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PubMed1981

Long-chain fatty acid perturbations in Mycoplasma pneumoniae.

The fatty acid content of Mycoplasma pneumoniae increased 2.5- to 9.6-fold when the growth medium was supplemented with a saturated, unsaturated, or beta-hydroxy fatty acid, the greatest increase occurring with palmitic acid. The amount of each supplemented fatty acid found within this organism was 2.8 to 5.5% of the total fatty acid content; the exception was palmitic acid. Up to 57% of the palmitic acid was utilized from the supplemented medium, whereas only 0.2 to 10% of the other fatty acids was utilized. Chromatographic and isotopic analyses revealed that 22% of the labeled palmitic acid incorporated from the palmitic acid-supplemented medium remained free in this organism. Also, even though complex lipid synthesis increased a minimum of 3.8-fold under these conditions, this mycoplasma continued to incorporate intact complex lipids from the growth medium. Bacteriostatic and bactericidal studies which used high concentrations of various long-chain fatty acids showed that only palmitic, myristic, and beta-hydroxydecanoic acids were not bactericidal. The addition of palmitic acid to the growth medium resulted in the formation of exceedingly long, filamentous cells in approximately 25% of the population. Osmotic fragility and electron spin resonance spectroscopy studies showed a correlation among this increased fatty acid content, decreased membrane fluidity, and the increased osmotic fragility of palmitic acid-grown cells. In addition, these cells had a lowered cholesterol content. The effect of such compositional changes on osmotic fragility is discussed in this paper. Finally, the profound increase in the total fatty acid content of palmitic acid-grown cells altered neither sensitivity to tetracycline or erythromycin nor the amount of hydrogen peroxide secreted.

Fatty Acids↗
PubMed1992

Phospholipid composition and subcellular distribution in yeast and mycelial forms of Candida albicans.

Lipids were found to constitute 3.9% and 4.7% of the dry weight of yeast and mycelial forms of Candida albicans, respectively. Phospholipids were localized mainly in the microsomal fraction of both growth forms and phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and cardiolipin were the major phospholipids. Myristic acid and palmitic acid were the predominant fatty acids in the yeast form while the mycelial form contained palmitic, palmitoleic and oleic acid as major fatty acids. Yeast forms showed significantly higher specific activities of intracellular phospholipase A and lysophospholipase when compared with mycelial forms. No significant difference in the specific activity of extracellular phospholipase A was seen in either morphogenic form while the activity of extracellular lysophospholipase was higher in the yeast form. These results are discussed in the context of the virulence of this fungus.

Candida albicans↗
PubMed1996

Chromatographic resolution of partially perdeuterated diglucosyldiacylglycerols from Acholeplasma laidlawii.

Diglucosyldiacylglycerol from Acholeplasma laidlawii was isolated by adsorption chromatography and subsequently subjected to molecular species analysis by reversed-phase high-performance liquid chromatography. Twenty-three molecular species were resolved. The bacterium was grown in a medium supplemented with a mixture of oleic acid and perdeuterated palmitic acid, and incorporation of perdeuterated acyl moieties occurred in several molecular species. Short and odd-numbered acyl chains were found in combinations with palmitic acid, perdeuterated palmitic acid and oleic acid. Also, molecular species differing only by perdeuterated and protonated acyl chain content were resolved chromatographically. Separation between diglucosyldiacylglycerol and digalactosyldiacylglycerol isolated from a plant source was achieved with adsorption chromatography. The polarity of diglucosyldiacylglycerol as compared to digalactosyldiacylglycerol is discussed.

Acholeplasma laidlawii↗
PubMed1981

Lipid composition of lung and lung lavage fluid from map turtles (Malaclemys geographica) maintained at different environmental temperatures.

