-dopa uptake in Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy

    SciTech Connect

    Brooks, D.J.; Ibanez, V.; Sawle, G.V.; Quinn, N.; Lees, A.J.; Mathias, C.J.; Bannister, R.; Marsden, C.D.; Frackowiak, R.S. )

    1990-10-01

    Using positron emission tomography (PET), we studied regional striatal 18F-dopa uptake in 16 patients with L-dopa-responsive Parkinson's disease (PD), 18 patients with multiple system atrophy, and 10 patients with progressive supranuclear palsy. Results were compared with those of 30 age-matched normal volunteers. The patients with PD showed significantly reduced mean uptake of 18F-dopa in the caudate and putamen compared to controls, but while function in the posterior part of the putamen was severely impaired (45% of normal), function in the anterior part of the putamen and in the caudate was relatively spared (62% and 84% of normal). Mean 18F-dopa uptake in the posterior putamen was depressed to similar levels in all patients. Unlike patients with PD, the patients with progressive supranuclear palsy showed equally severe impairment of mean 18F-dopa uptake in the anterior and posterior putamen. Caudate 18F-dopa uptake was also significantly lower in patients with progressive supranuclear palsy than in patients with PD, being depressed to the same level as that in the putamen. Mean 18F-dopa uptake values in the anterior putamen and caudate in patients with multiple system atrophy lay between PD and progressive supranuclear palsy levels. Locomotor disability of individual patients with PD or multiple system atrophy correlated with decline in striatal 18F-dopa uptake, but this was not the case for the patients with progressive supranuclear palsy. We conclude that patients with PD have selective nigral pathological features with relative preservation of the dopaminergic function in the anterior putamen and caudate, whereas there is progressively more extensive nigral involvement in multiple system atrophy and progressive supranuclear palsy.

  18. Trivalent chromium alleviates oleic acid induced steatosis in SMMC-7721 cells by decreasing fatty acid uptake and triglyceride synthesis.

    PubMed

    Wang, Song; Wang, Jian; Zhang, Xiaonan; Hu, Linlin; Fang, Zhijia; Huang, Zhiwei; Shi, Ping

    2016-10-01

    Trivalent chromium [Cr(III)] has been shown as an essential trace element for human health. Previous studies depict that Cr(III) plays important roles in maintaining normal glucose and lipid metabolism, whereas its effect on the hepatic lipid metabolism is still unknown. In the present study, we investigated the effects and underlying mechanisms of Cr on hepatic steatosis induced by oleic acid (OA) in human hepatoma SMMC-7721 cells. Hepatic steatosis model was co-administered with Cr. Indexes of lipid accumulation were determined and associated genes expression were analyzed. The data showed that OA could induce lipid accumulation and triglyceride (TG) content in SMMC-7721 cells, and significantly increase the expression of cluster of differentiation 36 (CD36) and diacylglycerol acyltransferase 2 (DGAT2). This steatosis effect of OA was ameliorated by Cr. The TG accumulation and up-regulation of CD36 and DGAT2 genes followed steatosis induction were inhibited by Cr. After the treatment of Cr, excessive intracellular OA content was also attenuated. Furthermore, Cr still performed inhibitory effect of DGAT2 expression at the presence of DGAT2 agonist or inhibitor, which indicated that the inhibitory effect of Cr on lipogenesis is associated with the downregulation of DGAT2 expression. These findings demonstrate that Cr alleviates hepatic steatosis via suppressing CD36 expression to prevent fatty acid uptake, as well as suppressing DGAT2 expression to inhibit TG synthesis. It suggests that CD36 and DGAT2 might become the novel drug targets for their properties in hepatic steatosis. Most importantly, Cr may be a potential anti-steatosis candidate to offer protective effects against liver damage. PMID:27497686

  19. Investigating the Uptake Mechanisms of Hydrogen Peroxide to Single and Polycrystalline Ice with a Novel Flow Tube System

    NASA Astrophysics Data System (ADS)

    Hong, Angela; Ammann, Markus; Bartels-Rausch, Thorsten

    2016-04-01

    Air-ice chemical interactions are important for describing the distribution and subsequent chemical fate of trace atmospheric gases within ice and snow and determining the oxidative capacities of these environments. The nature of this interaction is governed by a compound's physicochemical properties as well as ice microstructure. Hydrogen peroxide (H2O2), a reservoir of HOx radicals in the atmosphere and an important chromophore in snow and ice, is a trace gas that demonstrates complex uptake behaviour to frozen aqueous media by the reversible, fast adsorption to the air-ice interface, aggregation, and lateral interactions, and a slower process, ostensibly via uptake into the bulk. However, the exact mechanism and kinetics for the slow uptake of H2O2 and the size of this reservoir is unknown. It is important to describe and quantify this loss term, over environmentally-relevant timescales, accommodation of H2O2 into the bulk may be the dominant process which controls the composition and chemistry of the snow and overlying atmosphere. We hypothesize that the slow uptake of H2O2 occurs by diffusion into the grain boundaries of ice. To provide mechanistic insight to the macroscopic phenomenon of atmospheric gas uptake to ice, and discern various mechanisms including adsorption to air-ice interface and accommodation into the bulk through uptake into grain boundaries, we design, machine, and validate a novel flow reactor system featuring a Drilled Ice Flow Tube (DIFT). Our flow reactor system is uniquely suited to testing these uptake mechanisms: by controlling the degree of grain boundaries present in the DIFT (ie. monocrystalline or polycrystalline), we can directly observe the effect of the ice microstructure on the adsorptive and bulk uptake of trace atmospheric gases over long timescales (eg. on the order of hours). Here, we describe method development of the DIFT and demonstrate using polarised microscopy imagery that our experimental set-up allows for the direct

  20. Artificial hydrogenases: biohybrid and supramolecular systems for catalytic hydrogen production or uptake.

    PubMed

    Caserta, Giorgio; Roy, Souvik; Atta, Mohamed; Artero, Vincent; Fontecave, Marc

    2015-04-01

    There is an urgent need for cheap, abundant and efficient catalysts as an alternative to platinum for hydrogen production and oxidation in (photo)electrolyzers and fuel cells. Hydrogenases are attractive solutions. These enzymes use exclusively nickel and iron in their active sites and function with high catalytic rates at the thermodynamic equilibrium. As an alternative, a number of biomimetic and bioinspired catalysts for H2 production and/or uptake, based on Ni, Fe and Co, have been developed and shown to display encouraging performances. In this review we discuss specifically recent approaches aiming at incorporating these compounds within oligomeric and polymeric hosts. The latter are most often biological compounds (peptides, proteins, polysaccharides, etc.) but we also discuss non-biological scaffolds (synthetic polymers, Metal-organic-Frameworks, etc.) which can provide the appropriate environment to tune the activity and stability of the synthetic catalysts. These supramolecular catalytic systems thus define a class of original compounds so-called artificial hydrogenases.

  1. Selective fetal malnutrition: the effect of nicotine, ethanol, and acetaldehyde upon in vitro uptake of alpha-aminoisobutyric acid by human term placental villous slices.

    PubMed

    Fisher, S E; Atkinson, M; Van Thiel, D H

    1984-01-01

    Intrauterine growth retardation (IUGR) is often associated with either tobacco smoking or ethanol abuse during pregnancy, and the two habits usually coexist. We tested the hypothesis that nicotine is placentotoxic, thereby contributing to tobacco-associated IUGR. In vitro uptake of alpha-aminoisobutyric acid (AIB) by normal human placental slices was examined in the presence of nicotine, 0.2-20 microM. Significant (p less than 0.05) reductions in AIB uptake were observed for nicotine, 2.5-20 microM, with a linear dose-response. Since ethanol, and its major metabolite, acetaldehyde, have previously been shown to impair human placental uptake of AIB, these two substances were tested for synergism with nicotine. No interaction was observed between nicotine (0.2 microM) and ethanol (1,000 mg/dl). An increased inhibition was observed for the combination of nicotine (0.2 microM) and acetaldehyde (500 microM), but two-way analysis of variance indicated that the effects are additive, rather than synergistic. It is concluded that nicotine inhibits term human placental transport of the actively transported, nonmetabolized amino acid, AIB. Such placentotoxicity may be a contributing factor in tobacco-associated IUGR. Abuse of ethanol concurrent with tobacco smoking by a pregnant woman may be more detrimental to placental amino acid transport than either substance alone.

  2. Functional Dependence between Septal Protein SepJ from Anabaena sp. Strain PCC 7120 and an Amino Acid ABC-Type Uptake Transporter

    PubMed Central

    Escudero, Leticia; Mariscal, Vicente

    2015-01-01

    ABSTRACT In the diazotrophic filaments of heterocyst-forming cyanobacteria, two different cell types, the CO2-fixing vegetative cells and the N2-fixing heterocysts, exchange nutrients, including some amino acids. In the model organism Anabaena sp. strain PCC 7120, the SepJ protein, composed of periplasmic and integral membrane (permease) sections, is located at the intercellular septa joining adjacent cells in the filament. The unicellular cyanobacterium Synechococcus elongatus strain PCC 7942 bears a gene, Synpcc7942_1024 (here designated dmeA), encoding a permease homologous to the SepJ permease domain. Synechococcus strains lacking dmeA or lacking dmeA and expressing Anabaena sepJ were constructed. The Synechococcus dmeA mutant showed a significant 22 to 32% decrease in the uptake of aspartate, glutamate, and glutamine, a phenotype that could be partially complemented by Anabaena sepJ. Synechococcus mutants of an ATP-binding-cassette (ABC)-type transporter for polar amino acids showed >98% decreased uptake of glutamate irrespective of the presence of dmeA or Anabaena sepJ in the same strain. Thus, Synechococcus DmeA or Anabaena SepJ is needed to observe full (or close to full) activity of the ABC transporter. An Anabaena sepJ deletion mutant was significantly impaired in glutamate and aspartate uptake, which also in this cyanobacterium requires the activity of an ABC-type transporter for polar amino acids. SepJ appears therefore to generally stimulate the activity of cyanobacterial ABC-type transporters for polar amino acids. Conversely, an Anabaena mutant of three ABC-type transporters for amino acids was impaired in the intercellular transfer of 5-carboxyfluorescein, a SepJ-related property. Our results unravel possible functional interactions in transport elements important for diazotrophic growth. IMPORTANCE Membrane transporters are essential for many aspects of cellular life, from uptake and export of substances in unicellular organisms to intercellular

  3. A systems toxicology approach on the mechanism of uptake and toxicity of MWCNT in Caenorhabditis elegans.

    PubMed

    Eom, Hyun-Jeong; Roca, Carlos P; Roh, Ji-Yeon; Chatterjee, Nivedita; Jeong, Jae-Seong; Shim, Ilseob; Kim, Hyun-Mi; Kim, Phil-Je; Choi, Kyunghee; Giralt, Francesc; Choi, Jinhee

    2015-09-01

    The increased volumes of carbon nanotubes (CNTs) being utilized in industrial and biomedical processes carries with it an increased risk of unintentional release into the environment, requiring a thorough hazard and risk assessment. In this study, the toxicity of pristine and hydroxylated (OH-) multiwall CNTs (MWCNTs) was investigated in the nematode Caenorhabditis elegans using an integrated systems toxicology approach. To gain an insight into the toxic mechanism of MWCNTs, microarray and proteomics were conducted for C. elegans followed by pathway analyses. The results of pathway analyses suggested endocytosis, phagocytosis, oxidative stress and endoplasmic reticulum (ER) stress, as potential mechanisms of uptake and toxicity, which were subsequently investigated using loss-of-function mutants of genes of those pathways. The expression of phagocytosis related genes (i.e. ced-10 and rab-7) were significantly increased upon exposure to OH-MWCNT, concomitantly with the rescued toxicity by loss-of-function mutants of those genes, such as ced-10(n3246) and rab-7(ok511). An increased sensitivity of the hsp-4(gk514) mutant by OH-MWCNT, along with a decreased expression of hsp-4 at both gene and protein level suggests that MWCNTs may affect ER stress response in C. elegans. Collectively, the results implied phagocytosis to be a potential mechanism of uptake of MWCNTs, and ER and oxidative stress as potential mechanisms of toxicity. The integrated systems toxicology approach applied in this study provided a comprehensive insight into the toxic mechanism of MWCNTs in C. elegans, which may eventually be used to develop an "Adverse Outcome Pathway (AOP)", a recently introduced concept as a conceptual framework to link molecular level responses to higher level effects.

  4. Exogenous abscisic acid application decreases cadmium accumulation in Arabidopsis plants, which is associated with the inhibition of IRT1-mediated cadmium uptake

    PubMed Central

    Fan, Shi Kai; Fang, Xian Zhi; Guan, Mei Yan; Ye, Yi Quan; Lin, Xian Yong; Du, Shao Ting; Jin, Chong Wei

    2014-01-01

    Cadmium (Cd) contamination of agricultural soils is an increasingly serious problem. Measures need to be developed to minimize Cd entering the human food chain from contaminated soils. We report here that, under Cd exposure condition, application with low doses of (0.1–0.5 μM) abscisic acid (ABA) clearly inhibited Cd uptake by roots and decreased Cd level in Arabidopsis wild-type plants (Col-0). Expression of IRT1 in roots was also strongly inhibited by ABA treatment. Decrease in Cd uptake and the inhibition of IRT1 expression were clearly lesser pronounced in an ABA-insensitive double mutant snrk2.2/2.3 than in the Col-0 in response to ABA application. The ABA-decreased Cd uptake was found to correlate with the ABA-inhibited IRT1 expression in the roots of Col-0 plants fed two different levels of iron. Furthermore, the Cd uptake of irt1 mutants was barely affected by ABA application. These results indicated that inhibition of IRT1 expression is involved in the decrease of Cd uptake in response to exogenous ABA application. Interestingly, ABA application increased the iron level in both Col-0 plants and irt1 mutants, suggesting that ABA-increased Fe acquisition does not depend on the IRT1 function, but on the contrary, the ABA-mediated inhibition of IRT1 expression may be due to the elevation of iron level in plants. From our results, we concluded that ABA application might increase iron acquisition, followed by the decrease in Cd uptake by inhibition of IRT1 activity. Thus, for crop production in Cd contaminated soils, developing techniques based on ABA application potentially is a promising approach for reducing Cd accumulation in edible organs in plants. PMID:25566293

  5. Effects of cAMP modulators on long-chain fatty-acid uptake and utilization by electrically stimulated rat cardiac myocytes.

    PubMed Central

    Luiken, J J F P; Willems, J; Coort, S L M; Coumans, W A; Bonen, A; Van Der Vusse, G J; Glatz, J F C

    2002-01-01

    Recently, we established that cellular contractions increase long-chain fatty-acid (FA) uptake by cardiac myocytes. This increase is dependent on the transport function of an 88 kDa membrane FA transporter, FA translocase (FAT/CD36), and, in analogy to skeletal muscle, is likely to involve its translocation from an intracellular pool to the sarcolemma. In the present study, we investigated whether cAMP-dependent signalling is involved in this translocation process. Isoproterenol, dibutyryl-cAMP and the phosphodiesterase (PDE) inhibitor, amrinone, which markedly raised the intracellular cAMP level, did not affect cellular FA uptake, but influenced the fate of intracellular FAs by directing these to mitochondrial oxidation in electrostimulated cardiac myocytes. The PDE inhibitors 3-isobutyl-1-methylxanthine, milrinone and dipyridamole each significantly stimulated FA uptake as well as intracellular cAMP levels, but these effects were quantitatively unrelated. The stimulatory effects of these PDE inhibitors were antagonized by sulpho- N -succinimidylpalmitate, indicating the involvement of FAT/CD36, albeit that the different PDE inhibitors use different molecular mechanisms to stimulate FAT/CD36-mediated FA uptake. Notably, 3-isobutyl-1-methylxanthine and milrinone increased the intrinsic activity of FAT/CD36, possibly through its covalent modification, and dipyridamole induces translocation of FAT/CD36 to the sarcolemma. Elevation of intracellular cGMP, but not of cAMP, by the PDE inhibitor zaprinast did not have any effect on FA uptake and metabolism by cardiac myocytes. The stimulatory effects of PDE inhibitors on cardiac FA uptake should be considered when applying these agents in clinical medicine. PMID:12093365

  6. Anti-obesity actions of green tea: possible involvements in modulation of the glucose uptake system and suppression of the adipogenesis-related transcription factors.

    PubMed

    Ashida, Hitoshi; Furuyashiki, Takashi; Nagayasu, Hironobu; Bessho, Hiroaki; Sakakibara, Hiroyuki; Hashimoto, Takashi; Kanazawa, Kazuki

    2004-01-01

    To investigate mechanisms of the anti-obesity actions of green tea in vivo, rats were given green tea instead of drinking water for 3 weeks. It was confirmed that green tea reduced adipose tissue weight without any change in body weight, other tissue weights, and food and water intakes. Green tea also significantly reduced the plasma levels of cholesterols and free fatty acids. Certain catechins existed in the plasma at 0.24 microM under our experimental conditions, though most of them existed as conjugated forms. For mechanisms of the anti-obesity actions, green tea significantly reduced glucose uptake accompanied by a decrease in translocation of glucose transporter 4 (GLUT4) in adipose tissue, while it significantly stimulated the glucose uptake with GLUT4 translocation in skeletal muscle. Moreover, green tea suppressed the expression of peroxisome proliferator-activated receptor gamma and the activation of sterol regulatory element binding protein-1 in adipose tissue. In conclusion, green tea modulates the glucose uptake system in adipose tissue and skeletal muscle and suppresses the expression and/or activation of adipogenesis-related transcription factors, as the possible mechanisms of its anti-obesity actions.

  7. Acid sensing by the Drosophila olfactory system.

    PubMed

    Ai, Minrong; Min, Soohong; Grosjean, Yael; Leblanc, Charlotte; Bell, Rati; Benton, Richard; Suh, Greg S B

    2010-12-01

    The odour of acids has a distinct quality that is perceived as sharp, pungent and often irritating. How acidity is sensed and translated into an appropriate behavioural response is poorly understood. Here we describe a functionally segregated population of olfactory sensory neurons in the fruitfly, Drosophila melanogaster, that are highly selective for acidity. These olfactory sensory neurons express IR64a, a member of the recently identified ionotropic receptor (IR) family of putative olfactory receptors. In vivo calcium imaging showed that IR64a+ neurons projecting to the DC4 glomerulus in the antennal lobe are specifically activated by acids. Flies in which the function of IR64a+ neurons or the IR64a gene is disrupted had defects in acid-evoked physiological and behavioural responses, but their responses to non-acidic odorants remained unaffected. Furthermore, artificial stimulation of IR64a+ neurons elicited avoidance responses. Taken together, these results identify cellular and molecular substrates for acid detection in the Drosophila olfactory system and support a labelled-line mode of acidity coding at the periphery. PMID:21085119

  8. Mouse Strain Impacts Fatty Acid Uptake and Trafficking in Liver, Heart, and Brain: A Comparison of C57BL/6 and Swiss Webster Mice.

