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PubMed1979

Characterization of the stimulatory effects of PGF2alpha on the release of arachidonic acid.

Fibroblasts derived from a rat carrageenin granuloma were cultured in the presence of radioactive arachidonic acid, palmitic acid and linoleic acid. More than 90% of each labeled fatty acid was incorporated into a phospholipid fraction by the cells in 18 hrs. Arachidonic acid was evenly incorporated into phosphatidylcholine and phosphatidylethanolamine, while both palmitic acid and linoleic acid were almost entirely incorporated into phosphatidylcholine. The position of phosphatidylcholine where the fatty acids were incorporated was different for each fatty acid. The ratio of the amount of fatty acid incorporated into the 2-position to the amount incorporated into the 1-position of phosphatidylcholine for each fatty acid was greater than 90% for arachidonic acid, 2:1 for palmitic acid and 5:1 for linoleic acid. In the case of phosphatidylethanolamine, most arachidonic acid (greater than 90%) was incorporated into the 2-position. PGF2alpha caused the stimulation of arachidonic acid release but not of palmitic acid and linoleic acid from pre-labeled fibroblasts. The serum in the medium was completely replaceable by bovine serum albumin. The effect of PGF2Alpha increased with an increasing concentration of bovine serum albumin, suggesting that serum only acts as a "trap" for released arachidonic acid. The effect of PGF2Alpha was greater than bradykinin, and no synergistic effect was seen, although an additive effect was observed. The effect of PGF2Alpha depended on the concentration of calcium ions under magnesium-supplemented conditions.

Animals↗
PubMed2000

Lipid composition in long-day and short-day forms of the black bean aphid, Aphis fabae.

Long-day reared winged (alate) virginoparae from laboratory stock cultures which had been reared throughout larval development on bean stipules were significantly smaller (0.46+/-0.02 mg; mean+/-SEM) than short-day-reared gynoparae (0.69+/-0.04 mg; the winged autumn migrant) which completed development on intact beans. When winged virginoparae were raised from the third stadium on bean seedlings they grew larger (0.86+/-0.02 mg) but the gynoparae contained proportionally more total lipid (12.1+/-0.4%, gynoparae; 7.4+/-0.6%, stipule-reared virginoparae; 9.2+/-0.8%, seedling-reared virginoparae). Wingless aphids (apterae) were heavier, whether reared in short (0.99+/-0.03 mg) or long days (0.95+/-0.04 mg) but the lipid content was low (4.5+/-0.7% and 4.9+/-0.6%, respectively). The triacyl-, diacylglycerol and the phospholipid contents followed this trend but analysis of the fatty acid moieties of the triacylglycerides showed phenotypic differences. The ratios of myristic acid:palmitic acid were significantly higher in the winged forms than the wingless forms and were much higher in the gynoparae than the winged virginoparae. Short-day-reared wingless females also had a higher myristic acid:palmitic acid ratio than long-day-reared apterae, possibly reflecting the embryonic gynoparae maturing in their ovaries.

Journal Article↗
PubMed2004

Differential regulation by fatty acids of protein histidine phosphorylation in rat pancreatic islets.

Long-chain fatty acids (e.g. arachidonic acid) have been implicated in physiological control of insulin secretion. We previously reported histidine phosphorylation of at least two islet proteins (e.g., NDP kinase and the beta subunit of trimeric G-proteins), and suggested that such a signalling step may have regulatory roles in beta cell signal transduction, specifically at the level of G-protein activation. Since our earlier findings also indicated potential regulation by long-chain fatty acids of islet G-proteins, we undertook the current study to verify putative regulation, by fatty acids, of protein histidine phosphorylation of NDP kinase and Gbeta subunit in normal rat islets. The phosphoenzyme formation of NDP kinase was stimulated by various fatty acids in the following rank order: linoleic acid > arachidonic acid > oleic acid > palmitic acid = stearic acid = control. Furthermore, the catalytic activity of NDP kinase was stimulated by these fatty acids in the rank order of: oleic acid > arachidonic acid > linoleic acid > palmitic acid = stearic acid = control. Arachidonic acid methyl ester, an inactive analog of arachidonic acid, did not significantly affect either the phosphoenzyme formation or the catalytic activity of NDP kinase. Interestingly, arachidonic acid exerted dual effects on the histidine phosphorylation of beta subunit; it significantly stimulated the phosphorylation at 33 microM beyond which it was inhibitory. Together, these findings identify additional loci (e.g., NDP kinase and Gbeta subunit) at which unsaturated, but not saturated, fatty acids could exert their intracellular effects leading to exocytotic secretion of insulin.

