Evidence for Nucleotide-Dependent Passive H+ Transport Protein in the Plasma Membrane of Barley Roots

Yamashita, Kanae; Mimura, Tetsuro; Shimazaki, Ken-ichiro

doi:10.1093/pcp/pcg005

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…A nucleotide-dependent passive H + transport was demonstrated in the plasma membrane vesicles of barley roots (Yamashita et al 2003). An octylglucoside-insoluble fraction was reconstituted into liposomes showing MgATPdependent H + transport activity.…”

Section: Electrogenic H + Pump In the Regulation Of Intracellular Phmentioning

confidence: 99%

Cell physiological aspects of the plasma membrane electrogenic H + pump

Tazawa

2003

Journal of Plant Research

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This article deals with cell physiological aspects of the plasma membrane electrogenic proton (H+) pump and emphasizes the contribution of the giant algal cells of the Characeae in elucidating the mechanism of the pump. First, a history of the development of intracellular perfusion techniques in characean internodal cells is described, including preparation of tonoplast-free cells. Then, an outline of the hypothesis of the electrogenic H+ pump proposed by Kitasato is introduced, who prophesied the existence of an electric potential generated by an active H+ efflux. Subsequently, a history of finding ATP as the direct energy source of the electrogenic ion pump is presented. Quantitative agreement between the pump current and the ATP-dependent H+ efflux supports the notion that the ion carried by the electrogenic ion pump is H+. The role of the H+ pump in regulation of the cytosolic pH is discussed. Mechanisms of light-induced potential change through photosynthesis-controlled activation of the H+ pump are discussed in terms of changes in the levels of adenine nucleotides and in modulation of the Km value for the ATP of H+-ATPase. Recent progress in the molecular mechanism of the blue-light-induced activation of the H+-ATPase in guard cells is presented. However, there are cases where H+-ATPase activity is inhibited by blue light, indicating the flexibility of the control mechanisms of H+-ATPase activity. Finally, modulation of H+-pumping or H+-ATPase activities in response to environmental factors, such as anoxia, membrane excitation, osmotic and salt stresses, nutrient deficiencies and aluminum toxicity are described. Discussions are presented on the regulation of the electrogenic H+ pump.

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Section: Electrogenic H + Pump In the Regulation Of Intracellular Phmentioning

confidence: 99%

Cell physiological aspects of the plasma membrane electrogenic H + pump

Tazawa

2003

Journal of Plant Research

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Liposomal Nanocapsules in Food Science and Agriculture

Taylor

Davidson

Bruce

et al. 2005

Critical Reviews in Food Science and Nutrition

488

216

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Liposomes, spherical bilayer vesicles from dispersion of polar lipids in aqueous solvents, have been widely studied for their ability to act as drug delivery vehicles by shielding reactive or sensitive compounds prior to release. Liposome entrapment has been shown to stabilize encapsulated, bioactive materials against a range of environmental and chemical changes, including enzymatic and chemical modification, as well as buffering against extreme pH, temperature, and ionic strength changes. Liposomes have been especially useful to researchers in studies of various physiological processes as models of biological membranes in both eukaryotes and prokaryotes. Industrial applications include encapsulation of pharmaceuticals and therapeutics, cosmetics, anti-cancer and gene therapy drugs. In the food industry, liposomes have been used to deliver food flavors and nutrients and more recently have been investigated for their ability to incorporate food antimicrobials that could aid in the protection of food products against growth of spoilage and pathogenic microorganisms. In this review we briefly introduce key physicochemical properties of liposomes and review competing methods for liposome production. A survey of non-agricultural and food applications of liposomes are given. Finally, a detailed up-to-date summary of the emerging usage of liposomes in the food industry as delivery vehicles of nutrients, nutraceuticals, food additives, and food antimicrobials is provided.

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

Bose

Babourina

Shabala

et al. 2010

Journal of Experimental Botany

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

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Evidence for Nucleotide-Dependent Passive H+ Transport Protein in the Plasma Membrane of Barley Roots

Abstract: ;Plasma membranes were isolated from barley roots by two-phase partitioning, and octylglucoside-soluble and -insoluble fractions were obtained. The insoluble fractions were reconstituted into liposomes, and the plasma membrane H

Cited by 3 publications

References 27 publications

Cell physiological aspects of the plasma membrane electrogenic H + pump

Cell physiological aspects of the plasma membrane electrogenic H + pump

Liposomal Nanocapsules in Food Science and Agriculture

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

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