Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STEARIC ACID”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84Linked to original sources
PubMed1983

Unsaturated fatty acids as second messengers of superoxide generation by macrophages.

Chemically elicited guinea pig peritoneal exudate macrophages respond by superoxide (O2-) production to a large number of unrelated stimulants. It has been found that 8 out of 10 stimulants also induce arachidonic acid (20:4) liberation and thromboxane synthesis. The elicitation of O2- production by most stimulants was reduced or totally suppressed by three procedures that inhibit the activity of endogenous phospholipases: the use of drug p-bromophenacyl bromide, elevation of the cellular cyclic AMP level, and the removal of extracellular Ca2+. O2- production in response to concanavalin A, wheat germ agglutinin, and fMet-Leu-Phe were exquisitely sensitive to inhibition of phospholipase activity. Exogenously applied 20:4 as well as other unsaturated fatty acids (linolenic, linoleic, and oleic) induced massive and instantaneous O2- production in a dose-dependent manner. Saturated fatty acids (stearic) and methyl esters of unsaturated acids were inactive. Lysophosphoglycerides were also inactive. Incubation of macrophages with inhibitors of cyclooxygenase or lipoxygenase did not prevent the elicitation of O2- production by stimulants or fatty acids. On the contrary, O2- formation was enhanced by indomethacin and indomethacin by itself was capable of evoking O2- generation. Treatment of 20:4 with soybean lipoxygenase did not abolish its capacity to induce O2- production; native and lipoxygenase-treated 20:4 exhibited similar dose-response ratios. Purified 15-hydroxyeicosatetraenoic acid also elicited O2- production by macrophages with a potency comparable to but not exceeding that of 20:4. Equimolar amounts of prostaglandin E2 were inactive. These findings suggest that liberation of unsaturated fatty acid (principally, 20:4) from membrane phospholipids, as a consequence of phospholipase activation, is a necessary step in the elicitation of an oxidative burst in macrophages. O2- generation is stimulated by unesterified 20:4 and, possibly, by certain metabolites of 20:4. It appears that the lipoxygenase pathway may generate metabolites with stimulating capacity while the cyclooxygenase pathway is abortive.

Animals↗
PubMed1987

Effects of composition and molecular packing on ionic properties of lipid monolayer having both cationic and anionic head groups.

The effects of composition and molecular packing on the overall ionic property of mixed monolayer involving cationic, anionic and zwitterionic lipids were studied by measuring surface potential change when the concentration of sodium or calcium ions in the aqueous substrate was varied. Those lipids used were N,N-dimethyl-N-n-hexadecyl-n-octadecyl ammonium chloride (DDAC) as cationic lipid, stearic acid (StH) or sodium docosylsulfate (SDocS) as anionic lipid, and 1,2-dipalmitoyl-sn-glycero-3-phosphorylethanolamine (PE) and 1,2-distearoyl-sn-glycero-3-phosphorylcholine (PC) as ampholytic lipids. For the equimolar mixture of StH and DDAC, the reversal of apparent charge is observed when molecular packing exceeds 3.25 X 10(-10) M/cm2. The effect is rendered to the discreteness of cationic and anionic charges in the monolayer. It was also found that the addition of 30% of PC drastically changes the ionic property of PE closer to that of PC.

Anions↗
PubMedDate not supplied

Promotion of hexagonal phase formation and lipid mixing by fatty acids with varying degrees of unsaturation.

A series of C18 and C22 fatty acids, with varying degrees of unsaturation, were tested for their ability to alter the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine. Lowering the pH from 7.4 to 6.4 greatly decreased the bilayer to hexagonal phase transition temperature of fatty acid-phosphatidylethanolamine mixtures. At pH 7.4, increasing unsaturation of the fatty acid generally increased their hexagonal phase-forming ability. However, oleic acid had somewhat greater hexagonal phase-forming capacity and docosahexaenoic acid somewhat less than would be expected for their degree of unsaturation. At pH 6.4 the difference among fatty acids was small and except for stearic acid, all had similar hexagonal phase forming tendencies. The fatty acids cause acid-induced fusion. There is little effect of fatty acid structure on membrane fusion.

