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Sample records for arachidonic acid mobilization

  1. Calcium-dependent phospholipid catabolism and arachidonic acid mobilization in cerebral minces

    SciTech Connect

    Damron, D.S.; Dorman, R.V. )

    1990-06-01

    Cerebral minces were used to investigate the role of calcium influx on trauma-induced alterations of brain lipid metabolism. Cerebral phospholipids, nonpolar lipids, and free fatty acids were radiolabeled in vivo with ({sup 3}H)arachidonic acid. Tissue incubation stimulated the time-dependent catabolism of choline and inositol glycerophospholipids, and resulted in the accumulation of ({sup 3}H)free fatty acids. These effects were attenuated in Ca{sup 2}{sup +}-free incubations, and when EGTA or verapamil were present. The inhibition of calcium influx also reduced the labeling of diglycerides, whereas ethanolamine and serine glycerophospholipids were not affected by incubation or treatments. Replacing Ca{sup 2}{sup +} with other cations also attenuated the incubation-dependent alterations in lipid metabolism. However, only cadmium was able to compete with calcium and reduce the accumulation of ({sup 3}H)free fatty acids. It appeared that about half of the observed phospholipid catabolism was dependent on Ca{sup 2}{sup +} influx and that at least 80% of the ({sup 3}H)free fatty acid accumulation required calcium.

  2. [Studies on arachidonic acid production by Mortierella].

    PubMed

    Bao, S; Zhu, F; Lin, W; Yao, R

    1997-10-01

    The effects of the incubation temperature, initial pH of the medium, carbon source and nitrogen source on the production of arachidonic acid by Mortierella sp. M10 were studied. Thought orthogonal experiments, the optimum culture medium was obtained (g/L): glucose, 100; yeast extract, 10; KNO3, 4.0; KH2PO4, 2.0; CaCl2.2H2O, 0.1; MgSO4.7H2O, 0.5; FeCl3.6H2O, 0.015; ZnSO4.7H2O, 0.0075; CuSO4.5H2O, 0.0005. Under the optimum culture conditions, the dry cell weight and arachidonic acid was 33.51 g/L and 0.827 g/L, respectively. The flask culture process was analysed.

  3. Arachidonic acid and ion channels: an update

    PubMed Central

    Meves, H

    2008-01-01

    Arachidonic acid (AA), a polyunsaturated fatty acid with four double bonds, has multiple actions on living cells. Many of these effects are mediated by an action of AA or its metabolites on ion channels. During the last 10 years, new types of ion channels, transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) channels and non-SOCE channels have been studied. This review summarizes our current knowledge about the effects of AA on TRP and non-SOCE channels as well as classical ion channels. It aims to distinguish between effects of AA itself and effects of AA metabolites. Lipid mediators are of clinical interest because some of them (for example, leukotrienes) play a role in various diseases, others (such as prostaglandins) are targets for pharmacological therapeutic intervention. PMID:18552881

  4. Arachidonic acid metabolism in human prostate cancer

    PubMed Central

    YANG, PEIYING; CARTWRIGHT, CARRIE A.; LI, JIN; WEN, SIJIN; PROKHOROVA, INA N.; SHUREIQI, IMAD; TRONCOSO, PATRICIA; NAVONE, NORA M.; NEWMAN, ROBERT A.; KIM, JERI

    2012-01-01

    The arachidonic acid pathway is important in the development and progression of numerous malignant diseases, including prostate cancer. To more fully evaluate the role of individual cyclooxygenases (COXs), lipoxygenases (LOXs) and their metabolites in prostate cancer, we measured mRNA and protein levels of COXs and LOXs and their arachidonate metabolites in androgen-dependent (LNCaP) and androgen-independent (PC-3 and DU145) prostate cancer cell lines, bone metastasis-derived MDA PCa 2a and MDA PCa 2b cell lines and their corresponding xenograft models, as well as core biopsy specimens of primary prostate cancer and nonneoplastic prostate tissue taken ex vivo after prostatectomy. Relatively high levels of COX-2 mRNA and its product PGE2 were observed only in PC-3 cells and their xenografts. By contrast, levels of the exogenous 12-LOX product 12-HETE were consistently higher in MDA PCa 2b and PC-3 cells and their corresponding xenograft tissues than were those in LNCaP cells. More strikingly, the mean endogenous level of 12-HETE was significantly higher in the primary prostate cancers than in the nonneoplastic prostate tissue (0.094 vs. 0.010 ng/mg protein, respectively; p=0.019). Our results suggest that LOX metabolites such as 12-HETE are critical in prostate cancer progression and that the LOX pathway may be a target for treating and preventing prostate cancer. PMID:22895552

  5. New uses of bioglycerin: production of arachidonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Filamentous fungi of the genus Mortierella are known to produce arachidonic acid from glucose and M. alpina is currently used in industrial scale production of arachidonic acid in Japan. In anticipation of a large excess of co-product bioglycerin from the national biodiesel program, we would like ...

  6. Arachidonic acid inhibits glycine transport in cultured glial cells.

    PubMed Central

    Zafra, F; Alcantara, R; Gomeza, J; Aragon, C; Gimenez, C

    1990-01-01

    The effects of arachidonic acid on glycine uptake, exchange and efflux in C6 glioma cells were investigated. Arachidonic acid produced a dose-dependent inhibition of high-affinity glycine uptake. This effect was not due to a simple detergent-like action on membranes, as the inhibition of glycine transport was most pronounced with cis-unsaturated long-chain fatty acids, whereas saturated and trans-unsaturated fatty acids had relatively little or no effect. Endogenous unsaturated non-esterified fatty acids may exert a similar inhibitory effect on the transport of glycine. The mechanism for this inhibitory effect has been examined in a plasma membrane vesicle preparation derived from C6 cells, which avoids metabolic or compartmentation interferences. The results suggest that part of the selective inhibition of glycine transport by arachidonic acid could be due to the effects of the arachidonic acid on the lipid domain surrounding the carrier. PMID:2121132

  7. Arachidonic acid metabolism in cultured mouse keratinocytes

    SciTech Connect

    Kondoh, H.; Sato, Y.; Kanoh, H.

    1985-07-01

    The authors attempted to characterize the general features of arachidonate metabolism in cultured mouse keratinocytes. The cells labeled with (/sup 3/H)arachidonate were stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), ionophore A23187, and fetal bovine serum (FBS). Common to the three substances, phosphatidylinositol, phosphatidylethanolamine, and phosphatidylcholine almost equally served as sources of arachidonate liberated by the action of phospholipase A2. The stimulation of phospholipase A2 action was observed in the order of A23187 greater than FBS greater than TPA. When stimulated by TPA or A23187, the radioactivity released into the extracellular medium was mostly found in prostaglandin (PG) E2. Formation of other PGs and hydroxyeicosatetraenoate (HETE) was extremely limited. In the case of stimulation by FBS, however, the released radioactivity was mainly associated with non-converted arachidonate. FBS also inhibited the TPA- and A23187-induced conversion of arachidonate to PGE2. Phospholipid degradation induced by the three stimulators was similarly dependent on extracellular Ca/sup 2 +/. The stimulation by FBS and A23187 was suppressed by calmodulin antagonists, though the effect of A23187 was much more sensitive to the antagonists when compared to that of FBS. The authors observed more than additive effects of the three stimulators when tested together.

  8. Decreased plasma arachidonic acid binding capacity in neonates.

    PubMed

    Sadowitz, P D; Walenga, R W; Clark, D; Stuart, M J

    1987-01-01

    Arachidonic acid (AA) metabolites have been implicated in neonatal pathologic states such as respiratory distress syndrome (RDS). Since free (nonprotein bound) AA is the substrate for synthesis of these compounds, a decreased capacity to bind AA in neonatal plasma could contribute to these disorders. AA binding was assayed by equilibrium dialysis in plasma samples from healthy adults and various infant groups. Plasma from these infant groups bound significantly less AA than adult plasma. Premature infants with RDS and premature infants receiving intralipid had the lowest capacity to bind AA. The increased availability of free AA may be important in neonatal pathophysiologic states involving arachidonate metabolites.

  9. Docosahexaenoic acid affects arachidonic acid uptake in megakaryocytes

    SciTech Connect

    Schick, P.K.; Webster, P.

    1987-05-01

    Dietary omega 3 fatty acids are thought to prevent atherosclerosis, possibly by modifying platelet (PT) function and arachidonic acid (20:4) metabolism. The study was designed to determine whether omega 3 fatty acids primarily affect 20:4 metabolism in megakaryocytes (MK), bone marrow precursors of PT, rather than in circulating PT. MK and PT were isolated from guinea pigs and incubated with (/sup 14/C)-20:4 (0.13uM). Docosahexaenoic acid (22:6) is a major omega 3 fatty acid in marine oils. The incubation of MK with 22:6 (0.1, 1.0 uM) resulted in the decrease of incorporation of (/sup 14/C)-20:4 into total MK phospholipids, 16% and 41% respectively. Alpha-linolenic acid (18:3), a major omega 3 fatty acid present in American diets, had no effect on 20:4 uptake in MK. 22:6 primarily affected the uptake of (/sup 14/C)-20:4 into phosphatidylethanolamine (PE) and phosphatidylserine (PS) in MK. In MK, 22:6 (0.1, 1.0 uM) caused a decrease of incorporation of (/sup 14/C)-20:4 into PE, 21% and 55% respectively; a decrease into PS, 16% and 48% respectively; but only a decrease of 4% and 18%, respectively, into phosphatidylcholine; and a decrease of 3% and 21% into phosphatidylinositol 22:6 (3.0 uM) had no effect on the uptake of AA into PT phospholipids. The study shows that 22:6 has a selective effect on AA uptake in MK and that the acylation or transacylation of PE and PS are primarily affected. 22:6 and other marine omega 3 fatty acids appear to primarily affect megakaryocytes which may result in the production of platelets with abnormal content and compartmentalization of AA.

  10. The essentiality of arachidonic acid and docosahexaenoic acid

    PubMed Central

    Le, Hau D.; Meisel, Jonathan A.; de Meijer, Vincent E.; Gura, Kathleen M.; Puder, Mark

    2012-01-01

    Objective The purpose of this review is to correlate the clinical finding that patients receiving parenteral nutrition with a fish oil-based lipid emulsion do not develop essential fatty acid deficiency (EFAD) with an experimental murine model, thus showing that arachidonic acid (AA) and docosahexaenoic acid (DHA) are likely to be the essential fatty acids. Background Conventional belief is that linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3) are the essential fatty acids (EFAs). We have shown that a fish oil-based lipid emulsion containing AA (omega-6) and docosahexaenoic acid (DHA, omega-3) and insignificant quantities of LA and ALA is efficacious in the treatment of parenteral nutrition-associated liver disease (PNALD), a major cause of liver-related morbidity and mortality. The prospect of using a fish oil-based lipid emulsion as monotherapy has raised concerns of EFAD development, hindering its adoption into clinical practice. Design Data from patients in our institution who received PN with a fish oil-based lipid emulsion was reviewed for clinical and biochemical evidence of EFAD, defined as an elevated triene-tetraene ratio (Mead acid/AA >0.2). We also investigated the minimum amount of fish oil required to prevent EFAD in a murine model and determined whether DHA and AA alone can prevent EFAD. Results No patients receiving PN with a fish oil-based lipid emulsion in our institution have developed biochemical or clinical evidence of EFAD such as an elevated triene-tetraene ratio, growth retardation or dermatitis. This observation parallels our previously published animal studies, which demonstrated prevention of EFAD when thirteen percent of total calories were from fish oil. Moreover, current work in our laboratory shows that AA and DHA provision alone is sufficient to prevent biochemical and physiologic evidence of EFAD in a murine model. Conclusions When dosed appropriately, fish oil-based lipid emulsions contain sufficient EFAs to

  11. Arachidonic acid enhances turnover of the dermal skeleton: studies on zebrafish scales.

    PubMed

    de Vrieze, Erik; Moren, Mari; Metz, Juriaan R; Flik, Gert; Lie, Kai Kristoffer

    2014-01-01

    In fish nutrition, the ratio between omega-3 and omega-6 poly-unsaturated fatty acids influences skeletal development. Supplementation of fish oils with vegetable oils increases the content of omega-6 fatty acids, such as arachidonic acid in the diet. Arachidonic acid is metabolized by cyclooxygenases to prostaglandin E2, an eicosanoid with effects on bone formation and remodeling. To elucidate effects of poly-unsaturated fatty acids on developing and existing skeletal tissues, zebrafish (Danio rerio) were fed (micro-) diets low and high in arachidonic acid content. Elasmoid scales, dermal skeletal plates, are ideal to study skeletal metabolism in zebrafish and were exploited in the present study. The fatty acid profile resulting from a high arachidonic acid diet induced mild but significant increase in matrix resorption in ontogenetic scales of adult zebrafish. Arachidonic acid affected scale regeneration (following removal of ontogenetic scales): mineral deposition was altered and both gene expression and enzymatic matrix metalloproteinase activity changed towards enhanced osteoclastic activity. Arachidonic acid also clearly stimulates matrix metalloproteinase activity in vitro, which implies that resorptive effects of arachidonic acid are mediated by matrix metalloproteinases. The gene expression profile further suggests that arachidonic acid increases maturation rate of the regenerating scale; in other words, enhances turnover. The zebrafish scale is an excellent model to study how and which fatty acids affect skeletal formation.

  12. Arachidonic acid enhances reproduction in Daphnia magna and mitigates changes in sex ratios induced by pyriproxyfen.

    PubMed

    Ginjupalli, Gautam K; Gerard, Patrick D; Baldwin, William S

    2015-03-01

    Arachidonic acid is 1 of only 2 unsaturated fatty acids retained in the ovaries of crustaceans and an inhibitor of HR97g, a nuclear receptor expressed in adult ovaries. The authors hypothesized that, as a key fatty acid, arachidonic acid may be associated with reproduction and potentially environmental sex determination in Daphnia. Reproduction assays with arachidonic acid indicate that it alters female:male sex ratios by increasing female production. This reproductive effect only occurred during a restricted Pseudokirchneriella subcapitata diet. Next, the authors tested whether enriching a poorer algal diet (Chlorella vulgaris) with arachidonic acid enhances overall reproduction and sex ratios. Arachidonic acid enrichment of a C. vulgaris diet also enhances fecundity at 1.0 µM and 4.0 µM by 30% to 40% in the presence and absence of pyriproxyfen. This indicates that arachidonic acid is crucial in reproduction regardless of environmental sex determination. Furthermore, the data indicate that P. subcapitata may provide a threshold concentration of arachidonic acid needed for reproduction. Diet-switch experiments from P. subcapitata to C. vulgaris mitigate some, but not all, of arachidonic acid's effects when compared with a C. vulgaris-only diet, suggesting that some arachidonic acid provided by P. subcapitata is retained. In summary, arachidonic acid supplementation increases reproduction and represses pyriproxyfen-induced environmental sex determination in D. magna in restricted diets. A diet rich in arachidonic acid may provide protection from some reproductive toxicants such as the juvenile hormone agonist pyriproxyfen. Environ Toxicol Chem 2015;34:527-535. © 2014 SETAC.

  13. Altered arachidonic acid metabolism and platelet size in atopic subjects

    SciTech Connect

    Audera, C.; Rocklin, R.; Vaillancourt, R.; Jakubowski, J.A.; Deykin, D.

    1988-03-01

    The release and metabolism of endogenous arachidonic acid (AA) in physiologically activated platelets obtained from 11 atopic patients with allergic rhinitis and/or asthma was compared to that of sex- and age-matched nonatopic controls. Prelabeled (/sup 3/H)AA platelets were stimulated with thrombin or collagen and the amount of free (/sup 3/H)AA and radiolabeled metabolites released were measured by high-performance liquid chromatography. The results obtained indicate that although the incorporation of (/sup 3/H)AA into platelet phospholipids and total release of /sup 3/H-radioactivity upon stimulation were comparable in the two groups, the percentage of /sup 3/H-radioactivity released from platelets as free AA was significantly lower (P less than 0.01) in the atopic group. The reduction in free (/sup 3/H)AA was accompanied by an increase (P less than 0.01) in the percentage of /sup 3/H-radioactivity released as cyclooxygenase products in atopic platelets (compared to nonatopic cells) after stimulation with 10 and 25 micrograms/ml collagen. The amount of platelet lipoxygenase product released was comparable between the two groups. Although the blood platelet counts were similar, the mean platelet volume was statistically higher (P less than 0.01) in the atopic group. These results indicate that arachidonic acid metabolism in atopic platelets is altered, the pathophysiological significance of which remains to be clarified.

  14. Human monocyte differentiation stage affects response to arachidonic acid.

    PubMed

    Escobar-Alvarez, Elizabeth; Pelaez, Carlos A; García, Luis F; Rojas, Mauricio

    2010-01-01

    AA-induced cell death mechanisms acting on human monocytes and monocyte-derived macrophages (MDM), U937 promonocytes and PMA-differentiated U937 cells were studied. Arachidonic acid induced apoptosis and necrosis in monocytes and U937 cells but only apoptosis in MDM and U937D cells. AA increased both types of death in Mycobacterium tuberculosis-infected cells and increased the percentage of TNFalpha+ cells and reduced IL-10+ cells. Experiments blocking these cytokines indicated that AA-mediated death was TNFalpha- and IL-10-independent. The differences in AA-mediated cell death could be explained by high ROS, calpain and sPLA-2 production and activity in monocytes. Blocking sPLA-2 in monocytes and treatment with antioxidants favored M. tuberculosis control whereas AA enhanced M. tuberculosis growth in MDM. Such evidence suggested that AA-modulated effector mechanisms depend on mononuclear phagocytes' differentiation stage.

  15. Arachidonic acid stimulates glucose uptake in cerebral cortical astrocytes.

    PubMed Central

    Yu, N; Martin, J L; Stella, N; Magistretti, P J

    1993-01-01

    Arachidonic acid (AA) has recently been shown to influence various cellular functions in the central nervous system. Here we report that AA increases, in a time- and concentration-dependent manner, 2-deoxy-D-[1-3H]glucose ([3H]2DG) uptake in primary cultures of astrocytes prepared from the cerebral cortex of neonatal mice. This effect is mimicked by an unsaturated fatty acid such as linolenic acid, while palmitic and arachidic acids, two saturated fatty acids, are inactive. Pharmacological agents that increase the endogenous levels of AA by stimulating AA release (melittin) or by inhibiting its reacylation (thimerosal) also promote [3H]2DG uptake by astrocytes. We also report that norepinephrine (NE) stimulates the release of [3H]AA from membrane phospholipids, with an EC50 of 3 microM; this effect is accompanied, with a temporal delay of approximately 4 min, by the stimulation of [3H]2DG uptake, for which the EC50 of NE is 1 microM. Since the cerebral cortex, the brain region from which astrocytes used in this study were prepared, receives a massive noradrenergic innervation, originating from the locus coeruleus, the effects of NE reported here further stress the notion that certain neurotransmitters may play a role in the regulation of energy metabolism in the cerebral cortex and point at astrocytes as the likely targets of such metabolic effects. PMID:8483920

  16. Source of the arachidonic acid released on stimulation of rat basophilic leukemia cells

    SciTech Connect

    Garcia-Gil, M.; Siraganian, R.P.

    1986-05-15

    Triggering of rat basophilic leukemia cells for histamine secretion is accompanied by arachidonic acid release. The source of this arachidonic acid released after IgE or calcium ionophore A23187 stimulation was studied. The 48-hr culture of the cells with (/sup 14/C)arachidonic acid resulted in labeling of the phospholipids to constant specific activity. After IgE stimulation, 8.8% of the cellular (/sup 14/C)arachidonate was released; this was predominantly from phosphatidylinositol (PI)/phosphatidylserine (PS) (66.3%), less from phosphatidylethanolamine (PE) (25.9%), and minimally from phosphatidylcholine (PC). In contrast, after ionophore stimulation the cells released 16.4% of cellular (/sup 14/C)arachidonate, most of this was from PE (55.4%) followed by about equal amounts from PS/PI and PC (24% and 20%, respectively). Therefore, the source of the released arachidonic acid depends on the stimulus. In contrast, the results are different when the cells are cultured for only 2 hr with (/sup 14/C)arachidonic acid. The label in phospholipids was in PC (44%), PE (38%), and PI/PS (20%); the stimulation of the cells with IgE or ionophore resulted in the release of the (/sup 14/C)arachidonate from PC (81% and 96%, respectively). This suggests the presence of several pools of phospholipids that are labeled at different rates and have variable proximity and/or accessibility to the phospholipase(s) enzyme(s) activated during cell secretion.

  17. The influence of mono- and divalent cations on the cardiac metabolism of arachidonic acid

    SciTech Connect

    Weis, M.T.; Malik, K.U. )

    1989-06-01

    Our previous study indicated that, in the isolated rabbit heart, perfusion with Ca2+ free Krebs Henseleit buffer (KHB) results in increased conversion of exogenous arachidonic acid to PGE2 and 6-keto-PGF1 alpha, probably as the result of increased availability of substrate to cyclooxygenase. Since perfusion with Ca2+ free buffer is known to cause alterations in the cardiac content of various mono- and divalent cations, the present study was performed to determine: (a) The relationship between the conversion of exogenous arachidonic acid to prostaglandins and cardiac content of Na+, K+, Ca2+ and Mg2+; and (b) Whether enhanced arachidonic acid conversion to prostaglandins during Ca2+ free perfusion is due to reduced incorporation of this fatty acid into tissue lipids. Perfusion of the rabbit heart with Ca2+ free buffer produced a significant reduction in the tissue content of Na+, K+, Ca2+ and Mg2+. However, the production of 6-keto-PGF1 alpha from exogenous arachidonic acid was linearly correlated with tissue Mg2+. These observations, together with our finding that perfusion with Ca2+ free KHB reduced the incorporation of (3H) arachidonic acid into tissue lipids, suggests that Ca2+ free perfusion may, by reducing the activity of arachidonyl CoA synthetase (a Mg2+ dependent enzyme), decrease the acylation of arachidonic acid into lipids, thus increasing the availability of arachidonic acid to cyclooxygenase.

  18. Dietary arachidonic acid in perinatal nutrition: a commentary.

    PubMed

    Lauritzen, Lotte; Fewtrell, Mary; Agostoni, Carlo

    2015-01-01

    Arachidonic acid (AA) is supplied together with docosahexaenoic acid (DHA) in infant formulas, but we have limited knowledge about the effects of supplementation with either of these long-chain polyunsaturated fatty acids (LCPUFA) on growth and developmental outcomes. AA is present in similar levels in breast milk throughout the world, whereas the level of DHA is highly diet dependent. Autopsy studies show similar diet-dependent variation in brain DHA, whereas AA is little affected by intake. Early intake of DHA has been shown to affect visual development, but the effect of LCPUFA on neurodevelopment remains to be established. Few studies have found any functional difference between infants supplemented with DHA alone compared to DHA+AA, but some studies show neurodevelopmental advantages in breast-fed infants of mothers supplemented with n-3 LCPUFA alone. It also remains to be established whether the AA/DHA balance could affect allergic and inflammatory outcomes later in life. Disentangling effects of genetic variability and dietary intake on AA and DHA-status and on functional outcomes may be an important step in the process of determining whether AA-intake is of any physiological or clinical importance. However, based on the current evidence we hypothesize that dietary AA plays a minor role on growth and development relative to the impact of dietary DHA.

  19. The Essentiality of Arachidonic Acid in Infant Development.

    PubMed

    Hadley, Kevin B; Ryan, Alan S; Forsyth, Stewart; Gautier, Sheila; Salem, Norman

    2016-04-12

    Arachidonic acid (ARA, 20:4n-6) is an n-6 polyunsaturated 20-carbon fatty acid formed by the biosynthesis from linoleic acid (LA, 18:2n-6). This review considers the essential role that ARA plays in infant development. ARA is always present in human milk at a relatively fixed level and is accumulated in tissues throughout the body where it serves several important functions. Without the provision of preformed ARA in human milk or infant formula the growing infant cannot maintain ARA levels from synthetic pathways alone that are sufficient to meet metabolic demand. During late infancy and early childhood the amount of dietary ARA provided by solid foods is low. ARA serves as a precursor to leukotrienes, prostaglandins, and thromboxanes, collectively known as eicosanoids which are important for immunity and immune response. There is strong evidence based on animal and human studies that ARA is critical for infant growth, brain development, and health. These studies also demonstrate the importance of balancing the amounts of ARA and DHA as too much DHA may suppress the benefits provided by ARA. Both ARA and DHA have been added to infant formulas and follow-on formulas for more than two decades. The amounts and ratios of ARA and DHA needed in infant formula are discussed based on an in depth review of the available scientific evidence.

  20. The Essentiality of Arachidonic Acid in Infant Development

    PubMed Central

    Hadley, Kevin B.; Ryan, Alan S.; Forsyth, Stewart; Gautier, Sheila; Salem, Norman

    2016-01-01

    Arachidonic acid (ARA, 20:4n-6) is an n-6 polyunsaturated 20-carbon fatty acid formed by the biosynthesis from linoleic acid (LA, 18:2n-6). This review considers the essential role that ARA plays in infant development. ARA is always present in human milk at a relatively fixed level and is accumulated in tissues throughout the body where it serves several important functions. Without the provision of preformed ARA in human milk or infant formula the growing infant cannot maintain ARA levels from synthetic pathways alone that are sufficient to meet metabolic demand. During late infancy and early childhood the amount of dietary ARA provided by solid foods is low. ARA serves as a precursor to leukotrienes, prostaglandins, and thromboxanes, collectively known as eicosanoids which are important for immunity and immune response. There is strong evidence based on animal and human studies that ARA is critical for infant growth, brain development, and health. These studies also demonstrate the importance of balancing the amounts of ARA and DHA as too much DHA may suppress the benefits provided by ARA. Both ARA and DHA have been added to infant formulas and follow-on formulas for more than two decades. The amounts and ratios of ARA and DHA needed in infant formula are discussed based on an in depth review of the available scientific evidence. PMID:27077882

  1. Arachidonic acid metabolism in glutathione-deficient macrophages.

    PubMed Central

    Rouzer, C A; Scott, W A; Griffith, O W; Hamill, A L; Cohn, Z A

    1982-01-01

    Mouse resident peritoneal macrophages were treated with the glutathione (GSH) synthesis inhibitor buthionine sulfoximine to deplete intracellular GSH. The arachidonic acid metabolites released by the GSH-depleted macrophages in response to a zymosan challenge were analyzed by HPLC. Buthionine sulfoximine treatment resulted in inhibition of both prostaglandin E2 and leukotriene C synthesis that was directly related to the degree of GSH depletion. Macrophages in which GSH levels were reduced to 3% of normal exhibited reductions to 4% and 1%, respectively, in PGE2 and LTC formation. The total quantity of cyclooxygenase metabolites secreted by GSH-deficient macrophages was identical to that of control cells as a result of increased synthesis of prostacyclin and, to a lesser extent, 12-L-hydroxy-5,8,10-heptadecatrienoic acid. Total lipoxygenase products were decreased, however; increased formation of hydroxyicosatetraenoic acids only partially compensated for the deficit in leukotriene C production. These findings extent our earlier observations on the inhibition of leukotriene C synthesis in GSH-depleted macrophages and confirm with intact cells the previously suggested role of GSH in prostaglandin E2 formation. PMID:6803245

  2. Synaptic plasticity preserved with arachidonic acid diet in aged rats.

    PubMed

    Kotani, Susumu; Nakazawa, Hiroe; Tokimasa, Takayuki; Akimoto, Kengo; Kawashima, Hiroshi; Toyoda-Ono, Yoshiko; Kiso, Yoshinobu; Okaichi, Hiroshige; Sakakibara, Manabu

    2003-08-01

    We examined whether synaptic plasticity was preserved in aged rats administered an arachidonic acid (AA) containing diet. Young male Fischer-344 rats (2 mo of age), and two groups of aged rats of the same strain (2 y of age) who consumed either a control diet or an AA ethyl ester-containing diet for at least 3 mo were used. In the Morris water maze task, aged rats on the AA diet had tendency to show better performance than aged rats on the control diet. Long-term potentiation induced by tetanic stimulation was recorded from a 300 microm thick hippocampal slice with a 36 multi-electrode-array positioned at the dendrites of CA1 pyramidal neurons. The degree of potentiation after 1 h in aged rats on the AA diet was comparable as that of young controls. Phospholipid analysis revealed that AA and docosahexaenoic acid were the major fatty acids in the hippocampus in aged rats. There was a correlation between the behavioral measure and the changes in excitatory postsynaptic potential slope and between the physiologic measure and the total amount of AA in hippocampus.

  3. The rabbit pulmonary cytochrome P450 arachidonic acid metabolic pathway: characterization and significance.

    PubMed Central

    Zeldin, D C; Plitman, J D; Kobayashi, J; Miller, R F; Snapper, J R; Falck, J R; Szarek, J L; Philpot, R M; Capdevila, J H

    1995-01-01

    Cytochrome P450 metabolizes arachidonic acid to several unique and biologically active compounds in rabbit liver and kidney. Microsomal fractions prepared from rabbit lung homogenates metabolized arachidonic acid through cytochrome P450 pathways, yielding cis-epoxyeicosatrienoic acids (EETs) and their hydration products, vic-dihydroxyeicosatrienoic acids, mid-chain cis-trans conjugated dienols, and 19- and 20-hydroxyeicosatetraenoic acids. Inhibition studies using polyclonal antibodies prepared against purified CYP2B4 demonstrated 100% inhibition of arachidonic acid epoxide formation. Purified CYP2B4, reconstituted in the presence of NADPH-cytochrome P450 reductase and cytochrome b5, metabolized arachidonic acid, producing primarily EETs. EETs were detected in lung homogenate using gas chromatography/mass spectroscopy, providing evidence for the in vivo pulmonary cytochrome P450 epoxidation of arachidonic acid. Chiral analysis of these lung EETs demonstrated a preference for the 14(R),15(S)-, 11(S),12(R)-, and 8(S),9(R)-EET enantiomers. Both EETs and vic-dihydroxyeicosatrienoic acids were detected in bronchoalveolar lavage fluid. At micromolar concentrations, methylated 5,6-EET and 8,9-EET significantly relaxed histamine-contracted guinea pig hilar bronchi in vitro. In contrast, 20-hydroxyeicosatetraenoic acid caused contraction to near maximal tension. We conclude that CYP2B4, an abundant rabbit lung cytochrome P450 enzyme, is the primary constitutive pulmonary arachidonic acid epoxygenase and that these locally produced, biologically active eicosanoids may be involved in maintaining homeostasis within the lung. Images PMID:7738183

  4. Action of luteinizing hormone-releasing hormone: involvement of novel arachidonic acid metabolites.

    PubMed Central

    Snyder, G D; Capdevila, J; Chacos, N; Manna, S; Falck, J R

    1983-01-01

    Anterior pituitary cells were incubated in the presence of luteinizing hormone-releasing hormone and one of three inhibitors of arachidonic acid metabolism:indomethacin, an inhibitor of the cyclooxygenase system; nordihydroguaiaretic acid, an antioxidant that inhibits lipoxygenase; and icosatetraynoic acid, an acetylenic analogue of arachidonic acid that blocks all known pathways of arachidonic acid metabolism. Indomethacin was ineffective in blocking luteinizing hormone-releasing hormone-stimulated luteinizing hormone secretion. Nordihydroguaiaretic acid was only marginally capable of inhibiting luteinizing hormone-releasing hormone-stimulated luteinizing hormone secretion. Icosatetraynoic acid at 10 microM completely inhibited stimulated luteinizing hormone secretion. Addition of several epoxygenated arachidonic acid metabolites to cells in vitro resulted in secretion of luteinizing hormone equal to or greater than that induced by 10 nM luteinizing hormone-releasing hormone. The half-maximal effective dose for these compounds was approximately 50 nM. The 5,6-epoxyicosatrienoic acid was the most potent of the compounds tested. These studies suggest that luteinizing hormone-releasing hormone-stimulated luteinizing hormone release is closely coupled with the production of oxidized arachidonic acid metabolites. Moreover, one or more of the epoxygenated arachidonic acid metabolites might be a component of the cascade of reactions initiated by luteinizing hormone-releasing hormone that ultimately results in secretion of luteinizing hormone. PMID:6344087

  5. Mood-Stabilizers Target the Brain Arachidonic Acid Cascade

    PubMed Central

    Rao, Jagadeesh S.; Rapoport, Stanley I.

    2009-01-01

    Bipolar disorder (BD) is a severe psychiatric illness characterized by recurrent manic and depressive episodes, without a characteristic neuropathology or clear etiology. Drugs effective in BD target many key signaling pathways in animal and cell studies. However, their mode of action in the BD brain remains elusive. In the rat brain, some of the mood stabilizers effective in treating mania (lithium, carbamazepine, valproate) or depression (lamotrigine) in BD are reported to decrease transcription of cytosolic phospholipase A2 and cyclooxygenase-2 and to reduce levels of AP-2 and NF-κB, transcription factors of the two enzymes. The anti-manic drugs also decrease arachidonic acid (AA) turnover in brain phospholipids when given chronically to rats. Thus, drugs effective in BD commonly target AA cascade kinetics as well as AA cascade enzymes and their transcription factors in the rat brain. These studies suggest that BD is associated with increased AA signaling in the brain. Developing therapeutic agents that suppress brain AA signaling could lead to additional treatments for BD. In this review, we discuss the mechanisms of action of mood stabilizers and the effects of docosahexaenoic acid on AA cascade enzymes in relation to BD. PMID:20021459

  6. Is the brain arachidonic acid cascade a common target of drugs used to manage bipolar disorder?

    PubMed

    Bazinet, Richard P

    2009-10-01

    Although lithium has been used therapeutically to treat patients with bipolar disorder for over 50 years, its mechanism of action, as well as that of other drugs used to treat bipolar disorder, is not agreed upon. In the present paper, I review studies in unanaesthetized rats using a neuropharmacological approach, combined with kinetic, biochemical and molecular biology techniques, demonstrating that chronic administration of three commonly used mood stabilizers (lithium, valproic acid and carbamazepine), at therapeutically relevant doses, selectively target the brain arachidonic acid cascade. Upon chronic administration, lithium and carbamazepine decrease the binding activity of activator protein-2 and, in turn, the transcription, translation and activity of its arachidonic acid-selective calcium-dependent phospholipase A(2) gene product, whereas chronic valproic acid non-competitively inhibits long-chain acyl-CoA synthetase. The net overlapping effects of the three mood stabilizers are decreased turnover of arachidonic acid, but not of docosahexaenoic acid, in rat brain phospholipids, as well as decreased brain cyclo-oxygenase-2 and prostaglandin E(2). As an extension of this theory, drugs that are thought to induce switching to mania, especially when administered during bipolar depression (fluoxetine and imipramine), up-regulate enzymes of the arachidonic acid cascade and turnover of arachidonic acid in rat brain phospholipids. Future basic and clinical studies on the arachidonic acid hypothesis of bipolar disorder are warranted.

  7. Ancestral genetic complexity of arachidonic acid metabolism in Metazoa.

    PubMed

    Yuan, Dongjuan; Zou, Qiuqiong; Yu, Ting; Song, Cuikai; Huang, Shengfeng; Chen, Shangwu; Ren, Zhenghua; Xu, Anlong

    2014-09-01

    Eicosanoids play an important role in inducing complex and crucial physiological processes in animals. Eicosanoid biosynthesis in animals is widely reported; however, eicosanoid production in invertebrate tissue is remarkably different to vertebrates and in certain respects remains elusive. We, for the first time, compared the orthologs involved in arachidonic acid (AA) metabolism in 14 species of invertebrates and 3 species of vertebrates. Based on parsimony, a complex AA-metabolic system may have existed in the common ancestor of the Metazoa, and then expanded and diversified through invertebrate lineages. A primary vertebrate-like AA-metabolic system via cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) pathways was further identified in the basal chordate, amphioxus. The expression profiling of AA-metabolic enzymes and lipidomic analysis of eicosanoid production in the tissues of amphioxus supported our supposition. Thus, we proposed that the ancestral complexity of AA-metabolic network diversified with the different lineages of invertebrates, adapting with the diversity of body plans and ecological opportunity, and arriving at the vertebrate-like pattern in the basal chordate, amphioxus.

  8. Cytochrome P450 arachidonic acid metabolism in bovine corneal epithelium

    SciTech Connect

    Masferrer, J.; Schwartzman, M.L.; Abraham, N.G.; Dunn, M.W.; McGiff, J.C.

    1986-03-01

    The presence of the cytochrom P450 system and its involvement in the metabolism of AA was studied in the corneal epithelium. This tissue contains cytochrome P450 as assessed directly by measurement of the carbon monoxide reduced spectrum (specific activity of 161 pmol/10 mg protein) and indirectly by measuring the activity of aryl hydrocarbon hydroxylase (AHH) - a cytochrome P450-dependent enzyme (11-39 pmol 3-OH benzopyrene/mg protein/10 min). When corneal epithelial microsomes were incubated with /sup 14/C-arachidonic acid, 30-50% of the total radioactivity was converted to two peaks, I and II. Further separation using high performance liquid chromatography has shown that each peak contains two metabolites, A,B and C,D. Metabolite formation was dependent on the addition of NADPH (1 mM) and inhibited by carbon monoxide and SKF-525A (100 ..mu..M) suggesting a cytochrome P450-dependent mechanism. Compound C (5-10 ..mu..M) inhibited the activity of corneal epithelial Na-K-ATPase by 30-60%, being 100-fold more potent than ouabain. Compound D (10-100 ng) induced a dose dependent relaxation of the rat caudal artery. Compound D also inhibited corneal Na-K-ATPase activity but less potently than compound C. These compounds may be important to transport processes of ocular epithelia and participate in the control of the ocular circulation and aqueous humor dynamics.

  9. Actions of arachidonic acid on erythrocyte membrane Rb permeability.

    PubMed

    Dwight, J F; Hendry, B M

    1995-07-14

    The effects of non-esterified arachidonic acid (AA) on erythrocyte membrane ion permeability have been studied using 86Rb flux measurements. [14C]AA was used to quantify membrane incorporation of AA and to show AA removal by albumin washing. The actions of vitamin E and other antioxidants on the effects of AA were examined. Reversible membrane incorporation of 700-2000 nmol AA per ml cells was achieved without significant haemolysis or morphological change. AA incorporation caused a reversible mean increase in bumetanide-sensitive Rb influx of 34% (S.E.M. 4.5, n = 23). This action could be partially prevented by co-incubation with vitamin E, but not by Trolox or dithioerythritol. AA incorporation caused an irreversible mean increase in residual Rb permeability (bumetanide and ouabain insensitive) of 130% (S.E.M. 22, n = 20), associated with a rise in intracellular Na and a fall in intracellular K concentrations. This action was also partially prevented by co-incubation with vitamin E. The effects of AA incorporation on Na,K-ATPase function were difficult to quantify because of the concomitant rises in intracellular Na but the data are consistent with approximately 20% inhibition of activity. Modulation of membrane ion permeability by AA appears to be partially mediated by lipid peroxidation and may have pathophysiological significance.

  10. Dietary arachidonic acid as a risk factor for age-associated neurodegenerative diseases: Potential mechanisms.

    PubMed

    Thomas, Mélanie H; Pelleieux, Sandra; Vitale, Nicolas; Olivier, Jean Luc

    2016-11-01

    Alzheimer's disease and associated diseases constitute a major public health concern worldwide. Nutrition-based, preventive strategies could possibly be effective in delaying the occurrence of these diseases and lower their prevalence. Arachidonic acid is the second major polyunsaturated fatty acid (PUFA) and several studies support its involvement in Alzheimer's disease. The objective of this review is to examine how dietary arachidonic acid contributes to Alzheimer's disease mechanisms and therefore to its prevention. First, we explore the sources of neuronal arachidonic acid that could potentially originate from either the conversion of linoleic acid, or from dietary sources and transfer across the blood-brain-barrier. In a second part, a brief overview of the role of the two main agents of Alzheimer's disease, tau protein and Aβ peptide is given, followed by the examination of the relationship between arachidonic acid and the disease. Third, the putative mechanisms by which arachidonic acid could influence Alzheimer's disease occurrence and evolution are presented. The conclusion is devoted to what remains to be determined before integrating arachidonic acid in the design of preventive strategies against Alzheimer's disease and other neurodegenerative diseases.

  11. Enhancement of arachidonic acid signaling pathway by nicotinic acid receptor HM74A.

    PubMed

    Tang, Yuting; Zhou, Lubing; Gunnet, Joseph W; Wines, Pamela G; Cryan, Ellen V; Demarest, Keith T

    2006-06-23

    HM74A is a G protein-coupled receptor for nicotinic acid (niacin), which has been used clinically to treat dyslipidemia for decades. The molecular mechanisms whereby niacin exerts its pleiotropic effects on lipid metabolism remain largely unknown. In addition, the most common side effect in niacin therapy is skin flushing that is caused by prostaglandin release, suggesting that the phospholipase A(2) (PLA(2))/arachidonic acid (AA) pathway is involved. Various eicosanoids have been shown to activate peroxisome-proliferator activated receptors (PPAR) that play a diverse array of roles in lipid metabolism. To further elucidate the potential roles of HM74A in mediating the therapeutic effects and/or side effects of niacin, we sought to explore the signaling events upon HM74A activation. Here we demonstrated that HM74A synergistically enhanced UTP- and bradykinin-mediated AA release in a pertussis toxin-sensitive manner in A431 cells. Activation of HM74A also led to Ca(2+)-mobilization and enhanced bradykinin-promoted Ca(2+)-mobilization through Gi protein. While HM74A increased ERK1/2 activation by the bradykinin receptor, it had no effects on UTP-promoted ERK1/2 activation.Furthermore, UTP- and bradykinin-mediated AA release was significantly decreased in the presence of both MAPK kinase inhibitor PD 098059 and PKC inhibitor GF 109203X. However, the synergistic effects of HM74A were not dramatically affected by co-treatment with both inhibitors, indicating the cross-talk occurred at the receptor level. Finally, stimulation of A431 cells transiently transfected with PPRE-luciferase with AA significantly induced luciferase activity, mimicking the effects of PPARgamma agonist rosiglitazone, suggesting that alteration of AA signaling pathway can regulate gene expression via endogenous PPARs.

  12. Enhancement of arachidonic acid signaling pathway by nicotinic acid receptor HM74A

    SciTech Connect

    Tang, Yuting . E-mail: ytang@prdus.jnj.com; Zhou, Lubing; Gunnet, Joseph W.; Wines, Pamela G.; Cryan, Ellen V.; Demarest, Keith T.

    2006-06-23

    HM74A is a G protein-coupled receptor for nicotinic acid (niacin), which has been used clinically to treat dyslipidemia for decades. The molecular mechanisms whereby niacin exerts its pleiotropic effects on lipid metabolism remain largely unknown. In addition, the most common side effect in niacin therapy is skin flushing that is caused by prostaglandin release, suggesting that the phospholipase A{sub 2} (PLA{sub 2})/arachidonic acid (AA) pathway is involved. Various eicosanoids have been shown to activate peroxisome-proliferator activated receptors (PPAR) that play a diverse array of roles in lipid metabolism. To further elucidate the potential roles of HM74A in mediating the therapeutic effects and/or side effects of niacin, we sought to explore the signaling events upon HM74A activation. Here we demonstrated that HM74A synergistically enhanced UTP- and bradykinin-mediated AA release in a pertussis toxin-sensitive manner in A431 cells. Activation of HM74A also led to Ca{sup 2+}-mobilization and enhanced bradykinin-promoted Ca{sup 2+}-mobilization through Gi protein. While HM74A increased ERK1/2 activation by the bradykinin receptor, it had no effects on UTP-promoted ERK1/2 activation.Furthermore, UTP- and bradykinin-mediated AA release was significantly decreased in the presence of both MAPK kinase inhibitor PD 098059 and PKC inhibitor GF 109203X. However, the synergistic effects of HM74A were not dramatically affected by co-treatment with both inhibitors, indicating the cross-talk occurred at the receptor level. Finally, stimulation of A431 cells transiently transfected with PPRE-luciferase with AA significantly induced luciferase activity, mimicking the effects of PPAR{gamma} agonist rosiglitazone, suggesting that alteration of AA signaling pathway can regulate gene expression via endogenous PPARs.

  13. Role of Arachidonic Acid in Promoting Hair Growth

    PubMed Central

    Munkhbayar, Semchin; Jang, Sunhyae; Cho, A-Ri; Choi, Soon-Jin; Shin, Chang Yup; Eun, Hee Chul; Kim, Kyu Han

    2016-01-01

    Background Arachidonic acid (AA) is an omega-6 polyunsaturated fatty acid present in all mammalian cell membranes, and involved in the regulation of many cellular processes, including cell survival, angiogenesis, and mitogenesis. The dermal papilla, composed of specialized fibroblasts located in the bulb of the hair follicle, contributes to the control of hair growth and the hair cycle. Objective This study investigated the effect of AA on hair growth by using in vivo and in vitro models. Methods The effect of AA on human dermal papilla cells (hDPCs) and hair shaft elongation was evaluated by MTT assay and hair follicle organ culture, respectively. The expression of various growth and survival factors in hDPCs were investigated by western blot or immunohistochemistry. The ability of AA to induce and prolong anagen phase in C57BL/6 mice was analyzed. Results AA was found to enhance the viability of hDPCs and promote the expression of several factors responsible for hair growth, including fibroblast growth factor-7 (FGF-7) and FGF-10. Western blotting identified the role of AA in the phosphorylation of various transcription factors (ERK, CREB, and AKT) and increased expression of Bcl-2 in hDPCs. In addition, AA significantly promoted hair shaft elongation, with increased proliferation of matrix keratinocytes, during ex vivo hair follicle culture. It was also found to promote hair growth by induction and prolongation of anagen phase in telogen-stage C57BL/6 mice. Conclusion This study concludes that AA plays a role in promoting hair growth by increasing the expression of growth factors in hDPCs and enhancing follicle proliferation and survival. PMID:26848219

  14. Monochloramine potently inhibits arachidonic acid metabolism in rat platelets.

    PubMed

    Fujimoto, Yohko; Ikeda, Mai; Sakuma, Satoru

    2006-05-26

    In the present study, the effects of hypochlorous acid (HOCl), monochloramine (NH(2)Cl), glutamine-chloramine (Glu-Cl) and taurine-chloramine (Tau-Cl) on the formation of 12-lipoxygenase (LOX) metabolite, 12-HETE, and cyclooxygenase (COX) metabolites, TXB(2), and 12-HHT, from exogenous arachidonic acid (AA) in rat platelets were examined. Rat platelets (4x10(8)/ml) were preincubated with drugs for 5min at 37 degrees C prior to the incubation with AA (40microM) for 2min at 37 degrees C. HOCl (50-250microM) showed an inhibition on the formation of LOX metabolite (12-HETE, 5-67% inhibition) and COX metabolites (TXB(2), 33-73% inhibition; 12-HHT, 27-74% inhibition). Although Tau-Cl and Glu-Cl up to 100microM were without effect on the formation of 12-HETE, TXB(2) and 12-HTT, NH(2)Cl showed a strong inhibition on the formation of all three metabolites (10-100microM NH(2)Cl, 12-HETE, 21-92% inhibition; TXB(2), 58-94% inhibition; 12-HHT, 36-92% inhibition). Methionine reversed a reduction of formation of LOX and COX metabolites induced by NH(2)Cl, and taurine restoring that induced by both NH(2)Cl and HOCl. These results suggest that NH(2)Cl is a more potent inhibitor of COX and LOX pathways in platelets than HOCl, and taurine and methionine can be modulators of NH(2)Cl-induced alterations in the COX and LOX pathways in vivo.

  15. In-vitro platelet responses to arachidonic acid in the rat.

    PubMed

    Rodriguez-Linares, B; Cano, E

    1995-12-01

    Using both the turbidimetric and the conductive methods to study aggregation of platelets, we found that arachidonic acid stimulated rat washed platelets in a dose-dependent manner (40 microM-0.5 mM). Although a high concentration of arachidonic acid (0.5 mM) produced an increase in light transmission both in the presence of 2 mM CaCl2 and EGTA (45.8 +/- 2.8 and 50.4 +/- 0.8% respectively) no changes in impedance were detected. Lysis caused by this concentration of arachidonic acid was very high at all the concentrations of calcium used (mean of 81.3%). In addition, the turbidimetric response induced by 0.5 mM arachidonic acid implied an initial decrease in light transmission but did not correlate with a real shape change. Forty micromolar arachidonic acid induced a calcium-dependent aggregation measured both by aggregometry and impedance. Morphology of aggregates induced by both concentrations was also studied. These results suggest that the optimal concentration for studying rat platelet activation by arachidonic acid is 40 microM; high concentrations (0.5 mM) cause aspecific effects not correlated to a physiological activation response.

  16. Activation and regulation of arachidonic acid release in rabbit peritoneal neutrophils

    SciTech Connect

    Tao, W.

    1988-01-01

    Arachidonic acid release in rabbit neutrophils can be enhanced by the addition of chemotactic fMet-Leu-Phe, platelet-activating factor, PAF, or the calcium ionophore A23187. Over 80% of the release ({sup 3}H)arachidonic acid comes from phosphatidylcholine and phosphatidylinositol. The release is dose-dependent and increases with increasing concentration of the stimulus. The A23187-induced release increases with increasing time of the stimulation. ({sup 3}H)arachidonic acid release, but not the rise in the concentration of intracellular calcium, is inhibited in pertussis toxin-treated neutrophils stimulated with PAF. The ({sup 3}H)arachidonic acid released by A23187 is potentiated while that release by fMET-Leu-Phe or PAF is inhibited in phorbol 12-myristate 13-acetate, PMA, treated rabbit neutrophils. The protein kinase C inhibitor 1-(5-isoquinoline sulfonyl)-2-methylpiperazine, H-7, has no effect on the potentiation by PMA of the A23187-induced release, it prevents the inhibition by PMA of the release produced by PAF or fMet-Leu-Phe. In addition, PMA increases arachidonic acid release in H-7-treated cells stimulated with fMet-Leu-Phe. The diacylglycerol kinase inhibitor R59022 increases the level of diacylglycerol in neutrophils stimulated with fMet-Leu-Phe. Furthermore, R59022 potentiates ({sup 3}H) arachidonic acid release produced by fMet-Leu-Phe. This potentiation is not inhibited by H-7, in fact, it is increased in H-7-treated neutrophils.

  17. In vitro release of arachidonic acid and in vivo responses to respirable fractions of cotton dust

    SciTech Connect

    Thomson, T.A.; Edwards, J.H.; Al-Zubaidy, T.S.; Brown, R.C.; Poole, A.; Nicholls, P.J.

    1986-04-01

    It was considered that the fall in lung function seen after exposure to cotton dust may be attributable in part to the activity of arachidonic acid metabolites, such as leucotrienes as well as to the more established release of histamine by cotton dust. However, we found that cotton and barley dusts elicited poor release of arachidonic acid from an established macrophage like cell line compared with that observed with other organic dusts. In the experimental animal, pulmonary cellular responses to both cotton and barley dust were similar to those evoked by moldy hay and pigeon dropping dusts, although after multiple doses a more severe response was seen to cotton and barley. Since both moldy hay and pigeon droppings elicit a greater arachidonic acid release than cotton or barley, a role for arachidonic acid in inducing the cellular response is less likely than other factors. There are limitations to our conclusions using this system, i.e., the arachidonic acid may be released in a nonmetabolized form, although it is noted that the two dusts with the greatest arachidonic acid release produce their clinical responses in humans largely by hypersensitivity mechanisms.

  18. Hepatic arachidonic acid metabolism is disrupted after hexachlorobenzene treatment.

    PubMed

    Billi de Catabbi, Silvia C; Faletti, Alicia; Fuentes, Federico; San Martín de Viale, Leonor C; Cochón, Adriana C

    2005-04-15

    Hexaclorobenzene (HCB), one of the most persistent environmental pollutants, can cause a wide range of toxic effects including cancer in animals, and hepatotoxicity and porphyria both in humans and animals. In the present study, liver microsomal cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolism, hepatic PGE production, and cytosolic phospholipase A2 (cPLA2) activity were investigated in an experimental model of porphyria cutanea tarda induced by HCB. Female Wistar rats were treated with a single daily dose of HCB (100 mg kg(-1) body weight) for 5 days and were sacrificed 3, 10, 17, and 52 days after the last dose. HCB treatment induced the accumulation of hepatic porphyrins from day 17 and increased the activities of liver ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), and aminopyrine N-demethylase (APND) from day 3 after the last dose. Liver microsomes from control and HCB-treated rats generated, in the presence of NADPH, hydroxyeicosatetraenoic acids (HETEs), epoxyeicosatrienoic acids (EETs), 11,12-Di HETE, and omega-OH/omega-1-OH AA. HCB treatment caused an increase in total NADPH CYP-dependent AA metabolism, with a higher response at 3 days after the last HCB dose than at the other time points studied. In addition, HCB treatment markedly enhanced PGE production and release in liver slices. This HCB effect was time dependent and reached its highest level after 10 days. At this time cPLA2 activity was shown to be increased. Unexpectedly, HCB produced a significant decrease in cPLA2 activity on the 17th and 52nd day. Our results demonstrated for the first time that HCB induces both the cyclooxygenase and CYP-dependent AA metabolism. The effects of HCB on AA metabolism were previous to the onset of a marked porphyria and might contribute to different aspects of HCB-induced liver toxicity such as alterations of membrane fluidity and membrane-bound protein function. Observations also suggested that a possible role of cPLA2

  19. Anti-inflammatory signaling actions of electrophilic nitro-arachidonic acid in vascular cells and astrocytes.

    PubMed

    Trostchansky, Andrés; Rubbo, Homero

    2017-03-01

    Nitrated derivatives of unsaturated fatty acids (nitro-fatty acids) are being formed and detected in human plasma, cell membranes and tissue, triggering signaling cascades via covalent and reversible post-translational modifications of nucleophilic amino acids in transcriptional regulatory proteins. Arachidonic acid (AA) represents a precursor of potent signaling molecules, i.e., prostaglandins and thromboxanes through enzymatic and non-enzymatic oxidative pathways. Arachidonic acid can be nitrated by reactive nitrogen species leading to the formation of nitro-arachidonic acid (NO2-AA). A critical issue is the influence of NO2-AA on prostaglandin endoperoxide H synthases, modulating inflammatory processes through redirection of AA metabolism and signaling. In this prospective article, we describe the key chemical and biochemical actions of NO2-AA in vascular and astrocytes. This includes the ability of NO2-AA to mediate unique redox signaling anti-inflammatory actions along with its therapeutic potential.

  20. Efficacy of dietary arachidonic acid provided as triglyceride or phospholipid as substrates for brain arachidonic acid accretion in baboon neonates.

    PubMed

    Wijendran, Vasuki; Huang, Meng-Chuan; Diau, Guan-Yeu; Boehm, Günther; Nathanielsz, Peter W; Brenna, J Thomas

    2002-03-01

    Arachidonic acid (AA) is a long-chain polyunsaturate (LCP) present in human breast milk as both triglyceride (TG) and as phospholipid (PL). There has been little attention to the metabolic consequences of lipid form of AA in infant formulas. Our objective was to investigate the efficacy of dietary TG and PL as carriers of AA for accretion in the brain and associated organs of term baboon neonates consuming a formula with LCP composition typical of human milk. TG and phosphatidylcholine (PC) with [U-(13)C]-AA in the sn-2 position and with unlabeled 16:0 in the remaining positions (TG-AA* or PL-AA*, respectively) were used as tracers to study the tissue AA* incorporation. Baboon neonates received a single oral dose of either TG-AA* (n = 3) or PL-AA* (n = 4) at 18-19 d of life. Tissues were obtained 10 d later (28-29 d of life) and isotopic enrichment was measured. In the brain, 4.5% of the PL-AA* dose and 2.1% of the TG-AA* dose were recovered as brain AA*, respectively, indicating that PL was about 2.1-fold more effective than TG as a substrate for brain AA accretion. Preferential incorporation of PL-derived AA* over TG source of AA* was also observed in the liver, lung, plasma, and erythrocytes. Because of the quantitative predominance of TG-AA in formula, total brain AA accretion, expressed as absolute weight, was 5.0-fold greater from TG-AA than from PL-AA. We estimate that about half of postnatal brain AA accretion is derived from dietary preformed AA in term baboon neonates consuming a formula with lipid composition similar to that of human milk.

  1. Effects of arachidonic acid on FFA4 receptor: Signaling, phosphorylation and internalization.

    PubMed

    Villegas-Comonfort, S; Takei, Y; Tsujimoto, G; Hirasawa, A; García-Sáinz, J A

    2017-02-01

    Arachidonic acid increased intracellular calcium, in cells expressing green fluorescent protein-tagged human FFA4 receptors, with an EC50 of ~40µM. This action was not blocked by cyclooxygenase or lipoxigenase inhibitors but it was inhibited by AH7614, a FFA4 antagonist. Arachidonic acid induced ERK activation accompanied by EGF receptor transactivation. However, EGF transactivation was not the major mechanism through which the fatty acid induced ERK phosphorylation, as evidenced by the inability of AG1478 to block it. Arachidonic acid increased FFA4 receptor phosphorylation that reached its maximum within 15min with an EC50 of ~30µM; inhibitors of protein kinase C partially diminish this effect and AH7614 blocked it. Arachidonic acid induced rapid and sustained Akt/PKB phosphorylation and FFA4 - β-arrestin interaction. Confocal microscopy evidenced that FFA4 receptor activation and phosphorylation were associated to internalization. In conclusion, arachidonic acid is a bona fide FFA4 receptor agonist.

  2. Identification of an Arachidonic Acid-Producing Bacterium and Description of Kineococcus arachidonicus sp. nov.

    SciTech Connect

    Fliermans, C.B.

    2001-05-15

    The identification of bacterial with the ability to produce polyunsaturated fatty acids as been limited almost exclusively to gram-negative, psychrophilic, marine microorganisms. Here we describe a new gram-type-positive bactgerium, strain SRS30216T, that produces the polyunsaturated fatty acid, arachidonic acid, and is neither psychrophilic nor a marine isolate.

  3. Maternal arachidonic acid supplementation improves neurodevelopment of offspring from healthy and diabetic rats.

    PubMed

    Zhao, Jinping; Del Bigio, Marc R; Weiler, Hope A

    2009-01-01

    Maternal diabetes may compromise infant arachidonic acid status and development. This study tested if maternal arachidonic acid supplementation improves neurodevelopment in rat offspring. Dams were randomized into 6 groups using a 3x2 design: Saline-Placebo, streptozotocin-induced diabetes with glucose controlled at <13mmol/L, or poorly controlled at 13-20mmol/L using insulin; and fed either control or an arachidonic acid (0.5% of fat) diet throughout reproduction. Offspring were tested on post-natal days 3 and 5 for righting response, days 7 and 9 for negative geotaxis, day 14 for wire hanging endurance, days 18 and 24 for rota rod endurance, and day 28 for Morris water maze performance. Only the poorly controlled group had impaired day 7 geotaxis and day 18 rota rod performance (p<0.02), but this improved with maternal arachidonic acid supplementation (p<0.0006). Arachidonic acid improved the wire hanging endurance (p=0.0003) and water maze latency (p=0.0021), suggesting enhanced neurodevelopment in all offspring.

  4. Changes in arachidonic acid metabolism in UV-irradiated hairless mouse skin

    SciTech Connect

    Ruzicka, T.; Walter, J.F.; Printz, M.P.

    1983-10-01

    This study was conducted to investigate the metabolism of arachidonic acid in the skin of hairless mice exposed to UVA, PUVA, UVB, and UVC irradiation. The main products of arachidonic acid in the epidermis were hydroxyeicosatetraenoic acid (HETE), PGE2, and PGD2. Dermis displayed a lower lipoxygenase activity (expressed as HETE production) than the epidermis and showed no detectable cyclooxygenase activity, i.e., no prostaglandin production. The main changes observed in UV-induced inflammatory reactions were as follows. 1. A 5-fold increase in dermal HETE production in PUVA-treated animals and a 29% reduction in epidermal HETE formation after UVC treatment. 2. A marked decrease of PGD2 and a marked increase of PGE2 formation due to alterations of PGH2 metabolism in the UVB-treated group; however, cyclooxygenase activity was unchanged. These changes in arachidonic acid metabolism in the skin may be of pathophysiologic importance in UV-induced inflammatory reaction.

  5. Neuroprotective effects of arachidonic acid against oxidative stress on rat hippocampal slices.

    PubMed

    Wang, Ze-Jian; Liang, Cui-Ling; Li, Guang-Mei; Yu, Cai-Yi; Yin, Ming

    2006-11-07

    Arachidonic acid (AA), 5,8,11,14-eicosateraenoic acid is abundant, active and necessary in the human body. In the present study, we reported the neuroprotective effects and mechanism of arachidonic acid on hippocampal slices insulted by glutamate, NaN(3) or H(2)O(2)in vitro. Different types of models of brain injury in vitro were developed by 1mM glutamate, 10mM NaN(3) or 2mM H(2)O(2). After 30 min of preincubation with arachidonic acid or linoleic acid, hippocampal slices were subjected to glutamate, NaN(3) or H(2)O(2), then the tissue activities were evaluated by using the 2,3,5-triphenyltetrazolium chloride method. Endogenous antioxidant enzymes activities (SOD, GSH-PX and catalase) in hippocampal slices were evaluated during the course of incubation. MK886 (5 microM; a noncompetitive inhibitor of proliferator-activated receptor [PPAR]alpha), BADGE (bisphenol A diglycidyl ether; 100 microM; an antagonist of PPARgamma) and cycloheximide (CHX; 30 microM; an inhibitor of protein synthesis) were tested for their effects on the neuroprotection afforded by arachidonic acid. Population spikes were recorded in randomly selected hippocapal slices. Arachidonic acid (1-10 microM) dose dependently protected hippocampal slices from glutamate and H(2)O(2) injury (P<0.01), and arachidonic acid (10 microM) can significantly improve the activities of Cu/Zn-SOD in hippocampal slices after 1h incubation. In addition, 10 microM arachidonic acid significantly increased the activity of Mn-SOD and catalase, and decreased the activities of Cu/Zn-SOD to control value after 3h incubation. These secondary changes of SOD during incubation can be reversed by indomethacine (10 microM; a nonspecific cyclooxygenase inhibitor) or AA 861 (20 microM; a 5-lipoxygenase inhibitor). Its neuroprotective effect was completely abolished by BADGE and CHX. These observations reveal that arachidonic acid can defense against oxidative stress by boosting the internal antioxidant system of hippocampal slices

  6. Effect of progesterone on the release of arachidonic acid from human endometrial cells stimulated by histamine

    SciTech Connect

    Wilson, T.; Liggins, G.C.; Aimer, G.P.; Watkins, E.J.

    1986-02-01

    Progesterone at concentrations of 10(-7)M and 10(-8)M inhibits release of (/sup 3/H)-arachidonic acid from stimulated, perfused, endometrial cells. The effect is independent of the mechanism of stimulation. Cortisol (10(-5)M but not 10(-7)M) has a similar effect in this system but estradiol (10(-7)M) is without effect. There was a positive correlation (p less than 0.05) between the magnitude of inhibition by progesterone and the day of cycle. The inhibitory action of progesterone on the release of arachidonic acid was greater in endometrial cells than in decidual cells and was apparent after fifteen minutes. The activities of commercial and endometrial cell-free preparations of phospholipase A2 and phospholipase C were unaffected by the presence of progesterone. We conclude that progesterone modulates release of (/sup 3/H)-arachidonic acid from endometrial cells by a rapid, indirect action on phospholipase activity.

  7. The presence of arachidonic acid-activated K+ channel, TREK-1, in human periodontal ligament fibroblasts.

    PubMed

    Saeki, Yukikazu; Ohara, Akito; Nishikawa, Masanori; Yamamoto, Takahiro; Yamamoto, Gaku

    2007-01-01

    Human periodontal ligament (PDL) fibroblasts expressed following two-pore-domain K(+) channels, TWIK-2 > TREK-1 > TWIK-1 > TASK-1 > TRAAK > TASK-2. TREK-2 message was not detectable. We found the presence of arachidonic acid-activated and mechanical stress-sensitive K(+) channel, TREK-1, in the PDL fibroblasts by patch-clamp technique. It was also found the significant increase of intracellular concentration of arachidonic acid upon the application of cyclic stretch. Therefore, we suppose that the mechanical stretch due to the mastication activates phospholipase A(2) to release arachidonic acid (AA) from membrane, then, the released AA activates TREK-1. Thus, TREK-1 K(+) channels may play a protective role to maintain the negative membrane potential of PDL fibroblasts against the environmental stimuli.

  8. The effect of fluid mechanical stress on cellular arachidonic acid metabolism

    NASA Technical Reports Server (NTRS)

    Mcintire, L. V.; Frangos, J. A.; Rhee, B. G.; Eskin, S. G.; Hall, E. R.

    1987-01-01

    The effect of sublytic levels of mechanical perturations of cells on cell metabolism were investigated by analyzing the products of arachidonic acid (used as a marker metabolite) in blood platelets, polymorphonuclear leucocytes, and cultured umbilical-vein endothelial cells after the suspensions of these cells were subjected to a shear stress in a modified viscometer. It is shown that the sublytic levels of mechanical stress stimulated the arachidonic acid metabolism in all these cell types. Possible biological implications of this stress-metabolism coupling are discussed.

  9. [Antiaggregation activity of arachidonic acid conjugates with neurotropic peptides proglyprol and semax].

    PubMed

    Bezuglov, V V; Gretskaia, N M; Vasil'eva, T M; Petrukhina, G N; Andreeva, L A; Miasoedov, N F; Makarov, V A

    2014-01-01

    The influence two original derivatives of a therapeutically important peptide, bearing arachidonic acid residue with semax and proglyprol, upon platelet aggregation have been studied in vitro. It is established that both derivatives, in contrast to the parent peptide, possess moderate anti-aggregant properties and produce a dose-dependent decrease in the interplatelet interaction induced by ADP, epinephrine, and arachidonic acid within the concentration range of 0.018 - 1.8 mM. This activity was more pronounced for arachidonoylsemax in comparison with arachidonoylproglyprol.

  10. Relationships between Arachidonic Acid, Uterine Activity and Metabolic Regulation of Placental Lactogen Secretion.

    DTIC Science & Technology

    1982-08-01

    variations and to determine the metabolic role of oPL during gestation. Fasting, which decreased plasma glucose and increased plasma free fatty acid ... fatty acids induced by fasting or to have diabetogenic effects. The intravenous administration of 12.5 or 25 mg of arachidonic acid resulted in a...of hPL is thought to be controlled by the plasma con- centrations of the metabolic substrates; carbohydrate, fat or protein. Plasma free fatty acid

  11. Eicosapentaenoic acid and arachidonic acid: collaboration and not antagonism is the key to biological understanding.

    PubMed

    Horrobin, D F; Jenkins, K; Bennett, C N; Christie, W W

    2002-01-01

    Much of the literature on omega-3 and omega-6 fatty acids suggests that desirable effects of omega-3 fatty acids are in part related to depletion of arachidonic acid (AA). However, in rats and humans, we have found that low doses of EPA actually elevate membrane AA phospholipid concentrations. In patients with schizophrenia, treatment with eicosapentaenoic acid (EPA) produced clinical improvement, but that improvement was greater at a dose of 2 g/day than at 4 g/day. The improvement was not significantly correlated with changes in either EPA or docosahexaenoic acid (DHA) but was highly significantly positively correlated with rises in red cell membrane AA. We suggest that elevation of concentrations of both AA and EPA in cell membranes may be important for health.

  12. Effect of Arachidonic Acid on Twitch Tension of the Rat Phrenic Nerve- Diaphragm

    DTIC Science & Technology

    1992-01-01

    arachidonic acid-induced re- KANDASAMY , S . Bt. AND HUNT, W. A.; Arachidonic at-id and prostaglandins duction of twitch tension, both tended to attenuate the...samy and Hunt, 1990). It has also been reported to modulate t la.Teognbt ouin10mtws18m ’~ 2 1mto clean. The organ bath s l tion (61) ml I was 1.8• mM...Act (U.S.) and the 10% of the corresponding mean. Received for publication March 27, 1992. Results S A preliminary account of this research wan

  13. Fatty acid remodeling by LPCAT3 enriches arachidonate in phospholipid membranes and regulates triglyceride transport

    PubMed Central

    Hashidate-Yoshida, Tomomi; Harayama, Takeshi; Hishikawa, Daisuke; Morimoto, Ryo; Hamano, Fumie; Tokuoka, Suzumi M; Eto, Miki; Tamura-Nakano, Miwa; Yanobu-Takanashi, Rieko; Mukumoto, Yoshiko; Kiyonari, Hiroshi; Okamura, Tadashi; Kita, Yoshihiro; Shindou, Hideo; Shimizu, Takao

    2015-01-01

    Polyunsaturated fatty acids (PUFAs) in phospholipids affect the physical properties of membranes, but it is unclear which biological processes are influenced by their regulation. For example, the functions of membrane arachidonate that are independent of a precursor role for eicosanoid synthesis remain largely unknown. Here, we show that the lack of lysophosphatidylcholine acyltransferase 3 (LPCAT3) leads to drastic reductions in membrane arachidonate levels, and that LPCAT3-deficient mice are neonatally lethal due to an extensive triacylglycerol (TG) accumulation and dysfunction in enterocytes. We found that high levels of PUFAs in membranes enable TGs to locally cluster in high density, and that this clustering promotes efficient TG transfer. We propose a model of local arachidonate enrichment by LPCAT3 to generate a distinct pool of TG in membranes, which is required for normal directionality of TG transfer and lipoprotein assembly in the liver and enterocytes. DOI: http://dx.doi.org/10.7554/eLife.06328.001 PMID:25898003

  14. Pathological regulation of arachidonic acid release in cystic fibrosis: the putative basic defect.

    PubMed Central

    Carlstedt-Duke, J; Brönnegård, M; Strandvik, B

    1986-01-01

    The regulation of arachidonic acid release from membrane phospholipids was investigated in lymphocytes from patients with cystic fibrosis as well as control patients. No effect of either dexamethasone or fetal calf serum was seen on arachidonic acid release from cystic fibrosis lymphocytes, in contrast to control lymphocytes. In the latter cells, arachidonic acid release was inhibited by dexamethasone, fetal calf serum, or both. There were no differences in glucocorticoid receptor in lymphocytes from the two groups with regard to Kd and number of binding sites per cell. Furthermore, dexamethasone inhibited the incorporation of thymidine into lymphocytes from either group, indicating a normal functional glucocorticoid receptor. The defective regulation of arachidonic acid, resulting in an increased turnover, can explain many of the findings in cystic fibrosis, and we hypothesize that it is the basic defect causing the disease. The defect occurs at a level after the glucocorticoid receptor, which is functionally normal, and involves either the glucocorticoid-dependent phospholipase-inhibitory protein lipomodulin (lipocortin) or phospholipase A2. PMID:3097647

  15. Hyperglycemia-induced teratogenesis is mediated by a functional deficiency of arachidonic acid.

    PubMed Central

    Goldman, A S; Baker, L; Piddington, R; Marx, B; Herold, R; Egler, J

    1985-01-01

    Congenital malformations now represent the largest single cause of mortality in the infant of the diabetic mother. The mechanism by which diabetes exerts its teratogenic effects is not known. This study evaluated whether arachidonic acid might be involved, a possibility raised by the role of arachidonic acid in palatal elevation and fusion, processes analogous to neural tube folding and fusion. This hypothesis was tested in two animal models of diabetic embryopathy, the in vivo pregnant diabetic rat and the in vitro hyperglycemic mouse embryo culture. The subcutaneous injection of arachidonic acid (200-400 mg/kg per day) into pregnant diabetic rats during the period of organ differentiation (days 6-12) did not alter the maternal glucose concentration, the maternal weight gain, or the weight of the embryos. However, the incidence of neural tube fusion defects was reduced from 11% to 3.8% (P less than 0.005), the frequency of cleft palate was reduced from 11% to 4% (P less than 0.005), and the incidence of micrognathia was reduced from 7% to 0.8% (P less than 0.001). The addition of arachidonic acid to B10.A mouse embryos in culture also resulted in a reversal of hyperglycemia-induced teratogenesis. The teratogenic effect of D-glucose (8 mg/ml) in the medium resulted in normal neural tube fusion in only 32% of the embryos (P less than 0.006 when compared to controls). Arachidonic acid supplementation (1 or 10 micrograms/ml) produced a rate of neural tube fusion (67%) that was not significantly different from that observed in controls. The evidence presented indicates that arachidonic acid supplementation exerts a significant protective effect against the teratogenic action of hyperglycemia in both in vivo (rat) and in vitro (mouse) animal models. These data therefore suggest that the mechanism mediating the teratogenic effect of an increased glucose concentration involves a functional deficiency of arachidonic acid at a critical stage of organogenesis. Images PMID

  16. cAMP increases mitochondrial cholesterol transport through the induction of arachidonic acid release inside this organelle in Leydig cells.

    PubMed

    Castillo, Ana Fernanda; Cornejo Maciel, Fabiana; Castilla, Rocío; Duarte, Alejandra; Maloberti, Paula; Paz, Cristina; Podestá, Ernesto J

    2006-11-01

    We have investigated the direct effect of arachidonic acid on cholesterol transport in intact cells or isolated mitochondria from steroidogenic cells and the effect of cyclic-AMP on the specific release of this fatty acid inside the mitochondria. We show for the first time that cyclic-AMP can regulate the release of arachidonic acid in a specialized compartment of MA-10 Leydig cells, e.g. the mitochondria, and that the fatty acid induces cholesterol transport through a mechanism different from the classical pathway. Arachidonic acid and arachidonoyl-CoA can stimulate cholesterol transport in isolated mitochondria from nonstimulated cells. The effect of arachidonoyl-CoA is inhibited by the reduction in the expression or in the activity of a mitochondrial thioesterase that uses arachidonoyl-CoA as a substrate to release arachidonic acid. cAMP-induced arachidonic acid accumulation into the mitochondria is also reduced when the mitochondrial thioesterase activity or expression is blocked. This new feature in the regulation of cholesterol transport by arachidonic acid and the release of arachidonic acid in specialized compartment of the cells could offer novel means for understanding the regulation of steroid synthesis but also would be important in other situations such as neuropathological disorders or oncology disorders, where cholesterol transport plays an important role.

  17. Phosphate limitation promotes unsaturated fatty acids and arachidonic acid biosynthesis by microalgae Porphyridium purpureum.

    PubMed

    Su, Gaomin; Jiao, Kailin; Li, Zheng; Guo, Xiaoyi; Chang, Jingyu; Ndikubwimana, Theoneste; Sun, Yong; Zeng, Xianhai; Lu, Yinghua; Lin, Lu

    2016-07-01

    Polyunsaturated fatty acids (PUFAs) are highly appreciated on their nutritive value for human health and aquaculture. P. purpureum, one of the red microalgae acknowledged as a promising accumulator of ARA, was chosen as the target algae in the present research. Effects of sodium bicarbonate (0.04-1.2 g/L), temperature (25, 30 and 33 °C) and phosphate (0.00-0.14 g/L) on biomass yield, total fatty acids (TFA) and arachidonic acid (ARA) accumulation were investigated systemically. NaHCO3 dose of 0.8 g/L and moderate temperature of 30 °C were preferred. In addition, TFA and ARA production were significantly enhanced by an appropriate concentration of phosphate, and the highest TFA yield of 666.38 mg/L and ARA yield of 159.74 mg/L were obtained at a phosphate concentration of 0.035 g/L. Interestingly, with phosphate concentration continuing to fall, UFA/TFA and ARA/EPA ratios were increased accordingly, suggesting that phosphate limitation promoted unsaturated fatty acids and arachidonic acid biosynthesis. Low concentration of phosphate may be favored to increase the enzymatic activities of ∆6-desaturase, which played a key role in catalyzing the conversion of C16:0 to C18:2, and thus the selectivity of UFA increased. Meanwhile, the increase of ARA selectivity could be attributed to ω6 pathway promotion and ∆17-desaturase activity inhibition with phosphate limitation. Phosphate limitation strategy enhanced unsaturated fatty acids and ARA biosynthesis in P. purpureum, and can be applied in commercial scale manufacturing and commercialization of ARA.

  18. Incorporation and distribution of dihomo-gamma-linolenic acid, arachidonic acid, and eicosapentaenoic acid in cultured human keratinocytes

    SciTech Connect

    Punnonen, K.; Puustinen, T.; Jansen, C.T.

    1986-02-01

    Human keratinocytes in culture were labelled with /sup 14/C-dihomo-gamma-linolenic acid, /sup 14/C-arachidonic acid or /sup 14/C-eicosapentaenoic acid. All three eicosanoid precursor fatty acids were effectively incorporated into the cells. In phospholipids most of the radioactivity was recovered, in neutral lipids a substantial amount, and as free unesterified fatty acids only a minor amount. Most of the radioactivity was found in phosphatidylethanolamine which was also the major phospholipid as measured by phosphorous assay. The incorporation of dihomo-gamma-linolenic acid and arachidonic acid into lipid subfractions was essentially similar. Eicosapentaenoic acid was, however, much less effectively incorporated into phosphatidylinositol + phosphatidylserine and, correspondingly, more effectively into triacylglycerols as compared to the two other precursor fatty acids. Once incorporated, the distribution of all three precursor fatty acids was relatively stable, and only minor amounts of fatty acids were released into the culture medium during short term culture (two days). Our study demonstrates that eicosanoid precursor fatty acids are avidly taken up by human keratinocytes and esterified into membrane lipids. The clinical implication of this finding is that dietary manipulations might be employed to cause changes in the fatty acid composition of keratinocytes.

  19. Significant utilization of dietary arachidonic acid is for brain adrenic acid in baboon neonates.

    PubMed

    Wijendran, Vasuki; Lawrence, Peter; Diau, Guan-Yeu; Boehm, G; Nathanielsz, P W; Brenna, J T

    2002-05-01

    Dietary arachidonic acid (20:4n-6) utilization in-vivo for carbon recycling into de-novo lipogenesis and conversion to n-6 long chain polyunsaturates was investigated in baboon neonates using [U-(13)C]20:4n-6. Neonates consuming a formula typical of human milk received a single oral dose of [(13)C]arachidonic acid in sn-2 position of either triglyceride or phosphatidylcholine at 18-19 days of postnatal life. Neonate brain, retina, liver, and plasma were obtained 10 days later (28-29 days of life). Low isotopic enrichment (0.27-1.0%Total label) was detected in dihomo-gamma-linolenic acid (20:3n-6) in all tissues, but label incorporation into saturates or monounsaturates was not detected. In neonate brain and retina, 16% and 11% of total label was recovered in 22:4n-6, respectively. The relative contribution of dietary fatty acids to postnatal brain 22:4n-6 accretion can be estimated for dietary 20:4n-6 and preformed 22:4n-6 as 17% and 8%, respectively, corresponding to efficiencies of 0.48% and 0.54% of dietary levels, respectively. These results demonstrate in term baboon neonates that in vivo 1) 20:4n-6 was retroconverted to 20:3n-6, 2) 20:4n-6 did not contribute significantly to de novo lipogenesis of saturates and monounsaturates, and 3) the preformed 20:4n-6 contribution to brain 22:4n-6 accumulation was quantitatively a significant metabolic fate for dietary 20:4n-6.

  20. Amyloid Plaque-Associated Oxidative Degradation of Uniformly Radiolabeled Arachidonic Acid.

    PubMed

    Furman, Ran; Murray, Ian V J; Schall, Hayley E; Liu, Qiwei; Ghiwot, Yonatan; Axelsen, Paul H

    2016-03-16

    Oxidative stress is a frequently observed feature of Alzheimer's disease, but its pathological significance is not understood. To explore the relationship between oxidative stress and amyloid plaques, uniformly radiolabeled arachidonate was introduced into transgenic mouse models of Alzheimer's disease via intracerebroventricular injection. Uniform labeling with carbon-14 is used here for the first time, and made possible meaningful quantification of arachidonate oxidative degradation products. The injected arachidonate entered a fatty acid pool that was subject to oxidative degradation in both transgenic and wild-type animals. However, the extent of its degradation was markedly greater in the hippocampus of transgenic animals where amyloid plaques were abundant. In human Alzheimer's brain, plaque-associated proteins were post-translationally modified by hydroxynonenal, a well-known oxidative degradation product of arachidonate. These results suggest that several recurring themes in Alzheimer's pathogenesis, amyloid β proteins, transition metal ions, oxidative stress, and apolipoprotein isoforms, may be involved in a common mechanism that has the potential to explain both neuronal loss and fibril formation in this disease.

  1. Differential stimulation of luminol-enhanced chemiluminescence (CL) and arachidonic acid metabolism in rat peritoneal neutrophils

    SciTech Connect

    Sturm, R.J.; Adams, L.M.; Cullinan, C.A.; Berkenkopf, J.W.; Weichman, B.M.

    1986-03-05

    Phorbol 12-myristate, 13-acetate (PMA) induced the production of radical oxygen species (ROS) from rat peritoneal neutrophils as assessed by CL. ROS generation occurred in a time- (maximum at 13.5 min) and dose- (concentration range of 1.7-498 nM) related fashion. However, 166 nM PMA did not induce either cyclooxygenase (CO) or lipoxygenase (LPO) product formation by 20 min post-stimulation. Conversely, A23187, at concentrations between 0.1 and 10 ..mu..M, stimulated both pathways of arachidonic acid metabolism, but had little or no effect upon ROS production. When suboptimal concentrations of PMA (5.5 nM) and A23187 (0.1-1 ..mu..M) were coincubated with the neutrophils, a synergistic ROS response was elicited. However, arachidonic acid metabolism in the presence of PMA was unchanged relative to A12187 alone. Nordihydroguaiaretic acid (NDGA) inhibited both PMA-induced CL (IC/sub 50/ = 0.9 ..mu..M) and A23187-induced arachidonic acid metabolism (IC/sub 50/ = 1.7 ..mu..M and 6.0 ..mu..M for LPO and CO, respectively). The mixed LPO-CO inhibitor, BW755C, behaved in a qualitatively similar manner to NDGA, whereas the CO inhibitors, indomethacin, piroxicam and naproxen had no inhibitory effect on ROS generation at concentrations as high as 100 ..mu..M. These results suggest that NDGA and BW755C may inhibit CL and arachidonic acid metabolism by distinct mechanisms in rat neutrophils.

  2. [Controlling arachidonic acid metabolic network: from single- to multi-target inhibitors of key enzymes].

    PubMed

    Liu, Ying; Chen, Zheng; Shang, Er-chang; Yang, Kun; Wei, Deng-guo; Zhou, Lu; Jiang, Xiao-lu; He, Chong; Lai, Lu-hua

    2009-03-01

    Inflammatory diseases are common medical conditions seen in disorders of human immune system. There is a great demand for anti-inflammatory drugs. There are major inflammatory mediators in arachidonic acid metabolic network. Several enzymes in this network have been used as key targets for the development of anti-inflammatory drugs. However, specific single-target inhibitors can not sufficiently control the network balance and may cause side effects at the same time. Most inflammation induced diseases come from the complicated coupling of inflammatory cascades involving multiple targets. In order to treat these complicated diseases, drugs that can intervene multi-targets at the same time attracted much attention. The goal of this review is mainly focused on the key enzymes in arachidonic acid metabolic network, such as phospholipase A2, cyclooxygenase, 5-lipoxygenase and eukotriene A4 hydrolase. Advance in single target and multi-targe inhibitors is summarized.

  3. Estrogens protect against hydrogen peroxide and arachidonic acid induced DNA damage.

    PubMed

    Tang, M; Subbiah, M T

    1996-01-19

    The ability of estrogens to protect against DNA damage induced by either hydrogen peroxide or arachidonic acid alone or in combination with Cu2+ was investigated. DNA strand breaks were determined by conversion of double stranded supercoiled OX-174 RFI DNA to double stranded open circular DNA and linear single stranded DNA. Estradiol-17 beta significantly decreased the formation of single and double strand breaks in DNA induced by H2O2 alone or with Cu2+. Equilin (an equine estrogen) was more effective than estradiol-17 beta at the doses tested. Arachidonic acid in the presence of Cu2+ caused the formation of high levels of linear DNA which was protected by estrogen with equilen being more effective. These studies suggest that estrogens through this protective effect on DNA damage might contribute to cardioprotection.

  4. Expression analysis for genes involved in arachidonic acid biosynthesis in Mortierella alpina CBS 754.68.

    PubMed

    Samadlouie, Hamid-Reza; Hamidi-Esfahani, Zohreh; Alavi, Seyed-Mehdi; Varastegani, Boshra

    2014-01-01

    The time courses for production of fungal biomass, lipid, phenolic and arachidonic acid (ARA) as well as expression of the genes involved in biosynthesis of ARA and lipid were examined in Mortierella alpina CBS 754.68. A significant increase in the arachidonic acid content in lipids that coincided with reduced levels of lipid was obtained. Reduced gene expression occurred presumably due to the steady reduction of carbon and nitrogen resources. However, these energy resources were inefficiently compensated by the breakdown of the accumulated lipids that in turn, induced up-regulated expression of the candidate genes. The results further indicated that the expression of the GLELO encoding gene is a rate-limiting step in the biosynthesis of ARA in the early growth phase.