Animals↗
PubMed1994

A Mutant of Arabidopsis Deficient in the Elongation of Palmitic Acid.

The overall fatty acid composition of leaf lipids in a mutant of Arabidopsis thaliana was characterized by an increased level of 16:0 and a concomitant decrease of 18-carbon fatty acids as a consequence of a single recessive nuclear mutation at the fab1 locus. Quantitative analysis of the fatty acid composition of individual lipids established that lipids synthesized by both the prokaryotic and eukaryotic pathways were affected by the mutation. Direct enzyme assays demonstrated that the mutant plants were deficient in the activity of 3-ketoacyl-acyl carrier protein synthase II; therefore, it is inferred that fab1 may encode this enzyme. Labeling experiments with [14C]acetate and lipase positional analysis indicated that the mutation results in a small shift in the partitioning of lipid synthesis between the prokaryotic and eukaryotic pathways. Synthesis of chloroplast lipids by the prokaryotic pathway was increased with a corresponding reduction in the eukaryotic pathway.

Journal Article↗
PubMed2001

[Comparative studies on the fatty acids contained in four species of medicinal plants from family Euphorbiaceae and their endophytic fungi].

OBJECTIVE: The relation of four species of medicinal plants from family Euphorbiaceae and their endophytic fungi was studied to find the source of active substances for developing new pharmaceutical resources. METHOD: The main fatty acids contained in Sapium sebiferum, Euphorbia pekinensis, Euphorbia helioscopia, Bischofia polycarpam and their 28 strains of endophytic fungi were compared and analysed by GC. RESULT: The main fatty acids of the plants are: alpha-linolenic acid, palmitic acid, linolenic acid and oleic acid. Linolenic acid, palmitic acid and oleic acid are the main fatty acids of the endophytic fungi. CONCLUSION: The fatty acids could be produced by the endophytic fungi, which could be used as a factor for identification. There are great differences at the contents of alpha-linolenic acid between the plants and their endophytic fungi, which were suggested to be related with the nutrition absorption and the relationship between the endophytes and the host plant.

Euphorbia↗
PubMed1984

Incorporation of fatty acids into phospholipids in L cells stimulated by antibody.

Binding antibodies to surface membranes stimulated incorporation of fatty acids (FA) into phospholipids of L cells. Antibodies stimulated at least a 3.4-fold greater incorporation of arachidonic acid into phosphatidylinositol than into any other class of phospholipid when compared on a molar basis (p less than 0.003). This enhanced incorporation was selective, depending on the character of the FA, because antibodies stimulated the incorporation of arachidonic acid at least 2.4-fold more than oleic acid, palmitic acid or stearic acid (p less than 0.001). Surprisingly, an antibody-stimulated incorporation of palmitic acid into sphingomyelin (SM) was at least 2.2-fold greater than that into any other class of phospholipid (p less than 0.001) and the antibody-stimulated incorporation of palmitic acid into SM was at least 60-fold greater than that of arachidonic acid, stearic or oleic acid (p less than 0.001). Nontoxic doses of ethylenediamine tetraacetic acid (EDTA), dexamethasone, 4-bromophenacylbromide and indomethacin inhibited the antibody-stimulated incorporation of arachidonic acid into cellular phospholipids, principally phosphatidylinositol (PI), and similarly inhibited the antibody stimulation of DNA synthesis. We conclude that when antibody binds to surface antigens on L cells, a rapid and selective incorporation of fatty acids into certain cellular phospholipids occurs, possibly mediated by calcium-dependent phospholipases. Degradation products of arachidonic acid, i.e., prostaglandins, may be important in these antibody stimulation events, as well. These early changes in phospholipid metabolism may serve as an important signal or mechanism for the subsequent stimulation of DNA synthesis in L cells.

Animals↗
PubMed1989

The effect of phospholipase A2 and cyclooxygenase inhibition on free fatty acids in the brain.

