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PubMed1987

Digestibility of cocoa butter and corn oil and their influence on fatty acid distribution in rats.

The comparative bioavailability of cocoa butter (a predominantly saturated fat) and corn oil (a predominantly unsaturated fat) was determined in male Sprague-Dawley rats by analysis of total fecal lipids following ad libitum feeding of purified diets containing 5, 10 and 20% cocoa butter or corn oil for 2 wk. Fecal lipid elimination was significantly increased (P less than 0.05) in each cocoa butter group when compared with the corresponding corn oil group, resulting in lower digestibility coefficients for cocoa butter (59-72%) than for corn oil (93-97%). Body weight gain and food intake data were similar among all treatment groups. Fecal fatty acid profiles in rats fed corn oil diets consisted primarily of 27-34% palmitic acid (16:0), 22-32% stearic acid (18:0) and 25-37% oleic acid (18:1). Palmitic, oleic and linoleic acids were also the primary fatty acids stored in epididymal fat tissue from corn oil-fed rats. In contrast, fecal fatty acids in animals fed cocoa butter diets consisted of 31-37% palmitic acid and 58-64% stearic acid; oleic acid was the major fatty acid stored in epididymal fat tissue. These results indicate that the decreased digestibility of cocoa butter is largely a result of its fatty acid composition. This reduced bioavailability of cocoa butter may be at least partially responsible for its previously described neutral effect on serum cholesterol.

Adipose Tissue↗
PubMed1993

Effects of testosterone on cholesterol levels and fatty acid composition in the rat.

The effects of testosterone treatment on cholesterol levels and its fatty acid components were studied in adult rats. Cholesterol levels increased both in the liver and in the serum of castrated rats. Androgen administration restored the normal values only in the serum. A general decrease in unsaturated and essential fatty acids in cholesterol esters was evident after testosterone administration. In the liver, only the C16:O/C16:1 ratio clearly increased after testosterone administration, which inhibited the delta 9 unsaturation of palmitic acid, but not of stearic acid. In the serum the C16:O/C16:1, C18:O/C18:1, and C18:2/C2O:4 ratios decreased after castration and were restored by testosterone. The results indicate a clear inhibition of delta 9 unsaturation of palmitic and stearic acids, of delta 5 unsaturation and elongation in organs other than the liver. No effect was evident on delta 6 unsaturation. This suggests that fatty acid unsaturations are regulated differently by testosterone in different tissues. For delta 9 unsaturation in the liver, the effect also seems to be substrate-dependent.

Analysis of Variance↗
PubMed1984

The cytosol-membrane interface of normal and sickle erythrocytes. Effect of hemoglobin deoxygenation and sickling.

The effect of deoxygenation on the amount of hemoglobin (Hb) proximal to the membranes of intact, density-fractionated normal (AA) and sickle (SS) red cells was studied by estimating resonance energy transfer efficiencies from fluorescent probes, 12-(9-anthroyloxy)stearic acid or 2-(9-anthroyloxy)stearic acid, in the outer lipid layer to cytoplasmic hemes. For each density fraction, heme concentrations at the cytosol-membrane interface (hb) were derived from the probe decay rates for ghosts and intact cells, measured by front-face fluorometry, and compared with mean cell heme concentrations (hc). With AA cells, hb/hc varied little with cell density; a 33% drop in hb on deoxygenation is attributable to organic phosphate binding to deoxy-Hb. With oxy-SS cells, hb/hc increased with cell density to twice the values for AA cells, but SS ghosts showed no evidence of increased probe quenching by membrane-bound Hb. On deoxygenation, hb for each SS density fraction fell (reversibly) to one-third the oxy value. The finding that deoxy-HbS withdraws from the membrane bilipid layer much more than deoxy-HbA is consistent with evidence for an increased net negative charge on deoxy-HbS polymers and/or the suggestion that the cytoskeleton, readily penetrated by monomeric Hb, presents a barrier to polymeric HbS. Membrane-associated HbS is therefore thought to play an unimportant role in polymerization.

