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Evans BR, Foston M, O'Neill HM, Reeves D, Rempe C, McGrath K, Ragauskas AJ, Davison BH. Production of deuterated biomass by cultivation of Lemna minor (duckweed) in D 2O. PLANTA 2019; 249:1465-1475. [PMID: 30697645 DOI: 10.1007/s00425-019-03097-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/21/2019] [Indexed: 06/09/2023]
Abstract
Common duckweed Lemna minor was cultivated in 50% D2O to produce biomass with 50-60% deuterium incorporation containing cellulose with degree of polymerization close (85%) to that of H2O-grown controls. The small aquatic plant duckweed, particularly the genus Lemna, widely used for toxicity testing, has been proposed as a potential source of biomass for conversion into biofuels as well as a platform for production of pharmaceuticals and specialty chemicals. Ability to produce deuterium-substituted duckweed can potentially extend the range of useful products as well as assist process improvement. Cultivation of these plants under deuterating conditions was previously been reported to require addition of kinetin to induce growth and was hampered by anomalies in cellular morphology and protein metabolism. Here, we report the production of biomass with 50-60% deuterium incorporation by long-term photoheterotrophic growth of common duckweed Lemna minor in 50% D2O with 0.5% glucose. L. minor grown in 50% D2O without addition of kinetin exhibited a lag phase twice that of H2O-grown controls, before start of log phase growth at 40% of control rates. Compared to continuous white fluorescent light, growth rates increased fivefold for H2O and twofold for 50% D2O when plants were illuminated at higher intensity with a metal halide lamp and a diurnal cycle of 12-h light/12-h dark. Deuterium incorporation was determined by a combination of 1H and 2H nuclear magnetic resonance (NMR) to be 40-60%. The cellulose from the deuterated plants had an average-number degree of polymerization (DPn) and polydispersity index (PDI) close to that of H2O-grown controls, while Klason lignin content was reduced. The only major gross morphological change noted was root inhibition.
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Affiliation(s)
- Barbara R Evans
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
| | - Marcus Foston
- Institute of Paper Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, 63130, USA
| | - Hugh M O'Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - David Reeves
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN, 37996, USA
| | - Caroline Rempe
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- School of Genome Science and Technology, F337 Walters Life Science, University of Tennessee, Knoxville, 37996, TN, USA
| | - Kathi McGrath
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Sierra Vista High School, Las Vegas, NV, USA
| | - Arthur J Ragauskas
- Institute of Paper Science and Technology, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN, 37996, USA
| | - Brian H Davison
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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Rubio L, García D, García-Sánchez MJ, Niell FX, Felle HH, Fernández JA. Direct uptake of HCO 3- in the marine angiosperm Posidonia oceanica (L.) Delile driven by a plasma membrane H + economy. PLANT, CELL & ENVIRONMENT 2017; 40:2820-2830. [PMID: 28815648 DOI: 10.1111/pce.13057] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Seagrasses access HCO3- for photosynthesis by 2 mechanisms, apoplastic carbonic anhydrase-mediated dehydration of HCO3- to CO2 and direct HCO3- uptake. Here, we have studied plasma membrane energization and the mechanism for HCO3- import in Posidonia oceanica. Classical electrophysiology and ion-selective microelectrodes were used to measure the membrane potential, cytosolic pH, and the cytosolic concentrations of Na+ and Cl- upon the addition of HCO3- . The photosynthetic response to HCO3- and to inhibitors was also measured. Results indicate that the primary pump of P. oceanica plasma membrane is a fusicoccin-sensitive H+ -ATPase. Bicarbonate depolarizes the plasma membrane voltage and transiently acidifies the cytosol, indicating that HCO3- is transported into the cells by an H+ -symport. Initial cytosolic acidification is followed by an alkalinization, suggesting an internal dehydration of HCO3- . The lack of cytosolic Na+ and Cl- responses rules out the contribution of these ions to HCO3- transport. The energetics of nH+ /HCO3- symport allows, for n = 1, an estimate of cytosolic accumulation of 0.22 mM HCO3- . Because this transporter could permit accumulation of HCO3- up to 100 times above the equilibrium concentration, it would be a significant component of a carbon-concentrating mechanism in this species.
