linoleic-acid and ricinoleic-acid

Numerous Δ12-, Δ15- and multifunctional membrane fatty acid desaturases (FADs) have been identified in fungi, revealing great variability in the enzymatic specificities of FADs involved in biosynthesis of polyunsaturated fatty acids (PUFAs). Here, we report gene isolation and characterization of novel Δ12/Δ15- and Δ15-FADs named CpFad2 and CpFad3, respectively, from the opportunistic pathogenic yeast Candida parapsilosis. Overexpression of CpFad3 in Saccharomyces cerevisiae strains supplemented with linoleic acid (Δ9,Δ12-18:2) and hexadecadienoic acid (Δ9,Δ12-16:2) leads to accumulation of Δ15-PUFAs, i.e., α-linolenic acid (Δ9,Δ12,Δ15-18:3) and hexadecatrienoic acid with an unusual terminal double bond (Δ9,Δ12,Δ15-16:3). CpFad2 produces a range of Δ12- and Δ15-PUFAs. The major products of CpFad2 are linoleic and hexadecadienoic acid (Δ9,Δ12-16:2), accompanied by α-linolenic acid and hexadecatrienoic acid (Δ9,Δ12,Δ15-16:3). Using GC/MS analysis of trimethylsilyl derivatives, we identified ricinoleic acid (12-hydroxy-9-octadecenoic acid) as an additional product of CpFad2. These results demonstrate that CpFAD2 is a multifunctional FAD and indicate that detailed analysis of fatty acid derivatives might uncover a range of enzymatic selectivities in other Δ12-FADs from budding yeasts (Ascomycota: Saccharomycotina).

Topics: Amino Acid Sequence; Candida; Fatty Acid Desaturases; Fatty Acids, Unsaturated; Linoleic Acid; Molecular Sequence Data; Phylogeny; Ricinoleic Acids; Saccharomyces cerevisiae

Sixteen Pseudomonas aeruginosa strains, including patent strain NRRL B-18602, three recent isolates from composted materials amended with ricinoleic acid, and 12 randomly selected from the holdings of the ARS Culture Collection, were examined for their fatty acid converting abilities. The study examined the bioconversion of oleic acid to 7,10-dihydroxy-8( E)-octadecenoic acid (DOD) and ricinoleic acid to 7,10,12-trihydroxy-8( E)-octadecenoic acid (TOD). A new DOD-like compound from linoleic acid was observed. All strains except NRRL B-247 exhibited varying levels of DOD production. NRRL B-1000, NRRL B-18602 and NRRL B-23258 with yields up to 84% were among the best DOD producers. TOD production generally paralleled DOD production at a relatively lower yield of up to 15%. Strains NRRL B-1000 and NRRL B-23260 were the best TOD producers. A DOD-like product in low yields was obtained from linoleic acid. The fatty acid bioconversion capability was related neither to growth rate nor to variation in the greenish pigmentation of the strains. Production of significant quantities of DOD and TOD from oleic and ricinoleic acids, respectively, appeared to be a characteristic trait of P. aeruginosa strains. A number of highly effective strains for DOD production were identified.

Topics: Culture Media; Environmental Microbiology; Fermentation; Humans; Hydroxy Acids; Linoleic Acid; Oleic Acid; Oleic Acids; Pseudomonas aeruginosa; Pseudomonas Infections; Ricinoleic Acids

Expression of a cDNA encoding the castor bean ( Ricinus communis L.) oleate Delta12-hydroxylase in the developing seeds of Arabidopsis thaliana (L.) Heynh. results in the synthesis of four novel hydroxy fatty acids. These have been previously identified as ricinoleic acid (12-hydroxy-octadec- cis-9-enoic acid: 18:1-OH), densipolic acid (12-hydroxy-octadec- cis-9,15-enoic acid: 18:2-OH), lesquerolic acid (14-hydroxy-eicos- cis-11-enoic acid: 20:1-OH) and auricolic acid (14-hydroxy-eicos- cis-11,17-enoic acid: 20:2-OH). Using mutant lines of Arabidopsis that lack the activity of the FAE1 condensing enzyme or FAD3 ER Delta-15-desaturase, we have shown that these enzymes are required for the synthesis of C20 hydroxy fatty acids and polyunsaturated hydroxy fatty acids, respectively. Analysis of the seed fatty acid composition of transformed plants demonstrated a dramatic increase in oleic acid (18:1) levels and a decrease in linoleic acid (18:2) content correlating to the levels of hydroxy fatty acid present in the seed. Plants in which FAD2 (ER Delta12-desaturase) activity was absent showed a decrease in 18:1 content and a slight increase in 18:2 levels corresponding to hydroxy fatty acid content. Expression of the castor hydroxylase protein in yeast indicates that this enzyme has a low level of fatty acid Delta12-desaturase activity. Lipase catalysed 1,3-specific lipolysis of triacylglycerol from transformed plants demonstrated that ricinoleic acid is not excluded from the sn-2 position of triacylglycerol, but is the only hydroxy fatty acid present at this position.

