The role of cholesterol in lipid membranes

The role of cholesterol in bilayer and monolayer lipid membranes has been of great interest. On the biophysical front, cholesterol significantly increases the order of the lipid packing, lowers the membrane permeability, and maintains membrane fluidity by forming liquid-ordered–phase lipid rafts. However, direct observation of any influence on membrane chemistry related to these cholesterol-induced physical properties has been absent. Here we report that the addition of 30 mol % cholesterol to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (POPG) monolayers at the air–water interface greatly reduces the oxidation and ester linkage cleavage chemistries initiated by potent chemicals such as OH radicals and HCl vapor, respectively. These results shed light on the indispensable chemoprotective function of cholesterol in lipid membranes. Another significant finding is that OH oxidation of unsaturated lipids generates Criegee intermediate, which is an important radical involved in many atmospheric processes.

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Evaluating the Role of Oxidative Stress in Acute Ischemic Stroke

Journal of Neurosciences in Rural Practice ◽

10.1055/s-0039-3402675 ◽

2020 ◽

Vol 11 (01) ◽

pp. 156-159

Author(s):

Bindu Menon ◽

Krishnan Ramalingam ◽

Rajeev Kumar

Keyword(s):

Oxidative Stress ◽

Ischemic Stroke ◽

Acute Stroke ◽

Acute Ischemic Stroke ◽

Lipid Membranes ◽

Demographic Data ◽

Stroke Severity ◽

Stroke Patients ◽

Antioxidant Power

Abstract Background The role of oxidative stress in neuronal injury due to ischemic stroke has been an interesting topic in stroke research. Malondialdehyde (MDA) has emerged as a sensitive oxidative stress biomarker owing to its ability to react with the lipid membranes. Total antioxidant power (TAP) is another biomarker to estimate the total oxidative stress in stroke patients. We aimed to determine the oxidative stress in acute stroke patients by measuring MDA and TAP. Materials and Methods MDA and TAP were determined in 100 patients with ischemic stroke and compared with that in 100 age- and sex-matched healthy adults. Demographic data, stroke severity measured by the National Institutes of Health Stroke Scale (NIHSS), and disability measured by the Barthel index (BI) were recorded. The association of MDA and TAP with other variables was analyzed by paired t-test. Results Of the whole sample, 74% represented males. The mean NIHSS score was 13.11 and BI was 38.87. MDA was significantly higher in stroke patients (7.11 ± 1.67) than in controls (1.64 ± 0.82; p = 0.00). TAP was significantly lower in stroke patients (5.72 ± 1.41) than in controls (8.53 ± 2.4; p = 0.00). The lipid profile and blood sugar levels were also significantly higher in stroke patients. There was no association of MDA and TAP with other variables. Conclusion We found that oxidative stress was associated with acute ischemic stroke. However, we could not establish an association between oxidative stress and the severity of acute stroke.

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Oxidation of Polyunsaturated Lipid Membranes by Photocatalytic Titanium Dioxide Nanoparticles: Role of pH and Salinity

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c08642 ◽

2020 ◽

Vol 12 (29) ◽

pp. 32446-32460 ◽

Cited By ~ 1

Author(s):

Elisa Parra-Ortiz ◽

Sara Malekkhaiat Häffner ◽

Thomas Saerbeck ◽

Maximilian W. A. Skoda ◽

Kathryn L. Browning ◽

...

Keyword(s):

Titanium Dioxide ◽

Lipid Membranes ◽

Titanium Dioxide Nanoparticles

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Thermal fluctuations of giant vesicles and elastic properties of bilayer lipid membranes. The role of the excess surface

Progress in Colloid & Polymer Science - Trends in Colloid and Interface Science III ◽

10.1007/bfb0116179 ◽

2007 ◽

pp. 11-17 ◽

Cited By ~ 4

Author(s):

J. F. Faucon ◽

. Méléard ◽

M. D. Mitov ◽

I. Bivas ◽

P. Bothorel

Keyword(s):

Elastic Properties ◽

Lipid Membranes ◽

Thermal Fluctuations ◽

Bilayer Lipid Membranes ◽

Giant Vesicles ◽

Bilayer Lipid ◽

Excess Surface

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Fluid deformable surfaces

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.549 ◽

2019 ◽

Vol 878 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

A. Voigt

Keyword(s):

Lipid Membranes ◽

Shape Change ◽

Governing Equations ◽

Tight Coupling ◽

Tangential Flow ◽

Deformable Surfaces ◽

Bending Elasticity ◽

Natural Element ◽

Numerical Tools

Lipid membranes are examples of fluid deformable surfaces, which can be viewed as two-dimensional viscous fluids with bending elasticity. With this solid–fluid duality any shape change contributes to tangential flow and vice versa any tangential flow on a curved surface induces shape deformations. This tight coupling between shape and flow makes curvature a natural element of the governing equations. The modelling and numerical tools outlined in Torres-Sánchez et al. (J. Fluid Mech., vol. 872, 2019, pp. 218–271) open a new field of study by enabling the exploration of the role of curvature in this context.

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