Specific ion effects on the growth rates of<i>Staphylococcus aureus</i>and<i>Pseudomonas aeruginosa</i>

Nostro, Pierandrea Lo; Ninham, Barry W.; Nostro, Antonella Lo; Pesavento, Giovanna; Fratoni, Laura; Baglioni, Piero

doi:10.1088/1478-3967/2/1/001

Cited by 107 publications

(98 citation statements)

References 46 publications

(64 reference statements)

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“…Therefore, at the interface, ionic polarization, ionic distribution and the electric field are interwined. At the solid/liquid interface, however, we often meet strong electric field greater than 10 8 V/m, the effects observed by Noah-Vanhoucke and Geissler might be much stronger and much more complex.…”

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confidence: 81%

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Strong non-classical induction forces in ion-surface interactions: General origin of Hofmeister effects

Liu

et al. 2014

Sci Rep

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Hofmeister effects continue to defy all-encompassing theories, and their origin is still a matter of debate. We observed strong Hofmeister effects in Ca 21 /Na 1 exchange on a permanently charged surface over a wide range of ionic strengths. They could not be attributed to dispersion forces, classical induction forces, ionic size, or hydration effects. We demonstrated that another stronger force was active in the ion-surface interactions, and which would create Hofmeister effects in general. The strength of this force was up to 10 4 times that of the classical induction force, and could be comparable to the Coulomb force. Coulomb, dispersion and hydration effects appeared to be interwined to affect the force. The presence of the observed strong non-classical induction force implied that energies of non-valence electrons of ions/atoms at the interface might be heavily underestimated in current theories, and possibly just those underestimated energies of non-valence electrons determined Hofmeister effects. Hofmeister effects, also known as specific ion effects, were observed over 120 years ago. Even though they are ubiquitous in the physical, chemical and biological literature, their origin is still contested 1-7 and has been recently brought to the forefront of research [8][9][10][11][12][13][14][15][16][17][18][19] . New work in this area may break down barriers between physics and biology 9 . Ionic sizes, hydration, quantum fluctuations (or dispersion forces) 3,4,8 , and surface charges 1,2 are crucial in Hofmeister effects. Nano-scale surfaces and colloidal particles (e.g., DNA, proteins, cells, bacteria, metal oxides, and clay) are usually strongly charged in aqueous solution, and the sign of the charge or the charge number for biological macromolecules will be dependent on pH and ionic strength 20 . In classical theory, the surface charges can set up a strong electric field extending from the surface to several nanometers in solution. Typical surface charge densities and their corresponding electric field strengths include: (1) . For proteins, surface charge density measurements are primarily based on zeta potentials; therefore, they would be equal to the charge density at the shear plane, which is possibly much lower than the charge density at the surface [27][28][29] , especially when considering the strong surface hydration force [30][31][32] . At the shear plane, the charge density could reach 0.02-0.35 C/m 2 [33][34][35] , with an electric field of 10 7 -10 8 V/m. Therefore, it is reasonable to expect electric field strengths .10 8 V/m at protein surfaces in aqueous solutions. However, in those calculations, adsorbed counter-ions near the surface are treated as point charges. If their ionic size were taken into account, then the electric field near the surface would be much greater than 10 8 V/ m. This is because the finite size of counter ions could weaken their screening effect, as compared with point charges.Noah-Vanhoucke and Geissler found that, the persistence of electric field in the space near ...

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confidence: 81%

“…Even though they are ubiquitous in the physical, chemical and biological literature, their origin is still contested 1-7 and has been recently brought to the forefront of research [8][9][10][11][12][13][14][15][16][17][18][19] . New work in this area may break down barriers between physics and biology 9 .…”

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confidence: 99%

Strong non-classical induction forces in ion-surface interactions: General origin of Hofmeister effects

Liu

et al. 2014

Sci Rep

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“…Maintaining a delicate balance of ions, biomembranes interact preferentially with different ionic species (1). Specific ionic effects have been shown to influence the growth rates of bacteria (2) and fungi (3,4) and to affect the function of antibiotic channels (5). This investigation will focus on the halide salts because of their presence in intracellular and intercellular fluids.…”