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Affiliation(s)
- Lourdes Rubio
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
| | - Delia García
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
| | - María J García-Sánchez
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
| | - F Xavier Niell
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
| | - Hubert H Felle
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
| | - José A Fernández
- Departamento de Biología Vegetal, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos S/N, Málaga, 29071, Spain
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Conversion of solar energy into electricity by using duckweed in Direct Photosynthetic Plant Fuel Cell. Bioelectrochemistry 2012; 87:185-91. [DOI: 10.1016/j.bioelechem.2012.02.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 02/27/2012] [Accepted: 02/28/2012] [Indexed: 11/15/2022]
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4
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Miller AJ, Cookson SJ, Smith SJ, Wells DM. The use of microelectrodes to investigate compartmentation and the transport of metabolized inorganic ions in plants. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:541-549. [PMID: 11373303 DOI: 10.1093/jexbot/52.356.541] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Microelectrode measurements can be used to investigate both the intracellular pools of ions and membrane transport processes of single living cells. Microelectrodes can report these processes in the surface layers of root and leaf cells of intact plants. By careful manipulation of the plant, a minimum of disruption is produced and therefore the information obtained from these measurements most probably represents the 'in vivo' situation. Microelectrodes can be used to assay for the activity of particular transport systems in the plasma membrane of cells. Compartmental concentrations of inorganic metabolite ions have been measured by several different methods and the results obtained for the cytosol are compared. Ion-selective microelectrodes have been used to measure the activities of ions in the apoplast, cytosol and vacuole of single cells. New sensors for these microelectrodes are being produced which offer lower detection limits and the opportunity to measure other previously unmeasured ions. Measurements can be used to determine the intracellular steady-state activities or report the response of cells to environmental changes.
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Affiliation(s)
- A J Miller
- Department of Biochemistry and Physiology, IACR-Rothamsted, Harpenden, Hertfordshire AL5 2JQ, UK.
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5
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Lass B, Thiel G, Ullrich-Eberius CI. Electron transport across the plasmalemma of Lemna gibba G1. PLANTA 1986; 169:251-259. [PMID: 24232558 DOI: 10.1007/bf00392322] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/1986] [Accepted: 06/05/1986] [Indexed: 06/02/2023]
Abstract
Lemna gibba L., grown in the presence or absence of Fe, reduced extracellular ferricyanide with a V max of 3.09 μmol · g(-1) fresh weight · h(-1) and a K m of 115 μM. However, Fe(3+)-ethylenediaminetetraacetic acid (EDTA) was reduced only after Fe-starvation. External electron acceptors such as ferricyanide, Fe(3+)-EDTA, 2,6-dichlorophenol indophenol or methylene blue induced a membrane depolarization of up to 100 mV, but electron donors such as ferrocyanide or NADH had no effect. Light or glucose enhanced ferricyanide reduction while the concomitant membrane depolarization was much smaller. Under anaerobic conditions, ferricyanide had no effect on electrical membrane potential difference (Em). Ferricyanide reduction induced H(+) and K(+) release in a ratio of 1.16 H(+)+1 K(+)/2 e(-) (in +Fe plants) and 1.28 H(+)+0.8 K(+)/2 e(-) (in -Fe plants). Anion uptake was inhibited by ferricyanide reduction. It is concluded that the steady-state transfer of electrons and protons proceeds by separate mechanisms, by a redox system and by a H(+)-ATPase.
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Affiliation(s)
- B Lass
- Institut für Botanik der Technischen Hochschule, Schnittspahnstrasse 3, D-6100, Darmstadt, Federal Republic of Germany
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Effect of Helminthosporium sacchari-toxin on cell membrane potential of susceptible sugarcane. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/0048-4059(85)90017-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Lass B, Ullrich-Eberius CI. Evidence for proton/sulfate cotransport and its kinetics inLemna gibba G1. PLANTA 1984; 161:53-60. [PMID: 24253555 DOI: 10.1007/bf00951460] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/1983] [Accepted: 12/21/1983] [Indexed: 05/04/2023]
Abstract
Sulfate uptake into duckweed (Lemna gibba G1) was studied by means of [(35)S]sulfate influx and measurements of electrical membrane potential. Uptake was strongly regulated by the intracellular content of soluble sulfate. At the onset of sulfate uptake the membrane potential was transiently depolarized. Fusicoccin stimulated uptake up to 165% of the control even at pH 8. It is suggested that sulfate uptake is energized in the whole pH range by a 3H(+)/sulfate cotransport mechanism. Kinetics of sulfate uptake and sulfate-induced membrane depolarization in the concentration range of 5 μM to 1 mM sulfate at pH 5.7 was best described by two Michaelis-Menten terms without any linear component. The second system had a lower affinity for sulfate and was fully active only at sufficiently high proton concentrations.
