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PubMed1991

Correlation between low-temperature immunosuppression and the absence of unsaturated fatty acid synthesis in murine T cells.

1. Studies were performed to determine if the inability of murine T cells to provide primary helper function at low temperature (27 degrees C) could be correlated with their inability to synthesize unsaturated fatty acids (UFAs). 2. In the absence of exogenous oleic acid (18:1), splenocytes responded to a T-dependent (TD) Ag (trinitrophenyl-keyhole limpet hemocyanin, TNP-KLH) at 37 degrees C but not at 27 degrees C. The addition of 150 microM 18:1 almost completely restored plaque-forming cell (PFC) responses to TNP-KLH at 27 degrees C but markedly suppressed PFC responses to the TD Ag at 37 degrees C. 3. During incubation at 27 degrees C, B cells converted 3- to 5-fold more stearic acid (18:0) to 18:1 and showed a greater accumulation of monounsaturated phospholipid molecular species than did T cells. 4. Following incubation in the presence of a rescuing dose of 18:1 (150 microM), both B and T cells accumulated large amounts of dioleoyl PC. 5. It is proposed that the absence of 18:1 synthesis in T cells is responsible for the unique low temperature susceptibility of this lymphocyte population.

Animals↗

PubMed1995

Alteration of plasma lipids in the rat by fractionation of modified milk fat (butterfat).

Our objective was to determine the nutritional effects of defined fat fractions of modified milk fat, or butterfat (anhydrous butter without the milk fat globule membrane) on lipid and lipoprotein cholesterol concentrations in plasma of rats fed diets containing 16% fat and two amounts of cholesterol. Five dietary fats were compared: 1) intact butterfat, 2) a liquid butterfat fraction enriched in oleic acid and unsaturated triacylglycerols with < 40 carbon atoms, 3) a solid butterfat fraction enriched in palmitic and stearic acids, 4) corn oil, and 5) palm oil. The extent of diet-induced hypercholesterolemia was the greatest with palm oil, followed by solid butterfat, corn oil, intact butterfat, and the lowest with liquid butterfat. Triacylglycerol concentrations in plasma were greater for rats fed palm oil than for those fed corn oil or liquid or intact butterfat. Among the high cholesterol dietary groups, ingestion of the liquid butterfat diet resulted in similar lipoprotein cholesterol and very low density lipoprotein concentrations relative to the corn oil diet, and ingestion of the solid butterfat diet resulted in similar lipoprotein cholesterol and very low density lipoprotein concentrations relative to the palm oil diet. These results suggest that changes in the triacylglycerol and fatty acid composition of butterfat by fractionation processes may improve its nutritional profile.

Animals↗

PubMed1996

Characterization and identification of an adrenal age-related nonpolar fluorescent substance.

The adrenal cortexes of humans and rodents accumulate lipofuscin with age, but the chemical nature of the substance that produces lipofuscin fluorescence in the gland is not known. Analysis of rat adrenal nonpolar lipids revealed a fluorescence profile with increased intensity in the lipids extracted from older animals (23-24 months > 6 months > 6 weeks). The peak occurred at a wavelength of 470 +/- 5 nm(n = 26) when excited at 340 nm. After sucrose density gradient centrifugation, the fluorescent substance was primarily concentrated in subcellular lipid droplets rather than supernatant or particulate. Prolonged stimulation of rats with ACTH for 7 consecutive days caused 14-51% decreases in the fluorescence levels, with a tendency of return to control levels poststimulation regardless of age. In contrast, the nonpolar lipids of mouse adrenal tumor (Y1) cells, which contain no lipofuscin, did not display this fluorescence in the presence or absence of ACTH. The chromatographic characteristics of the substance in a silica gel-60 column resembled those of authentic retinyl palmitate and cholesteryl oleate. Analysis of the substance by HPLC demonstrated at least three prominent peaks, designated XI-3 in order. X1 and X2 were minor peaks; X3 was the major peak. Whereas none of the peaks comigrated with cholesteryl esters, X1 comigrated with authentic retinyl palmitate. Determination of the fatty acid component of the major fluorescent substance X3 by gas-liquid chromatography disclosed stearic acid. Retinyl stearate was, therefore, synthesized. The fluorescent profiles, HPLC retention time and mass spectrometric fragmentation of purified X3 substance were all identical to those of the synthetic compound. In contrast, the rat liver principally accumulated retinyl palmitate with age. Thus, we conclude that 1) the major nonpolar fluorescent substance accumulated in the rat adrenal with age is retinyl stearate, which may be a fluorophore of adrenal lipofuscin; 2) ACTH action may be related to this accumulation; and 3) the type of retinyl ester accumulated in aged animals is organ specific.

