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Sample records for active nutrient uptake

  1. Microbial Enzyme Activity, Nutrient Uptake, and Nutrient Limitation in Forested Streams

    EPA Science Inventory

    We measured NH4 + and PO4 -3 uptake length (Sw), uptake velocity (Vf), uptake rate (U), biofilm enzyme activity (BEA), and channel geomorphology in streams draining forested catchments in the Northwestern (Northern California Coast Range and Cascade Mountains) and Southeastern (A...

  2. Effects of ammonium and nitrate on nutrient uptake and activity of nitrogen assimilating enzymes in western hemlock

    SciTech Connect

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

    1993-01-01

    Western hemlock seedlings were grown in nutrient solutions with ammonium, nitrate or ammonium plus nitrate as nitrogen sources. The objectives were to examine (1) possible selectivity for ammonium or nitrate as an N source, (2) the maintenance of charge balance during ammonium and nitrate uptake, and (3) the activity of the nitrogen assimilating enzymes, nitrate reductase, glutamine synthetase, and glutamine dehydrogenase, in relation to the uptake of different nitrogen sources. The uptake studies revealed that western hemlock takes up ammonium faster than nitrate and that ammonium partially inhibits nitrate uptake. Nitrate reductase activity varied with nitrate availability in root tissue, but showed no response in needles, indicating that most nitrate is reduced in the roots. Results indicate that western hemlock may be adapted to sites where NH(4+) is the predominate N source.

  3. A new compensated root water and nutrient uptake model implemented in HYDRUS programs

    NASA Astrophysics Data System (ADS)

    Simunek, Jiri; Hopmans, Jan W.; Lazarovitch, Naftali

    2010-05-01

    Plant root water and nutrient uptake is one of the most important processes in subsurface unsaturated flow and transport modeling, as root uptake controls actual plant evapotranspiration, water recharge and nutrient leaching to the groundwater. Root water uptake in unsaturated flow models is usually uncompensated and nutrient uptake is simulated assuming that all uptake is passive. We present a new compensated root water and nutrient uptake model, implemented in HYDRUS programs. The so-called root adaptability factor (Jarvis, 1989) is used to represent a threshold value above which reduced root water or nutrient uptake in water- or nutrient-stressed parts of the root zone is fully compensated for by increased uptake in other soil regions that are less stressed. Using a critical value of the water stress index, water uptake compensation is proportional to the water stress response function. Total root nutrient uptake is determined from the total of active and passive nutrient uptake. The partitioning between passive and active uptake is controlled by the a priori defined concentration value c_max. Passive nutrient uptake is simulated by multiplying root water uptake with the dissolved nutrient concentration, for soil solution concentration values below c_max. Passive nutrient uptake is thus zero when c_max is equal to zero. As the active nutrient uptake is obtained from the difference between plant nutrient demand and passive nutrient uptake (using Michaelis-Menten kinetics), the presented model thus implies that reduced passive nutrient uptake is compensated for by active nutrient uptake. In addition, the proposed root uptake model includes compensation for active nutrient uptake, in a similar way as used for root water uptake. The proposed root water and nutrient uptake model is demonstrated by several hypothetical and real examples, for plants supplied by water due to capillary rise from groundwater and surface drip irrigation.

  4. Effects of nitrogen fertilization on soil nutrient concentration and phosphatase activity and forage nutrient uptake from a grazed pasture system.

    PubMed

    Dillard, Sandra Leanne; Wood, Charles Wesley; Wood, Brenda Hall; Feng, Yucheng; Owsley, Walter Frank; Muntifering, Russell Brian

    2015-05-01

    Over a 3-year period, the effect of differing N-application regimes on soil extractable-P concentration, soil phosphatase activity, and forage P uptake in a P-enriched grazed-pasture system was investigated. In the fall of each year, six 0.28-ha plots were overseeded with triticale ( × Triticosecale rimpaui Wittm.) and crimson clover (Trifolium incarnatum) into a tall fescue (Lolium arundinacea)/bermudagrass (Cynodon dactylon) sod and assigned to 1 of 3 N-fertilizer treatments (n = 2): 100% of N recommendation in a split application (100N), 50% in a single application (50N), and 0% of N recommendation (0N) for triticale. Cattle commenced grazing the following spring and grazed until May. In the summer, plots were overseeded with cowpea (Vigna unguiculata), fertilized at the same rates by reference to N recommendations for bermudagrass, and grazed by cattle until September. There were no effects of N fertilization on soil phosphatase activity, electrical conductivity, or concentrations of water-soluble P. Concentrations of extractable P decreased in plots receiving 50N, but increasing N fertilization to 100N resulted in no further reduction in extractable P. Forage biomass, foliar P concentrations, and forage P mass were not affected by N fertilization rates at the plant-community level, but responses were observed within individual forage species. Results are interpreted to mean that N fertilization at 50% of the agronomic recommendation for the grass component can increase forage P mass of specific forages and decrease soil extractable P, thus providing opportunity for decreasing P losses from grazed pasture.

  5. Dynamic model of flexible phytoplankton nutrient uptake

    PubMed Central

    Bonachela, Juan A.; Raghib, Michael; Levin, Simon A.

    2011-01-01

    The metabolic machinery of marine microbes can be remarkably plastic, allowing organisms to persist under extreme nutrient limitation. With some exceptions, most theoretical approaches to nutrient uptake in phytoplankton are largely dominated by the classic Michaelis–Menten (MM) uptake functional form, whose constant parameters cannot account for the observed plasticity in the uptake apparatus. Following seminal ideas by earlier researchers, we propose a simple cell-level model based on a dynamic view of the uptake process whereby the cell can regulate the synthesis of uptake proteins in response to changes in both internal and external nutrient concentrations. In our flexible approach, the maximum uptake rate and nutrient affinity increase monotonically as the external nutrient concentration decreases. For low to medium nutrient availability, our model predicts uptake and growth rates larger than the classic MM counterparts, while matching the classic MM results for large nutrient concentrations. These results have important consequences for global coupled models of ocean circulation and biogeochemistry, which lack this regulatory mechanism and are thus likely to underestimate phytoplankton abundances and growth rates in oligotrophic regions of the ocean. PMID:22143781

  6. Does cluster-root activity benefit nutrient uptake and growth of co-existing species?

    PubMed

    Muler, Ana L; Oliveira, Rafael S; Lambers, Hans; Veneklaas, Erik J

    2014-01-01

    Species that inhabit phosphorus- (P) and micronutrient-impoverished soils typically have adaptations to enhance the acquisition of these nutrients, for example cluster roots in Proteaceae. However, there are several species co-occurring in the same environment that do not produce similar specialised roots. This study aims to investigate whether one of these species (Scholtzia involucrata) can benefit from the mobilisation of P or micronutrients by the cluster roots of co-occurring Banksia attenuata, and also to examine the response of B. attenuata to the presence of S. involucrata. We conducted a greenhouse experiment, using a replacement series design, where B. attenuata and S. involucrata shared a pot at proportions of 2:0, 1:2 and 0:4. S. involucrata plants grew more in length, were heavier and had higher manganese (Mn) concentrations in their young leaves when grown next to one individual of B. attenuata and one individual of S. involucrata than when grown with three conspecifics. All S. involucrata individuals were colonised by arbuscular mycorrhizal fungi, and possibly Rhizoctonia. Additionally, P concentration was higher in the young leaves of B. attenuata when grown with another B. attenuata than when grown with two individuals of S. involucrata, despite the smaller size of the S. involucrata individuals. Our results demonstrate that intraspecific competition was stronger than interspecific competition for S. involucrata, but not for B. attenuata. We conclude that cluster roots of B. attenuata facilitate the acquisition of nutrients by neighbouring shrubs by making P and Mn more available for their neighbours.

  7. Effects of cerium oxide nanoparticles on soil enzymatic activities and wheat grass nutrients uptake

    NASA Astrophysics Data System (ADS)

    Li, Biting; Chen, Yirui; Bai, Lingyun; Jacobson, Astrid; Darnault, Christophe

    2015-04-01

    The US National Science Foundation estimated that the use of nanomaterials and nanotechnology would reach a global market value of 1 million this year. Concomitant with the wide applications of nanoparticles is an increasing risk of adverse effects to the environment and human health. As a common nanomaterial used as a fuel catalyst and polish material, cerium (IV) oxide nanoparticles (CeO2 NP) were tested for their potential impact on soil health and plant growth. Through exposure by air, water, and solid deposition, nanoparticles may accumulate in soils and impact agricultural systems. The objectives of this research were to determine whether CeO2 NPs affect the growth of wheat grass and selected soil enzyme activities chose as indicators of soil health. Wheat grass was grown in plant boxes containing CeO2 NPs mixed with agricultural soil at different concentrations. Two control groups were included: one consisting of soil with plants but no CeO2 NPs, and one containing only soil, i.e., no NP or wheat plants added. The plants were grown for 10 weeks and harvested every two weeks in a laboratory under sodium growth lights. At the end of the each growing period, two weeks, soils were assayed for phosphatase, β-glucosidase, and urease activities, and NPK values. Spectrophotometer analyses were used to assess enzyme activities, and NPK values were tested by Clemson Agricultural Center. Wheat yields were estimated by shoot and root lengths and weights.

  8. Through form to function: root hair development and nutrient uptake

    NASA Technical Reports Server (NTRS)

    Gilroy, S.; Jones, D. L.

    2000-01-01

    Root hairs project from the surface of the root to aid nutrient and water uptake and to anchor the plant in the soil. Their formation involves the precise control of cell fate and localized cell growth. We are now beginning to unravel the complexities of the molecular interactions that underlie this developmental regulation. In addition, after years of speculation, nutrient transport by root hairs has been demonstrated clearly at the physiological and molecular level, with evidence for root hairs being intense sites of H(+)-ATPase activity and involved in the uptake of Ca(2+), K(+), NH(4)(+), NO(3)(-), Mn(2+), Zn(2+), Cl(-) and H(2)PO(4)(-).

  9. Endocytotic uptake of nutrients in carnivorous plants.

    PubMed

    Adlassnig, Wolfram; Koller-Peroutka, Marianne; Bauer, Sonja; Koshkin, Edith; Lendl, Thomas; Lichtscheidl, Irene K

    2012-07-01

    Carnivorous plants trap, digest and absorb animals in order to supplement their mineral nutrition. Nutrients absorbed by the plant include different nitrogen species, phosphate, potassium, trace elements and small organic compounds. Uptake is usually thought to be performed via specific channels, but this study provides evidence that endocytosis is involved as well. Traps of the carnivorous plants Nepenthes coccinea, Nepenthes ventrata, Cephalotus follicularis, Drosophyllum lusitanicum, Drosera capensis, Dionaea muscipula, Aldrovanda vesiculosa, Genlisea violacea × lobata, Sarracenia psittacina and Sarracenia purpurea were stained with methylene blue in order to identify possible sites of uptake. The permeable parts of the traps were incubated with fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA) and other fluorescent endocytosis markers, combined with the soluble protein BSA or respiratory inhibitors. Uptake was studied by confocal microscopy. In Nepenthes, small fluorescent vesicles became visible 1 h after incubation with FITC-BSA. These vesicles fused to larger compartments within 30 h. A similar behaviour was found in the related genera Drosera, Dionaea, Aldrovanda and Drosophyllum but also in Cephalotus with glands of different evolutionary origin. In Genlisea and Sarracenia, no evidence for endocytosis was found. We propose that in many carnivorous plants, nutrient uptake by carriers is supplemented by endocytosis, which enables absorption and intracellular digestion of whole proteins. The advantage for the plant of reducing secretion of enzymes for extracellular digestion is evident.

  10. The Effect of Catchment Urbanization on Nutrient Uptake and Biofilm Enzyme Activity in Lake Superior (USA) Tributary Streams

    EPA Science Inventory

    We used landscape, habitat, and chemistry variables, along with nutrient spiraling metrics and biofilm extracellular enzyme activity (EEA), to assess the response of streams to the level of urbanization within their catchments. For this study nine streams of similar catchment are...

  11. NUTRIENT UPTAKE: A Microcomputer Program to Predict Nutrient Absorption from Soil by Roots.

    ERIC Educational Resources Information Center

    Oates, Kenneth; Barber, S. A.

    1987-01-01

    Discusses the use of a computer program designed to solve the mathematical model associated with soil nutrient uptake by plant roots and to predict the nutrient uptake. Describes a user-friendly personal computer version of this program. (TW)

  12. Nutrient uptake of peanut genotypes under different water regimes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought is a serious environmental stress limiting growth and productivity in peanut and other crops. Nutrient uptake of peanut is reduced under drought conditions, which reduces yield. The objectives of this study were to investigate nutrient uptake of peanut genotypes in response to drought and ...

  13. Sensory active piperine analogues from Macropiper excelsum and their effects on intestinal nutrient uptake in Caco-2 cells.

    PubMed

    Obst, Katja; Lieder, Barbara; Reichelt, Katharina V; Backes, Michael; Paetz, Susanne; Geißler, Katrin; Krammer, Gerhard; Somoza, Veronika; Ley, Jakob P; Engel, Karl-Heinz

    2017-03-01

    The phytochemical profile of Macropiper excelsum (G.Forst.) Miq. subsp. excelsum (Piperaceae), a shrub which is widespread in New Zealand, was investigated by LC-MS-guided isolation and characterization via HR-ESI-TOF-MS and NMR spectroscopy. The isolated compounds were sensorily evaluated to identify their contribution to the overall taste of the crude extract with sweet, bitter, herbal and trigeminal impressions. Besides the known non-volatile Macropiper compounds, the lignans (+)-diayangambin and (+)-excelsin, four further excelsin isomers, (+)-diasesartemin, (+)-sesartemin, (+)-episesartemin A and B were newly characterized. Moreover, piperine and a number of piperine analogues as well as trans-pellitorine and two homologues, kalecide and (2E,4E)-tetradecadienoic acid N-isobutyl amide were identified in M. excelsum, some of them for the first time. Methyl(2E,4E)-7-(1,3-benzodioxol-5-yl)hepta-2,4-dienoate was identified and characterized for the first time in nature. Sensory analysis of the pure amides indicated that they contributed to the known chemesthetic effects of Macropiper leaves and fruits. Since the pungent piperine has been shown to affect glucose and fatty acid metabolism in vivo in previous studies, piperine itself and four of the isolated compounds, piperdardine, chingchengenamide A, dihydropiperlonguminine, and methyl(2E,4E)-7-(1,3-benzodioxol-5-yl)hepta-2,4-dienoate, were investigated regarding their effects on glucose and fatty acid uptake by enterocyte-like Caco-2 cells, in concentrations ranging from 0.1 to 100 μM. Piperdardine showed the most pronounced effect, with glucose uptake increased by 83 ± 18% at 100 μM compared to non-treated control cells. An amide group seems to be advantageous for glucose uptake stimulation, but not necessarily for fatty acid uptake-stimulating effects of piperine-related compounds.

  14. Coupled Effects of Hyporheic Flow Structure and Metabolic Pattern on Reach-scale Nutrient Uptake

    NASA Astrophysics Data System (ADS)

    Li, A.; Aubeneau, A. F.; Bolster, D.; Tank, J. L.; Packman, A. I.

    2015-12-01

    Co-injections of conservative tracers and nutrients are commonly used to assess net reach-scale nutrient transformation rates and benthic/hyporheic uptake parameters. However, little information is available on spatial metabolic patterns in the benthic and hyporheic regions. Based on observations from real systems, we used particle tracking simulations to explore the effects of localized metabolism on estimates of reach-scale nutrient uptake rates. Metabolism locally depletes nutrient concentrations relative to conservative tracers, causing their concentration profiles of injected nutrients and conservative tracers to diverge. At slow rates of hyporheic exchange relative to rates of metabolism, overall hyporheic nutrient uptake is limited by delivery from the stream, and effective reach-scale nutrient uptake parameters will be controlled by the hyporheic exchange rate. At high rates of hyporheic exchange relative to rates of metabolism, the injected tracer can propagate beyond regions of high microbial activity, which commonly occur near the streambed surface. In this case, the injected tracer may not adequately capture timescales of nutrient replenishment in the most bioactive regions. Reach-scale nutrients uptake rate increases with increasing heterogeneity in local metabolic patterns, altering the shape of breakthrough curves downstream. More observations of hyporheic rates and metabolic patterns are needed to understand how flow heterogeneity and reaction heterogeneity interact to control nutrient dynamics at reach-scale.

  15. Nutrient Uptake Changes in Ascorbate Free Radical-Stimulated Onion Roots.

    PubMed Central

    Gonzalez-Reyes, J. A.; Hidalgo, A.; Caler, J. A.; Palos, R.; Navas, P.

    1994-01-01

    Long-term treatments with ascorbate free radical-stimulated glucose, fucose, sucrose, and nitrate uptake in Allium cepa roots. Glucose and fucose showed saturation kinetics in untreated roots, but after treatment with the ascorbate free radical, uptake was linear with time. Although the rates of nitrate and sucrose uptake increased after treatment with ascorbate free radical, the kinetics were similar to those observed in the controls. Ascorbate and dehydroascorbate inhibited nutrient uptake. The uptake rates for all nutrients increased throughout the 48-h period of pretreatment with ascorbate free radical. During the treatment an increase in the vacuole volume and tonoplast surface area also occurred. These results show the relationship between an increase in vacuolar volume and stimulated nutrient uptake from ascorbate-free radical, resulting in enhanced root elongation. These results suggest that activation of a transplasma membrane redox system by ascorbate-free radical is involved in these responses. PMID:12232078

  16. Optimizing Nutrient Uptake in Biological Transport Networks

    NASA Astrophysics Data System (ADS)

    Ronellenfitsch, Henrik; Katifori, Eleni

    2013-03-01

    Many biological systems employ complex networks of vascular tubes to facilitate transport of solute nutrients, examples include the vascular system of plants (phloem), some fungi, and the slime-mold Physarum. It is believed that such networks are optimized through evolution for carrying out their designated task. We propose a set of hydrodynamic governing equations for solute transport in a complex network, and obtain the optimal network architecture for various classes of optimizing functionals. We finally discuss the topological properties and statistical mechanics of the resulting complex networks, and examine correspondence of the obtained networks to those found in actual biological systems.

  17. Mitochondrial alternative oxidase acts to dampen the generation of active oxygen species during a period of rapid respiration induced to support a high rate of nutrient uptake.

    PubMed

    Yip, Justine Y. H.; Vanlerberghe, Greg C.

    2001-07-01

    When wild type (wt) tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) suspension cells were grown under phosphate (P) limitation, they contained large amounts of mitochondrial alternative oxidase (AOX). When these cells were resupplied with P, there was a large, immediate and sustained stimulation of respiration to support a period of rapid P uptake. Two lines of evidence suggest that the abundant level of AOX present in wt cells contributed to this stimulated rate of respiration. First, when P-limited transgenic antisense tobacco cells (AS8) lacking AOX were resupplied with P, the stimulation of respiration was much less dramatic even though these cells displayed similar rates of P uptake. Second, while the stimulated rate of respiration in AS8 cells was insensitive (as expected) to the AOX inhibitor n-propyl gallate (nPG), much of the stimulated rate of respiration in wt cells could be inhibited by nPG. Given the non-phosphorylating nature of AOX respiration, wt cells required higher rates of electron transport to O2 than AS8 cells to support similar rates of P uptake. The utilization of AOX by wt cells during P uptake was apparently not occurring because the cytochrome (Cyt) pathway alone could not fully support the rate of P uptake, as the respiration of cells lacking AOX (either untreated AS8 cells or wt cells treated with nPG) supported similar rates of P uptake as wt cells with abundant AOX. Rather, we provide in vivo evidence that the utilization of AOX during the period of high respiration supporting P uptake was to dampen the mitochondrial generation of active oxygen species (AOS).

  18. Estimating uncertainty in ambient and saturation nutrient uptake metrics from nutrient pulse releases in stream ecosystems

    DOE PAGES

    Brooks, Scott C.; Brandt, Craig C.; Griffiths, Natalie A.

    2016-10-07

    Nutrient spiraling is an important ecosystem process characterizing nutrient transport and uptake in streams. Various nutrient addition methods are used to estimate uptake metrics; however, uncertainty in the metrics is not often evaluated. A method was developed to quantify uncertainty in ambient and saturation nutrient uptake metrics estimated from saturating pulse nutrient additions (Tracer Additions for Spiraling Curve Characterization; TASCC). Using a Monte Carlo (MC) approach, the 95% confidence interval (CI) was estimated for ambient uptake lengths (Sw-amb) and maximum areal uptake rates (Umax) based on 100,000 datasets generated from each of four nitrogen and five phosphorous TASCC experiments conductedmore » seasonally in a forest stream in eastern Tennessee, U.S.A. Uncertainty estimates from the MC approach were compared to the CIs estimated from ordinary least squares (OLS) and non-linear least squares (NLS) models used to calculate Sw-amb and Umax, respectively, from the TASCC method. The CIs for Sw-amb and Umax were large, but were not consistently larger using the MC method. Despite the large CIs, significant differences (based on nonoverlapping CIs) in nutrient metrics among seasons were found with more significant differences using the OLS/NLS vs. the MC method. Lastly, we suggest that the MC approach is a robust way to estimate uncertainty, as the calculation of Sw-amb and Umax violates assumptions of OLS/NLS while the MC approach is free of these assumptions. The MC approach can be applied to other ecosystem metrics that are calculated from multiple parameters, providing a more robust estimate of these metrics and their associated uncertainties.« less

  19. Estimating uncertainty in ambient and saturation nutrient uptake metrics from nutrient pulse releases in stream ecosystems

    SciTech Connect

    Brooks, Scott C.; Brandt, Craig C.; Griffiths, Natalie A.

    2016-10-07

    Nutrient spiraling is an important ecosystem process characterizing nutrient transport and uptake in streams. Various nutrient addition methods are used to estimate uptake metrics; however, uncertainty in the metrics is not often evaluated. A method was developed to quantify uncertainty in ambient and saturation nutrient uptake metrics estimated from saturating pulse nutrient additions (Tracer Additions for Spiraling Curve Characterization; TASCC). Using a Monte Carlo (MC) approach, the 95% confidence interval (CI) was estimated for ambient uptake lengths (Sw-amb) and maximum areal uptake rates (Umax) based on 100,000 datasets generated from each of four nitrogen and five phosphorous TASCC experiments conducted seasonally in a forest stream in eastern Tennessee, U.S.A. Uncertainty estimates from the MC approach were compared to the CIs estimated from ordinary least squares (OLS) and non-linear least squares (NLS) models used to calculate Sw-amb and Umax, respectively, from the TASCC method. The CIs for Sw-amb and Umax were large, but were not consistently larger using the MC method. Despite the large CIs, significant differences (based on nonoverlapping CIs) in nutrient metrics among seasons were found with more significant differences using the OLS/NLS vs. the MC method. Lastly, we suggest that the MC approach is a robust way to estimate uncertainty, as the calculation of Sw-amb and Umax violates assumptions of OLS/NLS while the MC approach is free of these assumptions. The MC approach can be applied to other ecosystem metrics that are calculated from multiple parameters, providing a more robust estimate of these metrics and their associated uncertainties.

  20. Fractionated low doses of abdominal irradiation alters jejunal uptake of nutrients

    SciTech Connect

    Thomson, A.B.; Keelan, M.; Cheeseman, C.I.; Walker, K.

    1986-06-01

    Abdominal radiation is associated with changes in intestinal uptake of nutrients that begins within three days and persist for over 33 weeks. Clinically, fractionated doses of radiation (FDR) are used in an attempt to minimize the complications of this therapy, but the effects of fractionated doses of radiation on intestinal transport have not been defined. An in vitro technique was used to assess the jejunal and ileal uptake of varying concentrations of glucose and leucine, as well as the uptake of single concentrations of fatty acids and decanol in rats exposed 3, 7, and 14 days previously to a course of 200 cGy given on each of five consecutive days. FDR was associated with an increase in the uptake of decanol, and therefore a decrease in the effective resistance of the unstirred water layer. FDR had a variable effect on the uptake of glucose and leucine, with a decline in the value of the Michaelis constant (Km) and the passive permeability coefficient for glucose (Pd), whereas the Km for leucine was unchanged and the Pd for leucine was variably affected by FDR. The maximal transport rate (Jdm) for leucine progressively rose following FDR, whereas the Jdm for glucose initially rose, then fell. The uptake of galactose and medium chain-length fatty acids was unchanged by FDR, whereas the jejunal uptake of myristic acid rose, and the uptake of cholic acid declined, then returned to normal. FDR was associated with greater body weight gain and jejunal and ileal weight. The changes in nutrient uptake following FDR differed from the absorption changes occurring after a single dose of radiation. Thus, fractionated doses of abdominal radiation produce complex changes in the intestinal uptake of actively and passively transported nutrients, and these variable changes are influenced by the time following radiation exposure and by the solute studied.

  1. Biotechnology of nutrient uptake and assimilation in plants.

    PubMed

    López-Arredondo, Damar L; Leyva-González, Marco A; Alatorre-Cobos, Fulgencio; Herrera-Estrella, Luis

    2013-01-01

    Plants require a complex balance of mineral nutrients to reproduce successfully. Because the availability of many of these nutrients in the soil is compromised by several factors, such as soil pH, cation presence, and microbial activity, crop plants depend directly on nutrients applied as fertilizers to achieve high yields. However, the excessive use of fertilizers is a major environmental concern due to nutrient leaching that causes water eutrophication and promotes toxic algae blooms. This situation generates the urgent need for crop plants with increased nutrient use efficiency and better-designed fertilization schemes. The plant biology revolution triggered by the development of efficient gene transfer systems for plant cells together with the more recent development of next-generation DNA and RNA sequencing and other omics platforms have advanced considerably our understanding on the molecular basis of plant nutrition and how plants respond to nutritional stress. To date, genes encoding sensors, transcription factors, transporters, and metabolic enzymes have been identified as potential candidates to improve nutrient use efficiency. In addition, the study of other genetic resources, such as bacteria and fungi, allows the identification of alternative mechanisms of nutrient assimilation, which are potentially applicable in plants. Although significant progress in this respect has been achieved by conventional breeding, in this review we focus on the biotechnological approaches reported to date aimed at boosting the use of the three most limiting nutrients in the majority of arable lands: nitrogen, phosphorus, and iron.

  2. The relationship between light intensity and nutrient uptake kinetics in six freshwater diatoms.

    PubMed

    Shi, Pengling; Shen, Hong; Wang, Wenjing; Chen, Wenjie; Xie, Ping

    2015-08-01

    In order to find effective measures to control diatom blooms, a better understanding of the physiological characteristics of nutrient uptake in diatoms is needed. A study of P and Si-uptake kinetics for diatom species from two light regimes was conducted at low (LL), moderate (ML) and high light intensities (HL) (2, 25 and 80 μmol photons/(m(2)·sec)), respectively. The results showed that P uptake of diatoms was heavily influenced by historic light regimes. P affinity changed with growth and photosynthetic activity. The lowest half saturation constant for P uptake (Km(P)) was under HL for high-light adapted diatoms while the lowest half-saturation constant for low-light adapted diatoms was observed under LL. The Si half-saturation constant (Km(Si)) increased with increasing light intensities for pennate diatoms but decreased for centric diatoms. Diatom volumes were correlated with the maximum Si uptake rates (Vm(Si)) at HL and Km(Si) at ML and HL for six diatom species. Our results imply that when we assess the development of diatom blooms we should consider light intensity and cell volume in addition to ambient Si or P concentration. The relationship between light intensity and P-uptake suggests that we can find suitable methods to control diatom blooms on the basis of reducing phytoplankton activity of P-uptake and photosynthesis simultaneously.

  3. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake

    NASA Astrophysics Data System (ADS)

    Mallard, J. M.; McGlynn, B. L.; Covino, T. P.; Bergstrom, A.

    2012-12-01

    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with a distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role

  4. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake

    NASA Astrophysics Data System (ADS)

    Mallard, John; McGlynn, Brian; Covino, Tim

    2016-04-01

    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role of

  5. Toward a transport-based analysis of nutrient spiraling and uptake in streams

    USGS Publications Warehouse

    Runkel, Robert L.

    2007-01-01

    Nutrient addition experiments are designed to study the cycling of nutrients in stream ecosystems where hydrologic and nonhydrologic processes determine nutrient fate. Because of the importance of hydrologic processes in stream ecosystems, a conceptual model known as nutrient spiraling is frequently employed. A central part of the nutrient spiraling approach is the determination of uptake length (SW), the average distance traveled by dissolved nutrients in the water column before uptake. Although the nutrient spiraling concept has been an invaluable tool in stream ecology, the current practice of estimating uptake length from steady-state nutrient data using linear regression (called here the "SW approach") presents a number of limitations. These limitations are identified by comparing the exponential SW equation with analytical solutions of a stream solute transport model. This comparison indicates that (1) SW, is an aggregate measure of uptake that does not distinguish between main channel and storage zone processes, (2) SW, is an integrated measure of numerous hydrologie and nonhydrologic processes-this process integration may lead to difficulties in interpretation when comparing estimates of SW, and (3) estimates of uptake velocity and areal uptake rate (Vf and U) based on S W, are not independent of system hydrology. Given these findings, a transport-based approach to nutrient spiraling is presented for steady-state and time-series data sets. The transport-based approach for time-series data sets is suggested for future research on nutrient uptake as it provides a number of benefits, including the ability to (1) separately quantify main channel and storage zone uptake, (2) quantify specific hydrologic and nonhydrologic processes using various model parameters (process separation), (3) estimate uptake velocities and areal uptake rates that are independent of hydrologic effects, and (4) use short-term, non-plateau nutrient additions such that the effects of

  6. Nutrient uptake and mineralization during leaf decay in streams - a model simulation

    SciTech Connect

    Webster, Jackson; Newbold, J. Denis; Thomas, Steve; Valett, H. Maurice; Mulholland, Patrick J

    2009-01-01

    We developed a stoichiometrically explicit computer model to examine how heterotrophic uptake of nutrients and microbial mineralization occurring during the decay of leaves in streams may be important in modifying nutrient concentrations. The simulations showed that microbial uptake can substantially decrease stream nutrient concentrations during the initial phases of decomposition, while mineralization may produce increases in concentrations during later stages of decomposition. The simulations also showed that initial nutrient content of the leaves can affect the stream nutrient concentration dynamics and determine whether nitrogen or phosphorus is the limiting nutrient. Finally, the simulations suggest a net retention (uptake > mineralization) of nutrients in headwater streams, which is balanced by export of particulate organic nutrients to downstream reaches. Published studies support the conclusion that uptake can substantially change stream nutrient concentrations. On the other hand, there is little published evidence that mineralization also affects nutrient concentrations. Also, there is little information on direct microbial utilization of nutrients contained in the decaying leaves themselves. Our results suggest several directions for research that will improve our understanding of the complex relationship between leaf decay and nutrient dynamics in streams.

  7. One-time tillage of no-till: Effects on nutrients, mycorrhizae, and phosphorus uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stratification of nutrient availability, especially of P, that develops with continuous no-till (NT) can affect runoff nutrient concentration and possibly nutrient uptake. The effects of composted manure application and one-time tillage of NT on the distribution of soil chemical properties, root co...

  8. Uptake and utilization of nutrients by developing kernels of Zea mays L

    SciTech Connect

    Lyznik, L.A.

    1987-01-01

    The mechanisms involved in amino acid and sugar uptake by developing maize kernels were investigated. In the pedicel region of maize kernel, the site of nutrient unloading from phloem terminals, amino acids are accumulated in considerable amounts and undergo significant interconversion. A wide spectrum of enzymatic activities involved in the metabolism of amino acids is observed in these tissues. Subsequently, amino acids are taken up by the endosperm tissue in processes which require energy and the presence of carrier proteins. Conversely, no evidence was found that energy and carriers are involved in sugar uptake. This process of sugar uptake is not inhibited by metabolic inhibitors and shows nonsaturable kinetics, but the uptake is pH-dependent. L-glucose is taken up at a significantly reduced rate in comparison to D-glucose uptake. Based on analysis of radioactivity distribution among sugar fractions after incubations of kernels with radiolabeled D-glucose, it seems that sucrose is not efficiently resynthesized from D-glucose in the endosperm tissue. Thus, the proposed mechanism of sucrose transport involving sucrose hydrolysis in the pedicel region and subsequent resynthesis in endosperm cells may not be the main pathway. The evidence that transfer cells play an active role in D-glucose transport is presented.

  9. A novel nanoparticle approach for imaging nutrient uptake by soil bacteria

    NASA Astrophysics Data System (ADS)

    O'Brien, S. L.; Whiteside, M. D.; Sholto-Douglas, D.; Antonopoulos, D. A.; Boyanov, M.; Durall, D. M.; Jones, M. D.; Lai, B.; O'Loughlin, E. J.; Kemner, K. M.

    2014-12-01

    The metabolic activities of soil microbes are the primary drivers of biogeochemical processes controlling the terrestrial carbon cycle, nutrient availability to plants, contaminant remediation, water quality, and other ecosystem services. However, we have a limited understanding of microbial metabolic processes such as nutrient uptake rates, substrate preferences, or how microbes and microbial metabolism are distributed throughout their habitat. Here we use a novel imaging technique with quantum dots (QDs, engineered semiconductor nanoparticles that produce size or composition-dependent fluorescence) to measure bacterial uptake of substrates of varying complexity. Cultures of two organisms differing in cell wall structure — Bacillus subtilis and Pseudomonas fluorescens — were grown in one of four ecologically relevant experimental conditions: nitrogen (N) limitation, phosphorus (P) limitation, N and P limitation, or no nutrient limitation. The cultures were then exposed to QDs with and without organic nutrients attached. X-ray fluorescence imaging was performed at 2ID-D at the Advanced Photon Source (APS) to determine the elemental distributions within both planktonic and surface-adhered (i.e, biofilms) cells. Uptake of unconjugated QDs was neglibible, and QDs conjugated to organic substrates varied depending on growth conditions and substrate, suggesting that they are a useful indicator of bacterial ecology. Cellular uptake was similar for the two bacterial species (2212 ± 273 nanoparticles per cm3 of cell volume for B. subtilis and 1682 ± 264 for P. fluorescens). On average, QD assimilation was six times greater when N or P was limiting, and cells took up about twice as much phosphoserine compared to other substrates, likely because it was the only compound providing both N and P. These results showed that regardless of their cell wall structure, bacteria can selectively take up quantifiable levels of QDs based on substrate and environmental conditions. APS

  10. Effect of Nutrient/Carbon Supplements on Biological Phosphate and Nitrate Uptake by Protozoan Isolates

    NASA Astrophysics Data System (ADS)

    Akpor, O. B.; Momba, M. N. B.; Okonkwo, J.

    This study was aimed at investigating the effect of nine different nutrient/carbon supplements in mixed liquor on nutrient uptake ability of three wastewater protozoan isolates, which have previously been screened for phosphate and nitrate uptake efficiency. The results revealed that over 50% of phosphate was removed in the presence of sodium acetate, glucose or sucrose. Similarly, nitrate uptake of over 60% was observed in the presence of sodium acetate, sodium succinate, glucose or sucrose. These trends were common in all the isolates. Chemical Oxygen Demand (COD) removal in the mixed liquor was only found to be significantly removed in mixed liquors that were supplemented with glucose, sucrose or sodium succinate. In the presence of sodium acetate, COD was observed to increase. The findings of this investigation have revealed that nutrient uptake and COD removal by the test protozoan isolates may be dependent primarily on the initial nutrient supplement in mixed liquor.

  11. Late effects of abdominal radiation on intestinal uptake of nutrients

    SciTech Connect

    Thomson, A.B.; Cheeseman, C.I.; Walker, K.

    1986-09-01

    The late effects of variable doses of abdominal irradiation on in vitro jejunal uptake were examined. The uptake of glucose, galactose, cholic acid, medium-chain length fatty acids, and decanol was studied 6 and 33 weeks following 300, 600, or 900 cGy abdominal irradiation. The intestinal morphological characteristics were similar 6 and 33 weeks after radiation. The uptake of cholic acid was unaffected by abdominal irradiation, but for glucose, galactose, and four fatty acids the direction and magnitude of the changes in uptake were influenced by the dose of irradiation and by the interval following exposure. The greater uptake of decanol at 6 weeks but lower uptake of decanol at 33 weeks reflected changes in the resistance of the intestinal unstirred water layer. These absorption changes suggest that the intestine may not be capable of correcting the transport abnormalities arising from sublethal doses of abdominal irradiation.

  12. Uptake of Pharmaceuticals Influences Plant Development and Affects Nutrient and Hormone Homeostases.

    PubMed

    Carter, Laura J; Williams, Mike; Böttcher, Christine; Kookana, Rai S

    2015-10-20

    The detection of a range of active pharmaceutical ingredients (APIs) in the soil environment has led to a number of publications demonstrating uptake by crops, however very few studies have explored the potential for impacts on plant development as a result of API uptake. This study investigated the effect of carbamazepine and verapamil (0.005-10 mg/kg) on a range of plant responses in zucchini (Cucurbita pepo). Uptake increased in a dose-dependent manner, with maximum leaf concentrations of 821.9 and 2.2 mg/kg for carbamazepine and verapamil, respectively. Increased carbamazepine uptake by zucchini resulted in a decrease in above (<60%) and below (<30%) ground biomass compared to the controls (p < 0.05). At soil concentrations >4 mg/kg the mature leaves suffered from burnt edges and white spots as well as a reduction in photosynthetic pigments but no such effects were seen for verapamil. For both APIs, further investigations revealed significant differences in the concentrations of selected plant hormones (auxins, cytokinins, abscisic acid and jasmonates), and in the nutrient composition of the leaves in comparison to the controls (p < 0.05). This is some of the first research to demonstrate that the exposure of plants to APIs is likely to cause impacts on plant development with unknown implications.

  13. Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

    NASA Astrophysics Data System (ADS)

    Gebremikael, Mesfin T.; Steel, Hanne; Buchan, David; Bert, Wim; de Neve, Stefaan

    2016-09-01

    The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

  14. Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

    PubMed Central

    Gebremikael, Mesfin T.; Steel, Hanne; Buchan, David; Bert, Wim; De Neve, Stefaan

    2016-01-01

    The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota. PMID:27605154

  15. Nutrient uptake and distribution in young Pinot noir grapevines over two seasons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The seasonal timing of biomass and nutrient uptake and distribution among different vine organs was determined over two growing seasons in 4-year-old Pinot noir grapevines carrying their first full crop and grown in field microplots. Vines were fertilized in spring and the biomass and nutrient conte...

  16. Astrocytic Insulin Signaling Couples Brain Glucose Uptake with Nutrient Availability.

    PubMed

    García-Cáceres, Cristina; Quarta, Carmelo; Varela, Luis; Gao, Yuanqing; Gruber, Tim; Legutko, Beata; Jastroch, Martin; Johansson, Pia; Ninkovic, Jovica; Yi, Chun-Xia; Le Thuc, Ophelia; Szigeti-Buck, Klara; Cai, Weikang; Meyer, Carola W; Pfluger, Paul T; Fernandez, Ana M; Luquet, Serge; Woods, Stephen C; Torres-Alemán, Ignacio; Kahn, C Ronald; Götz, Magdalena; Horvath, Tamas L; Tschöp, Matthias H

    2016-08-11

    We report that astrocytic insulin signaling co-regulates hypothalamic glucose sensing and systemic glucose metabolism. Postnatal ablation of insulin receptors (IRs) in glial fibrillary acidic protein (GFAP)-expressing cells affects hypothalamic astrocyte morphology, mitochondrial function, and circuit connectivity. Accordingly, astrocytic IR ablation reduces glucose-induced activation of hypothalamic pro-opio-melanocortin (POMC) neurons and impairs physiological responses to changes in glucose availability. Hypothalamus-specific knockout of astrocytic IRs, as well as postnatal ablation by targeting glutamate aspartate transporter (GLAST)-expressing cells, replicates such alterations. A normal response to altering directly CNS glucose levels in mice lacking astrocytic IRs indicates a role in glucose transport across the blood-brain barrier (BBB). This was confirmed in vivo in GFAP-IR KO mice by using positron emission tomography and glucose monitoring in cerebral spinal fluid. We conclude that insulin signaling in hypothalamic astrocytes co-controls CNS glucose sensing and systemic glucose metabolism via regulation of glucose uptake across the BBB.

  17. NPKS uptake, sensing, and signaling and miRNAs in plant nutrient stress.

    PubMed

    Nath, Manoj; Tuteja, Narendra

    2016-05-01

    Sessile nature of higher plants consequently makes it highly adaptable for nutrient absorption and acquisition from soil. Plants require 17 essential elements for their growth and development which include 14 minerals (macronutrients: N, P, K, Mg, Ca, S; micronutrients: Cl, Fe, B, Mn, Zn, Cu, Ni, Mo) and 3 non-mineral (C, H, O) elements. The roots of higher plants must acquire these macronutrients and micronutrients from rhizosphere and further allocate to other plant parts for completing their life cycle. Plants evolved an intricate series of signaling and sensing cascades to maintain nutrient homeostasis and to cope with nutrient stress/availability. The specific receptors for nutrients in root, root system architecture, and internal signaling pathways help to develop plasticity in response to the nutrient starvation. Nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) are essential for various metabolic processes, and their deficiency negatively effects the plant growth and yield. Genes coding for transporters and receptors for nutrients as well as some small non-coding RNAs have been implicated in nutrient uptake and signaling. This review summarizes the N, P, K, and S uptake, sensing and signaling events in nutrient stress condition especially in model plant Arabidopsis thaliana and involvement of microRNAs in nutrient deficiency. This article also provides a framework of uptake, sensing, signaling and to highlight the microRNA as an emerging major players in nutrient stress condition. Nutrient-plant-miRNA cross talk may help plant to cope up nutrient stress, and understanding their precise mechanism(s) will be necessary to develop high yielding smart crop with low nutrient input.

  18. A H+-ATPase That Energizes Nutrient Uptake during Mycorrhizal Symbioses in Rice and Medicago truncatula[C][W][OPEN

    PubMed Central

    Wang, Ertao; Yu, Nan; Bano, S. Asma; Liu, Chengwu; Miller, Anthony J.; Cousins, Donna; Zhang, Xiaowei; Ratet, Pascal; Tadege, Million; Mysore, Kirankumar S.; Downie, J. Allan; Murray, Jeremy D.; Oldroyd, Giles E.D.; Schultze, Michael

    2014-01-01

    Most plant species form symbioses with arbuscular mycorrhizal (AM) fungi, which facilitate the uptake of mineral nutrients such as phosphate from the soil. Several transporters, particularly proton-coupled phosphate transporters, have been identified on both the plant and fungal membranes and contribute to delivering phosphate from fungi to plants. The mechanism of nutrient exchange has been studied in plants during mycorrhizal colonization, but the source of the electrochemical proton gradient that drives nutrient exchange is not known. Here, we show that plasma membrane H+-ATPases that are specifically induced in arbuscule-containing cells are required for enhanced proton pumping activity in membrane vesicles from AM-colonized roots of rice (Oryza sativa) and Medicago truncatula. Mutation of the H+-ATPases reduced arbuscule size and impaired nutrient uptake by the host plant through the mycorrhizal symbiosis. Overexpression of the H+-ATPase Os-HA1 increased both phosphate uptake and the plasma membrane potential, suggesting that this H+-ATPase plays a key role in energizing the periarbuscular membrane, thereby facilitating nutrient exchange in arbusculated plant cells. PMID:24781115

  19. Cation uptake and allocation by red pine seedlings under cation-nutrient stress in a column growth experiment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background and aims: Plant nutrient uptake is affected by environmental stress, but how plants respond to cation nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient stress on cation uptake in an experimental plant-mineral system. Methods: Column experim...

  20. Discontinuities in stream nutrient uptake below lakes in mountain drainage networks

    USGS Publications Warehouse

    Arp, C.D.; Baker, M.A.

    2007-01-01

    In many watersheds, lakes and streams are hydrologically linked in spatial patterns that influence material transport and retention. We hypothesized that lakes affect stream nutrient cycling via modifications to stream hydrogeomorphology, source-waters, and biological communities. We tested this hypothesis in a lake district of the Sawtooth Mountains, Idaho. Uptake of NO3- and PO4-3 was compared among 25 reaches representing the following landscape positions: lake inlets and outlets, reaches >1-km downstream from lakes, and reference reaches with no nearby lakes. We quantified landscape-scale hydrographic and reach-scale hydrogeomorphic, source-water, and biological variables to characterize these landscape positions and analyze relationships to nutrient uptake. Nitrate uptake was undetectable at most lake outlets, whereas PO4-3 uptake was higher at outlets as compared to reference and lake inlet reaches. Patterns in nutrient demand farther downstream were similar to lake outlets with a gradual shift toward reference-reach functionality. Nitrate uptake was most correlated to sediment mobility and channel morphology, whereas PO 4-3 uptake was most correlated to source-water characteristics. The best integrated predictor of these patterns in nutrient demand was % contributing area (the proportion of watershed area not routing through a lake). We estimate that NO3- and PO 4-3 demand returned to 50% of pre-lake conditions within 1-4-km downstream of a small headwater lake and resetting of nutrient demand was slower downstream of a larger lake set lower in a watershed. Full resetting of these nutrient cycling processes was not reached within 20-km downstream, indicating that lakes can alter stream ecosystem functioning at large spatial scales throughout mountain watersheds. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

  1. Nitrate uptake varies with tide height and nutrient availability in the intertidal seaweed Fucus vesiculosus.

    PubMed

    Benes, Kylla M; Bracken, Matthew E S

    2016-10-01

    Intertidal seaweeds must cope with a suite of stressors imposed by aerial exposure at low tide, including nutrient limitation due to emersion. Seaweeds can access nutrients only when submerged, so individuals living higher compared to lower on the shore may have adaptations allowing them to acquire sufficient amounts of nutrients to survive and maintain growth. Using a combination of observations and experiments, we aimed to identify intraspecific variation in nitrate uptake rates across the intertidal distribution of F. vesiculosus, as well as test for acclimation in response to a change in tide height. We replicated our study at sites spanning nearly the entire Gulf of Maine coastline, to examine how local environmental variability may alter intraspecific variation in nitrate uptake. We found that average nitrate uptake rates were ~18% higher in upper compared to lower intertidal Fucus vesiculosus. Furthermore, we found evidence for both acclimation and adaptation to tide height during a transplant experiment. F. vesiculosus transplanted from the lower to the upper intertidal zone was characterized by increased nitrate uptake, but individuals transplanted from the upper to the lower intertidal zone retained high uptake rates. Our observations differed among Gulf of Maine regions and among time points of our study. Importantly, these differences may reflect associations between nitrate uptake rates and abiotic environmental conditions and seaweed nutrient status. Our study highlights the importance of long-term variation in ambient nutrient supply in driving intraspecific variation of seaweeds across the intertidal gradient and local and seasonal variation in ambient nutrient levels in mediating intraspecific differences.

  2. Dissolved inorganic carbon enhanced growth, nutrient uptake, and lipid accumulation in wastewater grown microalgal biofilms.

    PubMed

    Kesaano, Maureen; Gardner, Robert D; Moll, Karen; Lauchnor, Ellen; Gerlach, Robin; Peyton, Brent M; Sims, Ronald C

    2015-03-01

    Microalgal biofilms grown to evaluate potential nutrient removal options for wastewaters and feedstock for biofuels production were studied to determine the influence of bicarbonate amendment on their growth, nutrient uptake capacity, and lipid accumulation after nitrogen starvation. No significant differences in growth rates, nutrient removal, or lipid accumulation were observed in the algal biofilms with or without bicarbonate amendment. The biofilms possibly did not experience carbon-limited conditions because of the large reservoir of dissolved inorganic carbon in the medium. However, an increase in photosynthetic rates was observed in algal biofilms amended with bicarbonate. The influence of bicarbonate on photosynthetic and respiration rates was especially noticeable in biofilms that experienced nitrogen stress. Medium nitrogen depletion was not a suitable stimulant for lipid production in the algal biofilms and as such, focus should be directed toward optimizing growth and biomass productivities to compensate for the low lipid yields and increase nutrient uptake.

  3. Sudden increase in atmospheric CO2 concentration reveals strong coupling between shoot carbon uptake and root nutrient uptake in young walnut trees.

    PubMed

    Delaire, Mickaël; Frak, Ela; Sigogne, Monique; Adam, Boris; Beaujard, François; Le Roux, Xavier

    2005-02-01

    We studied the short-term (i.e., a few days) effect of a sudden increase in CO2 uptake by shoots on nutrient (NO3-, P ion, K+, Ca2+ and Mg2+) uptake by roots during vegetative growth of young walnut (Juglans nigra x J. major L.) trees. The increase in CO2 uptake was induced by a sudden increase in atmospheric CO2 concentration ([CO2]). Twelve 2-year-old trees were transplanted and grown in perlite-filled pots in a greenhouse. Rates of CO2 uptake and water loss by individual trees were determined by a branch bag method from 3 days before until 6 days after [CO2] was increased. Nutrient uptake rates were measured concurrently by a hydroponic recirculating nutrient solution system that provided non-limiting supplies of water and nutrients. Six control trees were kept in ambient [CO2] (360 ppm), and [CO2] was increased to 550 ppm for one set of three trees and to 800 ppm for another set of three trees. Before imposing the elevated [CO2] treatments, all trees exhibited similar daily water loss, CO2 uptake and nutrient uptake rates when expressed per unit leaf area to account for the tree size effect. Daily water loss rates were only slightly affected by elevated [CO2]. Carbon dioxide uptake rates greatly increased with increasing atmospheric [CO2], and nutrient uptake rates were proportional to CO2 uptake rates during the study period, except for P ion. Our results show that, despite the important carbon and nitrogen storage capacities previously observed in young walnut trees, nutrient uptake by roots is strongly coupled to carbon uptake by shoots over periods of a few days.

  4. Effects of light intensity and temperature on Cryptomonas ovata (Cryptophyceae) growth and nutrient uptake rates

    USGS Publications Warehouse

    Cloern, James E.

    1977-01-01

    Specific growth rate of Cryptomonas ovata var. palustris Pringsheim was measured in batch culture at 14 light-temperature combinations. Both the maximum growth rate (μm) and optimum light intensity (Iopt) fit an empirical function that increases exponentially with temperature up to an optimum (Topt), then declines rapidly as temperature exceeds Topt. Incorporation of these functions into Steele's growth equation gives a good estimate of specific growth rate over a wide range of temperature and light intensity. Rates of phosphate, ammonium and nitrate uptake were measured separately at 16 combinations of irradiance and temperature and following a spike addition of all starved cells initially took up nutrient at a rapid rate. This transitory surge was followed by a period of steady, substrate-saturated uptake that persisted until external nutrient concentration fell. Substrate-saturated NO3−-uptake proceeded at very slow rates in the dark and was stimulated by both increased temperature and irradiance; NH4+-uptake apparently proceeded at a basal rate at 8 and l4 C and was also stimulated by increased temperature and irradiance. Rates of NH4−-uptake were much higher than NO3−-uptake at all light-temperature combinations. Below 20 C, PO4−3-uptake was more rapid in dark than in light, but was light enhanced at 26 C.

  5. Seasonal Growth and Uptake of Nutrients by Orchardgrass Irrigated with Wastewater,

    DTIC Science & Technology

    1981-05-01

    501Herron, G.M., D.W. Grimes and I.T. Musick (1963) Effects of to 35 to 40 days during the second harvest soil moisture and nitrogen fertilization of...facsimile catalog card in Library of Congress MARC format is reproduced below. Palazzo, A.J. Seasonal growth and uptake of nutrients by orchardgrass irrigated

  6. Nutrient uptake and loss by container-grown deciduous and evergreen Rhododendron nursery plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of N fertilizer application on plant uptake and demand for other nutrients was evaluated from May 2005 to February 2006 in container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ). Increased N-availability incre...

  7. Nutrient uptake, biomass yield and quantitative analysis of aliphatic aldehydes in cilantro plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate the nutrient uptake, biomass production and yield of the major compounds in the essential oil of five genotypes of Coriandrum sativum L. The treatments were four accessions donated by the National Genetic Resources Advisory Council (NGRAC), U.S. Department...

  8. Impact of FGD gypsum on soil fertility and plant nutrient uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of FGD gypsum is thought to improve soil productivity and increase plant production. Thus, a study was conducted to evaluate the effects of FGD gypsum on yield, plant nutrient uptake and soil productivity. The study was conducted on an established bermudagrass pasture. Poultry litter was applied...

  9. Predictive modeling of transient storage and nutrient uptake: Implications for stream restoration

    USGS Publications Warehouse

    O'Connor, Ben L.; Hondzo, Miki; Harvey, Judson

    2010-01-01

    This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting methods. Nitrate (NO3–) uptake rates inferred using the nutrient spiraling model underestimated the total NO3– mass loss by 82%, which was attributed to the exclusion of dispersion and transient storage. The transient storage model was more accurate with respect to the NO3– mass loss (±20%) and also demonstrated that uptake in the main channel was more significant than in storage zones. Conservative tracer fitting was unable to produce transport parameter estimates for a riffle-pool transition of the study reach, while forward modeling of solute transport using measured/scaled transport parameters matched conservative tracer breakthrough curves for all reaches. Additionally, solute exchange between the main channel and embayment surface storage zones was quantified using first-order theory. These results demonstrate that it is vital to account for transient storage in quantifying nutrient uptake, and the continued development of measurement/scaling techniques is needed for reactive transport modeling of streams with complex hydraulic and geomorphic conditions.

  10. Low transient storage and uptake efficiencies in seven agricultural streams: implications for nutrient demand

    USGS Publications Warehouse

    Sheibley, Rich W.; Duff, John H.; Tesoriero, Anthony J.

    2014-01-01

    We used mass load budgets, transient storage modeling, and nutrient spiraling metrics to characterize nitrate (NO3−), ammonium (NH4+), and inorganic phosphorus (SRP) demand in seven agricultural streams across the United States and to identify in-stream services that may control these conditions. Retention of one or all nutrients was observed in all but one stream, but demand for all nutrients was low relative to the mass in transport. Transient storage metrics (As/A, Fmed200, Tstr, and qs) correlated with NO3− retention but not NH4+ or SRP retention, suggesting in-stream services associated with transient storage and stream water residence time could influence reach-scale NO3− demand. However, because the fraction of median reach-scale travel time due to transient storage (Fmed200) was ≤1.2% across the sites, only a relatively small demand for NO3− could be generated by transient storage. In contrast, net uptake of nutrients from the water column calculated from nutrient spiraling metrics were not significant at any site because uptake lengths calculated from background nutrient concentrations were statistically insignificant and therefore much longer than the study reaches. These results suggest that low transient storage coupled with high surface water NO3− inputs have resulted in uptake efficiencies that are not sufficient to offset groundwater inputs of N. Nutrient retention has been linked to physical and hydrogeologic elements that drive flow through transient storage areas where residence time and biotic contact are maximized; however, our findings indicate that similar mechanisms are unable to generate a significant nutrient demand in these streams relative to the loads.

  11. Interactive effects of phosphorus and Pseudomonas putida on chickpea (Cicer arietinum L.) growth, nutrient uptake, antioxidant enzymes and organic acids exudation.

    PubMed

    Israr, Dania; Mustafa, Ghulam; Khan, Khalid Saifullah; Shahzad, Muhammad; Ahmad, Niaz; Masood, Sajid

    2016-11-01

    Phosphorus (P) availability in alkaline soils of arid and semi-arid regions is a major constraint for decreased crop productivity. Use of plant growth promoting rhizobacteria (PGPR) may enhance plant growth through the increased plant antioxidation activity. Additionally, PGPR may increase nutrient uptake by plants as a result of induced root exudation and rhizosphere acidification. The current study was aimed to investigate combined effects of P and Pesudomonas putida (PGPR) on chickpea growth with reference to antioxidative enzymatic activity and root exudation mediated plant nutrient uptake, particularly P. Half of the seeds were soaked in PGPR solution, whereas others in sterile water and latter sown in soils. Plants were harvested 8 weeks after onset of experiment and analyzed for leaf nutrient contents, antioxidant enzymes activities and organic acids concentrations. Without PGPR, P application (+P) increased various plant growth attributes, plant uptake of P and Ca, soil pH, citric acid and oxalic acid concentrations, whereas decreased the leaf POD enzymatic activity as compared to the P-deficiency. PGPR supply both under -P and +P improved the plant growth, plant uptake of N, P, and K, antioxidative activity of SOD and POD enzymes and concentrations of organic acids, whereas reduced the rhizosphere soil pH. Growth enhancement by PGPR supply was related to higher plant antioxidation activity as well as nutrient uptake of chickpea including P as a result of root exudation mediated rhizosphere acidification.

  12. Heat Stress Decreases Levels of Nutrient-Uptake and -Assimilation Proteins in Tomato Roots

    PubMed Central

    Giri, Anju; Heckathorn, Scott; Mishra, Sasmita; Krause, Charles

    2017-01-01

    Global warming will increase root heat stress, which is already common under certain conditions. Effects of heat stress on root nutrient uptake have rarely been examined in intact plants, but the limited results indicate that heat stress will decrease it; no studies have examined heat-stress effects on the concentration of nutrient-uptake proteins. We grew Solanum lycopersicum (tomato) at 25 °C/20 °C (day/night) and then transferred some plants for six days to 35 °C /30 °C (moderate heat) or 42 °C/37 °C (severe heat) (maximum root temperature = 32 °C or 39 °C, respectively); plants were then moved back to control conditions for seven days to monitor recovery. In a second experiment, plants were grown for 15 days at 28 °C/23 °C, 32 °C/27 °C, 36 °C/31 °C, and 40 °C/35 °C (day/night). Concentrations of nutrient-uptake and -assimilation proteins in roots were determined using protein-specific antibodies and ELISA (enzyme-linked immunosorbent assay). In general, (1) roots were affected by heat more than shoots, as indicated by decreased root:shoot mass ratio, shoot vs. root %N and C, and the level of nutrient metabolism proteins vs. less sensitive photosynthesis and stomatal conductance; and (2) negative effects on roots were large and slow-to-recover only with severe heat stress (40 °C–42 °C). Thus, short-term heat stress, if severe, can decrease total protein concentration and levels of nutrient-uptake and -assimilation proteins in roots. Hence, increases in heat stress with global warming may decrease crop production, as well as nutritional quality, partly via effects on root nutrient relations. PMID:28106834

  13. Staining with 0.05% neutral red reduces nutrient uptake by wheat roots.

    PubMed

    Trolove, Stephen; Tan, Yong; Reid, Jeff

    2015-11-01

    A number of studies have used a 0.05% solution of neutral red to stain live roots so that short term root growth could be measured. These studies, which used a 5 or 10 min staining time, report no effects of the stain on plant properties such as growth, respiration, or nitrate uptake. This paper reports on two experiments conducted to determine whether this staining technique, with a 15 min stain time, affected macronutrient uptake of 6- and 7-week-old wheat (Triticum aestivum L.) plants grown in solution culture. The results showed that, compared with unstained controls, staining plants with 0.05% neutral red halted or halved nitrate uptake measured over a 4 h period the following day. Potassium uptake was also significantly reduced by staining. In the experiment with smaller plants nutrient uptake rate recovered 5 days after staining, but not in the second experiment with larger plants. Stained roots were 19% narrower than unstained roots, suggesting that the stain affected the root structure. We do not recommend the use of 0.05% neutral red staining, for wheat at least, in experiments where accurate measurement of nutrient uptake rate is important.

  14. 2-D clinorotation alters the uptake of some nutrients in Arabidopsis thaliana.

    PubMed

    Polinski, Ellen; Schueler, Oliver; Krause, Lars; Wimmer, Monika A; Hemmersbach, Ruth; Goldbach, Heiner E

    2017-02-16

    Future long-term spaceflight missions rely on bioregenerative life support systems (BLSS) in order to provide the required resources for crew survival. Higher plants provide an essential part since they supply food and oxygen and recycle carbon dioxide. There are indications that under space conditions plants might be inefficient regarding the uptake, transport and distribution of nutrients, which in turn affects growth and metabolism. Therefore, Arabidopsis thaliana (Col-0) seeds were germinated and grown for five days under fast clinorotation (2-D clinostat, 60rpm) in order to simulate microgravity. Concentrations of ten different nutrients (potassium, sulfur, phosphorus, calcium, sodium, magnesium, manganese, iron, zinc, and boron) in shoots of plants grown under reduced and normal (1g) gravity conditions were compared. A protocol was developed for the determination of different nutrients by means of inductively coupled plasma optical emission spectrometry (ICPOES), flame emission spectrometry and spectrophotometry. The concentrations of boron and sulfur were significantly decreased in clinorotated shoots, while the concentration of sodium was elevated, suggesting that altered gravity conditions differentially affected nutrient uptake. Possible mechanisms for such effects include reduced transpiration, altered expression of channels or transporters and direct effects on nutrient assimilation. The observed nutrient imbalances might have a negative impact on plant growth and nutritional quality during prolonged space missions.

  15. Mycorrhiza and heavy metal resistant bacteria enhance growth, nutrient uptake and alter metabolic profile of sorghum grown in marginal soil.

    PubMed

    Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika

    2016-08-01

    The main challenge for plants growing in nutrient poor, contaminated soil is biomass reduction, nutrient deficiency and presence of heavy metals. Our aim is to overcome these challenges using different microbial combinations in mining-impacted soil and focus on their physiological and biochemical impacts on a model plant system, which has multiple applications. In the current study, sorghum BTx623 seedlings grown in mining-impacted soil in greenhouse were subjected to plant growth promoting bacteria (PGPB or B) alone, PGPB with arbuscular mycorrhizal fungi (My), My alone and control group with no treatment. Root biomass and uptake of most of the elements showed significant increase in all treatment groups in comparison with control. Mycorrhiza group showed the best effect followed by My + B and B groups for uptake of majority of the elements by roots. On the contrary, biomass of both shoot and root was more influenced by B treatment than My + B and My treatments. Metabolomics identified compounds whose levels changed in roots of treatment groups significantly in comparison to control. Upregulation of stearic acid, sorbitol, sebacic acid and ferulic acid correlated positively with biomass and uptake of almost all elements. Two biochemical pathways, fatty acid biosynthesis and galactose metabolism, were regulated in all treatment groups. Three common pathways were upregulated only in My and My + B groups. Our results suggest that PGPB enhanced metabolic activities which resulted in increase in element uptake and sorghum root biomass whether accompanied with mycorrhiza or used solely.

  16. Scaling plant nitrogen use and uptake efficiencies in response to nutrient addition in peatlands

    SciTech Connect

    Iversen, Colleen M; Bridgham, Scott; Kellogg, Laurie E.

    2010-01-01

    Nitrogen (N) is the primary growth-limiting nutrient in many terrestrial ecosystems, and therefore plant production per unit N taken up (i.e., N use efficiency, NUE) is a fundamentally important component of ecosystem function. Nitrogen use efficiency comprises two components: N productivity (AN, plant production per peak biomass N content) and the mean residence time of N in plant biomass (MRTN). We utilized a five-year fertilization experiment to examine the manner in which increases in N and phosphorus (P) availability affected plant NUE at multiple biological scales (i.e., from leaf to community level). We fertilized a natural gradient of nutrient-limited peatland ecosystems in the Upper Peninsula of Michigan, USA, with 6 g Nm2yr1, 2 g Pm2yr1, or a combination of N and P. Our objectives were to determine how changes in carbon and N allocation within a plant to leaf and woody tissue and changes in species composition within a community, both above- and belowground, would affect (1) NUE; (2) the adaptive trade-off between the components of NUE; (3) the efficiency with which plants acquired N from the soil (N uptake efficiency); and (4) plant community production per unit soil N availability (N response efficiency, NRE). As expected, N and P addition generally increased aboveground production and N uptake. In particular, P availability strongly affected the way in which plants took up and used N. Nitrogen use efficiency response to nutrient addition was not straightforward. Nitrogen use efficiency differed between leaf and woody tissue, among species, and across the ombrotrophic minerotrophic gradient because plants and communities were adapted to maximize either AN or MRTN, but not both concurrently. Increased N availability strongly decreased plant and community N uptake efficiency, while increased P availability increased N uptake efficiency, particularly in a nitrogen-fixing shrub. Nitrogen uptake efficiency was more important in controlling overall plant

  17. Scaling plant nitrogen use and uptake efficiencies in response to nutrient addition in peatlands.

    PubMed

    Iversen, Colleen M; Bridgham, Scott D; Kellogg, Laurie E

    2010-03-01

    Nitrogen (N) is the primary growth-limiting nutrient in many terrestrial ecosystems, and therefore plant production per unit N taken up (i.e., N use efficiency, NUE) is a fundamentally important component of ecosystem function. Nitrogen use efficiency comprises two components: N productivity (A(N), plant production per peak biomass N content) and the mean residence time of N in plant biomass (MRT(N)). We utilized a five-year fertilization experiment to examine the manner in which increases in N and phosphorus (P) availability affected plant NUE at multiple biological scales (i.e., from leaf to community level). We fertilized a natural gradient of nutrient-limited peatland ecosystems in the Upper Peninsula of Michigan, USA, with 6 g N x m(-2) x yr(-1), 2 g P x m(-2) x yr(-1), or a combination of N and P. Our objectives were to determine how changes in carbon and N allocation within a plant to leaf and woody tissue and changes in species composition within a community, both above- and belowground, would affect (1) NUE; (2) the adaptive trade-off between the components of NUE; (3) the efficiency with which plants acquired N from the soil (N uptake efficiency); and (4) plant community production per unit soil N availability (N response efficiency, NRE). As expected, N and P addition generally increased aboveground production and N uptake. In particular, P availability strongly affected the way in which plants took up and used N. Nitrogen use efficiency response to nutrient addition was not straightforward. Nitrogen use efficiency differed between leaf and woody tissue, among species, and across the ombrotrophic-minerotrophic gradient because plants and communities were adapted to maximize either A(N) or MRT(N), but not both concurrently. Increased N availability strongly decreased plant and community N uptake efficiency, while increased P availability increased N uptake efficiency, particularly in a nitrogen-fixing shrub. Nitrogen uptake efficiency was more important

  18. Antimony uptake by Zea mays (L.) and Helianthus annuus (L.) from nutrient solution.

    PubMed

    Tschan, Martin; Robinson, Brett; Schulin, Rainer

    2008-04-01

    We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans.

  19. Plant growth-promoting rhizobacteria affect the growth and nutrient uptake of Fraxinus americana container seedlings.

    PubMed

    Liu, Fangchun; Xing, Shangjun; Ma, Hailin; Du, Zhenyu; Ma, Bingyao

    2013-05-01

    Plant growth-promoting rhizobacteria (PGPR) are important catalysts that regulate the functional properties of agricultural systems. However, there is little information on the effect of PGPR inoculation on the growth and nutrient accumulation of forest container seedlings. This study determined the effects of a growth medium inoculated with PGPR on the nutrient uptake, nutrient accumulation, and growth of Fraxinus americana container seedlings. PGPR inoculation with fertilizer increased the dry matter accumulation of the F. americana aerial parts with delayed seedling emergence time. Under fertilized conditions, the accumulation time of phosphorous (P) and potassium (K) in the F. americana aerial parts was 13 days longer due to PGPR inoculation. PGPR increased the maximum daily P and K accumulations in fertilized seedlings by 9.31 and 10.44 %, respectively, but had little impact on unfertilized ones. Regardless of fertilizer application, the root exudates, namely sugars, amino acids, and organic acids significantly increased because of PGPR inoculation. PGPR inoculation with fertilizer increased the root, shoot, and leaf yields by 19.65, 22.94, and 19.44 %, respectively, as well as the P and K contents by 8.33 and 10.60 %, respectively. Consequently, the N, P, and K uptakes increased by 19.85, 31.97, and 33.95 %, respectively. Hence, PGPR inoculation with fertilizer can be used as a bioenhancer for plant growth and nutrient uptake in forest container seedling nurseries.

  20. The Role of Diatom Nanostructures in Biasing Diffusion to Improve Uptake in a Patchy Nutrient Environment

    PubMed Central

    Mitchell, James G.; Seuront, Laurent; Doubell, Mark J.; Losic, Dusan; Voelcker, Nicolas H.; Seymour, Justin; Lal, Ratnesh

    2013-01-01

    Background Diatoms are important single-celled autotrophs that dominate most lit aquatic environments and are distinguished by surficial frustules with intricate designs of unknown function. Principal Findings We show that some frustule designs constrain diffusion to positively alter nutrient uptake. In nutrient gradients of 4 to 160 times over <5 cm, the screened-chambered morphology of Coscincodiscus sp. biases the nutrient diffusion towards the cell by at least 3.8 times the diffusion to the seawater. In contrast, the open-chambers of Thalassiosira eccentrica produce at least a 1.3 times diffusion advantage to the membrane over Coscincodiscus sp. when nutrients are homogeneous. Significance Diffusion constraint explains the success of particular diatom species at given times and the overall success of diatoms. The results help answer the unresolved question of how adjacent microplankton compete. Furthermore, diffusion constraint by supramembrane nanostructures to alter molecular diffusion suggests that microbes compete via supramembrane topology, a competitive mechanism not considered by the standard smooth-surface equations used for nutrient uptake nor in microbial ecology and cell physiology. PMID:23667421

  1. Long-term effects of sustained beef feedlot manure application on soil nutrients, corn silage yield, and nutrient uptake.

    PubMed

    Ferguson, Richard B; Nienaber, John A; Eigenberg, Roger A; Woodbury, Brian L

    2005-01-01

    A field study was initiated in 1992 to investigate the long-term impacts of beef feedlot manure application (composted and uncomposted) on nutrient accumulation and movement in soil, corn silage yield, and nutrient uptake. Two application strategies were compared: providing the annual crop nitrogen (N) requirement (N-based rate) or crop phosphorus (P) removal (P-based rate), as well as a comparison to inorganic fertilizer. Additionally, effects of a winter cover crop were evaluated. Irrigated corn (Zea mays L.) was produced annually from 1993 through 2002. Average silage yield and crop nutrient removal were highest with N-based manure treatments, intermediate with P-based manure treatments, and least with inorganic N fertilizer. Use of a winter cover crop resulted in silage yield reductions in four of ten years, most likely due to soil moisture depletion in the spring by the cover crop. However, the cover crop did significantly reduce NO3-N accumulation in the shallow vadose zone, particularly in latter years of the study. The composted manure N-based treatment resulted in significantly greater soil profile NO3-N concentration and higher soil P concentration near the soil surface. The accounting procedure used to calculate N-based treatment application rates resulted in acceptable soil profile NO3-N concentrations over the short term. While repeated annual manure application to supply the total crop N requirement may be acceptable for this soil for several years, sustained application over many years carries the risk of unacceptable soil P concentrations.