    PubMed

    Seeger, D R; Murphy, E J

    2016-05-01

    C57BL/6 and Swiss Webster mice are used to study lipid metabolism, although differences in fatty acid uptake between these strains have not been reported. Using a steady state kinetic model, [1-(14)C]16:0, [1-(14)C]20:4n-6, or [1-(14)C]22:6n-3 was infused into awake, adult male mice and uptake into liver, heart, and brain determined. The integrated area of [1-(14)C]20:4n-6 in plasma was significantly increased in C57BL/6 mice, but [1-(14)C]16:0 and [1-(14)C]22:6n-3 were not different between groups. In heart, uptake of [1-(14)C]20:4n-6 was increased 1.7-fold in C57BL/6 mice. However, trafficking of [1-(14)C]22:6n-3 into the organic fraction of heart was significantly decreased 33 % in C57BL/6 mice. Although there were limited differences in fatty acid tracer trafficking in liver or brain, [1-(14)C]16:0 incorporation into liver neutral lipids was decreased 18 % in C57BL/6 mice. In heart, the amount of [1-(14)C]16:0 and [1-(14)C]22:6n-3 incorporated into total phospholipids were decreased 45 and 49 %, respectively, in C57BL/6 mice. This was accounted for by a 53 and 37 % decrease in [1-(14)C]16:0 and 44 and 52 % decrease in [1-(14)C]22:6n-3 entering ethanolamine glycerophospholipids and choline glycerophospholipids, respectively. In contrast, there was a significant increase in [1-(14)C]20:4n-6 esterification into all heart phospholipids of C57BL/6 mice. Although changes in uptake were limited to heart, several significant differences were found in fatty acid trafficking into heart, liver, and brain phospholipids. In summary, our data demonstrates differences in tissue fatty acid uptake and trafficking between mouse strains is an important consideration when carrying out fatty acid metabolic studies.

  9. Sulfuric acid thermoelectrochemical system and method

    DOEpatents

    Ludwig, Frank A.

    1989-01-01

    A thermoelectrochemical system in which an electrical current is generated between a cathode immersed in a concentrated sulfuric acid solution and an anode immersed in an aqueous buffer solution of sodium bisulfate and sodium sulfate. Reactants consumed at the electrodes during the electrochemical reaction are thermochemically regenerated and recycled to the electrodes to provide continuous operation of the system.

  10. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-08-17

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  11. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-12-21

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  12. Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: implications for land and water reclamation in tropical regions.

    PubMed

    Lottermoser, Bernd G; Ashley, Paul M

    2011-10-01

    This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions.

  13. Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: implications for land and water reclamation in tropical regions.

    PubMed

    Lottermoser, Bernd G; Ashley, Paul M

    2011-10-01

    This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions. PMID:21550704

  14. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps

    PubMed Central

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A. S.; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-01-01

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K+ uptake system in the Venus flytrap. In search of K+ transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K+-transporter genes into Xenopus oocytes, however, both putative K+ transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K+ transporter 1 (AKT1), we coexpressed the putative K+ transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K+ uptake. DmKT1 was found to be a K+-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around −120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K+, reducing its concentration from millimolar levels down to trace levels. PMID:25997445

  15. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps.

    PubMed

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A S; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-06-01

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K(+) uptake system in the Venus flytrap. In search of K(+) transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K(+)-transporter genes into Xenopus oocytes, however, both putative K(+) transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K(+) transporter 1 (AKT1), we coexpressed the putative K(+) transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K(+) uptake. DmKT1 was found to be a K(+)-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around -120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K(+), reducing its concentration from millimolar levels down to trace levels. PMID:25997445

  16. Identification and Characterization of the Nickel Uptake System for Urease Biogenesis in Streptococcus salivarius 57.I

    PubMed Central

    Chen, Yi-Ywan M.; Burne, Robert A.

    2003-01-01

    Ureases are multisubunit enzymes requiring Ni2+ for activity. The low pH-inducible urease gene cluster in Streptococcus salivarius 57.I is organized as an operon, beginning with ureI, followed by ureABC (structural genes), and ureEFGD (accessory genes). Urease biogenesis also requires a high-affinity Ni2+ uptake system. By searching the partial genome sequence of a closely related organism, Streptococcus thermophilus LMG18311, three open reading frame (ORFs) homologous to those encoding proteins involved in cobalamin biosynthesis and cobalt transport (cbiMQO) were identified immediately 3′ to the ure operon. To determine whether these genes were involved in urease biogenesis by catalyzing Ni2+ uptake in S. salivarius, regions 3′ to ureD were amplified by PCRs from S. salivarius by using primers identical to the S. thermophilus sequences. Sequence analysis of the products revealed three ORFs. Reverse transcriptase PCR was used to demonstrate that the ORFs are transcribed as part of the ure operon. Insertional inactivation of ORF1 with a polar kanamycin marker completely abolished urease activity and the ability to accumulate 63Ni2+ during growth. Supplementation of the growth medium with NiCl2 at concentrations as low as 2.5 μM partially restored urease activity in the mutant. Both wild-type and mutant strains showed enhanced urease activity when exogenous Ni2+ was provided at neutral pH. Enhancement of urease activity by adding nickel was regulated at the posttranslational level. Thus, ORF1, ORF2, and ORF3 are part of the ure operon, and these genes, designated ureM, ureQ, and ureO, respectively, likely encode a Ni2+-specific ATP-binding cassette transporter. PMID:14617641

  17. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps.

    PubMed

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A S; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-06-01

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K(+) uptake system in the Venus flytrap. In search of K(+) transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K(+)-transporter genes into Xenopus oocytes, however, both putative K(+) transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K(+) transporter 1 (AKT1), we coexpressed the putative K(+) transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K(+) uptake. DmKT1 was found to be a K(+)-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around -120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K(+), reducing its concentration from millimolar levels down to trace levels.

  18. System A Amino Acid Transport-Targeted Brain and Systemic Tumor PET Imaging Agents 2-Amino-3-[18F]Fluoro-2-Methylpropanoic Acid and 3-[18F]Fluoro-2-Methyl-2-(Methylamino)propanoic Acid

    PubMed Central

    Yu, Weiping; McConathy, Jonathan; Olson, Jeffrey J.; Goodman, Mark M.

    2014-01-01

    Introduction Amino acid based radiotracers target tumor cells through increased uptake by membrane-associated amino acid transport (AAT) systems. In the present study, four structurally related non-natural 18F-labeled amino acids, (R)- and (S)-[18F]FAMP 1 and (R)- and (S)-[18F]MeFAMP 2 have been prepared and evaluated in vitro and in vivo for their potential utility in brain and systemic tumor imaging based upon primarily system A transport with positron emission tomography (PET). Methods The transport of enantiomers of [18F]FAMP 1 and [18F]MeFAMP 2 was measured through in vitro uptake assays in human derived cancer cells including A549 (lung), DU145 (prostate), SKOV3 (ovary), MDA MB468 (breast) and U87 (brain) in the presence and absence of amino acid transporter inhibitors. The in vivo biodistribution of these tracers was evaluated using tumor mice xenografts at 15, 30, 60 and 120 min post injection. Results All four tracers showed moderate to high levels of uptake (1- 9 %ID/5×105 cells) by the cancer cell lines tested in vitro. AAT cell inhibition assays demonstrated that (R)-[18F]1 and (S)-[18F]1 entered these tumor cells via mixed AATs, likely but not limited to system A and system L. In contrast, (R)-[18F]2 and (S)-[18F]2 showed high selectivity for system A AAT. Similar to the results of in vitro cell studies, the tumor uptake of all four tracers was good to high and persisted over the 2 hours time course of in vivo studies. The accumulation of these tracers was higher in tumor than most normal tissues including blood, brain, muscle, bone, heart, and lung, and the tracers with the highest in vitro selectivity for system A AAT generally demonstrated the best tumor imaging properties. Higher uptake of these tracers was observed in the pancreas, kidney and spleen compared to tumors. Conclusions These preclinical studies demonstrate good imaging properties in a wide range of tumors for all four amino acids evaluated with (R)-[18F]2 having the highest

  19. Static magnetic field reduced exogenous oligonucleotide uptake by spermatozoa using magnetic nanoparticle gene delivery system

    NASA Astrophysics Data System (ADS)

    Katebi, Samira; Esmaeili, Abolghasem; Ghaedi, Kamran

    2016-03-01

    Spermatozoa could introduce exogenous oligonucleotides of interest to the oocyte. The most important reason of low efficiency of sperm mediated gene transfer (SMGT) is low uptake of exogenous DNA by spermatozoa. The aim of this study was to evaluate the effects of static magnetic field on exogenous oligonucleotide uptake of spermatozoa using magnetofection method. Magnetic nanoparticles (MNPs) associated with the labeled oligonucleotides were used to increase the efficiency of exogenous oligonucleotide uptake by rooster spermatozoa. We used high-field/high-gradient magnet (NdFeB) to enhance and accelerate exogenous DNA sedimentation at the spermatozoa surface. Flow cytometry analysis was performed to measure viability and percentage of exogenous oligonucleotide uptake by sperm. Flow cytometry analysis showed a significant increase in exogenous oligonucleotide uptake by rooster spermatozoa (P<0.001) when spermatozoa were incubated in exogenous oligonucleotide solution and MNPs. However, by applying static magnetic field during magnetofection method, a significant decrease in exogenous oligonucleotide uptake was observed (P<0.05). Findings of this study showed that MNPs were effective to increase exogenous oligonucleotide uptake by rooster spermatozoa; however unlike others studies, static magnetic field, was not only ineffective to enhance exogenous oligonucleotide uptake by rooster spermatozoa but also led to reduction in efficiency of magnetic nanoparticles in gene transfer.

  20. The role and uptake of private health insurance in different health care systems: are there lessons for developing countries?

    PubMed Central

    Odeyemi, Isaac AO; Nixon, John

    2013-01-01

    Background Social and national health insurance schemes are being introduced in many developing countries in moving towards universal health care. However, gaps in coverage are common and can only be met by out-of-pocket payments, general taxation, or private health insurance (PHI). This study provides an overview of PHI in different health care systems and discusses factors that affect its uptake and equity. Methods A representative sample of countries was identified (United States, United Kingdom, The Netherlands, France, Australia, and Latvia) that illustrates the principal forms and roles of PHI. Literature describing each country’s health care system was used to summarize how PHI is utilized and the factors that affect its uptake and equity. Results In the United States, PHI is a primary source of funding in conjunction with tax-based programs to support vulnerable groups; in the UK and Latvia, PHI is used in a supplementary role to universal tax-based systems; in France and Latvia, complementary PHI is utilized to cover gaps in public funding; in The Netherlands, PHI is supplementary to statutory private and social health insurance; in Australia, the government incentivizes the uptake of complementary PHI through tax rebates and penalties. The uptake of PHI is influenced by age, income, education, health care system typology, and the incentives or disincentives applied by governments. The effect on equity can either be positive or negative depending on the type of PHI adopted and its role within the wider health care system. Conclusion PHI has many manifestations depending on the type of health care system used and its role within that system. This study has illustrated its common applications and the factors that affect its uptake and equity in different health care systems. The results are anticipated to be helpful in informing how developing countries may utilize PHI to meet the aim of achieving universal health care. PMID:23494071

  1. A Highly Conserved Bacterial D-Serine Uptake System Links Host Metabolism and Virulence

    PubMed Central

    Connolly, James P. R.; Gabrielsen, Mads; Goldstone, Robert J.; Grinter, Rhys; Wang, Dai; Cogdell, Richard J.; Walker, Daniel; Smith, David G. E.; Roe, Andrew J.

    2016-01-01

    The ability of any organism to sense and respond to challenges presented in the environment is critically important for promoting or restricting colonization of specific sites. Recent work has demonstrated that the host metabolite D-serine has the ability to markedly influence the outcome of infection by repressing the type III secretion system of enterohaemorrhagic Escherichia coli (EHEC) in a concentration-dependent manner. However, exactly how EHEC monitors environmental D-serine is not understood. In this work, we have identified two highly conserved members of the E. coli core genome, encoding an inner membrane transporter and a transcriptional regulator, which collectively help to “sense” levels of D-serine by regulating its uptake from the environment and in turn influencing global gene expression. Both proteins are required for full expression of the type III secretion system and diversely regulated prophage-encoded effector proteins demonstrating an important infection-relevant adaptation of the core genome. We propose that this system acts as a key safety net, sampling the environment for this metabolite, thereby promoting colonization of EHEC to favorable sites within the host. PMID:26727373

  2. Nonrecirculating hydroponic systems suitable for uptake studies at very low nutrient concentrations

    SciTech Connect

    Gutschick, V.P.; Kay, L.E. )

    1991-04-01

    The authors describe the mechanical, electronic, hydraulic, and structural design of a nonrecirculating hydroponic system. The system is particularly suited to sutides at very low nutrient concentratons, for which on-line concentration monitoring methods either do not exist or are costly and limited to monitoring relatively few indivitual plants. Solutions are mised automatically to chosen concentrations, which can be set differently for every pump fed from a master supply of deionized water and nutrient concentrates. Pumping rates can be varied over a 50-fold range, up to 400 liters per day, which suffices to maintain a number of large, post-seedling plants in rapid growth at (sub)micromolar levels of N and P. The outflow of each pump is divided among as many as 12 separate root chambers. In each changer one may monitor uptake by individual plant roots or segments thereof, by measuring nutrient depletion in batch samples of solution. The system is constructed from nontoxic materials that do not adsorb nutrient ions; no transient shifts of nitrate and phosphate concentrations are observable at the submicromolar level. Nonrecirculaton of solution limits porblems of pH shifts, microbial contamination, and cumulative imbalances in unmonitored nutrients. They note several disadvantages, principally related to high consumption of deionized water and solutes. The reciprocating pumps can be constructed inexpensively, particularly by the researcher. They also report previously unattainable control of passive temperature rise of chambers exposed to full sunlight, by use of white epoxy paint.

  3. A Highly Conserved Bacterial D-Serine Uptake System Links Host Metabolism and Virulence.

    PubMed

    Connolly, James P R; Gabrielsen, Mads; Goldstone, Robert J; Grinter, Rhys; Wang, Dai; Cogdell, Richard J; Walker, Daniel; Smith, David G E; Roe, Andrew J

    2016-01-01

    The ability of any organism to sense and respond to challenges presented in the environment is critically important for promoting or restricting colonization of specific sites. Recent work has demonstrated that the host metabolite D-serine has the ability to markedly influence the outcome of infection by repressing the type III secretion system of enterohaemorrhagic Escherichia coli (EHEC) in a concentration-dependent manner. However, exactly how EHEC monitors environmental D-serine is not understood. In this work, we have identified two highly conserved members of the E. coli core genome, encoding an inner membrane transporter and a transcriptional regulator, which collectively help to "sense" levels of D-serine by regulating its uptake from the environment and in turn influencing global gene expression. Both proteins are required for full expression of the type III secretion system and diversely regulated prophage-encoded effector proteins demonstrating an important infection-relevant adaptation of the core genome. We propose that this system acts as a key safety net, sampling the environment for this metabolite, thereby promoting colonization of EHEC to favorable sites within the host.

  4. Nonrecirculating Hydroponic System Suitable for Uptake Studies at Very Low Nutrient Concentrations 1

    PubMed Central

    Gutschick, Vincent P.; Kay, Lou Ellen

    1991-01-01

    We describe the mechanical, electronic, hydraulic, and structural design of a nonrecirculating hydroponic system. The system is particularly suited to studies at very low nutrient concentrations, for which on-line concentration monitoring methods either do not exist or are costly and limited to monitoring relatively few individual plants. Solutions are mixed automatically to chosen concentrations, which can be set differently for every pump fed from a master supply of deionized water and nutrient concentrates. Pumping rates can be varied over a 50-fold range, up to 400 liters per day, which suffices to maintain a number of large, post-seedling plants in rapid growth at (sub)micromolar levels of N and P. The outflow of each pump is divided among as many as 12 separate root chambers. In each chamber one may monitor uptake by individual plant roots or segments thereof, by measuring nutrient depletion in batch samples of solution. The system is constructed from nontoxic materials that do not adsorb nutrient ions; no transient shifts of nitrate and phosphate concentrations are observable at the submicromolar level. Nonrecirculation of solutions limits problems of pH shifts, microbial contamination, and cumulative imbalances in unmonitored nutrients. We note several disadvantages, principally related to high consumption of deionized water and solutes. The reciprocating pumps can be constructed inexpensively, particularly by the researcher. We also report previously unattainable control of passive temperature rise of chambers exposed to full sunlight, by use of white epoxy paint. PMID:16668100

  5. 21 CFR 862.1290 - Fatty acids test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Fatty acids test system. 862.1290 Section 862.1290....1290 Fatty acids test system. (a) Identification. A fatty acids test system is a device intended to measure fatty acids in plasma and serum. Measurements of fatty acids are used in the diagnosis...

  6. 21 CFR 862.1295 - Folic acid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Folic acid test system. 862.1295 Section 862.1295....1295 Folic acid test system. (a) Identification. A folic acid test system is a device intended to measure the vitamin folic acid in plasma and serum. Folic acid measurements are used in the diagnosis...

  7. Determining the functional role of waterborne amino acid uptake in hagfish nutrition: a constitutive pathway when fasting or a supplementary pathway when feeding?

    PubMed

    Glover, Chris N; Blewett, Tamzin A; Wood, Chris M

    2016-10-01

    Hagfish are unique among aquatic "vertebrates" in their ability to absorb amino acids directly from the water via skin and gill epithelia, but it is unknown whether this phenomenon extends beyond a few studied substrates; what effect fed state has on absorption; and what functional role this may play in hagfish nutrition. Using in vivo and in vitro transport assays, uptake and tissue distribution of the waterborne amino acids L-alanine, L-lysine, and L-phenylalanine were examined as a function of fed state. All three amino acids were shown to be taken up from the water (lysine and phenylalanine for the first time). Following immersion in radiolabelled solutions for 24 h, phenylalanine was the amino acid that accumulated at the highest levels in almost all tissues, with the highest accumulation noted in red blood cells and bile, followed by gill and liver. In general, tissues of fed hagfish displayed a significantly reduced phenylalanine accumulation compared to tissues of hagfish fasted for 3 weeks. An in vitro assay showed that phenylalanine was transported across the skin at the highest rate, with the uptake of lysine occurring at the lowest rate. Feeding status had no significant effect on in vitro transport. These data indicate that dissolved organic nutrients are a significant source of nutrition to hagfish, and may be relatively more important during periods of fasting than during periods of feeding when immersed in decaying carcasses.

  8. Determining the functional role of waterborne amino acid uptake in hagfish nutrition: a constitutive pathway when fasting or a supplementary pathway when feeding?