  5. Occurrence of oxidized metabolites of arachidonic acid esterified to phospholipids in murine lung tissue.

    PubMed

    Nakamura, T; Henson, P M; Murphy, R C

    1998-08-15

    Isolation and characterization of murine pulmonary phospholipids revealed the normal occurrence of 10 isobaric eicosanoids corresponding to the incorporation of one oxygen atom into the arachidonate esterified to glycerophospholipids. Lungs from mice were removed and lipids were extracted and then separated into free carboxylic acid and phospholipids. Phospholipids were hydrolyzed to yield the free carboxylic acids prior to analysis. Reverse-phase HPLC and electrospray tandem mass spectrometry were used to identify and quantitate six monohydroxyeicosatetraenoic (HETE) and four epoxyeicosatetraenoic (EET) acid regioisomers using d8-HETE as internal standard. HETEs esterified to phospholipids were found to increase following intratracheal administration of tBuOOH (36 mg/kg), but not the levels of esterified EETs. Chiral analysis of esterified 15-HETE revealed an R/S ratio of 0.96, suggesting operation of a free radical mechanism responsible for generation of this monohydroxy arachidonate phospholipid, and this enantiomeric ratio was 1.10 following treatment of the mouse lung with tBuOOH. These results are consistent with a free-radical-based mechanism of oxidation of pulmonary glycerophospholipids containing arachidonate.

  6. Plasma oxylipin profiling identifies polyunsaturated vicinal diols as responsive to arachidonic acid and docosahexaenoic acid intake in growing piglets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dose-responsiveness of plasma oxylipins to incremental dietary intake of arachidonic (20:4n-6; ARA) and docosahexaenoic (22:6n-3; DHA) acid was determined in piglets. Piglets randomly received one of six formulas (n=8 per group) from day 3 to 27 postnatally. Diets contained varying ARA and DHA l...

  7. Deficits in docosahexaenoic acid and associated elevations in the metabolism of arachidonic acid and saturated fatty acids in the postmortem orbitofrontal cortex of patients with bipolar disorder.

    PubMed

    McNamara, Robert K; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Stanford, Kevin E; Hahn, Chang-Gyu; Richtand, Neil M

    2008-09-30

    Previous antemortem and postmortem tissue fatty acid composition studies have observed significant deficits in the omega-3 fatty acid docosahexaenoic acid (DHA, 22:6n-3) in red blood cell (RBC) and postmortem cortical membranes of patients with unipolar depression. In the present study, we determined the fatty acid composition of postmortem orbitofrontal cortex (OFC, Brodmann area 10) of patients with bipolar disorder (n=18) and age-matched normal controls (n=19) by gas chromatography. After correction for multiple comparisons, DHA (-24%), arachidonic acid (-14%), and stearic acid (C18:0) (-4.5%) compositions were significantly lower, and cis-vaccenic acid (18:1n-7) (+12.5%) composition significantly higher, in the OFC of bipolar patients relative to normal controls. Based on metabolite:precursor ratios, significant elevations in arachidonic acid, stearic acid, and palmitic acid conversion/metabolism were observed in the OFC of bipolar patients, and were inversely correlated with DHA composition. Deficits in OFC DHA and arachidonic acid composition, and elevations in arachidonic acid metabolism, were numerically (but not significantly) greater in drug-free bipolar patients relative to patients treated with mood-stabilizer or antipsychotic medications. OFC DHA and arachidonic acid deficits were greater in patients plus normal controls with high vs. low alcohol abuse severity. These results add to a growing body of evidence implicating omega-3 fatty acid deficiency as well as the OFC in the pathoaetiology of bipolar disorder.

  8. Arachidonic acid release and prostaglandin F(2alpha) formation induced by anandamide and capsaicin in PC12 cells.

    PubMed

    Someya, Akiyoshi; Horie, Syunji; Murayama, Toshihiko

    2002-08-23

    Anandamide, an endogenous agonist of cannabinoid receptors, activates various signal transduction pathways. Anandamide also activates vanilloid VR(1) receptor, which was a nonselective cation channel with high Ca(2+) permeability and had sensitivity to capsaicin, a pungent principle in hot pepper. The effects of anandamide and capsaicin on arachidonic acid metabolism in neuronal cells have not been well established. We examined the effects of anandamide and capsaicin on arachidonic acid release in rat pheochromocytoma PC12 cells. Both agents stimulated [3H]arachidonic acid release in a concentration-dependent manner from the prelabeled PC12 cells even in the absence of extracellular CaCl(2). The effect of anandamide was neither mimicked by an agonist nor inhibited by an antagonist for cannabinoid receptors. The effects of anandamide and capsaicin were inhibited by phospholipase A(2) inhibitors, but not by an antagonist for vanilloid VR(1) receptor. In PC12 cells preincubated with anandamide or capsaicin, [3H]arachidonic acid release was marked and both agents were no more effective. Co-addition of anandamide or capsaicin synergistically enhanced [3H]arachidonic acid release by mastoparan in the absence of CaCl(2). Anandamide stimulated prostaglandin F(2alpha) formation. These findings suggest that anandamide and capsaicin stimulated arachidonic acid metabolism in cannabinoid receptors- and vanilloid VR(1) receptor-independent manner in PC12 cells. The possible mechanisms are also discussed.

  9. Lipoxygenase-mediated pro-radical effect of melatonin via stimulation of arachidonic acid metabolism

    SciTech Connect

    Radogna, F.; Sestili, P.; Martinelli, C.; Paolillo, M.; Paternoster, L.; Albertini, M.C.; Accorsi, A.; Gualandi, G.; Ghibelli, L.

    2009-07-15

    We have shown that melatonin immediately and transiently stimulates intracellular free radical production on a set of leukocytes, possibly as a consequence of calmodulin binding. We show here that melatonin-induced ROS are produced by lipoxygenase (LOX), since they are prevented by a set of LOX inhibitors, and are accompanied by increase of the 5-LOX product 5-HETE. LOX activation is accompanied by strong liberation of AA; inhibition of Ca{sup 2+}-independent, but not Ca{sup 2+}-dependent, phospholipase A2 (PLA2), prevents both melatonin-induced arachidonic acid and ROS production, whereas LOX inhibition only prevents ROS, indicating that PLA2 is upstream with respect to LOX, as occurs in many signaling pathways. Chlorpromazine, an inhibitor of melatonin-calmodulin interaction, inhibits both ROS and arachidonic acid production, thus possibly placing calmodulin at the origin of a melatonin-induced pro-radical pathway. Interestingly, it is known that Ca{sup 2+}-independent PLA2 binds to calmodulin: our results are compatible with PLA2 being liberated by melatonin from a steady-state calmodulin sequestration, thus initiating an arachidonate signal transduction. These results delineate a novel molecular pathway through which melatonin may participate to the inflammatory response.

  10. Role of Lipoxygenase Metabolites of Arachidonic Acid in Enhanced Pulmonary Artery Contractions of Female Rabbits

    PubMed Central

    Pfister, Sandra L.

    2011-01-01

    Pulmonary arterial hypertension is characterized by elevated pulmonary artery pressure and vascular resistance. In women the incidence is 4 fold greater than that in men. Studies suggest sustained vasoconstriction is a factor in increased vascular resistance. Possible vasoconstrictor mediators include arachidonic acid-derived lipoxygenase metabolites. Our studies in rabbits showed enhanced endothelium-dependent contractions to arachidonic acid in pulmonary arteries from females compared to males. Because treatment with a non-specific lipoxygenase inhibitor reduced contractions in females but not males, the present study identified which lipoxygenase isoform contributes to sex-specific pulmonary artery vasoconstriction. 15- and 5- but not 12-lipoxygenase protein expression was greater in females. Basal and A23187-stimulated release of 15-, 5- and 12-hydroxyeicosatetraenoic acid from females and males was measured by liquid chromatography/mass spectrometry. Only 15-hydroxyeicosatetraenoic acid synthesis was greater in females compared to males under both basal and stimulated conditions. Vascular contractions to 15-hydroxyeicosatetraenoic acid were enhanced in females compared to males (maximal contraction; 44 ± 6% vs 25 ± 3%). The specific 15-lipoxygenase inhibitor PD146176 (12 μmol/L) decreased arachidonic acid-induced contractions in females (maximal contraction; 93 ± 4% vs 57 ± 10%). If male pulmonary arteries were incubated with estrogen (1 μmol/L, 18 hrs), protein expression of 15-lipoxygenase, and 15-hydroxyeicosatetraenoic acid production increased. Mechanisms to explain the increased incidence of pulmonary hypertension in women are not known. Results suggest the 15-lipoxygenase pathway is different between females and males and is regulated by estrogen. Understanding this novel sex-specific mechanism may provide insight into the increased incidence of pulmonary hypertension in females. PMID:21300669

  11. Regulation of an ATP-conductive large-conductance anion channel and swelling-induced ATP release by arachidonic acid

    PubMed Central

    Dutta, Amal K; Okada, Yasunobu; Sabirov, Ravshan Z

    2002-01-01

    Mouse mammary C127 cells responded to hypotonic stimulation with activation of the volume-dependent ATP-conductive large conductance (VDACL) anion channel and massive release of ATP. Arachidonic acid downregulated both VDACL currents and swelling-induced ATP release in the physiological concentration range with Kd of 4– 6 μm. The former effect observed in the whole-cell or excised patch mode was more prominent than the latter effect observed in intact cells. The arachidonate effects were direct and not mediated by downstream metabolic products, as evidenced by their insensitivity to inhibitors of arachidonate-metabolizing oxygenases, and by the observation that they were mimicked by cis-unsaturated fatty acids, which are not substrates for oxygenases. A membrane-impermeable analogue, arachidonyl coenzyme A was effective only from the cytosolic side of membrane patches suggesting that the binding site is localized intracellularly. Non-charged arachidonate analogues as well as trans-unsaturated and saturated fatty acids had no effect on VDACL currents and ATP release, indicating the importance of arachidonate's negative charge and specific hydrocarbon chain conformation in the inhibitory effect. VDACL anion channels were inhibited by arachidonic acid in two different ways: channel shutdown (Kd of 4– 5 μm) and reduced unitary conductance (Kd of 13–14 μm) without affecting voltage dependence of open probability. ATP4--conducting inward currents measured in the presence of 100 mm ATP in the bath were reversibly inhibited by arachidonic acid. Thus, we conclude that swelling-induced ATP release and its putative pathway, the VDACL anion channel, are under a negative control by intracellular arachidonic acid signalling in mammary C127 cells. PMID:12154180

  12. Individual variation and intraclass correlation in arachidonic acid and eicosapentaenoic acid in chicken muscle

    PubMed Central

    2010-01-01

    Chicken meat with reduced concentration of arachidonic acid (AA) and reduced ratio between omega-6 and omega-3 fatty acids has potential health benefits because a reduction in AA intake dampens prostanoid signaling, and the proportion between omega-6 and omega-3 fatty acids is too high in our diet. Analyses for fatty acid determination are expensive, and finding the optimal number of analyses to give reliable results is a challenge. The objective of the present study was i) to analyse the intraclass correlation of different fatty acids in five meat samples, of one gram each, within the same chicken thigh, and ii) to study individual variations in the concentrations of a range of fatty acids and the ratio between omega-6 and omega-3 fatty acid concentrations among fifteen chickens. Fifteen newly hatched broilers were fed a wheat-based diet containing 4% rapeseed oil and 1% linseed oil for three weeks. Five muscle samples from the mid location of the thigh of each chicken were analysed for fatty acid composition. The intraclass correlation (sample correlation within the same animal) was 0.85-0.98 for the ratios of total omega-6 to total omega-3 fatty acids and of AA to eicosapentaenoic acid (EPA). This indicates that when studying these fatty acid ratios, one sample of one gram per animal is sufficient. However, due to the high individual variation between chicken for these ratios, a relatively high number of animals (minimum 15) are required to obtain a sufficiently high power to reveal significant effects of experimental factors (e.g. feeding regimes). The present experiment resulted in meat with a favorable concentration ratio between omega-6 and omega-3 fatty acids. The AA concentration varied from 1.5 to 2.8 g/100 g total fatty acids in thigh muscle in the fifteen broilers, and the ratio between AA and EPA concentrations ranged from 2.3 to 3.9. These differences among the birds may be due to genetic variance that can be exploited by breeding for lower AA

  13. Phospholipase A2 and Arachidonic Acid in Alzheimer’s Disease

    PubMed Central

    Sanchez-Mejia, Rene O.; Mucke, Lennart

    2011-01-01

    Essential fatty acids (EFA) play a critical role in the brain and regulate many of the processes altered in Alzheimer’s disease (AD). Technical advances are allowing for the dissection of complex lipid pathways in normal and diseased states. Arachidonic acid (AA) and specific isoforms of phospholipase A2 (PLA2) appear to play critical mediator roles in amyloid-β (Aβ) - induced pathogenesis, leading to learning, memory, and behavioral impairments in mouse models of AD. These findings and ongoing research into lipid biology in AD and related disorders promise to reveal new pharmacological targets that may lead to better treatments for these devastating conditions. PMID:20553961

  14. Eicosapentaenoic acid (EPA) reduces cardiovascular events: relationship with the EPA/arachidonic acid ratio.

    PubMed

    Ohnishi, Haruo; Saito, Yasushi

    2013-01-01

    The clinical efficacy of fish oil and high-purity eicosapentaenoic acid ethyl ester (hp-EPA-E) for treating cardiovascular disease (CVD) has been reported. Fish oil contains saturated and monounsaturated fatty acids that have pharmacological effects opposite to those of ω3 fatty acids (ω3). Moreover, ω3, such as EPA and docosahexaenoic acid (DHA), do not necessarily have the same metabolic and biological actions. This has obscured the clinical efficacy of ω3. Recently, the Japan EPA Lipid Intervention Study (JELIS) of hp-EPA-E established the clinical efficacy of EPA for CVD, and higher levels of blood EPA, not DHA, were found to be associated with a lower incidence of major coronary events. A significant reduction in the risk of coronary events was observed when the ratio of EPA to arachidonic acid (AA) (EPA/AA) was > 0.75. Furthermore, the ratio of prostaglandin (PG) I3 and PGI2 to thromboxane A2 (TXA2) ([PGI2 + PGI3]/TXA2) was determined to have a linear relationship with the EPA/AA ratio as follows: (PGI2 + PGI3)/TXA2 =λ + π* (EPA/AA). Like PGI2, PGI3 not only inhibits platelet aggregation and vasoconstriction, but also is assumed to reduce cardiac ischemic injury and arteriosclerosis and promote angiogenesis. Thus, the effects of EPA in reducing the risk of CVD could be mediated by biological action of PGI3 in addition to hypotriglyceridemic action of EPA. Compared with DHA, EPA administration increases the EPA/AA ratio and the (PGI2 + PGI3)/TXA2 balance to a state that inhibits the onset and/or progression of CVD.

  15. Molecular Dynamics Simulations of Arachidonic Acid Complexes with COX-1 and COX-2

    PubMed Central

    Furse, Kristina E.; Pratt, Derek A.; Porter, Ned A.; Lybrand, Terry P.

    2008-01-01

    The cyclooxygenase (COX) enzymes are responsible for the committed step in prostaglandin biosynthesis, the generation of prostaglandin H2. As a result, these enzymes are pharmacologically important targets for non-steroidal anti-inflammatory drugs, such as aspirin and newer COX-2 selective inhibitors. The cyclooxygenases are functional homodimers, and each subunit contains both a cyclooxygenase and a peroxidase active site. These enzymes are quite interesting mechanistically, as the conversion of arachidonic acid to prostaglandin H2 requires two oxygenation and two cyclization reactions, resulting in the formation of five new chiral centers with nearly absolute regio- and stereochemical fidelity. We have used molecular dynamics (MD) simulations to investigate the equilibrium behavior of both COX-1 and COX-2 enzyme isoforms with bound arachidonate. These simulations were compared with reference simulations of arachidonate in solution to explore the effect of enzyme on substrate conformation and positioning in the active site. The simulations suggest that the substrate has greater conformational freedom in the COX-2 active site, consistent with the larger COX-2 active site volume observed in X-ray crystal structures. The simulations reveal different conformational behavior for arachidonate in each subunit over the course of extended equilibrium MD simulations. The simulations also provide detailed information for several protein channels that might be important for oxygen and water transport to or from active sites, or for intermediate trafficking between the cyclooxygenase and peroxidase active sites. The detailed comparisons for COX-1 versus COX-2 active site structural fluctuations may also provide useful information for design of new isozyme-selective inhibitors. PMID:16519514

  16. Arachidonic and eicosapentaenoic acids in tissues of the firefly, Photinus pyralis (Insecta: Coleoptera).

    PubMed

    Nor Aliza, A R; Bedick, J C; Rana, R L; Tunaz, H; Hoback, W W; Stanley, D W

    2001-02-01

    We report on the presence of high proportions of arachidonic acid (20:4n-6) and eicosapentaenoic acid (20:5n-3) in the tissue lipids of adult fireflies, Photinus pyralis. Arachidonic acid typically occurs in very small proportions in phospholipids (PLs) of terrestrial insects, ranging from no more than traces to less than 1% of PL fatty acids, while 20:5n-3 is often missing entirely from insect lipids. Contrarily, 20:4n-6 made up approximately 21% of the PL fatty acids prepared from whole males and females, and from heads and thoraces prepared from males. Proportions of 20:4n-6 associated with PLs varied among tissues, including approximately 8% for male gut epithelia, 13% for testes, and approximately 25% for light organs and body fat from males. Substantial proportions of 20:5n-3 were also associated with PLs prepared from male firefly tissues, including 5% for body fat and 8% for light organs. Because 20:4n-6 and 20:5n-3 are precursors for biosynthesis of prostaglandins and other eicosanoids, we considered the possibility that firefly tissues might produce eicosanoids at exceptionally high rates. Preliminary experiments indicated otherwise. Hence, fireflies are peculiar among terrestrial insects with respect to maintaining high proportions of PL 20:4n-6 and 20:5n-3.

  17. Liquid human milk fortifier significantly improves docosahexaenoic and arachidonic acid status in preterm infants.

    PubMed

    Berseth, C L; Harris, C L; Wampler, J L; Hoffman, D R; Diersen-Schade, D A

    2014-09-01

    We report the fatty acid composition of mother׳s own human milk from one of the largest US cohorts of lactating mothers of preterm infants. Milk fatty acid data were used as a proxy for intake at enrollment in infants (n=150) who received human milk with a powder human milk fortifier (HMF; Control) or liquid HMF [LHMF; provided additional 12mg docosahexaenoic acid (DHA), 20mg arachidonic acid (ARA)/100mL human milk]. Mothers provided milk samples (n=129) and reported maternal DHA consumption (n=128). Infant blood samples were drawn at study completion (Study Day 28). Human milk and infant PPL fatty acids were analyzed using capillary column gas chromatography. DHA and ARA were within ranges previously published for US term and preterm human milk. Compared to Control HMF (providing no DHA or ARA), human milk fortified with LHMF significantly increased infant PPL DHA and ARA and improved preterm infant DHA and ARA status.

  18. Arachidonate metabolism in bovine gallbladder muscle

    SciTech Connect

    Nakano, M.; Hidaka, T.; Ueta, T.; Ogura, R.

    1983-04-01

    Incubation of (1-/sup 14/C)arachidonic acid (AA) with homogenates of bovine gallbladder muscle generated a large amount of radioactive material having the chromatographic mobility of 6-keto-PGF1 alpha (stable product of PGI2) and smaller amounts of products that comigrated with PGF2 alpha PGE2. Formation of these products was inhibited by the cyclooxygenase inhibitor indomethacin. The major radioactive product identified by thin-layer chromatographic mobility and by gas chromatography - mass spectrometric analysis was found to be 6-keto-PGF1 alpha. The quantitative metabolic pattern of (1-/sup 14/C)PGH2 was virtually identical to that of (1-/sup 14/C)AA. Incubation of arachidonic acid with slices of bovine gallbladder muscle released labile anti-aggregatory material in the medium, which was inhibited by aspirin or 15-hydroperoxy-AA. These results indicate that bovine gallbladder muscle has a considerable enzymatic capacity to produce PGI2 from arachidonic acid.

  19. Evaluation of Bioequivalency and Toxicological Effects of Three Sources of Arachidonic Acid (ARA) in Domestic Piglets

    PubMed Central

    Tyburczy, Cynthia; Brenna, Margaret E.; DeMari, Joseph A.; Kothapalli, Kumar S. D.; Blank, Bryant S.; Valentine, Helen; McDonough, Sean P.; Banavara, Dattatreya; Diersen-Schade, Deborah A.; Brenna, J. Thomas

    2011-01-01

    Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are routinely added to infant formula to support growth and development. We evaluated the bioequivalence and safety of three ARA-rich oils for potential use in infant formula using the neonatal pig model. The primary outcome for bioequivalence was brain accretion of ARA and DHA. Days 3 to 22 of age, domestic pigs fed one of three formulas, each containing ARA at ~0.64% and DHA at ~0.34% total fatty acids (FA). Control diet ARA was provided by ARASCO® and all diets had DHA from DHASCO® (Martek Biosciences Corp., Columbia, MD). The experimental diets a1 and a2 provided ARA from Refined Arachidonic acid-rich Oil (RAO; Cargill, Inc., Wuhan, China) and SUNTGA40S (Nissui, Nippon Suisan Kaisha, Ltd., Tokyo, Japan), respectively. Formula intake and growth were similar across all diets, and ARA was bioequivalent across treatments in the brain, retina, heart, liver and day 21 RBC. DHA levels in the brain, retina and heart were unaffected by diet. Liver sections, clinical chemistry, and hematological parameters were normal. We conclude that RAO and SUNTGA40S, when added to formula to supply ~0.64% ARA are safe and nutritionally bioequivalent to ARASCO in domestic piglets. PMID:21722692

  20. Physiological inhibitory effect of ocs in arachidonic acid-rich Parietochloris incisa (trebouxiophyceae, chlorophyta)

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Guo; Zhang, Cheng-Wu; Cohen, Zvi; Richmond, Amos

    2002-09-01

    Parietochloris incisa is an arachidonic acid-rich snow green alga. The main physiological profiles, such as ash free dry weight (AFDW), chlorophyll, carotenoid, protein and total fatty acids (TFA), in this alga exposed to old culture supernatant (OCS) at the decline phase or its crude ethyl acetate extracts (CEAE) were investigated by using tubular photobioreactors of different diameters. Results showed that both OCS and CEAE had strong inhibitory effect on the above physiological parameters. The longer the culture was exposed to OCS and the more CEAE were added into the algal culture, the more the above physiological properties were inhibited. Arachidonic acid (AA), the dominant component of fatty acids in this alga, was also seriously inhibited with respect to total TFA, AFDW of cell mass, or culture volume, due to a probable reduction of enzymes activities catalyzing chain elongation from C18; 1ω9 to AA. These results incontestably evidenced that some CEAE dissolving substances existing in OCS. like auto-inhibitors, inhibited P. incisa growth through feedback. Hence, any efficient removal of auto-inhibitors from algal culture to decrease their bioactivity could be good for maximal production of desired products like AA.

  1. Mechanism of enhanced fibroblast arachidonic acid metabolism by mononuclear cell factor.

    PubMed Central

    Whiteley, P J; Needleman, P

    1984-01-01

    Chronic inflammation is associated with an infiltration of mononuclear cells, fibroblast proliferation, and elevated levels of prostaglandin (PG) E2. Mononuclear cell conditioned factor (MNCF) medium (5%) stimulated a 100-fold increase in basal human dermal fibroblast PGE2 release over 48 h as compared with fibroblasts that were incubated with control medium (conditioned medium prepared without cells). The MNCF-induced PGE2 production was suppressed by protein synthesis inhibitors. Fibroblasts pretreated with control medium released PGE2 only modestly in response to 1 nM bradykinin for 1 h (basal, 50 +/- 7 pg PGE2/micrograms protein; stimulated, 104 +/- 12 pg PGE2/micrograms protein), whereas cells that had been pretreated with MNCF showed a greatly facilitated bradykinin-induced release of PGE2. (basal, 297 +/- 59 pg PGE2/micrograms protein; stimulated, 866 +/- 85 pg PGE2/micrograms protein). The exaggerated agonist response is not specific for bradykinin because platelet-derived growth factor elicits a similar response. Exogenous arachidonic acid conversion to PGE2 was also facilitated (two- to threefold) by MNCF pretreatment as compared with control. Both the enhanced agonist-stimulated and exogenous arachidonic acid-induced PGE2 release from the MNCF pretreated cells were inhibited by actinomyin D or cycloheximide. A kinetic study of microsomal cyclooxygenase prepared from fibroblasts pretreated with MNCF showed a threefold increase in the maximum velocity (Vmax) but the same Michaelis constant (Km) as control-treated cells. This augmented arachidonic acid metabolism and subsequent enhanced PGE2 production may play an important role in macrophage-fibroblast interactions at sites of inflammation. PMID:6439745

  2. The influence of dietary docosahexaenoic acid and arachidonic acid on central nervous system polyunsaturated fatty acid composition.

    PubMed

    Brenna, J Thomas; Diau, Guan-Yeu

    2007-01-01

    Numerous studies on perinatal long-chain polyunsaturated fatty acid nutrition have clarified the influence of dietary docosahexaenoic acid (DHA) and arachidonic acid (ARA) on central nervous system PUFA concentrations. In humans, omnivorous primates, and piglets, DHA and ARA plasma and red blood cells concentrations rise with dietary preformed DHA and ARA. Brain and retina DHA are responsive to diet while ARA is not. DHA is at highest concentration in cells and tissues associated with high energy consumption, consistent with high DHA levels in mitochondria and synaptosomes. DHA is a substrate for docosanoids, signaling compounds of intense current interest. The high concentration in tissues with high rates of oxidative metabolism may be explained by a critical role related to oxidative metabolism.

  3. The Influence of Dietary Docosahexaenoic Acid and Arachidonic Acid on Central Nervous System Polyunsaturated Fatty Acid Composition

    PubMed Central

    Brenna, J. Thomas; Diau, Guan-Yeu

    2007-01-01

    Numerous studies on perinatal long chain polyunsaturated fatty acid nutrition have clarified the influence of dietary docosahexaenoic acid (DHA) and arachidonic acid (ARA) on central nervous system PUFA concentrations. In humans, omnivorous primates, and piglets, DHA and ARA plasma and red blood cells concentrations rise with dietary preformed DHA and ARA. Brain and retina DHA are responsive to diet while ARA is not. DHA is at highest concentration cells and tissues associated with high energy consumption, consistent with high DHA levels in mitochondria and synaptosomes. DHA is a substrate for docosanoids, signaling compounds of intense current interest. The high concentration in tissues with high rates of oxidative metabolism may be explained by a critical role related to oxidative metabolism. PMID:18023566

  4. Arachidonic acid activates release of calcium ions from reticulum via ryanodine receptor channels in C2C12 skeletal myotubes.

    PubMed

    Muslikhov, E R; Sukhanova, I F; Avdonin, P V

    2014-05-01

    Arachidonic acid causes an increase in free cytoplasmic calcium concentration ([Ca2+]i) in differentiated skeletal multinucleated myotubes C2C12 and does not induce calcium response in C2C12 myoblasts. The same reaction of myotubes to arachidonic acid is observed in Ca2+-free medium. This indicates that arachidonic acid induces release of calcium ions from intracellular stores. The blocker of ryanodine receptor channels of sarcoplasmic reticulum dantrolene (20 µM) inhibits this effect by 68.7 ± 6.3% (p < 0.001). The inhibitor of two-pore calcium channels of endolysosomal vesicles trans-NED19 (10 µM) decreases the response to arachidonic acid by 35.8 ± 5.4% (p < 0.05). The phospholipase C inhibitor U73122 (10 µM) has no effect. These data indicate the involvement of ryanodine receptor calcium channels of sarcoplasmic reticulum in [Ca2+]i elevation in skeletal myotubes caused by arachidonic acid and possible participation of two-pore calcium channels from endolysosomal vesicles in this process.

  5. Food Polyphenol Apigenin Inhibits the Cytochrome P450 Monoxygenase Branch of the Arachidonic Acid Cascade.

    PubMed

    Steuck, Maryvonne; Hellhake, Stefan; Schebb, Nils Helge

    2016-11-30

    The product of cytochrome P450 monooxygenase (P450) ω-hydroxylation of arachidonic acid (AA), 20- hydroxyeicosatetraenoic acid (HETE), is a potent vasoconstrictor. Utilizing microsomes as well as individual CYP4 isoforms we demonstrate here that flavonoids can block 20-HETE formation. Apigenin inhibits CYP4F2 with an IC50 value of 4.6 μM and 20-HETE formation in human liver and kidney microsomes at 2.4-9.8 μM. Interestingly, the structurally similar naringenin shows no relevant effect on the formation of 20-HETE. Based on these in vitro data, it is impossible to evaluate if a relevant blockade of 20-HETE formation can result in humans from intake of polyphenols with the diet. However, the potency of apigenin is comparable to those of P450 inhibitors such as ketoconazole. Moreover, an IC50 value in the micromolar range is also described for the inhibition of CYP-mediated drug metabolism leading to food-drug interactions. The modulation of the arachidonic acid cascade by food polyphenols therefore warrants further investigation.

  6. Omega-3 PUFAs Lower the Propensity for Arachidonic Acid Cascade Overreactions

    PubMed Central

    Lands, Bill

    2015-01-01

    A productive view of the benefits from omega-3 (n-3) nutrients is that the dietary essential omega-6 (n-6) linoleic acid has a very narrow therapeutic window which is widened by n-3 nutrients. The benefit from moderate physiological actions of the arachidonic acid cascade can easily shift to harm from excessive pathophysiological actions. Recognizing the factors that predispose the cascade to an unwanted overactivity gives a rational approach for arranging beneficial interactions between the n-3 and n-6 essential nutrients that are initial components of the cascade. Much detailed evidence for harmful cascade actions was collected by pharmaceutical companies as they developed drugs to decrease those actions. A remaining challenge is to understand the factors that predispose the cascade toward unwanted outcomes and create the need for therapeutic interventions. Such understanding involves recognizing the similar dynamics for dietary n-3 and n-6 nutrients in forming the immediate precursors of the cascade plus the more vigorous actions of the n-6 precursor, arachidonic acid, in forming potent mediators that amplify unwanted cascade outcomes. Tools have been developed to aid deliberate day-to-day quantitative management of the propensity for cascade overactivity in ways that can decrease the need for drug treatments. PMID:26301244

  7. Biosynthesis, biological effects, and receptors of hydroxyeicosatetraenoic acids (HETEs) and oxoeicosatetraenoic acids (oxo-ETEs) derived from arachidonic acid.

    PubMed

    Powell, William S; Rokach, Joshua

    2015-04-01

    Arachidonic acid can be oxygenated by a variety of different enzymes, including lipoxygenases, cyclooxygenases, and cytochrome P450s, and can be converted to a complex mixture of oxygenated products as a result of lipid peroxidation. The initial products in these reactions are hydroperoxyeicosatetraenoic acids (HpETEs) and hydroxyeicosatetraenoic acids (HETEs). Oxoeicosatetraenoic acids (oxo-ETEs) can be formed by the actions of various dehydrogenases on HETEs or by dehydration of HpETEs. Although a large number of different HETEs and oxo-ETEs have been identified, this review will focus principally on 5-oxo-ETE, 5S-HETE, 12S-HETE, and 15S-HETE. Other related arachidonic acid metabolites will also be discussed in less detail. 5-Oxo-ETE is synthesized by oxidation of the 5-lipoxygenase product 5S-HETE by the selective enzyme, 5-hydroxyeicosanoid dehydrogenase. It actions are mediated by the selective OXE receptor, which is highly expressed on eosinophils, suggesting that it may be important in eosinophilic diseases such as asthma. 5-Oxo-ETE also appears to stimulate tumor cell proliferation and may also be involved in cancer. Highly selective and potent OXE receptor antagonists have recently become available and could help to clarify its pathophysiological role. The 12-lipoxygenase product 12S-HETE acts by the GPR31 receptor and promotes tumor cell proliferation and metastasis and could therefore be a promising target in cancer therapy. It may also be involved as a proinflammatory mediator in diabetes. In contrast, 15S-HETE may have a protective effect in cancer. In addition to GPCRs, higher concentration of HETEs and oxo-ETEs can activate peroxisome proliferator-activated receptors (PPARs) and could potentially regulate a variety of processes by this mechanism. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".

  8. Kinetics of uptake and distribution of arachidonic acid by rat alveolar macrophages

    SciTech Connect

    Robison, T.W.; Duncan, D.P.; Forman, H.J.

    1988-10-01

    The time course of uptake and distribution of /sup 3/H-arachidonic acid (/sup 3/H-AA) into rat alveolar macrophage phospholipid pools was examined. Macrophages incubated with exogenous /sup 3/H-AA in RPMI-1640 containing 0.1% bovine serum albumin (BSA), incorporated this radiolabel into phosphatidylcholine and phosphatidylinositol (PI) with plateaus reached within 2 to 4 hours, which remained relatively constant for up to 18 hours. Incorporation of /sup 3/H-AA into phosphatidylethanolamine was small, but continued to increase for 14 hours. Analysis of phosphate content in phospholipid pools revealed that treatment with exogenous 5 nM arachidonic acid had no effect upon pool sizes, but there was a selective incorporation of /sup 3/H-AA into PI. Cells were incubated with /sup 3/H-AA in RPMI alone or medium containing either 0.2% lactalbumin, fetal calf serum at variable concentrations, 10% Nu Serum, or 0.1% BSA. Incubation of macrophages with /sup 3/H-AA in RPMI alone or containing 0.2% lactalbumin, resulted in approximately 70% of the radiolabel taken up by the cells being incorporated into triglyceride. The addition of BSA to RPMI-1640 medium was found to facilitate selective uptake of /sup 3/H-AA into phospholipids. Approximately 70% of incorporated /sup 3/H-AA was releasable through the action of exogenous phospholipase A2.

  9. Cytosolic phospholipase A2 is coupled to hormonally regulated release of arachidonic acid.

    PubMed Central

    Lin, L L; Lin, A Y; Knopf, J L

    1992-01-01

    Cytosolic phospholipase A2 (cPLA2) binds to natural membrane vesicles in a Ca(2+)-dependent fashion, resulting in the selective release of arachidonic acid, thus implicating cPLA2 in the hormonally regulated production of eicosanoids. Here we report that the treatment of Chinese hamster ovary (CHO) cells overexpressing cPLA2 with ATP or thrombin resulted in an increased release of arachidonic acid as compared with parental CHO cells, demonstrating the hormonal coupling of cPLA2. In contrast, CHO cells overexpressing a secreted form of mammalian PLA2 (sPLA2-II) failed to show any increased hormonal responsiveness. Interestingly, we have noted that the activation of cPLA2 with a wide variety of agents stimulates the phosphorylation of cPLA2 on serine residues. Pretreatment of cells with staurosporin blocked the ATP-mediated phosphorylation of cPLA2 and strongly inhibited the activation of the enzyme. Increased cPLA2 activity was also observed in lysates prepared from ATP-treated cells and was sensitive to phosphatase treatment. These results suggest that in addition to Ca2+, the phosphorylation of cPLA2 plays an important role in the agonist-induced activation of cPLA2. Images PMID:1631101

  10. Endocannabinoid system modulates relapse to methamphetamine seeking: possible mediation by the arachidonic acid cascade.

    PubMed

    Anggadiredja, Kusnandar; Nakamichi, Masanori; Hiranita, Takato; Tanaka, Hiroyuki; Shoyama, Yukihiro; Watanabe, Shigenori; Yamamoto, Tsuneyuki

    2004-08-01

    We clarified the modulating action of the endocannabinoid system, and its possible mediation by the arachidonic acid cascade, on the reinstatement of methamphetamine (METH)-seeking behavior, using the intravenous self-administration paradigm in rats. Following 12 days of self-administration of METH, the replacement of METH with saline resulted in a gradual decrease in lever press responses (extinction). Under extinction conditions, METH-priming or re-exposure to cues previously paired with METH infusion markedly increased the responses (reinstatement of drug-seeking). The cannabinoid CB1 receptor antagonist, SR141716A, blocked this behavior. Although the cannabinoid agonist, Delta8-tetrahydrocannabinol (THC), had no effects by itself, coadministration of the agonist and METH at small doses reinstated the drug-seeking behavior. THC attenuated the effects of the reinstatement-inducing dose of METH, but enhanced the effect of cues. Either given repeatedly during the extinction or singly, 24 h before the first METH-priming or cues challenge, THC suppressed the reinstatement. In another set of experiments, we found that diclofenac, a cyclooxygenase inhibitor, also attenuated the reinstatement induced by exposure to cues or drug-priming. These results suggest that the endocannabinoid system, through possible mediation by the arachidonic acid cascade, serves as a modulator of the reinstating effects of METH-priming and cues. Extending the current view on the treatment of drug dependence, these results indicate that endocannabinoid-activating substances as well as cyclooxygenase inhibitors may be promising as antirelapse agents.

  11. The effect of etretinate on the cyclo-oxygenase and lipoxygenase products of arachidonic acid metabolism in psoriatic skin.

    PubMed Central

    Wong, E; Barr, R M; Brain, S D; Greaves, M W; Olins, L A; Mallet, A I

    1984-01-01

    Eight psoriatic patients were treated with etretinate (50 mg daily) for 6 weeks. Skin chamber exudates from involved and uninvolved skin were assayed for arachidonic acid, 12-HETE, PGE2 and for neutrophil chemokinetic activity co-chromatographing with leukotriene B4, before and at weekly intervals during therapy. Pre-treatment concentrations of arachidonic acid, 12-HETE and leukotriene B4-like chemokinetic activity but not of PGE2 were elevated in involved skin when compared to uninvolved skin. The concentrations of arachidonic acid and 12-HETE declined during therapy but changes in PGE2 were minimal. LTB4-like activity was detectable in involved skin both before and after etretinate treatment. Clinically, scaling and infiltration improved but erythema was still evident. PMID:6091710

  12. Arachidonic acid-induced Ca2+ sensitization of smooth muscle contraction through activation of Rho-kinase.

    PubMed

    Araki, S; Ito, M; Kureishi, Y; Feng, J; Machida, H; Isaka, N; Amano, M; Kaibuchi, K; Hartshorne, D J; Nakano, T

    2001-02-01

    Arachidonic acid activates isolated Rho-kinase and contracts permeabilized smooth muscle fibres. Various assays were carried out to examine the mechanism of this activation. Native Rho-kinase was activated 5-6 times by arachidonic acid but an N-terminal, constitutively-active fragment of Rho-kinase, expressed as a glutathione-S-transferase (GST) fusion protein and including the catalytic subunit (GST-Rho-kinase-CAT), was not. GST-Rho-kinase-CAT was inhibited by a C-terminal fragment of Rho-kinase and arachidonic acid removed this inhibition. These results suggest that the C-terminal part of Rho-kinase, containing the RhoA binding site and the pleckstrin homology domain, acts as an autoinhibitor. It is suggested further that activation by arachidonic acid is due to its binding to the autoinhibitory region and subsequent release from the catalytic site. Arachidonic acid, at concentrations greater than 30 microM, increases force in alpha-toxin-permeabilized femoral artery but not in Triton X-100-skinned fibres. The content of Rho-kinase in the latter was lower than in alpha-toxin-treated or intact fibres. The arachidonic acid-induced contraction was not observed at a pCa above 8.0 and was inhibited by Y-27632 and wortmannin, inhibitors of Rho-kinase and myosin light-chain kinase (MLCK), respectively. The activation of Rho-kinase and subsequent phosphorylation of the myosin phosphatase target subunit inhibits myosin phosphatase and increases myosin phosphorylation.

  13. Protein tyrosine phosphatases regulate arachidonic acid release, StAR induction and steroidogenesis acting on a hormone-dependent arachidonic acid-preferring acyl-CoA synthetase.

    PubMed

    Cano, Florencia; Poderoso, Cecilia; Cornejo Maciel, Fabiana; Castilla, Rocío; Maloberti, Paula; Castillo, Fernanda; Neuman, Isabel; Paz, Cristina; Podestá, Ernesto J

    2006-06-01

    The activation of the rate-limiting step in steroid biosynthesis, that is the transport of cholesterol into the mitochondria, is dependent on PKA-mediated events triggered by hormones like ACTH and LH. Two of such events are the protein tyrosine dephosphorylation mediated by protein tyrosine phosphatases (PTPs) and the release of arachidonic acid (AA) mediated by two enzymes, ACS4 (acyl-CoA synthetase 4) and Acot2 (mitochondrial thioesterase). ACTH and LH regulate the activity of PTPs and Acot2 and promote the induction of ACS4. Here we analyzed the involvement of PTPs on the expression of ACS4. We found that two PTP inhibitors, acting through different mechanisms, are both able to abrogate the hormonal effect on ACS4 induction. PTP inhibitors also reduce the effect of cAMP on steroidogenesis and on the level of StAR protein, which facilitates the access of cholesterol into the mitochondria. Moreover, our results indicate that exogenous AA is able to overcome the inhibition produced by PTP inhibitors on StAR protein level and steroidogenesis. Then, here we describe a link between PTP activity and AA release, since ACS4 induction is under the control of PTP activity, being a key event for AA release, StAR induction and steroidogenesis.

  14. Acute doxorubicin cardiotoxicity alters cardiac cytochrome P450 expression and arachidonic acid metabolism in rats

    SciTech Connect

    Zordoky, Beshay N.M.; Anwar-Mohamed, Anwar; Aboutabl, Mona E.

    2010-01-01

    Doxorubicin (DOX) is a potent anti-neoplastic antibiotic used to treat a variety of malignancies; however, its use is limited by dose-dependent cardiotoxicity. Moreover, there is a strong correlation between cytochrome P450 (CYP)-mediated arachidonic acid metabolites and the pathogenesis of many cardiovascular diseases. Therefore, in the current study, we have investigated the effect of acute DOX toxicity on the expression of several CYP enzymes and their associated arachidonic acid metabolites in the heart of male Sprague-Dawley rats. Acute DOX toxicity was induced by a single intraperitoneal injection of 15 mg/kg of the drug. Our results showed that DOX treatment for 24 h caused a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A1, CYP4A3, CYP4F1, CYP4F4, and EPHX2 gene expression in the heart of DOX-treated rats as compared to the control. Similarly, there was a significant induction of CYP1A1, CYP1B1, CYP2C11, CYP2J3, CYP4A, and sEH proteins after 24 h of DOX administration. In the heart microsomes, acute DOX toxicity significantly increased the formation of 20-HETE which is consistent with the induction of the major CYP omega-hydroxylases: CYP4A1, CYP4A3, CYP4F1, and CYP4F4. On the other hand, the formation of 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids (EETs) was significantly reduced, whereas the formation of their corresponding dihydroxyeicosatrienoic acids was significantly increased. The decrease in the cardioprotective EETs can be attributed to the increase of sEH activity parallel to the induction of the EPHX2 gene expression in the heart of DOX-treated rats. In conclusion, acute DOX toxicity alters the expression of several CYP and sEH enzymes with a consequent alteration in arachidonic acid metabolism. These results may represent a novel mechanism by which this drug causes progressive cardiotoxicity.

  15. Significance of Brain Tissue Oxygenation and the Arachidonic Acid Cascade in Stroke

    PubMed Central

    Rink, Cameron

    2011-01-01

    Abstract The significance of the hypoxia component of stroke injury is highlighted by hypermetabolic brain tissue enriched with arachidonic acid (AA), a 22:6n-3 polyunsaturated fatty acid. In an ischemic stroke environment in which cerebral blood flow is arrested, oxygen-starved brain tissue initiates the rapid cleavage of AA from the membrane phospholipid bilayer. Once free, AA undergoes both enzyme-independent and enzyme-mediated oxidative metabolism, resulting in the formation of number of biologically active metabolites which themselves contribute to pathological stroke outcomes. This review is intended to examine two divergent roles of molecular dioxygen in brain tissue as (1) a substrate for life-sustaining homeostatic metabolism of glucose and (2) a substrate for pathogenic metabolism of AA under conditions of stroke. Recent developments in research concerning supplemental oxygen therapy as an intervention to correct the hypoxic component of stroke injury are discussed. Antioxid. Redox Signal. 14, 1889–1903. PMID:20673202

  16. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature

    PubMed Central

    Norambuena, Fernando; Morais, Sofia; Emery, James A.; Turchini, Giovanni M.

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad–time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  17. Dietary docosahexaenoic acid but not arachidonic acid influences central nervous system fatty acid status in baboon neonates.

    PubMed

    Hsieh, Andrea T; Brenna, J Thomas

    2009-01-01

    The influence of dietary docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6) on infant central nervous system (CNS) composition has implications for neural development, including vision, cognition, and motor function. We consider here combined results of three published studies of DHA/AA-containing formulas and breastfeeding to evaluate the CNS tissue response of baboon neonates with varied concentration and duration of DHA/AA consumption [G.Y. Diau, A.T. Hsieh, E.A. Sarkadi-Nagy, V. Wijendran, P.W. Nathanielsz, J.T. Brenna, The influence of long chain polyunsaturate supplementation on docosahexaenoic acid and arachidonic acid in baboon neonate central nervous system, BMC Med. 3 (2005) 11; A.T. Hsieh, J.C. Anthony, D.A. Diersen-Schade, et al., The influence of moderate and high dietary long chain polyunsaturated fatty acids (LCPUFA) on baboon neonate tissue fatty acids, Pediatr. Res. 61 (2007) 537-45; E. Sarkadi-Nagy, V. Wijendran, G.Y. Diau, et al., The influence of prematurity and long chain polyunsaturate supplementation in 4-week adjusted age baboon neonate brain and related tissues, Pediatr. Res. 54 (2003) 244-252]. A total of 43 neonates born spontaneously at term, or preterm by Cesarean section, consumed diets with DHA-AA (%w/w) at several levels: none (0,0), moderate (0.3, 0.6), or high (>0.6, 0.67 or 1.2). CNS fatty acids were analyzed at 4 and 12 weeks postpartum for term baboons and 7.5 weeks for preterm neonates. CNS DHA was consistently greater by 5-30% in neonates consuming DHA and nearer 30% for cortex. In contrast, CNS AA was unaffected by dietary AA and decreased in all structures with age. Dietary DHA consistently supports greater CNS DHA and maintenance of cortex DHA concentration with feeding duration, while CNS AA is not related to dietary supply. These data on structure-specific LCPUFA accretion may provide insight into neural mechanisms responsible for suboptimal functional outcomes in infants consuming diets that do not

  18. Absorption and lymphatic transport of exogenous and endogenous arachidonic and linoleic acid in the rat

    SciTech Connect

    Nilsson, A.; Landin, B.; Jensen, E.; Akesson, B.

    1987-06-01

    (/sup 3/H)Arachidonic (20:4) and (/sup 14/C)linoleic acid (18:2) were fed to thoracic duct-cannulated rats in test meals of either tracers alone, cream, Intralipid, pure arachidonic acid, or pure linoleic acid. Less (/sup 3/H)20:4 than (/sup 14/C)18:2 was recovered in chyle during the first 5 h. After cream feeding, the proportion of radioactivity found in phospholipids was high and increased during the first 3 h. After the meal 61 +/- 6% of the /sup 3/H and 57 +/- 10% of the /sup 14/C was in phosphatidylcholine, and 11 +/- 3% of the /sup 3/H and 3.0 +/- 4% of the /sup 14/C was in phosphatidylethanolamine. Changing the fat vehicle to Intralipid or pure 18:2 decreased the proportion of label in the phospholipds and increased the /sup 3/H and /sup 14/C radioactivity in the triacylglycerol fraction, the distribution of /sup 14/C radioactivity in the triacylglycerol fraction, the distribution of /sup 14/C being influenced more than that of /sup 3/H. After feeding the tracers in 200 ..mu..l of pure 20:4, >90% of both isotopes was in triacylglycerol. During fasting, triacylglycerol transported 56% (0.7 ..mu..mol/h), phosphatidylethanolamine transported 10% (0.1 ..mu..mol/h) of the 20:4 mass. After cream or Intralipid feeding, the output of 20:4-containing phosphatidylcholine and phosphatidylethanolamine increased 2.1- to 2.8-fold, whereas the transport of 20:4 with triacylglycerol remained constant. Phospholipids thus became the predominant transport form for 20:4. After feeding 200 ..mu..l of 20:4, the intestine produced, however, 20:4-rich triacylglycerols that transported 80% of the chyle 20:4.

  19. Linoleic acid supplementation results in increased arachidonic acid and eicosanoid production in CF airway cells and in cftr−/− transgenic mice

    PubMed Central

    Zaman, Munir M.; Martin, Camilia R.; Andersson, Charlotte; Bhutta, Abdul Q.; Cluette-Brown, Joanne E.; Laposata, Michael

    2010-01-01

    Cystic fibrosis (CF) patients display a fatty acid imbalance characterized by low linoleic acid levels and variable changes in arachidonic acid. This led to the recommendation that CF patients consume a high-fat diet containing >6% linoleic acid. We hypothesized that increased conversion of linoleic acid to arachidonic acid in CF leads to increased levels of arachidonate-derived proinflammatory metabolites and that this process is exacerbated by increasing linoleic acid levels in the diet. To test this hypothesis, we determined the effect of linoleic acid supplementation on downstream proinflammatory biomarkers in two CF models: 1) in vitro cell culture model using 16HBE14o− sense [wild-type (WT)] and antisense (CF) human airway epithelial cells; and 2) in an in vivo model using cftr−/− transgenic mice. Fatty acids were analyzed by gas chromatography-mass spectrometry (GC/MS), and IL-8 and eicosanoids were measured by ELISA. Neutrophils were quantified in bronchoalveolar lavage fluid from knockout mice following linoleic acid supplementation and exposure to aerosolized Pseudomonas LPS. Linoleic acid supplementation increased arachidonic acid levels in CF but not WT cells. IL-8, PGE2, and PGF2α secretion were increased in CF compared with WT cells, with a further increase following linoleic acid supplementation. cftr−/− Mice supplemented with 100 mg of linoleic acid had increased arachidonic acid levels in lung tissue associated with increased neutrophil infiltration into the airway compared with control mice. These findings support the hypothesis that increasing linoleic acid levels in the setting of loss of cystic fibrosis transmembrane conductance regulator (CFTR) function leads to increased arachidonic acid levels and proinflammatory mediators. PMID:20656894

  20. Neutrophil chemotaxis and arachidonic acid metabolism are not linked: evidence from metal ion probe studies

    SciTech Connect

    Turner, S.R.; Turner, R.A.; Smith, D.M.; Johnson, J.A.

    1986-03-05

    Heavy metal ions can inhibit arachidonic acid (AA) metabolism protect against ionophore cytotoxicity (ibid) and inhibit neutrophil chemotaxis. In this study they used Au/sup 3 +/, Zn/sup 2 +/, Cr/sup 3 +/, Mn/sup 2 +/ and Cu/sup 2 +/ as probes of the interrelationships among AA metabolism, ionophore-mediated cytotoxicity, and chemotaxis. Phospholipid deacylation was measured in ionophore-treated cells prelabeled with /sup 3/H-AA. Eicosanoid release from ionophore-treated cells was monitored by radioimmunoassay. Cytoprotection was quantitated as ability to exclude trypan blue. Chemotaxis toward f-met-leu-phe was measured by leading front analysis. The results imply that metal ions attenuate ionophore cytotoxicity by blocking phospholipid deacylation and eicosanoid release. In contrast to previous reports, no correlation between AA metabolism and chemotaxis was demonstrated, suggesting that these 2 processes are not linked.

  1. Arachidonic Acid Derivatives and Their Role in Peripheral Nerve Degeneration and Regeneration

    PubMed Central

    Camara-Lemarroy, Carlos Rodrigo; Gonzalez-Moreno, Emmanuel Irineo; Guzman-de la Garza, Francisco Javier; Fernandez-Garza, Nancy Esthela

    2012-01-01

    After peripheral nerve injury, a process of axonal degradation, debris clearance, and subsequent regeneration is initiated by complex local signaling, called Wallerian degeneration (WD). This process is in part mediated by neuroglia as well as infiltrating inflammatory cells and regulated by inflammatory mediators such as cytokines, chemokines, and the activation of transcription factors also related to the inflammatory response. Part of this neuroimmune signaling is mediated by the innate immune system, including arachidonic acid (AA) derivatives such as prostaglandins and leukotrienes. The enzymes responsible for their production, cyclooxygenases and lipooxygenases, also participate in nerve degeneration and regeneration. The interactions between signals for nerve regeneration and neuroinflammation go all the way down to the molecular level. In this paper, we discuss the role that AA derivatives might play during WD and nerve regeneration, and the therapeutic possibilities that arise. PMID:22997489

  2. Arachidonic and docosahexaenoic acids are biosynthesized from their 18-carbon precursors in human infants.

    PubMed Central

    Salem, N; Wegher, B; Mena, P; Uauy, R

    1996-01-01

    It is becoming clear that an adequate level of long-chain highly unsaturated fatty acids in the nervous system is required for optimal function and development; however, the ability of infants to biosynthesize long-chain fatty acids is unknown. This study explores the capacity of human infants to convert 18-carbon essential fatty acids to their elongated and desaturated forms, in vivo. A newly developed gas chromatography/negative chemical ionization/mass spectrometry method employing 2H-labeled essential fatty acids allowed assessment of this in vivo conversion with very high sensitivity and selectivity. Our results demonstrate that human infants have the capacity to convert dietary essential fatty acids administered enterally as 2H-labeled ethyl esters to their longer-chain derivatives, transport them to plasma, and incorporate them into membrane lipids. The in vivo conversion of linoleic acid (18:2n6) to arachidonic acid (20:4n6) is demonstrated in human beings. All elongases/desaturases necessary for the conversion of linolenic acid (18:3n3) to docosahexaenoic acid (22:6n3) are also active in the first week after birth. Although the absolute amounts of n-3 fatty acid metabolites accumulated in plasma are greater than those of the n-6 family, estimates of the endogenous pools of 18:2n6 and 18:3n3 indicate that n-6 fatty acid conversion rates are greater than those of the n-3 family. While these data clearly demonstrate the capability of infants to biosynthesize 22:6n3, a lipid that is required for optimal neural development, the amounts produced in vivo from 18:3n3 may be inadequate to support the 22:6n3 level observed in breast-fed infants. PMID:8552667

  3. CO-EXPOSURE OF HUMAN AIRWAY EPITHELIAL CELLS TO OZONE AND PARTICULATE MATTER: EFFECTS ON ARACHIDONIC ACID METABOLISM

    EPA Science Inventory

    Co-exposure of human airway epithelial cells to ozone and particulate matter: effects on arachidonic acid metabolism.

    D. Stamm1, L. Dailey2, M.C. Madden2
    1 University of North Carolina-Chapel Hill, School of Medicine
    2 U.S. EPA, ORD, NHEERL, HSD, Chapel Hill, NC, USA...

  4. The Polyunsaturated Fatty Acids Arachidonic Acid and Docosahexaenoic Acid Induce Mouse Dendritic Cells Maturation but Reduce T-Cell Responses In Vitro.

    PubMed

    Carlsson, Johan A; Wold, Agnes E; Sandberg, Ann-Sofie; Östman, Sofia M

    2015-01-01

    Long-chain polyunsaturated fatty acids (PUFAs) might regulate T-cell activation and lineage commitment. Here, we measured the effects of omega-3 (n-3), n-6 and n-9 fatty acids on the interaction between dendritic cells (DCs) and naïve T cells. Spleen DCs from BALB/c mice were cultured in vitro with ovalbumin (OVA) with 50 μM fatty acids; α-linolenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linoleic acid or oleic acid and thereafter OVA-specific DO11.10 T cells were added to the cultures. Fatty acids were taken up by the DCs, as shown by gas chromatography analysis. After culture with arachidonic acid or DHA CD11c+ CD11b+ and CD11c+ CD11bneg DCs expressed more CD40, CD80, CD83, CD86 and PDL-1, while IAd remained unchanged. However, fewer T cells co-cultured with these DCs proliferated (CellTrace Violet low) and expressed CD69 or CD25, while more were necrotic (7AAD+). We noted an increased proportion of T cells with a regulatory T cell (Treg) phenotype, i.e., when gating on CD4+ FoxP3+ CTLA-4+, CD4+ FoxP3+ Helios+ or CD4+ FoxP3+ PD-1+, in co-cultures with arachidonic acid- or DHA-primed DCs relative to control cultures. The proportion of putative Tregs was inversely correlated to T-cell proliferation, indicating a suppressive function of these cells. With arachidonic acid DCs produced higher levels of prostaglandin E2 while T cells produced lower amounts of IL-10 and IFNγ. In conclusion arachidonic acid and DHA induced up-regulation of activation markers on DCs. However arachidonic acid- and DHA-primed DCs reduced T-cell proliferation and increased the proportion of T cells expressing FoxP3, indicating that these fatty acids can promote induction of regulatory T cells.

  5. Epoxygenase metabolites of arachidonic acid inhibit vasopressin response in toad bladder

    SciTech Connect

    Schlondorff, D.; Petty, E.; Oates, J.A.; Jacoby, M.; Levine, S.D. Vanderbilt Univ., Nashville, TN )

    1987-09-01

    In addition to cyclooxygenase and lipoxygenase pathways, the kidney can also metabolize arachidonic acid by a NADPH-dependent cytochrome P-450 enzyme to epoxyeicosatrienoic acids (EETs); furthermore, 5,6-EET has been shown to alter electrolyte transport across isolated renal tubules. The authors examined the effects of three ({sup 14}C-labeled)-EETs (5,6-, 11,12-, and 14,15-EET) on osmotic water flow across toad urinary bladder. All three EETs reversibly inhibited vasopressin-stimulated osmotic water flow with 5,6- and 11,12-EET being the most potent. The effects appeared to be independent of prostaglandins EETs inhibited the water flow response to forskolin but not the response to adenosine 3{prime},5{prime}-cyclic monophosphate (cAMP) or 8-BrcAMP, consistent with an effect on cAMP generation. To determine whether these effects were due to the EETs or to products of their metabolism, they examined the effects of their vicinal diol hydrolysis products, the dihydroxyeicosatrienoic acids. Nonenzymatic conversion of labeled 5,6-EET to its vicinal diol occurred rapidly in the buffer, whereas 11,12-EET was hydrolyzed in a saturable manner only when incubated in the presence of bladder tissue. The dihydroxyeicosatrienoic acids formed inhibited water flow in a manner paralleling that of the EETs. The data support the hypothesis that EETs and their physiologically active dihydroxyeicosatrienoic acid metabolites inhibit vasopressin-stimulated water flow predominantly via inhibition of adenylate cyclase.

  6. The increased level of COX-dependent arachidonic acid metabolism in blood platelets from secondary progressive multiple sclerosis patients.

    PubMed

    Morel, Agnieszka; Miller, Elzbieta; Bijak, Michal; Saluk, Joanna

    2016-09-01

    Platelet activation is increasingly postulated as a possible component of the pathogenesis of multiple sclerosis (MS), especially due to the increased risk of cardiovascular events in MS. Arachidonic acid cascade metabolized by cyclooxygenase (COX) is a key pathway of platelet activation. The aim of our study was to investigate the COX-dependent arachidonic acid metabolic pathway in blood platelets from secondary progressive multiple sclerosis (SP MS) patients. The blood samples were obtained from 50 patients (man n = 22; female n = 28), suffering from SP MS, diagnosed according to the revised McDonald criteria. Platelet aggregation was measured in platelet-rich plasma after arachidonic acid stimulation. The level of COX activity and thromboxane B2 concentration were determined by ELISA method. Lipid peroxidation was assessed by measuring the level of malondialdehyde. The results were compared with a control group of healthy volunteers. We found that blood platelets obtained from SP MS patients were more sensitive to arachidonic acid and their response measured as platelet aggregation was stronger (about 14 %) relative to control. We also observed a significantly increased activity of COX (about 40 %) and synthesis of thromboxane B2 (about 113 %). The generation of malondialdehyde as a marker of lipid peroxidation was about 10 % higher in SP MS than in control. Cyclooxygenase-dependent arachidonic acid metabolism is significantly increased in blood platelets of patients with SP MS. Future clinical studies are required to recommend the use of low-dose aspirin, and possibly other COX inhibitors in the prevention of cardiovascular risk in MS.

  7. Arachidonic acid accumulates in the stromal macrophages during thymus involution in diabetes.

    PubMed

    Gruia, Alexandra T; Barbu-Tudoran, Lucian; Mic, Ani A; Ordodi, Valentin L; Paunescu, Virgil; Mic, Felix A

    2011-07-01

    Diabetes is a debilitating disease with chronic evolution that affects many tissues and organs over its course. Thymus is an organ that is affected early after the onset of diabetes, gradually involuting until it loses most of its thymocyte populations. We show evidence of accumulating free fatty acids with generation of eicosanoids in the diabetic thymus and we present a possible mechanism for the involution of the organ during the disease. Young rats were injected with streptozotocin and their thymuses examined for cell death by flow cytometry and TUNEL reaction. Accumulation of lipids in the diabetic thymus was investigated by histology and electron microscopy. The identity and quantitation of accumulating lipids was done with gas chromatography-mass spectrometry and liquid chromatography. The expression and dynamics of the enzymes were monitored via immunohistochemistry. Diabetes causes thymus involution by elevating the thymocyte apoptosis. Exposure of thymocytes to elevated concentration of glucose causes apoptosis. After the onset of diabetes, there is a gradual accumulation of free fatty acids in the stromal macrophages including arachidonic acid, the substrate for eicosanoids. The eicosanoids do not cause thymocyte apoptosis but administration of a cyclooxygenase inhibitor reduces the staining for ED1, a macrophage marker whose intensity correlates with phagocytic activity. Diabetes causes thymus involution that is accompanied by accumulation of free fatty acids in the thymic macrophages. Excess glucose is able to induce thymocyte apoptosis but eicosanoids are involved in the chemoattraction of macrophage to remove the dead thymocytes.

  8. IMAGING BRAIN SIGNAL TRANSDUCTION AND METABOLISM VIA ARACHIDONIC AND DOCOSAHEXAENOIC ACID IN ANIMALS AND HUMANS

    PubMed Central

    Basselin, Mireille; Ramadan, Epolia; Rapoport, Stanley I.

    2012-01-01

    The polyunsaturated fatty acids (PUFAs), arachidonic acid (AA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), important second messengers in brain, are released from membrane phospholipid following receptor-mediated activation of specific phospholipase A2 (PLA2) enzymes. We developed an in vivo method in rodents using quantitative autoradiography to image PUFA incorporation into brain from plasma, and showed that their incorporation rates equal their rates of metabolic consumption by brain. Thus, quantitative imaging of unesterified plasma AA or DHA incorporation into brain can be used as a biomarker of brain PUFA metabolism and neurotransmission. We have employed our method to image and quantify effects of mood stabilizers on brain AA/DHA incorporation during neurotransmission by muscarinic M1,3,5, serotonergic 5-HT2A/2C, dopaminergic D2-like (D2, D3, D4) or glutamatergic N-methyl-D-aspartic acid (NMDA) receptors, and effects of inhibition of acetylcholinesterase, of selective serotonin and dopamine reuptake transporter inhibitors, of neuroinflammation (HIV-1 and lipopolysaccharide) and excitotoxicity, and in genetically modified rodents. The method has been extended for the use with positron emission tomography (PET), and can be employed to determine how human brain AA/DHA signaling and consumption are influenced by diet, aging, disease and genetics. PMID:22178644

  9. Molecular Dynamics Simulations of Arachidonic Acid-Derived Pentadienyl Radical Intermediate Complexes with COX-1 and COX-2

    PubMed Central

    Furse, Kristina E.; Pratt, Derek A.; Schneider, Claus; Brash, Alan R.; Porter, Ned A.; Lybrand, Terry P.

    2008-01-01

    The two cyclooxygenase enzymes, COX-1 and COX-2, are responsible for the committed step in prostaglandin biosynthesis, and are the targets of the non-steroidal anti-inflammatory drugs aspirin, ibuprofen and the COX-2 selective inhibitors, Celebrex™, Vioxx™ and Bextra™. The enzymes are remarkable in that they catalyze two dioxygenations and two cyclizations of the native substrate, arachidonic acid, with near absolute regio- and stereoselectivity. Several theories have been advanced to explain the nature of enzymatic control over this series of reactions, including suggestions of steric shielding and oxygen channeling. As proposed here, selective radical trapping and spin localization in the substrate-derived pentadienyl radical intermediate can also be envisioned. Herein we describe the results of explicit, 10 ns molecular dynamics simulations of both COX-1 and COX-2 with the substrate-derived pentadienyl radical intermediate bound in the active site. The enzymes’ influence on the conformation of the pentadienyl radical was investigated, along with the accessible space above and below the radical plane, and the width of several channels to the active site that could function as access routes for molecular oxygen. Additional simulations demonstrated the extent of molecular oxygen mobility within the active site. The results suggest that spin localization is unlikely to play a role in enzymatic control of this reaction. Instead, a combination of oxygen channeling, steric shielding and selective radical trapping appears to be responsible. This work adds a dynamic perspective to the strong foundation of static structural data available for these enzymes. PMID:16519515

  10. Formula feeding potentiates docosahexaenoic and arachidonic acid biosynthesis in term and preterm baboon neonates.

    PubMed

    Sarkadi-Nagy, Eszter; Wijendran, Vasuki; Diau, Guan Yeu; Chao, Angela Chueh; Hsieh, Andrea T; Turpeinen, Anu; Lawrence, Peter; Nathanielsz, Peter W; Brenna, J Thomas

    2004-01-01

    Infant formulas supplemented with docosahexaenoic acid (DHA) and arachidonic acid (ARA) are now available in the United States; however, little is known about the factors that affect biosynthesis. Baboon neonates were assigned to one of four treatments: term, breast-fed; term, formula-fed; preterm (155 of 182 days gestation), formula-fed; and preterm, formula+DHA/ARA-fed. Standard formula had no DHA/ARA; supplemented formula had 0.61%wt DHA (0.3% of calories) and 1.21%wt ARA (0.6% of calories), and baboon breast milk contained 0.68 +/- 0.22%wt DHA and 0.62 +/- 0.12%wt ARA. At 14 days adjusted age, neonates received a combined oral dose of [U-13C]alpha-linolenic acid (LNA*) and [U-13C]linoleic acid (LA*), and tissues were analyzed 14 days after dose. Brain accretion of linolenic acid-derived DHA was approximately 3-fold greater for the formula groups than for the breast-fed group, and dietary DHA partially attenuated excess DHA synthesis among preterms. A similar, significant pattern was found in other organs. Brain linoleic acid-derived ARA accretion was significantly greater in the unsupplemented term group but not in the preterm groups compared with the breast-fed group. These data show that formula potentiates the biosynthesis/accretion of DHA/ARA in term and preterm neonates compared with breast-fed neonates and that the inclusion of DHA/ARA in preterm formula partially restores DHA/ARA biosynthesis to lower, breast-fed levels. Current formula DHA concentrations are inadequate to normalize long-chain polyunsaturated fatty acids synthesis to that of breast-fed levels.

  11. Arachidonic acid mediates the formation of abundant alpha-helical multimers of alpha-synuclein

    NASA Astrophysics Data System (ADS)

    Iljina, Marija; Tosatto, Laura; Choi, Minee L.; Sang, Jason C.; Ye, Yu; Hughes, Craig D.; Bryant, Clare E.; Gandhi, Sonia; Klenerman, David

    2016-09-01

    The protein alpha-synuclein (αS) self-assembles into toxic beta-sheet aggregates in Parkinson’s disease, while it is proposed that αS forms soluble alpha-helical multimers in healthy neurons. Here, we have made αS multimers in vitro using arachidonic acid (ARA), one of the most abundant fatty acids in the brain, and characterized them by a combination of bulk experiments and single-molecule Fӧrster resonance energy transfer (sm-FRET) measurements. The data suggest that ARA-induced oligomers are alpha-helical, resistant to fibril formation, more prone to disaggregation, enzymatic digestion and degradation by the 26S proteasome, and lead to lower neuronal damage and reduced activation of microglia compared to the oligomers formed in the absence of ARA. These multimers can be formed at physiologically-relevant concentrations, and pathological mutants of αS form less multimers than wild-type αS. Our work provides strong biophysical evidence for the formation of alpha-helical multimers of αS in the presence of a biologically relevant fatty acid, which may have a protective role with respect to the generation of beta-sheet toxic structures during αS fibrillation.

  12. An Optimized High Throughput Clean-Up Method Using Mixed-Mode SPE Plate for the Analysis of Free Arachidonic Acid in Plasma by LC-MS/MS.

    PubMed

    Wang, Wan; Qin, Suzi; Li, Linsen; Chen, Xiaohua; Wang, Qunjie; Wei, Junfu

    2015-01-01

    A high throughput sample preparation method was developed utilizing mixed-mode solid phase extraction (SPE) in 96-well plate format for the determination of free arachidonic acid in plasma by LC-MS/MS. Plasma was mixed with 3% aqueous ammonia and loaded into each well of 96-well plate. After washing with water and methanol sequentially, 3% of formic acid in acetonitrile was used to elute arachidonic acid. The collected fraction was injected onto a reversed phase column at 30°C with mobile phase of acetonitrile/water (70 : 30, v/v) and detected by LC-MS/MS coupled with electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The calibration curve ranged from 10 to 2500 ng/mL with sufficient linearity (r (2) = 0.9999). The recoveries were in the range of 99.38% to 103.21% with RSD less than 6%. The limit of detection is 3 ng/mL.

  13. Effect of selenium and vitamin E deficiencies on the fate of arachidonic acid in rat isolated lungs

    SciTech Connect

    Uotila, P.; Puustinen, T.

    1985-06-01

    The fate of exogenous /sup 14/C-arachidonic acid (/sup 14/C-AA) was investigated in the isolated lungs of rats fed selenium and vitamin E deficient diet or diets supplemented with selenium and/or vitamin E. When 80 nmol of /sup 14/C-AA was infused into the pulmonary circulation most of the infused /sup 14/C-AA was found in different phospholipid and neutral lipid fractions of the perfused lungs. Only less than ten percent of the infused radioactivity was recovered in the perfusion effluent. The amount of arachidonate metabolites in the perfusion effluent was negligible, and most of the radioactivity in the perfusion effluent consisted of unmetabolized arachidonate. Selenium deficiency had no significant effect on the distribution of /sup 14/C-AA in different lung lipid fractions. However, in the lungs of vitamin E deficient rats the amount of radioactivity was slightly increased in the neutral lipid fraction, which was due to the increased amount of /sup 14/C-AA in the diacylglycerols. The amount of radioactivity was increased especially in the 1,3-diacylglycerols. The amount of radioactivity was increased especially in the 1,3-diacylglycerols. The amount of /sup 14/C-AA in the triacylglycerols and in different phospholipids was not significantly changed. The present study might indicate that selenium deficiency has no significant effect on the fate of exogenous arachidonic acid in isolated rat lungs, and that vitamin E deficiency would slightly increase the amount of arachidonic acid in the diacylglycerols.

  14. Arachidonic acid impairs hypothalamic leptin signaling and hepatic energy homeostasis in mice.

    PubMed

    Cheng, Licai; Yu, Yinghua; Zhang, Qingsheng; Szabo, Alexander; Wang, Hongqin; Huang, Xu-Feng

    2015-09-05

    Epidemiological evidence suggests that the consumption of a diet high in n-6 polyunsaturated fatty acids (PUFA) is associated with the development of leptin resistance and obesity. We aim to examine the central effect of n-6 PUFA, arachidonic acid (ARA) on leptin sensitivity and leptin-regulated hepatic glucose and lipid metabolism. We found that intracerebroventricular injection of ARA (25 nmol/day) for 2.5 days reversed the effect of central leptin on hypothalamic JAK2, pSTAT3, pAkt, and pFOXO1 protein levels, which was concomitant with a pro-inflammatory response in the hypothalamus. ARA also attenuated the effect of central leptin on hepatic glucose and lipid metabolism by reversing the mRNA expression of the genes involved in gluconeogenesis (G6Pase, PEPCK), glucose transportation (GLUT2), lipogenesis (FAS, SCD1), and cholesterol synthesis (HMG-CoA reductase). These results indicate that an increased exposure to central n-6 PUFA induces central cellular leptin resistance with concomitant defective JAK2-STAT3 and PI3K-Akt signaling.

  15. Design, synthesis, and biological evaluation of conformationally constrained aci-reductone mimics of arachidonic acid.

    PubMed

    Hopper, A T; Witiak, D T; Ziemniak, J

    1998-02-12

    An efficient and convergent synthesis has been developed for the production of 3,4-dihydroxy-5-[4-(2-((2Z)-hexenyl)phenyl)-3-(1Z)-but enyl]-2 (5H)-furanone (12d). This hydrophobic antioxidant is a stable conformationally constrained mimic of arachidonic acid (AA) (1) and its respective aci-reductone analogue (2). Pd(0)-catalyzed cross-coupling of 5-(3-butynyl)-3,4-dihydroxy-2(5H)-furanone (7) with 2-((2Z)-hexenyl)iodobenzene (8d) followed by Lindlar catalyzed hydrogenation produces 12d. Butynyl intermediate 7 is prepared from 2-(benzyloxy)-5-deoxyascorbic acid (15) by iodination (I2, PPh3, Imd), iodo substitution with lithium acetylide ethylenediamine complex (LiAEDA, HMPA, -5 degrees C), and benzyl group cleavage (Ac2O, Pyr, BCl3). The utility of this synthetic method was demonstrated by the synthesis of analogues 10e-k. Biological testing revealed that certain of these antioxidants inhibit both cyclooxygenase (COX) and 5-lipoxygenase (5-LO) with comparable efficacy as reported for aspirin and zileuton, respectively. The antioxidant activity of these aci-reductones, measured as a function of their inhibitory effect on CCl4-induced lipid peroxidation of hepatic microsomes, exceeds that produced by alpha-tocopherol. Synthetic routes and initial structure-activity relationships (SAR) for these novel mixed functioning antioxidants are presented.

  16. Development of a defined medium for arachidonic acid production by Mortierella alpina using a visualization method.

    PubMed

    Liu, Xin; Ji, Xiaojun; Zhang, Hongman; Fu, Ninghua; Yan, Liexiang; Deng, Zhongtao; Huang, He

    2012-11-01

    Defined medium for arachidonic acid (ARA) production by Mortierella alpina was optimized for its metabolomics study. For this purpose, a visualization method (VM) was applied for the first time. Experiments were designed according to the uniform design with four factors (concentrations of glucose, NaNO(3), KH(2)PO(4) and MgSO(4)·7H(2)O) for each at nine levels. Dry cell weight (DCW), ARA yield in DCW [percent (w/w)] and ARA content in total fatty acids [percent (w/w)] were considered as the three objectives. Optimization of single-objective function and multi-objective function of two objectives and three objectives was attempted. Optimal DCW, ARA yield and ARA content were predicted to occur in a medium that contained (grams per litre): glucose 35, NaNO(3) 1, KH(2)PO(4) 7.5 and MgSO(4)·7H(2)O 2.6. Upon verification, the average tested DCW (12.95 g/l), ARA yield (18.89 %) and ARA content (42.36 %) were fairly close to the predicted values (12.88 g/l, 9.68 % and 35.57 %, respectively). Moreover, DCW, ARA yield and ARA content from the optimum medium increased by 35.68, 47.23 and 30.90 % compared with control, respectively, indicating that VM had succeeded in exploiting the biomass growth and ARA production by M. alpina.

  17. Relative incorporation of arachidonic and eicosapentaenoic acids into human platelet phospholipids

    SciTech Connect

    Weaver, B.J.; Holub, B.J.

    1985-11-01

    The incorporation of arachidonic acid (AA) as compared to eicosapentaenoic acid (EPA) into human platelet phospholipids was tested by incubating washed platelets with a known mixture of (3H)AA and (14C)EPA. Following incubation, the platelet lipids were extracted, the individual phospholipids--phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI) and phosphatidylethanolamine (PE)- were separated by thin layer chromatography, and their corresponding (3H)/(14C) ratios were determined. Based on a (3H)/(14C) ratio of unity for the substrate mixture, the PC, PS, PI and PE exhibited ratios of 0.55, 0.93, 1.12 and 0.74, respectively, which were significantly different from 1.00 in all instances except in the case of PS. These results indicate that PC and PE selectively incorporated EPA, while PI showed preference toward AA. These selectivities may account partly for the differing AA/EPA mass ratios that have been observed among the individual phospholipids of human subjects consuming fish oils.

  18. Cytochrome P450 metabolites of arachidonic acid are elevated in stroke patients compared with healthy controls.

    PubMed

    Ward, Natalie C; Croft, Kevin D; Blacker, David; Hankey, Graeme J; Barden, Anne; Mori, Trevor A; Puddey, Ian B; Beer, Christopher D

    2011-12-01

    CYP450AAM [arachidonic acid metabolites of the CYP450 (cytochrome P450) enzyme system] have a range of biological functions. CYP450AAM are involved in the pathogenesis of hypertension, renal function and vascular function, yet their role in stroke has not been clarified. We aimed at determining the levels of circulating CYP450 metabolites in patients with acute ischaemic stroke (<96 h) compared with healthy age- and gender-matched controls. This was a retrospective case-controlled study of 44 acute ischaemic stroke patients and 44 matched controls. A subset of acute ischaemic stroke patients was available for follow-up. Acute ischaemic stroke patients had elevated plasma CYP450AAM, including 20-HETE (20-hydroxyeicosatetraenoic acid) (1921±170 compared with 1108±170 pmol/l, P<0.001), EETs (epoxyeicosatrienoic acids) (77.88±3.34 compared with 35.35±3.34 nmol/l, P<0.0001) and DiHETEs (dihydroxyeicosatetraenoic acids) (92.87±4.61 compared with 68.17±4.61 nmol/l, P<0.0001), as well as increased plasma F2-isoprostane levels (3754±538 compared with 1947±538 pmol/l, P<0.02), the latter a marker of oxidative stress, compared with controls. In a subset analysis of the stroke patients, plasma 20-HETE, EETs and F2-isoprostanes were attenuated 30 days after the stroke. Baseline 20-HETE levels were also associated with lesion size and functional indices within the stroke patients. The present study highlights the elevation in CYP450AAM and oxidative stress in acute ischaemic stroke patients. Further investigation of the effect this has on long-term clinical outcome or whether this can be modified by treatment is warranted.

  19. Systemic elevations of free radical oxidation products of arachidonic acid are associated with angiographic evidence of coronary artery disease.

    PubMed

    Shishehbor, Mehdi H; Zhang, Renliang; Medina, Hector; Brennan, Marie-Luise; Brennan, Danielle M; Ellis, Stephen G; Topol, Eric J; Hazen, Stanley L

    2006-12-01

    Oxidant stress is widely believed to participate in cardiovascular disease pathogenesis. However, progress in defining appropriate systemic antioxidant targeted therapies has been hindered by uncertainty in defining clinically relevant systemic oxidant stress measures. In a case control study, 50 subjects with CAD (>50% stenosis in one or more major coronary vessels) and 54 without CAD (<30% stenosis in all major coronary vessels) were tested. Plasma was isolated and stored under conditions designed to prevent artificial lipid peroxidation. Systemic levels of multiple (n=9) specific fatty acid oxidation products including individual hydroxyoctadecadienoic acids (HODEs), hydroxyeicosatetraenoic acids (HETEs), and F(2)-isoprostanes were simultaneously measured by high-performance liquid chromatography (HPLC) with on-line tandem mass spectrometry, along with traditional risk factors and C-reactive protein (CRP) levels. Of the markers monitored, only 9-HETE and F(2)-isoprostanes, both products of free radical-mediated arachidonic acid oxidation, were significantly elevated in patients with angiographically defined CAD (9-HETE, 8.7 +/- 4 vs 6.8 +/- 4 micromol/mol arachidonate, P = 0.011; and F(2)-isoprostanes, 9.4 +/- 5 vs 6.2 +/- 3 micromol/mol arachidonate, P < 0.001). In multivariable analyses with simultaneous adjustment for Framingham risk score and C-reactive protein, 9-HETE (4th quartile OR = 4.8, 95% CI=1.3 to 17.1; P = 0.016) and F(2)-isoprostanes (4th quartile OR=9.7, 95% CI=2.56 to 36.9; P < 0.001) remained strong and independent predictors of CAD risk. Systemic levels of 9-HETE and F(2)-isoprostanes are independently associated with angiographic evidence of CAD and appear superior to other specific oxidation products of arachidonic and linoleic acids as predictors of the presence of angiographically evident coronary artery disease.

  20. Qishen granules inhibit myocardial inflammation injury through regulating arachidonic acid metabolism

    PubMed Central

    Li, Chun; Wang, Jing; Wang, Qiyan; Zhang, Yi; Zhang, Na; Lu, Linghui; Wu, Yan; Zhang, Qian; Wang, Wei; Wang, Yong; Tu, Pengfei

    2016-01-01

    Qishen granules (QSG), a traditional Chinese medicine, have been prescribed widely in the treatment of coronary heart diseases. Previous studies demonstrated that QSG had anti-inflammatory and cardio-protective effects in mice with acute myocardial infarction (AMI). However, the mechanisms by which QSG attenuate inflammation and prevent post-AMI heart failure (HF) are still unclear. In this study, we explored the anti-inflammatory mechanisms of QSG by in vitro and in vivo experiments. A novel inflammatory injury model of H9C2 cells was induced by lipopolysaccharide (LPS)-stimulated macrophage-conditioned media (CM). An animal model of AMI was conducted by ligation of left anterior descending (LAD) coronary artery in mice. We found that QSG inhibited release of cytokines from LPS-stimulated RAW 264.7 macrophages and protected H9C2 cardiac cells against CM-induced injury. In vivo results showed that QSG administration could improve cardiac functions and alter pathological changes in model of AMI. QSG regulated multiple key molecules, including phospholipases A2 (PLA2), cyclooxygenases (COXs) and lipoxygenases (LOXs), in arachidonic acid metabolism pathway. Interestingly, QSG also targeted TNF-α-NF-κB and IL-6-JAK2-STAT3 signaling pathways. Taken together, QSG achieve synergistic effects in mitigating post-AMI HF by regulating multiple targets in inflammatory pathways. This study provides insights into anti-inflammatory therapeutics in managing HF after AMI. PMID:27833128

  1. Effect of heavy metal ions on neutrophil arachidonic acid metabolism and chemotaxis

    SciTech Connect

    Smith, D.M.; Turner, S.R.; Johnson, J.A.; Turner, R.A.

    1986-05-01

    Heavy metal ions can inhibit arachidonic acid (AA) metabolism, protect against ionophore cytotoxicity (ibid) and inhibit neutrophil chemotaxis. In this study they used Au/sup +3/, Zn/sup +2/, Cr/sup +3/, Mn/sup +2/, and Cu/sup +2/ as probes of the interrelationships among AA metabolism, ionophore-mediated cytotoxicity, and chemotaxis. Phospholipid deacylation was measured in ionophore-treated cells prelabeled with /sup 3/H-AA. Eicosanoid release from ionophore-treated cells was monitored both qualitatively by thin-layer chromatography of /sup 3/H-AA metabolities and quantitatively by radioimmunoassay. Cytoprotection was quantitated as ability to exclude trypan blue. Chemotaxis toward f-Met-Leu-Phe was measured by leading front analysis. The results imply that metal ions attenuate ionophore cytotoxicity by blocking phospholipid deacylation and eicosanoid production. In contrast to previous reports, the data obtained using Au/sup +3/ and Cu/sup +2/ demonstrates no correlation between AA metabolism and chemotaxis, suggesting that these 2 processes are not linked.

  2. LPIAT1 regulates arachidonic acid content in phosphatidylinositol and is required for cortical lamination in mice

    PubMed Central

    Lee, Hyeon-Cheol; Inoue, Takao; Sasaki, Junko; Kubo, Takuya; Matsuda, Shinji; Nakasaki, Yasuko; Hattori, Mitsuharu; Tanaka, Fumiharu; Udagawa, Osamu; Kono, Nozomu; Itoh, Toshiki; Ogiso, Hideo; Taguchi, Ryo; Arita, Makoto; Sasaki, Takehiko; Arai, Hiroyuki

    2012-01-01

    Dietary arachidonic acid (AA) has roles in growth, neuronal development, and cognitive function in infants. AA is remarkably enriched in phosphatidylinositol (PI), an important constituent of biological membranes in mammals; however, the physiological significance of AA-containing PI remains unknown. In an RNA interference–based genetic screen using Caenorhabditis elegans, we recently cloned mboa-7 as an acyltransferase that selectively incorporates AA into PI. Here we show that lysophosphatidylinositol acyltransferase 1 (LPIAT1, also known as MBOAT7), the closest mammalian homologue, plays a crucial role in brain development in mice. Lpiat1−/− mice show almost no LPIAT activity with arachidonoyl-CoA as an acyl donor and show reduced AA contents in PI and PI phosphates. Lpiat1−/− mice die within a month and show atrophy of the cerebral cortex and hippocampus. Immunohistochemical analysis reveals disordered cortical lamination and delayed neuronal migration in the cortex of E18.5 Lpiat1−/− mice. LPIAT1 deficiency also causes disordered neuronal processes in the cortex and reduced neurite outgrowth in vitro. Taken together, these results demonstrate that AA-containing PI/PI phosphates play an important role in normal cortical lamination during brain development in mice. PMID:23097495

  3. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    PubMed

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L.