  2. Ingestion of crude oil: effects on digesta retention times and nutrient uptake in captive river otters.

    PubMed

    Ormseth, O A; Ben-David, M

    2000-09-01

    Studies following the Exxon Valdez oil spill in Prince William Sound, Alaska indicated that river otters (Lontra canadensis) from oiled regions displayed symptoms of degraded health, including reduced body weight. We examined the fate of ingested oil in the digestive tract and its effects on gut function in captive river otters. Fifteen wild-caught males were assigned to three groups, two of which were given weathered crude oil in food (i.e., control, 5 ppm day(-1), and 50 ppm day(-1)) under controlled conditions at the Alaska Sealife Center. Using glass beads as non-specific digesta markers and stable isotope analysis, we determined the effects of ingested oil on retention time and nutrient uptake. Our data indicated that oil ingestion reduced marker retention time when we controlled for activity and meal size. Fecal isotope ratios suggested that absorption of lipids in the oiled otters might have been affected by reduced retention time of food. In addition, a dilution model indicated that as much as 80% of ingested oil was not absorbed in high-dose animals. Thus, while the ingestion of large quantities of weathered crude oil appears to reduce absorption of oil hydrocarbons and may alleviate systemic effects, it may concurrently affect body condition by impacting digestive function.

  3. Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances

    PubMed Central

    Palanivell, Perumal; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad; Jalloh, Mohamadu Boyie; Susilawati, Kasim

    2015-01-01

    High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot−1). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot−1) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot−1) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials. PMID:25977938

  4. Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances.

    PubMed

    Palanivell, Perumal; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad; Jalloh, Mohamadu Boyie; Susilawati, Kasim

    2015-01-01

    High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot(-1)). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot(-1)) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot(-1)) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials.

  5. 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

  6. Intestinal nutrient uptake measurements and tissue damage: validating the everted sleeves method.

    PubMed

    Starck, J M; Karasov, W H; Afik, D

    2000-01-01

    The reliability of methods for nutrient uptake measurements across the intestinal epithelium relies on the integrity of the mucosal epithelium and the enterocytes. We tested effects of tissue handling during the "everted sleeves method" on the length of intestinal villi, the surface magnification, the circumference of the gut, and the thickness of the muscle layer in sunbirds (Nectarinia osea), chicken (Gallus gallus), and mice (Mus domesticus). The sunbird has thin and delicate intestinal villi that are greatly affected by the everted sleeves method. After eversion and incubation, villi lost 30% of their original length. The severe tissue damage coincides with uptake measurements for glucose that were an order of magnitude lower than in other nectar-feeding (nectarivorous) birds of similar body size. Tissue handling during the everted sleeves method had significant effects on morphometric parameters of chicken and mouse intestines, but on a light-microscopical level, the tissue integrity and the cytology of the enterocytes were not altered. Therefore, we think that the everted sleeves method renders reliable and reproducible measurements of nutrient uptake in those species. We conclude that a histological evaluation is necessary to assess the reliability of the method before it is applied to adults or to the developmental stage of any species.

  7. Influence of sodium selenite on growth, nutrient utilization and selenium uptake in Cavia porcellus.

    PubMed

    Mahima; Garg, A K; Mudgal, Vishal

    2012-05-01

    A 70 day experiment on forty guinea pigs (Cavia porcellus) was conducted to find the influence of different level of sodium selenite (inorganic selenium supplementation) on growth, nutrient utilization and selenium uptake. The sodium selenite was supplemented into a basal diet at 0, 0.1, 0.2 and 0.3 ppm, respectively and the basal diet comprised of 25% ground cowpea (Vigna unguiculata) hay, 30% ground maize (Zea mays) grain, 22% ground gram (Cicer arietinum) grain, 9.5% deoiled rice (Oryza sativa) bran, 6% soybean (Glycine max) meal, 6% fish meal, 1.5% mineral mixture (without Se), ascorbic acid (200 mg kg) and 0.1 ppm Se to meet their nutrient requirements. Daily feed intake and weekly body weights were recorded. Intake and digestibility of dry matter, organic matter, ether extract, crude fiber and nitrogen-free extract as well as uptake of calcium and phosphorus, total body weight and average daily gain were similar (p>0.05) among the four groups. However, there was a trend of increase in Se absorption of the guinea pigs with the increasing levels of Se, in the groups given 0.2 and 0.3 ppm of Se. It can be concluded that requirement of Se in guinea pigs is 0.1 ppm, as supplementation of > or =0.1 ppm sodium selenite in the diet (having 0.1 ppm Se) did not enhanced their growth rate and nutrient utilization.

  8. The Thermodynamic Flow-Force Interpretation of Root Nutrient Uptake Kinetics: A Powerful Formalism for Agronomic and Phytoplanktonic Models.

    PubMed

    Le Deunff, Erwan; Tournier, Pierre-Henri; Malagoli, Philippe

    2016-01-01

    The ion influx isotherms obtained by measuring unidirectional influx across root membranes with radioactive or stable tracers are mostly interpreted by enzyme-substrate-like modeling. However, recent analyses from ion transporter mutants clearly demonstrate the inadequacy of the conventional interpretation of ion isotherms. Many genetically distinct carriers are involved in the root catalytic function. Parameters Vmax and Km deduced from this interpretation cannot therefore be regarded as microscopic parameters of a single transporter, but are instead macroscopic parameters (V[Formula: see text] and K[Formula: see text], apparent maximum velocity and affinity constant) that depend on weighted activities of multiple transporters along the root. The flow-force interpretation based on the thermodynamic principle of irreversible processes is an alternative macroscopic modeling approach for ion influx isotherms in which macroscopic parameters Lj (overall conductance of the root system for the substrate j) and πj (thermodynamic parameter when Jj = 0) have a straightforward meaning with respect to the biological sample studied. They characterize the efficiency of the entire root catalytic structure without deducing molecular characteristics. Here we present the basic principles of this theory and how its use can be tested and improved by changing root pre- and post-wash procedures before influx measurements in order to come as close as possible to equilibrium conditions. In addition, the constant values of Vm and Km in the Michaelis-Menten (MM) formalism of enzyme-substrate interpretation do not reflect variations in response to temperature, nutrient status or nutrient regimes. The linear formalism of the flow-force approach, which integrates temperature effect on nutrient uptake, could usefully replace MM formalism in the 1-3-dimension models of plants and phytoplankton. This formalism offers a simplification of parametrization to help find more realistic analytical

  9. Golgi N-glycan branching N-acetylglucosaminyltransferases I, V and VI promote nutrient uptake and metabolism

    PubMed Central

    Abdel Rahman, Anas M; Ryczko, Michael; Nakano, Miyako; Pawling, Judy; Rodrigues, Tania; Johswich, Anita; Taniguchi, Naoyuki; Dennis, James W

    2015-01-01

    Nutrient transporters are critical gate-keepers of extracellular metabolite entry into the cell. As integral membrane proteins, most transporters are N-glycosylated, and the N-glycans are remodeled in the Golgi apparatus. The Golgi branching enzymes N-acetylglucosaminyltransferases I, II, IV, V and avian VI (encoded by Mgat1, Mgat2, Mgat4a/b/c Mgat5 and Mgat6), each catalyze the addition of N-acetylglucosamine (GlcNAc) in N-glycans. Here, we asked whether N-glycan branching promotes nutrient transport and metabolism in immortal human HeLa carcinoma and non-malignant HEK293 embryonic kidney cells. Mgat6 is absent in mammals, but ectopic expression can be expected to add an additional β1,4-linked branch to N-glycans, and may provide evidence for functional redundancy of the N-glycan branches. Tetracycline (tet)-induced overexpression of Mgat1, Mgat5 and Mgat6 resulted in increased enzyme activity and increased N-glycan branching concordant with the known specificities of these enzymes. Tet-induced Mgat1, Mgat5 and Mgat6 combined with stimulation of hexosamine biosynthesis pathway (HBP) to UDP-GlcNAc, increased cellular metabolite levels, lactate and oxidative metabolism in an additive manner. We then tested the hypothesis that N-glycan branching alone might promote nutrient uptake when glucose (Glc) and glutamine are limiting. In low glutamine and Glc medium, tet-induced Mgat5 alone increased amino acids uptake, intracellular levels of glycolytic and TCA intermediates, as well as HEK293 cell growth. More specifically, tet-induced Mgat5 and HBP elevated the import rate of glutamine, although transport of other metabolites may be regulated in parallel. Our results suggest that N-glycan branching cooperates with HBP to regulate metabolite import in a cell autonomous manner, and can enhance cell growth in low-nutrient environments. PMID:25395405

  10. The Thermodynamic Flow-Force Interpretation of Root Nutrient Uptake Kinetics: A Powerful Formalism for Agronomic and Phytoplanktonic Models

    PubMed Central

    Le Deunff, Erwan; Tournier, Pierre-Henri; Malagoli, Philippe

    2016-01-01

    The ion influx isotherms obtained by measuring unidirectional influx across root membranes with radioactive or stable tracers are mostly interpreted by enzyme-substrate-like modeling. However, recent analyses from ion transporter mutants clearly demonstrate the inadequacy of the conventional interpretation of ion isotherms. Many genetically distinct carriers are involved in the root catalytic function. Parameters Vmax and Km deduced from this interpretation cannot therefore be regarded as microscopic parameters of a single transporter, but are instead macroscopic parameters (Vmapp and Kmapp, apparent maximum velocity and affinity constant) that depend on weighted activities of multiple transporters along the root. The flow-force interpretation based on the thermodynamic principle of irreversible processes is an alternative macroscopic modeling approach for ion influx isotherms in which macroscopic parameters Lj (overall conductance of the root system for the substrate j) and πj (thermodynamic parameter when Jj = 0) have a straightforward meaning with respect to the biological sample studied. They characterize the efficiency of the entire root catalytic structure without deducing molecular characteristics. Here we present the basic principles of this theory and how its use can be tested and improved by changing root pre- and post-wash procedures before influx measurements in order to come as close as possible to equilibrium conditions. In addition, the constant values of Vm and Km in the Michaelis-Menten (MM) formalism of enzyme-substrate interpretation do not reflect variations in response to temperature, nutrient status or nutrient regimes. The linear formalism of the flow-force approach, which integrates temperature effect on nutrient uptake, could usefully replace MM formalism in the 1-3-dimension models of plants and phytoplankton. This formalism offers a simplification of parametrization to help find more realistic analytical expressions and numerical

  11. Factors influencing the uptake of nutrients in streams within the New York City water-supply source areas.

    NASA Astrophysics Data System (ADS)

    Newbold, D.; Kaplan, L.; Bott, T.; Jackson, J.; Aufdenkampe, A.; Dow, C.

    2005-05-01

    The uptake of nutrients was measured in each of ten streams within the water supply source areas for New York City, once each year between 2000 and 2002. Uptake lengths were estimated from the conservative-tracer-corrected downstream attenuation of short-term (1-2 h) nutrient releases. Uptake lengths correlated with stream size and were converted to uptake velocities (Vf) for further analysis. Vf of phosphate, with a mean of 0.018 mm/s, fit Michaelis-Menten uptake kinetics with a half-saturation of 7 μg/L background phosphate. Vf of ammonium, with a mean of 0.58 mm/s, did not correlate with background ammonium concentration, but fit an uptake curve that used total dissolved nitrogen as the substrate, with a half-saturation of 1 mg/L. Vf of glucose and arabinose were not related to background concentrations. Vf for all four nutrients correlated with community respiration (CR) from diel oxygen variation. For phosphorus uptake, however, CR was collinear with background phosphorus. Vf for ammonium correlated with the macroinvertebrate-based Water Quality Score and Vf for both ammonium and phosphate correlated with some molecular tracers of anthropogenic sources. These results point to nutrient uptake as a sensitive integrator of water quality, ecosystem metabolism, and community structure.

  12. Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment

    SciTech Connect

    Shi, Zhenqing; Balogh-Brunstad, Zsuzsanna; Grant, Michael R.; Harsh, James B.; Gill, Richard; Thomashow, Linda; Dohnalkova, Alice; Stacks, Daryl; Letourneau, Melissa; Keller, Chester K.

    2014-01-10

    Background and Aims Plant nutrient uptake is affected by environmental stress, but how plants respond to cation-nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient limitation on cation uptake in an experimental plant-mineral system. Methods Column experiments, with red pine (Pinus resinosa Ait.) seedlings growing in sand/mineral mixtures, were conducted for up to nine months under a range of Ca- and K-limited conditions. The Ca and K were supplied from both minerals and nutrient solutions with varying Ca and K concentrations. Results Cation nutrient stress had little impact on carbon allocation after nine months of plant growth and K was the limiting nutrient for biomass production. The Ca/Sr and K/Rb ratio results allowed independent estimation of dissolution incongruency and discrimination against Sr and Rb during cation uptake processes. The fraction of K in biomass from biotite increased with decreasing K supply from nutrient solutions. The mineral anorthite was consistently the major source of Ca, regardless of nutrient treatment. Conclusions Red pine seedlings exploited more mineral K in response to more severe K deficiency. This did not occur for Ca. Plant discrimination factors must be carefully considered to accurately identify nutrient sources using cation tracers.

  13. Approaches in the determination of plant nutrient uptake and distribution in space flight conditions

    NASA Technical Reports Server (NTRS)

    Heyenga, A. G.; Forsman, A.; Stodieck, L. S.; Hoehn, A.; Kliss, M.

    2000-01-01

    The effective growth and development of vascular plants rely on the adequate availability of water and nutrients. Inefficiency in either the initial absorption, transportation, or distribution of these elements are factors which impinge on plant structure and metabolic integrity. The potential effect of space flight and microgravity conditions on the efficiency of these processes is unclear. Limitations in the available quantity of space-grown plant material and the sensitivity of routine analytical techniques have made an evaluation of these processes impractical. However, the recent introduction of new plant cultivating methodologies supporting the application of radionuclide elements and subsequent autoradiography techniques provides a highly sensitive investigative approach amenable to space flight studies. Experiments involving the use of gel based 'nutrient packs' and the radionuclides calcium-45 and iron-59 were conducted on the Shuttle mission STS-94. Uptake rates of the radionuclides between ground and flight plant material appeared comparable.

  14. Approaches in the Determination of Plant Nutrient Uptake and Distribution in Space Flight Conditions

    NASA Technical Reports Server (NTRS)

    Heyenga, A. G.; Forsman, A.; Stodieck, L. S.; Hoehn, A.; Kliss, Mark

    1998-01-01

    The effective growth and development of vascular plants rely on the adequate availability of water and nutrients. Inefficiency in either the initial absorption, transportation, or distribution of these elements are factors which may impinge on plant structure and metabolic integrity. The potential effect of space flight and microgravity conditions on the efficiency of these processes is unclear. Limitations in the available quantity of space-grown plant material and the sensitivity of routine analytical techniques have made an evaluation of these processes impractical. However, the recent introduction of new plant cultivating methodologies supporting the application of radionuclide elements and subsequent autoradiography techniques provides a highly sensitive investigative approach amenable to space flight studies. Experiments involving the use of gel based 'nutrient packs' and the nuclides Ca45 and Fe59 were conducted on the Shuttle mission STS-94. Uptake rates of the radionuclides between ground and flight plant material appeared comparable.

  15. Optimal allocation of building blocks between nutrient uptake systems in a microbe.

    PubMed

    van den Berg, Hugo A; Kiselev, Yuri N; Orlov, Michael V

    2002-03-01

    A bacterial cell must distribute its molecular building blocks among various types of nutrient uptake systems. If the microbe is to maximize its average growth rate, this allocation of building blocks must be adjusted to the environmental availabilities of the various nutrients. The adjustments can be found from growth balancing considerations. We give a full proof of optimality and uniqueness of the optimal allocation regime for a simple model of microbial growth and internal stores kinetics. This proof suggests likely candidates for optimal control regimes in the case of a more realistic model. These candidate regimes differ with respect to the information that the cell's control system must have access to. We pay particular attention to one of the three candidates, a feedback regime based on a cellular control system that monitors only internal reserve densities. We show that allocation converges rapidly to balanced growth under this control regime.

  16. Plasticity in N uptake among sympatric species with contrasting nutrient acquisition strategies in a tropical forest.

    PubMed

    Andersen, Kelly M; Mayor, Jordan R; Turner, Benjamin L

    2017-03-06

    Nitrogen (N) availability influences the productivity and distribution of plants in tropical montane forests. Strategies to acquire soil N, such as direct uptake of organic compounds or associations with root symbionts to enhance N acquisition in exchange for carbon (C), may facilitate plant species coexistence and ecosystem N retention. Alternatively, rapid microbial turnover of soil N forms in tropical soils might promote flexible plant N-uptake strategies and mediate species coexistence. We tested whether sympatric plant species with divergent root symbiont associations, and therefore potentially different nutrient acquisition strategies, partition chemical forms of N or show plasticity in N uptake in a tropical pre-montane forest in Panama. We traced the movement of three (15) N forms into soil pools, microbes, and seedlings of eleven species differing in root traits. Seedlings were grown in a split-plot field transplant experiment, with plots receiving equimolar mixtures of ammonium, nitrate, and glycine, with one form isotopically labeled in each block. After 48-hours, more (15) N was recovered in microbes than in plants, while all pools (extractable organic and inorganic N, microbial biomass, and leaves) contained greater amounts of (15) N from nitrate than from ammonium or glycine. Furthermore, (13) C from dual-labeled glycine was not recovered in the leaves of any seedlings, suggesting the studied species do not directly take up organic N or transform organic N prior to translocation to leaves. Nitrogen uptake differed by root symbiont group only for nitrate, with greater (15) N recovery in plants with arbuscular mycorrhizal (AM) associations or proteoid roots compared to orchids. Some root trait groups differed in (15) N recovery among N forms, with greater nitrate uptake than ammonium or glycine by AM-associated and N2 -fixing plants. However, only five of eleven species showed differences in uptake among N forms. Our results indicate flexibility in

  17. Summer cover crops and soil amendments to improve growth and nutrient uptake of okra

    SciTech Connect

    Wang, Q.R.; Li, Y.C.; Klassen, W.

    2006-04-15

    A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on 'Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudan-grass (Sorghum bicolor x S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash), coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. The results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.

  18. Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse

    NASA Astrophysics Data System (ADS)

    den Haan, Joost; Huisman, Jef; Brocke, Hannah J.; Goehlich, Henry; Latijnhouwers, Kelly R. W.; van Heeringen, Seth; Honcoop, Saskia A. S.; Bleyenberg, Tanja E.; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J. A.; Visser, Petra M.

    2016-06-01

    Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs.

  19. Nitrogen and phosphorus uptake rates of different species from a coral reef community after a nutrient pulse

    PubMed Central

    den Haan, Joost; Huisman, Jef; Brocke, Hannah J.; Goehlich, Henry; Latijnhouwers, Kelly R. W.; van Heeringen, Seth; Honcoop, Saskia A. S.; Bleyenberg, Tanja E.; Schouten, Stefan; Cerli, Chiara; Hoitinga, Leo; Vermeij, Mark J. A.; Visser, Petra M.

    2016-01-01

    Terrestrial runoff after heavy rainfall can increase nutrient concentrations in waters overlying coral reefs that otherwise experience low nutrient levels. Field measurements during a runoff event showed a sharp increase in nitrate (75-fold), phosphate (31-fold) and ammonium concentrations (3-fold) in waters overlying a fringing reef at the island of Curaçao (Southern Caribbean). To understand how benthic reef organisms make use of such nutrient pulses, we determined ammonium, nitrate and phosphate uptake rates for one abundant coral species, turf algae, six macroalgal and two benthic cyanobacterial species in a series of laboratory experiments. Nutrient uptake rates differed among benthic functional groups. The filamentous macroalga Cladophora spp., turf algae and the benthic cyanobacterium Lyngbya majuscula had the highest uptake rates per unit biomass, whereas the coral Madracis mirabilis had the lowest. Combining nutrient uptake rates with the standing biomass of each functional group on the reef, we estimated that the ammonium and phosphate delivered during runoff events is mostly taken up by turf algae and the two macroalgae Lobophora variegata and Dictyota pulchella. Our results support the often proposed, but rarely tested, assumption that turf algae and opportunistic macroalgae primarily benefit from episodic inputs of nutrients to coral reefs. PMID:27353576

  20. Effects of arginine on intestinal epithelial cell integrity and nutrient uptake.

    PubMed

    Xia, Mi; Ye, Lulu; Hou, Qihang; Yu, Qinghua

    2016-11-14

    Arginine is a multifaceted amino acid that is critical to the normal physiology of the gastrointestinal tract. Oral arginine administration has been shown to improve mucosal recovery following intestinal injury. The present study investigated the influence of extracellular arginine concentrations on epithelial cell barrier regulation and nutrition uptake by porcine small intestinal epithelial cell line (IPEC-J2). The results show that reducing arginine concentration from 0·7 to 0·2 mm did not affect the transepithelial electrical resistance value, tight-junction proteins (claudin-1, occludin, E-cadherin), phosphorylated extracellular signal-regulated protein kinases (p-ERK) and mucin-1 expression. Furthermore, reducing arginine concentration stimulated greater expression of cationic amino acid transporter (CAT1), excitatory amino acid transporter (EAAT3) and alanine/serine/cysteine transporter (ASCT1) mRNA by IPEC-J2 cells, which was verified by elevated efficiency of amino acid uptake. Glucose consumption by IPEC-J2 cells treated with 0·2 mm-arginine remained at the same physiological level to guarantee energy supply and to maintain the cell barrier. This experiment implied that reducing arginine concentration is feasible in IPEC-J2 cells guaranteed by nutrient uptake and cell barrier function.

  1. Elemental uptake and distribution of nutrients in avocado mesocarp and the impact of soil quality.

    PubMed

    Reddy, Mageshni; Moodley, Roshila; Jonnalagadda, Sreekanth B

    2014-07-01

    The distribution of 14 elements (both essential and non-essential) in the Hass and Fuerte cultivars of avocados grown at six different sites in KwaZulu-Natal, South Africa, was investigated. Soils from the different sites were concurrently analysed for elemental concentration (both total and exchangeable), pH, organic matter and cation exchange capacity. In both varieties of the fruit, concentrations of the elements Cd, Co, Cr, Pb and Se were extremely low with the other elements being in decreasing order of Mg > Ca > Fe > Al > Zn > Mn > Cu > Ni > As. Nutritionally, avocados were found to be a good dietary source of the micronutrients Cu and Mn. In soil, Pb concentrations indicated enrichment (positive geoaccumuluation indices) but this did not influence uptake of the metal by the plant. Statistical analysis was done to evaluate the impact of soil quality parameters on the nutrient composition of the fruits. This analysis indicated the prevalence of complex metal interactions at the soil-plant interface that influenced their uptake by the plant. However, the plant invariably controlled metal uptake according to metabolic needs as evidenced by their accumulation and exclusion.

  2. Uptake, release, and absorption of nutrients into the marine environment by the green mussel (Perna viridis).

    PubMed

    Srisunont, Chayarat; Babel, Sandhya

    2015-08-15

    The nutrient uptake and release by the mussels in relation with amount of food consumption are emphasised in this research. Results of the study demonstrate that about 16% of the total mass dry weight food consumed by the mussels was released as faeces. The depositions of particulate carbon, nitrogen, and phosphorus in mussel faeces were found to be 26.3, 5.7, and 0.6mg/day/indv respectively. Soluble inorganic nutrients such as NH4(+)-N (2.5mg/day/indv), and PO4(3-)-P (0.6mg/day/indv) were also released as mussel excretion. The nutrient absorption efficiency for the green mussel body was found to be 65.1% for carbon, 62.1% for nitrogen, and 79.2% for phosphorus. Subsequently, green mussels can remove particulate carbon, nitrogen and phosphorus at 108.1, 13.5, and 4.6mg/day/indv from aquatic systems. Finally, the results can help in estimating the carrying capacity of mussel cultivation without deteriorating the water quality in marine ecosystems.

  3. [Effects of rhizosphere soil permeability on water and nutrient uptake by maize].

    PubMed

    Niu, Wen-quan; Guo, Chao

    2010-11-01

    Aimed to better understand the significance of soil microenvironment in crop growth, a pot experiment was conducted to investigate the effects of rhizosphere soil permeability on the water and nutrient uptake by maize. Under three irrigation levels (600, 400, and 200 ml per pot), three treatments of soil aeration (no tube aeration as the control, tube aeration every two days, and tube aeration every four days) were installed, and the physiological indices of maize were measured. Under the same irrigation levels, soil aeration increased the plant height, leaf area, chlorophyll contents, promoted nutrient adsorption and increased root vitality markedly. At elongation stage, treatment tube aeration every four days had the highest root vitality (8.24 mg x g(-1) x h(-1)) under the irrigation level 600 ml per pot, being significantly higher (66.7%) than that (4.94 mg x g(-1) x h(-1)) of the control. Soil aeration had no significant effects on the transpiration rate of maize, indicating that rhizosphere soil aeration could raise water and nutrient use efficiency, and improve maize growth.

  4. Toward a universal mass-momentum transfer relationship for predicting nutrient uptake and metabolite exchange in benthic reef communities

    NASA Astrophysics Data System (ADS)

    Falter, James L.; Lowe, Ryan J.; Zhang, Zhenlin

    2016-09-01

    Here we synthesize data from previous field and laboratory studies describing how rates of nutrient uptake and metabolite exchange (mass transfer) are related to form drag and bottom stresses (momentum transfer). Reanalysis of this data shows that rates of mass transfer are highly correlated (r2 ≥ 0.9) with the root of the bottom stress (τbot0.4) under both waves and currents and only slightly higher under waves (~10%). The amount of mass transfer that can occur per unit bottom stress (or form drag) is influenced by morphological features ranging anywhere from millimeters to meters in scale; however, surface-scale roughness (millimeters) appears to have little effect on actual nutrient uptake by living reef communities. Although field measurements of nutrient uptake by natural reef communities agree reasonably well with predictions based on existing mass-momentum transfer relationships, more work is needed to better constrain these relationships for more rugose and morphologically complex communities.

  5. Effects of elevated CO/sub 2/ and nutrient stress on nitrogen and phosphorus uptake and use efficiencies

    SciTech Connect

    Cure, J.D.; Israel, D.W.; Rufty, T.W.

    1987-04-01

    Earlier they reported that non-nodulating Lee soybeans growing in complete nutrient solution showed decreased nutrient uptake efficiency (mg N or P/g root) at early pod fill when exposed to elevated CO/sub 2/. In order to look at CO/sub 2//nutrient interactions over time, plants were grown in growth chambers with nutrient solutions containing 10 mM N/1 mM P (controls) or 10 mM N/0.1 mM P (low P) or 0.5 mM N/1 mMP (low N) and exposed to either 350 or 700 ..mu..L/L CO/sub 2/. Uptake efficiencies for N and P of the control plants showed a pronounced positive response to high CO/sub 2/ in early growth stages, which diminished with time and then became negative. This trend was also present for the low N and low P plants. Nutrient use efficiency, however, was increased by day 7 (first harvest) by high CO/sub 2/ and the effect was sustained through the vegetative period. The N and P stresses produced contrasting responses: low P availability caused an increase in P use efficiency, whereas low N caused a decrease in N use efficiency. These effects resulted from P uptake beyond the requirement for growth, a pattern not observed for N uptake.

  6. Additive effects due to biochar and endophyte application enable soybean to enhance nutrient uptake and modulate nutritional parameters* #

    PubMed Central

    Waqas, Muhammad; Kim, Yoon-Ha; Khan, Abdul Latif; Shahzad, Raheem; Asaf, Sajjad; Hamayun, Muhammad; Kang, Sang-Mo; Khan, Muhammad Aaqil; Lee, In-Jung

    2017-01-01

    We studied the effects of hardwood-derived biochar (BC) and the phytohormone-producing endophyte Galactomyces geotrichum WLL1 in soybean (Glycine max (L.) Merr.) with respect to basic, macro-and micronutrient uptakes and assimilations, and their subsequent effects on the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and 1,1-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity. The assimilation of basic nutrients such as nitrogen was up-regulated, leaving carbon, oxygen, and hydrogen unaffected in BC+G. geotrichum-treated soybean plants. In comparison, the uptakes of macro-and micronutrients fluctuated in the individual or co-application of BC and G. geotrichum in soybean plant organs and rhizospheric substrate. Moreover, the same attribute was recorded for the regulation of functional amino acids, isoflavones, fatty acid composition, total sugar contents, total phenolic contents, and DPPH-scavenging activity. Collectively, these results showed that BC+G. geotrichum-treated soybean yielded better results than did the plants treated with individual applications. It was concluded that BC is an additional nutriment source and that the G. geotrichum acts as a plant biostimulating source and the effects of both are additive towards plant growth promotion. Strategies involving the incorporation of BC and endophytic symbiosis may help achieve eco-friendly agricultural production, thus reducing the excessive use of chemical agents. PMID:28124840

  7. Inhibition of nitrification in municipal wastewater-treating photobioreactors: Effect on algal growth and nutrient uptake.

    PubMed

    Krustok, I; Odlare, M; Truu, J; Nehrenheim, E

    2016-02-01

    The effect of inhibiting nitrification on algal growth and nutrient uptake was studied in photobioreactors treating municipal wastewater. As previous studies have indicated that algae prefer certain nitrogen species to others, and because nitrifying bacteria are inhibited by microalgae, it is important to shed more light on these interactions. In this study allylthiourea (ATU) was used to inhibit nitrification in wastewater-treating photobioreactors. The nitrification-inhibited reactors were compared to control reactors with no ATU added. Microalgae had higher growth in the inhibited reactors, resulting in a higher chlorophyll a concentration. The species mix also differed, with Chlorella and Scenedesmus being the dominant genera in the control reactors and Cryptomonas and Chlorella dominating in the inhibited reactors. The nitrogen speciation in the reactors after 8 days incubation was also different in the two setups, with N existing mostly as NH4-N in the inhibited reactors and as NO3-N in the control reactors.

  8. Liquid Organic Fertilizers for Sustainable Agriculture: Nutrient Uptake of Organic versus Mineral Fertilizers in Citrus Trees.

    PubMed

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Bermejo, Almudena; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    The main objective of this study was to compare the performance of two liquid organic fertilizers, an animal and a plant-based fertilizer, with mineral fertilization on citrus trees. The source of the fertilizer (mineral or organic) had significant effect in the nutritional status of the organic and conventionally managed mandarins. Nutrient uptake, vegetative growth, carbohydrate synthesis and soil characteristics were analyzed. Results showed that plants fertilized with animal based liquid fertilizers exhibited higher total biomass with a more profuse development of new developing organs (leaves and fibrous roots). Liquid organic fertilization resulted in an increased uptake of macro and micronutrients compared to mineral fertilized trees. Moreover, organic fertilization positively affected the carbohydrate content (fructose, glucose and sucrose) mainly in summer flush leaves. Liquid organic fertilization also resulted in an increase of soil organic matter content. Animal-based fertilizer, due to intrinsic composition, increased total tree biomass and carbohydrate leaves content, and led to lower soil nitrate concentration and higher P and Mg exchangeable in soil extract compared to vegetal-based fertilizer. Therefore, liquid organic fertilizers could be used as an alternative to traditional mineral fertilization in drip irrigated citrus trees.

  9. Liquid Organic Fertilizers for Sustainable Agriculture: Nutrient Uptake of Organic versus Mineral Fertilizers in Citrus Trees

    PubMed Central

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Bermejo, Almudena; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    The main objective of this study was to compare the performance of two liquid organic fertilizers, an animal and a plant-based fertilizer, with mineral fertilization on citrus trees. The source of the fertilizer (mineral or organic) had significant effect in the nutritional status of the organic and conventionally managed mandarins. Nutrient uptake, vegetative growth, carbohydrate synthesis and soil characteristics were analyzed. Results showed that plants fertilized with animal based liquid fertilizers exhibited higher total biomass with a more profuse development of new developing organs (leaves and fibrous roots). Liquid organic fertilization resulted in an increased uptake of macro and micronutrients compared to mineral fertilized trees. Moreover, organic fertilization positively affected the carbohydrate content (fructose, glucose and sucrose) mainly in summer flush leaves. Liquid organic fertilization also resulted in an increase of soil organic matter content. Animal-based fertilizer, due to intrinsic composition, increased total tree biomass and carbohydrate leaves content, and led to lower soil nitrate concentration and higher P and Mg exchangeable in soil extract compared to vegetal-based fertilizer. Therefore, liquid organic fertilizers could be used as an alternative to traditional mineral fertilization in drip irrigated citrus trees. PMID:27764099

  10. Oxygen, sulphide and nutrient uptake of the mangrove mud clam Anodontia edentula (Family: Lucinidae).

    PubMed

    Lebata, M J

    2001-11-01

    Oxygen, sulphide and nutrient (ammonia, nitrite and phosphate) uptake of Anodontia edentula was measured. Oxygen and sulphide were measured from sealed containers provided with 1 l fresh mangrove mud (sulphide source) and seawater (oxygen source) with two treatments (with and without clam) at 16 replicates each. Oxygen, sulphide and other parameters were measured at days 1 (initial), 3 and 5 (final). Nutrients were measured from containers filled with 1.5 l wastewater from a milkfish broodstock tank with two treatments (with and without clam) at eight replicates each. Ammonia, NO2 and P04 were measured at days 0 (initial) 3, 6, 9 and 12 (final). Results showed significantly decreasing oxygen and sulphide concentrations in treatment with clams (ANOVA, p < 0.001). A significantly higher ammonia concentration (ANOVA, p < 0.05) was observed in treatment with clams while no significant difference was observed in nitrite and phosphate between the two treatments. A decreasing ammonia and an increasing nitrite trend was also observed in both treatments starting at day 3.

  11. Efficacies of designer biochars in improving biomass and nutrient uptake of winter wheat grown in a hard setting subsoil layer.

    PubMed

    Sigua, G C; Novak, J M; Watts, D W; Johnson, M G; Spokas, K

    2016-01-01

    In the Coastal Plains region of the United States, the hard setting subsoil layer of Norfolk soils results in low water holding capacity and nutrient retention, which often limits root development. In this region, the Norfolk soils are under intensive crop production that further depletes nutrients and reduces organic carbon (C). Incorporation of pyrolyzed organic residues or "biochars" can provide an alternative recalcitrant C source. However, biochar quality and effect can be inconsistent and different biochars react differently in soils. We hypothesized that addition of different designer biochars will have variable effects on biomass and nutrient uptake of winter wheat. The objective of this study was to investigate the effects of designer biochars on biomass productivity and nutrient uptake of winter wheat (Triticum aestivum L.) in a Norfolk's hard setting subsoil layer. Biochars were added to Norfolk's hard setting subsoil layer at the rate of 40 Mg ha(-1). The different sources of biochars were: plant-based (pine chips, PC); animal-based (poultry litter, PL); 50:50 blend (50% PC:50% PL); 80:20 blend (80% PC:20% PL); and hardwood (HW). Aboveground and belowground biomass and nutrient uptake of winter wheat varied significantly (p⩽0.0001) with the different designer biochar applications. The greatest increase in the belowground biomass of winter wheat over the control was from 80:20 blend of PC:PL (81%) followed by HW (76%), PC (59%) and 50:50 blend of PC:PL (9%). However, application of PL resulted in significant reduction of belowground biomass by about 82% when compared to the control plants. The average uptake of P, K, Ca, Mg, Na, Al, Fe, Cu and Zn in both the aboveground and belowground biomass of winter wheat varied remarkably with biochar treatments. Overall, our results showed promising significance for the treatment of a Norfolk's hard setting subsoil layer since designer biochars did improve both aboveground/belowground biomass and nutrient uptake

  12. The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake

    PubMed Central

    Sherling, Emma S; Knuepfer, Ellen; Brzostowski, Joseph A; Miller, Louis H; Blackman, Michael J; van Ooij, Christiaan

    2017-01-01

    Merozoites of the protozoan parasite responsible for the most virulent form of malaria, Plasmodium falciparum, invade erythrocytes. Invasion involves discharge of rhoptries, specialized secretory organelles. Once intracellular, parasites induce increased nutrient uptake by generating new permeability pathways (NPP) including a Plasmodium surface anion channel (PSAC). RhopH1/Clag3, one member of the three-protein RhopH complex, is important for PSAC/NPP activity. However, the roles of the other members of the RhopH complex in PSAC/NPP establishment are unknown and it is unclear whether any of the RhopH proteins play a role in invasion. Here we demonstrate that RhopH3, the smallest component of the complex, is essential for parasite survival. Conditional truncation of RhopH3 substantially reduces invasive capacity. Those mutant parasites that do invade are defective in nutrient import and die. Our results identify a dual role for RhopH3 that links erythrocyte invasion to formation of the PSAC/NPP essential for parasite survival within host erythrocytes. DOI: http://dx.doi.org/10.7554/eLife.23239.001 PMID:28252384

  13. Application of microbial inoculants promote plant growth, increased nutrient uptake and improve root morphology of corn plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reducing fertilizers impacts from agriculture is a world-wide concern, both from an environmental and human health perspective. One way to reduce impacts of fertilizers is by enhancing plant uptake which improves nutrient use efficiency and also potentially reduce the amounts of fertilizer needed. ...

  14. Irrigation frequency during container production alters Rhodendron growth, nutrient uptake, and flowering after transplanting into a landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of irrigation frequency (same amount of water per day given at different times) and nitrogen (N) fertilizer application rate during container on nutrient uptake, growth (biomass) and flowering of evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhod...

  15. Irrigation frequency alters nutrient uptake in container-grown Rhododendron plants grown with different rates of nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of irrigation frequency (same amount of water per day given at different times) on nutrient uptake of container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ) grown with different rates of nitrogen (N) fertilize...

  16. The effects of weed-crop competition on nutrient uptake as affected by crop rotation and fertilizers.

    PubMed

    Mohammaddoust-E-Chamanabad, Hamid Reza; Asghari, Ali; Tulikov, Aleksander Mikhailovic

    2007-11-15

    A field study at the Agricultural University of Timiriazev, Moscow, was conducted to determine the effect of crop rotation and Long-term fertilizer application on differences in the competitive ability of spring barley and weeds to nutrient uptake in 2004 and 2005. Spring barley was cultivated in continuous and in crop rotation with winter rye, potato, clover, flax and fallow, with and without NPK application since 1912. Spring barley, especially in no fertilizer plots grown in crop rotation has greater dry mass than spring barley grown in continuous. While dry weed mass markedly decreased in crop rotation. Decrease dry weeds mass was greater when NPK had applied. The statistical analyses show that when spring barley grew in competition with weeds in the no fertilizer plots, crop rotation significantly increased nutrient content in spring barley, but when fertilizer applied the content of N, P2O5 and K2O in barley did not change. Lowest weeds nutrient content observed where soil fertility was increased by crop rotation and NPK application. Crop rotation significantly increased total nutrient uptake of soils by spring barley, but decreased total nutrient uptake by weeds.

  17. Ion Uptake Determination of Dendrochronologically-Dated Trees Using Neutron Activation Analysis

    SciTech Connect

    Kenan Unlu; P.I. Kuniholm; D.K.H. Schwarz; N.O. Cetiner; J.J. Chiment

    2009-03-30

    Uptake of metal ions by plan roots is a function of the type and concentration of metal in the soil, the nutrient biochemistry of the plant, and the immediate environment of the root. Uptake of gold (Au) is known to be sensitive to soil pH for many species. Soil acidification due to acid precipitation following volcanic eruptions can dramatically increase Au uptake by trees. Identification of high Au content in tree rings in dendrochronologically-dated, overlapping sequences of trees allows the identification of temporally-conscribed, volcanically-influenced periods of environmental change. Ion uptake, specifically determination of trace amounts of gold, was performed for dendrochronologically-dated tree samples utilizing Neutron Activation Analysis (NAA) technique. The concentration of gold was correlated with known enviironmental changes, e.g. volcanic activities, during historic periods.

  18. Plant uptake of cations under nutrient limitation: An environmental tracer study using Ca/Sr and K/Rb ratios

    NASA Astrophysics Data System (ADS)

    Shi, Z.; Keller, C. K.; Stacks, D.; Grant, M.; Harsh, J. B.; Letourneau, M.; Gill, R. A.; Balogh-Brunstad, Z.; Thomashow, L.; Dohnalkova, A.

    2012-12-01

    Vascular plant growth builds soils and ecosystem nutrient capital by sequestering and partitioning atmospheric CO2 into organic matter and continental runoff and driving terrestrial water and energy balances. Plant root-system functions, e.g. nutrient mobilization and uptake, are altered by environmental stress. However, the stress-response relationships are poorly understood. Chemical tracers have potential for assessing contributions of nutrients from various nutrient pools. Our objective is to quantitatively study how varying degrees of nutrient limitation (and corresponding needs to extract base cations from mineral sources) influence Ca and K uptake functions in a plant-root-mineral system. We are studying plant-driven mineral weathering in column experiments with red pine (Pinus resinosa) seedlings. The columns contain quartz sand amended with anorthite and biotite that constitute the sole mineral sources of Ca and K. These minerals also contain known amounts of Sr and Rb, which exhibit chemical behavior similar to Ca and K, respectively. The solution source of Ca and K was varied by adding 0% (no dissolved Ca and K), 10%, 30%, or 100% of a full strength Ca and K nutrient solution through irrigation water in which both Sr and Rb concentrations were negligible. Selected columns were destructively sampled at 3, 6 and 9 months to harvest biomass and measure plant uptake of cations. We used Ca/Sr and K/Rb ratio results to estimate the contributions of Ca and K from mineral and solution sources. For the 0% nutrient treatment, the Ca/Sr and K/Rb ratios in total biomass at 3 months, compared with those in the mineral phases, suggested preferential uptake of Ca and K over Sr and Rb, respectively, and allowed us to determine uptake discrimination factors for both cations. The K/Rb ratios in total biomass increased with greater K availability in the solution source, as expected, but Ca/Sr ratios did not show any dependence on Ca availability in the solution source

  19. The role of carbon in fungal nutrient uptake and transport: implications for resource exchange in the arbuscular mycorrhizal symbiosis.

    PubMed

    Fellbaum, Carl R; Mensah, Jerry A; Pfeffer, Philip E; Kiers, E Toby; Bücking, Heike

    2012-11-01

    The arbuscular mycorrhizal (AM) symbiosis, which forms between plant hosts and ubiquitous soil fungi of the phylum Glomeromycota, plays a key role for the nutrient uptake of the majority of land plants, including many economically important crop species. AM fungi take up nutrients from the soil and exchange them for photosynthetically fixed carbon from the host. While our understanding of the exact mechanisms controlling carbon and nutrient exchange is still limited, we recently demonstrated that (i) carbon acts as an important trigger for fungal N uptake and transport, (ii) the fungus changes its strategy in response to an exogenous supply of carbon, and that (iii) both plants and fungi reciprocally reward resources to those partners providing more benefit. Here, we summarize recent research findings and discuss the implications of these results for fungal and plant control of resource exchange in the AM symbiosis.

  20. Modulation of the uptake of critical nutrients by breast cancer cells by lactate: Impact on cell survival, proliferation and migration.

    PubMed

    Guedes, Marta; Araújo, João R; Correia-Branco, Ana; Gregório, Inês; Martel, Fátima; Keating, Elisa

    2016-02-15

    This work aimed to characterize the uptake of folate and glucose by breast cancer cells and to study the effect of lactate upon the transport of these nutrients and upon cell viability, proliferation and migration capacity. Data obtained showed that: a) MCF7 cells uptake (3)H-folic acid ((3)H-FA) at physiological but not at acidic pH; b) T47D cells accumulate (3)H-FA and (14)C-5-methyltetrahydrofolate ((14)C-5-MTHF) more efficiently at acidic than at physiological pH; c) (3)H-deoxyglucose ((3)H-DG) uptake by T47D cells is sodium-independent, inhibited by cytochalasin B (CYT B) and stimulated by insulin. Regarding the effect of lactate, in T47D cells, acute (26 min) and chronic (24 h) exposure to lactic acid (LA) stimulated (3)H-FA uptake. Acute exposure to LA also stimulated (3)H-DG uptake and chronic exposure to LA significantly stimulated T47D cell migratory capacity. In conclusion, the transport of folates is strikingly different in two phenotypically similar breast cancer cell lines: MCF7 and T47D cells. Additionally, lactate seems to act as a signaling molecule which increases the uptake of nutrients and promotes the migration capacity of T47D cells.

  1. Similarity of nutrient uptake and root dimensions of Engelmann spruce and subalpine fir at two contrasting sites in Colorado

    SciTech Connect

    Yanai, R; McFarlane, K; Lucash, M; Kulpa, S; Wood, D

    2009-10-09

    Nutrient uptake capacity is an important parameter in modeling nutrient uptake by plants. Researchers commonly assume that uptake capacity measured for a species can be used across sites. We tested this assumption by measuring the nutrient uptake capacity of intact roots of Engelmann spruce (Picea engelmanni Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) at Loch Vale Watershed and Fraser Experimental Forest in the Rocky Mountains of central Colorado. Roots still attached to the tree were exposed to one of three concentrations of nutrient solutions for time periods ranging from 1 to 96 hours, and solutions were analyzed for ammonium, nitrate, calcium, magnesium, and potassium. Surprisingly, the two species were indistinguishable in nutrient uptake within site for all nutrients (P > 0.25), but uptake rates differed by site. In general, nutrient uptake was higher at Fraser (P = 0.01, 0.15, 0.03, 0.18 for NH{sub 4}{sup +}, NO{sub 3}{sup -}, Ca{sup 2+}, and K{sup +}, respectively), which is west of the Continental Divide and has lower atmospheric deposition of N than Loch Vale. Mean uptake rates by site for ambient solution concentrations were 0.12 {micro}mol NH{sub 4}{sup +} g{sub fwt}{sup -1} h{sup -1}, 0.02 {micro}mol NO{sub 3}{sup -} g{sub fwt}{sup -1}, 0.21 {micro}mol Ca{sup 2+} g{sub fwt}{sup -1} h{sup -1}, and 0.01 {micro}mol Mg{sup 2+} g{sub fwt}{sup -1} h{sup -1} at Loch Vale, and 0.21 {micro}mol NH{sub 4}{sup +} f{sub fwt}{sup -1}h{sup -1}, 0.04 {micro}mol NO{sub 3}{sup -} g{sub fwt}{sup -1} h{sup -1}, 0.51 {micro}mol Ca{sup 2+}g{sub fwt}{sup -1}h{sup -1}, and 0.07 {micro}mol Mg{sup 2+} f{sub fwt}{sup -1}h{sup -1} at Fraser. The importance of site conditions in determining uptake capacity should not be overlooked when parameterizing nutrient uptake models. We also characterized the root morphology of these two species and compared them to other tree species we have measured at various sites in the northeastern USA. Engelman spruce and subalpine fir

  2. [Pb, Zn accumulation and nutrient uptake of 15 plant species grown in abandoned mine tailings].

    PubMed

    Shi, Xiang; Chen, Yi-Tai; Wang, Shu-Feng; Li, Jiang-Chuan

    2012-06-01

    Vegetation restoration field test was carried out in the abandoned lead-zinc tailings for 3 years. The study showed that accumulation of lead (Pb), zinc (Zn) and nutrient uptake differed with plant species and organs, heavy metals, and planting time. Pb was mainly accumulated in tree roots, and its content distribution in tree organs was generally in the order of roots > leaves > stems. But Zn concentrations in leaves of several tree species were higher than those in roots and stems. Within the tested 15 species, Cercis Canadensis had the highest concentrations of Pb and Zn in roots (1 803 and 2120 mg x kg(-1), respectively). Rhus chinensis had the highest Pb concentration in stems and leaves (280 and 546 mg x kg(-1), respectively) and Zn concentration (1 507 mg x kg(-1)) in leaves. Zn concentration in stems and leaves of Salix matsudana (729 and 1 153 mg x kg(-1), respectively) were the highest. Among the tested 15 species, TF values for Pb of Liquidambar formosana, Medicago sativa, and for Zn of Salix matsudana, Rhus chinensis, Medicago sativa were higher than 1. BCF values for Pb were all lower than 0.17, while that for Zn were all lower than 0.44. The N contents in nitrogen-fixing plants, P contents in Rhus typhina and Ailanthus altissima, and K content in Nerium indicum were significantly higher than those in other plants. With the increase of planting time, concentrations of heavy metal in plant body increased significantly; however the inverse trend were observed in nutritional element content. The species have higher metal accumulation capacity, such as Rhus chinensis, Salix matsudana and those nitrogen-fixing plants have higher tolerance to metal contamination and nutrient deficiency, such as Amorpha fruticosa, Medicago sativa, Lespedeza cuneata, and Alnus cremastogyne, they were suitable as the phytostabilizers in abandoned mine tailings.

  3. Sodium Stimulation of Uptake Hydrogenase Activity In Symbiotic Rhizobium1

    PubMed Central

    Kapulnik, Yoram; Phillips, Donald A.

    1986-01-01

    Initial observations showed a 100% increase in H2-uptake (Hup) activity of Rhizobium leguminosarum strain 3855 in pea root nodules (Pisum sativum L. cv Alaska) on plants growing in a baked clay substrate relative to those growing in vermiculite, and an investigation of nutrient factors responsible for the phenomenon was initiated. Significantly greater Hup activity was first measured in the clay-grown plants 24 days after germination, and higher activity was maintained relative to the vermiculite treatment until experiments were terminated at day 32. The increase in Hup activity was associated with a decrease in H2 evolution for plants with comparable rates of acetylene reduction. Analyses of the clay showed that it contained more Na+ (29 versus 9 milligrams per kilogram) and less K+ (6 versus 74 milligrams per kilogram) than the vermiculite. Analyses of plants, however, showed a large increase in Na+ concentration of clay-grown plants with a much smaller reduction in K+ concentration. In tests with the same organisms in a hydroponic system with controlled pH, 40 millimolar NaCl increased Hup activity more than 100% over plants grown in solutions lacking NaCl. Plants with increased Hup activity, however, did not have greater net carbon or total nitrogen assimilation. KCl treatments from 5 to 80 millimolar produced slight increased in Hup activity at 10 millimolar KCl, and tests with other salts in the hydroponic system indicated that only Na+ strongly promoted Hup activity. Treating vermiculite with 50 millimolar NaCl increased Na+ concentration in pea plant tissue and greatly promoted Hup activity of root nodules in a manner analogous to the original observation with the clay rooting medium. A wider generality of the phenomenon was suggested by demonstrating that exogenous Na+ increased Hup activity of other R. leguminosarum strains and promoted Hup activity of R. meliloti strain B300 in alfalfa (Medicago sativa L.). PMID:16665057

  4. Strategic enhancement of algal biomass, nutrient uptake and lipid through statistical optimization of nutrient supplementation in coupling Scenedesmus obliquus-like microalgae cultivation and municipal wastewater treatment.

    PubMed

    Zhang, Chunmin; Zhang, Yalei; Zhuang, Baolu; Zhou, Xuefei

    2014-11-01

    Supplementing proper nutrients could be a strategy for enhancing algal biomass, nutrients uptake and lipid accumulation in the coupling system of biodiesel production and municipal wastewater treatment. However, there is scant information reporting systematic studies on screening and optimization of key supplemented components in the coupling system. The main factors were scientifically screened and optimized using statistical methods. Plackett-Burman design (PBD) was used to explore the roles of added nutrient factors, whereas response surface methodology (RSM) was employed for optimization. Based on the statistic analysis, the optimum added TP and FeCl3·6H2O concentrations for Scenedesmus obliquus-like microalgae growth, nutrients uptake and lipid accumulation were 4.41 mg L(-1) and 6.48 mg L(-1), respectively. The corresponding biomass, lipid content and TN/TP removal efficiency were 1.46 g L(-1), 36.26% and >99%. The predicted value agreed well with the experimental value, as determined by validation experiments, which confirmed the availability and accuracy of the model.

  5. Land application of domestic effluent onto four soil types: plant uptake and nutrient leaching.

    PubMed

    Barton, L; Schipper, L A; Barkle, G F; McLeod, M; Speir, T W; Taylor, M D; McGill, A C; van Schaik, A P; Fitzgerald, N B; Pandey, S P

    2005-01-01

    Land application has become a widely applied method for treating wastewater. However, it is not always clear which soil-plant systems should be used, or why. The objectives of our study were to determine if four contrasting soils, from which the pasture is regularly cut and removed, varied in their ability to assimilate nutrients from secondary-treated domestic effluent under high hydraulic loadings, in comparison with unirrigated, fertilized pasture. Grassed intact soil cores (500 mm in diameter by 700 mm in depth) were irrigated (50 mm wk(-1)) with secondary-treated domestic effluent for two years. Soils included a well-drained Allophanic Soil (Typic Hapludand), a poorly drained Gley Soil (Typic Endoaquept), a well-drained Pumice Soil formed from rhyolitic tephra (Typic Udivitrand), and a well-drained Recent Soil formed in a sand dune (Typic Udipsamment). Effluent-irrigated soils received between 746 and 815 kg N ha(-1) and 283 and 331 kg P ha(-1) over two years of irrigation, and unirrigated treatments received 200 kg N ha(-1) and 100 kg P ha(-1) of dissolved inorganic fertilizer over the same period. Applying effluent significantly increased plant uptake of N and P from all soil types. For the effluent-irrigated soils plant N uptake ranged from 186 to 437 kg N ha(-1) yr(-1), while plant P uptake ranged from 40 to 88 kg P ha(-1) yr(-1) for the effluent-irrigated soils. Applying effluent significantly increased N leaching losses from Gley and Recent Soils, and after two years ranged from 17 to 184 kg N ha(-1) depending on soil type. Effluent irrigation only increased P leaching from the Gley Soil. All P leaching losses were less than 49 kg P ha(-1) after two years. The N and P leached from effluent treatments were mainly in organic form (69-87% organic N and 35-65% unreactive P). Greater N and P leaching losses from the irrigated Gley Soil were attributed to preferential flow that reduced contact between the effluent and the soil matrix. Increased N leaching from

  6. Biochar and manure affect calcareous soil and corn silage nutrient concentrations and uptake.

    PubMed

    Lentz, R D; Ippolito, J A

    2012-01-01

    Carbon-rich biochar derived from the pyrolysis of biomass can sequester atmospheric CO, mitigate climate change, and potentially increase crop productivity. However, research is needed to confirm the suitability and sustainability of biochar application to different soils. To an irrigated calcareous soil, we applied stockpiled dairy manure (42 Mg ha dry wt) and hardwood-derived biochar (22.4 Mg ha), singly and in combination with manure, along with a control, yielding four treatments. Nitrogen fertilizer was applied when needed (based on preseason soil test N and crop requirements) in all plots and years, with N mineralized from added manure included in this determination. Available soil nutrients (NH-N; NO-N; Olsen P; and diethylenetriaminepentaacetic acid-extractable K, Mg, Na, Cu, Mn, Zn, and Fe), total C (TC), total N (TN), total organic C (TOC), and pH were evaluated annually, and silage corn nutrient concentration, yield, and uptake were measured over two growing seasons. Biochar treatment resulted in a 1.5-fold increase in available soil Mn and a 1.4-fold increase in TC and TOC, whereas manure produced a 1.2- to 1.7-fold increase in available nutrients (except Fe), compared with controls. In 2009 biochar increased corn silage B concentration but produced no yield increase; in 2010 biochar decreased corn silage TN (33%), S (7%) concentrations, and yield (36%) relative to controls. Manure produced a 1.3-fold increase in corn silage Cu, Mn, S, Mg, K, and TN concentrations and yield compared with the control in 2010. The combined biochar-manure effects were not synergistic except in the case of available soil Mn. In these calcareous soils, biochar did not alter pH or availability of P and cations, as is typically observed for acidic soils. If the second year results are representative, they suggest that biochar applications to calcareous soils may lead to reduced N availability, requiring additional soil N inputs to maintain yield targets.

  7. Mycorrhiza and PGPB modulate maize biomass, nutrient uptake and metabolic pathways in maize grown in mining-impacted soil.

    PubMed

    Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika

    2015-12-01

    Abiotic stress factors including poor nutrient content and heavy metal contamination in soil, can limit plant growth and productivity. The main goal of our study was to evaluate element uptake, biomass and metabolic responses in maize roots growing in mining-impacted soil with the combination of arbuscular mycorrhiza (My) and plant growth promoting bacteria (PGPB/B). Maize plants subjected to PGPB, My and combined treatments showed a significant increase in biomass and uptake of some elements in shoot and root. Metabolite analysis identified 110 compounds that were affected ≥2-fold compared to control, with 69 metabolites upregulated in the My group, 53 metabolites in the My+B group and 47 metabolites in B group. Pathway analysis showed that impact on glyoxylate and dicarboxylate metabolism was common between My and My+B groups, whereas PGPB group showed a unique effect on fatty acid biosynthesis with significant increase in palmitic acid and stearic acid. Differential regulation of some metabolites by mycorrhizal treatment correlated with root biomass while PGPB regulated metabolites correlated with biomass increase in shoot. Overall, the combination of rhizospheric microorganisms used in our study significantly increased maize nutrient uptake and growth relative to control. The changes in metabolic pathways identified during the symbiotic interaction will improve our understanding of mechanisms involved in rhizospheric interactions that are responsible for increased growth and nutrient uptake in crop plants.

  8. Impacts of industrial waste resources on maize (Zea mays L.) growth, yield, nutrients uptake and soil properties.

    PubMed

    Singh, Satnam; Young, Li-Sen; Shen, Fo-Ting; Young, Chiu-Chung

    2014-10-01

    Discharging untreated highly acidic (pH<4.0), organic and nutrients rich monosodium glutamate wastewater (MW), and highly alkaline (pH>10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5±0.1) with PW and lime (treatments represented as MW+PW and MW+Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha(-1). Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear(-1) and 100-kernel weight were higher in MW+Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW+Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW+PW. The MW+PW and MW+Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.

  9. Structure of the trypanosome haptoglobin–hemoglobin receptor and implications for nutrient uptake and innate immunity

    PubMed Central

    Higgins, Matthew K.; Tkachenko, Olga; Brown, Alan; Reed, Jenny; Raper, Jayne; Carrington, Mark

    2013-01-01

    African trypanosomes are protected by a densely packed surface monolayer of variant surface glycoprotein (VSG). A haptoglobin–hemoglobin receptor (HpHbR) within this VSG coat mediates heme acquisition. HpHbR is also exploited by the human host to mediate endocytosis of trypanolytic factor (TLF)1 from serum, contributing to innate immunity. Here, the crystal structure of HpHbR from Trypanosoma congolense has been solved, revealing an elongated three α-helical bundle with a small membrane distal head. To understand the receptor in the context of the VSG layer, the dimensions of Trypanosoma brucei HpHbR and VSG have been determined by small-angle X-ray scattering, revealing the receptor to be more elongated than VSG. It is, therefore, likely that the receptor protrudes above the VSG layer and unlikely that the VSG coat can prevent immunoglobulin binding to the receptor. The HpHb-binding site has been mapped by single-residue mutagenesis and surface plasmon resonance. This site is located where it is readily accessible above the VSG layer. A single HbHpR polymorphism unique to human infective T. brucei gambiense has been shown to be sufficient to reduce binding of both HpHb and TLF1, modulating ligand affinity in a delicate balancing act that allows nutrient acquisition but avoids TLF1 uptake. PMID:23319650

  10. Structure of the trypanosome haptoglobin-hemoglobin receptor and implications for nutrient uptake and innate immunity.

    PubMed

    Higgins, Matthew K; Tkachenko, Olga; Brown, Alan; Reed, Jenny; Raper, Jayne; Carrington, Mark

    2013-01-29

    African trypanosomes are protected by a densely packed surface monolayer of variant surface glycoprotein (VSG). A haptoglobin-hemoglobin receptor (HpHbR) within this VSG coat mediates heme acquisition. HpHbR is also exploited by the human host to mediate endocytosis of trypanolytic factor (TLF)1 from serum, contributing to innate immunity. Here, the crystal structure of HpHbR from Trypanosoma congolense has been solved, revealing an elongated three α-helical bundle with a small membrane distal head. To understand the receptor in the context of the VSG layer, the dimensions of Trypanosoma brucei HpHbR and VSG have been determined by small-angle X-ray scattering, revealing the receptor to be more elongated than VSG. It is, therefore, likely that the receptor protrudes above the VSG layer and unlikely that the VSG coat can prevent immunoglobulin binding to the receptor. The HpHb-binding site has been mapped by single-residue mutagenesis and surface plasmon resonance. This site is located where it is readily accessible above the VSG layer. A single HbHpR polymorphism unique to human infective T. brucei gambiense has been shown to be sufficient to reduce binding of both HpHb and TLF1, modulating ligand affinity in a delicate balancing act that allows nutrient acquisition but avoids TLF1 uptake.

  11. Modeled diversity effects on microbial ecosystem functions of primary production, nutrient uptake, and remineralization.

    PubMed

    Goebel, Nicole L; Edwards, Christopher A; Follows, Michael J; Zehr, Jonathan P

    2014-01-01

    Ecosystem-wide primary productivity generally increases with primary producer diversity, emphasizing the importance of diversity for ecosystem function. However, most studies that demonstrate this positive relationship have focused on terrestrial and aquatic benthic systems, with little attention to the diverse marine pelagic primary producers that play an important role in regulating global climate. Here we show how phytoplankton biodiversity enhances overall marine ecosystem primary productivity and other ecosystem functions using a self-organizing ecosystem model. Diversity manipulation numerical experiments reveal positive, asymptotically saturating relationships between ecosystem-wide phytoplankton diversity and functions of productivity, nutrient uptake, remineralization, and diversity metrics used to identify mechanisms shaping these relationships. Increase in productivity with increasing diversity improves modeled ecosystem stability and model robustness and leads to productivity rates that exceed expected yields primarily through niche complementarity and facilitative interactions between coexisting phytoplankton types; the composition of traits in assemblages determines the magnitude of complementarity and selection effects. While findings based on these aggregate measures of diversity effects parallel those from the majority of experimental outcomes of terrestrial and benthic biodiversity-ecosystem function studies, we combine analyses of community diversity effects and investigations of the underlying interactions among phytoplankton types to demonstrate how an increase in recycled production of non-diatoms through an increase in new production of diatoms drives this diversity-cosystem function response. We demonstrate the important role that facilitation plays in the modeled marine plankton and how this facilitative interaction could amplify future climate-driven changes in ocean ecosystem productivity.

  12. Effect of iron stress on Withania somnifera L.: antioxidant enzyme response and nutrient elemental uptake of in vitro grown plants.

    PubMed

    Rout, Jyoti Ranjan; Behera, Sadhana; Keshari, Nitin; Ram, Shidharth Sankar; Bhar, Subhajit; Chakraborty, Anindita; Sudarshan, Mathummal; Sahoo, Santi Lata

    2015-03-01

    In the present study the response of antioxidant enzyme activities and the level of expression of their corresponding genes on bioaccumulation of iron (Fe) were investigated. In vitro germinated Withania somnifera L. were grown in Murashige and Skoog's liquid medium with increasing concentrations (0, 25, 50, 100 and 200 µM) of FeSO4 for 7 and 14 days. Root and leaf tissues analyzed for catalase (CAT, EC 1.11.1.6), superoxide dismutase (SOD, EC 1.15.1.1) and guaiacol peroxidase (GPX, EC 1.11.1.7), have shown an increase in content with respect to exposure time. Isoforms of CAT, SOD and GPX were separated using non-denaturing polyacrylamide gel electrophoresis and observed that the isoenzymes were greatly affected by higher concentrations of Fe. Reverse transcriptase polymerase chain reaction analysis performed by taking three pairs of genes of CAT (RsCat, Catalase1, Cat1) and SOD (SodCp, TaSOD1.2, MnSOD) to find out the differential expression of antioxidant genes under Fe excess. RsCat from CAT and MnSOD from SOD have exhibited high levels of gene expression under Fe stress, which was consistent with the changes of the activity assayed in solution after 7 days of treatment. Analysis by proton induced X-ray emission exhibited an increasing uptake of Fe in plants by suppressing and expressing of other nutrient elements. The results of the present study suggest that higher concentration of Fe causes disturbance in nutrient balance and induces oxidative stress in plant.

  13. Therapeutic perspectives of epigenetically active nutrients.

    PubMed

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-06-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction.

  14. Therapeutic perspectives of epigenetically active nutrients

    PubMed Central

    Remely, M; Lovrecic, L; de la Garza, A L; Migliore, L; Peterlin, B; Milagro, F I; Martinez, A J; Haslberger, A G

    2015-01-01

    Many nutrients are known for a wide range of activities in prevention and alleviation of various diseases. Recently, their potential role in regulating human health through effects on epigenetics has become evident, although specific mechanisms are still unclear. Thus, nutriepigenetics/nutriepigenomics has emerged as a new and promising field in current epigenetics research in the past few years. In particular, polyphenols, as part of the central dynamic interaction between the genome and the environment with specificity at physiological concentrations, are well known to affect mechanisms underlying human health. This review summarizes the effects of dietary compounds on epigenetic mechanisms in the regulation of gene expression including expression of enzymes and other molecules responsible for drug absorption, distribution, metabolism and excretion in cancer, metabolic syndrome, neurodegenerative disorders and hormonal dysfunction. PMID:25046997

  15. Fluorescence-based measurement of cystine uptake through xCT shows requirement for ROS detoxification in activated lymphocytes.

    PubMed

    Siska, Peter J; Kim, Bumki; Ji, Xiangming; Hoeksema, Megan D; Massion, Pierre P; Beckermann, Kathryn E; Wu, Jianli; Chi, Jen-Tsan; Hong, Jiyong; Rathmell, Jeffrey C

    2016-11-01

    T and B lymphocytes undergo metabolic re-programming upon activation that is essential to allow bioenergetics, cell survival, and intermediates for cell proliferation and function. To support changes in the activity of signaling pathways and to provide sufficient and necessary intracellular metabolites, uptake of extracellular nutrients increases sharply with metabolic re-programming. One result of increased metabolic activity can be reactive oxygen species (ROS), which can be toxic when accumulated in excess. Uptake of cystine allows accumulation of cysteine that is necessary for glutathione synthesis and ROS detoxification. Cystine uptake is required for T cell activation and function but measurements based on radioactive labeling do not allow analysis on single cell level. Here we show the critical role for cystine uptake in T cells using a method for measurement of cystine uptake using a novel CystineFITC probe. T cell receptor stimulation lead to upregulation of the cystine transporter xCT (SLC7a11) and increased cystine uptake in CD4+ and CD8+ human T cells. Similarly, lipopolysaccharide stimulation increased cystine uptake in human B cells. The CystineFITC probe was not toxic and could be metabolized to prevent cystine starvation induced cell death. Furthermore, blockade of xCT or competition with natural cystine decreased uptake of CystineFITC. CystineFITC is thus a versatile tool that allows measurement of cystine uptake on single cell level and shows the critical role for cystine uptake for T cell ROS regulation and activation.

  16. Calcium uptake and bioelectrical activity of denervated and myotonic muscle

    PubMed Central

    Radu, H.; Gödri, I.; Albu, E.; Radu, A.; Robu, R.

    1970-01-01

    Calcium uptake on muscle microsomal fraction has been investigated in connection with bioelectrical activity in some muscle diseases. The findings showed a significant increase of calcium uptake in denervated muscle, which exhibited spontaneous bioelectrical activity (fibrillations). In myotonias, a low calcium uptake was peculiar to Steinert's disease but not to myotonia congenita. In other muscle diseases, such as progressive muscular dystrophy (Duchenne's type) or Charcot-Marie-Tooth's disease, the ability of muscle microsomal fraction to bind calcium was not changed. Starting with the key role of calcium in excitation-contraction coupling, the implications of calcium uptake disturbances in muscle electrogenesis are discussed. Images PMID:5431720

  17. Complementary nutrient effects of separately collected human faeces and urine on the yield and nutrient uptake of spinach (Spinacia oleracea).

    PubMed

    Kutu, Funso R; Muchaonyerwa, Pardon; Mnkeni, Pearson N S

    2011-05-01

    A glasshouse experiment was conducted to evaluate the combined use of separately collected human faeces and urine as fertilizer for spinach (Spinacia oleracea) production. Seven human faeces N : urine N combinations (1 : 7 to 7 : 1) each supplying 200 kg N ha(-1) were evaluated along with sole human faeces, sole urine, inorganic fertilizer and an unamended control. Complementary application of the two resources, human faeces and urine, increased fresh and dry matter yields only in treatments having high proportions of urine. Nitrogen uptake followed the same trend but the opposite trend occurred for P uptake indicating that urine was a better source of N whereas human faeces were the better source of P. Potassium uptake was not influenced by the two resources. The minimal improvement observed in the fertilizer value of human faeces when co-applied with urine suggested that co-application of the two resources may not give an added yield advantage when compared with sole human faeces.

  18. Ammonium and nitrate uptake lengths in a small forested stream determined by {sup 15}N tracer and short-term nutrient enrichment experiments

    SciTech Connect

    Mulholland, P.J.; Tank, J.L.; Sanzone, D.M.; Webster, J.R.; Wollheim, W.; Peterson, B.J.; Meyer, J.L.

    1998-11-01

    Nutrient cycling is an important characteristic of all ecosystems, including streams. Nutrients often limit the growth rates of stream algae and heterotrophic microbes and the decomposition rate of allochthonous organic matter. Nutrient uptake (S{sub W}), defined as the mean distance traveled by a nutrient atom dissolved in stream water before uptake by biota is often used as an index of nutrient cycling in streams. It is often overlooked, however, that S{sub W} is not a measure of nutrient uptake rate per se, but rather a measure of the efficiency with which a stream utilizes the available nutrient supply. The ideal method for measuring S{sub W} involves short-term addition of a nutrient tracer. Regulatory constraints often preclude use of nutrient radiotracers in field studies and methodological difficulties and high analytical costs have previously hindered the use of stable isotope nutrient tracers (e.g., {sup 15}N). Short-term nutrient enrichments are an alternative to nutrient tracer additions for measuring S{sub W}.

  19. Impact of variable bed morphology on transient storage, hyporhic exchange and nutrient uptake in a field-scale flume

    NASA Astrophysics Data System (ADS)

    Orr, C. H.; Clark, J. J.; Wilcock, P. R.; Finlay, J. C.; Doyle, M. W.

    2006-12-01

    As part of an ongoing, multidisciplinary experimental effort coordinated by the National Center for Earth-surface Dynamics we investigated reach-scale interactions between, bed morphology, transient storage, nutrient cycling in a field-scale flume supplied with water from the Mississippi River. A combination of conservative salt tracer and soluble reactive phosphorous and nitrate additions was used to study the effects on these parameters of two bed morphologies (plane bed and alternate bar) and two sediment mixtures (clean gravel and sandy gravel) to determine how differences in sediment size and between plane-bed and laterally variable morphologies influence spatial heterogeneity in transport and uptake of nutrients. The goal was to partitioning reach-scale transient storage values between surface storage and hyporheic flow, determine how these values and their relative importance changed as we varied bed texture (or permeability) and added or removed surface features, and to then measure uptake of biologically available nitrogen and phosphorus individually and together along these surface and subsurface flow paths. In a final phase of the experiment, lights were added to the flume to determine how benthic algal abundance may change bed permeability and solute exchange with the bed as well as nutrient uptake rates. Initial results show that while mean water residence time varied by a factor of 2 across treatments (14 - 30 min) phosphorus uptake rates varied widely (5.5-2500 μg * m-2 * min-1 and the addition of light had a stronger impact on uptake rates than changes in geomorphic form.