Topics: Acetyltransferases; Arabidopsis; Fatty Acid Desaturases; Fatty Acid Elongases; Fatty Acids; Fatty Acids, Unsaturated; Gene Expression Regulation, Developmental; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Linoleic Acid; Mutation; Oleic Acid; Ricinoleic Acids; Seeds; Triglycerides

Bacillus sphaericus species are mesophilic round-spored organisms that readily utilize fatty acid-based surfactants during growth, but their ability to modify fatty acids is unknown. Among 57 B. sphaericus-like strains tested for fatty acid transformation activity in Wallen fermentation (WF) medium, ten converted oleic acid to a new product determined by gas chromatography - mass spectrometry (GC-MS) to be 10-ketostearic acid (10-KSA). Additionally, a few other strains converted ricinoleic acid and linoleic acid to new products that remain to be characterized. Unlike most microbial hydrations of oleic acid, which produce a mixture of 10-KSA and 10-hydroxystearic acid, the conversion of oleic acid by B. sphaericus strains was unique in that 10-KSA was the sole reaction product. By replacing dextrose with sodium pyruvate in WF and adjusting to pH 6.5, conversion of oleic acid to 10-KSA by strain NRRL NRS-732 was improved from about 11% to more than 60%. Using the defined optimal conditions, the conversion reaction was scaled up in a stirred-batch reactor by using technical-grade oleic acid as substrate. This is the first report on the characterization of fatty acid conversions by B. sphaericus species.

Topics: Bacillus; Culture Media; Fatty Acids; Hydrogen-Ion Concentration; Linoleic Acid; Oleic Acid; Ricinoleic Acids; Stearic Acids; Time Factors

Production of conjugated linoleic acids (CLA) using castor oil as starting material involves conversion of ricinoleic acid to methyl 12-mesyloxy-octadec-9-enoate (MMOE) followed by dehydration. This process usually uses 1,8-diazabicyclo-(5.4.0)-undec-7-ene (DBU) as an expensive dehydrating reagent. The present study reports that potassium hydroxide (KOH) can serve as a dehydrating reagent in replacement of DBU. The results showed that conversion of MMOE to CLA catalyzed by KOH was an efficient reaction, with a 77% conversion efficiency at 80 degrees C. The CLA isomeric profile produced in KOH-catalyzed dehydration reaction was similar to that catalyzed by DBU. The CLA mixture produced in KOH-catalyzed dehydration of MMOE at 80 degrees C contained 72% 9c,11t-18:2 and 26% 9c,11c-18:2 while in that catalyzed by DBU, 9c,11t-18:2 and 9c,11c-18:2 accounted for 78 and 16%, respectively. It was found that the temperature of dehydration was an important factor in the determination of CLA isomer composition and yield of conversion. Elevating the temperature from 78 to 180 degrees C decreased not only the conversion efficiency but also production of total c,t-18:2 and c,c-18:2 isomers regardless of dehydration catalyzed by either DBU or KOH. It is concluded that KOH may replace DBU as a dehydrating reagent in conversion of MMOE to CLA when the reaction conditions are optimized.

Topics: Castor Oil; Catalysis; Hydroxides; Indicators and Reagents; Isomerism; Linoleic Acid; Potassium Compounds; Ricinoleic Acids

Ricinoleic acid (12-hydroxy-cis-9-octadecaenoic acid) was an effective substrate for conjugated linoleic acid (CLA) production by washed cells of Lactobacillus plantarum AKU 1009a. The CLA produced was a mixture of cis-9,trans-11- and trans-9,trans-11-octadecadienoic acids. Addition of alpha-linolenic acid to the culture medium increased the CLA productivity of the washed cells. In the presence of lipase, castor oil, in which the main fatty acid component is ricinoleic acid, also was a substrate for CLA.

Topics: Castor Oil; Culture Media; Lactic Acid; Lactobacillus; Linoleic Acid; Ricinoleic Acids

Higher plants exhibit extensive diversity in the composition of seed storage fatty acids. This is largely due to the presence of various combinations of double or triple bonds and hydroxyl or epoxy groups, which are synthesized by a family of structurally similar enzymes. As few as four amino acid substitutions can convert an oleate 12-desaturase to a hydroxylase and as few as six result in conversion of a hydroxylase to a desaturase. These results illustrate how catalytic plasticity of these diiron enzymes has contributed to the evolution of the chemical diversity found in higher plants.