Cytosol↗
PubMed1987

Alterations of the composition and size of the free fatty acid pool of Tetrahymena responding to low-temperature stress.

Cells of Tetrahymena mimbres (formerly T. pyriformis NT-1) in midlogarithmic growth under isothermal conditions (at 39 degrees C) contained a very small, compositionally discrete pool of free fatty acids, principally (60.6% of the total free fatty acid mass) palmitic and stearic acids. The composition, degree of unsaturation, and size of this free fatty acid pool were rapidly (15 min or less) altered in response to chilling. During the acclimation period following chilling to 15 degrees C, the size of the free fatty acid pool increased from a mean value of 15.5 nmol free fatty acid/mumol lipid phosphorus in 39 degrees C cells to 24.2 nmol free fatty acid/mumol lipid phosphorus. The degree of free fatty acid saturation rapidly increased over the initial hour following the onset of hypothermal conditions, but by 24 h the unsaturated free fatty acid/saturated free fatty acid ratio was 0.35 (equivalent to a 2.7-fold increase in unsaturation relative to 39 degrees C controls (unsaturated/saturated ratio = 0.13) and 4.4-fold greater than cells acclimated for 1 h (unsaturated/saturated ratio = 0.08)). By 24 h the percentage of palmitic and stearic acids had decreased to 45.6%. Similar, and in some instances more pronounced, changes were observed to occur in triacylglycerol-bound fatty acids. Modulation of steady-state free fatty acid composition could also be achieved by the addition of exogenous fatty acids to the growth medium. The ability to manipulate the level of intracellular free fatty acids should prove to be a valuable experimental tool in determining how specific fatty acids regulate various lipid-modifying enzymes.

Acclimatization↗
PubMed1985

Structural changes of rat liver microsomal membranes induced by the oral administration of carbon tetrachloride. 31P-NMR and spin-label studies.

The acute effects of carbon tetrachloride (CCl4) on the membrane structure of rat liver microsomes were studied using 31P-NMR and spin-labeling techniques. 31P-NMR spectra of rat liver microsomes were not changed appreciably after the oral administration of CCl4, indicating that the surface structures of microsomal membranes probably are not influenced by the oral administration of CCl4. Four different spin-labeled stearic acids, 5-(N-oxyl-4',4'-dimethyloxazolidine)-stearic acid (5SLS), its methyl ester (5SLSM), 12-(N-oxyl-4',4'-dimethyloxazolidine)-stearic acid (12SLS) and its methyl ester (12SLSM), were used for the estimation of membrane fluidity. The apparent rotational correlation time of 12SLS decreased from 4.0 nsec to 3.0 nsec after the oral administration of CCl4, while the order parameter of 5SLS did not change. The results suggest that CCl4 or its metabolites increase the membrane fluidity of liver microsomes primarily at hydrophobic regions rather than at the surface layer. The ESR spectrum of 5SLSM in microsomal membranes comprised two different signals; one was an anisotropic signal and the other was a rather isotropic one. The ratio of the anisotropic signal to the isotropic one decreased markedly after the oral administration of CCl4 and depended on the dose of CCl4. The suitability of this ESR technique with 5SLSM for the estimation of membrane damage is discussed.

Administration, Oral↗
PubMedDate not supplied

[The fatty acid composition of the gangliosides in different parts of the vertebrate brain].