Fatty Acids, Unsaturated↗
PubMed1996

Protective effects of free polyunsaturated fatty acids on arrhythmias induced by lysophosphatidylcholine or palmitoylcarnitine in neonatal rat cardiac myocytes.

Cultured, spontaneously beating, neonatal rat cardiac myocytes were used to examine the effects of various free fatty acids added to the medium perfusing the cells on lysophosphatidylcholine (LPC)- or acylcarnitine-induced arrhythmias. Perfusion of the cells with LPC or palmitoylcarnitine (2-10 microM) induced sustained tachyrhythmia with episodes of spasmodic contractures and fibrillation. Free PUFA (10-15 microM) including eicosapentaenoic acid (EPA, 20:5n-3), docosahexaenoic acid (DHA, 22:6n-3), alpha-linolenic acid (18:3n-3), arachidonic acid (AA, 20:4n-6) and linoleic acid (18:2n-6) were able to effectively prevent as well as terminate the LPC or acylcarnitine-induced arrhythmias. In contrast, monounsaturated oleic acid (18:1n-9) and saturated stearic acid (18:0) did not have such effects. The protective effects of the polyunsaturated fatty acids (PUFA) could be reversed by cell perfusion with delipidated bovine serum albumin. To determine the potential primary action by which the PUFA exert the antiarrhythmic effects, measurements of intracellular Ca2+ levels and the response of the cells to electrical pacing in the absence or presence of the PUFA were performed and the effects of verapamil (a L-type Ca2+ channel blocker), tetrodotoxin (a Na+ channel blocker) and Ca2+ ionophore A23187 on the cell contraction and the cytosolic Ca2+ levels were compared with that of the PUFA. Results suggest that an inhibitory effect on the electrical automaticity/excitability of the cardiac myocyte rather than a reduction in cytosolic Ca2+ underlie the protective effects of PUFA. In conclusion, free PUFAs are able to effectively protect the cardiac myocytes against the arrhythmias induced by low concentrations of lysophosphatidylcholine or palmitoylcarnitine.

Animals↗
PubMed1986

TLC immunostaining characterization of Clostridium botulinum type A neurotoxin binding to gangliosides and free fatty acids.

The receptor structure of Clostridium botulinum neurotoxin type A was analysed by TLC immunostaining. GQ1b was found to be the most potent receptor, and the neurotoxin also bound to GT1b and GD1a, but not to GM3, GM2, GM1, GD3, GD1b and GT1a. Optimum binding of neurotoxin to the ganglioside appeared in 0.01 M phosphate buffer (pH 7.2) containing 0.2% NaCl. Higher and lower NaCl concentrations diminished neurotoxin binding to the ganglioside. In addition, the neurotoxin was able to bind to free fatty acids. Maximum binding was observed on stearic acid and neurotoxin binding to free fatty acids was not affected by NaCl concentration.

Botulinum Toxins↗
PubMed1993

Anisodamine causes acyl chain interdigitation in phosphatidylglycerol.

The effect of anisodamine on the structure of the gel phase and the properties of the acyl chain disordering transition of dipalmitoylphosphatidylglycerol (DPPG) has been studied through high-sensitivity differential scanning calorimetry (DSC) and fluorescence polarization measurements of 16-(9-anthroyloxyl)-palmitic acid (16AP) and 3-(9-anthroyloxyl)-stearic acid (3AS), labeling, respectively, the ends and the third carbon of the acyl chains. The non-interdigitated DPPG multilamellar vesicles formed in HEPES buffer show clear fluidity gradient in their acyl chains, whereas the fluidity gradients are completely abolished in the presence of anisodamine. The DSC results showed that the phase transition temperature (Tm) of DPPG is decreased and the enthalpy (delta H) is increased by anisodamine, while the pre-transition vanishes. At 3 mM anisodamine, the delta H of DPPG reaches 9.6 kcal/mol. It can be concluded that DPPG forms an interdigitated gel phase in the presence of anisodamine. A molecular scheme for the interaction of anisodamine with DPPG is proposed.

Acylation↗
PubMed1988

Endogenous digoxin-like immunoreactivity in blood is increased during prolonged strenuous exercise.

