cis-vaccenic-acid and palmitoleic-acid

The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.

Topics: Culture Media; Diacylglycerol O-Acyltransferase; Fatty Acids, Monounsaturated; Mutation; Oleic Acids; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sterol O-Acyltransferase; Triglycerides

Although previous studies have suggested associations between plasma palmitoleic acid and coronary heart disease (CHD) risk factors, including blood pressure, inflammation, and insulin resistance, little is known about the relation of palmitoleic acid and CHD. This ancillary study of the Physicians' Health Study was designed to examine whether red blood cell (RBC) membrane cis-palmitoleic acid and cis-vaccenic acid-2 fatty acids that can be synthesized endogenously-are associated with CHD risk. We used a risk set sampling method to prospectively select 1,000 incident CHD events and 1,000 matched controls. RBC membrane fatty acids were measured using gas chromatography. The CHD cases were ascertained using an annual follow-up questionnaire and validated by an End Point Committee through a review of the medical records. In a conditional logistic regression analysis adjusting for demographics, anthropometric, lifestyle factors, and co-morbidity, the odds ratios and 95% confidence intervals (CIs) for CHD were 1.0 (referent), 1.29 (95% CI 0.95 to 1.75), 1.08 (95% CI 0.78 to 1.51), 1.25 (95% CI 0.90 to 1.75), and 1.48 (95% CI 1.03 to 2.14) across consecutive quintiles of RBC membrane cis-palmitoleic acid (p for trend = 0.041). The odds ratio associated with each SD higher RBC membrane cis-palmitoleic acid level was 1.19 (95% CI 1.06 to 1.35) in a multivariate-adjusted model. Finally, RBC membrane cis-vaccenic acid was inversely associated with CHD risk (odds ratio 0.79, 95% CI 0.69 to 0.91, per SD increase). In conclusion, our data showed a positive association between RBC membrane cis-palmitoleic acid and CHD risk in male physicians. Furthermore, RBC membrane cis-vaccenic acid was inversely related to CHD.

Topics: Aged; Aged, 80 and over; Case-Control Studies; Coronary Disease; Erythrocyte Membrane; Fatty Acids, Monounsaturated; Follow-Up Studies; Humans; Logistic Models; Male; Middle Aged; Odds Ratio; Oleic Acids; Prospective Studies; Randomized Controlled Trials as Topic; Risk Factors; Surveys and Questionnaires; United States

Our objectives were to: (1) confirm elongation products of palmitoleic acid (16:1 cis-9) elongation in vitro using stable isotopes and (2) evaluate if exogenous supplementation of palmitoleic acid, elongation products, or both are responsible for decreased desaturation and lipogenesis rates observed with palmitoleic acid supplementation in bovine adipocytes. Stromal vascular cultures were isolated from adipose tissue of two beef carcasses, allowed to reach confluence, held for 2 days, and differentiated with a standard hormone cocktail (day 0). On day 2, secondary differentiation media containing 1 of 4 fatty acid treatments [0 μM fatty acid (control), or 150 μM palmitic (16:0), palmitoleic, or cis-vaccenic (18:1 cis-11)] was added for 4 days. On day 6, cells were incubated with [(13)C] 16:1, [(13)C] 2, or [(13)C] 18:0 to estimate elongation, lipogenic, and desaturation rates using gas chromatography-mass spectrometry. Enrichment of [(13)C] 18:1 cis-11 confirmed 18:1 cis-11 is an elongation product of 16:1. Additionally, [(13)C] label was seen in 20:1 cis-13 and cis-9, cis-11 CLA. Synthesis of [(13)C] 16:0 from [(13)C] 2 was reduced (P < 0.05) in palmitoleic acid and cis-vaccenic acid-treated compared with control cells following 36 h incubation. By 12 h of [(13)C] 18:0 incubation, cells supplemented with palmitoleic acid had reduced (P < 0.05) [(13)C] 18:1 cis-9 compared with all other treatments. Gene expression and fatty acid results support isotopic data for lipogenesis and desaturation. Therefore, palmitoleic acid is actively elongated in vitro and its elongation product, cis-vaccenic acid, can also reduce lipogenesis. However, inhibition of desaturation can be directly attributed to palmitoleic acid and not its elongation products, 18:1 cis-11 or 20:1 cis-13.

Topics: Adipocytes; Animals; Cattle; Cells, Cultured; Fatty Acids; Fatty Acids, Monounsaturated; Lipogenesis; Oleic Acids

The relative proportions (% of total fatty acids) of odd-chain (15:0-29:0) and long-chain (22:0-30:0) saturated fatty acids in phospholipids of biotin-deficient rat lymphocytes were significantly increased as compared with biotin-supplemented rats, and the ratio of unsaturated fatty acids to saturated fatty acids in the former was significantly decreased mainly due to the reduced composition of polyunsaturated fatty acids in the omega-3, omega-6, and omega-9 pathway. The ratio of cis-vaccenic acid to palmitoleic acid in biotin-deficient rats was significantly lower than that in control rats, and was thought to be another important, but previously unreported indicator of biotin deficiency. These changes imply that the elongation and desaturation of unsaturated fatty acids are depressed in lymphocytes of biotin-deficient rats, and may contribute to the associated immunological dysfunction in biotin deficiency through abnormal prostaglandin metabolism and/or cell membrane functions.