Comparative studies on gangliosides from the brain of higher (mammals, birds) and lower (amphibians, cartilaginous and teleost fishes) vertebrates indicate that for each of the parts of the brain the same regularities in changes of fatty acid composition are typical as for the total brain in a series of vertebrates. All brain structures of the mammalian brain exhibit higher saturation of ganglioside fatty acids, higher content of stearic acid (C18:0) and lower relative content of long chain (C22-C24) fatty acids, especially that of C24:1, as compared to the corresponding brain structures of lower vertebrates. Fatty acid composition in birds is more close to mammalian one with respect to some of the features, while with respect to the other ones it occupies an intermediate position between lower vertebrates and mammals. In the series more phylogenetically ancient--more recent brain parts (medulla oblongata--midbrain--forebrain), the content of content of stearic acid and the degree of saturation ganglioside fatty acids increase, whereas the relative content of acids with a long chain (C22-C24) in them decreases (with the exception of amphibians). In all the brain structures of higher elasmobranch fishes, fatty acid composition of gangliosides exhibits more progressive features of chemical organization as compared to that in homologous structures of lower elasmobranch fishes.

Animals↗
PubMed1998

Protein and fatty acid composition of caveolae from apical plasmalemma of aortic endothelial cells.

In endothelial cells (EC), caveolae or plasmalemmal vesicles (PVs) represent a structurally and biochemically specialized membrane microdomain. Since few data are available on the biochemical composition of PVs of large vessel endothelium, we have designed experiments to isolate this domain and to analyze its chemical components. A highly purified apical membrane fraction was obtained from cultured bovine aortic EC by using cationic colloidal silica (silica-ap), or the EC were surface-radioiodinated and a cell homogenate was prepared. Detergent treatment (Triton X-100; TX) and mechanical disruption of both the silica-ap fraction and cell homogenate followed by ultracentrifugation on a sucrose gradient gave detergent-soluble and detergent-insoluble membranous fractions. The lowest density TX-insoluble fraction appeared morphologically as distinct vesicles (caveolae; 60 nm average diameter; PVs fraction). Biochemical characterization of the PVs fraction (by comparison with the soluble fraction) revealed the presence, at high concentration, of specific caveolar markers, viz., caveolin (both isoforms, the 24-kDa form being conspicuously more abundant) and Ca2+-ATPase. By contrast, angiotensin-converting enzyme and alkaline phosphodiesterase were present almost exclusively in the TX-soluble fraction. The glycoproteins in the PVs fraction were of apparent molecular weights 52, 68, 95, and 114 kDa. Analysis of the fatty acid composition revealed more palmitoleic and stearic acid in the PVs fraction then in the TX-soluble fraction. Thus, in comparison with the plasmalemma proper, the PVs fraction (1) is detergent-insoluble; (2) contains caveolin in two isoforms; (3) contains Ca2+-ATPase at high concentration; (4) contains a set of specific glycoproteins; and (5) is enriched in palmitoleic and stearic acids.

Animals↗
PubMed1993

Effects of the individual saturated fatty acids on serum lipids and lipoprotein concentrations.

A mixture of dietary saturated fatty acids raises the serum total cholesterol concentrations compared with a diet of isoenergetic amounts of carbohydrates. Saturated fatty acids are not all equally hypercholesterolemic: stearic acid (18:0) and saturated fatty acids with < 12 carbon atoms are thought not to raise serum cholesterol concentrations. This suggest that the cholesterol-raising properties of saturated fatty acids should be attributed solely to lauric acid (12:0), myristic acid (14:0), and palmitic acid (16:0). These three saturated fatty acids, however, may have different effects on serum total-cholesterol concentrations as well. Results from controlled dietary experiments suggest that lauric acid (12:0) is less, and myristic acid (14:0) probably more, hypercholesterolemic than palmitic acid (16:0). Effects of the different saturated fatty acids on the distribution of cholesterol over the various lipoproteins are largely unknown, but it is suggested that stearic acid lowers HDL cholesterol concentrations relative to other saturated fatty acids. At present, however, too many questions are unanswered to quantitate these differences.

Cholesterol↗
PubMed2001

Lipase production in two-step fed-batch culture of organic solvent-tolerant Pseudomonas aeruginosa LST-03.

