I<scp>ONIC</scp> E<scp>FFECTS</scp> B<scp>EYOND</scp> P<scp>OISSON</scp>-B<scp>OLTZMANN</scp> T<scp>HEORY</scp>

Vlachy, Vojko

doi:10.1146/annurev.physchem.50.1.145

Cited by 212 publications

(148 citation statements)

References 99 publications

Supporting

Mentioning

146

Contrasting

Order By: Relevance

“…This rendered DLVO theory inadequate [39,40]. Although monovalent ions in solution might be represented by a continuum characterized by a Debye screening length, κ À 1 , this approach cannot be used to describe divalent cations because the latter can take part in bridging between negatively-charged molecular moieties [41].…”

Section: Mathematical Models and Computer Simulation Theory And Mathementioning

confidence: 99%

“…The aqueous solutions (z < À z HC /2) and (z > z HC /2), and the hydrocarbon-chain region (Àz HC /2 < z < z HC /2), were represented as two dielectric continua with relative permittivities ε w = 81 and ε HC = 5, respectively [38], and we represented the part of the monovalent ion screening in the aqueous solution by linearized Poisson-Boltzmann theory [36,38,41,45,46]. We represented the remainder of the monovalent ions by explicit ions.…”

Section: Electrostatic Interactionsmentioning

confidence: 99%

See 1 more Smart Citation

Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa

Pink

Hasan

Quinn

et al. 2014

Journal of Peptide Science

View full text Add to dashboard Cite

This study was concerned with the interaction between the cationic antimicrobial peptide, protamine (Ptm) and the cytoplasmic membranes of the gram-negative bacteria Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa. The objective of the study was to explain the observed paradox of internalization without permanent disruption of the cell envelope. We carried out Monte Carlo computer simulation of Ptm in an aqueous environment in the presence of~100 mM NaCl and model membranes consisting of either (65:35) or (75:25) PE:PG molar ratios. The (75:25) model, representative of the gram-negative cytoplasmic membrane, showed that the Ptm center of mass remained at least 7 nm from the membrane surface leading to the prediction that Ptm would not internalize via disruption of the inner membrane.By using immunoelectron microscopy of Ptm-treated cells, we showed that Ptm internalization to the cytoplasm took place rapidly in the presence or absence of the outer envelope. Ultrastructural examination revealed no obvious morphological changes to cells that were treated with subinhibitory or bactericidal levels of Ptm. Reconstituted phospholipid bilayers were constructed and were unperturbed by Ptm treatment over a wide range of concentrations and applied transmembrane voltages. We conclude that in the cases of the cell envelopes of E. coli, S. typhimurium and P. aeruginosa, Ptm internalized by means independent of the phospholipid bilayer, most likely mediated by one or more membrane proteins such as cation-selective barrel-like proteins. Work is currently underway to test this hypothesis.

show abstract

Section: Mathematical Models and Computer Simulation Theory And Mathementioning

confidence: 99%

Section: Electrostatic Interactionsmentioning

confidence: 99%

Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa

Pink

Hasan

Quinn

et al. 2014

Journal of Peptide Science

View full text Add to dashboard Cite

show abstract

“…The role of counterion correlations has been extensively studied by various means, including integral equation theories and molecular simulations starting from eighties [4,6,7,8,9,10,11] and is currently well understood [2,3,4,6,7]. In contrast, macroion correlation effects are usually not included in the mean-field approaches and therefore not quantified.…”

Section: Introductionmentioning

confidence: 99%

Macroion correlation effects in electrostatic screening and thermodynamics of highly charged colloids

et al. 2006

View full text Add to dashboard Cite

We study macroion correlation effects on the thermodynamics of highly charged colloidal suspensions using a mean-field theory and primitive model computer simulations. We suggest a simple way to include the macroion correlations into the mean-field theory as an extension of the renormalized jellium model of Trizac and Levin [Phys. Rev. E 69, 031403 (2004)]. The effective screening parameters extracted from our mean-field approach are then used in a one-component model with macroions interacting via Yukawa-like potential to predict macroion distributions. We find that inclusion of macroion correlations leads to a weaker screening and hence smaller effective macroion charge and lower osmotic pressure of the colloidal dispersion as compared to other mean-field models. This result is supported by a comparison to primitive model simulations and experiments for charged macroions in the low-salt regime, where the macroion correlations are expected to be significant.

show abstract

“…When the charged particles are described as charged hard spheres and the solvent as a dielectric continuum, one speaks of the primitive model [3]. The pair distribution functions (PDFs) of the colloidal particles are experimentally accessible, either through scattering experiments [4,5] or by direct observation in real space.…”

Section: Introductionmentioning

confidence: 99%

Macroion shielding and state-dependent pair potentials in colloidal suspensions

Klein

Grünberg

Bechinger

et al. 2002

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We determine radial distribution functions for charge-stabilized colloidal suspensions for various volume fractions. By means of two independent inversion routines based on (i) the Ornstein-Zernike equation and (ii) the inverse Monte Carlo method, we extract effective colloid-colloid pair potentials from the distribution functions. Working at a fixed salinity, these potentials would not depend on the colloid density if the interactions between the colloids were purely pairwise additive. Our potentials however show a density dependence; agreement with the Yukawa form of DLVO (Derjaguin-Landau-VerweyOverbeek) theory is found only at low densities, but not at high densities. Such a state dependence of pair potentials reveals the density-dependent impact of many-body terms in the total interaction energy of the system. We also perform primitive model calculations, with parameters simulating our experiment, and find qualitatively similar deviations of the effective pair potentials from the Yukawa form, which thus confirms our experimental findings. Using results from a calculation of three-body interactions in colloidal suspensions, we are able to trace the observed density dependence of the pair potentials back to a shielding effect of the macroions. This interpretation is consistent with other experimental studies observing attractive parts in the pair potentials which were interpreted as 'like-charge attraction'. Our results, however, suggest that this attraction is a many-body effect.

show abstract

IONIC EFFECTS BEYOND POISSON-BOLTZMANN THEORY

Cited by 212 publications

References 99 publications

Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa

Interaction of protamine with gram‐negative bacteria membranes: possible alternative mechanisms of internalization in Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa

Macroion correlation effects in electrostatic screening and thermodynamics of highly charged colloids

Macroion shielding and state-dependent pair potentials in colloidal suspensions

Contact Info

Product

Resources

About