The mechanism of action of DNP on phospholipid bilayer membranes

McLaughlin, Stuart

doi:10.1007/bf01868062

Cited by 122 publications

(71 citation statements)

References 19 publications

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“…Barley roots also rapidly recover their ability to take up anions and cations after treatment with 10 JiM DNP at pH 5 ( Table V). The rapid response to the presence and absence of DNP and the nonspecificity of DNP observed in the present work and, in particular, the increase in the permeability of artificial membranes to K+ and H+ produced by DNP (5,16) all suggest that the permeability effects of DNP-H are directly on the plasma membranes. Other investigators of roots, yeast, or neurons have come to a similar conclusion about the effects of DNP and other phenols on permeability (4,9,18).…”

Section: Discussionsupporting

confidence: 55%

Differences between Effects of Undissociated and Anionic 2,4-Dinitrophenol on Permeability of Barley Roots

Jackson

1982

Plant Physiol.

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Effects of 2,4-dinitrophenol (DNP) and several other substituted phenols on permeability of barley roots (Hordeum vulgare var. Trebi) to ions were assayed as a function of pH and phenol concentration. Solutions containing 0.1 micromolar undissociated DNP increase the permeability of barley root cells to small ions such as K+, Na+, Ca2+, and Cl with no inhibition of respiration. Undissociated forms of the other phenols increase permeability also, but they are less effective than DNP. Only the undissociated DNP is effective. Anionic DNP does not increase permeability or inhibit ion uptake, although it is the major species accumulated by the roots, both at pH 5 and pH 7. At pH 7, in contrast to pH 5, 10 micromolar DNP has no effect on ion permeability of barley roots yet it uncouples oxidative phosphorylation of barley root mitochondria. This indicates that the all too common use of DNP as a test for active transport or involvement of ATP synthesis can be misleading.DNP' is used often as an inhibitor to assess the extent to which a physiological process under study is "active" or involves ATP synthesis. DNP is well-known as an uncoupler of oxidative phosphorylation. However, it also increases cell membrane permeability to ions (4,15,18). The present work was undertaken to determine whether an inhibitor such as DNP is multifunctional. Inconsistency in the literature with respect to the concentration of DNP that is effective suggested that the effects of DNP on permeability may be those ofthe weak acid form. This is suggested also by effects on permeability of short chain aliphatic acids of which only the undissociated form is effective (14). Consequently, effects of DNP on the permeability of barley roots to ions were studied as a function of pH, concentration, and time. Effects of several other phenols were studied also, to assess the specificity of DNP effects on permeability. Uptake of 14C-labeled DNP was measured for comparison with the effects. MATERIALS AND METHODSThe roots were from 6-d-old seedlings of barley (Hordeum vulgare var. Trebi) which had been dark-grown in aerated 0.2 mm CaSO4 with or without 0.1 mM KCI at 22 to 25°C at pH 5.6. Roots were excised and rinsed several times with demineralized H20 just before the experiment. Roots

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Section: Discussionsupporting

confidence: 55%

Differences between Effects of Undissociated and Anionic 2,4-Dinitrophenol on Permeability of Barley Roots

Jackson

1982

Plant Physiol.

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“…The most obvious explanation for the observed dependence of conductance on concentration is that the exponent represents the number of monomers interacting to form a conducting unit, as has been suggested for the polyene antibiotics (Finkelstein & Cass, 1968), gramicidin A (Veatch et aZ., 1975) and many other carrier-type antibiotics. Such an explanation, attractive as it might seem, needs to be regarded cautiously in the light of the fact that co-operative (Cass et al, 1970) and other effects (Lea & Croghan, 1969;McLaughlin, 1972) between conducting units or subunits may influence their interpretation. Until detailed studies have been made of random fluctuations of current under voltage clamp, these suggestions remain speculative.…”

Section: Requirements Of Metal Salts For Cda Activitymentioning

confidence: 99%

A New Channel-forming Antibiotic from Streptomyces coelicolor A3(2) Which Requires Calcium for its Activity

Lakey¹,

Lea²,

Rudd³

et al. 1983

Microbiology

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A recently discovered antibiotic (CDA ; calcium-dependent antibiotic) of Streptomyces coelicolor A3(2) was found to be effective against a wide range of Gram-positive bacteria only in the presence of calcium ions. Producer and non-producer strains were identified and several media tested for their ability to support antibiotic production. The action of calcium was not simulated by any of the other cations tested. The antibiotic was found to induce discrete conductance fluctuations in planar lipid bilayer consistent with a channel-forming action. The electrical potential difference caused by a concentration difference of various salts across the CDAcontaining bilayer, showed the channel to be cation-selective but of a size that discriminated against tetramethyl ammonium and choline ions. The data indicate that the antibiotic activity of CDA is due to its action as a calcium-dependent ionophore.