Efficient lipase production by two-step fed-batch culture of an organic solvent-tolerant bacterium, Pseudomonas aeruginosa LST-03, was investigated. When FB synthetic medium was used in flask culture, no lipase activity was detected, whereas lipase was produced at 2.3 I.U./ml in C2 complex medium. However, lipase production was induced in FB medium when a fatty acid was added to the culture broth in the stationary phase. Among fatty acids tested, long chain saturated fatty acids, such as C18 (stearic acid) and C20 (arachidic acid), were found to function as effective inducers for the production of lipase, giving an activity level almost the same as that obtained in C2 medium in flask culture. Two-step lipase production, comprised of a growth phase in fed-batch mode and a production phase in which lipase was induced by the addition of 5% (v/v) stearic acid, was carried out in a jar-fermentor. In the growth phase, the maximum cell concentration at 16 h was only 20 in terms of the optical density at 660 nm (OD660), and a low level of lipase production (8 I.U./ml) was obtained after 167 h. This was considered to be due to the exhaustion of several medium components brought about by the use of an unsuitable medium or feeding solution. After analyzing the contents of the compounds in the culture broth by inductively coupled plasma spectrometry for metal ions and HPLC for anions, a modified FB medium was designed. When this modified FB medium was used in two-step fed-batch culture, the maximum cell concentration reached an OD660 of 55 (30.2 g-dry cells/l) at 16.5 h, and lipase was produced at 96 I.U./ml after 35 h, which is approximately 40 times higher than the production level obtained in flask culture using C2 medium.

Journal Article↗
PubMed1995

Regulation of lysophospholipase activity of the 85-kDa phospholipase A2 and activation in mouse peritoneal macrophages.

The regulation of the lysophospholipase activity of the 85-kDa cytosolic phospholipase A2 (PLA2) was studied in vitro and in stimulated macrophages. Bovine serum albumin was found to inhibit lysophospholipase activity of the recombinant 85-kDa PLA2 when assayed at a relatively low substrate concentration. Inhibition could be reversed if the substrate concentration was increased or if Ca2+ was present in the assay. Incubation of recombinant enzyme with macrophage membranes and lipid extracts from macrophage membranes resulted in the release of arachidonic acid, as well as, stearic acid, which is enriched at the sn-1 position of macrophage phospholipids. This suggests that with a bilayer substrate the PLA2 can sequentially deacylate the sn-2 then sn-1 acyl groups. This was verified by demonstrating that the phospholipids, phosphatidylcholine and phosphatidylinositol, were hydrolyzed to glycerophosphocholine and glycerophosphoinositol by incubation with recombinant 85-kDa PLA2. The 85-kDa enzyme was identified as the main lysophospholipase activity in mouse peritoneal macrophage cytosols. Addition of Ca2+ to the assay enhanced activity, but this effect decreased as the substrate concentration was increased. Incubation of macrophages with zymosan increased the lysophospholipase activity of the 85-kDa PLA2 in cytosols. Phosphorylation of recombinant PLA2 with mitogen-activated protein kinase resulted in an increase in lysophospholipase, as well as, PLA2 activity. In macrophages stimulated with zymosan release of stearic acid (18:0) and palmitic acid (16:0) was observed in addition to arachidonic acid (20:4). These results are consistent with a role of the 85-kDa PLA2 in regulating lysophospholipid levels in macrophages during zymosan stimulation.

Animals↗
PubMed1980

Fatty acid desaturation in lung: inhibition by unsaturated fatty acids.