Digoxin-like immunoreactive factors (DLIFs) in serum may represent endogenous cardiotropic agents. We determined if blood levels of these endogenous factors changed during prolonged strenuous exercise. Total and loosely protein-bound (LPB) DLIF were measured by radioimmunoassay in the serum of nine healthy subjects during prolonged exercise to exhaustion. Mean total and LPB serum levels of DLIF increased by 72% (580 to 945 pg/mL) and 63% (53 to 91 pg/mL) over baseline values in digoxin equivalents (p less than 0.01), respectively, after three hours of exercise at 70% of VO2max. The prevalent serum nonesterified fatty acids (arachidonic, linoleic, oleic, palmitic, and stearic acids) as well as hydrocortisone did not account for the observed elevations in DLIF. Percent left ventricular fractional shortening (%FS) and mean velocity of left ventricular circumferential fiber shortening (mVCF) measured echocardiographically were lower (-18.0% and -16.4%, respectively, p less than 0.05) after exercise as compared to prior to exercise. Cardiac left ventricular dysfunction as measured by %FS did correlate with blood levels of DLIF (r = -0.680, p less than 0.02). These observations may suggest a relationship between serum levels of DLIF and cardiac fatigue.

Adult↗
PubMed2004

Thermodynamic and functional properties of legumin (11S globulin from Vicia faba) in the presence of small-molecule surfactants: effect of temperature and pH.

We report on the effect of a set of water-dispersible small-molecule surfactants (the main and the longest-hydrocarbon components of which are a citric acid ester of monostearate, a sodium salt of stearol-lactoyl lactic acid, and a polyglycerol ester of stearic acid) on molecular, thermodynamic, and functional properties of the major storage protein of broad beans (Vicia faba) legumin in different molecular states (native, heated, and acid-denatured). The interaction between legumin and the surfactants has been characterized by a combination of thermodynamic methods, namely, mixing calorimetry and multiangle laser static and dynamic light scattering. It was found that hydrogen bonds, electrostatic interactions, and hydrophobic contacts provided a basis for the interactions between the surfactants and both the native and the denatured protein in aqueous medium. Intensive association of the protein molecules in a bulk aqueous medium in the presence of the surfactants was revealed by static and dynamic laser light scattering. In consequence of this, both the surface activity and the gel-forming ability of legumin increased markedly, which has been shown by tensiometry, estimation of protein foaming capacity, and steady-state viscometry. A likely molecular mechanism underlying the effects of small-molecule surfactants on legumin structure-forming properties at the interface and in a bulk aqueous medium is discussed.

Acids↗
PubMed2005

Fatty acids from seeds of Pinus pinea L.: composition and population profiling.

Pinus pinea L. is widely disseminated all over the Mediterranean Basin. Qualitatively, P. pinea fatty acid seed composition is identical and typical of the genus Pinus. This composition is made of unsaturated oil with several unusual polymethylene-interrupted unsaturated fatty acids. Linoleic acid is the major fatty acid followed by oleic, palmitic and stearic acids. Quantitatively, for all Mediterranean populations, total amounts of fatty acids seem to be fairly constant and independent from their origin. When applying principal component analysis, it seems that there is not a distinct geographical variability. Tunisian populations appear to be integral part of the Mediterranean populations without any particular structuring. Taking into account this research and the data reported in the literature, we can confirm that P. pinea expresses no significant variability. This low genetic diversity revealed by fatty acid composition can be explained by anthropogenetic diffusion of genetically homogeneous reproductive material as early as the first explorations.

Fatty Acids↗
PubMed1987

Reduced arachidonic acid levels in major phospholipids of heart muscle in the diabetic rat.

