Influence of subcutaneous injection of essential fatty acids on the stress-induced modifications of rat platelet aggregation and membrane lipid composition

We investigated the influence of four different culture media: 20% fetal bovine serum (FBS), 5% FBS, 5% FBS supplemented with 10 mg·L-1 linoleic acid (18:2(n-6)) or alpha-linolenic acid (18:3(n-3)) on alpha-linolenic acid apical uptake in clone TC7 of human intestinal Caco-2 cell line. Neither cellular viability nor cell monolayer integrity and permeability were altered by the four culture conditions. Our results show that the different culture media led to changes in alpha-linolenic acid maximal rate of uptake (Vmax) but did not alter the apparent transport constant (Km). Reducing FBS concentration from 20% to 5% increased significantly the rate of alpha-linolenic acid uptake, which was further increased by supplementation of the medium with 18:2(n-6) or 18:3(n-3). Supplementation with essential fatty acids led to a marked enrichment of brush-border membrane phospholipids in polyunsaturated fatty acids of the corresponding series and decreased significantly the levels of monounsaturated fatty acids. Saturated fatty acids, unsaturation index, and cholesterol / fatty acid ratios were unchanged. No clear relation could be established between the changes in membrane lipid composition and the alterations of alpha-linolenic acid uptake. These results indicate a weak influence of membrane lipid composition in the modulation of the uptake. Therefore, the increase of uptake following long-term supplementation of TC7 cells with essential fatty acids could be attributed to an increase of the expression of membrane protein(s) involved in the apical uptake of long-chain fatty acids. This remains to be established.Key words: fatty acid intestinal absorption, Caco-2 cells, membrane fatty acid transport protein, membrane phospholipid fatty acid composition.

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Effects of temperature on the structure and metabolism of cell membranes in fish

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1984.246.4.r460 ◽

1984 ◽

Vol 246 (4) ◽

pp. R460-R470 ◽

Cited By ~ 27

Author(s):

J. R. Hazel

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Cold Exposure ◽

Lipid Composition ◽

Membrane Lipid ◽

Effect Of Temperature ◽

Salmo Gairdneri ◽

Homeoviscous Adaptation ◽

Cold Temperatures ◽

Membrane Lipid Composition

The metabolic adjustments responsible for the “homeoviscous adaptation” of membrane lipid composition in fish are examined with special reference to the rainbow trout, Salmo gairdneri. The percentage of fatty acid lipogenesis attributable to unsaturates was elevated after an acute drop in temperature but declined with continued cold exposure (i.e., cold acclimation). In contrast, selected desaturation reactions [particularly those involved in the production of polyunsaturated fatty acids (PUFA) of the n-3 and/or n-6 families] proceeded more rapidly in cold-than in warm-acclimated trout. Different time courses for the change in monoene and PUFA levels of hepatic microsomal membranes during thermal acclimation suggest that the various desaturase enzymes contribute to the acclimatory response at different times. Certain fatty acids, particularly the delta 5-desaturation products of the n-3 (20:5 delta 5,8,11,14,17) and n-6 (20:4 delta 5,8,11,14) series, were preferentially incorporated into phospholipids at cold temperatures and by cold-acclimated trout, due in part to the direct effect of temperature on the substrate preferences of the phospho- and acyltransferase enzymes of de novo phospholipid biosynthesis; however, chain length rather than degree of unsaturation per se may determine the temperature-dependent pattern of fatty acid incorporation. Both acute and chronic cold exposure elevated the incorporation of PUFA into phosphatidylserine (PS), suggesting that the conversion of PS to phosphatidylethanolamine (PE) may be activated at cold temperatures. The rate of homeoviscous adaptation appears to be limited by the rate of membrane lipid turnover, which although generally positively correlated with acclimation temperature, did vary depending on the phospholipid moiety and tissue considered. Finally the direct acylation of lysophospholipids formed during the process of membrane turnover may contribute to both rapid and acclimatory adjustments in membrane lipid composition.