    PubMed

    Glover, Chris N; Blewett, Tamzin A; Wood, Chris M

    2016-10-01

    Hagfish are unique among aquatic "vertebrates" in their ability to absorb amino acids directly from the water via skin and gill epithelia, but it is unknown whether this phenomenon extends beyond a few studied substrates; what effect fed state has on absorption; and what functional role this may play in hagfish nutrition. Using in vivo and in vitro transport assays, uptake and tissue distribution of the waterborne amino acids L-alanine, L-lysine, and L-phenylalanine were examined as a function of fed state. All three amino acids were shown to be taken up from the water (lysine and phenylalanine for the first time). Following immersion in radiolabelled solutions for 24 h, phenylalanine was the amino acid that accumulated at the highest levels in almost all tissues, with the highest accumulation noted in red blood cells and bile, followed by gill and liver. In general, tissues of fed hagfish displayed a significantly reduced phenylalanine accumulation compared to tissues of hagfish fasted for 3 weeks. An in vitro assay showed that phenylalanine was transported across the skin at the highest rate, with the uptake of lysine occurring at the lowest rate. Feeding status had no significant effect on in vitro transport. These data indicate that dissolved organic nutrients are a significant source of nutrition to hagfish, and may be relatively more important during periods of fasting than during periods of feeding when immersed in decaying carcasses. PMID:27215782

  9. Enhanced intracellular accumulation of a non-nucleoside anti-cancer agent via increased uptake of its valine ester prodrug through amino acid transporters.

    PubMed

    Kwak, Eun-Young; Shim, Won-Sik; Chang, Ji-Eun; Chong, Saeho; Kim, Dae-Duk; Chung, Suk-Jae; Shim, Chang-Koo

    2012-07-01

    The phenomenon known as multiple-drug resistance, whereby anti-cancer agents are expelled from cancer cells, makes it necessary to develop methods that will reliably increase the accumulation of anti-cancer agents within cancer cells. To accomplish this goal, a new model compound, Val-SN-38, was synthesized by introducing valine to SN-38, an active ingredient of irinotecan. Val-SN-38 improved intracellular accumulation approximately 5-fold in MCF7 cells, compared with SN-38, and rather than changes in membrane permeability, the amino acid transporter ATB(0,+) played a role, whereas the dipeptide transporter PEPT1 did not. Other sodium-dependent amino acid transporters, namely ATA1, ATA2, and ASCT2, were unexpectedly involved in the uptake of Val-SN-38 as well. The efflux of Val-SN-38 by major efflux transporters was variably changed, but not significantly. In summary, the enhanced accumulation of Val-SN-38 in cancer cells was due to augmented uptake via various amino acid transporters. The results of the present study make a compelling argument in favour of a prodrug concept that can improve intracellular accumulation and take advantage of amino acid transporters without significantly inducing multiple-drug resistance.

  10. Acidic retinoids synergize with vitamin A to enhance retinol uptake and STRA6, LRAT, and CYP26B1 expression in neonatal lung.

    PubMed

    Wu, Lili; Ross, A Catharine

    2010-02-01

    Vitamin A (VA) is essential for fetal lung development and postnatal lung maturation. VA is stored mainly as retinyl esters (REs), which may be mobilized for production of retinoic acid (RA). This study was designed 1) to evaluate several acidic retinoids for their potential to increase RE in the lungs of VA-supplemented neonatal rats, and 2) to determine the expression of retinoid homeostatic genes related to retinol uptake, esterification, and catabolism as possible mechanisms. When neonatal rats were treated with VA combined with any one of several acidic retinoids (RA, 9-cis-RA, or Am580, a stable analog of RA), lung RE increased approximately 5-7 times more than after an equal amount of VA alone. Retinol uptake and esterification during the period of absorption correlated with increased expression of both STRA6 (retinol-binding protein receptor) and LRAT (retinol esterification), while a reduction in RE after 12 h in Am580-treated, VA-supplemented rats correlated with a strong and persistent increase in CYP26B1 (RA hydroxylase). We conclude that neonatal lung RE can be increased synergistically by VA combined with both natural and synthetic acidic retinoids, concomitant with induction of the dyad of STRA6 and LRAT. However, the pronounced and prolonged induction of CYP26B1 by Am580 may counteract lung RE accumulation after the absorption process is completed.

  11. Dynamics of the enhanced emissions of monoterpenes and methyl salicylate, and decreased uptake of formaldehyde, by Quercus ilex leaves after application of jasmonic acid.

    PubMed

    Filella, Iolanda; Peñuelas, Josep; Llusià, Joan

    2006-01-01

    Jasmonic acid (JA) is a signalling compound with a key role in both stress and development in plants, and is reported to elicit the emission of volatile organic compounds (VOCs). Here we studied the dynamics of such emissions and the linkage with photosynthetic rates and stomatal conductance. We sprayed JA on leaves of the Mediterranean tree species Quercus ilex and measured the photosynthetic rates, stomatal conductances, and emissions and uptake of VOCs using proton transfer reaction mass spectrometry and gas chromatography after a dark-light transition. Jasmonic acid treatment delayed the induction of photosynthesis and stomatal conductance by approx. 20 min, and decreased them 24 h after spraying. Indications were found of both stomatal and nonstomatal limitations of photosynthesis. Monoterpene emissions were enhanced (20-30%) after JA spraying. Jasmonic acid also increased methyl salicylate (MeSa) emissions (more than twofold) 1 h after treatment, although after 24 h this effect had disappeared. Formaldehyde foliar uptake decreased significantly 24 h after JA treatment. Both biotic and abiotic stresses can thus affect plant VOC emissions through their strong impact on JA levels. Jasmonic acid-mediated increases in monoterpene and MeSa emissions might have a protective role when confronting biotic and abiotic stresses. PMID:16390425

  12. A local renal renin-angiotensin system activation via renal uptake of prorenin and angiotensinogen in diabetic rats.

    PubMed

    Tojo, Akihiro; Kinugasa, Satoshi; Fujita, Toshiro; Wilcox, Christopher S

    2016-01-01

    The mechanism of activation of local renal renin-angiotensin system (RAS) has not been clarified in diabetes mellitus (DM). We hypothesized that the local renal RAS will be activated via increased glomerular filtration and tubular uptake of prorenin and angiotensinogen in diabetic kidney with microalbuminuria. Streptozotocin (STZ)-induced DM and control rats were injected with human prorenin and subsequently with human angiotensinogen. Human prorenin uptake was increased in podocytes, proximal tubules, macula densa, and cortical collecting ducts of DM rats where prorenin receptor (PRR) was expressed. Co-immunoprecipitation of kidney homogenates in DM rats revealed binding of human prorenin to the PRR and to megalin. The renal uptake of human angiotensinogen was increased in DM rats at the same nephron sites as prorenin. Angiotensin-converting enzyme was increased in podocytes, but decreased in the proximal tubules in DM rats, which may have contributed to unchanged renal levels of angiotensin despite increased angiotensinogen. The systolic blood pressure increased more after the injection of 20 μg of angiotensinogen in DM rats than in controls, accompanied by an increased uptake of human angiotensinogen in the vascular endothelium. In conclusion, endocytic uptake of prorenin and angiotensinogen in the kidney and vasculature in DM rats was contributed to increased tissue RAS and their pressor response to angiotensinogen.

  13. Exceptional gravimetric and volumetric CO2 uptake in a palladated NbO-type MOF utilizing cooperative acidic and basic, metal-CO2 interactions.

    PubMed

    Spanopoulos, I; Bratsos, I; Tampaxis, C; Vourloumis, D; Klontzas, E; Froudakis, G E; Charalambopoulou, G; Steriotis, T A; Trikalitis, P N

    2016-08-18

    A novel NbO-type MOF is reported based on a palladated organic linker, showing a remarkable gravimetric and volumetric CO2 uptake, reaching 201.8 cm(3) g(-1) (9.0 mmol g(-1), 39.7 wt%) and 187.8 cm(3) cm(-3) at 273 K and 1 bar, respectively. Accurate theoretical calculations revealed that the exceptional CO2 uptake is due to the combination of Lewis base Pd(ii)-CO2 (24.3 kJ mol(-1)) and Lewis acid Cu(ii)-CO2 (30.3 kJ mol(-1)) interactions, as well as synergistic pore size effects. PMID:27498783

  14. Behavior and impact of zirconium in the soil-plant system: plant uptake and phytotoxicity.

    PubMed

    Shahid, Muhammad; Ferrand, Emmanuel; Schreck, Eva; Dumat, Camille

    2013-01-01

    Zirconium (Zr) is a transition metal that has both stable and radioactive isotopes.This metal has gained significant attention as a major pollutant of concern, partly because it has been prominent in the debate concerning the growing anthropogenic pressure on the environment. Its numerous past and present uses have induced significant soil and water pollution. Zr is generally considered to have low mobility in soils. The behavior of Zr particularly depends on the characteristics of the media in which it exists, and even its presence in the biosphere as a contaminate may affect its behavior. In this chapter, we describe the relationship between the behavior of Zrand its speciation in soils, its uptake and accumulation by plants, its translocation and toxicity inside plants, and mechanisms by which plants detoxify it.Zr is abundant and occurs naturally in the earth's crust. Zr emissions to the atmosphere are increasing from anthropogenic activities such as its use in industry and nuclear reactors. Zr forms various complexes with soil components, which reduces its soil mobility and phytoavailabilty. The mobility and phytoavailabilty of Zr in soil depend on its speciation and the physicochemical properties of soil that include soil pH, texture, and organic contents. Despite having low soil mobility and phytoavailability,amounts of Zr are absorbed by plants, mainly through the root system and can thereby enter the food chain.After plant uptake, Zr mainly accumulates in root cells. Zr does not have any known essential function in plant or animal metabolism. Although little published data are available, we conclude that the phytotoxicity of Zr is generally low.Notwithstanding, Zr can significantly reduce plant growth and can affect plantenzyme activity. When exposed to Zr-induced toxicity, plants possess numerous defense mechanisms to cope with the toxicity. Such strategies include Zr sequestration in plant roots and activation of various antioxidants. Because Zr may have

  15. Stealth CD44-targeted hyaluronic acid supramolecular nanoassemblies for doxorubicin delivery: probing the effect of uncovalent pegylation degree on cellular uptake and blood long circulation.

    PubMed

    Han, Xiaopeng; Li, Zhenbao; Sun, Jin; Luo, Cong; Li, Lin; Liu, Yuhai; Du, Yuqian; Qiu, Shuhong; Ai, Xiaoyu; Wu, Chunnuan; Lian, He; He, Zhonggui

    2015-01-10

    Stealth active targeting nanoparticles (NPs) usually include two types of ligand sites: ligand anchored on distal ends of the polyethylene glycol (PEG) and ligand buried under pegylated layer. The latter typical case is hyaluronic acid (HA)-based NPs; however, there is little information available for the latter NPs about effect of the optimal density of surface PEG coating on the blood circulation time, cellular uptake and in vivo anticancer activity. Thus, in this study, in order to optimize the anticancer effects of HA-based NPs, we focus on how uncovalent pegylation degree modulates blood circulation time and cellular uptake of HA-based NPs. We firstly designed a new double-hydrophilic copolymer by conjugating HP-β-cyclodextrin with HA, and this carrier was further pegylated with adamantyl-peg (ADA-PEG) to form inclusion complex HA-HPCD/ADA-PEG, termed as HCPs. The supramolecular nanoassemblies were fabricated by host-guest and polar interactions between HCPs and doxorubicin (Dox), with vitamin E succinate (VES) being a nanobridge. Despite the active recognition between HA and CD44 receptor, the cellular uptake and targeting efficiency of HA-NPs decreased with the increasing peg density, demonstrating HA was partly buried by high density peg coating. However, the high density of peg coating was beneficial to long circulation time, tumor biodistribution and anticancer activity in vivo. NPs with 5% peg coating had the optimal cellular targeting efficiency in vitro and anticancer effects in vivo. The findings suggest that balancing long circulation property and cellular uptake is important to achieve the optimal antitumor efficacy for pegylated HA-based NPs, and that PEG coating densities cannot be extended beyond a certain density for shielding effect without compromising the efficacy of hyaluronic acid targeted delivery.

  16. 21 CFR 862.1795 - Vanilmandelic acid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vanilmandelic acid test system. 862.1795 Section... Systems § 862.1795 Vanilmandelic acid test system. (a) Identification. A vanilmandelic acid test system is a device intended to measure vanilmandelic acid in urine. Measurements of vanilmandelic...

  17. Relationship between lead uptake by lettuce and water-soluble low-molecular-weight organic acids in rhizosphere as influenced by transpiration.

    PubMed

    Liao, Yuan Chung; Chang Chien, Shui-Wen; Wang, Min-Chao; Shen, Yuan; Seshaiah, Kalluru

    2007-10-17

    The relationship between Pb uptake by leaf lettuce ( Lactuca sativa L.) and water-soluble low-molecular-weight organic acids (LMWOAs) in rhizosphere, as influenced by transpiration (high and low), has been studied. Studies were carried out by culturing lettuce plants grown for 2 weeks in pots filled with quartz sand mixed with anion-exchange resin and then for 30 days in a greenhouse. The potted lettuce plants were subjected to stress by the addition of Pb(NO 3) 2 solutions (100, 200, and 300 mg of Pb L (-1)) and by high and low transpiration treatments for another 10-day period. Blank experiments (without addition of Pb(NO 3) 2 solutions to the pots) were also run. There were no significant differences in the growth of the plants with the addition of Pb(NO 3) 2 solutions in either of the transpirations studies. Uptake of Pb by the shoots and roots of the plants was found to be proportional to the concentration of Pb solutions added, and more accumulation was observed in the roots than in the shoots at the end of days 3 and 10. High transpiration caused more Pb uptake than did low transpiration. One volatile acid (propionic acid) and nine nonvolatile acids (lactic, glycolic, oxalic, succinic, fumaric, oxalacetic, d-tartaric, trans-aconitic, and citric acids) in rhizosphere quartz sand or anion-exchange resin were identified and quantified by gas chromatography analysis with a flame ionization detector. The amount of LMWOAs in rhizosphere quartz sand or anion-exchange resin increased with higher amounts of Pb in quartz sand solution and also with longer duration of the study. The total quantities of the LMWOAs in the rhizosphere quartz sand or anion-exchange resin were significantly higher under high and low transpiration with a 300 mg of Pb L (-1) solution addition at the end of day 10. Compared with our previous related studies (published work), the present study shows that the presence of LMWOAs in rhizosphere does not significantly affect Pb uptake by lettuce

  18. CONTINUOUS, AUTOMATED AND SIMULTANEOUS MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE EVOLUTION IN BIOLOGICAL SYSTEMS

    EPA Science Inventory

    Commercial respirometers are capable of continuously and automatically measuring oxygen uptake in bioreactors. A method for continuously and automatically measuring carbon dioxide evolution can be retrofitted to commercial respirometers. Continuous and automatic measurements of...

  19. Salicylic acid alleviates aluminum toxicity in rice seedlings better than magnesium and calcium by reducing aluminum uptake, suppressing oxidative damage and increasing antioxidative defense.

    PubMed

    Pandey, Poonam; Srivastava, Rajneesh Kumar; Dubey, R S

    2013-05-01

    Aluminum toxicity is a major constraint to crop production in acid soils. The present study was undertaken to examine the comparative ameliorating effects of salicylic acid, Ca and Mg on Al toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Al treatment (0.5 mM AlCl3) caused decrease in plant vigour, loss of root plasma membrane integrity, increased contents of O 2 (∙-) , H2O2, lipid peroxidation, protein carbonyls and decline in the level of protein thiol. Al treatment caused significant changes in activity of antioxidative enzymes in rice seedlings. Exogenously added salicylic acid (60 μM), Ca (1 mM) and Mg (0.25 mM) significantly alleviated Al toxicity effects in the seedlings marked by restoration of growth, suppression of Al uptake, restoration of root plasma membrane integrity and decline in O 2 (∙-) , H2O2, lipid peroxidation and protein carbonyl contents. Salicylic acid, Ca and Mg suppressed Al-induced increase in SOD, GPX and APX activities while it elevated Al-induced decline in CAT activity. By histochemical staining of O 2 (∙-) using NBT and H2O2 using DAB, it was further confirmed that added salicylic acid, Ca or Mg decreased Al-induced accumulation of O 2 (∙-) and H2O2 in the leaf tissues. Results indicate that exogenously added salicylic acid, Ca or Mg alleviates Al toxicity in rice seedlings by suppressing Al uptake, restoring root membrane integrity, reducing ROS level and ROS induced oxidative damage and regulating the level of antioxidative enzyme activities. Further salicylic appears to be superior to Mg and Ca in alleviating Al toxicity effects in rice plants.

  20. Diversity of siderophore-mediated iron uptake systems in fluorescent pseudomonads: not only pyoverdines.

    PubMed

    Cornelis, Pierre; Matthijs, Sandra

    2002-12-01

    Fluorescent pseudomonads are gamma-proteobacteria known for their capacity to colonize various ecological niches. This adaptability is reflected by their sophisticated and diverse iron uptake systems. The majority of fluorescent pseudomonads produce complex peptidic siderophores called pyoverdines or pseudobactins, which are very efficient iron scavengers. A tremendous variety of pyoverdines has been observed, each species producing a different pyoverdine. This variety can be used as an interesting tool to study the diversity and taxonomy of fluorescent pseudomonads. Other siderophores, including newly described ones, are also produced by pseudomonads, sometimes endowed with interesting properties in addition to iron scavenging, such as formation of complexes with other metals or antimicrobial activity. Factors other than iron limitation, and different regulatory proteins also seem to influence the production of siderophores in pseudomonads and are reviewed here as well. Another peculiarity of pseudomonads is their ability to use a large number of heterologous siderophores via different TonB-dependent receptors. A first genomic analysis of receptors in four different fluorescent pseudomonads suggests that their siderophore ligand repertoire is likely to overlap, and that not all receptors recognize siderophores as ligands. PMID:12534462

  1. Impacts of carbon source addition on denitrification and phosphorus uptake in enhanced biological phosphorus removal systems.

    PubMed

    Begum, Shamim A; Batista, Jacimaria R

    2013-01-01

    In this study, simultaneous denitrification and phosphorus (P) removal were investigated in batch tests using nitrified mixed liquor and secondary wastewater influent from a full-scale treatment plant and different levels of acetate and propionate as supplemental carbon sources. Without supplemental carbon source, denitrification occurred at low rate and P release and P uptake was negatively affected (i.e., P removal of only 59.7%). When acetate and propionate were supplied, denitrification and P release occurred simultaneously under anoxic conditions. For acetate and propionate at a C/N stoichiometric ratio of 7.6, P release was negatively affected by denitrification. For acetate, the percent P removal and denitrification were very similar for C/N ratios of 22 (5X stoichiometric) and 59 (10X stoichiometric). For propionate, both percent P removal and denitrification deteriorated for C/N ratios of 22 (5X stoichiometric) and 45 (10X stoichiometric). It was observed that carbon source added in excess to stoichiometric ratio was consumed in the aerobic zone, but P was not taken up. This implies that PAO bacteria may utilize the excess carbon source in the aerobic zone rather than their polyhydroxyalkanoate (PHA) reserves, thereby promoting deterioration of the system.