  4. Metabolomics analysis of fungal biofilm development and of arachidonic acid-based quorum sensing mechanism.

    PubMed

    Ząbek, Adam; Junka, Adam; Szymczyk, Patrycja; Wojtowicz, Wojciech; Klimek-Ochab, Magdalena; Młynarz, Piotr

    2017-04-03

    The infections caused by filamentous fungi are becoming worldwide problem of healthcare systems due to increasing drug-resistance of this microorganism and increasing number of immunocompromised nosocomial patients. These infections are related with Aspergillus ability to form sessile communities referred to as the biofilms. The small compounds known as quorum sensing (QS) molecules allow this microorganism to coordinate all processes taking place during biofilm formation and maturation. In the study presented, the HRMAS (1) H NMR metabolomic approach was applied to define composition of extra and intracellular metabolites produced by biofilmic and planktonic (aka free-swimming) cultures of this microorganism and to evaluate impact of quorum sensing molecule, arachidonic acid (AA) on biofilm formation. The Scanning Electron Microscopy was used to confirm Aspergillus ability to form biofilm in vitro, while multivariate and univariate data analysis was applied to analyze data obtained. The Aspergillus strain was able to form strong biofilm structures in vitro. The statistical analysis revealed significant changes of metabolite production depending on Aspergillus culture type (biofilm vs. plankton), time and presence of QS molecules. The data obtained, if developed, might be used in future NMR diagnostics as markers of Aspergillus biofilm-related infections and lead to shorten time between pathogen identification and introduction of treatment.

  5. On the cellular metabolism of the click chemistry probe 19-alkyne arachidonic acid.

    PubMed

    Robichaud, Philippe Pierre; Poirier, Samuel J; Boudreau, Luc H; Doiron, Jérémie A; Barnett, David A; Boilard, Eric; Surette, Marc E

    2016-10-01

    Alkyne and azide analogs of natural compounds that can be coupled to sensitive tags by click chemistry are powerful tools to study biological processes. Arachidonic acid (AA) is a FA precursor to biologically active compounds. 19-Alkyne-AA (AA-alk) is a sensitive clickable AA analog; however, its use as a surrogate to study AA metabolism requires further evaluation. In this study, AA-alk metabolism was compared with that of AA in human cells. Jurkat cell uptake of AA was 2-fold greater than that of AA-alk, but significantly more AA-Alk was elongated to 22:4. AA and AA-alk incorporation into and remodeling between phospholipid (PL) classes was identical indicating equivalent CoA-independent AA-PL remodeling. Platelets stimulated in the pre-sence of AA-alk synthesized significantly less 12-lipoxygenase (12-LOX) and cyclooxygenase products than in the presence of AA. Ionophore-stimulated neutrophils produced significantly more 5-LOX products in the presence of AA-alk than AA. Neutrophils stimulated with only exogenous AA-alk produced significantly less 5-LOX products compared with AA, and leukotriene B4 (LTB4)-alk was 12-fold less potent at stimulating neutrophil migration than LTB4, collectively indicative of weaker leukotriene B4 receptor 1 agonist activity of LTB4-alk. Overall, these results suggest that the use of AA-alk as a surrogate for the study of AA metabolism should be carried out with caution.

  6. Arachidonic acid randomizes endothelial cell motion and regulates adhesion and migration.

    PubMed

    Rossen, Ninna Struck; Hansen, Anker Jon; Selhuber-Unkel, Christine; Oddershede, Lene Broeng

    2011-01-01

    Cell adhesion and migration are essential for the evolution, organization, and repair of living organisms. An example of a combination of these processes is the formation of new blood vessels (angiogenesis), which is mediated by a directed migration and adhesion of endothelial cells (ECs). Angiogenesis is an essential part of wound healing and a prerequisite of cancerous tumor growth. We investigated the effect of the amphiphilic compound arachidonic acid (AA) on EC adhesion and migration by combining live cell imaging with biophysical analysis methods. AA significantly influenced both EC adhesion and migration, in either a stimulating or inhibiting fashion depending on AA concentration. The temporal evolution of cell adhesion area was well described by a two-phase model. In the first phase, the spreading dynamics were independent of AA concentration. In the latter phase, the spreading dynamics increased at low AA concentrations and decreased at high AA concentrations. AA also affected EC migration; though the instantaneous speed of individual cells remained independent of AA concentration, the individual cells lost their sense of direction upon addition of AA, thus giving rise to an overall decrease in the collective motion of a confluent EC monolayer into vacant space. Addition of AA also caused ECs to become more elongated, this possibly being related to incorporation of AA in the EC membrane thus mediating a change in the viscosity of the membrane. Hence, AA is a promising non-receptor specific regulator of wound healing and angiogenesis.

  7. Lysophosphatidylcholine Acyltransferase 3 Is the Key Enzyme for Incorporating Arachidonic Acid into Glycerophospholipids during Adipocyte Differentiation

    PubMed Central

    Eto, Miki; Shindou, Hideo; Koeberle, Andreas; Harayama, Takeshi; Yanagida, Keisuke; Shimizu, Takao

    2012-01-01

    Cellular membranes contain glycerophospholipids, which have important structural and functional roles in cells. Glycerophospholipids are first formed in the de novo pathway (Kennedy pathway) and are matured in the remodeling pathway (Lands’ cycle). Recently, lysophospholipid acyltransferases functioning in Lands’ cycle were identified and characterized. Several enzymes involved in glycerophospholipid biosynthesis have been reported to have important roles in adipocytes. However, the role of Lands’ cycle in adipogenesis has not yet been reported. Using C3H10T1/2, a cell line capable of differentiating to adipocyte-like cells in vitro, changes of lysophospholipid acyltransferase activities were investigated. Lysophosphatidylcholine acyltransferase (LPCAT), lysophosphatidylethanolamine acyltransferase (LPEAT) and lysophosphatidylserine acyltransferase (LPSAT) activities were enhanced, especially with 18:2-CoA and 20:4-CoA as donors. Correspondingly, mRNA expression of LPCAT3, which possesses LPCAT, LPEAT and LPSAT activities with high specificity for 18:2- and 20:4-CoA, was upregulated during adipogenesis. Analysis of acyl-chain compositions of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) showed a change in their profiles between preadipocytes and adipocytes, including an increase in the percentage of arachidonic acid-containing phospholipids. These changes are consistent with the activities of LPCAT3. Therefore, it is possible that enhanced phospholipid remodeling by LPCAT3 may be associated with adipocyte differentiation. PMID:23208369

  8. Accumulation of arachidonic acid-containing phosphatidylinositol at the outer edge of colorectal cancer

    PubMed Central

    Hiraide, Takanori; Ikegami, Koji; Sakaguchi, Takanori; Morita, Yoshifumi; Hayasaka, Takahiro; Masaki, Noritaka; Waki, Michihiko; Sugiyama, Eiji; Shinriki, Satoru; Takeda, Makoto; Shibasaki, Yasushi; Miyazaki, Shinichiro; Kikuchi, Hirotoshi; Okuyama, Hiroaki; Inoue, Masahiro; Setou, Mitsutoshi; Konno, Hiroyuki

    2016-01-01

    Accumulating evidence indicates that cancer cells show specific alterations in phospholipid metabolism that contribute to tumour progression in several types of cancer, including colorectal cancer. Questions still remain as to what lipids characterize the outer edge of cancer tissues and whether those cancer outer edge-specific lipid compositions emerge autonomously in cancer cells. Cancer tissue-originated spheroids (CTOSs) that are composed of pure primary cancer cells have been developed. In this study, we aimed to seek out the cancer cell-autonomous acquisition of cancer outer edge-characterizing lipids in colorectal cancer by analysing phospholipids in CTOSs derived from colorectal cancer patients with matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS). A signal at m/z 885.5 in negative ion mode was detected specifically at the surface regions. The signal was identified as an arachidonic acid (AA)-containing phosphatidylinositol (PI), PI(18:0/20:4), by tandem mass spectrometry analysis. Quantitative analysis revealed that the amount of PI(18:0/20:4) in the surface region of CTOSs was two-fold higher than that in the medial region. Finally, PI(18:0/20:4) was enriched at the cancer cells/stromal interface in colorectal cancer patients. These data imply a possible importance of AA-containing PI for colorectal cancer progression, and suggest cells expressing AA-containing PI as potential targets for anti-cancer therapy. PMID:27435310

  9. Is increased arachidonic acid release a cause or a consequence of replicative senescence?

    PubMed

    Lorenzini, A; Hrelia, S; Bordoni, A; Biagi, P; Frisoni, L; Marinucci, T; Cristofalo, V J

    2001-01-01

    Arachidonic acid (AA) has been related to both stimulation and inhibition of cellular proliferation. During replicative senescence of human fibroblasts, increased levels of AA have been thought to play a causal role in the limited proliferative capacity of the cells. To clarify the role of AA in the proliferation of normal fibroblasts and in cellular senescence, we examined uptake from and release of AA into the culture media and its effects on DNA synthesis. Our results indicate that some aspects of AA metabolism in normal human fibroblasts aged in culture are significantly different in comparison to early passage cells. Particularly, AA release following different mitogenic stimulation is higher in senescent than in young cells. Notwithstanding this significant difference, AA, at the concentration used, has no inhibitory effect on fibroblast DNA synthesis. Moreover AA and prostaglandins are responsible for the proliferative block in neither senescent cells nor mediate ceramide inhibition of DNA synthesis. So our results suggest that the increasing AA release is not causal, but rather the result of in vitro aging.

  10. Altered macrophage arachidonic acid metabolism induced by endotoxin tolerance: characterization and mechanisms

    SciTech Connect

    Rogers, T.S.

    1986-01-01

    Altered macrophage arachidonic acid (AA) metabolism may play a role in endotoxic shock and the phenomenon of endotoxin tolerance induced by repeated injections of endotoxin. Studies were initiated to characterize both lipoxygenase and cyclooxygenase metabolite formation by endotoxin tolerant and non-tolerant macrophages in response to 4 different stimuli, i.e., endotoxin, glucan, zymosan, and the calcium ionophore A23187. In contrast to previous reports of decreased prostaglandin synthesis by tolerant macrophages, A23187-stimulated immunoreactive (i) leukotriene (LT) C/sub 4/D/sub 4/ and prostaglandin (PG) E/sub 2/ production by tolerant cells was greater than that by non-tolerant controls (p <0.001). However, A23187-stimulated i6-keto PGF/sub 1a/ levels were lower in tolerant macrophages compared to controls (P < 0.05). iL TC/sub 4/D/sub 4/ production was not significantly stimulated by endotoxin or glucan, but was stimulated by zymosan in non-tolerant cells. Synthesis of iLTB/sub 4/ by control macrophages was stimulated by endotoxin (p <0.01). The effect of tolerance on factors that affect AA release was investigated by measuring /sup 14/C-AA incorporation and release and phospholipase A/sub 2/ activity

  11. Role of arachidonic acid lipoxygenase metabolites in acetylcholine-induced relaxations of mouse arteries

    PubMed Central

    Goldman, Daniel H.; Aggarwal, Nitin T.; Chawengsub, Yuttana; Falck, J. R.; Campbell, William B.

    2011-01-01

    Arachidonic acid (AA) metabolites function as EDHFs in arteries of many species. They mediate cyclooxygenase (COX)- and nitric oxide (NO)-independent relaxations to acetylcholine (ACh). However, the role of AA metabolites as relaxing factors in mouse arteries remains incompletely defined. ACh caused concentration-dependent relaxations of the mouse thoracic and abdominal aorta and carotid, femoral, and mesentery arteries (maximal relaxation: 57 ± 4%, 72 ± 4%, 82 ± 3%, 80 ± 3%, and 85 ± 3%, respectively). The NO synthase inhibitor nitro-l-arginine (l-NA; 30 μM) blocked relaxations in the thoracic aorta, and l-NA plus the COX inhibitor indomethacin (10 μM) inhibited relaxations in the abdominal aorta and carotid, femoral, and mesenteric arteries (maximal relaxation: 31 ± 10%, 33 ± 5%, 41 ± 8%, and 73 ± 3%, respectively). In mesenteric arteries, NO- and COX-independent relaxations to ACh were inhibited by the lipoxygenase (LO) inhibitors nordihydroguaiaretic acid (NDGA; 10 μM) and BW-755C (200 μM), the K+ channel inhibitor apamin (1 μM), and 60 mM KCl and eliminated by endothelium removal. They were not altered by the cytochrome P-450 inhibitor N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (20 μM) or the epoxyeicosatrienoic acid antagonist 14,15-epoxyeicosa-5(Z)-enoic acid (10 μM). AA relaxations were attenuated by NDGA or apamin and eliminated by 60 mM KCl. Reverse-phase HPLC analysis revealed arterial [14C]AA metabolites that comigrated with prostaglandins, trihydroxyeicosatrienoic acids (THETAs), hydroxyepoxyeicosatrienoic acids (HEETAs), and hydroxyeicosatetraenoic acids (HETEs). Epoxyeicosatrienoic acids were not observed. Mass spectrometry confirmed the identity of 6-keto-PGF1α, PGE2, 12-HETE, 15-HETE, HEETAs, 11,12,15-THETA, and 11,14,15-THETA. AA metabolism was blocked by NDGA and endothelium removal. 11(R),12(S),15(S)-THETA relaxations (maximal relaxation: 73 ± 3%) were endothelium independent and blocked by 60 mM KCl. Western

  12. Repurposing Resveratrol and Fluconazole To Modulate Human Cytochrome P450-Mediated Arachidonic Acid Metabolism.

    PubMed

    El-Sherbeni, Ahmed A; El-Kadi, Ayman O S

    2016-04-04

    Cytochrome P450 (P450) enzymes metabolize arachidonic acid (AA) to several biologically active epoxyeicosatrienoic acids (EETs) and hydroxyeicosatetraenoic acids (HETEs). Repurposing clinically-approved drugs could provide safe and readily available means to control EETs and HETEs levels in humans. Our aim was to determine how to significantly and selectively modulate P450-AA metabolism in humans by clinically-approved drugs. Liquid chromatography-mass spectrometry was used to determine the formation of 15 AA metabolites by human recombinant P450 enzymes, as well as human liver and kidney microsomes. CYP2C19 showed the highest EET-forming activity, while CYP1B1 and CYP2C8 showed the highest midchain HETE-forming activities. CYP1A1 and CYP4 showed the highest subterminal- and 20-HETE-forming activity, respectively. Resveratrol and fluconazole produced the most selective and significant modulation of hepatic P450-AA metabolism, comparable to investigational agents. Monte Carlo simulations showed that 90% of human population would experience a decrease by 6-22%, 16-39%, and 16-35% in 16-, 18-, and 20-HETE formation, respectively, after 2.5 g daily of resveratrol, and by 22-31% and 14-23% in 8,9- and 14,15-EET formation after 50 mg of fluconazole. In conclusion, clinically-approved drugs can provide selective and effective means to modulate P450-AA metabolism, comparable to investigational drugs. Resveratrol and fluconazole are good candidates to be repurposed as new P450-based treatments.

  13. Effect of arachidonic and eicosapentaenoic acid metabolism on RAW 264.7 macrophage proliferation.

    PubMed

    Nieves, Diana; Moreno, Juan José

    2006-08-01

    Prostaglandins (PGs) and leukotrienes (LTs) derived from arachidonic acid (AA) are potent mediators of inflammation and cell proliferation. Dietary intake of eicosapentaenoic acid (EPA) appears beneficial to both inflammatory processes and cell proliferation. However, there is no clear mechanism explaining these effects. In this study, we investigated the effect of EPA on the AA incorporation in phospholipid membranes, on AA release and metabolism, and consequently, on PG synthesis. Our results showed not only that [(3)H]AA and [(14)C]EPA were similar incorporated into RAW 264.7 macrophage membranes, but also that the redistribution pattern between phospholipids was alike. [(3)H]AA or [(14)C]EPA release was induced by fetal bovine serum (FBS) in a similar fashion with AA metabolizing 3-fold more than EPA. In this way, we observed that AA could be metabolized by cyclooxygenase (COX)-1, COX-2 and 5-lipoxygenase (5-LOX) whereas EPA was metabolized by COX-2 and 5-LOX pathways. Moreover, both fatty acids were able to induce COX-2 expression. When we incubated [(3)H]AA labeled cells with exogenous EPA, we observed that EPA did not modify FBS-induced [(3)H]AA release but that the presence of EPA decreased [(3)H]AA metabolism and therefore PGE(2) synthesis. Moreover, we studied the effect of AA and EPA metabolites on macrophage proliferation. Our results showed that PGE(3) stimulated cell growth with a potency similar to that of PGE(2), whereas LTB(5) was less effective than LTB(4). These data suggest that the effects of EPA on cell growth might be attributable, at least in part, to the marked decrease of eicosanoid release.

  14. Arachidonic acid incorporation and turnover is decreased in sympathetically denervated rat heart.

    PubMed

    Patrick, Casey B; McHowat, Jane; Rosenberger, Thad A; Rapoport, Stanley I; Murphy, Eric J

    2005-06-01

    Heart sympathetic denervation can accompany Parkinson's disease, but the effect of this denervation on cardiac lipid-mediated signaling is unknown. To address this issue, rats were sympathetically denervated with 6-hydroxydopamine (6-OHDA, 50 mg/kg ip) and infused with 170 muCi/kg of either [1-(14)C]palmitic acid ([1-(14)C]16:0) or [1-(14)C]arachidonic acid ([1-(14)C]20:4 n-6), and kinetic parameters were assessed using a steady-state radiotracer model. Heart norepinephrine and epinephrine levels were decreased 82 and 85%, respectively, in denervated rats, and this correlated with a 34% reduction in weight gain in treated rats. Fatty acid tracer uptake was not significantly different between groups for either tracer, although the dilution coefficient lambda was increased in [1-(14)C]20:4 n-6-infused rats, which indicates that less 20:4 n-6 was recycled in denervated rats. In [1-(14)C]16:0-infused rats, incorporation rate and turnover values of 16:0 in stable lipid compartments were unchanged, which is indicative of preservation of beta-oxidation. In [1-(14)C]20:4 n-6-infused rats, there were dramatic reductions in incorporation rate (60-84%) and turnover value (56-85%) in denervated rats that were dependent upon the lipid compartment. In addition, phospholipase A(2) activity was reduced 40% in treated rats, which is consistent with the reduction observed in 20:4 n-6 turnover. These results demonstrate marked reductions in 20:4 n-6 incorporation rate and turnover in sympathetic denervated rats and thereby suggest an effect on lipid-mediated signal transduction mediated by a reduction in phospholipase A(2) activity.

  15. Stimulus-specific induction of phospholipid and arachidonic acid metabolism in human neutrophils

    SciTech Connect

    Godfrey, R.W.; Manzi, R.M.; Clark, M.A.; Hoffstein, S.T.

    1987-04-01

    Phospholipid remodeling resulting in arachidonic acid (AA) release and metabolism in human neutrophils stimulated by calcium ionophore A23187 has been extensively studied, while data obtained using physiologically relevant stimuli is limited. Opsonized zymosan and immune complexes induced stimulus-specific alterations in lipid metabolism that were different from those induced by A23187. (/sup 3/H)AA release correlated with activation of phospholipase A2 (PLA2) but not with cellular activation as indicated by superoxide generation. The latter correlated more with calcium-dependent phospholipase C (PLC) activation and elevation of cellular diacylglycerol (DAG) levels. When cells that had been allowed to incorporate (/sup 3/H)AA were stimulated with A23187, large amounts of labeled AA was released, most of which was metabolized to 5-HETE and leukotriene B4. Stimulation with immune complexes also resulted in the release of (/sup 3/H)AA but this released radiolabeled AA was not metabolized. In contrast, stimulation with opsonized zymosan induced no detectable release of (/sup 3/H)AA. Analysis of (/sup 3/H)AA-labeled lipids in resting cells indicated that the greatest amount of label was incorporated into the phosphatidylinositol (PI) pool, followed closely by phosphatidylcholine and phosphatidylserine, while little (/sup 3/H)AA was detected in the phosphatidylethanolamine pool. During stimulation with A23187, a significant decrease in labeled PI occurred and labeled free fatty acid in the pellet increased. With immune complexes, only a small decrease was seen in labeled PI while the free fatty acid in the pellets was unchanged. In contrast, opsonized zymosan decreased labeled PI, and increased labeled DAG. Phospholipase activity in homogenates from human neutrophils was also assayed. A23187 and immune complexes, but not zymosan, significantly enhanced PLA2 activity in the cell homogenates. On the other hand, PLC activity was enhanced by zymosan and immune complexes

  16. Protective effects of arachidonic acid against palmitic acid-mediated lipotoxicity in HIT-T15 cells.

    PubMed

    Cho, Young Sik; Kim, Chi Hyun; Kim, Ki Young; Cheon, Hyae Gyeong

    2012-05-01

    Saturated fatty acids have been considered major contributing factors in type 2 diabetes, whereas unsaturated fatty acids have beneficial effects for preventing the development of diabetes. However, the effects of polyunsaturated fatty acids in pancreatic β cells have not been reported. Here, we examined the effects of arachidonic acid (AA) on palmitic acid (PA)-mediated lipotoxicity in clonal HIT-T15 pancreatic β cells. AA prevented the PA-induced lipotoxicity as indicated by cell viability, DNA fragmentation and mitochondrial membrane potential, whereas eicosatetraynoic acid (ETYA), a non-metabolizable AA, had little effect on PA-induced lipotoxicity. In parallel with its protective effects against PA-induced lipotoxicity, AA restored impaired insulin expression and secretion induced by PA. AA but not ETYA increased intracellular triglyceride (TG) in the presence of PA compared with PA alone, and xanthohumol, a diacylglycerol acyltransferase (DGAT) inhibitor, reversed AA-induced protection from PA. Taken together, our results suggest that AA protects against PA-induced lipotoxicity in clonal HIT-T15 pancreatic β cells, and the protective effects may be associated with TG accumulation, possibly through sequestration of lipotoxic PA into TG.

  17. /sup 3/H arachidonic acid incorporation and metabolism in purified human basophils

    SciTech Connect

    Warner, J.A.; Peters, S.P.; Lichtenstein, L.M.; MacGlashan, D.W. Jr.

    1986-03-01

    A central feature of the allergic response is the generation of arachidonic acid (AA) metabolites by basophils and mast cells. In addition, AA metabolism may play a role in regulating the anti-IgE mediated degranulation of human basophils. To study this biochemistry, purified human basophils (>80%) were labeled with /sup 3/H-AA (0.3 ..mu..M, 25 ..mu..Ci/ml, 2 hours at 37/sup 0/C) and subsequently challenged with anti-IgE. Basophils were found to incorporate 45 +/- 3% of the exogenous AA which distributed into phospholipids (PL) (77.1 +/- 3.5%) and neutral lipids (19.7 +/- 3.3%) with only 5.3 +/- 2.7% remaining as the free acid (n = 7). Phosphatidylcholine (23.9 +/- 1.7%), phosphatidylinositol (22.0 +/- 1.4%) and phosphatidylethanolamine (14.5 +/- 2.7%) accounted for the majority of the AA with the remaining PL containing <3%. Anti-IgE (0.1 ..mu..g/ml) challenge led to the release of histamine (23.8 +/- 4.7%) and /sup 3/H-AA (8.1 +/- 1.7%) (n = 5). HPLC analysis revealed unmetabolized /sup 3/H-AA, /sup 3/H-LTC/sub 4/, /sup 3/H-HETE and an unidentified peak which migrated in the prostaglandin region of the elution profile. The same metabolites were released when the basophils were challenged with antigen. The calcium ionophore A23187 (1..mu..g/ml) also caused the release of histamine (37.4 +/- 4.1%) and /sup 3/H-AA (17.0 +/- 2.9%), while the phorbol ester, TPA caused HR (19.7 +/- 5.8%) but no increase in /sup 3/H AA turnover. Because of limited cell numbers this is the first time the authors have been able to study AA metabolism in human basophils.

  18. Absorption and metabolism of orally fed arachidonic and linoleic acid in the rat

    SciTech Connect

    Nilsson, A.; Melin, T. )

    1988-11-01

    ({sup 3}H)arachidonic (({sup 3}H)20:4) and ({sup 14}C)linoleic acid ({sup 14}C)18:2 were fed to rats in Intralipid or cream. Later (30-240 min) the stomach, small intestine, plasma, and liver were analyzed for radioactivity in different lipid classes. ({sup 3}H)20:4 and ({sup 14}C)18:2 were emptied from the stomach and absorbed by the intestine at similar rates. The ({sup 3}H)20:4:({sup 14}C)18:2 ratio of the lipids in the small intestinal wall increased, however, with time. This was due to a higher retention of ({sup 3}H)20:4 than ({sup 14}C)18:2 in intestinal phospholipids. In contrast, more of the ({sup 14}C)18:2 was in triacylglycerol of the small intestine and plasma. The highest {sup 3}H:{sup 14}C ratios were found in phosphatidylethanolamine and phosphatidylinositol. The {sup 3}H:{sup 14}C ratio of intestinal phosphatidylcholine varied with the type of fat vehicle used, being highest in the Intralipid experiments. After feeding Intralipid (30-60 min), significantly more of the plasma ({sup 3}H)20:4 than plasma ({sup 14}C)18:2 was in diacylglycerol, the {sup 3}H:{sup 14}C ratio of which was much higher than that of plasma free fatty acids. ({sup 3}H)20:4 and ({sup 14}C)18:2 of chyle triacylglycerol are thus metabolized differently.

  19. Arachidonic acid-derived signaling lipids and functions in impaired healing

    PubMed Central

    Dhall, Sandeep; Wijesinghe, Dayanjan Shanaka; Karim, Zubair A.; Castro, Anthony; Vemana, Hari Priya; Khasawneh, Fadi T.; Chalfant, Charles E.; Martins-Green, Manuela

    2016-01-01

    Very little is known about lipid function during wound healing, and much less during impaired healing. Such understanding will help identify what roles lipid signaling plays in the development of impaired/chronic wounds. We took a lipidomics approach to study the alterations in lipid profile in the LIGHT−/− mouse model of impaired healing which has characteristics that resemble those of impaired/chronic wounds in humans, including high levels of oxidative stress, excess inflammation, increased extracellular matrix degradation and blood vessels with fibrin cuffs. The latter suggests excess coagulation and potentially increased platelet aggregation. We show here that in these impaired wounds there is an imbalance in the arachidonic acid (AA) derived eicosonoids that mediate or modulate inflammatory reactions and platelet aggregation. In the LIGHT−/− impaired wounds there is a significant increase in enzymatically derived breakdown products of AA. We found that early after injury there was a significant increase in the eicosanoids 11-, 12-, and 15-hydroxyeicosa-tetranoic acid, and the proinflammatory leukotrienes (LTD4 and LTE) and prostaglandins (PGE2 and PGF2α). Some of these eicosanoids also promote platelet aggregation. This led us to examine the levels of other eicosanoids known to be involved in the latter process. We found that thromboxane (TXA2/B2), and prostacyclins 6kPGF1α are elevated shortly after wounding and in some cases during healing. To determine whether they have an impact in platelet aggregation and hemostasis, we tested LIGHT−/− mouse wounds for these two parameters and found that, indeed, platelet aggregation and hemostasis are enhanced in these mice when compared with the control C57BL/6 mice. Understanding lipid signaling in impaired wounds can potentially lead to development of new therapeutics or in using existing nonsteroidal anti-inflammatory agents to help correct the course of healing. PMID:26135854

  20. Extracts from Tribulus species may modulate platelet adhesion by interfering with arachidonic acid metabolism.

    PubMed

    Olas, Beata; Hamed, Arafa I; Oleszek, Wieslaw; Stochmal, Anna

    2015-01-01

    The present work was designed to study the effects of crude extracts from Tribulus pterocarpus, T. pentandrus and T. parvispinus on selected biological functions of human blood platelets in vitro. Platelet suspensions were pre-incubated with extracts from aerial parts of T. pterocarpus, T. pentandrus and T. parvispinus, at the final concentrations of 0.5, 5 and 50 µg/ml. Then, for platelet activation thrombin, was used. The effects of crude extracts from T. pterocarpus, T. pentandrus and T. parvispinus on adhesion of blood platelets to collagen were determined by method according to Tuszynski and Murphy. Arachidonic acid metabolism was measured by the level of thiobarbituric acid reactive substances (TBARS). In these studies we also compared the action of tested crude plant extracts with the effects of the polyphenolic fraction isolated from aerial parts of T. pterocarpus, which has antiplatelet and antioxidative properties. The performed assays demonstrated that the tested crude extract from T. pterocarpus and the phenolic fraction from T. pterocarpus might influence the platelet functions in vitro. The inhibitory, concentration-dependent effects of this tested extract and its phenolic fraction on adhesion of resting platelets and thrombin - stimulated platelets to collagen was found. We also observed that the crude extract from T. pterocarpus, like the polyphenolic fraction from T. pterocarpus reduced TBARS production in blood platelets. In the comparative studies, the tested crude extract from T. pterocarpus was not found to be more effective antiplatelet factor, than the polyphenolic fraction from this plant. The results obtained suggest that T. pterocarpus may be a promising source of natural compounds, valuable in the prevention of the enhanced activity of blood platelets in numerous cardiovascular diseases.

  1. Mechanism of arachidonic acid liberation in platelet-activating factor-stimulated human polymorphonuclear neutrophils

    SciTech Connect

    Nakashima, S.; Suganuma, A.; Sato, M.; Tohmatsu, T.; Nozawa, Y. )

    1989-08-15

    Upon stimulation of human polymorphonuclear neutrophils with platelet-activating factor (PAF), arachidonic acid (AA) is released from membrane phospholipids. The mechanism for AA liberation, a key step in the synthesis of biologically active eicosanoids, was investigated. PAF was found to elicit an increase in the cytoplasmic level of free Ca2+ as monitored by fluorescent indicator fura 2. When (3H) AA-labeled neutrophils were exposed to PAF, the enhanced release of AA was observed with a concomitant decrease of radioactivity in phosphatidylinositol and phosphatidylcholine fractions. The inhibitors of phospholipase A2, mepacrine and 2-(p-amylcinnamoyl)-amino-4-chlorobenzoic acid, effectively suppressed the liberation of (3H)AA from phospholipids, indicating that liberation of AA is mainly catalyzed by the action of phospholipase A2. The extracellular Ca2+ is not required for AA release. However, intracellular Ca2+ antagonists, TMB-8 and high dose of quin 2/AM drastically reduced the liberation of AA induced by PAF, indicating that Ca2+ is an essential factor for phospholipase A2 activation. PAF raised the fluorescence of fura 2 at concentrations as low as 8 pM which reached a maximal level about 8 nM, whereas more than nM order concentrations of PAF was required for the detectable release of (3H)AA. Pretreatment of neutrophils with pertussis toxin resulted in complete abolition of AA liberation in response to PAF. However, the fura 2 response to PAF was not effectively inhibited by toxin treatment. In human neutrophil homogenate and membrane preparations, guanosine 5'-O-(thiotriphosphate) stimulated AA release and potentiated the action of PAF. Guanosine 5'-O-(thiodiphosphate) inhibited the effects of guanosine 5'-O-(thiotriphosphate).

  2. Fatty acid transfer in the food web of a coastal Mediterranean lagoon: Evidence for high arachidonic acid retention in fish

    NASA Astrophysics Data System (ADS)

    Koussoroplis, Apostolos-Manuel; Bec, Alexandre; Perga, Marie-Elodie; Koutrakis, Emmanuil; Bourdier, Gilles; Desvilettes, Christian

    2011-02-01

    The transfer of fatty acids (FAs) in the food web of a Mediterranean lagoon was studied using FA compositional patterns across several trophic levels. The structure of the food web was inferred from C and N stable isotopes values and an isotope mixing model was used in order to estimate the relative contribution of the different potential food sources to the biomass of consumers. Bidimensional plots of FA composition of food web components against their δ 15N values indicated a general trend of increasing proportions of highly unsaturated fatty acids (HUFAs) with increasing trophic levels while the proportions of saturated fatty acids (SAFAs) and 18-carbon polyunsaturated fatty acids (PUFAs) decreased. Using the relative contributions of food sources to consumers and their FA compositions, a model was built in order to estimate the PUFA composition of consumer mixed diets which was compared to consumer PUFA profiles. The latter allowed the identification of the PUFAs which were mostly enriched/retained in consumer lipids. There was a surprisingly high retention of arachidonic acid (ARA), a trend which challenges the idea of low ARA needs in marine fish and suggests the important physiological role of this essential FA for fish in estuarine environments.

  3. Chemical nature and immunotoxicological properties of arachidonic acid degradation products formed by exposure to ozone.

    PubMed Central

    Madden, M C; Friedman, M; Hanley, N; Siegler, E; Quay, J; Becker, S; Devlin, R; Koren, H S

    1993-01-01

    Ozone (O3) exposure in vivo has been reported to degrade arachidonic acid (AA) in the lungs of rodents. The O3-degraded AA products may play a role in the responses to this toxicant. To study the chemical nature and biological activity of O3-exposed AA, we exposed AA in a cell-free, aqueous environment to air, 0.1 ppm O3, or 1.0 ppm O3 for 30-120 min. AA exposed to air was not degraded. All O3 exposures degraded > 98% of the AA to more polar products, which were predominantly aldehydic substances (as determined by reactivity with 2,4-dinitrophenylhydrazine and subsequent separation by HPLC) and hydrogen peroxide. The type and amount of aldehydic substances formed depended on the O3 concentration and exposure duration. A human bronchial epithelial cell line (BEAS-2B, S6 subclone) exposed in vitro to either 0.1 ppm or 1.0 ppm O3 for 1 hr produced AA-derived aldehydic substances, some of which eluted with similar retention times as the aldehydic substances derived from O3 degradation of AA in the cell-free system. In vitro, O3-degraded AA induced an increase in human peripheral blood polymorphonuclear leukocyte (PMN) polarization, decreased human peripheral blood T-lymphocyte proliferation in response to mitogens, and decreased human peripheral blood natural killer cell lysis of K562 target cells. The aldehydic substances, but not hydrogen peroxide, appeared to be the principal active agents responsible for the observed effects. O3-degraded AA may play a role in the PMN influx into lungs and in decreased T-lymphocyte mitogenesis and natural killer cell activity observed in humans and rodents exposed to O3. PMID:8354202

  4. Immunopathogenesis of HIV infection in cocaine users: role of arachidonic acid.

    PubMed

    Samikkannu, Thangavel; Rao, Kurapati V K; Ding, Hong; Agudelo, Marisela; Raymond, Andrea D; Yoo, Changwon; Nair, Madhavan P N

    2014-01-01

    Arachidonic acid (AA) is known to be increased in HIV infected patients and illicit drug users are linked with severity of viral replication, disease progression, and impaired immune functions. Studies have shown that cocaine accelerates HIV infection and disease progression mediated by immune cells. Dendritic cells (DC) are the first line of antigen presentation and defense against immune dysfunction. However, the role of cocaine use in HIV associated acceleration of AA secretion and its metabolites on immature dendritic cells (IDC) has not been elucidated yet. The aim of this study is to elucidate the mechanism of AA metabolites cyclooxygenase-2 (COX-2), prostaglandin E2 synthetase (PGE2), thromboxane A2 receptor (TBXA2R), cyclopentenone prostaglandins (CyPG), such as 15-deoxy-Δ12,14-PGJ2 (15d-PGJ2), 14-3-3 ζ/δ and 5-lipoxygenase (5-LOX) mediated induction of IDC immune dysfunctions in cocaine using HIV positive patients. The plasma levels of AA, PGE2, 15d-PGJ2, 14-3-3 ζ/δ and IDC intracellular COX-2 and 5-LOX expression were assessed in cocaine users, HIV positive patients, HIV positive cocaine users and normal subjects. Results showed that plasma concentration levels of AA, PGE2 and COX-2, TBXA2R and 5-LOX in IDCs of HIV positive cocaine users were significantly higher whereas 15d-PGJ2 and 14-3-3 ζ/δ were significantly reduced compared to either HIV positive subjects or cocaine users alone. This report demonstrates that AA metabolites are capable of mediating the accelerative effects of cocaine on HIV infection and disease progression.

  5. Reciprocal Regulation of TREK-1 Channels by Arachidonic Acid and CRH in Mouse Corticotropes

    PubMed Central

    Lee, Andy K.; Smart, James L.; Rubinstein, Marcelo; Low, Malcolm J.

    2011-01-01

    Arachidonic acid (AA) is generated in the anterior pituitary gland upon stimulation by the ACTH secretagogue, CRH. Using the patch clamp technique, we examined the action of AA on the excitability of single pituitary corticotropes obtained from a transgenic mouse strain that expresses the enhanced green fluorescent protein driven by the proopiomelanocortin promoter. CRH evoked depolarization, but AA caused hyperpolarization. Under voltage clamp condition, AA caused a rapid inhibition of the delayed rectifier K+ current and then increased a background K+ current. Inhibition of AA metabolism did not prevent the activation of the K+ current by AA, suggesting a direct action of AA. The sensitivity of the AA-activated K+ current to fluoxetine, chlorpromazine, extracellular acidification, diphenylbutylpiperidine antipsychotics, and the membrane permeable cAMP analog [8-(4-chlorophenylthio)-cAMP] suggest that the current is mediated via TWIK-related K+ channel (TREK)-1 channels. Activation of the CRH receptors that are coupled to the adenylate cyclase pathway suppressed the activation of TREK-1 current by AA and reversed the AA-mediated hyperpolarization. Intracellular acidification (pH 7.0) increased the basal amplitude of TREK-1 current and resulted in hyperpolarizaton. CRH suppressed the basal TREK-1 current in cells with intracellular acidification and caused depolarization. Our finding indicates that TREK-1 channels are important in setting the resting potential in corticotropes. The opposing actions of CRH and AA on the excitability of corticotropes raise the possibility that AA may act as a negative feedback regulator to reduce the stimulatory action of CRH and thus prevent excessive ACTH release during chronic stress. PMID:21343252

  6. Reciprocal regulation of TREK-1 channels by arachidonic acid and CRH in mouse corticotropes.

    PubMed

    Lee, Andy K; Smart, James L; Rubinstein, Marcelo; Low, Malcolm J; Tse, Amy

    2011-05-01

    Arachidonic acid (AA) is generated in the anterior pituitary gland upon stimulation by the ACTH secretagogue, CRH. Using the patch clamp technique, we examined the action of AA on the excitability of single pituitary corticotropes obtained from a transgenic mouse strain that expresses the enhanced green fluorescent protein driven by the proopiomelanocortin promoter. CRH evoked depolarization, but AA caused hyperpolarization. Under voltage clamp condition, AA caused a rapid inhibition of the delayed rectifier K(+) current and then increased a background K(+) current. Inhibition of AA metabolism did not prevent the activation of the K(+) current by AA, suggesting a direct action of AA. The sensitivity of the AA-activated K(+) current to fluoxetine, chlorpromazine, extracellular acidification, diphenylbutylpiperidine antipsychotics, and the membrane permeable cAMP analog [8-(4-chlorophenylthio)-cAMP] suggest that the current is mediated via TWIK-related K(+) channel (TREK)-1 channels. Activation of the CRH receptors that are coupled to the adenylate cyclase pathway suppressed the activation of TREK-1 current by AA and reversed the AA-mediated hyperpolarization. Intracellular acidification (pH 7.0) increased the basal amplitude of TREK-1 current and resulted in hyperpolarizaton. CRH suppressed the basal TREK-1 current in cells with intracellular acidification and caused depolarization. Our finding indicates that TREK-1 channels are important in setting the resting potential in corticotropes. The opposing actions of CRH and AA on the excitability of corticotropes raise the possibility that AA may act as a negative feedback regulator to reduce the stimulatory action of CRH and thus prevent excessive ACTH release during chronic stress.

  7. The 5-lipoxygenase inhibitor, zileuton, suppresses prostaglandin biosynthesis by inhibition of arachidonic acid release in macrophages

    PubMed Central

    Rossi, A; Pergola, C; Koeberle, A; Hoffmann, M; Dehm, F; Bramanti, P; Cuzzocrea, S; Werz, O; Sautebin, L

    2010-01-01

    BACKGROUND AND PURPOSE Zileuton is the only 5-lipoxygenase (5-LOX) inhibitor marketed as a treatment for asthma, and is often utilized as a selective tool to evaluate the role of 5-LOX and leukotrienes. The aim of this study was to investigate the effect of zileuton on prostaglandin (PG) production in vitro and in vivo. EXPERIMENTAL APPROACH Peritoneal macrophages activated with lipopolysaccharide (LPS)/interferon γ (LPS/IFNγ), J774 macrophages and human whole blood stimulated with LPS were used as in vitro models and rat carrageenan-induced pleurisy as an in vivo model. KEY RESULTS Zileuton suppressed PG biosynthesis by interference with arachidonic acid (AA) release in macrophages. We found that zileuton significantly reduced PGE2 and 6-keto prostaglandin F1α (PGF1α) levels in activated mouse peritoneal macrophages and in J774 macrophages. This effect was not related to 5-LOX inhibition, because it was also observed in macrophages from 5-LOX knockout mice. Notably, zileuton inhibited PGE2 production in LPS-stimulated human whole blood and suppressed PGE2 and 6-keto PGF1α pleural levels in rat carrageenan-induced pleurisy. Interestingly, zileuton failed to inhibit the activity of microsomal PGE2 synthase1 and of cyclooxygenase (COX)-2 and did not affect COX-2 expression. However, zileuton significantly decreased AA release in macrophages accompanied by inhibition of phospholipase A2 translocation to cellular membranes. CONCLUSIONS AND IMPLICATION Zileuton inhibited PG production by interfering at the level of AA release. Its mechanism of action, as well as its use as a pharmacological tool, in experimental models of inflammation should be reassessed. PMID:20880396

  8. Chemical nature and immunotoxicological properties of arachidonic acid degradation products formed by exposure to ozone

    SciTech Connect

    Madden, M.C.; Friedman, M.; Hanley, N.; Siegler, E.; Quay, J.; Becker, S.; Devlin, R.; Koren, H.S. )

    1993-06-01

    Ozone (O3) exposure in vivo has been reported to degrade arachidonic acid (AA) in the lungs of rodents. The O3-degraded AA products may play a role in the responses to this toxicant. To study the chemical nature and biological activity of O3-exposed AA, we exposed AA in a cell-free, aqueous environment to air, 0.1 ppm O3, or 1.0 ppm O3 for 30-120 min. AA exposed to air was not degraded. All O3 exposures degraded > 98% of the AA to more polar products, which were predominantly aldehydic substances (as determined by reactivity with 2,4-dinitrophenylhydrazine and subsequent separation by HPLC) and hydrogen peroxide. The type and amount of aldehydic substances formed depended on the O3 concentration and exposure duration. A human bronchial epithelial cell line (BEAS-2B, S6 subclone) exposed in vitro to either 0.1 ppm or 1.0 ppm O3 for 1 hr produced AA-derived aldehydic substances, some of which eluted with similar retention times as the aldehydic substances derived from O3 degradation of AA in the cell-free system. In vitro, O3-degraded AA induced an increase in human peripheral blood polymorphonuclear leukocyte (PMN) polarization, decreased human peripheral blood T-lymphocyte proliferation in response to mitogens, and decreased human peripheral blood natural killer cell lysis of K562 target cells. The aldehydic substances, but not hydrogen peroxide, appeared to be the principal active agents responsible for the observed effects. O3-degraded AA may play a role in the PMN influx into lungs and in decreased T-lymphocyte mitogenesis and natural killer cell activity observed in humans and rodents exposed to O3.

  9. Lipid Body Organelles within the Parasite Trypanosoma cruzi: A Role for Intracellular Arachidonic Acid Metabolism

    PubMed Central

    Toledo, Daniel A. M.; Roque, Natália R.; Teixeira, Lívia; Milán-Garcés, Erix A.; Carneiro, Alan B.; Almeida, Mariana R.; Andrade, Gustavo F. S.; Martins, Jefferson S.; Pinho, Roberto R.; Freire-de-Lima, Célio G.; Bozza, Patrícia T.; D’Avila, Heloisa

    2016-01-01

    Most eukaryotic cells contain varying amounts of cytosolic lipidic inclusions termed lipid bodies (LBs) or lipid droplets (LDs). In mammalian cells, such as macrophages, these lipid-rich organelles are formed in response to host-pathogen interaction during infectious diseases and are sites for biosynthesis of arachidonic acid (AA)-derived inflammatory mediators (eicosanoids). Less clear are the functions of LBs in pathogenic lower eukaryotes. In this study, we demonstrated that LBs, visualized by light microscopy with different probes and transmission electron microscopy (TEM), are produced in trypomastigote forms of the parasite Trypanosoma cruzi, the causal agent of Chagas’ disease, after both host interaction and exogenous AA stimulation. Quantitative TEM revealed that LBs from amastigotes, the intracellular forms of the parasite, growing in vivo have increased size and electron-density compared to LBs from amastigotes living in vitro. AA-stimulated trypomastigotes released high amounts of prostaglandin E2 (PGE2) and showed PGE2 synthase expression. Raman spectroscopy demonstrated increased unsaturated lipid content and AA incorporation in stimulated parasites. Moreover, both Raman and MALDI mass spectroscopy revealed increased AA content in LBs purified from AA-stimulated parasites compared to LBs from unstimulated group. By using a specific technique for eicosanoid detection, we immunolocalized PGE2 within LBs from AA-stimulated trypomastigotes. Altogether, our findings demonstrate that LBs from the parasite Trypanosoma cruzi are not just lipid storage inclusions but dynamic organelles, able to respond to host interaction and inflammatory events and involved in the AA metabolism. Acting as sources of PGE2, a potent immunomodulatory lipid mediator that inhibits many aspects of innate and adaptive immunity, newly-formed parasite LBs may be implicated with the pathogen survival in its host. PMID:27490663

  10. Putative binding sites for arachidonic acid on the human cardiac Kv1.5 channel

    PubMed Central

    Bai, Jia‐Yu; Ding, Wei‐Guang; Kojima, Akiko; Seto, Tomoyoshi

    2015-01-01

    Background and Purpose In human heart, the Kv1.5 channel contributes to repolarization of atrial action potentials. This study examined the electrophysiological and molecular mechanisms underlying arachidonic acid (AA)‐induced inhibition of the human Kv1.5 (hKv1.5) channel. Experimental Approach Site‐directed mutagenesis was conducted to mutate amino acids that reside within the pore domain of the hKv1.5 channel. Whole‐cell patch‐clamp method was used to record membrane currents through wild type and mutant hKv1.5 channels heterologously expressed in CHO cells. Computer docking simulation was conducted to predict the putative binding site(s) of AA in an open‐state model of the Kv1.5 channel. Key Results The hKv1.5 current was minimally affected at the onset of depolarization but was progressively reduced during depolarization by the presence of AA, suggesting that AA acts as an open‐channel blocker. AA itself affected the channel at extracellular sites independently of its metabolites and signalling pathways. The blocking effect of AA was attenuated at pH 8.0 but not at pH 6.4. The blocking action of AA developed rather rapidly by co‐expression of Kvβ1.3. The AA‐induced block was significantly attenuated in H463C, T480A, R487V, I502A, I508A, V512A and V516A, but not in T462C, A501V and L510A mutants of the hKv1.5 channel. Docking simulation predicted that H463, T480, R487, I508, V512 and V516 are potentially accessible for interaction with AA. Conclusions and Implications AA itself interacts with multiple amino acids located in the pore domain of the hKv1.5 channel. These findings may provide useful information for future development of selective blockers of hKv1.5 channels. PMID:26292661

  11. Vascular lipoxygenase activity: synthesis of 15-hydroxyeicosatetraenoic acid from arachidonic acid by blood vessels and cultured vascular endothelial cells.

    PubMed

    Takayama, H; Gimbrone, M A; Schafer, A I

    1987-03-15

    Although indirect pharmacologic evidence has suggested the presence of a lipoxygenase pathway of arachidonic acid (AA) metabolism in blood vessels, direct biochemical evidence has been difficult to demonstrate. We have investigated lipoxygenase metabolism in both fresh vessel preparations and cultured vascular cells from various sources and species. Lipoxygenase-derived [3H] HETE (composed of 12-HETE, 15-HETE and 5-HETE), which was abolished by ETYA but not by aspirin, was formed when [3H]AA was incubated with fresh sections of rat aorta. Lipoxygenase activity was lost following deendothelialization. A single peak of [3H] 15-HETE was produced by cultured bovine aortic and human umbilical vein endothelial cells (EC) in response to exogenous [3H]AA or from [3H]AA released by ionophore A23187 from endogenous EC membrane phospholipid pools. Cultured bovine, rabbit or rat aorta smooth muscle cells had no detectable 15-lipoxygenase activity. [14C] Linoleic acid was converted by EC to its 15-lipoxygenase metabolite, [14C] 13-hydroxyoctadecadienoic acid. These results indicate that blood vessels from different sources and species have a 15-lipoxygenase system, and this activity resides predominantly in the endothelial cells.

  12. Pathways of arachidonic acid peroxyl radical reactions and product formation with guanine radicals.

    PubMed

    Crean, Conor; Geacintov, Nicholas E; Shafirovich, Vladimir

    2008-02-01

    Peroxyl radicals were derived from the one-electron oxidation of polyunsaturated fatty acids by sulfate radicals that were generated by the photodissociation of peroxodisulfate anions in air-equilibrated aqueous solutions. Reactions of these peroxyl and neutral guanine radicals, also generated by oxidation with sulfate radicals, were investigated by laser kinetic spectroscopy, and the guanine oxidation products were identified by HPLC and mass spectrometry methods. Sulfate radicals rapidly oxidize arachidonic (ArAc), linoleic (LnAc), and palmitoleic (PmAc) acids with similar rate constants, (2-4) x 10 (9) M (-1) s (-1). The C-centered radicals derived from the oxidation of ArAc and LnAc include nonconjugated Rn(.) ( approximately 80%) and conjugated bis-allylic Rba(.) ( approximately 20%) radicals. The latter were detectable in the absence of oxygen by their prominent, narrow absorption band at 280 nm. The Rn(.) radicals of ArAc (containing three bis-allylic sites) transform to the Rba(.) radicals via an intramolecular H-atom abstraction [rate constant (7.5 +/- 0.7) x 10 (4) s (-1)]. In contrast, the Rn(.) radicals of LnAc that contain only one bis-allylic site do not transform intramolecularly to the Rba(.) radicals. In the case of PmAc, which contains only one double bond, the Rba(.) radicals are not observed. The Rn(.) radicals of PmAc rapidly combine with oxygen with a rate constant of (3.8 +/- 0.4) x 10(9) M(-1) s(-1). The Rba(.) radicals of ArAc are less reactive and react with oxygen with a rate constant of (2.2 +/- 0.2) x 10 (8) M (-1) s (-1). The ArAc peroxyl radicals formed spontaneously eliminate superoxide radical anions [rate constant = (3.4 +/- 0.3) x 10 (4) M (-1) s (-1)]. The stable oxidative lesions derived from the 2',3',5'-tri- O-acetylguanosine or 2',3',5'-tri- O-acetyl-8-oxo-7,8-dihydroguanosine radicals and their subsequent reactions with ArAc peroxyl radicals were also investigated. The major products found were the 2,5-diamino-4 H

  13. Arachidonic acid and cancer risk: a systematic review of observational studies

    PubMed Central

    2012-01-01

    Background An n-6 essential fatty acid, arachidonic acid (ARA) is converted into prostaglandin E2, which is involved in tumour extension. However, it is unclear whether dietary ARA intake leads to cancer in humans. We thus systematically evaluated available observational studies on the relationship between ARA exposure and the risk of colorectal, skin, breast, prostate, lung, and stomach cancers. Methods We searched the PubMed database for articles published up to May 17, 2010. 126 potentially relevant articles from the initial search and 49,670 bibliographies were scrutinised to identify eligible publications by using predefined inclusion criteria. A comprehensive literature search yielded 52 eligible articles, and their reporting quality and methodological quality was assessed. Information on the strength of the association between ARA exposure and cancer risk, the dose-response relationship, and methodological limitations was collected and evaluated with respect to consistency and study design. Results For colorectal, skin, breast, and prostate cancer, 17, 3, 18, and 16 studies, respectively, were identified. We could not obtain eligible reports for lung and stomach cancer. Studies used cohort (n = 4), nested case-control (n = 12), case-control (n = 26), and cross-sectional (n = 12) designs. The number of subjects (n = 15 - 88,795), ARA exposure assessment method (dietary intake or biomarker), cancer diagnosis and patient recruitment procedure (histological diagnosis, cancer registries, or self-reported information) varied among studies. The relationship between ARA exposure and colorectal cancer was inconsistent based on ARA exposure assessment methodology (dietary intake or biomarker). Conversely, there was no strong positive association or dose-response relationship for breast or prostate cancer. There were limited numbers of studies on skin cancer to draw any conclusions from the results. Conclusions The available epidemiologic evidence is

  14. Platelet activating factor, lyso-platelet activating factor and arachidonic acid release in normal human skin and the influence of topical steroid treatment.

    PubMed Central

    Barr, R M; Lawlor, F; Judge, M R; Courtney, P; Barlow, R; Kobza Black, A; Mallet, A I; Greaves, M W

    1993-01-01

    1. Previous, in vitro, studies have established the synthesis of platelet activating factor (PAF) by the 're-modelling' pathways in which the activation of a phospholipase A2 (PLA2) enzyme catalyses the hydrolysis of an ether-acyl-phosphocholine to give concomitant release of lyso-PAF, the immediate precursor of PAF, and arachidonic acid, the precursor of the icosanoids. The aim of this study was to investigate the relationship between PAF and eicosanoid release in human skin, and to study the effect of treatment of skin with a topical steroid, on the release of PAF, lyso-PAF and arachidonic acid. 2. A novel assay procedure was developed for the simultaneous assay of PAF and lyso-PAF in skin exudates from abrasions and suction blisters in normal human skin. In addition we assayed arachidonic acid and prostaglandin E2 (PGE2), a representative eicosanoid. 3. The mean amounts of mediator recovered in the first 30 min period following abrasion were PAF 0.43, lyso-PAF 11.9, PGE2 25.7 and arachidonic acid 760 pmol/sample. The molar ratio of PAF:lyso-PAF:arachidonic acid in skin exudates from abrasions was 1:30:1800 and in suction blister exudates was 1:90:3660. 4. Time course studies showed a decline in the recoveries of arachidonic acid and lyso-PAF, of about 50% in 2 h. In contrast, PAF was recovered in exudates at a constant rate over 2 h but PGE2 release decreased by more than 90% after the initial 30 min period. 5. Topical application under occlusion, of 0.05% clobetasol propionate, a potent corticosteroid, significantly reduced lyso-PAF by 30% in suction blister exudates but did not significantly alter the concentrations of PAF or arachidonic acid.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8329291

  15. Retroconversion of docosapentaenoic acid (n-6): an alternative pathway for biosynthesis of arachidonic acid in Daphnia magna.

    PubMed

    Strandberg, Ursula; Taipale, Sami J; Kainz, Martin J; Brett, Michael T

    2014-06-01

    The aim of this study was to assess metabolic pathways for arachidonic acid (20:4n-6) biosynthesis in Daphnia magna. Neonates of D. magna were maintained on [(13)C] enriched Scenedesmus obliquus and supplemented with liposomes that contained separate treatments of unlabeled docosapentaenoic acid (22:5n-6), 20:4n-6, linoleic acid (18:2n-6) or oleic acid (18:1n-9). Daphnia in the control treatment, without any supplementary fatty acids (FA) containing only trace amounts of 20:4n-6 (~0.3% of all FA). As expected, the highest proportion of 20:4n-6 (~6.3%) was detected in Daphnia that received liposomes supplemented with this FA. Higher availability of 18:2n-6 in the diet increased the proportion of 18:2n-6 in Daphnia, but the proportion of 20:4n-6 was not affected. Daphnia supplemented with 22:5n-6 contained ~3.5% 20:4n-6 in the lipids and FA specific stable isotope analyses validated that the increase in the proportion of 20:4n-6 was due to retroconversion of unlabeled 22:5n-6. These results suggest that chain shortening of 22:5n-6 is a more efficient pathway to synthesize 20:4n-6 in D. magna than elongation and desaturation of 18:2n-6. These results may at least partially explain the discrepancies noticed between phytoplankton FA composition and the expected FA composition in freshwater cladocerans. Finally, retroconversion of dietary 22:5n-6 to 20:4n-6 indicates Daphnia efficiently retain long chain n-6 FA in lake food webs, which might be important for the nutritional ecology of fish.

  16. The influence of supplemental docosahexaenoic and arachidonic acids during pregnancy and lactation on neurodevelopment at eighteen months.

    PubMed

    van Goor, Saskia A; Dijck-Brouwer, D A Janneke; Erwich, Jan Jaap H M; Schaafsma, Anne; Hadders-Algra, Mijna

    2011-01-01

    Docosahexaenoic acid (DHA) and arachidonic acid (AA) are important for neurodevelopment. The effects of DHA (220 mg/day, n=41), DHA+AA (220 mg/day, n=39) or placebo (n=34) during pregnancy and lactation on neurodevelopment at 18 months, and the relations between umbilical cord DHA, AA and Mead acid and neurodevelopment were studied. An age-specific, standardized neurological assessment for the evaluation of minor neurological dysfunction (MND), and the Bayley Scales of Infant Development (BSID) were used. The intervention did not influence any of the outcomes. Umbilical venous (UV) Mead acid was negatively and n-6 fatty acids were weakly positively associated to the BSID mental developmental index. Children with simple MND had lower UV DHA compared to normally classified children. We conclude that relatively short-term maternal DHA or DHA+AA supplementation does not influence neurodevelopment at toddler age, although some parameters of brain development are related to perinatal DHA and AA status.

  17. The influence of long chain polyunsaturate supplementation on docosahexaenoic acid and arachidonic acid in baboon neonate central nervous system

    PubMed Central

    Diau, Guan-Yeu; Hsieh, Andrea T; Sarkadi-Nagy, Eszter A; Wijendran, Vasuki; Nathanielsz, Peter W; Brenna, J Thomas

    2005-01-01

    Background Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are major components of the cerebral cortex and visual system, where they play a critical role in neural development. We quantitatively mapped fatty acids in 26 regions of the four-week-old breastfed baboon CNS, and studied the influence of dietary DHA and ARA supplementation and prematurity on CNS DHA and ARA concentrations. Methods Baboons were randomized into a breastfed (B) and four formula-fed groups: term, no DHA/ARA (T-); term, DHA/ARA supplemented (T+); preterm, no DHA/ARA (P-); preterm and DHA/ARA supplemented (P+). At four weeks adjusted age, brains were dissected and total fatty acids analyzed by gas chromatography and mass spectrometry. Results DHA and ARA are rich in many more structures than previously reported. They are most concentrated in structures local to the brain stem and diencephalon, particularly the basal ganglia, limbic regions, thalamus and midbrain, and comparatively lower in white matter. Dietary supplementation increased DHA in all structures but had little influence on ARA concentrations. Supplementation restored DHA concentrations to levels of breastfed neonates in all regions except the cerebral cortex and cerebellum. Prematurity per se did not exert a strong influence on DHA or ARA concentrations. Conclusion 1) DHA and ARA are found in high concentration throughout the primate CNS, particularly in gray matter such as basal ganglia; 2) DHA concentrations drop across most CNS structures in neonates consuming formulas with no DHA, but ARA levels are relatively immune to ARA in the diet; 3) supplementation of infant formula is effective at restoring DHA concentration in structures other than the cerebral cortex. These results will be useful as a guide to future investigations of CNS function in the absence of dietary DHA and ARA. PMID:15975147

  18. n-Hexanal and (Z)-3-hexenal are generated from arachidonic acid and linolenic acid by a lipoxygenase in Marchantia polymorpha L.

    PubMed

    Tawfik, Moataz M; Yamato, Katsuyuki T; Kohchi, Takayuki; Koeduka, Takao; Matsui, Kenji

    2017-02-06

    Most terrestrial plants form green leaf volatiles (GLVs), which are mainly composed of six-carbon (C6) compounds. In our effort to study the distribution of the ability of lipoxygenase (LOX) to form GLVs, we found that a liverwort, Marchantia polymorpha, formed n-hexanal and (Z)-3-hexenal. Some LOXs execute a secondary reaction to form short chain volatiles. One of the LOXs from M. polymorpha (MpLOX7) oxygenized arachidonic and α-linolenic acids at almost equivalent efficiency and formed C6-aldehydes during its catalysis; these are likely formed from hydroperoxides of arachidonic and α-linolenic acids, with a cleavage of the bond between carbon at the base of the hydroperoxy group and carbon of double bond, which is energetically unfavorable. These lines of evidence suggest that one of the LOXs in liverwort employs an unprecedented reaction to form C6 aldehydes as by-products of its reaction with fatty acid substrates.

  19. Swelling-activated and arachidonic acid-induced currents are TREK-1 in rat bladder smooth muscle cells

    PubMed Central

    Fukasaku, Mitsuko; Kimura, Junko; Yamaguchi, Osamu

    2016-01-01

    Abstract Using the perforated patch voltage clamp, we investigated swelling-activated ionic channels (SACs) in rat urinary bladder smooth muscle cells. Hypo-osmotic (60%) bath solution increased a membrane current which was inhibited by the SAC inhibitor, gadolinium. The reversal potential of the hypotonicity-induced current shifted in the positive direction by increasing external K+ concentration. The hypotonicity-induced current was inhibited by extracellular acidic pH, phorbol ester and forskolin. These pharmacological properties are identical to those of arachidonic acid-induced current present in these cells, suggesting the presence of TREK-1, a four-transmembrane two pore domain K+ channel. Using RT-PCR we screened rat bladder smooth muscles and cerebellum for expression of TREK-1, TREK-2 and TRAAK mRNAs. Only TREK-1 mRNA was expressed in the bladder, while all three were expressed in the cerebellum. We conclude that a mechanosensitive K+ channel is present in rat bladder myocytes, which is activated by arachidonic acid and most likely is TREK-1. This K+ channel may have an important role in the regulation of bladder smooth muscle tone during urine storage. PMID:26911303

  20. Swelling-activated and arachidonic acid-induced currents are TREK-1 in rat bladder smooth muscle cells.

    PubMed

    Fukasaku, Mitsuko; Kimura, Junko; Yamaguchi, Osamu

    2016-06-08

    Using the perforated patch voltage clamp, we investigated swelling-activated ionic channels (SACs) in rat urinary bladder smooth muscle cells. Hypo-osmotic (60%) bath solution increased a membrane current which was inhibited by the SAC inhibitor, gadolinium. The reversal potential of the hypotonicity-induced current shifted in the positive direction by increasing external K(+) concentration. The hypotonicity-induced current was inhibited by extracellular acidic pH, phorbol ester and forskolin. These pharmacological properties are identical to those of arachidonic acid-induced current present in these cells, suggesting the presence of TREK-1, a four-transmembrane two pore domain K(+) channel. Using RT-PCR we screened rat bladder smooth muscles and cerebellum for expression of TREK-1, TREK-2 and TRAAK mRNAs. Only TREK-1 mRNA was expressed in the bladder, while all three were expressed in the cerebellum. We conclude that a mechanosensitive K(+) channel is present in rat bladder myocytes, which is activated by arachidonic acid and most likely is TREK-1. This K(+) channel may have an important role in the regulation of bladder smooth muscle tone during urine storage.

  1. Migration of human inflammatory cells into the lung results in the remodeling of arachidonic acid into a triglyceride pool

    PubMed Central

    1995-01-01

    Increasing evidence suggests that the metabolism of arachidonic acid (AA) may be different in inflammatory cells isolated from blood or migrating into tissues. To explore the possibility that changes in AA metabolism between blood and tissue inflammatory cells could be due in part to a different content or distribution of AA in glycerolipid classes, we studied these parameters in six human inflammatory cells isolated from blood (eosinophils, monocytes, neutrophils, and platelets) or from the lung tissue (mast cells and macrophages). Lung cells generally had a higher total cellular content of AA than that found in the blood cells. In addition, both mast cells and macrophages had a large endogenous pool of AA associated with triglycerides (TG), containing 45 and 22% of their total cellular AA, respectively. To address the hypothesis that cells migrating into the lung had a higher cellular level of AA and a larger AA pool in TG, we studied neutrophils isolated from the bronchoalveolar lavage (BAL) of patients with adult respiratory distress syndrome. BAL neutrophils had a fourfold increase in cellular AA as compared with blood neutrophils and contained 25% of their AA in TG versus 3% in blood neutrophils. BAL neutrophils also had a higher number of cytoplasmic lipid bodies (8 +/- 3/cell) relative to blood neutrophils (2 +/- 1/cell). High concentrations of free AA were also found in the cell-free BAL fluid of adult respiratory distress syndrome patients. To explore whether changes in BAL neutrophils may be due to the exposure of the cells to high concentrations of exogenous AA found in BAL, we incubated blood neutrophils in culture with AA (10-100 microM) for 24 h. Neutrophils supplemented with AA had a 10-fold increase in the amount of AA associated with TG and a sixfold increase in the number of lipid bodies. In addition, supplementation with AA induced a dose-dependent formation of hypodense cells. Taken together, these data indicate that human inflammatory cells

  2. Elevated ratio of arachidonic acid to long-chain omega-3 fatty acids predicts depression development following interferon-alpha treatment: relationship with interleukin-6.

    PubMed

    Lotrich, Francis E; Sears, Barry; McNamara, Robert K

    2013-07-01

    Cross-sectional studies have found that an elevated ratio of arachidonic acid to omega-3 fatty acid is associated with depression, and controlled intervention studies have found that decreasing this ratio through administration of omega-3 fatty acids can alleviate depressive symptoms. Additionally, arachidonic acid and omega-3 fatty acids have opposing effects on inflammatory signaling. Exogenous administration of the inflammatory cytokine interferon-alpha (IFN-α) can trigger a depressive episode in a subset of vulnerable people, though associated risk factors remain poorly understood. Using a within-subject prospective design of 138 subjects, we examined whether baseline long-chain omega-3 (docosahexaenoic acid - DHA; eicosapentaenoic acid - EPA) and omega-6 (arachidonic acid - AA; di-homo-gamma-linolenic acid - DGLA) fatty acid status was associated with depression vulnerability in hepatitis C patients treated with IFN-α. Based on the literature, we had specific a priori interest in the AA/EPA+DHA ratio. Lower baseline DHA predicted depression incidence (p=0.04), as did elevated DGLA (p=0.02) and an elevated AA/EPA+DHA ratio (p=0.007). The AA/EPA+DHA ratio predicted depression even when controlling for other critical variables such as sleep quality and race. A higher AA/EPA+DHA ratio was positively associated with both increasing Montgomery-Asperg Depression Rating Scores over time (F=4.0; p<0.05) as well as interleukin-6 levels (F=107.4; p<0.05) but not C-reactive protein. Importantly, omega-3 and omega-6 fatty acid status was not associated with sustained viral response to IFN-α treatment. These prospective data support the role of fatty acid status in depression vulnerability and indicate a potential role for omega-3 fatty acids in the prevention of inflammation-induced depression.

  3. Impact of arachidonic acid enrichment of live rotifer prey on bacterial communities in rotifer and larval fish cultures.

    PubMed

    Seychelles, Laurent H; Doiron, Kim; Audet, Céline; Tremblay, Réjean; Pernet, Fabrice; Lemarchand, Karine

    2013-03-01

    Rotifers (Brachionus plicatilis), commonly used at first feeding in commercial fish hatcheries, carry a large bacteria load. Because they are relatively poor in essential fatty acids, it is common practice to enrich them with fatty acids, including arachidonic acid (AA). This study aims to determine whether prey enrichment with AA may act as a prebiotic and modify the microbial community composition either in AA-enriched rotifer cultures or in larval-rearing water using winter flounder (Pseudopleuronectes americanus) as a larval fish model. AA enrichment modified the bacterial community composition in both the rotifer culture tanks and the larval-rearing tanks. We observed an increase in the number of cultivable bacteria on TCBS (thiosulfate-citrate-bile salts-sucrose) agar, used as a proxy for the abundance of Vibrio sp. The results suggest that AA may also play an indirect role in larval health.

  4. A Circadian Rhythm-Regulated Tomato Gene Is Induced by Arachidonic Acid and Phythophthora infestans Infection1[W

    PubMed Central

    Weyman, Philip D.; Pan, Zhiqiang; Feng, Qin; Gilchrist, David G.; Bostock, Richard M.

    2006-01-01

    A cDNA clone of unknown function, DEA1, was isolated from arachidonic acid-treated tomato (Solanum lycopersicum) leaves by differential display PCR. The gene, DEA1, is expressed in response to the programmed cell death-inducing arachidonic acid within 8 h following treatment of a tomato leaflet, 16 h prior to the development of visible cell death. DEA1 transcript levels were also affected by the late blight pathogen, Phytophthora infestans. To gain further insight into the transcriptional regulation of DEA1, the promoter region was cloned by inverse PCR and was found to contain putative stress-, signaling-, and circadian-response elements. DEA1 is highly expressed in roots, stems, and leaves, but not in flowers. Leaf expression of DEA1 is regulated by circadian rhythms during long days with the peak occurring at midday and the low point midway through the dark period. During short days, the rhythm is lost and DEA1 expression becomes constitutive. The predicted DEA1 protein has a conserved domain shared by the eight-cysteine motif superfamily of protease inhibitors, α-amylase inhibitors, seed storage proteins, and lipid transfer proteins. A DEA1-green fluorescent protein fusion protein localized to the plasma membrane in protoplasts and plasmolysis experiments, suggesting that the native protein is associated with the plasmalemma in intact cells. PMID:16361525

  5. Potential Antifungal Targets against a Candida Biofilm Based on an Enzyme in the Arachidonic Acid Cascade—A Review

    PubMed Central

    Liu, Xinning; Wang, Decai; Yu, Cuixiang; Li, Tao; Liu, Jianqiao; Sun, Shujuan

    2016-01-01

    Candida is an important opportunistic fungal pathogen, especially in biofilm associated infections. The formation of a Candida biofilm can decrease Candida sensitivity to antifungal drugs and cause drug resistance. Although many effective antifungal drugs are available, their applications are limited due to their high toxicity and cost. Seeking new antifungal agents that are effective against biofilm-associated infection is an urgent need. Many research efforts are underway, and some progress has been made in this field. It has been shown that the arachidonic acid cascade plays an important role in fungal morphogenesis and pathogenicity. Notably, prostaglandin E2 (PGE2) can promote the formation of a Candida biofilm. Recently, the inhibition of PGE2 has received much attention. Studies have shown that cyclooxygenase (COX) inhibitors, such as aspirin, ibuprofen, and indomethacin, combined with fluconazole can significantly reduce Candida adhesion and biofilm development and increase fluconazole susceptibility; the MIC of fluconazole can be decrease from 64 to 2 μg/ml when used in combination with ibuprofen. In addition, in vivo studies have also confirmed the antifungal activities of these inhibitors. In this article, we mainly review the relationship between PGE2 and Candida biofilm, summarize the antifungal activities of COX inhibitors and analyze the possible antifungal activity of microsomal prostaglandin E synthase-1 (MPGES-1) inhibitors; additionally, other factors that influence PGE2 production are also discussed. Hopefully this review can disclose potential antifungal targets based on the arachidonic acid cascade and provide a prevailing strategy to alleviate Candida albicans biofilm formation. PMID:27999568

  6. Lyso(bis)phosphatidic acid: a preferred donor of arachidonic acid for macrophage-synthesis of eicosanoids

    SciTech Connect

    Cochran, F.; Roddick, V.; Connor, J.; Waite, M.

    1986-05-01

    In order to dissect mechanisms of arachidonic acid (20:4) metabolism, two cell populations were investigated, resident (AM) and Bacillus Calmette-Guerin-activated (BCG-AM) rabbit alveolar macrophages. After purified AM were labeled overnight with (/sup 3/H)20:4, radioactivity was localized primarily within lyso(bis)phosphatidic acid (L(bis)PA) (13.1%), phosphatidylethanolamine (PE) (22.8%) and phosphatidylcholine (PC) (26.7%), with lesser amounts recovered in phosphatidyl-serine (PS) plus phosphatidylinositol (PI) (9.2%). By contrast, analysis of the phospholipid classes from prelabeled BCG-AM revealed that the mass of L(bis)PA as well as its (/sup 3/H)20:4 content was profoundly decreased while other BCG-AM phospholipids remained unchanged. When (/sup 3/H)20:4-labeled AM were stimulated with 1 ..mu..M 12-0-tetradecanoyl-phorbol-13-acetate (TPA), a loss of (/sup 3/H)20:4 was observed from L(bis)PA, PE, PC, and PS/PI with a corresponding increase in eicosanoid synthesis. BCG-AM exposed to either TPA or 3.8 ..mu..M Ca/sup +2/ ionophore A23187 liberated (/sup 3/H)20:4 solely from Pe and PC. BCG-AM, which exhibited depressed eicosanoid formation, consistently failed to deacylate (/sup 3/H)20:4 from L(bis)PA or PI. Their evidence suggests that the diminution of eicosanoid synthesis by BCG-AM may be due to the reduction of 20:4 contained within specific phospholipid pools, namely L(bis)PA.

  7. Diverse ways of perturbing the human arachidonic acid metabolic network to control inflammation.

    PubMed

    Meng, Hu; Liu, Ying; Lai, Luhua

    2015-08-18

    Inflammation and other common disorders including diabetes, cardiovascular disease, and cancer are often the result of several molecular abnormalities and are not likely to be resolved by a traditional single-target drug discovery approach. Though inflammation is a normal bodily reaction, uncontrolled and misdirected inflammation can cause inflammatory diseases such as rheumatoid arthritis and asthma. Nonsteroidal anti-inflammatory drugs including aspirin, ibuprofen, naproxen, or celecoxib are commonly used to relieve aches and pains, but often these drugs have undesirable and sometimes even fatal side effects. To facilitate safer and more effective anti-inflammatory drug discovery, a balanced treatment strategy should be developed at the biological network level. In this Account, we focus on our recent progress in modeling the inflammation-related arachidonic acid (AA) metabolic network and subsequent multiple drug design. We first constructed a mathematical model of inflammation based on experimental data and then applied the model to simulate the effects of commonly used anti-inflammatory drugs. Our results indicated that the model correctly reproduced the established bleeding and cardiovascular side effects. Multitarget optimal intervention (MTOI), a Monte Carlo simulated annealing based computational scheme, was then developed to identify key targets and optimal solutions for controlling inflammation. A number of optimal multitarget strategies were discovered that were both effective and safe and had minimal associated side effects. Experimental studies were performed to evaluate these multitarget control solutions further using different combinations of inhibitors to perturb the network. Consequently, simultaneous control of cyclooxygenase-1 and -2 and leukotriene A4 hydrolase, as well as 5-lipoxygenase and prostaglandin E2 synthase were found to be among the best solutions. A single compound that can bind multiple targets presents advantages including low

  8. Mechanism of Arachidonic Acid Accumulation during Aging in Mortierella alpina: A Large-Scale Label-Free Comparative Proteomics Study.

    PubMed

    Yu, Yadong; Li, Tao; Wu, Na; Ren, Lujing; Jiang, Ling; Ji, Xiaojun; Huang, He

    2016-11-30

    Arachidonic acid (ARA) is an important polyunsaturated fatty acid having various beneficial physiological effects on the human body. The aging of Mortierella alpina has long been known to significantly improve ARA yield, but the exact mechanism is still elusive. Herein, multiple approaches including large-scale label-free comparative proteomics were employed to systematically investigate the mechanism mentioned above. Upon ultrastructural observation, abnormal mitochondria were found to aggregate around shrunken lipid droplets. Proteomics analysis revealed a total of 171 proteins with significant alterations of expression during aging. Pathway analysis suggested that reactive oxygen species (ROS) were accumulated and stimulated the activation of the malate/pyruvate cycle and isocitrate dehydrogenase, which might provide additional NADPH for ARA synthesis. EC 4.2.1.17-hydratase might be a key player in ARA accumulation during aging. These findings provide a valuable resource for efforts to further improve the ARA content in the oil produced by aging M. alpina.

  9. Increased fatty acid unsaturation and production of arachidonic acid by homologous over-expression of the mitochondrial malic enzyme in Mortierella alpina.

    PubMed

    Hao, Guangfei; Chen, Haiqin; Du, Kai; Huang, Xiaoyun; Song, Yuanda; Gu, Zhennan; Wang, Lei; Zhang, Hao; Chen, Wei; Chen, Yong Q

    2014-09-01

    Malic enzyme (ME) catalyses the oxidative decarboxylation of L-malate to pyruvate and provides NADPH for intracellular metabolism, such as fatty acid synthesis. Here, the mitochondrial ME (mME) gene from Mortierella alpina was homologously over-expressed. Compared with controls, fungal arachidonic acid (ARA; 20:4 n-6) content increased by 60 % without affecting the total fatty acid content. Our results suggest that enhancing mME activity may be an effective mean to increase industrial production of ARA in M. alpina.

  10. Decreased arachidonic acid content and metabolism in tissues of NZB/W F1 females fed a diet containing 0. 45% dehydroisoandrosterone (DHA)

    SciTech Connect

    Matsunaga, A.; Cottam, G.L.

    1987-05-01

    A diet containing 0.45% DHA fed to NZB/W mice, a model of systemic lupus erythematosus, delays the time of onset, improves survival and decreases the formation of antibodies to ds-DNA. Essential fatty acid-deficient diets or inclusion of eicosapentaenoic acid have similar beneficial effects and led them to investigate arachidonic acid metabolism in response to feeding DHA. The arachidonic acid content of plasma cholesteryl ester decreased from 37.4 +/- 2.2 to 28.2 +/- 1.3 mg%. In total liver phospholipid the value decreased from 18.1 +/- 0.52 to 13.7 +/- 1.3 mg%, in total kidney phospholipid the value decreased from 24.10 +/- 0.87 to 20.7 +/- 0.32 mg% and in resident peritoneal macrophages the value decreased from 15.4 +/- 4.6 to 3.6 +/- 1.4 mg%. The metabolism of exogenous (1-/sup 14/C)arachidonic acid by resident peritoneal macrophages in response to Zymosan stimulation for 2 hr was examined by extraction of metabolites and separation by HPLC. Cells isolated from DHA-fed animals produced less PGE2 than controls, yet similar amounts of 6-keto PGF1..cap alpha.. were produced. Arachidonic acid metabolites have significant effects on the immune system and may be a mechanism involved in the benefits obtained by inclusion of DHA in the diet.

  11. Differences in responsiveness of intrapulmonary artery and vein to arachidonic acid: mechanism of arterial relaxation involves cyclic guanosine 3':5'-monophosphate and cyclic adenosine 3':5'-monophosphate

    SciTech Connect

    Ignarro, L.J.; Harbison, R.G.; Wood, K.S.; Wolin, M.S.; McNamara, D.B.; Hyman, A.L.; Kadowitz, P.J.

    1985-06-01

    The objective of this study was to examine the relationship between responses of bovine intrapulmonary artery and vein to arachidonic acid and cyclic nucleotide levels in order to better understand the mechanism of relaxation elicited by arachidonic acid and acetylcholine. Arachidonic acid relaxed phenylephrine-precontracted arterial rings and elevated both cyclic GMP and cyclic AMP levels in arteries with intact endothelium. In contrast, endothelium-damaged arterial rings contracted to arachidonic acid without demonstrating significant changes in cyclic nucleotide levels. Indomethacin partially inhibited endothelium-dependent relaxation and abolished cyclic AMP accumulation whereas methylene blue, a guanylate cyclase inhibitor, partially inhibited relaxation and abolished cyclic GMP accumulation in response to arachidonic acid. All vessel responses were blocked by a combination of the two inhibitors. Prostaglandin (PG) I2 relaxed arterial rings and elevated cyclic AMP levels whereas PGE2 and PGF2 alpha caused contraction, suggesting that the indomethacin-sensitive component of arachidonic acid-elicited relaxation is due to PGI2 formation and cyclic AMP accumulation. The methylene blue-sensitive component is attributed to an endothelium-dependent but cyclooxygenase-independent generation of a substance causing cyclic GMP accumulation. Intrapulmonary veins contracted to arachidonic acid with no changes in cyclic nucleotide levels and PGI2 was without effect. Homogenates of intrapulmonary artery and vein formed 6-keto-PGF1 alpha, PGF2 alpha and PGE2 from (/sup 14/C)arachidonic acid, which was inhibited by indomethacin. Thus, bovine intrapulmonary vein may not possess receptors for PGI2.

  12. The influence of dietary nucleotides and long-chain polyunsaturated fatty acids on the incorporation of [3H] arachidonic acid on experimental liver cirrhosis.

    PubMed

    Leite, L H; Moreira-Vaz, E; Rosa, G; Pereira, A C; Monteiro, C R; Medeiros, F J; Chagas, V L

    2000-09-01

    The purposes of this study were to determine: a) the incorporation of labeled [3H] arachidonic acid on the intestinal mucosa, the liver and plasma, after 1,3 and 5 hours of administration, b) preferential incorporation by different tissues, c) and the effects on experimental rats with thioacetamide-induced cirrhosis, after four weeks of a dietary supplementation with nucleotides and long-chain polyunsaturated fatty acids. 209 female Wistar rats were divided into two groups (control and TAA group). The TAA group was given 300 mg of thioacetamide/L, in their drinking water for four months. After this period, a sample of 6 rats were taken from each group and examined, to evaluate the biochemical and histological changes of the experimental model, and 36 rats were taken to determine the incorporation of radioactivity by the groups. The rest of the animals were divided into four subgroups. Each group, receiving a supplementary diet with only long-chain polyunsaturated fatty acids and/or nucleotides or neither, for 4 weeks. After four months of thioacetamide, the incorporation of the [3H] arachidonic acid showed: a) an increased within 3 h in the intestinal mucosa, b) a decreased in the liver after 3 to 5 h c) and a drastic decrease in the plasma after 3 to 5 h. With a dietary supplementation of long-chain polyunsaturated fatty acids and nucleotides combined, there was a decrease of accumulate [3H] arachidonic acid in the intestine and a increase in the liver and plasma. The simultaneous supply of dietary polyunsaturated fatty acids and nucleotides was beneficial in the reversal of abnormalities of the lipid metabolism, in this experimental model of liver cirrhosis.

  13. Heating of vegetable oils influences the activity of enzymes participating in arachidonic acid formation in Wistar rats.

    PubMed

    Stawarska, Agnieszka; Białek, Agnieszka; Tokarz, Andrzej

    2015-10-01

    Dietary intake of lipids and their fatty acids profile influence many aspects of health. Thermal processing changes the properties of edible oils and can also modify their metabolism, for example, eicosanoids formation. The aim of our study was to verify whether the activity of desaturases can be modified by lipids intake, especially by the fatty acids content. The experimental diets contained rapeseed oil, sunflower oil, and olive oil, both unheated and heated (for 10 minutes at 200 °C each time before administration), and influenced the fatty acids composition in serum and the activity of enzymes participating in arachidonic acid (AA) formation. The activity of desaturases was determined by measuring the amounts of AA formed in vitro derived from linoleic acid as determined in liver microsomes of Wistar rats. In addition, the indices of ∆(6)-desaturase (D6D) and ∆(5)-desaturase (D5D) have been determined. To realize this aim, the method of high-performance liquid chromatography has been used with ultraviolet-visible spectrophotometry detection. Diet supplementation with the oils rich in polyunsaturated fatty acids affects the fatty acids profile in blood serum and the activity of D6D and ∆(5)-desaturase in rat liver microsomes, the above activities being dependent on the kind of oil applied. Diet supplementation with heated oils has been found to increase the amount of AA produced in hepatic microsomes; and in the case of rapeseed oil and sunflower oil, it has also increased D6D activity.

  14. Contact sensitizers modulate the arachidonic acid metabolism of PMA-differentiated U-937 monocytic cells activated by LPS

    SciTech Connect

    Del Bufalo, Aurelia; Bernad, Jose; Dardenne, Christophe; Verda, Denis; Meunier, Jean Roch; Rousset, Francoise; Martinozzi-Teissier, Silvia; Pipy, Bernard

    2011-10-01

    For the effective induction of a hapten-specific T cell immune response toward contact sensitizers, in addition to covalent-modification of skin proteins, the redox and inflammatory statuses of activated dendritic cells are crucial. The aim of this study was to better understand how sensitizers modulate an inflammatory response through cytokines production and COX metabolism cascade. To address this purpose, we used the human monocytic-like U-937 cell line differentiated by phorbol myristate acetate (PMA) and investigated the effect of 6 contact sensitizers (DNCB, PPD, hydroquinone, propyl gallate, cinnamaldehyde and eugenol) and 3 non sensitizers (lactic acid, glycerol and tween 20) on the production of pro-inflammatory cytokines (IL-1{beta} and TNF-{alpha}) and on the arachidonic acid metabolic profile after bacterial lipopolysaccharide (LPS) stimulation. Our results showed that among the tested molecules, all sensitizers specifically prevent the production of PMA/LPS-induced COX-2 metabolites (PGE{sub 2,} TxB{sub 2} and PGD{sub 2}), eugenol and cinnamaldehyde inhibiting also the production of IL-1{beta} and TNF-{alpha}. We further demonstrated that there is no unique PGE{sub 2} inhibition mechanism: while the release of arachidonic acid (AA) from membrane phospholipids does not appear do be a target of modulation, COX-2 expression and/or COX-2 enzymatic activity are the major steps of prostaglandin synthesis that are inhibited by sensitizers. Altogether these results add a new insight into the multiple biochemical effects described for sensitizers. - Highlights: > We investigated how contact sensitizers modulate an inflammatory response. > We used macrophage-differentiated cell line, U-937 treated with PMA/LPS. > Sensitizers specifically inhibit the production of COX metabolites (PGE2, TxB2). > Several mechanisms of inhibition: COX-2 expression/enzymatic activity, isomerases. > New insight in the biochemical properties of sensitizers.