The phospholipids of lung and lung lavage fluid from map turtles (Malaclemys geographica) acclimated to 5, 14, 22 and 32 degrees C have been analyzed. The yield of surfactant (lavage) lipid P was higher at 32 than at 5 degrees C, but there was no significant change in lung lipid P. The relative proportions of phospholipids from the lung were PC greater than PE greater than SM greater than PS greater than PI, while those for the lavage were PC greater than PI greater than PE greater than SM congruent to PS. PC constituted 71-78% of the surfactant phospholipid over the temperature range. Small changes in the amounts of PC and PE of lung and in PC and PI of lavage were observed at different temperatures. The fatty acid compositions of the lipids from the two sources were different in many respects. The lavage lipids contained more saturated acids, especially palmitic acid, than did the lung lipids. The fatty acid compositions indicated the presence of disaturated PC in lung lavage and diunsaturated species of PC and PE in lung. The total saturated fatty acids of PC and PE in lung and of PC in surfactant increased at higher temperatures. In the surfactant PC this increase reflected principally a rise in palmitate and a drop in palmitoleate contents. The saturated PC obtained from lavage at each temperature contained more than 85% palmitic acid, indicating that the principal saturated PC was DPPC. These changes are consistent with the type of alterations in the lipid composition of membranes which occur during homeoviscous adaptation.

Adaptation, Physiological↗
PubMed1991

Effects of high erucic acid rapeseed oil on fatty acid oxidation in rat liver.

The effects of high erucic acid rapeseed oil (HER) on fatty acid oxidation in rat liver compared with low erucic acid rapeseed oil (LER) were studied. Weanling male SD rats were fed diets containing 20% HER or LER for 1 week or 4 weeks, or 5% HER diet for 4 weeks. The hepatic oxidation capacity of butyric acid or palmitic acid was determined by titrating the propanone produced by their oxidation. The results showed that feeding HER to rats led to an increase in the weight of liver and a decrease in the hepatic oxidation capacity of palmitic acid. Hepatic oxidation of butyric acid was not influenced by the intake of HER. The inhibitory action of HER on the oxidation of long-chain fatty acids probably resulted from the incorporation of erucic acid into mitochondrial membranes, interfering the fatty acyl-CoA transferring system on the membranes, but not from the beta-oxidation enzyme system in mitochondria being directly inhibited.

Animals↗
PubMed1988

Effect of salicylic acid on mitochondrial-peroxisomal fatty acid catabolism.

To understand the possible role of salicylic acid in the pathogenesis of Reye's syndrome, we examined its effect on the oxidative metabolism of fatty acids in the rat liver mitochondrial-peroxisomal fraction. Fatty acids of different chain lengths are oxidized in different organelles. Octanoic acid is oxidized in mitochondria, lignoceric acid in peroxisomes, and palmitic acid in both mitochondria and peroxisomes. Salicylic acid (up to 1 mM concentration) had no effect on the oxidation of [1-14C]lignoceric acid. However, at the same concentration it inhibited the oxidation of [1-14C]palmitic acid by 26% and [1-14C] octanoic acid by 42%. The apparent Ki for the oxidation of [1-14C] octanoic acid, [1-14C]palmitic acid and [1-14C]lignoceric acid were 0.27, 6.0, and 14.8 mM, respectively. This selective inhibition of mitochondrial oxidation of medium-chain (octanoic acid) and long-chain (palmitic acid) fatty acids by salicylic acid may potentiate the accumulation of fatty acids in plasma in Reye's syndrome patients.

Animals↗
PubMed1992

Interferon-gamma stimulates lipid metabolism in human monocytes.

