Intrinsic perturbing ability of alkanols in lipid bilayers

Jain, Mahendra Kumar; Gleeson, John P.; Upreti, Akhanda Raj; Upreti, G.C.

doi:10.1016/0005-2736(78)90002-0

Cited by 85 publications

(34 citation statements)

References 12 publications

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“…It was shown in earlier papers (Haydon et al 1977;Haydon & Hendry, 1982) that the cut-off in potency found for n-alkanes in the range n-pentane to n-decane correlates with a decrease in adsorption to a lecithin-cholesterol bilayer. It is consistent therefore that the absence of a cut-off for the n-alkanols up to n-decanol is paralleled by the maintained adsorption in this range (Hill, 1974;Jain, Gleeson, Upreti & Upreti, 1978;Kamaya, Kaneshina & Ueda, 1981). Partitioning between aqueous solution -3.11* Kamaya, Kaneshina & Ueda (1981) and dimyristoyl-, dipalmitoyl-and distearoylphosphatidylcholine Adsorption at n-dodecane-aqueous -3.12* Mitchell (1969) solution interface Aveyard & Haydon (1973) Blockage of the propagated action -2-88* Calculated from data in Seeman potential in sciatic nerve (1972).…”

Section: Resultssupporting

confidence: 58%

The action of alcohols and other non‐ionic surface active substances on the sodium current of the squid giant axon.

Haydon¹,

Urban²

1983

The Journal of Physiology

103

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SUMMARY1. The effects of several n-alkanols and n-alkyl oxyethylene alcohols, methyl octanoate, glycerol 1-monooctanoate and dioctanoyl phosphatidylcholine on the ionic currents and electrical capacity of the squid giant axon membrane have been examined.2. The peak inward current in voltage-clamped axons was reduced reversibly by each substance.3. For n-pentanol to n-decanol the concentrations required to suppress the peak inward current by 50 % were determined. From these data, it was estimated that the standard free energy per CH2 for adsorption to the site of action was -3 04 kJ mole-', as compared with -3-11 kJ mole-' for adsorption into phospholipid bilayers or an n-alkane/aqueous solution interface. 4. The membrane capacity at 100 kHz was not greatly affected by any of the test substances at concentrations which reduced the inward current by 50 %.5. Na currents under voltage clamp were recorded in intracellularly perfused axons before, during and sometimes after exposure to the test substances and the records were fitted with equations similar to those proposed by Hodgkin & Huxley (1952).6. Shifts in the curves of the steady-state activation and inactivation parameters (mo and h.o) against membrane potential, changes in the peak heights of the activation and inactivation time constants (Tm and Th) and reductions in the maximum Na conductance (gNa) have been tabulated.7. All of the test substances shifted the voltage dependence of the steady-state activation in the depolarizing direction and lowered the peak time constants for both activation and inactivation. The origins of these effects, and of the differences in the present results from those of the hydrocarbons (Haydon & Urban, 1983), have been discussed in terms of the physico-chemical properties of the two groups of substances and with reference to their effects on artificial membranes.

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Section: Resultssupporting

confidence: 58%

The action of alcohols and other non‐ionic surface active substances on the sodium current of the squid giant axon.

Haydon¹,

Urban²

1983

The Journal of Physiology

103

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“…The action of phospholipases on a phospholipid bilayer, for example, is facilitated by long chain alcohols [6]. In previous publications we reported: that the effect of these alcohols depends upon their concentrations [6] and chain length [7] ; that the activating effect of hexanol is due to a modification of the bilayer rather than the solubilization of the substrate [23]; that the optimal activating effect of hexanol is observed when the hexanol to phospholipid mole ratio in the bilayer is ~ 1.3 [23]; that the ability of alcohols to perturb the gel phase in dipalmitoylphosphatidylcholine bilayer correlates well with their ability to activate the phospholipase A z catalyzed hydrolysis of egg phosphatidylcholine bilayer [8]; and the behavior of the alkanol modified bilayer is compar- …”

mentioning

confidence: 83%

Intrinsic differences in the perturbing ability of alkanols in bilayer: Action of phospholipase A2 on the alkanol-modified phospholipid bilayer