  2. Nnuclear uptake and retention of a synthetic progestin in the cardiovascular system of the baboon

    SciTech Connect

    Sheridan, P.J.; McGill, H.C. Jr.

    1984-06-01

    It has long been known that there is a sexual dimorphism in the incidence of coronary heart disease. This observation, together with more recent reports of increased cardiovascular disease associated with the use of oral contraceptives, led to a search for steroid receptors in the cardiovascular system. In this study the nuclear uptake and retention of a synthetic progestin was examined in the cardiovascular system of the baboons. Long term oophorectomized baboons were primed with estradiol benzoate for 3 days before the experiment (50 micrograms/kg, im) and adrenalectomized 2 days before the experiment. On the day of the experiment, the animals were injected under anesthesia with 2.5 micrograms/kg BW (/sup 3/H)ORG 2058 (16 alpha-ethyl-21-hydroxy-19-nor-(6,7-/sup 3/H)pregn-4-ene-3,20-dione) or with (/sup 3/H) ORG 2058 plus a 1000-fold excess of unlabeled progesterone (control). One hour after the injection, the animals were rapidly exsanguinated, and parts of the cardiovascular system were removed and processed for autoradiography. Localization of the synthetic progestin was found in nuclei of between 25-75% of all smooth muscle cells of the media of all arteries examined and to a lesser extent in the nuclei of the fibroblasts and others cells of the adventitia. Localization of the synthetic progestin in the heart was limited to approximately 1% of the myocardial cells and less than 5% of interstitial cell nuclei. The pattern of localization found differs from that for estrogen and androgen and suggests the possible presence of estrogen-independent progesterone receptors in smooth muscle cells of the media of the aorta and coronary arteries.

  3. Secondary Organic Aerosol Formation from 2-Methyl-3-Buten-2-ol Photooxidation: Evidence of Acid-Catalyzed Reactive Uptake of Epoxides

    SciTech Connect

    Zhang, Haofei; Zhang, Zhenfa; Cui, Tianqu; Lin, Ying-Hsuan; Bhathela, Neil A.; Ortega, John; Worton, David; Goldstein, Allen H.; Guenther, Alex B.; Jimenez, Jose L.; Gold, Avram; Surratt, Jason D.

    2014-04-08

    Secondary organic aerosol (SOA) formation from 2-methyl-3-buten-2-ol (MBO) photooxidation has recently been observed in both field and laboratory studies. Similar to isoprene, MBO-derived SOA increases with elevated aerosol acidity in the absence of nitric oxide; therefore, an epoxide intermediate, (3,3-dimethyloxiran-2-yl)methanol (MBO epoxide) was synthesized and tentatively proposed here to explain this enhancement. In the present study, the potential of the synthetic MBO epoxide to form SOA via reactive uptake was systematically examined. SOA was observed only in the presence of acidic aerosols. Major SOA constituents, 2,3-dihydroxyisopentanol (DHIP) and MBO-derived organosulfate isomers, were chemically characterized in both laboratory-generated SOA and in ambient fine aerosols collected from the BEACHON-RoMBAS field campaign during summer 2011, where MBO emissions are substantial. Our results support epoxides as potential products of MBO photooxidation leading to formation of atmospheric SOA and suggest that reactive uptake of epoxides may generally explain acid enhancement of SOA observed from other biogenic hydrocarbons.

  4. Stimulation of cartilage amino acid uptake by growth hormone-dependent factors in serum. Mediation by adenosine 3':5'-monophosphate.

    PubMed

    Drezner, M K; Eisenbarth, G S; Neelon, F A; Lebovitz, H E

    1975-02-13

    The effects of growth hormone-dependent serum factors on amino acid transport and on cartilage cyclic AMP levels in embryonic chicken cartilage were studied in vitro. Cartilages incubated in medium containing rat serum showed a significantly greater uptake of alpha-amino [1-14C] isobutyrate or [1-14C] cycloleucine than control cartilages incubated in medium alone. Normal rat serum (5%) added to the incubation medium also caused an increase in cartilage cyclic AMP content (from as little as 23% to as much as 109%). The factors in serum which increase cartilage cyclic AMP and amino acid uptake are growth hormone dependent, since neither growth hormone itself nor serum from hypophysectomized rats restores these serum factors. Studies comparing the ability of sera with varying amounts of growth hormone-dependent factors to stimulate amino-aminoisobutyrate transport and to increase cartilage cyclic AMP show a striking linear correlation between the two effects (r=0.977). Theophylline and prostaglandin E1, WHICH RAISE CARTILAGE CYCLIC AMP also increase amino-aminoisobutyrate transport. Exogenous cyclic AMP, N6-monobutyryl cyclic AMP and n6, 02'-dibutyryl cyclic AMP increase cartilage amino-aminoisobutyrate transport. The data are compatible with the thesis that growth hormone-dependent serum factors increase cartilage amino acid transport by elevating cartilage cyclic AMP.

  5. Exposure to bioaccumulative organochlorine compounds alters adipogenesis, fatty acid uptake, and adipokine production in NIH3T3-L1 cells.

    PubMed

    Howell, George; Mangum, Lauren

    2011-02-01

    Exposure to the organochlorine compounds p,p'-dichlorodiphenyldichloroethylene (DDE) and oxychlordane have been associated with an increased prevalence of diabetes. Although the exact etiology of diabetes, especially type 2 diabetes, is not known, it is thought that adipose dysfunction plays a vital role in the progression of this disease. Thus, the present study examined whether exposure to these bioaccumulative compounds promotes adipocyte dysfunction including alterations in adipogenesis, fatty acid storage, and adipokine production within the adipocyte. We employed the NIH3T3-L1 cell line as a model for adipogenesis and mature adipocyte function. Exposure to DDE or oxychlordane prior to and throughout differentiation did not affect adipogenesis. In mature NIH3T3-L1 adipocytes, exposure to oxychlordane, DDE, or dieldrin had no effect on insulin-stimulated fatty acid uptake but did increase basal fatty acid uptake over a 24 h period. There was no observed effect of exposure to these compounds on lipolysis. Exposure to DDE significantly increased the release of leptin, resistin, and adiponectin from mature adipocytes with corresponding increases in expression of resistin and adiponectin. Taken together, the current data suggest that exposure to these compounds, especially DDE, may promote some aspects of adipocyte dysfunction that are commonly associated with obesity and type 2 diabetes.

  6. Endotoxin-stimulated macrophages decrease bile acid uptake in WIF-B cells, a rat hepatoma hybrid cell line.

    PubMed

    Sturm, E; Zimmerman, T L; Crawford, A R; Svetlov, S I; Sundaram, P; Ferrara, J L; Karpen, S J; Crawford, J M

    2000-01-01

    Endotoxemia leads to cytokine-mediated alterations of the hepatocellular sodium-taurocholate-cotransporting polypeptide (ntcp). We hypothesized that stimulated macrophages are essential transducers for down-regulating hepatocellular bile salt uptake in response to endotoxin (lipopolysaccharide [LPS]) exposure. Using an in vitro model, we exposed mouse macrophages (IC-21 cell line) to LPS for 24 hours. Concentrations of cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6 increased 10.6-fold, 12.5-fold, and 444-fold, respectively, in LPS-conditioned IC-21 medium (CM) versus unconditioned IC-21 medium (UM). WIF-B rat hepatoma hybrid cells were incubated with either CM or UM or treated directly with medium containing recombinant TNF-alpha, IL-1beta, and IL-6. [(3)H]Taurocholate ([(3)H]TC) uptake decreased in WIF-B cells exposed to either TNF-alpha (54% of control), IL-1beta (78%), IL-6 (55%) as single additives, or in triple combination (TCC) (43%). A virtually identical decrease was observed after exposing WIF-B cells to CM (52%, P <.001). LPS had no direct effect on [(3)H]TC uptake. CM treatment did not decrease L-alanine transport in WIF-B cells. Blocking antibodies against TNF-alpha, IL-1beta, and IL-6 restored the diminished [(3)H]TC uptake in cells exposed to TCC and CM to 87% and 107% of controls, respectively. Northern blotting revealed that ntcp messenger RNA (mRNA) expression was significantly reduced in WIF-B cells after exposure to CM, and in primary rat hepatocytes exposed to CM or TNF-alpha (68%, 14%, and 29% of control, respectively). We conclude that macrophages and their ability to secrete the cytokines TNF-alpha, IL-1beta, and IL-6 may be essential in mediating the endotoxin-induced cholestatic effect of decreased hepatocellular bile salt uptake. PMID:10613737

  7. Acid mine water aeration and treatment system

    DOEpatents

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  8. Similar specificities of symbiont uptake by adults and larvae in an anemone model system for coral biology.

    PubMed

    Hambleton, Elizabeth A; Guse, Annika; Pringle, John R

    2014-05-01

    Reef-building corals depend for much of their energy on photosynthesis by symbiotic dinoflagellate algae (genus Symbiodinium) that live within their gastrodermal cells. However, the cellular mechanisms underpinning this ecologically critical symbiosis, including those governing the specificity of symbiont uptake by the host, remain poorly understood, in part because of the difficulties of working with corals in the laboratory. Here, we used the small symbiotic sea anemone Aiptasia as an experimentally tractable model system to analyze the specificity and timing of symbiosis onset in larval and adult animals under controlled laboratory conditions. Using four clonal, axenic Symbiodinium strains, we found no difference in uptake specificity between larvae (even when very young) and adults. Although both compatible and incompatible algal strains were found within the larval guts, only the former appeared to be internalized by gastrodermal cells, and they (but not incompatible algae) proliferated rapidly within the larvae in the absence of detectable exchange with other larvae. Older larvae showed reduced ingestion of both compatible and incompatible algae, and the addition of food failed to promote the uptake of an incompatible algal strain. Thus, Aiptasia adults and larvae appear to have similar mechanisms for discriminating between compatible and incompatible dinoflagellate types prior to phagocytosis by host gastrodermal cells. Whether a particular algal strain is compatible or incompatible appears to be stable during years of axenic culture in the absence of a host. These studies provide a foundation for future analyses of the mechanisms of symbiont-uptake specificity in this emerging model system. PMID:24526722

  9. Poly-(lactic-co-glycolic-acid)-based particulate vaccines: particle uptake by dendritic cells is a key parameter for immune activation.

    PubMed

    Silva, A L; Rosalia, R A; Varypataki, E; Sibuea, S; Ossendorp, F; Jiskoot, W

    2015-02-11

    Poly(lactic-co-glycolic acid) (PLGA) particles have been extensively studied as biodegradable delivery system to improve the potency and safety of protein-based vaccines. In this study we analyzed how the size of PLGA particles, and hence their ability to be engulfed by dendritic cells (DC), affects the type and magnitude of the immune response in comparison to sustained release from a local depot. PLGA microparticles (MP, volume mean diameter≈112 μm) and nanoparticles (NP, Z-average diameter≈350 nm) co-encapsulating ovalbumin (OVA) and poly(I:C), with comparable antigen (Ag) release characteristics, were prepared and characterized. The immunogenicity of these two distinct particulate vaccines was evaluated in vitro and in vivo. NP were efficiently taken up by DC and greatly facilitated MHC I Ag presentation in vitro, whereas DC cultured in the presence of MP failed to internalize significant amounts of Ag and hardly showed MHC I Ag presentation. Vaccination of mice with NP resulted in significantly better priming of Ag-specific CD8(+) T cells compared to MP and OVA emulsified with incomplete Freund's adjuvant (IFA). Moreover, NP induced a balanced TH1/TH2-type antibody response, compared to vaccinations with IFA which stimulated a predominant TH2-type response, whereas MP failed to increase antibody titers. In conclusion, we postulate that particle internalization is of crucial importance and therefore particulate vaccines should be formulated in the nano- but not micro-size range to achieve efficient uptake, significant MHC class I cross-presentation and effective T and B cell responses.

  10. Cellular uptake and anticancer activity of salvianolic acid B phospholipid complex loaded nanoparticles in head and neck cancer and precancer cells.

    PubMed

    Li, Hongquan; Shi, Linjun; Wei, Jie; Zhang, Chenping; Zhou, Zengtong; Wu, Lan; Liu, Wei

    2016-11-01

    Salvianolic acid B (SalB) was demonstrated to be a promising chemopreventive agent for head and neck squamous cell carcinoma (HNSCC) in the previous studies by our and other research institution, but the properties like low efficacy, poor systemic delivery, and low bioavailability has hampered its clinical applications. To continue our research program focused on the use of natural compounds on cancer chemoprevention, we propose a first example of phospholipid complex loaded nanoparticles (PLC-NPs) encapsulating SalB as a potential carrier for intervention of HNSCC (HN13, HN30) cells and precancer Leuk1 cells in this study. Qualitative and quantitive studies of cellular uptake showed that intracellular accumulation of SalB was significantly higher when HN13, HN30 and Leuk1 cells were incubated with SalB-PLC-NPs complex (nano-SalB) as against free-SalB. Cell viability assay revealed that the cell growth of HN13 and HN30 cells was significantly inhibited of 56.1% and 29.3%, respectively, for nano-SalB compared to an equivalent amount of free-SalB (P<0.001). Moreover, cell cycle and apoptosis assay showed that a clear trend of cell cycle arrest and induction of apoptosis was also observed within the HNSCC cells treated with nano-SalB. Collectively, this study demonstrated that nano-SalB was significantly more potent had an anticancer effect against HNSCC cells, which serves as the first step toward establishing SalB nano-formulations as promising cancer chemopreventive agents. The current study could pave a new way for the development of drugs that target HNSCC in the future.

  11. A multicellular, neuro-mimetic model to study nanoparticle uptake in cells of the central nervous system.

    PubMed

    Fernandes, A R; Chari, D M

    2014-09-01

    Evaluating the uptake and handling of biomedically relevant nanoparticles by cells of the nervous system critically underpins the effective use of nanoparticle platforms for neuro-regenerative therapies. The lack of biologically relevant and 'neuromimetic' models for nanomaterials testing (that can simulate the cellular complexity of neural tissue) currently represents a bottleneck. Further, propagation of individual cell types, in different neural cell-specific media (as commonly occurs in the nanotechnology field), can result in non-standardised corona formation around particles, confounding analyses of intercellular differences between neural cells in nanoparticle uptake. To address these challenges, we have developed a facile multicellular model that broadly simulates the ratios of neurons, astrocytes and oligodendrocytes found in vivo. All cell types in the model are derived from a single neural stem cell source, and propagated in the same medium overcoming the issue of variant corona formation. Using a fluorescent transfection-grade magnetic particle (MP), we demonstrate dramatic differences in particle uptake and resultant gene transfer between neural cell subtypes, with astrocytes being the dominant population in terms of particle uptake and transfection. We demonstrate the compatibility of the model with a high resolution scanning electron microscopy technique, allowing for membrane features of MP stimulated cells to be examined. Using this approach, astrocytes displayed high membrane activity in line with extensive particle uptake/transfection, relative to neurons and oligodendrocytes. We consider that the stem cell based model described here can provide a simple and versatile tool to evaluate interactions of neural cells with nanoparticle systems developed for neurological applications. Models of greater complexity can be evolved from this basic system, to further enhance its neuromimetic capacity.

  12. Functional expression cloning and characterization of the hepatocyte Na+/bile acid cotransport system.

    PubMed Central

    Hagenbuch, B; Stieger, B; Foguet, M; Lübbert, H; Meier, P J

    1991-01-01

    Liver parenchymal cells continuously extract high amounts of bile acids from portal blood plasma. This uptake process is mediated by a Na+/bile acid cotransport system. A cDNA encoding the rat liver bile acid uptake system has been isolated by expression cloning in Xenopus laevis oocytes. The cloned transporter is strictly sodium-dependent and can be inhibited by various non-bile-acid organic compounds. Sequence analysis of the cDNA revealed an open reading frame of 1086 nucleotides coding for a protein of 362 amino acids (calculated molecular mass 39 kDa) with five possible N-linked glycosylation sites and seven putative transmembrane domains. Translation experiments in vitro and in oocytes indicate that the transporter is indeed glycosylated and that its polypeptide backbone has an apparent molecular mass of 33-35 kDa. Northern blot analysis with the cloned probe revealed crossreactivity with mRNA species from rat kidney and intestine as well as from liver tissues of mouse, guinea pig, rabbit, and man. Images PMID:1961729

  13. Spexin is a Novel Human Peptide that Reduces Adipocyte Uptake of Long Chain Fatty Acids and Causes Weight Loss in Rodents with Diet-induced Obesity*

    PubMed Central

    Walewski, José L.; Ge, Fengxia; Lobdell, Harrison; Levin, Nancy; Schwartz, Gary J.; Vasselli, Joseph; Pomp, Afons; Dakin, Gregory; Berk, Paul D.

    2014-01-01

    Objective Microarray studies identified Ch12:orf39 (Spexin) as the most dysregulated gene in obese human fat. Therefore we examined its role in obesity pathogenesis. Design and Methods Spexin effects on food intake, meal patterns, body weight, Respiratory Exchange Ratio (RER), and locomotor activity were monitored electronically in C57BL/6J mice or Wistar rats with dietary-induced obesity (DIO). Its effects on adipocyte [3H]-oleate uptake were determined. Results In humans, Spexin gene expression was down-regulated 14.9-fold in obese omental and subcutaneous fat. Circulating Spexin changed in parallel, correlating (r = −0.797) with Leptin. In rats, Spexin (35 μg/kg/day s.c) reduced caloric intake ~32% with corresponding weight loss. Meal patterns were unaffected. In mice, Spexin (25 μg/kg/day i.p.) significantly reduced the RER at night, and increased locomotion. Spexin incubation in vitro significantly inhibited facilitated fatty acid (FA) uptake into DIO mouse adipocytes. Conditioned taste aversion testing (70μg/kg/day i.p.) demonstrated no aversive Spexin effects. Conclusions Spexin gene expression is markedly down-regulated in obese human fat. The peptide produces weight loss in DIO rodents. Its effects on appetite and energy regulation are presumably central; those on adipocyte FA uptake appear direct and peripheral. Spexin is a novel hormone involved in weight regulation, with potential for obesity therapy. PMID:24550067

  14. 21 CFR 862.1509 - Methylmalonic acid (nonquantitative) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Test Systems § 862.1509 Methylmalonic acid (nonquantitative) test system. (a) Identification. A methylmalonic acid (nonquantitative) test system is a device intended to identify methylmalonic acid in urine... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Methylmalonic acid (nonquantitative) test...

  15. 21 CFR 862.1509 - Methylmalonic acid (nonquantitative) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Test Systems § 862.1509 Methylmalonic acid (nonquantitative) test system. (a) Identification. A methylmalonic acid (nonquantitative) test system is a device intended to identify methylmalonic acid in urine... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Methylmalonic acid (nonquantitative) test...