Adrenal Cortex↗

PubMed1972

Characterization and in vivo production of three glycolipids from Candida Bogoriensis: 13-glucopyranosylglucopyranosyloxydocosanoic acid and its mono- and diacetylated derivatives.

Three glycosides of 13-hydroxydocosanoic acid isolated from Candida bogoriensis were characterized by quantitating the amount of carbohydrate, acetate, and hydroxy acid in each, and by gas-liquid chromatography and mass spectrometry of their methyl ester, trimethylsilyl ether derivatives. One of the glycosides was the diacetylated derivative of 13-glucosylglucosyloxydocosanoic acid previously characterized by Tulloch, Spencer, and Deinema (Can. J. Chem., 46: 345 [1968]), in which the disaccharide had the beta(1 --> 2) sophorose linkage and the acetyl groups were attached to the 6' and 6" positions of the glucose residues. The other two glycosides were 13-glucosylglucosyloxydocosanoic acid and its monoacetylated derivative. A comparison of the mass spectra of derivatives indicates that the acetyl group of the monoacetyl lipid is on the internal glucose. Methyl 13-glucosyloxydocosanoate was produced by acid hydrolysis of the methyl ester of the unacetylated glycolipid and was characterized by the same techniques as the other glycolipids. Time course of production of the three glycolipids is consistent with the diacetylated derivative being the first extra-cellular product and the other two glycolipids being formed by deacetylation. 13-Hydroxy[13-(3)H]docosanoic acid, methyl 13-hydroxy[13-(3)H]docosanoate, and 9-hydroxy[11,12-(3)H]-stearic acid were each incorporated into the glycolipid fraction.

Candida↗

PubMed1981

Emission wavelength-dependent decay of the 9-anthroyloxy-fatty acid membrane probes.

Using the phase-modulation technique, we have measured the fluorescence decay of 2- and 12-(9-anthroyloxy)-stearic acid (2- and 12-AS) and 16-(9-anthroyloxy)-palmitic acid (16-AP) bound to egg phosphatidylcholine vesicles or dissolved in nonpolar solvents. Heterogeneity analysis demonstrates that the decay is generally not monoexponential and exhibits large component variations across it emission spectrum. The mean decay time increases (and in parallel, the steady-state polarization decreases) monotonically with increasing wavelength from values at the blue end. The decay at the red side of the emission spectrum contains an exponential term with a negative amplitude, indicating that emission occurs from intermediates created in the excited-state. This behavior is interpreted as arising from intramolecular fluorophore relaxation occurring on the time scale of the fluorescence lifetime. We believe this to be the first study of wavelength-dependent fluorescent emission which is dominated by an intramolecular relaxation process. Although the three probes exhibit qualitatively similar effects, the emission band variations are greatest for 2-AS and smallest for 16-AP. The differences among the probes are not entirely due to environmental factors as demonstrated, for example, by the emission polarization differences observed in the isotropic solvent paraffin oil. In summary, while these findings point out some of the complexities in the 9-anthroyloxy-fatty acids as membrane probes, they also indicate how these complexities might be used as a sensitive measure of lipid-probe interaction.

Anthracenes↗

PubMed1989

Radiolabeled 9- or 10-monoiodostearic acid and 9- or 10-monoiodostearyl carnitine--I. Synthesis and purification.

The purpose of this investigation was to synthesize and purify radiolabeled 9- or 10-monoiodostearyl carnitine for potential use as a perfusion and metabolic imaging agent for the heart. Oleic acid was iodinated via a free radical addition reaction of HI across the double bond to give 9- or 10-monoiodostearic acid which in turn was esterified with carnitine. The identity of 9- or 10-monoiodostearic acid and 9- or 10-monoiodostearyl carnitine was determined using nuclear magnetic resonance (NMR), infrared (i.r.), ultraviolet (u.v.), and mass spectroscopy. The purity of the fatty acid and carnitine ester was established by thin layer chromatography. 9- or 10-Monoiodo[125I]stearic acid and 9- or 10-monoiodo[125I]stearyl carnitine were synthesized via the isotopic exchange of 125I for cold iodine bonded to 9- or 10-monoiodostearic acid and 9- or 10-monoiodostearyl carnitine.

Carnitine↗

PubMed1989

Manipulation of plasma membrane physical state affects desaturase activity in rat lymphocytes.