  20. Nutrient Uptake by Microorganisms according to Kinetic Parameters from Theory as Related to Cytoarchitecture

    PubMed Central

    Button, D. K.

    1998-01-01

    The abilities of organisms to sequester substrate are described by the two kinetic constants specific affinity, a°, and maximal velocity Vmax. Specific affinity is derived from the frequency of substrate-molecule collisions with permease sites on the cell surface at subsaturating concentrations of substrates. Vmax is derived from the number of permeases and the effective residence time, τ, of the transported molecule on the permease. The results may be analyzed with affinity plots (v/S versus v, where v is the rate of substrate uptake), which extrapolate to the specific affinity and are usually concave up. A third derived parameter, the affinity constant KA, is similar to KM but is compared to the specific affinity rather than Vmax  and is defined as the concentration of substrate necessary to reduce the specific affinity by half. It can be determined in the absence of a maximal velocity measurement and is equal to the Michaelis constant for a system with hyperbolic kinetics. Both are taken as a measure of τ, with departure of KM from KA being affected by permease/enzyme ratios. Compilation of kinetic data indicates a 108-fold range in specific affinities and a smaller (103-fold) range in Vmax values. Data suggest that both specific affinities and maximal velocities can be underestimated by protocols which interrupt nutrient flow prior to kinetic analysis. A previously reported inverse relationship between specific affinity and saturation constants was confirmed. Comparisons of affinities with ambient concentrations of substrates indicated that only the largest a°S values are compatible with growth in natural systems. PMID:9729603

  1. Uptake and partitioning of nutrients in blackberry and raspberry and evaluating plant nutrient status for accurate assessment of fertilizer requirements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raspberry and blackberry plantings have relatively low nutrient requirements compared to many other perennial fruit crops. Annual total N accumulation in the aboveground plant ranged from 69-122 kg/ha and 37-44 kg/ha in field-grown red raspberry and blackberry. Primocanes rely primarily on fertilize...

  2. Uptake and partitioning of nutrients in blackberry and raspberry and evaluating plant nutrient status for accurate assessment of fertilizer requirements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raspberry and blackberry plantings have a relatively low nutrient requirement compared to many other perennial fruit crops. Annual total N accumulation ranged from 62-110 lb/a in red raspberry and 33-39 lb/a in blackberry. Primocanes rely primarily on fertilizer N for growth, whereas floricane growt...

  3. Complementarity in root architecture for nutrient uptake in ancient maize/bean and maize/bean/squash polycultures

    PubMed Central

    Postma, Johannes A.; Lynch, Jonathan P.

    2012-01-01

    Background and Aims During their domestication, maize, bean and squash evolved in polycultures grown by small-scale farmers in the Americas. Polycultures often overyield on low-fertility soils, which are a primary production constraint in low-input agriculture. We hypothesized that root architectural differences among these crops causes niche complementarity and thereby greater nutrient acquisition than corresponding monocultures. Methods A functional–structural plant model, SimRoot, was used to simulate the first 40 d of growth of these crops in monoculture and polyculture and to determine the effects of root competition on nutrient uptake and biomass production of each plant on low-nitrogen, -phosphorus and -potassium soils. Key Results Squash, the earliest domesticated crop, was most sensitive to low soil fertility, while bean, the most recently domesticated crop, was least sensitive to low soil fertility. Nitrate uptake and biomass production were up to 7 % greater in the polycultures than in the monocultures, but only when root architecture was taken into account. Enhanced nitrogen capture in polycultures was independent of nitrogen fixation by bean. Root competition had negligible effects on phosphorus or potassium uptake or biomass production. Conclusions We conclude that spatial niche differentiation caused by differences in root architecture allows polycultures to overyield when plants are competing for mobile soil resources. However, direct competition for immobile resources might be negligible in agricultural systems. Interspecies root spacing may also be too large to allow maize to benefit from root exudates of bean or squash. Above-ground competition for light, however, may have strong feedbacks on root foraging for immobile nutrients, which may increase cereal growth more than it will decrease the growth of the other crops. We note that the order of domestication of crops correlates with increasing nutrient efficiency, rather than production

  4. Effect of organic selenium supplementation on growth, Se uptake, and nutrient utilization in guinea pigs.

    PubMed

    Chaudhary, Mahima; Garg, Anil Kumar; Mittal, Ganesh Kumar; Mudgal, Vishal

    2010-02-01

    Forty weaned male guinea pigs (Cavia porcellus) of 152.6 +/- 7.96 g mean body weight were divided into four equal groups and fed a common basal diet comprised of 25% ground cowpea (Vigna unguiculata) hay, 30% ground maize (Zea mays) grain, 22% ground gram (Cicer arietinum) grain, 9.5% deoiled rice (Oryza sativa) bran, 6% soybean (Glycine max) meal, 6% fish meal, 1.5% mineral mixture (without Se), and ascorbic acid at 200 mg/kg to meet their nutrient requirements along with 0, 0.1, 0.2, and 0.3 ppm of organic selenium (Se) in groups I, II, III, and IV, respectively. Experimental feeding lasted for a period of 10 weeks, during which, daily feed intake and weekly body weights were recorded. Intake and digestibility of dry matter, organic matter, ether extract, crude fiber, and nitrogen-free extract as well as uptake of calcium and phosphorus were similar (P > 0.05) among the four groups. Feed:gain ratio was also similar (P > 0.05) in the four groups. However, digestibility of crude protein was significantly (P < 0.001) higher in group II supplemented with 0.1 ppm organic Se as compared to other three group. Intake and absorption of Se was significantly (P < 0.001) higher in all the Se supplemented groups as compared to control group. Average daily gain (ADG) was significantly (P < 0.05) higher in group II (3.16 g/day) and III (3.38 g/day) as compared to group I (2.88 g/day). However, ADG in group IV (supplemented 0.3 ppm organic Se) was significantly (P < 0.05) lower (2.83 g/day) than group II and III, but comparable (P > 0.05) to group I. Findings of the present experiment suggests that Se requirements of guinea pigs are > or =0.2 ppm, as supplementation of 0.1 ppm organic Se in the diet (having 0.1 ppm Se) not only enhanced their growth rate but also improved the protein utilization.

  5. An essential dual-function complex mediates erythrocyte invasion and channel-mediated nutrient uptake in malaria parasites

    PubMed Central

    Ito, Daisuke; Schureck, Marc A; Desai, Sanjay A

    2017-01-01

    Malaria parasites evade immune detection by growth and replication within erythrocytes. After erythrocyte invasion, the intracellular pathogen must increase host cell uptake of nutrients from plasma. Here, we report that the parasite-encoded RhopH complex contributes to both invasion and channel-mediated nutrient uptake. As rhoph2 and rhoph3 gene knockouts were not viable in the human P. falciparum pathogen, we used conditional knockdowns to determine that the encoded proteins are essential and to identify their stage-specific functions. We exclude presumed roles for RhopH2 and CLAG3 in erythrocyte invasion but implicate a RhopH3 contribution either through ligand-receptor interactions or subsequent parasite internalization. These proteins then traffic via an export translocon to the host membrane, where they form a nutrient channel. Knockdown of either RhopH2 or RhopH3 disrupts the entire complex, interfering with organellar targeting and subsequent trafficking. Therapies targeting this complex should attack the pathogen at two critical points in its cycle. DOI: http://dx.doi.org/10.7554/eLife.23485.001 PMID:28221136

  6. Silicon uptake by sponges: a twist to understanding nutrient cycling on continental margins.

    PubMed

    Maldonado, Manuel; Navarro, Laura; Grasa, Ana; Gonzalez, Alicia; Vaquerizo, Isabel

    2011-01-01

    About 75% of extant sponge species use dissolved silicon (DSi) to build a siliceous skeleton. We show that silicon (Si) uptake by sublittoral Axinella demosponges follows an enzymatic kinetics. Interestingly, maximum uptake efficiency occurs at experimental DSi concentrations two orders of magnitude higher than those in the sponge habitats, being unachievable in coastal waters of modern oceans. Such uptake performance appears to be rooted in a former condition suitable to operate at the seemingly high DSi values characterizing the pre-Tertiary (>65 mya) habitats where this sponge lineage diversified. Persistence of ancestral uptake systems causes sponges to be outcompeted by the more efficient uptake of diatoms at the low ambient DSi levels characterizing Recent oceans. Yet, we show that sublittoral sponges consume substantial coastal DSi (0.01-0.90 mmol Si m(-2) day(-1)) at the expenses of the primary-production circuit. Neglect of that consumption hampers accurate understanding of Si cycling on continental margins.

  7. Harmful algal blooms and eutrophication: "strategies" for nutrient uptake and growth outside the Redfield comfort zone

    NASA Astrophysics Data System (ADS)

    Glibert, Patricia M.; Burkholder, Joann M.

    2011-07-01

    While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.

  8. Chromium phytotoxicity in radish (Raphanus sativus): effects on metabolism and nutrient uptake.

    PubMed

    Tiwari, K K; Singh, N K; Rai, U N

    2013-09-01

    In the present investigation, chromium (VI) induced toxicity on metabolic activity and translocations of nutrients in radish were evaluated under controlled glass house conditions. Chromium was found to induce toxicity and significantly affect plant growth and metabolic activity. Excess of chromium (0.4 mM) caused a decrease in the concentration of iron in leaves (from 134.3 to 71.9 μg g(-1) dw) and significant translocation of sulphur, phosphorus and zinc. Translocation of manganese, copper and boron were less affected from root to stem. After 15 days of Cr exposure, maximum accumulation of Cr was found in roots (327.6 μg g(-1) dw) followed by stems (186.8 μg g(-1) dw) and leaves (116.7 μg g(-1) dw) at 0.4 mM Cr concentration. Therefore, Cr may affect negatively not only production, but also the nutritive quality of the radish; likewise, higher Cr content may cause health hazards for humans.

  9. 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.

  10. Compost and crude humic substances produced from selected wastes and their effects on Zea mays L. nutrient uptake and growth.

    PubMed

    Palanivell, Perumal; Susilawati, Kasim; Ahmed, Osumanu Haruna; Majid, Nik Muhamad

    2013-01-01

    Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA), crude fulvic acids (CFA), crude humin (CH), soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants' diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation.

  11. Compost and Crude Humic Substances Produced from Selected Wastes and Their Effects on Zea mays L. Nutrient Uptake and Growth

    PubMed Central

    Palanivell, Perumal; Susilawati, Kasim; Ahmed, Osumanu Haruna; Majid, Nik Muhamad

    2013-01-01

    Production of agriculture and timber commodities leads generation of enormous quantity of wastes. Improper disposal of these agroindustrial wastes pollutes the environment. This problem could be reduced by adding value to them. Therefore, a study was carried out to analyse and compare the nutrients content of RS, RH, SD, and EFB of composts and crude humic substances; furthermore, their effect on growth, dry matter production, and nutrient uptake for Zea mays L., and selected soil chemical properties were evaluated. Standard procedures were used to analyze humic acids (HA), crude fulvic acids (CFA), crude humin (CH), soil, dry matter production and nutrient uptake. Sawdust and RS compost matured at 42 and 47 days, respectively, while RH and EFB composts were less matured at 49th day of composting. Rice straw compost had higher ash, N, P, CEC, HA, K, and Fe contents with lower organic matter, total organic carbon, and C/N and C/P ratios. The HA of sawdust compost showed higher carbon, carboxylic, K, and Ca contents compared to those of RS, RH, and EFB. Crude FA of RS compost showed highest pH, total K, Ca, Mg, and Na contents. Crude humin from RS compost had higher contents of ash, N, P, and CEC. Rice straw was superior in compost, CFA, and CH, while sawdust compost was superior in HA. Application of sawdust compost significantly increased maize plants' diameter, height, dry matter production, N, P, and cations uptake. It also reduced N, P, and K based chemical fertilizer use by 90%. Application of CH and the composts evaluated in this study could be used as an alternative for chemical fertilizers in maize cultivation. PMID:24319353

  12. Comparable light stimulation of organic nutrient uptake by SAR11 and Prochlorococcus in the North Atlantic subtropical gyre.

    PubMed

    Gómez-Pereira, Paola R; Hartmann, Manuela; Grob, Carolina; Tarran, Glen A; Martin, Adrian P; Fuchs, Bernhard M; Scanlan, David J; Zubkov, Mikhail V

    2013-03-01

    Subtropical oceanic gyres are the most extensive biomes on Earth where SAR11 and Prochlorococcus bacterioplankton numerically dominate the surface waters depleted in inorganic macronutrients as well as in dissolved organic matter. In such nutrient poor conditions bacterioplankton could become photoheterotrophic, that is, potentially enhance uptake of scarce organic molecules using the available solar radiation to energise appropriate transport systems. Here, we assessed the photoheterotrophy of the key microbial taxa in the North Atlantic oligotrophic gyre and adjacent regions using (33)P-ATP, (3)H-ATP and (35)S-methionine tracers. Light-stimulated uptake of these substrates was assessed in two dominant bacterioplankton groups discriminated by flow cytometric sorting of tracer-labelled cells and identified using catalysed reporter deposition fluorescence in situ hybridisation. One group of cells, encompassing 48% of all bacterioplankton, were identified as members of the SAR11 clade, whereas the other group (24% of all bacterioplankton) was Prochlorococcus. When exposed to light, SAR11 cells took 31% more ATP and 32% more methionine, whereas the Prochlorococcus cells took 33% more ATP and 34% more methionine. Other bacterioplankton did not demonstrate light stimulation. Thus, the SAR11 and Prochlorococcus groups, with distinctly different light-harvesting mechanisms, used light equally to enhance, by approximately one-third, the uptake of different types of organic molecules. Our findings indicate the significance of light-driven uptake of essential organic nutrients by the dominant bacterioplankton groups in the surface waters of one of the less productive, vast regions of the world's oceans-the oligotrophic North Atlantic subtropical gyre.

  13. Plant aquaporins: new perspectives on water and nutrient uptake in saline environment.

    PubMed

    del Martínez-Ballesta, M C; Silva, C; López-Berenguer, C; Cabañero, F J; Carvajal, M

    2006-09-01

    The mechanisms of salt stress and tolerance have been targets for genetic engineering, focusing on ion transport and compartmentation, synthesis of compatible solutes (osmolytes and osmoprotectants) and oxidative protection. In this review, we consider the integrated response to salinity with respect to water uptake, involving aquaporin functionality. Therefore, we have concentrated on how salinity can be alleviated, in part, if a perfect knowledge of water uptake and transport for each particular crop and set of conditions is available.

  14. Growth, morphology, ammonium uptake and nutrient allocation of Myriophyllum brasiliense Cambess. under high NH₄⁺ concentrations.

    PubMed

    Saunkaew, Piyanart; Wangpakapattanawong, Prasit; Jampeetong, Arunothai

    2011-11-01

    The effects of high NH(4)(+) concentration on growth, morphology, NH(4) (+) uptake and nutrient allocation of Myriophyllum brasiliense were investigated in hydroponic culture. The plants were grown under greenhouse conditions for 4 weeks using four levels of NH(4)(+) concentration: 1, 5, 10 and 15 mM. M. brasiliense grew well with a relative growth rate of c.0.03 day(-1) at NH(4)(+) concentration up to 5 mM. At the higher NH(4)(+) concentrations the growth of the plants was stunted and the plants had short roots and few new buds, especially when grown in 15 mM NH(4)(+) where the submerged leaves were lost and there were rotten roots and submerged stems. To avoid NH(4)(+) toxicity, the plants may have a mechanism to prevent cytoplasmic NH(4)(+) accumulation in plant cells. The net uptake of NH(4)(+) significantly decreased and the total N significantly increased in the plants treated with 10 and 15 mM NH(4)(+), respectively. The plant may employ NH(4)(+) assimilation and extrusion as a mechanism to compensate for the high NH(4)(+) concentrations. However, the plants may show nutrient deficiency symptoms, especially K deficiency symptoms, after they were exposed to NH(4)(+) concentration higher than 10 mM. The present study provides a basic ecophysiology of M. brasiliense that it can grow in NH(4)(+) enriched water up to concentrations as high as 5 mM.

  15. 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.

  16. Enhancement of growth and nutrient uptake of rapeseed (Brassica napus L.) by applying mineral nutrients and biofertilizers.

    PubMed

    Yasari, Esmaeil; Azadgoleh, M A Esmaeili; Mozafari, Saedeh; Alashti, Mahsa Rafati

    2009-01-15

    For investigating the effect of chemical fertilizer as well as biofertilizers on seed yield and quality i.e. oil, protein and nutrients concentration of rapeseed (Brassica napus L.), a split-plot fertilizers application experimental design in 4 replications was carried out during the 2005-2006 growing season, at the Gharakheil Agricultural Research Station in the Mazandaran province of Iran. Rapeseed was grown as a second crop in rotation after rice. Biofertilizers treatments were two different levels: control (no seed inoculation) and seeds inoculation with a combination of Azotobacter chroococcum and Azosprillum brasilense and Azosprillum lipoferum, as main plot and chemical fertilizers comprised N, P, K and their combinations, NPKS and NPK Zn as sub plots. The maximum value of seed yield obtained at (BF+NPK Zn) 3421.2 kg h(-1) corresponding to 244.5 pods per plant and maximum concentration of Zn in leaves as well as seeds. The highest weight of 1000 seeds (4.45 g) happened to obtain at (BF+NPK S) which coinciding with the maximum K levels in leaves. The highest number of branches was obtained at (BF+NPK Zn) with 4.43 branches per plant i.e., 46.2% increase over the control. The maximum value of rapeseed oil content 47.73% obtained at T16 (BF+NK) but maximum protein concentration of seed obtained at T12 (BF+N). Overall the results indicated that inoculation resulted in increase in seeds yield (21.17%), number of pods per plant (16.05%), number of branches (11.78%), weight of 1000 grain (2.92%), oil content of seeds (1.73%) and protein (3.91%) but decrease (-0.24%) in number of seeds per pods comparing to non-Biofertilizers treatments. Irrespective to the treatments, results showed that application of Biofertilizers coincided with 3.86, 0.82, 2.25, 0.75 and 0.91% increase in concentrations of N, P, K, S and Zn in the seeds over the non-Biofertilizers treatments.

  17. 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.

  18. Vigorous Root Growth Is a Better Indicator of Early Nutrient Uptake than Root Hair Traits in Spring Wheat Grown under Low Fertility

    PubMed Central

    Wang, Yaosheng; Thorup-Kristensen, Kristian; Jensen, Lars Stoumann; Magid, Jakob

    2016-01-01

    A number of root and root hair traits have been proposed as important for nutrient acquisition. However, there is still a need for knowledge on which traits are most important in determining macro- and micronutrient uptake at low soil fertility. This study investigated the variations in root growth vigor and root hair length (RHL) and density (RHD) among spring wheat genotypes and their relationship to nutrient concentrations and uptake during early growth. Six spring wheat genotypes were grown in a soil with low nutrient availability. The root and root hair traits as well as the concentration and content of macro- and micronutrients were identified. A significant genetic variability in root and root hair traits as well as nutrient uptake was found. Fast and early root proliferation and long and dense root hairs enhanced uptake of macro- and micronutrients under low soil nutrient availability. Vigorous root growth, however, was a better indicator of early nutrient acquisition than RHL and RHD. Vigorous root growth and long and dense root hairs ensured efficient acquisition of macro- and micronutrients during early growth and a high root length to shoot dry matter ratio favored high macronutrient concentrations in the shoots, which is assumed to be important for later plant development. PMID:27379145

  19. Landspreading MSW compost in Wisconsin: Effect on corn yield, nutrient and metal uptake, and soil nitrate-N

    SciTech Connect

    Wolkowski, R.P.

    1995-12-31

    Studies were conducted at several Wisconsin locations from 1991-1994 to determine the effect of municipal solid waste (MSW) compost on corn (Zea mays L.) growth, nutrient and metal uptake, and soil nitrate-N content. Composts of varying maturities were applied at rates ranging between 0 and 56 t/a (dry matter basis), depending on year and location. Commercial fertilizers were applied to separate plots to determine the extent of nutrient availability from the compost. All treatments were applied in the spring and incorporated prior to planting corn. Mature compost always increased growth and yield above the untreated control, but the highest yields were found where recommended fertilizer was applied. Immature compost suppressed growth and reduced yield. Compost generally increased the levels of plant nutrients in the whole-plant tissue and grain. While compost did increase the concentration of some metals in the whole-plant tissue, these levels were found to be within the range expected for corn. Compost did not affect metal concentration in the grain. Soil nitrate-N was higher throughout most of the growing season in treatments receiving recommended N fertilizer.

  20. Corn grain and nutrient uptake response to different swine manure application methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmers are looking for better management practices to enhance production and reduce negative environmental impact from nitrogen (N) fertilizer application since N is one of the most important and costly nutrient inputs for crop production. In this field experiment pre-plant swine effluent applicati...

  1. NUTRIENT UPTAKE AND COMMUNITY METABOLISM IN STREAMS DRAINING HARVESTED AND OLD GROWTH WATERSHEDS: A PRELIMINARY ASSESSMENT

    EPA Science Inventory

    The effect of timber harvesting on streams is assessed using two measures of ecosystem function: nutrient ad community metabolism. This research is being conducted in streams of the southern Appalachian Mountains of North Carolina, the Ouachita Mountains of Arkansas, the Cascad...

  2. Biotite weathering and nutrient uptake by ectomycorrhizal fungus, Suillus tomentosus, in liquid-culture experiments

    NASA Astrophysics Data System (ADS)

    Balogh-Brunstad, Zsuzsanna; Kent Keller, C.; Thomas Dickinson, J.; Stevens, Forrest; Li, C. Y.; Bormann, Bernard T.

    2008-06-01

    Ectomycorrhiza-forming fungi (EMF) alter the nutrient-acquisition capabilities of vascular plants, and may play an important role in mineral weathering and the partitioning of products of weathering in soils under nutrient-limited conditions. In this study, we isolated the weathering function of Suillus tomentosus in liquid-cultures with biotite micas incubated at room temperature. We hypothesized that the fungus would accelerate weathering by hyphal attachment to biotite surfaces and transmission of nutrient cations via direct exchange into the fungal biomass. We combined a mass-balance approach with scanning electron microscopy (SEM) and atomic force microscopy (AFM) to estimate weathering rates and study dissolution features on biotite surfaces. Weathering of biotite flakes was about 2-3 orders of magnitude faster in shaken liquid-cultures with fungus compared to shaken controls without fungus, but with added inorganic acids. Adding fungus in nonshaken cultures caused a higher dissolution rate than in inorganic pH controls without fungus, but it was not significantly faster than organic pH controls without fungus. The K +, Mg 2+ and Fe 2+ from biotite were preferentially partitioned into fungal biomass in the shaken cultures, while in the nonshaken cultures, K + and Mg 2+ was lost from biomass and Fe 2+ bioaccumulated much less. Fungal hyphae attached to biotite surfaces, but no significant surface changes were detected by SEM. When cultures were shaken, the AFM images of basal planes appeared to be rougher and had abundant dissolution channels, but such channel development was minor in nonshaken conditions. Even under shaken conditions the channels only accounted for only 1/100 of the total dissolution rate of 2.7 × 10 -10 mol of biotite m -2 s -1. The results suggest that fungal weathering predominantly occurred not by attachment and direct transfer of nutrients via hyphae, but because of the acidification of the bulk liquid by organic acids, fungal

  3. Water uptake and nutrient concentrations under a floodplain oak savanna during a non-flood period, lower Cedar River, Iowa

    USGS Publications Warehouse

    Schilling, K.E.; Jacobson, P.

    2009-01-01

    Floodplains during non-flood periods are less well documented than when flooding occurs, but non-flood periods offer opportunities to investigate vegetation controls on water and nutrient cycling. In this study, we characterized water uptake and nutrient concentration patterns from 2005 to 2007 under an oak savanna located on the floodplain of the Cedar River in Muscatine County, Iowa. The water table ranged from 0.5 to 2.5 m below ground surface and fluctuated in response to stream stage, plant water demand and rainfall inputs. Applying the White method to diurnal water table fluctuations, daily ET from groundwater averaged more than 3.5 mm/day in June and July and approximately 2 mm/day in May and August. Total annual ET averaged 404 mm for a growing season from mid-May to mid-October. Savanna groundwater concentrations of nitrate-N, ammonium-N, and phosphate-P were very low (mean <0.18, <0.14, <0.08 mg/l, respectively), whereas DOC concentrations were high (7.1 mg/l). Low concentrations of N and P were in contrast to high nutrient concentrations in the nearby Cedar River, where N and P averaged 7.5 mg/ l and 0.13, respectively. In regions dominated by intensive agriculture, study results document valuable ecosystem services for native floodplain ecosystems in reducing watershed-scale nutrient losses and providing an oasis for biological complexity. Improved understanding of the environmental conditions of regionally significant habitats, including major controls on water table elevations and water quality, offers promise for better management aimed at preserving the ecology of these important habitats. Copyright ?? 2009 John Wiley & Sons, Ltd.

  4. Dynamic sinking behaviour in marine phytoplankton: rapid changes in buoyancy may aid in nutrient uptake.

    PubMed

    Gemmell, Brad J; Oh, Genesok; Buskey, Edward J; Villareal, Tracy A

    2016-10-12

    Phytoplankton sinking is an important property that can determine community composition in the photic zone and material loss to the deep ocean. To date, studies of diatom suspension have relied on bulk measurements with assumptions that bulk rates adequately capture the essential characteristics of diatom sinking. However, recent work has illustrated that individual diatom sinking rates vary considerably from the mean bulk rate. In this study, we apply high-resolution optical techniques, individual-based observations of diatom sinking and a recently developed method of flow visualization around freely sinking cells. The results show that in both field samples and laboratory cultures, some large species of centric diatoms are capable of a novel behaviour, whereby cells undergo bursts of rapid sinking that alternate with near-zero sinking rates on the timescales of seconds. We also demonstrate that this behaviour is under direct metabolic control of the cell. We discuss these results in the context of implications for nutrient flux to the cell surface. While nutrient flux in large diatoms increases during fast sinking, current mass transport models cannot incorporate the unsteady sinking behaviour observed in this study. However, large diatoms appear capable of benefiting from the enhanced nutrient flux to their surface during rapid sinking even during brief intervening periods of near-zero sinking rates.

  5. Active Sulforhodamine 101 Uptake into Hippocampal Astrocytes

    PubMed Central

    Schnell, Christian; Hagos, Yohannes; Hülsmann, Swen

    2012-01-01

    Sulforhodamine 101 (SR101) is widely used as a marker of astrocytes. In this study we investigated labeling of astrocytes by SR101 in acute slices from the ventrolateral medulla and the hippocampus of transgenic mice expressing EGFP under the control of the astrocyte-specific human GFAP promoter. While SR101 efficiently and specifically labeled EGFP-expressing astrocytes in hippocampus, we found that the same staining procedure failed to label astrocytes efficiently in the ventrolateral medulla. Although carbenoxolone is able to decrease the SR101-labeling of astrocytes in the hippocampus, it is unlikely that SR101 is taken up via gap-junction hemichannels because mefloquine, a blocker for pannexin and connexin hemichannels, was unable to prevent SR101-labeling of hippocampal astrocytes. However, SR101-labeling of the hippocampal astrocytes was significantly reduced by substrates of organic anion transport polypeptides, including estron-3-sulfate and dehydroepiandrosterone sulfate, suggesting that SR101 is actively transported into hippocampal astrocytes. PMID:23189143

  6. Microbial dynamics and enzyme activities in tropical Andosols depending on land use and nutrient inputs

    NASA Astrophysics Data System (ADS)

    Mganga, Kevin; Razavi, Bahar; Kuzyakov, Yakov

    2015-04-01

    Microbial decomposition of soil organic matter is mediated by enzymes and is a key source of terrestrial CO2 emissions. Microbial and enzyme activities are necessary to understand soil biochemical functioning and identify changes in soil quality. However, little is known about land use and nutrients availability effects on enzyme activities and microbial processes, especially in tropical soils of Africa. This study was conducted to examine how microbial and enzyme activities differ between different land uses and nutrient availability. As Andosols of Mt. Kilimanjaro are limited by nutrient concentrations, we hypothesize that N and P additions will stimulate enzyme activity. N and P were added to soil samples (0-20 cm) representing common land use types in East Africa: (1) savannah, (2) maize fields, (3) lower montane forest, (4) coffee plantation, (5) grasslands and (6) traditional Chagga homegardens. Total CO2 efflux from soil, microbial biomass and activities of β-glucosidase, cellobiohydrolase, chitinase and phosphatase involved in C, N and P cycling, respectively was monitored for 60 days. Total CO2 production, microbial biomass and enzyme activities varied in the order forest soils > grassland soils > arable soils. Increased β-glucosidase and cellobiohydrolase activities after N addition of grassland soils suggest that microorganisms increased N uptake and utilization to produce C-acquiring enzymes. Low N concentration in all soils inhibited chitinase activity. Depending on land use, N and P addition had an inhibitory or neutral effect on phosphatase activity. We attribute this to the high P retention of Andosols and low impact of N and P on the labile P fractions. Enhanced CO2 production after P addition suggests that increased P availability could stimulate soil organic matter biodegradation in Andosols. In conclusion, land use and nutrients influenced soil enzyme activities and microbial dynamics and demonstrated the decline in soil quality after landuse

  7. Nutrient uptake by agricultural crops from biochar-amended soils: results from two field experiments in Austria

    NASA Astrophysics Data System (ADS)

    Karer, Jasmin; Zehetner, Franz; Kloss, Stefanie; Wimmer, Bernhard; Soja, Gerhard

    2013-04-01

    The use of biochar as soil amendment is considered as a promising agricultural soil management technique, combining carbon sequestration and soil fertility improvements. These expectations are largely founded on positive experiences with biochar applications to impoverished or degraded tropical soils. The validity of these results for soils in temperate climates needs confirmation from field experiments with typical soils representative for intensive agricultural production areas. Frequently biochar is mixed with other organic additives like compost. As these two materials interact with each other and each one may vary considerably in its basic characteristics, it is difficult to attribute the effects of the combined additive to one of its components and to a specific physico-chemical parameter. Therefore investigations of the amendment efficacy require the study of the pure components to characterize their specific behavior in soil. This is especially important for adsorption behavior of biochar for macro- and micronutrients because in soil there are multiple nutrient sinks that compete with plant roots for vital elements. Therefore this contribution presents results from a field amendment study with pure biochar that had the objective to characterize the macro- and microelement uptake of crops from different soils in two typical Austrian areas of agricultural production. At two locations in North and South-East Austria, two identical field experiments on different soils (Chernozem and Cambisol) were installed in 2011 with varying biochar additions (0, 30 and 90 t/ha) and two nitrogen levels. The biochar was a product from slow pyrolysis of wood (SC Romchar SRL). During the installation of the experiments, the biochar fraction of <2 mm was mixed with surface soil to a depth of 15 cm in plots of 33 m2 each (n=4). Barley (at the Chernozem soil) and maize (at the Cambisol) were cultivated according to standard agricultural practices. The highest crop yields at both

  8. Olivine weathering in soil, and its effects on growth and nutrient uptake in Ryegrass (Lolium perenne L.): a pot experiment.

    PubMed

    ten Berge, Hein F M; van der Meer, Hugo G; Steenhuizen, Johan W; Goedhart, Paul W; Knops, Pol; Verhagen, Jan

    2012-01-01

    Mineral carbonation of basic silicate minerals regulates atmospheric CO(2) on geological time scales by locking up carbon. Mining and spreading onto the earth's surface of fast-weathering silicates, such as olivine, has been proposed to speed up this natural CO(2) sequestration ('enhanced weathering'). While agriculture may offer an existing infrastructure, weathering rate and impacts on soil and plant are largely unknown. Our objectives were to assess weathering of olivine in soil, and its effects on plant growth and nutrient uptake. In a pot experiment with perennial ryegrass (Lolium perenne L.), weathering during 32 weeks was inferred from bioavailability of magnesium (Mg) in soil and plant. Olivine doses were equivalent to 1630 (OLIV1), 8150, 40700 and 204000 (OLIV4) kg ha(-1). Alternatively, the soluble Mg salt kieserite was applied for reference. Olivine increased plant growth (+15.6%) and plant K concentration (+16.5%) in OLIV4. At all doses, olivine increased bioavailability of Mg and Ni in soil, as well as uptake of Mg, Si and Ni in plants. Olivine suppressed Ca uptake. Weathering estimated from a Mg balance was equivalent to 240 kg ha(-1) (14.8% of dose, OLIV1) to 2240 kg ha(-1) (1.1%, OLIV4). This corresponds to gross CO(2) sequestration of 290 to 2690 kg ha(-1) (29 10(3) to 269 10(3) kg km(-2).) Alternatively, weathering estimated from similarity with kieserite treatments ranged from 13% to 58% for OLIV1. The Olsen model for olivine carbonation predicted 4.0% to 9.0% weathering for our case, independent of olivine dose. Our % values observed at high doses were smaller than this, suggesting negative feedbacks in soil. Yet, weathering appears fast enough to support the 'enhanced weathering' concept. In agriculture, olivine doses must remain within limits to avoid imbalances in plant nutrition, notably at low Ca availability; and to avoid Ni accumulation in soil and crop.

  9. Olivine Weathering in Soil, and Its Effects on Growth and Nutrient Uptake in Ryegrass (Lolium perenne L.): A Pot Experiment

    PubMed Central

    ten Berge, Hein F. M.; van der Meer, Hugo G.; Steenhuizen, Johan W.; Goedhart, Paul W.; Knops, Pol; Verhagen, Jan

    2012-01-01

    Mineral carbonation of basic silicate minerals regulates atmospheric CO2 on geological time scales by locking up carbon. Mining and spreading onto the earth's surface of fast-weathering silicates, such as olivine, has been proposed to speed up this natural CO2 sequestration (‘enhanced weathering’). While agriculture may offer an existing infrastructure, weathering rate and impacts on soil and plant are largely unknown. Our objectives were to assess weathering of olivine in soil, and its effects on plant growth and nutrient uptake. In a pot experiment with perennial ryegrass (Lolium perenne L.), weathering during 32 weeks was inferred from bioavailability of magnesium (Mg) in soil and plant. Olivine doses were equivalent to 1630 (OLIV1), 8150, 40700 and 204000 (OLIV4) kg ha−1. Alternatively, the soluble Mg salt kieserite was applied for reference. Olivine increased plant growth (+15.6%) and plant K concentration (+16.5%) in OLIV4. At all doses, olivine increased bioavailability of Mg and Ni in soil, as well as uptake of Mg, Si and Ni in plants. Olivine suppressed Ca uptake. Weathering estimated from a Mg balance was equivalent to 240 kg ha−1 (14.8% of dose, OLIV1) to 2240 kg ha−1 (1.1%, OLIV4). This corresponds to gross CO2 sequestration of 290 to 2690 kg ha−1 (29 103 to 269 103 kg km−2.) Alternatively, weathering estimated from similarity with kieserite treatments ranged from 13% to 58% for OLIV1. The Olsen model for olivine carbonation predicted 4.0% to 9.0% weathering for our case, independent of olivine dose. Our % values observed at high doses were smaller than this, suggesting negative feedbacks in soil. Yet, weathering appears fast enough to support the ‘enhanced weathering’ concept. In agriculture, olivine doses must remain within limits to avoid imbalances in plant nutrition, notably at low Ca availability; and to avoid Ni accumulation in soil and crop. PMID:22912685

  10. High intraspecific ability to adjust both carbon uptake and allocation under light and nutrient reduction in Halimium halimifolium L.

    PubMed

    Wegener, Frederik; Beyschlag, Wolfram; Werner, Christiane

    2015-01-01

    The allocation of recently assimilated carbon (C) by plants depends on developmental stage and on environmental factors, but the underlying mechanisms are still a matter of debate. In the present study, we investigated the regulation of C uptake and allocation and their adjustments during plant growth. We induced different allocation strategies in the Mediterranean shrub Halimium halimifolium L. by a reduction of light (Low L treatment) and nutrient availability (Low N treatment) and analyzed allocation parameters as well as morphological and physiological traits for 15 months. Further, we conducted a (13)CO2 pulse-labeling and followed the way of recently assimilated carbon to eight different tissue classes and respiration for 13 days. The plant responses were remarkably distinct in our study, with mainly morphological/physiological adaptions in case of light reduction and adjustment of C allocation in case of nutrient reduction. The transport of recently assimilated C to the root system was enhanced in amount (c. 200%) and velocity under nutrient limited conditions compared to control plants. Despite the 57% light reduction the total biomass production was not affected in the Low L treatment. The plants probably compensated light reduction by an improvement of their ability to fix C. Thus, our results support the concept that photosynthesis is, at least in a medium term perspective, influenced by the C demand of the plant and not exclusively by environmental factors. Finally, our results indicate that growing heterotrophic tissues strongly reduce the C reflux from storage and structural C pools and therefore enhance the fraction of recent assimilates allocated to respiration. We propose that this interruption of the C reflux from storage and structural C pools could be a regulation mechanism for C translocation in plants.

  11. High intraspecific ability to adjust both carbon uptake and allocation under light and nutrient reduction in Halimium halimifolium L.

    PubMed Central

    Wegener, Frederik; Beyschlag, Wolfram; Werner, Christiane

    2015-01-01

    The allocation of recently assimilated carbon (C) by plants depends on developmental stage and on environmental factors, but the underlying mechanisms are still a matter of debate. In the present study, we investigated the regulation of C uptake and allocation and their adjustments during plant growth. We induced different allocation strategies in the Mediterranean shrub Halimium halimifolium L. by a reduction of light (Low L treatment) and nutrient availability (Low N treatment) and analyzed allocation parameters as well as morphological and physiological traits for 15 months. Further, we conducted a 13CO2 pulse-labeling and followed the way of recently assimilated carbon to eight different tissue classes and respiration for 13 days. The plant responses were remarkably distinct in our study, with mainly morphological/physiological adaptions in case of light reduction and adjustment of C allocation in case of nutrient reduction. The transport of recently assimilated C to the root system was enhanced in amount (c. 200%) and velocity under nutrient limited conditions compared to control plants. Despite the 57% light reduction the total biomass production was not affected in the Low L treatment. The plants probably compensated light reduction by an improvement of their ability to fix C. Thus, our results support the concept that photosynthesis is, at least in a medium term perspective, influenced by the C demand of the plant and not exclusively by environmental factors. Finally, our results indicate that growing heterotrophic tissues strongly reduce the C reflux from storage and structural C pools and therefore enhance the fraction of recent assimilates allocated to respiration. We propose that this interruption of the C reflux from storage and structural C pools could be a regulation mechanism for C translocation in plants. PMID:26300906

  12. Effect of fouling organisms on food uptake and nutrient release of scallop ( Chlamys nobilis, Reeve) cultured in Daya Bay

    NASA Astrophysics Data System (ADS)

    Su, Zhenxia; Xiao, Hui; Yan, Yan; Huang, Liangmin

    2008-02-01

    Biofouling is an important factor that affects the bivalve farming industry. Fouling organisms may reduce growth and survival rate of the cultured species. Fouler are often filter feeders, so they are potential competitors for food resource with the cultured species. The present study was conducted to measure the impact of fouling on food uptake and nutrient release in April and June, 2006 in Daya Bay near Guangzhou, China. Results showed that fouling organisms had significant effect on food uptake and nutrient release. The chlorophyll a uptake rate of fouled scallops was 7.53Lh-1±1.416Lh-1 and 11.94Lh-1±2.497Lh-1 in April and June, respectively, significantly higher than those of cleaned scallops, i.e., 4.23Lh-1±2.744Lh-1 and 2.57Lh-1±1.832Lh-1 respectively. The consumption of total particulate matter by fouled scallops in April and June was 5.52Lh-1±0.818Lh-1 and 3.07Lh-1±0.971Lh-1, respectively; the corresponding results for cleaned scallops are 2.49Lh-1±0.614Lh-1 and 2.37±1.214Lh-1, respectively. Fouling increased ammonia release significantly. The ammonia release rate of fouled scallops was 33.81Lh-1±7.699Lh-1 and 76.39Lh-1±9.251Lh-1 in April and June, while cleaned scallops released 2.46Lh-1±0.511Lh-1 and 7.23Lh-1±1.026Lh-1 ammonia, respectively. Phosphate release of fouled scallops was 22.72Lh-1±9.978Lh-1 in June and cleaned scallops released phosphate 6.01Lh-1±0.876Lh-1 in April. Therefore, fouling contributed much to food reduction and concentration increase of ammonia and phosphate in water.

  13. Extracellular enzyme activities and nutrient availability during artificial groundwater recharge.

    PubMed

    Kolehmainen, Reija E; Korpela, Jaana P; Münster, Uwe; Puhakka, Jaakko A; Tuovinen, Olli H

    2009-02-01

    Natural organic matter (NOM) removal is the main objective of artificial groundwater recharge (AGR) for drinking water production and biodegradation plays a substantial role in this process. This study focused on the biodegradation of NOM and nutrient availability for microorganisms in AGR by the determination of extracellular enzyme activities (EEAs) and nutrient concentrations along a flow path in an AGR aquifer (Tuusula Water Works, Finland). Natural groundwater in the same area but outside the influence of recharge was used as a reference. Determination of the specific alpha-d-glucosidase (alpha-Glu), beta-d-glucosidase (beta-Glu), phosphomonoesterase (PME), leucine aminopeptidase (LAP) and acetate esterase (AEST) activities by fluorogenic model substrates revealed major increases in the enzymatic hydrolysis rates in the aquifer within a 10m distance from the basin. The changes in the EEAs along the flow path occurred simultaneously with decreases in nutrient concentrations. The results support the assumption that the synthesis of extracellular enzymes in aquatic environments is up and down regulated by nutrient availability. The EEAs in the basin sediment and pore water samples (down to 10cm) were in the same order of magnitude as in the basin water, suggesting similar nutritional conditions. Phosphorus was likely to be the limiting nutrient at this particular AGR site. Furthermore, the extracellular enzymes functioned in a synergistic and cooperative way.

  14. Colonisation of a Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen with indigenous arbuscular mycorrhizal fungal mixture induces changes in heavy metal and nutrient uptake.

    PubMed

    Vogel-Mikus, Katarina; Pongrac, Paula; Kump, Peter; Necemer, Marijan; Regvar, Marjana

    2006-01-01

    Plants of the Zn, Cd and Pb hyperaccumulator Thlaspi praecox Wulfen (Brassicaceae) inoculated or not with indigenous arbuscular mycorrhizal (AM) fungal mixture were grown in a highly Cd, Zn and Pb contaminated substrate in order to evaluate the functionality of symbiosis and assess the possible impact of AM colonisation on heavy metal uptake and tolerance. The results suggest AM development in the metal hyperaccumulating T. praecox is favoured at elevated nutrient demands, e.g. during the reproductive period. AM colonisation parameters positively correlated with total soil Cd and Pb. Colonised plants showed significantly improved nutrient and a decreased Cd and Zn uptake as revealed by TRXRF, thus confirming the functionality of the symbiosis. Reduced heavy metal uptake, especially at higher soil metal contents, indicates a changed metal tolerance strategy in colonised T. praecox plants. This is to our knowledge the first report on AM colonisation of the Zn, Cd and Pb hyperaccumulator T. praecox in a greenhouse experiment.

  15. Prospective Zinc Solubilising Bacteria for Enhanced Nutrient Uptake and Growth Promotion in Maize (Zea mays L.)

    PubMed Central

    Goteti, Praveen Kumar; Emmanuel, Leo Daniel Amalraj; Desai, Suseelendra; Shaik, Mir Hassan Ahmed

    2013-01-01

    Zinc (Zn) is one of the essential micronutrients required for optimum plant growth. Substantial quantity of applied inorganic zinc in soil is converted into unavailable form. Zinc solubilising bacteria are potential alternates for zinc supplement. Among 10 strains screened for Zn solubilisation, P29, P33, and B40 produced 22.0 mm clear haloes on solid medium amended with ZnCO3. Similarly, P17 and B40 showed 31.0 mm zone in ZnO incorporated medium. P29 and B40 showed significant release of Zn in broth amended with ZnCO3 (17 and 16.8 ppm) and ZnO (18 and 17 ppm), respectively. The pH of the broth was almost acidic in all the cases ranging from 3.9 to 6.1 in ZnCO3 and from 4.1 to 6.4 in ZnO added medium. Short term pot culture experiment with maize revealed that seed bacterization with P29 @ 10 g·kg−1 significantly enhanced total dry mass (12.96 g) and uptake of N (2.268%), K (2.0%), Mn (60 ppm), and Zn (278.8 ppm). PMID:24489550

  16. Influence of Mount St. Helens volcanic ash on alfalfa growth and nutrient uptake

    SciTech Connect

    Mahler, R.L.

    1984-01-01

    Concern has been expressed that large amounts of volcanic ash from the May 18, 1980 eruption of Mount St. Helens may have created potential nutritional problems associated with forage production in northern Idaho and eastern Washington to the extent that adjustments need to be made in soil test correlation data. The objectives of this greenhouse study were to : (1) determine the effect of varying amounts of volcanic ash mixed into soils of northern Idaho on total alfalfa biomass production, and (2) to determine the effect of various soil/ash mixtures on the nutrient concentrations of P, K, S, Ca, Mg, Mn and Zn in alfalfa. Alfalfa was grown in eight different northern Idaho soils amended with differing levels of volcanic ash (0, 20, 35, 50 and 75%) in the greenhouse. The alfalfa seeds were inoculated and fertilizer P and S were added to all treatments. Total plant biomass and P, K, S, Ca, Mg, Mn and Zn plant concentrations were measured. The eight were pooled for analysis and it was found that increasing amounts of volcanic ash increased alfalfa biomass production. Plant P, S, Ca, Mg and Zn concentrations also increased with increasing levels of ash. Conversely, increasing levels of ash resulted in lower alfalfa tissue K and Mn concentrations. 13 references, 7 figures.

  17. Is the stokeslet model sufficient for finding nutrient uptake of microscopic suspension feeders?

    NASA Astrophysics Data System (ADS)

    Lutton, Alexander T.; Pepper, Rachel E.

    2016-11-01

    Microscopic sessile suspension feeders are part of many aquatic ecosystems. They are single-celled, vary in size from a few to about 100 microns in length, live attached to substrates, and serve important ecological roles as both food for larger organisms and consumers of bacteria and other small particles. These organisms create currents in order to bring food toward them. Understanding these currents may allow us not only deeper insight into the ecology of aquatic ecosystems, but also may enable innovation in water treatment. Simulations of the feeding currents of these organisms typically use a simple model that places a stokeslet above an infinite plane boundary representing the surface of attachment. This model produces a useful approximation for the flow field of the organism, but may be of limited accuracy when the organism is near the boundary. We create a different model composed of a stokeslet and a potential dipole, which form a sphere. This sphere has a sin(θ) tangential velocity boundary condition, accounting for the cell body. Using nutrient flux to the organism as our metric, we investigate the discrepancy between the spherical and stokeslet models in order to determine the efficacy of the stokeslet model as an approximation of single-celled suspension feeders.

  18. Atypical Hydrogen Uptake on Chemically Activated, Ultramicroporous Carbon

    SciTech Connect

    Bhat, Vinay V; Contescu, Cristian I; Gallego, Nidia C; Baker, Frederick S

    2010-01-01

    Hydrogen adsorption at near-ambient temperatures on ultramicroporous carbon (UMC), derived through secondary chemical activation from a wood-based activated carbon was studied using volumetric and gravimetric methods. The results showed that physisorption is accompanied by a process of different nature that causes slow uptake at high pressures and hysteresis on desorption. In combination, this results in unusually high levels of hydrogen uptake at near-ambient temperatures and pressures (e.g. up to 0.8 wt % at 25 oC and 2 MPa). The heat of adsorption corresponding to the slow process leading to high uptake (17 20 kJ/mol) is higher than usually reported for carbon materials, but the adsorption kinetics is slow, and the isotherms exhibit pronounced hysteresis. These unusual properties were attributed to contributions from polarization-enhanced physisorption caused by traces of alkali metals residual from chemical activation. The results support the hypothesis that polarization-induced physisorption in high surface area carbons modified with traces of alkali metal ions is an alternate route for increasing the hydrogen storage capacity of carbon adsorbents.

  19. Elemental ratios and the uptake and release of nutrients by phytoplankton and bacteria in three lakes of the Canadian shield.

    PubMed

    Elser, J J; Chrzanowski, T H; Sterner, R W; Schampel, J H; Foster, D K

    1995-03-01

    The dynamics of carbon (C), nitrogen (N), and phosphorus (P), elemental ratios, and dark uptake/release of N and P in bacterial and phytoplankton size fractions were studied during summer 1992 in three lakes of contrasting food web structure and trophic status (L240, L110, L227). We wished to determine if phytoplankton and bacteria differed in their elemental characteristics and to evaluate whether the functional role of bacteria in nutrient cycling (i.e., as sink or source) depended on bacterial elemental characteristics. Bacterial contributions to total suspended particulate material and to fluxes of nutrients in the dark were substantial and varied for different elements. This indicated that some techniques for assaying phytoplankton physiological condition are compromised by bacterial contributions. C/N ratios were generally less variable than C/P and N/P ratios. Both elemental ratios and biomass-normalized N and P flux indicated that phytoplankton growth in each lake was predominantly P-limited, although in L227 these data reflect the dominance of N-fixing cyanobacteria, and N was likely limiting early in the sampling season. In L227, phytoplankton N/P ratio and biomass-normalized N flux were negatively correlated, indicating that flux data were likely a reasonable measure of the N status of the phytoplankton. However, for L227 phytoplankton, P-flux per unit biomass was a hyperbolic function of N/P, suggesting that the dominant L227 cyanobacteria have a limited uptake and storage capacity and that P-flux per unit biomass may not be a good gauge of the P-limitation status of phytoplankton in this situation. Examination of N-flux data in the bacterial size fraction relative to the N/P ratio of the bacteria revealed a threshold N/P ratio (∼22:1 N/P, by atoms), below which, bacteria took up and sequestered added N, and above which, N was released. Thus, the functional role of bacteria in N cycling in these ecosystems depended on their N/P stoichiometry.

  20. Contrary seasonal changes of rates of nutrient uptake, organ mass, and voluntary food intake in red deer (Cervus elaphus)

    PubMed Central

    Beiglböck, Christoph; Burmester, Marion; Guschlbauer, Maria; Lengauer, Astrid; Schröder, Bernd; Wilkens, Mirja; Breves, Gerhard

    2015-01-01

    Northern ungulates acclimatize to winter conditions with restricted food supply and unfavorable weather conditions by reducing energy expenditure and voluntary food intake. We investigated in a study on red deer whether rates of peptide and glucose transport in the small intestines are also reduced during winter as part of the thrifty phenotype of winter-acclimatized animals, or whether transport rates are increased during winter in order to exploit poor forage more efficiently. Our results support the latter hypothesis. We found in a feeding experiment that total energy intake was considerably lower during winter despite ad libitum feeding. Together with reduced food intake, mass of visceral organs was significantly lower and body fat reserves were used as metabolic fuel in addition to food. However, efficacy of nutrient absorption seemed to be increased simultaneously. Extraction of crude protein from forage was higher in winter animals, at any level of crude protein intake, as indicated by the lower concentration of crude protein in feces. In line with these in vivo results, Ussing chamber experiments revealed greater electrogenic responses to both peptides and glucose in the small intestines of winter-acclimatized animals, and peptide uptake into jejunal brush-border membrane vesicles was increased. We conclude that reduced appetite of red deer during winter avoids energy expenditure for unproductive search of scarcely available food and further renders the energetically costly maintenance of a large gut and visceral organs unnecessary. Nevertheless, extraction of nutrients from forage is more efficient in the winter to attenuate an inevitably negative energy balance. PMID:26017492

  1. Calcium-Activated Phosphate Uptake in Contracting Corn Mitochondria 1

    PubMed Central

    Truelove, B.; Hanson, J. B.

    1966-01-01

    The phosphate inhibition of succinate-powered contraction in corn mitochondria can be reversed with calcium. Associated with this reversal is an accumulation of phosphate and calcium. Both ions are essential for accumulation, although strontium will partially substitute for calcium. Arsenate does not substitute for phosphate except in producing the inhibition of contraction. The antibiotics oligomycin and aurovertin do not block the phosphate inhibition of contraction or the calcium-activated phosphate uptake associated with the release of the inhibition. Dinitrophenol uncouples the phosphate uptake but permits full contraction. Calcium promotes inorganic phosphate accumulation in root tissue as well as in mitochondria. The results are discussed from the viewpoint of theories of calcium reaction with high energy intermediates of oxidative phosphorylation. It is concluded that calcium probably reacts with X∼P in corn mitochondria, rather than with X∼I as with animal mitochondria. PMID:16656343

  2. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    USGS Publications Warehouse

    Yeo, In-Young; Lee, Sangchui; Sadeghi, Ali M.; Beeson, Peter C.; Hively, W. Dean; McCarty, Greg W.; Lang, Megan W.

    2013-01-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay Watershed (CBW), which is located in the Mid-Atlantic US, winter cover crop use has been emphasized and federal and state cost-share programs are available to farmers to subsidize the cost of winter cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops at the watershed scale and to identify critical source areas of high nitrate export. A physically-based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data and satellite-based estimates of winter cover crop species performance to simulate hydrological processes and nutrient cycling over the period of 1991–2000. Multiple scenarios were developed to obtain baseline information on nitrate loading without winter cover crops planted and to investigate how nitrate loading could change with different winter cover crop planting scenarios, including different species, planting times, and implementation areas. The results indicate that winter cover crops had a negligible impact on water budget, but significantly reduced nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading was approximately 14 kg ha−1, but it decreased to 4.6–10.1 kg ha−1 with winter cover crops resulting in a reduction rate of 27–67% at the watershed scale. Rye was most effective, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of winter cover crops (~30 days of additional growing days) was crucial, as it lowered nitrate export by an additional ~2 kg ha−1 when compared to late planting scenarios. The effectiveness of cover cropping increased with increasing extent of winter cover crop implementation. Agricultural fields with well-drained soils

  3. Assessing winter cover crop nutrient uptake efficiency using a water quality simulation model

    NASA Astrophysics Data System (ADS)

    Yeo, I.-Y.; Lee, S.; Sadeghi, A. M.; Beeson, P. C.; Hively, W. D.; McCarty, G. W.; Lang, M. W.

    2014-12-01

    Winter cover crops are an effective conservation management practice with potential to improve water quality. Throughout the Chesapeake Bay watershed (CBW), which is located in the mid-Atlantic US, winter cover crop use has been emphasized, and federal and state cost-share programs are available to farmers to subsidize the cost of cover crop establishment. The objective of this study was to assess the long-term effect of planting winter cover crops to improve water quality at the watershed scale (~ 50 km2) and to identify critical source areas of high nitrate export. A physically based watershed simulation model, Soil and Water Assessment Tool (SWAT), was calibrated and validated using water quality monitoring data to simulate hydrological processes and agricultural nutrient cycling over the period of 1990-2000. To accurately simulate winter cover crop biomass in relation to growing conditions, a new approach was developed to further calibrate plant growth parameters that control the leaf area development curve using multitemporal satellite-based measurements of species-specific winter cover crop performance. Multiple SWAT scenarios were developed to obtain baseline information on nitrate loading without winter cover crops and to investigate how nitrate loading could change under different winter cover crop planting scenarios, including different species, planting dates, and implementation areas. The simulation results indicate that winter cover crops have a negligible impact on the water budget but significantly reduce nitrate leaching to groundwater and delivery to the waterways. Without winter cover crops, annual nitrate loading from agricultural lands was approximately 14 kg ha-1, but decreased to 4.6-10.1 kg ha-1 with cover crops resulting in a reduction rate of 27-67% at the watershed scale. Rye was the most effective species, with a potential to reduce nitrate leaching by up to 93% with early planting at the field scale. Early planting of cover crops (~ 30

  4. Human pancreatic cancer tumors are nutrient poor and tumor cells actively scavenge extracellular protein.

    PubMed

    Kamphorst, Jurre J; Nofal, Michel; Commisso, Cosimo; Hackett, Sean R; Lu, Wenyun; Grabocka, Elda; Vander Heiden, Matthew G; Miller, George; Drebin, Jeffrey A; Bar-Sagi, Dafna; Thompson, Craig B; Rabinowitz, Joshua D

    2015-02-01

    Glucose and amino acids are key nutrients supporting cell growth. Amino acids are imported as monomers, but an alternative route induced by oncogenic KRAS involves uptake of extracellular proteins via macropinocytosis and subsequent lysosomal degradation of these proteins as a source of amino acids. In this study, we examined the metabolism of pancreatic ductal adenocarcinoma (PDAC), a poorly vascularized lethal KRAS-driven malignancy. Metabolomic comparisons of human PDAC and benign adjacent tissue revealed that tumor tissue was low in glucose, upper glycolytic intermediates, creatine phosphate, and the amino acids glutamine and serine, two major metabolic substrates. Surprisingly, PDAC accumulated essential amino acids. Such accumulation could arise from extracellular proteins being degraded through macropinocytosis in quantities necessary to meet glutamine requirements, which in turn produces excess of most other amino acids. Consistent with this hypothesis, active macropinocytosis is observed in primary human PDAC specimens. Moreover, in the presence of physiologic albumin, we found that cultured murine PDAC cells grow indefinitely in media lacking single essential amino acids and replicate once in the absence of free amino acids. Growth under these conditions was characterized by simultaneous glutamine depletion and essential amino acid accumulation. Overall, our findings argue that the scavenging of extracellular proteins is an important mode of nutrient uptake in PDAC.

  5. Human pancreatic cancer tumors are nutrient poor and tumor cells actively scavenge extracellular protein

    PubMed Central

    Kamphorst, Jurre J.; Nofal, Michel; Commisso, Cosimo; Hackett, Sean R.; Lu, Wenyun; Grabocka, Elda; Vander Heiden, Matthew G.; Miller, George; Drebin, Jeffrey A.; Bar-Sagi, Dafna; Thompson, Craig B.; Rabinowitz, Joshua D.

    2014-01-01

    Glucose and amino acids are key nutrients supporting cell growth. Amino acids are imported as monomers, but an alternative route induced by oncogenic KRAS involves uptake of extracellular proteins via macropinocytosis and subsequent lysosomal degradation of these proteins as a source of amino acids. In this study, we examined the metabolism of pancreatic ductal adenocarcinoma (PDAC), a poorly vascularized lethal KRAS-driven malignancy. Metabolomic comparisons of human PDAC and benign adjacent tissue revealed that tumor tissue was low in glucose, upper glycolytic intermediates, creatine phosphate and the amino acids glutamine and serine, two major metabolic substrates. Surprisingly, PDAC accumulated essential amino acids. Such accumulation could arise from extracellular proteins being degraded through macropinocytosis in quantities necessary to meet glutamine requirements, which in turn produces excess of most other amino acids. Consistent with this hypothesis, active macropinocytosis is observed in primary human PDAC specimens. Moreover, in the presence of physiological albumin, we found that cultured murine PDAC cells grow indefinitely in media lacking single essential amino acids, and replicate once in the absence of free amino acids. Growth under these conditions was characterized by simultaneous glutamine depletion and essential amino acid accumulation. Overall, our findings argue that the scavenging of extracellular proteins is an important mode of nutrient uptake in PDAC. PMID:25644265

  6. Effects of Harvesting Intensity and Herbivory by White-tailed Deer on Vegetation and Nutrient Uptake in a Northern Hardwood Forest

    NASA Astrophysics Data System (ADS)

    Yorks, T. E.; Leopold, D. J.; Raynal, D. J.; Murdoch, P. S.; Burns, D. A.

    2003-12-01

    We quantified the response of vegetation and nutrient uptake in a northern hardwood forest in southeastern New York for three to four years after three intensities of harvesting: clearcutting, heavy timber stand improvement (TSI), light TSI (97, 29, and 10% basal area reductions, respectively). We also quantified effects of white-tailed deer (Odocoileus virginianus) herbivory on nutrient retention by vegetation. Total biomass and nutrient accumulation in vegetation was higher after TSI than clearcutting in the first two years but was highest in the fenced clearcut in subsequent years, indicating that TSI or partial harvesting is a viable management tool for harvesting timber while consistently maintaining high rates of nutrient retention. After clearcutting, biomass and nutrient retention were initially dominated by woody stems <1.4 m tall and herbaceous vegetation, but saplings 0.1-5.0 cm DBH became the most important contributors to biomass and nutrient accumulation within four years. However, after both intensities of TSI, trees >5.0 cm DBH continued to account for most biomass and nutrient accumulation whereas understory vegetation accumulated little biomass or nutrients. Heavy TSI resulted in increased regeneration of only two tree species (Acer pensylvanicum, Fagus grandifolia), but clearcutting allowed these two species, mature forest species (A. saccharum, Betula alleghaniensis), and the early successional Prunus pensylvanica to regenerate. Several early successional shrub and herbaceous species were also important to nutrient retention after clearcutting, including Polygonum cilinode, Rubus spp., and Sambucus racemosa. Herbivory by white-tailed deer dramatically reduced biomass and nutrient accumulation by woody stems <5 cm DBH after clearcutting (5.5 vs. 0.7 Mg biomass/ha and 30.4 vs. 6.3 kg N/ha on fenced and unfenced clearcut sites, respectively, after four years), indicating the important influence this herbivore can have on nutrient retention in

  7. Effects of soil temperature on shoot and root growth and nutrient uptake of 5-year-old Norway spruce seedlings.

    PubMed

    Lahti, M; Aphalo, P J; Finér, L; Ryyppö, A; Lehto, T; Mannerkoski, H

    2005-01-01

    Soil temperature is a main factor limiting root growth in the boreal forest. To simulate the possible soil-warming effect of future climate change, 5-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were subjected to three simulated growing seasons in controlled environment rooms. The seedlings were acclimated to a soil temperature of 16 degrees C during the first (GS I) and third growing seasons (GS III), but were assigned to random soil-temperature treatments of 9, 13, 18 and 21 degrees C during the second growing season (GS II). In GS II, shoot diameter growth was lowest in the 21 degrees C treatment and root growth was lowest in the 9 degrees C treatment. In GS III, shoot height and root length growth improved in seedlings that had been kept at 9 degrees C during GS II, indicating compensatory growth in response to increased soil temperature. The temporary decrease in soil temperature had no long-lasting significant effect on seedling biomass or total nutrient uptake. At the end of GS III, fine roots of seedlings exposed to a soil temperature of 21 degrees C in GS II were distributed more evenly between the organic and mineral soil layers than roots of seedlings in the other treatments. During GS II and GS III, root growth started earlier than shoot growth, decreased during the rapid shoot elongation phase and increased again as shoot growth decreased.

  8. Effects of Posidonia oceanica beach-cast on germination, growth and nutrient uptake of coastal dune plants.

    PubMed

    Del Vecchio, Silvia; Marbà, Núria; Acosta, Alicia; Vignolo, Clara; Traveset, Anna

    2013-01-01

    Seagrass meadows play an important role in marine ecosystems. A part of seagrass production is also exported to adjacent coastal terrestrial systems, possibly influencing their functioning. In this work we experimentally analyzed the effect of Posidonia oceanica beach-cast on plant germination, growth, and nutrient uptake of two plant species (Cakile maritima and Elymus farctus) that grow on upper beaches and fore dunes along the Mediterranean coasts. We compared plants growing in simple sand (control) with those growing in a substrate enriched with P. oceanica wrack (treatment) in laboratory. P. oceanica wrack doubled the N substrate pool and kept the substrate humid. Plants growing in the treated substrate grew faster, were twice as large as those growing in the control substrate, while tissues were enriched in N and P (Cakile by the 1.3 fold in N and 2.5 fold in P; Elymus by 1.5 fold in N and 2 fold in P). Our results suggest a positive effect of seagrass litter for the enhancing of dune species, highlighting its role for the conservation of coastal dune ecosystems.

  9. Interactive effects of soil temperature, atmospheric carbon dioxide and soil N on root development, biomass and nutrient uptake of winter wheat during vegetative growth.

    PubMed

    Gavito, M E; Curtis, P S; Mikkelsen, T N; Jakobsen, I

    2001-09-01

    Nutrient requirements for plant growth are expected to rise in response to the predicted changes in CO(2) and temperature. In this context, little attention has been paid to the effects of soil temperature, which limits plant growth at early stages in temperate regions. A factorial growth-room experiment was conducted with winter wheat, varying soil temperature (10 degrees C and 15 degrees C), atmospheric CO(2) concentration (360 and 700 ppm), and N supply (low and high). The hypothesis was that soil temperature would modify root development, biomass allocation and nutrient uptake during vegetative growth and that its effects would interact with atmospheric CO(2) and N availability. Soil temperature effects were confirmed for most of the variables measured and 3-factor interactions were observed for root development, plant biomass components, N-use efficiency, and shoot P content. Importantly, the soil temperature effects were manifest in the absence of any change in air temperature. Changes in root development, nutrient uptake and nutrient-use efficiencies were interpreted as counterbalancing mechanisms for meeting nutrient requirements for plant growth in each situation. Most variables responded to an increase in resource availability in the order: N supply >soil temperature >CO(2).

  10. Effects of enhanced soil P on photosynthesis, root respiration and nutrient uptake of Artemisia tridentata in different photosynthetic photon flux densities and CO[sub 2] conditions

    SciTech Connect

    Cui, M.; Caldwell, M.M. )

    1994-06-01

    Responses of leaf photosynthesis, root respiration and P uptake by Artemisia tridentata seedlings to study root physiological adjustments to utilize available nutrient resources in a changing soil environment. Root respiration was measured for intact root systems in split-root chambers. Increasing P in 0.2 [times] Hoagland's solution from 0.04 mmol to 2.0 mmol increased leaf photosynthesis by 6% in 3 days, increased nighttime leaf respiration rate by 8% and root respiration by 18%. After PPFD was reduced from 800 to 200 [mu]mol m[sup [minus]2]s[sup [minus]1] leaf photosynthesis deceased by 67%, and root respiration by 26% in the following day but then decreased by 35% over the next three days. Shading may limit root growth and nutrient uptake by lowering the carbohydrate supply to root systems.

  11. Effect of dietary phytic acid on performance and nutrient uptake in the small intestine of piglets.

    PubMed

    Woyengo, T A; Weihrauch, D; Nyachoti, C M

    2012-02-01

    An experiment was conducted with piglets to determine the effect of dietary phytic acid supplementation on performance, electrophysiological properties of jejunum mounted in Ussing chambers, sodium-dependent glucose transporter 1 (SGLT1) protein expression in jejunum, and plasma glucose and Na concentrations. Sixteen piglets with an average initial BW of 7.40 ± 0.36 kg were randomly assigned to 2 experimental diets with 8 piglets per diet. The diets were casein-cornstarch-based and were either unsupplemented or supplemented with 2% phytic acid (as Na phytate). The basal diet was formulated to meet the recommendation of NRC (1998) for energy, AA, minerals, and vitamins for piglets. The experiment lasted for 21 d, and at the end, BW gain and feed consumption were determined, and blood samples were collected for determination of plasma glucose and Na concentrations. The piglets were then euthanized to determine jejunal electrophysiological properties (transmural potential difference and short-circuit current) and SGLT1 protein expression. Phytic acid supplementation reduced ADG (P = 0.002), ADFI (P = 0.017), and G:F (P = 0.001) from 316.1 to 198.2 g, 437.4 to 360.3 g, and 0.721 to 0.539 g/g, respectively. Phytic acid supplementation also tended to reduce (P = 0.088) potential difference (-3.80 vs. -2.23 mV) and reduced (P = 0.023) short-circuit current from 8.07 to 0.1 μA/cm(2). However, phytic acid supplementation did not affect SGLT1 protein, and blood plasma glucose and Na concentrations. In conclusion, dietary phytic acid reduced growth performance and transmural short-circuit current in the jejunum of piglets. The reduced transmural short-circuit current in the jejunum by phytic acid implies reduced active Na transport in the jejunum by the phytic acid. Therefore, it seems that dietary phytic acid reduces growth performance of pigs partly through reduced capacity of the small intestine to absorb Na.

  12. Uptake of radioiodide by Paenibacillus sp., Pseudomonas sp., Burkholderia sp. and Rhodococcus sp. isolated from a boreal nutrient-poor bog.

    PubMed

    Lusa, Merja; Lehto, Jukka; Aromaa, Hanna; Knuutinen, Jenna; Bomberg, Malin

    2016-06-01

    Radionuclides, like radioiodine ((129)I), may escape deep geological nuclear waste repositories and migrate to the surface ecosystems. In surface ecosystems, microorganisms can affect their movement. Iodide uptake of six bacterial strains belonging to the genera Paenibacillus, Pseudomonas, Burkholderia and Rhodococcus isolated from an acidic boreal nutrient-poor bog was tested. The tests were run in four different growth media at three temperatures. All bacterial strains removed iodide from the solution with the highest efficiency shown by one of the Paenibacillus strains with >99% of iodide removed from the solution in one of the used growth media. Pseudomonas, Rhodococcus and one of the two Paenibacillus strains showed highest iodide uptake in 1% yeast extract with maximum values for the distribution coefficient (Kd) ranging from 90 to 270L/kg DW. The Burkholderia strain showed highest uptake in 1% Tryptone (maximum Kd 170L/kg DW). The Paenibacillus strain V0-1-LW showed exceptionally high uptake in 0.5% peptone +0.25% yeast extract broth (maximum Kd>1,000,000L/kg DW). Addition of 0.1% glucose to the 0.5% peptone +0.25% yeast extract broth reduced iodide uptake at 4°C and 20°C and enhanced iodide uptake at 37°C compared to the uptake without glucose. This indicates that the uptake of glucose and iodide may be competing processes in these bacteria. We estimated that in in situ conditions of the bog, the bacterial uptake of iodide accounts for approximately 0.1%-0.3% of the total sorption of iodide in the surface, subsurface peat, gyttja and clay layers.

  13. Nutrient deprivation induces the Warburg effect through ROS/AMPK-dependent activation of pyruvate dehydrogenase kinase.