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Affiliation(s)
- B Lass
- Institut für Botanik der Technischen Hochschule, Schnittspahnstrasse 3, D-6100, Darmstadt, Germany
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8
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Ullrich-Eberius CI, Novacky A, van Bel AJ. Phosphate uptake inLemna gibba G1: energetics and kinetics. PLANTA 1984; 161:46-52. [PMID: 24253554 DOI: 10.1007/bf00951459] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/1983] [Accepted: 12/21/1983] [Indexed: 05/28/2023]
Abstract
Phosphate uptake was studied by determining [(32)P]phosphate influx and by measurements of the electrical membrane potential in duckweed (Lemna gibba L.). Phosphate-induced membrane depolarization (ΔE m ) was controlled by the intracellular phosphate content, thus maximal ΔE m by 1 mM H2PO 4 (-) was up to 133 mV after 15d of phosphate starvation. The ΔE m was strongly dependent on the extracellular pH, with a sharp optimum at pH 5.7. It is suggested that phosphate uptake is energized by the electrochemical proton gradient, proceeding by a 2H(+)/H2PO 4 (-) contransport mechanism. This is supported also by the fusicoccin stimulation of phosphate influx. Kinetics of phosphate influx and of ΔE m , which represent mere plasmalemma transport, are best described by two Michaelis-Menten terms without any linear components.
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Affiliation(s)
- C I Ullrich-Eberius
- Institut für Botanik der Technischen Hochschule, Schnittspahnstrasse 3, D-6100, Darmstadt, Germany
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9
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Katou K, Tomiyama K, Okamoto H. Effects of hyphal wall components of Phytophthora infestans on membrane potential of potato tuber cells. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0048-4059(82)90065-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Suzuki M. Sugar co-transport with H+ in Vinca protoplasts: Inhibition of the uptake by ATPase inhibitors. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0304-4211(82)90146-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Dalessandro G, Mastropasqua L. Effects of Zeatin, Fusicoccin and Zeatin-Fusicoccin Treatments on Cell Wall Polysaccharide Biosynthesis During Expansion Growth in Excised Radish Cotyledons. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0044-328x(82)80148-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Novacky A, Ullrich-Eberius C. Relationship between membrane potential and ATP level in Xanthomonas campestris pv. malvacearum infected cotton cotyledons. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/0048-4059(82)90042-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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14
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15
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Morgutti S, Ferrari-Bravo P, Marre M, Cocucci S. Effects of Ni2+ on proton extrusion and related transport processes and on the transmembrane electrical potential in maize roots. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0304-4211(81)90001-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Amino Acid Uptake by Various Tissues of the Tomato Plant. Effects of the External pH and Light. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0044-328x(81)80017-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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18
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van Bel AJ, Ammerlaan A. Light-promoted diffusional amino acid efflux from Commelina leaf disks : Indirect control by proton pump activities. PLANTA 1981; 152:115-123. [PMID: 24302378 DOI: 10.1007/bf00391182] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/1980] [Accepted: 02/02/1981] [Indexed: 06/02/2023]
Abstract
The release (=the measured loss) of amino acids was studied in Commelina benghalensis leaf disks. The release is assumed to be the result of influx and efflux, therefore, both movements were investigated.The uptake of (14)C-labeled valine exhibited a biphasic isotherm. The uptake was pH-dependent, especially at low substrate concentrations (pH optimum 4.8). Signals for amino acid/proton co-transport were observed: stimulation of the uptake by fusicoccin (FC), inhibition by diethylstilbestrol (DES) or by high K(+) concentrations. In the light, the ATP level of the disks was maintained during the uptake period (2 h), in darkness the ATP content decreased from 87 to 24 nmol g(-1) fr. wt. However, light-promoted uptake, which is explained in the proton pump concept by an intensified proton extrusion as the result of high ATP production, was lacking.The release of amino acids was increased by washing with p-chloromercuriphenyl sulphonic acid (PCMBS), nystatin, 3(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), or KCN. The release (Q10 about 1.5) was independent of the external pH and was linearly related to the intracellular amino acid concentration. Light enhanced the rate of release to the same extent at all intracellular concentrations. The present results suggest that the release is balanced by a, at least partially, proton-driven influx and a diffusional ligh-promoted efflux. A provisional model shows how the diffusional effulx can be indirectly controlled by a counter-flow fueled by the metabolism.