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confidence: 99%

Swelling of phospholipids by monovalent salt

Petrache

Tristram-Nagle

Harries

et al. 2006

Journal of Lipid Research

152

158

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Critical to biological processes such as membrane fusion and secretion, ion-lipid interactions at the membranewater interface still raise many unanswered questions. Using reconstituted phosphatidylcholine membranes, we confirm here that multilamellar vesicles swell in salt solutions, a direct indication that salt modifies the interactions between neighboring membranes. By varying sample histories, and by comparing with data from ion carrier-containing bilayers, we eliminate the possibility that swelling is an equilibration artifact. Although both attractive and repulsive forces could be modified by salt, we show experimentally that swelling is driven primarily by weakening of the van der Waals attraction. To isolate the effect of salt on van der Waals interactions, we focus on high salt concentrations at which any possible electrostatic interactions are screened. By analysis of X-ray diffraction data, we show that salt does not alter membrane structure or bending rigidity, eliminating the possibility that repulsive fluctuation forces change with salt. By measuring changes in interbilayer separation with applied osmotic stress, we have determined, using the standard paradigm for bilayer interactions, that 1 M concentrations of KBr or KCl decrease the van der Waals strength by 50%. By weakening van der Waals attractions, salt increases energy barriers to membrane contact, possibly affecting cellular communication and biological signaling. From bacteria to mammals, biological processes take place in salt solutions. Maintaining a delicate balance of ions, biomembranes interact preferentially with different ionic species (1). Specific ionic effects have been shown to influence the growth rates of bacteria (2) and fungi (3,4) and to affect the function of antibiotic channels (5). This investigation will focus on the halide salts because of their presence in intracellular and intercellular fluids. At biomembrane surfaces, halides encounter not only charged lipid species, such as phosphatidylserine and phosphatidylinositol, but more often common neutral phosphatidylcholines (PCs). Interactions with both types of lipids require investigation: by affecting lipid interactions, salt solutions modulate biological processes such as fusion and secretion.Despite being electrically neutral, PC membranes attract one another as a result of mutually induced charge fluctuations (6). Because of different dielectric properties of membranes and the intervening solvent, transient spontaneous electromagnetic fields in one membrane induce correlated fields in the neighboring membrane and vice versa, resulting in an attractive force. This "charge fluctuation" (van der Waals) force is responsible for the spontaneous formation of stable multilamellar structures [e.g., myelin sheets in vivo and multilamellar vesicles (MLVs) in vitro]. When the attractive van der Waals force is exactly balanced by repulsive forces, an equilibrium spacing between lamellae is established (6-9). Typically, as measured by small-angle X-ray scattering, the...

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“…The original lyotropic series was discovered by studying the ability of different ions to precipitate or stabilize protein solutions [2][3][4]. Following the pioneering work of Hofmeister, the same series has been observed in many other areas of science, ranging from electrochemistry, colloidal science [5,6], surfactant micellization [7], bacterial growth [8], surface and interfacial tensions [9,10], peptide bonds [11], microemulsions [12], etc. Recently, a theory was proposed that allows one to quantitatively predict the effect of Hofmeister ions on the surface [13][14][15] and the interfacial tensions [16,17] of electrolyte and acid solutions.…”

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confidence: 93%

Adsorption of cationic polyions onto a hydrophobic surface in the presence of Hofmeister salts

Santos

Levin

2013

Soft Matter

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We study, using extensive Monte Carlos simulations, the behavior of cationic polyelectrolytes near hydrophobic surfaces in solutions containing Hofmeister salts. The Hofmeister anions are divided into kosmotropes and chaotropes. Near a hydrophobic surface, the chaotropes lose their solvation sheath and become partially adsorbed to the interface, while the kosmotropes remain strongly hydrated and are repelled from the interface. If the polyelectrolyte solution contains chaotropic anions, a significant adsorption of polyions to the surface is also observed. On the other hand, the kosmotropic anions have only a small influence on the polyion adsorption. These findings can have important implications for exploring the antibacterial properties of cationic polyelectrolytes.

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Specific ion effects on the growth rates ofStaphylococcus aureusandPseudomonas aeruginosa

Cited by 107 publications

References 46 publications

Strong non-classical induction forces in ion-surface interactions: General origin of Hofmeister effects

Strong non-classical induction forces in ion-surface interactions: General origin of Hofmeister effects

Swelling of phospholipids by monovalent salt

Adsorption of cationic polyions onto a hydrophobic surface in the presence of Hofmeister salts

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