    PubMed

    Wu, Ching-An; Chao, Yee; Shiah, Shine-Gwo; Lin, Wan-Wan

    2013-05-01

    The Warburg effect is known to be crucial for cancer cells to acquire energy. Nutrient deficiencies are an important phenomenon in solid tumors, but the effect on cancer cell metabolism is not yet clear. In this study, we demonstrate that starvation of HeLa cells by incubation with Hank's buffered salt solution (HBSS) induced cell apoptosis, which was accompanied by the induction of reactive oxygen species (ROS) production and AMP-activated protein kinase (AMPK) phosphorylation. Notably, HBSS starvation increased lactate production, cytoplasmic pyruvate content and decreased oxygen consumption, but failed to change the lactate dehydrogenase (LDH) activity or the glucose uptake. We found that HBSS starvation rapidly induced pyruvate dehydrogenase kinase (PDK) activation and pyruvate dehydrogenase (PDH) phosphorylation, both of which were inhibited by compound C (an AMPK inhibitor), NAC (a ROS scavenger), and the dominant negative mutant of AMPK. Our data further revealed the involvement of ROS production in AMPK activation. Moreover, DCA (a PDK inhibitor), NAC, and compound C all significantly decreased HBSS starvation-induced lactate production accompanied by enhancement of HBSS starvation-induced cell apoptosis. Not only in HeLa cells, HBSS-induced lactate production and PDH phosphorylation were also observed in CL1.5, A431 and human umbilical vein endothelial cells. Taken together, we for the first time demonstrated that a low-nutrient condition drives cancer cells to utilize glycolysis to produce ATP, and this increases the Warburg effect through a novel mechanism involving ROS/AMPK-dependent activation of PDK. Such an event contributes to protecting cells from apoptosis upon nutrient deprivation.

  14. The chemokine CCL5 regulates glucose uptake and AMP kinase signaling in activated T cells to facilitate chemotaxis.

    PubMed

    Chan, Olivia; Burke, J Daniel; Gao, Darrin F; Fish, Eleanor N

    2012-08-24

    Recruitment of effector T cells to sites of infection or inflammation is essential for an effective adaptive immune response. The chemokine CCL5 (RANTES) activates its cognate receptor, CCR5, to initiate cellular functions, including chemotaxis. In earlier studies, we reported that CCL5-induced CCR5 signaling activates the mTOR/4E-BP1 pathway to directly modulate mRNA translation. Specifically, CCL5-mediated mTOR activation contributes to T cell chemotaxis by initiating the synthesis of chemotaxis-related proteins. Up-regulation of chemotaxis-related proteins may prime T cells for efficient migration. It is now clear that mTOR is also a central regulator of nutrient sensing and glycolysis. Herein we describe a role for CCL5-mediated glucose uptake and ATP accumulation to meet the energy demands of chemotaxis in activated T cells. We provide evidence that CCL5 is able to induce glucose uptake in an mTOR-dependent manner. CCL5 treatment of ex vivo activated human CD3(+) T cells also induced the activation of the nutrient-sensing kinase AMPK and downstream substrates ACC-1, PFKFB-2, and GSK-3β. Using 2-deoxy-d-glucose, an inhibitor of glucose uptake, and compound C, an inhibitor of AMPK, experimental data are presented that demonstrate that CCL5-mediated T cell chemotaxis is dependent on glucose, as these inhibitors inhibit CCL5-mediated chemotaxis in a dose-dependent manner. Altogether, these findings suggest that both glycolysis and AMPK signaling are required for efficient T cell migration in response to CCL5. These studies extend the role of CCL5 mediated CCR5 signaling beyond lymphocyte chemotaxis and demonstrate a role for chemokines in promoting glucose uptake and ATP production to match energy demands of migration.

  15. Basalt Weathering, Nutrient Uptake, And Carbon Release By An Exotic And A Native Arizona Grass Species Under Different Temperature Conditions

    NASA Astrophysics Data System (ADS)

    Gallas, G.; Dontsova, K.; Chorover, J.; Hunt, E.; Ravi, S.

    2010-12-01

    basalt weathering. All of the leachate samples showed higher pH than the input water, and the pH was elevated in treatments that contained grass. This indicated that in the presence of vegetation there was more proton absorption. The trends in total nitrogen concentrations indicate a dependence on temperature; the same can be said of anion concentrations. Anion leaching is lower at higher temperatures possibly due to greater plant uptake. Both organic and inorganic carbon concentrations were found to be higher in grass treatments than in control treatments. Because both dissolved CO2 and soluble organic exudates encourage mineral dissolution, this could be causative of the weathering enhancements observed. Denudation of nutrient elements differed between plant species and between temperatures, possibly relating to plant uptake and secondary mineral formation. This study gives unique insight into plant-mineral interactions as a function of plant species and temperature that is essential for understanding Earth systems under changing climate.

  16. Mycorrhizal phosphate uptake pathway in maize: vital for growth and cob development on nutrient poor agricultural and greenhouse soils

    PubMed Central

    Willmann, Martin; Gerlach, Nina; Buer, Benjamin; Polatajko, Aleksandra; Nagy, Réka; Koebke, Eva; Jansa, Jan; Flisch, René; Bucher, Marcel

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) form a mutually beneficial symbiosis with plant roots providing predominantly phosphorus in the form of orthophosphate (Pi) in exchange for plant carbohydrates on low P soils. The goal of this work was to generate molecular-genetic evidence in support of a major impact of the mycorrhizal Pi uptake (MPU) pathway on the productivity of the major crop plant maize under field and controlled conditions. Here we show, that a loss-of-function mutation in the mycorrhiza-specific Pi transporter gene Pht1;6 correlates with a dramatic reduction of above-ground biomass and cob production in agro-ecosystems with low P soils. In parallel mutant pht1;6 plants exhibited an altered fingerprint of chemical elements in shoots dependent on soil P availability. In controlled environments mycorrhiza development was impaired in mutant plants when grown alone. The presence of neighboring mycorrhizal nurse plants enhanced the reduced mycorrhiza formation in pht1;6 roots. Uptake of 33P-labeled orthophosphate via the MPU pathway was strongly impaired in colonized mutant plants. Moreover, repression of the MPU pathway resulted in a redirection of Pi to neighboring plants. In line with previous results, our data highlight the relevance of the MPU pathway in Pi allocation within plant communities and in particular the role of Pht1;6 for the establishment of symbiotic Pi uptake and for maize productivity and nutritional value in low-input agricultural systems. In a first attempt to identify cellular pathways which are affected by Pht1;6 activity, gene expression profiling via RNA-Seq was performed and revealed a set of maize genes involved in cellular signaling which exhibited differential regulation in mycorrhizal pht1;6 and control plants. The RNA data provided support for the hypothesis that fungal supply of Pi and/or Pi transport across Pht1;6 affects cell wall biosynthesis and hormone metabolism in colonized root cells. PMID:24409191

  17. The effect of titanium amendment in N-withholding nutrient solution on physiological and photosynthesis attributes and micronutrient uptake of tomato.

    PubMed

    Haghighi, Maryam; Heidarian, Salman; Teixeira da Silva, Jaime A

    2012-12-01

    Titanium (Ti) is a beneficial element that promotes growth and biomass production although the mechanism by which this improvement takes place is still unclear, as are other effects on plants, although it is believed that Ti can compensate for N deficiency. To prove this hypothesis, a hydroponic experiment was designed to investigate the effect of adding Ti to a nutrient solution on the nutrient uptake of tomato (Lycopersicon esculentum L.) by withholding N within the nutrient solution (NS) by 25 % (NS2) and by 50 % (NS1). Ti was added at 1 and 2 mg L⁻¹. When Ti was added to nutrient solution, the elemental concentration in tomato changed significantly: K, Ca, Fe, and Zn decreased while Ti increased. As the concentration of N in nutrient solution decreased, the Ca and Ti concentration of tomato leaves decreased and the K, Mn, Fe, Cu, and Zn concentration increased. As the N concentration in nutrient solution increased, the Ca concentration decreased although the application of Ti compensated for Ca concentration in NS1. All the photosynthetic attributes and physiological characteristics, including flower induction, decreased when the N concentration of NS decreased by 50 %, although this decrease could be compensated by applying 1 mg L⁻¹ Ti. This has valuable and practical applications and implications for tomato hydroponic culture.

  18. Studies on nutrient uptake of rice and characteristics of soil microorganisms in a long-term fertilization experiments for irrigated rice.

    PubMed

    Zhang, Qi-chun; Wang, Guang-huo

    2005-02-01

    The ecosystem characteristics of soil microorganism and the nutrient uptake of irrigated rice were investigated in a split-block experiment with different fertilization treatments, including control (no fertilizer application), PK, NK, NP, NPK fertilization, in the main block, and conventional rice and hybrid rice comparison, in the sub block. Average data of five treatments in five years indicated that the indigenous N supply (INS) capacity ranged from 32.72 to 93.21 kg/ha; that indigenous P supply (IPS) capacity ranged from 7.42 to 32.25 kg/ha; and that indigenous K supply (IKS) capacity ranged from 16.24 to 140.51 kg/ha, which showed that soil available nutrient pool depletion might occur very fast and that P, K deficiency has become a constraint to increasing yields of consecutive crops grown without fertilizer application. It was found that soil nutrient deficiency and unbalanced fertilization to rice crop had negative effect on the diversity of the microbial community and total microbial biomass in the soil. The long-term fertilizer experiment (LTFE) also showed that balanced application of N, P and K promoted microbial biomass growth and improvement of community composition. Unbalanced fertilization reduced microbial N and increased C/N ratio of the microbial biomass. Compared with inbred rice, hybrid rice behavior is characterized by physiological advantage in nutrient uptake and lower internal K use efficiency.

  19. Study of glucose uptake activity of Helicteres isora Linn. fruits in L-6 cell lines

    PubMed Central

    Gupta, R. N.; Pareek, Anil; Suthar, Manish; Rathore, Garvendra S.; Basniwal, Pawan K.; Jain, Deepti

    2009-01-01

    The effect of hot water extract of fruits of Helicteres isora on glucose uptake was studied in rodent skeletal muscle cells (L-6 cells) involved in glucose utilization. H. isora is an antidiabetic medicinal plant being used in Indian traditional medicine. Hot water extracts were analysed for glucose uptake activity and found to be significantly active at 200 μg/ml dose comparable with insulin and metformin. Elevation of glucose uptake by H. isora in association with glucose transport supported the upregulation of glucose uptake. It was concluded that hot water extract of H. isora activate glucose uptake in L-6 cell line of mouse skeletal muscles. PMID:20336200

  20. Study of glucose uptake activity of Helicteres isora Linn. fruits in L-6 cell lines.

    PubMed

    Gupta, R N; Pareek, Anil; Suthar, Manish; Rathore, Garvendra S; Basniwal, Pawan K; Jain, Deepti

    2009-10-01

    The effect of hot water extract of fruits of Helicteres isora on glucose uptake was studied in rodent skeletal muscle cells (L-6 cells) involved in glucose utilization. H. isora is an antidiabetic medicinal plant being used in Indian traditional medicine. Hot water extracts were analysed for glucose uptake activity and found to be significantly active at 200 mug/ml dose comparable with insulin and metformin. Elevation of glucose uptake by H. isora in association with glucose transport supported the upregulation of glucose uptake. It was concluded that hot water extract of H. isora activate glucose uptake in L-6 cell line of mouse skeletal muscles.

  1. Cellular uptake and anticancer activity of carboxylated gallium corroles.

    PubMed

    Pribisko, Melanie; Palmer, Joshua; Grubbs, Robert H; Gray, Harry B; Termini, John; Lim, Punnajit

    2016-04-19

    We report derivatives of gallium(III) tris(pentafluorophenyl)corrole, 1 [Ga(tpfc)], with either sulfonic (2) or carboxylic acids (3, 4) as macrocyclic ring substituents: the aminocaproate derivative, 3 [Ga(ACtpfc)], demonstrated high cytotoxic activity against all NCI60 cell lines derived from nine tumor types and confirmed very high toxicity against melanoma cells, specifically the LOX IMVI and SK-MEL-28 cell lines. The toxicities of 1, 2, 3, and 4 [Ga(3-ctpfc)] toward prostate (DU-145), melanoma (SK-MEL-28), breast (MDA-MB-231), and ovarian (OVCAR-3) cancer cells revealed a dependence on the ring substituent: IC50values ranged from 4.8 to >200 µM; and they correlated with the rates of uptake, extent of intracellular accumulation, and lipophilicity. Carboxylated corroles 3 and 4, which exhibited about 10-fold lower IC50values (<20 µM) relative to previous analogs against all four cancer cell lines, displayed high efficacy (Emax= 0). Confocal fluorescence imaging revealed facile uptake of functionalized gallium corroles by all human cancer cells that followed the order: 4 > 3 > 2 > 1 (intracellular accumulation of gallium corroles was fastest in melanoma cells). We conclude that carboxylated gallium corroles are promising chemotherapeutics with the advantage that they also can be used for tumor imaging.

  2. Cellular uptake and anticancer activity of carboxylated gallium corroles

    PubMed Central

    Pribisko, Melanie; Palmer, Joshua; Grubbs, Robert H.; Gray, Harry B.; Termini, John; Lim, Punnajit

    2016-01-01

    We report derivatives of gallium(III) tris(pentafluorophenyl)corrole, 1 [Ga(tpfc)], with either sulfonic (2) or carboxylic acids (3, 4) as macrocyclic ring substituents: the aminocaproate derivative, 3 [Ga(ACtpfc)], demonstrated high cytotoxic activity against all NCI60 cell lines derived from nine tumor types and confirmed very high toxicity against melanoma cells, specifically the LOX IMVI and SK-MEL-28 cell lines. The toxicities of 1, 2, 3, and 4 [Ga(3-ctpfc)] toward prostate (DU-145), melanoma (SK-MEL-28), breast (MDA-MB-231), and ovarian (OVCAR-3) cancer cells revealed a dependence on the ring substituent: IC50 values ranged from 4.8 to >200 µM; and they correlated with the rates of uptake, extent of intracellular accumulation, and lipophilicity. Carboxylated corroles 3 and 4, which exhibited about 10-fold lower IC50 values (<20 µM) relative to previous analogs against all four cancer cell lines, displayed high efficacy (Emax = 0). Confocal fluorescence imaging revealed facile uptake of functionalized gallium corroles by all human cancer cells that followed the order: 4 >> 3 > 2 >> 1 (intracellular accumulation of gallium corroles was fastest in melanoma cells). We conclude that carboxylated gallium corroles are promising chemotherapeutics with the advantage that they also can be used for tumor imaging. PMID:27044076

  3. 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

    2015-06-09

    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.

  4. 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

  5. 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.

  6. Phorbol ester stimulates secretory activity while inhibiting receptor-activated aminopyrine uptake by gastric glands

    SciTech Connect

    Brown, M.R.; Chew, C.S.

    1986-03-05

    Both cyclic AMP-dependent and -independent secretagogues stimulate pepsinogen release, respiration and H/sup +/ secretory activity (AP uptake) in rabbit gastric glands. 12-O-tetradecanoylphorbol-13-acetate (T), a diacyglycerol analog, activates protein kinase C (PKC) and stimulates secretion in many systems. T stimulated respiration and pepsinogen release by glands and increased AP uptake by both glands and purified parietal cells. However, T reduced AP uptake by glands stimulated with carbachol (C) or histamine (H) with an apparent IC/sub 50/ of 1 nM. Preincubation with T for 30 min produced maximum inhibition which was not reversed by removal of T. T accelerated the decline of the transient C peak while the late steady state response to H was most inhibited. H-stimulated AP uptake was also inhibited by 50 ..mu..g/ml 1-oleoyl-2-acetyl-glycerol, a reported PKC activator, but not by the inactive phorbol, 4..cap alpha..-phorbol-12,13-didecanoate. In contrast, T potentiated AP uptake by glands stimulated with submaximal doses of dibutyryl cyclic AMP. These results suggest inhibition by T is a specific effect of PKC activators. The differing effects of T on secretion indicators may result from a dual action of T on receptor and post-receptor intracellular events.

  7. A mechanistic soil biogeochemistry model with explicit representation of microbial and macrofaunal activities and nutrient cycles

    NASA Astrophysics Data System (ADS)

    Fatichi, Simone; Manzoni, Stefano; Or, Dani; Paschalis, Athanasios

    2016-04-01

    The potential of a given ecosystem to store and release carbon is inherently linked to soil biogeochemical processes. These processes are deeply connected to the water, energy, and vegetation dynamics above and belowground. Recently, it has been advocated that a mechanistic representation of soil biogeochemistry require: (i) partitioning of soil organic carbon (SOC) pools according to their functional role; (ii) an explicit representation of microbial dynamics; (iii) coupling of carbon and nutrient cycles. While some of these components have been introduced in specialized models, they have been rarely implemented in terrestrial biosphere models and tested in real cases. In this study, we combine a new soil biogeochemistry model with an existing model of land-surface hydrology and vegetation dynamics (T&C). Specifically the soil biogeochemistry component explicitly separates different litter pools and distinguishes SOC in particulate, dissolved and mineral associated fractions. Extracellular enzymes and microbial pools are explicitly represented differentiating the functional roles of bacteria, saprotrophic and mycorrhizal fungi. Microbial activity depends on temperature, soil moisture and litter or SOC stoichiometry. The activity of macrofauna is also modeled. Nutrient dynamics include the cycles of nitrogen, phosphorous and potassium. The model accounts for feedbacks between nutrient limitations and plant growth as well as for plant stoichiometric flexibility. In turn, litter input is a function of the simulated vegetation dynamics. Root exudation and export to mycorrhiza are computed based on a nutrient uptake cost function. The combined model is tested to reproduce respiration dynamics and nitrogen cycle in few sites where data were available to test plausibility of results across a range of different metrics. For instance in a Swiss grassland ecosystem, fine root, bacteria, fungal and macrofaunal respiration account for 40%, 23%, 33% and 4% of total belowground

  8. Efficacies of designer biochars in improving biomass and nutrient uptake of winter wheat grown in a hard setting subsoil layer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Coastal Plains region of the United States, the hard setting subsoil layer of Norfolk soils results in low water holding capacity and nutrient retention, which often limits root development. In this region, the Norfolk soils are under intensive crop production that further depletes nutrients ...

  9. Uptake and intracellular activity of fluconazole in human polymorphonuclear leukocytes.

    PubMed Central

    Pascual, A; García, I; Conejo, C; Perea, E J

    1993-01-01

    The penetration of fluconazole into human polymorphonuclear leukocytes (PMNs) and tissue culture epithelial cells (McCoy) was evaluated. At different extracellular concentrations (0.5 to 10 mg/liter), fluconazole reached cell-associated concentrations greater than the extracellular ones in either human PMNs (intracellular concentration to extracellular concentration ratio, > or = 2.2) or McCoy cells (intracellular concentration to extracellular concentration ratio, > or = 1.3). The uptake of fluconazole by PMNs was rapid and reversible but was not energy dependent. The intracellular penetration of fluconazole was not affected by environmental pH or temperature. Ingestion of opsonized zymosan and opsonized Candida albicans did not significantly increase the amount of PMN-associated fluconazole. At therapeutic extracellular concentrations, the intracellular activity of fluconazole against C. albicans in PMNs was significantly lower than that of amphotericin B. It was concluded that fluconazole reaches high intracellular concentrations within PMNs but shows moderate activity against intracellular C. albicans in vitro. PMID:8452347

  10. Responses of Ulva prolifera to short-term nutrient enrichment under light and dark conditions

    NASA Astrophysics Data System (ADS)

    Sun, Kai-Ming; Li, Ruixiang; Li, Yan; Xin, Ming; Xiao, Jie; Wang, Zongling; Tang, Xuexi; Pang, Min

    2015-09-01

    To define responses of short-term nutrient uptake in Ulva prolifera, we measured uptake rates, enzyme activity, and tissue nutrient content in lab experiments where we manipulated nutrient supply and irradiation. Nitrate uptake of U. prolifera was significantly impacted by the external nitrate concentrations, and ammonium uptake was mainly determined by the light availability. The measured nitrogen contents in tissues were higher than the calculated values from the uptake of dissolve inorganic nitrogen, indicating that U. prolifera might use multiple nitrogen sources. High external phosphate concentrations and sufficient light can accelerate the phosphate uptake of U. prolifera, while the measured phosphorus contents in tissues were lower than the calculated values from the uptake of phosphate, suggesting a possibility of internal phosphorus release. The enzymatic activities of nitrate reductase (NR), acid phosphatase (AcP) and alkaline phosphatase (AP) showed little changes, indicating that enzymatic activity might not a direct factor determining the short-term nutrient uptake of U. prolifera.

  11. Nutrient Limitation Dynamics of a Coastal Cape Cod Pond: Seasonal Trends in Alkaline Phosphatase Activity

    DTIC Science & Technology

    2000-11-13

    106C: 16N: 1P) and alkaline phosphatase activity (APA) were utilized in tandem as nutrient deficiency indicators (NDIs) for phytoplankton . The study...nutrient enrichment incubation re-affirmed the use of APA as a robust indicator of phosphate limitation in phytoplankton . APA data indicate that the system...nutrient deficiency indicators (NDIs) for phytoplankton . The study objective was to evaluate the limiting nutrient status of the pond throughout the

  12. Interaction of Eu(III) with mammalian cells: Cytotoxicity, uptake, and speciation as a function of Eu(III) concentration and nutrient composition.

    PubMed

    Sachs, Susanne; Heller, Anne; Weiss, Stephan; Bok, Frank; Bernhard, Gert

    2015-10-01

    In case of the release of lanthanides and actinides into the environment, knowledge about their behavior in biological systems is necessary to assess and prevent adverse health effects for humans. We investigated the interaction of europium with FaDu cells (human squamous cell carcinoma cell line) combining analytical methods, spectroscopy, and thermodynamic modeling with in-vitro cell experiments under defined conditions. Both the cytotoxicity of Eu(III) onto FaDu cells and its cellular uptake are mainly concentration-dependent. Moreover, they are governed by its chemical speciation in the nutrient medium. In complete cell culture medium, i.e., in the presence of fetal bovine serum, Eu(III) is stabilized in solution in a wide concentration range by complexation with serum proteins resulting in low cytotoxicity and cellular Eu(III) uptake. In serum-free medium, Eu(III) precipitates as hardly soluble phosphate species, exhibiting a significantly higher cytotoxicity and slightly higher cellular uptake. The presence of a tenfold excess of citrate in serum-free medium causes the formation of Eu(HCit)2(3-) complexes in addition to the dominating Eu(III) phosphate species, resulting in a decreased Eu(III) cytotoxicity and cellular uptake. The results of this study underline the crucial role of a metal ion's speciation for its toxicity and bioavailability.

  13. Comparison of mineral weathering and biomass nutrient uptake in two small forested watersheds underlain by quartzite bedrock, Catoctin Mountain, Maryland, USA

    USGS Publications Warehouse

    Rice, Karen; Price, Jason R.

    2014-01-01

    To quantify chemical weathering and biological uptake, mass-balance calculations were performed on two small forested watersheds located in the Blue Ridge Physiographic Province in north-central Maryland, USA. Both watersheds, Bear Branch (BB) and Fishing Creek Tributary (FCT), are underlain by relatively unreactive quartzite bedrock. Such unreactive bedrock and associated low chemical-weathering rates offer the opportunity to quantify biological processes operating within the watershed. Hydrologic and stream-water chemistry data were collected from the two watersheds for the 9-year period from June 1, 1990 to May 31, 1999. Of the two watersheds, FCT exhibited both higher chemical-weathering rates and biomass nutrient uptake rates, suggesting that forest biomass aggradation was limited by the rate of chemical weathering of the bedrock. Although the chemical-weathering rate in the FCT watershed was low relative to the global average, it masked the influence of biomass base-cation uptake on stream-water chemistry. Any differences in bedrock mineralogy between the two watersheds did not exert a significant influence on the overall weathering stoichiometry. The difference in chemical-weathering rates between the two watersheds is best explained by a larger proportion of reactive phyllitic layers within the bedrock of the FCT watershed. Although the stream gradient of BB is about two-times greater than that of FCT, its influence on chemical weathering appears to be negligible. The findings of this study support the biomass nutrient uptake stoichiometry of K1.0Mg1.1Ca0.97 previously determined for the study site. Investigations of the chemical weathering of relatively unreactive quartzite bedrock may provide insight into critical zone processes.

  14. Prospects for optimizing soil microbial functioning to improve plant nutrient uptake and soil carbon sequestration under elevated CO2

    NASA Astrophysics Data System (ADS)

    Nie, M.; Pendall, E. G.

    2013-12-01

    Potential to mitigate climate change through increasing plant productivity and its carbon (C) input to soil may be limited by soil nitrogen (N) availability. Using a novel 13C-CO2 and 15N-soil dual labeling method, we investigated whether plant growth-promoting bacteria would interact with atmospheric CO2 concentration to alter plant productivity and soil C storage. We grew Bouteloua gracilis under ambient (380 ppm) or elevated CO2 (700 ppm) in climate-controlled chambers, and plant individuals were grown with or without Pseudomonas fluorescens inoculum, which can produce N catabolic enzymes. We observed that both eCO2 and P. fluorescens increased plant productivity and its C allocation to soil. P. fluorescens relative to eCO2 enhanced plant N uptake from soil organic matter, which highly correlated with soil N enzyme activities and rhizosphere exudate C. More importantly, P. fluorescens increased microbial biomass and deceased specific microbial respiration in comparison with eCO2. These results indicate that application of plant growth-promoting bacteria can increase microbial C utilization efficiency with subsequent N mineralization from soil organic matter, and may improve plant N availability and soil C sequestration. Together, our findings highlight the potential of plant growth-promoting bacteria for global change mitigation by terrestrial ecosystems.

  15. Dynamics of plant nutrients, utilization and uptake, and soil microbial community in crops under ambient and elevated carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In natural settings such as under field conditions, the plant available soil nutrients in conjunction with other environmental factors such as, solar radiation, temperature, precipitation, and atmospheric carbon dioxide (CO2) concentration determine crop adaptation and productivity. Therefore, crop...

  16. Magnetic field effect on growth, arsenic uptake, and total amylolytic activity on mesquite (Prosopis juliflora x P. velutina) seeds

    NASA Astrophysics Data System (ADS)

    Flores-Tavizón, Edith; Mokgalaka-Matlala, Ntebogeng S.; Elizalde Galindo, José T.; Castillo-Michelle, Hiram; Peralta-Videa, Jose R.; Gardea-Torresdey, Jorge L.

    2012-04-01

    Magnetic field is closely related to the cell metabolism of plants [N. A. Belyavskaya, Adv. Space Res. 34, 1566 (2004)]. In order to see the effect of magnetic field on the plant growth, arsenic uptake, and total amylolytic activity of mesquite (Prosopis juliflora x P. velutina) seeds, ten sets of 80 seeds were selected to be oriented with the long axis parallel or randomly oriented to an external magnetic field. The external magnetic field magnitude was 1 T, and the exposition time t = 30 min. Then, the seeds were stored for three days in a plastic bag and then sown on paper towels in a modified Hoagland's nutrient solution. After three days of germination in the dark and three days in light, seedlings were grown hydroponically in modified Hoagland's nutrient solution (high PO42-) containing 0, 10, or 20 ppm of arsenic as As (III) and (V). The results show that the germination ratios, growth, elongation, arsenic uptake, and total amylolytic activity of the long axis oriented mesquite seeds were much higher than those of the randomly oriented seeds. Also, these two sets of seeds showed higher properties than the ones that were not exposed to external magnetic field.

  17. Growth and nitrogen uptake by Salicornia europaea and Aster tripolium in nutrient conditions typical of aquaculture wastewater.

    PubMed

    Quintã, R; Santos, R; Thomas, D N; Le Vay, L

    2015-02-01

    The increasing need for environmentally sound aquaculture development can, in part, be addressed by using halophytic plants in integrated multitrophic aquaculture systems (IMTA) to remove waste dissolved nitrogen (N). However, knowledge of plant ability to take up nitrogen is of foremost importance to predict plants performance in such systems. Two species, Salicornia europaea and Aster tripolium, have been identified as potential candidates for IMTA due to their salt tolerance, potential N removal capabilities and their high commercial value as an additional crop. This study investigated the growth and N uptake rates of these two species under different N supply (NH4(+), NO3(-), NH4NO3). S. europaea plants produced a lower biomass when grown in NH4(+) compared to NO3(-) or NH4NO3, while A. tripolium biomass was not affected by the form in which N was supplied. N uptake in plants incubated at different concentrations of (15)N enriched solution (up to 2 mmol l(-1)) fitted the Michaelis-Menten model. While S. europaea NH4-N maximum uptake did not differ between starved and non-starved plants, A. tripolium NH4-N uptake was higher in starved plants when supplied alone. When NO3(-) was supplied alone, NO3-N maximum uptake was lower, for both species, when the plants were not starved. Comparison of starved and non-starved plants N uptake demonstrates the need for cautious interpretation of N uptake rates across different conditions. According to the observed results, both S. europaea and A. tripolium are capable of significantly high biomass production and N removal making them potential species for inclusion in efficient IMTA.

  18. Effects of anaerobic growth conditions on biomass accumulation, root morphology, and efficiencies of nutrient uptake and utilization in seedlings of some southern coastal plain

    SciTech Connect

    Topa, M.A.

    1984-01-01

    Seedlings of pond, and loblolly pines were grown in a non-circulating, continuously-flowing solution culture under anaerobic (0.75 mg/1 O/sub 2/) conditions to determine the effects of anaerobiosis on overall growth, root morphology and efficiencies of nutrient uptake and utilization. Although shoot growth of the 11-week old loblolly and pond was not affected by anaerobic treatment, it did significantly reduce root biomass. Sand pine suffered the largest biomass reduction. Flooding tolerance was positively correlated with morphological changes which enhanced root internal aeration. Oxygen transport from shoot to the root was demonstrated via rhizosphere oxidation experiments using indigo-carmine dye solutions and polarography. Stem and root collar lenticels were found to be the major sites of atmospheric O/sub 2/ entry for submerged roots. Longitudinal and radial pathways for gas diffusion via intercellular spaces in the pericycle and ray parenchyma, respectively, were elucidated histologically. Lenticel and aerenchyma development, and rhizosphere oxidation in roots of anaerobically-grown sand pine seedlings were minimal. Elemental analyses showed that anaerobic conditions interfered with nutrient absorption and utilization. Short-term /sup 32/P uptake experiments with intact seedlings indicated that net absorption decreased because of the reduction in root biomass. Phosphorus absorption rates were negatively correlated with internal tissue phosphorus concentrations, and root and shoot biomass. 315 refs., 25 figs., 14 tabs.

  19. Active Layer Soil Carbon and Nutrient Mineralization, Barrow, Alaska, 2012

    DOE Data Explorer

    Stan D. Wullschleger; Holly M. Vander Stel; Colleen Iversen; Victoria L. Sloan; Richard J. Norby; Mallory P. Ladd; Jason K. Keller; Ariane Jong; Joanne Childs; Deanne J. Brice

    2015-10-29

    This data set consists of bulk soil characteristics as well as carbon and nutrient mineralization rates of active layer soils manually collected from the field in August, 2012, frozen, and then thawed and incubated across a range of temperatures in the laboratory for 28 day periods in 2013-2015. The soils were collected from four replicate polygons in each of the four Areas (A, B, C, and D) of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Soil samples were coincident with the established Vegetation Plots that are located in center, edge, and trough microtopography in each polygon. Data included are 1) bulk soil characteristics including carbon, nitrogen, gravimetric water content, bulk density, and pH in 5-cm depth increments and also by soil horizon, 2) carbon, nitrogen, and phosphorus mineralization rates for soil horizons incubated aerobically (and in one case both aerobically and anaerobically) for 28 days at temperatures that included 2, 4, 8, and 12 degrees C. Additional soil and incubation data are forthcoming. They will be available when published as part of another paper that includes additional replicate analyses.

  20. Silicate mineral impacts on the uptake and storage of arsenic and plant nutrients in rice ( Oryza sativa L.).

    PubMed

    Seyfferth, Angelia L; Fendorf, Scott

    2012-12-18

    Arsenic-contaminated rice grain may threaten human health globally. Since H₃AsO₃⁰ is the predominant As species found in paddy pore-waters, and H₄SiO₄⁰ and H₃AsO₃⁰ share an uptake pathway, silica amendments have been proposed to decrease As uptake and consequent As concentrations in grains. Here, we evaluated the impact of two silicate mineral additions differing in solubility (+Si(L), diatomaceous earth, 0.29 mM Si; +Si(H), Si-gel, 1.1 mM Si) to soils differing in mineralogy on arsenic concentration in rice. The +Si(L) addition either did not change or decreased As concentration in pore-water but did not change or increased grain-As levels relative to the (+As--Si) control. The +Si(H) addition increased As in pore-water, but it significantly decreased grain-As relative to the (+As--Si) control. Only the +Si(H) addition resulted in significant increases in straw- and husk-Si. Total grain- and straw-As was negatively correlated with pore-water Si, and the relationship differed between two soils exhibiting different mineralogy. These differing results are a consequence of competition between H₄SiO₄⁰ and H₃AsO₃⁰ for adsorption sites on soil solids and subsequent plant-uptake, and illustrate the importance of Si mineralogy on arsenic uptake.

  1. Fertilizer and soil management practices for improving the efficiency of nutrient uptake and use in northern highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highbush blueberry is a long-lived perennial crop well-adapted to acidic soils. Plants acquire primarily NH4-N and tolerate relatively low concentrations of P and cations in the soil and high concentrations of plant available metals such as Al and Mn. Recently, we found that optimal leaf nutrient co...

  2. Juglone disrupts root plasma membrane H+-ATPase activity and impairs water uptake, root respiration, and growth in soybean (Glycine max) and corn (Zea mays).

    PubMed

    Hejl, Angela M; Koster, Karen L

    2004-02-01

    Juglone is phytotoxic, but the mechanisms of growth inhibition have not been fully explained. Previous studies have proposed that disruption of electron transport functions in mitochondria and chloroplasts contribute to observed growth reduction in species exposed to juglone. In studies reported here, corn and soybean seedlings grown in nutrient solution amended with 10, 50, or 100 microM juglone showed significant decreases in root and shoot dry weights and lengths with increasing concentrations. However, no significant differences in leaf chlorophyll fluorescence or CO2-dependent leaf oxygen evolution were observed, even in seedlings that were visibly affected. Disruption of root oxygen uptake was positively correlated with increasing concentrations of juglone, suggesting that juglone may reach mitochondria in root cells. Water uptake and acid efflux also decreased for corn and soybean seedlings treated with juglone, suggesting that juglone may affect metabolism of root cells by disrupting root plasma membrane function. Therefore, the effect of juglone on H+-ATPase activity in corn and soybean root microsomes was tested. Juglone treatments from 10 to 1000 microM significantly reduced H+-ATPase activity compared to controls. This inhibition of H+-ATPase activity and observed reduction of water uptake offers a logical explanation for previously documented phytotoxicity of juglone. Impairment of this enzyme's activity could affect plant growth in a number of ways because proton-pumping in root cells drives essential plant processes such as solute uptake and, hence, water uptake.

  3. Effects of a controlled-release fertilizer on yield, nutrient uptake, and fertilizer usage efficiency in early ripening rapeseed (Brassica napus L.)*

    PubMed Central

    Tian, Chang; Zhou, Xuan; Liu, Qiang; Peng, Jian-wei; Wang, Wen-ming; Zhang, Zhen-hua; Yang, Yong; Song, Hai-xing; Guan, Chun-yun

    2016-01-01

    Background: Nitrogen (N), phosphorous (P), and potassium (K) are critical nutrient elements necessary for crop plant growth and development. However, excessive inputs will lead to inefficient usage and cause excessive nutrient losses in the field environment, and also adversely affect the soil, water and air quality, human health, and biodiversity. Methods: Field experiments were conducted to study the effects of controlled-release fertilizer (CRF) on seed yield, plant growth, nutrient uptake, and fertilizer usage efficiency for early ripening rapeseed (Xiangzayou 1613) in the red-yellow soil of southern China during 2011–2013. It was grown using a soluble fertilizer (SF) and the same amounts of CRF, such as SF1/CRF1 (3750 kg/hm2), SF2/CRF2 (3000 kg/hm2), SF3/CRF3 (2250 kg/hm2), SF4/CRF4 (1500 kg/hm2), SF5/CRF5 (750 kg/hm2), and also using no fertilizer (CK). Results: CRF gave higher seed yields than SF in both seasons by 14.51%. CRF4 and SF3 in each group achieved maximum seed yield (2066.97 and 1844.50 kg/hm2, respectively), followed by CRF3 (1929.97 kg/hm2) and SF4 (1839.40 kg/hm2). There were no significant differences in seed yield among CK, SF1, and CRF1 (P>0.05). CRF4 had the highest profit (7126.4 CNY/hm2) and showed an increase of 12.37% in seed yield, and it decreased by 11.01% in unit fertilizer rate compared with SF4. The branch number, pod number, and dry matter weight compared with SF increased significantly under the fertilization of CRF (P<0.05). The pod number per plant was the major contributor to seed yield. On the other hand, the N, P, and K uptakes increased at first and then decreased with increasing the fertilizer rate at maturity, and the N, P, and K usage efficiency decreased with increasing the fertilizer rate. The N, P, and K uptakes and usage efficiencies of the CRF were significantly higher than those of SF (P<0.05). The N accumulation and N usage efficiency of CRF increased by an average of 13.66% and 9.74 percentage points

  4. [Effects of reduced N application rate on yield and nutrient uptake and utilization in maize-soybean relay strip intercropping system].

    PubMed

    Yong, Tai-Wen; Liu, Xiao-Ming; Wen-Yu, Liu; Su, Ben-Ying; Song, Chun; Yang, Feng; Wang, Xiao-Chun; Yang, Wen-Yu

    2014-02-01

    A field experiment with three N application rates (0, 180, 240 N kg x hm(-2), representing zero, reduced and conventional N application, respectively) and three planting patterns (maize monoculture, soybean monoculture and maize-soybean relay strip intercropping) was conducted to reveal the effects of cropping patterns and N application rates on yield, nutrient uptake and nitrogen use efficiency of maize and soybean. The results showed that the grain yield, N, P and K uptake and harvest index of the intercropped maize reduced slightly compared with the monoculture maize, however these indices of the intercropped soybean increased significantly compared with the monoculture. With the increase in nitrogen fertilizer application, the excellence of relay strip intercropping was weakened in the maize-soybean intercropping system. The grain yield, economic coefficient, N, P and K uptake, harvest index, N agronomy efficiency and N uptake efficiency of maize and soybean increased significantly at the reduced nitrogen rate (180 N kg x hm(-2)), but the rate of soil N contribution declined, compared with the conventional rate of N application by local farmers (240 N kg x hm(-2)). In the reduced nitrogen rate treatment, total soil N and P contents of the maize strip reduced, whereas the total soil N, P and K contents of soybean strip and the total K content of maize strip increased compared with the zero N application treatment. With the reduced N application, the annual total grain yield, N, P and K uptake of above-ground biomass in the maize-soybean relay strip intercropping system were higher than in the monoculture, and the land equivalent ratio (LER) was 2.28. N uptake efficiency of maize in the relay strip intercropping system was 20.2% higher than in the maize monoculture, and the index of soybean was 30.5% lower than in the monoculture. The rate of soil N contribution in the relay strip intercropping system was 20.0% and 8.8% lower than in the maize and soybean

  5. 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

  6. A Transmissible Plant Shoot Factor Promotes Uptake Hydrogenase Activity in Rhizobium Symbionts 1

    PubMed Central

    Bedmar, Eulogio J.; Phillips, Donald A.

    1984-01-01

    Shoot/root grafting studies showed organ and host cultivar effects on net H2 evolution from Pisum sativum L. root nodules. Net H2 evolution from those nodules represents the sum of H2 formed by Rhizobium nitrogenase and H2 oxidized by any uptake hydrogenase present in the bacteria. Grafts between pea cultivars `JI1205' or `Alaska' and `Feltham First' in symbioses with R. leguminosarum 128C53 showed that shoots of both JI1205 and Alaska increased H2 uptake significantly (P ≤ 0.05) in Feltham First root nodules. The same plants also had less net H2 evolution at similar rates of C2H2 reduction than plants formed by grafting Feltham First shoots on Feltham First roots. Although JI1205 and Alaska shoots increased H2-uptake activity of Feltham First root nodules 28 days after the graft was made, intermediate to high levels of H2 uptake activity were still present in nodules on roots of both JI1205 and Alaska grafted to Feltham First shoots. These results indicate the presence of a transmissible shoot factor(s) which can increase uptake hydrogenase activity in a Rhizobium symbiont and show that root genotype also can influence that parameter. Parallel grafting experiments using the same pea cultivars in symbioses with R. leguminosarum strain 300, which lacks uptake hydrogenase activity, suggested that a transmissible shoot factor(s) altered H2 formation from nitrogenase by changing the electron allocation coefficient of that enzyme complex. The root and shoot factor(s) detected in this study had no permanent effect on strain 128C53. Bacterial cells isolated from Feltham First nodules with low H2 uptake activity formed root nodules on JI1205 and Alaska with high H2 uptake activity. Bacteroids isolated from nodules on intact JI1205, Alaska, or Feltham First plants with high, medium, or low H2 uptake activity, respectively, maintained those phenotypes during in vitro assays. PMID:16663677

  7. A transmissible plant shoot factor promotes uptake hydrogenase activity in Rhizobium symbionts.

    PubMed

    Bedmar, E J; Phillips, D A

    1984-07-01

    Shoot/root grafting studies showed organ and host cultivar effects on net H(2) evolution from Pisum sativum L. root nodules. Net H(2) evolution from those nodules represents the sum of H(2) formed by Rhizobium nitrogenase and H(2) oxidized by any uptake hydrogenase present in the bacteria. Grafts between pea cultivars ;JI1205' or ;Alaska' and ;Feltham First' in symbioses with R. leguminosarum 128C53 showed that shoots of both JI1205 and Alaska increased H(2) uptake significantly (P uptake activity of Feltham First root nodules 28 days after the graft was made, intermediate to high levels of H(2) uptake activity were still present in nodules on roots of both JI1205 and Alaska grafted to Feltham First shoots. These results indicate the presence of a transmissible shoot factor(s) which can increase uptake hydrogenase activity in a Rhizobium symbiont and show that root genotype also can influence that parameter.Parallel grafting experiments using the same pea cultivars in symbioses with R. leguminosarum strain 300, which lacks uptake hydrogenase activity, suggested that a transmissible shoot factor(s) altered H(2) formation from nitrogenase by changing the electron allocation coefficient of that enzyme complex.The root and shoot factor(s) detected in this study had no permanent effect on strain 128C53. Bacterial cells isolated from Feltham First nodules with low H(2) uptake activity formed root nodules on JI1205 and Alaska with high H(2) uptake activity. Bacteroids isolated from nodules on intact JI1205, Alaska, or Feltham First plants with high, medium, or low H(2) uptake activity, respectively, maintained those phenotypes during in vitro assays.

  8. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  9. Functional traits and structural controls on the relationship between photosynthetic CO2 uptake and sun-induced fluorescence in a Mediterranean grassland under different nutrient availability

    NASA Astrophysics Data System (ADS)

    Migliavacca, Mirco

    2016-04-01

    Recent studies have shown how human induced nitrogen (N) and phosphorous (P) imbalances affect essential ecosystem processes, and might be particularly important in water-limited ecosystems. Hyperspectral information can be used to directly infer nutrient-induced variation in structural and functional changes of vegetation under different nutrient availability. However, several uncertainties still hamper the direct link between photosynthetic CO2 uptake (gross primary productivity, GPP) and hyperspectral reflectance. Sun-induced fluorescence (SIF) provides a new non-invasive measurement approach that has the potential to quantify dynamic changes in light use efficiency and photosynthetic CO2 uptake. In this contribution we will present an experiment conducted in a Mediterranean grassland, where 16 plots of 8x8 meters were manipulated by adding nutrient (N, P, and NP). Almost simultaneous estimates of canopy scale GPP and SIF were conducted with transparent transient-state canopy chambers and high resolution spectrometers, respectively. We investigated the response of GPP and SIF to different nutrient availability and plant stoichiometry. The second objective was to identify how structural (LAI, leaf angle distribution, and biodiversity) and canopy biochemical properties (e.g. N and chlorophyll content - Chl) control the functional relationship between GPP and SIF. To test the different hypotheses the SCOPE radiative transfer model was used. We ran a factorial experiment with SCOPE to disentangle the main drivers (structure vs biochemistry) of the relationship GPP-SIF. The results showed significant differences in GPP values between N and without N addition plots. We also found that vegetation indices sensitive to pigment variations and physiology (such as photochemical reflectance index PRI) and SIF showed differences between different treatments. SCOPE showed very good agreement with the observed data (R2=0.71). The observed variability in SIF was mainly related

  10. Sorptive uptake of selenium with magnetite and its supported materials onto activated carbon.

    PubMed

    Kwon, Jae H; Wilson, Lee D; Sammynaiken, R

    2015-11-01

    Kinetic and equilibrium uptake studies of selenite in aqueous solution with synthetic magnetite (Mag-P), commercial magnetite (Mag-C), goethite, activated carbon (AC), and a composite material containing 19% magnetite supported on activated carbon (CM-19) were investigated. Kinetic uptake studies used a one-pot setup at pH 5.26 at variable temperature. Sampling of unbound selenite in-situ was achieved with analytical detection by atomic absorbance. The sorptive uptake at equilibrium and kinetic conditions are listed in descending order: goethite>Mag-P>Mag-C>CM-19. Kinetic uptake parameters reveal that Mag-P showed apparent negative values for the activation energy (E(a)) and the enthalpy of activation (ΔH(‡)), in agreement with a multi-step process for the kinetic uptake of selenite. By contrast, Mag-C, CM-19, and goethite showed positive values for E(a) and ΔH(‡). The uptake properties of the various sorbent materials with selenite are in accordance with the formation of inner- and out-sphere complexes. Leaching of iron from the composite material (CM-19) was attenuated due to the stabilizing effect of the magnetite within the pore sites and the surface of AC. Supported iron oxide nanomaterial composites represent a unique sorbent material with tunable uptake properties toward inorganic selenite in aqueous solution.

  11. Thyroid function in fasting rats: variations in 131I uptake and transient decrease in peroxidase activity.

    PubMed

    Moura, E G; Ramos, C F; Nascimento, C C; Rosenthal, D; Breitenbach, M M

    1987-01-01

    Serum thyroxine and triiodothyronine, radioiodide thyroid uptake and thyroid peroxidase (TPO) activity were studied over a 2 to 5 day period in fasting rats treated (F+) or not (F-) with TSH. In F- rats, TPO activity was transiently decreased on the 3rd day, whereas in F+ it was always higher than in controls. On the 5th day, the 2 h thyroid uptake of 131I decreased in F-, while the 24 h uptake increased in both F- and F+. Serum T3 and T4 decreased in both fasting groups. Thus, not all effects of fasting on rat thyroid function are reverted by TSH administration, suggesting intrinsic impairment of glandular function.

  12. Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

    PubMed

    Liu, Junzhuo; Vyverman, Wim

    2015-03-01

    The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio.

  13. Sediment Microbial Enzyme Activity as an Indicator of Nutrient Limitation in Great Lakes Coastal Wetlands

    EPA Science Inventory

    This study, the first to link microbial enzyme activities to regional-scale anthropogenic stressors, suggests that microbial enzyme regulation of carbon and nutrient dynamics may be sensitive indicators of nutrient dynamics in aquatic ecosystems, but further work is needed to elu...

  14. Silicon uptake and transport is an active process in Cucumis sativus.

    PubMed

    Liang, Yongchao; Si, Jin; Römheld, Volker

    2005-09-01

    Cucumis sativus is a species known to accumulate high levels of silicon (Si) in the tops, though the mechanism for its high Si uptake is little understood. In a series of hydroponic experiments, we examined uptake and xylem loading of Si in C. sativus along with Vicia faba at three levels of Si (0.085, 0.17 and 1.70 mm). Measured Si uptake in C. sativus was more than twice as high as calculated from the rate of transpiration assuming no discrimination between silicic acid and water in uptake. Measured Si uptake in V. faba, however, was significantly lower than the calculated uptake. Concentration of Si in xylem exudates was several-fold higher in C. sativus, but was significantly lower in V. faba compared with the Si concentration in external solutions, regardless of Si levels. Silicon uptake was strongly inhibited by low temperature and 2,4-dinitrophenol, a metabolic inhibitor, in C. sativus but not in V. faba. It can be concluded that Si uptake and transport in C. sativus is active and independent of external Si concentrations, in contrast to the process in V. faba.

  15. Effects of In-stream Restorations on Stream Hydrodynamics, Nutrient Uptake, and Ecosystem Metabolism at Fort Benning, GA

    NASA Astrophysics Data System (ADS)

    Roberts, B. J.; Mulholland, P. J.

    2005-05-01

    Spatial variability in military training intensity results in a wide range of upland disturbance intensity at the Fort Benning Military Reservation (near Columbus, GA). We selected stream reaches within 8 catchments with contrasting levels of upland denudation and stream ecosystem disturbance. In October 2003, 4 of these streams (spanning the disturbance gradient) received in-stream restorations in the form of coarse woody debris dams every 10 m for the 100 m study reaches. Stream hydrodynamic properties, NH4+ uptake, and whole-stream metabolism were examined both prior to and after restoration for all 8 streams. In-stream restorations resulted in increases in the relative size of transient storage zones (important for biological processes) and spatial variation in water velocity (enhances habitat variability). These hydrodynamic changes corresponded to increases in both NH4+ uptake rate and velocity as the ability of stream biota to control stream NH4+ concentration increased. By monitoring stream metabolism rates for two years prior to restoration we are able to assess the impact of the restorations on these important integrative processes using a BACI-type analysis (before-after control-treatment analysis) for the first year of post-restoration.

  16. Effect of Off-Season Flooding on Growth, Photosynthesis, Carbohydrate Partitioning, and Nutrient Uptake in Distylium chinense

    PubMed Central

    Liu, Zebin; Cheng, Ruimei; Xiao, Wenfa; Guo, Quanshui; Wang, Na

    2014-01-01

    Distylium chinense is an evergreen shrub used for the vegetation recovery of floodplain and riparian areas in Three Gorges Reservoir Region. To clarify the morphological and physiological responses and tolerance of Distylium chinense to off-season flooding, a simulation flooding experiment was conducted during autumn and winter. Results indicated that the survival rate of seedlings was 100%, and that plant height and stem diameter were not significantly affected by flooding. Adventitious roots and hypertrophic lenticels were observed in flooded seedlings after 30 days of flooding. Flooding significantly reduced the plant biomass of roots, net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm), photochemical quenching (qP), and electron transport rate (ETR) in leaves, and also affected the allocation and transport of carbohydrate and nutrients. However, D. chinense was able to maintain stable levels of Pn, Fv/Fm, qP, ETR, and nutrient content (N and P) in leaves and to store a certain amount of carbohydrate in roots over prolonged durations of flooding. Based on these results, we conclude that there is a high flooding tolerance in D. chinense, and the high survival rate of D. chinense may be attributable to a combination of morphological and physiological responses to flooding. PMID:25222006

  17. Arbuscular mycorrhizal fungi increased growth, nutrient uptake and tolerance to salinity in olive trees under nursery conditions.

    PubMed

    Porras-Soriano, Andrés; Soriano-Martín, María Luisa; Porras-Piedra, Andrés; Azcón, Rosario

    2009-09-01

    Inoculating olive plantlets with the arbuscular mycorrhizal fungi (AMF) Glomus mosseae, Glomus intraradices or Glomus claroideum increased plant growth and the ability to acquire nitrogen, phosphorus, and potassium from non-saline as well as saline media. AMF-colonized plants also increased in survival rate after transplant. Osmotic stress caused by NaCl supply reduced stem diameter, number of shoots, shoot length and nutrients in olive plants, but AMF colonization alleviated all of these negative effects on growth. G. mosseae was the most efficient fungus in reducing the detrimental effects of salinity; it increased shoot growth by 163% and root growth by 295% in the non-saline medium, and by 239% (shoot) and by 468% (root) under the saline conditions. AMF colonization enhanced salt tolerance in terms of olive growth and nutrient acquisition. Mycorrhizal olive plants showed the lowest biomass reduction under salinity (34%), while growth was reduced by 78% in control plants. This G. mosseae effect seems to be due to increased K acquisition; K content was enhanced under salt conditions by 6.4-fold with G. mosseae, 3.4-fold with G. intraradices, and 3.7-fold with G. claroideum. Potassium, as the most prominent inorganic solute, plays a key role in the osmoregulation processes and the highest salinity tolerance of G. mosseae-colonized olive trees was concomitant with an enhanced K concentration in olive plants.

  18. 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.

  19. Multiple AMPK activators inhibit L-Carnitine uptake in C2C12 skeletal muscle myotubes.

    PubMed

    Shaw, Andy; Jeromson, Stewart; Watterson, Kenneth R; Pediani, John D; Gallagher, Iain; Whalley, Tim; Dreczkowski, Gillian; Brooks, Naomi; Galloway, Stuart; Hamilton, D Lee

    2017-03-15

    Mutations in the gene that encodes the principal L-Carnitine transporter, OCTN2, can lead to a reduced intracellular L-Carnitine pool and the disease Primary Carnitine Deficiency. L-Carnitine supplementation is used therapeutically to increase intracellular L-Carnitine. As AMPK and insulin regulate fat metabolism and substrate uptake we hypothesised that AMPK activating compounds and insulin would increase L-Carnitine uptake in C2C12 myotubes. The cells express all three OCTN transporters at the mRNA level and immunohistochemistry confirmed expression at the protein level. Contrary to our hypothesis, despite significant activation of PKB and 2DG uptake, insulin did not increase L-Carnitine uptake at 100nM. However, L-Carnitine uptake was modestly increased at a dose of 150nM insulin. A range of AMPK activators that increase intracellular calcium content [caffeine (10mM, 5mM, 1mM, 0.5mM), A23187 (10μM)], inhibit mitochondrial function [Sodium Azide (75μM), Rotenone (1μM), Berberine (100μM), DNP (500μM)] or directly activate AMPK [AICAR (250μM)] were assessed for their ability to regulate L-Carnitine uptake. All compounds tested significantly inhibited L-Carnitine uptake. Inhibition by caffeine was not dantrolene (10μM) sensitive. Saturation curve analysis suggested that caffeine did not competitively inhibit L-Carnitine transport. However, the AMPK inhibitor Compound C (10μM) partially rescued the effect of caffeine suggesting that AMPK may play a role in the inhibitory effects of caffeine. However, caffeine likely inhibits L-Carnitine uptake by alternative mechanisms independently of calcium release. PKA activation or direct interference with transporter function may play a role.

  20. Ceruloplasmin ferroxidase activity stimulates cellular iron uptake by a trivalent cation-specific transport mechanism

    NASA Technical Reports Server (NTRS)

    Attieh, Z. K.; Mukhopadhyay, C. K.; Seshadri, V.; Tripoulas, N. A.; Fox, P. L.

    1999-01-01

    The balance required to maintain appropriate cellular and tissue iron levels has led to the evolution of multiple mechanisms to precisely regulate iron uptake from transferrin and low molecular weight iron chelates. A role for ceruloplasmin (Cp) in vertebrate iron metabolism is suggested by its potent ferroxidase activity catalyzing conversion of Fe2+ to Fe3+, by identification of yeast copper oxidases homologous to Cp that facilitate high affinity iron uptake, and by studies of "aceruloplasminemic" patients who have extensive iron deposits in multiple tissues. We have recently shown that Cp increases iron uptake by cultured HepG2 cells. In this report, we investigated the mechanism by which Cp stimulates cellular iron uptake. Cp stimulated the rate of non-transferrin 55Fe uptake by iron-deficient K562 cells by 2-3-fold, using a transferrin receptor-independent pathway. Induction of Cp-stimulated iron uptake by iron deficiency was blocked by actinomycin D and cycloheximide, consistent with a transcriptionally induced or regulated transporter. Cp-stimulated iron uptake was completely blocked by unlabeled Fe3+ and by other trivalent cations including Al3+, Ga3+, and Cr3+, but not by divalent cations. These results indicate that Cp utilizes a trivalent cation-specific transporter. Cp ferroxidase activity was required for iron uptake as shown by the ineffectiveness of two ferroxidase-deficient Cp preparations, copper-deficient Cp and thiomolybdate-treated Cp. We propose a model in which iron reduction and subsequent re-oxidation by Cp are essential for an iron uptake pathway with high ion specificity.

  1. Calcium uptake and ATPase activity of sarcoplasmic reticulum vesicles isolated from control and selenium deficient lambs.

    PubMed

    Tripp, M J; Whanger, P D; Schmitz, J A

    1993-06-01

    The calcium uptake and ATPase activity were studied using fragmented sarcoplasmic reticulum (FSR) vesicles from normal and selenium (vitamin E)--deficient lambs. The latter group was suffering from white muscle disease (WMD). The calcium uptake of FSR vesicles from muscle of WMD lambs was reduced 10-fold as compared to those from normal lambs. An inverse relationship was found with the calcium uptake ability of the FSR vesicles and the severity of WMD. ATPase activity was nonsignificantly lower in vesicles from WMD lambs. The most active FSR vesicles from both normal and WMD lambs banded at 27% when purified on linear sucrose density gradients. The number of protein bands appearing in acrylamide gels of the purified vesicles appeared to be directly proportional to the severity of WMD. The 75Se cosedimented with the calcium uptake and ATPase activity when FSR vesicles from a lamb injected with 75Se-selenite were subjected to linear sucrose density gradient centrifugation, suggesting that selenium is incorporated into these vesicles. Injection of selenium into WMD lambs resulted in significantly greater calcium uptake activity in vesicles 18 and 38 days later as compared with untreated WMD lambs. Injection of selenium in WMD lambs resulted in a marked decrease in plasma CPK activity and a significant increase of glutathione peroxidase activity in the blood.

  2. Nitrate Reductase Regulates Expression of Nitrite Uptake and Nitrite Reductase Activities in Chlamydomonas reinhardtii 1

    PubMed Central

    Galván, Aurora; Cárdenas, Jacobo; Fernández, Emilio

    1992-01-01

    In Chlamydomonas reinhardtii mutants defective at the structural locus for nitrate reductase (nit-1) or at loci for biosynthesis of the molybdopterin cofactor (nit-3, nit-4, or nit-5 and nit-6), both nitrite uptake and nitrite reductase activities were repressed in ammonium-grown cells and expressed at high amounts in nitrogen-free media or in media containing nitrate or nitrite. In contrast, wild-type cells required nitrate induction for expression of high levels of both activities. In mutants defective at the regulatory locus for nitrate reductase (nit-2), very low levels of nitrite uptake and nitrite reductase activities were expressed even in the presence of nitrate or nitrite. Both restoration of nitrate reductase activity in mutants defective at nit-1, nit-3, and nit-4 by isolating diploid strains among them and transformation of a structural mutant upon integration of the wild-type nit-1 gene gave rise to the wild-type expression pattern for nitrite uptake and nitrite reductase activities. Conversely, inactivation of nitrate reductase by tungstate treatment in nitrate, nitrite, or nitrogen-free media made wild-type cells respond like nitrate reductase-deficient mutants with respect to the expression of nitrite uptake and nitrite reductase activities. Our results indicate that nit-2 is a regulatory locus for both the nitrite uptake system and nitrite reductase, and that the nitrate reductase enzyme plays an important role in the regulation of the expression of both enzyme activities. PMID:16668656

  3. Effect of calcium carbonate on cadmium and nutrients uptake in tobacco (Nicotiana tabacum L.) planted on contaminated soil.

    PubMed

    Zeng, Wei-Ai; Li, Fan; Zhou, Hang; Qin, Xiao-Li; Zou, Zi-Jin; Tian, Tao; Zeng, Min; Liao, Bo-Han

    2016-01-01

    In the present study, calcium carbonate (CaCO3) was applied to Cd-contaminated soil at rates of 0, 0.5 and 1.0 g kg(-1). The effect of CaCO3 on soil pH, organic matter, available Cd, exchangeable Cd and level of major nutrients in a tobacco field and on accumulation of various elements in tobacco plants was determined. The results showed that CaCO3 application significantly increased the pH level, available P and exchangeable Ca but decreased organic matter, available Cd, exchangeable Cd, available heavy metals (Fe, Mn, Zn and Cu) and available K in soil. Additionally, CaCO3 application substantially reduced Cd accumulation in tobacco roots, stems, upper leaves, middle leaves and lower leaves, with maximum decrease of 22.3%, 32.1%, 24.5%, 22.0% and 18.2%, respectively. There were large increase in total Ca and slight increases in total N and K but decrease to varying degrees in total Fe, Cu and Zn due to CaCO3 application. CaCO3 had little effect on total P and Mn levels in tobacco leaves.

  4. Ultrasonic waste activated sludge disintegration for recovering multiple nutrients for biofuel production.

    PubMed

    Xie, Guo-Jun; Liu, Bing-Feng; Wang, Qilin; Ding, Jie; Ren, Nan-Qi

    2016-04-15

    Waste activated sludge is a valuable resource containing multiple nutrients, but is currently treated and disposed of as an important source of pollution. In this work, waste activated sludge after ultrasound pretreatment was reused as multiple nutrients for biofuel production. The nutrients trapped in sludge floc were transferred into liquid medium by ultrasonic disintegration during first 30 min, while further increase of pretreatment time only resulted in slight increase of nutrients release. Hydrogen production by Ethanoligenens harbinense B49 from glucose significantly increased with the concentration of ultrasonic sludge, and reached maximum yield of 1.97 mol H2/mol glucose at sludge concentration of 7.75 g volatile suspended solids/l. Without addition of any other chemicals, waste molasses rich in carbohydrate was efficiently turned into hydrogen with yield of 189.34 ml H2/g total sugar by E. harbinense B49 using ultrasonic sludge as nutrients. The results also showed that hydrogen production using pretreated sludge as multiple nutrients was higher than those using standard nutrients. Acetic acid produced by E. harbinense B49 together with the residual nutrients in the liquid medium were further converted into hydrogen (271.36 ml H2/g total sugar) by Rhodopseudomonas faecalis RLD-53 through photo fermentation, while ethanol was the sole end product with yield of 220.26 mg/g total sugar. Thus, pretreated sludge was an efficient nutrients source for biofuel production, which could replace the standard nutrients. This research provided a novel strategy to achieve environmental friendly sludge disposal and simultaneous efficient biofuel recovery from organic waste.

  5. Does FDG uptake measure proliferative activity of human cancer cells? In vitro comparison with DNA flow cytometry and tritiated thymidine uptake.

    PubMed

    Higashi, K; Clavo, A C; Wahl, R L

    1993-03-01

    The relationship between 3H-2-fluoro-2-deoxy-D-glucose (FDG) uptake and the proliferative rate of a human ovarian adenocarcinoma cell line (HTB77IP3) was examined in vitro. HTB77IP3 cells were plated and allowed to grow through lag, exponential and plateau phases. Proliferative rate assessed by DNA flow cytometry and 3H-thymidine incorporation was highest in the lag phase and fell significantly as the cells progressed from the exponential through plateau phases. By DNA flow cytometry, the proliferation index (% of S+G2/M phase cells) fell from 65% to 23%. Thymidine uptake per cell also declined, by 82%, from lag to plateau phase. By contrast, 3H-FDG uptake per cell was largely unchanged as the cells progressed through the cell growth cycle. Total 3H-FDG uptake was strongly correlated with the number of viable cancer cells present (r = 0.957). Total thymidine uptake, however, substantially underestimated the number of viable cancer cells present. These in vitro differences in tracer uptake suggest that in this adenocarcinoma cell line, FDG measures a substantially different parameter (viable cell number) than thymidine (proliferative rate) and that these differences may result in disparate findings on PET imaging of cancers using these two tracers. Our data for this in vitro system indicate that FDG uptake does not relate to the proliferative activity of cancer cells. However, FDG uptake is strongly related to the number of viable tumor cells.

  6. DHEA improves glucose uptake via activations of protein kinase C and phosphatidylinositol 3-kinase.

    PubMed

    Ishizuka, T; Kajita, K; Miura, A; Ishizawa, M; Kanoh, Y; Itaya, S; Kimura, M; Muto, N; Mune, T; Morita, H; Yasuda, K

    1999-01-01

    We have examined the effect of adrenal androgen, dehydroepiandrosterone (DHEA), on glucose uptake, phosphatidylinositol (PI) 3-kinase, and protein kinase C (PKC) activity in rat adipocytes. DHEA (1 microM) provoked a twofold increase in 2-[3H]deoxyglucose (DG) uptake for 30 min. Pretreatment with DHEA increased insulin-induced 2-[3H]DG uptake without alterations of insulin specific binding and autophosphorylation of insulin receptor. DHEA also stimulated PI 3-kinase activity. [3H]DHEA bound to purified PKC containing PKC-alpha, -beta, and -gamma. DHEA provoked the translocation of PKC-beta and -zeta from the cytosol to the membrane in rat adipocytes. These results suggest that DHEA stimulates both PI 3-kinase and PKCs and subsequently stimulates glucose uptake. Moreover, to clarify the in vivo effect of DHEA on Goto-Kakizaki (GK) and Otsuka Long-Evans fatty (OLETF) rats, animal models of non-insulin-dependent diabetes mellitus (NIDDM) were treated with 0.4% DHEA for 2 wk. Insulin- and 12-O-tetradecanoyl phorbol-13-acetate-induced 2-[3H]DG uptakes of adipocytes were significantly increased, but there was no significant increase in the soleus muscles in DHEA-treated GK/Wistar or OLETF/Long-Evans Tokushima (LETO) rats when compared with untreated GK/Wistar or OLETF/LETO rats. These results indicate that in vivo DHEA treatment can result in increased insulin-induced glucose uptake in two different NIDDM rat models.

  7. Nitrogen fertilizer enhances growth and nutrient uptake of Medicago sativa inoculated with Glomus tortuosum grown in Cd-contaminated acidic soil.

    PubMed

    Liu, Mohan; Sun, Jian; Li, Yang; Xiao, Yan

    2017-01-01

    This study aimed to explore whether nitrogen availability could influence mycorrhizal function and their associations with host plants in Cd-contaminated acidic soils or not. A greenhouse pot experiment was conducted to assess the effects of mycorrhizal inoculation (non-mycorrhizal inoculation (NM), Glomus aggregatum (Ga), G. tortuosum (Gt) and G. versiforme (Gv)) and inorganic N amendment on the growth, nutrient and Cd uptake of Medicago sativa grown in Cd-contaminated acidic soils (10 mg Cd kg(-1) soil). AMF inoculations significantly increased the shoot and total biomass and decreased the shoot Cd concentration in comparison to plants uninoculated. N addition increased markedly concentration and content of N and decreased those of P in plants at all inoculation treatments. Shoot K, Na and Mg concentration in plants inoculated with Ga and Gv were decreased by N addition, whereas shoot K, Na, Ca and Mg concentration in plants inoculated with Gt were not negatively affected. It was observed that N addition only increased mycorrhizal colonization, shoot biomass, shoot K, Ca and Mg content of plants inoculated with Gt. Irrespective of N addition, plants with Gt inoculation got the maximum shoot and root P concentration and content, as well as P/Cd concentration molar ratio among all inoculation treatment. Neither AMF nor N fertilizer contributed to the decrease of soil exchangeable Cd and increase of soil pH. These results suggested that N fertilizer only elevated plant performance of alfalfa with Gt inoculation grown in acidic soil, by diluting Cd concentration and alleviating of nutrient deficiency, especially P.

  8. Content and uptake of minerals in the yolk of broiler embryos during incubation and effect of nutrient enrichment.

    PubMed

    Yair, R; Uni, Z

    2011-07-01

    Although embryo and chicken growth and development rely on mineral nutrition, information on mineral levels in the egg compartments during incubation is limited. Accordingly, we examined P, Ca, Fe, Zn, Cu, and Mn levels in the yolk of breeder eggs during incubation and the effect of embryonic mineral (with specific nutrients) enrichment on yolk mineral levels and consumption. First, fertile eggs were examined on day of setting (DOS), embryonic day (E) 11, E13, E15, E17, E19, E20, and day of hatch (DOH) for the mineral content in the yolk (and albumen on DOS) by inductively coupled plasma atomic emission spectroscopy. Results showed that on DOS, the yolk is the major origin for Mn, P, Fe, Ca, Cu, and Zn. Interestingly, P, Fe, Zn, Cu, and Mn were mostly consumed from the yolk until E17, after which their consumption was very low. Consumption of P was constant until E17 and then decreased until E20. Consumption of Fe, Zn, Cu, and Mn was medium to mild until E11, increased between E11 and E17, and minimal between E17 and DOH. Enrichment treatment, where fertile eggs were divided into 2 groups [nonenriched (control) and enriched (with minerals, vitamins, and carbohydrates on E17 using the in ovo feeding method)] showed that the enriched group had higher Fe, Zn, Cu, and Mn levels than the nonenriched group and exhibited higher consumption of Fe, Zn, and Mn between E20 and DOH. Analysis of the shell mineral composition along incubation showed that the shell released low amounts of P, Fe, and Mn in comparison with the yolk mineral content. Therefore, we concluded that the shell is a minor source of these minerals. Studying the mineral resources and consumption of embryos can lead to a better understanding of the mineral limitations of embryos during incubation. Additionally, because minerals are important for the development of the embryo, the higher mineral levels and consumption observed in the enriched group may affect the development of critical organs, such as the

  9. Rapid adaptation of activated sludge bacteria into a glycogen accumulating biofilm enabling anaerobic BOD uptake.

    PubMed

    Hossain, Md Iqbal; Paparini, Andrea; Cord-Ruwisch, Ralf

    2017-03-01

    Glycogen accumulating organisms (GAO) are known to allow anaerobic uptake of biological oxygen demand (BOD) in activated sludge wastewater treatment systems. In this study, we report a rapid transition of suspended activated sludge biomass to a GAO dominated biofilm by selective enrichment using sequences of anaerobic loading followed by aerobic exposure of the biofilm to air. The study showed that within eight weeks, a fully operational, GAO dominated biofilm had developed, enabling complete anaerobic BOD uptake at a rate of 256mg/L/h. The oxygen uptake by the biofilm directly from the atmosphere had been calculated to provide significant energy savings. This study suggests that wastewater treatment plant operators can convert activated sludge systems readily into a "passive aeration" biofilm that avoids costly oxygen transfer to bulk wastewater solution. The described energy efficient BOD removal system provides an opportunity to be coupled with novel nitrogen removal processes such as anammox.

  10. Microbial evaluation of activated sludge and filamentous population at eight Czech nutrient removal activated sludge plants during year 2000.

    PubMed

    Krhutková, O; Ruzicková, I; Wanner, J

    2002-01-01

    The long-term project on the survey of filamentous microorganisms, which started in 1996, was finished in 2000 by the survey of eight Czech activated sludge plants with biological nutrient removal (BNR) systems. At all plants with enhanced biological nutrient removal, specific microbial population (mostly from the point of view of filaments occurrence), operational problems (presence of biological foaming, bulking) and plant operation were observed periodically and longer than 1 year. In our paper the relationship between the composition of activated sludge (especially filaments) consortia and modification of the process with nutrient removal is discussed. At the surveyed plants Type 0092 and Microthrix parvicella were identified as dominant Eikelboom filamentous types.

  11. Nutrient regulation of bacterial production and ectoenzyme activities in the subtropical North Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Donachie, Stuart P.; Christian, James R.; Karl, David M.