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Effects of Long Term Polyunsaturated Fatty Acids Supplementation on Membrane Lipid Composition and Growth Characteristics in Rats

Journal of Animal and Veterinary Advances ◽

10.3923/javaa.2011.2575.2581 ◽

2011 ◽

Vol 10 (19) ◽

pp. 2575-2581 ◽

Cited By ~ 1

Author(s):

A.L. Tan ◽

M. Ebrahimi ◽

T. Hajjar ◽

S. Vidyadaran ◽

A.Q. Sazili ◽

...

Keyword(s):

Fatty Acids ◽

Polyunsaturated Fatty Acids ◽

Lipid Composition ◽

Membrane Lipid ◽

Growth Characteristics ◽

Membrane Lipid Composition

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Effect of elevated temperature on membrane lipid saturation in Antarctic notothenioid fish

PeerJ ◽

10.7717/peerj.4765 ◽

2018 ◽

Vol 6 ◽

pp. e4765 ◽

Cited By ~ 8

Author(s):

Vanita C. Malekar ◽

James D. Morton ◽

Richard N. Hider ◽

Robert H. Cruickshank ◽

Simon Hodge ◽

...

Keyword(s):

Fatty Acids ◽

New Zealand ◽

Lipid Composition ◽

Unsaturated Fatty Acids ◽

Antarctic Fish ◽

Membrane Lipid ◽

Thermal Acclimation ◽

Homeoviscous Adaptation ◽

Antarctic Species ◽

Membrane Lipid Composition

Homeoviscous adaptation (HVA) is a key cellular response by which fish protect their membranes against thermal stress. We investigated evolutionary HVA (long time scale) in Antarctic and non-Antarctic fish. Membrane lipid composition was determined for four Perciformes fish: two closely related Antarctic notothenioid species (Trematomus bernacchiiandPagothenia borchgrevinki); a diversified related notothenioid Antarctic icefish (Chionodraco hamatus); and a New Zealand species (Notolabrus celidotus). The membrane lipid compositions were consistent across the three Antarctic species and these were significantly different from that of the New Zealand species. Furthermore, acclimatory HVA (short time periods with seasonal changes) was investigated to determine whether stenothermal Antarctic fish, which evolved in the cold, stable environment of the Southern Ocean, have lost the acclimatory capacity to modulate their membrane saturation states, making them vulnerable to anthropogenic global warming. We compared liver membrane lipid composition in two closely related Antarctic fish species acclimated at 0 °C (control temperature), 4 °C for a period of 14 days inT. bernacchiiand 28 days forP. borchgrevinki,and 6 °C for 7 days in both species. Thermal acclimation at 4 °C did not result in changed membrane saturation states in either Antarctic species. Despite this, membrane functions were not compromised, as indicated by declining serum osmolality, implying positive compensation by enhanced hypo-osmoregulation. Increasing the temperature to 6 °C did not change the membrane lipids ofP. borchgrevinki.However, inT. bernacchii,thermal acclimation at 6 °C resulted in an increase of membrane saturated fatty acids and a decline in unsaturated fatty acids. This is the first study to show a homeoviscous response to higher temperatures in an Antarctic fish, although for only one of the two species examined.

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Impaired fetal erythrocytes' filterability: relationship with cell size, membrane fluidity, and membrane lipid composition

Blood ◽

10.1182/blood.v79.8.2148.2148 ◽

1992 ◽

Vol 79 (8) ◽

pp. 2148-2153 ◽

Cited By ~ 7

Author(s):

FC Colin ◽

Y Gallois ◽

D Rapin ◽

A Meskar ◽

JJ Chabaud ◽

...