In nonactivated human monocytes, radiolabeled oleic, arachidonic, and palmitic acids are primarily incorporated into neutral lipids and phosphatidylcholine. Each of these fatty acids is also incorporated into phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and sphingomyelin in characteristic proportions which do not differ between donors. The phospholipid head group precursors, choline and serine, are incorporated into phosphatidylcholine, and phosphatidylserine and serine is incorporated into phosphatidylethanolamine and sphingomyelin. The incorporation of these lipid precursors and the total lipid content of monocytes activated with interferon-gamma were compared to those of nonactivated monocytes. Fatty acid incorporation into interferon-gamma-activated monocytes was dramatically increased, particularly for palmitic acid. Palmitic acid incorporation into phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and sphingomyelin was increased in activated cells by 167-387% at 2 hr and 215-274% at 4 hr compared to that of controls. The greatest increase in incorporation was for palmitic acid into sphingomyelin. Incorporation of arachidonic acid into phosphatidylinositol and serine into phosphatidylethanolamine was also increased in the interferon-gamma-activated monocytes. The total lipid content of activated and nonactivated monocytes did not differ. These results suggest that IFN-gamma activation induces a short-term stimulation of phospholipid metabolism which does not alter the gross lipid composition. Such modifications of phospholipid metabolism may be important in signal transduction as well as an indication of functional changes in the membranes of activated macrophages.

Fatty Acids↗
PubMed1994

Effects of free fatty acids found increased in women who develop pre-eclampsia on the ability of endothelial cells to produce prostacyclin, cGMP and inhibit platelet aggregation.

Recently, we showed that levels of circulating free fatty acids are increased in women who later develop pre-eclampsia long before the clinical onset of the disease. Among the serum free fatty acids, oleic-, linoleic-, and palmitic acid were found to be increased by 37, 25 and 25%, respectively. In the present study we asked if these free fatty acids can interfere with endothelial cell functions. Cultured endothelial cells were exposed to linoleic-, oleic- and palmitic acid in concentrations ranging from 0.016 to 0.133 mumol ml-1, resulting in molar ratios of free fatty acids to albumin of 0.2-1.6. We found that among these fatty acids, linoleic acid reduced the thrombin-stimulated prostacyclin release by 30-60%, oleic acid by 10-30%, whereas palmitic acid had no effect. Endothelial cells incubated in presence of linoleic acid showed a concentration-dependent reduction in prostacyclin release in response to thrombin, and cells incubated with linoleic acid for up to 28 h, showed a reduced thrombin-induced prostacyclin release at every time point. Endothelial level of cGMP mainly reflected the synthesis of endothelium-derived relaxing factor/nitrogen monoxide (EDRF/NO), since blocking of the endogenous production of EDRF/NO with N-omega-nitro-L-arginine, resulted in about 90% reduction in cGMP-content of the endothelial cells. Incubation with linoleic acid reduced the endothelial cGMP level by 70%. Linoleic acid reduced the endothelial cells ability to inhibit platelet aggregation by 10-45%, (p = 0.0019). It was concluded that linoleic acid impedes the ability of the endothelial cells to produce prostacyclin and cGMP, and to inhibit platelet aggregation.

Cells, Cultured↗
PubMed2005

Palm oil versus hydrogenated soybean oil: effects on serum lipids and plasma haemostatic variables.

