Simultaneous determination of membrane potential and pH gradient by photodiode array spectroscopy

Konishi, Tetsuya; Murakami, Naoyuki; Hatano, Yoshihiko; Nakazato, Ken’ichiro

doi:10.1016/0005-2736(86)90229-4

Cited by 17 publications

(6 citation statements)

References 12 publications

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“…It has been shown previously with the help of a fluorescent potential dependent probe DiS-C3- (5), that monensin is capable of transporting K + cations through membranes of liposomes in an electrogenic manner similar to valinomycin [20,52]. To confirm this conclusion and to compare the actions of monensin and ethyl-monensin, experiments were performed to check the potential dependent uptake of a cationic dye rhodamine 6G by the method of fluorescent correlation spectroscopy (FCS).…”

Section: Resultsmentioning

confidence: 87%

“…The mixture was vortexed, passed through a cycle of freezing and thawing, and extruded through 0.1-μM pore size Nucleopore polycarbonate membranes using an Avanti Mini-Extruder. The membrane potentials of liposomes were generated and measured via fluorescence of DiS-C3-(5) of a suspension of liposomes after the addition of valinomycin, monensinin, or ethyl-monensin in a buffer containing 100 mM choline chloride, 10 mM Tris, pH 7.4 as described previously [37]. The fluorescence at 690 nm (excitation at 650 nm) was monitored with a Panorama Fluorat 02 spectrofluorimeter (Lumex, Russia).…”

Section: Measurements Of Electrical Potential On Membranes Of Liposommentioning

confidence: 99%

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Electrogenic and nonelectrogenic ion fluxes across lipid and mitochondrial membranes mediated by monensin and monensin ethyl ester

Antonenko

Rokitskaya

Huczyński

2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Monensin is a carrier of cations through lipid membranes capable of exchanging sodium (potassium) cations for protons by an electroneutral mechanism, whereas its ethyl ester derivative ethyl-monensin is supposed to transport sodium (potassium) cations in an electrogenic manner. To elucidate mechanistic details of the ionophoric activity, ion fluxes mediated by monensin and ethyl-monensin were measured on planar bilayer lipid membranes, liposomes, and mitochondria. In particular, generation of membrane potential on liposomes was studied via the measurements of rhodamine 6G uptake by fluorescence correlation spectroscopy. In mitochondria, swelling experiments were expounded by the additional measurements of respiration, membrane potential, and matrix pH. It can be concluded that both monensin and ethyl-monensin can perform nonelectrogenic exchange of potassium (sodium) ions for protons and serve as electrogenic potassium ion carriers similar to valinomycin. The results obtained are in line with the predictions based on the crystal structures of the monensin complexes with sodium ions and protons (Huczyński et al., Biochim. Biophys. Acta, 1818 (2012) pp. 2108-2119). The functional activity observed for artificial membranes and mitochondria can be applied to explain the activity of ionophores in living systems. It can also be important for studying the antitumor activity of monensin.

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Section: Resultsmentioning

confidence: 87%

Section: Measurements Of Electrical Potential On Membranes Of Liposommentioning

confidence: 99%

Electrogenic and nonelectrogenic ion fluxes across lipid and mitochondrial membranes mediated by monensin and monensin ethyl ester

Antonenko

Rokitskaya

Huczyński

2015

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…The possibility that residual organic solvents or lipid oxidation products are present that increase proton permeability (Cafiso and Hubbell, 1982;Gutknecht, 1987) should not be easily dismissed. It should also be noted that other workers (Garcia, 1984;Konishi et al, 1986) noted a lack of electrically driven proton transport, which they attributed to a threshold effect where an electrical potential of at least 60 mV is required to drive proton or proton equivalent transport.…”

Section: Discussionmentioning

confidence: 89%

“…Induced pH gradients corresponding to electrochemical equilibrium have been observed in sonicated small unilamellar vesicles (SUV) systems (Cafiso and Hubbell, 1983). However, other authors (Garcia, 1984;Konishi, 1986) have reported that electrical potentials induce much smaller pH gradients than would be expected for electrochemical equilibrium.…”

Section: Introductionmentioning

confidence: 99%

Proton flux in large unilamellar vesicles in response to membrane potentials and pH gradients

Redelmeier

Mayer

Wong

et al. 1989

Biophysical Journal

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The transport of protons across liposomes composed of phosphatidylcholine in response to electrical potentials or pH gradients has been investigated. The results support three major conclusions. The first of these concerns the need for reliable measurements of electrical potentials and pH gradients. It is shown that the potential probe tetraphenylphosphonium and the pH probe methylamine provide accurate and self consistent measures of electrical potentials and pH gradients respectively in these systems. Second, it is shown by two independent techniques that the pH gradients induced in response to valinomycin and potassium dependent electrical potentials are significantly smaller than would be expected for electrochemical equilibrium. The pH gradients observed are stable over an 8 h time course and are sensitive to the ionic composition of the buffers employed, where the presence of external sodium results in the smallest induced pH gradients. These results are discussed in terms of current models of proton conductance across membranes. In a final area of investigation, it is shown that valinomycin and carbonyl cyanide m-chlorophenyl hydrazone (CCCP) can transport sodium ions in a synergistic manner.

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“…Large unilamellar liposomes were prepared by the reverse phase evaporation method, as described previously [24]. Briefly, whole lipid extract of Gram-positive and Gram-negative bacteria were dissolved in a diethyl ether/chloroform mixture (5:1, v/v).…”

Section: Preparation Of Bacterial Membrane Liposomes (Large Unilamellmentioning

confidence: 99%

Insertion mode of a novel anionic antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly and its effect on surface potential of bacterial membrane

Tang

Shi

Zhao

et al. 2008

Journal of Pharmaceutical and Biomedical Analysis

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Simultaneous determination of membrane potential and pH gradient by photodiode array spectroscopy

Cited by 17 publications

References 12 publications

Electrogenic and nonelectrogenic ion fluxes across lipid and mitochondrial membranes mediated by monensin and monensin ethyl ester

Electrogenic and nonelectrogenic ion fluxes across lipid and mitochondrial membranes mediated by monensin and monensin ethyl ester

Proton flux in large unilamellar vesicles in response to membrane potentials and pH gradients

Insertion mode of a novel anionic antimicrobial peptide MDpep5 (Val-Glu-Ser-Trp-Val) from Chinese traditional edible larvae of housefly and its effect on surface potential of bacterial membrane

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