The levels of NEFA (oleic acid, palmitic acid, stearic acid, arachidonic acid) were studied in the brain cortex, hypothalamus and the brain stem of rat brain. Inhibition of phospholipase A2 by Delagil (Mepacrinium dichloratum CsL 3) decreased statistically significantly the values of arachidonic aci (-5.5%) in the brain cortex and the values of stearic acid (-11.2%) in the hypothalamua. The cyclooxygenase inhibition by aspirin led to a significant increase of palmitic acid (+12.7%), oleic acid (+18.7%) and arachidonic acid (+14.3%) in the hypothalamus. Total NEFA increased by 11.2%. A significant increase of palmitic acid (+26.9%), arachidonic acid (+33.9%) and of total NEFA (+22.9%) was evidenced in the brain stem. Delagil administered in combination with acetylsalicylic acid suppressed the NEFA increase observed after the application of acetylsalicylic acid alone. A statistically significant decrease was found in stearic acid (-12.6%) in the hypothalamus and in all studied NEFA in the brain stem (palmitic acid, -14.2% stearic acid -11.7%, oleic acid -3.8%, arachidonic acid -16.6% and total NEFA -11.8%).

Animals↗
PubMed2005

Candida yeast long chain fatty alcohol oxidase is a c-type haemoprotein and plays an important role in long chain fatty acid metabolism.

The industrial yeasts Candida tropicalis or Candida cloacae are able to grow on a variety of long chain alkanes and fatty acids as the sole carbon source. The complete oxidation of these substrates involves two sequential oxidative pathways: omega-oxidation, comprising the P450 alkane oxidase, a flavin-dependent membrane-bound long chain fatty alcohol oxidase [FAO] and a possible separate aldehyde oxidase [F.M. Dickinson, C. Wadforth, Purification and some properties of alcohol oxidase from alkane-grown Candida tropicalis, Biochem. J. 282 (1992) 325-331], and the beta-oxidation pathway, which utilises acylCoA substrates. We recently purified the membrane-bound long chain fatty alcohol oxidase FAO1 and confirmed it is also a c-type haemoprotein. Multiple isoforms may exist for many of these long chain fatty alcohol oxidases and the in vivo requirements for individual genes with respect to specific substrates are still being elucidated. In vitro reconstitution experiments have demonstrated that in Candida maltosa, the cytochrome P450 52A3 gene product can completely oxidise alkanes to dicarboxylic acids [U. Scheller, T. Zimmer, D. Becher, F. Schauer, W. Schunck, Oxygenation Cascade in Conversion of n-Alkanes to, -Dioic Acids Catalyzed by Cytochrome P450 52A3, J. Biol. Chem. 273 (1998) 32528-32534], potentially obviating requirements for a long chain alcohol oxidase. Here, we directly determine in vivo the role of the long chain alcohol oxidase (FAOT) in C. tropicalis, grown on a variety of substrates, followed by gene deletion. The faot double knockout has no detectable faot activity and is incapable of growth on octadecane, but it grows well on oleic acid, palmitic acid and shorter chain alkanes/fatty acids. A spontaneous mutation[s] may have occurred in the faot double gene knockout of C. tropicalis resulting in its inability to grow on oleic acid and hexadecane. The mutations demonstrate that different pathways of octadecane, hexadecane, oleic acid and palmitic acid utilisation exist in C. tropicalis.

Alcohol Oxidoreductases↗
PubMed2006

On the mechanism of palmitic acid-induced apoptosis: the role of a pore induced by palmitic acid and Ca2+ in mitochondria.

Palmitic acid (Pal) is known to promote apoptosis (Sparagna G et al (2000) Am J Physiol Heart Circ Physiol 279: H2124-H2132) and its amount in blood and mitochondria increases under some pathological conditions. Yet, the mechanism of the proapoptotic action of Pal has not been elucidated. We present evidence for the involvement of the mitochondrial cyclosporin A-insensitive pore induced by Pal/Ca(2+) complexes in the apoptotic process. Opening of this pore led to a fall of the mitochondrial membrane potential and the release of the proapoptotic signal cytochrome c. The addition of cytochrome c prevented these effects and recovered membrane potential, which is in contrast to the cyclosporin A-sensitive mitochondrial permeability transition pore. Oleic and linoleic acids prevented the Pal/Ca(2+)-induced pore opening in the intact mitochondria, this directly and significantly correlating with the effect of these fatty acids on Pal-induced apoptosis in cells (Hardy S et al (2003) J Biol Chem 278: 31861-31870). The specific probe for cardiolipin, 10-N-nonyl acridine orange, inhibited formation of this pore.

Animals↗
PubMed1976

The effects of long chain free fatty acids on human neutrophil function and structure.