1980

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The kinetic parameters for the steady-state rate of hydrolysis of egg phosphatidylcholine in multilamellar vesicles by bee venom phospholipase A2 are measured in the presence of 27 alkanols and several organic solvents. In general, small nonpolar solutes like enflurane, tetrahydrofuran, benzene, chloroform and diethylether do not promote the hydrolysis of multilamellar vesicles. The rate of hydrolysis shows a biphasic dependence upon the alkanol concentration for all higher (C5-C9) alcohols examined, i.e., an optimal rate of hydrolysis is observed at a characteristic concentration for each alcohol. The alkanol to lipid mole ratio (D/L ratio) in the bilayer at the peak activating concentration of an alkanol was computed from its bilayer/water partition coefficient. The branched chain alcohols induce peak activation of hydrolysis at lower D/L ratios in the bilayer than the corresponding straight chain analogs. Similarly, the longer chain n-alkanols at peak activating concentration have a lower D/L ratio than the corresponding lower alcohols. Both the Km and Vm for phosphatidylcholine increase as a function of the chain length of the activating alcohol. These kinetic parameters also depend upon the position of the substituents on the activating alcohols. Both the D/L ratio and Vm for an alcohol are found to change with the cross-sectional area of the activating alcohol across its long axis: alcohols with a more asymmetric cross-section exhibit higher Vm and a lower D/L ratio. Such correlations of Vm and D/L ratio with the molecular parameters of the alkanols are interpreted to suggest that the accessibility of the substrate molecule in the bilayer to the phospholipase is modulated by the free space introduced by the alkanols in the bilayer. Effect of tetradecane derivatives and A2C (a membrane fluidizing agent) on the phase transition characteristics of DPPC bilayers, and their susceptibility to phospholipase A2 from bee venom and pig pancreas is also reported. These solutes cause a broadening of the transition profile and reduce the size of the cooperative unit and the enthalpy of transition. These effects depend upon the mole fraction of a solute in the bilayer; however, equal concentrations of these solutes do not induce equal response. Susceptibility of the modified bilayers to phospholipase A2 depends not only upon the structure of the solute but also upon the source of the enzyme. The data show that the activity of the membrane-bound enzyme is modulated to different extents by different solutes, and the bilayer perturbing ability of these solutes may be related to the asymmetry of their cross-sectional area and to the free space introduced by the alkanols in a bilayer.

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“…Fundamental work on the impact of alcohols and ketones on Escherichia coli showed that the intercalation of solvents within the lipid bilayer increases membrane fluidity (21) and also affects lipid-protein interactions integral to membrane function (22,23). The microbial response to perturbations in membrane fluidity, or "homeoviscous adaptation," has been studied extensively with regard to the response of E. coli to temperature upshifts, a stress phenomenon with an impact on membrane fluidity similar to that of solvent toxicity (44).…”

mentioning

confidence: 99%

Dynamics of Genomic-Library Enrichment and Identification of Solvent Tolerance Genes for Clostridium acetobutylicum

Borden

Papoutsakis

2007

Appl Environ Microbiol

175

107

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A Clostridium acetobutylicum ATCC 824 genomic library was constructed using randomly sheared DNA. Library inserts conferring increased tolerance to 1-butanol were isolated using two protocols. Protocol I utilized a single round of butanol challenges in batch culture, while protocol II, which gave clearly superior outcomes, was based on the serial transfer of stationary-phase cultures into progressively higher butanol concentrations. DNA microarray analysis made a high-resolution assessment of the dynamic process of library enrichment possible for the first time. Protocol I yielded a library insert containing the entire coding region of the gene CAC0003 (which codes for a protein of unknown function) but also several DNA fragments containing promoter regions. Protocol II enabled the successful identification of DNA fragments containing several intact genes conferring preferential growth under conditions of butanol stress. Since expression using the employed library is possible only from natural promoters, among the enriched genes, we identified 16 genes that constitute the first cistron of a transcriptional unit. These genes include four transcriptional regulators (CAC0977, CAC1463, CAC1869, and CAC2495). After subcloning plasmids carrying the CAC0003 and CAC1869 genes, strains 824(pCAC0003) and 824(pCAC1869) exhibited 13% and an 81% increases, respectively, in butanol tolerance relative to the plasmid control strain. 824(pCAC1869) consistently grew to higher cell densities in challenged and unchallenged cultures and exhibited prolonged metabolism. Our serial enrichment approach provided a more detailed understanding of the dynamic process of library enrichment under conditions of selective growth. Further characterization of the genes identified in this study will likely enhance our understanding of the complex phenotype of solvent tolerance.

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Intrinsic perturbing ability of alkanols in lipid bilayers

Cited by 85 publications

References 12 publications

The action of alcohols and other non‐ionic surface active substances on the sodium current of the squid giant axon.

The action of alcohols and other non‐ionic surface active substances on the sodium current of the squid giant axon.

Intrinsic differences in the perturbing ability of alkanols in bilayer: Action of phospholipase A2 on the alkanol-modified phospholipid bilayer

Dynamics of Genomic-Library Enrichment and Identification of Solvent Tolerance Genes for Clostridium acetobutylicum

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