Influence of metal ions on the phase properties of phosphatidic acid in combination with natural and synthetic phosphatidylcholines: an x-ray diffraction study using synchrotron radiation

Caffrey, Martin; Feigenson, Gerald W.

doi:10.1021/bi00297a023

Cited by 45 publications

(39 citation statements)

References 46 publications

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“…1) in the presence of EPA, evident in the gel phase. In our experi-37 mental conditions a complete miscibility of DMPC and EPA is suggested by anisotropy data, in agreement with Caffrey and Feigenson [25]. As for DPH, TMA-DPH fluorescence decay requires at least two exponentials for adequate description.…”

Section: Discussionsupporting

confidence: 85%

“…4). The anisotropy values for DMPC/EPA show that in the mixture, the transition was shifted to lower temperature and the transition range was broader (15--22°C) in agreement with data reported by Caffrey and Feigenson [25]. Moreover, above and below the DMPC/EPA transition, the anisotropy was higher than that observed in the corresponding phases for pure DMPC.…”

Section: Tma-dph Fluorescence In Dmpc and Dmpc/epa Liposomessupporting

confidence: 89%

“…4, I), but a clear separation between pre-and main transition is not possible. In a similar system, Caffrey and Feigenson [25] demonstrated by X-ray diffraction that the phase separation was minimal, suggesting a high degree of miscibility between the two lipids.…”

Section: Tma-dph Fluorescence In Dmpc and Dmpc/epa Liposomesmentioning

confidence: 92%

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Phosphatidic acid affects structural organization of phosphatidylcholine liposomes. A study of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammonium-phenyl)-6-phenyl,1,3,5-hexatriene (TMA-DPH) fluorescence decay using distributional analysis

Zolese

Gratton

Curatola

1990

Chemistry and Physics of Lipids

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Section: Discussionsupporting

confidence: 85%

Section: Tma-dph Fluorescence In Dmpc and Dmpc/epa Liposomessupporting

confidence: 89%

See 1 more Smart Citation

Phosphatidic acid affects structural organization of phosphatidylcholine liposomes. A study of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammonium-phenyl)-6-phenyl,1,3,5-hexatriene (TMA-DPH) fluorescence decay using distributional analysis

Zolese

Gratton

Curatola

1990

Chemistry and Physics of Lipids

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“…Furthermore, addition of NaCl reduced the T m of the cell membrane and increased the pressure required to induce a phase transition from the liquid crystalline phase to the gel phase. Monovalent cations do not affect the phase properties of phospholipid bilayers (6). Therefore, the protective effect of NaCl on the cell membrane of L. lactis must be attributed to the presence of compatible solutes accumulated intracellularly.…”

Section: Discussionmentioning

confidence: 94%

Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

Molina-Höppner

Doster

Vogel

et al. 2004

Appl Environ Microbiol

172

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The bactericidal effect of hydrostatic pressure is reduced when bacteria are suspended in media with high osmolarity. To elucidate mechanisms responsible for the baroprotective effect of ionic and nonionic solutes, Lactococcus lactis was treated with pressures ranging from 200 to 600 MPa in a low-osmolarity buffer or with buffer containing 0.5 M sucrose or 4 M NaCl. Pressure-treated cells were characterized in order to determine viability, the transmembrane difference in pH (⌬pH), and multiple-drug-resistance (MDR) transport activity. Furthermore, pressure effects on the intracellular pH and the fluidity of the membrane were determined during pressure treatment. In the presence of external sucrose and NaCl, high intracellular levels of sucrose and lactose, respectively, were accumulated by L. lactis; 4 M NaCl and, to a lesser extent, 0.5 M sucrose provided protection against pressure-induced cell death. The transmembrane ⌬pH was reversibly dissipated during pressure treatment in any buffer system. Sucrose but not NaCl prevented the irreversible inactivation of enzymes involved in pH homeostasis and MDR transport activity. In the presence 0.5 M sucrose or 4 M NaCl, the fluidity of the cytoplasmic membrane was maintained even at low temperatures and high pressure. These results indicate that disaccharides protect microorganisms against pressure-induced inactivation of vital cellular components. The protective effect of ionic solutes relies on the intracellular accumulation of compatible solutes as a response to the osmotic stress. Thus, ionic solutes provide only asymmetric protection, and baroprotection with ionic solutes requires higher concentrations of the osmolytes than of disaccharides.The accumulation of compatible solutes, such as betaines, proline, and sugars, is a widespread response of microorganisms to elevated environmental osmotic pressures (41). According to a recent definition, a compatible solute is a "cytoplasmic cosolvent (solute) whose levels can be modulated over a broad range without disrupting cellular function" (24, 43). Compatible solutes contribute to the osmotic balance with the extracellular environment, enhance the stability of enzymes, and preserve the integrity of biological membranes (41). The composition of the osmolytes that are accumulated depends on the type of osmotic shock (i.e., ionic stress versus nonionic stress) and the presence of specific compatible solutes in the medium. In addition to their role as osmotic balancers, compatible solutes provide protection against high temperature, freeze-thaw treatment, and drying (41, 43).When the osmotic pressure of the medium is increased, the tolerance of microorganisms to high hydrostatic pressure is enhanced. Baroprotective effects of sodium chloride or sugars have been observed in studies with Escherichia coli, Saccharomyces cerevisiae, Zygosaccharomyces spp., and Rhodoturula rubra (14,17,24,25,36). The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotectiv...

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“…Differential scanning calorimetry (DSC) measurements revealed that the phase-transition temperature of the DPPC vesicles (T c 38 8C) [12] was not influenced by incorporation of Rh-5 and Mn-1 (vide infra).…”

Section: Resultsmentioning

confidence: 99%

A Supramolecular Cytochrome P450 Mimic

et al. 1998

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An amphiphilic rhodium(iii) complex has been incorporated in closed bilayers of surfactants with positive, zwitterionic, or negative charges. In the presence of formate this rhodium complex efficiently catalyzes the reduction of a variety of electron carriers and manganese(iii) porphyrins. The charge of the surfactant head groups determines the acidity of the reduced Rh III hydride complex and the rate of reduction, which increases on going from negatively to positively charged surfactants. A manganese(iii) porphyrin, incorporated in the bilayers together with the Rh complex, can be used as an artificial cytochrome P450-type epoxidation catalyst. The relative concentrations of Mn II and Mn III porphyrin depend on the reduction and reoxidation rates, and an oscillating reaction is observed at a Rh complex/Mn porphyrin ratio of 10. A variety of substrates are epoxidized by reductive activation of O 2 by this model system with turnover numbers of the same order of magnitude as those of the enzyme system. The charge on the surfactant has a dramatic effect on the catalytic epoxidation activity of the model system. Aggregates of positively charged surfactant molecules do not display catalytic activity in this reaction, probably because the protons required for cleavage of the oxygen ± oxygen bond are repelled at the aggregate surface.

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Influence of metal ions on the phase properties of phosphatidic acid in combination with natural and synthetic phosphatidylcholines: an x-ray diffraction study using synchrotron radiation

Cited by 45 publications

References 46 publications

Phosphatidic acid affects structural organization of phosphatidylcholine liposomes. A study of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammonium-phenyl)-6-phenyl,1,3,5-hexatriene (TMA-DPH) fluorescence decay using distributional analysis

Phosphatidic acid affects structural organization of phosphatidylcholine liposomes. A study of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammonium-phenyl)-6-phenyl,1,3,5-hexatriene (TMA-DPH) fluorescence decay using distributional analysis

Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

A Supramolecular Cytochrome P450 Mimic

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