  16. 21 CFR 862.1509 - Methylmalonic acid (nonquantitative) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Test Systems § 862.1509 Methylmalonic acid (nonquantitative) test system. (a) Identification. A methylmalonic acid (nonquantitative) test system is a device intended to identify methylmalonic acid in urine... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Methylmalonic acid (nonquantitative) test...

  17. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Uric acid test system. 862.1775 Section 862.1775....1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to measure uric acid in serum, plasma, and urine. Measurements obtained by this device are used in the...

  18. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Uric acid test system. 862.1775 Section 862.1775....1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to measure uric acid in serum, plasma, and urine. Measurements obtained by this device are used in the...

  19. Genetic identification of ACC-RESISTANT2 reveals involvement of LYSINE HISTIDINE TRANSPORTER1 in the uptake of 1-aminocyclopropane-1-carboxylic acid in Arabidopsis thaliana.

    PubMed

    Shin, Kihye; Lee, Sumin; Song, Won-Yong; Lee, Rin-A; Lee, Inhye; Ha, Kyungsun; Koo, Ja-Choon; Park, Soon-Ki; Nam, Hong-Gil; Lee, Youngsook; Soh, Moon-Soo

    2015-03-01

    1-Aminocyclopropane-1-carboxylic acid (ACC) is a biosynthetic precursor of ethylene, a gaseous plant hormone which controls a myriad of aspects of development and stress adaptation in higher plants. Here, we identified a mutant in Arabidopsis thaliana, designated as ACC-resistant2 (are2), displaying a dose-dependent resistance to exogenously applied ACC. Physiological analyses revealed that mutation of are2 impaired various aspects of exogenous ACC-induced ethylene responses, while not affecting sensitivity to other plant hormones during seedling development. Interestingly, the are2 mutant was normally sensitive to gaseous ethylene, compared with the wild type. Double mutant analysis showed that the ethylene-overproducing mutations, eto1 or eto3, and the constitutive ethylene signaling mutation, ctr1 were epistatic to the are2 mutation. These results suggest that the are2 mutant is not defective in ethylene biosynthesis or ethylene signaling per se. Map-based cloning of ARE2 demonstrated that LYSINE HISTIDINE TRANSPORTER1 (LHT1), encoding an amino acid transporter, is the gene responsible. An uptake experiment with radiolabeled ACC indicated that mutations of LHT1 reduced, albeit not completely, uptake of ACC. Further, we performed an amino acid competition assay and found that two amino acids, alanine and glycine, known as substrates of LHT1, could suppress the ACC-induced triple response in a LHT1-dependent way. Taken together, these results provide the first molecular genetic evidence supporting that a class of amino acid transporters including LHT1 takes part in transport of ACC, thereby influencing exogenous ACC-induced ethylene responses in A. thaliana. PMID:25520403

  20. Gibberellic acid (GA3) enhance seed water uptake, germination and early seedling growth in sugar beet under salt stress.

    PubMed

    Jamil, Muhammad; Rha, Eui Shik

    2007-02-15

    The study was carried out to assess whether water uptake could be improved in sugar beet seeds and salt tolerance at the germination and early seedling stage by soaking the seeds for 10 h in distilled water (control), 100, 150 and 200 mg L(-1) GA3. Electrical Conductivity (EC) values of the NaCl solution were 0.0 (control), 4.7, 9.4 and 14.1 dS n(-1) NaCl. Priming increased the final germination percentage and the germination rate (1/t 50, where t 50 is the time to 50% of germination) under saline condition. Water uptake of primed seeds also increased significantly with increasing concentration of GA3 as compared to control. Priming also alleviated the adverse effect of salt stress on sugar beet in terms of roots and shoots lengths and fresh weights of plants, roots and shoots.

  1. The effect of gestational age on expression of genes involved in uptake, trafficking and synthesis of fatty acids in the rat placenta.

    PubMed

    Rodríguez-Cruz, Maricela; González, Raúl Sánchez; Maldonado, Jorge; López-Alarcón, Mardia; Bernabe-García, Mariela

    2016-10-15

    Gestation triggers a tight coordination among maternal tissues to provide fatty acids (FA) to the fetus through placental transport; however, there is insufficient evidence regarding regulation of proteins involved in placental transport of FA according to gestational age. The aim of this study was to determine the role of gestational age on the expression of genes involved in FA uptake, trafficking and synthesis in the rat placenta to support fetal demands. Gene expression of encoding proteins for placental transport and synthesis of FA was measured in placenta. Also, FA composition was measured in placenta, fetuses and newborns. mRNA expression of lipoprotein lipase (lpl) and fatp-1 (for uptake) was 4.4- and 1.43-fold higher, respectively, during late gestation than at P14, but expression of p-fabp-pm decreased 0.37-fold at late pregnancy in comparison with P14. Only mRNA fabp-4 member for trafficking of FA was 2.95-fold higher at late gestation than at P14. mRNA of fasn and elovl-6 participating in saturated FA and enzymes for the polyunsaturated FA synthesis were downregulated during late gestation and their regulator srebf-1c increased at P16. This study suggests that gestational age has an effect on expression of some genes involved in uptake, trafficking and synthesis of FA in the rat placenta; mRNA expression of lpl and, fatp-1 for uptake and fabp-4 implicated in trafficking was expressed at high levels at late gestation. In addition, placenta expresses the mRNAs involved in FA synthesis; these genes were expressed at low levels at late gestation. Additionally, mRNAs of Srebf-1c transcriptional regulator of desaturases and elongases was highly expressed during late gestation. Finally, these changes in the rat placenta allowed the placenta to partially supply saturated and monounsaturated FA to the fetus.

  2. An Efficient Biodelivery System for Antisense Polyamide Nucleic Acid (PNA)

    PubMed Central

    Mehiri, Mohamed; Upert, Gregory; Tripathi, Snehlata; Di Giorgio, Audrey; Condom, Roger

    2008-01-01

    With the aim of developing a general and straightforward procedure for the intracellular delivery of naked peptide nucleic acids (PNAs), we designed an intracellularly biodegradable triphenylphosphonium (TPP) cation based transporter system. In this system, TPP is linked, via a biolabile disulfide bridge, to an activated mercaptoethoxycarbonyl moiety, allowing its direct coupling to the N-terminal extremity of a free PNA through a carbamate bond. We found that such TPP-PNA-carbamate conjugates were highly stable in a cell culture medium containing fetal calf serum. In a glutathione-containing medium mimicking the cytosol, the conjugates were rapidly degraded into an unstable intermediate, which spontaneously decomposed, releasing the free PNA. Using a fluorescence-labeled PNA–TPP conjugate, we demonstrated that conjugates were taken up by cells. Efficient cellular uptake and release of the PNA into the cytosol was further confirmed by the anti-HIV activity measured for the TPP-conjugate of a 16-mer PNA targeting the TAR region of the HIV-1 genome. This conjugate exhibited an IC50 value of 1 μM, while the free 16-mer PNA did not inhibit replication of HIV in the same cellular test. PMID:18707540

  3. Arsenate uptake and arsenite simultaneous sorption and oxidation by Fe-Mn binary oxides: influence of Mn/Fe ratio, pH, Ca2+, and humic acid.

    PubMed

    Zhang, Gaosheng; Liu, Huijuan; Qu, Jiuhui; Jefferson, William

    2012-01-15

    Arsenate retention, arsenite sorption and oxidation on the surfaces of Fe-Mn binary oxides may play an important role in the mobilization and transformation of arsenic, due to the common occurrence of these oxides in the environment. However, no sufficient information on the sorption behaviors of arsenic on Fe-Mn binary oxides is available. This study investigated the influences of Mn/Fe molar ratio, solution pH, coexisting calcium ions, and humic acids have on arsenic sorption by Fe-Mn binary oxides. To create Fe-Mn binary oxides, simultaneous oxidation and co-precipitation methods were employed. The Fe-Mn binary oxides exhibited a porous crystalline structure similar to 2-line ferrihydrite at Mn/Fe ratios 1:3 and below, whereas exhibited similar structures to δ-MnO(2) at higher ratios. The As(V) sorption maximum was observed at a Mn/Fe ratio of 1:6, but As(III) uptake maximum was at Mn/Fe ratio 1:3. However, As(III) adsorption capacity was much higher than that of As(V) at each Mn/Fe ratio. As(V) sorption was found to decrease with increasing pH, while As(III) sorption edge was different, depending on the content of MnO(2) in the binary oxides. The presence of Ca(2+) enhanced the As(V) uptake under alkaline pH, but did not significantly influence the As(III) sorption by 1:9 Fe-Mn binary oxide; whereas the presence of humic acid slightly reduced both As(V) and As(III) uptake. These results indicate that As(III) is more easily immobilized than As(V) in the environment, where Fe-Mn binary oxides are available as sorbents and they represent attractive adsorbents for both As(V) and As(III) removal from water and groundwater.

  4. Synthesis and characterization of poly(maleic acid)-grafted crosslinked chitosan nanomaterial with high uptake and selectivity for Hg(II) sorption.

    PubMed

    Ge, Huacai; Hua, Tingting

    2016-11-20

    Chitosan-poly(maleic acid) nanomaterial (PMACS) with the size of 400-900nm was synthesized by grafting poly(maleic acid) onto chitosan and then crosslinking with glutaraldehyde. The synthesis conditions were optimized. The structure and morphology of PMACS were characterized by FT-IR, XRD, SEM and TGA. PMACS was used to adsorb some heavy metal ions such as Hg(II), Pb(II), Cu(II), Cd(II), Co(II), and Zn(II). The results indicated that PMACS had selectivity for Hg(II) sorption. The effects of various variables for sorption of Hg(II) were further explored. The maximum capacity for Hg(II) sorption was found to be 1044mgg(-1) at pH 6.0, which could compare with the maximal value of the recently reported other sorbents. The sorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The rising of temperature benefited the uptake and the sorption was a spontaneous chemical process. The sorbent could be reused with EDTA. Hence, the nanomaterial would be used as a selective and high uptake sorbent in the removal of Hg(II) from effluents.

  5. Synthesis and characterization of poly(maleic acid)-grafted crosslinked chitosan nanomaterial with high uptake and selectivity for Hg(II) sorption.

    PubMed

    Ge, Huacai; Hua, Tingting

    2016-11-20

    Chitosan-poly(maleic acid) nanomaterial (PMACS) with the size of 400-900nm was synthesized by grafting poly(maleic acid) onto chitosan and then crosslinking with glutaraldehyde. The synthesis conditions were optimized. The structure and morphology of PMACS were characterized by FT-IR, XRD, SEM and TGA. PMACS was used to adsorb some heavy metal ions such as Hg(II), Pb(II), Cu(II), Cd(II), Co(II), and Zn(II). The results indicated that PMACS had selectivity for Hg(II) sorption. The effects of various variables for sorption of Hg(II) were further explored. The maximum capacity for Hg(II) sorption was found to be 1044mgg(-1) at pH 6.0, which could compare with the maximal value of the recently reported other sorbents. The sorption followed the pseudo-second-order kinetics and Langmuir isotherm models. The rising of temperature benefited the uptake and the sorption was a spontaneous chemical process. The sorbent could be reused with EDTA. Hence, the nanomaterial would be used as a selective and high uptake sorbent in the removal of Hg(II) from effluents. PMID:27561493

  6. Elevated dairy fat intake in lactating women alters milk lipid and fatty acids without detectible changes in expression of genes related to lipid uptake or synthesis.

    PubMed

    Yahvah, Katherine M; Brooker, Sarah L; Williams, Janet E; Settles, Matthew; McGuire, Mark A; McGuire, Michelle K

    2015-03-01

    Previous work has demonstrated that elevated maternal lipid intake (particularly from dairy products) is associated with increased lipids and altered fatty acid profile in milk produced by healthy lactating women. To investigate our primary hypothesis that a maternal diet rich in full-fat dairy products would simultaneously increase milk lipid percent and expression of genes related to the uptake and/or de novo biosynthesis of milk lipids, we provided 15 lactating women with diets enriched in full-fat or nonfat dairy products for 14 days each in a randomized, crossover study with a 2-week washout period. Milk fat (%) was lower when women consumed the low-fat compared with the full-fat dairy diet (2.41% ± 0.31% vs 3.35% ± 0.28%, respectively; P < .05); concentrations of more than 20 fatty acids also differed. However, neither conservatively evaluated microarray data nor quantitative real-time polymerase chain reaction analysis uncovered any treatment effects on expression of genes related to lipid synthesis or uptake. These data suggest that alteration in gene expression in the lactating human mammary gland is likely not the primary mechanism by which consumption of a high-fat diet affects milk fat percent in healthy, lactating women.

  7. Comparison of the uptake of methacrylate-based nanoparticles in static and dynamic in vitro systems as well as in vivo.

    PubMed

    Rinkenauer, Alexandra C; Press, Adrian T; Raasch, Martin; Pietsch, Christian; Schweizer, Simon; Schwörer, Simon; Rudolph, Karl L; Mosig, Alexander; Bauer, Michael; Traeger, Anja; Schubert, Ulrich S

    2015-10-28

    Polymer-based nanoparticles are promising drug delivery systems allowing the development of new drug and treatment strategies with reduced side effects. However, it remains a challenge to screen for new and effective nanoparticle-based systems in vitro. Important factors influencing the behavior of nanoparticles in vivo cannot be simulated in screening assays in vitro, which still represent the main tools in academic research and pharmaceutical industry. These systems have serious drawbacks in the development of nanoparticle-based drug delivery systems, since they do not consider the highly complex processes influencing nanoparticle clearance, distribution, and uptake in vivo. In particular, the transfer of in vitro nanoparticle performance to in vivo models often fails, demonstrating the urgent need for novel in vitro tools that can imitate aspects of the in vivo situation more accurate. Dynamic cell culture, where cells are cultured and incubated in the presence of shear stress has the potential to bridge this gap by mimicking key-features of organs and vessels. Our approach implements and compares a chip-based dynamic cell culture model to the common static cell culture and mouse model to assess its capability to predict the in vivo success more accurately, by using a well-defined poly((methyl methacrylate)-co-(methacrylic acid)) and poly((methyl methacrylate)-co-(2-dimethylamino ethylmethacrylate)) based nanoparticle library. After characterization in static and dynamic in vitro cell culture we were able to show that physiological conditions such as cell-cell communication of co-cultured endothelial cells and macrophages as well as mechanotransductive signaling through shear stress significantly alter cellular nanoparticle uptake. In addition, it could be demonstrated by using dynamic cell cultures that the in vivo situation is simulated more accurately and thereby can be applied as a novel system to investigate the performance of nanoparticle systems in vivo

  8. UPTAKE OF HEAVY METALS IN BATCH SYSTEMS BY A RECYCLED IRON-BEARING MATERIAL

    EPA Science Inventory

    An iron-bearing material deriving from surface finishing operations in the manufacturing of cast-iron components demonstrates potential for removal of heavy metals from aqueous waste streams. Batch isotherm and rate experiments were conducted for uptake of cadmium, zinc, and lead...

  9. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Uric acid test system. 862.1775 Section 862.1775...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to...

  10. 21 CFR 862.1775 - Uric acid test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Uric acid test system. 862.1775 Section 862.1775...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1775 Uric acid test system. (a) Identification. A uric acid test system is a device intended to...

  11. Factors Associated with Uptake of Visual Inspection with Acetic Acid (VIA) for Cervical Cancer Screening in Western Kenya

    PubMed Central

    Orang’o, Elkanah Omenge; Wachira, Juddy; Asirwa, Fredrick Chite; Busakhala, Naftali; Naanyu, Violet; Kisuya, Job; Otieno, Grieven; Keter, Alfred; Mwangi, Ann; Inui, Thomas

    2016-01-01

    Purpose Cervical cancer screening has been successful in reducing the rates of cervical cancer in developed countries, but this disease remains the leading cause of cancer deaths among women in sub-Saharan Africa. We sought to understand factors associated with limited uptake of screening services in our cervical cancer-screening program in Western Kenya. Participants and Methods Using items from a previously validated cancer awareness questionnaire repurposed for use in cervical cancer and culturally adapted for use in Kenya, we interviewed 2,505 women aged 18–55 years receiving care in gynecology clinics or seeking other services in 4 health facilities in Western Kenya between April 2014 and September 2014. We used logistic regression modeling to assess factors associated with uptake (or non-uptake), associated odds ratios (ORs) and the 95% confidence intervals (95% CI). Results Only two hundred and seventy-three women out of 2505 (11%) accepted VIA cervical cancer screening. Knowledge of just how women are screened for cervical cancer was significantly associated with reduced uptake of cervical cancer screening (OR: 0.53; CI 0.38–0.73) as was fear that screening would reveal a cancer (OR 0.70; CI 0.63–0.77), and reliance on prayer with the onset of illness (OR 0.43; CI 0.26–0.71). Participants who thought that one should get cervical cancer screening even if there were no symptoms were more than twice as likely to accept cervical cancer screening (OR 2.21; 95% CI 1.24–3.93). Older patients, patients living with HIV and women who do not know if bleeding immediately after sex might be a sign of cervical cancer were also more likely to accept screening (OR 1.03, CI 1.02–1.04; OR 1.78, CI 1.01–3.14; OR 2.39, CI 1.31–4.39, respectively). Conclusions In our population, a high percent of women knew that it is appropriate for all women to get cervical cancer screening, but only a small proportion of women actually got screening. There may be an

  12. Uptake measurements of ethanol on ice surfaces and on supercooled aqueous solutions doped with nitric acid between 213 and 243 K.