  15. Targeting arachidonic acid pathway to prevent programmed hypertension in maternal fructose-fed male adult rat offspring.

    PubMed

    Tain, You-Lin; Lee, Wei-Chia; Wu, Kay L H; Leu, Steve; Chan, Julie Y H

    2016-12-01

    Hypertension can be programmed in response to nutritional insults in early life. Maternal high-fructose (HF) intake induced programmed hypertension in adult male offspring, which is associated with renal programming and arachidonic acid metabolism pathway. We examined whether early treatment with a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-Deoxy-Δ(12,14)-prostagandin J2 (15dPGJ2) can prevent HF-induced programmed hypertension. Pregnant Sprague Dawley rats received regular chow or chow supplemented with fructose (60% diet by weight) during the whole period of pregnancy and lactation. Four groups of male offspring were studied: control, HF, HF+AUDA and HF+15dPGJ2. In HF+AUDA group, mother rats received AUDA 25 mg/L in drinking water during lactation. In the HF+15dPGJ2 group, male offspring received 15dPGJ2 1.5 mg/kg body weight by subcutaneous injection once daily for 1 week after birth. Rats were sacrificed at 12 weeks of age. Maternal HF-induced programmed hypertension is associated with increased renal protein level of SEH and oxidative stress, which early AUDA therapy prevents. Comparison of AUDA and 15dPGJ2 treatments demonstrated that AUDA was more effective in preventing HF-induced programmed hypertension. AUDA therapy increases angiotensin converting enzyme-2 (ACE2) protein levels and PGE2 levels in adult offspring kidney exposed to maternal HF. 15dPGJ2 therapy increases plasma asymmetric dimethylarginine (ADMA) levels and decreases L-arginine-to-ADMA ratio. Better understanding of the impact of arachidonic acid pathway, especially inhibition of SEH, on renal programming may aid in developing reprogramming strategy to prevent programmed hypertension in children exposed to antenatal HF intake.

  16. Arachidonic Acid Metabolite 19(S)-HETE Induces Vasorelaxation and Platelet Inhibition by Activating Prostacyclin (IP) Receptor

    PubMed Central

    Chennupati, Ramesh; Nüsing, Rolf M.; Offermanns, Stefan

    2016-01-01

    19(S)-hydroxy-eicosatetraenoic acid (19(S)-HETE) belongs to a family of arachidonic acid metabolites produced by cytochrome P450 enzymes, which play critical roles in the regulation of cardiovascular, renal and pulmonary functions. Although it has been known for a long time that 19(S)-HETE has vascular effects, its mechanism of action has remained unclear. In this study we show that 19(S)-HETE induces cAMP accumulation in the human megakaryoblastic leukemia cell line MEG-01. This effect was concentration-dependent with an EC50 of 520 nM, insensitive to pharmacological inhibition of COX-1/2 and required the expression of the G-protein Gs. Systematic siRNA-mediated knock-down of each G-protein coupled receptor (GPCR) expressed in MEG-01 followed by functional analysis identified the prostacyclin receptor (IP) as the mediator of the effects of 19(S)-HETE, and the heterologously expressed IP receptor was also activated by 19(S)-HETE in a concentration-dependent manner with an EC50 of 567 nM. Pretreatment of isolated murine platelets with 19(S)-HETE blocked thrombin-induced platelets aggregation, an effect not seen in platelets from mice lacking the IP receptor. Furthermore, 19(S)-HETE was able to relax mouse mesenteric artery- and thoracic aorta-derived vessel segments. While pharmacological inhibition of COX-1/2 enzymes had no effect on the vasodilatory activity of 19(S)-HETE these effects were not observed in vessels from mice lacking the IP receptor. These results identify a novel mechanism of action for the CYP450-dependent arachidonic acid metabolite 19(S)-HETE and point to the existence of a broader spectrum of naturally occurring prostanoid receptor agonists. PMID:27662627

  17. Lipoxin A4 and lipoxin B4 stimulate the release but not the oxygenation of arachidonic acid in human neutrophils: Dissociation between lipid remodeling and adhesion

    SciTech Connect

    Nigam, S.; Fiore, S.; Luscinskas, F.W.; Serhan, C.N. )

    1990-06-01

    The profiles of actions of lipoxin A4 (LXA4) and lipoxin B4 (LXB4), two lipoxygenase-derived eicosanoids, were examined with human neutrophils. At nanomolar concentrations, LXA4 and LXB4 each stimulated the release of (1-14C)arachidonic acid from esterified sources in neutrophils. Lipoxin-induced release of (1-14C)arachidonic acid was both dose- and time-dependent and was comparable to that induced by the chemotactic peptide f-met-leu-phe. Time-course studies revealed that lipoxin A4 and lipoxin B4 each induced a biphasic release of (1-14C)arachidonic acid, which was evident within seconds (5-15 sec) in its initial phase and minutes (greater than 30 sec) in the second phase. In contrast, the all-trans isomers of LXA4 and LXB4 did not provoke (1-14C)AA release. Lipoxin-induced release of arachidonic acid was inhibited by prior treatment of the cells with pertussis toxin but not by its beta-oligomers, suggesting the involvement of guaninine nucleotide-binding regulatory proteins in this event. Dual radiolabeling of neutrophil phospholipid classes with (1-14C)arachidonic acid and (3H)palmitic acid showed that phosphatidylcholine was a major source of lipoxin-induced release of (1-14C)arachidonic acid. They also demonstrated that lipoxins rapidly stimulate both formation of phosphatidic acid as well as phospholipid remodeling. Although both LXA4 and LXB4 (10(-8)-10(-6) M) stimulated the release of (1-14C)arachidonic acid, neither compound evoked its oxygenation by either the 5- or 15-lipoxygenase pathways (including the formation of LTB4, 20-COOH-LTB4, 5-HETE, or 15-HETE). LXA4 and LXB4 (10(-7) M) each stimulated the elevation of cytosolic Ca2+ as monitored with Fura 2-loaded cells, albeit to a lesser extent than equimolar concentrations of FMLP. Neither lipoxin altered the binding of (3H)LTB4 to its receptor on neutrophils.

  18. Stimulation of arachidonic acid metabolism in primary cultures of osteoblast-like cells by hormones and drugs

    SciTech Connect

    Feyen, J.H.; van der Wilt, G.; Moonen, P.; Di Bon, A.; Nijweide, P.J.

    1984-12-01

    The effects of parathyroid hormone (PTH), dihydroxycholecalciferol (1,25-(OH)2 D3), thrombin, epidermal growth factor (EGF) and 12-o-tetradecanoylphorbol-13-acetate (PMA) on the biosynthesis and release of arachidonic acid metabolites were studied in primary cultures of osteoblast-like cells isolated from 18-day-old chick embryo calvaria. Cells were labelled with (/sup 14/C)-arachidonic acid for 30 h. The radioactive eicosanoids were extracted from the cell culture media after a further 30 h stimulation period and analysed on a PRP-1 column by HPLC. The radioactive products were characterized by co-elution of (/sup 3/H) standard prostanoids. Osteoblasts showed a basal release of the prostanoids 6-keto-PGF1 alpha, TXB2, PGF2 alpha, PGE2, PGD2 and PGB2, the latter being the most abundant one. Indomethacin (10(-5) M) effectively inhibited the basal release, but not that of an as yet unidentified compound. The release of prostanoids was stimulated by PTH (2 U/ml), thrombin (0.4 NIH/ml), EGF (50 ng/ml) and PMA (25 ng/ml), the latter being by far the most potent one. 1,25-(OH)2D3 was found to slightly inhibit the prostanoid release. These results indicate: (1) primary cultures of osteoblasts synthesize several prostaglandins, thromboxane B2 and one unidentified product. (2) the action on bone of PTH and the various drugs tested may be, at least partly, mediated by an increased prostaglandin production by osteoblasts. Clearly this does not apply to 1,25-(OH)2D3.

  19. Induction of CYP1A and cyp2-mediated arachidonic acid epoxygenation and suppression of 20-hydroxyeicosatetraenoic acid by imidazole derivatives including the aromatase inhibitor vorozole.

    PubMed

    Diani-Moore, Silvia; Papachristou, Fotini; Labitzke, Erin; Rifkind, Arleen B

    2006-08-01

    Cytochrome P450 (P450) enzymes metabolize the membrane lipid arachidonic acid to stable biologically active epoxides [eicosatrienoic acids (EETs)] and 20-hydroxyeicosatetraenoic acid (20-HETE). These products have cardiovascular activity, primarily acting as vasodilators and vasoconstrictors, respectively. EET formation can be increased by the prototype CYP1A or CYP2 inducers, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or phenobarbital (PB), respectively. We report here that imidazole derivative drugs: the anthelminthics, albendazole and thiabendazole; the proton pump inhibitor, omeprazole; the thromboxane synthase inhibitor, benzylimidazole; and the aromatase (CYP19) inhibitor vorozole (R76713, racemate; and R83842, (+) enantiomer) increased hepatic microsomal EET formation in a chick embryo model. Albendazole increased EETs by transcriptional induction of CYP1A5 and the others by combined induction of CYP1A5 and CYP2H, the avian orthologs of mammalian CYP1A2 and CYP2B, respectively. All inducers increased formation of the four EET regioisomers, but TCDD and albendazole had preference for 5,6-EET and PB and omeprazole for 14,15-EET. Vorozole, benzylimidazole, and TCDD also suppressed 20-HETE formation. Vorozole was a remarkably effective and potent inducer of multiple hepatic P450s at a dose range which overlapped its inhibition of ovarian aromatase. Increased CYP1A activity in mouse Hepa 1-6 and human HepG2 cells by vorozole and other imidazole derivatives demonstrated applicability of the findings to mammalian cells. The findings suggest that changes in P450-dependent arachidonic acid metabolism may be a new source of side effects for drugs that induce CYP1A or CYP2. They demonstrate further that in vivo induction of multiple hepatic P450s produces additive increases in arachidonic acid epoxygenase activity and can occur concurrently with inhibition of ovarian aromatase activity.

  20. Lipoxygenase- and cyclooxygenase-reaction products and incorporation into glycerolipids or radiolabeled arachidonic acid in the bovine retina

    SciTech Connect

    Birkle, D.L.; Bazan, N.G.

    1984-02-01

    The metabolism of radiolabeled arachidonic acid (AA) by the intact bovine retina in vitro has been studied. Synthesis of prostaglandins (PGs) and hydroxyeicosatetraenoic acids (HETEs), and incorporation of AA into glycerolipids has been measured by reverse-phase and straight-phase high performance liquid chromatography with flow scintillation detection, and by thin-layer chromatography. AA was actively acylated into glycerolipids, particularly triglycerides, phosphatidylcholine and phosphatidylinositol. AA was also converted to the major PGs, PGF2 alpha, PGE2, PGD2, 6-keto-PGF1 alpha and TXB2, and to the lipoxygenase reaction products, 12-HETE, 5-HETE, and other monohydroxy isomers. Approximately 6% of the radiolabeled AA was converted to eicosanoids. The synthesis of HETEs was inhibited in a concentration-dependent manner (IC50 . 8.3 nM) by nordihydroguaiaretic acid (NDGA). PG synthesis was inhibited by aspirin (10 microM), indomethacin (1 microM) and NDGA (IC50 . 380 nM). Metabolism of AA via lipoxygenase, cyclooxygenase and activation-acylation was inhibited by boiling retinal tissue prior to incubation. These studies demonstrate an active system for the uptake and utilization of AA in the bovine retina, and provide the first evidence of lipoxygenase-mediated metabolism of AA, resulting in the synthesis of mono-hydroxyeicosatetraenoic acids, in the retina.

  1. Sulfur mustard-induced increase in intracellular free calcium level and arachidonic acid release from cell membrane

    SciTech Connect

    Ray, R.; Legere, R.H.; Majerus, B.J.; Petrali, J.P.

    1995-12-31

    The mechanism of action of the alkylating agent bis-(2-chloroethyl)sulfide (sulfur mustard, SM) was studied using the in thai vitro mouse neuroblastoma-rat glioma hybrid NG 108-1 S clonal p cell line model. Following 0.3 mM SM exposure, cell viability remained high (>80% of untreated control) up to 9 hr and then declined steadily to about 40% of control after 20-24 hr. During the early period of SM exposure, when there was no significant cell viability loss, the following effects were observed. The cellular glutathione level decreased 20% after 1 hr and 34% after 6 hr. Between 2 and 6 hr, there was a time-dependent increase (about 10 to 30%) in intracellular free calcium (Ca2+), which was localized to the limiting membrane of swollen endoplasmic reticula and mitochondria, to euchromatin areas of the nucleus, and to areas of the cytosol and plasma membrane. Moreover,there was also a time-dependent increase in the release of isotopically labeled arachidonic acid ((3H)AA) from cellular membranes. Increase in (3H)AA release was 28% at 3 hr and about 60-80% between 6 and 9 hr. This increase in I3HIAA release was inhibited by quinacrine (20 uM), which is a phospholipase (PLA2) inhibitor. At 16 hr after SM exposure, there was a large increase (about 200% of control) in I3HIAA release, which was coincident with a 50% loss of cell viability. These results suggest a Ca2+-mediated toxic mechanism of SM via PLA2 activation and arachidonate release.

  2. Determination of arachidonic acid by on-line solid-phase extraction HPLC with UV detection for screening of cytosolic phospholipase A2α inhibitors.

    PubMed

    Hanekamp, Walburga; Lehr, Matthias

    2012-07-01

    An on-line solid-phase extraction (SPE)-liquid chromatographic method with ultraviolet detection at 200nm for screening of inhibitors of cytosolic phospholipase A(2)α (cPLA(2)α) was developed and validated. cPLA(2)α was isolated from porcine platelets. Enzyme activity was determined by measuring the release of arachidonic acid from a phospholipid substrate using automated on-line sample clean up on a trap column followed by isocratic back-flush elution on a RP18 analytical column. While the use of a conventional RP18 column for trapping the analyte led to peak broadening only after a few runs due to pollution of the column by binding of components present in the enzyme preparation, the application of a turbulent flow column (TurboFlow Cyclone™) resulted in sharp peaks even after a plurality of injections. Interestingly, for sample introduction a turbulent flow of the mobile phase produced by high flow rates was not necessary to maintain good peak shapes. The same result could also be achieved applying low flow rates (0.5 mL/min). Several known cPLA(2)α inhibitors were used to validate the test system.

  3. Generation of Bioactive Oxylipins from Exogenously Added Arachidonic, Eicosapentaenoic and Docosahexaenoic Acid in Primary Human Brain Microvessel Endothelial Cells.

    PubMed

    Aukema, Harold M; Winter, Tanja; Ravandi, Amir; Dalvi, Siddhartha; Miller, Donald W; Hatch, Grant M

    2016-05-01

    The human blood-brain barrier (BBB) is the restrictive barrier between the brain parenchyma and the circulating blood and is formed in part by microvessel endothelial cells. The brain contains significant amounts of arachidonic acid (ARA), and docosahexaenoic acid (DHA), which potentially give rise to the generation of bioactive oxylipins. Oxylipins are oxygenated fatty acid metabolites that are involved in an assortment of biological functions regulating neurological health and disease. Since it is not known which oxylipins are generated by human brain microvessel endothelial cells (HBMECs), they were incubated for up to 30 min in the absence or presence of 0.1-mM ARA, eicosapentaenoic acid (EPA) or DHA bound to albumin (1:1 molar ratio), and the oxylipins generated were examined using high performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS). Of 135 oxylipins screened in the media, 63 were present at >0.1 ng/mL at baseline, and 95 were present after incubation with fatty acid. Oxylipins were rapidly generated and reached maximum levels by 2-5 min. While ARA, EPA and DHA each stimulated the production of oxylipins derived from these fatty acids themselves, ARA also stimulated the production of oxylipins from endogenous 18- and 20-carbon fatty acids, including α-linolenic acid. Oxylipins generated by the lipoxygenase pathway predominated both in resting and stimulated states. Oxylipins formed via the cytochrome P450 pathway were formed primarily from DHA and EPA, but not ARA. These data indicate that HBMECs are capable of generating a plethora of bioactive lipids that have the potential to modulate BBB endothelial cell function.

  4. Preparation of human milk fat substitutes from palm stearin with arachidonic and docosahexaenoic acid: combination of enzymatic and physical methods.

    PubMed

    Zou, Xiao-Qiang; Huang, Jian-Hua; Jin, Qing-Zhe; Liu, Yuan-Fa; Tao, Guan-Jun; Cheong, Ling-Zhi; Wang, Xing-Guo

    2012-09-19

    Human milk fat substitutes (HMFSs) were prepared by a two-step process, namely, Lipozyme RM IM-catalyzed acidolysis of interesterified high-melting palm stearin with fatty acids from rapeseed oil and blending of the enzymatic product with the selected oils on the basis of the calculation model. The optimum conditions for the enzymatic reaction were a mole ratio of palm stearin/fatty acids 1:10, 60 °C, 8% enzyme load (wt % of substrates), 4 h, and 3.5% water content (wt % of enzyme); the enzymatic product contained 39.6% palmitic acid (PA), 83.7% of the fatty acids at sn-2 position were PA (sn-2 PA), and the distribution probability of PA at the sn-2 position among total PA (% sn-2 PA) was 70.5%. With the fatty acid profiles of human milk fat (HMF) as a preferable goal, a physical blending model was established for the second step to guarantee the maximum addition of selected oils. Based on the model prediction, a desirable formula constituted enzymatic product/rapeseed oil/sunflower oil/palm kernel oil/algal oil/microbial oil at a mole ratio of 1:0.28:0.40:0.36:0.015:0.017, and the final product had PA content, sn-2 PA, and %sn-2 PA at 23.5, 43.1, and 61.1%, respectively. The contents of arachidonic and docosahexaenoic acids were 0.4 and 0.3%, respectively. Relying on the total and sn-2 fatty acid compositions of HMF and "deducting score" principle, the score for the similarity between the final product and HMF was scaled as 89.2, indicating the potential as a fat substitute in infant formulas.

  5. The ω6-fatty acid, arachidonic acid, regulates the conversion of white to brite adipocyte through a prostaglandin/calcium mediated pathway

    PubMed Central

    Pisani, Didier F.; Ghandour, Rayane A.; Beranger, Guillaume E.; Le Faouder, Pauline; Chambard, Jean-Claude; Giroud, Maude; Vegiopoulos, Alexandros; Djedaini, Mansour; Bertrand-Michel, Justine; Tauc, Michel; Herzig, Stephan; Langin, Dominique; Ailhaud, Gérard; Duranton, Christophe; Amri, Ez-Zoubir

    2014-01-01

    Objective Brite adipocytes are inducible energy-dissipating cells expressing UCP1 which appear within white adipose tissue of healthy adult individuals. Recruitment of these cells represents a potential strategy to fight obesity and associated diseases. Methods/Results Using human Multipotent Adipose-Derived Stem cells, able to convert into brite adipocytes, we show that arachidonic acid strongly inhibits brite adipocyte formation via a cyclooxygenase pathway leading to secretion of PGE2 and PGF2α. Both prostaglandins induce an oscillatory Ca++ signaling coupled to ERK pathway and trigger a decrease in UCP1 expression and in oxygen consumption without altering mitochondriogenesis. In mice fed a standard diet supplemented with ω6 arachidonic acid, PGF2α and PGE2 amounts are increased in subcutaneous white adipose tissue and associated with a decrease in the recruitment of brite adipocytes. Conclusion Our results suggest that dietary excess of ω6 polyunsaturated fatty acids present in Western diets, may also favor obesity by preventing the “browning” process to take place. PMID:25506549

  6. In vitro release of arachidonic acid metabolites, glutathione peroxidase, and oxygen-free radicals from platelets of asthmatic patients with and without aspirin intolerance.

    PubMed Central

    Plaza, V.; Prat, J.; Rosellò, J.; Ballester, E.; Ramis, I.; Mullol, J.; Gelpí, E.; Vives-Corrons, J. L.; Picado, C.

    1995-01-01

    BACKGROUND--An abnormal platelet release of oxygen-free radicals has been described in acetylsalicylic acid (aspirin)-induced asthma, a finding which might suggest the existence of an intrinsic, specific platelet abnormality of arachidonic acid metabolism in these patients. The objective of this study was to evaluate platelet arachidonic acid metabolism in asthmatic patients with or without intolerance to aspirin. METHODS--Thirty subjects distributed into three groups were studied: group 1, 10 healthy subjects; group 2, 10 asthmatic patients with aspirin tolerance; and group 3, 10 aspirin-intolerant asthmatics. Platelets were isolated from blood, preincubated with 3H-arachidonic acid for 30 minutes and then incubated for 10 minutes with platelet activating factor (PAF) and aspirin. Cyclo-oxygenase (thromboxane, PGE2, PGF2 alpha, and HHT) and lipoxygenase (12-HETE) arachidonic acid metabolites were measured by high pressure liquid chromatography. Release of oxygen free radicals after incubation with PAF and aspirin was measured by chemiluminescence. Platelet levels of glutathione peroxidase (GSH-Px) were also measured using spectrophotometry. RESULTS--Platelets from aspirin-intolerant asthmatic patients produced higher quantities of arachidonic acid metabolites than the control group at baseline conditions. This increase was significant only for lipoxygenase products. No differences were found amongst the three groups in the response of arachidonic acid metabolism to PAF and aspirin. Incubation with aspirin but not with PAF caused an increase in oxygen-free radical production in aspirin-intolerant patients whereas in aspirin-tolerant patients PAF, rather than aspirin, was the more potent stimulus for oxygen-free radical production. No differences in GSH-Px levels were found amongst the three groups. CONCLUSIONS--These results suggest that the platelet lipoxygenase pathway is activated in aspirin-intolerant patients and that the production of oxygen-free radicals may

  7. Receptor-mediated inhibition of adenylate cyclase and stimulation of arachidonic acid release in 3T3 fibroblasts. Selective susceptibility to islet-activating protein, pertussis toxin

    SciTech Connect

    Murayama, T.; Ui, M.

    1985-06-25

    Thrombin exhibited diverse effects on mouse 3T3 fibroblasts. It (a) decreased cAMP in the cell suspension, (b) inhibited adenylate cyclase in the Lubrol-permeabilized cell suspension in a GTP-dependent manner, increased releases of (c) arachidonic acid and (d) inositol from the cell monolayer prelabeled with these labeled compounds, (e) increased /sup 45/Ca/sup 2 +/ uptake into the cell monolayer, and (f) increased /sup 86/Rb/sup +/ uptake into the cell monolayer in a ouabain-sensitive manner. Most of the effects were reproduced by bradykinin, platelet-activating factor, and angiotensin II. The receptors for these agonists are thus likely to be linked to three separate effector systems: the adenylate cyclase inhibition, the phosphoinositide breakdown leading to Ca/sup 2 +/ mobilization and phospholipase A2 activation, and the Na,K-ATPase activation. Among the effects of these agonists, (a), (b), (c), and (e) were abolished, but (d) and (f) were not, by prior treatment of the cells with islet-activating protein (IAP), pertussis toxin, which ADP-ribosylates the Mr = 41,000 protein, the alpha-subunit of the inhibitory guanine nucleotide regulatory protein (Ni), thereby abolishing receptor-mediated inhibition of adenylate cyclase. The effects (a), (c), (d), and (e) of thrombin, but not (b), were mimicked by A23187, a calcium ionophore. The effects of A23187, in contrast to those of receptor agonists, were not affected by the treatment of cells with IAP. Thus, the IAP substrate, the alpha-subunit of Ni, or the protein alike, may play an additional role in signal transduction arising from the Ca/sup 2 +/-mobilizing receptors, probably mediating process(es) distal to phosphoinositide breakdown and proximal to Ca/sup 2 +/ gating.

  8. Ca/sup 2 +/-dependent and Ca/sup 2 +/-independent pathways for release of arachidonic acid from phosphatidylinositol in endothelial cells

    SciTech Connect

    Martin, T.W.; Wysolmerski, R.B.

    1987-09-25

    The pathways for degradation of phosphatidylinositol (PI) were investigated in sonicated suspensions prepared from confluent cultures of bovine pulmonary artery endothelial cells. The time courses of formation of /sup 3/H-labeled and /sup 14/C-labeled metabolites of phosphatidyl-(/sup 3/H)inositol ((/sup 3/H)Ins-PI) and 1-stearoyl-2-(/sup 14/C) arachidonoyl-PI were determined at 37/sup 0/C and pH 7.5 in the presence of 2 mM EDTA with or without a 2 mM excess of Ca/sup 2 +/. The rates of formation of lysophosphatidyl-(/sup 3/H)inositol ((/sup 3/H)Ins-lyso-PI) and 1-lyso-2-(/sup 14/C) arachidonoyl-PI were similar in the presence and absence of Ca/sup 2 +/, and the absolute amounts of the two radiolabeled lyso-PI products formed were nearly identical. This indicated that lyso-PI was formed by phospholipase A1, and phospholipase A2 was not measurable. In the presence of EDTA, (/sup 14/C)arachidonic acid release from 1-stearoyl-2-(/sup 14/C)arachidonoyl-PI paralleled release of glycerophospho-(/sup 3/H)inositol ((/sup 3/H)GPI) from (/sup 3/H)Ins-PI. Formation of (/sup 3/H)GPI was inhibited by treatment with the specific sulfhydryl reagent, 2,2'-dithiodipyridine, and this was accompanied by an increase in (/sup 3/H)Ins-lyso-PI. In the presence of Ca/sup 2 +/, (/sup 14/C) arachidonic acid release from 1-stearoyl-2-(/sup 14/C)arachidonoyl-PI was increased 2-fold and was associated with Ca/sup 2 +/-dependent phospholipase C activity. Under these conditions, (/sup 3/H)inositol monophosphate production exceeded formation of (/sup 14/C)arachidonic acid-labeled phospholipase C products, diacylglycerol plus monoacylglycerol, by an amount that was equal to the amount of (/sup 14/C)arachidonic acid formed in excess of (/sup 3/H)GPI. Low concentrations of phenylmethanesulfonyl fluoride (15-125 microM) inhibited Ca/sup 2 +/-dependent (/sup 14/C)arachidonic acid release, and the decrease in (/sup 14/C) arachidonic acid formed was matched by an equivalent increase in /sup 14/C label

  9. Arachidonic acid supplementation does not affect N-methyl-N-nitrosourea-induced renal preneoplastic lesions in young Lewis rats.

    PubMed

    Yoshizawa, Katsuhiko; Emoto, Yuko; Kinoshita, Yuichi; Kimura, Ayako; Uehara, Norihisa; Yuri, Takashi; Shikata, Nobuaki; Hamazaki, Tomohito; Tsubura, Airo

    2013-04-01

    Arachidonic acid (AA) is naturally found in human breast milk. AA, together with docosahexaenoic acid, is commonly added as a functional food ingredient to commercial infant formula worldwide, in accordance with the international standards of Codex Alimentarius. However, few studies of the possible renal carcinogenic effects of AA supplementation during neonatal life have been performed. The effect of dietary AA supplementation in dams during gestation and lactation was investigated on N-methyl-N-nitrosourea (MNU)-induced preneoplastic lesions in the kidneys of young Lewis rats. Dams were fed a 2.0% AA diet or a basal diet (<0.01% AA). At birth (postnatal day 0), male and female pups received a single intraperitoneal injection of 35 mg/kg MNU or vehicle. Renal morphology was examined after 7, 14, 21, 28 and 60 days. Histopathologically, renal preneoplastic lesions, such as nephroblastomatosis and mesenchymal cell proliferation, were found on day 60 in both the MNU-treated groups. There was no significant difference in lesion incidence of 38% in the basal diet group and 31% in the AA diet group. In conclusion, an AA-rich diet for dams during gestation and lactation does not modify MNU-induced renal preneoplastic lesions in their offspring.

  10. Altered 1-/sup 14/C arachidonic acid metabolism in arterial wall from patients with renal cell carcinoma

    SciTech Connect

    Neri Serneri, G.G.; Abbate, R.; Gensini, G.F.; Panetta, A.; Casolo, G.C.; Costantini, A.; Carini, M.; Selli, C.

    1986-05-01

    The metabolism of 1-/sup 14/C arachidonic acid (AA) by arterial wall in patients with renal cell carcinoma and in control patients undergoing nephrectomy was investigated by a high pressure liquid chromatography (HPLC) system. No differences in 1-/sup 14/C AA uptake and in the total amount of metabolites were found between the two groups, whereas the amounts of cyclooxygenase and lipoxygenase pathway (COP and LOP) metabolites produced by patients with renal cell carcinoma were significantly lower and, respectively, higher than those produced by the control group. The COP/LOP ratio was 7.2 +/- 5.5 in the control group in comparison to 1.9 +/- 0.5 in renal cell carcinoma patients. The decrease in COP metabolites was due to a markedly reduced synthesis of prostacyclin (PGI2), with no changes in thromboxane B2 (TxB2), prostaglandin F2 alpha (PGF2 alpha) and prostaglandin E2 (PGE2) production. The changes in PGI2 and 12-hydroxy-eicosatetraenoic acid (12-HETE) (metabolite of LOP) vascular production were not related to tumor dimension. The decrease in PGI2 synthesis may represent a factor favoring metastasis and thrombosis in neoplastic patients.

  11. The effects of centrally injected arachidonic acid on respiratory system: Involvement of cyclooxygenase to thromboxane signaling pathway.

    PubMed

    Erkan, Leman Gizem; Guvenc, Gokcen; Altinbas, Burcin; Niaz, Nasir; Yalcin, Murat

    2016-05-01

    Arachidonic acid (AA) is a polyunsaturated fatty acid that is present in the phospholipids of the cell membranes of the body and is abundant in the brain. Exogenously administered AA has been shown to affect brain metabolism and to exhibit cardiovascular and neuroendocrine actions. However, little is known regarding its respiratory actions and/or central mechanism of its respiratory effects. Therefore, the present study was designed to investigate the possible effects of centrally injected AA on respiratory system and the mediation of the central cyclooxygenase (COX) to thromboxane A2 (TXA2) signaling pathway on AA-induced respiratory effects in anaesthetized rats. Intracerebroventricular (i.c.v.) administration of AA induced dose- and time-dependent increase in tidal volume, respiratory rates and respiratory minute ventilation and also caused an increase in partial oxygen pressure (pO2) and decrease in partial carbon dioxide pressure (pCO2) in male anaesthetized Spraque Dawley rats. I.c.v. pretreatment with ibuprofen, a non-selective COX inhibitor, completely blocked the hyperventilation and blood gases changes induced by AA. In addition, central pretreatment with different doses of furegrelate, a TXA2 synthesis inhibitor, also partially prevented AA-evoked hyperventilation and blood gases effects. These data explicitly show that centrally administered AA induces hyperventilation with increasing pO2 and decreasing pCO2 levels which are mediated by the activation of central COX to TXA2 signaling pathway.

  12. Aureispira marina gen. nov., sp. nov., a gliding, arachidonic acid-containing bacterium isolated from the southern coastline of Thailand.

    PubMed

    Hosoya, Shoichi; Arunpairojana, Vullapa; Suwannachart, Chatrudee; Kanjana-Opas, Akkharawit; Yokota, Akira

    2006-12-01

    Three strains of gliding bacteria, 24(T), 62 and 71, isolated from a marine sponge and algae from the southern coastline of Thailand, were studied using a polyphasic approach to clarify their taxonomic positions. A phylogenetic analysis based on 16S rRNA gene sequences showed that the three isolates formed a distinct lineage within the family 'Saprospiraceae' of the phylum Bacteroidetes and were related to members of the genus Saprospira. The G+C contents of the isolates were in the range 38-39 mol%. The major respiratory quinone was MK-7. The predominant cellular fatty acids were 20 : 4omega6c (arachidonic acid), 16 : 0 and iso-17 : 0. On the basis of morphological, physiological and chemotaxonomic characteristics, together with DNA-DNA hybridization data and 16S rRNA gene sequences, the isolates represent a novel species of a novel genus, for which the name Aureispira marina gen. nov., sp. nov. is proposed. The type strain of Aureispira marina is 24(T) (=IAM 15389(T)=TISTR 1719(T)).

  13. Arachidonic acid has protective effects on oxygen-glucose deprived astrocytes mediated through enhancement of potassium channel TREK-1 activity.

    PubMed

    Lu, Li; Zhang, Guangru; Song, Chunli; Wang, Xuexi; Qian, Weina; Wang, Zhuanling; Liu, Yanan; Gong, Sheng; Zhou, Shuning

    2017-01-01

    Polyunsaturated fatty acids (PUFAs) have neuroprotective effects against ischemic brain diseases. The newly discovered potassium channel "TREK-1" is a promising target for therapies against neurodegeneration. Arachidonic acid (AA) is an n-6 PUFA, as well as a potent TREK-1 activator. We previously showed that TREK-1 is expressed at high levels in astrocytes. However, the effect of AA on astrocytes in ischemia remains unknown. Here, we assessed the effects of 3-30μM AA on astrocyte apoptosis, glutamate uptake, and expression of the astrocytic glutamate transporter 1 (GLT-1) and TREK-1 under different conditions. Under normal conditions, 3-30μM AA showed no effect on astrocytic apoptosis or TREK-1 expression, whereas glutamate uptake decreased significantly and its change paralleled the decreased expression of GLT-1. When astrocytes were subjected to 4h of oxygen-glucose deprivation (OGD), 10μM AA markedly alleviated OGD-induced cell death, recovering from 63.50±1.90% to 82.96±4.63% of the control value. AA also rescued the decreased glutamate uptake and increased mRNA, as well as protein levels of GLT-1 and TREK-1. Our results provide new evidence of a protective effect of AA on astrocytes under OGD conditions, suggesting that a low concentration of AA may protect against brain ischemic diseases.

  14. Influence of formulas with borage oil or borage oil plus fish oil on the arachidonic acid status in premature infants.

    PubMed

    Demmelmair, H; Feldl, F; Horváth, I; Niederland, T; Ruszinkó, V; Raederstorff, D; De Min, C; Muggli, R; Koletzko, B

    2001-06-01

    Several studies have reported that feeding gamma-linolenic acid (GLA) has resulted in no increase in arachidonic acid (AA) in newborns. This result was ascribed to the eicosapentaenoic acid (EPA)-rich fish oil used in these formulas. Docosahexaenoic acid (DHA) sources with only minor amounts of EPA are now available, thus the addition of GLA to infant formulas might be considered an alternative to AA supplementation. Sixty-six premature infants were randomized to feeding one of four formulas [ST: no GLA, no long-chain polyunsaturated fatty acids; BO: 0.6% GLA (borage oil); BO + FOLOW: 0.6% GLA, 0.3% DHA, 0.06% EPA; BO + FOHIGH: 0.6% GLA, 0.3% DHA, 0.2% EPA] or human milk (HM, nonrandomized) for 4 wk. Anthropometric measures and blood samples were obtained at study entry and after 14 and 28 d. There were no significant differences between groups in anthropometric measures, tocopherol, and retinol status at any of the studied time points. The AA content of plasma phospholipids was similar between groups at study start and decreased significantly until day 28 in all formulafed groups, but not in the breast-fed infants [ST: 6.6 +/- 0.2%, BO: 6.9 +/- 0.3%, BO + FOLOW: 6.9 +/- 0.4%, BO + FOHIGH: 6.7 +/- 0.2%, HM: 8.6 +/- 0.5%, where values are reported as mean +/- standard error; all formulas significantly different (P< 0.05) from HM]. There was no significant influence of GLA or fish oil addition to the diet. GLA had only a very limited effect on AA status which was too small to obtain satisfactory concentrations (concentrations similar to breast-fed babies) under the circumstances tested. The effect of GLA on AA is independent of the EPA and DHA content in the diet within the dose ranges studied.

  15. COX-2, aspirin and metabolism of arachidonic, eicosapentaenoic and docosahexaenoic acids and their physiological and clinical significance.

    PubMed

    Poorani, R; Bhatt, Anant N; Dwarakanath, B S; Das, Undurti N

    2016-08-15

    Polyunsaturated fatty acids (PUFAs) are vital for normal growth and development and physiological function of various tissues in humans. PUFAs have immunomodulatory actions in addition to their ability to modulate inflammation, vascular reactivity, neurotransmission and stem cell biology. PUFAs and their metabolites possess both pro- and anti-inflammatory properties that underlie their actions and involvement in several diseases. Aspirin, a non-steroidal anti-inflammatory drug (NSAID), possesses both cyclo-oxygenase (COX) and lipoxygenase (LOX) inhibitory action and enhances the production of anti-inflammatory lipoxin A4 {(called as epi-lipoxin A4, aspirin-triggered lipoxins (ATLs))}. In addition, at low doses aspirin may not interfere with the production of prostacyclin (PGI2). Both lipoxin A4 and PGI2 have vasodilator, platelet anti-aggregator and anti-inflammatory actions that may underlie the beneficial actions of aspirin. Paradoxically, other NSAIDs may not have the same actions as that of aspirin on PUFA metabolism. Similar anti-inflammatory compounds are formed from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by the action of aspirin termed as resolvins (from EPA and DHA) and protectins and maresins from DHA. PUFAs: arachidonic acid (AA), EPA and DHA and their various products modulate not only inflammation and immune response but also possess actions on various genes, nuclear factors, cyclic AMP and GMP, G-protein coupled receptors (GPRs), hypothalamic neurotransmitters, hormones, cytokines and enzymes, and interact with nitric oxide, carbon monoxide, and hydrogen sulfide to regulate their formation and action and to form new compounds that have several biological actions. These pleiotropic actions of PUFAs and their metabolites may explain their ability to play a role in several physiological actions and diseases. The big challenge is to harness these actions to prevent and manage clinical conditions.

  16. Upregulated expression of brain enzymatic markers of arachidonic and docosahexaenoic acid metabolism in a rat model of the metabolic syndrome

    PubMed Central

    2012-01-01

    Background In animal models, the metabolic syndrome elicits a cerebral response characterized by altered phospholipid and unesterified fatty acid concentrations and increases in pro-apoptotic inflammatory mediators that may cause synaptic loss and cognitive impairment. We hypothesized that these changes are associated with phospholipase (PLA2) enzymes that regulate arachidonic (AA, 20:4n-6) and docosahexaenoic (DHA, 22:6n-6) acid metabolism, major polyunsaturated fatty acids in brain. Male Wistar rats were fed a control or high-sucrose diet for 8 weeks. Brains were assayed for markers of AA metabolism (calcium-dependent cytosolic cPLA2 IVA and cyclooxygenases), DHA metabolism (calcium-independent iPLA2 VIA and lipoxygenases), brain-derived neurotrophic factor (BDNF), and synaptic integrity (drebrin and synaptophysin). Lipid concentrations were measured in brains subjected to high-energy microwave fixation. Results The high-sucrose compared with control diet induced insulin resistance, and increased phosphorylated-cPLA2 protein, cPLA2 and iPLA2 activity and 12-lipoxygenase mRNA, but decreased BDNF mRNA and protein, and drebrin mRNA. The concentration of several n-6 fatty acids in ethanolamine glycerophospholipids and lysophosphatidylcholine was increased, as was unesterified AA concentration. Eicosanoid concentrations (prostaglandin E2, thromboxane B2 and leukotriene B4) did not change. Conclusion These findings show upregulated brain AA and DHA metabolism and reduced BDNF and drebrin, but no changes in eicosanoids, in an animal model of the metabolic syndrome. These changes might contribute to altered synaptic plasticity and cognitive impairment in rats and humans with the metabolic syndrome. PMID:23110484

  17. 12(R)-hydroxyicosatetraenoic acid: a cytochrome P450-dependent arachidonate metabolite that inhibits Na/sup +/, K/sup +/-ATPase in the cornea

    SciTech Connect

    Schwartzman, M.L.; Balazy, M.; Masferrer, J.; Abraham, N.G.; McGiff, J.C.; Murphy, R.C.

    1987-11-01

    When corneal microsomes were incubated with arachidonic acid in the presence of an NADPH-generating system, four polar metabolites (compounds A-D) were formed. Synthesis of these metabolites could be inhibited by carbon monoxide, SKF 525A, and anti-cytochrome c reductase antibodies. One of the metabolites, compound C, was found to inhibit partially purified Na/sup +/, K/sup +/-ATPase from the corneal epithelium in a dose-dependent manner. After compound C was purified by TLC and HPLC, it was found to have a UV absorption spectrum with a maximum absorbance at 236 nm suggesting the presence of a conjugated diene. Mass spectrometric analysis using positive- and negative-ionization modes was carried out on derivatized compound C. Abundant fragment ions were consistent with compound C being a monooxygenated derivative of arachidonic acid with a hydroxyl substituent at carbon-12 of the icosanoid backbone; all deuterium atoms from (/sup 2/H/sub 8/)arachidonate were retained in the structure. Compound C was characterized as a 12-hydroxyicosatetraenoic acid. However, only 12(R) isomer was found to be an inhibitor of the Na/sup +/, K/sup +/-ATPase from the corneal epithelium, suggesting that the biologically active compound C was 12(R)-hydroxyy-5,8,10,14-icosatetraenoic acid. Such an inhibitor of Na/sup +/, K/sup +/-ATPase synthesized in the cornea may have an important role in regulating ocular transparency and aqueous human secretion.

  18. Involvement of de Novo Protein Synthesis, Protein Kinase, Extracellular Ca2+, and Lipoxygenase in Arachidonic Acid Induction of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Genes and Isoprenoid Accumulation in Potato (Solanum tuberosum L.).

    PubMed Central

    Choi, D.; Bostock, R. M.

    1994-01-01

    A series of inhibitors were tested to determine the participation of de novo protein synthesis, protein kinase activity, extracellular Ca2+, and lipoxygenase activity in arachidonic acid elicitation of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene expression and sesquiterpene phytoalexin biosynthesis in potato (Solanum tuberosum L. cv Kennebec). Gene-specific probes were used to discriminate effects on the expression of two HMGR genes (hmg1 and hmg2) that respond differentially in tuber tissue following wounding or elicitor treatment. Inhibition of protein synthesis with cycloheximide completely blocked arachidonate-induced hypersensitive necrosis and browning, including HMGR gene induction and phytoalexin accumulation. This suggests that proteins necessary for coupling arachidonic acid reception to HMGR mRNA accumulation are either rapidly turned over or not present constitutively and are induced following elicitor treatment. Staurosporin, a potent inhibitor of protein kinases, and ethyleneglycol-bis([beta]-aminoethyl ether)-N,N[prime]-tetraacetic acid, a Ca2+ chelator, inhibited arachidonate-induction of hmg2 gene expression and phytoalexin accumulation but did not inhibit the wound-induced expression of hmg1. However, staurosporin inhibited arachidonate's suppression of hmg1 gene expression. Eicosatetraynoic acid, a lipoxygenase inhibitor that suppresses elicitor-induced phytoalexin accumulation, also inhibited arachidonate's suppression of hmg1 and induction of hmg2. The results indicate that arachidonate's suppression of hmg1 and activation of hmg2 depend on a common intermediate or set of intermediates whose generation is sensitive to the inhibitors tested. PMID:12232162

  19. [Effect of dauricine on rat and human platelet aggregation and metabolism of arachidonic acid in washed rat platelets].

    PubMed

    Tong, L; Yue, T L

    1989-01-01

    Dauricine (Dau), an isoquinoline alkaloid extracted from the roots of Menispermum dauricum D. C. and used as an antiarrhythmic agent in China recently, was shown to inhibit rat platelet aggregation induced by arachidonic acid (AA) and ADP, as well as human platelet aggregation induced by AA, ADP and adrenaline (Adr) in vitro in a dose-dependent manner. The concentration of Dau required for 50% inhibition (IC50) of rat platelet aggregation induced by AA and ADP was 26 and 37 mumol/L, respectively. For human platelet aggregation induced by AA, ADP and Adr the IC50 of Dau was found to be 39, 55 and 43 mumol/L, respectively. Dau inhibited the cyclooxygenase pathway metabolites of AA (TXB2 and HHT) in washed intact rat platelets. The production of TXB2 and HHT was reduced by 26% and 19%, respectively, when the Dau concentration was 50 mumol/L and by 46 and 45%, respectively, when the concentration of Dau was 100 mumol/L. The formation of 12-HETE was also inhibited at 100 mumol/L of Dau. The inhibitory effect of Dau on AA metabolism may be one of the mechanisms related to its inhibition of platelet aggregation.

  20. Effects of arachidonic acid intake on inflammatory reactions in dextran sodium sulphate-induced colitis in rats.

    PubMed

    Naito, Yukiko; Ji, Xu; Tachibana, Shigehiro; Aoki, Satoko; Furuya, Mami; Tazura, Yoshiyuki; Miyazawa, Daisuke; Harauma, Akiko; Moriguchi, Toru; Nagata, Tomoko; Iwai, Naoharu; Ohara, Naoki

    2015-09-14

    The aim of this study was to investigate the effects of the administration of oral arachidonic acid (AA) in rats with or without dextran sulphate sodium (DSS)-induced inflammatory bowel disease. Male Wistar rats were administered AA at 0, 5, 35 or 240 mg/kg daily by gavage for 8 weeks. Inflammatory bowel disease was induced by replacing drinking water with 3 % DSS solution during the last 7 d of the AA dosing period. These animals passed loose stools, diarrhoea and red-stained faeces. Cyclo-oxygenase-2 concentration and myeloperoxidase activity in the colonic tissue were significantly increased in the animals given AA at 240 mg/kg compared with the animals given AA at 0 mg/kg. Thromboxane B2 concentration in the medium of cultured colonic mucosae isolated from these groups was found to be dose-dependently increased by AA, and the increase was significant at 35 and 240 mg/kg. Leukotriene B4 concentration was also significantly increased and saturated at 5 mg/kg. In addition, AA at 240 mg/kg promoted DSS-induced colonic mucosal oedema with macrophage infiltration. In contrast, administration of AA for 8 weeks, even at 240 mg/kg, showed no effects on the normal rats. These results suggest that in rats with bowel disease AA metabolism is affected by oral AA, even at 5 mg/kg per d, and that excessive AA may aggravate inflammation, whereas AA shows no effects in rats without inflammatory bowel disease.

  1. Lipid droplets in activated mast cells - a significant source of triglyceride-derived arachidonic acid for eicosanoid production.

    PubMed

    Dichlberger, Andrea; Schlager, Stefanie; Kovanen, Petri T; Schneider, Wolfgang J

    2016-08-15

    Mast cells are potent effectors of immune reactions and key players in various inflammatory diseases such as atherosclerosis, asthma, and rheumatoid arthritis. The cellular defense response of mast cells represents a unique and powerful system, where external signals can trigger cell activation resulting in a stimulus-specific and highly coordinated release of a plethora of bioactive mediators. The arsenal of mediators encompasses preformed molecules stored in cytoplasmic secretory granules, as well as newly synthesized proteinaceous and lipid mediators. The release of mediators occurs in strict chronological order and requires proper coordination between the endomembrane system and various enzymatic machineries. For the generation of lipid mediators, cytoplasmic lipid droplets have been shown to function as a major intracellular pool of arachidonic acid, the precursor for eicosanoid biosynthesis. Recent studies have revealed that not only phospholipids in mast cell membranes, but also triglycerides in mast cell lipid droplets are a substrate source for eicosanoid formation. The present review summarizes current knowledge about mast cell lipid droplet biology, and discusses expansions and challenges of traditional mechanistic models for eicosanoid production.

  2. Efficient arachidonic acid-rich oil production by Mortierella alpina through a repeated fed-batch fermentation strategy.

    PubMed

    Ji, Xiao-Jun; Zhang, Ai-Hui; Nie, Zhi-Kui; Wu, Wen-Jia; Ren, Lu-Jing; Huang, He

    2014-10-01

    Arachidonic acid (ARA)-rich oil production by Mortierella alpina is a long fermentation period needed process due to the low growth rate of the filamentous fungus used. This causes the low productivity of ARA-rich oil and hinders its industrial mass scale production. In the present study, different fed-batch strategies were conducted to shorten the fermentation period. The result showed that compared with the batch culture, the fermentation period was shortened from 7days to 5days with the productivity of ARA-rich oil increased from 0.9g/(L·d) to 1.3g/(L·d) by using the fed-batch fermentation strategy. Furthermore, repeated fed-batch fermentation strategy was adopted to achieve the purpose of continuous production. By using this strategy, the fermentation period was shortened from 40days to 26days in a four cycle repeated fed-batch fermentation. This strategy proved to be convenient and economical for ARA-rich oil commercial production process.

  3. Gabapentin's minimal action on markers of rat brain arachidonic acid metabolism agrees with its inefficacy against bipolar disorder.

    PubMed

    Reese, Edmund A; Cheon, Yewon; Ramadan, Epolia; Kim, Hyung-Wook; Chang, Lisa; Rao, Jagadeesh S; Rapoport, Stanley I; Taha, Ameer Y

    2012-01-01

    In rats, FDA-approved mood stabilizers used for treating bipolar disorder (BD) selectively downregulate brain markers of the arachidonic acid (AA) cascade, which are upregulated in postmortem BD brain. Phase III clinical trials show that the anticonvulsant gabapentin (GBP) is ineffective in treating BD. We hypothesized that GBP would not alter the rat brain AA cascade. Chronic GBP (10 mg/kg body weight, injected i.p. for 30 days) compared to saline vehicle did not significantly alter brain expression or activity of AA-selective cytosolic phospholipase A(2) (cPLA(2)) IVA or secretory (s)PLA(2) IIA, activity of cyclooxygenase-2, or prostaglandin E(2) or thromboxane B(2) concentrations. Plasma esterified and unesterified AA concentration was unaffected. These results, taken with evidence of an upregulated AA cascade in the BD brain and that approved mood stabilizers downregulate the rat brain AA cascade, support the hypothesis that effective anti-BD drugs act by targeting the brain AA cascade whereas ineffective drugs (such as GBP) do not target this pathway, and suggest that the rat model might be used for screening new anti-BD drugs.

  4. Nitro-Arachidonic Acid Prevents Angiotensin II-Induced Mitochondrial Dysfunction in a Cell Line of Kidney Proximal Tubular Cells.

    PubMed

    Sánchez-Calvo, Beatriz; Cassina, Adriana; Rios, Natalia; Peluffo, Gonzalo; Boggia, José; Radi, Rafael; Rubbo, Homero; Trostchansky, Andres

    2016-01-01

    Nitro-arachidonic acid (NO2-AA) is a cell signaling nitroalkene that exerts anti-inflammatory activities during macrophage activation. While angiotensin II (ANG II) produces an increase in reactive oxygen species (ROS) production and mitochondrial dysfunction in renal tubular cells, little is known regarding the potential protective effects of NO2-AA in ANG II-mediated kidney injury. As such, this study examines the impact of NO2-AA on ANG II-induced mitochondrial dysfunction in an immortalized renal proximal tubule cell line (HK-2 cells). Treatment of HK-2 cells with ANG II increases the production of superoxide (O2●-), nitric oxide (●NO), inducible nitric oxide synthase (NOS2) expression, peroxynitrite (ONOO-) and mitochondrial dysfunction. Using high-resolution respirometry, it was observed that the presence of NO2-AA prevented ANG II-mediated mitochondrial dysfunction. Attempting to address mechanism, we treated isolated rat kidney mitochondria with ONOO-, a key mediator of ANG II-induced mitochondrial damage, in the presence or absence of NO2-AA. Whereas the activity of succinate dehydrogenase (SDH) and ATP synthase (ATPase) were diminished upon exposure to ONOO-, they were restored by pre-incubating the mitochondria with NO2-AA. Moreover, NO2-AA prevents oxidation and nitration of mitochondrial proteins. Combined, these data demonstrate that ANG II-mediated oxidative damage and mitochondrial dysfunction is abrogated by NO2-AA, identifying this compound as a promising pharmacological tool to prevent ANG II-induced renal disease.

  5. The effect of antibiotic exposure on eicosanoid generation from arachidonic acid and gene expression in a primitive chordate, Branchiostoma belcheri

    PubMed Central

    Yuan, Dongjuan; Pan, Minming; Zou, Qiuqiong; Chen, Chengyong; Chen, Shangwu; Xu, Anlong

    2015-01-01

    Chloramphenicol (Chl) is an effective antimicrobial agent widely used in veterinary medicine and commonly used in fish. Its use is restricted in the clinic because of adverse effects on the immune system and oxidative stress in mammals. However, the effects of Chl treatment on invertebrates remain unclear. Amphioxus, a basal chordate, is an ideal model to study the origin and evolution of the vertebrate immune system as it has a primary vertebrate-like arachidonic acid (AA) metabolic system. Here, we combined transcriptomic and lipidomic approaches to investigate the immune system and observe the oxygenated metabolites of AA to address the antibiotic effects on amphioxus. Tissue necrosis of the gill slits occurred in the Chl-treated amphioxus, but fewer epithelial cells were lost when treated with both Chl and ampicillin (Amp). The immune related pathways were dysregulated in both of the antibiotic treatment groups. The Chl alone treatment resulted in immunosuppression with down-regulation of the innate immune genes. In contrast, the Chl + Amp treatment resulted in immunostimulation to some extent, as shown by KEGG clustering. Furthermore, Chl induced a 3-fold reduction in the level of the eicosanoids, while the Chl + Amp treatment resulted in 1.7-fold increase of eicosanoid level. Thus in amphioxus, Amp might relieve the effects of the Chl-induced immune suppression and increase the level of eicosanoids from AA. Finally, the oxygenated metabolites from AA might be crucial to evaluate the effects of Chl treatment in animals. PMID:26288743

  6. SIRT1 prevents pulmonary thrombus formation induced by arachidonic acid via downregulation of PAF receptor expression in platelets.

    PubMed

    Kim, Yun Hak; Bae, Jin Ung; Kim, In Suk; Chang, Chulhun L; Oh, Sae Ock; Kim, Chi Dae

    2016-12-01

    SIRT1, a class III histone deacetylase, is critically involved in cellular response to stress and modulates cardiovascular risk factors. However, its role in thrombus formation is largely unknown. Thus, this study investigated the effect of SIRT1 on pulmonary thrombus formation, and then identified its role in the modulation of platelet aggregation. In isolated human platelets, cell aggregation was increased by various platelet activators, such as platelet activating factor (PAF), arachidonic acid (AA), ADP, and thrombin. AA- and PAF-mediated platelet aggregations were suppressed by WEB2086, a PAF receptor (PAFR) antagonist. Pulmonary thrombus formation induced by PAF or AA was also attenuated by WEB2086, suggesting that PAFR plays a key role in AA-induced platelet aggregation. In platelets isolated from SIRT1-TG mice as well as in platelets treated with resveratrol or reSIRT1, PAFR expression was decreased, whereas this expressional downregulation by SIRT1 activators was inhibited in platelets treated with MG132 (a proteasome inhibitor) or NH4Cl (a lysosome inhibitor). Furthermore, platelet aggregation induced by AA was markedly attenuated by resveratrol and reSIRT1. Likewise, the increased pulmonary thrombus formation in mice treated with AA was also attenuated by SIRT1 activators. In line with these results, pulmonary thrombus formation was markedly attenuated in SIRT1-TG mice. Taken together, this study showed that SIRT1 downregulates PAFR expression on platelets via proteasomal and lysosomal pathways, and that this downregulation inhibits platelet aggregation in vitro and pulmonary thrombus formation in vivo.

  7. [The vascular effects of thrombin on canine and human arteries; their independence from the metabolism of arachidonic acid].

    PubMed

    Escalante Acosta, B A; Amezcua Gastelum, J L; Aldana Alcalá, I

    1994-01-01

    Independently of it's effects on the coagulation cascade, thrombin can interact with the endothelium and release vasodilatory mediators as prostacyclin, endothelium dependent relaxing factor and potentiate the vascular changes induced by vasoconstrictors like endothelin or cathecolamines. Therefore, in the present study we tested the effect of thrombin in the pulmonary and femoral canine arteries and compared it with the effects on human umbilical artery; we also explore the possible mechanism of action of thrombin-induced changes in vascular tone by using specific inhibitors. Thrombin induced a concentration-dependent and endothelium-dependent relaxation on canine arteries (pulmonary or femoral) and endothelium-independent contraction of human umbilical arteries, neither the relaxation nor the contraction were significantly affected by incubation of the vessels with: a cyclooxygenase inhibitor (indomethacin), lypooxygenase inhibitor (BW 755C) or a soup of antagonists (atropine, metysergyde, propanolol, meperamine or phenoribenzamine) to block muscarinic, histaminic, serotoninergic or adrenergic receptors. However, incubation of the vessels with heparin or a calcium channel blocker did prevented the vasoconstrictor effect of thrombin in human umbilical veins. This results suggests that thrombin can elicit changes in vascular tone and the effect is dependent of the vessel stimulated, and the presence of the endothelium. Thus, thrombin-dependent change in vascular tone is not mediated by arachidonic acid metabolites, sympathetic or parasympathetic neurotransmitters, histamine or serotonine receptors. Thrombin effects may be mediated by interaction with an specific receptor coupled with a calcium signal.

  8. Maternal arachidonic acid supplementation improves neurodevelopment in young adult offspring from rat dams with and without diabetes.

    PubMed

    Zhao, Jinping; Del Bigio, Marc R; Weiler, Hope A

    2011-01-01

    Maternal diabetes may compromise infant arachidonic acid (AA) status and development. This study tested if maternal AA supplementation improves neurodevelopment in adult offspring. Rat dams were randomized into 6 groups: Saline-Placebo, streptozotocin-induced diabetes with glucose controlled at <13mmol/L, or poorly controlled at 13-20mmol/L using insulin; and fed either a Control or AA (0.5% fat) diet throughout reproduction. Weaned-offspring were fed regular chow to 12 weeks of age. Testing included exploratory behavior, rota rod and water maze (WM). Poorly controlled offspring showed longer (p≤0.018) escape-latency on testing-day 1 WM but not thereafter (p>0.05). Maternal glucose concentration positively correlated with (p=0.006) male offspring testing-day 1 WM latency. The AA-diet offspring performed better in WM and rota rod (p≤0.032) and showed higher exploratory behavior (p=0.008) than Control-diet offspring. These data suggest maternal hyperglycemia has longstanding consequences to initial stages of learning in the offspring. Maternal AA supplementation and training positively influence learning outcomes.

  9. Knocking out the dopamine reuptake transporter (DAT) does not change the baseline brain arachidonic acid signal in the mouse

    PubMed Central

    Ramadan, Epolia; Chang, Lisa; Chen, Mei; Ma, Kaizong; Hall, F. Scott; Uhl, George R.; Rapoport, Stanley I.; Basselin, Mireille

    2012-01-01

    Background Dopamine transporter (DAT) homozygous knockout (DAT−/−) mice have a 10-fold higher extracellular DA concentration in the caudate-putamen and nucleus accumbens than do wildtype (DAT+/+) mice, but show reduced presynaptic DA synthesis and fewer postsynaptic D2 receptors. One aspect of neurotransmission involves DA binding to postsynaptic D2-like receptors coupled to cytosolic phospholipase A2 (cPLA2), releasing second messenger arachidonic acid (AA) from synaptic membrane phospholipid. We hypothesized that tonic overactivation of D2-like receptors in DAT−/− mice due to elevated DA would not increase brain AA signaling, because of compensatory downregulation of postsynaptic signaling mechanisms. Methods [1-14C]AA was infused intravenously for 3 min in unanesthetized DAT+/+, heterozygous (DAT+/−) and DAT−/− mice. AA incorporation coefficients k* and rates Jin, markers of AA metabolism and signaling, were imaged in 83 brain regions using quantitative autoradiography brain cPLA2-IV activity also was measured. Results Neither k* nor Jin for AA in any brain region, or in brain cPLA2-IV activity, differed significantly between DAT−/−, DAT+/− and DAT+/+ mice. Conclusions These results differ from reported increases in k* and Jin for AA, and brain cPLA2 expression, in serotonin reuptake transporter (5-HTT) knockout mice, and suggest that postsynaptic dopaminergic neurotransmission mechanisms involving AA are downregulated despite elevated DA in DAT−/− mice. PMID:22376027

  10. Chronic Carbamazepine Administration Attenuates Dopamine D2-like Receptor-Initiated Signaling via Arachidonic Acid in Rat Brain

    PubMed Central

    Chang, Lisa; Chen, Mei; Bell, Jane M.; Rapoport, Stanley I.

    2016-01-01

    Observations that dopaminergic antagonists are beneficial in bipolar disorder and that dopaminergic agonists can produce mania suggest that bipolar disorder involves excessive dopaminergic transmission. Thus, mood stabilizers used to treat the disease might act in part by downregulating dopaminergic transmission. In agreement, we reported that dopamine D2-like receptor mediated signaling involving arachidonic acid (AA, 20:4n-6) was downregulated in rats chronically treated with lithium. To see whether chronic carbamazepine, another mood stabilizer, did this as well, we injected i.p. saline or the D2-like receptor agonist, quinpirole (1 mg/kg), into unanesthetized rats that had been pretreated for 30 days with i.p. carbamazepine (25 mg/kg/day) or vehicle, and used quantitative autoradiography to measure regional brain incorporation coefficients (k*) for AA, markers of signaling. We also measured brain prostaglandin E2 (PGE2), an AA metabolite. In vehicle-treated rats, quinpirole compared with saline significantly increased k* for AA in 35 of 82 brain regions examined, as well as brain PGE2 concentration. Affected regions belong to dopaminergic circuits and have high D2-like receptor densities. Chronic carbamazepine pretreatment prevented the quinpirole-induced increments in k* and in PGE2. These findings are consistent with the hypothesis that effective mood stabilizers generally downregulate brain AA signaling via D2-like receptors, and that this signaling is upregulated in bipolar disorder. PMID:18302021

  11. Chronic Valproate Treatment Blocks D2-like Receptor-Mediated Brain Signaling via Arachidonic Acid in Rats

    PubMed Central

    Ramadan, Epolia; Basselin, Mireille; Taha, Ameer Y.; Cheon, Yewon; Chang, Lisa; Chen, Mei; Rapoport, Stanley I.

    2011-01-01

    Background and Objective Hyperdopaminergic signaling and an upregulated brain arachidonic acid (AA) cascade may contribute to bipolar disorder (BD). Lithium and carbamazepine, FDA-approved for the treatment of BD, attenuate brain dopaminergic D2-like (D2, D3, and D4) receptor signaling involving AA when given chronically to awake rats. We hypothesized that valproate (VPA), with mood-stabilizing properties, would also reduce the D2-like-mediated signaling via AA. Methods An acute dose of quinpirole (1 mg/kg) or saline was administered to unanesthetized rats that had been treated for 30 days with a therapeutically relevant dose of VPA (200 mg/kg/day) or vehicle. Regional brain AA incorporation coefficients, k*, and incorporation rates, Jin, markers of AA signaling and metabolism, were measured by quantitative autoradiography after intravenous [1-14C]AA infusion. Whole brain concentrations of prostaglandin (PG)E2 and thromboxane (TX)B2 also were measured. Results Quinpirole compared to saline significantly increased k* in 40 of 83 brain regions, and increased brain concentrations of PGE2 in chronic vehicle-treated rats. VPA treatment by itself reduced concentrations of plasma unesterified AA and whole brain PGE2 and TXB2, and blocked the quinpirole-induced increments in k* and PGE2. Conclusion These results further support our hypothesis that similar to lithium and carbamazepine, VPA downregulates brain dopaminergic D2-like receptor-signaling involving AA. PMID:21839100

  12. Characterization of arachidonic acid metabolism by rat cytochrome P450 enzymes: the involvement of CYP1As.

    PubMed

    El-Sherbeni, Ahmed A; El-Kadi, Ayman O S

    2014-09-01

    Cytochrome P450 (P450) enzymes mediate arachidonic acid (AA) oxidation to several biologically active metabolites. Our aims in this study were to characterize AA metabolism by different recombinant rat P450 enzymes and to identify new targets for modulating P450-AA metabolism in vivo. A liquid chromatography-mass spectrometry method was developed and validated for the simultaneous measurements of AA and 15 of its P450 metabolites. CYP1A1, CYP1A2, CYP2B1, CYP2C6, and CYP2C11 were found to metabolize AA with high catalytic activity, and CYP2A1, CYP2C13, CYP2D1, CYP2E1, and CYP3A1 had lower activity. CYP1A1 and CYP1A2 produced ω-1→4 hydroxyeicosatetraenoic acids (HETEs) as 88.7 and 62.7%, respectively, of the total metabolites formed. CYP2C11 produced epoxyeicosatrienoic acids (EETs) as 61.3%, and CYP2C6 produced midchain HETEs and EETs as 48.3 and 29.4%, respectively, of the total metabolites formed. The formation of CYP1A1, CYP1A2, CYP2C6, and CYP2C11 major metabolites followed an atypical kinetic profile of substrate inhibition. CYP1As inhibition by α-naphthoflavone or anti-CYP1As antibodies significantly reduced ω-1→4 HETE formation in the lungs and liver, whereas CYP1As induction by 3-methylcholanthrene resulted in a significant increase in ω-1→4 HETEs formation in the heart, lungs, kidney, and livers by 370, 646, 532, and 848%, respectively. In conclusion, our results suggest that CYP1As and CYP2Cs are major players in the metabolism of AA. The significant contribution of CYP1As to AA metabolism and their strong inducibility suggest their possible use as targets for the prevention and treatment of several diseases.

  13. Positive Selection on a Regulatory Insertion–Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid

    PubMed Central

    Kothapalli, Kumar S. D.; Ye, , Kaixiong; Gadgil, Maithili S.; Carlson, Susan E.; O’Brien, Kimberly O.; Zhang, Ji Yao; Park, Hui Gyu; Ojukwu, Kinsley; Zou, James; Hyon, Stephanie S.; Joshi, Kalpana S.; Gu, Zhenglong; Keinan, Alon; Brenna, J.Thomas

    2016-01-01

    Long chain polyunsaturated fatty acids (LCPUFA) are bioactive components of membrane phospholipids and serve as substrates for signaling molecules. LCPUFA can be obtained directly from animal foods or synthesized endogenously from 18 carbon precursors via the FADS2 coded enzyme. Vegans rely almost exclusively on endogenous synthesis to generate LCPUFA and we hypothesized that an adaptive genetic polymorphism would confer advantage. The rs66698963 polymorphism, a 22-bp insertion–deletion within FADS2, is associated with basal FADS1 expression, and coordinated induction of FADS1 and FADS2 in vitro. Here, we determined rs66698963 genotype frequencies from 234 individuals of a primarily vegetarian Indian population and 311 individuals from the US. A much higher I/I genotype frequency was found in Indians (68%) than in the US (18%). Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product–precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice. PMID:27188529

  14. Positive Selection on a Regulatory Insertion-Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid.

    PubMed

    Kothapalli, Kumar S D; Ye, Kaixiong; Gadgil, Maithili S; Carlson, Susan E; O'Brien, Kimberly O; Zhang, Ji Yao; Park, Hui Gyu; Ojukwu, Kinsley; Zou, James; Hyon, Stephanie S; Joshi, Kalpana S; Gu, Zhenglong; Keinan, Alon; Brenna, J Thomas

    2016-07-01

    Long chain polyunsaturated fatty acids (LCPUFA) are bioactive components of membrane phospholipids and serve as substrates for signaling molecules. LCPUFA can be obtained directly from animal foods or synthesized endogenously from 18 carbon precursors via the FADS2 coded enzyme. Vegans rely almost exclusively on endogenous synthesis to generate LCPUFA and we hypothesized that an adaptive genetic polymorphism would confer advantage. The rs66698963 polymorphism, a 22-bp insertion-deletion within FADS2, is associated with basal FADS1 expression, and coordinated induction of FADS1 and FADS2 in vitro. Here, we determined rs66698963 genotype frequencies from 234 individuals of a primarily vegetarian Indian population and 311 individuals from the US. A much higher I/I genotype frequency was found in Indians (68%) than in the US (18%). Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product-precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice.

  15. Adenoviral expression of 15-lipoxygenase-1 in rabbit aortic endothelium: role in arachidonic acid-induced relaxation.

    PubMed

    Aggarwal, Nitin T; Holmes, Blythe B; Cui, Lijie; Viita, Helena; Yla-Herttuala, Seppo; Campbell, William B

    2007-02-01

    Endothelium-dependent vasorelaxation of the rabbit aorta is mediated by either nitric oxide (NO) or arachidonic acid (AA) metabolites from cyclooxygenase (COX) and 15-lipoxygenase (15-LO) pathways. 15-LO-1 metabolites of AA, 11,12,15-trihydroxyeicosatrienoic acid (THETA), and 15-hydroxy-11,12-epoxyeicosatrienoic acid (HEETA) cause concentration-dependent relaxation. We tested the hypothesis that in the 15-LO pathway of AA metabolism, 15-LO-1 is sufficient and is the rate-limiting step in inducing relaxations in rabbit aorta. Aorta and rabbit aortic endothelial cells were treated with adenoviruses containing human 15-LO-1 cDNA (Ad-15-LO-1) or beta-galactosidase (Ad-beta-Gal). Ad-15-LO-1-transduction increased the expression of a 75-kDa protein corresponding to 15-LO-1, detected by immunoblotting with an anti-human15-LO-1 antibody, and increased the production of HEETA and THETA from [(14)C]AA. Immunohistochemical studies on Ad-15-LO-1-transduced rabbit aorta showed the presence of 15-LO-1 in endothelial cells. Ad-15-LO-1-treated aortic rings showed enhanced relaxation to AA (max 31.7 +/- 3.2%) compared with Ad-beta-Gal-treated (max 12.7 +/- 3.2%) or control nontreated rings (max 13.1 +/- 1.6%) (P < 0.01). The relaxations in Ad-15-LO-1-treated aorta were blocked by the 15-LO inhibitor cinnamyl-3,4-dihydroxy-a-cyanocinnamate. Overexpression of 15-LO-1 in the rabbit aortic endothelium is sufficient to increase the production of the vasodilatory HEETA and THETA and enhance the relaxations to AA. This confirms the role of HEETA and THETA as endothelium-derived relaxing factors.

  16. Production of arachidonic acid metabolites by macrophages exposed in vitro to asbestos, carbonyl iron particles, or calcium ionophore.

    PubMed

    Kouzan, S; Brody, A R; Nettesheim, P; Eling, T

    1985-04-01

    Consequent to asbestos deposition, alveolar macrophages (AM) accumulate at alveolar duct bifurcations where they phagocytize fibers. Because phagocytosis can stimulate the release of arachidonic acid (AA) metabolites, the possibility that secretion of these powerful mediators of inflammation might be induced by chrysotile asbestos was investigated in vitro. Rat AM were treated in vitro with chrysotile asbestos, and the cyclooxygenase products--prostaglandins, thromboxane B2 (TXB2), 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT)--and lipoxygenase products--leukotrienes (LT), hydroxyeicosatetraenoic acids (HETE)--secreted in the medium were isolated by high-performance liquid chromatography. Composition of the AA metabolites released was compared with that from those stimulated by the calcium ionophore A 23187 (20 microM) and by another particulate phagocytic stimulus, i.e., carbonyl iron beads. Calcium ionophore stimulation induced a marked release of various AA metabolites in the medium from both the cyclooxygenase pathway (HHT, TXB2, and PGE2, in decreasing quantities, respectively) and the lipoxygenase pathway (LTB4, 5-HETE, 12-HETE, and LTC4). The major product was LTB4. Treatment of the macrophages with asbestos fibers induced the release of a similar array of AA metabolites, although there were smaller amounts of LTC4 and 12-HETE, but increased quantities of PGF2 alpha. A time course study showed a steady increase in metabolite production for 1 h, followed by a plateau. In addition, the amount of metabolites released was dependent on asbestos concentrations. Phagocytosis of iron beads induced the secretion of the same metabolites as asbestos stimulation, but in larger quantities, probably reflecting the lack of cytotoxicity of the particle.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Modulation of arachidonic acid metabolism by curcumin and related beta-diketone derivatives: effects on cytosolic phospholipase A(2), cyclooxygenases and 5-lipoxygenase.

    PubMed

    Hong, Jungil; Bose, Mousumi; Ju, Jihyeung; Ryu, Jae-Ha; Chen, Xiaoxin; Sang, Shengmin; Lee, Mao-Jung; Yang, Chung S

    2004-09-01

    Aberrant arachidonic acid metabolism is involved in the inflammatory and carcinogenic processes. In this study, we investigated the effects of curcumin, a naturally occurring chemopreventive agent, and related beta-diketone derivatives on the release of arachidonic acid and its metabolites in the murine macrophage RAW264.7 cells and in HT-29 human colon cancer cells. We also examined their effects on the catalytic activities and protein levels of related enzymes: cytosolic phospholipase A(2) (cPLA(2)), cyclooxygenases (COX) as well as 5-lipoxygenase (5-LOX). At 10 micro M, dibenzoylmethane (DBM), trimethoxydibenzoylmethane (TDM), tetrahydrocurcumin (THC) and curcumin effectively inhibited the release of arachidonic acid and its metabolites in lipopolysaccharide (LPS)-stimulated RAW cells and A23187-stimulated HT-29 cells. Inhibition of phosphorylation of cPLA(2), the activation process of this enzyme, rather than direct inhibition of cPLA(2) activity appears to be involved in the effect of curcumin. All the curcuminoids (10 micro M) potently inhibited the formation of prostaglandin E(2) (PGE(2)) in LPS-stimulated RAW cells. Curcumin (20 micro M) significantly inhibited LPS-induced COX-2 expression; this effect, rather than the catalytic inhibition of COX, may contribute to the decreased PGE(2) formation. Without LPS-stimulation, however, curcumin increased the COX-2 level in the macrophage cells. Studies with isolated ovine COX-1 and COX-2 enzymes showed that the curcuminoids had significantly higher inhibitory effects on the peroxidase activity of COX-1 than that of COX-2. Curcumin and THC potently inhibited the activity of human recombinant 5-LOX, showing estimated IC(50) values of 0.7 and 3 micro M, respectively. The results suggest that curcumin affects arachidonic acid metabolism by blocking the phosphorylation of cPLA(2), decreasing the expression of COX-2 and inhibiting the catalytic activities of 5-LOX. These activities may contribute to the anti

  18. Redirection of arachidonic acid metabolism by ICI D1542: effects on thrombus formation in the coronary artery of the anaesthetized dog.

    PubMed Central

    McAuliffe, S. J.; Moors, J. A.; Snow, H. M.; Wayne, M.; Jessup, R.

    1993-01-01

    1. The effects of simultaneous redirection of arachidonic acid metabolism, by inhibition of thromboxane A2 (TXA2) synthase and blockade of the platelet thromboxane A2 receptor (TP-receptor), was examined on the rate of thrombus formation in a stenosed coronary artery with damaged endothelium in an anaesthetized dog. 2. Redirection of arachidonic acid metabolism was achieved by intravenous doses of ICI D1542, a selective and potent inhibitor of TXA2 synthase and the TP-receptor. 3. Redirection of arachidonic acid metabolism was demonstrated in whole blood, stimulated ex vivo by collagen. The ED50 for inhibition of TXB2 production was 7.1 micrograms kg-1, i.v.; there were corresponding increases in the production of the eicosanoids prostaglandin D2 (PGD2), PGE2 and PGF2 alpha. 4. Thrombus formation was inhibited by D1542 (ED50 0.55 micrograms kg-1, i.v.), but could be restarted by an intravenous infusion of adrenaline (0.2-38 micrograms kg-1 min-1, i.v.). In the presence of the maximum effective dose of D1542 (1 mg kg-1, i.v.) a 190 fold increase in the infusion rate of adrenaline was required to restore thrombus formation. 5. In the presence of D1542, removal of endoperoxide metabolites by inhibition of cyclo-oxygenase with aspirin (5 mg kg-1, i.v.) caused thrombus formation to restart, indicating the ability of the endoperoxide metabolites to inhibit thrombus formation in vivo. 6. These results indicate that, in the stenosed and damaged coronary artery of the dog, redirection of arachidonic acid metabolism by D1542 is more effective at preventing thrombus formation than inhibition of cyclo-oxygenase by aspirin. PMID:8485629

  19. Food sources of arachidonic acid (PFA 20:4), listed in descending order by percentages of their contribution to intake, based on data from the National Health and Nutrition Examination Survey 2005-2006

    Cancer.gov

    Food sources of arachidonic acid (PFA 20:4), listed in descending order by percentages of their contribution to intake, based on data from the National Health and Nutrition Examination Survey 2005-2006

  20. Increased concentrations of arachidonic acid, prostaglandins E2, D2, and 6-oxo-F1 alpha, and histamine in human skin following UVA irradiation

    SciTech Connect

    Hawk, J.L.; Black, A.K.; Jaenicke, K.F.; Barr, R.M.; Soter, N.A.; Mallett, A.I.; Gilchrest, B.A.; Hensby, C.N.; Parrish, J.A.; Greaves, M.W.

    1983-06-01

    The buttock skin of clinically normal human subjects was subjected to approximately 2.5 minimal erythema doses of ultraviolet A irradiation. Deep red erythema developed during irradiation, faded slightly within the next few hours, increased to maximum intensity between 9-15 h, and decreased gradually thereafter although still persisting strongly at 48 h. Suction blister exudates were obtained at 0, 5, 9, 15, 24, and 48 h after irradiation as well as suction blister exudates from a contralateral control site and assayed for arachidonic acid, prostaglandins D2 and E2, and the prostacyclin breakdown product 6-oxo-prostaglandin F1 alpha by gas chromatography-mass spectrometry, and for histamine by radioenzyme assay. Increased concentrations of arachidonic acid and prostaglandins D2, E2, and 6-oxo-prostaglandin F1 alpha were found maximally between 5-9 h after irradiation, preceding the phase of maximal erythema. Elevations of histamine concentration occurred 9-15 h after irradiation, preceding and coinciding with the phase of maximal erythema. At 24 h, still at the height of the erythemal response, all values had returned to near control levels. Hence increased concentrations of arachidonic acid and its products from the cyclooxygenase pathway, and of histamine, accompany the early stages up to 24 h. A causal role in production of the erythema seems likely for these substances although other mediators are almost certainly involved.

  1. Differential age- and disease-related effects on the expression of genes related to the arachidonic acid signaling pathway in schizophrenia.

    PubMed

    Tang, Bin; Capitao, Cristina; Dean, Brian; Thomas, Elizabeth A

    2012-04-30

    We have previously identified differential effects of age on global brain gene expression profiles in subjects with schizophrenia compared to normal controls. Here, we have focused on age-related effects of genes associated with the arachidonic acid-related inflammation pathway. Linear correlation analysis of published microarray expression data reveal strong age- and cell-type- specific-effects on the expression of genes related to the arachidonic acid signaling pathway, which differed in control subjects compared to those with schizophrenia. Using real-time qPCR analysis, we validated age and disease effects of arachidonic acid-related genes in a large cohort of subjects with schizophrenia and matched controls (n=76 subjects in total). We found that levels of prostaglandin-endoperoxide synthase 1 (PTGS1; aka COX-1) and prostaglandin-endoperoxide receptor 3 (PTGER3) mRNA are increased, and levels of prostaglandin-endoperoxide synthase 2 (PTGS2; aka COX-2) mRNA are decreased, in older subjects with schizophrenia (> 40years of age) compared to matched normal controls or younger subjects with schizophrenia (< 40years of age). These findings contribute to the accumulating evidence suggesting that inflammatory processes in the CNS contribute to pathophysiology of schizophrenia and further suggest that age may be an important factor in the potential use of anti-inflammatory therapies.

  2. Effects of dynamic exercise on plasma arachidonic acid epoxides and diols in human volunteers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metabolites of the cytochrome P450 pathway may contribute to vasodilation of the vasculature of skeletal muscle during exercise. We determined effects of exercise intensity and duration on plasma concentrations of specific metabolites in the epoxyeicosatrienoic acid family. This allowed us to dete...

  3. Inhibition of serine/threonine phosphatase enhances arachidonic acid-induced [Ca2+]i via protein kinase A.

    PubMed

    Saino, Tomoyuki; Watson, Eileen L

    2009-01-01

    Arachidonic acid (AA) regulates intracellular calcium concentration ([Ca2+]i) in a variety of cell types including salivary cells. In the present study, the effects of serine/threonine phosphatases on AA-induced Ca(2+) signaling in mouse parotid acini were determined. Mice were euthanized with CO2. Treatment of acini with the serine/threonine phosphatase inhibitor calyculin A blocked both thapsigargin- and carbachol-induced Ca2+ entry but resulted in an enhancement of AA-induced Ca2+ release and entry. Effects were mimicked by the protein phosphatase-1 (PP1) inhibitor tautomycin but were inhibited by the PP2A inhibitor okadaic acid. The protein kinase A (PKA) inhibitor PKI(14-22) significantly attenuated AA-induced enhancement of Ca2+ release and entry in the presence of calyculin A, whereas it had no effect on calyculin A-induced inhibition of thapsigargin-induced Ca2+ responses. The ryanodine receptor (RyR) inhibitor, tetracaine, and StHt-31, a peptide known to competitively inhibit type II PKA regulatory subunit binding to PKA-anchoring protein (AKAP), abolished calyculin A enhancement of AA-induced Ca2+ release and entry. StHt-31 also abolished forskolin potentiation of 4-chloro-3-ethylphenol (4-CEP) and AA on Ca2+ release but had no effect on 8-(4-methoxyphenylthio)-2'-O-methyladenosine-3',5'-cAMP potentiation of 4-CEP responses. Results suggest that inhibition of PP1 results in an enhancement of AA-induced [Ca2+]i via PKA, AKAP, and RyRs.

  4. Lithium and the Other Mood Stabilizers Effective in Bipolar Disorder Target the Rat Brain Arachidonic Acid Cascade

    PubMed Central

    2014-01-01

    This Review evaluates the arachidonic acid (AA, 20:4n-6) cascade hypothesis for the actions of lithium and other FDA-approved mood stabilizers in bipolar disorder (BD). The hypothesis is based on evidence in unanesthetized rats that chronically administered lithium, carbamazepine, valproate, or lamotrigine each downregulated brain AA metabolism, and it is consistent with reported upregulated AA cascade markers in post-mortem BD brain. In the rats, each mood stabilizer reduced AA turnover in brain phospholipids, cyclooxygenase-2 expression, and prostaglandin E2 concentration. Lithium and carbamazepine also reduced expression of cytosolic phospholipase A2 (cPLA2) IVA, which releases AA from membrane phospholipids, whereas valproate uncompetitively inhibited in vitro acyl-CoA synthetase-4, which recycles AA into phospholipid. Topiramate and gabapentin, proven ineffective in BD, changed rat brain AA metabolism minimally. On the other hand, the atypical antipsychotics olanzapine and clozapine, which show efficacy in BD, decreased rat brain AA metabolism by reducing plasma AA availability. Each of the four approved mood stabilizers also dampened brain AA signaling during glutamatergic NMDA and dopaminergic D2 receptor activation, while lithium enhanced the signal during cholinergic muscarinic receptor activation. In BD patients, such signaling effects might normalize the neurotransmission imbalance proposed to cause disease symptoms. Additionally, the antidepressants fluoxetine and imipramine, which tend to switch BD depression to mania, each increased AA turnover and cPLA2 IVA expression in rat brain, suggesting that brain AA metabolism is higher in BD mania than depression. The AA hypothesis for mood stabilizer action is consistent with reports that low-dose aspirin reduced morbidity in patients taking lithium, and that high n-3 and/or low n-6 polyunsaturated fatty acid diets, which in rats reduce brain AA metabolism, were effective in BD and migraine patients. PMID

  5. Trans isomeric octadecenoic acids are related inversely to arachidonic acid and DHA and positively related to mead acid in umbilical vessel wall lipids.

    PubMed

    Decsi, Tamás; Boehm, Günther; Tjoonk, H M Ria; Molnár, Szilárd; Dijck-Brouwer, D A Janneke; Hadders-Algra, Mijna; Martini, Ingrid A; Muskiet, Frits A J; Boersma, E Rudy

    2002-10-01

    Long-chain PUFA play an important role in early human neurodevelopment. Significant inverse correlations were reported between values of trans isomeric and long-chain PUFA in plasma lipids of preterm infants and children aged 1-15 yr as well as in venous cord blood lipids of full-term infants. Here we report FA compositional data of cord blood vessel wall lipids in 308 healthy, full-term infants (gestational age: 39.7 +/- 1.2 wk, birth weight: 3528 +/- 429 g, mean +/- SD). The median (interquartile range) of the sum of 18-carbon trans FA was 0.22 (0.13) % w/w in umbilical artery and 0.16 (0.10) % w/w in umbilical vein lipids. Nonparametric correlation analysis showed significant inverse correlations between the sum of 18-carbon trans FA and both arachidonic acid and DHA in artery (r = -0.38, P < 0.01, and r = -0.20, P < 0.01) and vein (r = -0.36, P < 0.01, and -0.17, P < 0.01) wall lipids. In addition, the sum of 18-carbon trans FA was significantly positively correlated to Mead acid, a general indicator of EFA deficiency, in both artery (r = +0.35, P < 0.01) and vein (r = +0.31, P< 0.01) wall lipids. The present results obtained in a large group of full-term infants suggest that maternal trans FA intake is inversely associated with long-chain PUFA status of the infant at birth.

