Membrane lipids and sodium pumps of cattle and crocodiles: an experimental test of the membrane pacemaker theory of metabolism

2004 ◽  
Vol 287 (3) ◽  
pp. R633-R641 ◽  
Author(s):  
B. J. Wu ◽  
A. J. Hulbert ◽  
L. H. Storlien ◽  
P. L. Else
Keyword(s):  
Fatty Acids ◽  
Lipid Composition ◽  
Sodium Pump ◽  
Bos Taurus ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Sodium Pumps ◽  
Lipid Source ◽  
Microsomal Membranes ◽  
Membrane Pacemaker

The influence of membrane lipid composition on the molecular activity of a major membrane protein (the sodium pump) was examined as a test of the membrane pacemaker theory of metabolism. Microsomal membranes from the kidneys of cattle (Bos taurus) and crocodiles (Crocodylus porosus) were found to possess similar sodium pump concentrations, but cattle membranes showed a four- to fivefold higher enzyme (Na+-K+-ATPase) activity when measured at 37°C. The molecular activity of the sodium pumps (ATP/min) from both species was fully recoverable when delipidated pumps were reconstituted with membrane from the original source (same species). The results of experiments involving species membrane crossovers showed cattle sodium pump molecular activity to progressively decrease from 3,245 to 1,953 ( P < 0.005) to 1,031 ( P < 0.003) ATP/min when subjected to two cycles of delipidation and reconstitution with crocodile membrane as a lipid source. In contrast, the molecular activity of crocodile sodium pumps progressively increased from 729 to 908 ( P < 0.01) to 1,476 ( P = 0.01) ATP/min when subjected to two cycles of delipidation and reconstitution with cattle membrane as a lipid source. The lipid composition of the two membrane preparations showed similar levels of saturated (∼31–34%) and monounsaturated (∼23–25%) fatty acids. Cattle membrane had fourfold more n-3 polyunsaturated fatty acids (11.2 vs. 2.9%) but had a reduced n-6 polyunsaturate content (29 vs. 43%). The results support the membrane pacemaker theory of metabolism and suggest membrane lipids and their polyunsaturates play a significant role in determining the molecular activity of the sodium pump.

scholarly journals Effect of membrane environment on the activity and inhibitability by malonyl-CoA of the carnitine acyltransferase of hepatic microsomal membranes

1997 ◽  
Vol 322 (2) ◽  
pp. 435-440 ◽  
Author(s):  
Neil M. BROADWAY ◽  
E. David SAGGERSON
Keyword(s):  
Lipid Composition ◽  
Membrane Lipids ◽  
Specific Activity ◽  
Membrane Lipid ◽  
Microsomal Membrane ◽  
Membrane Lipid Composition ◽  
Carnitine Acyltransferase ◽  
Malonyl Coa ◽  
Microsomal Membranes ◽  
Myristoyl Coa

We have investigated the extent to which membrane environment affects the catalytic properties of the malonyl-CoA-sensitive carnitine acyltransferase of liver microsomal membranes. Arrhenius-type plots of activity were linear in the absence and presence of malonyl-CoA (2.5 μM). Sensitivity to malonyl-CoA increased with decreasing assay temperature. Partly purified enzyme displayed an increased K0.5 (substrate concentration supporting half the maximal reaction rate) for myristoyl-CoA and a reduced sensitivity to malonyl-CoA compared with the enzyme in situ in membranes. Reconstitution with liposomes of a range of compositions restored the K0.5 for myristoyl-CoA to values similar to that seen in native membranes. The lipid requirements for restoration of sensitivity to malonyl-CoA were more stringent. When animals were starved for 24 h the specific activity of carnitine acyltransferase in microsomal membrane residues was increased 3.3-fold, whereas sensitivity to malonyl-CoA was decreased to 1/2.8. When enzymes partly purified from fed and starved animals were reconstituted into crude soybean phosphatidylcholine liposomes there was no difference in sensitivity to malonyl-CoA. When partly purified enzyme from fed rats was reconstituted into liposomes prepared from microsomal membrane lipids from fed animals it was 2.2-fold more sensitive to malonyl-CoA than when reconstituted with liposomes prepared from microsomal membrane lipids from starved animals. This suggests that the physiological changes in sensitivity to malonyl-CoA are mediated via changes in membrane lipid composition rather than via modification of the enzyme protein itself. The increased specific actvity of acyltransferase observed on starvation could not be attributed to changes in membrane lipid composition.

