scholarly journals A correlation between membrane fluidity and the critical temperature for cell adhesion.

1976 ◽  
Vol 71 (2) ◽  
pp. 670-674 ◽  
Author(s):  
M J Ueda ◽  
T Ito ◽  
T S Okada ◽  
S I Ohnishi
Keyword(s):  
Cell Adhesion ◽  
Critical Temperature ◽  
Stearic Acid ◽  
Membrane Fluidity ◽  
Characteristic Temperatures ◽  
Esr Spectrum ◽  
Plastic Dish

BHK 21 cells can adhere to a protein-coated plastic dish in the presence of Ca2+ at temperatures above 12 degrees C. However, they cannot adhere below 8 degrees C. The ESR spectrum of cells spin-labeled with a stearic acid label indicated that the membrane fluidity changed characteristically at 10 degrees C, 20 degrees C, and 30 degrees C. The critical temperature for cell adhesion coincided well with one of the characteristic temperatures for the membrane fluidity change. In the case of adhesion in the presence of Mg2+, no such correlation was observed.

A POSSIBLE CORRELATION BETWEEN SUPPRESSION OF SUPERCONDUCTIVITY, MAGNETIC ORDERING AND NORMAL STATE RESISTIVITY PARAMETERS IN THE Yb1-xPrxBa2Cu3O7-δ SYSTEM

2002 ◽  
Vol 16 (08) ◽  
pp. 261-273 ◽  
Author(s):  
ANURAG GUPTA ◽  
H. NARAYAN ◽  
P. N. LISBOA-FILHO ◽  
C. A. CARDOSO ◽  
FERNANDO M. ARAUJO MOREIRA ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Normal State ◽  
Magnetic Ordering ◽  
Residual Resistivity ◽  
Gradual Decrease ◽  
Normal State Resistivity ◽  
Characteristic Temperatures ◽  
Antiferromagnetic Ordering ◽  
Diamagnetic Transition ◽  
The Difference

Polycrystalline samples of the Pr doped Yb 1-x Pr x Ba 2 Cu 3 O 7-δ (i.e. Yb(Pr)-123) system for 0≤x≤1 have been investigated for resistivity ρ and magnetization M as a function of temperature in normal and superconducting states. The gradual decrease in superconducting critical temperature T c (x) is found to be correlated with the x-dependent ratio of resistivity slope (dρ/dT) cc (corresponding to the linear ρ(T) region) and residual resistivity ρ0. In particular, the observed difference of critical Pr concentration where superconductivity is destroyed (x c ) in Yb(Pr)-123 (x c ≈ 0.65) and Y(Pr)-123 (x c ≈ 0.55) matches with the difference in the value of Pr concentration where the ratio (dρ/dT) cc /ρ0 tends to go to zero in them. The M(T) data of the Yb(Pr)-123 samples show magnetic ordering for x > x c at characteristic temperatures, Tn, that increase with x. Interestingly, the Yb(Pr)-123 sample with Pr content (x = 0.6) near x c reveals several anomalous features like transition from metallic to semiconducting-like ρ(T), an excessive broadening of the diamagnetic transition and weakening of the M(T) signal related to antiferromagnetic ordering of Pr ions. These observations can be consistently interpreted by assuming the presence of dynamically fluctuating striped phase in these systems.

scholarly journals Vitex Agnus-Castus L. Essential Oil Increases Human Erythrocyte Membrane Fluidity

2012 ◽  
Vol 31 (3) ◽  
pp. 222-227 ◽  
Author(s):  
Vladimir Ajdžanović ◽  
Ivan Spasojević ◽  
Jasmina Pantelić ◽  
Branka Šošić-Jurjević ◽  
Branko Filipović ◽  
...  
Keyword(s):  
Essential Oil ◽  
Stearic Acid ◽  
Membrane Fluidity ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Human Erythrocyte Membrane ◽  
Hydrophobic Membrane ◽  
Increased Risk ◽  
Agnus Castus ◽  
Erythrocyte Membrane Fluidity

Vitex Agnus-CastusL. Essential Oil Increases Human Erythrocyte Membrane FluidityErythrocyte membrane fluidity is related to their rheologic behavior, the dynamic quality of erythrocytes, which is tempted in hypertension and atherosclerosis. An increased risk of these and other cardiovascular diseases occurs in ageing women. Menopause-related conditions are often treated with hormone replacement therapy that may increase the risk of malignancies.Vitex agnus-castusL. essential oil contains various organic compounds (monoterpenes, sesquiterpenes and terpenoids), and is increasingly used as an alternative therapy for menopausal symptoms. These components of the oil may be incorporated into cell membranes, thereby changing the membrane fluidity. The aim of this study was to determine the effects ofVitex agnus-castusessential oil on human erythrocyte membrane fluidity at graded depths. We used Electron Paramagnetic Resonance spectroscopy and fatty acid spin probes (5-doxyl stearic acid and 12-doxyl stearic acid), whose spectra depend on membrane fluidity. After treatment withVitex agnus-castusessential oil the erythrocytes had a significant (p=0.029) and reversible increase in membrane fluidity in the deeper hydrophobic membrane regions, with no change (p>0.05) in fluidity near the membrane's hydrophilic surface. These results document increased fluidity of the human erythrocyte membrane byVitex agnus-castusessential oil, and this action may be useful in patients with menopause-related hypertension and other cardiovascular conditions.

scholarly journals Electron Spin Resonance Spectroscopy of Serum Albumin: A Novel New Test for Cancer Diagnosis and Monitoring