    Interactions between Bacteria and dissolved organic matter (DOM) in the open ocean are poorly understood. While it is likely that particular compounds may disproportionately regulate heterotrophic activity, very little is known about the underlying processes. Through 10 cruises between December 1996 and April 1998 we investigated how heterotrophic (non-pigmented) Bacteria cell production, per cell α- and β-glucosidase and leucine aminopeptidase (LAPase) activities, and 14C-glucose uptake in 0.8 μm filtered seawater (fsw) cultures at Station ALOHA (22°45'N, 158°W) responded to organic and inorganic nutrient additions (glucose, single amino acids, NH 4+, NO 3-). Bacterial cell production did not change significantly in fsw with glucose (1 μM) or single exogenous N sources (1 μM N) compared to that in fsw alone. Furthermore, there was no significant difference in heterotrophic bacterial cell production in fsw amended with organic or inorganic N, nor between that in fsw with organic N and glucose, or inorganic N and glucose. Cell production did increase significantly, however, in fsw with exogenous glucose (0.38 μM) plus 1 μM inorganic N (NH 4+) relative to that in fsw only, in fsw with glucose, and in fsw with 1 μM N as amino acids (His, Tyr, Leu). There was no significant difference between heterotrophic bacterial cell production in fsw with glucose, glucose plus amino acids, and that in fsw alone. Cell-specific LAPase activity increased significantly relative to that in unamended fsw when exogenous glucose plus NH 4+ or NO 3- were provided, but amino acids, glucose, NH 4+ or NO 3- alone had little or no effect. α-Glucosidase activity tended to increase with exogenous His and Tyr additions. Our results suggest that heterotrophic activity at Station ALOHA can be regulated by the abundance of particular compounds, regardless of their total concentrations. It appears that auxotrophy and de novo synthesis of cell protein from glucose may coexist among Bacteria

  12. Increased skeletal muscle glucose uptake by rosemary extract through AMPK activation.

    PubMed

    Naimi, Madina; Tsakiridis, Theodoros; Stamatatos, Theocharis C; Alexandropoulos, Dimitris I; Tsiani, Evangelia

    2015-04-01

    Stimulation of the energy sensor AMP-activated kinase (AMPK) has been viewed as a targeted approach to increase glucose uptake by skeletal muscle and control blood glucose homeostasis. Rosemary extract (RE) has been reported to activate AMPK in hepatocytes and reduce blood glucose levels in vivo but its effects on skeletal muscle are not known. In the present study, we examined the effects of RE and the mechanism of regulation of glucose uptake in muscle cells. RE stimulated glucose uptake in L6 myotubes in a dose- and time-dependent manner. Maximum stimulation was seen with 5 μg/mL of RE for 4 h (184% ± 5.07% of control, p < 0.001), a response comparable to maximum insulin (207% ± 5.26%, p < 0.001) and metformin (216% ± 8.77%, p < 0.001) stimulation. RE did not affect insulin receptor substrate 1 and Akt phosphorylation but significantly increased AMPK and acetyl-CoA carboxylase phosphorylation. Furthermore, the RE-stimulated glucose uptake was significantly reduced by the AMPK inhibitor compound C, but remained unchanged by the PI3K inhibitor, wortmannin. RE did not affect GLUT4 or GLUT1 glucose transporter translocation in contrast with a significant translocation of both transporters seen with insulin or metformin treatment. Our study is the first to show a direct effect of RE on muscle cell glucose uptake by a mechanism that involves AMPK activation.

  13. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.)

    PubMed Central

    Agbodjato, Nadège A.; Noumavo, Pacôme A.; Adjanohoun, Adolphe; Agbessi, Léonce; Baba-Moussa, Lamine

    2016-01-01

    This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR) and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84%) and germinated seed weight (31.39%) whereas chitosan-P. putida has increased the shoot weight (65.67%). For the growth test, the maximal heights (17.66%) were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%), aerial (84.66%), and underground biomass (108.77%) production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production. PMID:26904295

  14. Impact of defoliation intensities on plant biomass, nutrient uptake and arbuscular mycorrhizal symbiosis in Lotus tenuis growing in a saline-sodic soil.

    PubMed

    García, I; Mendoza, R

    2012-11-01

    The impact of different defoliation intensities on the ability of Lotus tenuis plants to regrowth, mobilise nutrients and to associate with native AM fungi and Rhizobium in a saline-sodic soil was investigated. After 70 days, plants were subjected to 0, 25, 50, 75 and 100% defoliation and shoot regrowth was assessed at the end of subsequent 35 days. Compared to non-defoliated plants, low or moderate defoliation up to 75% did not affect shoot regrowth. However, 100% treatment affected shoot regrowth and the clipped plants were not able to compensate the growth attained by non-defoliated plants. Root growth was more affected by defoliation than shoot growth. P and N concentrations in shoots and roots increased with increasing defoliation while Na(+) concentration in shoots of non-defoliated and moderately defoliated plants was similar. Non-defoliated and moderately defoliated plants prevented increases of Na(+) concentration in shoots through both reducing Na(+) uptake and Na(+) transport to shoots by accumulating Na(+) in roots. At high defoliation, the salinity tolerance mechanism is altered and Na(+) concentration in shoots was higher than in roots. Reduction in the photosynthetic capacity induced by defoliation neither changed the root length colonised by AM fungi nor arbuscular colonisation but decreased the vesicular colonisation. Spore density did not change, but hyphal density and Rhizobium nodules increased with defoliation. The strategy of the AM symbiont consists in investing most of the C resources to preferentially retain arbuscular colonisation as well as inoculum density in the soil.

  15. Synergistic Effects of Plant Growth Promoting Rhizobacteria and Chitosan on In Vitro Seeds Germination, Greenhouse Growth, and Nutrient Uptake of Maize (Zea mays L.).

    PubMed

    Agbodjato, Nadège A; Noumavo, Pacôme A; Adjanohoun, Adolphe; Agbessi, Léonce; Baba-Moussa, Lamine

    2016-01-01

    This study aimed to assess the effects of three plant growth promoting rhizobacteria (PGPR) and chitosan either singly or in combination on maize seeds germination and growth and nutrient uptake. Maize seeds were treated with chitosan and bacterial solution. The germination and growth tests were carried out in square Petri dishes and plastic pots. The combination chitosan-A. lipoferum-P. fluorescens has increased the seeds vigor index up to 36.44% compared to the control. In comparison to the control, P. putida has significantly improved root weight (44.84%) and germinated seed weight (31.39%) whereas chitosan-P. putida has increased the shoot weight (65.67%). For the growth test, the maximal heights (17.66%) were obtained by plants treated with the combination A. lipoferum-P. fluorescens-P. putida. Chitosan-P. fluorescens induced the highest increases of leaves per plant (50.09%), aerial (84.66%), and underground biomass (108.77%) production. The plants inoculated with A. lipoferum had the large leaf areas with an increase of 54.08%, while combinations P. fluorescens-P. putida and chitosan-A. lipoferum improved the aerial and underground dry matter of plants to 26.35% and 18.18%. The nitrogen content of the plants was increased by chitosan-A. lipoferum-P. fluorescens-P. putida with an increasing of 41.61%. The combination of chitosan and PGPR can be used as biological fertilizers to increase maize production.

  16. Effects of Selected Surfactants on Nutrient Uptake and Soil Microbial Activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants are adjuvants that facilitate and accentuate the emulsifying, dispersing, spreading, wetting, or other surface modifying properties of liquids. Many pesticides require the addition of a surfactant to improve pesticide performance in spray solution. Soils are one of the direct recipients ...

  17. Impact of open-ocean convection on nutrients, phytoplankton biomass and activity

    NASA Astrophysics Data System (ADS)

    Severin, T.; Conan, P.; Durrieu de Madron, X.; Houpert, L.; Oliver, M. J.; Oriol, L.; Caparros, J.; Ghiglione, J. F.; Pujo-Pay, M.

    2014-12-01

    We describe the impact of an open-ocean convection event on nutrient budgets, carbon budget, elemental stoichiometry, phytoplankton biomass and activity in the Northwestern Mediterranean Sea (NWM). In the convective episode examined here we estimated an input of nutrients to the surface layer of 7.0, 8.0 and 0.4×108 mol of silicate, nitrate and phosphate, respectively. These quantities correspond to the annual nutrient input by river discharges and atmospheric depositions in the Gulf of Lion. Such nutrient input is sufficient to sustain new primary production from 46 to 63 g C m-2 y-1, which is the same order of magnitude found in the NWM open waters. Our results together with satellite data analysis, propose new scenarios that explain the origin of the spring phytoplankton bloom occurring in NWM.

  18. Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons

    NASA Astrophysics Data System (ADS)

    Brooks, A. J.; Lim, Hyung-nam; Kilduff, James E.

    2012-07-01

    Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7-8.3). Experiments were performed using a suite of model aromatic compounds having a range of π-electron energy to investigate the role of π-π electron donor-acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects

  19. Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons.

    PubMed

    Brooks, A J; Lim, Hyung-nam; Kilduff, James E

    2012-07-27

    Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7-8.3). Experiments were performed using a suite of model aromatic compounds having a range of π-electron energy to investigate the role of π-π electron donor-acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects

  20. Kinetic effect of Pd additions on the hydrogen uptake of chemically activated, ultramicroporous carbon

    SciTech Connect

    Bhat, Vinay V; Contescu, Cristian I; Gallego, Nidia C

    2010-01-01

    The effect of mixing chemically-activated ultramicroporous carbon (UMC) with Pd nanopowder is investigated. Results show that Pd addition doubles the rate of hydrogen uptake, but does not enhance the hydrogen capacity or improve desorption kinetics. The effect of Pd on the rate of hydrogen adsorption supports the occurrence of the hydrogen spillover mechanism in the Pd - UMC system.

  1. Assessment of glutamine synthetase activity by [13N]ammonia uptake in living rat brain.

    PubMed

    Momosaki, Sotaro; Ito, Miwa; Tonomura, Misato; Abe, Kohji

    2015-01-01

    Glutamine synthetase (GS) plays an important role in glutamate neurotransmission or neurological disorder in the brain. [(13) N]Ammonia blood flow tracer has been reported to be metabolically trapped in the brain via the glutamate-glutamine pathway. The present study investigated the effect of an inhibitor of GS on [(13) N]ammonia uptake in order to clarify the feasibility of measuring GS activity in the living brain. l-Methionine sulfoximine (MSO), a selective GS inhibitor was microinjected into the ipsilateral striatum in rats. [(13) N]Ammonia uptake was quantified by autoradiography method as well as small animal positron emission tomography (PET) scans. The GS activity of the brain homogenate was assayed from the γ-glutamyl transferase reaction. Autoradiograms showed a decrease of [(13) N]ammonia radioactivity on the MSO-injected side compared with the saline-injected side of the striatum. This reduction could be detected with a small animal PET scanner. MSO had no effect on cerebral blood flow measured by uptake of [(15) O]H2 O. The reduction of [(13) N]ammonia uptake was closely related to the results of GS activity assay. These results indicated that [(13) N]ammonia may enable measurement of GS activity in the living brain.

  2. All Physical Activity May Not Be Associated with a Lower Likelihood of Adolescent Smoking Uptake

    PubMed Central

    Audrain-McGovern, Janet; Rodriguez, Daniel

    2015-01-01

    Objective Research has documented that physical activity is associated with a lower risk of adolescent smoking uptake, yet it is unclear whether this relationship exists for all types of physical activity. We sought to determine whether certain types of physical activity are associated with a decreased or an increased risk of adolescent smoking uptake. Methods In this longitudinal cohort study, adolescents (n=1,356) were surveyed every six months for four years (age 14 – 18 years old). Smoking and physical activity were measured at each of the eight time-points. Physical activity that was negatively associated with smoking across the eight waves was considered positive physical activities (i.e., PPA; linked to not smoking such as racquet sports, running, and swimming laps). Physical activity that was positively associated with smoking across the eight waves were considered negative physical activities (i.e., NPA; linked to smoking such as skating, walking, bicycling, sport fighting, and competitive wrestling). Results Associative Processes Latent Growth Curve Modeling revealed that each 30-minute increase in NPA per week at baseline was associated with a 4-fold increased odds of smoking progression (OR=4.10, 95% CI=2.14, 7.83). By contrast, each 30-minute increase in PPA at baseline was associated with a 51% decrease in the odds of smoking progression (OR=.49, 95% CI=.25, .93). Conclusions The type of physical activity that an adolescent engages appears to be important for the uptake of cigarette smoking among adolescents. These associative relationships warrant consideration in interventions to increase overall physical activity and those promoting physical activity to prevent smoking uptake. PMID:26280377

  3. Berberine activates GLUT1-mediated glucose uptake in 3T3-L1 adipocytes.

    PubMed

    Kim, So Hui; Shin, Eun-Jung; Kim, Eun-Do; Bayaraa, Tsenguun; Frost, Susan Cooke; Hyun, Chang-Kee

    2007-11-01

    It has recently been known that berberine, an alkaloid of medicinal plants, has anti-hyperglycemic effects. To explore the mechanism underlying this effect, we used 3T3-L1 adipocytes for analyzing the signaling pathways that contribute to glucose transport. Treatment of berberine to 3T3-L1 adipocytes for 6 h enhanced basal glucose uptake both in normal and in insulin-resistant state, but the insulin-stimulated glucose uptake was not augmented significantly. Inhibition of phosphatidylinositol 3-kinase (PI 3-K) by wortmannin did not affect the berberine effect on basal glucose uptake. Berberine did not augment tyrosine phosphorylation of insulin receptor (IR) and insulin receptor substrate (IRS)-1. Further, berberine had no effect on the activity of the insulin-sensitive downstream kinase, atypical protein kinase C (PKCzeta/lambda). However, interestingly, extracellular signal-regulated kinases (ERKs), which have been known to be responsible for the expression of glucose transporter (GLUT)1, were significantly activated in berberine-treated 3T3-L1 cells. As expected, the level of GLUT1 protein was increased both in normal and insulin-resistant cells in response to berberine. But berberine affected the expression of GLUT4 neither in normal nor in insulin-resistant cells. In addition, berberine treatment increased AMP-activated protein kinase (AMPK) activity in 3T3-L1 cells, which has been reported to be associated with GLUT1-mediated glucose uptake. Together, we concluded that berberine increases glucose transport activity of 3T3-L1 adipocytes by enhancing GLUT1 expression and also stimulates the GLUT1-mediated glucose uptake by activating GLUT1, a result of AMPK stimulation.

  4. The effect of nitrite on aerobic phosphate uptake and denitrifying activity of phosphate-accumulating organisms.

    PubMed

    Yoshida, Y; Takahashi, K; Saito, T; Tanaka, K

    2006-01-01

    An anaerobic/aerobic/anoxic/aerobic sequencing batch reactor (SBR) was operated with municipal wastewater to investigate the effect of nitrite on biological phosphorus removal (BPR). When nitrite accumulated, aerobic phosphate uptake activity significantly decreased and, in case of hard exposure to nitrite, BPR severely deteriorated. The interesting observation was that the relative anoxic activity of phosphate accumulating organisms (PAOs) increased after nitrite exposure. Moreover batch tests of aerobic phosphate uptake in the presence/absence of nitrite indicated that PAOs with the higher relative anoxic activity are less sensitive to nitrite exposure. From these results, we concluded that BPR is sensitive to nitrite exposure, but BPR containing PAOs with the higher relative anoxic activity is possibly more stable against nitrite than BPR containing PAOs with the lower relative anoxic activity.

  5. Nutrient uptake by marine invertebrates: cloning and functional analysis of amino acid transporter genes in developing sea urchins (Strongylocentrotus purpuratus).

    PubMed

    Meyer, Eli; Manahan, Donal T

    2009-08-01

    Transport of amino acids from low concentrations in seawater by marine invertebrates has been extensively studied, but few of the genes involved in this physiological process have been identified. We have characterized three amino acid transporter genes cloned from embryos of the sea urchin Strongylocentrotus purpuratus. These genes show phylogenetic proximity to classical amino acid transport systems, including Gly and B0+, and the inebriated gene (INE). Heterologous expression of these genes in frog oocytes induced a 40-fold increase in alanine transport above endogenous levels, demonstrating that these genes mediate alanine transport. Antibodies specific to one of these genes (Sp-AT1) inhibited alanine transport, confirming the physiological activity of this gene in larvae. Whole-mount antibody staining of larvae revealed expression of Sp-AT1 in the ectodermal tissues associated with amino acid transport, as independently demonstrated by autoradiographic localization of radioactive alanine. Maximum rates of alanine transport increased 6-fold during early development, from embryonic to larval stages. Analysis of gene expression during this developmental period revealed that Sp-AT1 transcript abundance remained nearly constant, while that of another transporter gene (Sp-AT2) increased 11-fold. The functional characterization of these genes establishes a molecular biological basis for amino acid transport by developmental stages of marine invertebrates.

  6. Glabridin induces glucose uptake via the AMP-activated protein kinase pathway in muscle cells.

    PubMed

    Sawada, Keisuke; Yamashita, Yoko; Zhang, Tianshun; Nakagawa, Kaku; Ashida, Hitoshi

    2014-08-05

    The present study demonstrates that glabridin, a prenylated isoflavone in licorice, stimulates glucose uptake through the adenosine monophosphate-activated protein kinase (AMPK) pathway in L6 myotubes. Treatment with glabridin for 4h induced glucose uptake in a dose-dependent manner accompanied by the translocation of glucose transporter type 4 (GLUT4) to the plasma membrane. Glabridin needed at least 4h to increase glucose uptake, while it significantly decreased glycogen and increased lactic acid within 15 min. Pharmacological inhibition of AMPK by Compound C suppressed the glabridin-induced glucose uptake, whereas phosphoinositide 3-kinase and Akt inhibition by LY294002 and Akt1/2 inhibitor, respectively, did not. Furthermore, glabridin induced AMPK phosphorylation, and siRNA for AMPK completely abolished glabridin-induced glucose uptake. We confirmed that glabridin-rich licorice extract prevent glucose intolerance accompanied by the AMPK-dependent GLUT4 translocation in the plasma membrane of mice skeletal muscle. These results indicate that glabridin may possess a therapeutic effect on metabolic disorders, such as diabetes and hyperglycemia, by modulating glucose metabolism through AMPK in skeletal muscle cells.

  7. Relationship between uptake of mercury vapor by mushrooms and its catalase activity

    SciTech Connect

    Ogata, M.; Kenmotsu, K.; Hirota, N.; Naito, M.

    1981-12-01

    The uptake of mercury vapor by mushrooms (Shiitake) artifically grown on an oak tree and the uptake in vitro by catalase extracts prepared from mushroom Hay Bacillus and spinach are reported. Mushrooms were exposed to 1.4 mg/Hg/cu m for 11 days. Measurement of total mercury was as previously described (Ogata et al. 1978, 1979). Levels in mushrooms ranged from 0.4 +/- 0.1 ..mu..g/g at 0.5 days to 4.6 +/- 0.2 ..mu..g/g at 10.5 days and steady-state thereafter. In in vitro studies Hy uptake by mushroom catalase extract was estimated by the perborate method. Uptake was found to parallel catalase activity and was inhibited by potassium cyanide, sodium azide, and 3-amino-1,2,4-triazole. Similar results were obtained with Hay Bacillus and spinach catalase extracts. Results suggest that the level of mercury in the mushroom can be used as an indicator of mercury pollution in the environment. It is also suggested that catalase has an important role in uptake of mercury vapor in the plant. 2 tables (JMT)

  8. Calcium uptake in rat liver mitochondria accompanied by activation of ATP-dependent potassium channel.

    PubMed

    Akopova, O V; Nosar, V I; Mankovskaya, I N; Sagach, V F

    2008-10-01

    The influence of potassium ions on calcium uptake in rat liver mitochondria is studied. It is shown that an increase in K+ and Ca2+ concentrations in the incubation medium leads to a decrease in calcium uptake in mitochondria together with a simultaneous increase in potassium uptake due to the potential-dependent transport of K+ in the mitochondrial matrix. Both effects are more pronounced in the presence of an ATP-dependent K+-channel (K+(ATP)-channel) opener, diazoxide (Dz). Activation of the K+(ATP)-channel by Dz alters the functional state of mitochondria and leads to an increase in the respiration rate in state 2 and a decrease in the oxygen uptake and the rate of ATP synthesis in state 3. The effect of Dz on oxygen consumption in state 3 is mimicked by valinomycin, but it is opposite to that of the classical protonophore uncoupler CCCP. It is concluded that the potential-dependent uptake of potassium is closely coupled to calcium transport and is an important parameter of energy coupling responsible for complex changes in oxygen consumption and Ca2+-transport properties of mitochondria.

  9. Modelling orange tree root water uptake active area by minimally invasive ERT data and transpiration measurements

    NASA Astrophysics Data System (ADS)

    Vanella, Daniela; Boaga, Jacopo; Perri, Maria Teresa; Consoli, Simona; Cassiani, Giorgio

    2015-04-01

    The comprehension of the hydrological processes involving plant root dynamics is crucial for implementing water saving measures in agriculture. This is particular urgent in areas, like those Mediterranean, characterized by scarce water availability. The study of root water dynamics should not be separated from a more general analysis of the mass and energy fluxes transferred in the soil-plant-atmosphere continuum. In our study, in order to carry this inclusive approach, minimal invasive 3D time-lapse electrical resistivity tomography (ERT) for soil moisture estimation was combined with plant transpiration fluxes directly measured with Sap Flow (SF) techniques and Eddy Covariance methods, and volumetric soil moisture measurements by TDR probes. The main objective of this inclusive approach was to accurately define root-zone water dynamics and individuate the root-area effectively active for water and nutrient uptake process. The monitoring was carried out in Eastern Sicily (south Italy) in summers 2013 and 2014, within an experimental orange orchard farm. During the first year of experiment (October 2013), ERT measurements were carried out around the pertinent volume of one fully irrigated tree, characterized by a vegetation ground cover of 70%; in the second year (June 2014), ERT monitoring was conducted considering a cutting plant, thus to evaluate soil water dynamics without the significant plant transpiration contribution. In order to explore the hydrological dynamics of the root zone volume surrounded by the monitored tree, the resistivity data acquired during the ERT monitoring were converted into soil moisture content distribution by a laboratory calibration based on the soil electrical properties as a function of moisture content and pore water electrical conductivity. By using ERT data in conjunction with the agro-meteorological information (i.e. irrigation rates, rainfall, evapotranspiration by Eddy Covariance, transpiration by Sap Flow and soil moisture

  10. Aquatic plant nutrients, moss phosphatase activities and tissue composition in four upland streams in northern England

    NASA Astrophysics Data System (ADS)

    Ellwood, N. T. W.; Haile, S. M.; Whitton, B. A.

    2008-02-01

    SummaryA study was made of the water chemistry, tissue nutrients and surface phosphatase activities of the 2-cm apices of three mosses in four upland streams in northern England, UK. This was part of a project to optimize methods for assessing nutrient fractions in environments with highly variable water chemistry. Aqueous N and P fractions showed the greatest variability followed by moss phosphatase activities, with nutrient composition of the shoot apices the least variable. There was no consistent pattern as to which aqueous N or P fraction was the most variable. The ratio between total inorganic N and total filtrable P ranged over three orders of magnitude in some streams. The interrelations between tissue N and P concentrations, tissue N:P ratio, phosphatase activities and aqueous variables showed: Significant +ve relationship between tissue N and aqueous NO 3-N in some populations, but not between tissue P and aqueous P concentration; Significant +ve relationships between phosphatase activities and aqueous organic N, but none with aqueous organic P; Significant +ve relationships between phosphodiesterase:phosphomonoesterase activities and aqueous organic N; Significant -ve relationships between phosphatase activities and tissue P concentration; Significant +ve relationships between phosphatase activities and tissue N:P. Both types of biological measurement are valuable for monitoring ambient nutrients in upland streams. Neither is clearly better than the other, so both should be included in surveys.

  11. [Effects of two controlled-release fertilizers with different proportions of N, P and K on the nutrient uptake and growth of Chrysanthemum morifolium Ramat].

    PubMed

    Zhu, Li-Xiang; Wang, Jian-Hua; Sun, Yin-Shi; Li, Yu-Peng; Sun, Li-Wen; Zhang, Chun-Ling

    2009-07-01

    A pot experiment was conducted to study the effects of two controlled-release fertilizers CRFA (4% resin-coated, N: P2O5: K2O = 14: 14: 14) and CRFB (4% resin-coated, N: P2O5: K2O = 20: 8:10) on the nutrient uptake and growth of Chrysanthemum morifolium, with common compound fertilizer CCF (N: P2O5: K2O = 15: 15: 15) as the control. Six treatments were installed, i. e., CCF1 (CCF, 6 g N x pot(-1)), CCF2 (CCF, 3 g N x pot(-1)), CRFA1 (CRFA, 6 g x pot(-1)), CRFA2 (CRFA, 3 g x pot(-1)), CRFB1 (CRFB, 6 g x pot(-1)), and CRFB (CRFB, 3 g x pot(-1)). On the 30th day of applying common compound fertilizer CCF1 and CCF2, soil available N, P and K contents were 163.29 and 145.26 mg x kg(-1), 180.39 and 163.13 mg x kg(-1), and 300.08 and 213.15 mg x kg(-1), respectively, and decreased rapidly since then. In treatments CRFA1, CRFB1, CRFA2, and CRFB, soil available N content increased slowly, and reached the peak on the 60th day after fertilizing, being 129.51, 138.65, 118.36, and 126.31 mg x kg(-1), respectively. Soil available P content had the same variation trend. Its maximum concentration was 169.54 and 133.46 mg x kg(-1) in treatments CRFA1 and CRFA2 on the 30th day after fertilizing, and 137.13 and 84.68 mg x kg(-1) in treatments CRFB1 and CRFB2 on the 60th day after fertilizing, and decreased slowly then. The agronomic traits such as leaf area, leaf area index, branch number, flowering rate, flower number, and flower diameter, etc., in treatments CRFA and CRFB were obviously better than those of the control, and CRFB was better than CRFA, suggesting that CRFB more matched the nutrient demand of C. morifolium. Under the conditions of present experiment, applying CRFB2 obtained the highest yield.

  12. Coupling between Nutrient Availability and Thyroid Hormone Activation*

    PubMed Central

    Lartey, Lattoya J.; Werneck-de-Castro, João Pedro; O-Sullivan, InSug; Unterman, Terry G.; Bianco, Antonio C.

    2015-01-01

    The activity of the thyroid gland is stimulated by food availability via leptin-induced thyrotropin-releasing hormone/thyroid-stimulating hormone expression. Here we show that food availability also stimulates thyroid hormone activation by accelerating the conversion of thyroxine to triiodothyronine via type 2 deiodinase in mouse skeletal muscle and in a cell model transitioning from 0.1 to 10% FBS. The underlying mechanism is transcriptional derepression of DIO2 through the mTORC2 pathway as defined in rictor knockdown cells. In cells kept in 0.1% FBS, there is DIO2 inhibition via FOXO1 binding to the DIO2 promoter. Repression of DIO2 by FOXO1 was confirmed using its specific inhibitor AS1842856 or adenoviral infection of constitutively active FOXO1. ChIP studies indicate that 4 h after 10% FBS-containing medium, FOXO1 binding markedly decreases, and the DIO2 promoter is activated. Studies in the insulin receptor FOXO1 KO mouse indicate that insulin is a key signaling molecule in this process. We conclude that FOXO1 represses DIO2 during fasting and that derepression occurs via nutritional activation of the PI3K-mTORC2-Akt pathway. PMID:26499800

  13. Salts and nutrients present in regenerated waters induce changes in water relations, antioxidative metabolism, ion accumulation and restricted ion uptake in Myrtus communis L. plants.

    PubMed

    Acosta-Motos, José R; Alvarez, Sara; Barba-Espín, Gregorio; Hernández, José A; Sánchez-Blanco, María J

    2014-12-01

    The use of reclaimed water (RW) constitutes a valuable strategy for the efficient management of water and nutrients in landscaping. However, RW may contain levels of toxic ions, affecting plant production or quality, a very important aspect for ornamental plants. The present paper evaluates the effect of different quality RWs on physiological and biochemical parameters and the recovery capacity in Myrtus communis L. plants. M. communis plants were submitted to 3 irrigation treatments with RW from different sources (22 weeks): RW1 (1.7 dS m(-1)), RW2 (4.0 dS m(-1)) and RW3 (8.0 dS m(-1)) and one control (C, 0.8 dS m(-1)). During a recovery period of 11 weeks, all plants were irrigated with the control water. The RW treatments did not negatively affect plant growth, while RW2 even led to an increase in biomass. After recovery,only plants irrigated with RW3 showed some negative effects on growth, which was related to a decrease in the net photosynthesis rate, higher Na accumulation and a reduction in K levels. An increase in salinity was accompanied by decreases in leaf water potential, relative water content and gas exchange parameters, and increases in Na and Cl uptake. Plants accumulated Na in roots and restricted its translocation to the aerial part. The highest salinity levels produced oxidative stress, as seen from the rise in electrolyte leakage and lipid peroxidation. The use of regenerated water together with carefully managed drainage practices, which avoid the accumulation of salt by the substrate, will provide economic and environmental benefits.

  14. Tetrodotoxin-insensitive Na+ channel activator palytoxin inhibits tyrosine uptake into cultured bovine adrenal chromaffin cells

    SciTech Connect

    Morita, K.; Teraoka, K.; Azuma, M.; Oka, M.; Hamano, S. )

    1991-07-01

    The effects of the tetrodotoxin-insensitive Na+ channel activator palytoxin on both the secretion of endogenous catecholamines and the formation of 14C-catecholamines from (14C)tyrosine were examined using cultured bovine adrenal chromaffin cells. Palytoxin was shown to cause the stimulation of catecholamine secretion in a concentration-dependent manner. However, this toxin caused the reduction rather than the stimulation of 14C-catecholamine formation at the same concentrations. Palytoxin failed to cause any alteration in the activity of tyrosine hydroxylase prepared from bovine adrenal medulla. Furthermore, the uptake of (14C)tyrosine into the cells was shown to be inhibited by this toxin under the conditions in which the suppression of 14C-catecholamine formation was observed, and this inhibitory action on tyrosine uptake was closely correlated with that on catecholamine formation. The inhibitory action of palytoxin on tyrosine uptake into the cells was observed to be noncompetitive, and this effect was not altered by the removal of Na+ from the incubation mixture. These results suggest that palytoxin may be able to inhibit the uptake of (14C)tyrosine into the cells, resulting in the suppression of 14C-catecholamine formation, probably through its direct action on the plasma membranes of bovine adrenal chromaffin cells.

  15. ReishiMax, mushroom based dietary supplement, inhibits adipocyte differentiation, stimulates glucose uptake and activates AMPK

    PubMed Central

    2011-01-01

    Background Obesity is a health hazard which is closely associated with various complications including insulin resistance, hypertension, dyslipidemia, atherosclerosis, type 2 diabetes and cancer. In spite of numerous preclinical and clinical interventions, the prevalence of obesity and its related disorders are on the rise demanding an urgent need for exploring novel therapeutic agents that can regulate adipogenesis. In the present study, we evaluated whether a dietary supplement ReishiMax (RM), containing triterpenes and polysaccharides extracted from medicinal mushroom Ganoderma lucidum, affects adipocyte differentiation and glucose uptake in 3T3-L1 cells. Methods 3T3-L1 pre-adipocytes were differentiated into adipocytes and treated with RM (0-300 μg/ml). Adipocyte differentiation/lipid uptake was evaluated by oil red O staining and triglyceride and glycerol concentrations were determined. Gene expression was evaluated by semi-quantitative RT-PCR and Western blot analysis. Glucose uptake was determined with [3H]-glucose. Results RM inhibited adipocyte differentiation through the suppresion of expression of adipogenic transcription factors peroxisome proliferator-activated receptor-γ (PPAR-γ), sterol regulatory element binding element protein-1c (SREBP-1c) and CCAAT/enhancer binding protein-α (C/EBP-α). RM also suppressed expression of enzymes and proteins responsible for lipid synthesis, transport and storage: fatty acid synthase (FAS), acyl-CoA synthetase-1 (ACS1), fatty acid binding protein-4 (FABP4), fatty acid transport protein-1 (FATP1) and perilipin. RM induced AMP-activated protein kinase (AMPK) and increased glucose uptake by adipocytes. Conclusion Our study suggests that RM can control adipocyte differentiation and glucose uptake. The health benefits of ReishiMax warrant further clinical studies. PMID:21929808

  16. H2O2 pretreated rice seedlings specifically reduces arsenate not arsenite: difference in nutrient uptake and antioxidant defense response in a contrasting pair of rice cultivars.

    PubMed

    Mallick, Shekhar; Kumar, Navin; Sinha, Sarita; Dubey, Arvind Kumar; Tripathi, Rudra Deo; Srivastav, Vivek

    2014-10-01

    The study investigated the reduction in metalloid uptake at equimolar concentrations (~53.3 μM) of As(III) and As(V) in contrasting pair of rice seedlings by pretreating with H2O2 (1.0 μM) and SA (1.0 mM). Results obtained from the contrasting pair (arsenic tolerant vs. sensitive) of rice seedlings (cv. Pant Dhan 11 and MTU 7029, respectively) shows that pretreatment of H2O2 and H2O2 + SA reduces As(V) uptake significantly in both the cultivars, while no reduction in the As(III) uptake. The higher growth inhibition, higher H2O2 and TBARS content in sensitive cultivar against As(III) and As(V) treatments along with higher As accumulation (~1.2 mg g(-1) dw) than in cv. P11, unravels the fundamental difference in the response between the sensitive and tolerant cultivar. In the H2O2 pretreated plants, the translocation of As increased in tolerant cultivar against AsIII, whereas, it decreased in sensitive cultivar both against AsIII and AsV. In both the cultivars translocation of Mn increased in the H2O2 pretreated plants against As(III), whereas, the translocation of Cu increased against As(V). In tolerant cultivar the translocation of Fe increased against As(V) with H2O2 pretreatment whereas, it decreased in the sensitive cultivar. In both the cultivars, Zn translocation increased against As(III) and decreased against As(V). The higher level of H2O2 and SOD (EC 1.15.1.1) activity in sensitive cultivar whereas, higher, APX (EC 1.11.1.11), GR (EC 1.6.4.2) and GST (EC 1.6.4.2) activity in tolerant cultivar, also demonstrated the differential anti-oxidative defence responses between the contrasting rice cultivars.

  17. Effects of nutrient enrichment on the decomposition of wood and associated microbial activity in streams

    USGS Publications Warehouse

    Gulis, V.; Rosemond, A.D.; Suberkropp, K.; Weyers, H.S.; Benstead, J.P.

    2004-01-01

    1. We determined the effects of nutrient enrichment on wood decomposition rates and microbial activity during a 3-year study in two headwater streams at Coweeta Hydrologic Laboratory, NC, U.S.A. After a 1-year pretreatment period, one of the streams was continuously enriched with inorganic nutrients (nitrogen and phosphorus) for 2 years while the other stream served as a reference. We determined the effects of enrichment on both wood veneers and sticks, which have similar carbon quality but differ in physical characteristics (e.g. surface area to volume ratios, presence of bark) that potentially affect microbial colonisation and activity. 2. Oak wood veneers (0.5 mm thick) were placed in streams monthly and allowed to decompose for approximately 90 days. Nutrient addition stimulated ash-free dry mass loss and increased mean nitrogen content, fungal biomass and microbial respiration on veneers in the treatment stream compared with the reference. The magnitude of the response to enrichment was great, with mass loss 6.1 times, and per cent N, fungal biomass and microbial respiration approximately four times greater in the treatment versus reference stream. 3. Decomposition rate and nitrogen content of maple sticks (ca. 1-2 cm diameter) also increased; however, the effect was less pronounced than for veneers. Wood response overall was greater than that determined for leaves in a comparable study, supporting the hypothesis that response to enrichment may be greater for lower quality organic matter (high C:N) than for higher quality (low C:N) substrates. 4. Our results show that moderate nutrient enrichment can profoundly affect decomposition rate and microbial activity on wood in streams. Thus, the timing and availability of wood that provides retention, structure, attachment sites and food in stream ecosystems may be affected by nutrient concentrations raised by human activities.

  18. Regulation and activity of a zinc uptake regulator, Zur, in Corynebacterium diphtheriae.

    PubMed

    Smith, Kelsy F; Bibb, Lori A; Schmitt, Michael P; Oram, Diana M

    2009-03-01

    Regulation of metal ion homeostasis is essential to bacterial cell survival, and in most species it is controlled by metal-dependent transcriptional regulators. In this study, we describe a Corynebacterium diphtheriae ferric uptake regulator-family protein, Zur, that controls expression of genes involved in zinc uptake. By measuring promoter activities and mRNA levels, we demonstrate that Zur represses transcription of three genes (zrg, cmrA, and troA) in zinc-replete conditions. All three of these genes have similarity to genes involved in zinc uptake. Transcription of zrg and cmrA was also shown to be regulated in response to iron and manganese, respectively, by mechanisms that are independent of Zur. We demonstrate that the activity of the zur promoter is slightly decreased under low zinc conditions in a process that is dependent on Zur itself. This regulation of zur transcription is distinctive and has not yet been described for any other zur. An adjacent gene, predicted to encode a metal-dependent transcriptional regulator in the ArsR/SmtB family, is transcribed from a separate promoter whose activity is unaffected by Zur. A C. diphtheriae zur mutant was more sensitive to peroxide stress, which suggests that zur has a role in protecting the bacterium from oxidative damage. Our studies provide the first evidence of a zinc specific transcriptional regulator in C. diphtheriae and give new insights into the intricate regulatory network responsible for regulating metal ion concentrations in this toxigenic human pathogen.

  19. Biological uptake of polychlorinated biphenyls by Macoma balthica from sediment amended with activated carbon

    USGS Publications Warehouse

    McLeod, Pamela B.; van den Heuvel-Greve, Martine J.; Luoma, S.N.; Luthy, R.G.

    2007-01-01

    This work characterizes the efficacy of activated carbon amendment in reducing polychlorinated biphenyl (PCB) bioavailability to clams (Macoma balthica) from field-contaminated sediment (Hunters Point Naval Shipyard, San Francisco Bay, CA, USA) Test methods were developed for the use of clams to investigate the effects of sediment amendment on biological uptake. Sediment was mixed with activated carbon for one month. Bioaccumulation tests (28 d) were employed to assess the relationships between carbon dose and carbon particle size on observed reductions in clam biological uptake of PCBs. Extraction and cleanup protocols were developed for the clam tissue. Efficacy of activated carbon treatment was found to increase with both increasing carbon dose and decreasing carbon particle size. Average reductions in bioaccumulation of 22, 64, and 84% relative to untreated Hunters Point sediment were observed for carbon amendments of 0.34, 1.7, and 3.4%, respectively. Average bioaccumulation reductions of 41, 73, and 89% were observed for amendments (dose = 1.7% dry wt) with carbon particles of 180 to 250, 75 to 180, and 25 to 75 ??m, respectively, in diameter, indicating kinetic phenomena in these tests. Additionally, a biodynamic model quantifying clam PCB uptake from water and sediment as well as loss through elimination provided a good fit of experimental data. Model predictions suggest that the sediment ingestion route contributed 80 to 95% of the PCB burdens in the clams. ?? 2007 SETAC.

  20. External carbonic anhydrase in three Caribbean corals: quantification of activity and role in CO2 uptake

    NASA Astrophysics Data System (ADS)

    Tansik, Anna L.; Fitt, William K.; Hopkinson, Brian M.

    2015-09-01

    Scleractinian corals have complicated inorganic carbon ( C i) transport pathways to support both photosynthesis, by their symbiotic dinoflagellates, and calcification. The first step in C i acquisition, uptake into the coral, is critical as the diffusive boundary layer limits the supply of CO2 to the surface and HCO3 - uptake is energy intensive. An external carbonic anhydrase (eCA) on the oral surface of corals is thought to facilitate CO2 uptake by converting HCO3 - into CO2, helping to overcome the limitation imposed by the boundary layer. However, this enzyme has not yet been identified or detected in corals, nor has its activity been quantified. We have developed a method to quantify eCA activity using a reaction-diffusion model to analyze data on 18O removal from labeled C i. Applying this technique to three species of Caribbean corals ( Orbicella faveolata, Porites astreoides, and Siderastrea radians) showed that all species have eCA and that the potential rates of CO2 generation by eCA greatly exceed photosynthetic rates. This demonstrates that eCA activity is sufficient to support its hypothesized role in CO2 supply. Inhibition of eCA severely reduces net photosynthesis in all species (on average by 46 ± 27 %), implying that CO2 generated by eCA is a major carbon source for photosynthesis. Because of the high permeability of membranes to CO2, CO2 uptake is likely driven by a concentration gradient across the cytoplasmic membrane. The ubiquity of eCA in corals from diverse genera and environments suggests that it is fundamental for photosynthetic CO2 supply.

  1. Elevated CO2 plus chronic warming reduce nitrogen uptake and levels or activities of nitrogen-uptake and -assimilatory proteins in tomato roots.

    PubMed

    Jayawardena, Dileepa M; Heckathorn, Scott A; Bista, Deepesh R; Mishra, Sasmita; Boldt, Jennifer K; Krause, Charles R

    2017-03-01

    Atmospheric CO2 enrichment is expected to often benefit plant growth, despite causing global warming and nitrogen (N) dilution in plants. Most plants primarily procure N as inorganic nitrate (NO3(-) ) or ammonium (NH4(+) ), using membrane-localized transport proteins in roots, which are key targets for improving N use. Although interactive effects of elevated CO2 , chronic warming and N form on N relations are expected, these have not been studied. In this study, tomato (Solanum lycopersicum) plants were grown at two levels of CO2 (400 or 700 ppm) and two temperature regimes (30 or 37°C), with NO3(-) or NH4(+) as the N source. Elevated CO2 plus chronic warming severely inhibited plant growth, regardless of N form, while individually they had smaller effects on growth. Although %N in roots was similar among all treatments, elevated CO2 plus warming decreased (1) N-uptake rate by roots, (2) total protein concentration in roots, indicating an inhibition of N assimilation and (3) shoot %N, indicating a potential inhibition of N translocation from roots to shoots. Under elevated CO2 plus warming, reduced NO3(-) -uptake rate per g root was correlated with a decrease in the concentration of NO3(-) -uptake proteins per g root, reduced NH4(+) uptake was correlated with decreased activity of NH4(+) -uptake proteins and reduced N assimilation was correlated with decreased concentration of N-assimilatory proteins. These results indicate that elevated CO2 and chronic warming can act synergistically to decrease plant N uptake and assimilation; hence, future global warming may decrease both plant growth and food quality (%N).

  2. 3-Bromopyruvate inhibits calcium uptake by sarcoplasmic reticulum vesicles but not SERCA ATP hydrolysis activity.

    PubMed

    Jardim-Messeder, Douglas; Camacho-Pereira, Juliana; Galina, Antonio

    2012-05-01

    3-Bromopyruvate (3BrPA) is an antitumor agent that alkylates the thiol groups of enzymes and has been proposed as a treatment for neoplasias because of its specific reactivity with metabolic energy transducing enzymes in tumor cells. In this study, we show that the sarco/endoplasmic reticulum calcium (Ca(2+)) ATPase (SERCA) type 1 is one of the target enzymes of 3BrPA activity. Sarco/endoplasmic reticulum vesicles (SRV) were incubated in the presence of 1mM 3BrPA, which was unable to inhibit the ATPase activity of SERCA. However, Ca(2+)-uptake activity was significantly inhibited by 80% with 150 μM 3BrPA. These results indicate that 3BrPA has the ability to uncouple the ATP hydrolysis from the calcium transport activities. In addition, we observed that the inclusion of 2mM reduced glutathione (GSH) in the reaction medium with different 3BrPA concentrations promoted an increase in 40% in ATPase activity and protects the inhibition promoted by 3BrPA in calcium uptake activity. This derivatization is accompanied by a decrease of reduced cysteine (Cys), suggesting that GSH and 3BrPA increases SERCA activity and transport by pyruvylation and/or S-glutathiolation mediated by GSH at a critical Cys residues of the SERCA.

  3. Increased peroxisome proliferator-activated receptor-gamma activity reduces imatinib uptake and efficacy in chronic myeloid leukemia mononuclear cells.

    PubMed

    Wang, Jueqiong; Lu, Liu; Kok, Chung H; Saunders, Verity A; Goyne, Jarrad M; Dang, Phuong; Leclercq, Tamara M; Hughes, Timothy P; White, Deborah L

    2017-02-02

    Imatinib is actively transported by OCT-1 influx transporter, and low OCT-1 activity in diagnostic chronic myeloid leukemia blood mononuclear cells is significantly associated with poor molecular response to imatinib. Here we report that, in diagnostic chronic myeloid leukemia mononuclear cells and BCR-ABL1+ cell lines, peroxisome proliferator-activated receptor gamma agonists (GW1929, rosiglitazone, pioglitazone) significantly decrease OCT-1 activity; conversely, peroxisome proliferator-activated receptor gamma antagonists (GW9662, T0070907) increase OCT-1 activity. Importantly, these effects can lead to corresponding changes in sensitivity to Bcr-Abl kinase inhibition. Results were confirmed in peroxisome proliferator-activated receptor gamma-transduced K562 cells. Furthermore, we identified a strong negative correlation between OCT-1 activity and peroxisome proliferator-activated receptor gamma transcriptional activity in diagnostic chronic myeloid leukemia patients (n=84; p<0.0001), suggesting that peroxisome proliferator-activated receptor gamma activation has a negative impact on the intracellular uptake of imatinib and consequent Bcr-Abl kinase inhibition. The inter-patient variability of peroxisome proliferator-activated receptor gamma activation likely accounts for the heterogeneity observed in patient OCT-1 activity at diagnosis. Recently, the peroxisome proliferator-activated receptor gamma agonist pioglitazone was reported to act synergistically with imatinib targeting the residual chronic myeloid leukemia stem cell pool. Our findings suggest that peroxisome proliferator-activated receptor gamma ligands have differential effects on circulating mononuclear cells compared to stem cells. Since the effect of peroxisome proliferator-activated receptor gamma activation on imatinib uptake in mononuclear cells may counteract the clinical benefit of this activation in stem cells, caution should be applied when combining these therapies, especially in patients

  4. Modeling external carbon addition in biological nutrient removal processes with an extension of the international water association activated sludge model.

    PubMed

    Swinarski, M; Makinia, J; Stensel, H D; Czerwionka, K; Drewnowski, J

    2012-08-01

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to account for a newly defined readily biodegradable substrate that can be consumed by polyphosphate-accumulating organisms (PAOs) under anoxic and aerobic conditions, but not under anaerobic conditions. The model change was to add a new substrate component and process terms for its use by PAOs and other heterotrophic bacteria under anoxic and aerobic conditions. The Gdansk (Poland) wastewater treatment plant (WWTP), which has a modified University of Cape Town (MUCT) process for nutrient removal, provided field data and mixed liquor for batch tests for model evaluation. The original ASM2d was first calibrated under dynamic conditions with the results of batch tests with settled wastewater and mixed liquor, in which nitrate-uptake rates, phosphorus-release rates, and anoxic phosphorus uptake rates were followed. Model validation was conducted with data from a 96-hour measurement campaign in the full-scale WWTP. The results of similar batch tests with ethanol and fusel oil as the external carbon sources were used to adjust kinetic and stoichiometric coefficients in the expanded ASM2d. Both models were compared based on their predictions of the effect of adding supplemental carbon to the anoxic zone of an MUCT process. In comparison with the ASM2d, the new model better predicted the anoxic behaviors of carbonaceous oxygen demand, nitrate-nitrogen (NO3-N), and phosphorous (PO4-P) in batch experiments with ethanol and fusel oil. However, when simulating ethanol addition to the anoxic zone of a full-scale biological nutrient removal facility, both models predicted similar effluent NO3-N concentrations (6.6 to 6.9 g N/m3). For the particular application, effective enhanced biological phosphorus removal was predicted by both models with external carbon addition but, for the new model, the effluent PO4-P concentration was approximately one-half of that found from

  5. WRKY6 Transcription Factor Restricts Arsenate Uptake and Transposon Activation in Arabidopsis[W

    PubMed Central

    Castrillo, Gabriel; Sánchez-Bermejo, Eduardo; de Lorenzo, Laura; Crevillén, Pedro; Fraile-Escanciano, Ana; TC, Mohan; Mouriz, Alfonso; Catarecha, Pablo; Sobrino-Plata, Juan; Olsson, Sanna; Leo del Puerto, Yolanda; Mateos, Isabel; Rojo, Enrique; Hernández, Luis E.; Jarillo, Jose A.; Piñeiro, Manuel; Paz-Ares, Javier; Leyva, Antonio

    2013-01-01

    Stress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during the early evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders it easily incorporated into cells via the phosphate transporters. Here, we found that arsenate stress provokes a notable transposon burst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. This repression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate was removed, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6 as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restricts arsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulates arsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon gene silencing. PMID:23922208

  6. Uptake, delivery, and anticancer activity of thymoquinone nanoparticles in breast cancer cells

    NASA Astrophysics Data System (ADS)

    Fakhoury, Isabelle; Saad, Walid; Bouhadir, Kamal; Nygren, Peter; Schneider-Stock, Regine; Gali-Muhtasib, Hala

    2016-07-01

    Thymoquinone (TQ) is a promising anticancer molecule but its development is hindered by its limited bioavailability. Drug encapsulation is commonly used to overcome low drug solubility, limited bioavailability, and nonspecific targeting. In this project, TQ nanoparticles (TQ-NP) were synthesized and characterized. The cytotoxicity of the NP was investigated in nontumorigenic MCF-10-A breast cells, while the uptake, distribution, as well as the anticancer potential were investigated in MCF-7 and MDA-MB-231 breast cancer cells. Flash Nanoprecipitation and dynamic light scattering coupled with scanning electron microscopy were used to prepare and characterize TQ-NP prior to measuring their anticancer potential by MTT assay. The uptake and subcellular intake of TQ-NP were evaluated by fluorometry and confocal microscopy. TQ-NP were stable with a hydrodynamic average diameter size around 100 nm. Entrapment efficiency and loading content of TQ-NP were high (around 80 and 50 %, respectively). In vitro, TQ-NP had equal or enhanced anticancer activity effects compared to TQ in MCF-7 and aggressive MDA-MB-231 breast cancer cells, respectively, with no significant cytotoxicity of the blank NP. In addition, TQ and TQ-NP were relatively nontoxic to MCF-10-A normal breast cells. TQ-NP uptake mechanism was both time and concentration dependent. Treatment with inhibitors of endocytosis suggested the involvement of caveolin in TQ-NP uptake. This was further confirmed by subcellular localization findings showing the colocalization of TQ-NP with caveolin and transferrin as well as with the early and late markers of endocytosis. Altogether, the results describe an approach for the enhancement of TQ anticancer activity and uncover the mechanisms behind cell-TQ-NP interaction.

  7. Polyamines Confer Salt Tolerance in Mung Bean (Vigna radiata L.) by Reducing Sodium Uptake, Improving Nutrient Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification Systems.

    PubMed

    Nahar, Kamrun; Hasanuzzaman, Mirza; Rahman, Anisur; Alam, Md Mahabub; Mahmud, Jubayer-Al; Suzuki, Toshisada; Fujita, Masayuki

    2016-01-01

    The physiological roles of PAs (putrescine, spermidine, and spermine) were investigated for their ability to confer salt tolerance (200 mM NaCl, 48 h) in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Salt stress resulted in Na toxicity, decreased K, Ca, Mg, and Zn contents in roots and shoots, and disrupted antioxidant defense system which caused oxidative damage as indicated by increased lipid peroxidation, H2O2 content, [Formula: see text] generation rate, and lipoxygenase activity. Salinity-induced methylglyoxal (MG) toxicity was also clearly evident. Salinity decreased leaf chlorophyll (chl) and relative water content (RWC). Supplementation of salt affected seedlings with exogenous PAs enhanced the contents of glutathione and ascorbate, increased activities of antioxidant enzymes (dehydroascorbate reductase, glutathione reductase, catalase, and glutathione peroxidase) and glyoxalase enzyme (glyoxalase II), which reduced salt-induced oxidative stress and MG toxicity, respectively. Exogenous PAs reduced cellular Na content and maintained nutrient homeostasis and modulated endogenous PAs levels in salt affected mung bean seedlings. The overall salt tolerance was reflected through improved tissue water and chl content, and better seedling growth.

  8. Polyamines Confer Salt Tolerance in Mung Bean (Vigna radiata L.) by Reducing Sodium Uptake, Improving Nutrient Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification Systems

    PubMed Central

    Nahar, Kamrun; Hasanuzzaman, Mirza; Rahman, Anisur; Alam, Md. Mahabub; Mahmud, Jubayer-Al; Suzuki, Toshisada; Fujita, Masayuki

    2016-01-01

    The physiological roles of PAs (putrescine, spermidine, and spermine) were investigated for their ability to confer salt tolerance (200 mM NaCl, 48 h) in mung bean seedlings (Vigna radiata L. cv. BARI Mung-2). Salt stress resulted in Na toxicity, decreased K, Ca, Mg, and Zn contents in roots and shoots, and disrupted antioxidant defense system which caused oxidative damage as indicated by increased lipid peroxidation, H2O2 content, O2•- generation rate, and lipoxygenase activity. Salinity-induced methylglyoxal (MG) toxicity was also clearly evident. Salinity decreased leaf chlorophyll (chl) and relative water content (RWC). Supplementation of salt affected seedlings with exogenous PAs enhanced the contents of glutathione and ascorbate, increased activities of antioxidant enzymes (dehydroascorbate reductase, glutathione reductase, catalase, and glutathione peroxidase) and glyoxalase enzyme (glyoxalase II), which reduced salt-induced oxidative stress and MG toxicity, respectively. Exogenous PAs reduced cellular Na content and maintained nutrient homeostasis and modulated endogenous PAs levels in salt affected mung bean seedlings. The overall salt tolerance was reflected through improved tissue water and chl content, and better seedling growth. PMID:27516763

  9. Biochar as carrier for plant nutrients and microorganisms - techniques of agro-activation

    NASA Astrophysics Data System (ADS)

    Schmidt, H.-P.

    2012-04-01

    The soil enhancing qualities of biochar are strongly linked to its influence on nutrient cycling dynamics, sorption dynamics and to changing habitat condition for soil fauna. But as shown in multiple studies, the addition of pure biochar to agricultural soils may provoke reduced plant growth caused by the immobilisation of plant nutrients. The very potent sorption dynamics of biochar makes it an effective carrier for plant nutrients and plant-root symbiotic microorganisms. At the Delinat-Institute, we tried sundry methods of charging biochars with organic and mineral plant nutrients as well as with microorganisms. This includes the use of biochar as bulk agent in aerobic composting, in malolactic fermentation and as treatment for liquid manure, but also formulations of mineral carbon-fertilizers. Those biochar products are tested in pot and also large scale field trials. Results and experiences of these trials as well as different activation methods will be explained. A short overview of industrial designing of biochar based products will be given.

  10. 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 Central

    Malagoli, Philippe; Le Deunff, Erwan

    2014-01-01

    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. PMID:24709791

  11. Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction

    PubMed Central

    Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

    2016-01-01

    Background Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. Methods Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Results Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Conclusions Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF. PMID:27594875

  12. 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.

  13. The Interactions of Aquaporins and Mineral Nutrients in Higher Plants.

    PubMed

    Wang, Min; Ding, Lei; Gao, Limin; Li, Yingrui; Shen, Qirong; Guo, Shiwei

    2016-07-29

    Aquaporins, major intrinsic proteins (MIPs) present in the plasma and intracellular membranes, facilitate the transport of small neutral molecules across cell membranes in higher plants. Recently, progress has been made in understanding the mechanisms of aquaporin subcellular localization, transport selectivity, and gating properties. Although the role of aquaporins in maintaining the plant water status has been addressed, the interactions between plant aquaporins and mineral nutrients remain largely unknown. This review highlights the roles of various aquaporin orthologues in mineral nutrient uptake and transport, as well as the regulatory effects of mineral nutrients on aquaporin expression and activity, and an integrated link between aquaporins and mineral nutrient metabolism was identified.

  14. The Interactions of Aquaporins and Mineral Nutrients in Higher Plants

    PubMed Central

    Wang, Min; Ding, Lei; Gao, Limin; Li, Yingrui; Shen, Qirong; Guo, Shiwei

    2016-01-01

    Aquaporins, major intrinsic proteins (MIPs) present in the plasma and intracellular membranes, facilitate the transport of small neutral molecules across cell membranes in higher plants. Recently, progress has been made in understanding the mechanisms of aquaporin subcellular localization, transport selectivity, and gating properties. Although the role of aquaporins in maintaining the plant water status has been addressed, the interactions between plant aquaporins and mineral nutrients remain largely unknown. This review highlights the roles of various aquaporin orthologues in mineral nutrient uptake and transport, as well as the regulatory effects of mineral nutrients on aquaporin expression and activity, and an integrated link between aquaporins and mineral nutrient metabolism was identified. PMID:27483251

  15. The influence of hydrologic connectivity on ecosystem metabolism and nitrate uptake in an active beaver meadow

    NASA Astrophysics Data System (ADS)

    Wegener, P.; Covino, T. P.; Wohl, E.; Kampf, S. K.; Lacy, S.

    2015-12-01

    Wetlands have been widely demonstrated to provide important watershed services, such as the sequestration of carbon (C) and removal of nitrate (NO3-) from through-flowing water. Hydrologic connectivity (degree of water and associated material exchange) between floodplain water bodies (e.g., side channels, ponds) and the main channel influence rates of C accumulation and NO3- uptake, and the degree to which wetlands contribute to enhanced water quality at the catchment scale. However, environmental engineers have largely ignored the role of hydrologic connectivity in providing essential ecosystem services, and constructed wetlands are commonly built using compacted clay and berms that result in less groundwater and surface water exchange than observed in natural wetlands. In a study of an active beaver meadow (multithreaded, riparian wetland) in Rocky Mountain National Park, CO, we show how shifts in hydrology (connectivity, residence times, flow paths) from late spring snowmelt (high connectivity) to autumn/winter baseflow (low connectivity) influence ecosystem metabolism metrics (e.g., gross primary production, ecosystem respiration, and net ecosystem productivity) and NO3- uptake rates. We use a combination of mixing analyses, tracer tests, and hydrometric methods to evaluate shifts in surface and subsurface hydrologic connections between floodplain water bodies from snowmelt to baseflow. In the main channel and three floodplain water bodies, we quantify metabolism metrics and NO3- uptake kinetics across shifting flow regimes. Results from our research indicate that NO3- uptake and metabolism dynamics respond to changing levels of hydrologic connectivity to the main channel, emphasizing the importance of incorporating connectivity in wetland mitigation practices that seek to enhance water quality at the catchment scale.

  16. The activation of cannabinoid receptors in striatonigral GABAergic neurons inhibited GABA uptake.

    PubMed

    Romero, J; de Miguel, R; Ramos, J A; Fernández-Ruiz, J J

    1998-01-01

    Cannabinoid receptors (CNRs) in basal ganglia are located on striatal efferent neurons which are gamma-aminobutiric acid (GABA)-containing neurons. Recently, we have demonstrated that CN-induced motor inhibition is reversed by GABA-B, but not GABA-A, receptor antagonists, presumably indicating that the activation of CNRs in striatal outflow nuclei, mainly in the substantia nigra, should be followed by an increase of GABA concentrations into the synaptic cleft of GABA-B receptor synapses. The present study was designed to examine whether this was originated by increasing GABA synthesis and/or release or by decreasing GABA uptake. We analyzed: (i) GABA synthesis, by measuring the activity of glutamic acid decarboxylase (GAD) and GABA contents in brain regions that contain striatonigral GABAergic neurons, after in vivo administration of CNs and/or the CNR antagonist SR141716; (ii) [3H]GABA release in vitro in the presence or the absence of a synthetic CN agonist, HU-210, by using perifusion of small fragments of substantia nigra; and (iii) [3H]GABA uptake in vitro in the presence or the absence of WIN-55,212-2, by using synaptosomes obtained from either globus pallidus or substantia nigra. Results were as follows. Delta9-tetrahydrocannabinol (delta9-THC) and HU-210, did not alter neither GAD activity nor GABA contents in both the striatum and the ventral midbrain at any of the two times tested, thus suggesting that CNs apparently failed to change GABA synthesis in striatonigral GABAergic neurons. A similar lack of effect of HU-210 on in vitro [3H]GABA release, both basal and K+-evoked, was seen when this CN was added to perifused substantia nigra fragments, also suggesting no changes at the level of GABA release. However, when synaptosome preparations obtained from the substantia nigra were incubated in the presence of WIN-55,212-2, a decrease in [3H]GABA uptake could be measured. This lowering effect was specific of striatonigral GABAergic neurons since it was not

  17. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments.

    PubMed

    Kearns, Patrick J; Angell, John H; Howard, Evan M; Deegan, Linda A; Stanley, Rachel H R; Bowen, Jennifer L

    2016-09-26

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.

  18. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    NASA Astrophysics Data System (ADS)

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-09-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.

  19. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    PubMed Central

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-01-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy. PMID:27666199

  20. Prostate-Specific Membrane Antigen PET/CT: Uptake in Lymph Nodes With Active Sarcoidosis.

    PubMed

    Dias, André Henrique; Holm Vendelbo, Mikkel; Bouchelouche, Kirsten

    2017-03-01

    We describe 2 cases of Ga-PSMA PET/CT in prostate cancer patients. Both cases demonstrated symmetrical bilateral involvement of mediastinal and hilar lymph nodes besides findings in relation with prostatic disease. In both cases, endobronchial ultrasound-guided biopsy showed that the involvement of the thoracic lymph nodes was caused by nonnecrotic granulomas compatible with sarcoidosis. The cases demonstrated that increased Ga-PSMA uptake can be seen in lymph nodes with active sarcoidosis, with images mimicking those well known from FDG PET/CT. Because of these findings, granulomatous disease has to be included in the differential diagnostic evaluation of patients with Ga-PSMA-positive lymph nodes.

  1. Parallel modulation of brown adipose tissue GDP-binding, substrate uptake and (Na(+)-K+)-ATPase activity in the rat.

    PubMed

    Zamora, F; Alemany, M; Arola, L

    1991-10-01

    Brown adipose tissue (Na(+)-K+)-ATPase activity, in vitro glucose uptake and 2-aminoisobutyric acid uptake, as well as mitochondrial GDP-binding and succinate dehydrogenase activity were determined in order to study the relationship between these parameters in control, cold acclimated and cafeteria-fed rats. GDP-binding, (Na(+)-K+)-ATPase and glucose uptake were increased in interscapular brown adipose tissue from cold-acclimated and cafeteria-fed rats, whereas 2-aminoisobutyric acid uptake was only increased in cafeteria-fed rats. GDP-binding and (Na(+)-K+)-ATPase activity showed a high correlation coefficient suggesting a parallel modulation of both systems, which would probably share a common regulation mechanism.

  2. Pilot scale study on retrofitting conventional activated sludge plant for biological nutrient removal.

    PubMed

    Chiang, W W; Qasim, S R; Zhu, G; Crosby, E C

    1999-01-01

    Eutrophication of receiving waters due to the discharge of nitrogen and phosphorus through the wastewater effluent has received much interest in recent years. Numerous techniques have been proposed and aimed at retrofitting the existing conventional activated sludge process for nutrient removal. A pilot-scale research program was conducted to evaluate the effectiveness of a biological nutrient process for this purpose. The results indicated that creating an anoxic/anaerobic zone before aeration basin significantly enhances total phosphorus (TP) and total nitrogen (TN) removal. Without internal cycle, about 80 percent TP and TN removal were respectively achieved under their optimal conditions. However, adverse trends for phosphorus and nitrogen removal were observed when the ratio of return sludge to the influent was varied in the range between 0.5 and 3.0. The total phosphorus removal decreased as the concentration of BOD5 in the mixture of influent and return sludge decreased. Improved sludge settling properties and reduced foaming problems were also observed during the pilot plant operation. Based upon experimental results, the strategies to modify an existing conventional activated sludge plant into a biological nutrient removal (BNR) system are discussed.

  3. Temporal trends in nutrient ratios: chemical evidence of Mediterranean ecosystem changes driven by human activity

    NASA Astrophysics Data System (ADS)

    Béthoux, Jean P.; Morin, Pascal; Ruiz-Pino, Diana P.

    Over the last few decades, the Mediterranean ecosystem has experienced changes in biodiversity due to climatic and environmental change or to accidental inputs of exotic species. But the plankton community, which is the base of the food chain and remains only partly described, is also probably experiencing a drastic change. Observed changes in nutrient concentrations and ratios in the deep waters of the western Mediterranean, as well as differences between the eastern and western Mediterranean, suggest that shifts have occurred in the relative distribution of nutrients and therefore probably phytoplankton species over the whole sea. A shift from a diatom-dominated ecosystem to a non-siliceous one (as already observed in some coastal areas, with increasing algal blooms and eutrophication events) may involve the whole Mediterranean Sea and have consequences for fishery and tourism activities.

  4. Control of YAP/TAZ Activity by Metabolic and Nutrient-Sensing Pathways.

    PubMed

    Santinon, Giulia; Pocaterra, Arianna; Dupont, Sirio

    2016-04-01

    Metabolism is a fundamental cellular function that can be reprogrammed by signaling pathways and oncogenes to meet cellular requirements. An emerging paradigm is that signaling and transcriptional networks can be in turn regulated by metabolism, allowing cells to coordinate their metabolism and behavior in an integrated manner. The activity of the YAP/TAZ transcriptional coactivators, downstream transducers of the Hippo cascade and powerful pro-oncogenic factors, was recently found to be regulated by metabolic pathways, such as aerobic glycolysis and mevalonate synthesis, and by the nutrient-sensing LKB1-AMPK and TSC-mTOR pathways. We discuss here current data linking YAP/TAZ to metabolism and suggest how this coupling might coordinate nutrient availability with genetic programs that sustain tissue growth, neoplastic cell proliferation, and tumor malignancy.

  5. Potential enzyme activities altered by increased nutrient availability in Arctic tundra soils

    NASA Astrophysics Data System (ADS)

    Koyama, A.; Wallenstein, M. D.; Moore, J. C.; Simpson, R. T.

    2012-12-01

    The Arctic tundra is a biome affected most by global warming predicted in the future. Such warming is expected to increase nutrient availability to soil microbes which, in turn, may accelerate soil organic matter decomposition. We investigated how extra-cellular enzyme activities in soils were affected by increasing nutrient availability in an Arctic tundra ecosystem. Specifically, we measured potential activities of seven enzymes at three profiles (organic, organic/mineral interface, and mineral) of soils which had been fertilized in long- (23 years) and short-terms (six years), assayed at four temperatures. The long-term site had a high fertilization treatment (10g N m-2 year-1 and 5g P m-2 year-1) and control, and the short-term site had a low fertilization treatment (5g N m-2 year-1 and 2.5g P m-2 year-1) in addition to the high fertilization treatment and control. The fertilization treatments significantly altered most of the enzyme activities in both sites. The fertilization treatments increased activities of enzymes hydrolyzing products for C and nitrogen N sources, but decreased phosphatase activities. Such alterations were most pronounced in the organic soils. The fertilization treatments also increased ratios of total enzyme activities involved in hydrolysis for C products to those for N products. This result is consistent with an observation that long-term N and P fertilization decreased soil organic C in the same tundra ecosystem. Altered enzymatic stoichiometry with increased nutrient availability should be considered when modeling biogeochemical cycles in Arctic tundra ecosystems in response to warming predicted in the future.

  6. Carbon-Degrading Enzyme Activities Stimulated by Increased Nutrient Availability in Arctic Tundra Soils

    PubMed Central

    Koyama, Akihiro; Wallenstein, Matthew D.; Simpson, Rodney T.; Moore, John C.

    2013-01-01

    Climate-induced warming of the Arctic tundra is expected to increase nutrient availability to soil microbes, which in turn may accelerate soil organic matter (SOM) decomposition. We increased nutrient availability via fertilization to investigate the microbial response via soil enzyme activities. Specifically, we measured potential activities of seven enzymes at four temperatures in three soil profiles (organic, organic/mineral interface, and mineral) from untreated native soils and from soils which had been fertilized with nitrogen (N) and phosphorus (P) since 1989 (23 years) and 2006 (six years). Fertilized plots within the 1989 site received annual additions of 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. Within the 2006 site, two fertilizer regimes were established – one in which plots received 5 g N⋅m-2⋅year-1 and 2.5 g P⋅m-2⋅year-1 and one in which plots received 10 g N⋅m-2⋅year-1 and 5 g P⋅m-2⋅year-1. The fertilization treatments increased activities of enzymes hydrolyzing carbon (C)-rich compounds but decreased phosphatase activities, especially in the organic soils. Activities of two enzymes that degrade N-rich compounds were not affected by the fertilization treatments. The fertilization treatments increased ratios of enzyme activities degrading C-rich compounds to those for N-rich compounds or phosphate, which could lead to changes in SOM chemistry over the long term and to losses of soil C. Accelerated SOM decomposition caused by increased nutrient availability could significantly offset predicted increased C fixation via stimulated net primary productivity in Arctic tundra ecosystems. PMID:24204773

  7. Astrocytic glutamate uptake is slow and does not limit neuronal NMDA receptor activation in the neonatal neocortex.

    PubMed

    Hanson, Elizabeth; Armbruster, Moritz; Cantu, David; Andresen, Lauren; Taylor, Amaro; Danbolt, Niels Christian; Dulla, Chris G

    2015-10-01

    Glutamate uptake by astrocytes controls the time course of glutamate in the extracellular space and affects neurotransmission, synaptogenesis, and circuit development. Astrocytic glutamate uptake has been shown to undergo post-natal maturation in the hippocampus, but has been largely unexplored in other brain regions. Notably, glutamate uptake has never been examined in the developing neocortex. In these studies, we investigated the development of astrocytic glutamate transport, intrinsic membrane properties, and control of neuronal NMDA receptor activation in the developing neocortex. Using astrocytic and neuronal electrophysiology, immunofluorescence, and Western blot analysis we show that: (1) glutamate uptake in the neonatal neocortex is slow relative to neonatal hippocampus; (2) astrocytes in the neonatal neocortex undergo a significant maturation of intrinsic membrane properties; (3) slow glutamate uptake is accompanied by lower expression of both GLT-1 and GLAST; (4) glutamate uptake is less dependent on GLT-1 in neonatal neocortex than in neonatal hippocampus; and (5) the slow glutamate uptake we report in the neonatal neocortex corresponds to minimal astrocytic control of neuronal NMDA receptor activation. Taken together, our results clearly show fundamental differences between astrocytic maturation in the developing neocortex and hippocampus, and corresponding changes in how astrocytes control glutamate signaling.

  8. Simultaneous ultrastructural visualization of acetylcholinesterase activity and tritiated norepinephrine uptake in renal nerves

    SciTech Connect

    Barajas, L.; Wang, P.