  6. Effects of Arachidonic Acid Supplementation on Acute Anabolic Signaling and Chronic Functional Performance and Body Composition Adaptations

    PubMed Central

    De Souza, Eduardo O.; Lowery, Ryan P.; Wilson, Jacob M.; Sharp, Matthew H.; Mobley, Christopher Brooks; Fox, Carlton D.; Lopez, Hector L.; Shields, Kevin A.; Rauch, Jacob T.; Healy, James C.; Thompson, Richard M.; Ormes, Jacob A.; Joy, Jordan M.; Roberts, Michael D.

    2016-01-01

    Background The primary purpose of this investigation was to examine the effects of arachidonic acid (ARA) supplementation on functional performance and body composition in trained males. In addition, we performed a secondary study looking at molecular responses of ARA supplementation following an acute exercise bout in rodents. Methods Thirty strength-trained males (age: 20.4 ± 2.1 yrs) were randomly divided into two groups: ARA or placebo (i.e. CTL). Then, both groups underwent an 8-week, 3-day per week, non-periodized training protocol. Quadriceps muscle thickness, whole-body composition scan (DEXA), muscle strength, and power were assessed at baseline and post-test. In the rodent model, male Wistar rats (~250 g, ~8 weeks old) were pre-fed with either ARA or water (CTL) for 8 days and were fed the final dose of ARA prior to being acutely strength trained via electrical stimulation on unilateral plantar flexions. A mixed muscle sample was removed from the exercised and non-exercised leg 3 hours post-exercise. Results Lean body mass (2.9%, p<0.0005), upper-body strength (8.7%, p<0.0001), and peak power (12.7%, p<0.0001) increased only in the ARA group. For the animal trial, GSK-β (Ser9) phosphorylation (p<0.001) independent of exercise and AMPK phosphorylation after exercise (p-AMPK less in ARA, p = 0.041) were different in ARA-fed versus CTL rats. Conclusions Our findings suggest that ARA supplementation can positively augment strength-training induced adaptations in resistance-trained males. However, chronic studies at the molecular level are required to further elucidate how ARA combined with strength training affect muscle adaptation. PMID:27182886

  7. Modulation of arachidonic acid release and membrane fluidity by albumin in vascular smooth muscle and endothelial cells.

    PubMed

    Beck, R; Bertolino, S; Abbot, S E; Aaronson, P I; Smirnov, S V

    1998-11-02

    Albumin is the major plasma protein circulating in blood. Albumin potently decreases capillary permeability, although the mechanisms are not understood completely. Albumin also effectively binds arachidonic acid (AA), which increases capillary permeability. To investigate the interactions of BSA and AA with the cell membrane, the effect of these substances on [3H]AA release and membrane fluidity was studied in vascular myocytes and endothelial cells. BSA (0.2 and 1 mg . mL-1) stimulated a significant release of [3H]AA from both intact rat aorta and cultured smooth muscle cells. This effect was not mimicked by gamma-globulin or myoglobin (both 1 mg . mL-1) in intact tissue. BSA, but not gamma-globulin and myoglobin, decreased the membrane fluidity (assessed as changes in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3, 5-hexatriene) in a concentration-dependent manner with a half-maximum concentration between 0.007 and 0.4 mg . mL-1 in both freshly isolated and cultured rat aortic myocytes and human umbilical vein endothelial cells. AA (1 to 200 micromol/L) caused the opposite effect, increasing membrane fluidity and antagonizing the effect of BSA. BSA modified at its arginine residues, which are thought to be important in AA binding, did not stimulate [3H]AA release and was significantly less potent than native BSA in altering the membrane fluidity. The effect of BSA can be explained by a high-affinity binding of AA to the protein and extraction of AA from the cell membrane. The interaction between BSA and AA could play a role in the regulation of vascular permeability.

  8. Arachidonic acid increases choline acetyltransferase activity in spinal cord neurons through a protein kinase C-mediated mechanism.

    PubMed

    Chalimoniuk, Malgorzata; King-Pospisil, Kelley; Pedersen, Ward A; Malecki, Andrzej; Wylegala, Edward; Mattson, Mark P; Hennig, Bernhard; Toborek, Michal

    2004-08-01

    Arachidonic acid (AA) plays an important role as a signaling factor in the CNS. Therefore, exposure to AA may affect cholinergic neurons in the spinal cord. To test this hypothesis, mRNA expression and activity of choline acetyltransferase (ChAT) was measured in cultured spinal cord neurons treated with increasing concentrations (0.1-10 microm) of AA. Exposure to AA increased mRNA levels and activity of ChAT in dose- and time-dependent manners. The most marked effect of AA on ChAT expression was observed in spinal cord neurons treated with 10 microm AA for 1 h. To study the mechanisms associated with these effects, ChAT mRNA levels and activity were measured in cultured spinal cord neurons exposed to AA and inhibitors of protein kinase C (PKC), such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dichloride (H-7) and chelerythrine. Inhibition of PKC completely prevented an AA-induced increase in ChAT expression. In addition, exposure of spinal cord neurons to phorbol-12-myristate-13-acetate (PMA), an activator of PKC, mimicked AA-induced stimulation of ChAT activity. The AA-mediated increase in ChAT mRNA levels and activity was also prevented by treatments with EGTA, indicating the role of calcium metabolism in induction of this enzyme. In contrast, treatments with 7-nitroindazole (7-NI, a specific inhibitor of neuronal nitric oxide synthase), sodium vanadate (NaV, a non-specific inhibitor of phosphatases), and N-acetyl-cysteine (NAC, an antioxidant) had no effect on AA-induced changes in ChAT activity. The protein synthesis inhibitor cycloheximide completely blocked AA-mediated increase in ChAT activity. These results indicate that the AA-evoked increase in ChAT activity in spinal cord neurons is mediated by PKC, presumably at the transcriptional level.

  9. IMAGING SIGNAL TRANSDUCTION VIA ARACHIDONIC ACID IN THE HUMAN BRAIN DURING VISUAL STIMULATION, BY MEANS OF POSITRON EMISSION TOMOGRAPHY

    PubMed Central

    Esposito, Giuseppe; Giovacchini, Giampiero; Der, Margaret; Liow, Jeih-San; Bhattacharjee, Abesh K.; Ma, Kaizong; Herscovitch, Peter; Channing, Michael; Eckelman, William C.; Hallett, Mark; Carson, Richard E.; Rapoport, Stanley I.

    2007-01-01

    Background Arachidonic acid (AA, 20:4n-6), an important second messenger, is released from membrane phospholipid following receptor mediated activation of phospholipase A2 (PLA2). This signaling process can be imaged in brain as a regional brain AA incorporation coefficient K*. Hypothesis K* will be increased in brain visual areas of subjects submitted to visual stimulation. Subjects and methods Regional values of K* were measured with positron emission tomography (PET), following the intravenous injection of [1-11C]AA, in 16 healthy volunteers subjected to visual stimulation at flash frequencies 2.9 Hz (8 subjects) or 7.8 Hz (8 subjects), compared with the dark (0 Hz) condition. Regional cerebral blood flow (rCBF) was measured with intravenous [15O]water under comparable conditions. Results During flash stimulation at 2.9 Hz or 7.8 Hz vs. 0 Hz, K* was increased significantly by 2.3–8.9% in Brodmann areas 17, 18 and 19, and in additional frontal, parietal and temporal cortical regions. rCBF was increased significantly by 3.1% – 22%, often in comparable regions. Increments at 7.8 Hz often exceeded those at 2.9 Hz for both K* and rCBF. Decrements in both parameters also were produced, particularly in frontal brain regions. Conclusions AA plays a role in signaling processes provoked by visual stimulation, since visual stimulation at flash frequencies of 2.9 and 7.8 Hz compared to 0 Hz modifies both K* for AA and rCBF in visual and related areas of the human brain. The two-stimulus condition paradigm of this study might be used with PET to image effects of other functional activations and of drugs on brain signaling via AA. PMID:17196833

  10. Ammodytoxins efficiently release arachidonic acid and induce apoptosis in a motoneuronal cell line in an enzymatic activity-dependent manner.

    PubMed

    Jenko-Pražnikar, Zala; Petan, Toni; Pungerčar, Jože

    2013-03-01

    Secreted phospholipases A2 (sPLA2s) are phospholipolytic enzymes and receptor ligands whose action affects cell death and survival. We have previously shown that ammodytoxin A (AtxA), a snake venom sPLA2, is rapidly internalized into motoneuronal NSC34 cells, inducing characteristic neurotoxic sPLA2 cell damage and apoptosis. In this study, we have analyzed the role of sPLA2 enzymatic activity, including arachidonic acid (AA) release, in the induction of motoneuronal apoptosis by AtxA and homologous recombinant sPLA2s with different enzymatic properties: an AtxA mutant (V31W) with very high enzymatic activity, enzymatically inactive S49-sPLA2 (ammodytin L, AtnL), its mutant (LW) with restored enzymatic activity, and non-toxic, enzymatically active sPLA2 (AtnI2). Addition of AA, AtxA, AtxA-V31W and AtnL-LW, but not AtnL and AtnI2, to NSC34 cells resulted in caspase-3 activation, DNA fragmentation and disruption of mitochondrial membrane potential, leading to a significant and rapid decrease in motoneuronal cell viability that was not observed in C2C12 myoblasts and HEK293 cells. AtxA, AtxA-V31W and AtnL-LW, but not AtnL and AtnI2, also liberated large amounts of AA specifically from motoneuronal cells, and this ability correlated well with the ability to induce apoptotic changes and decrease cell viability. The enzymatic activity of AtxA and similar sPLA2s is thus necessary, but not sufficient, for inducing motoneuronal apoptosis. This suggests that specific binding to the motoneuronal cell surface, followed by internalization and enzymatic activity-dependent induction of apoptosis, possibly as a consequence of extensive extra- and intracellular AA release, is necessary for Atx-induced motoneuronal cell death.

  11. Ethanol Promotes Chemically Induced Oral Cancer in Mice through Activation of the 5-Lipoxygenase Pathway of Arachidonic Acid Metabolism

    PubMed Central

    Guo, Yizhu; Wang, Xin; Zhang, Xinyan; Sun, Zheng; Chen, Xiaoxin

    2011-01-01

    Alcohol drinking is a known risk factor for oral cancer in humans. However, previous animal studies on the promoting effect of ethanol on oral carcinogenesis were inconclusive. It is necessary to develop an animal model with which the molecular mechanism of ethanol-related oral carcinogenesis may be elucidated in order to develop effective prevention strategies. In this study, mice were first treated with 4-nitroquinoline-1-oxide (4NQO, 100μg/ml in drinking water) for 8 weeks, and then given water or ethanol (8%) as the sole drink for another 16 weeks. During the experiment, 8% ethanol was well tolerated by mice. The incidence of squamous cell carcinoma (SCC) increased from 20% (8/41) to 43% (17/40; p<0.05). Expression of 5-lipoxygenase (5-Lox) and cyclooxygenase 2 (Cox-2) was increased in dysplasia and SCC of 4NQO-treated tongues, and further enhanced by ethanol. Using this mouse model, we further demonstrated that fewer cancers were induced in Alox5−/− mice, as were cell proliferation, inflammation, and angiogenesis in the tongue, as compared with Alox5+/+ mice. Interestingly, Cox-2 expression was induced by ethanol in knockout mice, while 5-Lox and leukotriene A4 hydrolase (LTA4H) expression and leukotriene B4 (LTB4) biosynthesis were dramatically reduced. Moreover, ethanol enhanced expression and nuclear localization of 5-Lox and stimulated LTB4 biosynthesis in human tongue SCC cells (SCC-15 and SCC-4) in vitro. In conclusion, this study clearly demonstrated that ethanol promoted 4NQO-induced oral carcinogenesis, at least in part, through further activation of the 5-Lox pathway of arachidonic acid metabolism. PMID:21881027

  12. The Cytotoxic Enterotoxin of Aeromonas hydrophila Induces Proinflammatory Cytokine Production and Activates Arachidonic Acid Metabolism in Macrophages

    PubMed Central

    Chopra, A. K.; Xu, X.-J.; Ribardo, D.; Gonzalez, M.; Kuhl, K.; Peterson, J. W.; Houston, C. W.

    2000-01-01

    An aerolysin-related cytotoxic enterotoxin (Act) of Aeromonas hydrophila possesses multiple biological activities, which include its ability to lyse red blood cells, destroy tissue culture cell lines, evoke a fluid secretory response in ligated intestinal loop models, and induce lethality in mice. The role of Act in the virulence of the organism has been demonstrated. In this study, we evaluated the potential of Act to induce production of proinflammatory cytokines associated with Act-induced tissue injury and Act's capacity to activate in macrophages arachidonic acid (AA) metabolism that leads to production of eicosanoids (e.g., prostaglandin E2 [PGE2]). Our data indicated that Act stimulated the production of tumor necrosis factor alpha and upregulated the expression of genes encoding interleukin-1β (IL-1β) and IL-6 in the murine macrophage cell line RAW264.7. Act also activated transcription of the gene encoding inducible nitric oxide synthase. Act evoked the production of PGE2 coupled to the cyclooxygenase-2 (COX-2) pathway. AA is a substrate for PGE2, and Act produced AA from phospholipids by inducing group V secretory phospholipase A2. We also demonstrated that Act increased cyclic AMP (cAMP) production in macrophages. cAMP, along with PGE2, could potentiate fluid secretion in animal models because of infiltration and activation of macrophages resulting from Act-induced tissue injury. After Act treatment of RAW cells, we detected an increased translocation of NF-κB and cAMP-responsive element binding protein (CREB) to the nucleus using gel shift assays. Act also upregulated production of antiapoptotic protein Bcl-2 in macrophages, suggesting a protective role for Bcl-2 against cell death induced by proinflammatory cytokines. The increased expression of genes encoding the proinflammatory cytokines, COX-2, and Bcl-2 appeared correlated with the activation of NF-κB and CREB. This is the first report of the detailed mechanisms of action of Act from A

  13. Low Na intake suppresses expression of CYP2C23 and arachidonic acid-induced inhibition of ENaC.

    PubMed

    Sun, Peng; Lin, Dao-Hong; Wang, Tong; Babilonia, Elisa; Wang, Zhijian; Jin, Yan; Kemp, Rowena; Nasjletti, Alberto; Wang, Wen-Hui

    2006-12-01

    We previously demonstrated that arachidonic acid (AA) inhibits epithelial Na channels (ENaC) through the cytochrome P-450 (CYP) epoxygenase-dependent pathway (34). In the present study, we tested the hypothesis that low Na intake suppresses the expression of CYP2C23, which is mainly responsible for converting AA to epoxyeicosatrienoic acid (EET) in the kidney (11) and attenuates the AA-induced inhibition of ENaC. Immunostaining showed that CYP2C23 is expressed in the Tamm-Horsfall protein (THP)-positive and aquaporin 2 (AQP2)-positive tubules. This suggests that CYP2C23 is expressed in the thick ascending limb (TAL) and collecting duct (CD). Na restriction significantly suppressed the expression of CYP2C23 in the TAL and CD. Western blot also demonstrated that the expression of CYP2C23 in renal cortex and outer medulla diminished in rats on Na-deficient diet (Na-D) but increased in those on high-Na diet (4%). Moreover, the content of 11,12-epoxyeicosatrienoic acid (EET) decreased in the isolated cortical CD from rats on Na-D compared with those on a normal-Na diet (0.5%). Patch-clamp study showed that application of 15 microM AA inhibited the activity of ENaC by 77% in the CCD of rats on a Na-D for 3 days. However, the inhibitory effect of AA on ENaC was significantly attenuated in rats on Na-D for 14 days. Furthermore, inhibition of CYP epoxygenase with MS-PPOH increased the ENaC activity in the CCD of rats on a control Na diet. We also used microperfusion technique to examine the effect of MS-PPOH on Na transport in the distal nephron. Application of MS-PPOH significantly increased Na absorption in the distal nephron of control rats but had no significant effect on Na absorption in rats on Na-D for 14 days. We conclude that low Na intake downregulates the activity and expression of CYP2C23 and attenuates the inhibitory effect of AA on Na transport.

  14. Evening primrose oil treatment corrects reduced conduction velocity but not depletion of arachidonic acid in nerve from streptozotocin-induced diabetic rats.

    PubMed

    Kuruvilla, R; Peterson, R G; Kincaid, J C; Eichberg, J

    1998-09-01

    The effects of evening primrose oil (EPO) treatment, a source of gamma-linolenic acid, on the proportions of arachidonoyl-containing molecular species (ACMS) in sciatic nerve phosphatidylcholine and phosphatidylethanolamine were determined in conjunction with alterations in nerve conduction velocity. Normal and diabetic rats were either untreated or fed a dietary supplement containing isocalorically equivalent amounts of either EPO or corn oil for the duration of the experiment. After 8 weeks of streptozotocin-induced diabetes, nerve conduction velocity was reduced 16% and this deficit was prevented by either EPO or corn oil treatment. Neither EPO nor corn oil supplementation significantly increased the depressed proportions of ACMS. The level of the linoleoyl-containing molecular species, 16:0/18:2, was elevated in the phospholipids from untreated diabetic rats and was further increased by EPO treatment. These results are consistent with decreased activity of the delta6 desaturase that is required for arachidonic acid synthesis in vivo, but suggests that an accompanying deficit in the subsequent delta5 desaturase-catalyzed reaction may be rate-limiting. These findings indicate that maintenance of normal ACMS levels is not required for prevention of diminished nerve conduction velocity and suggest that other factors influenced by an altered polyunsaturated fatty acid pattern, such as metabolites of linoleic acid or gamma-linolenic acid other than arachidonic acid, the energy state of the nerve or the degree of membrane fluidity may contribute to impaired nerve conduction velocity in diabetic neuropathy.

  15. Exogenous leukotriene B4 (LTB4) inhibits human neutrophil generation of LTB4 from endogenous arachidonic acid during opsonized zymosan phagocytosis.

    PubMed

    Fiedler, J; Wheelan, P; Henson, P M; Murphy, R C

    1998-10-01

    The effect of exogenous leukotriene B4 (LTB4) on opsonized zymosan-stimulated human neutrophil formation of 5-lipoxygenase products and arachidonic acid release was directly assessed using reverse-phase HPLC/tandem mass spectrometric methods for quantitation. Stable isotopically labeled LTB4, [1,2-13C2]LTB4, caused a dose-dependent inhibition of LTB4 production in isolated human neutrophils with significant inhibition (60 +/- 7% of control levels) when 0.12 nM [13C2]LTB4 was present. Production of 5-hydroxy-6,8,11,14-eicosatetraenoic acid and release of free arachidonic acid were also dose-dependently inhibited by exogenous LTB4. Metabolites of LTB4, 20-hydroxy-LTB4 and 3(S)-hydroxy-LTB4, also significantly reduced LTB4 production to levels as low as 10 +/- 6% and 10 +/- 7% of control levels, respectively, when present exogenously at 10 nM. Exogenous 5-hydroxy-6,8,11,14-eicosatetraenoic acid at concentrations as high as 10 nM produced no significant reduction in LTB4 biosynthesis during zymosan-stimulated human neutrophil production of LTB4. The inhibitory effect of LTB4 could be partially reversed by the LTB4 receptor antagonist U 75302. Furthermore, an alternative stimulus, N-formyl-methionyl-leucyl-phenylalanine (100 nM), did not inhibit the production of LTB4 in opsonized zymosan-stimulated human neutrophils. These results suggest that activation of the LTB4 receptor on the human neutrophil during phagocytosis limits the ultimate biosynthesis of LTB4. This autocrine effect is opposite to that observed when neutrophils have much of the signal transduction pathways bypassed when stimulated with calcium ionophore A23187 or treated with exogenous free arachidonic acid.

  16. Arachidonic acid triggers [Ca2+]i increases in rat round spermatids by a likely GPR activation, ERK signalling and ER/acidic compartments Ca2+ release.

    PubMed

    Paillamanque, Joaquin; Sanchez-Tusie, Ana; Carmona, Emerson M; Treviño, Claudia L; Sandoval, Carolina; Nualart, Francisco; Osses, Nelson; Reyes, Juan G

    2017-01-01

    Arachidonic acid (AA), a compound secreted by Sertoli cells (SC) in a FSH-dependent manner, is able to induce the release of Ca2+ from internal stores in round spermatids and pachytene spermatocytes. In this study, the possible site(s) of action of AA in round spermatids, the signalling pathways associated and the intracellular Ca2+ stores targeted by AA-induced signalling were pharmacologically characterized by measuring intracellular Ca2+ using fluorescent Ca2+ probes. Our results suggest that AA acts by interacting with a fatty acid G protein coupled receptor, initiating a G protein signalling cascade that may involve PLA2 and ERK activation, which in turn opens intracellular ryanodine-sensitive channels as well as NAADP-sensitive channels in acidic intracellular Ca2+ stores. The results presented here also suggest that AMPK and PKA modulate this AA-induced Ca2+ release from intracellular Ca2+ stores in round spermatids. We propose that unsaturated free fatty acid lipid signalling in the seminiferous tubule is a novel regulatory component of rat spermatogenesis.

  17. Arachidonic acid triggers [Ca2+]i increases in rat round spermatids by a likely GPR activation, ERK signalling and ER/acidic compartments Ca2+ release

    PubMed Central

    Paillamanque, Joaquin; Sanchez-Tusie, Ana; Carmona, Emerson M.; Treviño, Claudia L.; Sandoval, Carolina; Nualart, Francisco; Osses, Nelson

    2017-01-01

    Arachidonic acid (AA), a compound secreted by Sertoli cells (SC) in a FSH-dependent manner, is able to induce the release of Ca2+ from internal stores in round spermatids and pachytene spermatocytes. In this study, the possible site(s) of action of AA in round spermatids, the signalling pathways associated and the intracellular Ca2+ stores targeted by AA-induced signalling were pharmacologically characterized by measuring intracellular Ca2+ using fluorescent Ca2+ probes. Our results suggest that AA acts by interacting with a fatty acid G protein coupled receptor, initiating a G protein signalling cascade that may involve PLA2 and ERK activation, which in turn opens intracellular ryanodine-sensitive channels as well as NAADP-sensitive channels in acidic intracellular Ca2+ stores. The results presented here also suggest that AMPK and PKA modulate this AA-induced Ca2+ release from intracellular Ca2+ stores in round spermatids. We propose that unsaturated free fatty acid lipid signalling in the seminiferous tubule is a novel regulatory component of rat spermatogenesis. PMID:28192519

  18. Absorption and metabolism of ( sup 3 H)arachidonic and ( sup 14 C)linoleic acid in essential fatty acid-deficient rats

    SciTech Connect

    Hjelte, L.; Melin, T.; Nilsson, A.; Strandvik, B. )

    1990-07-01

    ({sup 3}H)arachidonic acid (20:4) and ({sup 14}C)linoleic acid (18:2) were fed in a triolein emulsion to essential fatty acid-deficient (EFAD) rats and to age-matched controls. Tissues were analyzed for radioactivity of different lipid classes after 1, 2, and 4 h. As in earlier studies, control rats retained more ({sup 3}H)20:4 than ({sup 14}C)18:2 in all organs except adipose tissue. In EFAD rats, recovery of ({sup 14}C)18:2 was increased in small intestine, liver, heart, and kidneys. In comparison to controls, EFAD rats retained much more ({sup 14}C)18:2 in phospholipids of these organs. The increase in the incorporation of both {sup 3}H and {sup 14}C into phosphatidylethanolamine was particularly pronounced. Another striking feature was the drastic increase in the retention after 4 h of {sup 14}C in cardiolipin, which is specifically located in the inner mitochondrial membrane. In contrast, incorporation of both {sup 3}H and {sup 14}C into phosphatidylinositol was decreased or unchanged in EFAD rats. Although fecal fat excretion was increased there was no evidence for a malabsorption or an increased retention in intestinal triacyglycerol of the radioactive fatty acids in EFAD rats. The proportion of ({sup 14}C)18:2 that had been converted to ({sup 14}C)20:4 was generally low but increased significantly with time in the liver and intestine of EFAD rats.

  19. Interrelated effects of dihomo-γ-linolenic and arachidonic acids, and sesamin on hepatic fatty acid synthesis and oxidation in rats.

    PubMed

    Ide, Takashi; Ono, Yoshiko; Kawashima, Hiroshi; Kiso, Yoshinobu

    2012-12-14

    Interrelated effects of dihomo-γ-linolenic acid (DGLA) and arachidonic acid (ARA), and sesamin, a sesame lignan, on hepatic fatty acid synthesis and oxidation were examined in rats. Rats were fed experimental diets supplemented with 0 or 2 g/kg sesamin (1:1 mixture of sesamin and episesamin), containing 100 g/kg of maize oil or fungal oil rich in DGLA or ARA for 16 d. Among the groups fed sesamin-free diets, oils rich in DGLA or ARA, especially the latter, compared with maize oil strongly reduced the activity and mRNA levels of various lipogenic enzymes. Sesamin, irrespective of the type of fat, reduced the parameters of lipogenic enzymes except for malic enzyme. The type of dietary fat was rather irrelevant in affecting hepatic fatty acid oxidation among rats fed the sesamin-free diets. Sesamin increased the activities of enzymes involved in fatty acid oxidation in all groups of rats given different fats. The extent of the increase depended on the dietary fat type, and the values became much higher with a diet containing sesamin and oil rich in ARA in combination than with a diet containing lignan and maize oil. Analyses of mRNA levels revealed that the combination of sesamin and oil rich in ARA compared with the combination of lignan and maize oil markedly increased the gene expression of various peroxisomal fatty acid oxidation enzymes but not mitochondrial enzymes. The enhancement of sesamin action on hepatic fatty acid oxidation was also confirmed with oil rich in DGLA but to a lesser extent.

  20. Evidence for the association of peroxidases with the antioxidant effect of p-coumaric acid in endothelial cells exposed to high glucose plus arachidonic acid.

    PubMed

    Lee, Seung Jin; Mun, Gyeong In; An, Sang Mi; Boo, Yong Chool

    2009-09-30

    Although many plant-derived phenolic compounds display antioxidant effects in biological systems, their mechanism of action remains controversial. In this study, the mechanism by which p-coumaric acid (p-CA) performs its antioxidant action was investigated in bovine aortic endothelial cells under oxidative stress due to high levels of glucose (HG) and arachidonic acid (AA), a free fatty acid. p-CA prevented lipid peroxidation and cell death due to HG+AA without affecting the production of reactive oxygen species. The antioxidant effect of p-CA was not decreased by buthionine-(S,R)-sulfoximine, an inhibitor of cellular GSH synthesis. In contrast, pretreatment with p-CA caused the induction of peroxidases that decomposed t-butyl hydroperoxide in a p-CA-dependent manner. Furthermore, the antioxidant effect of p-CA was significantly mitigated by methimazole, which was shown to inhibit the catalytic activity of 'p-CA peroxidases' in vitro. Therefore, it is suggested that the induction of these previously unidentified 'p-CA peroxidases' is responsible for the antioxidant effect of p-CA. [BMB reports 2009; 42(9): 561-567].

  1. Cross-talk between TLR4 and PPARγ pathways in the arachidonic acid-induced inflammatory response in pancreatic acini.

    PubMed

    Mateu, A; Ramudo, L; Manso, M A; De Dios, I

    2015-12-01

    Arachidonic acid (AA) is generally associated with inflammation in different settings. We assess the molecular mechanisms involved in the inflammatory response exerted by AA on pancreatic acini as an approach to acute pancreatitis (AP). Celecoxib (COX-2 inhibitor), TAK-242 (TLR4 inhibitor) and 15d-PGJ2 (PPARγ agonist) were used to ascertain the signaling pathways. In addition, we examine the effects of TAK-242 and 15d-PGJ2 on AP induced in rats by bile-pancreatic duct obstruction (BPDO). To carry out in vitro studies, acini were isolated from pancreas of control rats. Generation of PGE2 and TXB2, activation of pro-inflammatory pathways (MAPKs, NF-κB, and JAK/STAT3) and overexpression of CCL2 and P-selectin was found in AA-treated acini. In addition, AA up-regulated TLR4 and down-regulated PPARγ expression. Celecoxib prevented the up-regulation of CCL2 and P-selectin but did not show any effect on the AA-mediated changes in TLR4 and PPARγ expression. TAK-242, reduced the generation of AA metabolites and repressed both the cascade of pro-inflammatory events which led to CCL2 and P-selectin overexpression as well as the AA-induced PPARγ down-regulation. Thus, TLR4 acts as upstream activating pro-inflammatory and inhibiting anti-inflammatory pathways. 15d-PGJ2 down-regulated TLR4 expression and hence prevented the synthesis of AA metabolites and the inflammatory response mediated by them. Reciprocal negative cross-talk between TLR4 and PPARγ pathways is evidenced. In vivo experiments showed that TAK-242 and 15d-PGJ2 treatments reduced the inflammatory response in BPDO-induced AP. We conclude that through TLR4-dependent mechanisms, AA up-regulated CCL2 and P-selectin in pancreatic acini, partly mediated by the generation of PGE2 and TXB2, which activated pro-inflammatory pathways, but also directly by down-regulating PPARγ expression with anti-inflammatory activity. In vitro and in vivo studies support the role of TLR4 in AP and the use of TLR4 inhibitors and

  2. Fatty acids profile in a high cell density culture of arachidonic acid-rich Parietochloris incisa (Trebouxiophyceae, chlorophyta) exposed to high PFD

    NASA Astrophysics Data System (ADS)

    Liu, Jian-Guo; Cohen, Zvi; Richmond, Amos

    2002-06-01

    The changes in arachidonic acid (AA) and fatty acids profiles along the growth curve of Parietochloris incisa, a coccoid snow green alga, were studied in a 2.8 cm light-path flat photobiorcactor, exposed to strong photon flux density [PFD, 2400 μEmol/(m2·s)]. Sixteen fatty acids were identified by gas chromatography showing that AA was the dominant fatty acid (33% 41%) followed by linoleic acid (17% 21%). AA content was closely investigated with respect to total fatty acids (TFA), ash free dry weight (AFDW) of cell mass as well as total culture content. These parameters were influenced significantly in a similar manner by culture growth phase, i.e., slightly decreasing in the lag period, gradually increasing in the logarithmic phase, becoming maximal at the early stationary phase, starting to decrease at the late stationary phase, sharply dropping at the decline phase. The increase in AA per culture volume during the logarithmic phase was not only associated with the increase in AFDW but also connected with a corresponding increase in AA/TFA, TFA/AFDW as well as AA/AFDW. The sharp decrease in AA content of the culture during the decline phase was mainly due to the decrease in AA/TFA, TFA/AFDW and AA/AFDW, although AFDW declined only a small extent. Maximal AA concentration, obtained at the early stationary phase, was 900 mg/L culture volume, and the average daily net increase of AA during 9 days logarithmic growth was 1.7 g/(m2·day). Therefore, harvesting prior to the decline phase in a batch culture, or at steady state in continuous culture mode seems best for high AA production. The latter possibility was also further confirmed by continuous culture with 5 gradients of harvesting rate.

  3. Brain phospholipid arachidonic acid half-lives are not altered following 15 weeks of N-3 polyunsaturated fatty acid adequate or deprived diet

    PubMed Central

    Green, Joshua T.; Liu, Zhen; Bazinet, Richard P.

    2010-01-01

    Previous studies have infused radiolabeled arachidonic acid (AA) into rat brains and followed AA esterification into phospholipids for up to 24 h; however, the half-life of AA in rat brain phospholipids is unknown. Eighteen day old rats were fed either an n-3 PUFA adequate or deprived diet for 15 weeks. Following the 15 weeks, 40 µCi of [3H] AA was injected intracerebroventricularly into the right lateral ventricle using stereotaxic surgery and returned to their dietary treatment. From 4–120 days after [3H] AA administration, brains were collected for chemical analyses. The half-life of AA in rat brain phospholipids was 44 ± 4 days for the n-3 PUFA adequate group and 46 ± 4 days for the n-3 PUFA deprived group, which closely approximates the predicted half-life previously reported, based on the rate of entry from the plasma unesterified pool, suggesting the plasma unesterified pool is a major contributor to brain uptake of AA. Furthermore, unlike a previous report in which the half-life of brain phospholipid docosahexaenoic acid (DHA) was increased in n-3 PUFA deprived rats, n-3 PUFA deprivation did not significantly alter the AA half-life, suggesting different mechanisms exist to maintain brain concentrations of AA and DHA. PMID:19661256

  4. The effects of the oral administration of fish oil concentrate on the release and the metabolism of (/sup 14/C)arachidonic acid and (/sup 14/C)eicosapentaenoic acid by human platelets

    SciTech Connect

    Hirai, A.; Terano, T.; Hamazaki, T.; Sajiki, J.; Kondo, S.; Ozawa, A.; Fujita, T.; Miyamoto, T.; Tamura, Y.; Kumagai, A.

    1982-11-01

    It has been suggested by several investigators that eicosapentaenoic acid (C20:5 omega 3, EPA) might have anti-thrombotic effects. In this experiment, the effect of the oral administration of EPA rich fish oil concentrate on platelet aggregation and the release and the metabolism of (/sup 1 -14/C)arachidonic acid and ((U)-/sup 14/C)eicosapentaenoic acid by human platelets was studied. Eight healthy male subjects ingested 18 capsules of fish oil concentrate (EPA 1.4 g) per day for 4 weeks. Plasma and platelet concentrations of EPA markedly increased, while those of arachidonic acid (C20:4 omega 6, AA) and docosahexaenoic acid (C22:6 omega 3, DHA) did not change. Platelet aggregation induced by collagen and ADP was reduced. Collagen induced (/sup 14/C)thromboxane B2 (TXB2) formation from (/sup 14/C)AA prelabeled platelets decreased. There was no detectable formation of (/sup 14/C)TXB3 from (/sup 14/C)EPA prelabeled platelets, and the conversion of exogenous (/sup 14/C)EPA to (/sup 14/C)TXB3 was lower than that of (/sup 14/C)AA to (/sup 14/C)TXB2. The release of (/sup 14/C)AA from (/sup 14/C)AA prelabeled platelets by collagen was significantly decreased. These observations raise the possibility that the release of arachidonic acid from platelet lipids might be affected by the alteration of EPA content in platelets.

  5. Diffusion of intracerebrally injected (1-/sup 14/C)arachidonic acid and (2-/sup 3/H)glycerol in the mouse brain. Effects of ischemia and electroconvulsive shock

    SciTech Connect

    Pediconi, M.F.; Rodriguez de Turco, E.B.; Bazan, N.G.

    1982-12-01

    (2-/sup 3/H)Glycerol and (1-/sup 14/C)arachidonic acid were injected into the region of the frontal horn of the left ventricle of mice and were distributed rapidly throughout the brain. After 10 sec, most of the radioactive fatty acid was found in the hemisphere near the injection site; after 10 min, it was recovered in similar proportions in the cerebellum and brain stem. (2-/sup 3/H)Glycerol showed a heterogeneous distribution, with most of the label remaining in the left hemisphere even after 10 min. On a fresh weight basis, cerebrum, cerebellum, and brain stem were found to contain similar amounts of labeled glycerol. However, the amount of (1-/sup 14/C)arachidonate in cerebrum was only 50% of that recovered from cerebellum or brain stem. Brain ischemia or a single electroconvulsive shock reduced the spread of the label, producing an accumulation of radioactivity in the injected hemisphere, except for an increase in (2-/sup 3/H)glycerol in the brain stem during ischemia. Despite the significant decrease in available precursor in the cerebellum and brain stem after electroshock, the amount of label incorporated into lipids was not altered in these areas and only slightly diminished in the cerebrum.

  6. Exogenous arachidonic acid mediates permeability of human brain microvessel endothelial cells through prostaglandin E2 activation of EP3 and EP4 receptors.

    PubMed

    Dalvi, Siddhartha; Nguyen, Hieu H; On, Ngoc; Mitchell, Ryan W; Aukema, Harold M; Miller, Donald W; Hatch, Grant M

    2015-12-01

    The blood-brain barrier, formed by microvessel endothelial cells, is the restrictive barrier between the brain parenchyma and the circulating blood. Arachidonic acid (ARA; 5,8,11,14-cis-eicosatetraenoic acid) is a conditionally essential polyunsaturated fatty acid [20:4(n-6)] and is a major constituent of brain lipids. The current study examined the transport processes for ARA in confluent monolayers of human brain microvascular endothelial cells (HBMEC). Addition of radioactive ARA to the apical compartment of HBMEC cultured on Transwell(®) inserts resulted in rapid incorporation of radioactivity into the basolateral medium. Knock down of fatty acid transport proteins did not alter ARA passage into the basolateral medium as a result of the rapid generation of prostaglandin E2 (PGE2 ), an eicosanoid known to facilitate opening of the blood-brain barrier. Permeability following ARA or PGE2 exposure was confirmed by an increased movement of fluorescein-labeled dextran from apical to basolateral medium. ARA-mediated permeability was attenuated by specific cyclooxygenase-2 inhibitors. EP3 and EP4 receptor antagonists attenuated the ARA-mediated permeability of HBMEC. The results indicate that ARA increases permeability of HBMEC monolayers likely via increased production of PGE2 which acts upon EP3 and EP4 receptors to mediate permeability. These observations may explain the rapid influx of ARA into the brain previously observed upon plasma infusion with ARA. The blood-brain barrier, formed by microvessel endothelial cells, is a restrictive barrier between the brain parenchyma and the circulating blood. Radiolabeled arachidonic acid (ARA) movement across, and monolayer permeability in the presence of ARA, was examined in confluent monolayers of primary human brain microvessel endothelial cells (HBMECs) cultured on Transwell(®) plates. Incubation of HBMECs with ARA resulted in a rapid increase in HBMEC monolayer permeability. The mechanism was mediated, in part

  7. The effect of trinitrobenzene sulfonic acid on gut-derived smooth muscle cell arachidonic acid metabolism: role of endogenous prostanoids.

    PubMed

    Longo, W E; Smith, G S; Deshpande, Y; Reickenberg, C; Kaminski, D L

    1997-01-01

    The contribution of smooth muscle cells as a potential source of eicosanoid production during inflammatory states remains to be elucidated. We investigated the effect of trinitrobenzene sulfonic acid (TNB), a known pro-inflammatory agent, on jejunal smooth muscle cell eicosanoid production. Human gut-derived smooth muscle cells (HISM) were incubated with TNB for 1 hour. Additionally, some cells were preincubated with either dimethylthiourea, or indomethacin for 1 hour before exposure to identical concentrations of TNB. Incubation with TNB led to significant increases in PGE(2) and 6-keto PGF-1(alpha) release, but not leukotriene B(4) release; responses which were both inhibited by dimethylthiourea and indomethacin treatment. Our results suggest that gutderived smooth muscle cells may represent an important source of proinflammatory prostanoids but not leukotrienes during inflammatory states of the intestine. The inhibition of prostanoid activity by thiourea may be mediated by suppression of cyclooxygenase activity in this cell line.

  8. The effect of non-steroidal anti-inflammatory drugs on the metabolism of /sup 14/C-arachidonic acid by human gingival tissue in vitro

    SciTech Connect

    Elattar, T.M.; Lin, H.S.; Tira, D.E.

    1983-09-01

    We investigated the effect of non-steroidal anti-inflammatory drugs on prostaglandins (PGs) and 12-hydroxyeicosatetraenoic acid (12-HETE) formation by inflamed human gingival tissues. Gingival tissue homogenates were incubated with /sup 14/C-arachidonic acid in the presence of indomethacin, piroxicam, or ibuprofen, and the organic solvent extracts were chromatographed on silica gel plates with standards for radiometric assay. There was a significant negative trend between the doses (10(-7)-10(-3) M) of each of indomethacin, piroxicam, and ibuprofen, and the amounts of PGF2 alpha, PGE2, PGD2, and 15-keto-PGE2 produced. All three drugs have a significant inhibitory effect on PGs and 12-HETE production at 10(-3) M when compared with the control. The rank order effectiveness of the drugs, at 10(-3) M, on PG inhibition was indomethacin greater than piroxicam greater than ibuprofen, and on 12-HETE inhibition was indomethacin greater than ibuprofen greater than piroxicam.

  9. Role of intramitochondrial arachidonic acid and acyl-CoA synthetase 4 in angiotensin II-regulated aldosterone synthesis in NCI-H295R adrenocortical cell line.

    PubMed

    Mele, Pablo G; Duarte, Alejandra; Paz, Cristina; Capponi, Alessandro; Podestá, Ernesto J

    2012-07-01

    Although the role of arachidonic acid (AA) in angiotensin II (ANG II)- and potassium-stimulated steroid production in zona glomerulosa cells is well documented, the mechanism responsible for AA release is not fully described. In this study we evaluated the mechanism involved in the release of intramitochondrial AA and its role in the regulation of aldosterone synthesis by ANG II in glomerulosa cells. We show that ANG II and potassium induce the expression of acyl-coenzyme A (CoA) thioesterase 2 and acyl-CoA synthetase 4, two enzymes involved in intramitochondrial AA generation/export system well characterized in other steroidogenic systems. We demonstrate that mitochondrial ATP is required for AA generation/export system, steroid production, and steroidogenic acute regulatory protein induction. We also demonstrate the role of protein tyrosine phosphatases regulating acyl-CoA synthetase 4 and steroidogenic acute regulatory protein induction, and hence ANG II-stimulated aldosterone synthesis.

  10. Differential induction and suppression of potato 3-hydroxy-3-methylglutaryl coenzyme A reductase genes in response to Phytophthora infestans and to its elicitor arachidonic acid.

    PubMed Central

    Choi, D; Ward, B L; Bostock, R M

    1992-01-01

    Induction of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) is essential for the biosynthesis of sesquiterpenoid phytoalexins and steroid derivatives in Solanaceous plants following stresses imposed by wounding and pathogen infection. To better understand this complex step in stress-responsive isoprenoid synthesis, we isolated three classes of cDNAS encoding HMGR (hmg1, hmg2, and hmg3) from a potato tuber library using a probe derived from an Arabidopsis HMGR cDNA. The potato cDNAs had extensive homology in portions of the protein coding regions but had low homology in the 3' untranslated regions. RNA gel blot analyses using gene-specific probes showed that hmg1 was strongly induced in tuber tissue by wounding, but the wound induction was strongly suppressed by treatment of the tissue with the fungal elicitor arachidonic acid or by inoculation with an incompatible or compatible race of the fungal pathogen Phytophtora infestans. The hmg2 and hmg3 mRNAs also accumulated in response to wounding, but in contrast to hmg1, these mRNAs were strongly enhanced by arachidonic acid or inoculation. Inoculation with a compatible race of P. infestans resulted in similar patterns in HMGR gene expression of hmg2 and hmg3 except that the magnitude and rate of the changes in mRNA levels were reduced relative to the incompatible interaction. The differential regulation of members of the HMGR gene family may explain in part the previously reported changes in HMGR enzyme activities following wounding and elicitor treatment. The suppression of hmg1 and the enhancement of hmg2 and hmg3 transcript levels following elicitor treatment or inoculation with the incompatible race parallel the suppression in steroid and stimulation of sesquiterpenoid accumulations observed in earlier investigations. The results are discussed in relation to the hypothesis that there are discrete organizational channels for sterol and sesquiterpene biosynthesis in potato and other Solanaceous species. PMID

  11. Dietary n-6 PUFA deprivation for 15 weeks reduces arachidonic acid concentrations while increasing n-3 PUFA concentrations in organs of post-weaning male rats

    PubMed Central

    Igarashi, Miki; Gao, Fei; Kim, Hyung-Wook; Ma, Kaizong; Bell, Jane M.; Rapoport, Stanley I.

    2009-01-01

    Few studies have examined effects of feeding animals a diet deficient in n-6 polyunsaturated fatty acids (PUFAs) but with an adequate amount of n-3 PUFAs. To do this, we fed post-weaning male rats a control n-6 and n-3 PUFA adequate diet and an n-6 deficient diet for 15 weeks, and measured stable lipid and fatty acid concentrations in different organs. The deficient diet contained nutritionally essential linoleic acid (LA,18:2n-6) as 2.3% of total fatty acids (10% of the recommended minimum LA requirement for rodents) but no arachidonic acid (AA, 20:4n-6), and an adequate amount (4.8% of total fatty acids) of α-linolenic acid (18:3n-3). The deficient compared with adequate diet did not significantly affect body weight, but decreased testis weight by 10%. AA concentration was decreased significantly in serum (−86%), brain (−27%), liver (−68%), heart (−39%), testis (−25%), and epididymal adipose tissue (−77%). Eicosapentaenoic (20:5n-3) and docosahexaenoic acid (22:6n-3) concentrations were increased in all but adipose tissue, and the total monounsaturated fatty acid concentration was increased in all organs. The concentration of 20:3n-9, a marker of LA deficiency, was increased by the deficient diet, and serum concentrations of triacylglycerol, total cholesterol and total phospholipid were reduced. In summary, 15 weeks of dietary n-6 PUFA deficiency with n-3 PUFA adequacy significantly reduced n-6 PUFA concentrations in different organs of male rats, while increasing n-3 PUFA and monounsaturated fatty acid concentrations. This rat model could be used to study metabolic, functional and behavioral effects of dietary n-6 PUFA deficiency. PMID:19073280

  12. Simultaneous activation of p38 and JNK by arachidonic acid stimulates the cytosolic phospholipase A2-dependent synthesis of lipid droplets in human monocytes

    PubMed Central

    Guijas, Carlos; Pérez-Chacón, Gema; Astudillo, Alma M.; Rubio, Julio M.; Gil-de-Gómez, Luis; Balboa, María A.; Balsinde, Jesús

    2012-01-01

    Exposure of human peripheral blood monocytes to free arachidonic acid (AA) results in the rapid induction of lipid droplet (LD) formation by these cells. This effect appears specific for AA in that it is not mimicked by other fatty acids, whether saturated or unsaturated. LDs are formed by two different routes: (i) the direct entry of AA into triacylglycerol and (ii) activation of intracellular signaling, leading to increased triacylglycerol and cholesteryl ester formation utilizing fatty acids coming from the de novo biosynthetic route. Both routes can be dissociated by the arachidonyl-CoA synthetase inhibitor triacsin C, which prevents the former but not the latter. LD formation by AA-induced signaling predominates, accounting for 60–70% of total LD formation, and can be completely inhibited by selective inhibition of the group IVA cytosolic phospholipase A2α (cPLA2α), pointing out this enzyme as a key regulator of AA-induced signaling. LD formation in AA-treated monocytes can also be blocked by the combined inhibition of the mitogen-activated protein kinase family members p38 and JNK, which correlates with inhibition of cPLA2α activation by phosphorylation. Collectively, these results suggest that concomitant activation of p38 and JNK by AA cooperate to activate cPLA2α, which is in turn required for LD formation possibly by facilitating biogenesis of this organelle, not by regulating neutral lipid synthesis. PMID:22949356

  13. Isoliquiritigenin induces growth inhibition and apoptosis through downregulating arachidonic acid metabolic network and the deactivation of PI3K/Akt in human breast cancer

    SciTech Connect

    Li, Ying; Zhao, Haixia; Wang, Yuzhong; Zheng, Hao; Yu, Wei; Chai, Hongyan; Zhang, Jing; Falck, John R.; Guo, Austin M.; Yue, Jiang; Peng, Renxiu; Yang, Jing

    2013-10-01

    Arachidonic acid (AA)-derived eicosanoids and its downstream pathways have been demonstrated to play crucial roles in growth control of breast cancer. Here, we demonstrate that isoliquiritigenin, a flavonoid phytoestrogen from licorice, induces growth inhibition and apoptosis through downregulating multiple key enzymes in AA metabolic network and the deactivation of PI3K/Akt in human breast cancer. Isoliquiritigenin diminished cell viability, 5-bromo-2′-deoxyuridine (BrdU) incorporation, and clonogenic ability in both MCF-7 and MDA-MB-231cells, and induced apoptosis as evidenced by an analysis of cytoplasmic histone-associated DNA fragmentation, flow cytometry and hoechst staining. Furthermore, isoliquiritigenin inhibited mRNA expression of multiple forms of AA-metabolizing enzymes, including phospholipase A2 (PLA2), cyclooxygenases (COX)-2 and cytochrome P450 (CYP) 4A, and decreased secretion of their products, including prostaglandin E{sub 2} (PGE{sub 2}) and 20-hydroxyeicosatetraenoic acid (20-HETE), without affecting COX-1, 5-lipoxygenase (5-LOX), 5-lipoxygenase activating protein (FLAP), and leukotriene B{sub 4} (LTB{sub 4}). In addition, it downregulated the levels of phospho-PI3K, phospho-PDK (Ser{sup 241}), phospho-Akt (Thr{sup 308}), phospho-Bad (Ser{sup 136}), and Bcl-x{sub L} expression, thereby activating caspase cascades and eventually cleaving poly(ADP-ribose) polymerase (PARP). Conversely, the addition of exogenous eicosanoids, including PGE{sub 2}, LTB{sub 4} and a 20-HETE analog (WIT003), and caspase inhibitors, or overexpression of constitutively active Akt reversed isoliquiritigenin-induced apoptosis. Notably, isoliquiritigenin induced growth inhibition and apoptosis of MDA-MB-231 human breast cancer xenografts in nude mice, together with decreased intratumoral levels of eicosanoids and phospho-Akt (Thr{sup 308}). Collectively, these data suggest that isoliquiritigenin induces growth inhibition and apoptosis through downregulating AA metabolic

  14. Co-supplementation of healthy women with fish oil and evening primrose oil increases plasma docosahexaenoic acid, gamma-linolenic acid and dihomo-gamma-linolenic acid levels without reducing arachidonic acid concentrations.

    PubMed

    Geppert, Julia; Demmelmair, Hans; Hornstra, Gerard; Koletzko, Berthold

    2008-02-01

    Fish oil supplementation during pregnancy not only improves maternal and neonatal DHA status, but often reduces gamma-linolenic acid (GLA), dihomo-GLA (DGLA), and arachidonic acid (ARA) levels also, which may compromise foetal and infant development. The present study investigated the effects of a fish oil/evening primrose oil (FSO/EPO) blend (456 mg DHA/d and 353 mg GLA/d) compared to a placebo (mixture of habitual dietary fatty acids) on the plasma fatty acid (FA) composition in two groups of twenty non-pregnant women using a randomised, double-blind, placebo-controlled parallel design. FA were quantified in plasma total lipids, phospholipids, cholesterol esters, and TAG at weeks 0, 4, 6 and 8. After 8 weeks of intervention, percentage changes from baseline values of plasma total lipid FA were significantly different between FSO/EPO and placebo for GLA (+49.9 % v. +2.1 %, means), DGLA (+13.8 % v. +0.7 %) and DHA (+59.6 % v. +5.5 %), while there was no significant difference for ARA ( - 2.2 % v. - 5.9 %). FA changes were largely comparable between plasma lipid fractions. In both groups three subjects reported mild adverse effects. As compared with placebo, FSO/EPO supplementation did not result in any physiologically relevant changes of safety parameters (blood cell count, liver enzymes). In women of childbearing age the tested FSO/EPO blend was well tolerated and appears safe. It increases plasma GLA, DGLA, and DHA levels without impairing ARA status. These data provide a basis for testing this FSO/EPO blend in pregnant women for its effects on maternal and neonatal FA status and infant development.

  15. Evidence for the essentiality of arachidonic and docosahexaenoic acid in the postnatal maternal and infant diet for the development of the infant's immune system early in life.

    PubMed

    Richard, Caroline; Lewis, Erin D; Field, Catherine J

    2016-05-01

    Long-chain polyunsaturated fatty acids (LCPUFA), especially the balance between arachidonic (AA) and docosahexaenoic (DHA) acids are known to have important immunomodulatory roles during the postnatal period when the immune system is rapidly developing. AA and DHA are required in infant formula in many countries but are optional in North America. The rationale for adding these LCPUFA to full-term formula is based on their presence in breast milk and randomized controlled studies that suggest improved cognitive function in preterm infants, but results are more variable in full-term infants. Recently, the European Food Safety Authority has proposed, based on a lack of functional evidence, that AA is not required in infant formula for full-term infants during the first year of life but DHA should remain mandatory. The purpose of this review is to review the evidence from epidemiological and intervention studies regarding the essentiality of AA and DHA in the postnatal infant and maternal diet (breast-feeding) for the immune system development early in life. Although studies support the essentiality of DHA for the immune system development, more research is needed to rule out the essentiality of AA. Nevertheless, intervention studies have demonstrated improvement in many markers of immune function in infants fed formula supplemented with AA and DHA compared with unsupplemented formula, which appears to consistently result in beneficial health outcomes including reduction in the risk of developing allergic and atopic disease early in life.

  16. AKAP150, a switch to convert mechano-, pH- and arachidonic acid-sensitive TREK K(+) channels into open leak channels.

    PubMed

    Sandoz, Guillaume; Thümmler, Susanne; Duprat, Fabrice; Feliciangeli, Sylvain; Vinh, Joëlle; Escoubas, Pierre; Guy, Nicolas; Lazdunski, Michel; Lesage, Florian

    2006-12-13

    TREK channels are unique among two-pore-domain K(+) channels. They are activated by polyunsaturated fatty acids (PUFAs) including arachidonic acid (AA), phospholipids, mechanical stretch and intracellular acidification. They are inhibited by neurotransmitters and hormones. TREK-1 knockout mice have impaired PUFA-mediated neuroprotection to ischemia, reduced sensitivity to volatile anesthetics and altered perception of pain. Here, we show that the A-kinase-anchoring protein AKAP150 is a constituent of native TREK-1 channels. Its binding to a key regulatory domain of TREK-1 transforms low-activity outwardly rectifying currents into robust leak conductances insensitive to AA, stretch and acidification. Inhibition of the TREK-1/AKAP150 complex by Gs-coupled receptors such as serotonin 5HT4sR and noradrenaline beta2AR is as extensive as for TREK-1 alone, but is faster. Inhibition of TREK-1/AKAP150 by Gq-coupled receptors such as serotonin 5HT2bR and glutamate mGluR5 is much reduced when compared to TREK-1 alone. The association of AKAP150 with TREK channels integrates them into a postsynaptic scaffold where both G-protein-coupled membrane receptors (as demonstrated here for beta2AR) and TREK-1 dock simultaneously.

  17. Detection in vivo of a Novel Endogenous Etheno DNA Adduct Derived from Arachidonic Acid and the Effects of Antioxidants on Its Formation

    PubMed Central

    Cruz, Idalia M.; Pondicherry, Sharanya R.; Fernandez, Aileen; Schultz, Casey L.; Yang, Peiying; Pan, Jishen; Desai, Dhimant; Krzeminski, Jacek; Amin, Shantu; Christov, Plamen P.; Hara, Yukihiko; Chung, Fung-Lung

    2014-01-01

    Previous studies showed that the 7-(1′,2′-dihydroxyheptyl) substituted etheno DNA adducts are products from reactions with epoxide of (E)-4-hydroxy-2-nonenal (HNE), an oxidation product of ω-6 polyunsaturated fatty acids (PUFAs). In this work, we report the detection of 7-(1′,2′-dihydroxyheptyl)-1,N6-ethenodeoxyadenosine (DHHedA) in rodent and human tissues by two independent methods: a 32P-postlabeling/HPLC method and an isotope dilution liquid chromatography electrospray ionization tandem mass spectrometry method (ID-LC-ESI-MS/MS), demonstrating for the first time that DHHedA is a background DNA lesion in vivo. We showed that DHHedA can be formed upon incubation of arachidonic acid (AA) with deoxyadenosine (dA), supporting the notion that ω-6 PUFAs are the endogenous source of DHHedA formation. Because cyclic adducts are derived from the oxidation of PUFAs, we subsequently examined the effects of antioxidants, α-lipoic acid, Polyphenon E and vitamin E, on the formation of DHHedA and γ-hydroxy-1,N2-propanodeoxyguanosine (γ-OHPdG), a widely studied acrolein-derived adduct arising from oxidized PUFAs, in the livers of Long Evans Cinnamon (LEC) rats. LEC rats are inflicted with elevated lipid peroxidation and prone to the development of hepatocellular carcinomas. The results showed that while the survival of LEC rats increased significantly by α-lipoic acid, none of the antioxidants inhibited the formation of DHHedA and only Polyphenon E decreased the formation of γ-OHPdG. In contrast, vitamin E caused a significant increase in the formation of both γ-OHPdG and DHHedA in the livers of LEC rats. PMID:24816294

  18. AD6 (8-monochloro-3-beta-diethylamino-ethyl-4-methyl-7-ethoxycarbonyl-meth oxy coumarin) inhibits the release of arachidonic acid in human platelets stimulated by thrombin

    SciTech Connect

    Porcellati, S.; Costantini, V.; Prosdocimi, M.; Pistolesi, R.; Porrovecchio, P.; Nenci, G.G.; Goracci, G.

    1987-07-01

    The coumarin derivative AD6 is known to inhibit platelet aggregation and release and it possesses vasodilatory properties on coronary arteries of laboratory animals. Furthermore, the inhibition of the production of TxB2 from endogenous substrates after stimulation of human platelets with collagen has been demonstrated. The present report demonstrates that AD6 inhibits the production of labeled arachidonic acid and diglycerides from phospholipids of platelets stimulated with thrombin. This effect is dose-dependent and is already evident at a concentration of the drug (25 microM) which is unable to prevent the aggregation. Apparently, AD6 inhibits the release of arachidonic acid from phosphatidylinositol and choline phosphoglycerides which are the main sources of the substrate for the synthesis of prostaglandins and thromboxanes.

  19. Prostaglandin E2 and the protein kinase A pathway mediate arachidonic acid induction of c-fos in human prostate cancer cells

    NASA Technical Reports Server (NTRS)

    Chen, Y.; Hughes-Fulford, M.

    2000-01-01

    Arachidonic acid (AA) is the precursor for prostaglandin E2 (PGE2) synthesis and increases growth of prostate cancer cells. To further elucidate the mechanisms involved in AA-induced prostate cell growth, induction of c-fos expression by AA was investigated in a human prostate cancer cell line, PC-3. c-fos mRNA was induced shortly after addition of AA, along with a remarkable increase in PGE2 production. c-fos expression and PGE2 production induced by AA was blocked by a cyclo-oxygenase inhibitor, flurbiprofen, suggesting that PGE2 mediated c-fos induction. Protein kinase A (PKA) inhibitor H-89 abolished induction of c-fos expression by AA, and partially inhibited PGE2 production. Protein kinase C (PKC) inhibitor GF109203X had no significant effect on c-fos expression or PGE2 production. Expression of prostaglandin (EP) receptors, which mediate signal transduction from PGE2 to the cells, was examined by reverse transcription polymerase chain reaction in several human prostate cell lines. EP4 and EP2, which are coupled to the PKA signalling pathway, were expressed in all cells tested. Expression of EP1, which activates the PKC pathway, was not detected. The current study showed that induction of the immediate early gene c-fos by AA is mediated by PGE2, which activates the PKA pathway via the EP2/4 receptor in the PC-3 cells.

  20. Menopause-induced uterine epithelium atrophy results from arachidonic acid/prostaglandin E2 axis inhibition-mediated autophagic cell death

    PubMed Central

    Zhou, Shengtao; Zhao, Linjie; Yi, Tao; Wei, Yuquan; Zhao, Xia

    2016-01-01

    Women experience menopause later in life. Menopause is characterized by dramatically decreased circulating estrogen level secondary to loss of ovarian function and atrophic state of genital organs. However, the molecular mechanisms for this process are not fully understood. In this study, we aimed to investigate the potential molecular mechanisms that underlie menopause-induced uterine endometrial atrophy. Our data showed that autophagy was activated in the uterine epithelial cells of both ovariectomized rats and peri-menopausal females. Endoplasmic reticulum (ER) stress occurred even prior to autophagy induction. Integrated bioinformatics analysis revealed that ER stress induced downstream decreased release of arachidonic acid (AA) and downregulation of AA/prostaglandin E2 (PGE2) axis, which led to Akt/mTOR signaling pathway inactivation. Consequently, autophagosomes were recruited and LC3-dependent autophagy was induced in uterine epithelial cells. Treatment with exogenous E2, PGE2, salubrinal or RNAi-mediated silencing of key autophagy genes could effectively counteract estrogen depletion-induced autophagy. Collectively, autophagy is a critical regulator of the uterine epithelium that accounts for endometrial atrophy after menopause. PMID:27506466

  1. A postsynaptic transient K+ current modulated by arachidonic acid regulates synaptic integration and threshold for LTP induction in hippocampal pyramidal cells

    PubMed Central

    Ramakers, Geert M. J.; Storm, Johan F.

    2002-01-01

    Voltage-gated ion channels in the dendrites and somata of central neurons can modulate the impact of synaptic inputs. One of the ionic currents contributing to such modulation is the fast inactivating A-type potassium current (IA). We have investigated the role of IA in synaptic integration in rat CA1 pyramidal cells by using arachidonic acid (AA) and heteropodatoxin-3 (HpTX3), a selective blocker of the Kv4 channels underlying much of the somatodendritic IA. AA and HpTX3 each reduced IA by 60–70% (measured at the soma) and strongly enhanced the amplitude and summation of excitatory postsynaptic responses, thus facilitating action potential discharges. HpTX3 also reduced the threshold for induction of long-term potentiation. We conclude that the postsynaptic IA is activated during synaptic depolarizations and effectively regulates the somatodendritic integration of high-frequency trains of synaptic input. AA, which can be released by such input, enhances synaptic efficacy by suppressing IA, which could play an important role in frequency-dependent synaptic plasticity in the hippocampus. PMID:12114547

  2. Chronic dietary n-6 PUFA deprivation leads to conservation of arachidonic acid and more rapid loss of DHA in rat brain phospholipids[S

    PubMed Central

    Lin, Lauren E.; Chen, Chuck T.; Hildebrand, Kayla D.; Liu, Zhen; Hopperton, Kathryn E.; Bazinet, Richard P.

    2015-01-01

    To determine how the level of dietary n-6 PUFA affects the rate of loss of arachidonic acid (ARA) and DHA in brain phospholipids, male rats were fed either a deprived or adequate n-6 PUFA diet for 15 weeks postweaning, and then subjected to an intracerebroventricular infusion of 3H-ARA or 3H-DHA. Brains were collected at fixed times over 128 days to determine half-lives and the rates of loss from brain phospholipids (Jout). Compared with the adequate n-6 PUFA rats, the deprived n-6-PUFA rats had a 15% lower concentration of ARA and an 18% higher concentration of DHA in their brain total phospholipids. Loss half-lives of ARA in brain total phospholipids and fractions (except phosphatidylserine) were longer in the deprived n-6 PUFA rats, whereas the Jout was decreased. In the deprived versus adequate n-6 PUFA rats, the Jout of DHA was higher. In conclusion, chronic n-6 PUFA deprivation decreases the rate of loss of ARA and increases the rate of loss of DHA in brain phospholipids. Thus, a low n-6 PUFA diet can be used to target brain ARA and DHA metabolism. PMID:25477531

  3. Understanding traditional Chinese medicine anti-inflammatory herbal formulae by simulating their regulatory functions in the human arachidonic acid metabolic network.

    PubMed

    Gu, Shuo; Yin, Ning; Pei, Jianfeng; Lai, Luhua

    2013-07-01

    Through history, traditional Chinese medicine (TCM) has adopted oriental philosophical practices of drug combination and interaction to address human diseases. To investigate this from a systems biology point of view, we analysed 28 TCM herbs for their anti-inflammatory function, using molecular docking and arachidonic acid (AA) metabolic network simulation. The inhibition potential of each herb toward five essential enzymes as well as their possible side effects were examined. Three commonly prescribed anti-inflammatory formulae were simulated to discover the combinatorial properties of each contained herb in regulating the whole metabolic network. We discovered that different ingredients of a formula tend to inhibit different targets, which almost covered all the targets in the whole network. We also found that herbal combinations could achieve the same therapeutic effect at lower doses compared with individual usage. New herbal combinations were also predicted based on the inhibition potentials and two types of synergistic drug combinations of TCM theory were discussed from the perspective of systems biology. Using this combined approach of molecular docking and network simulation, we were able to computationally elucidate the combinatorial effects of TCM to intervene disease networks. We expect novel TCM formulae or modern drug combinations to be developed based on this research.

  4. Arachidonic acid alters tomato HMG expression and fruit growth and induces 3-hydroxy-3-methylglutaryl coenzyme A reductase-independent lycopene accumulation

    SciTech Connect

    Rodriguez-Concepcion, M.; Gruissem, W.

    1999-01-01

    Regulation of isoprenoid end-product synthesis required for normal growth and development in plants is not well understood. To investigate the extent to which specific genes for the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) are involved in end-product regulation, the authors manipulated expression of the HMG1 and HMG2 genes in tomato (Lycopersicon esculentum) fruit using arachidonic acid (AA). In developing young fruit AA blocked fruit growth, inhibited HMG1, and activated HMG2 expression. These results are consistent with other reports indicating that HMG1 expression is closely correlated with growth processes requiring phytosterol production. In mature-green fruit AA strongly induced the expression of HMG2, PSY1 (the gene for phytoene synthase), and lycopene accumulation before the normal onset of carotenoid synthesis and ripening. The induction of lycopene synthesis was not blocked by inhibition of HMGR activity using mevinolin, suggesting that cytoplasmic HMGR is not required for carotenoid synthesis. Their results are consistent with the function of an alternative plastid isoprenoid pathway (the Rohmer pathway) that appears to direct the production of carotenoids during tomato fruit ripening.

  5. Arachidonic acid affects biofilm formation and PGE2 level in Candida albicans and non-albicans species in presence of subinhibitory concentration of fluconazole and terbinafine.

    PubMed

    Mishra, Nripendra Nath; Ali, Shakir; Shukla, Praveen K

    2014-01-01

    Candida albicans utilizes arachidonic acid (AA) released during the course of infection (Candidiasis) from phospholipids of infected host cell membranes and synthesizes extracellular prostaglandin(s) which play an important role in hyphae formation and host cell damage. C. albicans biofilms secrete significantly more prostaglandin(s) and evidence suggests that Candida biofilms have dramatically reduced susceptibility to majority of antifungal drugs. AA influences the saturation level of lipids and fluidity of yeast cell membranes. Therefore the aim of this study was to evaluate the effect of AA alone or in combination with antifungal agents on biofilm formation and production of prostaglandin (PGE2) in C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, and C. albicans amphotericin B resistant strain (AmBR). Maximum biofilm formation was found to be in the case of C. albicans compared to C. non-albicans species. However, among the non-albicans species C. tropicalis exhibited highest biofilm formation. Treatment with AA in combination with subinhibitory concentrations of fluconazole and terbinafine separately exhibited significant (p<0.05) reduction in biofilm formation against C. glabrata, C. parapsilosis, C. tropicalis and AmBR as compared to their individual effect. Further, these two antifungal agents in combination with AA caused an increase in production of prostaglandin from fungal cell itself which was significant (p<0.05) in case of all the strains tested.

  6. Nrf2 is crucial for the down-regulation of Cyp7a1 induced by arachidonic acid in Hepg2 cells.

    PubMed

    Zhang, Jin-Ming; Wang, Xing-He; Hao, Li-Hong; Wang, He; Zhang, Xiu-Ying; Muhammad, Ishfaq; Qi, Yue; Li, Guang-Liang; Sun, Xiao-Qi

    2017-03-07

    In former research, cyp7a1 expression was decreased but Nrf2 transcription and hepatic arachidonic acid (AA) concentration were increased in high-fat diet fed mice. This study aims to investigate the influence of AA in CYP7A1 expression and the role of Nrf2 in regulating CYP7A1 in the process. HepG2 cells were administered with different concentrations of AA. Nrf2 and CYP7A1 expressions were analyzed by real-time PCR and western blot. Nrf2 silenced and over-expressed cell models were constructed by Nrf2 siRNA and eukaryotic expression vector transient transfections and were used to investigate the role of Nrf2 in regulating CYP7A1 following AA administration. The results showed that Nrf2 was increased dose-dependently but CYP7A1 was decreased dose-dependently in cells treated with increasing concentrations of AA. The expression of CYP7A1 was increased by Nrf2 silence and was decreased by Nrf2 over-expression in HepG2 cells treated with different concentrations of AA. In conclusion, Nrf2 plays a significant role in the down-regulation of CYP7A1 induced by AA in HepG2 cells.

  7. Development of a nuclear transformation system for Oleaginous Green Alga Lobosphaera (Parietochloris) incisa and genetic complementation of a mutant strain, deficient in arachidonic acid biosynthesis.

    PubMed

    Zorin, Boris; Grundman, Omer; Khozin-Goldberg, Inna; Leu, Stefan; Shapira, Michal; Kaye, Yuval; Tourasse, Nicolas; Vallon, Olivier; Boussiba, Sammy

    2014-01-01

    Microalgae are considered a promising source for various high value products, such as carotenoids, ω-3 and ω-6 polyunsaturated fatty acids (PUFA). The unicellular green alga Lobosphaera (Parietochloris) incisa is an outstanding candidate for the efficient phototrophic production of arachidonic acid (AA), an essential ω-6 PUFA for infant brain development and a widely used ingredient in the baby formula industry. Although phototrophic production of such algal products has not yet been established, estimated costs are considered to be 2-5 times higher than competing heterotrophic production costs. This alga accumulates unprecedented amounts of AA within triacylglycerols and the molecular pathway of AA biosynthesis in L. incisa has been previously elucidated. Thus, progress in transformation and metabolic engineering of this high value alga could be exploited for increasing the efficient production of AA at competitive prices. We describe here the first successful transformation of L. incisa using the ble gene as a selection marker, under the control of the endogenous RBCS promoter. Furthermore, we have succeeded in the functional complementation of the L. incisa mutant strain P127, containing a mutated, inactive version of the delta-5 (Δ5) fatty acid desaturase gene. A copy of the functional Δ5 desaturase gene, linked to the ble selection marker, was transformed into the P127 mutant. The resulting transformants selected for zeocine resistant, had AA biosynthesis partially restored, indicating the functional complementation of the mutant strain with the wild-type gene. The results of this study present a platform for the successful genetic engineering of L. incisa and its long-chain PUFA metabolism.

  8. High extracellular Ca2+ stimulates Ca2+-activated Cl- currents in frog parathyroid cells through the mediation of arachidonic acid cascade.

    PubMed

    Okada, Yukio; Imendra, Kotapola G; Miyazaki, Toshihiro; Hotokezaka, Hitoshi; Fujiyama, Rie; Toda, Kazuo

    2011-04-29

    Elevation of extracellular Ca(2+) concentration induces intracellular Ca(2+) signaling in parathyroid cells. The response is due to stimulation of the phospholipase C/Ca(2+) pathways, but the direct mechanism responsible for the rise of intracellular Ca(2+) concentration has remained elusive. Here, we describe the electrophysiological property associated with intracellular Ca(2+) signaling in frog parathyroid cells and show that Ca(2+)-activated Cl(-) channels are activated by intracellular Ca(2+) increase through an inositol 1,4,5-trisphophate (IP(3))-independent pathway. High extracellular Ca(2+) induced an outwardly-rectifying conductance in a dose-dependent manner (EC(50) ∼6 mM). The conductance was composed of an instantaneous time-independent component and a slowly activating time-dependent component and displayed a deactivating inward tail current. Extracellular Ca(2+)-induced and Ca(2+) dialysis-induced currents reversed at the equilibrium potential of Cl(-) and were inhibited by niflumic acid (a specific blocker of Ca(2+)-activated Cl(-) channel). Gramicidin-perforated whole-cell recording displayed the shift of the reversal potential in extracellular Ca(2+)-induced current, suggesting the change of intracellular Cl(-) concentration in a few minutes. Extracellular Ca(2+)-induced currents displayed a moderate dependency on guanosine triphosphate (GTP). All blockers for phospholipase C, diacylglycerol (DAG) lipase, monoacylglycerol (MAG) lipase and lipoxygenase inhibited extracellular Ca(2+)-induced current. IP(3) dialysis failed to induce conductance increase, but 2-arachidonoylglycerol (2-AG), arachidonic acid and 12S-hydroperoxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12(S)-HPETE) dialysis increased the conductance identical to extracellular Ca(2+)-induced conductance. These results indicate that high extracellular Ca(2+) raises intracellular Ca(2+) concentration through the DAG lipase/lipoxygenase pathway, resulting in the activation of Cl(-) conductance.

  9. The effects of TNF-alpha and inhibitors of arachidonic acid metabolism on human colon HT-29 cells depend on differentiation status.

    PubMed

    Kovaríková, Martina; Hofmanová, Jirina; Soucek, Karel; Kozubík, Alois

    2004-02-01

    The level of differentiation could influence sensitivity of colonic epithelial cells to various stimuli. In our study, the effects of TNF-alpha, inhibitors of arachidonic acid (AA) metabolism (baicalein, BA; indomethacin, INDO; niflumic acid, NA; nordihydroguaiaretic acid, NDGA), and/or their combinations on undifferentiated or sodium butyrate (NaBt)-differentiated human colon adenocarcinoma HT-29 cells were compared. NaBt-treated cells became growth arrested (blocked in G0/G1 phase of the cell cycle), and showed down-regulated Bcl-xL and up-regulated Bak proteins and increased expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). These cells were more perceptive to anti-proliferative and apoptotic effects of TNF-alpha. Both inhibitors of LOX (BA and NDGA) and COX (INDO and NA) in higher concentrations modulated cell cycle changes accompanying NaBt-induced differentiation and induced various level of cell death in undifferentiated and differentiated cells. Most important is our finding that TNF-alpha action on proliferation and cell death can be potentiated by co-treatment of cells with AA metabolism inhibitors, and that these effects were more significant in undifferentiated cells. TNF-alpha and INDO co-treatment was associated with accumulation of cells in G0/G1 cell cycle phase, increased reactive oxygen species production, and elevated caspase-3 activity. These results indicate the role of differentiation status in the sensitivity of HT-29 cells to the anti-proliferative and proapoptotic effects of TNF-alpha, AA metabolism inhibitors, and their combinations, and imply promising possibility for novel anti-cancer strategies.

  10. Consumption of Red Meat, but Not Cooking Oils High in Polyunsaturated Fat, Is Associated with Higher Arachidonic Acid Status in Singapore Chinese Adults.

    PubMed

    Seah, Jowy Yi Hoong; Gay, Gibson Ming Wei; Su, Jin; Tai, E-Shyong; Yuan, Jian-Min; Koh, Woon-Puay; Ong, Choon Nam; van Dam, Rob M

    2017-01-31

    High arachidonic acid (AA; 20:4 n - 6) status may have adverse effects on inflammation and risk of cardiovascular diseases. Concerns about high intake of n - 6 polyunsaturated fatty acids (PUFAs) are based on the premise that endogenous conversion from linoleic acid (LA; 18:2 n - 6) is an important source of AA, but few population-based studies have investigated dietary determinants of AA status. In this study, we examined habitual food consumption in relation to plasma concentrations of AA and other PUFAs in population-based studies. We used cross-sectional data from 269 healthy, ethnic Chinese participants (25-80 years old) with contrasting intakes of fish and red meat from the Singapore Prospective Study Program and 769 healthy participants (44-74 years old) from the Singapore Chinese Health Study as a validation set. Multivariable linear regression was used to examine PUFA intake (% energy) and food sources of PUFA (fish, red meat, poultry, soy and cooking oils) in relation to plasma PUFAs (AA, LA, dihomo-gamma-linolenic acid (DGLA; 20:3 n - 6), alpha-linolenic acid (ALA; 18:3 n - 3), eicosapentaenoic acid (EPA; 20:5 n - 3), and docosahexaenoic acid (DHA; 22:6 n - 3)) concentrations. Higher intake of red meat was associated with higher plasma AA concentrations. High intake of PUFA or PUFA-rich oils was associated with higher plasma ALA but not with plasma AA. Higher intakes of soy were associated with higher ALA and fish with higher DHA and EPA concentrations. These associations were statistically significant (p < 0.05) in both studies. Red meat consumption, but not PUFA or PUFA-rich cooking oil, was associated with circulating AA suggesting that intake of pre-formed AA rather than LA is an important determinant of AA status. A diet high in fish, soy products and polyunsaturated cooking oil, and low in red meat may be associated with an optimal plasma profile of PUFA in this Chinese population.

  11. Consumption of Red Meat, but Not Cooking Oils High in Polyunsaturated Fat, Is Associated with Higher Arachidonic Acid Status in Singapore Chinese Adults

    PubMed Central

    Seah, Jowy Yi Hoong; Gay, Gibson Ming Wei; Su, Jin; Tai, E-Shyong; Yuan, Jian-Min; Koh, Woon-Puay; Ong, Choon Nam; van Dam, Rob M.

    2017-01-01

    High arachidonic acid (AA; 20:4n-6) status may have adverse effects on inflammation and risk of cardiovascular diseases. Concerns about high intake of n-6 polyunsaturated fatty acids (PUFAs) are based on the premise that endogenous conversion from linoleic acid (LA; 18:2n-6) is an important source of AA, but few population-based studies have investigated dietary determinants of AA status. In this study, we examined habitual food consumption in relation to plasma concentrations of AA and other PUFAs in population-based studies. We used cross-sectional data from 269 healthy, ethnic Chinese participants (25–80 years old) with contrasting intakes of fish and red meat from the Singapore Prospective Study Program and 769 healthy participants (44–74 years old) from the Singapore Chinese Health Study as a validation set. Multivariable linear regression was used to examine PUFA intake (% energy) and food sources of PUFA (fish, red meat, poultry, soy and cooking oils) in relation to plasma PUFAs (AA, LA, dihomo-gamma-linolenic acid (DGLA; 20:3n-6), alpha-linolenic acid (ALA; 18:3n-3), eicosapentaenoic acid (EPA; 20:5n-3), and docosahexaenoic acid (DHA; 22:6n-3)) concentrations. Higher intake of red meat was associated with higher plasma AA concentrations. High intake of PUFA or PUFA-rich oils was associated with higher plasma ALA but not with plasma AA. Higher intakes of soy were associated with higher ALA and fish with higher DHA and EPA concentrations. These associations were statistically significant (p < 0.05) in both studies. Red meat consumption, but not PUFA or PUFA-rich cooking oil, was associated with circulating AA suggesting that intake of pre-formed AA rather than LA is an important determinant of AA status. A diet high in fish, soy products and polyunsaturated cooking oil, and low in red meat may be associated with an optimal plasma profile of PUFA in this Chinese population. PMID:28146136

  12. Arachidonic acid enhances TPA-induced differentiation in human leukemia HL-60 cells via reactive oxygen species-dependent ERK activation.

    PubMed

    Chien, Chih-Chiang; Wu, Ming-Shun; Shen, Shing-Chuan; Yang, Liang-Yo; Wu, Wen-Shin; Chen, Yen-Chou

    2013-04-01

    The phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), is a potent stimulator of differentiation in human leukemia cells; however, the effects of arachidonic acid (AA) on TPA-induced differentiation are still unclear. In the present study, we investigated the contribution of AA to TPA-induced differentiation of human leukemia HL-60 cells. We found that treatment of HL-60 cells with TPA resulted in increases in cell attachment and nitroblue tetrazolium (NBT)-positive cells, which were significantly enhanced by the addition of AA. Stimulation of TPA-induced intracellular reactive oxygen species (ROS) production by AA was detected in HL-60 cells via a DCHF-DA analysis, and the addition of the antioxidant, N-acetyl-cysteine (NAC), was able to reduce TPA+AA-induced differentiation in accordance with suppression of intracellular peroxide elevation by TPA+AA. Furthermore, activation of extracellular-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) by TPA+AA was identified in HL-60 cells, and the ERK inhibitor, PD98059, but not the JNK inhibitor, SP600125, inhibited TPA+AA-induced NBT-positive cells. Suppression of TPA+AA-induced ERK protein phosphorylation by PD98059 and NAC was detected, and AA enhanced ERK protein phosphorylation by TPA was in HL-60 cells. AA clearly increased TPA-induced HL-60 cell differentiation, as evidenced by a marked increase in CD11b expression, which was inhibited by NAC and PD98059 addition. Eicosapentaenoic acid (EPA) as well as AA showed increased intracellular peroxide production and differentiation of HL-60 cells elicited by TPA. Evidence of AA potentiation of differentiation by TPA in human leukemia cells HL-60 via activation of ROS-dependent ERK protein phosphorylation was first demonstrated herein.

  13. Promoting effect of arachidonic acid supplementation on N-methyl-N-nitrosourea-induced pancreatic acinar cell hyperplasia in young Lewis rats.

    PubMed

    Yoshizawa, Katsuhiko; Uehara, Norihisa; Kimura, Ayako; Emoto, Yuko; Kinoshita, Yuichi; Yuri, Takashi; Takada, Hideho; Moriguchi, Toru; Hamazaki, Tomohito; Tsubura, Airo

    2013-01-01

    Arachidonic acid (AA) is naturally found in human breast milk. AA, together with docosahexaenoic acid, is commonly added as a functional food ingredient to commercial infant formula worldwide, in accordance with the international standard of Codex Alimentarius. However, few studies have been performed that are concerned with the possible carcinogenic effects of AA supplementation during neonatal life. The effect of dietary AA supplementation in dams, during gestation and lactation, was investigated in N-methyl-N-nitrosourea (MNU)-induced preneoplastic lesions in the exocrine pancreas of young Lewis rats. Dams were fed either an AA (2.0% AA) or a basal (<0.01% AA) diet. On postnatal day 0 (at birth), male and female pups received a single intraperitoneal injection of either 35 mg/kg MNU or vehicle. The morphology and proliferating activity of the exocrine pancreas were examined by proliferative cell nuclear antigen immunohistochemistry 7, 14, 21, 28 and/or 60 days post-MNU. Histopathologically, acinar cell hyperplasia (ACH) occurred in the MNU-treated groups 60 days after MNU injection, irrespecitive of whether the rats had been fed an AA diet. Morphometrically, the number and area of ACH per 1 mm(2) in MNU-treated rats increased significantly in the AA diet-fed rats, compared with basal diet-fed rats. The number of proliferative cell nuclear antigen-positive acinar cells in both the normal and hyperplastic areas of MNU-treated rats increased significantly in the AA diet-fed rats. In conclusion, providing dams with an AA-rich diet during gestation and lactation promotes MNU-induced pancreatic ACH in young Lewis rats.

  14. ETHANOL AND ARACHIDONIC ACID SYNERGIZE TO ACTIVATE KUPFFER CELLS AND MODULATE THE FIBROGENIC RESPONSE VIA TNFα, GSH, AND TGFβ-DEPENDENT MECHANISMS

    PubMed Central

    2015-01-01

    Aim because of the contribution of ethanol and polyunsaturated fatty acids (PUFAs) to alcoholic liver disease, we investigated whether chronic ethanol administration and arachidonic acid (AA) could synergistically mediate Kupffer cell (KC) activation and modulate the stellate cell (HSC) fibrogenic response. Results 1) Ethanol and AA effects on KC and HSC mono-cultures: cell proliferation, lipid peroxidation, H2O2, O2.−, NADPH oxidase activity, and TNFα were higher in KCethanol than in KCcontrol, and were enhanced by AA; HSCethanol proliferated faster, increased collagen, and showed higher GSH than HSCcontrol, with modest effects by AA. 2) AA effects on the control co-culture: we previously reported (1) the ability of KC to induce a pro-fibrogenic response in HSC via ROS-dependent mechanisms; we now show that AA further increases cell proliferation and collagen in the control co-culture. The latter was prevented by vitamin E (an antioxidant) and by diphenyleneiodonium (a NADPH oxidase inhibitor). 3) Ethanol effects on the co-cultures: co-culture with KCcontrol or KCethanol induced HSCcontrol and HSCethanol proliferation; however, the pro-fibrogenic response in HSCethanol was suppressed due to up-regulation of TNFα and GSH, which was prevented by a TNFα neutralizing Ab and by l-buthionine-sulfoximine, a GSH-depleting agent. 4) Ethanol plus AA effects on the co-cultures: AA lowered TNFα in the HSCcontrol co-cultures allowing for enhanced collagen deposition; furthermore, AA restored the pro-fibrogenic response in the HSCethanol co-cultures by counteracting the up-regulation of TNFα and GSH with a significant increase in GSSG and in pro-fibrogenic TGFβ. Conclusion these results unveil synergism between ethanol and AA to the mechanism whereby KC mediate ECM remodeling, and suggest that even if chronic ethanol consumption sensitizes HSC to up-regulate anti-fibrogenic signals, their effects are blunted by a second ‘hit’ such as AA. PMID:19003881

  15. Modulation of the Expression of Components of the Stress Response by Dietary Arachidonic Acid in European Sea Bass (Dicentrarchus labrax) Larvae.

    PubMed

    Montero, Daniel; Terova, Genciana; Rimoldi, Simona; Betancor, Mónica B; Atalah, Eyad; Torrecillas, Silvia; Caballero, María J; Zamorano, María J; Izquierdo, Marisol

    2015-10-01

    This study reports for the first time on European sea bass, Dicentrarchus labrax (L.), larvae, the effect of different levels of dietary arachidonic acid (ARA; 20:4n-6) on the expression of genes related to the fish stress response. Copies of mRNA from genes related to steroidogenesis [StAR (steroidogenic acute regulatory protein), c-Fos, and CYP11β (11β-hydroxylase gene)], glucocorticoid receptor complex [GR (glucocorticoid receptor) and HSP (heat shock proteins) 70 and 90) and antioxidative stress (catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase] were quantified. Eighteen day-old larvae were fed for 14 days with three experimental diets with increasing levels of ARA (0.3, 0.6 and 1.2% d.w.) and similar levels of docosahexaenoic (22:6n-3) and eicosapentaenoic (20:5n-3) acids (5 and 3%, respectively). The quantification of stress-related genes transcripts was conducted by One-Step TaqMan real time RT-PCR with the standard curve method (absolute quantification). Increase dietary levels of ARA induced a significantly (p < 0.05) down-regulation of genes related to cortisol synthesis, such as StAR and CYP11β and up-regulated genes related to glucocorticoid receptor complex, such as HSP70 and GR. No effects were observed on antioxidant enzymes gene expression. These results revealed the regulatory role of dietary ARA on the expression of stress-related genes in European sea bass larvae.