Membrane Lipids and Maximum Lifespan in Clownfish

2021 ◽  
Author(s):  
PEDRO FRANCISCO ALMAIDA PAGÁN ◽  
Alejandro Lucas-Sanchez ◽  
Antonio Martinez-Nicolas ◽  
Eva Terzibasi ◽  
Maria Angeles Rol de Lama ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Potential Model ◽  
Membrane Lipids ◽  
Membrane Lipid ◽  
Maximum Lifespan ◽  
Homeoviscous Adaptation ◽  
Theory Of Aging ◽  
Peroxidation Index ◽  
Membrane Peroxidation ◽  
Contradictory Data

Abstract The longevity-homeoviscous adaptation (LHA) theory of aging states that lipid composition of cell membranes is linked to metabolic rate and lifespan, which has been widely shown in mammals and birds but not sufficiently in fish. In this study, two species of the genus Amphiprion (A. percula and A. clarkii, with estimated maximum lifespan potentials [MLSP] of 30 and 9-16 years, respectively) and the damselfish Chromis viridis (estimated MLSP of 1-2 years) were chosen to test the LHA theory of aging in a potential model of exceptional longevity. Brain, livers and samples of skeletal muscle were collected for lipid analyses and integral part in the computation of membrane peroxidation indexes (PIn) from phospholipid (PL) fractions and PL fatty acid composition. When only the two anemonefish were compared, results pointed to the existence of a negative correlation between membrane PIn value and maximum life expectancy, well in line with the predictions from the LHA theory of aging. Nevertheless, contradictory data were obtained when the two clownfish were compared to the shorter-lived C. viridis. This results along with those obtained in previous studies on fish denote that the magnitude (and sometimes the direction) of the differences observed in membrane lipid composition and peroxidation index with MLSP cannot explain alone the diversity in longevity found among fishes.

scholarly journals Lipid composition of the isolated rat intestinal microvillus membrane

1968 ◽  
Vol 109 (1) ◽  
pp. 51-59 ◽  
Author(s):  
G. G. Forstner ◽  
K. Tanaka ◽  
K. J. Isselbacher
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Neutral Lipid ◽  
Lipid Composition ◽  
Plasma Membranes ◽  
Membrane Lipids ◽  
Saturated Fatty Acids ◽  
Polar Lipids ◽  
Published Data ◽  
Microvillus Membrane

1. Rat intestinal microvillus plasma membranes were prepared from previously isolated brush borders and the lipid composition was analysed. 2. The molar ratio of cholesterol to phospholipid was greatest in the membranes and closely resembled that reported for myelin. 3. Unesterified cholesterol was the major neutral lipid. However, 30% of the neutral lipid fraction was accounted for by glycerides and fatty acid. 4. Five phospholipid components were identified and measured, including phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, sphingomyelin and lysophosphatidylcholine. Though phosphatidylethanolamine was the chief phospholipid, no plasmalogen was detected. 5. In contrast with other plasma membranes in the rat, the polar lipids of the microvillus membrane were rich in glycolipid. The cholesterol:polar lipid (phospholipid+glycolipid) ratio was about 1:3 for the microvillus membrane. Published data suggest that this ratio resembles that of the liver plasma membrane more closely than myelin or the erythrocyte membrane. 6. The fatty acid composition of membrane lipids was altered markedly by a single feeding of safflower oil. Membrane polar lipids did not contain significantly more saturated fatty acids than cellular polar lipids. Differences in the proportion of some fatty acids in membrane and cellular glycerides were noted. These differences may reflect the presence of specific membrane glycerides.