Thymocytes, obtained from young rats, were incubated in the presence of either diheptadecanoylphosphatidylcholine or dioleylphosphatidylcholine vesicles and desaturation of either [1-14C]stearic acid or [1-14C]linoleic acid was followed in the endoplasmic reticulum. Incubation with diheptadecanoylphosphatidylcholine resulted in an accumulation of heptadecanoic acid in the plasma membrane, but not in the endoplasmic reticulum and mitochondria, and an increase in membrane ordering as assessed by diphenylhexatriene fluorescence polarization. A shift to higher temperature of the phase separation in the plasma membrane was also observed. Both delta 9 and delta 6 desaturase activities were enhanced in these cells, with delta 6 responding more intensly. Accumulation of oleic acid in the plasma membrane could not be observed when the cells were incubated in the presence of dioleylphosphatidylcholine vesicles, but all the membranes separated, including the microsomes, became more fluid. This can be attributed to removal of cholesterol by the vesicles. Fluidization of plasma membrane and endoplasmic reticulum depressed the conversion of stearate to oleate and linoleate to gamma-linolenate. It is concluded that there is an exchange of information between the plasma membrane and the endoplasmic reticulum in order to maintain the proper fluidity relationships and that this occurs without transfer of lipids from the former to the latter.

Animals↗

PubMed1995

Changes of adenylate cyclase activity in AH-130 ascites hepatoma of Yoshida induced by enrichment with fatty acids.

Enrichment of hepatoma cells with arachidonic acid increases fluidity of plasma membranes, unstimulated lipid peroxidation and basal adenylate cyclase activity, whereas enrichment with stearic acid decreases fluidity and does not cause any variation in lipid peroxidation or adenylate cyclase. The increase in adenylate cyclase activity may be due to the increase not only in fluidity, but also in lipid peroxidation products. Indeed, adenylate cyclase is stimulated by 4-hydroxynonenal, one important product of lipid peroxidation, when added to plasma membranes. 4-hydroxynonenal increases adenylate cyclase two-fold in unenriched plasma membranes and three-fold in plasma membranes enriched with arachidonic acid in comparison with basal activity.

Adenylyl Cyclases↗

PubMed1980

The fluidity of plasma membranes of Dictyostelium discoideum. The effects of polyunsaturated fatty acid incorporation assessed by fluorescence depolarization and electron paramagnetic resonance.

Two probe techniques, fluorescence depolarization (using diphenylhexatriene) and electron paramagnetic resonance (using 5-doxyl stearic acid), have been used to assess the fluidity of the purified plasma membranes of Dictyostelium discoideum. Both techniques indicate that a large incorporation of polyunsaturated fatty acids into the plasma membranes does not significantly change membrane fluidity In addition, phosphatidylcholines isolated from cells grown on both polyunsaturated fatty acid-supplemented and unsupplemented media exhibit similar mobilities of an incorporated spin probe when dispersed in aqueous solution. This result suggests that the enrichment of a membrane already high in content of fatty acyl chains containing two double bonds with those containing three or more double bonds does not markedly change fluidity.

Cell Membrane↗

PubMed1989

Induction of an endothermic transition in the Arrhenius plot of fatty acid uptake by lipid-depleted ascites tumor cells.

Cultured ascites tumor cells and their lipid-depleted variants containing 35-40% less membrane phospholipid and cholesterol were used to study uptake and metabolism of fatty acids complexed to albumin. Uptake of stearate and oleate at 37 degrees C was considerably higher in the lipid-depleted cells, but no significant difference in the affinity constants for stearate uptake of 3.70 microM for the lipid-depleted and 2.50 microM for the control cells was observed. Similar rates of uptake of both cultures were observed at lower temperatures up to 30 degrees C. The drastic increase in stearate uptake above 30 degrees C resulted in an endothermic transition in the Arrhenius plot with an activation energy of 20.8 kJ/mol versus 6.5 kJ/mol for the control cells. Uptake of stearate and oleate of the control cells was only slightly reduced by metabolic inhibitors, which was similar to stearic acid transport in the lipid-depleted variants. However, oleate uptake was substantially decreased in these variants. Incorporated stearate was esterified to about 50% in both cultures, and oleate between 85 and 90%. Mainly triacylglycerols and phospholipids with phosphatidylcholine (41%) and phosphatidylethanolamine (35%) as major polar lipid components, and also lower acylglycerols and cholesterol were found to be labeled. Under lipid-depleted conditions, a pronounced increase in the relative proportion of oleate incorporation into triacylglycerols was determined. It is suggested that fatty acid uptake is controlled by the number of active sites of the putative transport protein, which increases upon lipid depletion as shown from the V values. This increase may result from the segregation of membrane-bound proteins into domains (Haeffner et al. (1986) Cell Mol. Biol. 32, 359-368), which are known to be formed as a consequence of lipid phase separation in the lipid-depleted cells.