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“…The electrical potential (At) together with the difference in proton concentration between the periplasm and cytoplasm (zApH) make up the proton motive force, which is typically maintained at a steady-state value of -150 to -200 mV (14). Ap is harnessed to drive nutrient transport, ATP synthesis, and other endergonic reactions at the cell membrane.Uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), are able to transport protons across biological membranes, which usually have extremely low proton conductance (16,17). By transporting protons down the electrochemical potential gradient, these agents collapse Ap.…”

mentioning

confidence: 99%

“…Uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), are able to transport protons across biological membranes, which usually have extremely low proton conductance (16,17). By transporting protons down the electrochemical potential gradient, these agents collapse Ap.…”

mentioning

confidence: 99%

Adaptation of Escherichia coli to the uncoupler of oxidative phosphorylation 2,4-dinitrophenol

Gage

Neidhardt

1993

J Bacteriol

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Escherichia coli was found to adapt to the uncoupler of oxidative phosphorylation 2,4-dinitrophenol. The rates of synthesis of 53 proteins were increased following exposure to 2,4-dinitrophenol. Adaptation was accelerated when the cofactor pyrroloquinoline quinone was provided in the growth medium.In Escherichia coli, energy associated with the oxidation of an energy source is conserved as an electrochemical potential difference of hydrogen ions across the cytoplasmic membrane and is termed the proton motive force (Ap). The electrical potential (At) together with the difference in proton concentration between the periplasm and cytoplasm (zApH) make up the proton motive force, which is typically maintained at a steady-state value of -150 to -200 mV (14). Ap is harnessed to drive nutrient transport, ATP synthesis, and other endergonic reactions at the cell membrane.Uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), are able to transport protons across biological membranes, which usually have extremely low proton conductance (16,17). By transporting protons down the electrochemical potential gradient, these agents collapse Ap. The collapse of Ap has detrimental effects on the bacterial cell: (i) the rate of proton-coupled ATP synthesis declines; (ii) the pH of the cytoplasm, typically maintained near 7.8 (3), approaches that of the external medium (8); and (iii) nutrient transport is inhibited, as is the translocation of proteins destined for insertion into the cytoplasmic membrane (1, 7, 10).Here we show that wild-type E. coli is able to adapt to the uncoupler of oxidative phosphorylation DNP and that the rate of adaptation is accelerated by the cofactor pyrroloquinoline quinone (PQQ). In addition, we show that E. coli induces approximately 50 proteins, including the heat shock proteins, upon exposure to DNP. E. coli adapts to DNP. E. coli W3110 growing in glucose-rich morpholinepropanesulfonic acid (MOPS) medium (GRM) without methionine (9) at 28°C was exposed to 0.5, 0.75, and 1.0 mM DNP. Following challenge with these concentrations of DNP, there were immediate cutbacks in the growth rate of 45, 75, and 90%, respectively (Fig. 1). Following the cutback in growth rate, cultures exposed to 0.5 and 0.75 mM DNP increased their growth rates and nearly reached the rate at which they grew before exposure to DNP. The growth rate of the culture exposed to 1.0 mM DNP increased somewhat but never reached the pre-DNP growth rate. A similar growth response has been noted when E. coli is exposed to inhibitory concentrations of CCCP (18 (Fig. 2). PQQ did not increase the growth rate of a culture growing in medium without DNP, indicating that PQQ did not act as a general growth enhancer. It was shown that glucose dehydrogenase, and not some other enzyme which utilizes PQQ as a cofactor, was responsible for the accelerated adaptation to DNP by conducting the same experiment using isogenic strain DG300 (gcd::cat), which contains a chloramphenicol resistan...

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The mechanism of action of DNP on phospholipid bilayer membranes

Cited by 122 publications

References 19 publications

Differences between Effects of Undissociated and Anionic 2,4-Dinitrophenol on Permeability of Barley Roots

Differences between Effects of Undissociated and Anionic 2,4-Dinitrophenol on Permeability of Barley Roots

A New Channel-forming Antibiotic from Streptomyces coelicolor A3(2) Which Requires Calcium for its Activity

Adaptation of Escherichia coli to the uncoupler of oxidative phosphorylation 2,4-dinitrophenol

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