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Affiliation(s)
- A J van Bel
- Botanisch Laboratorium van de Rijksuniversiteit, Lange Nieuwstraat 106, 3512 PN, Utrecht, The Netherlands
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19
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Lüttge U, Jung KD, Ullrich-Eberius C. Evidence for Amino Acid-H+ Cotransport in Lemna gibba Given by Effects of Fusicoccin. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0044-328x(81)80190-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Löppert H. Energy coupling for membrane hyperpolarization in Lemna: Evidence against an ATP-fueled electrogenic pump as the exclusive mechanism. PLANTA 1981; 151:293-297. [PMID: 24301857 DOI: 10.1007/bf00395183] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/1979] [Accepted: 10/27/1980] [Indexed: 06/02/2023]
Abstract
The vacuolar electrical potential of Lemna paucicostata 6746 has an active component of about-130 mV. This hyperpolarization above the diffusion potential was maintained when dicyclohexyl carbodiimide (DCCD) or arsenate (0.1 mM or 5 mM final concentrations, respectively) were added in the light or after the plants had been kept in darkness for 1 h. The ATP level was reduced to 11±3% by DCCD and to 56±6% by arsenate under conditions identical to those during the potential measurements. In this report, it is discussed whether these results could be interpreted in terms of a putative electrogenic ATPase in the plasma membrane of Lemna. Rb(+)-influx in illuminated plants was 12.5% or 52% of the control when ATP generation was inhibited by DCCD or arsenate. This finding is regarded as justifying the assumption that the availability of ATP at plasmalemma-located transport sites is drastically decreased by these inhibitors.A passive proton-permeability in the cell membrane was induced with different concentrations of carbonyl cyanide m-chlorophenyl hydrazone (CCCP). The potential decrease, caused by the current through this shunt, was not affected by DCCD. It therefore seems less conceivable that the cell membrane remains hyperpolarized because of an increase of membrane resistance concomitant to the inhibition of the pump.The significance of respiratory processes for membrane hyperpolarization is displayed by the depolarizing action of anoxia or KCN. As ATP was found to be non-limiting under these conditions, the inhibition of the electrogenic pump is regarded as being in discord with the concept of an electrogenic ATPase, which is solely responsible for membrane hyperpolarization.
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Affiliation(s)
- H Löppert
- Botanisches Institut der Universität für Bodenkultur, Gregor-Mendel-Straße 33, A-1180, Vienna, Austria
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Jung KD, Lüttge U. Amino acid uptake by Lemna gibba by a mechanism with affinity to neutral L-and D-amino acids. PLANTA 1980; 150:230-235. [PMID: 24306687 DOI: 10.1007/bf00390831] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/1980] [Accepted: 07/17/1980] [Indexed: 06/02/2023]
Abstract
Earlier work suggested that amino acid uptake by Lemna gibba cells is a H(+)-cotransport mechanism driven by a proton-electrochemical gradient at the plasmalemma. The present investigations of the transient membrane depolarizations elicited by amino acids and tracer-uptake experiments show that all neutral α-L-amino acids, D-alanine and analogues, like β-alanine and p-fluorophenylalanine, are transported by the same system. It remains to be seen if there are separate mechanisms for the uptake of acidic and basic amino acids.
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Affiliation(s)
- K D Jung
- Institut für Botanik, Technische Hochschule Darmstadt, Schnittspahnstraße 3-5, D-6100, Darmstadt, Federal Republic of Germany
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Van Bel A, Van Der Schoot C. Light-stimulated biphasic amino acid uptake by xylem parenchyma cells. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0304-4211(80)90085-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Effect of fusicoccin on the membrane potential, on the uptake of glucose and glycine, and on the ATP level in Lemna gibba G1. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0304-4211(80)90111-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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24
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Hartung W, Ullrich-Eberius CI, Lüttge U, Böcher M, Novacky A. Effect of abscisic acid on membrane potential and transport of glucose and glycine in Lemna gibba G1. PLANTA 1980; 148:256-261. [PMID: 24309828 DOI: 10.1007/bf00380036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/1979] [Accepted: 11/29/1979] [Indexed: 06/02/2023]
Abstract
The membrane potential of Lemna gibba G1 was measured with a microelectrode; glucose and glycine uptake were measured with (14)C-labeled substances. The membrane potential was increased by 85 mV on the average, after the plants had been pretreated with 10 μM abscisic acid (ABA) for more than 30 min. This effect is not linked to the endogenous level of soluble sugars. The concentration of these soluble sugars was increased to more than 200% by pretreatment of the plants with ABA, however, the respiration of the plants was not affected. ABA stimulated uptake of glucose and glycine. Glucose- and glycine-dependent depolarization and repolarization of the membrane was altered: depolarization was less and repolarization was slower; during uptake of glycine, the first typical phase of repolarization was suppressed. The data suggest that ABA interferes with the primary steps of substrate uptake.