    PubMed

    Kerbrat, M; Le Calvé, S; Mirabel, Ph

    2007-02-01

    Uptake of ethanol either on pure frozen ice surfaces or supercooled solutions doped with HNO3 (0.63 and 2.49 wt %) has been investigated using a coated wall flow tube coupled to a mass spectrometric detection. The experiments were conducted over the temperature range of 213-243 K. Uptake of ethanol on these surfaces was always found to be totally reversible whatever were the experimental conditions. The number of ethanol molecules adsorbed per surface unit was conventionally plotted as a function of ethanol concentration in the gas phase and subsequently analyzed using Langmuir's model. The amount of ethanol molecules taken up on nitric acid doped-ice surfaces was found to increase largely with increasing nitric acid concentrations. For example at 223 K, and for an ethanol gas-phase concentration of 1x10(13) molecules cm3, the number of adsorbed molecules are (in units of molecules cm-2): approximately 1.3x10(14) on pure ice; approximately 1.4x10(15) on ice doped with HNO3 0.63 wt %; approximately 7.5x10(15) on ice doped with HNO3, 2.49 wt %, i.e. 60 times larger than on pure ice. Since, according to the shape of the isotherms, the adsorption did not proceed beyond monolayer coverage, the enormous increase of ethanol uptake was explained by considering its dissolution in either a supercooled liquid layer (T<230 K) or a liquid solution (T>230 K). The formation of both was indeed favored by the presence of the HNO3. Our experimental results suggest that the amount of ethanol dissolved in such supercooled solutions follows Henry's law and that the Henry's law constants at low temperatures, i.e., 223-243 K, can be estimated by extrapolation from higher temperatures. Such supercooled solutions which exist in the troposphere either in deep convective clouds or in mixed clouds for temperature above 233 K, might be responsible for the scavenging of large amounts of soluble species, such as nitric and sulfuric acids, oxygenated VOCs including alcohols, carboxylic acids, and

  13. Nucleic acid detection systems for enteroviruses.

    PubMed Central

    Rotbart, H A

    1991-01-01

    The enteroviruses comprise nearly 70 human pathogens responsible for a wide array of diseases including poliomyelitis, meningitis, myocarditis, and neonatal sepsis. Current diagnostic tests for the enteroviruses are limited in their use by the slow growth, or failure to grow, of certain serotypes in culture, the antigenic diversity among the serotypes, and the low titer of virus in certain clinical specimens. Within the past 6 years, applications of molecular cloning techniques, in vitro transcription vectors, automated nucleic acid synthesis, and the polymerase chain reaction have resulted in significant progress toward nucleic acid-based detection systems for the enteroviruses that take advantage of conserved genomic sequences across many, if not all, serotypes. Similar approaches to the study of enteroviral pathogenesis have already produced dramatic advances in our understanding of how these important viruses cause their diverse clinical spectra. PMID:1649002

  14. Removal of copper from acid wastewater of bioleaching by adsorption onto ramie residue and uptake by Trichoderma viride.

    PubMed

    Wang, Buyun; Wang, Kai

    2013-05-01

    A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue. PMID:23567687

  15. Using a Genome-Scale Metabolic Model of Enterococcus faecalis V583 To Assess Amino Acid Uptake and Its Impact on Central Metabolism

    PubMed Central

    Solheim, Margrete; van Grinsven, Koen W. A.; Olivier, Brett G.; Levering, Jennifer; Grosseholz, Ruth; Hugenholtz, Jeroen; Holo, Helge; Nes, Ingolf; Teusink, Bas; Kummer, Ursula

    2014-01-01

    Increasing antibiotic resistance in pathogenic bacteria necessitates the development of new medication strategies. Interfering with the metabolic network of the pathogen can provide novel drug targets but simultaneously requires a deeper and more detailed organism-specific understanding of the metabolism, which is often surprisingly sparse. In light of this, we reconstructed a genome-scale metabolic model of the pathogen Enterococcus faecalis V583. The manually curated metabolic network comprises 642 metabolites and 706 reactions. We experimentally determined metabolic profiles of E. faecalis grown in chemically defined medium in an anaerobic chemostat setup at different dilution rates and calculated the net uptake and product fluxes to constrain the model. We computed growth-associated energy and maintenance parameters and studied flux distributions through the metabolic network. Amino acid auxotrophies were identified experimentally for model validation and revealed seven essential amino acids. In addition, the important metabolic hub of glutamine/glutamate was altered by constructing a glutamine synthetase knockout mutant. The metabolic profile showed a slight shift in the fermentation pattern toward ethanol production and increased uptake rates of multiple amino acids, especially l-glutamine and l-glutamate. The model was used to understand the altered flux distributions in the mutant and provided an explanation for the experimentally observed redirection of the metabolic flux. We further highlighted the importance of gene-regulatory effects on the redirection of the metabolic fluxes upon perturbation. The genome-scale metabolic model presented here includes gene-protein-reaction associations, allowing a further use for biotechnological applications, for studying essential genes, proteins, or reactions, and the search for novel drug targets. PMID:25527553

  16. The Uptake of GABA in Trypanosoma cruzi.

    PubMed

    Galvez Rojas, Robert L; Ahn, Il-Young; Suárez Mantilla, Brian; Sant'Anna, Celso; Pral, Elizabeth Mieko Furusho; Silber, Ariel Mariano

    2015-01-01

    Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway.

  17. The Uptake of GABA in Trypanosoma cruzi.

    PubMed

    Galvez Rojas, Robert L; Ahn, Il-Young; Suárez Mantilla, Brian; Sant'Anna, Celso; Pral, Elizabeth Mieko Furusho; Silber, Ariel Mariano

    2015-01-01

    Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway. PMID:25851259

  18. Diatoms Si uptake capacity drives carbon export in coastal upwelling systems

    NASA Astrophysics Data System (ADS)

    Abrantes, Fatima; Cermeno, Pedro; Lopes, Cristina; Romero, Oscar; Matos, Lélia; Van Iperen, Jolanda; Rufino, Marta; Magalhães, Vitor

    2016-07-01

    Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica-precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia-Canary, Benguela, Peru-Humboldt, California, and Somalia-Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in conjunction with environmental variables of coastal upwelling systems such as upwelling strength, satellite-derived net primary production, and surface water nutrient concentrations shows different relations between SDA and primary production on the regional scale. On the global scale, SDA appears modulated by the capacity of diatoms to take up silicic acid, which ultimately sets an upper limit to global export production in these ocean regions.

  19. Phytic acid interactions in food systems.

    PubMed

    Cheryan, M

    1980-01-01

    Phytic acid is present in many plant systems, constituting about 1 to 5% by weight of many cereals and legumes. Concern about its presence in food arises from evidence that it decreases the bioavailability of many essential minerals by interacting with multivalent cations and/or proteins to form complexes that may be insoluble or otherwise unavailable under physiologic conditions. The precise structure of phytic acid and its salts is still a matter of controversy and lack of a good method of analysis is also a problem. It forms fairly stable chelates with almost all multivalent cations which are insoluble about pH 6 to 7, although pH, type, and concentration of cation have a tremendous influence on their solubility characteristics. In addition, at low pH and low cation concentration, phytate-protein complexes are formed due to direct electrostatic interaction, while at pH > 6 to 7, a ternary phytic acid-mineral-protein complex is formed which dissociates at high Na+ concentrations. These complexes appear to be responsible for the decreased bioavailability of the complexed minerals and are also more resistant to proteolytic digestion at low pH. Development of methods for producing low-phytate food products must take into account the nature and extent of the interactions between phytic acid and other food components. Simple mechanical treatment, such as milling, is useful for those seeds in which phytic acid tends to be localized in specific regions. Enzyme treatment, either directly with phytase or indirectly through the action of microorganisms, such as yeast during breadmaking, is quite effective, provided pH and other environmental conditions are favorable. It is also possible to produce low-phytate products by taking advantage of some specific interactions. For example, adjustment of pH and/or ionic strength so as to dissociate phytate-protein complexes and then using centrifugation or ultrafiltration (UF) has been shown to be useful. Phytic acid can also

  20. Inhibitory effect on the uptake and diffusion of Cd(2+) onto soybean hull sorbent in Cd-Pb binary sorption systems.

    PubMed

    Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Colombo, Andréia; Geraldi, Claudinéia L; Trigueros, Daniela E G

    2015-05-01

    The uptake of Cd(2+) and Pb(2+) ions by a soybean hull (SH) biosorbent in single and binary systems has been investigated. Sorption tests regarding SH in natura and chemically treated were carried out testing a suitable value range of solution pH, sorption temperature and shaking velocity. Sorption capacity is improved at pH 4, 30 °C temperature and 100 rpm. When a strong base is applied, a related-to-untreated SH increasing of 20% in the sorption capacity of Pb(2+) ions was observed, but with poor results for Cd(2+) uptake. Additionally, a relatively strong decreasing in both sorption capacities of Pb(2+) and Cd(2+) ions was evidenced for all acidic treatments. Regarding untreated SH, kinetic sorption data of both metals were well-interpreted by a pseudo second-order model and a rate-limiting step on the basis of an intra-particle diffusion model was suggested to occur. An inhibitory effect of Pb(2+) diffusion over Cd(2+) one was observed, limiting to reach the obtained maximum sorption capacity in single system. Maximum adsorption capacities of 0.49 and 0.67mequivg(-1) for Cd(2+) and Pb(2+), respectively, were predicted by the Langmuir isotherm model that reproduced well the equilibrium sorption data for single systems. The inhibitory effect of one metal over the other one was verified in equilibrium sorption data for binary systems interpreted on the basis of a modified extended Langmuir isotherm model, predicting changes in metal affinity onto the SH surface. Finally, SH is an alternative biosorbent with a great potential for the wastewater treatment containing cadmium and lead ions.

  1. Acid preservation systems for food products

    SciTech Connect

    Tiberio, J. E.; Cirigiano, M. C.

    1984-10-16

    Fumaric acid is used in combination with critical amounts of acetic acid to preserve acid containing food products from microbiological spoilage in the absence of or at reduced levels of chemical preservative.

  2. Effects of inorganic and organic amendments on the uptake of lead and trace elements by Brassica chinensis grown in an acidic red soil.

    PubMed

    Tang, Xianjin; Li, Xia; Liu, Xingmei; Hashmi, Muhammad Z; Xu, Jianming; Brookes, Philip C

    2015-01-01

    A greenhouse study was conducted to investigate the effects of inorganic (phosphate rock, single superphosphate and calcium magnesium phosphate) and organic amendments (peat, straw manure and pig manure) on the uptake of lead (Pb) and trace elements by Chinese Cabbage (Brassica chinensis) grown in an acidic red soil. The application of all organic amendments increased the soil pH while inorganic amendments such as single superphosphate did not. Both inorganic and organic amendments decreased the availability and uptake of Pb while the organic amendments were superior to the inorganic (phosphate) amendments in reducing the availability of the more labile (soluble and exchangeable Pb) forms of soil Pb. More Pb was taken up by roots than shoots with all soil amendments. Among the organic amendments, straw manure and pig manure caused the largest decrease in Pb availability at 456.5 and 457.3 mg kg(-1), respectively, when a high level of 30 g organic amendments kg(-1) was applied. The organic amendments greatly increased the fraction D targeted to Fe-Mn oxides bound Pb, and decreased the fraction A (water-soluble), B (exchangeable), and C (carbonate-bound), thereby decreasing the solubility and mobility of Pb in soil. The organic amendments also significantly improved the concentrations of Fe, Mn, Cu and Zn in the soil and shoots (except Fe in shoots and/or roots), which are essential for plant nutrition. The organic amendments of straw and pig manure lowered the availability and uptake of Pb but not that of other trace metals. Thus, these amendments have the potential to remediate Pb-contaminated soils in situ. PMID:24992219

  3. Muscle-specific glucose and free fatty acid uptake after sprint interval and moderate-intensity training in healthy middle-aged men.

    PubMed

    Eskelinen, Jari-Joonas; Heinonen, Ilkka; Löyttyniemi, Eliisa; Saunavaara, Virva; Kirjavainen, Anna; Virtanen, Kirsi A; Hannukainen, Jarna C; Kalliokoski, Kari K

    2015-05-01

    We tested the hypothesis that sprint interval training (SIT) causes larger improvements in glucose and free fatty acid uptake (FFAU) in lower and upper body muscles than moderate-intensity training (MIT). Twenty-eight healthy, untrained, middle-aged men were randomized into SIT (n = 14, 4-6 × 30 s of all-out cycling/4 min recovery) and MIT groups [n = 14, 40-60 min cycling at 60% of peak O2 uptake (V̇o2 peak)] and completed six training sessions within 2 wk. Pre- and postmeasurements included V̇o2 peak, whole body (M-value), muscle-specific insulin-stimulated glucose uptake (GU), and fasting FFAU measured with positron emission tomography in thigh [quadriceps femoris (QF) and hamstrings] and upper body (deltoids, biceps, and triceps brachii) muscles. V̇o2 peak and M-value improved significantly by 6 and 12% in SIT, and 3 and 8% in MIT, respectively,. GU increased significantly only in the QF, and there was no statistically significant difference between the training modes. GU increased in all four heads of QF in response to SIT, but only in the vasti muscles in response to MIT, whereas in rectus femoris the response was completely lacking. Training response in FFAU in QF was smaller and nonsignificant, but it also differed between the training modes in the rectus femoris. In conclusion, SIT and MIT increased insulin-stimulated GU only in the main working muscle QF and not in the upper body muscles. In addition, the biarticular rectus femoris did not respond to moderate-intensity training, reflecting most probably poor activation of it during moderate-intensity cycling. PMID:25767035

  4. Simultaneous monitoring of electrical capacitance and water uptake activity of plant root system

    NASA Astrophysics Data System (ADS)

    Cseresnyés, Imre; Takács, Tünde; Füzy, Anna; Rajkai, Kálmán

    2014-10-01

    Pot experiments were designed to test the applicability of root electrical capacitance measurement for in situ monitoring of root water uptake activity by growing cucumber and bean cultivars in a growth chamber. Half of the plants were inoculated with Funneliformis mosseae arbuscular mycorrhizal fungi, while the other half served as non-infected controls. Root electrical capacitance and daily transpiration were monitored during the whole plant ontogeny. Phenology-dependent changes of daily transpiration (related to root water uptake) and root electrical capacitance proved to be similar as they showed upward trends from seedling emergence to the beginning of flowering stage, and thereafter decreased continuously during fruit setting. A few days after arbuscular mycorrhizal fungi-colonization, daily transpiration and root electrical capacitance of infected plants became significantly higher than those of non-infected counterparts, and the relative increment of the measured parameters was greater for the more highly mycorrhizal-dependent bean cultivar compared to that of cucumber. Arbuscular mycorrhizal fungi colonization caused 29 and 69% relative increment in shoot dry mass for cucumbers and beans, respectively. Mycorrhization resulted in 37% increase in root dry mass for beans, but no significant difference was observed for cucumbers. Results indicate the potential of root electrical capacitance measurements for monitoring the changes and differences of root water uptake rate.

  5. Fluorous Peptide Nucleic Acids: PNA Analogues with Fluorine in Backbone (γ-CF2-apg-PNA) Enhance Cellular Uptake.

    PubMed

    Ellipilli, Satheesh; Ganesh, Krishna N

    2015-09-18

    Fluorous PNA analogues possessing fluorine as inherent part of aminopropylglycine (apg) backbone (γ-CF2-apg PNA) have been synthesized and evaluated for biophysical and cell penetrating properties. These form duplexes of higher thermal stability with cRNA than cDNA, although destabilized compared to duplexes of standard aeg-PNA. Cellular uptake of the fluorinated γ-CF2-apg PNAs in NIH 3T3 and HeLa cells was 2-3-fold higher compared to that of nonfluorinated apg PNA, with NIH 3T3 cells showing better permeability compared to HeLa cells. The backbone fluorinated PNAs, which are first in this class, when combined with other chemical modifications may have potential for future PNA-based antisense agents.

  6. Epidermal growth factor inhibits radioiodine uptake but stimulates deoxyribonucleic acid synthesis in newborn rat thyroids grown in nude mice

    SciTech Connect

    Ozawa, S.; Spaulding, S.W. )

    1990-08-01

    We have studied the effect of altering the level of circulating epidermal growth factor (EGF) on the function and growth of newborn rat thyroids transplanted into nude mice. Preliminary studies confirmed that sialoadenectomy reduced circulating EGF levels in nude mice (from 0.17 +/- 0.02 to 0.09 +/- 0.02 ng/ml), and that ip injection of 5 micrograms EGF raised EGF levels (the peak level of 91.7 +/- 3.3 ng/ml was achieved at 30 min, with a subsequent half-life of about 1 h). The radioiodine uptake by newborn rat thyroid transplants in the sialoadenectomized and sham-operated animals correlated inversely with the circulating EGF levels determined when the mice were killed (r = -0.99). Low-dose TSH treatment (0.1 microU/day) generally stimulated the radioiodine uptake, but high-dose TSH groups (100 microU/day) were not significantly different from the control group. The 5-day nuclear (3H)thymidine labeling index was 6.8 +/- 0.5% IN newborn rat thyroid transplants grown in sialoadenectomized animals, 13.1 +/- 0.3% in sham-operated animals, and 16.8 +/- 0.5% in nude mice receiving 5 micrograms EGF ip daily. In general, both low-dose and high-dose TSH promoted DNA synthesis under low EGF conditions but were ineffective in the presence of higher levels of EGF. Adult rat thyroid transplants showed no significant responses. Although sialoadenectomy may alter other factors besides EGF, it appears that changes in the levels of circulating EGF within the physiological range affect the function and growth of newborn rat thyroid transplants. Circulating EGF may play a role in thyroid maturation and may also be involved in the regulation of thyroid function throughout life.

  7. Citric acid modifies surface properties of commercial CeO2 nanoparticles reducing their toxicity and cerium uptake in radish (Raphanus sativus) seedlings.

    PubMed

    Trujillo-Reyes, J; Vilchis-Nestor, A R; Majumdar, S; Peralta-Videa, J R; Gardea-Torresdey, J L

    2013-12-15

    Little is known about the mobility, reactivity, and toxicity to plants of coated engineered nanoparticles (ENPs). Surface modification may change the interaction of ENPs with living organisms. This report describes surface changes in commercial CeO2 NPs coated with citric acid (CA) at molar ratios of 1:2, 1:3, 1:7, and 1:10 CeO2:CA, and their effects on radish (Raphanus sativus) seed germination, cerium and nutrients uptake. All CeO2 NPs and their absorption by radish plants were characterized by TEM, DLS, and ICP-OES. Radish seeds were germinated in pristine and CA coated CeO2 NPs suspensions at 50mg/L, 100mg/L, and 200mg/L. Deionized water and CA at 100mg/L were used as controls. Results showed ζ potential values of 21.6 mV and -56 mV for the pristine and CA coated CeO2 NPs, respectively. TEM images showed denser layers surrounding the CeO2 NPs at higher CA concentrations, as well as better distribution and smaller particle sizes. None of the treatments affected seed germination. However, at 200mg/L the CA coated NPs at 1:7 ratio produced significantly (p ≤ 0.05) more root biomass, increased water content and reduced by 94% the Ce uptake, compared to bare NPs. This suggests that CA coating decrease CeO2 NPs toxicity to plants.

  8. Enhancing degradation of total petroleum hydrocarbons and uptake of heavy metals in a wetland microcosm planted with Phragmites communis by humic acids addition.

    PubMed

    Sung, Kijune; Kim, Ki Seob; Park, Soyoung

    2013-01-01

    The effects of humic acid (HA) on heavy-metal uptake by plants and degradation of total petroleum hydrocarbons (TPHs) in a wetland microcosm planted with Phragmites communis were evaluated by comparing waterlogged soils and water-drained upland soils. Experiments were conducted on soils artificially contaminated with heavy metals (Pb, Cu, Cd, Ni) and diesel fuel. HA showed a positive influence on biomass increase for all conditions, but more for belowground than aboveground biomass, and lower in contaminated than uncontaminated soil. The bioavailability and leachability factor (BLF) for all heavy metals except Ni increased with HA addition in both the control and the P. communis planted microcosms, suggesting that more heavy metals could be potentially phytoavailable for plant uptake. Microbial activities were not affected by both heavy metals and TPH contamination, and HA effects on stimulating microbial activities were much greater in the contaminated soil than under uncontaminated conditions. HA addition enhanced the degradation of TPH and n-alkane in waterlogged conditions. The results show that HA can increase the remedial performance in P. communis dominated wetlands simultaneously contaminated with heavy metals and petroleum hydrocarbons and thus prevent contamination of groundwater or other adjacent ecosystems.

