Search results for "unsaturated"
showing 10 items of 439 documents
Polyunsaturated fatty acids in cultured cardiomyocytes : effect on physiology and beta-adrenoceptor function
1992
This study was carried out to investigate the influence of the membrane fatty acid composition on the basal electrical and contractile activities and the response to beta-adrenergic stimulation of rat cardiac muscle cells in culture. Cells were grown for 3 days in a conventional serum culture medium and then incubated for 24 h in synthetic media containing either n-6 or n-3 as the sole source of polyunsaturated fatty acids (PUFA). The n-6/n-3 ratio in the phospholipids was 0.9 in the n-3 cells and 13.1 in the n-6 cells compared with 6.3 in controls cells. Such modifications did not alter action potentials and the main parameters related to contraction, although shortening was slightly acce…
Environment- and sequence-dependent modulation of the double-stranded to single-stranded conformational transition of gramicidin A in membranes.
1998
The role of the membrane lipid composition and the individual Trp residues in the conformational rearrangement of gramicidin A along the folding pathway to its channel conformation has been examined in phospholipid bilayers by means of previously described size-exclusion high-performance liquid chromatography HPLC-based strategy (Bano et al. (1991) Biochemistry 30, 886). It has been demonstrated that the chemical composition of the membrane influences the transition rate of the peptide rearrangement from double-stranded dimers to beta-helical monomers. The chemical modification of Trp residues, or its substitution by the more hydrophobic residues phenylalanine or naphthylalanine, stabilized…
Changes in fatty acid compositions of total serum and lipoprotein particles, in growing rats given protein-deficient diets with either hydrogenated c…
1994
The present study examines the effects of dietary saturated (hydrogenated coconut oil) and polyunsaturated (salmon oil) fats on the composition and metabolism of lipoproteins in growing rats fed on protein-deficient diets. Four groups of rats were fed on the following diets for 28 d: 200 g casein+50 g coconut oil (COC)/kg, 20 g casein+50 g coconut oil (COd)/kg, 200 g casein + 50 g salmon oil (SAC)/kg, 20 g casein+50 g salmon oil (SAd)/kg. Both protein-deficient groups exhibited low concentrations of protein and triacylglycerol (in serum, very-low-density lipoprotein (VLDL), low-density lipoprotein-high-density lipoprotein, (LDL-HDL1) and HDL2-3), of cholesterol (in LDL-HDL1) and of phosphol…
Liver X receptor activation promotes polyunsaturated fatty acid synthesis in macrophages : relevance in the context of atherosclerosis
2015
Objective— Liver X receptors (LXRs) modulate cholesterol and fatty acid homeostasis as well as inflammation. This study aims to decipher the role of LXRs in the regulation of polyunsaturated fatty acid (PUFA) synthesis in macrophages in the context of atherosclerosis. Approach and Results— Transcriptomic analysis in human monocytes and macrophages was used to identify putative LXR target genes among enzymes involved in PUFA biosynthesis. In parallel, the consequences of LXR activation or LXR invalidation on PUFA synthesis and distribution were determined. Finally, we investigated the impact of LXR activation on PUFA metabolism in vivo in apolipoprotein E–deficient mice. mRNA levels of acyl…
Effects of Strength Training and Nutritional Counseling on Metabolic Health Indicators in Aging Women
2005
Purpose: Effects of strength training (ST) and nutritional counseling (NC) on metabolic health indicators were examined in 50 aging women. Methods: Subjects performed ST for 21 weeks. NC was given to obtain sufficient energy and protein intake, and recommended intake of fat and fiber. Results: NC increased intake of protein and polyunsaturated fat by 4.5% and 10.7% and decreased intake of saturated fat by 18.3%. Serum concentrations of total cholesterol (TC), LDL-cholesterol (LDL-C), total and HDL-cholesterol (HDL-C) ratio and triacylglycerols (TAG) decreased, and serum HDL-C increased in all subjects after ST. Respectively, systolic and diastolic blood pressure and serum insulin concentrat…
The role of diet in multiple sclerosis
2022
Multiple sclerosis (MS) is a disease of the central nervous system (CNS), characterized by chronic inflammation associated with autoimmune damage to myelin and axons leading to neurodegeneration. Although the etiology is not fully understood, some factors that increase the risk of disease have been identified. One of the key elements of multidisciplinary approach to the management of MS is a properly balanced diet, e.g. Swank diet. Its main assumption is to reduce the supply of animal fats in favor of fats of plant origin, which contain polyunsaturated fatty acids omega-3. One of the factors influencing the course of the disease is vitamin D deficiency. In 80-90% it is synthesized by exposu…
Inferring phytoplankton community composition with a fatty acid mixing model
2015
The taxon specificity of fatty acid composition in algal classes suggests that fatty acids could be used as chemotaxonomic markers for phytoplankton composition. The applicability of phospholipid-derived fatty acids as chemotaxonomic markers for phytoplankton composition was evaluated by using a Bayesian fatty acid-based mixing model. Fatty acid profiles from monocultures of chlorophytes, cyanobacteria, diatoms, euglenoids, dinoflagellates, raphidophyte, cryptophytes and chrysophytes were used as a reference library to infer phytoplankton community composition in five moderately humic, large boreal lakes in three different seasons (spring, summer and fall). The phytoplankton community compo…
Changes in membrane lipid composition in ethanol- and acid-adapted Oenococcus oeni cells: characterization of the cfa gene by heterologous complement…
2008
International audience; Cyclopropane fatty acid (CFA) synthesis was investigated in Oenococcus oeni. The data obtained demonstrated that acid-grown cells or cells harvested in the stationary growth phase showed changes in fatty acid composition similar to those of ethanol-grown cells. An increase of the CFA content and a decrease of the oleic acid content were observed. The biosynthesis of CFAs from unsaturated fatty acid phospholipids is catalysed by CFA synthases. Quantitative real-time-PCR experiments were performed on the cfa gene of O. oeni, which encodes a putative CFA synthase. The level of cfa transcripts increased when cells were harvested in stationary phase and when cells were gr…
Inhibition of fatty acid delta 6- and delta 5-desaturation by cyclopropene fatty acids in rat liver microsomes.
1993
delta 6-Desaturation of linoleic acid and delta 5-desaturation of dihomo-gamma-linolenic acid were measured in liver microsomes from rats fed fresh Baobab seed oil containing cyclopropene fatty acids (malvalic acid and sterculic acid) or heated Baobab seed oil practically devoid of these fatty acids or control oil. The presence of cyclopropene fatty acids in the fresh Baobab oil diet highly depressed both desaturations, but delta 6- more than delta 5-desaturation. The decreased capacity of microsomes to desaturate was reflected in the lower arachidonic acid content in microsomal phospholipids from rats fed this oil. However it was also lower in rats fed heated oil although in vitro delta 6-…
Cyclopropanation of Membrane Unsaturated Fatty Acids Is Not Essential to the Acid Stress Response of Lactococcus lactis subsp. cremoris
2011
ABSTRACT Cyclopropane fatty acids (CFAs) are synthetized in situ by the transfer of a methylene group from S -adenosyl- l -methionine to a double bond of unsaturated fatty acid chains of membrane phospholipids. This conversion, catalyzed by the Cfa synthase enzyme, occurs in many bacteria and is recognized to play a key role in the adaptation of bacteria in response to a drastic perturbation of the environment. The role of CFAs in the acid tolerance response was investigated in the lactic acid bacterium Lactococcus lactis MG1363. A mutant of the cfa gene was constructed by allelic exchange. The cfa gene encoding the Cfa synthase was cloned and introduced into the mutant to obtain the comple…