Animals↗

PubMed1988

Fluorescence high performance liquid chromatographic analysis of free fatty acid levels changed during aggregation of rat platelets.

Stimuli-induced changes in free fatty acid levels of activated platelets were assayed by reversed-phase high performance liquid chromatography. The fatty acids were prelabeled as their fluorescent 9-aminophenanthrene derivatives for the detection. The levels of saturated fatty acids such as palmitic acid in an extracellular medium of rat platelet-rich plasma are significantly raised by stimulation with 10 microM ADP or 8 micrograms/ml collagen. Similar increases in saturated fatty acids liberated from washed rat platelets are also observed by using thrombin stimulation. Quantitative changes in the intra- and extracellular levels of fatty acids induced by washed platelet aggregation were assayed after addition of thrombin for 15 min. Increase in palmitic and stearic acid was observed approximately 3-fold their levels of that the unstimulated control.

Adenosine Diphosphate↗

PubMed1991

Physiological significance of fatty acid elongation system in adrenoleukodystrophy.

We studied the metabolism of radioactive fatty acids in cultured skin fibroblasts from patients with adrenoleukodystrophy (ALD) and Zellweger syndrome (ZS) to clarify the physiological significance of the fatty acid elongation system in the accumulation of very long chain fatty acids (VLFA) in ALD. A substantial amount of radioactive C26:0 was synthesized from [18-14C]stearic acid by ALD and ZS fibroblasts, whereas radioactive C26:0 was not detected in control fibroblasts. Kinetic studies demonstrated that the production of radioactive C24:0 and C26:0 in ALD fibroblasts is higher than that of ZS fibroblasts, which suggests that the fatty acid elongation activity plays an important role for the accumulation of VLFA in ALD, in addition to the decreased VLFA oxidation activities. The addition of monounsaturated fatty acids including oleic acid and erucic acid specifically lowered the formation rate of VLFA without any significant effect on degradation activities of VLFA both in ALD and control fibroblasts. The results suggest that the mechanism of decrease of VLFA by administration of monounsaturated fatty acids is based on the inhibition of fatty acid elongation activity.

Adrenoleukodystrophy↗

PubMed1986

Effect of exogenous lipids incorporated into the membrane of human erythrocytes on its glucose transport activity.

Addition of a phosphatidylcholine (dilinoleoyl), lysophosphatidylcholine (palmitoyl), saturated or unsaturated long-chain fatty acid (stearic or oleic) into human erythrocyte suspension caused both dose-dependent incorporation of the lipid into the membrane and inhibition of the glucose transport across the membrane. Loading to or partial removal of cholesterol from the membrane increased or decreased the transport rate, respectively. There was no correlation between the changes in the transport activity and those in cell shape caused by such alterations in the membrane lipid composition.

Blood Glucose↗

PubMed2001

Changes in fatty acids composition during seed growth and physicochemical characteristics of oil extracted from four safflower cultivars.

Fatty acid contents at different stages of maturity and physicochemical characteristics of oil extracted from mature seeds of four safflower cultivars (S208, S400, S541, and S303) were studied. Results indicated that for all cultivars both saturated and unsaturated fatty acid contents fluctuated with seed growth and development. Palmitic acid content decreased up to day 20 after which it started to increase for the S400, S541, and S303 cultivars, while for S208 it progressively decreased. Stearic acid fluctuated with seed growth and development. Oleic acid showed slight changes with seed growth and development, while linoleic acid decreased with seed growth and development for the S400, S541, and S303 cultivars while for S208 after day 30, it started to increase significantly. For all cultivars, glyceride contents varied among the cultivars with maximum values of 97.70, 2.80 and 0.20 for tri-, di- and monoglycerides, respectively. Physicochemical investigation of mature seed oils showed that the color, density, refractive index, free fatty acids, peroxide value, saponification value and unsaponifiable matter were similar for all cultivars while viscosity, iodine value, and acetone insoluble matter varied among the cultivars.

Chemical Phenomena↗

PubMed1993

Performance of dairy cows fed short staple, Pima, and cracked Pima cottonseed and feed characteristics.