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Affiliation(s)
- W Hartung
- Lehrstuhl Botanik I, Botanisches Institut, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Germany
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25
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Martin E, Komor E. Role of phloem in sucrose transport by Ricinus cotyledons. PLANTA 1980; 148:367-373. [PMID: 24310140 DOI: 10.1007/bf00388125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/1979] [Accepted: 11/29/1979] [Indexed: 06/02/2023]
Abstract
Sucrose is taken up and accumulated by cotyledons of Ricinus communis L. Autoradiographic studies reveal a predominant accumulation of sucrose in the phloem of the cotyledons. The export of sucrose from the cotyledons to hypocotyl and roots proceeds in the phloem by mass flow. These results, taken together with previous data, are experimental evidence for proton-sucrose symport as the mechanism of phloem loading.
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Affiliation(s)
- E Martin
- Institut für Botanik, Fachbereich Biologie und Vorklinische Medizin der Universität Regensburg, Universitätsstra\e 31, D-8400, Regensburg, Federal Republic of Germany
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Cho BH, Komor E. The role of potassium in charge compensation for sucrose-proton-symport by cotyledons of Ricinus communis. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0304-4211(80)90129-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Felle H, Bentrup FW. Hexose transport and membrane depolarization in Riccia fluitans. PLANTA 1980; 147:471-476. [PMID: 24311171 DOI: 10.1007/bf00380190] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/1979] [Accepted: 10/09/1979] [Indexed: 06/02/2023]
Abstract
In the aquatic liverwort Riccia fluitans, the uptake of (14)C-labeled 3-O-methyl glucose (3-OMG) and membrane depolarization (ΔΨ m ) caused by different hexoses has been studied as a function of time and concentration of hexose, K(+) and H(+), respectively. The rate of uptake of the non-metabolized 3-OMG shows two components: (A)A pH-dependent saturable uptake with a km value around 0.1 mM which saturates at 2.1 and 7.2 μmol G DW (-1) h(-1) at pH 6.8 and 5.0, respectively; and (B) a pH-insensitive uptake component which increases linearly with the external 3-OMG concentration and does not saturate ≦4 mM. Hexoses rapidly depolarize the plasmalemma of the thallus cell and increase its electrical conductance. The maximal ΔΨ m was 60±2 mV, the concentrations (mM) for half-maximal ΔΨ m were 0.24 glucose, 0.32 galactose, 0.37 2-deoxy glucose, 0.38 3-OMG, 0.57 mannose, and 34 fructose. In terms of a hexose carrier model and an equivalent circuit for the hexose-induced depolarized state of the membrane, it is proposed that a hexose carrier operates either electrogenically in its protonated, pH-and voltage-sensitive state, or by transmembrane diffusion of its uncharged state.
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Affiliation(s)
- H Felle
- Abteilung Biophysik der Pflanzen, Institut für Biologie I der Universität, Auf der Morgenstelle 1, D-7400, Tübingen, Federal Republic of Germany
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Novacky A, Ullrich-Eberius CI, Lüttge U. pH and membrane-potential changes during glucose uptake inLemna gibba G1 and their response to light. PLANTA 1980; 149:321-326. [PMID: 24306366 DOI: 10.1007/bf00571164] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/1979] [Accepted: 07/15/1980] [Indexed: 06/02/2023]
Abstract
Extracellular pH was measured with a microelectrode positioned over the lower surface of singleLemna gibba plants. Upon addition of glucose, a transient extracellular alkalinization occurred. Saturated extracellular pH changes were observed with 5 mM glucose. Simultaneously, the membrane potential difference of -250 mV in the dark measured with intracellular glass micropipettes, trnasiently decreased by 105 mV. Uptake of [(14)C]glucose and extracellular alkalinization was enhanced by light whereas glucose-induced membrane-potential changes were reduced in the light and became even smaller with increasing the preillumination time. Glucose uptake was optimal at pH 6. The results are taken as further evidence in favor of H(+)-glucose cotransport inLemna.
