• Membrane and Water Treatment
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• v.3 no.1
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• pp.63-76
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• 2012

Mother liquid discharged from a salt-manufacturing plant was electrodialyzed at 25 and $40^{\circ}C$ in a continuous process integrated with $SO_4{^{2-}}$ ion low-permeable anion-exchange membranes to remove $Na_2SO_4$ and recover NaCl in the mother liquid. Performance of electrodialysis was evaluated by measuring ion concentration in a concentrated solution, permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions, current efficiency, cell voltage, energy consumption to obtain one ton of NaCl and membrane pair characteristics. The permselectivity coefficient of $SO_4{^{2-}}$ ions against $Cl^-$ ions was low enough particularly at $40^{\circ}C$ and $SO_4{^{2-}}$ transport across anion-exchange membranes was prevented successfully. Applying the overall mass transport equation, $Cl^-$ ion and $SO_4{^{2-}}$ ion transport across anion-exchange membranes is evaluated. $SO_4{^{2-}}$ ion transport number is decreased due to the decrease of electro-migration of $SO_4{^{2-}}$ ions across the anion-exchange membranes. $SO_4{^{2-}}$ ion concentration in desalting cells becomes higher than that in concentration cells and $SO_4{^{2-}}$ ion diffusion is accelerated across the anion-exchange membranes from desalting cells toward concentrating cells.

• Journal of Plant Biology
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• v.36 no.1
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• pp.67-74
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• 1993

Both polar and gravity-induced lateral transport of auxin was markedly reduced in corn coleoptile segments by octanol treatment. Octanol enhance net auxin uptake without affecting that of benzoic acid, suggesting that the effect did not result from a nonspecific action on general membrane permeability. Since naphthylphthalamic acid (NPA) action on both transport and net uptake of auxin was substantially decreased in the presence of octanol, a specific interaction of octanol with the NPA site (efflux carrier) can be postulated. Studies on in vitro binding of NPA to membrane vesicles indicated that octanol did not interfere with NPA binding. When basipetal transport of auxin was impared by plasmolysis, octanol still inhibited auxin transport in the plasmolyzed tissues. The results ruled out the possibility of octanol acting at the plasmodesmata. Kinetic analysis of growth indicated that IAA-sustained growth was rapidly blocked by octanol implicating a common system by which auxin transport is linked to auxin action. Possible mechanisms for octanol action will be discussed.

• BMB Reports
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• v.45 no.2
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• pp.96-101
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• 2012

Urea-based nitrogen fertilizer was widely utilized in maize production, but transporters involved in urea uptake, translocation and cellular homeostasis have not been identified. Here, we isolated three maize aquapoin genes, ZmNIP2;1, ZmNIP2;4 and ZmTIP4;4, from a cDNA library by heterogous complementation of a urea uptake-defective yeast. ZmNIP2;1 and ZmNIP2;4 belonged to the nodulin 26-like intrinsic proteins (NIPs) localized at plasma membrane, and ZmTIP4;4 belonged to the tonoplast intrinsic protein (TIPs) at vacuolar membrane. Quantitative RT-PCR revealed that ZmNIP2;1 was expressed constitutively in various organs while ZmNIP2;4 and ZmTIP4;4 transcripts were abundant in reproductive organs and roots. Expression of ZmTIP4;4 was significantly increased in roots and expanded leaves under nitrogen starvation, while those of ZmNIP2;1 and ZmNIP2;4 remained unaffected. Functions of maize aquapoin genes in urea transport together with their distinct expression manners suggested that they might play diverse roles on urea uptake and translocation, or equilibrating urea concentration across tonoplast.

• BMB Reports
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• v.38 no.4
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• pp.481-485
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• 2005

The response of Spirulina (Arthrospira) platensis to high salt stress was investigated by incubating the cells in light of moderate intensity in the presence of 0.8 M NaCl. NaCl caused a decrease in photosystem II (PSII) mediated oxygen evolution activity and increase in photosystem I (PSI) activity and the amount of P700. Similarly maximal efficiency of PSII (Fv/Fm) and variable fluorescence (Fv/Fo) were also declined in salt-stressed cells. Western blot analysis reveal that the inhibition in PSII activity is due to a 40% loss of a thylakoid membrane protein, known as D1, which is located in PSII reaction center. NaCl treatment of cells also resulted in the alterations of other thylakoid membrane proteins: most prominently, a dramatic diminishment of the 47-kDa chlorophyll protein (CP) and 94-kDa protein, and accumulation of a 17-kDa protein band were observed in SDS-PAGE. The changes in 47-kDa and 94-kDa proteins lead to the decreased energy transfer from light harvesting antenna to PSII, which was accompanied by alterations in the chlorophyll fluorescence emission spectra of whole cells and isolated thylakoids. Therefore we conclude that salt stress has various effects on photosynthetic electron transport activities due to the marked alterations in the composition of thylakoid membrane proteins.

