Science.gov

Sample records for acid ffa flux

  1. Pharmacological properties of acid N-thiazolylamide FFA2 agonists

    PubMed Central

    Brown, Andrew J; Tsoulou, Christina; Ward, Emma; Gower, Elaine; Bhudia, Nisha; Chowdhury, Forhad; Dean, Tony W; Faucher, Nicolas; Gangar, Akanksha; Dowell, Simon J

    2015-01-01

    FFA2 is a receptor for short-chain fatty acids. Propionate (C3) and 4-chloro-α-(1-methylethyl)-N-2-thiazolyl-benzeneacetamide (4-CMTB), the prototypical synthetic FFA2 agonist, evoke calcium mobilization in neutrophils and inhibit lipolysis in adipocytes via this G-protein-coupled receptor. 4-CMTB contains an N-thiazolylamide motif but no acid group, and 4-CMTB and C3 bind to different sites on FFA2 and show allosteric cooperativity. Recently, FFA2 agonists have been described that contain both N-thiazolylamide and carboxylate groups, reminiscent of bitopic ligands. These are thought to engage the carboxylate-binding site on FFA2, but preliminary evidence suggests they do not bind to the same site as 4-CMTB even though both contain N-thiazolylamide. Here, we describe the characterization of four FFA2 ligands containing both N-thiazolylamide and carboxylate. (R)-3-benzyl-4-((4-(2-chlorophenyl)thiazol-2-yl)(methyl)amino)-4-oxobutanoic acid (compound 14) exhibits allosteric agonism with 4-CMTB but not C3. Three other compounds agonize FFA2 in [35S]GTPγS-incorporation or cAMP assays but behave as inverse agonists in yeast-based gene-reporter assays, showing orthosteric antagonism of C3 responses but allosteric antagonism of 4-CMTB responses. Thus, the bitopic-like FFA2 ligands engage the orthosteric site but do not compete at the site of 4-CMTB binding on an FFA2 receptor molecule. Compound 14 activates FFA2 on human neutrophils and mouse adipocytes, but appears not to inhibit lipolysis upon treatment of human primary adipocytes in spite of the presence of a functional FFA2 receptor in these cells. Hence, these new ligands may reveal differences in coupling of FFA2 between human and rodent adipose tissues. PMID:26236484

  2. Characterizing pharmacological ligands to study the long-chain fatty acid receptors GPR40/FFA1 and GPR120/FFA4.

    PubMed

    Milligan, G; Alvarez-Curto, E; Watterson, K R; Ulven, T; Hudson, B D

    2015-07-01

    The free fatty acid receptors (FFA) 1 (previously designated GPR40) and FFA4 (previously GPR120) are two GPCRs activated by saturated and unsaturated longer-chain free fatty acids. With expression patterns and functions anticipated to directly or indirectly promote insulin secretion, provide homeostatic control of blood glucose and improve tissue insulin sensitivity, both receptors are being studied as potential therapeutic targets for the control of type 2 diabetes. Furthermore, genetic and systems biology studies in both humans and mouse models link FFA4 receptors to diabetes and obesity. Although activated by the same group of free fatty acids, FFA1 and FFA4 receptors are not closely related and, while the basis of recognition of fatty acids by FFA1 receptors is similar to that of the short-chain fatty acid receptors FFA2 and FFA3, the amino acid residues involved in endogenous ligand recognition by FFA4 receptors are more akin to those of the sphingosine 1 phosphate receptor S1P1 . Screening and subsequent medicinal chemistry programmes have developed a number of FFA1 receptor selective agonists that are effective in promoting insulin secretion in a glucose concentration-dependent manner, and in lowering blood glucose levels. However, the recent termination of Phase III clinical trials employing TAK-875/fasiglifam has caused a setback and raises important questions over the exact nature and mechanistic causes of the problems. Progress in the identification and development of highly FFA4 receptor-selective pharmacological tools has been less rapid and several issues remain to be clarified to fully validate this receptor as a therapeutic target. Despite this, the ongoing development of a range of novel ligands offers great opportunities to further unravel the contributions of these receptors. PMID:25131623