  16. Safflower and olive oil dietary treatments rescue aberrant embryonic arachidonic acid and nitric oxide metabolism and prevent diabetic embryopathy in rats.

    PubMed

    Higa, R; White, V; Martínez, N; Kurtz, M; Capobianco, E; Jawerbaum, A

    2010-04-01

    Aberrant arachidonic acid and nitric oxide (NO) metabolic pathways are involved in diabetic embryopathy. Previous works have found diminished concentrations of PGE(2) and PGI(2) in embryos from diabetic rats, and that PGI(2) is capable of increasing embryonic PGE(2) concentrations through the activation of the nuclear receptor PPARdelta. PPARdelta activators are lipid molecules such as oleic and linoleic acids, present in high concentrations in olive and safflower oils, respectively. The aim of this study was to analyze the capability of dietary supplementation with either 6% olive or 6% safflower oils to regulate PGE(2), PGI(2) and NO concentrations in embryos and deciduas from control and diabetic rats during early organogenesis. Diabetes was induced by a single injection of streptozotocin (55 mg/kg) 1 week before mating. Animals were fed with the oil-supplemented diets from Days 0.5 to 10.5 of gestation. PGI(2) and PGE(2) were measured by EIA and NO through the evaluation of its stable metabolites nitrates-nitrites in 10.5 day embryos and deciduas. We found that the olive and safflower oil-supplemented treatments highly reduced resorption and malformation rates in diabetic animals, and that they were able to prevent maternal diabetes-induced alterations in embryonic and decidual PGI(2) and PGE(2) concentrations. Moreover, these dietary treatments prevented NO overproduction in embryos and deciduas from diabetic rats. These data indicate that in maternal diabetes both the embryo and the decidua benefit from the olive and safflower oil supplementation probably through mechanisms that involve the rescue of aberrant prostaglandin and NO generation and that prevent developmental damage during early organogenesis.

  17. Quantification of Arachidonic Acid and Its Metabolites in Rat Tissues by UHPLC-MS/MS: Application for the Identification of Potential Biomarkers of Benign Prostatic Hyperplasia

    PubMed Central

    Bian, Qiaoxia; Wang, Weihui; Wang, Nannan; Peng, Yan; Ma, Wen; Dai, Ronghua

    2016-01-01

    To evaluate the potential relationship between benign prostatic hyperplasia (BPH) and the arachidonic acid (AA) metabolome, a UHPLC—MS/MS method has been developed and validated for simultaneous determination of AA and its cyclooxygenase(COX) and lipoxygenase(LOX) pathway metabolites (15-HETE, 12-HETE, TXA2, 5-HETE, AA, PGI2, PGF2α, 8-HETE, PGD2, PGE2 and LTB4) in rat tissues. The analytes were extracted from tissue samples with a protein precipitation procedure and then separated on a Shim-pack XR-ODSC18 column with 0.05% formic acid in water (pH adjusted with dilute ammonia) and methanol:acetonitrile (20:80, v/v). Detection was performed on a UHPLC—MS/MS system with electrospray negative ionization (ESI) and a multiple reaction-monitoring mode. The lower limits of quantification (LLOQ) were 0.25–50 ng/mL for all of the analytes in the prostate, seminal, bladder, liver and kidney tissues. The absolute recoveries of the analytes from all of the tissues were more than 50%. By means of the method developed, the AA metabolites in tissue samples from Sham and BPH group rats were determined. The eleven biomarkers in the BPH group prostate, seminal, bladder, liver and kidney tissues were significantly higher than those of the sham group, indicating that BPH fortified the inducible expression of COX and LOX, as well as increased the production of AA and eicosanoids. The method described here offers a useful tool for the evaluation of complex regulatory eicosanoids responses in vivo. PMID:27893755

  18. Arachidonic acid-containing phosphatidylcholine characterized by consolidated plasma and liver lipidomics as an early onset marker for tamoxifen-induced hepatic phospholipidosis.

    PubMed

    Saito, Kosuke; Goda, Keisuke; Kobayashi, Akio; Yamada, Naohito; Maekawa, Kyoko; Saito, Yoshiro; Sugai, Shoichiro

    2017-01-31

    Lipid profiling has emerged as an effective approach to not only screen disease and drug toxicity biomarkers but also understand their underlying mechanisms of action. Tamoxifen, a widely used antiestrogenic agent for adjuvant therapy against estrogen-positive breast cancer, possesses side effects such as hepatic steatosis and phospholipidosis (PLD). In the present study, we administered tamoxifen to Sprague-Dawley rats and used lipidomics to reveal tamoxifen-induced alteration of the hepatic lipid profile and its association with the plasma lipid profile. Treatment with tamoxifen for 28 days caused hepatic PLD in rats. We compared the plasma and liver lipid profiles in treated vs. untreated rats using a multivariate analysis to determine differences between the two groups. In total, 25 plasma and 45 liver lipids were identified and altered in the tamoxifen-treated group. Of these lipids, arachidonic acid (AA)-containing phosphatidylcholines (PCs), such as PC (17:0/20:4) and PC (18:1/20:4), were commonly reduced in both plasma and liver. Conversely, tamoxifen increased other phosphoglycerolipids in the liver, such as phosphatidylethanolamine (18:1/18:1) and phosphatidylinositol (18:0/18:2). We also examined alteration of AA-containing PCs and some phosphoglycerolipids in the pre-PLD stage and found that these lipid alterations were initiated before pathological alteration in the liver. In addition, changes in plasma and liver levels of AA-containing PCs were linearly associated. Moreover, levels of free AA and mRNA levels of AA-synthesizing enzymes, such as fatty acid desaturase 1 and 2, were decreased by tamoxifen treatment. Therefore, our study demonstrated that AA-containing PCs might have potential utility as novel and predictive biomarkers for tamoxifen-induced PLD. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Effects of arachidonic acid supplementation in maturation diet on female reproductive performance and larval quality of giant river prawn (Macrobrachium rosenbergii)

    PubMed Central

    Pratoomyot, Jarunan; Siranonthana, Nisa; Senanan, Wansuk

    2016-01-01

    The giant river prawn (Macrobrachium rosenbergii) is one of the most farmed freshwater crustaceans in the world. Its global production has been stalling in the past decade due to the inconsistent quality of broodstock and hatchery-produced seeds. A better understanding of the role of nutrition in maturation diets will help overcome some of the production challenges. Arachidonic acid (20:4 n-6, ARA) is a fatty acid precursor of signaling molecules important for crustacean reproduction, prostaglandins E and F of the series II (PGE2 and PGF2α), and is often lacking in maturation diets of shrimp and prawns. We examined the effects of ARA in a combination of different fish oil (FO) and soybean oil (SO) blends on females’ reproductive performance and larval quality. Adult females (15.22 ± 0.13 g and 11.12 ± 0.09 cm) were fed six isonitrogenous and isolipidic diets containing one of two different base compositions (A or B), supplemented with one of three levels of Mortierella alpine-derived ARA (containing 40% active ARA): 0, 1 or 2% by ingredient weight. The two base diets differed in the percentages of (FO and SO with diet A containing 2% SO and 2% FO and diet B containing 2.5% SO and 1.5% FO, resulting in differences in proportional contents of dietary linoleic acid (18:2n-6, LOA) and docosahexaenoic acid (22:6n-3, DHA)). After the eight-week experiment, prawns fed diet B with 1 and 2% ARA supplement (B1 and B2) exhibited the highest gonadosomatic index (GSI), hepatosomatic index (HSI), egg clutch weight, fecundity, hatching rate, number of larvae, and reproductive effort compared to those fed other diets (p ≤ 0.05). Larvae from these two dietary treatments also had higher tolerance to low salinity (2 ppt). The maturation period was not significantly different among most treatments (p ≥ 0.05). ARA supplementation, regardless of the base diet, significantly improved GSI, HSI, egg clutch weight and fecundity. However, the diets with an enhanced ARA and LOA

  20. The aflatoxin B1 -fumonisin B1 toxicity in BRL-3A hepatocytes is associated to induction of cytochrome P450 activity and arachidonic acid metabolism.

    PubMed

    Mary, Verónica S; Arias, Silvina L; Otaiza, Santiago N; Velez, Pilar A; Rubinstein, Héctor R; Theumer, Martín G

    2017-02-09

    Human oral exposure to aflatoxin B1 (AFB1 ) and fumonisin B1 (FB1 ) is associated with increased hepatocellular carcinoma. Although evidence suggested interactive AFB1 -FB1 hepatotoxicity, the underlying mechanisms remain mostly unidentified. This work was aimed at evaluating the possible AFB1 -FB1 interplay to induce genetic and cell cycle toxicities in BRL-3A rat hepatocytes, reactive oxygen species (ROS) involvement, and the AFB1 metabolizing pathways cytochrome P450 (CYP) and arachidonic acid (ArAc) metabolism as ROS contributors. Flow cytometry of stained BRL-3A hepatocytes was used to study the cell cycle (propidium iodide), ROS intracellular production (DCFH-DA, HE, DAF-2 DA), and phospholipase A activity (staining with bis-BODIPY FL C11-PC). The CYP1A activity was assessed by the 7-ethoxyresorufin-O-deethylase (EROD) assay. Despite a 48-h exposure to FB1 (30 μM) not being genotoxic, the AFB1 (20 μM)-induced micronucleus frequency was overcome by the AFB1 -FB1 mixture (MIX), presumably showing toxin interaction. The mycotoxins blocked G1/S-phase, but only MIX caused cell death. Overall, the oxidative stress led these alterations as the pretreatment with N-acetyl-l-cysteine reduced such toxic effects. While AFB1 had a major input to the MIX pro-oxidant activity, with CYP and ArAc metabolism being ROS contributors, these pathways were not involved in the FB1 -elicited weak oxidative stress. The MIX-induced micronucleus frequency in N-acetyl-l-cysteine pretreated cells was greater than that caused by AFB1 without antioxidants, suggesting enhanced AFB1 direct genotoxicity probably owing to the higher CYP activity and ArAc metabolism found in MIX. The metabolic pathways modulation by AFB1 -FB1 mixtures could raise its hepatocarcinogenic properties.

  1. Altered arachidonic acid metabolism via COX-1 and COX-2 contributes to the endothelial dysfunction of penile arteries from obese Zucker rats

    PubMed Central

    Sánchez, A; Contreras, C; Villalba, N; Martínez, P; Martínez, AC; Bríones, A; Salaíces, M; García-Sacristán, A; Hernández, M; Prieto, D

    2010-01-01

    Background and purpose: The aim of the current study was to investigate the role of arachidonic acid (AA) metabolism via cyclooxygenase (COX) in the endothelial dysfunction of penile arteries from pre-diabetic, obese Zucker rats (OZR). Experimental approach: Penile arteries from OZR and from lean Zucker rats (LZR) were mounted in microvascular myographs to assess vascular function and COX expression was determined by immunohistochemistry. Key results: Acetylcholine (ACh) and AA elicited relaxations that were impaired in arteries from OZR. Inhibition of both COX-1 and COX-2 reduced the relaxant effects of ACh and AA in LZR but not in OZR. Inhibitors of COX-1 and of the TXA2/PGH2 (TP) receptor enhanced the relaxations induced by AA in both LZR and OZR, whereas COX-2 inhibition enhanced these responses only in OZR. TP receptor blockade did not restore ACh relaxant responses in arteries from OZR. Inhibition of COX-1 increased basal tension in OZR and this contraction was blunted by TP receptor blockade. The vasoconstrictor responses to noradrenaline were augmented by indomethacin and by COX-2 inhibition in LZR but not in OZR. Immunohistochemical staining showed that both COX-1 and COX-2 are expressed in the endothelium of penile arteries from both LZR and OZR. Conclusions and implications: Vasoactive prostanoids were formed via constitutively active COX-1 and COX-2 pathways in normal rat penile arteries. Under conditions of insulin resistance, the release and/or effects of vasodilator prostanoids were impaired, contributing to the blunted endothelium-dependent vasodilatation and to the enhanced vasoconstriction. PMID:20082610

  2. Exogenous addition of arachidonic acid to the culture media enhances the functionality of dendritic cells for their possible use in cancer immunotherapy.

    PubMed

    Kumar, Jeetendra; Gurav, Rupali; Kale, Vaijayanti; Limaye, Lalita

    2014-01-01

    The development of dendritic cell based vaccines is a promising approach in cancer immunotherapy. For their successful use in the clinics, the propagation and functionality of DCs is crucial. We earlier established a two-step method for the large scale generation of DCs from umbilical cord blood derived MNCs/CD34(+) cells. This work aims at improving their functionality based on the following observations: in vitro generated DCs can be less efficient in migration and other functional activities due to lower eicosanoid levels. The production of eicosanoids from Arachidonic Acid (AA) can be hampered due to suppression of the enzyme phospholipase A2 by IL-4, an essential cytokine required for the differentiation of DCs. We hypothesized that exogenous addition of AA to the culture media during DC generation may result in DCs with improved functionality. DCs were generated with and without AA. The two DC sets were compared by phenotypic analysis, morphology and functional assays like antigen uptake, MLR, CTL assay and in vitro and in vivo migration. Though there were no differences between the two types of DCs in terms of morphology, phenotype and antigen uptake, AA(+) DCs exhibited an enhanced in vitro and in vivo migration, T cell stimulatory capacity, CTL activity and significantly higher transcript levels of COX-2. AA(+) DCs also show a favorable Th1 cytokine profile than AA- DCs. Thus addition of AA to the culture media is skewing the DCs towards the secretion of more IL-12 and less of IL-10 along with the restoration of eicosanoids levels in a COX-2 mediated pathway thereby enhancing the functionality of these cells to be used as a potent cellular vaccine. Taken together, these findings will be helpful in the better contriving of DC based vaccines for cancer immunotherapy.

  3. High dietary arachidonic acid levels affect the process of eye migration and head shape in pseudoalbino Senegalese sole Solea senegalensis early juveniles.

    PubMed

    Boglino, A; Wishkerman, A; Darias, M J; Andree, K B; de la Iglesia, P; Estévez, A; Gisbert, E

    2013-11-01

    The effect of high dietary levels of arachidonic acid (ARA) on the eye migration and cranial bone remodelling processes in Senegalese sole Solea senegalensis early juveniles (age: 50 days post hatch) was evaluated by means of geometric morphometric analysis and alizarin red staining of cranial skeletal elements. The incidence of normally pigmented fish fed the control diet was 99·1 ± 0·3% (mean ± s.e.), whereas it was only 18·7 ± 7·5% for those fed high levels of ARA (ARA-H). The frequency of cranial deformities was significantly higher in fish fed ARA-H (95·1 ± 1·5%) than in those fed the control diet (1·9 ± 1·9%). Cranial deformities were significantly and negatively correlated with the incidence of normally pigmented animals (r² = -0·88, P < 0·001, n = 16). Thus, fish displaying pigmentary disorders differed in the position of their eyes with regard to the vertebral column and mouth axes, and by the interocular distance and head height, which were shorter than in fish not displaying pigmentary disorders. In addition to changes in the positioning of both eyes, pseudoalbino fish showed some ARA-induced osteological differences for some of the skeletal elements from the splanchnocranium (e.g. right premaxillary, dentary, angular, lacrimal, ceratohyal and branchiostegal rays) and neurocranium (e.g. sphenotic, left lateral ethmoid and left frontal) by comparison to normally pigmented specimens. Pseudoalbino fish also had teeth in both lower and upper jaws. This is the first study in Pleuronectiformes that describes impaired metamorphic relocation of the ocular side eye, the right eye in the case of S. senegalensis, whereas the left eye migrated into the ocular side almost normally.

  4. Levels of prostaglandin E metabolite and leukotriene E(4) are increased in the urine of smokers: evidence that celecoxib shunts arachidonic acid into the 5-lipoxygenase pathway.

    PubMed

    Duffield-Lillico, Anna J; Boyle, Jay O; Zhou, Xi Kathy; Ghosh, Aradhana; Butala, Geera S; Subbaramaiah, Kotha; Newman, Robert A; Morrow, Jason D; Milne, Ginger L; Dannenberg, Andrew J

    2009-04-01

    Cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) play a role in inflammation and carcinogenesis. Biomarkers that reflect tobacco smoke-induced tissue injury are needed. In this study, levels of urinary prostaglandin E metabolite (PGE-M) and leukotriene E(4) (LTE(4)), biomarkers of the COX and 5-LO pathways, were compared in never smokers, former smokers, and current smokers. The effects of celecoxib, a selective COX-2 inhibitor, on levels of PGE-M and LTE(4) were determined. Baseline levels of PGE-M and LTE(4) were positively associated with smoking status; levels of PGE-M and LTE(4) were higher in current versus never smokers. Treatment with 200 mg celecoxib twice daily for 6 +/- 1 days led to a reduction in urinary PGE-M levels in all groups but exhibited the greatest effect among subjects with high baseline PGE-M levels. Thus, high baseline PGE-M levels in smokers reflected increased COX-2 activity. In individuals with high baseline PGE-M levels, treatment with celecoxib led to a significant increase in levels of urinary LTE(4), an effect that was not found in individuals with low baseline PGE-M levels. In conclusion, increased levels of urinary PGE-M and LTE(4) were found in human smokers, a result that may reflect subclinical lung inflammation. In individuals with high baseline levels of PGE-M (elevated COX-2 activity), celecoxib administration shunted arachidonic acid into the proinflammatory 5-LO pathway. Because 5-LO activity and LTE(4) have been suggested to play a role in cardiovascular disease, these results may help to explain the link between use of COX-2 inhibitors and cardiovascular complications.

  5. Potential Dengue Virus-Triggered Apoptotic Pathway in Human Neuroblastoma Cells: Arachidonic Acid, Superoxide Anion, and NF-κB Are Sequentially Involved

    PubMed Central

    Jan, Jia-Tsrong; Chen, Bor-Horng; Ma, Shiou-Hwa; Liu, Chiu-I; Tsai, Hui-Ping; Wu, Han-Chung; Jiang, Shian-Yuan; Yang, Kuen-Der; Shaio, Men-Fang

    2000-01-01

    Direct in vivo evidence for the susceptibility of human neuronal cells to dengue virus has not been reported. In this study, we demonstrated that type 2 dengue (DEN-2) virus infection induced extensive apoptosis in the human neuroblastoma cell line SK-N-SH. Phospholipase A2 (PLA2) was activated by DEN-2 infection, which led to the generation of arachidonic acid (AA). Inhibition of PLA2 activity by the PLA2 inhibitors, AACOCF3 and ONO-RS-082, diminished DEN-2 virus-induced apoptosis. In contrast, the cyclooxygenase inhibitors aspirin and indomethacin, thought to increase AA accumulation by blocking AA catabolism, enhanced apoptosis. Exogenous AA induced apoptosis in a dose-dependent manner. Superoxide anion, which is thought to be generated through the AA-activated NADPH oxidase, was increased after infection. Pretreatment with superoxide dismutase (SOD) protected cells against DEN-2 virus-induced apoptosis. Furthermore, generation of superoxide anion was blocked by AACOCF3. In addition, the transcription factors, NF-κB and c-Jun, were found to be activated after DEN-2 virus infection. However, pretreatment of cells with oligodeoxynucleotides containing NF-κB, but not c-Jun, binding sites (transcription factor decoy) strongly prevented dengue virus-induced apoptosis. The finding that AACOCF3 and SOD significantly block activation of NF-κB suggests that this activation is derived from the AA-superoxide anion pathway. Our results indicate that DEN-2 virus infection of human neuroblastoma cells triggers an apoptotic pathway through PLA2 activation to superoxide anion generation and subsequently to NF-κB activation. This apoptotic effect can be either directly derived from the action of AA and superoxide anion on mitochondria or indirectly derived from the products of apoptosis-related genes activated by NF-κB. PMID:10954569

  6. In vivo imaging of disturbed pre- and post-synaptic dopaminergic signaling via arachidonic acid in a rat model of Parkinson’s disease

    PubMed Central

    Bhattacharjee, Abesh Kumar; Meister, Lindsey M.; Chang, Lisa; Bazinet, Richard P.; White, Laura; Rapoport, Stanley I.

    2007-01-01

    Parkinson’s disease involves loss of dopamine (DA)-producing neurons in the substantia nigra, associated with fewer pre-synaptic DA transporters (DATs) but more post-synaptic dopaminergic D2 receptors in terminal areas of these neurons. Hypothesis Arachidonic acid (AA) signaling via post-synaptic D2 receptors coupled to cytosolic phospholipase A2 (cPLA2) will be reduced in terminal areas ipsilateral to a chronic unilateral substantia nigra lesion in rats given D-amphetamine, which reverses the direction of the DAT, but will be increased in rats given quinpirole, a D2-receptor agonist. Methods D-amphetamine (5.0 mg/kg i.p.), quinpirole (1.0 mg/kg i.v.), or saline was administered to unanesthetized rats having a chronic unilateral lesion of the substantia nigra. AA incorporation coefficients, k* (radioactivity/integrated plasma radioactivity), markers of AA signaling, were measured using quantitative autoradiography in 62 bilateral brain regions following intravenous [1-14C]AA. Results In rats given saline (baseline), k* was elevated in 13 regions in the lesioned compared with intact hemisphere. Quinpirole increased k* in frontal cortical and basal ganglia regions bilaterally, more so in the lesioned than intact hemisphere. D-amphetamine increased k* bilaterally but less so in the lesioned hemisphere. Conclusions Increased baseline elevations of k* and increased responsiveness to quinpirole in the lesioned hemisphere are consistent with their higher D2-receptor and cPLA2 activity levels, whereas reduced responsiveness to D-amphetamine is consistent with dropout of pre-synaptic elements containing the DAT. In vivo imaging of AA signaling using dopaminergic drugs can identify pre- and post-synaptic DA changes in animal models of Parkinson’s disease. PMID:17681816

  7. Cytochrome P450 metabolites of arachidonic acid are potent inhibitors of vasopressin action on rabbit cortical collecting duct.

    PubMed Central

    Hirt, D L; Capdevila, J; Falck, J R; Breyer, M D; Jacobson, H R

    1989-01-01

    AA is metabolized by a cytochrome P450, NADPH-dependent epoxygenase to four regioisomeric epoxyeicosatrienoic acids (EETs). The EETs are further hydrated enzymatically to their respective diols, vic-dihydroxyeicosatrienoic acids (DHETs). We studied the effect of pretreatment with DHETs on 10 microU/cm2 arginine vasopressin (AVP)-stimulated hydraulic conductivity (Lp) (Lp x 10(-7) cm/atm/s, mean +/- SE) in rabbit cortical collecting ducts (CCDs) perfused in vitro at 37 degrees C. At 10(-6) M all four DHETs were potent inhibitors of the hydroosmotic effect of AVP. 14,15-DHET was the most potent isomer; it reduced AVP-induced Lp from a control value of 234.75 +/- 11.7, n = 17, to a value of 95.2 +/- 8.39, n = 5, P less than 0.0001, a reduction of AVP-mediated water flow of 60%. The inhibitory effect of 14,15-DHET was dose dependent and significant to nanomolar concentrations. 14,15-DHET at 10(-7) M was as potent an inhibitor of AVP's activity as was 10(-7) M PGE2. AVP's hydroosmotic effect is mediated through its intracellular second messenger, cAMP. 8-p-Chlorophenylthio-cAMP (CcAMP) at 10(-4) M induced a peak Lp of 189.6 +/- 11.0, n = 8; pretreatment with 10(-6) M 14,15-DHET reduced CcAMP-peak Lp to 132.0 +/- 13.4, n = 5, P less than 0.01, demonstrating a post-cAMP effect. Gas chromatography/mass spectroscopy suggests that EETs are present in extracts purified from CCDs. We conclude that cytochrome P450 epoxygenase eicosanoids are potent inhibitors of the hydroosmotic effect of vasopressin and are endogenous constituents of normal CCDs, the major target tissue for AVP. Images PMID:2556446

  8. Molecular cloning and functional characterization of arachidonate 5-lipoxygenase (Alox5), and its expression in response to the ratio of linolenic acid to linoleic acid in diets of large yellow croaker (Larmichthys crocea).

    PubMed

    Wang, Tianjiao; Zuo, Rantao; Mai, Kangsen; Xu, Wei; Ai, Qinghui

    2016-11-01

    This study was conducted to clone and functionally characterize a full-length cDNA encoding arachidonate 5-lipoxygenase (Alox5) from large yellow croaker (Larmichthys crocea) and investigate its gene expression in response to graded dietary ratio of linolenic acid (ALA) to linoleic acid (LNA) (0.03, 0.06, 0.45, 0.90 and 1.51). An isolated 2372bp cDNA clone of Alox5 contained an open reading frame spanning 2025bp encoding a protein with the ability to modify arachidonate acid (AA) to 5-hydroxyeicosatetraenoic (5-HETE). In the liver, the Alox5 mRNA expression levels significantly increased to the maximum when the dietary ALA/LNA increased from 0.03 to 0.06, and then significantly decreased with dietary ALA/LNA increased to 1.51 (P<0.05). In the kidney, the expression levels of Alox5 of fish fed diets with low dietary ALA/LNA (0.03-0.06) were significantly higher than those of fish fed diets with high dietary ALA/LNA (0.45-1.51) (P<0.05). The dual-luciferase reporter assays showed that the nuclear factor kappa B (NF-κB) could act on cognate cis-acting elements in the promoter of Alox5 and increased the transcription of Alox5. Results of the present study suggested that the expression of Alox5 is higher in croakers fed high concentrations of LNA compared to those fed high concentrations of ALA, which might be regulated by NF-κB and contribute to the inflammation process by catalyzing the dioxygenation of AA.

  9. Risk factors for post-transplant diabetes mellitus in renal transplant: Role of genetic variability in the CYP450-mediated arachidonic acid metabolism.

    PubMed

    Gervasini, Guillermo; Luna, Enrique; García-Cerrada, Montserrat; García-Pino, Guadalupe; Cubero, Juan José

    2016-01-05

    Arachidonic acid (AA) is metabolized by cytochrome P450 (CYP) enzymes to epoxyeicosatrienoic acids (EETs) and 20-hidroxyeicosatetraenoic acid (20-HETE), which play an important role both in renal transplant and diabetes mellitus (DM). We searched for associations between polymorphisms in this metabolic pathway and the risk of post-transplant diabetes mellitus (PTDM) in kidney recipients. One-hundred-sixty-four patients were genotyped for common SNPs in this route, namely CYP2C8*3, CYP2C8*4, CYP2C9*2, CYP2C9*3, CYP2J2*7, CYP4A11 F434S and CYP4F2 V433M. Demographic and clinical parameters were retrospectively collected at four time-points in the first year after grafting. Thirty-four patients (20.73%) developed PTDM, which was more prevalent among older patients [OR for older age = 1.06 (1.03-1.10), p < 0.001] and in those with higher body mass index (BMI) [OR for higher average BMI in the first year = 1.13 (1.04-1.23); p < 0.01]. Creatinine clearance [OR = 0.97 (0.95-0.99); p < 0.01] and exposure to tacrolimus [OR = 3.25 (1.15-9.19); p < 0.05] were also relevant for PTDM risk. With regard to genetic variants, logistic regression analysis controlling for significant demographic and clinical variables showed that the V433M polymorphism in CYP4F2, responsible for 20-HETE synthesis, was an independent risk factor for PTDM [OR = 3.94 (1.08-14.33); p < 0.05]. We have shown that a genetic variant in the CYP4F2 gene, the main gene implicated in 20-HETE synthesis, is associated with the risk for PTDM. Our findings suggest that genes in the metabolic pathways of AA may become good candidates in genetic association studies for PTDM.

  10. Differential release of mediators from human basophils: Differences in arachidonic acid metabolism following activation by unrelated stimuli

    SciTech Connect

    Warner, J.A.; Peters, S.P.; Lichtenstein, L.M.; Hubbard, W.; Yancey, K.B.; Stevenson, H.C.; Miller, P.J.; MacGlashan, D.W. Jr.

    1989-06-01

    We have examined the release of histamine and LTC4 from purified human basophils challenged with several different stimuli, both physiological and nonphysiological. Basophils (n = 16) challenged with 0.1 micrograms/ml anti-IgE released 38 +/- 4% of their available histamine and 39 +/- 12 ng LTC4/10(6) basophils within 15-30 min. F-Met peptide (n = 8) caused the release of 54 +/- 8% histamine and 42 +/- 25 ng LTC4/10(6) basophils within a period of 2-5 min. C5a caused the release of 22 +/- 3% histamine from selected donors but failed to initiate any LTC4 release unless combined with D2O or 5 mM extracellular calcium. The two nonphysiological stimuli A23187 and TPA caused extensive histamine release, 67 +/- 8 and 82 +/- 11%, respectively, and while A23187 initiated a large and rapid release of leukotriene, TPA failed to release any LTC4 even when combined with D2O or 2-5 mM extracellular calcium. Increased concentrations of extracellular calcium enhanced anti-IgE and f-Met peptide induced release of LTC4 but inhibited the A23187 induced release of leukotriene. A single peak of immunoreactive leukotriene C4 that comigrated with the authentic standard was identified using HPLC followed by radioimmunoassay. No LTD4 or LTE4 could be detected. Purified human basophils incubated with 0.2 microM (3H)AA incorporated 290 pmol/10(6) cells, or 32 +/- 5% of the available label within 60 min. The (3H)AA was taken principally into the phospholipids (73 +/- 5%), with 20 +/- 3% as neutral lipid, and only 5 +/- 2% remaining as the free acid. Three phospholipid subclasses, phosphatidylcholine, PC (24 +/- 2%), phosphatidylinositol, PI (22 +/- 1%), and phosphatidylethanolamine, PE (15 +/- 3%), accounted for the majority of the incorporated (3H)AA while the remainder of the phospholipids accounted for less than 5% of the total cpm.

  11. Nitric oxide donors prevent while the nitric oxide synthase inhibitor L-NAME increases arachidonic acid plus CYP2E1-dependent toxicity

    SciTech Connect

    Wu Defeng; Cederbaum, Arthur . E-mail: arthur.cederbaum@mssm.edu

    2006-10-15

    Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N {sup G}-Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48 {+-} 6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23 {+-} 5%, while, SNAP or DETA-NONO increased viability to 66 {+-} 8 or 71 {+-} 6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA

  12. Role of arachidonic acid and protein kinase C during maturation-inducing hormone-dependent meiotic resumption and ovulation in ovarian follicles of Atlantic croaker

    USGS Publications Warehouse

    Patino, R.; Yoshizaki, G.; Bolamba, D.; Thomas, P.

    2003-01-01

    The roles of arachidonic acid (AA) and protein kinase C (PKC) during in vitro maturation-inducing hormone (MIH)-dependent meiotic resumption (maturation) and ovulation were studied in ovarian follicles of Atlantic croaker (Micropogonias undulatus). The requirement for cyclooxygenase (COX) metabolites of AA was examined using a nonspecific COX inhibitor, indomethacin (IM), as well as two COX products, prostaglandin (PG) F2?? and PGE2, whereas the role of lipoxygenase (LOX) was investigated using a specific LOX inhibitor, nordihydroguaiaretic acid (NDGA). The involvement of PKC was examined using phorbol 12-myristate 13-acetate (PMA), a PKC activator, as well as GF109203X (GF), a specific inhibitor of PKC and 1-(5-isoquin- olinesulfonyl)-2-methylpiperazine (H7), nonspecific inhibitor of protein kinases. Genomic mechanisms were examined with the transcription-inhibitor actinomycin D (ActD) and the functionality of heterologous (oocyte-granulosa) gap junctions (GJ) with a dye transfer assay. The AA (100 ??M) and PGF2?? (5 ??M) did not induce maturation, and NDGA (10 ??M) did not affect MIH-dependent maturation. However, IM (100 ??M) partially inhibited MIH-dependent maturation. Conversely, AA and both PGs induced, and IM and NDGA inhibited, MIH-dependent ovulation in matured follicles. The PMA (1 ??g/ml) did not induce maturation but caused ovulation in matured follicles, whereas PKC inhibitors (GF, 5 ??M; H7, 50??M) did not affect MIH-dependent maturation but inhibited MIH- and PMA-dependent ovulation. The PMA-dependent ovulation was inhibited by IM but not by NDGA. In addition, ActD (5 ??M) blocked MIH-dependent, but not PMA-dependent, ovulation, and PGF2?? restored MIH-dependent ovulation in ActD-blocked follicles. The AA and PGs did not induce, and GF did not inhibit, MIH-dependent heterologous GJ uncoupling. In conclusion, AA and PKC mediate MIH-dependent ovulation but not meiotic resumption or heterologous GJ uncoupling in croaker follicles, but a permissive role

  13. ROLE OF INTRACELLULAR CALCIUM AND PHOSPHOLIPASE A2 IN ARACHIDONIC ACID-INDUCED TOXICITY IN LIVER CELLS OVEREXPRESSING CYP2E1*

    PubMed Central

    Caro, Andres A.; Cederbaum, Arthur I.

    2007-01-01

    Liver cells (HepG2 and primary hepatocytes) overexpressing CYP2E1 and exposed to arachidonic acid (AA) were previously shown to lose viability together with enhanced lipid peroxidation. These events were blocked in cells pre-incubated with antioxidants (α -tocopherol, glutathione ethyl ester), or in HepG2 cells not expressing CYP2E1. The goal of the current study was to evaluate the role of calcium and calcium-activated hydrolases in these CYP2E1-AA interactions. CYP2E1-expressing HepG2 cells treated with AA showed an early increase in cytosolic calcium and partial depletion of ionomycin-sensitive calcium stores. These changes in calcium were blocked by α -tocopherol. AA activated phospholipase A2 (PLA2) in CYP2E1-expressing liver cells, and this was inhibited by PLA2 inhibitors or α -tocopherol. PLA2 inhibitors prevented the cell death caused by AA, without affecting CYP2E1 activity or lipid peroxidation. AA toxicity and PLA2 activation were inhibited in calcium-depleted cells, but not by removal of extracellular calcium alone. Removal of extracellular calcium inhibited the early increase in cytosolic calcium caused by AA. CYP2E1 overexpressing HepG2 cells exposed to AA showed a decrease in mitochondrial membrane potential, which was prevented by the PLA2 inhibitors. These results suggest that AA-induced toxicity to CYPE1-expressing cells: (i) is associated with release of Ca2+ from intracellular stores that depends mainly on oxidative membrane damage; (ii) is associated with activation of PLA2 that depends on intracellular calcium and lipid peroxidation; iii) does not depend on increased influx of extracellular calcium, and iv) depends on the effect of converging events (lipid peroxidation, intracellular calcium, activation of PLA2) on mitochondria to induce bioenergetic failure and necrosis. These interactions may play a role in alcohol liver toxicity, which requires polyunsaturated fatty acids, and involves induction of CYP2E1. PMID:17118330

  14. Understanding the Mechanism of the Hydrogen Abstraction from Arachidonic Acid Catalyzed by the Human Enzyme 15-Lipoxygenase-2. A Quantum Mechanics/Molecular Mechanics Free Energy Simulation.

    PubMed

    Suardíaz, Reynier; Jambrina, Pablo G; Masgrau, Laura; González-Lafont, Àngels; Rosta, Edina; Lluch, José M

    2016-04-12

    Lipoxygenases (LOXs) are a family of enzymes involved in the biosynthesis of several lipid mediators. In the case of human 15-LOX, the 15-LOX-1 and 15-LOX-2 isoforms show slightly different reaction regiospecificity and substrate specificity, indicating that substrate binding and recognition may be different, a fact that could be related to their different biological role. Here, we have used long molecular dynamics simulations, QM(DFT)/MM potential energy and free energy calculations (using the newly developed DHAM method), to investigate the binding mode of the arachidonic acid (AA) substrate into 15-LOX-2 and the rate-limiting hydrogen-abstraction reaction 15-LOX-2 catalyzes. Our results strongly indicate that hydrogen abstraction from C13 in 15-LOX-2 is only consistent with the "tail-first" orientation of AA, with its carboxylate group interacting with Arg429, and that only the pro-S H13 hydrogen will be abstracted (being the pro-R H13 and H10 too far from the acceptor oxygen atom). At the B3LYP/6-31G(d) level the potential and free energy barriers for the pro-S H13 abstraction of AA by 15-LOX-2 are 18.0 and 18.6 kcal/mol, respectively. To analyze the kinetics of the hydrogen abstraction process, we determined a Markov model corresponding to the unbiased simulations along the state-discretized reaction coordinate. The calculated rates based on the second largest eigenvalue of the Markov matrices agree well with experimental measurements, and also provide the means to directly determine the pre-exponential factor for the reaction by comparing with the free energy barrier height. Our calculated pre-exponential factor is close to the value of kBT/h. On the other hand, our results suggest that the spin inversion of the complete system (including the O2 molecule) that is required to happen at some point along the full process to lead to the final hydroperoxide product, is likely to take place during the hydrogen transfer, which is a proton coupled electron transfer

  15. An arachidonic acid-preferring acyl-CoA synthetase is a hormone-dependent and obligatory protein in the signal transduction pathway of steroidogenic hormones.

    PubMed

    Cornejo Maciel, Fabiana; Maloberti, Paula; Neuman, Isabel; Cano, Florencia; Castilla, Rocío; Castillo, Fernanda; Paz, Cristina; Podestá, Ernesto J

    2005-06-01

    We have described that, in adrenal and Leydig cells, the hormonal regulation of free arachidonic acid (AA) concentration is mediated by the concerted action of two enzymes: an acyl-CoA thioesterase (MTE-I or ARTISt) and an acyl-CoA synthetase (ACS4). In this study we analyzed the potential regulation of these proteins by hormonal action in steroidogenic cells. We demonstrated that ACS4 is rapidly induced by adrenocorticotropin (ACTH) and cAMP in Y1 adrenocortical cells. The hormone and its second messenger increased ACS4 protein levels in a time and concentration dependent way. Maximal concentration of ACTH (10 mIU/ml) produced a significant effect after 15 min of treatment and exerted the highest increase (3-fold) after 30 min. Moreover, (35)S-methionine incorporation showed that the increase in ACS4 protein levels is due to an increase in the de novo synthesis of the protein. On the contrary MTE-I protein levels in Y1 and MA-10 cells did not change after steroidogenic stimuli. In contrast with the effect observed on protein levels, stimulation of both cell lines did not change ACS4 RNA levels during the first hour of treatment, indicating that the effect of both stimuli is exerted at the level of ACS4 protein synthesis.StAR protein induction has a key role on the activation of steroidogenesis since this protein increases the rate of the limiting step of the whole process. In agreement with the fact that the inhibition of ACS4 activity by triacsin C blocks cAMP-stimulated progesterone production by MA-10 Leydig cells, here we demonstrated that ACS4 inhibition also reduces StAR protein levels. Moreover, exogenous AA was able to overcome the effect of triacsin C on both events, StAR induction and steroidogenesis. These results were confirmed by experiments using ACS4-targeted siRNA which result in a reduction in both ACS4 and StAR protein levels. The concomitant decrease in steroid production was overcome by the addition of AA to the knocked-out cells. In summary

  16. The effect of conjugated linoleic acids (CLA) supplementation on the activity of enzymes participating in the formation of arachidonic acid in liver microsomes of rats--probable mechanism of CLA anticancer activity.

    PubMed

    Stawarska, Agnieszka; Białek, Agnieszka; Stanimirova, Ivana; Stawarski, Tomasz; Tokarz, Andrzej

    2015-01-01

    The aim of the present research was to examine the effect of conjugated linoleic acids (CLA) supplementation on the activity of enzymes that take part in the synthesis of arachidonic acid (AA) and also to investigate the relation between their activity and the neoplastic process. The enzyme activities were established indirectly, because their measure was the amount of AA formed in vitro, being developed from linoleic acid as determined in liver microsomes of Spraque-Dawley rats. In addition, the indices of Δ⁶-desaturase (D6D) and Δ⁵-desaturase (D5D) were determined. To this aim, the method of high per-formance liquid chromatography with UV/VIS detection was used. Between the examined groups, statistically significant differences were observed in the activities of enzymes as well as D6D. The carcinogenic agent applied (DMBA) was found to significantly increase the activity of the examined enzymes. Negative correlation was found between the activities of desaturases and CLA supplementation, whereas the activity of those enzymes was a little higher in the group of rats with chemically induced cancer process. The neoplastic process has a stimulating effect on the activity of D6D. The decrease of D6D activity, resulting from the presence of CLA in the animals' diet, may confirm the anticancer properties of these isomers.

  17. Supplementation of arachidonic acid rich oil in European sea bass juveniles (Dicentrarchus labrax) diets: Effects on leucocytes and plasma fatty acid profiles, selected immune parameters and circulating prostaglandins levels.

    PubMed

    Torrecillas, S; Román, L; Rivero-Ramírez, F; Caballero, M J; Pascual, C; Robaina, L; Izquierdo, M S; Acosta, F; Montero, D

    2017-03-27

    The main objective of this study was to assess the effects of graded levels of dietary arachidonic acid (ARA), supplemented from alternative sources, on fatty acid composition of plasma and head kidney leucocytes of European sea bass (Dicentrarchus labrax). For that purpose, sea bass juveniles were fed four diets containing graded levels of ARA as follows: 0.5% (ARA0.5), 1% (ARA1), 2% (ARA2) and 4% (ARA4) during 60 days. At the end of the feeding trial fatty acid profiles of plasma and head kidney leucocytes were analyzed. Besides, plasma prostaglandins levels, head kidney leucocytes respiratory burst activity; peroxidase activity and phagocytic index were assayed. Reducing dietary ARA levels below 1% markedly reduced European sea bass growth performance. However, fish fed diet ARA0.5 tried to compensate this dietary ARA deficiency by a selective deposition of ARA on plasma and head kidney leucocytes, reaching similar levels to those fish fed diet ARA1 after 60 days of feeding. Nevertheless, head kidney phagocytic capacity was reduced as dietary ARA content in relation not only to variations on membrane composition but also to changes on fish basal prostaglandins levels. Results obtained demonstrated the importance to supply the necessary quantity n-6 LC-PUFA, and not only n-3 LC-PUFA levels, in European sea bass diets, in relation to not only growth performance but also immune system function.

  18. Relation of fatty acid composition in lead-exposed mallards to fat mobilization, lipid peroxidation and alkaline phosphatase activity

    USGS Publications Warehouse

    Mateo, R.; Beyer, W.N.; Spann, J.W.; Hoffman, D.J.

    2003-01-01

    The increase of n-6 polyunsaturated fatty acids (PUFA) in animal tissues has been proposed as a mechanism of Pb poisoning through lipid peroxidation or altered eicosanoids metabolism. We have studied fatty acid (FA) composition in liver and brain of mallards (Anas platyrhynchos) feeding for three weeks on diets containing combinations of low or high levels of vitamin E (20 or 200 UI/kg) and Pb (0 or 2 g/kg). Saturated FA, n-6 PUFA and total concentrations of FA were higher in livers of Pb-exposed mallards, but not in their brains. The percentage of n-6 PUFA in liver and brain was slightly higher in Pb-exposed mallards. The increase of n-6 PUFA in liver was associated with increased triglycerides and cholesterol in plasma, thus could be in part attributed to feed refusal and fat mobilization. The hepatic ratios between adrenic acid (22:4 n-6) and arachidonic acid (20:4 n-6) or between adrenic acid and linoleic acid (18:2 n-6) were higher in Pb exposed birds, supporting the existing hypothesis of increased fatty acid elongation by Pb. Among the possible consequences of increased n-6 PUFA concentration in tissues, we found increased lipid peroxidation in liver without important histopathological changes, and decreased plasma alkaline phosphatase activity that may reflect altered bone metabolism in birds.

  19. Cross-validated stable-isotope dilution GC-MS and LC-MS/MS assays for monoacylglycerol lipase (MAGL) activity by measuring arachidonic acid released from the endocannabinoid 2-arachidonoyl glycerol.

    PubMed

    Kayacelebi, Arslan Arinc; Schauerte, Celina; Kling, Katharina; Herbers, Jan; Beckmann, Bibiana; Engeli, Stefan; Jordan, Jens; Zoerner, Alexander A; Tsikas, Dimitrios

    2017-03-15

    2-Arachidonoyl glycerol (2AG) is an endocannabinoid that activates cannabinoid (CB) receptors CB1 and CB2. Monoacylglycerol lipase (MAGL) inactivates 2AG through hydrolysis to arachidonic acid (AA) and glycerol, thus modulating the activity at CB receptors. In the brain, AA released from 2AG by the action of MAGL serves as a substrate for cyclooxygenases which produce pro-inflammatory prostaglandins. Here we report stable-isotope GC-MS and LC-MS/MS assays for the reliable measurement of MAGL activity. The assays utilize deuterium-labeled 2AG (d8-2AG; 10μM) as the MAGL substrate and measure deuterium-labeled AA (d8-AA; range 0-1μM) as the MAGL product. Unlabelled AA (d0-AA, 1μM) serves as the internal standard. d8-AA and d0-AA are extracted from the aqueous buffered incubation mixtures by ethyl acetate. Upon solvent evaporation the residue is reconstituted in the mobile phase prior to LC-MS/MS analysis or in anhydrous acetonitrile for GC-MS analysis. LC-MS/MS analysis is performed in the negative electrospray ionization mode by selected-reaction monitoring the mass transitions [M-H](-)→[M-H - CO2](-), i.e., m/z 311→m/z 267 for d8-AA and m/z 303→m/z 259 for d0-AA. Prior to GC-MS analysis d8-AA and d0-AA were converted to their pentafluorobenzyl (PFB) esters by means of PFB-Br. GC-MS analysis is performed in the electron-capture negative-ion chemical ionization mode by selected-ion monitoring the ions [M-PFB](-), i.e., m/z 311 for d8-AA and m/z 303 for d0-AA. The GC-MS and LC-MS/MS assays were cross-validated. Linear regression analysis between the concentration (range, 0-1μM) of d8-AA measured by LC-MS/MS (y) and that by GC-MS (x) revealed a straight line (r(2)=0.9848) with the regression equation y=0.003+0.898x, indicating a good agreement. In dog liver, we detected MAGL activity that was inhibitable by the MAGL inhibitor JZL-184. Exogenous eicosatetraynoic acid is suitable as internal standard for the quantitative determination of d8-AA produced from d8

  20. Inhibitory effects of Tabebuia impetiginosa inner bark extract on platelet aggregation and vascular smooth muscle cell proliferation through suppressions of arachidonic acid liberation and ERK1/2 MAPK activation.

    PubMed

    Son, Dong-Ju; Lim, Yong; Park, Young-Hyun; Chang, Sung-Keun; Yun, Yeo-Pyo; Hong, Jin-Tae; Takeoka, Gary R; Lee, Kwang-Geun; Lee, Sung-Eun; Kim, Mi-Ran; Kim, Jeong-Han; Park, Byeoung-Soo

    2006-11-03

    The antiplatelet and antiproliferative activities of extract of Tabebuia impetiginosa inner bark (taheebo) were investigated using washed rabbit platelets and cultured rat aortic vascular smooth muscle cells (VSMCs) in vitro. n-Hexane, chloroform and ethyl acetate fractions showed marked and selective inhibition of platelet aggregation induced by collagen and arachidonic acid (AA) in a dose-dependent manner. These fractions, especially the chloroform fraction, also significantly suppressed AA liberation induced by collagen in [(3)H]AA-labeled rabbit platelets. The fractions, especially the chloroform fraction, potently inhibited cell proliferation and DNA synthesis induced by platelet derived growth factor (PDGF)-BB, and inhibited the levels of phosphorylated extracellular signal regulated kinase (ERK1/2) mitogen activated protein kinase (MAPK) stimulated by PDGF-BB, in the same concentration range that inhibits VSMC proliferation and DNA synthesis.

  1. The effect of dietary arachidonic acid (ARA) on growth performance, fatty acid composition and expression of ARA metabolism-related genes in larval half-smooth tongue sole (Cynoglossus semilaevis).

    PubMed

    Yuan, Yuhui; Li, Songlin; Mai, Kangsen; Xu, Wei; Zhang, Yanjiao; Ai, Qinghui

    2015-05-28

    The present study was conducted to investigate the effects of dietary arachidonic acid (ARA) on growth performance, fatty acid composition and ARA metabolism-related gene expression in larval half-smooth tongue sole (Cynoglossus semilaevis). Larvae (35 d after hatching, 54 (SEM 1) mg) were fed diets with graded concentrations of ARA (0.01, 0.39, 0.70, 1.07, 1.42 and 2.86 % dry weight) five times per d to apparent satiation for 30 d. Results showed that increased dietary ARA concentration caused a significant non-linear rise to a plateau in survival rate, final body weight and thermal growth coefficient, and the maximum values occurred with the 1.42 % ARA treatment. As dietary ARA increased to 1.07 or 1.42 %, activities of trypsin, leucine aminopeptidase and alkaline phosphatase levels increased, but they decreased with higher ARA concentrations. The fatty acid composition of tongue sole larvae was almost well correlated with their dietary fatty acid profiles, and the EPA content of the larvae decreased with increasing dietary ARA. Meanwhile, the partial sequences of COX-1a (cyclo-oxygenase-1a), COX-1b (cyclo-oxygenase-1b), COX-2 (cyclo-oxygenase-2), 5-LOX (5-lipoxygenase) and CYP2J6-like (cytochrome P450 2J6-like) were also obtained. Both COX-2 and 5-LOX mRNA expression levels significantly increased to a plateau in an 'L'-shaped manner as dietary ARA increased to 1.07 or 1.42 %, but no significant differences were found in the gene expression of COX-1a, COX-1b or CYP2J6-like. These results suggest that 1.07-1.42 % dietary ARA was beneficial to the growth performance of larval tongue sole, and the regulation of dietary ARA on the growth performance of larvae was probably involved in altering the mRNA expression of COX-2 and 5-LOX.

  2. A rapid method for determining arachidonic:eicosapentaenoic acid ratios in whole blood lipids: correlation with erythrocyte membrane ratios and validation in a large Italian population of various ages and pathologies

    PubMed Central

    2010-01-01

    Background Omega-3 and -6 polyunsaturated fatty acids (LCPUFA), are important for good health conditions. They are present in membrane phospholipids. The ratio of total n-6:n-3 LCPUFA and arachidonic acid:eicosapentaenoic acid (AA and EPA), should not exceed 5:1. Increased intake of n-6 and decreased consumption of n-3 has resulted in much higher, ca 10/15:1 ratio in RBC fatty acids with the possible appearance of a pathological "scenario". The determination of RBC phospholipid LCPUFA contents and ratios is the method of choice for assessing fatty acid status but it is labour intensive and time consuming. Aims of the study [i] To describe and validate a rapid method, suitable for large scale population studies, for total blood fatty acid assay; [ii] to verify a possible correlation between total n-6:n-3 ratio and AA:EPA ratios in RBC phospholipids and in whole-blood total lipids, [iii] to assess usefulness of these ratio as biomarkers of LCPUFA status. Methods [1] Healthy volunteers and patients with various pathologies were recruited. [2] Fatty acid analyses by GC of methyl esters from directly derivatized whole blood total lipids and from RBC phospholipids were performed on fasting blood samples from 1432 subjects categorised according to their age, sex and any existing pathologies. AA:EPA ratio and the total n-6:n-3 ratio were determined. Results AA:EPA ratio is a more sensitive and reliable index for determining changes in total blood fatty acid and it is correlated with the ratio derived from extracted RBC phospholipids. Conclusions The described AA:EPA ratio is a simple, rapid and reliable method for determining n-3 fatty acid status. PMID:20105293

  3. Altered Arachidonate Distribution in Macrophages from Caveolin-1 Null Mice Leading to Reduced Eicosanoid Synthesis*

    PubMed Central

    Astudillo, Alma M.; Pérez-Chacón, Gema; Meana, Clara; Balgoma, David; Pol, Albert; del Pozo, Miguel A.; Balboa, María A.; Balsinde, Jesús

    2011-01-01

    In this work we have studied the effect of caveolin-1 deficiency on the mechanisms that regulate free arachidonic acid (AA) availability. The results presented here demonstrate that macrophages from caveolin-1-deficient mice exhibit elevated fatty acid incorporation and remodeling and a constitutively increased CoA-independent transacylase activity. Mass spectrometry-based lipidomic analyses reveal stable alterations in the profile of AA distribution among phospholipids, manifested by reduced levels of AA in choline glycerophospholipids but elevated levels in ethanolamine glycerophospholipids and phosphatidylinositol. Furthermore, macrophages from caveolin-1 null mice show decreased AA mobilization and prostaglandin E2 and LTB4 production upon cell stimulation. Collectively, these results provide insight into the role of caveolin-1 in AA homeostasis and suggest an important role for this protein in the eicosanoid biosynthetic response. PMID:21852231

  4. Fatty acid mobilization and comparison to milk fatty acid content in northern elephant seals.

    PubMed

    Fowler, Melinda A; Debier, Cathy; Mignolet, Eric; Linard, Clementine; Crocker, Daniel E; Costa, Daniel P

    2014-01-01

    A fundamental feature of the life history of true seals, bears and baleen whales is lactation while fasting. This study examined the mobilization of fatty acids from blubber and their subsequent partitioning into maternal metabolism and milk production in northern elephant seals (Mirounga angustirostris). The fatty acid composition of blubber and milk was measured in both early and late lactation. Proportions of fatty acids in milk and blubber were found to display a high degree of similarity both early and late in lactation. Seals mobilized an enormous amount of lipid (~66 kg in 17 days), but thermoregulatory fatty acids, those that remain fluid at low temperatures, were relatively conserved in the outer blubber layer. Despite the stratification, the pattern of mobilization of specific fatty acids conforms to biochemical predictions. Long chain (>20C) monounsaturated fatty acids (MUFAs) were the least mobilized from blubber and the only class of fatty acids that showed a proportional increase in milk in late lactation. Polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) were more mobilized from the blubber, but neither proportion increased in milk at late lactation. These data suggest that of the long chain MUFA mobilized, the majority is directed to milk synthesis. The mother may preferentially use PUFA and SFA for her own metabolism, decreasing the availability for deposition into milk. The potential impacts of milk fatty acid delivery on pup diving development and thermoregulation are exciting avenues for exploration.

  5. Roles of tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, platelet-activating factor, and arachidonic acid metabolites in interleukin-1-induced resistance to infection in neutropenic mice.

    PubMed Central

    Vogels, M T; Hermsen, C C; Huys, H L; Eling, W M; van der Meer, J W

    1994-01-01

    Treatment with a single low dose (80 to 800 ng) of interleukin-1 (IL-1) 24 h before a lethal bacterial challenge in granulocytopenic and in normal mice enhances nonspecific resistance. The mechanism behind this protection has only partially been elucidated. Since IL-1 induces production of tumor necrosis factor alpha (TNF-alpha), granulocyte-macrophage colony-stimulating factor (GM-CSF), platelet-activating factor (PAF), and arachidonic acid metabolites, we investigated the potential role of these substances in IL-1-induced protection. Low doses of murine TNF-alpha but not of human TNF-alpha enhanced survival, suggesting an effect via the type II TNF receptor rather than the type I TNF receptor, which has little species specificity. In line with this TNF-alpha-induced protection from infection, pretreatment with a low dose of a rat anti-murine TNF-alpha monoclonal antibody tended to inhibit IL-1-induced protection, suggesting a role of TNF-alpha as a mediator of IL-1-induced enhanced resistance to infection. Pretreatment with higher doses of anti-TNF-alpha, however, showed a dose-related protective effect per se, which could be further enhanced by a suboptimal dose of IL-1. A combination of optimal doses of anti-TNF-alpha and IL-1 produced an increase in survival similar to that produced by separate pretreatments. This lack of further enhancement of survival by combined optimal pretreatments suggests a similar mechanism of protection, most likely attenuation of deleterious effects of overproduced proinflammatory cytokines like TNF-alpha during lethal infection. Pretreatment with different doses of GM-CSF before a lethal Pseudomonas aeruginosa challenge in neutropenic mice did not enhance survival. Different doses of WEB 2170, a selective PAF receptor antagonist, of MK-886, a selective inhibitor of leukotriene biosynthesis, or of several cyclooxygenase inhibitors did not reduce the protective effect of IL-1 pretreatment. We conclude that IL-1-induced nonspecific

  6. Arachidonate is a potent modulator of human heat shock gene transcription.

    PubMed Central

    Jurivich, D A; Sistonen, L; Sarge, K D; Morimoto, R I

    1994-01-01

    Cell and tissue injury activate the inflammatory response through the action(s) of arachidonic acid and its metabolites, leading to the expression of acute-phase proteins and inflammatory cytokines. At the molecular level, little is known how arachidonic acid regulates the inflammatory response. As inflammation is also associated with local increase in tissue temperatures, we examined whether arachidonic acid was directly involved in the heat shock response. Extracellular exposure to arachidonic acid induced heat shock gene transcription in a dose-dependent manner via acquisition of DNA-binding activity and phosphorylation of heat shock factor 1 (HSF1). In addition, exposure of cells to low concentrations of arachidonic acid, which by themselves did not induce HSF1 DNA-binding activity, reduced the temperature threshold for HSF1 activation from elevated temperatures which are not physiologically relevant (> 42 degrees C) to temperatures which can be attained during the febrile response (39-40 degrees C). These results indicate that elevated heat shock gene expression is a direct consequence of an arachidonic acid-mediated cellular response. Images PMID:8134388

  7. Selective Inhibition of Human Group IIA-secreted Phospholipase A2 (hGIIA) Signaling Reveals Arachidonic Acid Metabolism Is Associated with Colocalization of hGIIA to Vimentin in Rheumatoid Synoviocytes*

    PubMed Central

    Lee, Lawrence K.; Bryant, Katherine J.; Bouveret, Romaric; Lei, Pei-Wen; Duff, Anthony P.; Harrop, Stephen J.; Huang, Edwin P.; Harvey, Richard P.; Gelb, Michael H.; Gray, Peter P.; Curmi, Paul M.; Cunningham, Anne M.; Church, W. Bret; Scott, Kieran F.

    2013-01-01

    Human group IIA secreted phospholipase A2 (hGIIA) promotes tumor growth and inflammation and can act independently of its well described catalytic lipase activity via an alternative poorly understood signaling pathway. With six chemically diverse inhibitors we show that it is possible to selectively inhibit hGIIA signaling over catalysis, and x-ray crystal structures illustrate that signaling involves a pharmacologically distinct surface to the catalytic site. We demonstrate in rheumatoid fibroblast-like synoviocytes that non-catalytic signaling is associated with rapid internalization of the enzyme and colocalization with vimentin. Trafficking of exogenous hGIIA was monitored with immunofluorescence studies, which revealed that vimentin localization is disrupted by inhibitors of signaling that belong to a rare class of small molecule inhibitors that modulate protein-protein interactions. This study provides structural and pharmacological evidence for an association between vimentin, hGIIA, and arachidonic acid metabolism in synovial inflammation, avenues for selective interrogation of hGIIA signaling, and new strategies for therapeutic hGIIA inhibitor design. PMID:23482564

  8. Arachidonic and Linoleic Acid Derivatives Impact Oocyte ICSI Fertilization – A Prospective Analysis of Follicular Fluid and a Matched Oocyte in a ‘One Follicle – One Retrieved Oocyte – One Resulting Embryo’ Investigational Setting

    PubMed Central

    Bączkowski, Tomasz; Drozd, Arleta; Kazienko, Anna

    2015-01-01

    Objective To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI). Methodology Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle – one retrieved oocyte – one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA2) was determined by enzyme-linked immunosorbent assay. Principal Findings Increased activity of sPLA2 and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found. Conclusions/Significance Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their

  9. Intake of farmed Atlantic salmon fed soybean oil increases hepatic levels of arachidonic acid-derived oxylipins and ceramides in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of vegetable ingredients in fish feed has affected the fatty acid composition in farmed Atlantic salmon (Salmo salar L). Here we investigated how changes in fish feed affected the metabolism of mice fed diets containing fillets from such farmed salmon. We demonstrate that replacement of...

  10. Nuclear Factor of Activated T Cells-dependent Down-regulation of the Transcription Factor Glioma-associated Protein 1 (GLI1) Underlies the Growth Inhibitory Properties of Arachidonic Acid*

    PubMed Central

    Comba, Andrea; Almada, Luciana L.; Tolosa, Ezequiel J.; Iguchi, Eriko; Marks, David L.; Vara Messler, Marianela; Silva, Renata; Fernandez-Barrena, Maite G.; Enriquez-Hesles, Elisa; Vrabel, Anne L.; Botta, Bruno; Di Marcotulio, Lucia; Ellenrieder, Volker; Eynard, Aldo R.; Pasqualini, Maria E.; Fernandez-Zapico, Martin E.

    2016-01-01

    Numerous reports have demonstrated a tumor inhibitory effect of polyunsaturated fatty acids (PUFAs). However, the molecular mechanisms modulating this phenomenon are in part poorly understood. Here, we provide evidence of a novel antitumoral mechanism of the PUFA arachidonic acid (AA). In vivo and in vitro experiments showed that AA treatment decreased tumor growth and metastasis and increased apoptosis. Molecular analysis of this effect showed significantly reduced expression of a subset of antiapoptotic proteins, including BCL2, BFL1/A1, and 4-1BB, in AA-treated cells. We demonstrated that down-regulation of the transcription factor glioma-associated protein 1 (GLI1) in AA-treated cells is the underlying mechanism controlling BCL2, BFL1/A1, and 4-1BB expression. Using luciferase reporters, chromatin immunoprecipitation, and expression studies, we found that GLI1 binds to the promoter of these antiapoptotic molecules and regulates their expression and promoter activity. We provide evidence that AA-induced apoptosis and down-regulation of antiapoptotic genes can be inhibited by overexpressing GLI1 in AA-sensitive cells. Conversely, inhibition of GLI1 mimics AA treatments, leading to decreased tumor growth, cell viability, and expression of antiapoptotic molecules. Further characterization showed that AA represses GLI1 expression by stimulating nuclear translocation of NFATc1, which then binds the GLI1 promoter and represses its transcription. AA was shown to increase reactive oxygen species. Treatment with antioxidants impaired the AA-induced apoptosis and down-regulation of GLI1 and NFATc1 activation, indicating that NFATc1 activation and GLI1 repression require the generation of reactive oxygen species. Collectively, these results define a novel mechanism underlying AA antitumoral functions that may serve as a foundation for future PUFA-based therapeutic approaches. PMID:26601952

  11. Effect of resveratrol, tyrosol and beta-sitosterol on oxidised low-density lipoprotein-stimulated oxidative stress, arachidonic acid release and prostaglandin E2 synthesis by RAW 264.7 macrophages.

    PubMed

    Vivancos, Marta; Moreno, Juan J

    2008-06-01

    Oxidation of LDL is hypothesised as an early and critical event in atherogenesis. Oxidised LDL (oxLDL) favour the transformation of macrophages into foam cells, an important cell involved in atherosclerosis. Furthermore, oxLDL cause multiple changes in macrophage functions. Thus, oxLDL induces certain genes, suppresses others and alters cell lipid metabolism. Consumption of a Mediterranean diet is associated with a low incidence of atherosclerotic disease, but data about the specific dietary constituents involved and mechanisms conferring cardioprotection are still sparse. The aim of the present study was to determine the effect of representative minor components of wine and olive oil on reactive oxygen species and eicosanoid synthesis induced by oxLDL-stimulated macrophages. We observed that exposure to non-toxic oxLDL concentrations leads to the production of H2O2 by RAW 264.7 macrophages and this effect was reverted by apocynin, a NADPH oxidase inhibitor. Moreover, oxLDL induced arachidonic acid (AA) release, cyclo-oxygenase-2 overexpression and subsequent PGE2 release. We observed that resveratrol and tyrosol revert H2O2 production induced by oxLDL as well as AA release and PGE2 synthesis and that these effects were not as a consequence of these compounds interfering with the oxLDL binding to their receptors. Interestingly, beta-sitosterol presence enhances these polyphenol actions. Thus, we found a synergistic action of polyphenols of olive oil and wine and beta-sitosterol of olive oil led to the modulation of the effects of oxLDL on oxidative stress and PGE2 synthesis.

  12. Production of 5,8,11-Eicosatrienoic Acid (Mead Acid) by a (Delta)6 Desaturation Activity-Enhanced Mutant Derived from a (Delta)12 Desaturase-Defective Mutant of an Arachidonic Acid-Producing Fungus, Mortierella alpina 1S-4.

    PubMed

    Kawashima, H; Nishihara, M; Hirano, Y; Kamada, N; Akimoto, K; Konishi, K; Shimizu, S

    1997-05-01

    Enhanced production of 5,8,11-eicosatrienoic acid (Mead acid, 20:3(omega)9) was attained by a mutant fungus, Mortierella alpina M209-7, derived from (Delta)12 desaturase-defective M. alpina Mut48. The 20:3(omega)9 production by M209-7 was 1.3 times greater than that by its parent strain, Mut48. This is thought to be due to its enhanced (Delta)6 desaturation activity, which was 1.4 times higher than that of Mut48. In both strains, 87 to 88% of the total lipids comprised triacylglycerol (TG) and 85% of 20:3(omega)9 was contained in TG. On optimization of the culture conditions for M209-7, earlier glucose feeding and shifting of the growth temperature from 28 to 19(deg)C on the second day were shown to be effective. Under the optimal conditions with a 10-liter jar fermentor, 20:3(omega)9 production reached 1.65 g/liter of culture medium (corresponding to 118 mg/g of dry mycelia and 28.9% of total fatty acids), which is about twice that reported previously (0.8 g/liter).

  13. Dexamethasone blocks arachidonate biosynthesis in isolated hepatocytes and cultured hepatoma cells

    SciTech Connect

    Marra, C.A.; de Alaniz, M.J.; Brenner, R.R.

    1986-03-01

    The effect of dexamethasone on the incorporation and conversion of (1-14C)eicosa-8,11,14-trienoic acid to arachidonic acid in isolated hepatocytes and in hepatoma tissue culture (HTC) cells was studied. In both kinds of cells, no changes in the exogenous acid incorporation were found when the hormone was added to the incubation media at 0.1 or 0.2 mM concentration, while the biosynthesis of arachidonic acid was significantly depressed. The effect on the biosynthesis was faster in isolated normal liver cells (60 min) than in tumoral cells (120 min) and reached an inhibition of ca. 50% after 3 hr of treatment. The addition of cycloheximide (10(-6) M) also caused a marked decrease in the biosynthesis of this polyunsaturated fatty acid, but when dexamethasone was added to the media simultaneously with cycloheximide, a synergistic action was not observed. The results obtained show that protein synthesis would be involved in the modulation of the biosynthesis of arachidonic acid by glucocorticoids. The changes in the delta 5 desaturation of labeled 20:3 omega 6 to arachidonic acid correlated with changes in the fatty acid composition in isolated cells.

  14. Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids

    USGS Publications Warehouse

    Lawrence, G.B.; Sutherland, J.W.; Boylen, C.W.; Nierzwicki-Bauer, S. W.; Momen, B.; Baldigo, Barry P.; Simonin, H.A.

    2007-01-01

    Assessments of acidic deposition effects on aquatic ecosystems have often been hindered by complications from naturally occurring organic acidity. Measurements of pH and ANCG, the most commonly used indicators of chemical effects, can be substantially influenced by the presence of organic acids. Relationships between pH and inorganic Al, which is toxic to many forms of aquatic biota, are also altered by organic acids. However, when inorganic Al concentrations are plotted against ANC (the sum of Ca2+, Mg 2+, Na+, and K+, minus SO42-, NO3-, and Cl-), a distinct threshold for Al mobilization becomes apparent. If the concentration of strong organic anions is included as a negative component of ANC, the threshold occurs at an ANC value of approximately zero, the value expected from theoretical charge balance constraints. This adjusted ANC is termed the base-cation surplus. The threshold relationship between the base-cation surplus and Al was shown with data from approximately 200 streams in the Adirondack region of New York, during periods with low and high dissolved organic carbon concentrations, and for an additional stream from the Catskill region of New York. These results indicate that (1) strong organic anions can contribute to the mobilization of inorganic Al in combination with SO42- and NO 3-, and (2) the presence of inorganic Al in surface waters is an unambiguous indication of acidic deposition effects. ?? 2007 American Chemical Society.

  15. Acid rain effects on aluminum mobilization clarified by inclusion of strong organic acids.

    PubMed

    Lawrence, G B; Sutherland, J W; Boylen, C W; Nierzwicki-Bauer, S W; Momen, B; Baldigo, B P; Simonin, H A

    2007-01-01

    Assessments of acidic deposition effects on aquatic ecosystems have often been hindered by complications from naturally occurring organic acidity. Measurements of pH and ANCG, the most commonly used indicators of chemical effects, can be substantially influenced by the presence of organic acids. Relationships between pH and inorganic Al, which is toxic to many forms of aquatic biota, are also altered by organic acids. However, when inorganic Al concentrations are plotted against ANC (the sum of Ca2+, Mg2+, Na+, and K+, minus S042-, N03-, and Cl-), a distinct threshold for Al mobilization becomes apparent. If the concentration of strong organic anions is included as a negative component of ANC, the threshold occurs at an ANC value of approximately zero, the value expected from theoretical charge balance constraints. This adjusted ANC is termed the base-cation surplus. The threshold relationship between the base-cation surplus and Al was shown with data from approximately 200 streams in the Adirondack region of New York, during periods with low and high dissolved organic carbon concentrations, and for an additional stream from the Catskill region of New York. These results indicate that (1) strong organic anions can contribute to the mobilization of inorganic Al in combination with SO42- and N03-, and (2) the presence of inorganic Al in surface waters is an unambiguous indication of acidic deposition effects.

  16. Growth hormone releasing factor (GRF) increases free arachidonate levels in the pituitary: a role for lipoxygenase products

    SciTech Connect

    Canonico, P.L.; Speciale, C.; Sortino, M.A.; Cronin, M.J.; MacLeod, R.M.; Scapagnini, U.

    1986-01-20

    GRF, a specific stimulator of GH release, increased in a concentration- and time-dependent manner pituitary (/sup 3/H)-arachidonate levels in vitro. This effect was antagonized by 100 nM somatostatin. Exogenous arachidonate also stimulated GH release in vitro. Quinacrine, a phospholipase A2 inhibitor, reduced both basal and GRF-stimulated free arachidonate levels as well as GH release. The cyclooxygenase inhibitor indomethacin was ineffective, while BW755c, which also inhibits the lipoxygenase pathway, produced a further increase in the levels of the fatty acid stimulated by GRF and potently reduced GH release. These results provide additional evidence for the involvement of arachidonate metabolism in the hormone-releasing effect of GRF at the somatotroph. 14 references, 1 figure, 2 tables.

  17. Selective mobilization of fatty acids from adipose tissue in migratory birds.

    PubMed

    Price, Edwin R; Krokfors, Anna; Guglielmo, Christopher G

    2008-01-01

    During times of high energy demand, stored fatty acids are mobilized from adipocytes. This mobilization has previously been shown to be a non-random process, with more hydrophilic fatty acids being mobilized most readily. The objectives of this study were to characterize the relative mobilization of fatty acids from adipocytes in two migratory bird species and to investigate possible changes in selective fatty acid mobilization associated with the migratory period. Captive ruffs (Philomachus pugnax) and white-crowned sparrows (Zonotrichia leucophrys) were studied. The sparrows were divided into two treatments: 'winter' (photoperiod 8 h:16 h L:D) and 'migrant' (in which migratory condition was induced with a photoperiodic manipulation of 8 h:16 h L:D, followed by 16 h:8 h L:D). Adipose tissue was removed from ruffs and sparrows and incubated for 90 min after stimulation with epinephrine. The proportions of individual fatty acid species released into the incubation medium were compared with their proportions in the adipocytes to determine relative mobilizations. We found that patterns of relative mobilization in ruffs and sparrows are similar to those of mammals, with shorter chain lengths and more double bonds leading to higher relative mobilization. Seasonal condition in sparrows did not alter this pattern. This pattern of relative mobilization from adipocytes seems to be a general rule amongst birds and mammals and should be considered before inferring functionality about selective retention or mobilization of certain fatty acids. The composition of adipose stores in birds may affect migratory performance; however, our results indicate that patterns of relative mobilization at the adipocytes do not vary with season in migratory birds.

  18. Effects of C18 Fatty Acids on Intracellular Ca(2+) Mobilization and Histamine Release in RBL-2H3 Cells.

    PubMed

    Kim, Myung Chul; Kim, Min Gyu; Jo, Young Soo; Song, Ho Sun; Eom, Tae In; Sim, Sang Soo

    2014-06-01

    To investigate the underlying mechanisms of C18 fatty acids (stearic acid, oleic acid, linoleic acid and α-linolenic acid) on mast cells, we measured the effect of C18 fatty acids on intracellular Ca(2+) mobilization and histamine release in RBL-2H3 mast cells. Stearic acid rapidly increased initial peak of intracellular Ca(2+) mobilization, whereas linoleic acid and α-linolenic acid gradually increased this mobilization. In the absence of extracellular Ca(2+), stearic acid (100 µM) did not cause any increase of intracellular Ca(2+) mobilization. Both linoleic acid and α-linolenic acid increased intracellular Ca(2+) mobilization, but the increase was smaller than that in the presence of extracellular Ca(2+). These results suggest that C18 fatty acid-induced intracellular Ca(2+) mobilization is mainly dependent on extracellular Ca(2+) influx. Verapamil dose-dependently inhibited stearic acid-induced intracellular Ca(2+) mobilization, but did not affect both linoleic acid and α-linolenic acid-induced intracellular Ca(2+) mobilization. These data suggest that the underlying mechanism of stearic acid, linoleic acid and α-linolenic acid on intracellular Ca(2+) mobilization may differ. Linoleic acid and α-linolenic acid significantly increased histamine release. Linoleic acid (C18:2: ω-6)-induced intracellular Ca(2+) mobilization and histamine release were more prominent than α-linolenic acid (C18:3: ω-3). These data support the view that the intake of more α-linolenic acid than linoleic acid is useful in preventing inflammation.

  19. Effects of C18 Fatty Acids on Intracellular Ca2+ Mobilization and Histamine Release in RBL-2H3 Cells

    PubMed Central

    Kim, Myung Chul; Kim, Min Gyu; Jo, Young Soo; Song, Ho Sun; Eom, Tae In

    2014-01-01

    To investigate the underlying mechanisms of C18 fatty acids (stearic acid, oleic acid, linoleic acid and α-linolenic acid) on mast cells, we measured the effect of C18 fatty acids on intracellular Ca2+ mobilization and histamine release in RBL-2H3 mast cells. Stearic acid rapidly increased initial peak of intracellular Ca2+ mobilization, whereas linoleic acid and α-linolenic acid gradually increased this mobilization. In the absence of extracellular Ca2+, stearic acid (100 µM) did not cause any increase of intracellular Ca2+ mobilization. Both linoleic acid and α-linolenic acid increased intracellular Ca2+ mobilization, but the increase was smaller than that in the presence of extracellular Ca2+. These results suggest that C18 fatty acid-induced intracellular Ca2+ mobilization is mainly dependent on extracellular Ca2+ influx. Verapamil dose-dependently inhibited stearic acid-induced intracellular Ca2+ mobilization, but did not affect both linoleic acid and α-linolenic acid-induced intracellular Ca2+ mobilization. These data suggest that the underlying mechanism of stearic acid, linoleic acid and α-linolenic acid on intracellular Ca2+ mobilization may differ. Linoleic acid and α-linolenic acid significantly increased histamine release. Linoleic acid (C18:2: ω-6)-induced intracellular Ca2+ mobilization and histamine release were more prominent than α-linolenic acid (C18:3: ω-3). These data support the view that the intake of more α-linolenic acid than linoleic acid is useful in preventing inflammation. PMID:24976764

  20. Lipid Profiling Reveals Arachidonate Deficiency in RAW264.7 Cells: Structural and Functional Implications†

    PubMed Central

    Rouzer, Carol A.; Ivanova, Pavlina T.; Byrne, Mark O.; Milne, Stephen B.; Marnett, Lawrence J.; Brown, H. Alex

    2008-01-01

    Glycerophospholipids containing arachidonic acid (20:4) serve as the precursors for an array of biologically active lipid mediators, most of which are produced by macrophages. We have applied mass spectrometry-based lipid profiling technology to evaluate the glycerophospholipid structure and composition of two macrophage populations, resident peritoneal macrophages and RAW264.7 cells, with regard to their potential for 20:4-based lipid mediator biosynthesis. Fatty acid analysis indicated that RAW264.7 cells were deficient in 20:4 (10 ± 1 mole percent) as compared to peritoneal macrophages (26 ± 1 mole percent). Mass spectrometry of total glycerophospholipids demonstrated a marked difference in the distribution of lipid species, including reduced levels of 20:4-containing lipids, in RAW264.7 cells as compared to peritoneal macrophages. Enrichment of RAW264.7 cells with 20:4 increased the fatty acid to 20 ± 1 mole percent. However, the distribution of the incorporated 20:4 remained different from that of peritoneal macrophages. RAW264.7 cells pretreated with granulocyte-macrophage colony stimulating factor followed by lipopolysaccharide and interferon-gamma mobilized similar quantities of 20:4 and produced similar amounts of prostaglandins as peritoneal macrophages treated with LPS alone. LPS treatment resulted in detectable changes in specific 20:4-containing glycerophospholipids in peritoneal cells, but not in RAW264.7 cells. 20:4-enriched RAW264.7 cells lost 88% of the incorporated fatty acid during the LPS incubation without additional prostaglandin synthesis. These results illustrate that large differences in glycerophospholipid composition may exist, even in closely related cell populations, and demonstrate the importance of interpreting the potential for lipid-mediator biosynthesis in the context of overall glycerophospholipid composition. PMID:17144673

  1. The opportunistic pathogen Pseudomonas aeruginosa carries a secretable arachidonate 15-lipoxygenase

    PubMed Central

    Vance, Russell E.; Hong, Song; Gronert, Karsten; Serhan, Charles N.; Mekalanos, John J.

    2004-01-01

    In mammals, lipoxygenases play key roles in inflammation by initiating the transformation of arachidonic acid into potent bioactive lipid mediators such as leukotrienes and lipoxins. In general, most bacteria are believed to lack lipoxygenases and their polyunsaturated fatty acid substrates. It is therefore of interest that an ORF (PA1169) with high homology to eukaryotic lipoxygenases was discovered by analysis of the whole-genome sequence of the opportunistic bacterial pathogen Pseudomonas aeruginosa. Using TLC and liquid chromatography-UV-tandem mass spectrometry (LC-UV-MS-MS), we demonstrate that PA1169 encodes a bacterial lipoxygenase (LoxA) that converts arachidonic acid into 15-hydroxyeicosatetraenoic acid (15-HETE). Although mammalian lipoxygenases are cytoplasmic enzymes, P. aeruginosa LoxA activity is secreted. Taken together, these results suggest a mechanism by which a pathogen-secreted lipoxygenase may modulate host defense and inflammation via alteration of the biosynthesis of local chemical mediators. PMID:14766977

  2. Mobilization of soil-borne arsenic by three common organic acids: Dosage and time effects.

    PubMed

    Onireti, Olaronke O; Lin, Chuxia

    2016-03-01

    A batch experiment was conducted to investigate the mobilization of soil-borne arsenic by three common low-molecular-weight organic acids with a focus on dosage and time effects. The results show that oxalic acid behaved differently from citric acid and malic acid in terms of mobilizing As that was bound to iron compounds. At an equivalent molar concentration, reactions between oxalic acid and soil-borne Fe were kinetically more favourable, as compared to those between either citric acid or malic acid and the soil-borne Fe. It was found that reductive dissolution of soil-borne Fe played a more important role in liberating As, as compared to non-reductive reactions. Prior to the 7th day of the experiment, As mobility increased with increasing dose of oxalic acid while there was no significant difference (P > 0.05) in mobilized As among the treatments with different doses of citric acid or malic acid. The dosage effect on soil-borne As mobilization in the citric acid and malic acid treatments became clear only after the 7th day of the experiment. Soluble Ca present in the soils could cause re-immobilization of As by competing with solution-borne Fe for available organic ligands to form practically insoluble organic compounds of calcium (i.e. calcium oxalate). This resulted in transformation of highly soluble organic complexes of iron (i.e. iron oxalate complexes) into slightly soluble organic compounds of iron (i.e. iron oxalate) or free ferric ion, which then reacted with the solution-borne arsenate ions to form practically insoluble iron arsenates in the latter part of the experiment.

  3. Unravelling the effects of mobile phase additives in supercritical fluid chromatography. Part I: Polarity and acidity of the mobile phase.

    PubMed

    West, Caroline; Melin, Jodie; Ansouri, Hassna; Mengue Metogo, Maïly

    2017-04-07

    The mobile phases employed in current supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). The polarity of such mobile phase compositions is here re-evaluated with a solvatochromic dye (Nile Red), particularly to assess the contribution of additives. It appears that additives, when employed in usual concentration range (0.1% or 20mM) do not modify the polarity in the immediate environment of the probe. In addition, the combination of carbon dioxide and an alcohol is known to form alkoxylcarbonic acid, supposedly conferring some acidic character to SFC mobile phases. Direct measurements of the apparent pH are impossible, but colour indicators of pH can be used to define the range of apparent pH provided by carbon dioxide-alcohol mixtures, with or without additives. Five colour indicators (Thymol Blue, Bromocresol Green, Methyl Red, Bromocresol Purple, and Bromothymol Blue) were selected to provide a wide range of aqueous pKa values (from 1.7 to 8.9). UV-vis absorption spectra measured in liquid phases of controlled pH were compared to those measured with a diode-array detector employed in SFC, with the help of chemometric methods. Based on these observations, it is concluded that the apparent pH range in carbon dioxide-methanol mobile phases is close to 5. Increasing the proportion of methanol (in the course of a gradient elution for instance) causes decreasing apparent pH. Strong acids can further decrease the apparent pH below 1.7; strong bases have little influence on the apparent pH, probably because, in this range of concentrations, they are titrated by alkoxylcarbonic acid or form ion pairs with alkoxycarbonate. However, bases and salts could stabilize the acidity in the course of gradient runs.

  4. Effects of coating of dicarboxylic acids on the mass-mobility relationship of soot particles.

    PubMed

    Xue, Huaxin; Khalizov, Alexei F; Wang, Lin; Zheng, Jun; Zhang, Renyi

    2009-04-15

    Atandem differential mobility analyzer (TDMA) and a differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) have been employed to study morphology and hygroscopicity of soot aerosol internally mixed with dicarboxylic acids. The effective densities, fractal dimensions, and dynamic shape factors of soot particles before and after coating with succinic and glutaric acids are determined. Coating of soot with succinic acid results in a significant increase in the particle mobility diameter, mass, and effective density, but these properties recover to their initial values once succinic acid is removed by heating, suggesting that no restructuring of the soot core occurs. This conclusion is also supported from the observation of similar fractal dimensions and dynamic shape factors for fresh and coated/heated soot aggregates. Also, no change is observed when succinic acid-coated aggregates are cycled through elevated relative humidity (5% to 90% to 5% RH) below the succinic acid deliquescence point. When soot is coated with glutaric acid, the particle mass increases, but the mobility diameter shrinks by 10-40%. Cycling the soot aerosol coated with glutaric acid through elevated relative humidity leads to an additional mass increase, indicating that condensed water remains within the coating even at low RH. The fractal dimension of soot particles increases after coating and remains high when glutaric acid is removed by heating. The dynamic shape factor of glutaric acid-coated and heated soot is significantly lower than that of fresh soot, suggesting a significant restructuring of the soot agglomerates by glutaric acid. The results imply that internal mixing of soot aerosol during atmospheric aging leads to changes in hygroscopicity, morphology, and effective density, which likely modify their effects on direct and indirect climate forcing and deposition in the human respiratory system.

  5. ENHANCED MOBILITY OF DENSE NONAQUEOUS-PHASE LIQUIDS (DNAPLs) USING DISSOLVED HUMIC ACIDS

    SciTech Connect

    EDWIN S. OLSON; JOHN R. GALLAGHER; MARC D. KURZ

    1998-10-01

    The specific objectives of this subtask are as follows: � Evaluate the suitability of using humic acids to enhance the solubility and mobility of DNAPL contaminants sorbed to soils. � Evaluate the toxicity and bioavailablity of the DNAPLs to biodegrading microorganisms. To meet the first objective, the Energy & Environmental Research Center (EERC) evaluated a set of humic acids (two) with different chemical compositions and polarities for the following: � Ability of the humates to mobilize/solubilize selected (three) DNAPLs � Mobilization/solubilization in batch soil�water experiments (one soil) � Removal rate via biotreatment with a well-established active microbial culture. The second objective was met by evaluating the inhibiting effects of a leonardite-derived humic acid on active microbial populations.