scholarly journals Revealing Further Insights on Chilling Injury of Postharvest Bananas by Untargeted Lipidomics

Foods ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 894 ◽  
Author(s):  
Juan Liu ◽  
Qingxin Li ◽  
Junjia Chen ◽  
Yueming Jiang
Keyword(s):  
Fatty Acids ◽  
Low Temperature ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Saturated Fatty Acids ◽  
Chilling Injury ◽  
Membrane Damage ◽  
Membrane Lipid ◽  
Banana Fruit ◽  
Control Fruit

Chilling injury is especially prominent in postharvest bananas stored at low temperature below 13 °C. To elucidate better the relationship between cell membrane lipids and chilling injury, an untargeted lipidomics approach using ultra-performance liquid chromatography–mass spectrometry was conducted. Banana fruit were stored at 6 °C for 0 (control) and 4 days and then sampled for lipid analysis. After 4 days of storage, banana peel exhibited a marked chilling injury symptom. Furthermore, 45 lipid compounds, including glycerophospholipids, saccharolipids, and glycerolipids, were identified with significant changes in peel tissues of bananas stored for 4 days compared with the control fruit. In addition, higher ratio of digalactosyldiacylglycerol (DGDG) to monogalactosyldiacylglycerol (MGDG) and higher levels of phosphatidic acid (PA) and saturated fatty acids but lower levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and unsaturated fatty acids were observed in banana fruit with chilling injury in contrast to the control fruit. Meanwhile, higher activities of phospholipase D (PLD) and lipoxygenase (LOX) were associated with significantly upregulated gene expressions of MaPLD1 and MaLOX2 and higher malondialdehyde (MDA) content in chilling injury-related bananas. In conclusion, our study indicated that membrane lipid degradation resulted from reduced PC and PE, but accumulated PA, while membrane lipid peroxidation resulted from the elevated saturation of fatty acids, resulting in membrane damage which subsequently accelerated the chilling injury occurrence of banana fruit during storage at low temperature.

Erythrocytes and Skeletal Muscle Unsaturated and Omega-6 Fatty Acids Are Positively Correlated after Caloric Restriction and Exercise

2018 ◽  
Vol 72 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Miquel Martorell ◽  
Victoria Pons ◽  
Joan Carles Domingo ◽  
Xavier Capó ◽  
Antoni Sureda ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Caloric Restriction ◽  
Lipid Composition ◽  
Nutritional Intervention ◽  
Membrane Lipid ◽  
Omega 3 ◽  
Post Exercise ◽  
Before And After ◽  
Omega 6

Background: Nutritional intervention studies with fatty acid (FA) supplements assess the efficacy of the intervention by measuring the changes in erythrocyte membrane lipid profiles reflected in tissue composition changes. The aim was to determine the effects of caloric restriction (CR) on erythrocytes lipid composition and to compare and correlate these changes with skeletal muscle acid profiles after CR. Methods: Erythrocytes were obtained from 11 healthy men before and after 4 weeks of 33% CR in post-exercise conditions; muscle biopsies were obtained from the same athletes after 4 weeks of 33% CR in post-exercise conditions. Samples were used for FA determination by chromatography. Results: CR significantly modified erythrocyte FAs composition. Skeletal muscle FA profile was significantly different from that for the erythrocytes. The erythrocyte FA profile was more saturated (52.1 ± 1.5% and 32.8 ± 0.9%, respectively) and less monounsaturated (21.0 ± 0.8% and 39.0 ± 2.0%, respectively) than the skeletal muscle FA profile and similarly polyunsaturated. Conclusions: CR modifies erythrocyte lipid composition, mainly omega-6 FAs. Erythrocyte monounsaturated, polyunsaturated and omega-6 FAs, but not the saturated and omega-3 FAs, were significantly positively correlated with skeletal muscle FAs. There is a discordance between saturated and omega-3 FAs from erythrocyte and from muscle, but monounsaturated, polyunsaturated and omega-6 fatty acids are positively correlated.

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