The fatty acid composition of phospholipids and triglycerides in heart muscle was examined in normal and alloxan-diabetic male Wistar rats. In diabetes the major phospholipids, phosphatidyl choline and phosphatidyl ethanolamine, showed significant changes in fatty acid composition, whereas cardiolipin and phosphatidyl serine + phosphatidyl inositol did not show marked changes in fatty acid profile. In phosphatidyl choline there was a significant diminution in arachidonic acid, 20 : 4(n-6) and palmitic acid, 16 : 0, and a corresponding increase in linoleic acid, 18 : 2(n-6), and stearic acid, 18 : 0. In phosphatidyl ethanolamine the level of 20 : 4(n-6) was significantly reduced. The diabetic heart had normal levels of individual phospholipids, whereas the triglycerides were increased by 90% and contained significantly higher levels of 18 : 2(n-6). The results confirm that diabetes is associated with a diminution in fatty acid desaturation, affecting the fatty acid composition of phosphatidyl choline in particular. These changes may be relevant to development of atherosclerosis and relative resistance to catecholamine-induced cardiac necrosis in diabetes.

Animals↗
PubMed2000

Lipid composition of the extracellular matrix of Botrytis cinerea germlings.

Six simple lipid classes (mono-, di- and tri-acylglycerols, free fatty acids, free fatty alcohols and wax esters) were identified by TLC in the extracellular matrix of Botrytis cinerea germlings and the molecular components of each class were characterized using GC-MS. The relative amounts of fatty acids and fatty alcohols within each lipid class were determined by GC-FID. Over all the lipid classes, the most abundant saturated fatty acids were palmitic (ca. 30%) and stearic acid (ca. 22%). Palmitoleic and oleic acids made up ca. 21% and 24% (respectively) of the free fatty acids, while erucic (ca. 4.1%) and linoleic (ca. 3.6%) acids were the most abundant unsaturated fatty acids in the acylglycerides. The acylglycerides also contained almost 35% long chain fatty acids (C20:0 to C28:0). Six fatty acids were identified which had odd-numbered carbon chain lengths (C15:0, C17:0, C19:0, C21:0, C23:0 and C25:0). Of these, pentacosanoic acid made up almost 14% of the fatty acids in the acylglycerides. Three methyl-branched chain fatty acids, namely isopalmitic, isoheptadecanoic and anteisopalmitic, were identified in the ECM, all in small amounts. Of the fatty alcohols identified, only palmityl and stearyl alcohols were found in the free form (ca. 57% and 43%, respectively) but arachidyl alcohol (ca. 47%) and 1-octacosanol (ca. 30%) were the most abundant fatty alcohols found in the wax ester fraction.

Botrytis↗
PubMed2002

Identification and biochemical characterisation of a protein phosphatase 5 homologue from Plasmodium falciparum.

We report the identification of a new serine/threonine phosphatase from Plasmodium falciparum at the DNA and protein levels. A 1.8 kb cDNA fragment encoding the protein phosphatase was identified via PCR amplification. The sequence has a coding capacity of 594 amino acids. Immunoblot analysis of P. falciparum extracts showed that antibodies generated against the His(6)-fusion protein recognise a protein of approximately 80 kDa. The deduced amino acid sequence shares 55% identity with a mouse protein, identified as Protein Phosphatase 5 (PP5). We show that the P. falciparum PP5 homologue (PfPP5) has all structural and functional characteristics of this class of enzymes. It contains three tetratricopeptide repeats (TPR) and a nuclear targeting sequence at its N-terminus and a highly conserved C-terminal catalytic domain. Southern blot results are compatible with the existence of PfPP5 as a single copy gene. Purified recombinant protein, like the native protein enriched from P. falciparum extracts exhibited phosphatase activity that can be enhanced by both arachidonic and oleic acids, but not by myristic or stearic acid. In addition, the activity is inhibited by okadaic acid (OA) with an IC(50) of 4 nM. Immunofluorescence microscopy has localised PfPP5 preferentially to the nucleus. The function of PfPP5 is presently unclear, but like other PP5s of many eukaryotic organisms, it may have important regulatory functions in the parasite cell cycle.

Amino Acid Sequence↗
PubMed1998

Effect of serum fatty acid composition on coronary atherosclerosis in Japan.

The serum lipid profiles of patient's with or without significant coronary stenosis diagnosed by coronary angiography and of control subjects were compared. The level of high-density-lipoprotein cholesterol and eicosapentaenoic acid were significantly lower in the patients with significant coronary stenosis than in the control subjects. It suggests that high-density-lipoprotein cholesterol and omega3 fatty acids may have a protective effect on the progress of coronary atherosclerosis. The frequency of eating dark-meat fish was positively associated with serum eicosapentaenoic acid and docosahexaenoic acid, omega3 fatty acids, and inversely associated with serum stearic acid and linoleic acid. The frequency of eating soybean products was positively associated with serum docosahexaenoic acid and inversely associated with serum linoleic acid. It is necessary to discuss a way to popularise a diet of dark-meat fish and soybean products as a means of preventing coronary heart disease.