• Journal of Plant Biology
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• v.33 no.2
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• pp.111-118
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• 1990

In order to characterize the chloroplasts of Korean ginseng as a semi-shade plant and radish as a sun plant, effects of growth light intensity on photosynthetic electron transport (PS) activity in chloroplasts and superoxide (O2.-) production in thylakoid membrane by irradiation were investigated. High-light chloroplasts of both plants showed higher PS activities than those grown under ow growth light intensity. High PS II and low PS I activities in ginseng chloroplasts (ratio of PS II/PS I : 1.1) were observed, but radish chloroplasts showed low PS II and high PS I activities (ratio of PS II/PS I : 0.3). PS II activity of both plants was little affected by temperature in range of 15-35$^{\circ}C$. Activities of whole -chain (PS II+I) in ginseng and PS I in radish were increased at high temperature (4$0^{\circ}C$). Preincubation of chloroplasts at 4$0^{\circ}C$ during 30 min, as a mild heat stress, caused rapid decrease in PS II and PS II+I activities of both plants. However PS I activity was not decreased in ginseng and rather increased in radish. O2.- production (NBT reduction) in Mehler reaction in the thylakoid membrane was inhibited by DCMU in both plants. DMBIB inhibited O2.- production in ginseng, but radish was insensitive to DMBIB. Electron flow system in ginseng thylakoid membrane was more susceptible to damage of photooxidation than that of radish.

• Korean Journal of Plant Resources
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• v.19 no.1
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• pp.174-179
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• 2006

A cDNA library was constructed from leaf samples of 4-year-old Panax ginseng cultured in a field. 3,000 EST from a size selected leaf cDNA library were analyzed. The 349 of 2,896 cDNA clones has related with energy metabolism genes. The 349 known genes were categorized into nine groups according to their functional classification, aerobic respiration(48.4%), accessory proteins of electron transport and membrane associated energy conservation(17.2%), glycolysis and gluconeogenesis(3.4%), electron transport and membrane associated energy conservation(2.9%), respiration(2.0%), glycolysis methylglyoxal bypass(1.7%), metabolism of energy reserves(0.6%) and alcohol fermentation(0.3%).

• Journal of Plant Biology
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• v.34 no.4
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• pp.317-323
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• 1991

Partial recovery in auxin transport capacity from inhibition by N-naphthylphthalamic acid (NPA) was observed when corn coleoptile segments were subjected to a prolonged NPA treatment. Kinetic data indicated that the recovery time is a function of the concentration of NPA applied. Desensitization to NPA was also seen in tissue slices where NPA increased net uptake of auxin, indicating that the apparant adaptation in the auxin transport system did not results possibly from auxin accumulated during transport inhibition. Studies on in vitro binding of NPA to membrane vesicles isolated from the coleoptile indicated that preincubation of the tissue with NPA resulted in the reduced binding activity. Scatchard analysis of the data indicated that this was due to decreases in the number of NPA binding sites. The possibility of causal relationship of modified NPA receptors to the sensory adaptation in auxin transport observed in coleoptile segments will be discussed.

• Journal of Plant Biology
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• v.38 no.4
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• pp.343-348
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• 1995

Treatment of Pisum sativum tissue with the protein kinase inhibitor staurosphorine resulted in impairment of 3H-indoleacetic acid transport in etiolated stem segments. The transport inhibitiion was accompanied by an increase in net uptake of labeled auxin in the tissue. The magnitude of auxin accumulation in tissue treated with the phytotropin N-1-naphthylphthalaic acid (NPA) which specifically blocks the efflux of auxin in the plasma membrane was reduced by the protein kinase inhibitor, suggesting that inhibition of protein phosphorylation could lead to hindrance of the auxin-exporting function of NPA receptors. The flavonoid genistein which is also known to inhibit protein kinase likewise reduced NPA-induced auxin accumulation. However, the flavonoid did not bring about auxin accumulation by itself, nor did it inhibit auxin transport. In view of the finding that the flavonoid also competes with NPA for a common binding site, a mechanism for the flavonoid effect on the NPA action will be proposed.

• Journal of Plant Biology
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• v.21 no.1_4
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• pp.33-38
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• 1978

Phosphate absorption from a Na2H32PO4 solution by Oryza sativa L. was studied in order to elucidate kinetic mechanisms of ion transport. The rates of phosphate absorption from different concentraitons indicated the presence of dual mechanisms in root tips, one in the low (1$\times$10-6 to 8$\times$10-5M) and the other in the high (1$\times$10-4 to 8$\times$10-3M). A phosphate compensation point of phosphate transport was revealed with a 1$\times$10-6M solution of Na2H32PO4. The kinetic model that ion transport involves an exchange reaction of absorption and desorptin is prosposed as follows: where C represents an ionic-specific organic carrier in the membrane; M, Mo and Mi are the mineral ions, M-outside and M-inside; MC is a carrier-ion complex; and the K's represent rate constants. In this model, the Mi velocity, v, is given by: {{{{v= {dMi} over {dt}= {(K1K3Mo-K2K4Mi) Ct} over {(K2＋K3)＋K1Mo＋K4Mi} }} where Ct is equal to C＋MC, and t is time.

• Advances in Energy Research
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• v.2 no.1
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• pp.21-31
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• 2014

The use of a microporous membrane along with Au/C catalyst for direct glycerol alkaline fuel cell was investigated. In comparison with Nafion 112, the microporous Celgard 3401 membrane provides a better cell performance due to the lower ionic resistance as confirmed by impedance spectra. The single cell using Au/C as anode catalyst prepared by using PVA protection techniques provided a higher maximum power density than the single cell with commercial PtRu/C at $18.65mW\;cm^{-2}$ The short-term current decay studies show a better stability of Au/C single cell. The higher activity of Au/C over PtRu/C was owing to the lower activation loss of Awe. The magnitude of current decay indicates a low problem of glycerol crossover from anode to cathode side. The similar performance of single cell with and without humudification at cathode points out an adequate transport of water through the microporous membrane.