Neutrophils from healthy volunteers were isolated and incubated with varying concentrations of albumin-bound long chain free fatty acids. Standard in vitro function tests including phagocytosis, bactericidal activity, and chemotaxis were performed after the incubation. It was found that unsaturated fatty acid (oleic acid) caused no changes in bactericidal activity and only moderate decreases in phagocytosis and chemotaxis at very high concentrations. Saturated fatty acid (palmitic acid) produced, at high concentrations, virtually complete inhibition of chemotaxis and moderate depression of phagocytosis and bactericidal ability. Most significantly, lower concentrations of saturated free fatty acids, within the range reported clinically in various diseases, caused a marked inhibition of chemotaxis. These functional disturbances were associated with ultrastructural alterations. Neutrophils treated with oleic acid contained numerous cytoplasmic neutral lipid droplets. Neutrophils incubated with palmitic acid showed elongated cleftlike dilations of the endoplasmic reticulum and degenerative degranulated cytoplasmic areas. It is postulated that these represent crystallization of excess saturated free fatty acids or triglyceride which interfere with chemotaxis, either mechanically or by causing cell injury.

Blood Bactericidal Activity↗
PubMed1988

Studies on the biosynthesis of beta-amino acids, the lipid moiety of iturins A, in Bacillus subtilis.

The biosynthesis of the beta-amino acid components of iturins A was studied in comparison to the biosynthesis of fatty acids. Palmitic acid was incorporated into the lipid moiety of iturins A when it was added to the culture medium of the iturin producer Bacillus subtilis. Addition of unlabeled palmitic acid enhanced the formation of straight-chain beta-amino acids and addition of valine or leucine increased the production of branched beta-amino acids. These modifications correlated with modifications in the corresponding biosynthesized fatty acids.

Anti-Bacterial Agents↗
PubMed2004

Modulation of swarming and virulence by fatty acids through the RsbA protein in Proteus mirabilis.

After sensing external signals, Proteus mirabilis undergoes a multicellular behavior called swarming which is coordinately regulated with the expression of virulence factors. Here we report that exogenously added fatty acids could act as signals to regulate swarming in P. mirabilis. Specifically, while oleic acid enhanced swarming, some saturated fatty acids, such as lauric acid, myristic acid, palmitic acid, and stearic acid, inhibited swarming. We also found that expression of hemolysin, which has been shown to be coordinately regulated with swarming, was also inhibited by the above saturated fatty acids. Previously we identified a gene, rsbA, which may encode a histidine-containing phosphotransmitter of the bacterial two-component signaling system and act as a repressor of swarming and virulence factor expression in P. mirabilis. We found that while myristic acid, lauric acid, and palmitic acid exerted their inhibitory effect on swarming and hemolysin expression through an RsbA-dependent pathway, the inhibition by stearic acid was mediated through an RsbA-independent pathway. Biofilm formation and extracellular polysaccharide (EPS) production play an important role in P. mirabilis infection. We found that RsbA may act as a positive regulator of biofilm formation and EPS production. Myristic acid was found to slightly stimulate biofilm formation and EPS production, and this stimulation was mediated through an RsbA-dependent pathway. Together, these data suggest that fatty acids may act as environmental cues to regulate swarming and virulence in P. mirabilis and that RsbA may play an important role in this process.

Bacterial Proteins↗
PubMed1977

Increased incorporation of fatty acids into phospholipids of lungs and livers of rabbits under the influence of bromhexine and ambroxol.

The incorporation of lauric acid, palmitic acid and oleic acid into phospholipids of lung and liver has been studied in tissue slices of control rabbits and of rabbits treated with bromhexine or ambroxol in doses of 10 mg/kg. A marked increase (up to 200% of the controls) of palmitic acid incorporation into phosphatidylcholine (lecithin) and phosphatidylethanolamine of the lung was found whereas the incorporation rate of palmitic acid into lecithin and phosphatidylethanolamine of the liver displayed no significant change. The incorporation of lauric acid and oleic acid into lung phospholipids was not accelerated. The observed effects were more marked in short time experiments (analysis 2 h after drug injection) than after treatements for 7 days. It is concluded that the phospholipid synthesis is stimulated by the drugs especially in the lungs. This seems to be of particular interest with respect to the surfactant system of the lung and might have some therapeutic relevance.

Ambroxol↗
PubMed1990

Injury induced by fatty acids or bile acid in isolated human colonocytes prevented by calcium.

Measurement of the modulation of the growth fraction of isolated normal colonocytes from adult subjects in primary monolayer culture was used as a sensitive quantitative assay to evaluate toxic effects of several endogenous compounds found within the colon. This assay was used to study the role of CaCl2 in blocking cell injury. When added simultaneously with the injurious agent, 5-10 mM CaCl2 blocked the toxicity of physiological concentrations of deoxycholic acid, oleic acid, palmitic acid and linoleic acid.

Calcium Chloride↗