    1983-02-01

    In this investigation we have combined the methods of ultrastructural demonstration of acetylcholinesterase activity with electron microscopic autoradiography for the demonstration of norepinephrine uptake. The results show electron-dense deposits indicative of acetylcholinesterase activity associated with perivascular axons overlaid by concentrations of silver grains representing exogenous tritiated norepinephrine. Forty-five percent of the intervaricose regions and 19% of the varicosities overlaid by autoradiographic grains showed ''moderate'' amounts of cholinesterase staining. A greater proportion of autoradiographic grains was observed on the varicosities than in the intervaricose regions; however, the amount of acetylcholinesterase activity was greater in the intervaricose regions than in the varicosities. This investigation provides evidence for the presence of periaxonal acetylcholinesterase staining in adrenergic axons in the rat kidney.

  9. Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin

    USGS Publications Warehouse

    O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

    2012-01-01

    Soil beneath a stormwater infiltration basin receiving runoff from a 22.7 ha predominantly residential watershed in central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop a prototype stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO3-/Cl-) ratios for the shallow groundwater indicate that prior to using BAM, NO3- concentrations were substantially influenced by nitrification or variations in NO3- input. In contrast, for the prototype basin utilizing BAM, NO3-/Cl- ratios indicate minor nitrification and NO3- losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest NO3- losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO43-) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO43-/Cl- ratios for shallow groundwater indicate predominantly minor increases and

  10. Effect of compost temperature on oxygen uptake rate, specific growth rate and enzymatic activity of microorganisms in dairy cattle manure.

    PubMed

    Miyatake, Fumihito; Iwabuchi, Kazunori

    2006-05-01

    Investigations were carried out to find out the relationship between temperature and microbial activity in dairy cattle manure composting using oxygen uptake rate, specific growth rate and enzymatic activities during autothermal and isothermal composting experiments. In autothermal composting, oxygen uptake rate and specific growth rate were found to be most intensive in order of 43 degrees C, 60 degrees C and 54 degrees C. Isothermal composting at 54 degrees C resulted highest levels of enzymatic activity and promoted the volatile solids reduction. Based on the maximum enzymatic activity, specific growth rate appeared to be more closely linked with microbial activity in compost than with oxygen uptake rate. The enhancement of specific growth rate, enzymatic activity and volatile solids reduction were induced at 54 degrees C in cattle manure composting.

  11. Nitrogen uptake and utilization by intact plants

    NASA Technical Reports Server (NTRS)

    Raper, C. D., Jr.; Tolley-Henry, L. C.

    1986-01-01

    The results of experiments support the proposed conceptual model that relates nitrogen uptake activity by plants as a balanced interdependence between the carbon-supplying function of the shoot and the nitrogen-supplying function of the roots. The data are being used to modify a dynamic simulation of plant growth, which presently describes carbon flows through the plant, to describe nitrogen uptake and assimilation within the plant system. Although several models have been proposed to predict nitrogen uptake and partitioning, they emphasize root characteristics affecting nutrient uptake and relay on empirical methods to describe the relationship between nitrogen and carbon flows within the plant. Researchers, on the other hand, propose to continue to attempt a mechanistic solution in which the effects of environment on nitrogen (as well as carbon) assimilation are incorporated through their direct effects on photosynthesis, respiration, and aging processes.

  12. A nutrient-sensitive restriction point is active during retinal progenitor cell differentiation

    PubMed Central

    Love, Nicola K.; Keshavan, Nandaki; Lewis, Rebecca; Harris, William A.; Agathocleous, Michalis

    2014-01-01

    In many growing tissues, slowly dividing stem cells give rise to rapidly proliferating progenitors that eventually exit the cell cycle and differentiate. Growth rates are limited by nutrient availability, but it is unclear which steps of the proliferation-differentiation programme are particularly sensitive to fuel supplies. We examined how nutrient deprivation (ND) affects stem and progenitor cells in the ciliary marginal zone (CMZ) of the amphibian retina, a well-characterised neurogenic niche. We show that ND specifically blocks the proliferation and differentiation of progenitor cells through an mTOR-mediated mechanism. By contrast, the identity and proliferation of retinal stem cells are insensitive to ND and mTOR inhibition. Re-feeding starved retinas in vitro rescues both proliferation and differentiation, and activation of mTOR is sufficient to stimulate differentiation even in ND retinas. These results suggest that an mTOR-mediated restriction point operates in vivo to couple nutrient abundance to the proliferation and differentiation programme in retinal progenitor cells. PMID:24449845

  13. Ammonium and nitrate uptake, nitrogen productivity and biomass allocation in interior spruce families with contrasting growth rates and mineral nutrient preconditioning.

    PubMed

    Miller, Brad D; Hawkins, Barbara J

    2007-06-01

    Four full-sib families of interior spruce (Picea glauca (Moench) Voss) x Picea engelmanii Parry ex Engelm.) with contrasting growth rates (two fast-growing and two slow-growing families) were grown aeroponically with either a 2% relative nitrogen addition rate or free access to nitrogen. Fast-growing families showed greater plasticity in allocating biomass to shoots at high nitrogen supply and to roots at low nitrogen supply than slow-growing families. Compared with the slow-growing families, short-term net ammonium uptake rate measured with an ion selective electrode was significantly greater in fast-growing families at high ammonium supply, but not at low supply. Net nitrate uptake showed the same trend, but differences among families were not significant. Results indicate that differences in seedling growth rate are partly a result of physiological differences in net nitrogen uptake efficiency and nitrogen productivity.

  14. Carbon Monoxide Fumigation Improved the Quality, Nutrients, and Antioxidant Activities of Postharvest Peach

    PubMed Central

    Li, Ying; Pei, Fei

    2014-01-01

    Peaches (Prunus persica cv. Yanhong) were fumigated with carbon monoxide (CO) at 0, 0.5, 5, 10, and 20 μmol/L for 2 hours. The result showed that low concentration CO (0.5–10 μmol/L) might delay the decrease of firmness and titrable acid content, restrain the increase of decay incidence, and postpone the variation of soluble solids content, but treating peaches with high concentration CO (20 μmol/L) demonstrated adverse effects. Further research exhibited that exogenous CO could induce the phenylalnine ammonialyase activity, maintain nutrient contents such as Vitamin C, total flavonoid, and polyphenol, and enhance antioxidant activity according to reducing power and 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl radical scavenging activity. Treating peaches with appropriate concentration CO was beneficial to the quality, nutrients, and antioxidant activity of postharvest peaches during storage time. Therefore, CO fumigation might probably become a novel method to preserve postharvest peach and other fruits in the future. PMID:26904651

  15. Regulation of AMPK Activation by CD36 Links Fatty Acid Uptake to β-Oxidation

    PubMed Central

    Sun, Jingyu; Pietka, Terri; Gross, Richard W.; Eckel, Robert H.; Su, Xiong; Stahl, Philip D.

    2015-01-01

    Increases in muscle energy needs activate AMPK and induce sarcolemmal recruitment of the fatty acid (FA) translocase CD36. The resulting rises in FA uptake and FA oxidation are tightly correlated, suggesting coordinated regulation. We explored the possibility that membrane CD36 signaling might influence AMPK activation. We show, using several cell types, including myocytes, that CD36 expression suppresses AMPK, keeping it quiescent, while it mediates AMPK activation by FA. These dual effects reflect the presence of CD36 in a protein complex with the AMPK kinase LKB1 (liver kinase B1) and the src kinase Fyn. This complex promotes Fyn phosphorylation of LKB1 and its nuclear sequestration, hindering LKB1 activation of AMPK. FA interaction with CD36 dissociates Fyn from the protein complex, allowing LKB1 to remain cytosolic and activate AMPK. Consistent with this, CD36−/− mice have constitutively active muscle and heart AMPK and enhanced FA oxidation of endogenous triglyceride stores. The molecular mechanism described, whereby CD36 suppresses AMPK, with FA binding to CD36 releasing this suppression, couples AMPK activation to FA availability and would be important for the maintenance of cellular FA homeostasis. Its dysfunction might contribute to the reported association of CD36 variants with metabolic complications of obesity in humans. PMID:25157091

  16. Estrogenic activity and nutrient losses in surface runoff after winter manure application to small watersheds.

    PubMed

    Shappell, N W; Billey, L O; Shipitalo, M J

    2016-02-01

    Confined Animal Feeding Operations generate large amounts of wastes that are land-applied to provide nutrients for crop production and return organic matter to the soil. Production practices and storage limitations often necessitate that wastes be applied to frozen and snow-covered soil. Use of application setbacks have reduced concerns related to nutrient losses in surface runoff from manure, but the estrogenic activity of runoff under these conditions has not been evaluated. Therefore, we measured and sampled surface runoff when manure was applied in the winter at a rate to meet crop N needs and measured estradiol equivalents (E2Eqs) using E-Screen. In year one, six small watersheds used to produce corn were evaluated, treatments: 2 no-manure controls, 2 liquid swine manure with 30-m setbacks, and 2 turkey litter with 30-m setbacks. In addition, beef manure was applied to six frozen plots of forage. For years 2 and 3, applications were repeated on the swine manure watersheds and one control watershed. E2Eqs and nutrient concentrations generally peaked in the first runoff event after application. The highest measured E2Eq (5.6 ng L(-1)) was in the first event after swine manure application and was less than the 8.9 ng L(-1) Lowest Observable Effect Concentration (LOEC) for aquatic species and well below the concentrations measured in other studies using ELISAs to measure hormone concentrations. No runoff occurred from plots planted with forage, indicating low risk for environmental impact, and therefore plots were discontinued from study. In years 2 and 3, estrogenic activity never exceeded the Predicted No Effect Concentrations for E2 of 2 ng L(-1). When post-application runoff contained high estrogenic activity, strong correlations (R(2) 0.86 to 0.96) of E2Eq to Ca(2+), Mg(2+), and K(+) concentrations were observed, indicating under some condition these cations might be useful surrogates for E2Eq measurements.

  17. Dehydroascorbate uptake activity correlates with cell growth and cell division of tobacco bright yellow-2 cell cultures.

    PubMed

    Horemans, Nele; Potters, Geert; De Wilde, Leen; Caubergs, Roland J

    2003-09-01

    Recently, ascorbate (ASC) concentration and the activity of a number of enzymes from the ASC metabolism have been proven to correlate with differences in growth or cell cycle progression. Here, a possible correlation between growth and the activity of a plasma membrane dehydroascorbate (DHA) transporter was investigated. Protoplasts were isolated from a tobacco (Nicotiana tabacum) Bright Yellow-2 cell culture at different intervals after inoculation and the activity of DHA transport was tested with (14)C-labeled ASC. Ferricyanide (1 mM) or dithiothreitol (1 mM) was included in the test to keep the external (14)C-ASC in its oxidized respectively reduced form. Differential uptake activity was observed, correlating with growth phases of the cell culture. Uptake of DHA in cells showed a peak in exponential growth phase, whereas uptake in the presence of dithiothreitol did not. The enhanced DHA uptake was not due to higher endogenous ASC levels that are normally present in exponential phase because preloading of protoplasts of different ages did not affect DHA uptake. Preloading was achieved by incubating cells before protoplastation for 4 h in a medium supplemented with 1 mM DHA. In addition to testing cells at different growth phases, uptake of DHA into the cells was also followed during the cell cycle. An increase in uptake activity was observed during M phase and the M/G1 transition. These experiments are the first to show that DHA transport activity into plant cells differs with cell growth. The relevance of the data to the action of DHA and ASC in cell growth will be discussed.

  18. Scavenger receptor B1 facilitates macrophage uptake of silver nanoparticles and cellular activation

    NASA Astrophysics Data System (ADS)

    Aldossari, Abdullah A.; Shannahan, Jonathan H.; Podila, Ramakrishna; Brown, Jared M.

    2015-07-01

    Due to increased use of silver nanoparticles (AgNPs) for their antimicrobial activity, concerns have risen regarding potential adverse human health effects. Scavenger receptor B1 (SR-B1), a major receptor for high-density lipoprotein (HDL), is expressed by macrophages and has also been reported to play a role in recognition of negatively charged particles. We, therefore, hypothesized that SR-B1 mediates macrophage uptake of AgNPs and inflammatory activation. To test this hypothesis, we exposed a mouse macrophage cell line RAW264.7 (RAW) and bone marrow-derived macrophages (BMDM) to 20 nm citrate-suspended AgNPs. To verify the role of the SR-B1 receptor, we utilized a SR-B1 inhibitor (Blt2). In vitro studies demonstrated uptake of AgNPs and HDL-coated AgNPs by macrophages which were significantly reduced following pretreatment with Blt2. Inflammatory cytokine arrays revealed that macrophages exposed to AgNPs up-regulated expression of Tnf- α, Oncostatin m (OSM), Ccl4, Il17f, Ccl7, and Ccl2, whereas Il16 was found to be down-regulated. Macrophage activation was observed following AgNP and HDL-coated AgNP exposure as measured by OSM protein production and increased surface expression of CD86. These markers of activation were reduced with Blt2 pretreatment. The in vitro findings were confirmed in vivo through pulmonary instillation of AgNPs in mice. Pulmonary instillation of AgNPs resulted in a recruitment of inflammatory cells that were reduced in SR-B1-deficient mice or following Blt2 pretreatment. This study suggests that SR-B1 plays a major role in cellular recognition of AgNPs and the induction of cell responses that could contribute to inflammation caused by AgNP exposure.

  19. PAR1 activation induces rapid changes in glutamate uptake and astrocyte morphology

    PubMed Central

    Sweeney, Amanda M.; Fleming, Kelsey E.; McCauley, John P.; Rodriguez, Marvin F.; Martin, Elliot T.; Sousa, Alioscka A.; Leapman, Richard D.; Scimemi, Annalisa

    2017-01-01

    The G-protein coupled, protease-activated receptor 1 (PAR1) is a membrane protein expressed in astrocytes. Fine astrocytic processes are in tight contact with neurons and blood vessels and shape excitatory synaptic transmission due to their abundant expression of glutamate transporters. PAR1 is proteolytically-activated by bloodstream serine proteases also involved in the formation of blood clots. PAR1 activation has been suggested to play a key role in pathological states like thrombosis, hemostasis and inflammation. What remains unclear is whether PAR1 activation also regulates glutamate uptake in astrocytes and how this shapes excitatory synaptic transmission among neurons. Here we show that, in the mouse hippocampus, PAR1 activation induces a rapid structural re-organization of the neuropil surrounding glutamatergic synapses, which is associated with faster clearance of synaptically-released glutamate from the extracellular space. This effect can be recapitulated using realistic 3D Monte Carlo reaction-diffusion simulations, based on axial scanning transmission electron microscopy (STEM) tomography reconstructions of excitatory synapses. The faster glutamate clearance induced by PAR1 activation leads to short- and long-term changes in excitatory synaptic transmission. Together, these findings identify PAR1 as an important regulator of glutamatergic signaling in the hippocampus and a possible target molecule to limit brain damage during hemorrhagic stroke. PMID:28256580

  20. Evaluating the uptake of Canada's new physical activity and sedentary behavior guidelines on service organizations' websites.

    PubMed

    Gainforth, Heather L; Berry, Tanya; Faulkner, Guy; Rhodes, Ryan E; Spence, John C; Tremblay, Mark S; Latimer-Cheung, Amy E

    2013-06-01

    New evidence-based physical activity and sedentary behavior guidelines for Canadians were launched in 2011. As a consequence, service organizations that promote physical activity directly to the public needed to change their promotion materials to reflect the new guidelines. Little is known about the rate at which service organizations adopt and integrate new evidence-based guidelines and determinants of guideline adoption. In this natural observational study, we evaluated the rate of online adoption of the new guidelines among key service organizations that promote physical activity and examined participation in a booster webinar as a supplemental dissemination strategy. One hundred fifty nine service organization websites were coded by one of six raters prior to the release of the new guidelines as well as at 3, 6, and 9 months after the release. Online adoption of the guidelines increased during the coding period with 51 % of organizations posting the guidelines or related information on their websites. Organizations' engagement in a webinar was associated with their adoption of the guidelines. The release of new Canadian Physical Activity and Sedentary Behaviour Guidelines led to increased guideline adoption on service organizations' websites. However, adoption was not universal. In order for the uptake of the new guidelines to be successful, further efforts need to be taken to ensure that service organizations present physical activity guidelines on their websites. Comprehensive, active dissemination strategies tailored to address organizational barriers are needed to ensure online guideline adoption.

  1. Nitrate uptake improvement by modified activated carbons developed from two species of pine cones.

    PubMed

    Nunell, G V; Fernandez, M E; Bonelli, P R; Cukierman, A L

    2015-02-15

    Activated carbons from two species of pine cones (Pinus canariensis and Cupressus sempervirens) were prepared by phosphoric acid activation and tested for the removal of nitrate ions from aqueous solution. To investigate the feasibility of improving their nitrate adsorption capacity, two different post-treatments—a thermal treatment and a treatment with saturated urea solution—were also applied to the prepared activated carbons. Comparison of the treated and untreated activated carbons showed that both post-treatments improved the nitrate adsorption performance more than twice. The maximum adsorption capacity, as evaluated from determination of the adsorption isotherms for the P. canariensis based carbons, and their proper representation by the Langmuir model, demonstrated that the post-treatment with the urea solution led to activated carbons with increased nitrate removal effectiveness, even superior to other reported results. Enhancements in their adsorption capacity could be mainly ascribed to higher contents of nitrogen and basic functional groups, whereas porous structure of the activated carbons did not seem to play a key role in the nitrate uptake.

  2. The interrelationship between muscle oxygenation, muscle activation, and pulmonary oxygen uptake to incremental ramp exercise: influence of aerobic fitness.

    PubMed

    Boone, Jan; Barstow, Thomas J; Celie, Bert; Prieur, Fabrice; Bourgois, Jan

    2016-01-01

    We investigated whether muscle and ventilatory responses to incremental ramp exercise would be influenced by aerobic fitness status by means of a cross-sectional study with a large subject population. Sixty-four male students (age: 21.2 ± 3.2 years) with a heterogeneous peak oxygen uptake (51.9 ± 6.3 mL·min(-1)·kg(-1), range 39.7-66.2 mL·min(-1)·kg(-1)) performed an incremental ramp cycle test (20-35 W·min(-1)) to exhaustion. Breath-by-breath gas exchange was recorded, and muscle activation and oxygenation were measured with surface electromyography and near-infrared spectroscopy, respectively. The integrated electromyography (iEMG), mean power frequency (MPF), deoxygenated [hemoglobin and myoglobin] (deoxy[Hb+Mb]), and total[Hb+Mb] responses were set out as functions of work rate and fitted with a double linear function. The respiratory compensation point (RCP) was compared and correlated with the breakpoints (BPs) (as percentage of peak oxygen uptake) in muscle activation and oxygenation. The BP in total[Hb+Mb] (83.2% ± 3.0% peak oxygen uptake) preceded (P < 0.001) the BP in iEMG (86.7% ± 4.0% peak oxygen uptake) and MPF (86.3% ± 4.1% peak oxygen uptake), which in turn preceded (P < 0.01) the BP in deoxy[Hb+Mb] (88.2% ± 4.5% peak oxygen uptake) and RCP (87.4% ± 4.5% peak oxygen uptake). Furthermore, the peak oxygen uptake was significantly (P < 0.001) positively correlated to the BPs and RCP, indicating that the BPs in total[Hb+Mb] (r = 0.66; P < 0.001), deoxy[Hb+Mb] (r = 0.76; P < 0.001), iEMG (r = 0.61; P < 0.001), MPF (r = 0.63; P < 0.001), and RCP (r = 0.75; P < 0.001) occurred at a higher percentage of peak oxygen uptake in subjects with a higher peak oxygen uptake. In this study a close relationship between muscle oxygenation, activation, and pulmonary oxygen uptake was found, occurring in a cascade of events. In subjects with a higher aerobic fitness level this cascade occurred at a higher relative intensity.

  3. On the Water Uptake and CCN Activation of Tropospheric Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Rastak, Narges; Pajunoja, Aki; Acosta Navarro, Juan-Camilo; Leong, Yu Jun; Cerully, Kate M.; Nenes, Athanasios; Kirkevåg, Alf; Topping, David; Virtanen, Annele; Riipinen, Ilona

    2016-04-01

    Aerosol particles introduce high uncertainties to radiative climate forcing. If exposed to a given relative humidity (RH), aerosol particles containing soluble material can absorb water and grow in size (hygroscopic growth). If RH is increased further beyond supersaturation (RH >100%) the particles can act as cloud condensation nuclei (CCN). Aerosol particles interactions with water vapour determine to a large extent their influence on climate. Organic aerosols (OA) contribute a large fraction (20-90%) of atmospheric submicron particulate mass, on the other hand they often consist of thousands of compounds with different properties. One of these properties is solubility, which affects the hygroscopic growth and cloud condensation nucleus (CCN) activation of the organic particles. We investigate the hygroscopic behaviour of complex organic aerosols accounting for the distribution of solubilities present in these mixtures. We use the SPARC method to estimate the solubility distributions of isoprene (IP) and monoterpene (MT) SOA based on their chemical composition, as predicted by the Master Chemical Mechanism (MCM). Combining these solubility distributions with the adsorption theory along with the non-ideal behaviour of organic mixtures, we predict the expected hygroscopic growth factors (HGFs), CCN activation behaviour and the related hygroscopicity parameters kappa for these mixtures. The predictions are compared to laboratory measurements as well as field data from MT- and IP-dominated measurement sites. The predicted solubility distributions do a good job in explaining the water uptake of these two mixture types at high relative humidities (RH around 90%), as well as their CCN activation - including the potential differences between the kappa values derived from HGF vs. CCN data. At lower relative humidities, however, the observed water uptake is higher than predicted on solubility alone, particularly for the MT-derived SOA. The data from the low RHs are further

  4. Apolipoprotein D Transgenic Mice Develop Hepatic Steatosis through Activation of PPARγ and Fatty Acid Uptake

    PubMed Central

    Labrie, Marilyne; Lalonde, Simon; Najyb, Ouafa; Thiery, Maxime; Daneault, Caroline; Des Rosiers, Chrisitne; Rassart, Eric; Mounier, Catherine

    2015-01-01

    Transgenic mice (Tg) overexpressing human apolipoprotein D (H-apoD) in the brain are resistant to neurodegeneration. Despite the use of a neuron-specific promoter to generate the Tg mice, they expressed significant levels of H-apoD in both plasma and liver and they slowly develop hepatic steatosis and insulin resistance. We show here that hepatic PPARγ expression in Tg mice is increased by 2-fold compared to wild type (WT) mice. Consequently, PPARγ target genes Plin2 and Cide A/C are overexpressed, leading to increased lipid droplets formation. Expression of the fatty acid transporter CD36, another PPARgamma target, is also increased in Tg mice associated with elevated fatty acid uptake as measured in primary hepatocytes. Elevated expression of AMPK in the liver of Tg leads to phosphorylation of acetyl CoA carboxylase, indicating a decreased activity of the enzyme. Fatty acid synthase expression is also induced but the hepatic lipogenesis measured in vivo is not significantly different between WT and Tg mice. In addition, expression of carnitine palmitoyl transferase 1, the rate-limiting enzyme of beta-oxidation, is slightly upregulated. Finally, we show that overexpressing H-apoD in HepG2 cells in presence of arachidonic acid (AA), the main apoD ligand, increases the transcriptional activity of PPARγ. Supporting the role of apoD in AA transport, we observed enrichment in hepatic AA and a decrease in plasmatic AA concentration. Taken together, our results demonstrate that the hepatic steatosis observed in apoD Tg mice is a consequence of increased PPARγ transcriptional activity by AA leading to increased fatty acid uptake by the liver. PMID:26083030

  5. Spatial distribution of microorganisms and measurements of oxygen uptake rate and ammonia uptake rate activity in a drinking water biofilter.

    PubMed

    Madoni, P; Davoli, D; Fontani, N; Cucchi, A; Rossi, F

    2001-04-01

    The biofilm characteristics (population dynamics and biofilm composition) in a biological filter for the removal of iron, manganese and ammonium were studied in a drinking water treatment plant. The objective was to examine the spatial distribution and biological composition of active biomass that grows in a biological filter and to verify the effect of the backwashing on the quantity of fixed biomass and on the density and activity of the biological population. Heterotrophic microorganisms activity was higher in the upper layer of the filter. Nitrifying microorganisms colonized the biofilter in a stratified manner and their activity was higher in the second layer of the filter. A total of 14 species of ciliated protozoa and 7 species of filamentous microorganisms were found in the biofilters. Ciliates were concentrated in the filterbed layer in which the heterotrophic activity was higher. The grazing activity of ciliates on heterotrophic bacteria reduced the competition pressure on nitrifying microorganisms, supporting their growth and thus raising the ammonium removal efficiency. In general, filamentous microorganisms appeared to be indifferent to operating changes in the plant such as backwashing and filtering cycles. Crenothrix was the prevalent filamentous microorganism in terms of both frequency and abundance; it was found prevalently in the first layer where the oxidisation of iron and manganese occurred.

  6. Metaproteogenomics reveals the soil microbial communities active in nutrient cycling processes under different tree species

    NASA Astrophysics Data System (ADS)

    Keiblinger, Katharina Maria; Masse, Jacynthe; Zühlke, Daniela; Riedel, Katharina; Zechmeister-Boltenstern, Sophie; Prescott, Cindy E.; Grayston, Sue

    2016-04-01

    Tree species exert strong effects on microbial communities in litter and soil and may alter rates of soil processes fundamental to nutrient cycling and carbon fluxes (Prescott and Grayston 2013). However, the influence of tree species on decomposition processes are still contradictory and poorly understood. An understanding of the mechanisms underlying plant influences on soil processes is important for our ability to predict ecosystem response to altered global/environmental conditions. In order to link microbial community structure and function to forest-floor nutrient cycling processes, we sampled forest floors under western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii) and Sitka spruce (Picea sitchensis) grown in nutrient-poor sites in common garden experiments on Vancouver island (Canada). We measured forest-floor total N, total C, initial NH4+ and NO3- concentrations, DOC, Cmic and Nmic. Gross rates of ammonification and NH4+ consumption were measured using the 15N pool-dilution method. Organic carbon quality was assessed through FTIR analyses. Microbial community structure was analysed by a metaproteogenomic approach using 16S and ITS amplification and sequencing with MiSeq platform. Proteins were extracted and peptides characterized via LC-MS/MS on a Velos Orbitrap to assess the active microbial community. Different microbial communities were active under the three tree species and variation in process rates were observed and will be discussed. This research provides new insights on microbial processes during organic matter decomposition. The metaproteogenomic approach enables us to investigate these changes with respect to possible effects on soil C-storage at even finer taxonomic resolution.

  7. Alcohol dehydrogenase activity in Lactococcus chungangensis: application in cream cheese to moderate alcohol uptake.

    PubMed

    Konkit, Maytiya; Choi, Woo Jin; Kim, Wonyong

    2015-09-01

    Many human gastrointestinal facultative anaerobic and aerobic bacteria possess alcohol dehydrogenase (ADH) activity and are therefore capable of oxidizing ethanol to acetaldehyde. However, the ADH activity of Lactococcus spp., except Lactococcus lactis ssp. lactis, has not been widely determined, though they play an important role as the starter for most cheesemaking technologies. Cheese is a functional food recognized as an aid to digestion. In the current study, the ADH activity of Lactococcus chungangensis CAU 28(T) and 11 reference strains from the genus Lactococcus was determined. Only 5 strains, 3 of dairy origin, L. lactis ssp. lactis KCTC 3769(T), L. lactis ssp. cremoris KCCM 40699(T), and Lactococcus raffinolactis DSM 20443(T), and 2 of nondairy origin, Lactococcus fujiensis NJ317(T) and Lactococcus chungangensis CAU 28(T) KCTC 13185(T), showed ADH activity and possessed the ADH gene. All these strains were capable of making cheese, but the highest level of ADH activity was found in L. chungangensis, with 45.9nmol/min per gram in tryptic soy broth and 65.8nmol/min per gram in cream cheese. The extent that consumption of cheese, following imbibing alcohol, reduced alcohol uptake was observed by following the level of alcohol in the serum of mice. The results show a potential novel benefit of cheese as a dairy functional food.

  8. Sensing of energy and nutrients by AMP-activated protein kinase.

    PubMed

    Hardie, D Grahame

    2011-04-01

    AMP-activated protein kinase (AMPK) is a cellular energy sensor that exists in almost all eukaryotes. Genetic studies in lower eukaryotes suggest that the ancestral role of AMPK was in response to starvation for a carbon source and that AMPK is involved in life-span extension in response to caloric restriction. In mammals, AMPK is activated by an increasing cellular AMP:ATP ratio (which signifies a decrease in energy) caused by metabolic stresses that interfere with ATP production (eg, hypoxia) or that accelerate ATP consumption (eg, muscle contraction). Because glucose deprivation can increase the AMP:ATP ratio, AMPK can also act as a glucose sensor. AMPK activation occurs by a dual mechanism that involves allosteric activation and phosphorylation by upstream kinases. Once activated, AMPK switches on catabolic pathways that generate ATP (eg, the uptake and oxidation of glucose and fatty acids and mitochondrial biogenesis) while switching off ATP-consuming, anabolic pathways (eg, the synthesis of lipids, glucose, glycogen, and proteins). In addition to the acute effects via direct phosphorylation of metabolic enzymes, AMPK has longer-term effects by regulating transcription. These features make AMPK an ideal drug target in the treatment of metabolic disorders such as insulin resistance and type 2 diabetes. The antidiabetic drug metformin (which is derived from an herbal remedy) works in part by activating AMPK, whereas many xenobiotics or "nutraceuticals," including resveratrol, quercetin, and berberine, are also AMPK activators. Most of these agents activate AMPK because they inhibit mitochondrial function.

  9. Brown adipose tissue (Na+-K+)-ATPase activity and substrate uptake during the breeding cycle of rats.

    PubMed

    Zamora, F; Arola, L

    1989-05-01

    Brown adipose tissue (Na+-K+)-ATPase activity, in vitro glucose and 2-aminoisobutyric acid uptake, as well as mitochondrial GDP-binding and succinate dehydrogenase activity were determined in order to study the relationship between these parameters and the thermogenic status. Analysis were carried out on control animal, pregnant rats, dams and pups during lactation, GDP-binding, (Na+-K+)-ATPase and glucose uptake were found to be decreased in brown adipose tissue from pregnant rats and dams, and increased in pups, 2-aminoisobutyric acid uptake was only increased in pups, but no changes were observed in the other experimental groups tested. GDP-binding and (Na+-K+)-ATPase activity showed a parallelism which suggests that the enzyme is a good index of thermogenic status of the animal.

  10. Measuring the activities of higher organisms in activated sludge by means of mechanical shearing pretreatment and oxygen uptake rate.

    PubMed

    Hao, Xiaodi; Wang, Qilin; Cao, Yali; van Loosdrecht, Mark C M

    2010-07-01

    A pretreatment method was developed to assess the activities of higher organisms. The method is based on mechanical shearing to damage the large cells of the protozoan and metazoan community in activated sludge. The procedure was confirmed through experimentation to be effective in determining the activities of higher organisms by comparing oxygen uptake rates (OURs) before and after the higher organisms were eradicated. Shearing led to disintegration of flocs, which could be effectively reconstituted by centrifugation. The reconstitution of the sludge flocs was essential since otherwise the activity of the floc mass would be too high due to lack of diffusion limitation. Mechanical shearing had no influence on the morphology, quantity and specific activity of yeasts, and it was inferred that bacteria smaller than yeasts in size would also not be influenced by the applied shearing procedure. Moreover, the effect of filamentous organisms on the measured activities of higher organisms was experimentally demonstrated and analyzed, and determined to be so weak that it could be ignored. Based on these tests, five typical activated sludge processes were selected to measure the contribution of higher organisms to the original OUR. The measured activities of higher organisms ranged from 9.4 to 25.0% of the original OURs.

  11. Iodomethylnorcholesterol uptake in an aldosteronoma shown by dexamethasone-suppression scintigraphy: Relationship to adenoma size and functional activity

    SciTech Connect

    Nomura, K.; Kusakabe, K.; Maki, M.; Ito, Y.; Aiba, M.; Demura, H. )

    1990-10-01

    Dexamethasone-suppression (DS) adrenal scintigraphy localizes an aldosteronoma, but with false-negative results, i.e. 2 of 19 cases in our study. Our aim was to clarify the clinical meaningfulness of this test. Adrenal iodomethyl-norcholesterol (NP-59) uptake on the adenoma side correlated with the estimated adenoma volume (n = 15, r = 0.843, P less than 0.001). Accordingly, the uptake ratio on the adenoma side to that on the opposite side depended on the adenoma volume (r = 0.683, P less than 0.01). This explains the false-negative results (uptake ratio less than 2) in two cases with small adenomas. The NP-59 uptake correlated weakly with the plasma aldosterone level (r = 0.516, P less than 0.05). This result indicates the low correlation between NP-59 uptake and the ability to secrete aldosterone. NP-59 accumulation in the surgically removed gland was analyzed by autoradiography in six cases where DS scintigraphy was done just before surgery. The density was higher in the adenoma cells than in the adjacent cortical cells in five cases, but the difference was rather small, i.e., within a 2-fold difference in four cases. In one case, almost the same density was observed in both types of cells. Thus, the laterality of NP-59 uptake primarily depends on the adenoma volume although NP-59 uptake somewhat reflects the adenoma's ability to secrete aldosterone or the adenoma cell's activity in accumulating NP-59. Care must be taken in interpreting the findings from DS scintigraphy where the adenoma is small or adrenal uptake is low.

  12. Vibrational imaging of glucose uptake activity in live cells and tissues by stimulated Raman scattering microscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hu, Fanghao; Chen, Zhixing; Zhang, Luyuan; Shen, Yihui; Wei, Lu; Min, Wei

    2016-03-01

    Glucose is consumed as an energy source by virtually all living organisms, from bacteria to humans. Its uptake activity closely reflects the cellular metabolic status in various pathophysiological transformations, such as diabetes and cancer. Extensive efforts such as positron emission tomography, magnetic resonance imaging and fluorescence microscopy have been made to specifically image glucose uptake activity but all with technical limitations. Here, we report a new platform to visualize glucose uptake activity in live cells and tissues with subcellular resolution and minimal perturbation. A novel glucose analogue with a small alkyne tag (carbon-carbon triple bond) is developed to mimic natural glucose for cellular uptake, which can be imaged with high sensitivity and specificity by targeting the strong and characteristic alkyne vibration on stimulated Raman scattering (SRS) microscope to generate a quantitative three dimensional concentration map. Cancer cells with differing metabolic characteristics can be distinguished. Heterogeneous uptake patterns are observed in tumor xenograft tissues, neuronal culture and mouse brain tissues with clear cell-cell variations. Therefore, by offering the distinct advantage of optical resolution but without the undesirable influence of bulky fluorophores, our method of coupling SRS with alkyne labeled glucose will be an attractive tool to study energy demands of living systems at the single cell level.

  13. Influence of anionic surface-active agents on the uptake of heavy metals by water hyacinth (Eichhornia crassipes)

    SciTech Connect

    Muramoto, S.; Oki, Y.

    1984-10-01

    In a previous paper, the ability of water hyacinth to remove toxic heavy metals, cadmium, lead, and mercury, from a metal-containing solution was reported. However, information on the effects of surface-active agents on the metal uptake from waste water by water hyacinth is insufficient. Surface-active agents including anionic detergents have been found in lake, ponds, and rivers polluted by waste from industry and municipal sewage treatment plants. The present study examines the uptake of cadmium or nickel in the presence of the anionic detergent sodium dedecyl sulfate.

  14. Effects of Nutrient Addition on Belowground Stoichiometry and Microbial Activity in an Ombrotrophic Bog

    NASA Astrophysics Data System (ADS)

    Pinsonneault, A. J.; Moore, T. R.; Roulet, N. T.

    2015-12-01

    Ombrotrophic bogs are both nutrient-poor systems and important carbon (C) sinks yet there remains a dearth of information on the stoichiometry of C, nitrogen (N), phosphorus (P), and potassium (K), an important determinant of substrate quality for microorganisms, in these systems. In this study, we quantified the C, N, P, and K concentrations and stoichiometric ratios of both soil organic matter (SOM) and dissolved organic matter (DOM) as well as microbial extracellular enzyme activity from 0 - 10cm depth in a long-term fertilization experiment at Mer Bleue bog, Ontario, Canada. Though trends in C:N, C:P, and C:K between SOM and DOM seem to follow one another, preliminary results indicate that the stoichiometric ratios of DOM were at least an order of magnitude smaller than those of DOM suggesting that nutrient fertilization impacts the quality of DOM as a microbial substrate to a greater degree than SOM. C:N decreased with greater nitrogen addition but C:P and C:K increased; the magnitude of that increase being smaller in NPK treatments relative to N-only treatments suggesting co-limitation by P and/or K. This is further supported by the increase in activity of both the C-cycling enzyme, β-D-glucosidase (bdG), and the P-cycling enzyme, phosphatase (Phos), with greater nitrogen addition; particularly in NPK-treatments for bdG and N-only treatments for Phos. The activity of the N-cycling enzyme, N-acetyl-β-D-glucosaminidase, and the C-cycling enzyme, phenol oxidase, with greater N-addition suggests a decreased need to breakdown organic nitrogen to meet microbial N-requirements in the former and N-inhibition in the latter consistent with findings in the literature. Taken together, these results suggest that higher levels of nutrients impact both microbial substrate quality as well as the activity of microbial enzymes that are key in the decomposition process which may ultimately decrease the ability of peatlands to sequester carbon.

  15. Precise quantification of cellular uptake of cell-penetrating peptides using fluorescence-activated cell sorting and fluorescence correlation spectroscopy.

    PubMed

    Rezgui, Rachid; Blumer, Katy; Yeoh-Tan, Gilbert; Trexler, Adam J; Magzoub, Mazin

    2016-07-01

    Cell-penetrating peptides (CPPs) have emerged as a potentially powerful tool for drug delivery due to their ability to efficiently transport a whole host of biologically active cargoes into cells. Although concerted efforts have shed some light on the cellular internalization pathways of CPPs, quantification of CPP uptake has proved problematic. Here we describe an experimental approach that combines two powerful biophysical techniques, fluorescence-activated cell sorting (FACS) and fluorescence correlation spectroscopy (FCS), to directly, accurately and precisely measure the cellular uptake of fluorescently-labeled molecules. This rapid and technically simple approach is highly versatile and can readily be applied to characterize all major CPP properties that normally require multiple assays, including amount taken up by cells (in moles/cell), uptake efficiency, internalization pathways, intracellular distribution, intracellular degradation and toxicity threshold. The FACS-FCS approach provides a means for quantifying any intracellular biochemical entity, whether expressed in the cell or introduced exogenously and transported across the plasma membrane.

  16. Peroxynitrite activates glucose uptake in 3T3-L1 adipocytes through a PI3-K-dependent mechanism.

    PubMed

    Guzman-Grenfell, Alberto M; Garcia-Macedo, Rebeca; Gonzalez-Martinez, Marco T; Hicks, Juan Jose; Medina-Navarro, Rafael

    2005-01-01

    Peroxynitrite, the product of the reaction between *NO and O2*-, is a strong oxidant and nitrating molecule, and it has been recently consideredas a component of some important signaling pathways. Herein, we report the effect of peroxynitrite on glucose uptake in 3T3-L1 adipocytes. Peroxynitrite stimulated glucose uptake and this effect was inhibited by citochalasin B, indicating the participation of facilitated GLUT transporters. Peroxynitrite-induced glucose uptake was not related to intracellular ATP, nor to external or internal calcium, but it was inhibited by the phosphatidylinositol 3-kinase (PI3-K) inhibitor, wortmannin. Additionally, we also found that peroxynitrite did not activate the insulin receptor nor the PI3-K downstream signaling protein kinase B (PKB/Akt). The dose-dependent inhibitory action of wortmannin suggests that peroxynitrite activates glucose transport without affecting GLUT transporters translocation.

  17. Active Uptake of Amino Acids by Leaves of an Epiphytic Vascular Plant, Tillandsia paucifolia (Bromeliaceae) 1

    PubMed Central

    Nyman, Leslie Paul; Davis, James P.; O'Dell, Stephen J.; Arditti, Joseph; Stephens, Grover C.; Benzing, David H.

    1987-01-01

    Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 104. Images Fig. 2 Fig. 3 PMID:16665307

  18. Enhancement and inhibition of microbial activity in hydrocarbon- contaminated arctic soils: Implications for nutrient-amended bioremediation

    USGS Publications Warehouse

    Braddock, J.F.; Ruth, M.L.; Catterall, P.H.; Walworth, J.L.; McCarthy, K.A.

    1997-01-01

    Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) end low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus. When nutrients were added to soil in the field at three levels of N:P (100:45, 200:90, and 300:135 mg/kg soil), the greatest stimulation in microbial activity occurred at the lowest, rather than the highest, level of nutrient addition. The total soil-water potentials ranged from -2 to -15 bar with increasing levels of fertilizer. Semivolatile hydrocarbon concentrations declined significantly only in the soils treated at the low fertilizer level. These results indicate that an understanding of nutrient effects at a specific site is essential for successful bioremediation.Bioremediation is being used or proposed as a treatment option at many hydrocarbon-contaminated sites. One such site is a former bulk-fuel storage facility near Barrow, AK, where contamination persists after approximately 380 m3 of JP-5 was spilled in 1970. The soil at the site is primarily coarse sand with low organic carbon (<1%) and low moisture (1-3%) contents. We examined the effects of nutrient additions on microorganisms in contaminated soil from this site in laboratory microcosms and in mesocosms incubated for 6 weeks in the field. Nitrogen was the major limiting nutrient in this system, but microbial populations and activity were maximally enhanced by additions of both nitrogen and phosphorus

  19. Irrigation of three wetland species and a hyperaccumlating fern with arsenic-laden solutions: observations of growth, arsenic uptake, nutrient status, and chlorophyll content.

    PubMed

    Rofkar, Jordan R; Dwyer, Daryl F

    2013-01-01

    Engineered wetlands can be an integral part of a treatment strategy for remediating arsenic-contaminated wastewater, wherein, As is removed by adsorption to soil particles, chemical transformation, precipitation, or accumulation by plants. The remediation process could be optimized by choosing plant species that take up As throughout the seasonal growing period. This report details experiments that utilize wetland plant species native to Ohio (Carex stricta, Pycnanthemum virginianum, and Spartina pectinata) that exhibit seasonally related maximal growth rates, plus one hyperaccumulating fern (Pteris vittata) that was used to compare arsenic tolerance. All plants were irrigated with control or As-laden nutrient solutions (either 0, 1.5, or 25 mg As L(-1)) for 52 d. Biomass, nutrient content, and chlorophyll content were compared between plants treated and control plants (n = 5). At the higher concentration of arsenic (25 mg L(-1)), plant biomass, leaf area, and total chlorophyll were all lower than values in control plants. A tolerance index, based on total plant biomass at the end of the experiment, indicated C. stricta (0.99) and S. pectinata (0.84) were more tolerant than the other plant species when irrigated with 1.5 mg As L(-1). These plant species can be considered as candidates for engineered wetlands.

  20. Exploring equity in uptake of the NHS Health Check and a nested physical activity intervention trial

    PubMed Central

    Attwood, S.; Morton, K.; Sutton, S.

    2016-01-01

    Background Socio-demographic factors characterizing disadvantage may influence uptake of preventative health interventions such as the NHS Health Check and research trials informing their content. Methods A cross-sectional study examining socio-demographic characteristics of participants and non-participants to the NHS Health Check and a nested trial of very brief physical activity interventions within this context. Age, gender, Index of Multiple Deprivation (IMD) and ethnicity were extracted from patient records of four General Practices (GP) in England. Results In multivariate analyses controlling for GP surgery, the odds of participation in the Health Check were higher for older patients (OR 1.05, 95% CI 1.04–1.07) and lower from areas of greater deprivation (IMD Quintiles 4 versus 1, OR 0.37, 95% CI 0.18–0.76, 5 versus 1 OR 0.42, 95% CI 0.20–0.88). Older patients were more likely to participate in the physical activity trial (OR 1.04, 95% CI 1.02–1.06). Conclusions Younger patients and those living in areas of greater deprivation may be at risk of non-participation in the NHS Health Check, while younger age also predicted non-participation in a nested research trial. The role that GP-surgery-specific factors play in influencing participation across different socio-demographic groups requires further exploration. PMID:26036701

  1. Oxygen uptake and energy expenditure for children during rock climbing activity.

    PubMed

    Watts, Phillip Baxter; Ostrowski, Megan L

    2014-02-01

    The purpose of this study was to measure oxygen uptake and energy expenditure in children during rock climbing activity. 29 children (age = 10.9 ± 1.7 yr) participated in the study. A commercially available rock climbing structure with ample features for submaximal effort climbing provided continuous terrain. Participants were instructed to climb at a comfortable pace. Following an initial 5-min rest, each child climbed one sustained 5-min bout followed by 5-min sitting recovery for a total of 10 min (SUS). This was immediately followed by five 1-min climbing + 1-min recovery intervals for a second total of 10 min (INT). Expired air was analyzed continuously. Energy expenditure (EE) was determined via the Weir method for 10-s intervals throughout the full protocol. The total energy expenditure in kilocalories during the 10-min SUS period was 34.3 ± 11.3 kcal. Energy expenditure during the 10-min INT period averaged 39.3 ± 13.1 kcal and was significantly higher than during SUS (p < .05). The mean total EE for SUS + INT was 73.7 ± 24.2 kcal. EE was correlated with body mass; r = .86. The rock climbing tasks employed in this study produced EE levels similar to what have been reported in children for stair climbing, sports/games activities, and easy jogging.

  2. Nutrient elements of commercial tea from Nigeria by an instrumental neutron activation analysis technique.

    PubMed

    Jona, S A; Williams, I S

    2000-08-30

    A prototype miniature neutron source reactor (MNSR) with a thermal neutron flux of 3.0 x 10(11) n cm(-2) s(-1) has been used to determine the concentrations of some nutrient elements leading to short-lived activation products in commercial tea leaf samples from Nigeria. A total of eight elements Al, Ca, Cl, Cu, K, Mg, Mn and Na, that can be routinely used for quality control purposes, were analyzed in this study. Two biological reference materials, tomato leaves (NIST-1573) and citrus leaves (NIST-1572) were used as the standard and quality control materials, respectively. The analytical results show that the average concentrations of Al, Ca, Cl, Cu, K, Mg, Mn and Na in Nigerian tea are slightly higher when compared with a Chinese herbal tea analyzed in this study. The concentration ratios of K/Ca were found to be high in all the samples analyzed suggesting cultivation in potash-rich soils.

  3. The effect of antigen encapsulation in chitosan particles on uptake, activation and presentation by antigen presenting cells.

    PubMed

    Koppolu, Bhanuprasanth; Zaharoff, David A

    2013-03-01

    Particle-based vaccine delivery systems are under exploration to enhance antigen-specific immunity against safe but poorly immunogenic polypeptide antigens. Chitosan is a promising biomaterial for antigen encapsulation and delivery due to its ability to form nano- and microparticles in mild aqueous conditions thus preserving the antigenicity of loaded polypeptides. In this study, the influence of chitosan encapsulation on antigen uptake, activation and presentation by antigen presenting cells (APCs) is explored. Fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) and ovalbumin (OVA) were used as model protein antigens and encapsulated in chitosan particles via precipitation-coacervation at loading efficiencies >89%. Formulation conditions were manipulated to create antigen-encapsulated chitosan particles (AgCPs) with discrete nominal sizes (300 nm, 1 μm, and 3 μm). Uptake of AgCPs by dendritic cells and macrophages was found to be dependent on particle size, antigen concentration and exposure time. Flow cytometry analysis revealed that uptake of AgCPs enhanced upregulation of surface activation markers on APCs and increased the release of pro-inflammatory cytokines. Lastly, antigen-specific T cells exhibited higher proliferative responses when stimulated with APCs activated with AgCPs versus soluble antigen. These data suggest that encapsulation of antigens in chitosan particles enhances uptake, activation and presentation by APCs.

  4. Effects of Body Mass Index on Task-Related Oxygen Uptake and Dyspnea during Activities of Daily Life in COPD

    PubMed Central

    Vaes, Anouk W.; Franssen, Frits M. E.; Meijer, Kenneth; Cuijpers, Martijn W. J.; Wouters, Emiel F. M.; Rutten, Erica P. A.; Spruit, Martijn A.

    2012-01-01

    Background Patients with COPD use a higher proportion of their peak aerobic capacity during the performance of domestic activities of daily life (ADLs) compared to healthy peers, accompanied by a higher degree of task-related symptoms. To date, the influence of body mass index (BMI) on the task-related metabolic demands remains unknown in patients with COPD. Therefore, the aim of our study was to determine the effects of BMI on metabolic load during the performance of 5 consecutive domestic ADLs in patients with COPD. Methodology Ninety-four COPD patients and 20 healhty peers performed 5 consecutive, self-paced domestic ADLs putting on socks, shoes and vest; folding 8 towels; putting away groceries; washing up 4 dishes, cups and saucers; and sweeping the floor for 4 min. Task-related oxygen uptake and ventilation were assessed using a mobile oxycon, while Borg scores were used to assess task-related dyspnea and fatigue. Principal Findings 1. Relative task-related oxygen uptake after the performance of domestic ADLs was increased in patients with COPD compared to healthy elderly, whereas absolute oxygen uptake is similar between groups; 2. Relative oxygen uptake and oxygen uptake per kilogram fat-free mass were comparable between BMI groups; and 3. Borg symptom scores for dyspnea en fatigue were comparable between BMI groups. Conclusion Patients with COPD in different BMI groups perform self-paced domestic ADLs at the same relative metabolic load, accompanied by comparable Borg symptom scores for dyspnea and fatigue. PMID:22815922

  5. Intracellular Distribution and Nuclear Activity of Antisense Oligonucleotides After Unassisted Uptake in Myoblasts and Differentiated Myotubes In Vitro.

    PubMed

    González-Barriga, Anchel; Nillessen, Bram; Kranzen, Julia; van Kessel, Ingeborg D G; Croes, Huib J E; Aguilera, Begoña; de Visser, Peter C; Datson, Nicole A; Mulders, Susan A M; van Deutekom, Judith C T; Wieringa, Bé; Wansink, Derick G

    2017-04-04

    Clinical efficacy of antisense oligonucleotides (AONs) for the treatment of neuromuscular disorders depends on efficient cellular uptake and proper intracellular routing to the target. Selection of AONs with highest in vitro efficiencies is usually based on chemical or physical methods for forced cellular delivery. Since these methods largely bypass existing natural mechanisms for membrane passage and intracellular trafficking, spontaneous uptake and distribution of AONs in cells are still poorly understood. Here, we report on the unassisted uptake of naked AONs, so-called gymnosis, in muscle cells in culture. We found that gymnosis works similarly well for proliferating myoblasts as for terminally differentiated myotubes. Cell biological analyses combined with microscopy imaging showed that a phosphorothioate backbone promotes efficient gymnosis, that uptake is clathrin mediated and mainly results in endosomal-lysosomal accumulation. Nuclear localization occurred at a low level, but the gymnotically delivered AONs effectively modulated the expression of their nuclear RNA targets. Chloroquine treatment after gymnotic delivery helped increase nuclear AON levels. In sum, we demonstrate that gymnosis is feasible in proliferating and non-proliferating muscle cells and we confirm the relevance of AON chemistry for uptake and intracellular trafficking with this method, which provides a useful means for bio-activity screening of AONs in vitro.

  6. The argon-induced decline in nitrogenase activity commences before the beginning of a decline in nodule oxygen uptake.

    PubMed

    Fischinger, Stephanie A; Schulze, Joachim

    2010-09-01

    Replacement of N(2) by argon in the air around nodules directs nitrogenase electron flow in its total onto H(+) resulting in increased nodule H(2) evolution (total nitrogenase activity (TNA)). However, argon application induces a so-called argon-induced decline in nitrogenase activity (Ar-ID) connected with decreased nodule oxygen permeability. Consequently, TNA measurements tend to underestimate total nitrogenase activity. It is unclear whether the decline in oxygen diffusion into nodules induces the Ar-ID, or whether a decline in nitrogenase activity is followed by lower nodule O(2) uptake. The objective of the present work was to examine the time sequence of the decline in nodule H(2) evolution and O(2) uptake after argon application. In addition, the reliability of TNA values, taken as quickly as possible after the switch to Ar/O(2), was tested through comparative measurement of (15)N(2) uptake of the same plants. Short-term TNA measurements in an optimized gas exchange measurement system yielded reliable results, verified by parallel determination of (15)N(2) uptake. A five min application of Ar/O(2) was without effect on the subsequent H(2) evolution in ambient air. A parallel experiment on control plants revealed that a decrease in nodule oxygen uptake began several minutes after the onset of the decline in H(2) evolution. We conclude that the primary effect of the replacement of N(2) by argon differs from oxygen diffusion control. A gas exchange system allowing an immediate taking of TNA yields reliable results and does not disturb nodule activity. Gas exchange measurements provide a powerful tool for studying nodule physiology and should be combined with material from molecular studies.

  7. Interfacing carbon nanotubes (CNT) with plants: enhancement of growth, water and ionic nutrient uptake in maize ( Zea mays) and implications for nanoagriculture

    NASA Astrophysics Data System (ADS)

    Tiwari, D. K.; Dasgupta-Schubert, N.; Villaseñor Cendejas, L. M.; Villegas, J.; Carreto Montoya, L.; Borjas García, S. E.

    2014-06-01

    The application of nano-biotechnology to crop-science/agriculture (`nanoagriculture') is a recent development. While carbon nanotubes (CNTs) have been shown to dramatically improve germination of some comestible plants, deficiencies in consistency of behavior and reproducibility arise, partially from the variability of the CNTs used. In this work, factory-synthesized multi-walled-CNTs (MWCNTs) of quality-controlled specifications were seen to enhance the germinative growth of maize seedlings at low concentrations but depress it at higher concentrations. Growth enhancement principally arose through improved water delivery by the MWCNT. Polarized EDXRF spectrometry showed that MWCNTs affect mineral nutrient supply to the seedling through the action of the mutually opposing forces of inflow with water and retention in the medium by the ion-CNT transient-dipole interaction. The effect varied with ion type and MWCNT concentration. The differences of the Fe tissue concentrations when relatively high equimolar Fe2+ or Fe3+ was introduced, implied that the ion-CNT interaction might induce redox changes to the ion. The tissue Ca2+ concentration manifested as the antipode of the Fe2+ concentration indicating a possible cationic exchange in the cell wall matrix. SEM images showed that MWCNTs perforated the black-layer seed-coat that could explain the enhanced water delivery. The absence of perforations with the introduction of FeCl2/FeCl3 reinforces the idea of the modification of MWCNT functionality by the ion-CNT interaction. Overall, in normal media, low dose MWCNTs were seen to be beneficial, improving water absorption, plant biomass and the concentrations of the essential Ca, Fe nutrients, opening a potential for possible future commercial agricultural applications.

  8. IL-7 promotes Glut1 trafficking and glucose uptake via STAT5-mediated activation of Akt to support T-cell survival.

    PubMed

    Wofford, Jessica A; Wieman, Heather L; Jacobs, Sarah R; Zhao, Yuxing; Rathmell, Jeffrey C

    2008-02-15

    Lymphocyte homeostasis requires coordination of metabolic processes with cellular energetic and biosynthetic demands but mechanisms that regulate T-cell metabolism are uncertain. We show that interleukin-7 (IL-7) is a key regulator of glucose uptake in T lymphocytes. To determine how IL-7 affects glucose uptake, we analyzed IL-7 signaling mechanisms and regulation of the glucose transporter, Glut1. The IL-7 receptor (IL-7R) stimulated glucose uptake and cell-surface localization of Glut1 in a manner that required IL-7R Y449, which promoted rapid signal transducer and activator of transcription 5 (STAT5) activation and a delayed yet sustained activation of Akt. Each pathway was necessary for IL-7 to promote glucose uptake, as Akt1(-/-) T cells or PI3-kinase inhibition and RNAi of STAT5 led to defective glucose uptake in response to IL-7. STAT5 and Akt acted in a linear pathway, with STAT5-mediated transcription leading to Akt activation, which was necessary for STAT5 and IL-7 to promote glucose uptake and prevent cell death. Importantly, IL-7 required glucose uptake to promote cell survival. These data demonstrate that IL-7 promotes glucose uptake via a novel signaling mechanism in which STAT5 transcriptional activity promotes Akt activation to regulate Glut1 trafficking and glucose uptake that is critical for IL-7 to prevent T-cell death and maintain homeostasis.

  9. Forms of selenium affect its transport, uptake and glutathione peroxidase activity in the Caco-2 cell model.

    PubMed

    Wang, Yanbo; Fu, Linglin

    2012-10-01

    The experiment was designed to investigate the effect of selenium (Se) chemical forms (sodium selenite, selenium nanoparticle [nano-Se] and selenomethionine) on the transport, uptake and glutathione peroxidase (GSH-Px) activity in the Caco-2 cell model. The transport and uptake of different forms of Se (0.1 μmol l(-1)) across the Caco-2 cell monolayer were carried out in two directions (apical [AP] to basolateral [BL] and BL to AP) for 2 h, respectively, and the apparent permeability coefficient (P(app)), transport efficiency and uptake efficiency were all calculated. In the present study, the transport and uptake of three forms of Se were time-dependent both in AP to BL and BL to AP directions. By the end of 2 h, the transport efficiencies of selenomethionine and nano-Se were higher than that of sodium selenite (P<0.05). The highest uptake efficiency (P<0.05) was observed in cells treated with nano-Se and significant difference (P<0.05) was also observed between the cells incubated with sodium selenite and selenomethionine. As for the P(app), sodium selenite (P<0.05) had the lowest values compared with that of selenomethionine and nano-Se, in both AP-BL and BL-AP. However, no significant differences were observed in GSH-Px activities. These results indicated that the efficiency of Se in the Caco-2 cells varied with its chemical forms, which might be associated with the differences in Se transport and uptake.

  10. IL-15 Activates the Jak3/STAT3 Signaling Pathway to Mediate Glucose Uptake in Skeletal Muscle Cells.

    PubMed

    Krolopp, James E; Thornton, Shantaé M; Abbott, Marcia J

    2016-01-01

    Myokines are specialized cytokines that are secreted from skeletal muscle (SKM) in response to metabolic stimuli, such as exercise. Interleukin-15 (IL-15) is a myokine with potential to reduce obesity and increase lean mass through induction of metabolic processes. It has been previously shown that IL-15 acts to increase glucose uptake in SKM cells. However, the downstream signals orchestrating the link between IL-15 signaling and glucose uptake have not been fully explored. Here we employed the mouse SKM C2C12 cell line to examine potential downstream targets of IL-15-induced alterations in glucose uptake. Following differentiation, C2C12 cells were treated overnight with 100 ng/ml of IL-15. Activation of factors associated with glucose metabolism (Akt and AMPK) and known downstream targets of IL-15 (Jak1, Jak3, STAT3, and STAT5) were assessed with IL-15 stimulation. IL-15 stimulated glucose uptake and GLUT4 translocation to the plasma membrane. IL-15 treatment had no effect on phospho-Akt, phospho-Akt substrates, phospho-AMPK, phospho-Jak1, or phospho-STAT5. However, with IL-15, phospho-Jak3 and phospho-STAT3 levels were increased along with increased interaction of Jak3 and STAT3. Additionally, IL-15 induced a translocation of phospho-STAT3 from the cytoplasm to the nucleus. We have evidence that a mediator of glucose uptake, HIF1α, expression was dependent on IL-15 induced STAT3 activation. Finally, upon inhibition of STAT3 the positive effects of IL-15 on glucose uptake and GLUT4 translocation were abolished. Taken together, we provide evidence for a novel signaling pathway for IL-15 acting through Jak3/STAT3 to regulate glucose metabolism.

  11. IL-15 Activates the Jak3/STAT3 Signaling Pathway to Mediate Glucose Uptake in Skeletal Muscle Cells

    PubMed Central

    Krolopp, James E.; Thornton, Shantaé M.; Abbott, Marcia J.

    2016-01-01

    Myokines are specialized cytokines that are secreted from skeletal muscle (SKM) in response to metabolic stimuli, such as exercise. Interleukin-15 (IL-15) is a myokine with potential to reduce obesity and increase lean mass through induction of metabolic processes. It has been previously shown that IL-15 acts to increase glucose uptake in SKM cells. However, the downstream signals orchestrating the link between IL-15 signaling and glucose uptake have not been fully explored. Here we employed the mouse SKM C2C12 cell line to examine potential downstream targets of IL-15-induced alterations in glucose uptake. Following differentiation, C2C12 cells were treated overnight with 100 ng/ml of IL-15. Activation of factors associated with glucose metabolism (Akt and AMPK) and known downstream targets of IL-15 (Jak1, Jak3, STAT3, and STAT5) were assessed with IL-15 stimulation. IL-15 stimulated glucose uptake and GLUT4 translocation to the plasma membrane. IL-15 treatment had no effect on phospho-Akt, phospho-Akt substrates, phospho-AMPK, phospho-Jak1, or phospho-STAT5. However, with IL-15, phospho-Jak3 and phospho-STAT3 levels were increased along with increased interaction of Jak3 and STAT3. Additionally, IL-15 induced a translocation of phospho-STAT3 from the cytoplasm to the nucleus. We have evidence that a mediator of glucose uptake, HIF1α, expression was dependent on IL-15 induced STAT3 activation. Finally, upon inhibition of STAT3 the positive effects of IL-15 on glucose uptake and GLUT4 translocation were abolished. Taken together, we provide evidence for a novel signaling pathway for IL-15 acting through Jak3/STAT3 to regulate glucose metabolism. PMID:28066259

  12. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon

    USGS Publications Warehouse

    McLeod, Pamela B.; Luoma, S.N.; Luthy, R.G.

    2008-01-01

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms. ?? 2008 American Chemical Society.

  13. Biodynamic modeling of PCB uptake by Macoma balthica and Corbicula fluminea from sediment amended with activated carbon.

    PubMed

    McLeod, Pamela B; Luoma, Samuel N; Luthy, Richard G

    2008-01-15

    Activated carbon amendment was assessed in the laboratory as a remediation strategy for freshwater sediment contaminated with polychlorinated biphenyls (PCBs) from the Grasse River (near Massena, NY). Three end points were evaluated: aqueous equilibrium PCB concentration, uptake into semipermeable membrane devices (SPMDs), and 28-day bioaccumulation in the clam Corbicula fluminea. PCB uptake by water, SPMDs, and clams followed similar trends, with reductions increasing as a function of carbon dose. Average percent reductions in clam tissue PCBs were 67, 86, and 95% for activated carbon doses of 0.7, 1.3, and 2.5% dry wt, respectively. A biodynamic model that incorporates sediment geochemistry and dietary and aqueous uptake routes was found to agree well with observed uptake by C. fluminea in our laboratory test systems. Results from this study were compared to 28-day bioaccumulation experiments involving PCB-contaminated sediment from Hunters Point Naval Shipyard (San Francisco Bay, CA) and the clam Macoma balthica. Due to differences in feeding strategy, M. balthica deposit-feeds whereas C. fluminea filter-feeds, the relative importance of the aqueous uptake route is predicted to be much higher for C. fluminea than for M. balthica. Whereas M. balthica takes up approximately 90% of its body burden through sediment ingestion, C. fluminea only accumulates approximately 45% via this route. In both cases, results strongly suggest that it is the mass transfer of PCBs from native sediment to added carbon particles, not merely reductions in aqueous PCB concentrations, that effectively reduces PCB bioavailability and uptake by sediment-dwelling organisms.

  14. Role of the scavenger receptor in the uptake of methylamine-activated alpha 2-macroglobulin by rat liver.

    PubMed Central

    van Dijk, M C; Boers, W; Linthorst, C; van Berkel, T J

    1992-01-01

    Alpha 2-Macroglobulin (alpha 2M) requires activation by small nucleophiles (e.g. methylamine; giving alpha 2M-Me) or proteolytic enzymes (e.g. trypsin; giving alpha 2M-Tr) in order to be rapidly removed from the circulation by the liver. Separation of rat liver cells into parenchymal, endothelial and Kupffer cells at 10 min after injection indicates that liver uptake of alpha 2M-Me is shared between parenchymal and endothelial cells, with relative contributions of 51.3% and 48.3% respectively of total liver-associated radioactivity. In contrast, alpha 2M-Tr is almost exclusively taken up by the parenchymal cells (90.1% of liver-associated radioactivity). A preinjection of 5 mg of poly(inosinic acid) decreased liver uptake of alpha 2M-Me to 39.9% of the control value, while it had no effect on liver uptake of alpha 2M-Tr. It appears that poly(inosinic acid) specifically reduces the uptake of alpha 2M-Me in vivo by endothelial cells, leaving uptake by parenchymal cells unaffected. In vitro studies with isolated liver cells indicate that the association of alpha 2M-Me with endothelial cells is 21-fold higher per mg of cell protein than with parenchymal cells. The capacity of endothelial cells to degrade alpha 2M-Me appears to be 46 times higher than that of parenchymal cells. Competition studies show that poly(inosinic acid) or acetylated low-density lipoprotein effectively competes with the association of alpha 2M-Me with endothelial and Kupffer cells, but association with parenchymal cells is unaffected. It is suggested that activation of alpha 2M by methylamine induces a charge distribution on the protein which triggers specific uptake by the scavenger receptor on endothelial cells. It is concluded that the uptake of alpha 2M-Me by the scavenger receptor might function as an additional system for the uptake of activated alpha 2M. Images Fig. 11. PMID:1280102

  15. Impacts of membrane flux enhancers on activated sludge respiration and nutrient removal in MBRs.

    PubMed

    Iversen, Vera; Koseoglu, Hasan; Yigit, Nevzat O; Drews, Anja; Kitis, Mehmet; Lesjean, Boris; Kraume, Matthias

    2009-02-01

    This paper presents the findings of experimental investigations regarding the influence of 13 different flux enhancing chemicals (FeCl3, polyaluminium chloride, 2 chitosans, 5 synthetic polymers, 2 starches and 2 activated carbons) on respirometric characteristics and nitrification/denitrification performance of membrane bioreactor (MBR) mixed liquor. Flux enhancing chemicals are a promising method to reduce the detrimental effects of fouling phenomena via the modification of mixed liquor characteristics. However, potentially inhibiting effects of these chemicals on mixed liquor biological activity triggered the biokinetic studies (in jar tests) conducted in this work. The tested polyaluminium chloride (PACl) strongly impacted on nitrification (-16%) and denitrification rate (-43%). The biodegradable nature of chitosan was striking in endogenous and exogenous tests. Considering the relatively high costs of this chemical, an application for wastewater treatment does thus not seem to be advisable. Also, addition of one of the tested activated carbons strongly impacted on the oxygen uptake rate (-28%), nitrification (-90%) and denitrification rate (-43%), due to a decrease of pH. Results show that the changes in kLa values were mostly not significant, however, a decrease of 13% in oxygen transfer was found for sludge treated with PACl.

  16. Estrogen effects on thyroid iodide uptake and thyroperoxidase activity in normal and ovariectomized rats.

    PubMed

    Lima, Lívia P; Barros, Inês A; Lisbôa, Patrícia C; Araújo, Renata L; Silva, Alba C M; Rosenthal, Doris; Ferreira, Andrea C F; Carvalho, Denise P

    2006-08-01

    Sex steroids interfere with the pituitary-thyroid axis function, although the reports have been controversial and no conclusive data is available. Some previous reports indicate that estradiol might also regulate thyroid function through a direct action on the thyrocytes. In this report, we examined the effects of low and high doses of estradiol administered to control and ovariectomized adult female rats and to pre-pubertal females. We demonstrate that estradiol administration to both intact adult and pre-pubertal females causes a significant increase in the relative thyroid weight. Serum T3 is significantly decreased in ovariectomized rats, and is normalized by estrogen replacement. Neither doses of estrogen produced a significant change in serum TSH and total T4 in ovariectomized, adult intact and pre-pubertal rats. The highest, supraphysiological, estradiol dose produced a significant increase in thyroid iodide uptake in ovariectomized and in pre-pubertal rats, but not in control adult females. Thyroperoxidase activity was significantly higher in intact adult rats treated with both estradiol doses and in ovariectomized rats treated with the highest estradiol dose. Since serum TSH levels were not significantly changed, we suggest a direct action of estradiol on the thyroid gland, which depends on the age and on the previous gonad status of the animal.

  17. Validation of theoretical framework explaining active solute uptake in dynamically loaded porous media.

    PubMed

    Albro, Michael B; Li, Roland; Banerjee, Rajan E; Hung, Clark T; Ateshian, Gerard A

    2010-08-26

    Solute transport in biological tissues is a fundamental process necessary for cell metabolism. In connective soft tissues, such as articular cartilage, cells are embedded within a dense extracellular matrix that hinders the transport of solutes. However, according to a recent theoretical study (Mauck et al., 2003, J. Biomech. Eng. 125, 602-614), the convective motion of a dynamically loaded porous solid matrix can also impart momentum to solutes, pumping them into the tissue and giving rise to concentrations which exceed those achived under passive diffusion alone. In this study, the theoretical predictions of this model are verified against experimental measurements. The mechanical and transport properties of an agarose-dextran model system were characterized from independent measurements and substituted into the theory to predict solute uptake or desorption under dynamic mechanical loading for various agarose concentrations and dextran molecular weights, as well as different boundary and initial conditions. In every tested case, agreement was observed between experiments and theoretical predictions as assessed by coefficients of determination ranging from R(2)=0.61 to 0.95. These results provide strong support for the hypothesis that dynamic loading of a deformable porous tissue can produce active transport of solutes via a pumping mechanisms mediated by momentum exchange between the solute and solid matrix.

  18. Mechanistic insights into metal ion activation and operator recognition by the ferric uptake regulator

    NASA Astrophysics Data System (ADS)

    Deng, Zengqin; Wang, Qing; Liu, Zhao; Zhang, Manfeng; Machado, Ana Carolina Dantas; Chiu, Tsu-Pei; Feng, Chong; Zhang, Qi; Yu, Lin; Qi, Lei; Zheng, Jiangge; Wang, Xu; Huo, Xinmei; Qi, Xiaoxuan; Li, Xiaorong; Wu, Wei; Rohs, Remo; Li, Ying; Chen, Zhongzhou

    2015-07-01

    Ferric uptake regulator (Fur) plays a key role in the iron homeostasis of prokaryotes, such as bacterial pathogens, but the molecular mechanisms and structural basis of Fur-DNA binding remain incompletely understood. Here, we report high-resolution structures of Magnetospirillum gryphiswaldense MSR-1 Fur in four different states: apo-Fur, holo-Fur, the Fur-feoAB1 operator complex and the Fur-Pseudomonas aeruginosa Fur box complex. Apo-Fur is a transition metal ion-independent dimer whose binding induces profound conformational changes and confers DNA-binding ability. Structural characterization, mutagenesis, biochemistry and in vivo data reveal that Fur recognizes DNA by using a combination of base readout through direct contacts in the major groove and shape readout through recognition of the minor-groove electrostatic potential by lysine. The resulting conformational plasticity enables Fur binding to diverse substrates. Our results provide insights into metal ion activation and substrate recognition by Fur that suggest pathways to engineer magnetotactic bacteria and antipathogenic drugs.