Aged↗
PubMed2001

The effect of cold stress on ganglioside fatty acid composition and ganglioside-bound sialic acid content of rat brain subcellular fractions.

The effect of cold stress on the ganglioside fatty acid composition and sialic acid content of brain subcellular fractions and homogenate of rats was studied, the animals were kept in a cold room with 12h light-dark cycles at 3 and 10 degrees C for 2 weeks. (1) The rat brain homogenate, synaptosomes and myelin of rats exposed to 3 degrees C contained significantly higher amounts of ganglioside-bound sialic acid per mg of protein than these fractions of control rats kept at 23 degrees C; the differences were less pronounced in rats exposed to 10 degrees C. (2) A small, but significant, diminution of relative palmitic acid content and an increase of stearic acid content was found to take place in gangliosides from rat brain synaptosomes, synaptosomal plasma membranes and homogenate as a result of the exposure of animals to 3 degrees C and to a lesser extent to 10 degrees C. (3) The content of unsaturated fatty acids in gangliosides from brain subcellular fractions was approximately the same in cold exposed and control rats.

Journal Article↗
PubMed2006

Functional lipid characteristics of Turkish Tombul hazelnut (Corylus avellana L.).

The quality of crude oil extracted from Tombul (Round) hazelnut, grown in the Giresun province of Turkey, was evaluated for its fatty acid, triacylglycerol (TAG), tocol, and phytosterol compositions. Oleic acid contributed 82.78% to the total fatty acids, followed by linoleic, palmitic, and stearic acids. Among 12 TAGs separated, 11 were identified (including one unknown): LLL, OLL, PLL, OOL, POL, PPL, OOO, POO, PPO, SOO, and PSO (where P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl). The main components were OOO (71.31%), OOL (12.26%), and POO (9.45%), reflecting the high content of oleic acid present in hazelnut oil. Seven tocol isoforms (four tocopherols and three tocotrienols) and eight phytosterols as well as cholesterol were positively identified and quantified; among these, alpha-tocopherol (40.40 mg/100 g) and beta-sitosterol (134.05 mg/100 g) were predominant in hazelnut oil and contributed 78.74 and 81.28% to the total tocols and phytosterols present, respectively. Tocotrienols were detected in small amounts (1.02% to the total tocols). The crude hazelnut oil extracted from Turkish Tombul hazelnut, thus, serves as a good source of nutrients, bioactives, and health-promoting components.

Corylus↗
PubMed1965

Influence of sex and gonadal hormones on rat-liver and carcass lipids during the development of an essential fatty acid deficiency.

1. Groups of intact male and female rats and castrated rats injected with oestradiol or testosterone were given a diet containing hydrogenated coconut oil for 9 weeks, and at intervals the amounts and fatty acid compositions of the carcass and liver lipids were determined. 2. Male rats grew faster and larger, and exhibited typical external essential fatty acid deficiency symptoms sooner than did females. Testosterone-treated castrated male rats were similar to males, and oestradiol-injected castrated male rats resembled females. 3. Intact females maintained a higher linoleic acid concentration in their carcass than did males. Total amounts of carcass linoleic acid remained similar for all groups, only 200mg. being removed in 9 weeks regardless of body size. 4. The amounts of total cholesteryl esters were independent of liver size. They were higher in males and testosterone-treated castrated male rats than in females and oestrogen-treated castrated male rats. 5. Phospholipids represented about 80% of the liver lipids. The total amounts of the phospholipid linoleic acid and arachidonic acid were similar for all groups regardless of liver size, and were not affected appreciably by the deficiency. Females and oestrogen-treated castrated male rats maintained a higher proportion of phospholipid arachidonic acid for longer periods than did their male counterparts. Both the total amounts and the proportions of eicosatrienoic acid and palmitic acid were higher in males than in females. 6. Supplementation of the essential fatty acid-deficient diet with linoleic acid caused a rapid loss of eicosatrienoic acid and palmitic acid with a concomitant increase in stearic acid and arachidonic acid. 7. There were no obvious differences in the way that the essential fatty acids were metabolized or mobilized from adipose tissue of male or female rats during essential fatty acid deficiency. 8. The results indicated that the greater growth rate of the male rats caused them to require and synthesize more phospholipids than did the females. In the absence of adequate amounts of arachidonic acid, eicosatrienoic acid was substituted into the additional phospholipid. The earlier symptoms of essential fatty acid deficiency in the male rat could therefore be ascribed to the higher tissue concentrations of this unnatural phospholipid and its inability to perform the normal metabolic functions of phospholipids.