  9. Morphine Induces Redox-Based Changes in Global DNA Methylation and Retrotransposon Transcription by Inhibition of Excitatory Amino Acid Transporter Type 3–Mediated Cysteine Uptake

    PubMed Central

    Trivedi, Malav; Shah, Jayni; Hodgson, Nathaniel; Byun, Hyang-Min

    2014-01-01

    Canonically, opioids influence cells by binding to a G protein–coupled opioid receptor, initiating intracellular signaling cascades, such as protein kinase, phosphatidylinositol 3-kinase, and extracellular receptor kinase pathways. This results in several downstream effects, including decreased levels of the reduced form of glutathione (GSH) and elevated oxidative stress, as well as epigenetic changes, especially in retrotransposons and heterochromatin, although the mechanism and consequences of these actions are unclear. We characterized the acute and long-term influence of morphine on redox and methylation status (including DNA methylation levels) in cultured neuronal SH-SY5Y cells. Acting via μ-opioid receptors, morphine inhibits excitatory amino acid transporter type 3–mediated cysteine uptake via multiple signaling pathways, involving different G proteins and protein kinases in a temporal manner. Decreased cysteine uptake was associated with decreases in both the redox and methylation status of neuronal cells, as defined by the ratios of GSH to oxidized forms of glutathione and S-adenosylmethionine to S-adenosylhomocysteine levels, respectively. Further, morphine induced global DNA methylation changes, including CpG sites in long interspersed nuclear elements (LINE-1) retrotransposons, resulting in increased LINE-1 mRNA. Together, these findings illuminate the mechanism by which morphine, and potentially other opioids, can influence neuronal-cell redox and methylation status including DNA methylation. Since epigenetic changes are implicated in drug addiction and tolerance phenomenon, this study could potentially extrapolate to elucidate a novel mechanism of action for other drugs of abuse. PMID:24569088

  10. Uptake Mechanism for Iodine Species to Black Carbon

    SciTech Connect

    Choung, Sungwook; Um, Wooyong; Kim, Min Kyung; Kim, Min-Gyu

    2013-08-13

    Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I-) and iodate (IO3-) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH~3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray Absorption Fine Structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound to carbon atom in polycyclic aromatic hydrocarbons present in the BC. The computed distribution coefficients (i.e., Kd values) suggest that the BC materials retard significantly the transport of iodide at low pH in environmental systems containing even a small amount of BC.

  11. Uptake mechanism for iodine species to black carbon.

    PubMed

    Choung, Sungwook; Um, Wooyong; Kim, Minkyung; Kim, Min-Gyu

    2013-09-17

    Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I(-)) and iodate (IO3(-)) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH of ~3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray absorption fine structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound to carbon atom in polycyclic aromatic hydrocarbons present in the BC. The computed distribution coefficients (i.e., Kd values) suggest that the BC materials retard significantly the transport of iodide at low pH in environmental systems containing even a small amount of BC.

  12. Effective uptake of decontaminating agent (citric acid) from aqueous solution by mesoporous and microporous materials: an adsorption process.

    PubMed

    Gokulakrishnan, Narasimhan; Pandurangan, Arumugam; Sinha, Pradeep Kumar

    2006-04-01

    The presence of citric acid in decontamination waste can cause complexation of the radioactive cations resulting in interferences in their removal by various treatment processes such as chemical precipitation, ion-exchange, etc., which are employed for the removal of radioactivity and may cause potential danger to the environment. Mesoporous Al-MCM-41 (Si/Al=30, 51, 72 and 97) and Si-MCM-41 molecular sieves were synthesized hydrothermally and characterized by XRD, BET (surface area) and FT-IR to evaluate the removal of citric acid through an adsorption process. Adsorption of citric acid over Al-MCM-41 shows the applicability of Freundlich and Langmuir isotherm and follows first order kinetics. The effects of contact time, concentration of citric acid, adsorbents (various Si/Al ratios of Al-MCM-41, Si-MCM-41, Hbeta zeolite and commercial carbon) and pH have been investigated. It has been found that the amount of citric acid adsorbed per unit gram of catalyst followed the order Al-MCM-41 (Si/Al=30)>Al-MCM-41 (Si/Al=51)>activated charcoal>Al-MCM-41 (Si/Al=72)>Al-MCM-41 (Si/Al=97)>Si-MCM-41>Hbeta zeolite.

  13. Dopamine uptake and cocaine binding mechanisms: the involvement of charged amino acids from the transmembrane domains of the human dopamine transporter.

    PubMed

    Dar, Dalit E; Metzger, Thomas G; Vandenbergh, David J; Uhl, George R

    2006-05-24

    The wild type human dopamine transporter (DAT) and five DAT mutants were transfected into COS-7 cells and their ability to uptake dopamine or to bind cocaine was examine three days later. In each mutant, a single charged amino acid, located in areas that initial hydrophobic analysis had indicated were DAT transmembrane domains was substituted by alanine. Mutants used in this study were lysines 257 and 525 (termed K257A and K525A), arginines 283 and 521 (termed R283A and R521A), and glutamate 491 (termed E491A). Dopamine affinity was significantly enhanced in the K257A and R283A mutants, and the IC(50) for displacement of the radioactive cocaine analog 2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (CFT) by cocaine was significantly elevated in the E491A mutant. All mutants displayed a reduction or complete loss of the maximal velocity (V(m)) of dopamine transport. PMID:16674939

  14. System A amino acid transporter SNAT2 shows subtype-specific affinity for betaine and hyperosmotic inducibility in placental trophoblasts.

    PubMed

    Nishimura, Tomohiro; Yagi, Risa; Usuda, Mariko; Oda, Kenji; Yamazaki, Mai; Suda, Sayaka; Takahashi, Yu; Okazaki, Fumiyasu; Sai, Yoshimichi; Higuchi, Kei; Maruyama, Tetsuo; Tomi, Masatoshi; Nakashima, Emi

    2014-05-01

    Betaine uptake is induced by hypertonic stress in a placental trophoblast cell line, and involvement of amino acid transport system A was proposed. Here, we aimed to identify the subtype(s) of system A that mediates hypertonicity-induced betaine uptake. Measurement of [(14)C]betaine uptake by HEK293 cells transiently transfected with human or rat sodium-coupled neutral amino acid transporters (SNATs), SNAT1, SNAT2 and SNAT4 revealed that only human and rat SNAT2 have betaine uptake activity. The Michaelis constants (Km) of betaine uptake by human and rat SNAT2 were estimated to be 5.3 mM and 4.6 mM, respectively. Betaine exclusively inhibited the uptake activity of SNAT2 among the rat system A subtypes. We found that rat SNAT1, SNAT2 and SNAT4 were expressed at the mRNA level under isotonic conditions, while expression of SNAT2 and SNAT4 was induced by hypertonicity in TR-TBT 18d-1 cells. Western blot analyses revealed that SNAT2 expression on plasma membrane of TR-TBT 18d-1 cells was more potently induced by hypertonicity than that in total cell lysate. Immunocytochemistry confirmed the induction of SNAT2 expression in TR-TBT 18d-1 cells exposed to hypertonic conditions and indicated that SNAT2 was localized on the plasma membrane in these cells. Our results indicate that SNAT2 transports betaine, and that tonicity-sensitive SNAT2 expression may be involved in regulation of betaine concentration in placental trophoblasts. PMID:24434061

  15. System A amino acid transporter SNAT2 shows subtype-specific affinity for betaine and hyperosmotic inducibility in placental trophoblasts.

    PubMed

    Nishimura, Tomohiro; Yagi, Risa; Usuda, Mariko; Oda, Kenji; Yamazaki, Mai; Suda, Sayaka; Takahashi, Yu; Okazaki, Fumiyasu; Sai, Yoshimichi; Higuchi, Kei; Maruyama, Tetsuo; Tomi, Masatoshi; Nakashima, Emi

    2014-05-01

    Betaine uptake is induced by hypertonic stress in a placental trophoblast cell line, and involvement of amino acid transport system A was proposed. Here, we aimed to identify the subtype(s) of system A that mediates hypertonicity-induced betaine uptake. Measurement of [(14)C]betaine uptake by HEK293 cells transiently transfected with human or rat sodium-coupled neutral amino acid transporters (SNATs), SNAT1, SNAT2 and SNAT4 revealed that only human and rat SNAT2 have betaine uptake activity. The Michaelis constants (Km) of betaine uptake by human and rat SNAT2 were estimated to be 5.3 mM and 4.6 mM, respectively. Betaine exclusively inhibited the uptake activity of SNAT2 among the rat system A subtypes. We found that rat SNAT1, SNAT2 and SNAT4 were expressed at the mRNA level under isotonic conditions, while expression of SNAT2 and SNAT4 was induced by hypertonicity in TR-TBT 18d-1 cells. Western blot analyses revealed that SNAT2 expression on plasma membrane of TR-TBT 18d-1 cells was more potently induced by hypertonicity than that in total cell lysate. Immunocytochemistry confirmed the induction of SNAT2 expression in TR-TBT 18d-1 cells exposed to hypertonic conditions and indicated that SNAT2 was localized on the plasma membrane in these cells. Our results indicate that SNAT2 transports betaine, and that tonicity-sensitive SNAT2 expression may be involved in regulation of betaine concentration in placental trophoblasts.

  16. The role of endocytosis in the uptake and intracellular trafficking of PepFect14-nucleic acid nanocomplexes via class A scavenger receptors.

    PubMed

    Juks, Carmen; Padari, Kärt; Margus, Helerin; Kriiska, Asko; Etverk, Indrek; Arukuusk, Piret; Koppel, Kaida; Ezzat, Kariem; Langel, Ülo; Pooga, Margus

    2015-12-01

    Cell penetrating peptides are efficient tools to deliver various bioactive cargos into cells, but their exact functioning mechanism is still debated. Recently, we showed that a delivery peptide PepFect14 condenses oligonucleotides (ON) into negatively charged nanocomplexes that are taken up by cells via class A scavenger receptors (SR-As). Here we unraveled the uptake mechanism and intracellular trafficking of PF14-ON nanocomplexes in HeLa cells. Macropinocytosis and caveolae-mediated endocytosis are responsible for the intracellular functionality of nucleic acids packed into nanocomplexes. However, only a negligible fraction of the complexes were trafficked to endoplasmic reticulum or Golgi apparatus - the common destinations of caveolar endocytosis. Neither were the PF14-SCO nanocomplexes routed to endo-lysosomal pathway, and they stayed in vesicles with slightly acidic pH, which were not marked with LysoSensor. "Naked" ON, in contrary, was rapidly targeted to acidic vesicles and lysosomes. The transmission electron microscopy analysis of interactions between SR-As and PF14-ON nanocomplexes on ultrastructural level revealed that nanocomplexes localized on the plasma membrane in close proximity to SR-As and their colocalization is retained in cells, suggesting that PF14-ON complexes associate with targeted receptors.

  17. High-Speed Microdialysis-Capillary Electrophoresis Assays for Measuring Branched Chain Amino Acid Uptake in 3T3-L1 cells.

    PubMed

    Harstad, Rachel K; Bowser, Michael T

    2016-08-16

    We have developed a high-throughput microdialysis-capillary electrophoresis (MD-CE) assay for monitoring branched chain amino acid (BCAA) uptake/release dynamics in 3T3-L1 cells. BCAAs (i.e., isoleucine, leucine, and valine) and their downstream metabolites (i.e., alanine, glutamine, and glutamate) are important indicators of adipocyte lipogenesis. To perform an analysis, amino acids were sampled using microdialysis, fluorescently labeled in an online reaction, separated using CE, and detected using laser-induced fluorescence (LIF) in a sheath flow cuvette. Separation conditions were optimized for the resolution of the BCAAs isoleucine, leucine, and valine, as well as 13 other amino acids, including ornithine, alanine, glutamine, and glutamate. CE separations were performed in <30 s, and the temporal resolution of the online MD-CE assay was <60 s. Limits of detection (LOD) were 400, 200, and 100 nM for isoleucine, leucine, and valine, respectively. MD-CE dramatically improved throughput in comparison to traditional offline CE methods, allowing 8 replicates of 15 samples (i.e., 120 analyses) to be assayed in <120 min. The MD-CE assay was used to assess the metabolism dynamics of 3T3-L1 cells over time, confirming the utility of the assay. PMID:27398773

  18. Capillary electrophoresis with laser-induced fluorescence detection for studying amino acid uptake by yeast during beer fermentation.

    PubMed

    Turkia, Heidi; Sirén, Heli; Penttilä, Merja; Pitkänen, Juha-Pekka

    2015-01-01

    The amino acid composition of cultivation broth is known to affect the biomass accumulation, productivity, and vitality of yeast during cultivation. A separation method based on capillary electrophoresis with laser-induced fluorescence (LIF) detection was developed for the determination of amino acid consumption by Saccharomyces cerevisiae during beer fermentation. Intraday relative standard deviations were less than 2.1% for migration times and between 2.9% and 9.9% for peak areas. Interday relative standard deviations were less than 2.5% for migration times and between 4.4% and 18.9% for peak areas. The quantification limit was even as low as 62.5 pM which equals to below attomole level detection. The method was applied to study the rate of amino acid utilization during beer fermentation.

  19. Salicylic acid involved in the regulation of nutrient elements uptake and oxidative stress in Vallisneria natans (Lour.) Hara under Pb stress.

    PubMed

    Wang, Chao; Zhang, Songhe; Wang, Peifang; Hou, Jun; Qian, Jin; Ao, Yanhui; Lu, Jie; Li, Li

    2011-06-01

    In this study, the alterations in nutrient elements content, reactive oxygen species level and antioxidant response were studied in leaves of Vallisneria natans (Lour.) Hara exposed to salicylic acid (SA, 10 or 100 μM), or Pb (50 μM) or their combinations for 4d. No significant alterations in Mn and Ca content were observed but content of Cu, Zn, Fe and P decreased in plants exposed to SA alone. SA application inhibited the uptake of Pb and partially reversed Pb-induced the alterations in Mn, Ca and Fe content in leaves of V. natans exposed to 50 μM Pb. The decreased chlorophyll (a+b) and increased malondialdehyde and O(2-) and H(2)O(2) content were detected in plants exposed to 100 μM SA, 50 μM Pb, 10 μM SA+50 μM Pb or 100 μM SA+50 μM Pb. Application SA partially inhibited Pb-induced the increase of malondialdehyde, O(2-) and H(2)O(2) content. 100 μM SA decreased the activity of NADH oxidase and the content of non-protein thiols, carotenoids and ascorbic acid and increased the content of dehydroascorbate in plants treated with or without Pb. SA alone decreased the ascorbate peroxidase activity and increased the catalase and peroxidase activity, while SA application increased catalase activity but had no significant effect on ascorbate peroxidase and peroxidase activity in V. natans exposed to Pb. The results indicate that SA involves in the regulation of Pb uptake, nutrient balance and oxidative stress. PMID:21377190

  20. Androgen uptake in the female reproductive system of a nonhuman primate

    SciTech Connect

    Weaker, F.J.; Sheridan, P.J.

    1981-07-15

    The nuclear uptake and retention of /sup 3/H-dehydrotestosterone (/sup 3/H-DHT) were studied in the reproductive organs of the female rhesus monkey by autoradiography. Ovariectomized and adrenalectomized adult female monkeys were injected with 1 microgram of /sup 3/H-DHT (107 Ci/mmole) and were exsanguinated 1 hour later. The uterus, cervix, vagina, and fimbriae of the fallopian tubes were removed and processed for autoradiography. Localization of the androgen was observed in the nuclei of fibroblasts, but not in the nuclei of smooth muscle and tissues of the blood vessels, of all four organs. The uptake of androgen by the epithelium varied for each organ. The simple columnar epithelium of the fallopian tube demonstrated nuclear labeling, but the epithelium of the uterus did not. The cells of the germinative layer of the stratified squamous epithelium of both the cervix and vagina exhibited nuclear concentration of label; however, the simple columnar epithelium of the cervix contiguous with the uterus was free of label. The results suggest that androgens may have a physiologic role in the female reproductive organs, and that the therapeutic effect of drugs such as danazol may be mediated via an androgen receptor.

  1. Lysophosphatidic Acid signaling in the nervous system.

    PubMed

    Yung, Yun C; Stoddard, Nicole C; Mirendil, Hope; Chun, Jerold

    2015-02-18

    The brain is composed of many lipids with varied forms that serve not only as structural components but also as essential signaling molecules. Lysophosphatidic acid (LPA) is an important bioactive lipid species that is part of the lysophospholipid (LP) family. LPA is primarily derived from membrane phospholipids and signals through six cognate G protein-coupled receptors (GPCRs), LPA1-6. These receptors are expressed on most cell types within central and peripheral nervous tissues and have been functionally linked to many neural processes and pathways. This Review covers a current understanding of LPA signaling in the nervous system, with particular focus on the relevance of LPA to both physiological and diseased states. PMID:25695267

  2. Is nutrient uptake by plant roots sensitive to the rate of mass flow? Reappraisal of an old chestnut for spatially distributed root systems

    NASA Astrophysics Data System (ADS)

    McMurtrie, R. E.; Näsholm, T.

    2015-12-01

    Numerous modelling papers have considered the contribution of mass flow to nutrient uptake by a single plant root, but few have evaluated its contribution at the scale of an entire root system. We derive equations for nitrogen (N) influx per unit root surface area (J) and N uptake by a single root (U) as functions of soil nitrogen supply, root-length density (RLD) and the velocity of water at the root surface (vo). This model of N uptake by a single root can be used to evaluate N uptake by an entire root system if spatial distributions are known for soil N supply, root biomass and water-uptake velocity. In this paper we show that spatial distributions of RLD and vo can be estimated simultaneously under an optimisation hypothesis (MaxNup, McMurtrie et al. 2012), according to which total root mass and total water uptake are distributed vertically in order to maximise total N uptake. The MaxNup hypothesis leads to equations for optimal vertical profiles of RLD, vo, J and U, maximum rooting depth and the fraction of total available soil nitrogen taken up by the root system. Predicted values of vo are enhanced at depths where nitrogen influx per unit root surface area (J) is more sensitive to vo and diminished at depths where J is less sensitive to vo. Predicted vo is largest at the base of the root system where RLD is lowest, and is smallest in upper soil layers where RLD is highest. MaxNup thus predicts that water uptake will be distributed preferentially to soil depths where it will enhance nitrogen uptake U; this tendency will amplify the sensitivity of total N uptake to total water uptake, compared with strategies where vo is the same for all roots, or where vo is elevated for roots in upper soil layers. Reference McMurtrie RE, Iversen CM, Dewar RC, Medlyn BE, Näsholm T, Pepper DA, Norby RJ. 2012. Plant root distributions and nitrogen uptake predicted by a hypothesis of optimal root foraging. Ecology and Evolution 2: 1235-1250.