  19. Iron uptake and increased intracellular enzyme activity follow host lactoferrin binding by Trichomonas vaginalis receptors

    SciTech Connect

    Peterson, K.M.; Alderete, J.F.

    1984-08-01

    Lactoferrin acquisition and iron uptake by pathogenic Trichomonas vaginalis was examined. Saturation binding kinetics were obtained for trichomonads using increasing amounts of radioiodinated lactoferrin, while no significant binding by transferrin under similar conditions was achieved. Only unlabeled lactoferrin successfully and stoichiometrically competed with 125I-labeled lactoferrin binding. Time course studies showed maximal lactoferrin binding by 30 min at 37 degrees C. Data suggest no internalization of bound lactoferrin. The accumulation of radioactivity in supernatants after incubation of T. vaginalis with 125I-labeled lactoferrin and washing in PBS suggested the presence of low affinity sites for this host macromolecule. Scatchard analysis indicated the presence of 90,000 receptors per trichomonad with an apparent Kd of 1.0 microM. Two trichomonad lactoferrin binding proteins were identified by affinity chromatography and immunoprecipitation of receptor-ligand complexes. A 30-fold accumulation of iron was achieved using 59Fe-lactoferrin when compared to the steady state concentration of bound lactoferrin. The activity of pyruvate/ferrodoxin oxidoreductase, an enzyme involved in trichomonal energy metabolism, increased more than sixfold following exposure of the parasites to lactoferrin, demonstrating a biologic response to the receptor-mediated binding of lactoferrin. These data suggest that T. vaginalis possesses specific receptors for biologically relevant host proteins and that these receptors contribute to the metabolic processes of the parasites.

  20. Copper Uptake in Mammary Epithelial Cells Activates Cyclins and Triggers Antioxidant Response.

    PubMed

    dos Santos, Nathália Villa; Matias, Andreza Cândido; Higa, Guilherme Shigueto Vilar; Kihara, Alexandre Hiroaki; Cerchiaro, Giselle

    2015-01-01

    The toxicologic effects of copper (Cu) on tumor cells have been studied during the past decades, and it is suggested that Cu ion may trigger antiproliferative effects in vitro. However, in normal cells the toxicologic effects of high exposures of free Cu are not well understood. In this work, Cu uptake, the expression of genes associated with cell cycle regulation, and the levels of ROS production and related oxidative processes were evaluated in Cu-treated mammary epithelial MCF10A nontumoral cells. We have shown that the Cu additive is associated with the activation of cyclin D1 and cyclin B1, as well as cyclin-dependent kinase 2 (CDK2). These nontumor cells respond to Cu-induced changes in the oxidative balance by increase of the levels of reduced intracellular glutathione (GSH), decrease of reactive oxygen species (ROS) generation, and accumulation during progression of the cell cycle, thus preventing the cell abnormal proliferation or death. Taken together, our findings revealed an effect that contributes to prevent a possible damage of normal cells exposed to chemotherapeutic effects of drugs containing the Cu ion.

  1. Validation of theoretical framework explaining active solute uptake in dynamically loaded porous media

    PubMed Central

    Albro, Michael B.; Li, Roland; Banerjee, Rajan E.; Hung, Clark T.; Ateshian, Gerard A.

    2010-01-01

    Solute transport in biological tissues is a fundamental process necessary for cell metabolism. In connective soft tissues, such as articular cartilage, cells are embedded within a dense extracellular matrix that hinders the transport of solutes. However, according to a recent theoretical study (Mauck et al., 2003, J. Biomech. Eng. 125, 602–614), the convective motion of a dynamically loaded porous solid matrix can also impart momentum to solutes, pumping them into the tissue and giving rise to concentrations which exceed those achived under passive diffusion alone. In this study, the theoretical predictions of this model are verified against experimental measurements. The mechanical and transport properties of an agarose–dextran model system were characterized from independent measurements and substituted into the theory to predict solute uptake or desorption under dynamic mechanical loading for various agarose concentrations and dextran molecular weights, as well as different boundary and initial conditions. In every tested case, agreement was observed between experiments and theoretical predictions as assessed by coefficients of determination ranging from R2=0.61 to 0.95. These results provide strong support for the hypothesis that dynamic loading of a deformable porous tissue can produce active transport of solutes via a pumping mechanisms mediated by momentum exchange between the solute and solid matrix. PMID:20553797

  2. Superposition of Individual Activities: Urea-Mediated Suppression of Nitrate Uptake in the Dinoflagellate Prorocentrum minimum Revealed at the Population and Single-Cell Levels

    PubMed Central

    Matantseva, Olga; Skarlato, Sergei; Vogts, Angela; Pozdnyakov, Ilya; Liskow, Iris; Schubert, Hendrik; Voss, Maren

    2016-01-01

    Dinoflagellates readily use diverse inorganic and organic compounds as nitrogen sources, which is advantageous in eutrophied coastal areas exposed to high loads of anthropogenic nutrients, e.g., urea, one of the most abundant organic nitrogen substrates in seawater. Cell-to-cell variability in nutritional physiology can further enhance the diversity of metabolic strategies among dinoflagellates of the same species, but it has not been studied in free-living microalgae. We applied stable isotope tracers, isotope ratio mass spectrometry and nanoscale secondary ion mass spectrometry (NanoSIMS) to investigate the response of cultured nitrate-acclimated dinoflagellates Prorocentrum minimum to a sudden input of urea and the effect of urea on the concurrent nitrate uptake at the population and single-cell levels. We demonstrate that inputs of urea lead to suppression of nitrate uptake by P. minimum, and urea uptake exceeds the concurrent uptake of nitrate. Individual dinoflagellate cells within a population display significant heterogeneity in the rates of nutrient uptake and extent of the urea-mediated inhibition of the nitrate uptake, thus forming several groups characterized by different modes of nutrition. We conclude that urea originating from sporadic sources is rapidly utilized by dinoflagellates and can be used in biosynthesis or stored intracellularly depending on the nutrient status; therefore, sudden urea inputs can represent one of the factors triggering or supporting harmful algal blooms. Significant physiological heterogeneity revealed at the single-cell level is likely to play a role in alleviation of intra-population competition for resources and can affect the dynamics of phytoplankton populations and their maintenance in natural environments. PMID:27610101

  3. Contraction inhibits insulin-stimulated insulin receptor substrate-1/2-associated phosphoinositide 3-kinase activity, but not protein kinase B activation or glucose uptake, in rat muscle.

    PubMed Central

    Whitehead, J P; Soos, M A; Aslesen, R; O'rahilly, S; Jensen, J

    2000-01-01

    The initial stages of insulin-stimulated glucose uptake are thought to involve tyrosine phosphorylation of insulin receptor substrates (IRSs), which recruit and activate phosphoinositide 3-kinase (PI 3-kinase), leading to the activation of protein kinase B (PKB) and other downstream effectors. In contrast, contraction stimulates glucose uptake via a PI 3-kinase-independent mechanism. The combined effects of insulin and contraction on glucose uptake are additive. However, it has been reported that contraction causes a decrease in insulin-stimulated IRS-1-associated PI 3-kinase activity. To investigate this paradox, we have examined the effects of contraction on insulin-stimulated glucose uptake and proximal insulin-signalling events in isolated rat epitrochlearis muscle. Stimulation by insulin or contraction produced a 3-fold increase in glucose uptake, with the effects of simultaneous treatment by insulin and contraction being additive. Wortmannin completely blocked the additive effect of insulin in contracting skeletal muscle, indicating that this is a PI 3-kinase-dependent effect. Insulin-stimulated recruitment of PI 3-kinase to IRS-1 was unaffected by contraction; however, insulin produced no discernible increase in PI 3-kinase activity in IRS-1 or IRS-2 immunocomplexes in contracting skeletal muscle. Consistent with this, contraction inhibited insulin-stimulated p70(S6K) activation. In contrast, insulin-stimulated activation of PKB was unaffected by contraction. Thus, in contracting skeletal muscle, insulin stimulates glucose uptake and activates PKB, but not p70(S6K), by a PI 3-kinase-dependent mechanism that is independent of changes in IRS-1- and IRS-2-associated PI 3-kinase activity. PMID:10903138

  4. Critical zinc[sup +2] activities for sour orange determined with chelator-buffered nutrient solutions

    SciTech Connect

    Swietlik, D.; Zhang, L. )

    1994-07-01

    Chelator-buffered nutrient solutions were used to study the effect of different levels of Zn activity in the rhizosphere on growth and nutritive responses of various tissues of sour orange seedlings. The seedlings were grown for 3 months in a growth chamber in a hydroponic culture containing from 5 to 69 [mu]m and 5 to 101 [mu]m total Zn in Expts. 1 and 2, respectively. Zn[sup +2] activities were calculated with a computerized chemical equilibrium model, and buffered by inclusion of a chelator, diethylenetriamine pentaacetate (DTPA), at 74 and 44 [mu]m in excess of the sum of Fe, Mn, Zn, Cu, Ni, and Co in Expts. 1 and 2, respectively. The use of DTPA-buffered solutions proved successful in imposing varying degrees of Zn deficiency. The deficiency was confirmed by leaf symptomatology, leaf chemical analyses, i.e., <16 mg[center dot]kg[sup [minus]1] Zn, and responses to foliar sprays and application of Zn to the roots. Growth parameters varied in their sensitivity to Zn deficiency, i.e., root dry weight < leaf number and white root growth < stem dry weight < leaf dry weight < shoot elongation and leaf area. The critical activities, expressed as pZn = [minus]log(Zn[sup +2]), were [approximately]10.2 [+-] 0.2 for root dry weight, 10.1 [+-] 0.2 for leaf number and white root growth, 10.0 [+-] 0.2 for stem dry weight, 9.9 [+-] 0.2 for leaf dry weight, and 9.8 [+-] 0.2 for shoot growth and leaf area. Increases in growth were observed in response to Zn applications even in the absence of visible Zn-deficiency symptoms. Seedlings containing > 23 mg[center dot]kg[sup [minus]1] Zn in leaves did not respond to further additions of Zn to the nutrient solution. Zinc foliar sprays were less effective than Zn applications to the roots in alleviating severe Zn deficiency because foliar-absorbed Zn was not translocated from the top of the roots and thus could not correct Zn deficiency in the roots.

  5. Active uptake and extravesicular storage of m-iodobenzylguanidine in human neuroblastoma SK-N-SH cells

    SciTech Connect

    Smets, L.A.; Loesberg, C.; Janssen, M.; Metwally, E.A.; Huiskamp, R.

    1989-06-01

    Radioiodinated m-iodobenzylguanidine (MIBG), an analogue of the neurotransmitter norepinephrine (NE), is increasingly used in the diagnosis and treatment of neural crest tumors. Active uptake and subsequent retention of MIBG and NE was studied in human neuroblastoma SK-N-SH cells. Neuron-specific uptake of (125I)MIBG and (3H)NE saturated at extracellular concentration of 10(-6) M and exceeded by 20-30-fold that by passive diffusion alone. A minimum of 50% of accumulated MIBG remained permanently stored but the SK-N-SH cells were incapable of retaining recaptured (3H)NE. (125I)MIBG was displaced from intracellular binding sites by unlabeled MIBG with 10-fold higher potency than by unlabeled NE. MIBG stored in SK-N-SH cells was insensitive to depletion by the inhibitor of granular uptake reserpine (RSP) and was not precipitated in a granular fraction by differential centrifugation. Only few electron-dense granules were found in these cells by electron microscopy. In contrast, MIBG storage in PC-12 pheochromocytoma cells which contained many storage granules, was sensitive to RSP and part of accumulated drug was recovered in a granular fraction. Accordingly, storage of MIBG in the SK-N-SH neuroblastoma cells is predominantly extravesicular and thus essentially different from that of biogenic amines in normal adrenomedullary tissue or in pheochromocytoma tumors, while sharing with these tissues a common mechanism of active uptake.

  6. PAS kinase as a nutrient sensor in neuroblastoma and hypothalamic cells required for the normal expression and activity of other cellular nutrient and energy sensors.

    PubMed

    Hurtado-Carneiro, Verónica; Roncero, Isabel; Blazquez, Enrique; Alvarez, Elvira; Sanz, Carmen

    2013-12-01

    PAS kinase (PASK) is a nutrient sensor that is highly conserved throughout evolution. PASK-deficient mice reveal a metabolic phenotype similar to that described in S6 kinase-1 S6K1-deficient mice that are protected against obesity. Hypothalamic metabolic sensors, such as AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR), play an important role in feeding behavior, the homeostasis of body weight, and energy balance. These sensors respond to changes in nutrient levels in the hypothalamic areas involved in feeding behavior and in neuroblastoma N2A cells, and we have recently reported that those effects are modulated by the anorexigenic peptide glucagon-like peptide-1 (GLP-1). Here, we identified PASK in both N2A cells and rat VMH and LH areas and found that its expression is regulated by glucose and GLP-1. High levels of glucose decreased Pask gene expression. Furthermore, PASK-silenced N2A cells record an impaired response by the AMPK and mTOR/S6K1 pathways to changes in glucose levels. Likewise, GLP-1 effect on the activity of AMPK, S6K1, and other intermediaries of both pathways and the regulatory role at the level of gene expression were also blocked in PASK-silenced cells. The absence of response to low glucose concentrations in PASK-silenced cells correlates with increased ATP content, low expression of mRNA coding for AMPK upstream kinase LKB1, and enhanced activation of S6K1. Our findings indicate that, at least in N2A cells, PASK is a key kinase in GLP-1 actions and exerts a coordinated response with the other metabolic sensors, suggesting that PASK might play an important role in feeding behavior.

  7. The uptake and bioaccumulation of heavy metals by food plants, their effects on plants nutrients, and associated health risk: a review.

    PubMed

    Khan, Anwarzeb; Khan, Sardar; Khan, Muhammad Amjad; Qamar, Zahir; Waqas, Muhammad

    2015-09-01

    Heavy metal contamination is a globally recognized environmental issue, threatening human life very seriously. Increasing population and high demand for food resulted in release of various contaminants into environment that finally contaminate the food chain. Edible plants are the major source of diet, and their contamination with toxic metals may result in catastrophic health hazards. Heavy metals affect the human health directly and/or indirectly; one of the indirect effects is the change in plant nutritional values. Previously, a number of review papers have been published on different aspects of heavy metal contamination. However, no related information is available about the effects of heavy metals on the nutritional status of food plants. This review paper is focused upon heavy metal sources, accumulation, transfer, health risk, and effects on protein, amino acids, carbohydrates, fats, and vitamins in plants. The literature about heavy metals in food plants shows that both leafy and nonleafy vegetables are good accumulators of heavy metals. In nonleafy vegetables, the bioaccumulation pattern was leaf > root ≈ stem > tuber. Heavy metals have strong influence on nutritional values; therefore, plants grown on metal-contaminated soil were nutrient deficient and consumption of such vegetables may lead to nutritional deficiency in the population particularly living in developing countries which are already facing the malnutrition problems.

  8. PPARγ activation redirects macrophage cholesterol from fecal excretion to adipose tissue uptake in mice via SR-BI

    PubMed Central

    Toh, Sue-Anne; Millar, John S.; Billheimer, Jeffrey; Fuki, Ilia; Naik, Snehal U.; Macphee, Colin; Walker, Max; Rader, Daniel J.

    2011-01-01

    PPARγ agonists, used in the treatment of Type 2 diabetes, can raise HDL-cholesterol, therefore could potentially stimulate macrophage-to-feces reverse cholesterol transport (RCT). We aimed to test whether PPARγ activation promotes macrophage RCT in vivo. Macrophage RCT was assessed in mice using cholesterol loaded/3H-cholesterol labeled macrophages. PPARγ agonist GW7845 (20 mg/kg/day) did not change 3H-tracer plasma appearance, but surprisingly decreased fecal 3H-free sterol excretion by 43% (P < 0.01) over 48 h. Total free cholesterol efflux from macrophages to serum (collected from control and GW7845 groups) was not different, although ABCA1-mediated efflux was significantly higher with GW7845. To determine the effect of PPARγ activation on HDL cholesterol uptake by different tissues, the metabolic fate of HDL labeled with 3H-cholesteryl ether (CE) was also measured. We observed two-fold increase in HDL derived 3H-CE uptake by adipose tissue (P < 0.005) with concomitant 22% decrease in HDL derived 3H-CE uptake by the liver (P < 0.05) in GW7845 treated wild type mice. This was associated with a significant increase in SR-BI protein expression in adipose tissue, but not liver. The same experiment in SR-BI knockout mice, showed no difference in HDL derived 3H-CE uptake by adipose tissue or liver. In conclusion, PPARγ activation decreases the fecal excretion of macrophage derived cholesterol in mice. This is not due to inhibition of cholesterol efflux from macrophages, but rather involves redirection of effluxed cholesterol from liver towards adipose tissue uptake via SR-BI. This represents a novel mechanism for regulation of RCT and may extend the therapeutic implications of these ligands. PMID:21291868

  9. Effects of xylitol on carbohydrate digesting enzymes activity, intestinal glucose absorption and muscle glucose uptake: a multi-mode study.

    PubMed

    Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

    2015-03-01

    The present study investigated the possible mechanism(s) behind the effects of xylitol on carbohydrate digesting enzymes activity, muscle glucose uptake and intestinal glucose absorption using in vitro, ex vivo and in vivo experimental models. The effects of increasing concentrations of xylitol (2.5%-40% or 164.31 mM-2628.99 mM) on alpha amylase and alpha glucosidase activity in vitro and intestinal glucose absorption and muscle glucose uptake were investigated under ex vivo conditions. Additionally, the effects of an oral bolus dose of xylitol (1 g per kg BW) on gastric emptying and intestinal glucose absorption and digesta transit in the different segments of the intestinal tract were investigated in normal and type 2 diabetic rats at 1 hour after dose administration, when phenol red was used as a recovery marker. Xylitol exhibited concentration-dependent inhibition of alpha amylase (IC₅₀ = 1364.04 mM) and alpha glucosidase (IC₅₀ = 1127.52 mM) activity in vitro and small intestinal glucose absorption under ex vivo condition. Xylitol also increased dose dependent muscle glucose uptake with and without insulin, although the uptake was not significantly affected by the addition of insulin. Oral single bolus dose of xylitol significantly delayed gastric emptying, inhibited intestinal glucose absorption but increased the intestinal digesta transit rate in both normal and diabetic rats compared to their respective controls. The data of this study suggest that xylitol reduces intestinal glucose absorption via inhibiting major carbohydrate digesting enzymes, slowing gastric emptying and fastening the intestinal transit rate, but increases muscle glucose uptake in normal and type 2 diabetic rats.

  10. Nutrient scavenging activity and antagonistic factors of non-photobiont lichen-associated bacteria: a review.

    PubMed

    Sigurbjörnsdóttir, M Auður; Andrésson, Ólafur S; Vilhelmsson, Oddur

    2016-04-01

    Lichens are defined as the specific symbiotic structure comprising a fungus and a green alga and/or cyanobacterium. Up until recently, non-photobiont endothallic bacteria, while known to be present in large numbers, have generally been dismissed as functionally irrelevant cohabitants of the lichen thallus, or even environmental contaminants. Recent analyses of lichen metagenomes and innovative co-culture experiments have uncovered a functionally complex community that appears to contribute to a healthy lichen thallus in several ways. Lichen-associated bacteriomes are typically dominated by several lineages of Proteobacteria, some of which may be specific for lichen species. Recent work has implicated members of these lineages in several important ecophysiological roles. These include nutrient scavenging, including mobilization of iron and phosphate, nitrogen fixation, cellulase, xylanase and amylase activities, and oxidation of recalcitrant compounds, e.g. aromatics and aliphatics. Production of volatile organic compounds, conferring antibacterial and antifungal activity, has also been demonstrated for several lichen-associated isolates. In the present paper we review the nature of non-phototrophic endolichenic bacteria associated with lichens, and give insight into the current state of knowledge on their importance the lichen symbiotic association.

  11. Inactive lipoprotein lipase (LPL) alone increases selective cholesterol ester uptake in vivo, whereas in the presence of active LPL it also increases triglyceride hydrolysis and whole particle lipoprotein uptake.

    PubMed

    Merkel, Martin; Heeren, Jörg; Dudeck, Wiebke; Rinninger, Franz; Radner, Herbert; Breslow, Jan L; Goldberg, Ira J; Zechner, Rudolf; Greten, Heiner

    2002-03-01

    We have previously shown that transgenic expression of catalytically inactive lipoprotein lipase (LPL) in muscle (Mck-N-LPL) enhances triglyceride hydrolysis as well as whole particle lipoprotein and selective cholesterol ester uptake. In the current study, we have examined whether these functions can be performed by inactive LPL alone or require the presence of active LPL expressed in the same tissue. To study inactive LPL in the presence of active LPL in the same tissue, the Mck-N-LPL transgene was bred onto the heterozygous LPL-deficient (LPL1) background. At 18 h of age, Mck-N-LPL reduced triglycerides by 35% and markedly increased muscle lipid droplets. In adult mice, it reduced triglycerides by 40% and increased lipoprotein particle uptake into muscle by 60% and cholesterol ester uptake by 110%. To study inactive LPL alone, the Mck-N-LPL transgene was bred onto the LPL-deficient (LPL0) background. These mice die at approximately 24 h of age. At 18 h of age, in the absence of active LPL, inactive LPL expression did not diminish triglycerides nor did it result in the accumulation of muscle lipid droplets. To study inactive LPL in the absence of active LPL in the same tissue in adult animals, the Mck-N-LPL transgene was bred onto mice that only expressed active LPL in the heart (LPL0/He-LPL). In this case, Mck-N-LPL did not reduce triglycerides or increase the uptake of lipoprotein particles but did increase muscle uptake of chylomicron and very low density lipoprotein cholesterol ester by 40%. Thus, in the presence of active LPL in the same tissue, inactive LPL augments triglyceride hydrolysis and increases whole particle triglyceride-rich lipoprotein and selective cholesterol ester uptake. In the absence of active LPL in the same tissue, inactive LPL only mediates selective cholesterol ester uptake.

  12. The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

    PubMed

    Cerozi, Brunno da Silva; Fitzsimmons, Kevin

    2016-11-01

    The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants.

  13. Cooperation of taurine uptake and dopamine D1 receptor activation facilitates the induction of protein synthesis-dependent late LTP.

    PubMed

    Suárez, Luz M; Bustamante, Julián; Orensanz, Luís M; Martín del Río, Rafael; Solís, José M

    2014-04-01

    Co-activation of NMDA and dopamine receptors is required for the induction of the late phase of LTP (L-LTP) that is dependent on new protein synthesis. Other neuromodulatory substances may also contribute to this process. Here, we examined whether taurine is one of the neuromodulators contributing to L-LTP induction, since it is known that taurine uptake induces a long-lasting synaptic potentiation dependent on protein synthesis, and taurine uptake inhibition blocks L-LTP induced by tetanization. Experiments were conducted using rat hippocampal slices where field synaptic potentials were evoked and recorded in CA3-CA1 synapses. Taurine (1 mM) applied 10 min before a high frequency stimulation (HFS) train converted a transitory early-LTP (E-LTP) into an L-LTP dependent on protein synthesis. This taurine effect was blocked by a taurine uptake inhibitor. A facilitation of L-LTP induction was also obtained by pre-application of SKF38393, a D1/D5 dopamine receptor (D1R) agonist. In this case, LTP facilitation was not affected by the taurine uptake inhibitor. Nevertheless, when taurine and SKF38393 were simultaneously pre-applied at a concentration that individually did not modify E-LTP, they produced a synergistic mechanism that facilitated the induction of L-LTP with a sole HFS train. This facilitation of L-LTP was blocked by inhibiting either taurine uptake or D1R activation. Taurine and SKF38393 activated different signaling pathways to transform E-LTP into L-LTP. Taurine-induced L-LTP facilitation required MAPK activation, while D1R-agonist-induced facilitation depended mainly on PKA activation and partially on MAPK activation. On the other hand, the synergistic mechanisms induced by the cooperative action of taurine and SKF38393 were impaired by inhibitors against MAPK, PKA and PI3-K. This pharmacological profile resembles that displayed by L-LTP induced by three HFS trains at 10-min intervals. These results indicate that taurine uptake is necessary and

  14. Receptor binding and cellular uptake studies of macrophage migration inhibitory factor (MIF): use of biologically active labeled MIF derivatives.

    PubMed

    Kleemann, Robert; Grell, Matthias; Mischke, Ralf; Zimmermann, Gudrun; Bernhagen, Jürgen

    2002-03-01

    Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine for which a receptor has not been identified. That MIF has intracellular functions has been suggested by its enzymatic activity and constitutive expression profile. The discovery of functional MIF-c-Jun activation domain binding protein 1 (JAB1) binding has confirmed this notion and indicated that nonreceptor-based signaling mechanisms are important for MIF function. Here, we have generated and tested several biologically active labeled MIF derivatives to further define target protein binding by MIF and its cellular uptake characteristics. (35)S-MIF, biotinylated MIF, and fluoresceinated MIF were demonstrated to exhibit full biologic activity. Neither by applying a standard iodinated MIF preparation nor by using the biologically active (35)S-MIF derivative in receptor-binding studies were we able to measure any receptor-binding activity on numerous cells, confirming that uptake of MIF into target cells and MIF signaling can occur by receptor-independent pathways. When MIF derivatives were applied in cellular uptake studies, MIF was found to be endocytosed into both immune and nonimmune cells and targeted to the cytosol and lysosomes. The entry of MIF was temperature and energy dependent and was inhibited by monodansylcadaverine but not by ouabain. Endocytosed biotin-MIF bound JAB1 not only in macrophages, as shown previously, but also in nonimmune cells. A tagged MIF construct, MIF-enhanced green fluorescent protein (EGFP), was shown to be a valuable tool, as EGFP constructs of critical MIF cysteine mutants exhibited identical cellular localization properties to those of wild-type MIF (wtMIF). Our results indicate that MIF membrane receptors are not widely expressed, if at all, and suggest that the cellular uptake of MIF occurs by nonreceptor-mediated endocytosis rather than penetration. All the derivatives investigated, except for iodinated MIF, represent valuable tools for further MIF target

  15. Effects of arbuscular mycorrhizae on tomato yield, nutrient uptake, water relations, and soil carbon dynamics under deficit irrigation in field conditions.

    PubMed

    Bowles, Timothy M; Barrios-Masias, Felipe H; Carlisle, Eli A; Cavagnaro, Timothy R; Jackson, Louise E

    2016-10-01

    Plant strategies to cope with future droughts may be enhanced by associations between roots and soil microorganisms, including arbuscular mycorrhizal (AM) fungi. But how AM fungi affect crop growth and yield, together with plant physiology and soil carbon (C) dynamics, under water stress in actual field conditions is not well understood. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant nonmycorrhizal tomato genotype rmc were grown in an organic farm with a deficit irrigation regime and control regime that replaced evapotranspiration. AM increased marketable tomato yields by ~25% in both irrigation regimes but did not affect shoot biomass. In both irrigation regimes, MYC+ plants had higher plant nitrogen (N) and phosphorus (P) concentrations (e.g. 5 and 24% higher N and P concentrations in leaves at fruit set, respectively), 8% higher stomatal conductance (gs), 7% higher photosynthetic rates (Pn), and greater fruit set. Stem water potential and leaf relative water content were similar in both genotypes within each irrigation regime. Three-fold higher rates of root sap exudation in detopped MYC+ plants suggest greater capacity for water uptake through osmotic driven flow, especially in the deficit irrigation regime in which root sap exudation in rmc was nearly absent. Soil with MYC+ plants also had slightly higher soil extractable organic C and microbial biomass C at anthesis but no changes in soil CO2 emissions, although the latter were 23% lower under deficit irrigation. This study provides novel, field-based evidence for how indigenous AM fungi increase crop yield and crop water use efficiency during a season-long deficit irrigation and thus play an important role in coping with increasingly limited water availability in the future.

  16. Root Fungal Endophytes Enhance Heavy-Metal Stress Tolerance of Clethra barbinervis Growing Naturally at Mining Sites via Growth Enhancement, Promotion of Nutrient Uptake and Decrease of Heavy-Metal Concentration.

    PubMed

    Yamaji, Keiko; Watanabe, Yumiko; Masuya, Hayato; Shigeto, Arisa; Yui, Hiroshi; Haruma, Toshikatsu

    2016-01-01

    Clethra barbinervis Sieb. et Zucc. is a tree species that grows naturally at several mine sites and seems to be tolerant of high concentrations of heavy metals, such as Cu, Zn, and Pb. The purpose of this study is to clarify the mechanism(s) underlying this species' ability to tolerate the sites' severe heavy-metal pollution by considering C. barbinervis interaction with root fungal endophytes. We measured the heavy metal concentrations of root-zone soil, leaves, branches, and fine roots collected from mature C. barbinervis at Hitachi mine. We isolated fungal endophytes from surface-sterilized root segments, and we examined the growth, and heavy metal and nutrient absorption of C. barbinervis seedlings growing in sterilized mine soil with or without root fungal endophytes. Field analyses showed that C. barbinervis contained considerably high amounts of Cu, Zn, and Pb in fine roots and Zn in leaves. The fungi, Phialocephala fortinii, Rhizodermea veluwensis, and Rhizoscyphus sp. were frequently isolated as dominant fungal endophyte species. Inoculation of these root fungal endophytes to C. barbinervis seedlings growing in sterilized mine soil indicated that these fungi significantly enhanced the growth of C. barbinervis seedlings, increased K uptake in shoots and reduced the concentrations of Cu, Ni, Zn, Cd, and Pb in roots. Without root fungal endophytes, C. barbinervis could hardly grow under the heavy-metal contaminated condition, showing chlorosis, a symptom of heavy-metal toxicity. Our results indicate that the tree C. barbinervis can tolerate high heavy-metal concentrations due to the support of root fungal endophytes including P. fortinii, R. veluwensis, and Rhizoscyphus sp. via growth enhancement, K uptake promotion and decrease of heavy metal concentrations.

  17. Root Fungal Endophytes Enhance Heavy-Metal Stress Tolerance of Clethra barbinervis Growing Naturally at Mining Sites via Growth Enhancement, Promotion of Nutrient Uptake and Decrease of Heavy-Metal Concentration

    PubMed Central

    Shigeto, Arisa; Yui, Hiroshi; Haruma, Toshikatsu

    2016-01-01

    Clethra barbinervis Sieb. et Zucc. is a tree species that grows naturally at several mine sites and seems to be tolerant of high concentrations of heavy metals, such as Cu, Zn, and Pb. The purpose of this study is to clarify the mechanism(s) underlying this species’ ability to tolerate the sites’ severe heavy-metal pollution by considering C. barbinervis interaction with root fungal endophytes. We measured the heavy metal concentrations of root-zone soil, leaves, branches, and fine roots collected from mature C. barbinervis at Hitachi mine. We isolated fungal endophytes from surface-sterilized root segments, and we examined the growth, and heavy metal and nutrient absorption of C. barbinervis seedlings growing in sterilized mine soil with or without root fungal endophytes. Field analyses showed that C. barbinervis contained considerably high amounts of Cu, Zn, and Pb in fine roots and Zn in leaves. The fungi, Phialocephala fortinii, Rhizodermea veluwensis, and Rhizoscyphus sp. were frequently isolated as dominant fungal endophyte species. Inoculation of these root fungal endophytes to C. barbinervis seedlings growing in sterilized mine soil indicated that these fungi significantly enhanced the growth of C. barbinervis seedlings, increased K uptake in shoots and reduced the concentrations of Cu, Ni, Zn, Cd, and Pb in roots. Without root fungal endophytes, C. barbinervis could hardly grow under the heavy-metal contaminated condition, showing chlorosis, a symptom of heavy-metal toxicity. Our results indicate that the tree C. barbinervis can tolerate high heavy-metal concentrations due to the support of root fungal endophytes including P. fortinii, R. veluwensis, and Rhizoscyphus sp. via growth enhancement, K uptake promotion and decrease of heavy metal concentrations. PMID:28030648

  18. Repaglinide preserves nutrient-stimulated biosynthetic activity in rat pancreatic islets.

    PubMed

    Viñambres, C; Villanueva-Peñacarrillo, M L; Valverde, I; Malaisse, W J

    1996-01-01

    The meglitinide analogue repaglinide is a novel non-sulphonylurea insulinotropic agent which, like hypoglycaemic sulphonylureas, causes the closing of ATP-sensitive K+ channels in islet cells. We have now explored the effect of repaglinide upon proinsulin biosynthesis in rat pancreatic islets. Groups of eight islets each were incubated for 90 min in the presence of L-[4-(3)H]phenylalanine (4 microM) and glucose (2.8 or 16.7 mM), in the absence or presence of repaglinide (10 microM). A rise in glucose concentration caused a four-fold increase of the incorporation of L-[4-(3)H]phenylalanine into TCA-precipitable material. Repaglinide failed to adversely affect protein biosynthesis, whether at low or high glucose concentrations. Further characterization of the biosynthetic response was achieved by separation of the tritiated peptides by gel filtration. In the absence of repaglinide, the (pro)insulin/total ratio of tritiated peptides averaged 33.3 +/- 10.2 and 58.7 +/- 1.7% (n = 6 in both cases) at 2.8 and 16.7 mM D-glucose, respectively. Repaglinide again failed to significantly affect such ratios. In conclusion, repaglinide may offer the advantage over hypoglycaemic sulphonylureas of preserving nutrient-stimulated biosynthetic activity in pancreatic islet cells.

  19. Nutrient and nonnutrient components of legumes, and its chemopreventive activity: a review.

    PubMed

    Sánchez-Chino, Xariss; Jiménez-Martínez, Cristian; Dávila-Ortiz, Gloria; Álvarez-González, Isela; Madrigal-Bujaidar, Eduardo

    2015-01-01

    Legumes in combination with other products are the staple food for a large part of the world population, especially the low-income fragment, because their seeds provide valuable amounts of carbohydrates, fiber, and proteins, and have an important composition of essential amino acids, the sulphured amino acids being the limiting ones. Furthermore, legumes also have nonnutritional compounds that may decrease the absorption of nutrients or produce toxic effects; however, it has been reported that depending on the dose, these nonnutritional compounds also have different bioactivities as antioxidant, hypolipidemic, hypoglycemic, and anticarcinogenic agents, which have been proven in scientific studies. It has been observed that in countries with a high consumption of legumes, the incidence of colorectal cancer is lower. Some studies have shown that legume seeds are an alternative chemopreventive therapy against various cancers especially colon; this was verified in various animal models of induced by azoxymethane, a colon specific carcinogenic compound, in which a diet was supplemented with different concentrations of beans, lentils, chickpeas, or soybeans, mostly. These studies have proven the anticancer activity of legumes in early stages of carcinogenesis. Therefore, it is important to review the information available to elucidate the chemopreventive mechanisms of action of legume compounds.

  20. Comparative study of wastewater treatment and nutrient recycle via activated sludge, microalgae and combination systems.

    PubMed

    Wang, Liang; Liu, Jinli; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2016-07-01

    Algal-bacterial synergistic cultivation could be an optional wastewater treatment technology in temperate areas. In this study, a locally screened vigorous Chlorella strain was characterized and then it was used in a comparative study of wastewater treatment and nutrient recycle assessment via activated sludge (AS), microalgae and their combination systems. Chlorella sp. cultured with AS in light showed the best performance, in which case the removal efficiencies of COD, NH3-N and TP were 87.3%, 99.2% and 83.9%, respectively, within a short period of 1day. Algal-bacterial combination in light had the best settleability. Chlorella sp. contained biomass, could be processed to feed, fertilizer or fuel due to the improved quality (higher C/H/N) compared with sludge. PCR-DGGE analysis shows that two types of rhizobacteria, namely, Pseudomonas putida and Flavobacterium hauense were enriched in sludge when cultured with algae in light, serving as the basics for artificial consortium construction for improved wastewater treatment.

  1. Diagnosis of nutrient imbalances with vector analysis in agroforestry systems.

    PubMed

    Isaac, Marney E; Kimaro, Anthony A

    2011-01-01

    Agricultural intensification has had unintended environmental consequences, including increased nutrient leaching and surface runoff and other agrarian-derived pollutants. Improved diagnosis of on-farm nutrient dynamics will have the advantage of increasing yields and will diminish financial and environmental costs. To achieve this, a management support system that allows for site-specific rapid evaluation of nutrient production imbalances and subsequent management prescriptions is needed for agroecological design. Vector diagnosis, a bivariate model to depict changes in yield and nutritional response simultaneously in a single graph, facilitates identification of nutritional status such as growth dilution, deficiency, sufficiency, luxury uptake, and toxicity. Quantitative data from cocoa agroforestry systems and pigeonpea intercropping trials in Ghana and Tanzania, respectively, were re-evaluated with vector analysis. Relative to monoculture, biomass increase in cocoa ( L.) under shade (35-80%) was accompanied by a 17 to 25% decline in P concentration, the most limiting nutrient on this site. Similarly, increasing biomass with declining P concentrations was noted for pigeonpea [ (L). Millsp.] in response to soil moisture availability under intercropping. Although vector analysis depicted nutrient responses, the current vector model does not consider non-nutrient resource effects on growth, such as ameliorated light and soil moisture, which were particularly active in these systems. We revisit and develop vector analysis into a framework for diagnosing nutrient and non-nutrient interactions in agroforestry systems. Such a diagnostic technique advances management decision-making by increasing nutrient precision and reducing environmental issues associated with agrarian-derived soil contamination.

  2. Carnosic acid as a component of rosemary extract stimulates skeletal muscle cell glucose uptake via AMPK activation.

    PubMed

    Naimi, Madina; Vlavcheski, Filip; Murphy, Brennan; Hudlicky, Tomas; Tsiani, Evangelia

    2017-01-01

    Compounds that increase the activity of the energy sensor AMP-activated kinase (AMPK) have the potential to regulate blood glucose levels. Although rosemary extract (RE) has been reported to activate AMPK and reduce blood glucose levels in vivo, the chemical components responsible for these effects are not known. In the present study, we measured the levels of the polyphenol carnosic acid (CA) in RE and examined the effects and the mechanism of action of CA on glucose transport system in muscle cells. High performance liquid chromatography (HPLC) was used to measure the levels of CA in RE. Parental and GLUT4myc or GLUT1myc overexpressing L6 rat myotubes were used. Glucose uptake was assessed using [(3) H]-2-deoxy-d-glucose. Total and phosphorylated levels of Akt and AMPK were measured by immunoblotting. Plasma membrane GLUT4myc and GLUT1myc levels were examined using a GLUT translocation assay. Statistics included analysis of variance (ANOVA) followed by Tukey's post-hoc test. At concentrations found in rosemary extract, CA stimulated glucose uptake in L6 myotubes. At 2.0 μmol/L CA a response (226 ± 9.62% of control, P=.001), similar to maximum insulin (201 ± 7.86% of control, P=.001) and metformin (213 ± 10.74% of control, P=.001) was seen. Akt phosphorylation was not affected by CA while AMPK and ACC phosphorylation was increased and the CA-stimulated glucose uptake was significantly reduced by the AMPK inhibitor compound C. Plasma membrane GLUT4 or GLUT1 glucose transporter levels were not affected by CA. Our study shows increased muscle cell glucose uptake and AMPK activation by low CA concentrations, found in rosemary extract, indicating that CA may be responsible for the antihyperglycemic properties of rosemary extract seen in vivo.

  3. Chemical carcinogenesis in feral fish: uptake, activation, and detoxication of organic xenobiotics.

    PubMed Central

    Varanasi, U; Stein, J E; Nishimoto, M; Reichert, W L; Collier, T K

    1987-01-01

    The high prevalence of liver neoplasms in English sole (Parophrys vetulus) and substantially lower prevalence of neoplasms in a closely related species, starry flounder (Platichthys stellatus) captured from industrialized waterways, provide a unique opportunity to compare biochemical processes involved in chemical carcinogenesis in feral fish species. Because levels of aromatic hydrocarbons (AHs) in urban sediments are correlated with prevalences of liver neoplasms in English sole, we have initiated detailed studies to evaluate the effects of endogenous and exogenous factors on uptake, activation and detoxication of carcinogenic AHs, such as benzo[a]pyrene (BaP), using spectroscopic, chromatographic, and radiometric techniques. The results obtained thus far show that sole readily takes up AHs associated with sediment from urban areas and that the presence of other xenobiotics, such as PCBs, in sediment increases tissue concentrations of BaP metabolites. Extensive metabolism of BaP occurred whether sole was exposed to this AH via sediment, per os, or intraperitoneally. Substantial modification of hepatic DNA occurred and persisted for a period of 2-4 weeks after a single exposure to BaP. The level of covalent binding of BaP intermediates to hepatic DNA was 10-fold higher in juvenile than adult sole and 90-fold higher in juvenile sole than in Sprague-Dawley rat, a species which is resistant to BaP-induced hepatocarcinogenesis. The level of chemical modification of hepatic DNA in juvenile flounder was 2-4 fold lower than that for juvenile sole and concentration of BaP 7,8-diol glucuronide in bile of sole was significantly higher than that in flounder bile, although the rate of formation of BaP 7,8-diol by hepatic microsomes was comparable for both species. Moreover, liver microsomes from both species, in the presence of exogenous DNA, metabolized BaP into essentially a single adduct, identified as (+)anti-7,8-diol-9,10-epoxy-7,8,9,10-tetrahydroBaP-dG. These results

  4. Calorie restriction leads to greater Akt2 activity and glucose uptake by insulin-stimulated skeletal muscle from old rats

    PubMed Central

    Wang, Haiyan; Arias, Edward B.

    2016-01-01

    Skeletal muscle insulin resistance is associated with many common age-related diseases, but moderate calorie restriction (CR) can substantially elevate glucose uptake by insulin-stimulated skeletal muscle from both young and old rats. The current study evaluated the isolated epitrochlearis muscle from ∼24.5-mo-old rats that were either fed ad libitum (AL) or subjected to CR (consuming ∼65% of ad libitum, AL, intake beginning at ∼22.5 mo old). Some muscles were also incubated with MK-2206, a potent and selective Akt inhibitor. The most important results were that in isolated muscles, CR vs. AL resulted in 1) greater insulin-stimulated glucose uptake 2) that was accompanied by significantly increased insulin-mediated activation of Akt2, as indicated by greater phosphorylation on both Thr309 and Ser474 along with greater Akt2 activity, 3) concomitant with enhanced phosphorylation of several Akt substrates, including an Akt substrate of 160 kDa on Thr642 and Ser588, filamin C on Ser2213 and proline-rich Akt substrate of 40 kDa on Thr246, but not TBC1D1 on Thr596; and 4) each of the CR effects was eliminated by MK-2206. These data provide compelling new evidence linking greater Akt2 activation to the CR-induced elevation of insulin-stimulated glucose uptake by muscle from old animals. PMID:26739650

  5. Nutrient gradients in a granular activated carbon biofilter drives bacterial community organization and dynamics.

    PubMed

    Boon, Nico; Pycke, Benny F G; Marzorati, Massimo; Hammes, Frederik

    2011-12-01

    The quality of drinking water is ensured by hygienic barriers and filtration steps, such as ozonation and granular activated carbon (GAC) filtration. Apart from adsorption, GAC filtration involves microbial processes that remove biodegradable organic carbon from the ozonated ground or surface water and ensures biological stability of the treated water. In this study, microbial community dynamics in were monitored during the start-up and maturation of an undisturbed pilot-scale GAC filter at 4 depths (10, 45, 80 and 115 cm) over a period of 6 months. New ecological tools, based on 16S rRNA gene-DGGE, were correlated to filter performance and microbial activity and showed that the microbial gradients developing in the filter was of importance. At 10 cm from the top, receiving the freshly ozonated water with the highest concentration of nutrients, the microbial community dynamics were minimal and the species richness remained low. However, the GAC samples at 80-115 cm showed a 2-3 times higher species richness than the 10-45 cm samples. The highest biomass densities were observed at 45-80 cm, which corresponded with maximum removal of dissolved and assimilable organic carbon. Furthermore, the start-up period was clearly distinguishable using the Lorenz analysis, as after 80 days, the microbial community shifted to an apparent steady-state condition with increased evenness. This study showed that GAC biofilter performance is not necessarily correlated to biomass concentration, but rather that an elevated functionality can be the result of increased microbial community richness, evenness and dynamics.

  6. Expanding the menu for carnivorous plants: uptake of potassium, iron and manganese by carnivorous pitcher plants.

    PubMed

    Adlassnig, Wolfram; Steinhauser, Georg; Peroutka, Marianne; Musilek, Andreas; Sterba, Johannes H; Lichtscheidl, Irene K; Bichler, Max

    2009-12-01

    Carnivorous plants use animals as fertiliser substitutes which allow them to survive on nutrient deficient soils. Most research concentrated on the uptake of the prey's nitrogen and phosphorus; only little is known on the utilisation of other elements. We studied the uptake of three essential nutrients, potassium, iron and manganese, in three species of carnivorous pitcher plants (Cephalotus follicularis LaBilladiere, Sarracenia purpureaL., Heliamphora nutans Bentham). Using relatively short-lived and gamma-emitting radiotracers, we significantly improved the sensitivity compared to conventional protocols and gained the following results. We demonstrated the uptake of trace elements like iron and manganese. In addition, we found direct evidence for the uptake of potassium into the pitcher tissue. Potassium and manganese were absorbed to virtually 100% if offered in physiological concentrations or below in Cephalotus. Analysis of pitcher fluid collected in the natural habitat showed that uptake was performed here as efficiently as in the laboratory. The absorption of nutrients is an active process depending on living glandular cells in the pitcher epidermis and can be inhibited by azide. Unphysiologically high amounts of nutrients were taken up for a short time, but after a few hours the absorbing cells were damaged, and uptake stopped. Absorption rates of pitcher leaves from plants under controlled conditions varied highly, indicating that each trap is functionally independent. The comparison of minerals in typical prey with the plants' tissues showed that a complete coverage of the plants' needs by prey capture is improbable.

  7. The Design, Synthesis and Structure-Activity Relationship of Mixed Serotonin, Norepinephrine and Dopamine Uptake Inhibitors

    NASA Astrophysics Data System (ADS)

    Chen, Zhengming; Yang, Ji; Skolnick, Phil

    The evolution of antidepressants over the past four decades has involved the replacement of drugs with a multiplicity of effects (e.g., TCAs) by those with selective actions (i.e., SSRIs). This strategy was employed to reduce the adverse effects of TCAs, largely by eliminating interactions with certain neurotransmitters or receptors. Although these more selective compounds may be better tolerated by patients, selective drugs, specifically SSRIs, are not superior to older drugs in treating depressed patients as measured by response and remission rates. It may be an advantage to increase synaptic levels of both serotonin and norepinephrine, as in the case of dual uptake inhibitors like duloxetine and venlafaxine. An important recent development has been the emergence of the triple-uptake inhibitors (TUIs/SNDRIs), which inhibit the uptake of the three neurotransmitters most closely linked to depression: serotonin, norepinephrine, and dopamine. Preclinical studies and clinical trials indicate that a drug inhibiting the reuptake of all three of these neurotransmitters could produce more rapid onset of action and greater efficacy than traditional antidepressants. This review will detail the medicinal chemistry involved in the design, synthesis and discovery of mixed serotonin, norepinephrine and dopamine transporter uptake inhibitors.

  8. Effect of anesthetics on microglial activation and nanoparticle uptake: Implications for drug delivery in traumatic brain injury.

    PubMed

    Kannan, Gokul; Kambhampati, Siva P; Kudchadkar, Sapna R

    2017-03-21

    Traumatic brain injury (TBI) is a serious public health problem, often with devastating consequences for patients and their families. Affordable and timely therapies can have a substantial impact on outcomes in severe TBI. Despite the common use of sedatives and anesthetics in the acute phase of TBI management, their effect on glial cells is not well understood. We investigated the effect of a commonly used sedative, pentobarbital, on glial cells and their uptake of nanoparticles. First, we studied how pentobarbital affects BV2 mouse microglial cells in culture. The cell morphology was imaged by confocal microscopy and analyzed. Our results suggest that microglia change to a more swollen, 'activated' shape with pentobarbital (cell area increased by approximately 20%, p<0.001). Such glial activation may have negative implications for the ability of the injured brain to clear edema. Second, we investigated how pentobarbital treatment affected nanoparticle uptake. BV-2 mouse microglial cells in the presence and absence of pentobarbital were treated with fluorescently-labeled, hydroxyl-functionalized poly(amidoamine) dendrimer nanoparticles (Dendrimer-Cy5). We demonstrated that the presence of pentobarbital increased the dendrimer nanoparticle uptake significantly (~2-fold both 2 and 6h following treatment). This semi-quantitative fluorescence assessment was broadly consistent among confocal image analysis, flow cytometry, and fluorescence quantification of cell-extracted dendrimer-Cy5. Although anesthetics appear to activate microglia, the increased uptake of dendrimer nanoparticles in their presence can be exploited to deliver drug-loaded nanoparticles directly to microglia after TBI. These drugs could restore glial and glymphatic function, enabling efficient drainage of waste and fluid from the brain and effectively improving recovery after TBI. A key future direction is to validate these findings in TBI models.

  9. A Rice Mutant Defective in Si Uptake1

    PubMed Central

    Ma, Jian Feng; Tamai, Kazunori; Ichii, Masahiko; Wu, Guo Feng

    2002-01-01

    Rice (Oryza sativa) accumulates silicon (Si) in the tops to levels up to 10.0% of shoot dry weight, but the mechanism responsible for high Si uptake by rice roots is not understood. We isolated a rice mutant (GR1) that is defective in active Si uptake by screening M2 seeds (64,000) of rice cv Oochikara that were treated with 10−3 m sodium azide for 6 h at 25oC. There were no phenotypic differences between wild type (WT) and GR1 except that the leaf blade of GR1 remained droopy when Si was supplied. Uptake experiments showed that Si uptake by GR1 was significantly lower than that by WT at both low and high Si concentrations. However, there was no difference in the uptake of other nutrients such as phosphorus and potassium. Si concentration in the xylem sap of WT was 33-fold that of the external solution, but that of GR1 was 3-fold higher than the external solution at 0.15 mm Si. Si uptake by WT was inhibited by metabolic inhibitors including NaCN and 2,4-dinitrophenol and by low temperature, whereas Si uptake by GR1 was not inhibited by these agents. These results suggest that an active transport system for Si uptake is disrupted in GR1. Analysis of F2 populations between GR1 and WT showed that roots with high Si uptake and roots with low Si uptake segregated at a 3:1 ratio, suggesting that GR1 is a recessive mutant of Si uptake. PMID:12481095

  10. Ethanolic extract of Allium cepa stimulates glucose transporter typ 4-mediated glucose uptake by the activation of insulin signaling.

    PubMed

    Gautam, Sudeep; Pal, Savita; Maurya, Rakesh; Srivastava, Arvind K

    2015-02-01

    The present work was undertaken to investigate the effects and the molecular mechanism of the standardized ethanolic extract of Allium cepa (onion) on the glucose transport for controlling diabetes mellitus. A. cepa stimulates glucose uptake by the rat skeletal muscle cells (L6 myotubes) in both time- and dose-dependent manners. This effect was shown to be mediated by the increased translocation of glucose transporter typ 4 protein from the cytoplasm to the plasma membrane as well as the synthesis of glucose transporter typ 4 protein. The effect of A. cepa extract on glucose transport was stymied by wortmannin, genistein, and AI½. In vitro phosphorylation analysis revealed that, like insulin, A. cepa extract also enhances the tyrosine phosphorylation of the insulin receptor-β, insulin receptor substrate-1, and the serine phosphorylation of Akt under both basal and insulin-stimulated conditions without affecting the total amount of these proteins. Furthermore, it is also shown that the activation of Akt is indispensable for the A. cepa-induced glucose uptake in L6 myotubes. Taken together, these findings provide ample evidence that the ethanolic extract of A. cepa stimulates glucose transporter typ 4 translocation-mediated glucose uptake by the activation of the phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt dependent pathway.

  11. Ionic status, calcium uptake, and Ca2+-ATPase activity during early development in the purple sea urchin (Strongylocentrotus purpuratus).

    PubMed

    Tellis, Margaret S; Lauer, Mariana M; Nadella, Sunita; Bianchini, Adalto; Wood, Chris M

    2013-10-01

    Ionic status during early development was investigated in the purple sea urchin. Whole body cation concentrations (Ca(2+), Na(+), K(+), Mg(2+)), unidirectional Ca(2+) uptake rates measured with (45)Ca(2+), Ca(2+)-ATPase activity, and growth were examined at 12h intervals over the first 96h of development. Whole body Ca(2+) concentration was low initially but increased steadily by >15-fold through to the pluteus stage. Whole body Mg(2+), K(+) and Na(+) levels exhibited diverse patterns, but all increased at 72-96h. Ca(2+) uptake rates were low during initial cell cleavages at 12h but increased greatly at blastulation (24h) and then again at gastrulation (48h), declining thereafter in the pluteus stage, but increasing slightly at 96h. Ca(2+)-ATPase activity was initially low but increased at blastulation through gastrulation (24-48h) but declined thereafter in the pluteus stage. Embryonic weights did not change over most of development, but were significantly higher at 96h. Overall, the gastrulation stage displayed the most pronounced changes, as Ca(2+) uptake and accumulation and Ca(2+)-ATPase levels were the highest at this stage, likely involved in mineralization of the spicule. Biomarkers of Ca(2+) metabolism may be good endpoints for potential future toxicity studies.

  12. Active auxin uptake by zucchini membrane vesicles: quantitation using ESR volume and delta pH determinations

    SciTech Connect

    Lomax, T.L.; Mehlhorn, R.J.; Briggs, W.R.

    1985-10-01

    Closed and pH-tight membrane vesicles prepared from hypocotyls of 5-day-old dark-grown seedlings of Cucurbita pepo accumulate the plant growth hormone indole-3-acetic acid along an imposed proton gradient (pH low outside, high inside). The use of electron paramagnetic spin probes permitted quantitation both of apparent vesicle volume and magnitude of the pH gradient. Under the experimental conditions used, hormone accumulation was at minimum 20-fold, a value 4 times larger than what one would predict if accumulation reflected only diffusional equilibrium at the measured pH gradient. It is concluded that hormone uptake is an active process, with each protonated molecule of hormone accompanied by an additional proton. Experiments with ionophores confirm that it is the pH gradient itself which drives the uptake.

  13. The specific requirement for sodium chloride for the active uptake of l-glutamate by Halobacterium salinarium

    PubMed Central

    Stevenson, J.

    1966-01-01

    1. Uptake of l-glutamate by Halobacterium salinarium is dependent on high concentrations of sodium chloride in the environment. When the sodium chloride is replaced by isomolar concentrations of potassium chloride, sodium acetate or potassium acetate, only negligible uptake occurs. 2. Most of the glutamate taken up can be shown to be in the cells in the free state and at a concentration of at least 50 times that in the medium. Sodium chloride is therefore required for an active transport of the glutamate into the cells. 3. The question whether sodium chloride is essential for the actual migration of glutamate across the cell envelope or for the mechanism supplying energy for this migration is discussed on the basis of experiments on endogenous respiration and with inhibitors. PMID:5947144

  14. Nutrient addition modifies phosphatase activities along an altitudinal gradient in a tropical montane forest in Southern Ecuador

    NASA Astrophysics Data System (ADS)

    Dietrich, Karla; Spoeri, Elena; Oelmann, Yvonne

    2016-02-01

    Atmospheric nutrient deposition and climate change are expected to endanger the diversity of tropical forest ecosystems. Nitrogen (N) deposition might influence nutrient fluxes beyond the N cycle by a concomitant increased demand for other nutritional elements such as phosphorus (P). Organisms might respond to the increased P demand by enhanced activity of enzymes involved in releasing inorganic P from organic matter (OM). Our aims were to assess the effect of i) climate shifts (approximated by an altitudinal gradient), and ii) nutrient addition (N, P, N+P) on phosphatase activity (PA) in organic layer and mineral soil of a tropical montane rainforest in Southern Ecuador. A nutrient manipulation experiment (NUMEX) was set up along an altitudinal gradient (1000, 2000, and 3000 m a.s.l.). We determined PA and inorganic and total P concentrations. PA at 1000 m was significantly lower (mean ± standard error: 48 ± 20 µmol p-NP g-1 dm h-1) as compared to 2000 m and 3000 m (119 ± 11 and 137 ± 19, respectively). One explanation might be that very rapid decomposition of OM at 1000 m results in very thin organic layers reducing the stabilization of enzymes and thus, resulting in leaching loss of enzymes under the humid tropical climate. We found no effect of N addition on PA neither in the organic layer nor in mineral soil, probably because of the low nutrient addition rates that showed ambiguous results so far on productivity measures as a proxy for P demand. In the organic layers of P and N+P treatments, we found decreased PA and increased concentrations of inorganic P. This indicates that the surplus of inorganic P reduced the biosynthesis of phosphatase enzymes. PA in megadiverse montane rainforests is likely to be unaffected by increased atmospheric N deposition but reduced upon atmospheric P deposition.

  15. Changes in Stoichiometry, Cellular RNA, and Alkaline Phosphatase Activity of Chlamydomonas in Response to Temperature and Nutrients

    PubMed Central

    Hessen, Dag O.; Hafslund, Ola T.; Andersen, Tom; Broch, Catharina; Shala, Nita K.; Wojewodzic, Marcin W.

    2017-01-01

    Phytoplankton may respond both to elevated temperatures and reduced nutrients by changing their cellular stoichiometry and cell sizes. Since increased temperatures often cause increased thermal stratification and reduced vertical flux of nutrients into the mixed zone, it is difficult to disentangle these drivers in nature. In this study, we used a factorial design with high and low levels of phosphorus (P) and high and low temperature to assess responses in cellular stoichiometry, levels of RNA, and alkaline phosphatase activity (APA) in the chlorophyte Chlamydomonas reinhardtii. Growth rate, C:P, C:N, N:P, RNA, and APA all responded primarily to P treatment, but except for N:P and APA, also temperature contributed significantly. For RNA, the contribution from temperature was particularly strong with higher cellular levels of RNA at low temperatures, suggesting a compensatory allocation to ribosomes to maintain protein synthesis and growth. These experiments suggest that although P-limitation is the major determinant of growth rate and cellular stoichiometry, there are pronounced effects of temperature also via interaction with P. At the ecosystem level, nutrients and temperature will thus interact, but temperatures would likely exert a stronger impact on these phytoplankton traits indirectly via its force on stratification regimes and vertical nutrient fluxes. PMID:28167934

  16. Changes in Stoichiometry, Cellular RNA, and Alkaline Phosphatase Activity of Chlamydomonas in Response to Temperature and Nutrients.

    PubMed

    Hessen, Dag O; Hafslund, Ola T; Andersen, Tom; Broch, Catharina; Shala, Nita K; Wojewodzic, Marcin W

    2017-01-01

    Phytoplankton may respond both to elevated temperatures and reduced nutrients by changing their cellular stoichiometry and cell sizes. Since increased temperatures often cause increased thermal stratification and reduced vertical flux of nutrients into the mixed zone, it is difficult to disentangle these drivers in nature. In this study, we used a factorial design with high and low levels of phosphorus (P) and high and low temperature to assess responses in cellular stoichiometry, levels of RNA, and alkaline phosphatase activity (APA) in the chlorophyte Chlamydomonas reinhardtii. Growth rate, C:P, C:N, N:P, RNA, and APA all responded primarily to P treatment, but except for N:P and APA, also temperature contributed significantly. For RNA, the contribution from temperature was particularly strong with higher cellular levels of RNA at low temperatures, suggesting a compensatory allocation to ribosomes to maintain protein synthesis and growth. These experiments suggest that although P-limitation is the major determinant of growth rate and cellular stoichiometry, there are pronounced effects of temperature also via interaction with P. At the ecosystem level, nutrients and temperature will thus interact, but temperatures would likely exert a stronger impact on these phytoplankton traits indirectly via its force on stratification regimes and vertical nutrient fluxes.

  17. Physiological and biochemical responses of Suaeda fruticosa to cadmium and copper stresses: growth, nutrient uptake, antioxidant enzymes, phytochelatin, and glutathione levels.

    PubMed

    Bankaji, I; Caçador, I; Sleimi, N

    2015-09-01

    Environmental pollution by trace metal elements (TMEs) is a serious problem worldwide, increasing in parallel with the development of human technology. The present research aimed to examine the response of halophytic species Suaeda fruticosa to oxidative stress posed by combined abiotic stresses. Plants have been grown for 1 month with an irrigation solution supplemented with 200 mM NaCl and 400 μM Cd(2+) or 400 μM Cu(2+). The level of glutathione (GSH), phytochelatins (PCs), and antioxidant enzyme activities [ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and catalase (CAT)] as well as lipid peroxidation was studied to see the stress exerted by the TME and the level of tolerance and detoxification strategy adopted by S. fruticosa. Relative growth rate (RGR) decreased under Cd(2+) stress in this species, whereas Cu(2+) did not have any impact on S. fruticosa performance. Cd(2+) or Cu(2+) enhanced malondialdehyde, suggesting reactive oxygen species-induced disruption of membrane integrity and oxidative stress in S. fruticosa. On the other hand, the activities of the antioxidant enzymes CAT, APX, and GPX diminished and mineral nutrition was disturbed by metal stress. S. fruticosa was able to synthesize PCs in response to TME toxicity. However, data indicate that GSH levels underwent a significant decrease in roots and leaves of S. fruticosa stressed by Cd(2+) or Cu(2+). The GSH depletion accompanied by the increase of phytochelatin concentration suggests the involvement of GSH in the synthesis of phytochelatins.

  18. Active principle of swine prostate extract: I. Isolation of active principle activating prostatic acid phosphatase and its effect on testosterone uptake of the prostate in castrated rats.

    PubMed

    Yoshida, Y; Mori, H; Inami, K; Koda, A

    1991-07-01

    There have been several reports concerning the therapeutic effect of an extract from animal prostates on benign prostatic hypertrophy. Previously, we reported that the swine prostate extract (PE) had the activity to enhance human prostatic acid phosphatase (PAPase) activity in vitro, and to increase the muscular tonicity of the urinary bladder by directly acting upon vesical muscles, suggesting that PE have an activity to elevate the intravesical voiding pressure in vivo. In the present study, it was attempted to isolate such an active principle of PE as activates human prostatic acid phosphatase (PAPase). The finally purified PE (PPE) was assessed as to some physico-chemical and pharmacological properties. 1) PPE was found to be a peptide with a molecular weight of about 8,800, composed largely of neutral amino acids (approximately 70%) and few of aromatic amino acids. 2) PPE activated PAPase in a dose-dependent fashion, resulting in an increase of the enzyme activity approximately twice in a dose of 2 X 10(-5) g/ml of PPE. Furthermore, PPE recovered PAPase activity dose-dependently from the 50% inhibition by 2 X 10(-3) M L-tartaric acid. 3) In castrated rats, the 3H-testosterone uptake of the prostate was significantly suppressed by the oral administration of PPE. PPE might be one of active principles of PE for the therapeutic effect on prostatic hypertrophy.

  19. Tobacco mosaic virus efficiently targets DC uptake, activation and antigen-specific T cell responses in vivo.

    PubMed

    Kemnade, Jan Ole; Seethammagari, Mamatha; Collinson-Pautz, Mathew; Kaur, Hardeep; Spencer, David M; McCormick, Alison A

    2014-07-16

    Over the past 20 years, dendritic cells (DCs) have been utilized to activate immune responses capable of eliminating cancer cells. Currently, ex vivo DC priming has been the mainstay of DC cancer immunotherapies. However, cell-based treatment modalities are inherently flawed due to a lack of standardization, specialized facilities and personnel, and cost. Therefore, direct modes of DC manipulation, circumventing the need for ex vivo culture, must be investigated. To facilitate the development of next-generation, in vivo targeted DC vaccines, we characterized the DC interaction and activation potential of the Tobacco Mosaic virus (TMV), a plant virus that enjoys a relative ease of production and the ability to deliver protein payloads via surface conjugation. In this study we show that TMV is readily taken up by mouse bone marrow-derived DCs, in vitro. Footpad injection of fluorophore-labeled TMV reveals preferential uptake by draining lymph node resident DCs in vivo. Uptake leads to activation, as measured by the upregulation of key DC surface markers. When peptide antigen-conjugated TMV is injected into the footpad of mice, DC-mediated uptake and activation leads to robust antigen-specific CD8(+) T cell responses, as measured by antigen-specific tetramer analysis. Remarkably, TMV priming induced a greater magnitude T cell response than Adenovirus (Ad) priming. Finally, TMV is capable of boosting either Ad-induced or TMV-induced antigen-specific T cell responses, demonstrating that TMV, uniquely, does not induce neutralizing self-immunity. Overall, this study elucidates the in vivo DC delivery and activation properties of TMV and indicates its potential as a vaccine vector in stand alone or prime-boost strategies.

  20. Chasing Nutrients with an Arctic Sedge

    NASA Astrophysics Data System (ADS)

    Iverson, S. L.; Schimel, J.

    2013-12-01

    Climate change has put the Arctic into a state of flux. Understanding the effects an altered climate will have on vegetation and nutrient cycling requires more knowledge of the key plant and soil functions of major arctic ecosystems. One of these ecosystems, moist acidic tussock tundra, is dominated by a single plant species, the tussock-forming sedge Eriophorum vaginatum. This plant has unusual underground biomass: long, fast-growing, non-branching, non-mycorrhizal roots. In contrast to many other plants in nutrient-limiting environments, this sedge is highly successful without maximizing its root surface area to volume ratio. The benefits of this growth strategy to the plants and its effects on the accompanying soil-microbe-plant relationships are not fully understood. One possibility is that the roots may help the plant take advantage of nutrients released into the active layer of soil as it thaws in the spring. The roots may also stimulate microbial activity, increasing nutrient turnover and availability. A study was undertaken to explore the nitrogen (N) and carbon (C) dynamics in these plants, as well as the microbial populations associated with active E. vaginatum roots. Intact tussock microcosms (plant and accompanying soil) were removed from the tundra and cultivated in transparent boxes. Half the plants were kept in light to encourage photosynthesis (and thus greater plant activity), while the other half was kept in the dark to inhibit it. Using a 15N isotopic tracer injected at the extremity of root penetration into the soil, the N uptake capacity of E. vaginatum roots at depth was explored. This uptake capacity is compared to measures of plant activity, microbial activity, and soil solution chemistry in order to paint a clearer picture of the role of E. vaginatum in the soil ecosystem.

  1. Facilitating Mitochondrial Calcium Uptake Improves Activation-Induced Cerebral Blood Flow and Behavior after mTBI

    PubMed Central

    Murugan, Madhuvika; Santhakumar, Vijayalakshmi; Kannurpatti, Sridhar S.

    2016-01-01

    Mild to moderate traumatic brain injury (mTBI) leads to secondary neuronal loss via excitotoxic mechanisms, including mitochondrial Ca2+ overload. However, in the surviving cellular population, mitochondrial Ca2+ influx, and oxidative metabolism are diminished leading to suboptimal neuronal circuit activity and poor prognosis. Hence we tested the impact of boosting neuronal electrical activity and oxidative metabolism by facilitating mitochondrial Ca2+ uptake in a rat model of mTBI. In developing rats (P25-P26) sustaining an mTBI, we demonstrate post-traumatic changes in cerebral blood flow (CBF) in the sensorimotor cortex in response to whisker stimulation compared to sham using functional Laser Doppler Imaging (fLDI) at adulthood (P67-P73). Compared to sham, whisker stimulation-evoked positive CBF responses decreased while negative CBF responses increased in the mTBI animals. The spatiotemporal CBF changes representing underlying neuronal activity suggested profound changes to neurovascular activity after mTBI. Behavioral assessment of the same cohort of animals prior to fLDI showed that mTBI resulted in persistent contralateral sensorimotor behavioral deficit along with ipsilateral neuronal loss compared to sham. Treating mTBI rats with Kaempferol, a dietary flavonol compound that enhanced mitochondrial Ca2+ uptake, eliminated the inter-hemispheric asymmetry in the whisker stimulation-induced positive CBF responses and the ipsilateral negative CBF responses otherwise observed in the untreated and vehicle-treated mTBI animals in adulthood. Kaempferol also improved somatosensory behavioral measures compared to untreated and vehicle treated mTBI animals without augmenting post-injury neuronal loss. The results indicate that reduced mitochondrial Ca2+ uptake in the surviving populations affect post-traumatic neural activation leading to persistent behavioral deficits. Improvement in sensorimotor behavior and spatiotemporal neurovascular activity following kaempferol

  2. Constituents from Cistus salvifolius (Cistaceae) activate peroxisome proliferator-activated receptor-γ but not -δ and stimulate glucose uptake by adipocytes.

    PubMed

    Kühn, Claudia; Arapogianni, Niki Eliza; Halabalaki, Maria; Hempel, Jana; Hunger, Nicole; Wober, Jannette; Skaltsounis, Alexios Leandros; Vollmer, Günter

    2011-03-01

    A number of medicinal/culinary herbs have been reported to improve glucose metabolism and to yield hypoglycemic effects in patients with diabetes. Since stimulation of insulin sensitivity appears to be a potential mechanism, peroxisome proliferator-activated receptor (PPAR) γ is a likely target molecule for small lipophilic compounds derived from endogenous metabolism and nutrition. Functionally, PPAR γ integrates the control of energy, lipid, and glucose homeostasis. In addition, PPAR δ activity is involved in energy expenditure. Therefore the aim of this study was to investigate whether PPAR γ and PPAR δ as well as the stimulation of glucose uptake is activated by botanical products. CISTUS SALVIFOLIUS (Cistaceae) has been identified as a candidate botanical in a preliminary screening of extracts from medicinal plants of Greek flora. In a bioguided approach, crude extracts, fractions and in the end purified compounds have been evaluated for PPAR γ and PPAR δ specific activities using cell-based transactivation assays. Glucose uptake was measured by nonradioactive 2-[ N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) uptake. Concerning PPAR γ several extracts induced reporter gene activity, and clear dose-response patterns (0.1-100 µg/mL) could be established in the case of the cyclohexane and dichloromethane extracts. Isolation of individual compounds from the cyclohexane extract revealed that at least 6 out of 7 compounds isolated were active with TRANS-cinnamic acid showing a clear dose-response pattern. In contrast, they were found to be inactive on PPAR δ. The same compounds, however, were also active in stimulating glucose uptake into 3T3-L1 adipocytes. In summary, the bioguided fractionation of CISTUS SALVIFOLIUS yields PPAR γ stimulating metabolites with differing chemical natures. In conclusion, PPAR γ represents a candidate molecule for the mediation of improvement of glucose metabolism by botanical/nutritional products.