Topics: Animals; Biotin; Fatty Acids; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Lymphocytes; Male; Oleic Acids; Phospholipids; Rats; Rats, Wistar

Fatty acid synthesis in bacteria and plants is catalysed by a multi-enzyme fatty acid synthetase complex (FAS II) which consists of separate monofunctional polypeptides. Here we present a comparative molecular genetic and biochemical study of the enoyl-ACP reductase FAS components of plant and bacterial origin. The putative bacterial enoyl-ACP reductase gene (envM) was identified on the basis of amino acid sequence similarities with the recently cloned plant enoyl-ACP reductase. Subsequently, it was unambiguously demonstrated by overexpression studies that the envM gene encodes the bacterial enoyl-ACP reductase. An anti-bacterial agent called diazaborine was shown to be a specific inhibitor of the bacterial enoyl-ACP reductase, whereas the plant enzyme was insensitive to this synthetic antibiotic. The close functional relationship between the plant and bacterial enoyl-ACP reductases was inferred from genetic complementation of an envM mutant of Escherichia coli. Ultimately, envM gene-replacement studies, facilitated by the use of diazaborine, demonstrated for the first time that a single component of the plant FAS system can functionally replace its counterpart within the bacterial multienzyme complex. Finally, lipid analysis of recombinant E. coli strains with the hybrid FAS system unexpectedly revealed that enoyl-ACP reductase catalyses a rate-limiting step in the elongation of unsaturated fatty acids.

Topics: Amino Acid Sequence; Base Sequence; Boron Compounds; Brassica; DNA, Recombinant; Enoyl-(Acyl-Carrier-Protein) Reductase (NADH); Escherichia coli; Escherichia coli Proteins; Fatty Acid Synthase, Type II; Fatty Acid Synthases; Fatty Acids; Fatty Acids, Monounsaturated; Genes, Bacterial; Genes, Plant; Models, Biological; Molecular Sequence Data; Oleic Acids; Oxidoreductases; Phospholipids; Recombination, Genetic; Sequence Homology, Amino Acid

The initiation of sporulation in Bacillus subtilis is controlled by the Spo0A transcription factor which is activated by phosphorylation through a phosphorelay mechanism that is dependent upon the activity of one or more protein kinases. The enzymatic activity of one of these protein kinases, KinA, was found to be inhibited in vitro by certain fatty acids. The most potent inhibitors have at least one unsaturated double bond in the cis configuration and a chain length of 16-20 carbon atoms. Homologous isomers with a trans double bond are not inhibitory. Saturated straight- or branched-chain fatty acids are either much weaker inhibitors or have no effect. The inhibitors prevent autophosphorylation of KinA and are non-competitive with ATP. B. subtilis phospholipids were found to contain at least one as yet unidentified type of fatty acid that, when present in an unesterified form, inhibited KinA. The results suggest that the concentration of a specific unsaturated fatty acid may act as a signal linking the initiation of sporulation to the status of membrane synthesis and septation or some other specific membrane-associated activity.

Topics: Bacillus subtilis; Bacterial Proteins; Ethanol; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Isomerism; Oleic Acid; Oleic Acids; Palmitic Acids; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Spores, Bacterial; Structure-Activity Relationship

Weaned rats (21-day old, 44 +/- 2 g) were distributed into 3 groups. The first group was raised on a laboratory diet for 7 or 20 days (control group). The second was fed a diet containing 0.07% fat for 1, 2, 3, 7 or 66 days. The third one was fed the low-fat diet for 7 days and then switched to a laboratory chow diet for 1, 2, 5 or 9 days. Cardiolipin (CL) on the one hand and other mitochondrial phospholipids taken as a whole (PLm) on the other hand were prepared from liver mitochondria and their fatty acids analysed. Polyunsaturated fatty acids in PLm (18:2 (n-6), 20:4 (n-6), 22:6 (n-3) acids) decreased abruptly during the first 3 days of fat deficiency and then remained rather stable till day 7. CL behaved in a quite different way. 18:2 (n-6) acid, the major polyunsaturated fatty acid of CL, decreased continuously between day 1 and day 7 from 79% to 33%. A value of 19.6% was reached on day 66. When deficient rats were transferred to an equilibrated diet, the fatty acid profile of PLm was rapidly restored. Major effects were already achieved during the first 24 h and a fatty acid composition identical to that of control rats was reached within 2 days. A considerably longer period (about 9 days) was necessary for CL to reach a level analogous to that of control rats. The diminution of linoleic acid in CL was brought about by increases in the levels of monoenoic acids: palmitoleic (16:1 (n-7)), oleic (18:1 (n-9)) and cis-vaccenic (18:1 (n-7)) acids which accounted for 18.0%, 17.7% and 17.9% respectively on day 7. Increases in the (n-7) monoenes remained comparatively low in PLm, which showed a sharp rise in their oleic acid content (from 3.9% to 12.7% in 3 days). The proportion of cis-vaccenic acid relative to total octadecenoic acids was decreased from 75% to 50% in CL. A similar trend, but of smaller magnitude, was also noticed in PLm.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Animals; Cardiolipins; Dietary Fats; Fatty Acids; Fatty Acids, Essential; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Linoleic Acid; Linoleic Acids; Male; Mitochondria, Liver; Oleic Acid; Oleic Acids; Palmitic Acids; Phospholipids; Rats; Rats, Inbred Strains