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Affiliation(s)
- A Novacky
- Department of Plant Pathology, University of Missouri-Columbia, 108 Waters Hall, 65211, Columbia, MO, USA
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Electrochemical investigation of active malic acid transport at the tonoplast into the vacuoles of the CAM plantKalanchoë daigremontiana. J Membr Biol 1979. [DOI: 10.1007/bf01869746] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Löppert H. Evidence for electrogenic proton extrusion by subepidermal cells of Lemna paucicostata 6746. PLANTA 1979; 144:311-315. [PMID: 24407319 DOI: 10.1007/bf00391573] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/1978] [Accepted: 10/23/1978] [Indexed: 06/03/2023]
Abstract
The cell potential of Lemna paucicostata 6746 was measured between the vacuole and the external solution. The potential in the dark (-202 mV) could be depolarized with 0.1 mM dicyclohexyl carbodiimide (DCCD) or 1 mM arsenate to-81 mV. The hyperpolarization above the latter value is therefore attributed to an ATP-dependent process. The cell potential showed a significant dependence upon the pH of the external solution. The change in the potential induced by a jump in pH between two certain values, was reversible and independent of the mode of performing the pH change (stepwise or at once). The DCCD-or arsenate-depolarized potential did not respond to external pH changes. A 0.1 mM ammonium chloride solution depolarized the cell potential reversibly to-83 mV. This potential-change could be greatly reduced by simultaneous addition of 5 mM Na isobutyrate. The pH sensitivity of the cell potential is ascribed to changes in the rate of proton extrusion upon altering the proton gradient across the plasmalemma. The effects of ammonium and isobutyrate are interpreted as being the consequence of pH shifts at the inner face of the plasmalemma, caused by the permeation of the undissociated form of the weak acid or base. A critical discussion of an alternative interpretation for the ammonium effect is presented.
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Affiliation(s)
- H Löppert
- Botanisches Institut der Universität für Bodenkultur, Gregor Mendel Straße 33, A-1180, Vienna, Austria
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Novacky A, Fischer E. Membrane potential changes during transport of glycine as a neutral amino acid and nitrate in Lemna gibba
G 1. FEBS Lett 1978. [DOI: 10.1016/0014-5793(78)80189-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ullrich-Eberius CI, Novacky A, Lüttge U. Active hexose uptake in Lemna gibba G1. PLANTA 1978; 139:149-153. [PMID: 24414154 DOI: 10.1007/bf00387140] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/1977] [Accepted: 11/21/1977] [Indexed: 06/03/2023]
Abstract
Growth of autotrophically growing duck-weeds (Lemna gibba L., G1) was stimulated by sucrose. The rate of respiration increased when plants had been grown on sucrose (8.7 μmol O2 g(-1) fresh weight (FW) h(-1)) and was reduced after growth without sucrose in the dark or under longday conditions (2.5 μmol O2 g(-1) FW h(-1)). Photosynthesis was induced already by low light intensities (0.1 klx).Short-time application of glucose or sucrose stimulated respiration in proportion to the hexose uptake rate. Sucrose is probably not taken up as the disaccharide. The transported sugar species after addition of sucrose are its hexose moieties produced by the high activity of the cell wall invertase. Fructose stimulated to a lesser extent; mannitol induced no enhancement; 2-deoxyglucose slightly inhibited O2 uptake. After mild carbon starvation of the plants the uptake of glucose and 3-O-methylglucose proceeded without any lag phase, with similar saturation kinetics in both cases. The initial uptake rate at substrate saturation was 2.6 μmol glucose g(-1) FW h(-1) in the dark. Light stimulated hexose uptake by 2 to 3 times. The results show that Lemna gibba has an energy-dependent constitutive system for hexose uptake.
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Affiliation(s)
- C I Ullrich-Eberius
- Institut für Botanik der Technischen Hochschule, Schnittspahnstr. 3-5, D-6100, Darmstadt, Federal Republic of Germany
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