Topics: Amino Acid Substitution; Arabidopsis; Binding Sites; Catalysis; Fatty Acid Desaturases; Fatty Acids; Fatty Acids, Unsaturated; Genes, Plant; Hydroxy Acids; Hydroxylation; Linoleic Acid; Mixed Function Oxygenases; Mutagenesis, Site-Directed; Oleic Acid; Oxidoreductases Acting on CH-CH Group Donors; Plant Proteins; Plants; Plants, Genetically Modified; Recombinant Proteins; Ricinoleic Acids

Unabsorbed dietary unsaturated fatty acids may cause diarrhea in patients with steatorrhea, but their ability to cause colonic fluid secretion is not known. The present study investigated the effect of several dietary long-chain unsaturated fatty acids on colonic absorption and morphology in the rat colon in vivo. The fatty acids tested induced concentration-dependent net water secretion. The ability of these fatty acids to induce net water secretion varied as follows: linolenic acid (18:3) > linoleic acid (18:2), ricinoleic acid (18:1 OH) > oleic acid (18:1), palmitoleic acid (16:1). Net absorption of sodium and chloride were decreased in fatty acid perfusions. Mucosal activity of sodium potassium adenosine triphosphate and adenyl cyclase were not significantly altered by fatty acids. Epithelial cell damage was noted and correlated with the ability of the fatty acid to induce fluid secretion. Unsaturated fatty acids induce epithelial cell damage and fluid secretion in the colon, their effect being related to the degree of unsaturation.

Topics: Adenylyl Cyclases; alpha-Linolenic Acid; Animals; Colon; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Hydroxylation; In Vitro Techniques; Intestinal Absorption; Intestinal Mucosa; Linoleic Acid; Linoleic Acids; Oleic Acid; Oleic Acids; Potassium; Rats; Rats, Inbred Strains; Ricinoleic Acids; Sodium; Sodium-Potassium-Exchanging ATPase

The seed oil of the plant Ixiolaena brevicompta is a rich source of crepenynic acid (octadec-cis-9-en-12-ynoic acid), which has been linked with extensive sheep mortalities in Western New South Wales and Queensland, Australia. A number of acetylenic fatty acids have been found to interfere with lipid and fatty acid metabolism and inhibit cyclooxygenase and lipoxygenase enzymes in a variety of tissues. We have investigated the effects of crepenynic acid and ximenynic acid (octadec-trans-11-en-9-ynoic acid) on leukotriene B4 and thromboxane B2 production in rat peritoneal leukocytes and compare them with non-acetylenic compounds linoleic and ricinoleic acids. In concentrations ranging from 10 to 100 microM linoleic acid and ricinoleic acid had only minimal effects on leukotriene B4 and thromboxane B2 production in ionophore-stimulated cells. Ximenynic acid gave dose-dependent inhibition of leukotriene B4, thromboxane B2 and 6-ketoprostaglandin F1 alpha production. Ximenynic acid appears to be a more effective inhibitor of leukotriene B4 than crepenynic acid with an IC50 of 60 microM compared to 85 microM. On the other hand, crepenynic acid is a much more effective inhibitor of the cyclooxygenase products, having an IC50 for thromboxane B2 of less than 10 microM. Both acetylenic fatty acids inhibited phospholipase activity in these cells by 40-50% at a concentration of 100 microM but had no inhibitory effect at 10 microM. These results indicate that crepenynic acid and ximenynic acid differentially inhibit the cyclooxygenase and lipoxygenase products of stimulated leukocytes, and that at high doses of these fatty acids the effect on these products may be partially due to inhibition of phospholipase A2.

Topics: Alkynes; Animals; Cyclooxygenase Inhibitors; Leukocytes; Leukotriene B4; Linoleic Acid; Linoleic Acids; Lipoxygenase Inhibitors; Oleic Acids; Peritoneal Cavity; Phospholipases; Rats; Ricinoleic Acids; Thromboxane B2

1. Ricinoleic acid is shown to be synthesized in the immature castor bean seed only after 3-4 weeks from the time of fertilization. 2. Synthesis occurs both in the isolated embryo and the endosperm. 3. Linoleic acid does not act as precursor of ricinoleic acid in the isolated bean embryo. 4. Oleic acid is shown to be the direct precursor of ricinoleic acid. 5. The reaction does not use molecular oxygen. This suggests that ricinoleic acid is not a precursor of linoleic acid.

Topics: Acetates; Chromatography; Fatty Acids; Linoleic Acid; Lipid Metabolism; Oleic Acid; Oleic Acids; Research; Ricinoleic Acids; Ricinus; Ricinus communis; Seeds

Topics: Animals; Fatty Acids; Lanolin; Linoleic Acid; Rats; Ricinoleic Acids; Skin; Skin Physiological Phenomena; Squalene