The purpose of this study was to test if replacement of trans fatty acids by palmitic acid in an experimental margarine results in unfavourable effects on serum lipids and haemostatic factors. We have compared the effects of three different margarines, one based on palm oil (PALM-margarine), one based on partially hydrogenated soybean oil (TRANS- margarine) and one with a high content of polyunsaturated fatty acids (PUFA-margarine), on serum lipids in 27 young women. In nine of the participants fasting levels and diurnal postprandial levels of haemostatic variables on the 3 diets were compared. The sum of 12:0, 14:0, 16:0 provided 11% of energy (E%) in the PALM diet, the same as the sum of 12:0, 14:0, 16:0 and trans fatty acids in the TRANS-diet. Oleic acid provided 10-11E% in all three diets, while PUFA provided 5.7, 5.5 and 10.2 E%, respectively. Total fat provided 30-31% and the test margarines 26% of total energy in all three diets. Each of the diets was consumed for 17 days in a crossover design. There were no significant differences in total cholesterol, LDL-cholesterol and apoB between the TRANS- and the PALM-diet. HDL-cholesterol and apoA-I were significantly higher on the PALM-diet compared to the TRANS-diet while the ratio of LDL- to HDL-cholesterol was lower, although not significantly (P = 0.077) on the PALM-diet. Total cholesterol, LDL-cholesterol and apoB were significantly lower on the PUFA-diet compared to the two other diets. HDL-cholesterol was not different on the PALM- and the PUFA-diet while it was significantly lower on the TRANS-diet compared to the PUFA-diet. Triglycerides and Lp(a) were not different among the three diets. The diurnal postprandial state level of tissue plasminogen activator (t-PA) activity was significantly decreased on the TRANS-diet compared to the PALM-diet. t-PA activity was also decreased on the PUFA-diet compared to PALM-diet although not significantly (P=0.07). There were no significant differences in neither fasting levels or in circadian variation of t-PA antigen, PAI-1 activity, PAI-1 antigen, factor VII coagulant activity or fibrinogen between the three diets. Our results suggest that dietary palm oil may have a more favourable effect on the fibrinolytic system compared to partially hydrogenated soybean oil. We conclude that from a nutritional point of view, palmitic acid from palm oil may be a reasonable alternative to trans fatty acids from partially hydrogenated soybean oil in margarine if the aim is to avoid trans fatty acids. A palm oil based margarine is, however, less favourable than one based on a more polyunsaturated vegetable oil.

Adult↗
PubMed1986

Effect of fatty acids on aflatoxin production by Aspergillus parasiticus.

The effect of saturated and unsaturated fatty acids on aflatoxin production was studied in a synthetic medium. The aflatoxin production decreased (10-75%) in the presence of lauric acid and palmitic acid but the addition of behenic and sebacic acid stimulated aflatoxin production by 125-541%. Linolenic and linoleic acids effected aflatoxin production and mycelium growth. An 34-fold increase in aflatoxin production was observed with 50 mM linoleic acid. An inverse relationship was observed between aflatoxin production and mycelium mass, irrespective of the nature of the fatty acid.

Aflatoxins↗
PubMed1998

The use of FT-IR for quantitative studies of the apparent pKa of lipid carboxyl groups and the dehydration degree of the phosphate group of phospholipids.

Fourier-transform infrared spectroscopy (FT-IR) has been applied to the quantitative study of the dehydration of the phosphatidylserine phosphate group in the presence of Ca2+ exerted by different molecules, such as diacylglycerol, sphingosine and stearylarnine, by using a partial least-squares statistical procedure. By using this method it was observed that diacylglycerol enhanced the dehydration of this PO2- group produced by Ca2+ whereas the amino-bases sphingosine and stearylamine protected the phosphate group from the dehydration produced by Ca2+ due to the very strong electrostatic interaction established. The apparent pKa of lipid carboxyl groups can also be estimated by using FTIR. The method consisted in quantifying the absorbance intensities due to the protonated and the unprotonated forms of the specific group being studied. The pKa of the carboxyl group of [1-13C]-palmitic acid included in dipalmitoylphosphatidylcholine membranes was found to be 8.7, a value much higher than that estimated from a molecular solution of the fatty acid. It was observed using the same method that the pKa of free fatty acids in model stratum corneum lipid mixtures was in the range 6.2-7.3 increasing with the preponderance of oleic acid over palmitic acid. Finally the pKa of the carboxyl group of phosphatidylserine was shifted from 4.6 in the pure phospholipid to 2.1 and 2.2 in the presence of equimolar sphingosine and stearylamine, respectively, as a consequence of electrostatic interactions.

Calcium↗
PubMed1998

Preparation of slightly hydrophobic heparin derivatives which can be used for solvent casting in polymeric formulation.