  6. Arachidonate 12-lipoxygenases with reference to their selective inhibitors

    SciTech Connect

    Yamamoto, Shozo . E-mail: yamamosh@kyoto-wu.ac.jp; Katsukawa, Michiko; Nakano, Ayumi; Hiraki, Emi; Nishimura, Kohji; Jisaka, Mitsuo; Yokota, Kazushige; Ueda, Natsuo

    2005-12-09

    Lipoxygenase is a dioxygenase recognizing a 1-cis,4-cis-pentadiene of polyunsaturated fatty acids. The enzyme oxygenates various carbon atoms of arachidonic acid as a substrate and produces 5-, 8-, 12- or 15-hydroperoxy eicosatetraenoic acid with a conjugated diene chromophore. The enzyme is referred to as 5-, 8-, 12- or 15-lipoxygenase, respectively. Earlier we found two isoforms of 12-lipoxygenase, leukocyte- and platelet-type enzymes, which were distinguished by substrate specificity, catalytic activity, primary structure, gene intron size, and antigenicity. Recently, the epidermis-type enzyme was found as the third isoform. Attempts have been made to find isozyme-specific inhibitors of 12-lipoxygenase, and earlier we found hinokitol, a tropolone, as a potent inhibitor selective for the platelet-type 12-lipoxygenase. More recently, we tested various catechins of tea leaves and found that (-)-geotechnical gallate was a potent and selective inhibitor of human platelet 12-lipoxygenase with an IC{sub 5} of 0.14 {mu}M. The compound was much less active with 12-lipoxygenase of leukocyte-type, 15-, 8-, and 5-lipoxygenases, and cyclo oxygenases-1 and -2.

  7. An in vitro investigation of the actions of reproductive hormones on the cervix of the ewe in the follicular stage: the effects of 17β-estradiol, oxytocin, FSH, and arachidonic acid on the cervical pathway for the synthesis of prostaglandin E2.

    PubMed

    Falchi, L; Scaramuzzi, R J

    2015-04-01

    During the periovulatory period, the cervix of the ewe relaxes and this mechanism is thought to be mediated by oxytocin and prostaglandin E2 (PGE2) in response to increased concentrations of 17β-estradiol and perhaps FSH. The aim of the study was to determine the in vitro effects of 17β-estradiol, FSH, oxytocin, and arachidonic acid (AA) on the synthesis of PGE2 and on the expression of oxytocin receptor (OTR), cytoplasmic phospholipase A2 (cPLA2), and cyclooxygenase 2 (COX-2) in explants of cervical tissue collected from ewes in the periovulatory phase of the estrous cycle. Cervical minces from ewes in the follicular phase of the estrous cycle were cultured in supplemented Eagle's Minimum Essential Medium for 48 hours with 17β-estradiol, FSH, oxytocin, or AA. After incubation, the tissue was stored at -80 °C and the media at -20 °C. Western immunoblotting was used to determine relative levels of OTR, cPLA2, and COX-2 in cervical tissue, and the media was analyzed by RIA, to determine the concentration of PGE2. The addition of 17β-estradiol increased the concentration of PGE2 in the media (P = 0.001), the levels of COX-2 (P = 0.02) and OTR (P = 0.006) but not those of cPLA2 (P = 0.15). The addition of FSH increased the levels of COX-2 (P = 0.01) but, it had no effect on the concentration of PGE2 (P = 0.08) or on the levels of OTR (P = 0.07) and cPLA2 (P = 0.15). Oxytocin did not increase the levels of COX-2 (P = 0.38) but increased those of OTR (P = 0.001) and cPLA2 (P = 0.01) but not on the concentration of PGE2 in the media. Arachidonic acid increased the levels of cPLA2 (P = 0.01) and those of COX-2 (P = 0.02) but not the concentration of PGE2 in the media. Our findings suggest that the PGE2-mediated mechanisms of cervical relaxation in the ewe during the follicular phase are stimulated by FSH, 17β-estradiol, oxytocin, and AA. They all appear to act by inducing receptors and enzymes along the synthetic pathway for PGE2.

  8. Interactive Computer-Assisted Instruction in Acid-Base Physiology for Mobile Computer Platforms

    ERIC Educational Resources Information Center

    Longmuir, Kenneth J.

    2014-01-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ~20 screens of information, on the subjects…

  9. Acidity-Facilitated Mobilization of Surface Clay Colloid from Natural Sand Medium

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Wang, C.; Mohanty, B. P.

    2010-12-01

    Colloid mobilization and migration in a soil system has attracted increasing scrutiny for its role in facilitating colloid-borne transport of contaminants in the environments. In many previous studies, pH was evoked as a major factor in mobilizing surface colloids through inducing favorable surface charge and electrostatic conditions. The possible direct role of acidity with H+ as a chemical agent has remained largely obscured behind the indirect role of pH. In this study, we demonstrated through column flow-through tests that cyclical elution of natural sand media with weak acid and base solutions can greatly facilitate detachment and transport of surface clay colloids. We found that while elevating pH to an alkaline condition helped release the loosely-attached surface clays, a pretreatment with H+ could facilitate the mobilization of chemically-bonded clay colloids through lysing of labile Ca and Mg ions. A quantitative relation was observed that 1 mmol H+ could lyse about 0.5 mmol Ca2+ and Mg2+ and subsequently resulted in a release of about 1,200 mg clay during base elution when repulsive force between particles dominated. Natural organic acids such as citric acid and acetic acid in environment-relevant low concentrations (<1mM and pH>5.0) were as effective as HCl with a stronger acidic condition. The small mass ratio of Ca and Mg over colloid released and the nature of weak acid used suggest that the mobilization was less likely due to dissolution of cement casing than lysing of labile interstitial Ca and Mg by H+, which severed Ca and Mg bridging bonds between particles. Natural acidity is generated in abundance from various bio- and geochemical processes; e.g., many plants produce citric acid through citric acid cycle metabolism; biodegradation of dead organic matter forms humic acids. We postulate that natural proton dynamics in tendon with pH oscillation accompanied with various soil biogeochemical processes could play a major role in subsurface clay

  10. Reduced Triacylglycerol Mobilization during Seed Germination and Early Seedling Growth in Arabidopsis Containing Nutritionally Important Polyunsaturated Fatty Acids

    PubMed Central

    Shrestha, Pushkar; Callahan, Damien L.; Singh, Surinder P.; Petrie, James R.; Zhou, Xue-Rong

    2016-01-01

    There are now several examples of plant species engineered to synthesize and accumulate nutritionally important polyunsaturated fatty acids in their seed triacylglycerols (TAG). The utilization of TAG in germinating seeds of such transgenic plants was unknown. In this study, we examined the TAG utilization efficiency during seed germination in transgenic Arabidopsis seeds containing several examples of these fatty acids. Seed TAG species with native fatty acids had higher utilization rate than the TAG species containing transgenically produced polyunsaturated fatty acids. Conversely, quantification of the fatty acid components remaining in the total TAG after early stages of seed germination revealed that the undigested TAGs tended to contain elevated levels of the engineered polyunsaturated fatty acids (PUFA). LC-MS analysis further revealed asymmetrical mobilization rates for the individual TAG species. TAGs which contained multiple PUFA fatty acids were mobilized slower than the species containing single PUFA. The mobilized engineered fatty acids were used in de novo membrane lipid synthesis during seedling development. PMID:27725822

  11. Selective mobilization of fatty acids in adipose tissue of heavy pigs.

    PubMed

    Bochicchio, D; Comellini, M; Lambertini, P; Marchetto, G; Della Casa, G

    2015-01-01

    The mobilization of fatty acids during food deprivation is a selective process studied in different species (humans, rodents, birds, viverrids). The aim of this work was to study the effect of fasting on selective mobilization in commercial pigs. A total of 16 barrows (Large White×Landrace (167 kg±12.5 kg live weight) were subdivided into two homogeneous groups, one subjected to 12 h and the other to 60 h of fasting (fasting time) before slaughtering. For each pig inner and outer backfat layer were sampled at slaughter and at ham trimming 24 h later (sampling time). Increasing the fasting time and the sampling time after slaughter caused an increase in the amount of free fatty acids in both layers. Therefore it can be argued that during fasting lipolysis is stimulated and remains active also after slaughtering. The factors that stimulate lipolysis determine a greater mobilization of unsaturated fatty acids than saturated ones. Thus fasting time may influence the suitability of pork for processing and conservation, since free fatty acids are more suitable for oxidation than the esterified ones.

  12. Mobilization

    DTIC Science & Technology

    1987-01-01

    istic and romantic emotionalism that typifies this genre. Longino, James C., et al. “A Study of World War Procurement and Industrial Mobilization...States. Harrisburg, PA: Military Service Publishing Co., 1941. CARL 355.22 J72b. Written in rough prose , this World War II era document explains the

  13. Intracellular calcium mobilization and phospholipid degradation in sphingosylphosphorylcholine-stimulated human airway epithelial cells.

    PubMed Central

    Orlati, S; Porcelli, A M; Hrelia, S; Lorenzini, A; Rugolo, M

    1998-01-01

    Extracellular sphingosylphosphorylcholine (SPC) caused a remarkable elevation in the intracellular Ca2+ concentration ([Ca2+]i) in immortalized human airway epithelial cells (CFNP9o-). An increase in total inositol phosphates formation was determined; however, the dose responses for [Ca2+]i elevation and inositol phosphates production were slightly different and, furthermore, PMA and pertussis toxin almost completely inhibited [Ca2+]i mobilization by SPC, whereas inositol phosphates production was only partially reduced. The possible direct interaction of SPC with Ca2+ channels of intracellular stores was determined by experiments with permeabilized cells, where SPC failed to evoke Ca2+ release, whereas lysophosphatidic acid was shown to be effective. The level of phosphatidic acid was increased by SPC only in the presence of AACOCF3, a specific inhibitor of phospholipase A2 (PLA2) and blocked by both pertussis toxin and R59022, an inhibitor of diacylglycerol kinase. R59022 enhanced diacylglycerol production by SPC and also significantly reduced [Ca2+]i mobilization. Only polyunsaturated diacylglycerol and phosphatidic acid were generated by SPC. Lastly, SPC caused stimulation of arachidonic acid release, indicating the involvement of PLA2. Taken together, these data suggest that, after SPC stimulation, phospholipase C-derived diacylglycerol is phosphorylated by a diacylglycerol kinase to phosphatidic acid, which is further hydrolysed by PLA2 activity to arachidonic and lysophosphatidic acids. We propose that lysophosphatidic acid might be the intracellular messenger able to release Ca2+ from internal stores. PMID:9729473

  14. Selective mobilization of saturated fatty acids in isolated adipocytes of hibernating 13-lined ground squirrels Ictidomys tridecemlineatus.

    PubMed

    Price, Edwin R; Armstrong, Christopher; Guglielmo, Christopher G; Staples, James F

    2013-01-01

    Fatty acids are not mobilized from adipocyte triacylglycerols uniformly but rather some are preferentially mobilized while others are preferentially retained. In many vertebrate species, the pattern of differential mobilization is determined by the physical and chemical properties of each fatty acid. Fatty acids with shorter chains and more double bonds tend to be more readily mobilized than others, a pattern observed both in whole-animal studies and in isolated adipocytes. Several hibernating species seem to break this pattern, however, and retain 18:2ω6 (linoleic acid) while mobilizing saturated fatty acids such as 18:0. We sought to confirm this pattern in adipocytes of a hibernator, the 13-lined ground squirrel Ictidomys tridecemlineatus, and to investigate mobilization patterns for the first time at hibernation temperature. We isolated adipocytes from summer active and winter torpid squirrels and incubated them with 1 μM norepinephrine at 4°C (7 h) and 37°C (90 min). We measured the proportion of each fatty acid in the adipose tissue and in the buffer at the end of incubation. Patterns of mobilization were similar in both seasons and incubation temperatures. Saturated fatty acids (18:0 and 16:0) were highly mobilized relative to the average, while some unsaturated fatty acids (notably, 18:1ω9 and 18:2ω6) were retained. We conclude that hibernators have unique mechanisms at the level of adipose tissue that preferentially mobilize saturated fatty acids. Additionally, we found that adipocytes from hibernating squirrels produced more glycerol than those from summer squirrels (regardless of temperature), indicating a higher lipolytic capacity in hibernating squirrels.

  15. Circulating nucleic acids: a new class of physiological mobile genetic elements.

    PubMed

    Mittra, Indraneel

    2015-01-01

    Mobile genetic elements play a major role in shaping biotic genomes and bringing about evolutionary transformations. Herein, a new class of mobile genetic elements is proposed in the form of circulating nucleic acids (CNAs) derived from the billions of cells that die in the body every day due to normal physiology and that act intra-corporeally. A recent study shows that CNAs can freely enter into healthy cells, integrate into their genomes by a unique mechanism and cause damage to their DNA. Being ubiquitous and continuously arising, CNA-induced DNA damage may be the underlying cause of ageing, ageing-related disabilities and the ultimate demise of the organism. Thus, DNA seems to act in the paradoxical roles of both preserver and destroyer of life. This new class of mobile genetic element may be relevant not only to multi-cellular organisms with established circulatory systems, but also to other multi-cellular organisms in which intra-corporeal mobility of nucleic acids may be mediated via the medium of extra-cellular fluid.

  16. Circulating nucleic acids: a new class of physiological mobile genetic elements

    PubMed Central

    Mittra, Indraneel

    2015-01-01

    Mobile genetic elements play a major role in shaping biotic genomes and bringing about evolutionary transformations. Herein, a new class of mobile genetic elements is proposed in the form of circulating nucleic acids (CNAs) derived from the billions of cells that die in the body every day due to normal physiology and that act intra-corporeally. A recent study shows that CNAs can freely enter into healthy cells, integrate into their genomes by a unique mechanism and cause damage to their DNA. Being ubiquitous and continuously arising, CNA-induced DNA damage may be the underlying cause of ageing, ageing-related disabilities and the ultimate demise of the organism. Thus, DNA seems to act in the paradoxical roles of both preserver and destroyer of life. This new class of mobile genetic element may be relevant not only to multi-cellular organisms with established circulatory systems, but also to other multi-cellular organisms in which intra-corporeal mobility of nucleic acids may be mediated via the medium of extra-cellular fluid. PMID:26664710

  17. Uniform fatty acid mobilization from anatomically distinct fat depots in the sable (Martes zibellina).

    PubMed

    Nieminen, Petteri; Mustonen, Anne-Mari

    2007-07-01

    The mobilization of fatty acids (FA) is a selective process in humans, rodents and the few previously studied carnivores. The FA composition of and mobilization from different fat depots reflect the functions of adipose tissues, e.g. in energy storage or insulation. Sixteen farm-raised sables (Martes zibellina), a terrestrial mustelid, were assigned into a fed control group or fasted for 4 days. The FA composition of the sable was relatively similar to other previously studied mustelids. The masses of the different fat depots decreased by 28-55% during fasting. The subcutaneous (sc) and intraabdominal (iab) fats had a uniform FA composition and the sable could mobilize both sc and iab FA. 18:3n-3, 18:4n-3 and 16:1n-7 were effectively mobilized, while long-chain saturated (SFA) and monounsaturated FA (MUFA) increased in proportion. Relative mobilization (RM) correlated inversely with the FA chain length and Delta9-desaturation increased RM of several MUFA compared to SFA. The results reinforce the hypothesis that the terrestrial sable can utilize sc and iab fat depots as energy reserves during nutritional scarcity. The natural history of the species is an important determinant of the FA composition and RM between anatomically different fat depots.

  18. Mobilization of Cr(VI) from chromite ore processing residue through acid treatment.

    PubMed

    Tinjum, James M; Benson, Craig H; Edil, Tuncer B

    2008-02-25

    Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH 7.6-8.1. Cr(VI) mobilized more slowly for larger particles, and the pH increased with time and increased more rapidly for smaller particles, suggesting that rate limitations occur in the solid phase. With H(2)SO(4), the pH stabilized at a higher value (8.8 for H(2)SO(4) vs. 8.0 for HNO(3)) and more rapidly (16 h vs. 30 h), and the differences in pH for different particle sizes were smaller. The acid neutralization capacity (ANC) of COPR is very large (8 mol HNO(3) per kg of dry COPR for a stable eluate pH of 7.5). Changes to the elemental and mineralogical composition and distribution in COPR particles after mixing with acid indicate that Cr(VI)-bearing solids dissolved. However, concentrations of Cr(VI) >2800 mg kg(-1) (>50% of the pre-treatment concentration) were still found after mixing with acid, regardless of the particle size, reaction time, or type of acid used. The residual Cr(VI) appears to be partially associated with poorly-ordered Fe and Al oxyhydroxides that precipitated in the interstitial areas of COPR particles. Remediation strategies that use HNO(3) or H(2)SO(4) to neutralize COPR or to maximize Cr(VI) in solution are likely to require extensive amounts of acid, may not mobilize all of the Cr(VI), and may require extended contact time, even under well-mixed conditions.

  19. A method to attenuate U(VI) mobility in acidic waste plumes using humic acids

    SciTech Connect

    Wan, J.; Dong, W.; Tokunaga, T.K.

    2011-02-01

    Acidic uranium (U) contaminated plumes have resulted from acid-extraction of plutonium during the Cold War and from U mining and milling operations. A sustainable method for in-situ immobilization of U under acidic conditions is not yet available. Here, we propose to use humic acids (HAs) for in-situ U immobilization in acidic waste plumes. Our laboratory batch experiments show that HA can adsorb onto aquifer sediments rapidly, strongly and practically irreversibly. Adding HA greatly enhanced U adsorption capacity to sediments at pH below 5.0. Our column experiments using historically contaminated sediments from the Savannah River Site under slow flow rates (120 and 12 m/y) show that desorption of U and HA were non-detectable over 100 pore-volumes of leaching with simulated acidic groundwaters. Upon HA-treatment, 99% of the contaminant [U] was immobilized at pH < 4.5, compared to 5% and 58% immobilized in the control columns at pH 3.5 and 4.5, respectively. These results demonstrated that HA-treatment is a promising in-situ remediation method for acidic U waste plumes. As a remediation reagent, HAs are resistant to biodegradation, cost effective, nontoxic, and easily introducible to the subsurface.

  20. Simultaneous Determination of Trigonelline, Caffeine, Chlorogenic Acid and Their Related Compounds in Instant Coffee Samples by HPLC Using an Acidic Mobile Phase Containing Octanesulfonate.

    PubMed

    Arai, Kana; Terashima, Hiroyuki; Aizawa, Sen-ichi; Taga, Atsushi; Yamamoto, Atsushi; Tsutsumiuchi, Kaname; Kodama, Shuji

    2015-01-01

    In order to analyze trigonelline, caffeine, chlorogenic acid, and their related compounds simultaneously, an HPLC method using an InertSustain C18 column and a mobile phase containing octanesulfonate as an ion-pairing reagent under an acidic condition was developed. The optimum mobile phase conditions were determined to be 0.1% phosphoric acid, 4 mM octanesulfonate, and 15% methanol at 35°C. Using the proposed method, trigonelline, nicotinic acid, caffeine, theophylline, chlorogenic acid, and caffeic acid in ten instant coffee samples were analyzed. These analytes except for theophylline were detected in all samples. An increase in the caffeine content in instant coffee samples tended to decrease in both trigonelline and chlorogenic acid contents, and the trigonelline content was found to be correlated well with the chlorogenic acid content (R(2) = 0.887).

  1. Site-Specific Characterization of d-Amino Acid Containing Peptide Epimers by Ion Mobility Spectrometry

    PubMed Central

    2013-01-01

    Traditionally, the d-amino acid containing peptide (DAACP) candidate can be discovered by observing the differences of biological activity and chromatographic retention time between the synthetic peptides and naturally occurring peptides. However, it is difficult to determine the exact position of d-amino acid in the DAACP candidates. Herein, we developed a novel site-specific strategy to rapidly and precisely localize d-amino acids in peptides by ion mobility spectrometry (IMS) analysis of mass spectrometry (MS)-generated epimeric fragment ions. Briefly, the d/l-peptide epimers were separated by online reversed-phase liquid chromatography and fragmented by collision-induced dissociation (CID), followed by IMS analysis. The epimeric fragment ions resulting from d/l-peptide epimers exhibit conformational differences, thus showing different mobilities in IMS. The arrival time shift between the epimeric fragment ions was used as criteria to localize the d-amino acid substitution. The utility of this strategy was demonstrated by analysis of peptide epimers with different molecular sizes, [d-Trp]-melanocyte-stimulating hormone, [d-Ala]-deltorphin, [d-Phe]-achatin-I, and their counterparts that contain all-l amino acids. Furthermore, the crustacean hyperglycemia hormones (CHHs, 8.5 kDa) were isolated from the American lobster Homarus americanus and identified by integration of MS-based bottom-up and top-down sequencing approaches. The IMS data acquired using our novel site-specific strategy localized the site of isomerization of l- to d-Phe at the third residue of the CHHs from the N-terminus. Collectively, this study demonstrates a new method for discovery of DAACPs using IMS technique with the ability to localize d-amino acid residues. PMID:24328107

  2. Combined effects of low-molecular-weight organic acids on mobilization of arsenic and lead from multi-contaminated soils.

    PubMed

    Onireti, Olaronke O; Lin, Chuxia; Qin, Junhao

    2017-03-01

    A batch experiment was conducted to examine the combined effects of three common low-molecular-weight organic acids (LMWOAs) on the mobilization of arsenic and lead in different types of multi-contaminated soils. The capacity of individual LMWOAs (at a same molar concentration) to mobilize soil-borne As and Pb varied significantly. The combination of the organic acids did not make a marked "additive" effect on the mobilization of the investigated three elements. An "antagonistic" effect on element mobilization was clear in the treatments involving oxalic acid for some soils. The acid strength of a LMWOA did not play an important role in controlling the mobilization of elements. While the mobilization of As and Pb was closely associated with the dissolution of soil-borne Fe, soil properties such as original soil pH, organic matter contents and the total amount of the element relative to the total Fe markedly complicated the mobility of that element. Aging led to continual consumption of proton introduced from addition of LMWOAs and consequently caused dramatic changes in solution-borne Fe, which in turn resulted in change in As and Pb in the soil solution though different elements behaved differently.

  3. Standard systems for measurement of pKs and ionic mobilities. 1. Univalent weak acids.

    PubMed

    Slampová, Andrea; Krivánková, Ludmila; Gebauer, Petr; Bocek, Petr

    2008-12-05

    Determination of pK values of weak bases and acids by CZE has already attracted big attention in current practice and proved to offer the advantage of being applicable for mixtures of analytes. The method is based on the measurement of mobility curves plotting the effective mobility vs. the pH of the background electrolyte, and following computer-assisted regression involving corrections for ionic strength and temperature. To cover the necessary range of pH for a given case, both buffering weak acids and bases are used in one set of measurements, which requires implementing computations of individual ionic strength corrections for each pH value. It is also well known that some components of frequently used background electrolytes may interact with the analytes measured, on forming associates or complexes. This obviously deteriorates the reliability of the resulting data. This contribution brings a rational approach to this problem and establishes a standard system of anionic buffers for measurements of pKs and mobilities of weak acids, where the only counter cation present (besides H(+)) is Na(+). In this way, the risk of formation of complexes or associates of analytes with counter ions is strongly reduced. Moreover, the standard system of anionic buffers is selected in such a way that it provides, for an entire set of measurements, constant and accurately known ionic strength and the operational conditions are selected so that they provide constant Joule heating. Due to these precautions only one correction for ionic strength and temperature is needed for the obtained set of experimental data. This considerably facilitates their evaluation and regression analysis as the corrections need not be implemented in the computation software. The reliability and the advantages of the proposed system are well documented by experiments, where the known problematic group of phenol derivatives was measured with high accuracy and without any notice of anomalous behaviour.

  4. Acidic deposition, cation mobilization, and biochemical indicators of stress in healthy red spruce

    USGS Publications Warehouse

    Shortle, W.C.; Smith, K.T.; Minocha, R.; Lawrence, G.B.; David, M.B.

    1997-01-01

    Dendrochemical and biochemical markers link stress in apparently healthy red spruce trees (Picea rubens) to acidic deposition. Acidic deposition to spruce forests of the northeastern USA increased sharply during the 1960s. Previous reports related visible damage of trees at high elevations to root and soil processes. In this report, dendrochemical and foliar biochemical markers indicate perturbations in biological processes in healthy red spruce trees across the northeastern USA. Previous research on the dendrochemistry of red spruce stemwood indicated that under uniform environmental conditions, stemwood concentrations of Ca and Mg decreased with increasing radial distance from the pith. For nine forest locations, frequency analysis shows that 28 and 52% of samples of red spruce stemwood formed in the 1960s are enriched in Ca and Mg, respectively, relative to wood formed prior to and after the 1960s. This enrichment in trees throughout the northeastern USA may be interpretable as a signal of increased availability of essential cations in forest soils. Such a temporary increase in the availability of Ca and Mg could be caused by cation mobilization, a consequence of increased acidic deposition. During cation mobilization, essential Ca and Mg as well as potentially harmful Al become more available for interaction with binding sites in the soil and absorbing roots. As conditions which favor cation mobilization continue, Ca and Mg can be leached or displaced from the soil. A measure of the interaction between Ca and Al is the Al/Ca binding ratio (molar charge ratio of exchangeable Al to exchangeable Ca). As the Al/Ca binding ratio in the root zone increased from 0.3 to 1.9, the foliar concentration of the biochemical stress marker putrescine also increased from 45 to 145 nm g-1. The correlation of the putrescine concentration to the Al/Ca binding ratio (adj. r2 = 0.68, P < 0.027) suggests that foliar stress may be linked to soil chemistry.

  5. Selective fatty acid mobilization from adipose tissues of the pheasant (Phasianus colchicus mongolicus) during food deprivation.

    PubMed

    Mustonen, Anne-Mari; Käkelä, Reijo; Asikainen, Juha; Nieminen, Petteri

    2009-01-01

    Avian response to fasting has been examined intensively in penguins (Aptenodytes spp.) adapted to long-term food deprivation but less in species experiencing shorter fasts. Thus, the selectivity in (i) incorporating different fatty acids (FA) from diet into total lipids of white adipose tissue (WAT) and liver and (ii) mobilizing FA from these tissues was examined in pheasants Phasianus colchicus mongolicus fed or fasted for 4 d. Dietary FA were selectively incorporated into intra-abdominal and subcutaneous WAT having a similar composition. The WAT lipids contained higher proportions of saturated and monounsaturated FA and less polyunsaturated FA (PUFA) than the dietary profile. However, the isomers of 20:1 and 22:1 were incorporated inefficiently into the WAT lipids. The essential C18 PUFA precursors having smaller percentages in the pheasant tissues than in the diet were likely converted into longer-chain derivatives probably utilized to a great extent for structural lipids of muscles and organs. During food deprivation, the pheasants preferentially utilized 16:1n-7, 18:3n-3, 18:1n-9, and 16:0 but preserved long-chain saturated and unsaturated FA. Mobilization was more efficient for shorter-chain FA and increased with Delta9-desaturation. The hepatic FA profile was resistant to the 4-d period of food deprivation. The results demonstrate that the incorporation of FA into WAT and their mobilization from lipid stores are selective not only in mammals but also in birds.

  6. Acidic deposition, cation mobilization, and biochemical indicators of stress in healthy red spruce

    SciTech Connect

    Shortle, W.C.; Smith, K.T.; Minocha, R.

    1997-05-01

    Dendrochemical and biochemical markers link stress in apparently healthy red spruce trees (Picea rubens) to acidic deposition. Previous reports related visible damage of trees at high elevations to root and soil processes. In this report, dendrochemical and foliar biochemical markers indicate perturbations in biological processes in healthy red spruce trees across the northeastern USA. Previous research on the dendrochemistry of red spruce stemwood indicated that under uniform environmental conditions, stemwood concentrations of Ca and Mg decreased with increasing radial distance from the pith. For nine forest locations, frequency analysis shows that 28 and 52% of samples of red spruce stemwood formed in the 1960s are enriched in Ca and Mg, respectively, relative to wood formed prior to and after the 1960s. This enrichment in trees throughout the northeastern USA may be interpretable as a signal of increased availability of essential cations in forest soils. Such a temporary increase in the availability of Ca and Mg could be caused by cation mobilization, a consequence of increased acidic deposition. During cation mobilization, essential and Ca and Mg as well as potentially harmful Al become more available for interaction with binding sites in the soil and absorbing roots. As conditions which favor cation mobilization continue, Ca and Mg can be leached or displaced from the soil. A measure of the interaction between Ca and Al is the Al/Ca binding ratio (molar charge ratio of exchangeable Al to exchangeable Ca). As the Al/Ca binding ratio in the root zone increased from 0.3 to 1.9, the foliar concentration of the biochemical stress marker putrescine also increased form 45 to 145 nm g{sup {minus}1}. The correlation of the putrescine concentration to the Al/Ca binding ratio (adj. r{sup 2} = 0.68, P <0.027) suggests that foliar stress may be linked to soil chemistry. 32 refs., 2 figs., 1 tab.

  7. Chemical speciation and mobilization of copper and zinc in naturally contaminated mine soils with citric and tartaric acids.

    PubMed

    Pérez-Esteban, Javier; Escolástico, Consuelo; Moliner, Ana; Masaguer, Alberto

    2013-01-01

    A one-step extraction procedure and a leaching column experiment were performed to assess the effects of citric and tartaric acids on Cu and Zn mobilization in naturally contaminated mine soils to facilitate assisted phytoextraction. A speciation modeling of the soil solution and the metal fractionation of soils were performed to elucidate the chemical processes that affected metal desorption by organic acids. Different extracting solutions were prepared, all of which contained 0.01 M KNO(3) and different concentrations of organic acids: control without organic acids, 0.5 mM citric, 0.5 mM tartaric, 10 mM citric, 10 mM tartaric, and 5 mM citric +5 mM tartaric. The results of the extraction procedure showed that higher concentrations of organic acids increased metal desorption, and citric acid was more effective at facilitating metal desorption than tartaric acid. Metal desorption was mainly influenced by the decreasing pH and the dissolution of Fe and Mn oxides, not by the formation of soluble metal-organic complexes as was predicted by the speciation modeling. The results of the column study reported that low concentrations of organic acids did not significantly increase metal mobilization and that higher doses were also not able to mobilize Zn. However, 5-10 mM citric acid significantly promoted Cu mobilization (from 1 mg kg(-1) in the control to 42 mg kg(-1) with 10 mM citric acid) and reduced the exchangeable (from 21 to 3 mg kg(-1)) and the Fe and Mn oxides (from 443 to 277 mg kg(-1)) fractions. Citric acid could efficiently facilitate assisted phytoextraction techniques.

  8. Use of microfocused X-ray techniques to investigate the mobilization of arsenic by oxalic acid

    NASA Astrophysics Data System (ADS)

    Wovkulich, Karen; Mailloux, Brian J.; Bostick, Benjamin C.; Dong, Hailiang; Bishop, Michael E.; Chillrud, Steven N.

    2012-08-01

    Improved linkages between aqueous phase transport and solid-phase reactions are needed to better predict and model transport of contaminants through the subsurface. Here we develop and apply a new method for measuring As mobilization in situ within soil columns that utilizes synchrotron-based X-ray fluorescence. By performing these measurements in situ during column transport experiments, we simultaneously monitor grain-scale solid phase reactions and column-scale transport. Arsenic may be effectively mobilized by oxalic acid but the geochemical and mineralogical factors that influence the rate and extent of mobilization are not well understood. Column experiments (˜4 cm long × 0.635 cm ID) using As contaminated sediments from the Vineland Chemical Company Superfund site were performed on the laboratory bench as well as in the synchrotron beamline. Microfocused synchrotron X-ray fluorescence (μSXRF) maps for As and Fe were collected at the same location in the columns (<1 mm2) before and during treatment with 10 mM oxalic acid. The fraction of As and Fe removed by oxalic acid treatment was calculated from the change in flux-normalized counts for each pixel in the map images, and these data were used to calculate kinetic parameters over the studied area. Between 79% and 83% of the As was removed from the sediments by the oxalic acid treatment based on μSXRF data; these removal percentages agreed well with laboratory data based on column effluent (88-95%). Considerably less Fe was removed by oxalic acid treatment, 14-25% based on μSXRF counts, which is somewhat higher than the 7-9% calculated from laboratory column effluent concentrations. Microfocused X-ray absorption near edge spectroscopy (μXANES) on a subset of points indicates most of the Fe was oxidized and present as a mixture of goethite, hematite, and ferrihydrite on sand grain coatings. Treatment with oxalic acid led to subtle shifts in Fe (III) species following oxalic acid treatment, either removing

  9. Use of Microfocused X-ray Techniques to Investigate the Mobilization of As by Oxalic Acid

    PubMed Central

    Wovkulich, Karen; Mailloux, Brian J.; Bostick, Benjamin C.; Dong, Hailiang; Bishop, Michael E.; Chillrud, Steven N.

    2012-01-01

    Improved linkages between aqueous phase transport and solid-phase reactions are needed to better predict and model transport of contaminants through the subsurface. Here we develop and apply a new method for measuring As mobilization in situ within soil columns that utilizes synchrotron-based X-ray fluorescence. By performing these measurements in situ during column transport experiments, we simultaneously monitor grain-scale solid phase reactions and column-scale transport. Arsenic may be effectively mobilized by oxalic acid but the geochemical and mineralogical factors that influence the rate and extent of mobilization are not well understood. Column experiments (~4 cm long × 0.635 cm ID) using As contaminated sediments from the Vineland Chemical Company Superfund site were performed on the laboratory bench as well as in the synchrotron beamline. Microfocused synchrotron X-ray fluorescence (μSXRF) maps for As and Fe were collected at the same location in the columns (<1 mm2) before and during treatment with 10 mM oxalic acid. The fraction of As and Fe removed by oxalic acid treatment was calculated from the change in flux-normalized counts for each pixel in the map images, and these data were used to calculate kinetic parameters over the studied area. Between 79% and 83% of the As was removed from the sediments by the oxalic acid treatment based on μSXRF data; these removal percentages agreed well with laboratory data based on column effluent (88–95%). Considerably less Fe was removed by oxalic acid treatment, 14–25% based on μSXRF counts, which is somewhat higher than the 7–9% calculated from laboratory column effluent concentrations. Microfocused X-ray absorption near edge spectroscopy (μXANES) on a subset of points indicates most of the Fe was oxidized and present as a mixture of goethite, hematite, and ferrihydrite on sand grain coatings. Treatment with oxalic acid led to subtle shifts in Fe (III) species following oxalic acid treatment, either

  10. Brønsted Acid Catalysis-Structural Preferences and Mobility in Imine/Phosphoric Acid Complexes.

    PubMed

    Greindl, Julian; Hioe, Johnny; Sorgenfrei, Nils; Morana, Fabio; Gschwind, Ruth M

    2016-12-14

    Despite the huge success of enantioselective Brønsted acid catalysis, experimental data about structures and activation modes of substrate/catalyst complexes in solution are very rare. Here, for the first time, detailed insights into the structures of imine/Brønsted acid catalyst complexes are presented on the basis of NMR data and underpinned by theoretical calculations. The chiral Brønsted acid catalyst R-TRIP (3,3'-bis(2,4,6-triisopropylphenyl)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate) was investigated together with six aromatic imines. For each investigated system, an E-imine/R-TRIP complex and a Z-imine/R-TRIP complex were observed. Each of these complexes consists of two structures, which are in fast exchange on the NMR time scale; i.e., overall four structures were found. Both identified E-imine/R-TRIP structures feature a strong hydrogen bond but differ in the orientation of the imine relative to the catalyst. The exchange occurs by tilting the imine inside the complex and thereby switching the oxygen that constitutes the hydrogen bond. A similar situation is observed for all investigated Z-imine/R-TRIP complexes. Here, an additional exchange pathway is opened via rotation of the imine. For all investigated imine/R-TRIP complexes, the four core structures are highly preserved. Thus, these core structures are independent of electron density and substituent modulations of the aromatic imines. Overall, this study reveals that the absolute structural space of binary imine/TRIP complexes is large and the variations of the four core structures are small. The high mobility is supposed to promote reactivity, while the preservation of the core structures in conjunction with extensive π-π and CH-π interactions leads to high enantioselectivities and tolerance of different substrates.

  11. Brønsted Acid Catalysis—Structural Preferences and Mobility in Imine/Phosphoric Acid Complexes

    PubMed Central

    2016-01-01

    Despite the huge success of enantioselective Brønsted acid catalysis, experimental data about structures and activation modes of substrate/catalyst complexes in solution are very rare. Here, for the first time, detailed insights into the structures of imine/Brønsted acid catalyst complexes are presented on the basis of NMR data and underpinned by theoretical calculations. The chiral Brønsted acid catalyst R-TRIP (3,3′-bis(2,4,6-triisopropylphenyl)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate) was investigated together with six aromatic imines. For each investigated system, an E-imine/R-TRIP complex and a Z-imine/R-TRIP complex were observed. Each of these complexes consists of two structures, which are in fast exchange on the NMR time scale; i.e., overall four structures were found. Both identified E-imine/R-TRIP structures feature a strong hydrogen bond but differ in the orientation of the imine relative to the catalyst. The exchange occurs by tilting the imine inside the complex and thereby switching the oxygen that constitutes the hydrogen bond. A similar situation is observed for all investigated Z-imine/R-TRIP complexes. Here, an additional exchange pathway is opened via rotation of the imine. For all investigated imine/R-TRIP complexes, the four core structures are highly preserved. Thus, these core structures are independent of electron density and substituent modulations of the aromatic imines. Overall, this study reveals that the absolute structural space of binary imine/TRIP complexes is large and the variations of the four core structures are small. The high mobility is supposed to promote reactivity, while the preservation of the core structures in conjunction with extensive π–π and CH−π interactions leads to high enantioselectivities and tolerance of different substrates. PMID:27960345

  12. Linking molecular models with ion mobility experiments. Illustration with a rigid nucleic acid structure

    PubMed Central

    D'Atri, Valentina; Porrini, Massimiliano; Rosu, Frédéric; Gabelica, Valérie

    2015-01-01

    Ion mobility spectrometry experiments allow the mass spectrometrist to determine an ion's rotationally averaged collision cross section ΩEXP. Molecular modelling is used to visualize what ion three-dimensional structure(s) is(are) compatible with the experiment. The collision cross sections of candidate molecular models have to be calculated, and the resulting ΩCALC are compared with the experimental data. Researchers who want to apply this strategy to a new type of molecule face many questions: (1) What experimental error is associated with ΩEXP determination, and how to estimate it (in particular when using a calibration for traveling wave ion guides)? (2) How to generate plausible 3D models in the gas phase? (3) Different collision cross section calculation models exist, which have been developed for other analytes than mine. Which one(s) can I apply to my systems? To apply ion mobility spectrometry to nucleic acid structural characterization, we explored each of these questions using a rigid structure which we know is preserved in the gas phase: the tetramolecular G-quadruplex [dTGGGGT]4, and we will present these detailed investigation in this tutorial. © 2015 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons Ltd. PMID:26259654

  13. Antimitogenic effect of Larrea divaricata Cav.: participation in arachidonate metabolism.

    PubMed

    Anesini, C; Genaro, A; Cremaschi, G; Sterin Borda, L; Borda, E

    1999-02-01

    Aqueous extracts of the leaves of Larrea divaricata Cav. exert antimitogenic effects on tumor cells (BW 5147 murine immature T-lymphoma) and normal, stimulated lymphocytes. The effective concentration was four times smaller in the case of tumor cells than in the case of normal, stimulated lymphocytes. Inhibitor studies of arachidonate pathway suggest that the proliferative effect of the extract is due to the activation of lipoxygenase metabolism, while the inhibitory action could be a direct effect.

  14. Imitation of artificial membrane system via mobile phases with Tween-80 and cholic acid in biopartitioning micellar chromatography.

    PubMed

    Rukhadze, Marina D; Sebiskveradze, Maya V; Akhalkatsi, Tsaro G; Makharadze, Teona G

    2006-08-01

    The chromatographic behaviour of compounds of biomedical significance was studied using micellar mobile phases modified with polyoxyethylene (20) sorbitan monooleate (Tween-80). The influence of the surfactant within the 0.75-4% concentration range on the retention factor of model compounds was investigated. The biological surfactant cholic acid was introduced into the mobile phases in order to approach to the structure of natural membranes, viz. erythrocyte and cytoplasmatic membranes. It was found that curves of dependence of retention factor vs concentration of Tween-80 in the absence and presence of cholic acid in the mobile phase considerably diverge with one another, especially in the 2-3% concentration range of Tween-80 using C18-type support. Increasing the concentration of Tween-80 resulted in the increase of retention factors using phenyl-coated stationary phase.

  15. Analysis of carbon functional groups in mobile humic acid and recalcitrant calcium humate extracted from eight US soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solid state 13C nuclear magnetic resonance (NMR) spectroscopy is a common tool to study the structure of soil humic fractions; however, knowledge regarding carbon structural relationships in humic fractions is limited. In this study, mobile humic acid (MHA) and recalcitrant calcium humate (CaHA) fr...

  16. Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

    NASA Astrophysics Data System (ADS)

    Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

    2012-12-01

    Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic

  17. Separation optimization in reversed-phase liquid chromatography by using alkanol additives in the mobile phase: application to amino acids.

    PubMed

    Pappa-Louisi, A; Agrafiotou, P; Georgiadis, I

    2011-09-30

    In an effort to enhance complex mixture separations by using small amounts of a homologous series of alkanols as additives in the mobile phases, it was proposed an optimization algorithm based on a sixth-parameter retention model. This model considers simultaneously the contents of the main organic modifier and of the alkanol additive in the mobile phase as well as of the number of alkyl chain of the additive. This model is in fact a modification of a previously one derived in a recently published paper for the retention description of a mixture of purely hydrophobic alkylbenzenes under isocratic conditions with mobile phases containing alkanol additives. The effectiveness of the new retention model as well as the optimization algorithm was successfully applied to the separation of ten o-phthalaldehyde (OPA) derivatives of amino acids. Indeed, the new retention model exhibited an excellent prediction performance since the obtained overall predictive error between calculated and experimental times was only 2.8% for all isocratic runs by using a variety of mobile phase compositions containing any alkanol homologue even different than those used in the starting/fitting experiments. Moreover, a perfect resolution of the above amino acid mixture was achieved within only 7.4 min in the chromatogram recorded using the optimal mobile phase determined by means of the simple optimization algorithm proposed in this study.

  18. Element mobility and partitioning along a soil acidity gradient in central Ontario forests, Canada.

    PubMed

    Watmough, Shaun A

    2008-10-01

    The potential environmental risk posed by metals in forest soils is typically evaluated by modeling metal mobility using soil-solution partitioning coefficients (K(d)), although such information is generally restricted to a few well-studied metals. Soil-solution partitioning coefficients were determined for 17 mineral elements (Al, As, Be, Ba, Ca, Cr, Cu, Fe, Ga, K, Li, Mg, Rb, Sr, Tl, U and V) in A-horizon (0-5 cm) soil at 46 forested sites that border the Precambrian Shield in central Ontario, where soil pH(aq) varied from 3.9 to 8.1. Sites were dominated by mature sugar maple (Acer saccharum Marsh.), white birch (Betula papyrifera Marsh.), balsam fir (Abies balsamea (L.) Mill.) or white pine (Pinus strobus L.). Log K(d) values for all elements could be predicted by empirical linear regression with soil pH (r(2) = 0.17-0.77) independent of forest type, although this relationship was greatly affected by positive relationships between acid-extractable metal concentration and pH(aq) for 13 of the 17 elements. Elements that exhibited strong or moderate (r(2) > 0.29; p < 0.001) relationships with soil pH(aq) in soil water extracts include Al, Ba, Fe, Ga, K, Li, Rb, Tl, V (negative) and Ca (positive). Elemental partitioning in mineral soil was independent of forest type; tree species differed in their response to chemical differences in mineral soil. For example, Rb, Ba, and Sr concentrations in foliage of sugar maple and white birch significantly increased with increasing soil acidity, whereas Rb, Ba, and Sr concentrations in balsam fir and white pine foliage exhibited no response to soil pH(aq). While K(d) values can provide useful information on the potential mobility and bioavailability of mineral elements in forest soils, care must be used when interpreting the relative contribution of solid and aqueous phases to this relationship and the differing responses of vegetation in elemental cycling in forests must also be considered.

  19. Affinity Capillary Electrophoresis for Selective Control of Electrophoretic Mobility of Sialic Acid Using Lanthanide-Hexadentate Macrocyclic Polyazacarboxylate Complexes.

    PubMed

    Goto, Daiki; Ouchi, Kazuki; Shibukawa, Masami; Saito, Shingo

    2015-01-01

    It is difficult to control the electrophoretic mobility in order to obtain high resolution among saccharides in complex samples. We report herein on a new affinity capillary electrophoresis (ACE) method for an anionic monosaccharide, N-acetylneuraminic acid (Neu5Ac), which is important in terms of pathological diagnosis, using lanthanide-hexadentate macrocyclic polyazacarboxylate complexes (Ln-NOTA) as affinity reagents. It was shown that Ln-NOTA complexes increased the anionic mobility of Neu5Ac by approximately 40% through selective complexation with Neu5Ac. The extent of change in the mobility strongly depended on the type of central metal ion of Ln-NOTA. The stability constant (K) of Lu-NOTA with Neu5Ac was determined by ACE to be log Kb = 3.62 ± 0.04, which is the highest value among artificial receptors for Neu5Ac reported so far. Using this ACE, the Neu5Ac content in a glycoprotein sample, α1-acid glycoprotein (AGP), was determined after acid hydrolysis. Complete separation between Neu5Ac and hydrolysis products was successful by controlling the mobility to determine the concentration of Neu5Ac.

  20. Interactive computer-assisted instruction in acid-base physiology for mobile computer platforms.

    PubMed

    Longmuir, Kenneth J

    2014-03-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ∼20 screens of information, on the subjects of the CO2-bicarbonate buffer system, other body buffer systems, and acid-base disorders. Five clinical case modules were also developed. For the learning modules, the interactive, active learning activities were primarily step-by-step learner control of explanations of complex physiological concepts, usually presented graphically. For the clinical cases, the active learning activities were primarily question-and-answer exercises that related clinical findings to the relevant basic science concepts. The student response was remarkably positive, with the interactive, active learning aspect of the instruction cited as the most important feature. Also, students cited the self-paced instruction, extensive use of interactive graphics, and side-by-side presentation of text and graphics as positive features. Most students reported that it took less time to study the subject matter with this online instruction compared with subject matter presented in the lecture hall. However, the approach to learning was highly examination driven, with most students delaying the study of the subject matter until a few days before the scheduled examination. Wider implementation of active learning computer-assisted instruction will require that instructors present subject matter interactively, that students fully embrace the responsibilities of independent learning, and that institutional administrations measure instructional effort by criteria other than scheduled hours of instruction.

  1. Mobility and Oxidation of Adsorbed CO on Shape-Controlled Pt Nanoparticles in Acidic Medium.

    PubMed

    Farias, Manuel J S; Busó-Rogero, Carlos; Vidal-Iglesias, Francisco J; Solla-Gullón, José; Camara, Giuseppe A; Feliu, Juan M

    2017-01-31

    The knowledge about how CO occupies and detaches from specific surface sites on well-structured Pt surfaces provides outstanding information on both dynamics/mobility of COads and oxidation of this molecule under electrochemical conditions. This work reports how the potentiostatic growth of different coverage CO adlayers evolves with time on both cubic and octahedral Pt nanoparticles in acidic medium. Data suggest that during the growth of the CO adlayer, COads molecules slightly shift toward low coordination sites only on octahedral Pt nanoparticles, so that these undercoordinated sites are the first filled on octahedral Pt nanoparticles. Conversely, on cubic Pt nanoparticles, adsorbed CO behaves as an immobile species, and low coordinated sites as well as (100) terraces are apparently filled uniformly and simultaneously. However, once the adlayer is complete, irrespectively of whether the CO is oxidized in a single step or in a sequence of different potential steps, results suggest that COads behaves as an immobile species during its oxidation on both octahedral and cubic Pt nanoparticles.

  2. Structural Elucidation of cis/trans Dicaffeoylquinic Acid Photoisomerization Using Ion Mobility Spectrometry-Mass Spectrometry.

    PubMed

    Zheng, Xueyun; Renslow, Ryan S; Makola, Mpho M; Webb, Ian K; Deng, Liulin; Thomas, Dennis G; Govind, Niranjan; Ibrahim, Yehia M; Kabanda, Mwadham M; Dubery, Ian A; Heyman, Heino M; Smith, Richard D; Madala, Ntakadzeni E; Baker, Erin S

    2017-04-06

    Due to the recently uncovered health benefits and anti-HIV activities of dicaffeoylquinic acids (diCQAs), understanding their structures and functions is of great interest for drug discovery efforts. DiCQAs are analytically challenging to identify and quantify since they commonly exist as a diverse mixture of positional and geometric (cis/trans) isomers. In this work, we utilized ion mobility spectrometry coupled with mass spectrometry to separate the various isomers before and after UV irradiation. The experimental collision cross sections were then compared with theoretical structures to differentiate and identify the diCQA isomers. Our analyses found that naturally the diCQAs existed predominantly as trans/trans isomers, but after 3 h of UV irradiation, cis/cis, cis/trans, trans/cis, and trans/trans isomers were all present in the mixture. This is the first report of successful differentiation of cis/trans diCQA isomers individually, which shows the great promise of IMS coupled with theoretical calculations for determining the structure and activity relationships of different isomers in drug discovery studies.

  3. Mobilization of lead by esters of meso-2,3-dimercaptosuccinic acid

    SciTech Connect

    Singh, P.K.; Jones, M.M.; Xu, Z.; Gale, G.R.; Smith, A.B.; Atkins, L.M. )

    1989-01-01

    An examination was made of the relative efficacies of 2,3-dimercapto-1-propanol (BAL) and three diesters (CH(SH)COOR)2; DMDMS, R = CH3; DEDMS, R = C2H5; and Di-PDMS, R = CH(CH3)2 of meso-2,3-dimercaptosuccinic acid (DMSA) in mobilizing freshly injected lead from mice. These diesters, like BAL, reduced the lead levels resulting from freshly injected lead in both the soft tissues (liver, kidneys, spleen, and brain) and the bone (tibia). After treatment with the dimethyl (DMDMS), the diethyl (DEDMS), and the diisopropyl (Di-PDMS) esters the lead content of each of the organs was significantly less than that present in the untreated controls. Each of the diesters reduced lead levels in the kidneys, liver, and spleen significantly below those levels found after BAL treatment. The action of the diesters in reducing brain lead levels was comparable to that of BAL. Di-PDMS was the most effective of these compounds and was significantly superior to BAL. Each of the esters was also significantly more effective than BAL in reducing the whole body level of lead.

  4. High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

    SciTech Connect

    Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng

    2015-01-26

    High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm{sup 2}/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

  5. Microbial mobilization of cesium from illite: Role of organic acids and siderophores

    NASA Astrophysics Data System (ADS)

    Hazotte, Alice; Peron, Olivier; Abdelouas, Abdesselam; Lebeau, Thierry

    2015-04-01

    Understanding the behavior of cesium (Cs) in soils and geological formations is interesting in the context of nuclear accidents and nuclear waste disposals. Indeed, this radionuclide with a 30-years half-life can contaminate crops and more generally the food chain. Cs with properties similar to potassium is known to be strongly accumulated in the clays of upper soil horizons. While excavation of contaminated soil cannot be feasible for the whole contaminated surfaces (huge volumes to be cleaned-up), in situ methods could provide a sustainable and low cost solution. Phytoextraction is one of a few solutions for in situ remediation of soils contaminated by trace elements and it preserves the quality of agricultural soils. However, many improvements are still needed to enhance phytoextraction effectiveness. The combination of bioaugmentation (soil inoculation with exogenous microorganisms) with phytoextraction is likely to increase the bioaccessibility of radionuclides and their accumulation in plants. The role of bacteria on soil-pollutants can be direct (direct metal complexation) and/or indirect (weathering of clays adsorbing Cs). This study aims to provide more specifically a mechanistic understanding of the bacterial mobilization of Cs from soil with the prospect of soil bioremediation. Bacterial metabolites of Pseudomonas fluorescens (ATCC 17400) were supplied to illite spiked with 0.1 and 1 mM of Cs. Purified siderophores including pyoverdine from P. fluorescens, or the whole metabolites from the bacterial culture supernatant were compared to low molecular weight organic acids (LMWOA) (citric and oxalic acids) at 0.04 mM, or synthetic chelants, i.e., acetohydroxamic acid (AHA) and desferrioxamine mesylate (DFOM) ranging from 50 µM up to 250 µM. The release of Cs and the structural alteration of illite (release of Al, Fe and Si) were monitored. When compared to the control, no release of Cs from illite was observed with LMWOA. On the contrary, a slight release

  6. Astrocyte arachidonate and palmitate uptake and metabolism is differentially modulated by dibutyryl-cAMP treatment.

    PubMed

    Seeger, D R; Murphy, C C; Murphy, E J

    2016-07-01

    Astrocytes play a vital role in brain lipid metabolism; however the impact of the phenotypic shift in astrocytes to a reactive state on arachidonic acid metabolism is unknown. Therefore, we determined the impact of dibutyryl-cAMP (dBcAMP) treatment on radiolabeled arachidonic acid ([1-(14)C]20:4n-6) and palmitic acid ([1-(14)C]16:0) uptake and metabolism in primary cultured murine cortical astrocytes. In dBcAMP treated astrocytes, total [1-(14)C]20:4n-6 uptake was increased 1.9-fold compared to control, while total [1-(14)C]16:0 uptake was unaffected. Gene expression of long-chain acyl-CoA synthetases (Acsl), acyl-CoA hydrolase (Acot7), fatty acid binding protein(s) (Fabp) and alpha-synuclein (Snca) were determined using qRT-PCR. dBcAMP treatment increased expression of Acsl3 (4.8-fold) and Acsl4 (1.3-fold), which preferentially use [1-(14)C]20:4n-6 and are highly expressed in astrocytes, consistent with the increase in [1-(14)C]20:4n-6 uptake. However, expression of Fabp5 and Fabp7 were significantly reduced by 25% and 45%, respectively. Acot7 (20%) was also reduced, suggesting dBcAMP treatment favors acyl-CoA formation. dBcAMP treatment enhanced [1-(14)C]20:4n-6 (2.2-fold) and [1-(14)C]16:0 (1.6-fold) esterification into total phospholipids, but the greater esterification of [1-(14)C]20:4n-6 is consistent with the observed uptake through increased Acsl, but not Fabp expression. Although total [1-(14)C]16:0 uptake was not affected, there was a dramatic decrease in [1-(14)C]16:0 in the free fatty acid pool as esterification into the phospholipid pool was increased, which is consistent with the increase in Acsl3 and Acsl4 expression. In summary, our data demonstrates that dBcAMP treatment increases [1-(14)C]20:4n-6 uptake in astrocytes and this increase appears to be due to increased expression of Acsl3 and Acsl4 coupled with a reduction in Acot7 expression.

  7. Fish oil supplementation maintains adequate plasma arachidonate in cats, but similar amounts of vegetable oils lead to dietary arachidonate deficiency from nutrient dilution.

    PubMed

    Angell, Rebecca J; McClure, Melena K; Bigley, Karen E; Bauer, John E

    2012-05-01

    Because fatty acid (FA) metabolism of cats is unique, effects of dietary fish and vegetable oil supplementation on plasma lipids, lipoproteins, lecithin/cholesterol acyl transferase activities, and plasma phospholipid and esterified cholesterol (EC) FAs were investigated. Cats were fed a commercial diet supplemented with 8 g oil/100 g diet for 4 weeks using either high-oleic-acid sunflower oil (diet H), Menhaden fish oil (diet M), or safflower oil (diet S). When supplemented, diet M contained sufficient arachidonate (AA), but diets H and S were deficient. We hypothesized that diet M would modify plasma lipid metabolism, increase FA long-chain n-3 (LCn-3) FA content but not deplete AA levels. Also, diet S would show linoleic acid (LA) accumulation without conversion to AA, and both vegetable oil supplements would dilute dietary AA content when fed to meet cats' energy needs. Plasma samples on weeks 0, 2, and 4 showed no alterations in total cholesterol or nonesterified FA concentrations. Unesterified cholesterol decreased and EC increased in all groups, whereas lecithin/cholesterol acyl transferase activities were unchanged. Diet M showed significant triacylglycerol lowering and decreased pre-β-lipoprotein cholesterol. Plasma phospholipid FA profiles revealed significant enrichment of 18:1n-9 with diet H, LA and 20:2n-6 with diet S, and FA LCn-3FA with diet M. Depletion of AA was observed with diets H and S but not with diet M. Diet M EC FA profiles revealed specificities for LA and 20:5n-3 but not 22:5n-3 or 22:6n-3. Oversupplementation of some commercial diets with vegetable oils causes AA depletion in young cats due to dietary dilution. Findings are consistent with the current recommendations for at least 0.2 g AA/kg diet and that fish oil supplements provide both preformed LCn-3 polyunsaturated FA and AA.

  8. Dietary n-6 PUFA deprivation downregulates arachidonate but upregulates docosahexaenoate metabolizing enzymes in rat brain

    PubMed Central

    Kim, Hyung-Wook; Rao, Jagadeesh S; Rapoport, Stanley I.; Igarashi, Miki

    2010-01-01

    Background Dietary n-3 polyunsaturated fatty acid (PUFA) deprivation increases expression of arachidonic acid (AA 20:4n-6)-selective cytosolic phospholipase A2 (cPLA2) IVA and cyclooxygenase (COX)-2 in rat brain, while decreasing expression of docosahexaenoic acid (DHA 22:6n-3)-selective calcium-independent iPLA2 VIA. Assuming that these enzyme changes represented brain homeostatic responses to deprivation, we hypothesized that dietary n-6 PUFA deprivation would produce changes in the opposite directions. Methods Brain expression of PUFA-metabolizing enzymes and their transcription factors was quantified in male rats fed an n-6 PUFA adequate or deficient diet for 15 weeks post-weaning. Results The deficient compared with adequate diet increased brain mRNA, protein and activity of iPLA2 VIA and 15-lipoxygenase (LOX), but decreased cPLA2 IVA and COX-2 expression. The brain protein level of the iPLA2 transcription factor SREBP-1 was elevated, while protein levels were decreased for AP-2α and NF-κB p65, cPLA2 and COX-2 transcription factors, respectively. Conclusions With dietary n-6 PUFA deprivation, rat brain PUFA metabolizing enzymes and some of their transcription factors change in a way that would homeostatically dampen reductions in brain n-6 PUFA concentrations and metabolism, while n-3 PUFA metabolizing enzyme expression is increased. The changes correspond to reported in vitro enzyme selectivities for AA compared with DHA. (198 words) PMID:21070866

  9. Collision Cross Sections for 20 Protonated Amino Acids: Fourier Transform Ion Cyclotron Resonance and Ion Mobility Results

    NASA Astrophysics Data System (ADS)

    Anupriya; Jones, Chad A.; Dearden, David V.

    2016-08-01

    We report relative dephasing cross sections for the 20 biogenic protonated amino acids measured using the cross sectional areas by Fourier transform ion cyclotron resonance (CRAFTI) technique at 1.9 keV in the laboratory reference frame, as well as momentum transfer cross sections for the same ions computed from Boltzmann-weighted structures determined using molecular mechanics. Cross sections generally increase with increasing molecular weight. Cross sections for aliphatic and aromatic protonated amino acids are larger than the average trend, suggesting these side chains do not fold efficiently. Sulfur-containing protonated amino acids have smaller than average cross sections, reflecting the mass of the S atom. Protonated amino acids that can internally hydrogen-bond have smaller than average cross sections, reflecting more extensive folding. The CRAFTI measurements correlate well with results from drift ion mobility (IMS) and traveling wave ion mobility (TWIMS) spectrometric measurements; CRAFTI results correlate with IMS values approximately as well as IMS and TWIMS values from independent measurements correlate with each other. Both CRAFTI and IMS results correlate well with the computed momentum transfer cross sections, suggesting both techniques provide accurate molecular structural information. Absolute values obtained using the various methods differ significantly; in the case of CRAFTI, this may be due to errors in measurements of collision gas pressure, measurement of excitation voltage, and/or dependence of cross sections on kinetic energy.

  10. Collision Cross Sections for 20 Protonated Amino Acids: Fourier Transform Ion Cyclotron Resonance and Ion Mobility Results.

    PubMed

    Anupriya; Jones, Chad A; Dearden, David V

    2016-08-01

    We report relative dephasing cross sections for the 20 biogenic protonated amino acids measured using the cross sectional areas by Fourier transform ion cyclotron resonance (CRAFTI) technique at 1.9 keV in the laboratory reference frame, as well as momentum transfer cross sections for the same ions computed from Boltzmann-weighted structures determined using molecular mechanics. Cross sections generally increase with increasing molecular weight. Cross sections for aliphatic and aromatic protonated amino acids are larger than the average trend, suggesting these side chains do not fold efficiently. Sulfur-containing protonated amino acids have smaller than average cross sections, reflecting the mass of the S atom. Protonated amino acids that can internally hydrogen-bond have smaller than average cross sections, reflecting more extensive folding. The CRAFTI measurements correlate well with results from drift ion mobility (IMS) and traveling wave ion mobility (TWIMS) spectrometric measurements; CRAFTI results correlate with IMS values approximately as well as IMS and TWIMS values from independent measurements correlate with each other. Both CRAFTI and IMS results correlate well with the computed momentum transfer cross sections, suggesting both techniques provide accurate molecular structural information. Absolute values obtained using the various methods differ significantly; in the case of CRAFTI, this may be due to errors in measurements of collision gas pressure, measurement of excitation voltage, and/or dependence of cross sections on kinetic energy. Graphical Abstract ᅟ.

  11. Comparison of arachidonate metabolism by alveolar macrophages from bighorn and domestic sheep.

    PubMed

    Silflow, R M; Foreyt, W J; Taylor, S M; Laegreid, W W; Liggitt, H D; Leid, R W

    1991-02-01

    We have defined the metabolites of arachidonic acid (AA) secreted by alveolar macrophages (AMs) of bighorn sheep and domestic sheep in response to three agents: calcium ionophore A23187, phorbol myristate acetate (PMA), and opsonized zymosan. Cells were labeled with [3H]AA prior to stimulation and 11 tritiated metabolites, including prostaglandins (PGs), thromboxanes (TXs), leukotrienes (LTs), and hydroxyeicosatetraenoic acids (HETEs), were detected and quantitated by high-performance liquid chromotography and radiometry. Zymosan stimulation resulted in the release of significantly elevated quantities (P less than 0.05), of LTB4, [5(S), 12(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid], 5-HETE, [5(S)-hydroxyeicosatetraenoic acid], and the nonenzymatic isomers of LTB4, [LTB I, 5(S),12(R)-6-trans-LTB4] and LTB II, [5(S), 12(S)-6-trans-LTB4], from domestic sheep AM when compared to bighorn sheep AM. Phorbol myristate acetate (PMA) stimulation released significantly elevated quantities (P less than 0.04), of TXB2, (thromboxane B2), HHT, [12(S)-12-hydroxy-5,8,10-heptadecaenoic acid], LTB I, LTB II, and 15-HETE, [15(S)-hydroxyeicosatetraenoic acid] from domestic sheep AMs when compared to bighorn sheep AMs. However, after A23187 challenge, only 15-HETE was significantly elevated (P less than 0.04) in domestic sheep AMs when compared to bighorn sheep AMs. These clear differences in AA metabolism of AMs obtained from bighorn and domestic sheep in response to three different agonists suggest not only different control mechanisms for lung metabolism of AA in the two species, but also suggest that differences in the metabolites released may lead to quite different regulation of lung defense mechanisms in the two sheep species.

  12. Effects of omega-3 fatty acids on regulatory T cells in hematologic neoplasms

    PubMed Central

    Betiati, Dayanne da Silva Borges; de Oliveira, Paula Fernanda; Camargo, Carolina de Quadros; Nunes, Everson Araújo; Trindade, Erasmo Benício Santos de Moraes

    2013-01-01

    The development of leukemia and lymphomas is related to the increase in inflammatory process modulators. These, in turn, have divergent actions on the neoplastic process. Populations of T cells have different roles in the neoplastic environment; while interferon-gamma positive T cells have antitumor activity, the FoxP3+interleukin-10 positive population present a pro-tumor activity. Simultaneously, the inflammatory process promotes the mobilization of fatty acids from the cell membrane to produce lipid mediators, which also participate of the inflammatory response. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) omega-3 fatty acids, when incorporated in the plasmatic membrane, decrease the arachidonic acid (AA) metabolism and the production of eicosanoids derived from it. Thus, an alternative family of lipid mediators are produced that are often less inflammatory than those produced from arachidonic acid. Fatty acids can also influence the production of peptide mediators such as cytokines, and the expression of transcription factors, which can determine the production patterns of eicosanoids and cytokines as well as cell differentiation. Due to these properties, the objective of this literature review was to investigate studies published over the last 15 years on the effects of using omega-3 fatty acids on inflammatory markers in leukemia and lymphomas. PMID:23741190

  13. D-2 dopamine receptor activation reduces free ( sup 3 H)arachidonate release induced by hypophysiotropic peptides in anterior pituitary cells

    SciTech Connect

    Canonico, P.L. )

    1989-09-01

    Dopamine reduces the stimulation of intracellular ({sup 3}H)arachidonate release produced by the two PRL-stimulating peptides angiotensin-II and TRH. This effect is concentration dependent and is mediated by stimulation of D-2 dopamine receptors. D-2 receptor agonists (bromocriptine, dihydroergocryptine, and dihydroergocristine) inhibit the release of fatty acid induced by angiotensin-II with a potency that parallels their ability to inhibit PRL release in vitro. Conversely, the selective D-2 receptor antagonist L-sulpiride completely prevents dopamine's effect, whereas SCH 23390 (a D-1 receptor antagonist) is ineffective. The inhibitory action of dopamine does not seem to be consequent to an action on the adenylate cyclase-cAMP system, as 8-bromo-cAMP (1 mM) does not affect either basal or dopamine-inhibited ({sup 3}H)arachidonate release. However, a 24-h pertussis toxin pretreatment significantly reduces the action of dopamine on fatty acid release. Collectively, these results suggest that D-2 dopamine receptor-mediated inhibition of intracellular ({sup 3}H)arachidonate release requires the action of a GTP-binding protein, but is not a consequence of an inhibitory action on cAMP levels.

  14. Feasibility of 19F-NMR for assessing the molecular mobility of flufenamic acid in solid dispersions.

    PubMed

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Toru

    2009-01-01

    The purpose of the present study was to clarify the feasibility of 19F-NMR for assessing the molecular mobility of flufenamic acid (FLF) in solid dispersions. Amorphous solid dispersions of FLF containing poly(vinylpyrrolidone) (PVP) or hydroxypropylmethylcellulose (HPMC) were prepared by melting and rapid cooling. Spin-lattice relaxation times (T1 and T(1rho)) of FLF fluorine atoms in the solid dispersions were determined at various temperatures (-20 to 150 degrees C). Correlation time (tauc), which is a measure of rotational molecular mobility, was calculated from the observed T1 or T1rho value and that of the T1 or T1rho minimum, assuming that the relaxation mechanism of spin-lattice relaxation of FLF fluorine atoms does not change with temperature. The tauc value for solid dispersions containing 20% PVP was 2-3 times longer than that for solid dispersions containing 20% HPMC at 50 degrees C, indicating that the molecular mobility of FLF in solid dispersions containing 20% PVP was lower than that in solid dispersions containing 20% HPMC. The amount of amorphous FLF remaining in the solid dispersions stored at 60 degrees C was successfully estimated by analyzing the solid echo signals of FLF fluorine atoms, and it was possible to follow the overall crystallization of amorphous FLF in the solid dispersions. The solid dispersion containing 20% PVP was more stable than that containing 20% HPMC. The difference in stability between solid dispersions containing PVP and HPMC is considered due to the difference in molecular mobility as determined by tauc. The molecular mobility determined by 19F-NMR seems to be a useful measure for assessing the stability of drugs containing fluorine atoms in amorphous solid dispersions.

  15. Carboxylic Acid Ionophores as Probes of the Role of Calcium in Biological Systems

    NASA Technical Reports Server (NTRS)

    Reed, P. W.

    1983-01-01

    The biological effects of calcium ionophores are described, focusing on arachidonic acid oxygenation, and the formation of a number of oxygenated metabolites of arachidonic acid. These metabolites are involved in a number of bodily functions, and their production may be regulated by calcium.

  16. Structures, Hydration, and Electrical Mobilities of Bisulfate Ion-Sulfuric Acid-Ammonia/Dimethylamine Clusters: A Computational Study.

    PubMed

    Tsona, Narcisse T; Henschel, Henning; Bork, Nicolai; Loukonen, Ville; Vehkamäki, Hanna

    2015-09-17

    Despite the well-established role of small molecular clusters in the very first steps of atmospheric particle formation, their thermochemical data are still not completely available due to limitation of the experimental techniques to treat such small clusters. We have investigated the structures and the thermochemistry of stepwise hydration of clusters containing one bisulfate ion, sulfuric acid, base (ammonia or dimethylamine), and water molecules using quantum chemical methods. We found that water facilitates proton transfer from sulfuric acid or the bisulfate ion to the base or water molecules, and depending on the hydration level, the sulfate ion was formed in most of the base-containing clusters. The calculated hydration energies indicate that water binds more strongly to ammonia-containing clusters than to dimethylamine-containing and base-free clusters, which results in a wider hydrate distribution for ammonia-containing clusters. The electrical mobilities of all clusters were calculated using a particle dynamics model. The results indicate that the effect of humidity is negligible on the electrical mobilities of molecular clusters formed in the very first steps of atmospheric particle formation. The combination of the results of this study with those previously published on the hydration of neutral clusters by our group provides a comprehensive set of thermochemical data on neutral and negatively charged clusters containing sulfuric acid, ammonia, or dimethylamine.

  17. Ferritin couples iron and fatty acid metabolism.

    PubMed

    Bu, Weiming; Liu, Renyu; Cheung-Lau, Jasmina C; Dmochowski, Ivan J; Loll, Patrick J; Eckenhoff, Roderic G

    2012-06-01

    A physiological relationship between iron, oxidative injury, and fatty acid metabolism exists, but transduction mechanisms are unclear. We propose that the iron storage protein ferritin contains fatty acid binding sites whose occupancy modulates iron uptake and release. Using isothermal microcalorimetry, we found that arachidonic acid binds ferritin specifically and with 60 μM affinity. Arachidonate binding by ferritin enhanced iron mineralization, decreased iron release, and protected the fatty acid from oxidation. Cocrystals of arachidonic acid and horse spleen apoferritin diffracted to 2.18 Å and revealed specific binding to the 2-fold intersubunit pocket. This pocket shields most of the fatty acid and its double bonds from solvent but allows the arachidonate tail to project well into the ferrihydrite mineralization site on the ferritin L-subunit, a structural feature that we implicate in the effects on mineralization by demonstrating that the much shorter saturated fatty acid, caprylate, has no significant effects on mineralization. These combined effects of arachidonate binding by ferritin are expected to lower both intracellular free iron and free arachidonate, thereby providing a previously unrecognized mechanism for limiting lipid peroxidation, free radical damage, and proinflammatory cascades during times of cellular stress.

  18. Chiral resolution of derivatized amino acids using uniformly sized molecularly imprinted polymers in hydro-organic mobile phases.

    PubMed

    Haginaka, Jun; Kagawa, Chino

    2004-04-01

    Uniformly sized molecularly imprinted polymers (MIPs) for Boc-L-Trp were prepared using ethylene glycol dimethacrylate (EDMA) as the cross-linker, and methacylic acid (MAA) and/or 4-vinylpyridine (4-VPY) as the functional monomers or without use of a functional monomer. The MIPs prepared were evaluated using acetonitrile or a mixture of phosphate buffer and acetonitrile as the mobile phase. The Boc-L-Trp-imprinted EDMA polymers can recognize Boc-L-Trp by its molecular shape, and can thus afford the enantioseparation of Boc-Trp. Besides the molecular shape recognition, the hydrophobic interactions with the polymer backbones as well as the hydrogen-bonding interactions of Boc-L-Trp with carboxyl and pyridyl groups in the polymers should work for the retention and recognition of Boc-L-Trp on the imprinted MAA- co-EDMA and 4-VPY- co-EDMA polymers, respectively, in the hydro-organic mobile phase. The hydrogen-bonding interactions seem to become dominant when only acetonitrile is used as the mobile phase. The Boc-L-Trp-imprinted 4-VPY- co-EDMA polymers gave the highest retentivity and enantioselectivity for Boc-Trp among the MIPs prepared. However, the simultaneous use of MAA and 4-VPY was not effective for the enantioseparation of Boc-Trp in a hydro-organic mobile phase. Furthermore, the baseline separation of Boc-Trp enantiomers was attained within 10 min on the Boc-L-Trp-imprinted 4-VPY- co-EDMA polymers under the optimized HPLC conditions.

  19. Task 1.16 - Enhanced Mobility of Dense Nonaqueous-Phase Liquids (DNAPLs) Using Dissolved Humic Acids

    SciTech Connect

    Edwin S. Olson; Marc D. Kurz

    1998-02-01

    Chlorinated solvent contamination is widespread across the U.S. Department of Energy (DOE) complex and other industrial facilities. Because of the physical properties of dense nonaqueous-phase liquids (DNAPLs), current treatment technologies are generally incapable of completely removing contamination from the source area. Incomplete removal means that the residual DNAPL WN persist as a long-term source of groundwater contamination. When DNALPs occur in the subsurface, they resist remediation, owing to low water volubility, high viscosity and interracial tension, and microbial recalcitrance. Because of their high density and polarity, they are usually found sorbed to aquifer solids or in pools on impermeable materials. Surfactants have been used with some success to reduce interracial tension between the aqueous and organic phases and improve volubility of DNAPLs. However, surfactants are expensive and toxic and exhibit an oxygen demand. An alternative is the use of dissolved humic acids in improving DNAPL mobilization and solubilization. Humic acids, a natural form of organic carbon, are abundant, inexpensive, and nontoxic; biodegrade slowly (low oxygen demand); and have excellent mobilization properties. The present work is to establish the feasibility of using hurnates for enhancing DNAPL remediation.

  20. Prediction of the chromatographic retention of acid-base compounds in pH buffered methanol-water mobile phases in gradient mode by a simplified model.

    PubMed

    Andrés, Axel; Rosés, Martí; Bosch, Elisabeth

    2015-03-13

    Retention of ionizable analytes under gradient elution depends on the pH of the mobile phase, the pKa of the analyte and their evolution along the programmed gradient. In previous work, a model depending on two fitting parameters was recommended because of its very favorable relationship between accuracy and required experimental work. It was developed using acetonitrile as the organic modifier and involves pKa modeling by means of equations that take into account the acidic functional group of the compound (carboxylic acid, protonated amine, etc.). In this work, the two-parameter predicting model is tested and validated using methanol as the organic modifier of the mobile phase and several compounds of higher pharmaceutical relevance and structural complexity as testing analytes. The results have been quite good overall, showing that the predicting model is applicable to a wide variety of acid-base compounds using mobile phases prepared with acetonitrile or methanol.

  1. Transport of fluorescent bile acids by the isolated perfused rat liver: kinetics, sequestration, and mobilization.

    PubMed

    Holzinger, F; Schteingart, C D; Ton-Nu, H T; Cerrè, C; Steinbach, J H; Yeh, H Z; Hofmann, A F

    1998-08-01

    Hepatocyte transport of six fluorescent bile acids containing nitrobenzoxadiazolyl (NBD) or a fluorescein derivative on the side chain was compared with that of natural bile acids using the single-pass perfused rat liver. Compounds were infused at 40 nmol/g liver min for 15 minutes; hepatic uptake and biliary recovery were measured; fractional extraction, intrinsic basolateral clearance, and sequestration (nonrecovery after 45 minutes of additional perfusion) were calculated. Fluorescent bile acids were efficiently extracted during the first 3 minutes (70%-97%), but net extraction decreased with time mostly because of regurgitation into the perfusate. For cholylglycine and ursodeoxycholylglycine (UDC-glycine), extraction was 94% to 99%, and regurgitation did not occur. Intrinsic hepatic clearance of fluorescent bile acids (2-7 mL/g liver x min) was lower than that of cholylglycine (9.0 +/- 0.6; mean +/- SD) and UDC-glycine (21.4 +/- 0.4). Sequestration at 60 minutes was 8% to 26% for fluorescent bile acids with a cholyl moiety (cholylglycylaminofluorescein [CGamF], cholyllysylfluorescein [C-L-F], cholyl-[N epsilon-NBD]-lysine [C-L-NBD], and cholylaminofluorescein [CamF]), 32% for ursodeoxycholylaminofluorescein (UDCamF), and 88% for ursodeoxycholyl-(N epsilon-NBD)lysine (UDC-L-NBD). Cholylglycine and UDC-glycine had <3% retention. Biliary secretion of sequestered UDCamF, but not of UDC-L-NBD, was induced by adding dibutyryl cyclic adenosine monophosphate (DBcAMP) to the perfusate, possibly by translocation to the canaliculus of pericanalicular vesicles containing fluorescent bile acids. Biliary secretion of UDC-L-NBD, but not of UDCamF, was induced by adding cholyltaurine or UDC-taurine, possibly by inhibition of binding to intracellular constituents or of transport into organelles. It is concluded that fluorescent bile acids are efficiently transported across the basolateral membrane, but in contrast to natural conjugated bile acids, are sequestered in the

  2. High-Resolution Electrospray Ionization/Ion Mobility Spectrometer for Detection of Abiotic Amino Acids

    NASA Technical Reports Server (NTRS)

    Beegle, L. W.; Terrell, C. A.; Kim, H.; Kanik, I.

    2003-01-01

    One of the primary goals of the current NASA thrust in Astrobiology is the detection and identification of organic molecules as part of an in-situ lander platform on the surface of Mars or Europa. The identification of these molecules should help determine whether indigenous organisms exist on the surface of Mars or in an undersea environment on Europa. In addition, a detailed organic chemical inventory of surface and near surface molecules will help elucidate the possibilities of life elsewhere in the Universe. Terrestrial life has, as its backbone, the family of molecules known as the amino acids (AA), and while AA can be found in the terrestrial environments as part of more complex molecules, such as peptides, and proteins, they also exist as individual molecules due to of the hydrolyses of biopolymers. In terrestrial biochemistry, there are 20 principal amino acids which are necessary for life. However, some forms of these molecules can be found in nature synthesized via abiotic process. For example, they are known to exist extraterrestrially as a component of carbonaceous meteorites. The idea that amino acids are readily created by abiotic means has been demonstrated by their positive identification in the Murchison CM2 meteorite, which fell in 1969. This meteorite was analyzed before contamination by terrestrial microbes could result. Three laboratories individually tested parts of the meteorite and concluded that the amino acids present in them were indigenous to the meteorite because, among other reasons, they had equal L- and D- enantiomers. Final identification of the constituents of the Murchison included 33 amino acids which have no known biotic source, 11 amino acids which have limited distribution and 8 (Glycine, Alanine, Valine, Proline, Leucine, Isoleucine, Aspartic Acid, and Glutamic Acid), which readily occur in terrestrial proteins.

  3. Systemic resistance in citrus to Tetranychus urticae induced by conspecifics is transmitted by grafting and mediated by mobile amino acids.

    PubMed

    Agut, Blas; Gamir, Jordi; Jaques, Josep A; Flors, Victor

    2016-10-01

    Recent research suggests that systemic signalling and communication between roots and leaves plays an important role in plant defence against herbivores. In the present study, we show that the oviposition of the two-spotted spider mite Tetranychus urticae in the systemic leaves of citrus rootstock Citrus aurantium (sour orange) was reduced by 50% when a lower leaf was previously infested with conspecifics. Metabolomic and gene expression analysis of the root efflux revealed a strong accumulation of glutamic acid (Glu) that triggered the expression of the citrus putative glutamate receptor (GRL) in the shoots. Additionally, uninfested sour orange systemic leaves showed increased expression of glutamate receptors and higher amounts of jasmonic acid (JA) and 12-oxo-phytodienoic acid in plants that were previously infested. Glu perception in the shoots induced the JA pathway, which primed LOX-2 gene expression when citrus plants were exposed to a second infestation. The spider mite-susceptible citrus rootstock Cleopatra mandarin (C. unshiu) also expressed systemic resistance, although the resistance was less effective than the resistance in sour orange. Surprisingly, the mobile signal in Cleopatra mandarin was not Glu, which suggests a strong genotype-dependency for systemic signalling in citrus. When the cultivar Clemenules (C. clementina) was grafted onto sour orange, there was a reduction in symptomatic leaves and T. urticae populations compared to the same cultivar grafted onto Cleopatra mandarin. Thus, systemic resistance is transmitted from the roots to the shoots in citrus and is dependent on rootstock resistance.

  4. Systemic resistance in citrus to Tetranychus urticae induced by conspecifics is transmitted by grafting and mediated by mobile amino acids

    PubMed Central

    Agut, Blas; Gamir, Jordi; Jaques, Josep A.; Flors, Victor

    2016-01-01

    Recent research suggests that systemic signalling and communication between roots and leaves plays an important role in plant defence against herbivores. In the present study, we show that the oviposition of the two-spotted spider mite Tetranychus urticae in the systemic leaves of citrus rootstock Citrus aurantium (sour orange) was reduced by 50% when a lower leaf was previously infested with conspecifics. Metabolomic and gene expression analysis of the root efflux revealed a strong accumulation of glutamic acid (Glu) that triggered the expression of the citrus putative glutamate receptor (GRL) in the shoots. Additionally, uninfested sour orange systemic leaves showed increased expression of glutamate receptors and higher amounts of jasmonic acid (JA) and 12-oxo-phytodienoic acid in plants that were previously infested. Glu perception in the shoots induced the JA pathway, which primed LOX-2 gene expression when citrus plants were exposed to a second infestation. The spider mite-susceptible citrus rootstock Cleopatra mandarin (C. unshiu) also expressed systemic resistance, although the resistance was less effective than the resistance in sour orange. Surprisingly, the mobile signal in Cleopatra mandarin was not Glu, which suggests a strong genotype-dependency for systemic signalling in citrus. When the cultivar Clemenules (C. clementina) was grafted onto sour orange, there was a reduction in symptomatic leaves and T. urticae populations compared to the same cultivar grafted onto Cleopatra mandarin. Thus, systemic resistance is transmitted from the roots to the shoots in citrus and is dependent on rootstock resistance. PMID:27683726

  5. Transfer of arachidonate from phosphatidylcholine to phosphatidylethanolamine and triacylglycerol in guinea pig alveolar macrophages

    SciTech Connect

    Nijssen, J.G.; Oosting, R.S.; Nkamp, F.Pv.; van den Bosch, H.

    1986-10-01

    Guinea pig alveolar macrophages were labeled by incubation with either arachidonate or linoleate. Arachidonate labeled phosphatidylcholine (PC), phosphatidylethanolamine (PE) and triglycerides (TG) equally well, with each lipid containing about 30% of total cellular radioactivity. In comparison to arachidonate, linoleate was recovered significantly less in PE (7%) and more in TG (47%). To investigate whether redistributions of acyl chains among lipid classes took place, the macrophages were incubated with 1-acyl-2-(1-/sup 14/C)arachidonoyl PC or 1-acyl-2-(1-/sup 14/C)linoleoyl PC. After harvesting, the cells incubated with 1-acyl-2-(1-/sup 14/C)linoleoyl PC contained 86% of the recovered cellular radioactivity in PC, with only small amounts of label being transferred to PE and TG (3 and 6%, respectively). More extensive redistributions were observed with arachidonate-labeled PC. In this case, only 60% of cellular radioactivity was still associated with PC, while 22 and 12%, respectively, had been transferred to PE and TG. Arachidonate transfer from PC to PE was unaffected by an excess of free arachidonate which inhibited this transfer to TG for over 90%, indicating that different mechanisms or arachidonoyl CoA pools were involved in the transfer of arachidonate from PC to PE and TG. Cells prelabeled with 1-acyl-2-(1-/sup 14/C)arachidonoyl PC released /sup 14/C-label into the medium upon further incubation. This release was slightly stimulated by zymosan and threefold higher in the presence of the Ca2+-ionophore A23187. Labeling of macrophages with intact phospholipid molecules appears to be a suitable method for studying acyl chain redistribution and release reactions.

  6. The European Food Safety Authority recommendation for polyunsaturated fatty acid composition of infant formula overrules breast milk, puts infants at risk, and should be revised.

    PubMed

    Crawford, Michael A; Wang, Yiqun; Forsyth, Stewart; Brenna, J Thomas

    2015-12-01

    The European Food Safety Authority (EFSA) has concluded from a limited review of the literature that although docosahexaenoic acid (DHA) is required for infant formula, arachidonic acid is not required "even in the presence of DHA" (EFSA Journal, 12 (2014) 3760). This flawed opinion is grounded in human trials which tested functionality of DHA in neural outcomes and included arachidonic acid ostensibly to support growth. The EFSA report mistakes a nutrient ubiquitous in the diets of newborn infants, through breast milk and with wide-ranging health and neurodevelopmental effects, for an optional drug targeted to a particular outcome that is properly excluded when no benefit is found for that particular outcome. Arachidonic acid has very different biological functions compared to DHA, for example, arachidonic acid has unique functions in the vasculature and in specific aspects of immunity. Indeed, the overwhelming majority of trials include both DHA and arachidonic acid, and test development specific to DHA such as neural and visual development. DHA suppresses membrane arachidonic acid concentrations and its function. An infant formula with DHA and no arachidonic acid runs the risk of cardio and cerebrovascular morbidity and even mortality through suppression of the favorable oxylipin derivatives of arachidonic acid. The EFSA recommendation overruling breast milk composition should be revised forthwith, otherwise being unsafe, ungrounded in most of the evidence, and risking lifelong disability.