  3. The contribution of SNAT1 to system A amino acid transporter activity in human placental trophoblast

    SciTech Connect

    Desforges, M.; Greenwood, S.L.; Glazier, J.D.; Westwood, M.; Sibley, C.P.

    2010-07-16

    Research highlights: {yields} mRNA levels for SNAT1 are higher than other system A subtype mRNAs in primary human cytotrophoblast. {yields} SNAT1 knockdown in cytotrophoblast cells significantly reduces system A activity. {yields} SNAT1 is a key contributor to system A-mediated amino acid transport in human placenta. -- Abstract: System A-mediated amino acid transport across the placenta is important for the supply of neutral amino acids needed for fetal growth. All three system A subtypes (SNAT1, 2, and 4) are expressed in human placental trophoblast suggesting there is an important biological role for each. Placental system A activity increases as pregnancy progresses, coinciding with increased fetal nutrient demands. We have previously shown SNAT4-mediated system A activity is higher in first trimester than at term, suggesting that SNAT1 and/or SNAT2 are responsible for the increased system A activity later in gestation. However, the relative contribution of each subtype to transporter activity in trophoblast at term has yet to be evaluated. The purpose of this study was to identify the predominant subtype of system A in cytotrophoblast cells isolated from term placenta, maintained in culture for 66 h, by: (1) measuring mRNA expression of the three subtypes and determining the Michaelis-Menten constants for uptake of the system A-specific substrate, {sup 14}C-MeAIB, (2) investigating the contribution of SNAT1 to total system A activity using siRNA. Results: mRNA expression was highest for the SNAT1 subtype of system A. Kinetic analysis of {sup 14}C-MeAIB uptake revealed two distinct transport systems; system 1: K{sub m} = 0.38 {+-} 0.12 mM, V{sub max} = 27.8 {+-} 9.0 pmol/mg protein/20 min, which resembles that reported for SNAT1 and SNAT2 in other cell types, and system 2: K{sub m} = 45.4 {+-} 25.0 mM, V{sub max} = 1190 {+-} 291 pmol/mg protein/20 min, which potentially represents SNAT4. Successful knockdown of SNAT1 mRNA using target-specific si

  4. Peptide-based delivery of nucleic acids: design, mechanism of uptake and applications to splice-correcting oligonucleotides.

    PubMed

    Abes, S; Moulton, H; Turner, J; Clair, P; Richard, J P; Iversen, P; Gait, M J; Lebleu, B

    2007-02-01

    CPPs (cell-penetrating peptides) have given rise to much interest for the delivery of biomolecules such as peptides, proteins or ONs (oligonucleotides). CPPs and their conjugates were initially thought to translocate through the cell membrane by a non-endocytotic mechanism which has recently been re-evaluated. Basic-amino-acid-rich CPPs first interact with cell-surface proteoglycans before being internalized by endocytosis. Sequestration and degradation in endocytotic vesicles severely limits the cytoplasmic and nuclear delivery of the conjugated biomolecules. Accordingly, splicing correction by CPP-conjugated steric-block ON analogues is inefficient in the absence of endosomolytic agents. New arginine-rich CPPs allowing efficient splicing correction by conjugated PNAs (peptide nucleic acids) or PMO (phosphorodiamidate morpholino oligomer) steric blockers in the absence of endosomolytic agents have recently been defined in our group and are currently being characterized. They offer promising leads for the development of efficient cellular delivery vectors for therapeutic steric-block ON analogues.

  5. Hydroxybenzoic acid isomers and the cardiovascular system

    PubMed Central

    2014-01-01

    Today we are beginning to understand how phytochemicals can influence metabolism, cellular signaling and gene expression. The hydroxybenzoic acids are related to salicylic acid and salicin, the first compounds isolated that have a pharmacological activity. In this review we examine how a number of hydroxyphenolics have the potential to ameliorate cardiovascular problems related to aging such as hypertension, atherosclerosis and dyslipidemia. The compounds focused upon include 2,3-dihydroxybenzoic acid (Pyrocatechuic acid), 2,5-dihydroxybenzoic acid (Gentisic acid), 3,4-dihydroxybenzoic acid (Protocatechuic acid), 3,5-dihydroxybenzoic acid (α-Resorcylic acid) and 3-monohydroxybenzoic acid. The latter two compounds activate the hydroxycarboxylic acid receptors with a consequence there is a reduction in adipocyte lipolysis with potential improvements of blood lipid profiles. Several of the other compounds can activate the Nrf2 signaling pathway that increases the expression of antioxidant enzymes, thereby decreasing oxidative stress and associated problems such as endothelial dysfunction that leads to hypertension as well as decreasing generalized inflammation that can lead to problems such as atherosclerosis. It has been known for many years that increased consumption of fruits and vegetables promotes health. We are beginning to understand how specific phytochemicals are responsible for such therapeutic effects. Hippocrates’ dictum of ‘Let food be your medicine and medicine your food’ can now be experimentally tested and the results of such experiments will enhance the ability of nutritionists to devise specific health-promoting diets. PMID:24943896

  6. Hydroxybenzoic acid isomers and the cardiovascular system.

    PubMed

    Juurlink, Bernhard H J; Azouz, Haya J; Aldalati, Alaa M Z; AlTinawi, Basmah M H; Ganguly, Paul

    2014-01-01

    Today we are beginning to understand how phytochemicals can influence metabolism, cellular signaling and gene expression. The hydroxybenzoic acids are related to salicylic acid and salicin, the first compounds isolated that have a pharmacological activity. In this review we examine how a number of hydroxyphenolics have the potential to ameliorate cardiovascular problems related to aging such as hypertension, atherosclerosis and dyslipidemia. The compounds focused upon include 2,3-dihydroxybenzoic acid (Pyrocatechuic acid), 2,5-dihydroxybenzoic acid (Gentisic acid), 3,4-dihydroxybenzoic acid (Protocatechuic acid), 3,5-dihydroxybenzoic acid (α-Resorcylic acid) and 3-monohydroxybenzoic acid. The latter two compounds activate the hydroxycarboxylic acid receptors with a consequence there is a reduction in adipocyte lipolysis with potential improvements of blood lipid profiles. Several of the other compounds can activate the Nrf2 signaling pathway that increases the expression of antioxidant enzymes, thereby decreasing oxidative stress and associated problems such as endothelial dysfunction that leads to hypertension as well as decreasing generalized inflammation that can lead to problems such as atherosclerosis. It has been known for many years that increased consumption of fruits and vegetables promotes health. We are beginning to understand how specific phytochemicals are responsible for such therapeutic effects. Hippocrates' dictum of 'Let food be your medicine and medicine your food' can now be experimentally tested and the results of such experiments will enhance the ability of nutritionists to devise specific health-promoting diets. PMID:24943896

  7. Threonine deprivation rapidly activates the system A amino acid transporter in primary cultures of rat neurons from the essential amino acid sensor in the anterior piriform cortex.

    PubMed

    Blais, Anne; Huneau, Jean-François; Magrum, Linda J; Koehnle, Thomas J; Sharp, James W; Tomé, Daniel; Gietzen, Dorothy W

    2003-07-01

    Omnivores show recognition of essential (indispensable) amino acid deficiency by changing their feeding behavior within 20 min, yet the cellular mechanisms of amino acid sensation in eukaryotes are poorly understood. The anterior piriform cortex (APC) of the brain in rats or its analog in birds likely houses the in vivo amino acid chemosensor. Because amino acid transporters adapt rapidly to essential amino acid deficiency in several cell models, we hypothesized that activation of electrogenic amino acid transport in APC neurons might contribute to the function of the amino acid sensor. We evaluated transport systems in primary cultures of neurons from the APC, hippocampus and cerebellum, or glia, incubated in complete or threonine-devoid (deficient) medium. After 10 min in deficient medium, uptake of threonine or a system A-selective substrate, methyl amino-isobutyric acid, was increased 60% in APC neurons only (P < 0.05). These results demonstrated upregulation of system A, an electrogenic amino acid-sodium symporter. This depletion-induced activation required sodium, intact intracellular trafficking, and phosphorylation of signal transduction-related kinases. Efflux studies showed that other transporter types were functional in the APC; they appeared to be altered dynamically in threonine-deficient cells in response to rapid increases in system A activity. The present data provided support for the chemical sensitivity of the APC and its role as the brain area housing the indispensable amino acid chemosensor. They also showed a region-specific, phosphorylation-dependent activation of the system A transporter in the brain in response to threonine deficiency.

  8. Acid-base responses to feeding and intestinal Cl- uptake in freshwater- and seawater-acclimated killifish, Fundulus heteroclitus, an agastric euryhaline teleost.

    PubMed

    Wood, Chris M; Bucking, Carol; Grosell, Martin

    2010-08-01

    Marine teleosts generally secrete basic equivalents (HCO(3)(-)) and take up Na(+) and Cl(-) in the intestine so as to promote absorption of H(2)O. However, neither the integration of these functions with feeding nor the potential role of the gut in ionoregulation and acid-base balance in freshwater have been well studied. The euryhaline killifish (Fundulus heteroclitus) is unusual in lacking both an acid-secreting stomach and a mechanism for Cl(-) uptake at the gills in freshwater. Responses to a satiation meal were evaluated in both freshwater- and seawater-acclimated killifish. In intact animals, there was no change in acid or base flux to the external water after the meal, in accord with the absence of any post-prandial alkaline tide in the blood. Indeed, freshwater animals exhibited a post-prandial metabolic acidosis ('acidic tide'), whereas seawater animals showed no change in blood acid-base status. In vitro gut sac experiments revealed a substantially higher rate of Cl(-) absorption by the intestine in freshwater killifish, which was greatest at 1-3 h after feeding. The Cl(-) concentration of the absorbate was higher in preparations from freshwater animals than from seawater killifish and increased with fasting. Surprisingly, net basic equivalent secretion rates were also much higher in preparations from freshwater animals, in accord with the 'acidic tide'; in seawater preparations, they were lowest after feeding and increased with fasting. Bafilomycin (1 micromol l(-1)) promoted an 80% increase in net base secretion rates, as well as in Cl(-) and fluid absorption, at 1-3 h post-feeding in seawater preparations only, explaining the difference between freshwater and seawater fish. Preparations from seawater animals at 1-3 h post-feeding also acidified the mucosal saline, and this effect was associated with a marked rise in P(CO(2)), which was attenuated by bafilomycin. Measurements of chyme pH from intact animals confirmed that intestinal fluid (chyme) pH and

  9. Preparation of poly(β-L-malic acid)-based charge-conversional nanoconjugates for tumor-specific uptake and cellular delivery.

    PubMed

    Zhou, Qing; Yang, Tiehong; Qiao, Youbei; Guo, Songyan; Zhu, Lin; Wu, Hong

    2015-01-01

    In this study, a multifunctional poly(β-L-malic acid)-based nanoconjugate with a pH-dependent charge conversional characteristic was developed for tumor-specific drug delivery. The short branched polyethylenimine-modified poly(β-L-malic acid) (PEPM) was first synthesized. Then, the fragment HAb18 F(ab')2 and 2,3-dimethylmaleic anhydride were covalently attached to the PEPM to form the nanoconjugate, HDPEPM. In this nanoconjugate, the 2,3-dimethylmaleic anhydride, the shielding group, could shield the positive charge of the conjugate at pH 7.4, while it was selectively hydrolyzed in the tumor extracellular space (pH 6.8) to expose the previously-shielded positive charge. To study the anticancer activity, the anticancer drug, doxorubicin, was covalently attached to the nanoconjugate. The doxorubicin-loaded HDPEPM nanoconjugate was able to efficiently undergo a quick charge conversion from -11.62 mV to 9.04 mV in response to the tumor extracellular pH. The electrostatic interaction between the positively charged HDPEPM nanoconjugates and the negatively charged cell membrane significantly enhanced their cellular uptake, resulting in the enhanced anticancer activity. Also, the tumor targetability of the nanoconjugates could be further improved via the fragment HAb18 F(ab')2 ligand-receptor-mediated tumor cell-specific endocytosis.

  10. Acidity-promoted cellular uptake and drug release mediated by amine-functionalized block polycarbonates prepared via one-shot ring-opening copolymerization.

    PubMed

    Wang, Hua-Fen; Jia, Hui-Zhen; Chu, Yan-Feng; Feng, Jun; Zhang, Xian-Zheng; Zhuo, Ren-Xi

    2014-04-01

    This paper reports a drug nanovehicle self-assembled from an amine-functionalized block copolymer poly(6,14-dimethyl-1,3,9,11-tetraoxa-6,14-diaza-cyclohexadecane-2,10-dione)-block-poly(1,3-dioxepan-2-one) (PADMC-b-PTeMC), which is prepared by controlable ring-opening block copolymerization attractively in a "one-shot feeding" pathway. The copolymers display high cell-biocompatibility with no apparent cytotoxicities detected in 293T and HeLa cells. Due to their amphiphilic nature, PADMC-b-PTeMC copolymers can self-assemble into nanosized micelles capable of loading anticancer drugs such as camptothecin (CPT) and doxorubicin (DOX). In particular, the outer PADMC shell endows the PADMC-b-PTeMC nanomicelles with pH-dependent control over the micellar morphology, cell uptake efficiency, and the drug release pattern. Confocal inspection reveals the remarkably enhanced cellular internalization of drug loaded micelles by cancerous HeLa cells at relatively lower pH 5.8 simulating the mildly acid microenvironment in tumors. Along with the acidity-triggered volume expansion of micelles, an accelerated CPT release in vitro occurs. The obtained results adumbrate the possibility of completely biodegradable PADMC-b-PTeMC as pH-sensitive drug carriers for tumor chemotherapy.

  11. Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems

    SciTech Connect

    Schuytema, G.S.; Krawczyk, D.F.; Griffis, W.L.; Nebeker, A.V.; Robideaux, M.L.

    1990-01-01

    Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms.

  12. Cationic Amino Acid Uptake Constitutes a Metabolic Regulation Mechanism and Occurs in the Flagellar Pocket of Trypanosoma cruzi

    PubMed Central

    Bouvier, León A.; Cámara, María de los Milagros; Montserrat, Javier; Pereira, Claudio A.

    2012-01-01

    Trypanosomatids' amino acid permeases are key proteins in parasite metabolism since they participate in the adaptation of parasites to different environments. Here, we report that TcAAP3, a member of a Trypanosoma cruzi multigene family of permeases, is a bona fide arginine transporter. Most higher eukaryotic cells incorporate cationic amino acids through a single transporter. In contrast, T. cruzi can recognize and transport cationic amino acids by mono-specific permeases since a 100-fold molar excess of lysine could not affect the arginine transport in parasites that over-express the arginine permease (TcAAP3 epimastigotes). In order to test if the permease activity regulates downstream processes of the arginine metabolism, the expression of the single T. cruzi enzyme that uses arginine as substrate, arginine kinase, was evaluated in TcAAP3 epimastigotes. In this parasite model, intracellular arginine concentration increases 4-folds and ATP level remains constant until cultures reach the stationary phase of growth, with decreases of about 6-folds in respect to the controls. Interestingly, Western Blot analysis demonstrated that arginine kinase is significantly down-regulated during the stationary phase of growth in TcAAP3 epimastigotes. This decrease could represent a compensatory mechanism for the increase in ATP consumption as a consequence of the displacement of the reaction equilibrium of arginine kinase, when the intracellular arginine concentration augments and the glucose from the medium is exhausted. Using immunofluorescence techniques we also determined that TcAAP3 and the specific lysine transporter TcAAP7 co-localize in a specialized region of the plasma membrane named flagellar pocket, staining a single locus close to the flagellar pocket collar. Taken together these data suggest that arginine transport is closely related to arginine metabolism and cell energy balance. The clinical relevance of studying trypanosomatids' permeases relies on the

  13. Drug repurposing: sulfasalazine sensitizes gliomas to gamma knife radiosurgery by blocking cystine uptake through system Xc-, leading to glutathione depletion.

    PubMed

    Sleire, L; Skeie, B S; Netland, I A; Førde, H E; Dodoo, E; Selheim, F; Leiss, L; Heggdal, J I; Pedersen, P-H; Wang, J; Enger, P Ø

    2015-12-01

    Glioblastomas (GBMs) are aggressive brain tumors that always recur after radiotherapy. Cystine, mainly provided by the system X(c)(-) antiporter, is a requirement for glioma cell synthesis of glutathione (GSH) which has a critical role in scavenging free radicals, for example, after radiotherapy. Thus, we hypothesized that the X(c)(-)-inhibitor sulfasalazine (SAS) could potentiate the efficacy of radiotherapy against gliomas. Here, we show that the catalytic subunit of system X(c)(-), xCT, was uniformly expressed in a panel of 30 human GBM biopsies. SAS treatment significantly reduced cystine uptake and GSH levels, whereas it significantly increased the levels of reactive oxygen species (ROS) in glioma cells in vitro. Furthermore, SAS and radiation synergistically increased DNA double-strand breaks and increased glioma cell death, whereas adding the antioxidant N-acetyl-L-cysteine (NAC) reversed cell death. Moreover, SAS and gamma knife radiosurgery (GKRS) synergistically prolonged survival in nude rats harboring human GBM xenografts, compared with controls or either treatment alone. In conclusion, SAS effectively blocks cystine uptake in glioma cells in vitro, leading to GSH depletion and increased ROS levels, DNA damage and cell death. Moreover, it potentiates the anti-tumor efficacy of GKRS in rats with human GBM xenografts, providing a survival benefit. Thus, SAS may have a role as a radiosensitizer to enhance the efficacy of current radiotherapies for glioma patients.

  14. Benzene Uptake and Glutathione S-transferase T1 Status as Determinants of S-Phenylmercapturic Acid in Cigarette Smokers in the Multiethnic Cohort

    PubMed Central

    Haiman, Christopher A.; Patel, Yesha M.; Stram, Daniel O.; Carmella, Steven G.; Chen, Menglan; Wilkens, Lynne R.; Le Marchand, Loic; Hecht, Stephen S.

    2016-01-01

    Research from the Multiethnic Cohort (MEC) demonstrated that, for the same quantity of cigarette smoking, African Americans and Native Hawaiians have a higher lung cancer risk than Whites, while Latinos and Japanese Americans are less susceptible. We collected urine samples from 2,239 cigarette smokers from five different ethnic groups in the MEC and analyzed each sample for S-phenylmercapturic acid (SPMA), a specific biomarker of benzene uptake. African Americans had significantly higher (geometric mean [SE] 3.69 [0.2], p<0.005) SPMA/ml urine than Whites (2.67 [0.13]) while Japanese Americans had significantly lower levels