Journal Article↗
PubMed1967

The oxidation and utilization of palmitate, stearate, oleate and acetate by the mammary gland of the fed goat in relation to their overall metabolism, and the role of plasma phospholipids and neutral lipids in milk-fat synthesis.

1. Measurements were made of milk yield, mammary blood flow and arteriovenous differences of each plasma lipid fraction, and their specific radioactivities, during the infusion of [U-(14)C]stearate, [U-(14)C]oleate, [U-(14)C]palmitate and [1-(14)C]acetate into fed lactating goats. 2. Entry rates of fatty acids into the circulation were 4.2mg./min./kg. body wt. for acetate, and 0.18, 0.28 and 0.42mg./min./kg. for stearate, oleate and palmitate respectively. Acetate accounted for 23% of the total carbon dioxide produced by the whole animal, and contributed to the oxidative metabolism of the mammary gland to about the same extent. Corresponding values for each of the long-chain acids were less than 1%. 3. There were no significant arteriovenous differences of phospholipids, sterols or sterol esters, and their fatty acid composition showed no net changes during passage through the mammary gland. 4. There were large arteriovenous differences of plasma triglycerides, and their fatty acid composition showed marked changes across the gland. The proportions of palmitate and stearate fell, and that of oleate increased. 5. Arteriovenous differences of plasma free fatty acids (FFA) were small and variable, but a large fall in the specific radioactivity of each of the long-chain acids examined indicated substantial uptake of plasma FFA, accompanied by roughly equivalent FFA release from mammary tissue. The uptake of FFA was confirmed by the extensive transfer of radioactivity into milk. The FFA of milk were similar in composition and radioactivity to the milk triglyceride fatty acids, and quite unlike plasma FFA. 6. The formation of large amounts of oleic acid (18-21 mg./min.) from stearic acid was demonstrated. 7. During the terminal stages of the [(14)C]acetate infusion, milk triglyceride fatty acids of chain length C(4)-C(14) showed specific radioactivities that were 75-90% of that of blood acetate, and that of palmitate was roughly one-quarter of this value. Oleate and stearate were unlabelled. 8. The results confirmed that milk fatty acids of chain length C(4)-C(14) arise largely from blood acetate, and palmitate is derived partly from acetate and partly from plasma triglyceride, the latter fraction being almost the sole precursor of oleate and stearate.

Journal Article↗
PubMed2001

Characterization of a phospholipid antigen reacting with serum antibody in patients with peripheral neuropathies and paraproteinemia.

A phospholipid antigen that reacted with the serum antibody from a patient with peripheral neuropathy and paraproteinemia with both impaired sensory and motor functions, but not with sera from patients with only impaired sensory functions and healthy controls, was purified from bovine cauda equina as a minor component with a concentration of about 0.6 microg per gram wet-weight tissue. The structure of the phospholipid was characterized as lysophosphatidylinositol by means of thin-layer chromatography, gas-liquid chromatography, and negative-ion fast-atom-bombardment mass spectrometry. The major fatty acid component of this phospholipid was stearic acid (> 81%). Our data suggest the possible involvement of a lysophospholipid antigen in the immunopathogenesis of peripheral neuropathies with severe motor and sensory dysfunctions. There is an intriguing possibility that the difference in immunoreactivity of serum antibodies may underlie the differential clinical manifestations in patients with peripheral neuropathy and paraproteinemia.

Animals↗