Hydration of Escherichia coli lipids

Borle, François; Seelig, Joachim

doi:10.1016/0005-2736(83)90268-7

Cited by 62 publications

(31 citation statements)

References 13 publications

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“…Small variations in the number of water molecules present at the glycerol backbone can determine significant variations in the emission of Laurdan, especially if the average number of water molecules is small. NMR studies show that the average number of free water molecules at the glycerol backbone of phosphocholine membranes is small and between 2 and 6 [52–55]. When the temperature is decreased towards the phase transition, the average number of water molecules surrounding the dye decreases due to the average increase in lipid density.…”

Section: Resultsmentioning

confidence: 99%

Dynamics of lipid domain formation: Fluctuation analysis

Celli

Gratton²

2010

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Summary Scanning-fluctuation correlation spectroscopy was used to detect sub resolution organizational fluctuations in the lipid liquid-crystalline phase for single lipid model systems. We used the fluorescent probe Laurdan which is sensitive to the amount of water in the membrane to show that there is a spatial heterogeneity on the scale of few pixels (the size of the pixel is 50 nm). We calculated the pixel variance of the GP function and we found that the variance has a peak at the phase transition for 3 different samples made of pure lipids. The pixel variance has an abrupt change at the phase transition of the membrane and then it slowly decreases at higher temperature. The relatively large variance of the GP indicates that the liquid phase of the membrane is quite heterogeneous even several degrees higher than the phase transition temperature. We interpreted this result as evidence of an underlying micro scale structure of the membrane in which water is not uniformly distributed at the micron scale. Imaging of these microstructures shows that the pixels with different GP tend to concentrate in specific domains in the membrane. In the case of single lipid membrane, the statistical and fluctuation analysis of the GP data shows that even such simple lipid systems are capable of generating and maintaining stable structural and organizational heterogeneities.

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Section: Resultsmentioning

confidence: 99%

Dynamics of lipid domain formation: Fluctuation analysis

Celli

Gratton²

2010

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…Second, the change in electrostriction of water molecules around the carbonyl group and polar head group of DPPC molecules can have a marked effect on the volume change (AV2t). It should be noted that the headgroup bound H20 molecules are not icelike immobilized molecules (Borle and Seelig, 1983). Although they are more compactly packed around the lipid dipolar head group due to electrostriction, these bound water molecules are in constant exchange with the interstitial water located between the lipid lamellae.…”

Section: Discussionmentioning

confidence: 99%

Pressure effect on the rate of crystalline phase formation of L-alpha-dipalmitoylphosphatidylcholines in multilamellar dispersions

Wu¹,

Chong²,

Huang³

1985

Biophysical Journal

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Fully hydrated dipalmitoylphosphatidylcholine (DPPC) in multilamellar dispersions undergoes a subtransition between the crystalline Lc phase and the gel L beta phase. This so-called subtransition occurs only if the DPPC-H2O system has been incubated at temperatures near 0 degrees C for an extended period. We have examined the effect of pressure, up to 336 atm, on the rate of crystalline Lc phase formation of multilamellar DPPC dispersions at 0 degrees C. The hydrostatic pressure is generated by a centrifugal field; the formation of the lamellar Lc phase in the multicomponent DPPC dispersions is monitored calorimetrically at ambient pressure. Results indicate that the rate of formation of the hydrated crystalline Lc phase decreases with increasing pressure. Based on transition state theory, the retardation of the formation of the hydrated crystalline Lc phase by pressure is due to an increase in the volume of the lipid-water system when the activated state is formed. We interpret that the positive value of activation volume is attributed primarily to the dehydration of the lipid polar head group. Although the acyl chain ordering and the head group dehydration are both associated with the L beta----Lc phase transition, the observation of the pressure effects on the rate of crystalline Lc phase formation is used to show that the head group dehydration plays a predominant role in controlling the kinetics of the L beta----Lc phase transition.

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“…Although some studies of deuterium nuclear spin relaxation in tissues have been reported, with some exceptions, most of these deal with muscle or brain and are at relatively low field strengths compared to those which are now available for chemical-shift imaging studies (4- 1 1). In more recent work, the deuterium relaxation times of deuterium oxide interacting with Escherichia coli membrane lipids have also been reported (22). It is the purpose of this communication to present new deuterium relaxation measurements for a variety of tissues at 13.7 MHz (2.1 T) and to point out a relationship to proton relaxation times which appears to exist at a similar frequency.…”

Section: Introductionmentioning

confidence: 92%

Deuterium nuclear spin relaxation in biological tissues

Block

Parekh

1987

Magnetic Resonance in Med

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The deuterium nuclear spin relaxation times have been measured in tissues taken from rats given 20% deuterium oxide in their drinking water. The spin-lattice and spin-spin relaxation times were measured at 13.7 MHz by the inversion-recovery and Carr-Purcell-Meiboom-Gill FT methods, respectively. The reciprocals of the spin-lattice (T1) relaxation times were found to correlate well with those of protons in similar nondeuteriated tissues at a similar frequency (13.6 MHz) measured in a separate study. A least-squares analysis of the data yields (1/T1)H = (0.991)(1/T1)D - 3.48 for five tissues (standard deviations of 0.097 for the slope and 0.383 for the intercept with a correlation coefficient of 0.986). Implications with respect to relaxation mechanisms are discussed.

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Hydration of Escherichia coli lipids

Cited by 62 publications

References 13 publications

Dynamics of lipid domain formation: Fluctuation analysis

Dynamics of lipid domain formation: Fluctuation analysis

Pressure effect on the rate of crystalline phase formation of L-alpha-dipalmitoylphosphatidylcholines in multilamellar dispersions

Deuterium nuclear spin relaxation in biological tissues

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