Heparin is clinically administered mainly by intravenous injection because of its highly hydrophilic property. A slightly hydrophobic heparin derivative which can be dissolved in organic solvent can be widely used in polymeric devices for clinical applications. In this study, hydrophobic heparin derivatives were prepared by coupling heparin with deoxycholic acid, cholesterol, lauric acid, and palmitic acid, respectively. The hydrophobicity of these heparin derivatives depended on the feed mole ratio of heparin to hydrophobic agents, and they showed good solubility in the co-solvent of acetone and water, as well as in water alone. Also, these heparin derivatives showed high anticoagulant activity. This approach for preparing hydrophobic heparin is expected to advance the drug delivery system by further extending the applications of heparin to medical devices such as cardiopulmonary bypass circuits, heart lung oxygenators, and kidney dialyzers.

Cholesterol↗
PubMed2002

Troglitazone ameliorates lipotoxicity in the beta cell line INS-1 expressing PPAR gamma.

To elucidate the mechanisms by which troglitazone, which is a direct ligand for peroxisome proliferator-activated receptor (PPAR) gamma, ameliorates insulin resistance, we have demonstrated that PPAR gamma is expressed in a pancreatic beta cell line, INS-1, using reverse transcription-polymerase chain reaction (RT-PCR). We incubated the cells with 5 micromol/l troglitazone and 1 mmol/l of each major free fatty acid (FFA; palmitic acid, oleic acid, and linoleic acid), alone or in combination, for 48 h. After that, we evaluated glucose-stimulated insulin secretion (GSIS) and 25 mmol/l KCl-induced insulin secretion in the presence of diazoxide, which clamps membrane potential. Our results showed: (1) treatment with troglitazone for 48 h caused enhancement of GSIS, although troglitazone significantly suppressed cell viability assessed by MTT assay. (2) In cells co-treated with troglitazone and FFA, troglitazone ameliorated lipotoxicity due to FFA. (3) In the presence of 300 micromol/l diazoxide and 25 mmol/l KCl, troglitazone did not affect the recovery of GSIS in INS-1 cells. These results suggest that insulin secretion from the rat insulinoma cell line, INS-1, is modulated by troglitazone, acting somewhere in the ATP-sensitive K(+) channel pathway, possibly through PPAR gamma.

Animals↗
PubMed1999

Fatty acid composition of six varieties of dehulled African yam bean (Sphenostylis stenocarpa) flour.

The proximate and fatty acids compositions of dehulled African yam bean (Sphenostylis stenocarpa, Hochst ex A. Rich. Harms) flour were reported. The crude protein values ranged from 20.18 +/- 0.02 to 25.78 +/- 0.05 g/100 g; the ether extract values ranged from 1.93 +/- 0.05 to 10.18 +/- 0.04 g/100 g; crude fibre values ranged from 1.61 +/- 0.02 to 2.38 +/- 0.00 g/100 g; total ash ranged from 2.06 +/- 0.03 to 2.36 +/- 0.05 g/100 g and carbohydrate values ranged from 58.46 +/- 0.04 to 63.34 +/- 0.05 g/100 g. The values of the moisture content ranged from 3.20 +/- 0.03 to 7.10 +/- 0.02 g/100 g. Significant differences were found (P < 0.05) among the samples in the proximate compositions. The most concentrated fatty acids were palmitic acid (18.18 to 19.78%) < linoleic acid (28.33 to 35.16%) < stearic acid (29.01 to 36.71%). Caprylic, capric, lauric, myristic, palmitoleic, oleic, eicosenoic and erucic acids were present in small quantities with none of them recording up to 2.00% in any of the samples. However, the values of alpha-linolenic acid ranged from 2.01 to 2.96%. Significant differences were observed in the fatty acid compositions among the African yam bean dehulled seed cultivars.

Flour↗
PubMed1999

Induction of cytotoxic and helper T cell responses by modified simian immunodeficiency virus hypervariable epitope constructs.