2006 ◽  
Vol 52 (11) ◽  
pp. 2129-2134 ◽  
Author(s):  
Steven C Kazmierczak ◽  
Andrey Gurachevsky ◽  
Gert Matthes ◽  
Vladimir Muravsky
Keyword(s):  
Electron Spin Resonance ◽  
Stearic Acid ◽  
Serum Albumin ◽  
Cancer Patients ◽  
Electron Spin ◽  
Spin Probe ◽  
Esr Spectroscopy ◽  
Resonance Spectroscopy ◽  
Esr Spectrum ◽  
Spin Resonance

Abstract Background: Proteins released by tumor cells can bind to serum albumin, leading to structural and functional modifications. We used electron spin resonance (ESR) spectroscopy to measure these changes in serum albumin and evaluate their utility for the diagnosis and monitoring of cancer. Methods: We used an ESR spectrometer and 16-doxyl stearic acid as spin probe to measure conformational changes in albumin in blood samples from a population of healthy donors and volunteers (n = 349), patients with a wide variety of hematologic and nonhematologic malignancy (n = 135), and patients with chronic diseases such as gastrointestinal and pulmonary disease, diabetes, and cirrhosis (n = 91). We added differing amounts of 16-doxyl stearic acid spin probe in ethanol to 50 μL of serum from each patient to create 3 different aliquots that differed in concentration of spin probe and ethanol, then incubated the aliquots for 10 min at 37 °C with continuous shaking. We measured the ESR spectra of each aliquot in triplicate and used proprietary software (MedInnovation GmbH) to evaluate the ESR spectrum for differences between cancer patients and the other groups. Results: The diagnostic sensitivity and specificity of this test were 87.4% and 95.7%, respectively, for differentiating healthy individuals from cancer patients and 87.4%, and 85.7% for differentiating cancer patients from chronic disease patients. Serial evaluation of albumin conformation changes in several patients followed during the course of their disease showed excellent agreement between the magnitude of abnormality in the ESR spectrum of albumin and clinical and pathologic estimates of disease severity. Conclusions: ESR spectroscopy of serum albumin is a sensitive and noninvasive technique that clearly demonstrates diagnostic utility in patients with cancer. This test also enables monitoring of the disease course through use of serial measurements.

scholarly journals Electron Spin Resonance Evaluation of Buccal Membrane Fluidity Alterations by Sodium Caprylate and L-Menthol

2021 ◽  
Vol 22 (19) ◽  
pp. 10708
Author(s):  
Laxmi Shanthi Chede ◽  
Brett A. Wagner ◽  
Garry R. Buettner ◽  
Maureen D. Donovan
Keyword(s):  
Electron Spin Resonance ◽  
Stearic Acid ◽  
Membrane Fluidity ◽  
Electron Spin ◽  
Spin Labels ◽  
Permeation Enhancers ◽  
Head Groups ◽  
Spin Resonance ◽  
Sodium Caprylate ◽  
Membrane Fluidization

The ability of sodium caprylate and l-menthol to fluidize phospholipid bilayers composed of lipids simulating the buccal epithelium was investigated using electron spin resonance (ESR) to evaluate the action of these agents as permeation enhancers. 5-Doxyl stearic acid (5-DSA) and 16-doxyl stearic acid (16-DSA) were used as spin labels to identify alterations in membrane fluidity near the polar head groups or inner acyl regions of the lipid bilayer, respectively. The molecular motion of both 5-DSA and 16-DSA showed increased disorder near the polar and inner hydrophobic regions of the bilayer in the presence of sodium caprylate suggesting fluidization in both the regions, which contributes to its permeation enhancing effects. L-menthol decreased the order parameter for 16-DSA, showing membrane fluidization only in the inner acyl regions of the bilayer, which also corresponded to its weaker permeation enhancing effects. The rapid evaluation of changes in fluidity of the bilayer in the presence of potential permeation enhancers using ESR enables improved selection of effective permeation enhancers and enhancer combinations based on their effect on membrane fluidization.

scholarly journals Organization of membrane lipids and proteins in human En(a-) erythrocytes that lack the major sialoglycoprotein, glycophorin A. A spin-label study

1981 ◽  
Vol 195 (1) ◽  
pp. 123-128 ◽  
Author(s):  
S E Jansson ◽  
J Gripenberg ◽  
R Hekali ◽  
C G Gahmberg
Keyword(s):  
Stearic Acid ◽  
Membrane Fluidity ◽  
Membrane Lipids ◽  
Spin Labels ◽  
Glycophorin A ◽  
Hydrophobic Core ◽  
Protein Motion ◽  
Normal Cells ◽  
Label Study ◽  
Spin Resonance

Membrane fluidity was studied by electron-spin-resonance techniques in human En(a-) erythrocytes that lack the major membrane sialoglycoprotein, glycophorin A. By using stearic acid spin labels with a doxyl group in the C-12 or C-15 positions, we demonstrated that the hydrophobic core in these cells was more fluid than in normal cells. Surface-located regions in isolated En(a-) membranes, when probed with stearic acid labelled in the C-5 position, appeared more stable than in normal membranes. In isolated En(a-) membranes, protein motion was decreased when probed with a nitroxide derivative of maleimide. After incubation with anti-(glycophorin A) antibodies protein motion and membrane fluidity were increased in normal membranes. This effect was observed also after spectrin depletion, which by itself increased protein motion but decreased membrane fluidity in the hydrophobic core of the membrane. The results show that membrane proteins influence the fluidity of membrane lipids.

Sign in / Sign up

Export Citation Format

Share Document