  7. Target identification of volatile metabolites to allow the differentiation of lactic acid bacteria by gas chromatography-ion mobility spectrometry.

    PubMed

    Gallegos, Janneth; Arce, Cristina; Jordano, Rafael; Arce, Lourdes; Medina, Luis M

    2017-04-01

    The purpose of this work was to study the potential of gas chromatography-ion mobility spectrometry (GC-IMS) to differentiate lactic acid bacteria (LAB) through target identification and fingerprints of volatile metabolites. The LAB selected were used as reference strains for their influence in the flavour of cheese. The four strains of LAB can be distinguished by the fingerprints generated by the volatile organic compounds (VOCs) emitted. 2-butanone, 2-pentanone, 2-heptanone and 3-methyl-1-butanol were identified as relevant VOCs for Lactobacillus casei and Lactobacillus paracasei subsp. paracasei. 2-Butanone and 3-methyl-1-butanol were identified in Lactococcus lactis subsp. lactis and Lactococcus cremoris subsp. cremoris. The IMS signals monitoring during a 24-30h period showed the growth of the LAB in vitro. The results demonstrated that GC-IMS is a useful technology for bacteria recognition and also for screening the aromatic potential of new isolates of LAB.

  8. Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and the release of a-linolenic from membrane lipid. The adjustment of membrane lipid fluidity occurs through changes in unsaturated fatty acid levels, a function provided by the regulated activity of...

  9. Group X Secreted Phospholipase A2 Releases ω3 Polyunsaturated Fatty Acids, Suppresses Colitis, and Promotes Sperm Fertility*

    PubMed Central

    Murase, Remi; Sato, Hiroyasu; Yamamoto, Kei; Ushida, Ayako; Nishito, Yasumasa; Ikeda, Kazutaka; Kobayashi, Tetsuyuki; Yamamoto, Toshinori; Taketomi, Yoshitaka; Murakami, Makoto

    2016-01-01

    Within the secreted phospholipase A2 (sPLA2) family, group X sPLA2 (sPLA2-X) has the highest capacity to hydrolyze cellular membranes and has long been thought to promote inflammation by releasing arachidonic acid, a precursor of pro-inflammatory eicosanoids. Unexpectedly, we found that transgenic mice globally overexpressing human sPLA2-X (PLA2G10-Tg) displayed striking immunosuppressive and lean phenotypes with lymphopenia and increased M2-like macrophages, accompanied by marked elevation of free ω3 polyunsaturated fatty acids (PUFAs) and their metabolites. Studies using Pla2g10-deficient mice revealed that endogenous sPLA2-X, which is highly expressed in the colon epithelium and spermatozoa, mobilized ω3 PUFAs or their metabolites to protect against dextran sulfate-induced colitis and to promote fertilization, respectively. In colitis, sPLA2-X deficiency increased colorectal expression of Th17 cytokines, and ω3 PUFAs attenuated their production by lamina propria cells partly through the fatty acid receptor GPR120. In comparison, cytosolic phospholipase A2 (cPLA2α) protects from colitis by mobilizing ω6 arachidonic acid metabolites, including prostaglandin E2. Thus, our results underscore a previously unrecognized role of sPLA2-X as an ω3 PUFA mobilizer in vivo, segregated mobilization of ω3 and ω6 PUFA metabolites by sPLA2-X and cPLA2α, respectively, in protection against colitis, and the novel role of a particular sPLA2-X-driven PUFA in fertilization. PMID:26828067

  10. Formation of Iron Complexes from Trifluoroacetic Acid Based Liquid Chromatography Mobile Phases as Interference Ions in LC-ESI-MS Analysis

    PubMed Central

    Shukla, Anil; Zhang, Rui; Orton, Daniel; Zhao, Rui; Clauss, Therese; Moore, Ronald; Smith, Richard

    2011-01-01

    Two unexpected singly charged ions at m/z 1103 and 944 have been observed in mass spectra obtained from electrospray ionization-mass spectrometric analysis of liquid chromatography effluents with mobile phases containing trifluoroacetic acid that severely interfered with sample analysis. Accurate mass measurement and tandem mass spectrometry studies revealed that these two ions are composed of three components; clusters of trifluoroacetic acid, clusters of mass 159 and iron. Formation of these ions is inhibited by removing trifluoroacetic acid from the mobile phases and using formic acid in its place, replacing the stainless steel union with a titanium union or by adding a small blank fused silica capillary column between the chromatography column and the electrospray tip via a stainless steel union without any adverse effects to chromatographic separation, peak broadening or peptide identifications. PMID:21504012

  11. A role for AMPK in the inhibition of glucose-6-phosphate dehydrogenase by polyunsaturated fatty acids

    SciTech Connect

    Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M.; Salati, Lisa M.

    2009-10-09

    Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as {beta}-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser{sup 307} phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids.

  12. A ROLE FOR AMPK IN THE INHIBITION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE BY POLYUNSATURATED FATTY ACIDS

    PubMed Central

    Kohan, Alison B.; Talukdar, Indrani; Walsh, Callee M.; Salati, Lisa M.

    2009-01-01

    Both polyunsaturated fatty acids and AMPK promote energy partitioning away from energy consuming processes, such as fatty acid synthesis, towards energy generating processes, such as β-oxidation. In this report, we demonstrate that arachidonic acid activates AMPK in primary rat hepatocytes, and that this effect is p38 MAPK-dependent. Activation of AMPK mimics the inhibition by arachidonic acid of the insulin-mediated induction of G6PD. Similar to intracellular signaling by arachidonic acid, AMPK decreases insulin signal transduction, increasing Ser307 phosphorylation of IRS-1 and a subsequent decrease in AKT phosphorylation. Overexpression of dominant-negative AMPK abolishes the effect of arachidonic acid on G6PD expression. These data suggest a role for AMPK in the inhibition of G6PD by polyunsaturated fatty acids. PMID:19646964

  13. Perfluorinated alkylated acids in groundwater and drinking water: identification, origin and mobility.

    PubMed

    Eschauzier, Christian; Raat, Klaasjan J; Stuyfzand, Pieter J; De Voogt, Pim

    2013-08-01

    Human exposure to perfluorinated alkylated acids (PFAA) occurs primarily via the dietary intake and drinking water can contribute significantly to the overall PFAA intake. Drinking water is produced from surface water and groundwater. Waste water treatment plants have been identified as the main source for PFAA in surface waters and corresponding drinking water. However, even though groundwater is an important source for drinking water production, PFAA sources remain largely uncertain. In this paper, we identified different direct and indirect sources of PFAA to groundwater within the catchment area of a public supply well field (PSWF) in The Netherlands. Direct sources were landfill leachate and water draining from a nearby military base/urban area. Indirect sources were infiltrated rainwater. Maximum concentrations encountered in groundwater within the landfill leachate plume were 1.8 μg/L of non branched perfluorooctanoic acid (L-PFOA) and 1.2 μg/L of perfluorobutanoic acid (PFBA). Sum concentrations amounted to 4.4 μg/L total PFAA. The maximum concentration of ΣPFAA in the groundwater originating from the military camp was around 17 ng/L. Maximum concentrations measured in the groundwater halfway the landfill and the PWSF (15 years travel distance) were 29 and 160 ng/L for L-PFOA and PFBA, respectively. Concentrations in the groundwater pumping wells (travel distance >25 years) were much lower: 0.96 and 3.5 ng/L for L-PFOA and PFBA, respectively. The chemical signature of these pumping wells corresponded to the signature encountered in other wells sampled which were fed by water that had not been in contact with potential contaminant sources, suggesting a widespread diffuse contamination from atmospheric deposition.

  14. Acidification, heavy metal mobility and nutrient accumulation in the soil-plant system of a revegetated acid mine wasteland.

    PubMed

    Yang, Sheng-Xiang; Liao, Bin; Li, Jin-tian; Guo, Tao; Shu, Wen-Sheng

    2010-08-01

    A revegetation program was established at an extreme acidic and metal-toxic pyrite/copper mine wasteland in Guangdong Province, PR China using a combination of four native grass species and one non-native woody species. It was continued and monitored for 2 y. The emphasis was on acidification, metal mobility and nutrient accumulation in the soil-plant system. Our results showed the following: (i) the acid-forming potential of the mine soils decreased steadily with time, which might be due to plant root-induced changes inhibiting the oxidization of sulphide minerals; (ii) heavy metal extractability (diethylene-triamine-pentaacetic acid-extractable Pb and Zn) in the soils increased with time despite an increase in soil pH, which might be attributed to soil disturbance and plant rhizospheric processes, as well as a consequence of the enhanced metal accumulation in plants over time; and (iii) the vegetation cover increased rapidly with time, and plant development accelerated the accumulation of major nutrients (organic matter, total and ammonium-N, and available P and K). The 2-y field experiment demonstrates that direct seeding/planting of native plant species in combination with lime and manure amelioration is a practical approach to the initial establishment of a self-sustaining vegetation cover on this metalliferous and sulphide-bearing mine wasteland. However, heavy metal accumulation in the soil-plant system should be of great concern, and long-term monitoring of ecological risk must be an integral part of such a restoration scheme.

  15. Agonist activation of arachidonate-regulated Ca2+-selective (ARC) channels in murine parotid and pancreatic acinar cells.

    PubMed

    Mignen, Olivier; Thompson, Jill L; Yule, David I; Shuttleworth, Trevor J

    2005-05-01

    ARC channels (arachidonate-regulated Ca(2+)-selective channels) are a novel type of highly Ca(2+)-selective channel that are specifically activated by low concentrations of agonist-induced arachidonic acid. This activation occurs in the absence of any depletion of internal Ca(2+) stores (i.e. they are 'non-capacitative'). Previous studies in HEK293 cells have shown that these channels provide the predominant pathway for the entry of Ca(2+) seen at low agonist concentrations where oscillatory [Ca(2+)](i) signals are typically produced. In contrast, activation of the more widely studied store-operated Ca(2+) channels (e.g. CRAC channels) is only seen at higher agonist concentrations where sustained 'plateau-type'[Ca(2+)](i) responses are observed. We have now demonstrated the presence of ARC channels in both parotid and pancreatic acinar cells and shown that, again, they are specifically activated by the low concentrations of appropriate agonists (carbachol in the parotid, and both carbachol and cholecystokinin in the pancreas) that are associated with oscillatory [Ca(2+)](i) signals in these cells. Uncoupling the receptor-mediated activation of cytosolic phospholipase A(2) (cPLA(2)) with isotetrandrine reduces the activation of the ARC channels by carbachol and, correspondingly, markedly inhibits the [Ca(2+)](i) signals induced by low carbachol concentrations, whilst those signals seen at high agonist concentrations are essentially unaffected. Interestingly, in the pancreatic acinar cells, activation by cholecystokinin induces a current through the ARC channels that is only approximately 60% of that seen with carbachol. This is consistent with previous reports indicating that carbachol-induced [Ca(2+)](i) signals in these cells are much more dependent on Ca(2+) entry than are the cholecystokinin-induced responses.

  16. Mobility of Transgenic Nucleic Acids and Proteins within Grafted Rootstocks for Agricultural Improvement

    PubMed Central

    Haroldsen, Victor M.; Szczerba, Mark W.; Aktas, Hakan; Lopez-Baltazar, Javier; Odias, Mar Joseph; Chi-Ham, Cecilia L.; Labavitch, John M.; Bennett, Alan B.; Powell, Ann L. T.

    2012-01-01

    Grafting has been used in agriculture for over 2000 years. Disease resistance and environmental tolerance are highly beneficial traits that can be provided through use of grafting, although the mechanisms, in particular for resistance, have frequently been unknown. As information emerges that describes plant disease resistance mechanisms, the proteins, and nucleic acids that play a critical role in disease management can be expressed in genetically engineered (GE) plant lines. Utilizing transgrafting, the combination of a GE rootstock with a wild-type (WT) scion, or the reverse, has the potential to provide pest and pathogen resistance, impart biotic and abiotic stress tolerance, or increase plant vigor and productivity. Of central importance to these potential benefits is the question of to what extent nucleic acids and proteins are transmitted across a graft junction and whether the movement of these molecules will affect the efficacy of the transgrafting approach. Using a variety of specific examples, this review will report on the movement of organellar DNA, RNAs, and proteins across graft unions. Attention will be specifically drawn to the use of small RNAs and gene silencing within transgrafted plants, with a particular focus on pathogen resistance. The use of GE rootstocks or scions has the potential to extend the horticultural utility of grafting by combining this ancient technique with the molecular strategies of the modern era. PMID:22645583

  17. Analysis of Phenacylester Derivatives of Fatty Acids from Human Skin Surface Sebum by Reversed-Phase HPLC: Chromatographic Mobility as a Function of Physico-Chemical Properties

    PubMed Central

    Bodoprost, Juliana; Rosemeyer, Helmut

    2007-01-01

    A set of 13 fatty acids was transformed into their phenacyl esters by reaction with phenacyl bromide in acetonitrile using 18-crown-6 as phase-transfer catalyst. Conditions for the RP-18 HPL chromatographic separation of most of the esters has been worked out. Using this standard the fatty acid spectra from skin surface sebum lipids of 17 test persons was taken after microwave-assisted hydrolysis, neutralization and extraction with n-hexane. Quantitative evaluation of the chromatograms exhibits that oleic acid predominates in the sebum of all test persons. In the second part of the work the chromatographic mobility (RE values) of fatty acid phenacyl esters is correlated with calculated physico-chemical parameters of the corresponding acids. The best linear correlation was found between the RE and the logP values. This is helpful for the structural elucidation of un-identified fatty acids in a chromatogram.

  18. EnEnvironmental Mobility of Pu(IV) in the Presence of Ethylenediaminetetraacetic Acid: Myth or Reality

    SciTech Connect

    Rai, Dhanpat; Moore, Dean A.; Rosso, Kevin M.; Felmy, Andrew R.; Bolton, Harvey

    2008-07-01

    Ethylenediaminetetracetic acid (EDTA), which was co-disposed with Pu at several U. S. Department of Energy sites, has been reported to enhance the solubility and transport of Pu. It is generally assumed that this enhanced transport of Pu in geologic environments is a result of complexation of Pu(IV) with EDTA. However, the fundamental bases for this assumption have never been fully explored. Whether EDTA can mobilize Pu(IV) in geologic environments is dependent on many factors, chief among them are not only the complexation constants of Pu with EDTA and dominant oxidation state and the nature of Pu solids, but also 1) the complexation constants of environmentally important metal ions (e.g. Fe, Al, Ca, Mg) that compete with Pu for EDTA and 2) EDTA interactions with geomedia (e.g., adsorption, biodegradation) that reduce effective EDTA concentrations available for complexation. Extensive studies over a large range of pH values (1 to 14) and EDTA concentrations (0.0001 to 0.01 M) as a function of time were conducted on the solubility of 2-line ferrihydrite (Fe(OH)3(s)), PuO2(am) in the presence of different concentrations of Ca ions, and mixtures of PuO2(am) and Fe(OH)3(s). The solubility data were interpreted using Pitzer’s ion-interaction approach to determine/validate the solubility product of Fe(OH)3(s), the complexation constants of Pu(IV)-EDTA and Fe(III)-EDTA, and to determine the affect of EDTA in solubilizing Pu(IV) from PuO2(am) in the presence of Fe(III) compounds and aqueous Ca concentrations. Predictions based on these extensive fundamental data show that environmental mobility of Pu as a result of Pu(IV)-EDTA complexation as reported/implied in the literature is a myth rather than the reality.

  19. ω-Alkynyl lipid surrogates for polyunsaturated fatty acids: free radical and enzymatic oxidations.

    PubMed

    Beavers, William N; Serwa, Remigiusz; Shimozu, Yuki; Tallman, Keri A; Vaught, Melissa; Dalvie, Esha D; Marnett, Lawrence J; Porter, Ned A

    2014-08-13

    Lipid and lipid metabolite profiling are important parameters in understanding the pathogenesis of many diseases. Alkynylated polyunsaturated fatty acids are potentially useful probes for tracking the fate of fatty acid metabolites. The nonenzymatic and enzymatic oxidations of ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were compared to that of linoleic and arachidonic acid. There was no detectable difference in the primary products of nonenzymatic oxidation, which comprised cis,trans-hydroxy fatty acids. Similar hydroxy fatty acid products were formed when ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid were reacted with lipoxygenase enzymes that introduce oxygen at different positions in the carbon chains. The rates of oxidation of ω-alkynylated fatty acids were reduced compared to those of the natural fatty acids. Cyclooxygenase-1 and -2 did not oxidize alkynyl linoleic but efficiently oxidized alkynyl arachidonic acid. The products were identified as alkynyl 11-hydroxy-eicosatetraenoic acid, alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid, and alkynyl prostaglandins. This deviation from the metabolic profile of arachidonic acid may limit the utility of alkynyl arachidonic acid in the tracking of cyclooxygenase-based lipid oxidation. The formation of alkynyl 11-hydroxy-8,9-epoxy-eicosatrienoic acid compared to alkynyl prostaglandins suggests that the ω-alkyne group causes a conformational change in the fatty acid bound to the enzyme, which reduces the efficiency of cyclization of dioxalanyl intermediates to endoperoxide intermediates. Overall, ω-alkynyl linoleic acid and ω-alkynyl arachidonic acid appear to be metabolically competent surrogates for tracking the fate of polyunsaturated fatty acids when looking at models involving autoxidation and oxidation by lipoxygenases.

  20. Probing the segmental mobility and energy of the active zones of a protein chain (aspartic acid protease) by a coarse-grained bond-fluctuation Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Pandey, Ras; Farmer, Barry

    2008-03-01

    A protein chain such as aspartic acid protease is described by a specific sequence of 99 residues each with its own specific characteristics. In a coarse-grained description, the backbone of a protein chain is described by nodes tethered together by peptide bonds where each node (the amino acid group) is characterized by molecular weight and hydrophobicity. A well-developed and somewhat mature computational modeling tool for the polymer chain such as the bond-fluctuation model is used to study such a specific protein chain with its constitutive amino groups and their sequence. The relative magnitude of hydrophobicity is used to develop appropriate interaction potentials for these amino acid groups in explicit solvent. The Metropolis algorithm is used to move each node and solvent constituent. Local energy and mobility of each amino group are analyzed along with global energy, mobility, and conformation of the protein chain. Effect of the solvent interaction and its concentration on these quantities will be presented.

  1. Calculation of the hole mobilities of the three homopolynucleotides, poly(guanilic acid), poly(adenilic acid), and polythymidine in the presence of water and Na+ ions.

    PubMed

    Bende, Attila; Bogár, Ferenc; Beleznay, Ferenc; Ladik, János

    2008-12-01

    Recent high resolution x-ray diffraction experiments have determined the structure of nucleosomes. In it 147 base pair long DNA B superhelix is wrapped around the eight nucleohistone proteins. They have found that there are many hydrogen-bonds (H-bonds) between the negative sites phosphate (PO4-) groups DNA, and first of all there is the positively charged lysine and arginine side chains of the histones. This means that there is a non-negligible charge transfer from DNA to the proteins causing a hole current in DNA and an electronic one in the proteins. If the relative positions of the two macromolecules change due to some external disturbances, the DNA moves away from the protein and can be read. If this happens simultaneously at several nucleosomes and at many places in chromatin (built up from the nucleosomes), undesired genetic information becomes readable. This final end can cause the occurrence of oncoproteins at an undesired time point which most probably disturbs the self-regulation of a differentiated cell. The connection of these chain of events with the initiation of cancer is obvious. To look into the details of these events we have used the detailed band structures of the four homopolynucleotides in the presence of water and natrium (Na+) ions calculated previously with the help of the ab initio Hartree-Fock crystal orbital method. We have found that in the case of three homopolynucleotides the width of their valence band is broad enough (approximately 10 times broader than the thermal energy at 300K) for the application of the simple deformation potential approximation for transport calculations. With the help of this we have determined the hole mobilities at 300K and 180K of poly(guanilic acid), poly(adenilic acid), and polythimidine (polycytidine has a too narrow valence band for the application of the deformation potential method). The obtained mobilities are large enough to allow Bloch-type conduction in these systems. At the end of the paper we

  2. Calculation of the hole mobilities of the three homopolynucleotides, poly(guanilic acid), poly(adenilic acid), and polythymidine in the presence of water and Na+ ions

    NASA Astrophysics Data System (ADS)

    Bende, Attila; Bogár, Ferenc; Beleznay, Ferenc; Ladik, János

    2008-12-01

    Recent high resolution x-ray diffraction experiments have determined the structure of nucleosomes. In it 147 base pair long DNA B superhelix is wrapped around the eight nucleohistone proteins. They have found that there are many hydrogen-bonds (H-bonds) between the negative sites phosphate ( PO4- ) groups DNA, and first of all there is the positively charged lysine and arginine side chains of the histones. This means that there is a non-negligible charge transfer from DNA to the proteins causing a hole current in DNA and an electronic one in the proteins. If the relative positions of the two macromolecules change due to some external disturbances, the DNA moves away from the protein and can be read. If this happens simultaneously at several nucleosomes and at many places in chromatin (built up from the nucleosomes), undesired genetic information becomes readable. This final end can cause the occurrence of oncoproteins at an undesired time point which most probably disturbs the self-regulation of a differentiated cell. The connection of these chain of events with the initiation of cancer is obvious. To look into the details of these events we have used the detailed band structures of the four homopolynucleotides in the presence of water and natrium ( Na+ ) ions calculated previously with the help of the ab initio Hartree-Fock crystal orbital method. We have found that in the case of three homopolynucleotides the width of their valence band is broad enough ( ˜10 times broader than the thermal energy at 300K ) for the application of the simple deformation potential approximation for transport calculations. With the help of this we have determined the hole mobilities at 300K and 180K of poly(guanilic acid), poly(adenilic acid), and polythimidine (polycytidine has a too narrow valence band for the application of the deformation potential method). The obtained mobilities are large enough to allow Bloch-type conduction in these systems. At the end of the paper we discuss

  3. Characterization and Acid-Mobilization Study of Iron-Containing Mineral Dust Source Materials

    SciTech Connect

    Cwiertny, David M.; Baltrusaitis, Jonas; Hunter, Gordon J.; Laskin, Alexander; Scherer, Michelle; Grassian, Vicki H.

    2008-03-04

    Processes that solubilize the iron in mineral dust aerosols may increase the amount of iron supplied to ocean surface waters, and thereby stimulate phytoplankton productivity. It was recently proposed that mixing of mineral dusts with SO2 and HNO3 produces extremely acidic environments that favor the formation of bioavailable Fe(II). Here, four authentic mineral dust source materials (Saudi Beach sand (SB), Inland Saudi sand (IS), Saharan Sand (SS) and China Loess (CL)) and one commercial reference material (Arizona Test Dust (AZTD)) were spectroscopically characterized, and their dissolution at pH 1 was examined in aqueous batch systems. Spectroscopic analyses indicated that the bulk and near-surface region of all samples possessed similar elemental compositions and that iron was unevenly distributed among dust 10 particles. Mössbauer spectroscopy revealed Fe(III) in all samples, although SB, CL and AZTD also contained appreciable Fe(II). Both Fe(II) and Fe(III) were primarily substituted into aluminosilicates, although CL, AZTD and IS also contained Fe(III) oxides. Total iron solubility (defined as the summed concentration of dissolved Fe(II) and Fe(III) measured after 24 h) ranged 14 between 4-12% of the source materials’ iron content, but did not scale with either the surface area or the iron content of the samples. This suggests that other factors such as iron speciation and mineralogy may play a key role in iron solubility. Also, the elevated nitrate concentrations encountered from nitric acid at pH 1 suppressed dissolution of Fe(II) from AZTD, CL and SB particles, which we propose results from the surface-mediated, non-photochemical reduction of nitrate by Fe(II).

  4. Trace metal mobilization from oil sands froth treatment thickened tailings exhibiting acid rock drainage.

    PubMed

    Kuznetsova, Alsu; Kuznetsov, Petr; Foght, Julia M; Siddique, Tariq

    2016-11-15

    Froth treatment thickened tailings (TT) are a waste product of bitumen extraction from surface-mined oil sands ores. When incubated in a laboratory under simulated moist oxic environmental conditions for ~450d, two different types of TT (TT1 and TT2) exhibited the potential to generate acid rock drainage (ARD) by producing acid leachate after 250 and 50d, respectively. We report here the release of toxic metals from TT via ARD, which could pose an environmental threat if oil sands TT deposits are not properly managed. Trace metal concentrations in leachate samples collected periodically revealed that Mn and Sr were released immediately even before the onset of ARD. Spikes in Co and Ni concentrations were observed both pre-ARD and during active ARD, particularly in TT1. For most elements measured (Fe, Cr, V, As, Cu, Pb, Zn, Cd, and Se), leaching was associated with ARD production. Though equivalent acidification (pH2) was achieved in leachate from both TT types, greater metal release was observed from TT2 where concentrations reached 10,000ppb for Ni, 5000ppb for Co, 3000ppb for As, 2000ppb for V, and 1000ppb for Cr. Generally, metal concentrations decreased in leachate with time during ARD and became negligible by the end of incubation (~450d) despite appreciable metals remaining in the leached TT. These results suggest that using TT for land reclamation purposes or surface deposition for volume reduction may unfavorably impact the environment, and warrants application of appropriate strategies for management of pyrite-enriched oil sands tailings streams.

  5. Mobility of Po and U-isotopes under acid mine drainage conditions: an experimental approach with samples from Río Tinto area (SW Spain).

    PubMed

    Barbero, L; Gázquez, M J; Bolívar, J P; Casas-Ruiz, M; Hierro, A; Baskaran, M; Ketterer, M E

    2014-12-01

    Under acid mine drainage (AMD) conditions, the solubilities and mobilities of many elements are vastly different from conditions prevailing in most natural waters. Studies are underway in the Río Tinto area (Iberian Pyrite Belt), in order to understand the behavior and mobility of long-lived U-series radionuclides under AMD conditions. A set of leaching experiments utilizing typical country rocks from the Tinto River basin, waste rock pile composite materials, iron-rich riverbed sediments and gossan (weathered naturally rock) were performed towards this purpose. Initial leaching experiments using distilled water kept in contact with solid material for 300, 100, 50 and 1 h resulted in very low concentrations of U with (234)U/(238)U activity ratios close to equilibrium and activity concentrations of (210)Po < 0.03 mBq/g. Leaching experiments performed with sulfuric acid media (0.1 and 0.01 M), and contact times between the solid and solution for 24 h were conducted to quantify the amount of U-isotopes and (210)Po leached, and the radioactive disequilibria generated between the radionuclides in the leachate. These experiments show that Po mobility in acidic conditions (pH around 1-2) is very low, with (210)Po activity in the leachate to be 6% in average for the solid sample. By contrast, mobility of U-isotopes is higher than that of Po, around 1.2%.

  6. Enantioseparation of mandelic acid derivatives by high performance liquid chromatography with substituted β-cyclodextrin as chiral mobile phase additive and evaluation of inclusion complex formation

    PubMed Central

    Tong, Shengqiang; Zhang, Hu; Shen, Mangmang

    2014-01-01

    The enantioseparation of ten mandelic acid derivatives was performed by reverse phase high performance liquid chromatography with hydroxypropyl-β-cyclodextrin (HP-β-CD) or sulfobutyl ether-β-cyclodextrin (SBE-β-CD) as chiral mobile phase additives, in which inclusion complex formations between cyclodextrins and enantiomers were evaluated. The effects of various factors such as the composition of mobile phase, concentration of cyclodextrins and column temperature on retention and enantioselectivity were studied. The peak resolutions and retention time of the enantiomers were strongly affected by the pH, the organic modifier and the type of β-cyclodextrin in the mobile phase, while the concentration of buffer solution and temperature had a relatively low effect on resolutions. Enantioseparations were successfully achieved on a Shimpack CLC-ODS column (150×4.6 mm i.d., 5 μm). The mobile phase was a mixture of acetonitrile and 0.10 mol L-1 of phosphate buffer at pH 2.68 containing 20 mmol L-1 of HP-β-CD or SBE-β-CD. Semi-preparative enantioseparation of about 10 mg of α-cyclohexylmandelic acid and α-cyclopentylmandelic acid were established individually. Cyclodextrin-enantiomer complex stoichiometries as well as binding constants were investigated. Results showed that stoichiomertries for all the inclusion complex of cyclodextrin-enantiomers were 1:1. PMID:24893270

  7. Membrane-based continuous remover of trifluoroacetic acid in mobile phase for LC-ESI-MS analysis of small molecules and proteins.

    PubMed

    Zhou, Zhigui; Zhang, Jialing; Xing, Jiawei; Bai, Yu; Liao, Yiping; Liu, Huwei

    2012-07-01

    We developed a "continuous" trifluoroacetic acid (TFA) remover based on electrodialysis with bipolar membrane for online coupling of liquid chromatography (LC) and electrospray ionization mass spectrometry (ESI-MS) using TFA containing mobile phase. With the TFA remover as an interface, the TFA anion in the mobile phase was removed based on electrodialysis mechanism, and meanwhile, the anion exchange membrane was self-regenerated by the hydroxide ions produced by the bipolar membrane. So the remover could continuously work without any additional regeneration process. The established LC-TFA remover-MS system has been successfully applied for the qualitative and quantitative analysis of small molecules as well as proteins.

  8. Digestion of feed amino acids in the rumen and intestine of steers measured using a mobile nylon bag technique.

    PubMed

    Taghizadeh, A; Danesh Mesgaran, M; Valizadeh, R; Shahroodi, F Eftekhar; Stanford, K

    2005-05-01

    The disappearance of dry matter (DM), crude protein (CP), and amino acids (AA) in steers after rumen incubation and intestinal passage of alfalfa hay, barley hay, corn silage, barley grain, corn grain, wheat bran, meat meal, fish meal, cottonseed meal, and soybean meal were measured in 3 steers using a mobile nylon bag technique. Ruminal degradation of individual AA differed between feedstuffs. For barley hay and corn silage, the ruminal disappearance of total AA was higher and lower than the other feedstuffs, respectively. The intestinal digestibility of total AA in alfalfa hay was lower than the digestion of CP. The intestinal digestibility of Arg and His was higher than that of total AA in alfalfa hay, meat meal, cottonseed meal, soybean meal, barley hay, and wheat bran. In addition, the intestinal digestibility of Lys was higher than that of total AA in alfalfa hay, meat meal, cottonseed meal, soybean meal, barley hay, corn silage, and wheat bran. The intestinal disappearance of CP in most cases was higher than that of DM. The results indicated that feedstuffs with lower ruminal disappearance of DM, CP, total AA, essential AA, and nonessential AA generally had a higher intestinal disappearance, resulting in a relatively constant total tract disappearance. These results could be used to improve the current system of diet formulation in ruminants.

  9. Group X Secreted Phospholipase A2 Releases ω3 Polyunsaturated Fatty Acids, Suppresses Colitis, and Promotes Sperm Fertility.

    PubMed

    Murase, Remi; Sato, Hiroyasu; Yamamoto, Kei; Ushida, Ayako; Nishito, Yasumasa; Ikeda, Kazutaka; Kobayashi, Tetsuyuki; Yamamoto, Toshinori; Taketomi, Yoshitaka; Murakami, Makoto

    2016-03-25

    Within the secreted phospholipase A2(sPLA2) family, group X sPLA2(sPLA2-X) has the highest capacity to hydrolyze cellular membranes and has long been thought to promote inflammation by releasing arachidonic acid, a precursor of pro-inflammatory eicosanoids. Unexpectedly, we found that transgenic mice globally overexpressing human sPLA2-X (PLA2G10-Tg) displayed striking immunosuppressive and lean phenotypes with lymphopenia and increased M2-like macrophages, accompanied by marked elevation of free ω3 polyunsaturated fatty acids (PUFAs) and their metabolites. Studies usingPla2g10-deficient mice revealed that endogenous sPLA2-X, which is highly expressed in the colon epithelium and spermatozoa, mobilized ω3 PUFAs or their metabolites to protect against dextran sulfate-induced colitis and to promote fertilization, respectively. In colitis, sPLA2-X deficiency increased colorectal expression of Th17 cytokines, and ω3 PUFAs attenuated their production by lamina propria cells partly through the fatty acid receptor GPR120. In comparison, cytosolic phospholipase A2(cPLA2α) protects from colitis by mobilizing ω6 arachidonic acid metabolites, including prostaglandin E2 Thus, our results underscore a previously unrecognized role of sPLA2-X as an ω3 PUFA mobilizerin vivo, segregated mobilization of ω3 and ω6 PUFA metabolites by sPLA2-X and cPLA2α, respectively, in protection against colitis, and the novel role of a particular sPLA2-X-driven PUFA in fertilization.

  10. IL-1. alpha. increases arachidonyl-CoA: Lysophospholipid acyltransterase activity and stimulates ( sup 3 H) arachidonate incorporation into phospholipids in rat mesangial cells

    SciTech Connect

    Nakazato, Y.; Sedor, J.R. )

    1992-01-01

    The proinflammatory cytokine interleukin-1{alpha} is a potent stimulus of prostaglandin synthesis. The authors have previously shown that IL-1 amplifies mesangial cell prostaglandin synthesis by inducing synthesis of a non-pancreatic phospholipase A{sub 2}. Phospholipase A{sub 2}. Phospholipase A{sub 2} activation results in the formation of lysophospholipids and free fatty acids. They now investigate the effects of IL-1{alpha} on reacylation of lysophospholipids. Incubations with IL-1{alpha} for 24 hours significantly stimulated mesangial cell ({sup 3}H)arachidonic acid incorporation but not ({sup 3}H)oleic acid incorporation into phosphatidylinositol and phosphatidylethanolamine. Lysophospholipid acyltransferase activity was measured in vitro. Cytokine treatment increased enzyme activity when lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylinositol were used as exogenous substrates. They conclude that IL-1 promotes cellular phospholipid remodeling by stimulating the deacylation and reacylation of phospholipids.

  11. Formation of iron complexs from trifluoroacetic acid based liquid chromatography mobile phases as interference ions in liquid chromatography/electrospray ionization mass spectrometric analysis

    SciTech Connect

    Shukla, Anil K.; Zhang, Rui; Orton, Daniel J.; Zhao, Rui; Clauss, Therese RW; Moore, Ronald J.; Smith, Richard D.

    2011-05-30

    Two unexpected singly charged ions at m/z 1103 and 944 have been observed in mass spectra obtained from electrospray ionization-mass spectrometric analysis of liquid chromatography effluents with mobile phases containing trifluoroacetic acid. Accurate mass measurement and tandem mass spectrometry studies revealed that these two ions are not due to any contamination from solvents and chemicals used for mobile and stationary phases or from the laboratory atmospheric environment. Instead these ions are clusters of trifluoroacetic acid formed in association with acetonitrile, water and iron from the stainless steel union used to connect the column with the electrospray tip and to apply high voltage; the molecular formulae are Fe+((OH)(H2O)2)9(CF3COOH)5 and Fe+((OH)(H2O)2)6 (CF3COOH)5.

  12. Effects of ionic liquid as additive and the pH of the mobile phase on the retention factors of amino benzoic acids in RP-HPLC.

    PubMed

    Zheng, J; Polyakova, Y; Row, K H

    2007-01-01

    As an organic salt, ionic liquids are widely used as new solvent media. In this paper, three positional isomers, such as o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acid are separated with four different ionic liquids as additives to the mobile phase using reversed-phase (RP) high-performance liquid chromatography (HPLC). Amino benzoic acids are biologically active substances; the p-isomer is present in a group of water-soluble vitamins and is widely known as a sunscreen agent. The ionic liquids used are 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methylsulfate, and 1-octyl-3-methylimidazolium methylsulfate. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of the ionic liquid, and the effect of the pH of the mobile phase on the retention factor of the amino benzoic acid isomers are studied. Separation with the ionic liquid in the eluent was better than the separation without the ionic liquid. The pH mainly affected the retention and elution order of the solutes in RP-HPLC.

  13. Omega-3 and -6 fatty acids allocate somatic and germline lipids to ensure fitness during nutrient and oxidative stress in Caenorhabditis elegans

    PubMed Central

    Lynn, Dana A.; Dalton, Hans M.; Sowa, Jessica N.; Wang, Meng C.; Soukas, Alexander A.; Curran, Sean P.

    2015-01-01

    Animals in nature are continually challenged by periods of feast and famine as resources inevitably fluctuate, and must allocate somatic reserves for reproduction to abate evolutionary pressures. We identify an age-dependent lipid homeostasis pathway in Caenorhabditis elegans that regulates the mobilization of lipids from the soma to the germline, which supports fecundity but at the cost of survival in nutrient-poor and oxidative stress environments. This trade-off is responsive to the levels of dietary carbohydrates and organismal oleic acid and is coupled to activation of the cytoprotective transcription factor SKN-1 in both laboratory-derived and natural isolates of C. elegans. The homeostatic balance of lipid stores between the somatic and germ cells is mediated by arachidonic acid (omega-6) and eicosapentaenoic acid (omega-3) precursors of eicosanoid signaling molecules. Our results describe a mechanism for resource reallocation within intact animals that influences reproductive fitness at the cost of somatic resilience. PMID:26621724

  14. Omega-3 and -6 fatty acids allocate somatic and germline lipids to ensure fitness during nutrient and oxidative stress in Caenorhabditis elegans.

    PubMed

    Lynn, Dana A; Dalton, Hans M; Sowa, Jessica N; Wang, Meng C; Soukas, Alexander A; Curran, Sean P

    2015-12-15

    Animals in nature are continually challenged by periods of feast and famine as resources inevitably fluctuate, and must allocate somatic reserves for reproduction to abate evolutionary pressures. We identify an age-dependent lipid homeostasis pathway in Caenorhabditis elegans that regulates the mobilization of lipids from the soma to the germline, which supports fecundity but at the cost of survival in nutrient-poor and oxidative stress environments. This trade-off is responsive to the levels of dietary carbohydrates and organismal oleic acid and is coupled to activation of the cytoprotective transcription factor SKN-1 in both laboratory-derived and natural isolates of C. elegans. The homeostatic balance of lipid stores between the somatic and germ cells is mediated by arachidonic acid (omega-6) and eicosapentaenoic acid (omega-3) precursors of eicosanoid signaling molecules. Our results describe a mechanism for resource reallocation within intact animals that influences reproductive fitness at the cost of somatic resilience.

  15. Store-operated Ca2+ Entry-associated Regulatory factor (SARAF) Plays an Important Role in the Regulation of Arachidonate-regulated Ca2+ (ARC) Channels.

    PubMed

    Albarran, Letizia; Lopez, Jose J; Woodard, Geoffrey E; Salido, Gines M; Rosado, Juan A

    2016-03-25

    The store-operated Ca(2+)entry-associated regulatory factor (SARAF) has recently been identified as a STIM1 regulatory protein that facilitates slow Ca(2+)-dependent inactivation of store-operated Ca(2+)entry (SOCE). Both the store-operated channels and the store-independent arachidonate-regulated Ca(2+)(ARC) channels are regulated by STIM1. In the present study, we show that, in addition to its location in the endoplasmic reticulum, SARAF is constitutively expressed in the plasma membrane, where it can interact with plasma membrane (PM)-resident ARC forming subunits in the neuroblastoma cell line SH-SY5Y. Using siRNA-based and overexpression approaches we report that SARAF negatively regulates store-independent Ca(2+)entry via the ARC channels. Arachidonic acid (AA) increases the association of PM-resident SARAF with Orai1. Finally, our results indicate that SARAF modulates the ability of AA to promote cell survival in neuroblastoma cells. In addition to revealing new insight into the biology of ARC channels in neuroblastoma cells, these findings provide evidence for an unprecedented location of SARAF in the plasma membrane.

  16. Impaired cytoplasmic ionized calcium mobilization in inherited platelet secretion defects

    SciTech Connect

    Rao, A.K.; Kowalska, M.A.; Disa, J. )

    1989-08-01

    Defects in platelet cytoplasmic Ca++ mobilization have been postulated but not well demonstrated in patients with inherited platelet secretion defects. We describe studies in a 42-year-old white woman, referred for evaluation of easy bruising, and her 23-year-old son. In both subjects, aggregation and {sup 14}C-serotonin secretion responses in platelet-rich plasma (PRP) to adenosine diphosphate (ADP), epinephrine, platelet activating factor (PAF), arachidonic acid (AA), U46619, and ionophore A23187 were markedly impaired. Platelet ADP and adenosine triphosphate (ATP), contents and thromboxane synthesis induced by thrombin and AA were normal. In quin2-loaded platelets, the basal intracellular Ca++ concentration, (Ca++)i, was normal; however, peak (Ca++)i measured in the presence of 1 mmol/L external Ca++ was consistently diminished following activation with ADP (25 mumol/L), PAF (20 mumol/L), collagen (5 micrograms/mL), U46619 (1 mumol/L), and thrombin (0.05 to 0.5 U/mL). In aequorin-loaded platelets, the peak (Ca++)i studied following thrombin (0.05 and 0.5 U/mL) stimulation was diminished. Myosin light chain phosphorylation following thrombin (0.05 to 0.5 U/mL) stimulation was comparable with that in the normal controls, while with ADP (25 mumol/L) it was more strikingly impaired in the propositus. We provide direct evidence that at least in some patients with inherited platelet secretion defects, agonist-induced Ca++ mobilization is impaired. This may be related to defects in phospholipase C activation. These patients provide a unique opportunity to obtain new insights into Ca++ mobilization in platelets.

  17. Despite transient ketosis, the classic high-fat ketogenic diet induces marked changes in fatty acid metabolism in rats.

    PubMed

    Taha, Ameer Y; Ryan, Mary Ann A; Cunnane, Stephen C

    2005-09-01

    In contrast to humans, rats on a high-fat ketogenic diet seem incapable of maintaining plasma beta-hydroxybutyrate above 1 mmol/L for more than a week. Our goal was to determine whether fatty acid metabolism in rats changes despite the absence of sustained ketosis induced by the ketogenic diet. Fatty acid metabolism was assessed as changes in tissue fatty acid profiles and change in 13C-alpha-linolenic acid incorporation into plasma, liver, adipose tissue, and brain lipids. Despite loss of ketosis, the ketogenic diet reduced some polyunsaturated fatty acids in adipose tissue (up to 44%) and plasma (up to 90%) but raised polyunsaturates in liver triglycerides by up to 25-fold and raised arachidonic and docosahexaenoic acids in the brain by 15%. Lower tissue incorporation of 13C-alpha-linolenic acid but higher unlabeled and 13C-labeled docosahexaenoic acid in brain supports the view that the principal changes in fatty acid composition resulted from enhanced mobilization of polyunsaturates from adipose tissue to liver and brain. In the absence of sustained ketosis, changes in fatty acid metabolism resulting in an increase in brain polyunsaturates, particularly docosahexaenoic acid may, nevertheless, contribute to the seizure protection by the ketogenic diet.

  18. The effect of isosaccharinic acid (ISA) on the mobilization of metals in municipal solid waste incineration (MSWI) dry scrubber residue.

    PubMed

    Svensson, Malin; Berg, Magnus; Ifwer, Karin; Sjöblom, Rolf; Ecke, Holger

    2007-06-01

    Co-landfilling of incineration ash and cellulose might facilitate the alkaline degradation of cellulose. A major degradation product is isosaccharinic acid (ISA), a complexing agent for metals. The impact of ISA on the mobility of Pb, Zn, Cr, Cu and Cd from a municipal solid waste incineration dry scrubber residue was studied at laboratory using a reduced 2(5-1) factorial design. Factors investigated were the amount of calcium isosaccharinate (Ca(ISA)(2)), L/S ratio, temperature, contact time and type of atmosphere (N(2), air, O(2)). The effects of pH and Ca(ISA)(2) as well as other factors on the leaching of metals were quantified and modelled using multiple linear regression (alpha=0.05). Cd was excluded from the study since the concentrations were below the detection limit. The presence of Ca(ISA)(2) resulted in a higher leaching of Cu indicating complex formation. Ca(ISA)(2) alone had no effect on the leaching of Pb, Zn and Cr. A secondary effect on the mobilization was predicted to occur since Ca(ISA)(2) had a positive effect on the pH and the leaching of Pb, Zn and Cr increased with increasing pH. The leaching of Pb varied from 24 up to 66 wt.% of the total Pb amount (1.74+/-0.02 g(kgTS)(-1)) in the dry scrubber residue. The corresponding interval for Zn (7.29+/-0.07 g(kgTS)(-1)) and Cu (0.50+/-0.02 g(kgTS)(-1)) were 0.5-14 wt.% of Zn and 0.8-70wt.% of Cu. Maximum leaching of Cr (0.23+/-0.03 g(kgTS)(-1)) was 4.0 wt.%. At conditions similar to a compacted and covered landfill (4 degrees C, 7 days, 0 vol.% O(2)) the presence of ISA can increase the leaching of Cu from 2 to 46 wt.% if the amount of cellulose-based waste increases 20 times, from the ratio 1:100 to 1:5. As well, the leaching of Pb, Zn, and Cr can increase from 32 to 54 wt.% (Pb), 0.8-8.0 wt.% (Zn), and 0.5 to 4.0 wt.% (Cr) depending on the amount of cellulose and L/S ratio and pH value. Therefore, a risk (alpha=0.05) exists that higher amounts of metals are leached from landfills where cellulose

  19. Community mobilization and social marketing to promote weekly iron-folic acid supplementation: a new approach toward controlling anemia among women of reproductive age in Vietnam.

    PubMed

    Khan, Nguyen Cong; Thanh, Hoang Thi Kim; Berger, Jacques; Hoa, Pham Thuy; Quang, Nguyen Dinh; Smitasiri, Suttilak; Cavalli-Sforza, Tommaso

    2005-12-01

    Community-based social marketing and mobilization increased knowledge and participation in preventive weekly iron-folic acid supplementation among women of reproductive age in Vietnam. Rates of buying and taking the weekly supplement containing 60 mg elemental iron and 3.5 mg folic acid among non-pregnant women of reproductive age was between 55% and 92%. Free distribution to pregnant women of the weekly supplement containing 120 mg iron and 3.5 mg folic acid covered almost all pregnant women during the project. In developing countries where community women's groups and health networks are strong, preventive supplementation can be successfully promoted to encourage active participation in the prevention and control of iron-deficiency anemia.

  20. Gas chromatography with tandem differential mobility spectrometry of fatty acid alkyl esters and the selective detection of methyl linolenate in biodiesels by dual-stage ion filtering.

    PubMed

    Pasupuleti, D; Pierce, K; Eiceman, G A

    2015-11-20

    Alkyl esters of fatty acids (FAAEs) with carbon numbers from 8 to 20 formed protonated monomers and proton bound dimers through atmospheric pressure chemical ionization reactions and these gas ions were characterized for their field dependent mobility coefficients using differential mobility spectrometry (DMS). Separation of ion peaks with a vapor modifier was achieved for ions with masses of 317-1033 Da though the differences in these coefficients and the resolution of ion peaks decreased proportionally with increased ion mass. Differences in dispersion curves were sufficient to isolate ions from specific FAAEs in the effluent of a gas chromatograph by dual stage ion filtering using a tandem DMS detector. Methyl linolenate was isolated from nearby eluting methyl oleate, methyl stearate and methyl linoleate within analysis times of 10s without measureable complications from charge suppression in the ion source or leakage in filtering of ions with close proximity of dispersion behavior.

  1. Comprehensive investigation of the influence of acidic, basic, and organic mobile phase compositions on bioanalytical assay sensitivity in positive ESI mode LC/MS/MS.

    PubMed

    Rainville, Paul D; Smith, Norman W; Cowan, David; Plumb, Robert S

    2012-02-05

    The sensitivity and accuracy of a bioanalytical method is critical in defining the pharmacokinetic (PK) parameters of a potential new chemical entity (NCE). Inhaled therapeutics and low dose NCEs present one of the most significant analytical challenges to the bioanalyst, due to their low systemic concentration. The sensitivity of a bioanalytical LC/MS/MS based assay can be influenced by multiple parameters, including: mobile phase composition, extraction efficiency and chromatographic performance. In this work, we discuss the influence of acidic (pH 3), and basic (pH 10) aqueous mobile phases in conjunction with the two most common organic modifiers used in HPLC, acetonitrile and methanol, on the assay sensitivity of twenty-four probe pharmaceuticals in solvent and biological fluid extract. The study showed that when the test probe pharmaceuticals were analyzed with basic aqueous mobile phases compared to standard acidic conditions the following results were observed: increases in chromatographic peak area ranging from 1.2 to 9.6 fold for twenty-one of the test compounds as well as increased signal-to-noise for greater than seventy percent of the compounds. This observed increase in the MS response was not necessarily related to the later elution of the analyte in a higher organic composition under basic conditions. This was demonstrated as seven out of the twenty-four (approximately thirty percent) of the probe pharmaceuticals tested, eluted earlier, or with the same retention time, under basic conditions, and still produced a greater signal-to-noise when analyzed under these basic conditions. Also observed were decreases in chromatographic peak width, and increases in the retention time of very hydrophilic pharmaceutical compounds. The effect of the mobile phase combinations on the retention and MS response of the choline-containing phospholipids present in precipitated plasma was also investigated, as these analytes are a major source of interference when

  2. Effects of three low-molecular-weight organic acids (LMWOAs) and pH on the mobilization of arsenic and heavy metals (Cu, Pb, and Zn) from mine tailings.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2013-02-01

    Natural organic acids may play an important role in influencing the mobility of toxic contaminants in the environment. The mobilization of arsenic (As) and heavy metals from an oxidized Pb-Zn mine tailings sample in the presence of three low-molecular-weight organic acids, aspartic acid, cysteine, and succinic acid, was investigated at a mass ratio of 10 mg organic additive/g mine tailings in this study. The effect of pH was also evaluated. The mine tailings sample, containing elevated levels of As (2,180 mg/kg), copper (Cu, 1,100 mg/kg), lead (Pb, 12,860 mg/kg), and zinc (Zn, 5,075 mg/kg), was collected from Bathurst, New Brunswick, Canada. It was found that the organic additives inhibited As and heavy metal mobilization under acidic conditions (at pH 3 or 5), but enhanced it under neutral to alkaline conditions (at pH above 7) through forming aqueous organic complexes. At pH 11, As, Cu, Pb, and Zn were mobilized mostly by the organic additives, 45, 46, 1,660, and 128 mg/kg by aspartic acid, 31, 28, 1,040, and 112 mg/kg by succinic acid, and 53, 38, 2,020, and 150 mg/kg by cysteine, respectively, whereas those by distilled water were 6, 16, 260, and 52 mg/kg, respectively. It was also found that the mobilization of As and the heavy metals was closely correlated, and both were closely correlated to Fe mobilization. Arsenic mobilization by the three LMWOAs was found to be consistent with the order of the stability of Fe-, Cu-, Pb-, and Zn-organic ligand complexes. The organic acids might be used potentially in the natural attenuation and remediation of As and heavy metal-contaminated sites.

  3. [Chiral separation of five beta-blockers using di-n-hexyl L-tartrate-boric acid complex as mobile phase additive by reversed-phase liquid chromatography].

    PubMed

    Yang, Juan; Wang, Lijuan; Guo, Qiaoling; Yang, Gengliang

    2012-03-01

    A reversed-phase high performance liquid chromatographic (HPLC) method using the di-n-hexyl L-tartrate-boric acid complex as a chiral mobile phase additive was developed for the enantioseparation of five beta-blockers including propranolol, esmolol, metoprolol, bisoprolol and sotalol. In order to obtain a better enantioseparation, the influences of concentrations of di-n-butyl L-tartrate and boric acid, the type, concentration and pH of the buffer, methanol content as well as the molecular structure of analytes were extensively investigated. The separation of the analytes was performed on a Venusil MP-C18 column (250 mm x 4.6 mm, 5 microm). The mobile phase was 15 mmol/L ammonium acetate-methanol containing 60 mmol/L boric acid, 70 mmol/L di-n-hexyl L-tartrate (pH 6.00). The volume ratios of 15 mmol/L ammonium acetate to methanol were 20: 80 for propranolol, esmolol, metoprolol, bisoprolol and 30: 70 for sotalol. The flow rate was 0.5 mL/min and the detection wavelength was set at 214 nm. Under the optimized conditions, baseline enantioseparation was obtained separately for the five pairs of analytes.

  4. Consumption of aquaculture waste affects the fatty acid metabolism of a benthic invertebrate.

    PubMed

    White, Camille A; Bannister, Raymond J; Dworjanyn, Symon A; Husa, Vivian; Nichols, Peter D; Kutti, Tina; Dempster, Tim

    2017-02-17

    Trophic subsidies can drive widespread ecological change, thus knowledge of how keystone species respond to subsidies is important. Aquaculture of large carnivorous fish generates substantial waste as faeces and lost feed, providing a food source to mobile benthic invertebrates. We used a controlled feeding study combined with a field survey to better understand the interaction between salmon aquaculture and the sea urchin, Echinus acutus, a dominant mobile invertebrate in Norwegian fjords. We tested if diets affected urchin fatty acid composition by feeding them one of three diet treatments ("aquafeed", "composite" and "natural") for 10weeks. To test if proximity to fish farms altered E. acutus fatty acid composition, populations were sampled at 10 locations in Hardangerfjord and Masfjord (Western Norway) from directly adjacent and up to 12km from farms. Fatty acids were measured in gonads and eggs in the diet experiment and in gonads and gut contents from wild animals. Urchins directly assimilated aquaculture waste at farm sites, as evidenced by elevated linoleic acid (LA), oleic acid (OA) and ∑LA, OA in their tissues. The diet experiment highlighted the biosynthetic and selective dietary sparing capacity of E. acutus in both gonads and eggs, with evidence for the elongation and desaturation of eicosapentaenoic acid (EPA) and arachidonic acid (ARA) from C18 fatty acid precursors. Elevated biosynthesis of non-methylene interrupted (NMI) fatty acids, in particular 20:3Δ7,11,14 and 20:2 Δ5,11, were also linked to a high C18 fatty acid, low ≥C20 long-chain polyunsaturated fatty acid (LC-PUFA) diet. Fatty acid composition of gonads of wild urchins indicated a highly variable diet. The study indicates that the generalist feeding ecology of E. acutus, coupled with extensive biosynthetic capacity, enables it to exploit aquaculture waste as an energy-rich trophic subsidy.

  5. The Association of Fatty Acids With Breast Cancer.

    DTIC Science & Technology

    1995-08-09

    Experimental studies have shown that omega-6 fatty acids enhance and omega - 3 fatty acids suppress oncogenesis. Correlational studies also indicate...that breast cancer incidence is positively linked to omega-6 consumption but is negatively related to intake of omega - 3 fatty acids, derived mainly from...arachidonic acid), and omega - 3 fatty acids (20:5n3, eicosapentaenoic acid; 22:6n-3, docosahexaenoic acid) were similar in cases and controls

  6. Changes in mobility of toxic elements during the production of phosphoric acid in the fertilizer industry of Huelva (SW Spain) and environmental impact of phosphogypsum wastes.

    PubMed

    Pérez-López, Rafael; Alvarez-Valero, Antonio M; Nieto, José Miguel

    2007-09-30

    Presently, about 3 million tonnes of phosphogypsum are being generated annually in Spain as by-product from phosphoric acid in a fertilizer factory located in Huelva (southwestern Iberian Peninsula). Phosphate rock from Morocco is used as raw material in this process. Phosphogypsum wastes are stored in a stack containing 100Mt (approximately 1200ha of surface) over salt marshes of an estuary formed by the confluence of the Tinto and Odiel rivers, less than 1km away from the city centre. A very low proportion of this waste is used to improve fertility of agricultural soils in the area of the Guadalquivir river valley (Seville, SW Spain). The chemical speciation of potentially toxic elements (Ba, Cd, Cu, Ni, Sr, U and Zn) in phosphogypsum and phosphate rock was performed using the modified BCR-sequential extraction procedure, as described by the European Community Bureau of Reference (1999). This study has been done with the main of: (1) evaluate changes in the mobility of metals during the production of phosphoric acid; (2) estimate the amount of mobile metals that can affect the environmental surrounding; and (3) verify the environmentally safe use of phosphogypsum as an amendment to agricultural soils. The main environmental concern associated to phosphoric acid production is that Uranium, a radiotoxic element, is transferred from the non-mobile fraction in the phosphate rock to the bioavailable fraction in phosphogypsum in a rate of 23%. Around 21% of Ba, 6% of Cu and Sr, 5% of Cd and Ni, and 2% of Zn are also contained in the water-soluble phase of the final waste. Considering the total mass of phosphogypsum, the amount of metals easily soluble in water is approximately 6178, 3089, 1931, 579, 232, 193 and 77t for Sr, U, Ba, Zn, Ni, Cu and Cd, respectively. This gives an idea of the pollution potential of this waste.

  7. Specific high-affinity binding of fatty acids to epidermal cytosolic proteins

    SciTech Connect

    Raza, H.; Chung, W.L.; Mukhtar, H. )

    1991-08-01

    Cytosol from rat, mouse, and human skin or rat epidermis was incubated with (3H)arachidonic acid, (14C)retinoic acid, (14C)oleic acid, (3H)leukotriene A4, (3H)prostaglandin E2 (PGE2) or (3H) 15-hydroxyeicosatetraenoic acid (15-HETE), and protein-bound ligands were separated using Lipidex-1000 at 4C to assess the binding specificity. The binding of oleic acid and arachidonic acid with rat epidermal cytosol was rapid, saturable, and reversible. Binding of oleic acid was competed out with the simultaneous addition of other ligands and found to be in the following order: arachidonic acid greater than oleic acid greater than linoleic acid greater than lauric acid greater than leukotriene A4 greater than 15-HETE = PGE1 greater than PGE2 = PGF2. Scatchard analysis of the binding with arachidonic acid, oleic acid, and retinoic acid revealed high-affinity binding sites with the dissociation constant in the nM range. SDS-PAGE analysis of the oleic acid-bound epidermal cytosolic protein(s) revealed maximum binding at the 14.5 kDa region. The presence of the fatty acid-binding protein in epidermal cytosol and its binding to fatty acids and retinoic acid may be of significance both in the trafficking and the metabolism of fatty acids and retinoids across the skin.

  8. Retention of ionisable compounds on high-performance liquid chromatography XVIII: pH variation in mobile phases containing formic acid, piperazine, tris, boric acid or carbonate as buffering systems and acetonitrile as organic modifier.

    PubMed

    Subirats, Xavier; Bosch, Elisabeth; Rosés, Martí

    2009-03-20

    In the present work dissociation constants of commonly used buffering species, formic acid, piperazine, tris(hydroxymethyl)-aminomethane, boric acid and carbonate, have been determined for several acetonitrile-water mixtures. From these pK(a) values a previous model has been successfully evaluated to estimate pH values in acetonitrile-aqueous buffer mobile phases from the aqueous pH and concentration of the above mentioned buffers up to 60% of acetonitrile, and aqueous buffer concentrations between 0.005 (0.001 mol L(-1) for formic acid-formate) and 0.1 mol L(-1). The relationships derived for the presently studied buffers, together with those established for previously considered buffering systems, allow a general prediction of the pH variation of the most commonly used HPLC buffers when the composition of the acetonitrile-water mobile phase changes during the chromatographic process, such as in gradient elution. Thus, they are an interesting tool that can be easily implemented in general retention models to predict retention of acid-base analytes and optimize chromatographic separations.

  9. Weekly iron-folic acid supplements to prevent anemia among Cambodian women in three settings: process and outcomes of social marketing and community mobilization.

    PubMed

    Kanal, Koum; Busch-Hallen, Jennifer; Cavalli-Sforza, Tommaso; Crape, Byron; Smitasiri, Suttilak

    2005-12-01

    Social marketing and community mobilization approaches were applied in a pilot program to introduce weekly iron-folic acid supplementation to prevent anemia in Cambodian women of reproductive age. The program was implemented in three very different environments: secondary school girls, women working in garment factories in the vicinity of Phnom Penh, and women in rural villages. Each population provided its own challenges and obstacles. However, all three groups of women showed substantial improvements in knowledge about the causes, consequences, and prevention of anemia, and the large majority reported interest in continuing to take the supplements.

  10. Anti-CD3 and concanavalin A-induced human T cell proliferation is associated with an increased rate of arachidonate-phospholipid remodeling. Lack of involvement of group IV and group VI phospholipase A2 in remodeling and increased susceptibility of proliferating T cells to CoA-independent transacyclase inhibitor-induced apoptosis.

    PubMed

    Boilard, E; Surette, M E

    2001-05-18

    In this study arachidonate-phospholipid remodeling was investigated in resting and proliferating human T lymphocytes. Lymphocytes induced to proliferate with either the mitogen concanavalin A or with anti-CD3 (OKT3) in combination with interleukin 2 (OKT3/IL-2) showed a greatly accelerated rate of [3H]arachidonate-phospholipid remodeling compared with resting lymphocytes or with lymphocytes stimulated with OKT3 or IL-2 alone. The concanavalin A-stimulated cells showed a 2-fold increase in the specific activity of CoA-independent transacylase compared with unstimulated cells, indicating that this enzyme is inducible. Stimulation with OKT3 resulted in greatly increased quantities of the group VI calcium-independent phospholipase A2 but not of the quantity of group IV cytosolic phospholipase A2. However, group IV phospholipase A2 became phosphorylated in OKT3-stimulated cells, as determined by decreased electrophoretic mobility. Incubation of cells with the group VI phospholipase A2 inhibitor, bromoenol lactone, or the dual group IV/group VI phospholipase A2 inhibitor, methyl arachidonyl fluorophosphonate, did not block arachidonate-phospholipid remodeling resting or proliferating T cells, suggesting that these phospholipases A2 were not involved in arachidonate-phospholipid remodeling. The incubation of nonproliferating human lymphocytes with inhibitors of CoA-independent transacylase had little impact on cell survival. In contrast, OKT3/IL-2-stimulated T lymphocytes were very sensitive to apoptosis induced by CoA-independent transacylase inhibitors. Altogether these results indicate that increased arachidonate-phospholipid remodeling is associated with T cell proliferation and that CoA-independent transacylase may be a novel therapeutic target for proliferative disorders.

  11. Effects of some iridoids from plant origin on arachidonic acid metabolism in cellular systems.

    PubMed

    Bermejo Benito, P; Díaz Lanza, A M; Silván Sen, A M; De Santos Galindez, J; Fernandez Matellano, L; Sanz Gómez, A; Abad Martínez, M J

    2000-05-01

    Seven iridoid glycosides isolated from different extracts of Scrophularia scorodonia L., namely bartsioside, aucubin, harpagide, harpagoside, 8-acetylharpagide, scorodioside and scropolioside B, had been evaluated for their in vitro anti-inflammatory activity in cellular systems generating COX and LOX metabolites. Structure-activity relationships obtained from in vitro screening results were discussed. Most compounds assayed did not exhibit any significant effect on PGE2- and LTC4-release from calcium ionophore-stimulated mouse peritoneal macrophages. In the LTC4-assay, only aucubin showed a significant effect, with an IC50 value of 72 microM. Harpagoside and harpagide also inhibited release of LTC4, but neither effect reached statistical significance. The release of PGE2 by mouse peritoneal macrophages stimulated with calcium ionophore was inhibited by harpagoside and 8-acetylharpagide, but this effect is not statistically significant. However, most iridoids assayed showed a significant effect on TXB2-release from calcium ionophorestimulated human platelets, with inhibition percentages slightly lower than the reference drug ibuprofen. Only harpagide, scorodioside and scropolioside B had no significant effect on TXB2-release. Our results indicate that selective inhibition of the TX-synthase enzyme may be the primary target of action of most of these iridoids, and one of the mechanisms through which they exert their anti-inflammatory effects.

  12. Effects of Toxins on Arachidonic Acid Metabolism in Cultured Rat Pulmonary Alveolar Macrophages

    DTIC Science & Technology

    1988-12-28

    contributing to their in-vivo, anti-inflammatory effect (19, 20). Pretreatment of macrophages with steriod significantly augmented-the T-2 induced release...effects of steriods are not limited to induction of phospholipase A2 inhibitory protein. Dunham et al. (24) reported that leukotriene B4 (LTB4) and

  13. Arachidonic acid metabolism and inhibition of cyclooxygenase in platelets from asthmatic subjects with aspirin intolerance.

    PubMed

    Bonne, C; Moneret-Vautrin, D A; Wayoff, M; Descharmes, A; Gazel, P; Legrand, A; Kalt, C

    1985-02-01

    Exaggerated inhibition of cyclooxygenase has been proposed as a mechanism of drug-induced bronchospasm in aspirin-intolerant patients. This study, using platelets, shows that inhibition of prostaglandin biosynthesis by aspirin is unmodified in patients when compared with healthy subjects. The ratio of cyclooxygenase:lipoxygenase products is similar in platelets from patients and control subjects. We conclude that the cyclooxygenase alteration observed in cells from the respiratory tract is not generalised to other cells such as platelets. We also propose that the major abnormality in NSAID-intolerant patients would affect receptivity to lipoxygenase products more than their biosynthesis.

  14. STIMULATION OF [3H] ARACHIDONIC ACID RELEASE IN RAT CEREBELLAR GRANULE NEURONS BY POLYBROMINATED DIPHENYL.

    EPA Science Inventory

    Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in electronic equipment, plastics, textiles, and building materials. While the presence of other persistent organic pollutants, such as polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxin...

  15. Sequence-specific nucleic acid mobility using a reversible block copolymer gel matrix and DNA amphiphiles (lipid-DNA) in capillary and microfluidic electrophoretic separations.

    PubMed

    Wagler, Patrick; Minero, Gabriel Antonio S; Tangen, Uwe; de Vries, Jan Willem; Prusty, Deepak; Kwak, Minseok; Herrmann, Andreas; McCaskill, John S

    2015-10-01

    Reversible noncovalent but sequence-dependent attachment of DNA to gels is shown to allow programmable mobility processing of DNA populations. The covalent attachment of DNA oligomers to polyacrylamide gels using acrydite-modified oligonucleotides has enabled sequence-specific mobility assays for DNA in gel electrophoresis: sequences binding to the immobilized DNA are delayed in their migration. Such a system has been used for example to construct complex DNA filters facilitating DNA computations. However, these gels are formed irreversibly and the choice of immobilized sequences is made once off during fabrication. In this work, we demonstrate the reversible self-assembly of gels combined with amphiphilic DNA molecules, which exhibit hydrophobic hydrocarbon chains attached to the nucleobase. This amphiphilic DNA, which we term lipid-DNA, is synthesized in advance and is blended into a block copolymer gel to induce sequence-dependent DNA retention during electrophoresis. Furthermore, we demonstrate and characterize the programmable mobility shift of matching DNA in such reversible gels both in thin films and microchannels using microelectrode arrays. Such sequence selective separation may be employed to select nucleic acid sequences of similar length from a mixture via local electronics, a basic functionality that can be employed in novel electronic chemical cell designs and other DNA information-processing systems.

  16. Fatty acid profiles and relative mobilization during fasting in adipose tissue depots of the American marten (Martes americana).

    PubMed

    Nieminen, Petteri; Rouvinen-Watt, Kirsti; Collinsb, Danielle; Grant, Judy; Mustonen, Anne-Mari

    2006-03-01

    The American marten (Martes americana) is a boreal forest marten with low body adiposity but high metabolic rate. The study describes the FA composition in white adipose tissue depots of the species and the influence of food deprivation on them. American marten (n = 8) were fasted for 2 d with 7 control animals. Fasting resulted in a 13.4% weight loss, while the relative fat mass was >25% lower in the fasted animals. The FA composition of the fat depots of the trunk was quite similar to other previously studied mustelids with 14:0, 16:0, 18:0, 16:1 n-7, 18:1 n-9, and 18:2n-6 as the most abundant FA. In the extremities, there were higher proportions of monounsaturated FA (MUFA) and PUFA. Food deprivation decreased the proportions of 16:0 and 16:1 n-7, while the proportion of long-chain MUFA increased in the trunk. The mobilization of FA was selective, as 16:1 n-7, 18:1 n-9, and particular n-3 PUFA were preferentially mobilized. Relative mobilization correlated negatively with the carbon chain length in saturated FA (SFA) and n-9 MUFA. The delta9-desaturation of SFA enhanced the mobilization of the corresponding MUFA, but the positional isomerism of the first double bond did not correlate consistently with relative mobilization in MUFA or PUFA. In the marten, the FA composition of the extremities was highly resistant to fasting, and the tail tip and the paws contained more long-chain PUFA to prevent the solidification of lipids and to maintain cell membrane fluidity during cooling.

  17. Characterization of the properties of stationary phases for liquid chromatography in aqueous mobile phases using aromatic sulphonic acids as the test compounds.

    PubMed

    Jandera, P; Bocian, S; Molíková, M; Buszewski, B

    2009-01-09

    We investigated the effects of the concentration of naphthalene sulphonic acids (NSAs) as anionic test compounds in the injected sample and of the salt additives to the mobile phase on ion-exclusion. The retention behaviour of NSAs sensitively reflects even minor changes in the ionic and hydrophobic interactions and can be useful for predicting the effects of the stationary phases in reversed-phase chromatography of polar and ionic compounds, both small ones and biopolymers, e.g., oligonucleotides. We studied chromatographic properties of several stationary phases intended for separations in aqueous mobile phases: a C18 column end-capped with polar hydrophilic groups, a densely bonded C8 column doubly end-capped with short alkyl groups, a short alkyl stationary phase designed to keep full pore accessibility in highly-aqueous mobile phases and a Bidentate column with "bridged" C18 groups attached to the silica hydride support. The chemistry and pore structure of various types of column packing materials and of the salt additives to the mobile phase affect the proportion of the pore volume non-accessible to anions due to ion-exclusion and consequently the peak asymmetry and hydrophobic selectivity in reversed-phase chromatography of organic acids. We also addressed the problems connected with the determination of column hold-up volume in aqueous mobile phases. The accessibility of the stationary phase for anionic compounds in contact with the sample zone is affected by ion-exclusion due to repulsive interactions with the negatively charged surface in the pores of the stationary phase. The accessible part of the stationary phase increases and consequently the migration velocity along the column decreases with increasing concentration of the sample in the zone moving along the column. Because of a limited access to the stationary phase, its capacity can be easily overloaded. The combination of the column overload and ion-exclusion effects may result in fronting or

  18. Effect of citric acid on metals mobility in pruning wastes and biosolids compost and metals uptake in Atriplex halimus and Rosmarinus officinalis.

    PubMed

    Tapia, Y; Eymar, E; Gárate, A; Masaguer, A

    2013-05-01

    To assess metal mobility in pruning waste and biosolids compost (pH 6.9 and total concentration of metals in milligram per kilogram of Cd 1.9, Cu 132, Fe 8,513, Mn 192, Pb 81, and Zn 313), shrubs species Atriplex halimus and Rosmarinus officinalis were transplanted in this substrate and irrigated with citric acid (4 g L(-1), pH 2.9) and nutrient solution daily for 60 days. Citric acid significantly increased the concentrations of soluble Mn and Fe in the nutrient substrate solution measured by suction probes, while other metals did not vary in concentration (Cu and Zn) or were not observed at detectable levels (Cd and Pb). In plants, citric acid significantly increased the concentrations of Cu (2.7 ± 0.1-3.3 ± 0.1 mg kg(-1)), Fe (49.2 ± 5.2-76.8 ± 6.8 mg kg(-1)), and Mn (7.2 ± 1.1-11.4 ± 0.7 mg kg(-1)) in leaves of R. officinalis, whereas the concentration of only Mn (25.4 ± 0.3-42.2 ± 2.9 mg kg(-1)) was increased in A. halimus. Increasing Fe and Mn solubility by citric acid addition indicates the possibility of using it to improve plant nutrition. The mobility of metals in this substrate was influenced for the concentration of the metal, the degree of humification of organic matter and its high Fe content.

  19. Selective incorporation of ( sup 15 S)-hydroxyeicosatetraenoic acid in phosphatidylinositol of human neutrophils: Agonist-induced deacylation and transformation of stored hydroxyeicosanoids

    SciTech Connect

    Brezinski, M.E.; Serhan, C.N. )

    1990-08-01

    The uptake and mobilization of (15S)-hydroxy-5,8,11-cis-13-trans-eicosatetraenoic acid (15-HETE), a major product of arachidonic acid metabolism, was examined with human neutrophils. Upon exposure to labeled 15-HETE, PMNs rapidly (15 sec to 20 min) incorporated approximately 20% of the label into phosphatidylinositol, while less than 4% was associated with other phospholipid classes and neutral lipids. This pattern was distinct from that of either labeled arachidonate or labeled(5S)-hydroxy-8,11,14-cis-6-trans-eicosatetraenoic acid (5-HETE), which within 20 min were predominantly associated with triglycerides and phosphatidylcholine. After reversed-phase HPLC, greater than 98% of the label in phosphatidylinositol, isolated from PMNs, was released with phospholipase A2. Upon exposure to either chemotactic peptide (FMLP), phorbol 12-myristate 13-acetate, or an ionophore (A23187), 15-HETE-labeled PMNs released 15-HETE from phosphatidylinositol and displayed an impaired ability to generate leukotriene B4 (LTB4), 20-OH-LTB4, and 20-COOH-LTB4. Deacylated (3H)15-HETE was converted to (5S,15S)-dihydroxy-6,13-trans-8,11-cis-eicosatetraenoic acid (5,15-DHETE), lipoxin A4, and lipoxin B4, each carrying 3H label. PMNs labeled with 5-HETE also released and transformed this HETE when stimulated. However, the profile of labeled products differed between PMNs with either esterified 15-HETE or 5-HETE. When activated, 5-HETE-labeled PMNs generated both 5,20-DHETE and 5,15-DHETE but not labeled lipoxins. Threshold aggregation induced by FMLP with 15-HETE-labeled PMNs was inhibited, while the threshold response was relatively unimpaired with either A23187 or phorbol 12-myristate 13-acetate-induced aggregation. Results indicate that 15-HETE is esterified into phosphatidylinositol of PMNs, which can be mobilized and transformed upon exposure of the cells to a second signal.

  20. Aqueous sulfuric acid as the mobile phase in cation ion chromatography for determination of histamine, putrescine, and cadaverine in fish samples.

    PubMed

    Liao, Benjamin S; Sram, Jackie; Cain, Teresa T; Halcrow, Kenneth R

    2011-01-01

    Aqueous sulfuric acid can be used as the mobile phase in cation ion chromatography to separate the three biogenic amines, putrescine, cadaverine, and histamine, from fish. Various concentrations of aqueous sulfuric acid were investigated to optimize the separation of these three biogenic amines. Aqueous sulfuric acid (5.0 mM) was found to be optimum for the separation and was used to determine the three biogenic amines in fish. The LOQ, defined as the lowest level of the standard calibration curve, was 0.055 ppm (equivalent to 0.55 microg/g sample) for putrescine, 0.05 ppm (equivalent to 0.5 microg/g sample) for cadaverine, and 1.0 ppm (equivalent to 10 microg/g sample) for histamine. From statistical analysis of the LOQ, the method detection limit was 0.003 ppm for putrescine, 0.009 ppm for cadaverine, and 0.16 ppm for histamine. For sample preparation, the fish was composited, homogenized in methanol-water (75 + 25, v/v), incubated for 15 min at 60 degrees C, and centrifuged. The sample solution was micron-filtered before injection. The mobile phase flow rate was 0.8 mL/min under isocratic conditions at room temperature (15-25 degrees C). The three biogenic amines were separated in the order of increasing retention time, i.e., putrescine, cadaverine, and histamine, within 30 min. The chromatograms showed complete peak separation of the three amines regardless of the difference in fish matrixes.

  1. Influence of phenolic constituents from Yucca schidigera bark on arachidonate metabolism in vitro.

    PubMed

    Wenzig, Eva M; Oleszek, Wieslaw; Stochmal, Anna; Kunert, Olaf; Bauer, Rudolf

    2008-10-08

    Yucca schidigera Roezl. (Agavaceae) has been traditionally used to treat a variety of diseases including arthritis and rheumatism. Phenolic constituents isolated from yucca bark, such as resveratrol, trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, and the yuccaols, have been shown to possess various activities in vitro, such as antioxidant, radical scavenging, iNOS expression inhibitory, and platelet aggregation inhibitory effects. In the present study, the influence of a phenolic-rich fraction from yucca bark and of its main phenolic constituents on key enzymes of arachidonate metabolism was investigated. The fraction and the pure phenolics were shown to inhibit COX-1, COX-2, and LTB 4 formation by 5-LOX in vitro to different extents. The degree of COX-1 inhibition was found to be strongly dependent on the substitution pattern of ring B of the stilbenic moiety. The same trend was observed for the COX-2 inhibitory potential, which was, however, in general much lower for the yuccaols as compared with resveratrol. Resveratrol was also the only compound possessing an LTB 4 formation inhibitory activity. The inhibitory activity on key enzymes of arachidonate metabolism observed in this study might contribute to the explanation of the anti-inflammatory and antiplatelet effects observed for Y. schidigera and its phenolic constituents.

  2. Incorporating Novel Mobile Health Technologies Into Management of Knee Osteoarthritis in Patients Treated With Intra-Articular Hyaluronic Acid: Rationale and Protocol of a Randomized Controlled Trial

    PubMed Central

    Skrepnik, Nebojsa; Toselli, Richard M; Leroy, Bruno

    2016-01-01

    Background Osteoarthritis (OA) of the knee is one of the leading causes of disability in the United States. One relatively new strategy that could be helpful in the management of OA is the use of mHealth technologies, as they can be used to increase physical activity and promote exercise, which are key components of knee OA management. Objective Currently, no published data on the use of a mHealth approach to comprehensively monitor physical activity in patients with OA are available, and similarly, no data on whether mHealth technologies can impact outcomes are available. Our objective is to evaluate the effectiveness of mHealth technology as part of a tailored, comprehensive management strategy for patients with knee OA. Methods The study will assess the impact of a smartphone app that integrates data from a wearable activity monitor (thereby both encouraging changes in mobility as well as tracking them) combined with education about the benefits of walking on patient mobility. The results from the intervention group will be compared with data from a control group of individuals who are given the same Arthritis Foundation literature regarding the benefits of walking and wearable activity monitors but who do not have access to the data from those monitors. Activity monitors will capture step count estimates and will compare those with patients’ step goals, calories burned, and distance walked. Patients using the novel smartphone app will be able to enter information on their daily pain, mood, and sleep quality. The relationships among activity and pain, activity and mood, and sleep will be assessed, as will patient satisfaction with and adherence to the mobile app. Results We present information on an upcoming trial that will prospectively assess the ability of a mobile app to improve mobility for knee OA patients who are treated with intra-articular hyaluronic acid. Conclusions We anticipate the results of this study will support the concept that m

  3. The Role of a Double Molecular Anchor on the Mobility and Self-Assembly of Thiols on Au(111): The Case of Mercaptobenzoic Acid.

    PubMed

    Rodríguez González, Miriam C; Carro, Pilar; Pensa, Evangelina; Vericat, Carolina; Salvarezza, Roberto; Hernández Creus, Alberto

    2017-01-09

    The dynamics of the self-assembly process of thiol molecules on Au(111) is affected by the interplay between molecule-substrate and molecule-molecule interactions. Therefore, it is interesting to explore the effect of a second anchor to the gold surface, in addition to the S atom, on both the order and the feasibility of phase transitions in self-assembled monolayers. To assess the role of an additional O anchor, we have compared the adsorption of two mercaptobenzoic acid isomers, 2-mercaptobenzoic acid (2-MBA) and 4-mercaptobenzoic acid (4-MBA), on Au(111). Results from scanning tunneling microscopy, X-ray photoelectron spectroscopy, electrochemical techniques, and density functional theory calculations show that the additional O anchor in 2-MBA hinders surface mobility, reducing domain size and impeding the molecular reorganization involved in phase transition to denser phases on the Au(111) substrates. This knowledge can help to predict the range order and molecular density of the thiol SAM depending on the chemical structure of the adsorbate.

  4. Hepatic mitochondrial dysfunction induced by fatty acids and ethanol.

    PubMed

    Gyamfi, Daniel; Everitt, Hannah E; Tewfik, Ihab; Clemens, Dahn L; Patel, Vinood B

    2012-12-01

    Understanding the key aspects of the pathogenesis of alcoholic fatty liver disease particularly alterations to mitochondrial function remains to be resolved. The role of fatty acids in this regard requires further investigation due to their involvement in fatty liver disease and obesity. This study aimed to characterize the early effects of saturated and unsaturated fatty acids alone on liver mitochondrial function and during concomitant ethanol exposure using isolated liver mitochondria and VA-13 cells (Hep G2 cells that efficiently express alcohol dehydrogenase). Liver mitochondria or VA-13 cells were treated with increasing concentrations of palmitic or arachidonic acid (1 to 160 μM) for 24 h with or without 100 mM ethanol. The results showed that in isolated liver mitochondria both palmitic and arachidonic acids significantly reduced state 3 respiration in a concentration-dependent manner (P<0.001), implicating their ionophoric activities. Increased ROS production occurred in a dose-dependent manner especially in the presence of rotenone (complex I inhibitor), which was significantly more prominent in arachidonic acid at 80 μM (+970%, P<0.001) than palmitic acid (+40%, P<0.01). In VA-13 cells, ethanol alone and both fatty acids (40 μM) were able to decrease the mitochondrial membrane potential and cellular ATP levels and increase lipid formation. ROS production was significantly increased with arachidonic acid (+110%, P<0.001) exhibiting a greater effect than palmitic acid (+39%, P<0.05). While in the presence of ethanol, the drop in the mitochondrial membrane potential, cellular ATP levels, and increased lipid formation were further enhanced by both fatty acids, but with greater effect in the case of arachidonic acid, which also correlated with significant cytotoxicity (P<0.001). This study confirms the ability of fatty acids to promote mitochondrial injury in the development of alcoholic fatty liver disease.

  5. Development and assessment of an innovative soil-washing process based on the use of cholic acid-derivatives as pollutant-mobilizing agents.

    PubMed

    Berselli, Sara; Benitez, Emilio; Fedi, Stefano; Zannoni, Davide; Medici, Alessandro; Marchetti, Leonardo; Fava, Fabio

    2006-03-05

    Surfactant-aided soil washing is often proposed for the restoration of aged organic pollutant-contaminated soils. As many of commercial surfactants have been found to be toxic and recalcitrant, the opportunity to use in this process cheap, non-toxic, and biodegradable pollutant-mobilizing agents, such as deoxycholic acid (DA), bovine bile (BB), and the residue resulting from DA extraction from BB (BBR), was studied in this work. A soil historically contaminated by chlorinated anilines and benzenes, thiophenes, and several polycyclic aromatic hydrocarbons was suspended at 15% w/v and washed in water or water amended at 1.0% (w/v) with DA, BB, BBR, or Triton X-100 (TX). The resulting effluents were supplemented with nutrients and subjected to aerobic bioremediation. The biogenic agents enhanced the water pollutant elution potential by 230/440%. TX enhanced the same parameter by about 540%; however, it mediated a lower depletion of the initial soil ecotoxicity and a more extensive mobilization of soil constituents with respect to the biogenic agents. Furthermore, TX adversely affected the biotreatability of resulting effluents, by adversely affecting the growth of cultivable bacterial biomass and the structure of eubacterial community of the effluent. On the contrary, the biogenic agents, and in particular DA and BB, enhanced the effluents bioremediation, by sustaining the growth and increasing the complexity of the effluent eubacterial communities. Thus, DA and BB are very promising additives for an effective and environmental friendly soil washing treatment of aged (chloro)organics contaminated soils.

  6. Community mobilization and social marketing to promote weekly iron-folic acid supplementation in women of reproductive age in Vietnam: impact on anemia and iron status.

    PubMed

    Berger, Jacques; Thanh, Hoang Thi Kim; Cavalli-Sforza, Tommaso; Smitasiri, Suttilak; Khan, Nguyen Cong; Milani, Silvano; Hoa, Pham Thuy; Quang, Nguyen Dinh; Viteri, Fernando

    2005-12-01

    The community mobilization and social marketing program promoting a preventive approach of weekly iron-folic acid supplementation in women of reproductive age improved iron status of non-pregnant women in Vietnam. Three to six months of weekly pre-pregnancy supplementation and regular weekly intake of supplements during pregnancy allowed women to achieve good iron and hemoglobin status during the two first trimesters of pregnancy. In the third trimester, iron deficiency and anemia were notably present but low birth weight prevalence was low. This demonstrates the effectiveness and safety of the preventive approach as implemented here to prevent and control iron deficiency and anemia in women of reproductive age before and during pregnancy.

  7. Characterization of chiral amino acids from different milk origins using ultra-performance liquid chromatography coupled to ion-mobility mass spectrometry

    PubMed Central

    Tian, He; Zheng, Nan; Li, Songli; Zhang, Yangdong; Zhao, Shengguo; Wen, Fang; Wang, Jiaqi

    2017-01-01

    Milk contains free amino acids (AAs) that play essential roles in maintaining the growth and health of infants, and D-AA isomers are increasingly being recognized as important signalling molecules. However, there are no studies of the different characteristics of chiral AA (C-AA) from different milk origins. Here, UPLC coupled to ion-mobility high-resolution MS (IM-HRMS) was employed to characterize 18 pairs of C-AAs in human, cow, yak, buffalo, goat, and camel milk. The results proved that milk origins can be differentiated based on the D- to L- AA ratio-based projection scores by principal component analysis. The present study gives a deeper understanding of the D- to L- AA ratio underlying the biological functions of different animal milks, and provide a new strategy for the study of AA metabolic pathways. PMID:28393862