  3. Endoplasmic reticulum potassium-hydrogen exchanger and small conductance calcium-activated potassium channel activities are essential for ER calcium uptake in neurons and cardiomyocytes.

    PubMed

    Kuum, Malle; Veksler, Vladimir; Liiv, Joanna; Ventura-Clapier, Renee; Kaasik, Allen

    2012-02-01

    Calcium pumping into the endoplasmic reticulum (ER) lumen is thought to be coupled to a countertransport of protons through sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) and the members of the ClC family of chloride channels. However, pH in the ER lumen remains neutral, which suggests a mechanism responsible for proton re-entry. We studied whether cation-proton exchangers could act as routes for such a re-entry. ER Ca(2+) uptake was measured in permeabilized immortalized hypothalamic neurons, primary rat cortical neurons and mouse cardiac fibers. Replacement of K(+) in the uptake solution with Na(+) or tetraethylammonium led to a strong inhibition of Ca(2+) uptake in neurons and cardiomyocytes. Furthermore, inhibitors of the potassium-proton exchanger (quinine or propranolol) but not of the sodium-proton exchanger reduced ER Ca(2+) uptake by 56-82%. Externally added nigericin, a potassium-proton exchanger, attenuated the inhibitory effect of propranolol. Inhibitors of small conductance calcium-sensitive K(+) (SK(Ca)) channels (UCL 1684, dequalinium) blocked the uptake of Ca(2+) by the ER in all preparations by 48-94%, whereas inhibitors of other K(+) channels (IK(Ca), BK(Ca) and K(ATP)) had no effect. Fluorescence microscopy and western blot analysis revealed the presence of both SK(Ca) channels and the potassium-proton exchanger leucine zipper-EF-hand-containing transmembrane protein 1 (LETM1) in ER in situ and in the purified ER fraction. The data obtained demonstrate that SK(Ca) channels and LETM1 reside in the ER membrane and that their activity is essential for ER Ca(2+) uptake.

  4. Esterification of Ginsenoside Rh2 Enhanced Its Cellular Uptake and Antitumor Activity in Human HepG2 Cells.

    PubMed

    Chen, Fang; Deng, Ze-Yuan; Zhang, Bing; Xiong, Zeng-Xing; Zheng, Shi-Lian; Tan, Chao-Li; Hu, Jiang-Ning

    2016-01-13

    Our previous research had indicated that the octyl ester derivative of ginsenoside Rh2 (Rh2-O) might have a higher bioavailability than Rh2 in the Caco-2 cell line. The aim of this study was to investigate the cellular uptake and antitumor effects of Rh2-O in human HepG2 cells as well as its underlying mechanism compared with Rh2. Results showed that Rh2-O exhibited a higher cellular uptake (63.24%) than Rh2 (36.76%) when incubated with HepG2 cells for 24 h. Rh2-O possessed a dose- and time-dependent inhibitory effect against the proliferation of HepG2 cells. The IC50 value of Rh2-O for inhibition of HepG2 cell proliferation was 20.15 μM, which was roughly half the value of Rh2. Rh2-O induced apoptosis of HepG2 cells through a mitochondrial-mediated intrinsic pathway. In addition, the accumulation of ROS was detected in Rh2-O-treated HepG2 cells, which participated in the apoptosis of HepG2 cells. Conclusively, the findings above all suggested that Rh2-O as well as Rh2 inducing HepG2 cells apoptosis might involve similar mechanisms; however, Rh2-O had better antitumor activities than Rh2, probably due to its higher cellular uptake.

  5. Leaf Stable Isotope and Nutrient Status of Temperate Mangroves As Ecological Indicators to Assess Anthropogenic Activity and Recovery from Eutrophication

    PubMed Central

    Gritcan, Iana; Duxbury, Mark; Leuzinger, Sebastian; Alfaro, Andrea C.

    2016-01-01

    We measured nitrogen stable isotope values (δ15N), and total phosphorus (%P) and total nitrogen (%N) contents in leaves of the temperate mangrove (Avicennia marina sp. australasica) from three coastal ecosystems exposed to various levels of human impact (Manukau, high; Mangawhai, low; and Waitemata, intermediate) in northern New Zealand. We measured δ15N values around 10‰ in environments where the major terrestrial water inputs are sewage. The highest average total nitrogen contents and δ15N values were found in the Auckland city region (Manukau Harbour) at 2.2%N and 9.9‰, respectively. The lowest values were found in Mangawhai Harbour, situated about 80 km north of Auckland city, at 2.0%N and 5.2‰, respectively. In the Waitemata Harbour, also located in Auckland city but with less exposure to human derived sewage inputs, both parameters were intermediate, at 2.1%N and 6.4‰. Total phosphorus contents did not vary significantly. Additionally, analysis of historical mangrove leaf herbarium samples obtained from the Auckland War Memorial Museum indicated that a reduction in both leaf total nitrogen and δ15N content has occurred over the past 100 years in Auckland’s harbors. Collectively, these results suggest that anthropogenically derived nitrogen has had a significant impact on mangrove nutrient status in Auckland harbors over the last 100 years. The observed decrease in nitrogenous nutrients probably occurred due to sewage system improvements. We suggest that mangrove plant physiological response to nutrient excess could be used as an indicator of long-term eutrophication trends. Monitoring leaf nutrient status in mangroves can be used to assess environmental stress (sewage, eutrophication) on coastal ecosystems heavily impacted by human activities. Moreover, nitrogen and phosphorus leaf contents can be used to assess levels of available nutrients in the surrounding environments. PMID:28066477

  6. Dodeca-2(E),4(E)-dienoic acid isobutylamide enhances glucose uptake in 3T3-L1 cells via activation of Akt signaling.

    PubMed

    Choi, Kyeong-Mi; Kim, Wonkyun; Hong, Jin Tae; Yoo, Hwan-Soo

    2017-02-01

    Dodeca-2(E),4(E)-dienoic acid isobutylamide (DDI), an alkamide derived from the plant Echinacea purpurea, promotes adipocyte differentiation and activates peroxisome proliferator-activated receptor γ, which is associated with enhanced insulin sensitivity. In the present study, we investigated whether DDI may increase glucose uptake through activation of the insulin signaling pathway in 3T3-L1 adipocytes. DDI increased insulin-stimulated glucose uptake, and expression and translocation of glucose transporter 4 in adipocytes treated with sub-optimal levels of insulin. Additionally, DDI enhanced Akt phosphorylation, whereas phosphoinositide 3-kinase/Akt inhibitors suppressed DDI-induced glucose uptake. These results suggest that DDI may improve insulin sensitivity through the activation of Akt signaling, which leads to enhanced glucose uptake.

  7. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport.

    PubMed

    Walsh, M C; Rostagno, M H; Gardiner, G E; Sutton, A L; Richert, B T; Radcliffe, J S

    2012-08-01

    The objective of this study was to evaluate the effects of water-delivered, direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs after deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to 1 of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 10(9) cfu/L for each strain of bacteria; 3) control diet + organic acid-based blend (predominantly propionic, acetic, and benzoic acids) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg carbadox. Pigs were challenged with 10(10) cfu Salmonella enterica var Typhimurium 6 d after commencement of treatments. Pigs (n = 22/d) were harvested before Salmonella challenge and on d 2, 4, and 8 after challenge. Duodenal, jejunal, and ileal mucosal tissues were sampled for measurement of villus height and crypt depth. Jejunal tissue was sampled for determination of active nutrient absorption in modified Ussing chambers. Duodenal villus height was greater in pigs fed in-feed antibiotic before infection (P < 0.05). Jejunal crypts were deeper in DFM- and acid-treated pigs on d 4 after infection compared with all other treatments (P < 0.05). Salmonella infection resulted in a linear decrease in phosphorus (P < 0.001) and glucose (P < 0.05) active transport, and an increase (P < 0.001) in glutamine uptake immediately after challenge. Salmonella infection reduced basal short-circuit current (I(sc)); however, water-delivered DFM or organic acid treatments caused greater basal I(sc) on d 2 after challenge than did carbadox. Carbachol-induced chloride ion secretion was greatest in negative control pigs before infection (P < 0.01) and DFM-treated pigs (P < 0.05) after infection. In conclusion, both the DFM and acidification treatments induced increases in basal active ion movement and jejunal

  8. Nutrient Chemistry and Microbial Activity in the Upper Mississippi River Basin: Stoichiometry and Downstream Patterns

    EPA Science Inventory

    Nutrients, carbon, and silica have been used to track changes in water quality in the major rivers of the world. Most studies focus on the mouths of rivers and adjacent coastal waters. Studies on the Mississippi River have concluded that N enrichment and stable or declining Si co...

  9. Ovine maternal nutrient restriction from mid to late gestation decreases heptic progesterone inactivating enzyme activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously we have shown increased concentrations of progesterone and decreased liver weight in mid to late pregnant ewes provided a nutrient restricted vs. adequate diet. This alteration in peripheral progesterone could be due to increased synthesis and/or decreased clearance of progesterone. There...

  10. Estrogenic activity and nutrient losses in surface runoff after winter manure application to small watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confined Animal Feeding Operations generate large amounts of wastes that are land-applied to provide nutrients for crop production and return organic matter to the soil. Production practices and storage limitations often necessitate that wastes be applied to frozen and snow-covered soil. Under these...

  11. Strategy for nutrient control in modern effluent treatment plants.

    PubMed

    Sivard, A; Ericsson, T; Larsson, B

    2007-01-01

    The fate of nutrients in the modern effluent treatment plant depends on several factors, for example type of treatment plant, availability of nutrients in the specific effluent, dosing of nutrients and sludge age/production. New technologies with the aim to increase the efficiency and stability of the conventional activated sludge process have strongly affected the possibilities to control discharge of nutrients in pulp and paper effluents. A paradox is that a reduction of organic material may often lead to an increase of nutrient discharges. It is of the utmost importance that the operators have good knowledge of the factors affecting nutrient uptake and release in order to minimise nutrient discharge and obtain optimal plant performance. Dosing of nitrogen and phosphorus is one key factor in the sensitive balance in most pulp and paper effluent treatment plants. Correct dosing is crucial as high or low doses might lead not only to increased discharge of nutrients but also to severe operational problems with poor sludge quality, which in turn affects the plant performance for longer periods.

  12. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, S.; Iwanowicz, L.R.; Voshell, J.R.

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO 4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17??-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations >1ng/L. Relatively high concentrations of DIN (>1000??g/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R 2=0.56-0.81) and E2Eq (R 2=0.39-0.75). Relationships between watershed densities of AFOs and PO 4-P were weaker, but were also significant (R 2=0.27-0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO 4-P than streams without WWTP discharges, and PO 4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms. ?? 2011 Elsevier B.V.

  13. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, Serena; Iwanowicz, Luke R.; Voshell, J. Reese

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17β-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations > 1 ng/L. Relatively high concentrations of DIN (> 1000 μg/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R2 = 0.56–0.81) and E2Eq (R2 = 0.39–0.75). Relationships between watershed densities of AFOs and PO4-P were weaker, but were also significant (R2 = 0.27–0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO4-P than streams without WWTP discharges, and PO4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms.

  14. Effect of Solanum surattense on mitochondrial enzymes in diabetic rats and in vitro glucose uptake activity in L6 myotubes

    PubMed Central

    Sridevi, Muruhan; Kalaiarasi, Pannerselvam; Pugalendi, Kodukkur Viswanathan

    2015-01-01

    Background: S. surattense is widely used in Siddha medicine for various ailments. Objective: The aim was to evaluate the impact of alcoholic leaf-extract of S. surattense on mitochondrial enzymes in streptozotocin (STZ) induced diabetic rats and to study the in vitro muscle glucose uptake activity on L6 myotubes. Materials and Methods: The male albino Wistar rats were randomly divided into five groups of six animals each. Diabetes was induced by intraperitoneal injection of STZ (40 mg/kg body weight). After being confirmed the diabetic rats were treated with alcoholic leaf-extract of S. surattense (100 mg/kg body weight) for 45 days. The biochemical estimations (liver mitochondrial enzymes, antioxidants, thiobarbituric acid reactive substances [TBARS]) and histopathological studies were performed. Further, the in vitro muscle glucose uptake activity in L6 myotubes and messenger RNA (mRNA) expression of glucose transporter-4 (GLUT-4) was performed. Results: In diabetic rats, the activities of liver mitochondrial enzymes were found to be significantly lowered. The mitochondrial TBARS level increased, whereas the activities/level of enzymatic and non-enzymatic antioxidants decreased in diabetic rats. Administration of S. surattense to diabetic rats significantly reversed the above parameters toward normalcy. Furthermore in diabetic rats, the histopathological studies showed growth of adipose tissue and shrinkage of islets in the pancreas, liver showed fatty change with mild inflammation of portal triad, and kidney showed messangial capillary proliferation of glomeruli and fatty infiltration of tubules. Treatment with S. surattense brought back these changes to near normalcy. The extract was analyzed for in vitro muscle glucose uptake activity in L6 myotubes and mRNA expression of GLUT-4 by semi-quantitative reverse transcriptase-polymerase chain reaction. One nano gram per millilitre of S. surattense leaf-extract gave 115% glucose uptake on L6 myotubes. It also showed

  15. Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

    PubMed

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

  16. Cellular Uptakes, Biostabilities and Anti-miR-210 Activities of Chiral Arginine-PNAs in Leukaemic K562 Cells

    PubMed Central

    Manicardi, Alex; Fabbri, Enrica; Tedeschi, Tullia; Sforza, Stefano; Bianchi, Nicoletta; Brognara, Eleonora; Gambari, Roberto; Marchelli, Rosangela; Corradini, Roberto

    2012-01-01

    A series of 18-mer peptide nucleic acids (PNAs) targeted against micro-RNA miR-210 was synthesised and tested in a cellular system. Unmodified PNAs, R8-conjugated PNAs and modified PNAs containing eight arginine residues on the backbone, either as C2-modified (R) or C5-modified (S) monomers, all with the same sequence, were compared. Two different models were used for the modified PNAs: one with alternated chiral and achiral monomers and one with a stretch of chiral monomers at the N terminus. The melting temperatures of these derivatives were found to be extremely high and 5 m urea was used to assess differences between the different structures. FACS analysis and qRT-PCR on K562 chronic myelogenous leukaemic cells indicated that arginine-conjugated and backbone-modified PNAs display good cellular uptake, with best performances for the C2-modified series. Resistance to enzymatic degradation was found to be higher for the backbone-modified PNAs, thus enhancing the advantage of using these derivatives rather than conjugated PNAs in the cells in serum, and this effect is magnified in the presence of peptidases such as trypsin. Inhibition of miR-210 activity led to changes in the erythroid differentiation pathway, which were more evident in mithramycin-treated cells. Interestingly, the anti-miR activities differed with use of different PNAs, thus suggesting a role of the substituents not only in the cellular uptake, but also in the mechanism of miR recognition and inactivation. This is the first report relating to the use of backbone-modified PNAs as anti-miR agents. The results clearly indicate that backbone-modified PNAs are good candidates for the development of very efficient drugs based on anti-miR activity, due to their enhanced bioavailabilities, and that overall anti-miR performance is a combination of cellular uptake and RNA binding. PMID:22639449

  17. In vitro glucose uptake activity of Aegles marmelos and Syzygium cumini by activation of Glut-4, PI3 kinase and PPARgamma in L6 myotubes.

    PubMed

    Anandharajan, R; Jaiganesh, S; Shankernarayanan, N P; Viswakarma, R A; Balakrishnan, A

    2006-06-01

    The purpose of the present study is to investigate the effect of methanolic extracts of Aegles marmelos and Syzygium cumini on a battery of targets glucose transporter (Glut-4), peroxisome proliferator activator receptor gamma (PPARgamma) and phosphatidylinositol 3' kinase (PI3 kinase) involved in glucose transport. A. marmelos and S. cumini are anti-diabetic medicinal plants being used in Indian traditional medicine. Different solvent extracts extracted sequentially were analysed for glucose uptake activity at each step and methanol extracts were found to be significantly active at 100ng/ml dose comparable with insulin and rosiglitazone. Elevation of Glut-4, PPARgamma and PI3 kinase by A. marmelos and S. cumini in association with glucose transport supported the up-regulation of glucose uptake. The inhibitory effect of cycloheximide on A. marmelos- and S. cumini-mediated glucose uptake suggested that new protein synthesis is required for the elevated glucose transport. Current observation concludes that methanolic extracts of A. marmelos and S. cumini activate glucose transport in a PI3 kinase-dependent fashion.

  18. Methylglyoxal and carboxyethyllysine reduce glutamate uptake and S100B secretion in the hippocampus independently of RAGE activation.

    PubMed

    Hansen, Fernanda; Battú, Cíntia Eickhoff; Dutra, Márcio Ferreira; Galland, Fabiana; Lirio, Franciane; Broetto, Núbia; Nardin, Patrícia; Gonçalves, Carlos-Alberto

    2016-02-01

    Diabetes is a metabolic disease characterized by high fasting-glucose levels. Diabetic complications have been associated with hyperglycemia and high levels of reactive compounds, such as methylglyoxal (MG) and advanced glycation endproducts (AGEs) formation derived from glucose. Diabetic patients have a higher risk of developing neurodegenerative diseases, such as Alzheimer's disease or Parkinson's disease. Herein, we examined the effect of high glucose, MG and carboxyethyllysine (CEL), a MG-derived AGE of lysine, on oxidative, metabolic and astrocyte-specific parameters in acute hippocampal slices, and investigated some of the mechanisms that could mediate these effects. Glucose, MG and CEL did not alter reactive oxygen species (ROS) formation, glucose uptake or glutamine synthetase activity. However, glutamate uptake and S100B secretion were decreased after MG and CEL exposure. RAGE activation and glycation reactions, examined by aminoguanidine and L-lysine co-incubation, did not mediate these changes. Acute MG and CEL exposure, but not glucose, were able to induce similar effects on hippocampal slices, suggesting that conditions of high glucose concentrations are primarily toxic by elevating the rates of these glycation compounds, such as MG, and by generation of protein cross-links. Alterations in the secretion of S100B and the glutamatergic activity mediated by MG and AGEs can contribute to the brain dysfunction observed in diabetic patients.

  19. Methylphenidate Decreases ATP Levels and Impairs Glutamate Uptake and Na(+),K(+)-ATPase Activity in Juvenile Rat Hippocampus.

    PubMed

    Schmitz, Felipe; Pierozan, Paula; Rodrigues, André F; Biasibetti, Helena; Grings, Mateus; Zanotto, Bruna; Coelho, Daniella M; Vargas, Carmen R; Leipnitz, Guilhian; Wyse, Angela T S

    2016-11-14

    The study of the long-term neurological consequences of early exposure with methylphenidate (MPH) is very important since this psychostimulant has been widely misused by children and adolescents who do not meet full diagnostic criteria for ADHD. The aim of this study was to examine the effect of early chronic exposure with MPH on amino acids profile, glutamatergic and Na(+),K(+)-ATPase homeostasis, as well as redox and energy status in the hippocampus of juvenile rats. Wistar male rats received intraperitoneal injections of MPH (2.0 mg/kg) or saline solution (controls), once a day, from the 15th to the 45th day of age. Results showed that MPH altered amino acid profile in the hippocampus, decreasing glutamine levels. Glutamate uptake and Na(+),K(+)-ATPase activity were decreased after chronic MPH exposure in the hippocampus of rats. No changes were observed in the immunocontents of glutamate transporters (GLAST and GLT-1), and catalytic subunits of Na(+),K(+)-ATPase (α1, α2, and α3), as well as redox status. Moreover, MPH provoked a decrease in ATP levels in the hippocampus of chronically exposed rats, while citrate synthase, succinate dehydrogenase, respiratory chain complexes activities (II, II-III, and IV), as well as mitochondrial mass and mitochondrial membrane potential were not altered. Taken together, our results suggest that chronic MPH exposure at early age impairs glutamate uptake and Na(+),K(+)-ATPase activity probably by decreasing in ATP levels observed in rat hippocampus.

  20. Use of reference chemicals to determine passive uptake rates of common indoor air VOCs by collocation deployment of active and passive samplers.

    PubMed

    Xian, Qiming; Feng, Yong-Lai; Chan, Cecilia C; Zhu, Jiping

    2011-09-01

    Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity.

  1. A hypothesis on Microthrix parvicella proliferation in biological nutrient removal activated sludge systems with selector tanks.

    PubMed

    Noutsopoulos, Constantinos; Mamais, Daniel; Andreadakis, Andreas; Stams, Alfons

    2012-05-01

    The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between floc-forming microorganisms and M. parvicella for long-chain fatty acids uptake under aerobic, anoxic, and anaerobic conditions was formulated. According to this hypothesis, M. parvicella exhibits similar long-chain fatty acids uptake capacity with floc-forming microorganisms even at relatively high floc loading values that are very often imposed at selector tanks. Following this hypothesis, the failure of selector tanks to provide for an effective M. parvicella control is evidenced. Based on the experimental results, the ability of M. parvicella to utilize long-chain fatty acids with rates comparable to those of floc formers, even in anoxic conditions, in conjunction with its lower acetate utilization rates, provides a good explanation regarding its preference to slowly biodegradable organic carbon compounds.

  2. Influence of biologically-active substances on {sup 137}Cs and heavy metals uptake by Barley plant

    SciTech Connect

    Kruglov, Stanislav; Filipas, Alexander

    2007-07-01

    Available in abstract form only. Full text of publication follows: When solving the problem of contaminated agricultural lands rehabilitation, most of attention is concentrated on the effective means which allow the obtaining of ecologically safe production. The minimization of radionuclides and heavy metals (HM) content in farm products on the basis of their migration characteristics in agro-landscapes and with the regard for different factors influencing contaminants behavior in the soil-plant system is of great significance. Our investigation has shown that the effect of biologically active substances (BAS) using for seeds treatment on {sup 137}Cs transfer to barley grown on Cd contaminated soil was dependent on their properties and dosage, characteristics of soil contamination and biological peculiarities of plants, including stage of plants development. Seeds treatment by plant growth regulator Zircon resulted in a significant increase in {sup 137}Cs activity in harvest (40- 50%), increase in K concentration and significant reduction in Ca concentration. Increased Cd content in soil reduced {sup 137}Cs transfer to barley plants by 30-60% (p<0,05) and Zircon application further reduced its concentration. Ambiol and El also reduced {sup 137}Cs uptake by roots and Cd and Pb phyto-toxicity. The experimental data do not make it possible to link the BAS effect on inhibition of {sup 137}Cs absorption by plants directly with their influence on HM phyto-toxicity. The dependence of Concentration Ratio of {sup 137}Cs on the Ambiol and El dose was not proportional and the most significant decrease in the radionuclide uptake by plants was reported with the use of dose showing the most pronounced stimulating effect on the barley growth and development. The pre-sowing seed treatment with Ambiol increased Pb absorption by 35-50% and, on the contrary, decreased Cd uptake by plants by 30-40%. (authors)

  3. Enhanced Plant Nutrient use Efficiency with PGPR and AMF in an Integrated Nutrient Management System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-year field study was conducted with field corn from 2005 to 2007 to test the hypothesis that microbial inoculants that increase plant growth and yield will enhance nutrient uptake, and thereby remove more nutrients, especially N, P, and K from the field as part of an integrated nutrient mana...

  4. Relationships of biomass, nutrient pools and anthropogenic activities in Amazonian forests

    SciTech Connect

    Kauffman, J.B.; Cummings, D.L.; Rabbitt, R.E.; Ward, D.E. Forest Service, Missoula, MT )

    1993-06-01

    There are two general patterns associated with deforestation in Amazonia: shifting cultivation where forests are felled and burned every 4-10 years; and pasture conversion where burning occurs every 1-3 years. The former results in a more rapid rate of nutrient loss due to fire frequency and the greater susceptibility of aboveground nutrient pools to volatilization. Along the gradient from primary forest to burned degraded pasture or third-growth forest, aboveground biomass decreased from 434 Mg ha[sup [minus]1] to <8 Mg ha[sup [minus]1]. However, tremendous variability exists in the biomass, nutrient pools, and fire effects in Terra Firme forests, second-growth forests (Capoiera) and pastures. For example, N losses from primary forests ranged from 500 to 1380 kg ha[sup [minus]1], losses from Capoiera ranged from 300 to 400 kg ha[sup [minus]1] and losses from pastures were 200 to >500 kg ha[sup [minus]1]. Clearly these land use practices result in a significant transfer of C to the atmosphere, are not sustainable for human uses and may exacerbate difficulties in forest restoration.

  5. Boric acid and salinity effects on maize roots. Response of aquaporins ZmPIP1 and ZmPIP2, and plasma membrane H+-ATPase, in relation to water and nutrient uptake.

    PubMed

    Martinez-Ballesta, Maria del Carmen; Bastías, Elizabeth; Zhu, Chuanfeng; Schäffner, Anton R; González-Moro, Begoña; González-Murua, Carmen; Carvajal, Micaela

    2008-04-01

    Under saline conditions, an optimal cell water balance, possibly mediated by aquaporins, is important to maintain the whole-plant water status. Furthermore, excessive accumulation of boric acid in the soil solution can be observed in saline soils. In this work, the interaction between salinity and excess boron with respect to the root hydraulic conductance (L(0)), abundance of aquaporins (ZmPIP1 and ZmPIP2), ATPase activity and root sap nutrient content, in the highly boron- and salt-tolerant Zea mays L. cv. amylacea, was evaluated. A downregulation of root ZmPIP1 and ZmPIP2 aquaporin contents were observed in NaCl-treated plants in agreement with the L(0) measurements. However, in the H3BO3-treated plants differences in the ZmPIP1 and ZmPIP2 abundance were observed. The ATPase activity was related directly to the amount of ATPase protein and Na+ concentration in the roots, for which an increase in NaCl- and H3BO3+ NaCl-treated plants was observed with respect to untreated and H3BO3-treated plants. Although nutrient imbalance may result from the effect of salinity or H3BO3 alone, an ameliorative effect was observed when both treatments were applied together. In conclusion, our results suggest that under salt stress, the activity of specific membrane components can be influenced directly by boric acid, regulating the functions of certain aquaporin isoforms and ATPase as possible components of the salinity tolerance mechanism.

  6. Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth.

    PubMed

    Breton, Jonathan; Tennoune, Naouel; Lucas, Nicolas; Francois, Marie; Legrand, Romain; Jacquemot, Justine; Goichon, Alexis; Guérin, Charlène; Peltier, Johann; Pestel-Caron, Martine; Chan, Philippe; Vaudry, David; do Rego, Jean-Claude; Liénard, Fabienne; Pénicaud, Luc; Fioramonti, Xavier; Ebenezer, Ivor S; Hökfelt, Tomas; Déchelotte, Pierre; Fetissov, Sergueï O

    2016-02-09

    The composition of gut microbiota has been associated with host metabolic phenotypes, but it is not known if gut bacteria may influence host appetite. Here we show that regular nutrient provision stabilizes exponential growth of E. coli, with the stationary phase occurring 20 min after nutrient supply accompanied by bacterial proteome changes, suggesting involvement of bacterial proteins in host satiety. Indeed, intestinal infusions of E. coli stationary phase proteins increased plasma PYY and their intraperitoneal injections suppressed acutely food intake and activated c-Fos in hypothalamic POMC neurons, while their repeated administrations reduced meal size. ClpB, a bacterial protein mimetic of α-MSH, was upregulated in the E. coli stationary phase, was detected in plasma proportional to ClpB DNA in feces, and stimulated firing rate of hypothalamic POMC neurons. Thus, these data show that bacterial proteins produced after nutrient-induced E. coli growth may signal meal termination. Furthermore, continuous exposure to E. coli proteins may influence long-term meal pattern.

  7. Impacts of human activities on nutrient transport in the Yellow River: The role of the Water-Sediment Regulation Scheme.

    PubMed

    Li, Xinyu; Chen, Hontao; Jiang, Xueyan; Yu, Zhigang; Yao, Qingzhen

    2017-03-15

    Anthropogenic activities alter the natural states of large rivers and their surrounding environment. The Yellow River is a well-studied case of a large river with heavy human control. An artificial managed water and sediment release system, known as the Water-Sediment Regulation Scheme (WSRS), has been carried out annually in the Yellow River since 2002. Nutrient concentrations and composition display significant time and space variations during the WSRS period. To figure out the anthropogenic impact of nutrient changes and transport in the Yellow River, biogeochemical observations were carried out in both middle reaches and lower reaches of the Yellow River during 2014 WSRS period. WSRS has a direct impact on water oxidation-reduction environment in the middle reaches; concentrations of nitrite (NO2(-)) and ammonium (NH4(+)) increased, while nitrate (NO3(-)) concentration decreased by enhanced denitrification. WSRS changed transport of water and sediment; dissolved silicate (DSi) in the middle reaches was directly controlled by sediments release during the WSRS while in the lower reaches, DSi changed with both sediments and water released from middle reaches. During the WSRS, the differences of nutrient fluxes and concentrations between lower reaches and middle reaches were significant; dissolved inorganic phosphorous (DIP) and dissolved inorganic nitrogen (DIN) were higher in low reaches because of anthropogenic inputs. Human intervention, especially WSRS, can apparently change the natural states of both the mainstream and estuarine environments of the Yellow River within a short time.

  8. Noscapine chemosensitization enhances docetaxel anticancer activity and nanocarrier uptake in triple negative breast cancer

    PubMed Central

    Doddapaneni, Ravi; Patel, Ketan; Chowdhury, Nusrat; Singh, Mandip

    2016-01-01

    Chemosensitization and enhanced delivery to solid tumor are widely explored strategies to augment the anticancer efficacy of existing chemotherapeutics agents. The aim of current research was to investigate the role of low dose Noscapine (Nos) in potentiating docetaxel cytotoxicity and enhancing tumor penetration of nanocarriers. The objectives are; (1) To evaluate the chemo-sensitizing effect of Nos in combination with docetaxel (DTX), and to elucidate the possible mechanism (2) To investigate the effect of low dose Nos on tumor stroma and enhancing nanocarrier uptake in triple negative breast cancer (TNBC) bearing nude mice. Cytotoxicity and flow cytometry analysis of DTX in Nos (4 µM) pre-treated MDA-MB-231 cells showed 3.0-fold increase in cell killing and 30% increase in number of late apoptotic cells, respectively. Stress transducer p38 phosphorylation was significantly upregulated with Nos exposure. DTX showed remarkable downregulation in expression of bcl-2, survivin and pAKT in Nos pre-treated MDA-MB-231 cells. Nos pre-sensitization significantly (p < 0.02) enhanced the anti-migration effect of DTX. In vivo studies in orthotopic TNBC tumor bearing mice showed marked reduction in tumor collagen-I levels and significantly (p < 0.03) higher intra-tumoral uptake of coumarin-6 loaded PEGylated liposomes (7-fold) in Nos treated group. Chemo-sensitization and anti-fibrotic effect of Nos could be a promising approach to increase anticancer efficacy of DTX which can be used for other nanomedicinal products. PMID:27177833

  9. Effect of leukotriene C4 on electromechanical activity and Ca/sup 2 +/ uptake in taenia coli

    SciTech Connect

    Zschauer, A.; Matthews, E.K.; Richardson, B.P.

    1988-10-01

    The actions of leukotriene C4 (LTC4) on electromechanical activity and /sup 45/Ca/sup 2 +/ uptake in guinea pig taenia coli were investigated. The contractile action of LTC4 was abolished by the removal of extracellular Ca/sup 2 +/. LTC4 concentrations eliciting a maximal contraction in normal medium produced no response in preparations depolarized with KCl. In single sucrose gap studies, LTC4 increased both the frequency of electrical spiking and tension. These effects were blocked by the dihydropyridine Ca/sup 2 +/-channel antagonist PY 108-068 and by the leukotriene receptor antagonist FPL 55712. In double sucrose gap experiments, LTC4 caused a small depolarization without measurable change in membrane conductivity; increased spontaneous electrical activity was again accompanied by an increase in tension. LTC4 caused a detectable increase in /sup 45/Ca/sup 2 +/ uptake only at extracellular Ca/sup 2 +/ concentrations less than 1 mM, and this was again inhibited by PY 108-068 or FPL 55712. It is concluded that the contractile effects of LTC4 in guinea pig taenia coli occur as a consequence of its ability to open voltage-sensitive Ca/sup 2 +/ channels, an effect that may occur independently of membrane depolarization.

  10. Interactions between temperature and nutrients across levels of ecological organization.

    PubMed

    Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

    2015-03-01

    Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and

  11. Structure-activity relations of leucine derivatives reveal critical moieties for cellular uptake and activation of mTORC1-mediated signaling.

    PubMed

    Nagamori, Shushi; Wiriyasermkul, Pattama; Okuda, Suguru; Kojima, Naoto; Hari, Yoshiyuki; Kiyonaka, Shigeki; Mori, Yasuo; Tominaga, Hideyuki; Ohgaki, Ryuichi; Kanai, Yoshikatsu

    2016-04-01

    Among amino acids, leucine is a potential signaling molecule to regulate cell growth and metabolism by activating mechanistic target of rapamycin complex 1 (mTORC1). To reveal the critical structures of leucine molecule to activate mTORC1, we examined the structure-activity relationships of leucine derivatives in HeLa S3 cells for cellular uptake and for the induction of phosphorylation of p70 ribosomal S6 kinase 1 (p70S6K), a downstream effector of mTORC1. The activation of mTORC1 by leucine and its derivatives was the consequence of two successive events: the cellular uptake by L-type amino acid transporter 1 (LAT1) responsible for leucine uptake in HeLa S3 cells and the activation of mTORC1 following the transport. The structural requirement for the recognition by LAT1 was to have carbonyl oxygen, alkoxy oxygen of carboxyl group, amino group and hydrophobic side chain. In contrast, the requirement for mTORC1 activation was more rigorous. It additionally required fixed distance between carbonyl oxygen and alkoxy oxygen of carboxyl group, and amino group positioned at α-carbon. L-Configuration in chirality and appropriate length of side chain with a terminal isopropyl group were also important. This confirmed that LAT1 itself is not a leucine sensor. Some specialized leucine sensing mechanism with rigorous requirement for agonistic structures should exist inside the cells because leucine derivatives not transported by LAT1 did not activate mTORC1. Because LAT1-mTOR axis is involved in the regulation of cell growth and cancer progression, the results from this study may provide a new insight into therapeutics targeting both LAT1 and leucine sensor.

  12. Uncoupling of attenuated myo-(3H)inositol uptake and dysfunction in Na(+)-K(+)-ATPase pumping activity in hypergalactosemic cultured bovine lens epithelial cells

    SciTech Connect

    Cammarata, P.R.; Tse, D.; Yorio, T. )

    1991-06-01

    Attenuation of both the active transport of myo-inositol and Na(+)-K(+)-ATPase pumping activity has been implicated in the onset of sugar cataract and other diabetic complications in cell culture and animal models of the disease. Cultured bovine lens epithelial cells (BLECs) maintained in galactose-free Eagle's minimal essential medium (MEM) or 40 mM galactose with and without sorbinil for up to 5 days were examined to determine the temporal effects of hypergalactosemia on Na(+)-K(+)-ATPase and myo-inositol uptake. The Na(+)-K(+)-ATPase pumping activity after 5 days of continuous exposure to galactose did not change, as demonstrated by 86Rb uptake. The uptake of myo-(3H)inositol was lowered after 20 h of incubation in galactose and remained below that of the control throughout the 5-day exposure period. The coadministration of sorbinil to the galactose medium normalized the myo-(3H)inositol uptake. No significant difference in the rates of passive efflux of myo-(3H)inositol or 86Rb from preloaded galactose-treated and control cultures was observed. Culture-media reversal studies were also carried out to determine whether the galactose-induced dysfunction in myo-inositol uptake could be corrected. BLECs were incubated in galactose for 5 days, then changed to galactose-free physiological medium with and without sorbinil for a 1-day recovery period. myo-Inositol uptake was reduced to 34% of control after 6 days of continuous exposure to galactose. Within 24 h of media reversal, myo-inositol uptake returned to or exceeded control values in BLECs switched to either MEM or MEM with sorbinil.2+ reversible and occurred independently of changes in Na(+)-K(+)-ATPase pumping activity in cultured lens epithelium, indicating that the two parameters are not strictly associated and that the deficit in myo-inositol uptake occurs rapidly during hypergalactosemia.

  13. The inability of phosphatidylinositol 3-kinase activation to stimulate GLUT4 translocation indicates additional signaling pathways are required for insulin-stimulated glucose uptake.

    PubMed

    Isakoff, S J; Taha, C; Rose, E; Marcusohn, J; Klip, A; Skolnik, E Y

    1995-10-24

    Recent experimental evidence has focused attention to the role of two molecules, insulin receptor substrate 1 (IRS-1) and phosphatidylinositol 3-kinase (PI3-kinase), in linking the insulin receptor to glucose uptake; IRS-1 knockout mice are insulin resistant, and pharmacological inhibitors of PI3-kinase block insulin-stimulated glucose uptake. To investigate the role of PI3-kinase and IRS-1 in insulin-stimulated glucose uptake we examined whether stimulation of insulin-sensitive cells with platelet-derived growth factor (PDGF) or with interleukin 4 (IL-4) stimulates glucose uptake; the activated PDGF receptor (PDGFR) directly binds and activates PI3-kinase, whereas the IL-4 receptor (IL-4R) activates PI3-kinase via IRS-1 or the IRS-1-related molecule 4PS. We found that stimulation of 3T3-L1 adipocytes with PDGF resulted in tyrosine phosphorylation of the PDGFR and activation of PI3-kinase in these cells. To examine whether IL-4 stimulates glucose uptake, L6 myoblasts were engineered to overexpress GLUT4 as well as both chains of the IL-4R (L6/IL-4R/GLUT4); when these L6/IL-4R/GLUT4 myoblasts were stimulated with IL-4, IRS-1 became tyrosine phosphorylated and associated with PI3-kinase. Although PDGF and IL-4 can activate PI3-kinase in the respective cell lines, they do not possess insulin's ability to stimulate glucose uptake and GLUT4 translocation to the plasma membrane. These findings indicate that activation of PI3-kinase is not sufficient to stimulate GLUT4 translocation to the plasma membrane. We postulate that activation of a second signaling pathway by insulin, distinct from PI3-kinase, is necessary for the stimulation of glucose uptake in insulin-sensitive cells.

  14. Soil Microbial and Enzymatic Responses to Complex and Labile Nutrient Inputs

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Vitousek, P. M.

    2003-12-01

    Microbial extracellular enzymes are essential for converting complex organic compounds into smaller molecules that are available for plant and microbial uptake. However, enzyme production represents a substantial resource cost for microbes, and microbes may be under selection to produce enzymes only when benefits exceed costs. We predicted that soil enzyme activities would be highest when complex substrates were abundant, but available nutrients were scarce (large potential benefit from enzyme production). We also predicted that rates of nutrient and carbon mineralization would correspond to observed shifts in enzyme activities. To test these predictions, we added insoluble and available carbon, nitrogen, and phosphorus substrates to soil incubations and measured enzyme activities, CO2 respiration, microbial biomass, and nutrient mineralization. Labile carbon additions increased respiration rates and microbial biomass, while labile nutrient additions were taken up by microbes but did not increase respiration rates. Labile carbon + nitrogen additions increased acid phosphatase activity, while labile nitrogen additions suppressed aminopeptidase activity. Insoluble nutrients caused major increases in enzyme and microbial activities only when added in combination with complementary labile nutrients (e.g. insoluble carbon + available nitrogen and phosphorus). These results indicate that microbes respond to soil nutrient status by changing patterns of extracellular enzyme production. Such changes can allow microbes to access nutrients in complex molecules, but may be limited by the availability of resources to build enzymes.

  15. Cellular Uptake and Ultrastructural Localization Underlie the Pro-apoptotic Activity of a Hydrocarbon-stapled BIM BH3 Peptide.

    PubMed

    Edwards, Amanda L; Wachter, Franziska; Lammert, Margaret; Huhn, Annissa J; Luccarelli, James; Bird, Gregory H; Walensky, Loren D

    2015-09-18

    Hydrocarbon stapling has been applied to restore and stabilize the α-helical structure of bioactive peptides for biochemical, structural, cellular, and in vivo studies. The peptide sequence, in addition to the composition and location of the installed staple, can dramatically influence the properties of stapled peptides. As a result, constructs that appear similar can have distinct functions and utilities. Here, we perform a side-by-side comparison of stapled peptides modeled after the pro-apoptotic BIM BH3 helix to highlight these principles. We confirm that replacing a salt-bridge with an i, i + 4 hydrocarbon staple does not impair target binding affinity and instead can yield a biologically and pharmacologically enhanced α-helical peptide ligand. Importantly, we demonstrate by electron microscopy that the pro-apoptotic activity of a stapled BIM BH3 helix correlates with its capacity to achieve cellular uptake without membrane disruption and accumulate at the organellar site of mechanistic activity.

  16. OsPT2, a phosphate transporter, is involved in the active uptake of selenite in rice.

    PubMed

    Zhang, Lianhe; Hu, Bin; Li, Wei; Che, Ronghui; Deng, Kun; Li, Hua; Yu, Feiyan; Ling, Hongqing; Li, Youjun; Chu, Chengcai

    2014-03-01

    • Selenite is a predominant form of selenium (Se) available to plants, especially in anaerobic soils, but the molecular mechanism of selenite uptake by plants is not well understood. • ltn1, a rice mutant previously shown to have increased phosphate (Pi) uptake, was found to exhibit higher selenite uptake than the wild-type in both concentration- and time-dependent selenite uptake assays. Respiratory inhibitors significantly inhibited selenite uptake in the wildtype and the ltn1 mutant, indicating that selenite uptake was coupled with H(+) and energy-dependent. Selenite uptake was greatly enhanced under Pi-starvation conditions, suggesting that Pi transporters are involved in selenite uptake. • OsPT2, the most abundantly expressed Pi transporter in the roots, is also significantly up-regulated in ltn1 and dramatically induced by Pi starvation. OsPT2-overexpressing and knockdown plants displayed significantly increased and decreased rates of selenite uptake, respectively, suggesting that OsPT2 plays a crucial role in selenite uptake. Se content in rice grains also increased significantly in OsPT2-overexpressing plants. • These data strongly demonstrate that selenite and Pi share similar uptake mechanisms and that OsPT2 is involved in selenite uptake, which provides a potential strategy for breeding Se-enriched rice varieties.

  17. Mechanisms of nutrient sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The term nutrient sensing has emerged to describe the molecular mechanisms by which nutrients and their metabolites interact with various cell surface receptors, intracellular signaling proteins, and nuclear receptors and modulate the activity of a complex network of signaling pathways that regulate...

  18. Litter type affects the activity of aerobic decomposers in a boreal peatland more than site nutrient and water table regimes

    NASA Astrophysics Data System (ADS)

    Straková, P.; Niemi, R. M.; Freeman, C.; Peltoniemi, K.; Toberman, H.; Heiskanen, I.; Fritze, H.; Laiho, R.

    2011-09-01

    Peatlands are carbon (C) storage ecosystems sustained by a high water table (WT). High WT creates anoxic conditions that suppress the activity of aerobic decomposers and provide conditions for peat accumulation. Peatland function can be dramatically affected by WT drawdown caused by climate and/or land-use change. Aerobic decomposers are directly affected by WT drawdown through environmental factors such as increased oxygenation and nutrient availability. Additionally, they are indirectly affected via changes in plant community composition and litter quality. We studied the relative importance of direct and indirect effects of WT drawdown on aerobic decomposer activity in plant litter at two stages of decomposition (incubated in the field for 1 or 2 years). We did this by profiling 11 extracellular enzymes involved in the mineralization of organic C, nitrogen (N), phosphorus (P) and sulphur. Our study sites represented a three-stage chronosequence from pristine to short-term (years) and long-term (decades) WT drawdown conditions under two nutrient regimes (bog and fen). The litter types included reflected the prevalent vegetation: Sphagnum mosses, graminoids, shrubs and trees. Litter type was the main factor shaping microbial activity patterns and explained about 30 % of the variation in enzyme activities and activity allocation. Overall, enzyme activities were higher in vascular plant litters compared to Sphagnum litters, and the allocation of enzyme activities towards C or nutrient acquisition was related to the initial litter quality (chemical composition). Direct effects of WT regime, site nutrient regime and litter decomposition stage (length of incubation period) summed to only about 40 % of the litter type effect. WT regime alone explained about 5 % of the variation in enzyme activities and activity allocation. Generally, enzyme activity increased following the long-term WT drawdown and the activity allocation turned from P and N acquisition towards C

  19. Uptake of poly-dispersed single-walled carbon nanotubes and decline of functions in mouse NK cells undergoing activation.

    PubMed

    Alam, Anwar; Puri, Niti; Saxena, Rajiv K

    2016-09-01

    The interaction of poly-dispersed acid-functionalized single-walled carbon nanotubes (AF-SWCNT) with NK cells undergoing activation was examined. Exposure to AF-SWCNT during NK activation in vitro by interleukin (IL)-2, and in vivo by Poly(I:C) significantly lowered cytotoxic activity generated against YAC-1 tumor cells. Recoveries of spleen NK1.1(+) cells as well as the activated subset of NK cells (NK1.1(+)CD69(+) cells) were significantly reduced by the AF-SWCNT exposure. The proportion of apoptotic NK cells (NK1.1(+) phosphatidylserine(+)) in the spleen cell preparations activated in vitro was also significantly elevated. Expression levels of CD107a [for assessing NK cell degranulation] as well as of FasL marker [mediating non-secretory pathway of NK cell killing] were significantly lower in cells exposed to AF-SWCNT during the activation phase. Intracellular levels of interferon (IFN)-γ and tumor necrosis factor (TNF)-α in the cells were also significantly reduced. Fluorescent AF-SWCNT (FAF-SWCNT) were internalized by the NK cells and uptake was significantly greater in activated cells. Confocal microscopy indicated the internalized FAF-SWCNT were localized to the cytoplasm of the NK cells. These results indicated that AF-SWCNT were internalized by NK cells and caused a general down-regulation of a variety of parameters associated with NK cell cytotoxicity and other cellular functions.

  20. The relationship between skeletal muscle mitochondrial citrate synthase activity and whole body oxygen uptake adaptations in response to exercise training

    PubMed Central

    Vigelsø, Andreas; Andersen, Nynne B; Dela, Flemming

    2014-01-01

    Citrate synthase (CS) activity is a validated biomarker for mitochondrial density in skeletal muscle. CS activity is also used as a biochemical marker of the skeletal muscle oxidative adaptation to a training intervention, and a relationship between changes in whole body aerobic capacity and changes in CS activity is often assumed. However, this relationship and absolute values of CS and maximal oxygen uptake (V.O2max) has never been assessed across different studies. A systematic PubMed search on literature published from 1983 to 2013 was performed. The search profile included: citrate, synthase, human, skeletal, muscle, training, not electrical stimulation, not in-vitro, not rats. Studies that reported changes in CS activity and V.O2max were included. Different training types and subject populations were analyzed independently to assess correlation between relative changes in V.O2max and CS activity. 70 publications with 97 intervention groups were included. There was a positive (r = 0.45) correlation (P < 0.001) between the relative change in V.O2max and the relative change in CS activity. All reported absolute values of CS and V.O2max did not correlate (r =- 0.07, n = 148, P = 0.4). Training induced changes in whole body oxidative capacity is matched by changes in muscle CS activity in a nearly 1:1 relationship. Absolute values of CS across different studies cannot be compared unless a standardized analytical method is used by all laboratories. PMID:25057335

  1. Oxygen Uptake and Hydrogen-Stimulated Nitrogenase Activity from Azorhizobium caulinodans ORS571 Grown in a Succinate-Limited Chemostat

    PubMed Central

    Allen, George C.; Grimm, Daniel T.; Elkan, Gerald H.

    1991-01-01

    Succinate-limited continuous cultures of an Azorhizobium caulinodans strain were grown on ammonia or nitrogen gas as a nitrogen source. Ammonia-grown cells became oxygen limited at 1.7 μM dissolved oxygen, whereas nitrogen-fixing cells remained succinate limited even at dissolved oxygen concentrations as low as 0.9 μM. Nitrogen-fixing cells tolerated dissolved oxygen concentrations as high as 41 μM. Succinate-dependent oxygen uptake rates of cells from the different steady states ranged from 178 to 236 nmol min−1 mg of protein−1 and were not affected by varying chemostat-dissolved oxygen concentration or nitrogen source. When equimolar concentrations of succinate and β-hydroxybutyrate were combined, oxygen uptake rates were greater than when either substrate was used alone. Azide could also used alone as a respiratory substrate regardless of nitrogen source; however, when azide was added following succinate additions, oxygen uptake was inhibited in ammonia-grown cells and stimulated in nitrogen-fixing cells. Use of 25 mM succinate in the chemostat resevoir at a dilution rate of 0.1 h−1 resulted in high levels of background respiration and nitrogenase activity, indicating that the cells were not energy limited. Lowering the reservoir succinate to 5 mM imposed energy limitation. Maximum succinate-dependent nitrogenase activity was 1,741 nmol of C2H4h−1 mg (dry weight)−1, and maximum hydrogen-dependent nitrogenase activity was 949 nmol of C2H4 h−1 mg (dry weight)−1. However, when concentration of 5% (vol/vol) hydrogen or greater were combined with succinate, nitrogenase activity decreased by 35% in comparison to when succinate was used alone. Substitution of argon for nitrogen in the chemostat inflow gas resulted in “washout,” proving that ORS571 can grow on N2 and that there was not a nitrogen source in the medium that could substitute. PMID:16348585

  2. Histamine H3 receptor activation inhibits dopamine synthesis but not release or uptake in rat nucleus accumbens.

    PubMed

    Aquino-Miranda, Guillermo; Escamilla-Sánchez, Juan; González-Pantoja, Raúl; Bueno-Nava, Antonio; Arias-Montaño, José-Antonio

    2016-07-01

    We studied the effect of activating histamine H3 receptors (H3Rs) on rat nucleus accumbens (rNAcc) dopaminergic transmission by analyzing [(3)H]-dopamine uptake by synaptosomes, and dopamine synthesis and depolarization-evoked [(3)H]-dopamine release in slices. The uptake of [(3)H]-dopamine by rNAcc synaptosomes was not affected by the H3R agonist RAMH (10(-10)-10(-6) M). In rNAcc slices perfusion with RAMH (1 μM) had no significant effect on [(3)H]-dopamine release evoked by depolarization with 30 mM K(+) (91.4 ± 4.5% of controls). The blockade of dopamine D2 autoreceptors with sulpiride (1 μM) enhanced K(+)-evoked [(3)H]-dopamine release (168.8 ± 15.5% of controls), but under this condition RAMH (1 μM) also failed to affect [(3)H]-dopamine release. Dopamine synthesis was evaluated in rNAcc slices incubated with the l-dihydroxyphenylalanine (DOPA) decarboxylase inhibitor NSD-1015 (1 mM). Forskolin-induced DOPA accumulation (220.1 ± 10.4% of controls) was significantly reduced by RAMH (41.1 ± 6.5% and 43.5 ± 9.1% inhibition at 100 nM and 1 μM, respectively), and this effect was prevented by the H3R antagonist ciproxifan (10 μM). DOPA accumulation induced by preventing cAMP degradation with IBMX (iso-butyl-methylxantine, 1 mM) or by activating receptors for the vasoactive intestinal peptide (VIP)/pituitary adenylate cyclase-activating peptide (PACAP) with PACAP-27 (1 μM) was reduced (IBMX) or prevented (PACAP-27) by RAMH (100 nM). In contrast, DOPA accumulation induced by 8-Bromo-cAMP (1 mM) was not affected by RAMH (100 nM). These results indicate that in rNAcc H3Rs do not modulate dopamine uptake or release, but regulate dopamine synthesis by inhibiting cAMP formation and thus PKA activation. This article is part of the Special Issue entitled 'Histamine Receptors'.

  3. Effects of Atrazine, Metolachlor, Carbaryl and Chlorothalonil on Benthic Microbes and Their Nutrient Dynamics

    PubMed Central

    Elias, Daniel; Bernot, Melody J.

    2014-01-01

    Atrazine, metolachlor, carbaryl, and chlorothalonil are detected in streams throughout the U.S. at concentrations that may have adverse effects on benthic microbes. Sediment samples were exposed to these pesticides to quantify responses of ammonium, nitrate, and phosphate uptake by the benthic microbial community. Control uptake rates of sediments had net remineralization of nitrate (−1.58 NO3 µg gdm−1 h−1), and net assimilation of phosphate (1.34 PO4 µg gdm−1 h−1) and ammonium (0.03 NH4 µg gdm−1 h−1). Metolachlor decreased ammonium and phosphate uptake. Chlorothalonil decreased nitrate remineralization and phosphate uptake. Nitrate, ammonium, and phosphate uptake rates are more pronounced in the presence of these pesticides due to microbial adaptations to toxicants. Our interpretation of pesticide availability based on their water/solid affinities supports no effects for atrazine and carbaryl, decreasing nitrate remineralization, and phosphate assimilation in response to chlorothalonil. Further, decreased ammonium and phosphate uptake in response to metolachlor is likely due to affinity. Because atrazine target autotrophs, and carbaryl synaptic activity, effects on benthic microbes were not hypothesized, consistent with results. Metolachlor and chlorothalonil (non-specific modes of action) had significant effects on sediment microbial nutrient dynamics. Thus, pesticides with a higher affinity to sediments and/or broad modes of action are likely to affect sediment microbes' nutrient dynamics than pesticides dissolved in water or specific modes of action. Predicted nutrient uptake rates were calculated at mean and peak concentrations of metolachlor and chlorothalonil in freshwaters using polynomial equations generated in this experiment. We concluded that in natural ecosystems, peak chlorothalonil and metolachlor concentrations could affect phosphate and ammonium by decreasing net assimilation, and nitrate uptake rates by decreasing remineralization

  4. Extraction of nutrients from foam in a membrane activated sludge system.

    PubMed

    Lo, K V; Chan, W I; Lo, I W; Koch, F; Liao, P H

    2010-10-01

    This study investigated the feasibility of treating the foams generated in enhanced biological phosphorus removal processes with the microwave-enhanced advanced oxidation process to reduce solids and solubilize nutrients for recovery purposes. It was found that more than half of the total chemical oxygen demand was solubilized during the treatment with just a small dose of hydrogen peroxide, signifying effective destruction of foam solids. Significant solubilization of phosphates, volatile fatty acids and ammonia was also observed, along with the release of metals contained in the foam, including calcium, potassium, and magnesium, which thereby represents additional potential benefits for nutrient recovery via subsequent crystallization processes. Since the solids content of foam is typically high, pretreatment for thickening sludge solids is not necessary prior to the use of microwave-enhanced advanced oxidation processes. As a result, this also offers further potential for reduction of energy costs. The process could be an efficient method for the removal and control of foam and the recovery of all available phosphorus at the same time.

  5. Protozoan biomass relation to nutrient and chemical oxygen demand removal in activated sludge mixed liquor.

    PubMed

    Akpor, Oghenerobor B; Momba, Maggy N B; Okonkwo, Jonathan O

    2008-08-01

    The relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass concentrations (10(1), 10(2) and 10(3) cells/mL). The study was carried out in a shaking flask environment at a shaking speed of 100 rpm for 96 h at 25 degrees C. Aliquot samples were taken periodically for the determination of phosphate, nitrate, COD and dissolved oxygen, using standard methods. The results revealed remarkable phosphate removal of 82-95% at biomass concentration of 10(3)cells/mL. A high nitrate removal of over 87% was observed at all initial biomass concentration in mixed liquor. There was an observed COD increase of over 50% in mixed liquor in at the end of 96-h incubation and this was irrespective of initial biomass concentration used for inoculation. The study shows the trend in nutrient and COD removal at different biomass concentrations of the test isolates in mixed liquor.

  6. Role of active floodplains for nutrient retention in the river Rhine.

    PubMed

    Olde Venterink, H; Wiegman, F; Van der Lee, G E M; Vermaat, J E

    2003-01-01

    We evaluated the importance of floodplains for nutrient retention in two distributaries of the river Rhine (Waal and IJssel) by monitoring N and P retention in a body of water during downstream transport. We hypothesized that (i) retention of P is much larger than retention of N and (ii) nutrient retention increases with an increasing amount of the discharge flowing through floodplains (QF). The second hypothesis was tested by comparing retention between the rivers Waal (low QF) and IJssel (high QF), as well as at different discharges. Total nitrogen (TN) did not decrease significantly during downstream transport in both rivers, whereas 20 to 45% of total phosphorus (TP) disappeared during transport in the river IJssel. This difference between N and P retention-supporting the first hypothesis-was probably caused by differences in sedimentation through a much lower proportion of N adsorbed to particles than of P (2-3% of N vs. 50-70% of P). Phosphorus retention was only observed in the IJssel and not in the Waal, and absolute P retention (g P s(-1) km(-1)) in the IJssel increased with increasing QF. The second hypothesis was, nevertheless, not fully supported, because the percentage P retention (% of P load) decreased (instead of increased) with increasing QF. The percentage P retention increased with decreasing river depth and flow velocity; it seemed related to the efficiency of sediment trapping.

  7. Diffusion Limitation of Oxygen Uptake and Nitrogenase Activity in the Root Nodules of Parasponia rigida Merr. and Perry 1

    PubMed Central

    Tjepkema, John D.; Cartica, Robert J.

    1982-01-01

    Parasponia is the first non-legume genus proven to form nitrogen-fixing root nodules induced by rhizobia. Infiltration with India ink demonstrated that intercellular air spaces are lacking in the inner layers of the nodule cortex. Oxygen must diffuse through these layers to reach the cells containing the rhizobia, and it was calculated that most of the gradient in O2 partial pressure between the atmosphere and rhizobia occurs at the inner cortex. This was confirmed by O2 microelectrode measurements which showed that the O2 partial pressure was much lower in the zone of infected cells than in the cortex. Measurements of nitrogenase activity and O2 uptake as a function of temperature and partial pressure of O2 were consistent with diffusion limitation of O2 uptake by the inner cortex. In spite of the presumed absence of leghemoglobin in nodules of Parasponia rigida Merr. and Perry, energy usage for nitrogen fixation was similar to that in legume nodules. The results demonstrate that O2 regulation in legume and Parasponia nodules is very similar and differs from O2 regulation in actionorhizal nodules. Images PMID:16662284

  8. Measurement of gas/water uptake coefficients for trace gases active in the marine environment

    SciTech Connect

    Davidovits, P. . Dept. of Chemistry); Worsnop, D.W.; Zahniser, M.S.; Kolb, C.E. . Center for Chemical and Environmental Physics)

    1992-02-01

    Ocean produced reduced sulfur compounds including dimethylsulfide (DMS), hydrogen sulfide (H{sub 2}S), carbon disulfide (CS{sub 2}), methyl mercaptan (CH{sub 3}CH) and carbonyl sulfide (OCS) deliver a sulfur burden to the atmosphere which is roughly equal to sulfur oxides produced by fossil fuel combustion. These species and their oxidation products dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO{sub 2}) and methane sulfonic acid (MSA) dominate aerosol and CCN production in clean marine air. Furthermore, oxidation of reduced sulfur species will be strongly influenced by NO{sub x}/O{sub 3} chemistry in marine atmospheres. The multiphase chemical processes for these species must be understood in order to study the evolving role of combustion produced sulfur oxides over the oceans. We have measured the chemical and physical parameters affecting the uptake of reduced sulfur compounds, their oxidation products, ozone, and nitrogen oxides by the ocean's surface, and marine clouds, fogs, and aerosols. These parameters include: gas/surface mass accommodation coefficients; physical and chemically modified (effective) Henry's law constants; and surface and liquid phase reaction constants. These parameters are critical to understanding both the interaction of gaseous trace species with cloud and fog droplets and the deposition of trace gaseous species to dew covered, fresh water and marine surfaces.

  9. Human biliverdin reductase-based peptides activate and inhibit glucose uptake through direct interaction with the kinase domain of insulin receptor

    PubMed Central

    Gibbs, Peter E. M.; Lerner-Marmarosh, Nicole; Poulin, Amelia; Farah, Elie; Maines, Mahin D.

    2014-01-01

    Insulin binding changes conformation of the insulin receptor kinase (IRK) domain and initiates glucose uptake through the insulin, IGF-1, phosphatidyl inositol 3-kinase (PI3K), and MAPK pathways; human biliverdin reductase (hBVR) is an IRK substrate and pathway effector. This is the first report on hBVR peptide-mediated IRK activation and conformational change. 290KYCCSRK, which increased IRK Vmax without changing Km, stimulated glucose uptake and potentiated insulin and IGF-1 stimulation in 4 cell lines. KYCCSRK in native hBVR was necessary for the hBVR and IRK cross-activation. Peptide treatment also activated PI3K downstream effectors, Akt and ERK, phosphorylation, and Elk transcriptional activity. In cells transfected with CMV-regulated EGFP-VP-peptide plasmid, C292→A mutant did not stimulate glucose uptake; K296→A decreased uptake and kinase activity. KEDQYMKMTV, corresponding to hBVR's SH2-binding domain, was a potent inhibitor of glucose uptake and IRK. The mechanism of action of peptides was examined using cells expressing IRK (aa 988–1263) activated by coexpressed KYCCSRK. Three active cys-mutants of IRK, with fluorophore coupled to cysteines, C1056, C1138, or C1234, were examined for changes in fluorescence emission spectra in the presence of peptides. KYCCSRK and KEDQYMKMTV bound to different sites in IRK. The findings identify novel agents for activating or inhibiting insulin signaling and offer a new approach for treatment of type 2 diabetes and hypoglycemia.—Gibbs, P. E. M., Lerner-Marmarosh, N., Poulin, A., Farah, E., Maines, M. D. Human biliverdin reductase-based peptides activate and inhibit glucose uptake through direct interaction with the kinase domain of insulin receptor. PMID:24568842

  10. Insulin secretion in health and disease: nutrients dictate the pace.

    PubMed

    Regazzi, Romano; Rodriguez-Trejo, Adriana; Jacovetti, Cécile

    2016-02-01

    Insulin is a key hormone controlling metabolic homeostasis. Loss or dysfunction of pancreatic β-cells lead to the release of insufficient insulin to cover the organism needs, promoting diabetes development. Since dietary nutrients influence the activity of β-cells, their inadequate intake, absorption and/or utilisation can be detrimental. This review will highlight the physiological and pathological effects of nutrients on insulin secretion and discuss the underlying mechanisms. Glucose uptake and metabolism in β-cells trigger insulin secretion. This effect of glucose is potentiated by amino acids and fatty acids, as well as by entero-endocrine hormones and neuropeptides released by the digestive tract in response to nutrients. Glucose controls also basal and compensatory β-cell proliferation and, along with fatty acids, regulates insulin biosynthesis. If in the short-term nutrients promote β-cell activities, chronic exposure to nutrients can be detrimental to β-cells and causes reduced insulin transcription, increased basal secretion and impaired insulin release in response to stimulatory glucose concentrations, with a consequent increase in diabetes risk. Likewise, suboptimal early-life nutrition (e.g. parental high-fat or low-protein diet) causes altered β-cell mass and function in adulthood. The mechanisms mediating nutrient-induced β-cell dysfunction include transcriptional, post-transcriptional and translational modifications of genes involved in insulin biosynthesis and secretion, carbohydrate and lipid metabolism, cell differentiation, proliferation and survival. Altered expression of these genes is partly caused by changes in non-coding RNA transcripts induced by unbalanced nutrient uptake. A better understanding of the mechanisms leading to β-cell dysfunction will be critical to improve treatment and find a cure for diabetes.

  11. RNA-dependent protein kinase (PKR) depletes nutrients, inducing phosphorylation of AMP-activated kinase in lung cancer.

    PubMed

    Guo, Chengcheng; Hao, Chuncheng; Shao, RuPing; Fang, Bingliang; Correa, Arlene M; Hofstetter, Wayne L; Roth, Jack A; Behrens, Carmen; Kalhor, Neda; Wistuba, Ignacio I; Swisher, Stephen G; Pataer, Apar

    2015-05-10

    We have demonstrated that RNA-dependent protein kinase (PKR) and its downstream protein p-eIF2α are independent prognostic markers for overall survival in lung cancer. In the current study, we further investigate the interaction between PKR and AMPK in lung tumor tissue and cancer cell lines. We examined PKR protein expression in 55 frozen primary lung tumor tissues by Western blotting and analyzed the association between PKR expression and expression of 139 proteins on tissue samples examined previously by Reverse Phase Protein Array (RPPA) from the same 55 patients. We observed that biomarkers were either positively (phosphorylated AMP-activated kinase(T172) [p-AMPK]) or negatively (insulin receptor substrate 1, meiotic recombination 11, ATR interacting protein, telomerase, checkpoint kinase 1, and cyclin E1) correlated with PKR. We further confirmed that induction of PKR with expression vectors in lung cancer cells causes activation of the AMPK protein independent of the LKB1, TAK1, and CaMKKβ pathway. We found that PKR causes nutrient depletion, which increases AMP levels and decreases ATP levels, causing AMPK phosphorylation. We further demonstrated that inhibiting AMPK expression with compound C or siRNA enhanced PKR-mediated cell death. We next explored the combination of PKR and p-AMPK expression in NSCLC patients and observed that expression of p-AMPK predicted a poor outcome for adenocarcinoma patients with high PKR expression and a better prognosis for those with low PKR expression. These findings were consistent with our in vitro results. AMPK might rescue cells facing metabolic stresses, such as ATP depletion caused by PKR. Our data indicate that PKR causes nutrient depletion, which induces the phosphorylation of AMPK. AMPK might act as a protective response to metabolic stresses, such as nutrient deprivation.

  12. Uptake of Optional Activities Leads to Improved Performance in a Biomedical Sciences Class

    ERIC Educational Resources Information Center

    Verkade, Heather; Lim, Saw Hoon

    2015-01-01

    Optional (non-assessed) learning activities are a learning tool that may help students achieve their desired grade, or help students with lower levels of previous experience in the topic. This study examines the implementation of, and outcomes from, two optional activities, one online and one paper-based. The activities complemented the lectures…

  13. mTOR-dependent activation of the transcription factor TIF-IA links rRNA synthesis to nutrient availability.

    PubMed

    Mayer, Christine; Zhao, Jian; Yuan, Xuejun; Grummt, Ingrid

    2004-02-15

    In cycling cells, transcription of ribosomal RNA genes by RNA polymerase I (Pol I) is tightly coordinated with cell growth. Here, we show that the mammalian target of rapamycin (mTOR) regulates Pol I transcription by modulating the activity of TIF-IA, a regulatory factor that senses nutrient and growth-factor availability. Inhibition of mTOR signaling by rapamycin inactivates TIF-IA and impairs transcription-initiation complex formation. Moreover, rapamycin treatment leads to translocation of TIF-IA into the cytoplasm. Rapamycin-mediated inactivation of TIF-IA is caused by hypophosphorylation of Se 44 (S44) and hyperphosphorylation of Se 199 (S199). Phosphorylation at these sites affects TIF-IA activity in opposite ways, for example, phosphorylation of S44 activates and S199 inactivates TIF-IA. The results identify a new target formTOR-signaling pathways and elucidate the molecular mechanism underlying mTOR-dependent regulation of RNA synthesis.

  14. Pigs that are divergent in feed efficiency, differ in intestinal enzyme and nutrient transporter gene expression, nutrient digestibility and microbial activity.

    PubMed

    Vigors, S; Sweeney, T; O'Shea, C J; Kelly, A K; O'Doherty, J V

    2016-11-01

    Feed efficiency is an important trait in the future sustainability of pig production, however, the mechanisms involved are not fully elucidated. The objective of this study was to examine nutrient digestibility, organ weights, select bacterial populations, volatile fatty acids (VFA's), enzyme and intestinal nutrient transporter gene expression in a pig population divergent in feed efficiency. Male pigs (n=75; initial BW 22.4 kg SEM 2.03 kg) were fed a standard finishing diet for 43 days before slaughter to evaluate feed intake and growth for the purpose of calculating residual feed intake (RFI). Phenotypic RFI was calculated as the residuals from a regression model regressing average daily feed intake (ADFI) on average daily gain (ADG) and midtest BW0.60 (MBW). On day 115, 16 pigs (85 kg SEM 2.8 kg), designated as high RFI (HRFI) and low RFI (LRFI) were slaughtered and digesta was collected to calculate the coefficient of apparent ileal digestibility (CAID), total tract nutrient digestibility (CATTD), microbial populations and VFA's. Intestinal tissue was collected to examine intestinal nutrient transporter and enzyme gene expression. The LRFI pigs had lower ADFI (P<0.001), improved feed conversion ratio (P<0.001) and an improved RFI value relative to HRFI pigs (0.19 v. -0.14 SEM 0.08; P<0.001). The LRFI pigs had an increased CAID of gross energy (GE), and an improved CATTD of GE, nitrogen and dry matter compared to HRFI pigs (P<0.05). The LRFI pigs had higher relative gene expression levels of fatty acid binding transporter 2 (FABP2) (P<0.01), the sodium/glucose co-transporter 1 (SGLT1) (P<0.05), the glucose transporter GLUT2 (P<0.10), and the enzyme sucrase-isomaltase (SI) (P<0.05) in the jejunum. The LRFI pigs had increased populations of lactobacillus spp. in the caecum compared with HRFI pigs. In colonic digesta HRFI pigs had increased acetic acid concentrations (P<0.05). Differences in nutrient digestibility, intestinal microbial populations and gene

  15. In-stream biotic control on nutrient biogeochemistry in a forested stream, West Fork of Walker Branch

    NASA Astrophysics Data System (ADS)

    Roberts, Brian J.; Mulholland, Patrick J.

    2007-12-01

    A growing body of evidence demonstrates the importance of in-stream processing in regulating nutrient export, yet the influence of temporal variability in stream metabolism on net nutrient uptake has not been explicitly addressed. Stream water DIN and SRP concentrations in Walker Branch, a first-order deciduous forest stream in eastern Tennessee, show a repeated pattern of annual maxima in summer and biannual minima in spring and autumn. Temporal variations in catchment hydrologic flow paths result in lower winter and higher summer nutrient concentrations, but do not explain the spring and autumn nutrient minima. Ambient nutrient uptake rates were measured 2-3 times per week over an 18-month period and compared to daily rates of gross primary production (GPP) and ecosystem respiration (ER) to examine the influence of in-stream biotic activity on nutrient export. GPP and ER rates explained 81% of the variation in net DIN retention with high net NO3- uptake (and lower net NH4+ release) rates occurring during spring and autumn and net DIN release in summer. Diel nutrient concentration patterns were examined several times throughout the year to determine the relative importance of autotrophic and heterotrophic activity on net nutrient uptake. High spring GPP corresponded to daily decreases in NO3- over the illuminated hours resulting in high diel NO3- amplitude which dampened as the canopy closed. GPP explained 91% of the variance in diel NO3- amplitude. In contrast, the autumn nutrient minima was largely explained by heterotrophic respiration since GPP remained low and little diel NO3- variation was observed during the autumn.