The activity of the enzyme system involved in desaturation of palmitic and stearic acid has been examined in lungs of rats fed fat-free diets supplemented either with 4% safflower oil (controls) or 4% tripalmitin (essential fatty acid (EFA) deficient) both in vivo and in vitro in lung slices. Desaturation, as measured by appearance of 14C-labeled monounsaturated fatty acid in pulmonary total lipid and phospholipids, was significantly greater in vivo and in vitro in lung tissue from EFA-deficient rats. In vitro peincubation of lung slices for 1 to 4 hr with 1 mM oleic, linoleic, or linolenic acid reduced the extent of desaturation of [1-14C]-stearic acid significantly in both dietary groups, but the effect was greater in EFA-deficient tissues. The effect of linoleic acid was always greater than that of oleic acid. Preincubation with palmitic acid and 16,16-dimethyl PGE2 was without effect. Thus: 1) EFA deficiency has been shown to enhance desaturation of palmitic and stearic acid in lung; 2) in vitro addition of linoleic or linolenic acid inhibited desaturation significantly; and 3) oleic acid was inhibitory but to a lesser and more variable extent. Palmitic acid was not inhibitory.

16,16-Dimethylprostaglandin E2↗
PubMed2001

Antimicrobial edible packaging based on cellulosic ethers, fatty acids, and nisin incorporation to inhibit Listeria innocua and Staphylococcus aureus.

Edible cellulosic films made with hydroxypropylmethylcellulose (HPMC) have proven to be inadequate moisture barriers. To improve its water vapor barrier properties, different hydrophobic compounds were incorporated into the HPMC matrix. Some fatty acids and derivatives were included into the film-forming solution prior to film formation. Stearic acid was chosen because of its high capacity to reduce significantly the water vapor transmission rate. Antimicrobial activity of edible HPMC film was obtained by the incorporation of nisin into the film-forming solution. Nisin is an antimicrobial peptide effective against gram-positive bacteria. The inhibitory activity of this bacteriocin was tested for inhibition of Listeria innocua and Staphylococcus aureus. The use of stearic acid was observed to reduce the inhibitory activity of active HPMC film against both selected strains. This phenomenon may be explained by electrostatic interactions between the cationic nisin and the anionic stearic acid. Further studies showed that antimicrobial activity of film varied with the nature of the hydrophobic compound incorporated, in decreasing order: film without lipid, methylstearate film, and stearic acid film. This corroborated the idea of electrostatic interactions.

Anti-Bacterial Agents↗
PubMed1995

Erythrocyte membrane fatty acid profile in patients with primary carcinoma of the gallbladder.

Erythrocyte fatty acids were determined in patients with gall stones and carcinoma of the gallbladder. Significantly low levels of myristic acid (P < 0.01) and stearic acid (P < 0.001) and significantly high levels of palmitoleic acid (P < 0.05) and oleic acid (P < 0.01) were observed in cancer patients. Arachidonic and linolenic acid were significantly high in gallstone patients, but there was no significant difference in the lauric acid and palmitic acid levels. Thus an altered lipid metabolism in cancer patients suggest existence of a possible association between gallstones, fatty acids, and carcinoma of the gallbladder.

Cholelithiasis↗
PubMed1998

Interaction of free fatty acids with human leptin.

Relatively high concentrations of leptin are present in plasma and it is thought to play a major role in lipid homeostasis. Leptin is reported to lower tissue triglyceride content by increasing intracellular oxidation of free fatty acids (FFA). However very little is known regarding the interaction between leptin and plasma FFA. We studied the interaction of FFA with leptin using a direct radiolabelled fatty acid binding assay, a fluorescence assay, electrophoretic mobility and autoradiobinding. All these data indicate that binding of FFA with leptin is reversible and shows a positive co-operativity. The binding of FFA to leptin produces a change in the pI value of the leptin and also increased the electrophoretic mobility of the protein in native polyacrylamide gels. The change in leptin's electrophoretic mobility depends on the chain length and the number of double bonds of the fatty acid, as stearic acid, 18:0, had no effect whereas oleic acid, 18:1n-9, linoleic acid, 18:2n-6, arachidonic acid, 20:4n-6, and docosahexaneoic acid, 22:6n-3, affected leptin's mobility to different degrees. The physiological implication of leptin-FFA interaction is not known, however the interaction may depend on the plasma FFA composition and concentration which are known to vary in different pathological/physiological conditions.