Keyword(s):

Fatty Acids ◽

Membrane Fluidity ◽

Lipid Composition ◽

Fluorescence Polarization ◽

High Performance ◽

Unsaturated Fatty Acids ◽

Membrane Lipid ◽

Gas Liquid Chromatography ◽

Biophysical Parameters ◽

Membrane Lipid Composition

Abstract The lipid composition of erythrocytes (red blood cells [RBCs]) plays a significant role in determining certain membrane biophysical properties. We have found that fetal RBCs showed a dramatically low filterability compared with adult RBCs and questioned whether this could be a consequence of their membrane lipid composition. We therefore studied fetal RBCs at two different gestational ages, neonatal RBCs and adult RBCs. Biophysical parameters were studied using two different techniques, filterability and membrane fluidity. The latter was measured by fluorescence polarization using three different probes. The membrane lipid composition was examined by measuring cholesterol and phospholipids. After extraction of the phospholipids, followed by high performance thin-layer chromatography, the fatty acids in the phospholipid subfractions were analyzed by gas-liquid chromatography. The fetal RBCs' filterability was found to be correlated with both the larger size and the higher hemoglobin content of the cells, but there was no correlation between RBC filterability and fluidity or membrane lipid composition. In adult RBCs, compared with neonatal RBCs, the slight increase of unsaturated fatty acids in phosphatidylcholine and phosphatidylethanolamine should have increased the membrane fluidity. However, in RBCs, no change was observed in the fluidity parameters measured by fluorescence polarization.

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Med15B Regulates Acid Stress Response and Tolerance in Candida glabrata by Altering Membrane Lipid Composition

Applied and Environmental Microbiology ◽

10.1128/aem.01128-17 ◽

2017 ◽

Vol 83 (18) ◽

Cited By ~ 18

Author(s):

Yanli Qi ◽

Hui Liu ◽

Jiayin Yu ◽

Xiulai Chen ◽

Liming Liu

Keyword(s):

Fatty Acids ◽

Atpase Activity ◽

Lipid Composition ◽

Candida Glabrata ◽

Membrane Integrity ◽

Acid Stress ◽

Membrane Lipid ◽

Low Ph ◽

Content Type ◽

Membrane Lipid Composition

ABSTRACT Candida glabrata is a promising producer of organic acids. To elucidate the physiological function of the Mediator tail subunit Med15B in the response to low-pH stress, we constructed a deletion strain, C. glabrata med15BΔ, and an overexpression strain, C. glabrata HTUΔ/CgMED15B. Deletion of MED15B caused biomass production, glucose consumption rate, and cell viability to decrease by 28.3%, 31.7%, and 26.5%, respectively, compared with those of the parent (HTUΔ) strain at pH 2.0. Expression of lipid metabolism-related genes was significantly downregulated in the med15BΔ strain, whereas key genes of ergosterol biosynthesis showed abnormal upregulation. This caused the proportion of C18:1 fatty acids, the ratio of unsaturated to saturated fatty acids (UFA/SFA), and the total phospholipid content to decrease by 11.6%, 27.4%, and 37.6%, respectively. Cells failed to synthesize fecosterol and ergosterol, leading to the accumulation and a 60.3-fold increase in the concentration of zymosterol. Additionally, cells showed reductions of 69.2%, 11.6%, and 21.8% in membrane integrity, fluidity, and H+-ATPase activity, respectively. In contrast, overexpression of Med15B increased the C18:1 levels, total phospholipids, ergosterol content, and UFA/SFA by 18.6%, 143.5%, 94.5%, and 18.7%, respectively. Membrane integrity, fluidity, and H+-ATPase activity also increased by 30.2%, 6.9%, and 51.8%, respectively. Furthermore, in the absence of pH buffering, dry weight of cells and pyruvate concentrations were 29.3% and 61.2% higher, respectively, than those of the parent strain. These results indicated that in C. glabrata, Med15B regulates tolerance toward low pH via transcriptional regulation of acid stress response genes and alteration in lipid composition. IMPORTANCE This study explored the role of the Mediator tail subunit Med15B in the metabolism of Candida glabrata under acidic conditions. Overexpression of MED15B enhanced yeast tolerance to low pH and improved biomass production, cell viability, and pyruvate yield. Membrane lipid composition data indicated that Med15B might play a critical role in membrane integrity, fluidity, and H+-ATPase activity homeostasis at low pH. Thus, controlling membrane composition may serve to increase C. glabrata productivity at low pH.

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