Compared with short staple cottonseed, Pima cottonseed was higher in CP, ether extract, and oleic acid and lower in NDF, ADF, and linoleic acid. Pima cottonseed had greater bulk density, but short staple cottonseed had stronger seed coat strength; Pima cottonseed contained more of the (-)-gossypol isomer than short staple cottonseed. Lactating Holstein cows were fed whole short staple cottonseed, whole Pima cottonseed, and cracked Pima cottonseed at 15% of dietary DM for 70 d after a pretrial covariate period. The DMI was not significantly different among treatments, but cows fed whole Pima tended to yield less milk than those fed short staple and less FCM than those fed cracked Pima. Feed efficiency was improved by processing Pima cottonseed. Milk fat content was higher for whole and cracked Pima than for short staple cottonseed; gross feed efficiency was greatest for cows fed cracked Pima cottonseed. Whole cottonseed in feces was highest for whole Pima, intermediate for short staple, and negligible for cracked Pima cottonseed. Concentrations of milk stearic acid were lower, and linoleic acid higher, for cows fed cracked Pima than for cows fed short staple cottonseed. Total tract digestibility of ADF was least on the cracked Pima cottonseed diet, and ether extract digestibility was higher on cracked than on whole Pima cottonseed diets.

Animal Feed↗

PubMed2005

PPAR-gamma response element activity in intact primary human adipocytes: effects of fatty acids.

OBJECTIVE: We studied the activity and regulation of the peroxisome proliferator-activated receptor-gamma response element (PPRE) in primary human adipocytes. METHODS: We transfected primary human adipocytes with a plasmid-encoding firefly luciferase cDNA under control of a PPRE from the acyl-coenzyme A oxidase gene by using our newly developed electroporation-based method. Several fatty acids were added to the fat cells to study potential activation of peroxisome proliferator-activated receptor-gamma. RESULTS: Cells responded maximally to 5 microM of rosiglitazone at a 5.1 +/- 1.4-fold over basal increase in luciferase activity. There was a positive correlation between body mass index and the response to 5 microM of rosiglitazone (r = 0.36, P = 0.03). Patients with type 2 diabetes had similar basal PPRE activity but responded more strongly to 5 microM of rosiglitazone than did non-diabetic subjects (10.2 +/- 5-fold and 5.4 +/- 1-fold over basal increase, respectively, P < 0.0001). Among saturated fatty acids, lauric acid was without effect, but 10 microM of palmitic or stearic acid increased PPRE activity 20% to 35% above basal levels. Monounsaturated palmitoleic acid at 1 microM induced a PPRE transcriptional activity that corresponded to half the therapeutic levels of rosiglitazone. CONCLUSION: Adipocytes from obese subjects and patients with type 2 diabetes responded particularly strongly to the effect of rosiglitazone on PPRE. Because fatty acids in the diet can affect the transcriptional activity of peroxisome proliferator-activated receptor-gamma over decades, the stimulation induced by stearic and palmitoleic acids can affect insulin sensitivity and, hence, cardiovascular morbidity and mortality in humans.

Adipocytes↗

PubMed1989

[Composition and immunological activity of membrane-bound surface glycoprotein from Crithidia oncopelti].

A membrane-bound glycoprotein with a molecular weight of 10000-12000 was isolated from Crithidia oncopelti and purified. The glycoprotein contained peptide, carbohydrate and lipid fragments and phosphorus. The peptide fragment was represented by 10 amino acids. The carbohydrate fragment was represented by 7 monosaccharides. The lipid part was mainly represented by stearic acid. The glycoprotein showed immunostimulating properties. It had a comitogenic effect on murine spleen cells in vitro and induced tumoricidal activity in murine peritoneal macrophages in vitro and in vivo.

Adjuvants, Immunologic↗

PubMed1994

Synthesis and aggregative properties of GM1 ganglioside (IV3Neu5AcGgOse4Cer) containing D-(+)-2-hydroxystearic acid.

GM1 ganglioside containing a hydroxylated fatty acid moiety, GM1(OH), was synthesized starting from lyso-GM1 and D-(+)-2-hydroxystearic acid. The aggregative, geometrical and distribution properties of GM1(OH) were compared with those of stearic acid containing GM1 ganglioside; laser light scattering measurements, differential scanning calorimetry and fluorescence spectroscopy were used. GM1 and GM1(OH) are present in solution as micelles with a hydrodynamic radius of 58.7 and 60.0 A, and molecular mass of 470 and 570 kDa, respectively. The surface area occupied by the monomer of GM1(OH) at the lipid-water interface of the aggregate was calculated to be 117 A2, which is 3 A2 lower than that determined for GM1. Proton NMR analyses of GM1 and GM1(OH) suggest different three-dimensional structures at the ganglioside lipid-water interface. Both GM1(OH) and GM1 inserted into dipalmitoylphosphatidylcholine (DPPC) vesicles undergo segregation phenomena, with the formation of ganglioside-enriched microdomains, but GM1(OH) shows a higher degree of dispersion in the DPPC matrix and exerts a lower rigidifying effect than does GM1.

1,2-Dipalmitoylphosphatidylcholine↗