Carrier Proteins↗
PubMed1993

Lipid and fatty acid analysis of the Plodia interpunctella granulosis virus (PiGV) envelope.

Virus envelope was isolated from Plodia interpunctella granulosis virus, produced in early fourth-instar larvae. Both polar and neutral lipids were analyzed by two-dimensional thin-layer chromatography. Fatty acid composition of various individual neutral and polar lipids was determined by gas-liquid chromatography. The major components of envelope neutral lipid were diacylglycerols. Palmitic acid and stearic acid were the major saturated fatty acids in both polar and neutral lipids. Whereas palmitoleic acid was the major unsaturated fatty acids in neutral lipids, oleic acid was the major unsaturated fatty acid in the polar lipids.

Baculoviridae↗
PubMed1992

The effect of arachidonic acid on the M current of NG108-15 neuroblastoma x glioma hybrid cells.

The M current, IM, a voltage-dependent non-inactivating K+ current, was recorded in NG108-15 neuroblastoma x glioma hybrid cells, using the whole-cell mode of the patch-clamp technique. We studied the effect of arachidonic acid, other fatty acids and inhibitors of the arachidonic acid metabolism. In relatively high concentrations (25-50 microM) arachidonic acid first increased and later decreased the current, Ih, which holds the membrane potential at -30 mV and mainly flows through open M channels. It shifted the midpoint potential, Vo, of the relation between M conductance, gM, and membrane potential, V, to more negative values and decreased the maximum conductance gM and the time constant tau M. In smaller concentrations (5-10 microM) arachidonic acid merely decreased Ih and gM with little effect on Vo and tau M. Eicosatetraynoic acid and docosahexaenoic acid acted similarly to arachidonic acid whereas stearic acid had no effect. Of the three enzyme inhibitors studied, nordihydroguaiaretic acid acted similarly to arachidonic acid. i.e. caused a biphasic change in Ih. Indomethacin and quinacrine caused, respectively, a pure increase and a pure decrease of Ih and gM. Possible explanations are build-up of internally produced arachidonic acid, depletion of eicosanoid products or an inhibitory effect unrelated to arachidonic acid metabolism.

Arachidonic Acid↗
PubMed1977

[Thermal inactivation and storage behavior of technologically important enzymes. III. Effect of reagents added to peroxidase and lipoxygenase].

The influence of milieu factors on the thermal inactivation of peroxidase and lipoxigenase was investigated. Cationogenic, anionogenic, non-ionogenic and amphoteric tensides were more or less effective in inactivating horseradish peroxidase. Most effective in this respect were lecithine and monoglyceride, both capable of swelling in water. In presence of lecithine, peroxidase was inactivated already at 0 degrees C and pH 4.0. Linoleic acid was more efficient in an oxygen stream than in presence of nitrogen, in a stream of nitrogen its influence was comparable to oleic acid. This suggests an additional effect by lipid peroxides which are formed of linoleic acid under the heating process. Tensides prevented the regeneration of the heated peroxidase. In the case of lipoxigenase, the authors investigated the influence of lecithine and various fatty acids on the thermal inactivation at 60 degrees and pH 7.0. Lecithine accelerated the inactivation less distinctly than with peroxidase. The accelerated the inactivation less distinctly than with peroxidase. The accelerating effect of the fatty acids decreased in the order oleic acid, linoleic acid, palmitic acid, myristic acid and stearic acid.

Drug Stability↗
PubMed1977

Benzoyl cyanide in the defensive secretion of polydesmoid millipeds.

A novel cyanogenetic compound benzoyl cyanide, was isolated from the defensive secretion of 3 polydesmoid millipeds (Pseudopolydesmus seratus, Apheloria corrugata and A. trimaculata). The secretion of the 3 species also contains mandelonitrile and benzaldehyde, and that of P. serratus contains mandelonitrile benzoate, benzoic acid, isovaleric acid, myristic acid and stearic acid.

Animals↗