We previously reported the broad humoral immunogenicity of peptides synthesized according to the cumulative variability of an epitope (1,16). These peptides, hypervariable epitope constructs (HECs), are designed to represent the envelope glycoproteins of several isolates of the simian immunodeficiency virus (SIV). When HEC peptides were conjugated to palmitic acid and palmitic acid ester (lipoHECs), they promoted the induction of cellular immune responses. SIV envelope lipoHEC immunization of BALB/c and ICR mice resulted in up to 80% cytotoxic T lymphocyte (CTL) lysis of SIV envelope-expressing target cells and SIV envelope-specific delayed type hypersensitivity (DTH). This DTH response was significantly higher than that of single peptide controls, and the response peaked at 24 hours. Strong SIV envelope-specific T-cell proliferative responses were also induced in mice with stimulation indexes higher than 20 for spleen cells and higher than 10 for lymph node cells. Overall, our results demonstrate that conjugation of these variable synthetic peptides to a lipid moiety results in an immunogen capable of inducing strong and cross-reactive cellular immune responses.

Amino Acid Sequence↗
PubMed1978

Intraperiplasmic growth of Bdellovibrio bacteriovorus 109J: attachment of long-chain fatty acids to escherichia coli peptidoglycan.

During the initial stages of intraperiplasmic growth of Bdellovibrio bacteriovorus on Escherichia coli, the peptidoglycan of the E. coli becomes acylated with long-chain fatty acids, primarily palmitic acid (60%) and oleic acid (20%). The attachment of the fatty acids to the peptidoglycan involves a carboxylic-ester bond, i.e., they were removed by treatment with alkaline hydroxylamine. Their linkage to the peptidoglycan does not involve a protein molecule. When the bdelloplast peptidoglycan was digested with lysozyme, the fatty acid-containing split products behaved as lipopeptidoglycan, i.e., they were extracted into the organic phase of 1-butanol:acetic acid:water (4:15) two-phase system; all of the lysozyme split products generated from normal E. coli peptidoglycan were extracted into the water phase. It is suggested that the function of the acylation reaction is to help stabilize the bdelloplast outer membrane against osmotic forces. In addition, a model is presented to explain how a bdellovibrio penetrates, stabilizes, and lyses a substrate cell.

Acylation↗
PubMed1998

Fatty acid composition of beef, pork, and poultry fresh cuts, and some of their processed products.

Numerous researchers have shown that dietary fats and oils may affect blood lipid levels and the development of cardiovascular diseases, but consumers are receiving mixed messages about the percentage of fat they should consume in their diets, and they can make proper food choices only when they have the right information. Fatty acid profiles of the meat food products in the Venezuelan diet were determined. Methyl esters were analyzed by gas chromatography on a PT 10% Silar-10C on Gas-Chrom Q 100/120 mesh column. Beef cuts presented a predominant presence of oleic acid (36.21%), palmitic (25.67%) and stearic (20.97). Oleic and palmitic acids are present in pork meat at 42.83 and 24.15% respectively; with lesser quantities of stearic and higher amounts of linoleic acid than beef. Poultry products showed a high content of linoleic (19.54%) and low content of stearic (8.22%) acids. Pork, poultry products, and beef liver presented a considerable amount of linoleic acid 11.85%, 19.54%, and 12.09%, respectively.

Animals↗
PubMed1998

[Determination of oil contents and fatty acids in seeds of Torreya Arn. in China].

OBJECTIVE: To analyze the oil contents and fatty acid composition in the seeds of Torrreya in China. METHOD: The contents and composition were determined by gravimetric analysis and GC respectively. RESULT: The oil contents in the seeds were 42.67%-54.39%. Among the fatty acids, linoleic acid and oleic acid were dominant. The unsaturated fatty acids accounted for 76.1%-82.0% of the whole fatty acids, and the major saturated fatty acids were behenic acid and palmitic acid. CONCLUSION: The oil in the seeds of Torreya is of high-quality, and the higher contents of bdhenic acid are characteristic for the oil. The development and utilization values of the seed oil in Torreya are evaluated.

Cycadopsida↗