  3. Functions of omega-3 fatty acids and FFA4 (GPR120) in macrophages.

    PubMed

    Im, Dong-Soon

    2016-08-15

    Omega-3 polyunsaturated fatty acids (n-3 PUFAs), which are plentiful in fish oil, have been known for decades to be beneficial functional nutrients in different disease states. GPR120 is a G protein-coupled receptor for long-chain unsaturated fatty acids, including n-3 PUFAs, and was recently renamed free fatty acid receptor 4 (FFA4). Studies on FFA4-deficient mice and the development of specific pharmacological tools have started to unravel the functions of FFA4 associated with the actions of n-3 PUFAs in obesity, type 2 diabetes, and inflammation-related diseases. Here, the state of the art regarding the roles and functions of FFA4 and n-3 PUFA in macrophages are reviewed from the pharmacological perspective. In particular, the functions of n-3 PUFA on the anti-inflammatory M2 phenotypes of macrophages in different organs, such as, adipose tissues and liver, are discussed along with future research directions. PMID:25987421

  4. Synthesis, Activity, and Docking Study of Novel Phenylthiazole-Carboxamido Acid Derivatives as FFA2 Agonists.

    PubMed

    Ma, Liang; Wang, Taijin; Shi, Min; Fu, Ping; Pei, Heying; Ye, Haoyu

    2016-07-01

    Free fatty acid receptor 2 (FFA2), also known as GPR43, is activated by short-chain fatty acids (SCFAs) that are mainly produced by the gut microbiota through the fermentation of undigested carbohydrates and dietary fibers. FFA2 currently appears to be a potential target in the management of obesity, diabetes, inflammatory diseases, and cancer. In the study, a series of novel phenylthiazole-carboxamido acid derivatives has been synthesized and evaluated as potential orthosteric FFA2 ligands for the study of structure-activity relationships. Compound 6e was found to exhibit the twofold potent agonistic activity in the stable hFFA2-transfected CHO-K1 cells (EC50 = 23.1 μm) as that of positive control propionate (EC50 = 43.3 μm). We also reported the results of mutagenesis studies based on the crystal structure of hFFA1 bound to TAK-875 at 2.3 Å resolution to identify important residues for orthosteric agonist 6e inducing FFA2 activation. PMID:26808470

  5. Development and Characterization of a Potent Free Fatty Acid Receptor 1 (FFA1) Fluorescent Tracer.

    PubMed

    Christiansen, Elisabeth; Hudson, Brian D; Hansen, Anders Højgaard; Milligan, Graeme; Ulven, Trond

    2016-05-26

    The free fatty acid receptor 1 (FFA1/GPR40) is a potential target for treatment of type 2 diabetes. Although several potent agonists have been described, there remains a strong need for suitable tracers to interrogate ligand binding to this receptor. We address this by exploring fluorophore-tethering to known potent FFA1 agonists. This led to the development of 4, a high affinity FFA1 tracer with favorable and polarity-dependent fluorescent properties. A close to ideal overlap between the emission spectrum of the NanoLuciferase receptor tag and the excitation spectrum of 4 enabled the establishment of a homogeneous BRET-based binding assay suitable for both detailed kinetic studies and high throughput competition binding studies. Using 4 as a tracer demonstrated that the compound acts fully competitively with selected synthetic agonists but not with lauric acid and allowed for the characterization of binding affinities of a diverse selection of known FFA1 agonists, indicating that 4 will be a valuable tool for future studies at FFA1. PMID:27074625

  6. Structure-Activity Study of Dihydrocinnamic Acids and Discovery of the Potent FFA1 (GPR40) Agonist TUG-469.

    PubMed

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian; Merten, Nicole; Pfleiderer, Michael; Karlsen, Kasper K; Rasmussen, Sanne S; Steensgaard, Mette; Hamacher, Alexandra; Schmidt, Johannes; Drewke, Christel; Petersen, Rasmus Koefoed; Kristiansen, Karsten; Ullrich, Susanne; Kostenis, Evi; Kassack, Matthias U; Ulven, Trond

    2010-10-14

    The free fatty acid 1 receptor (FFA1 or GPR40), which is highly expressed on pancreatic β-cells and amplifies glucose-stimulated insulin secretion, has emerged as an attractive target for the treatment of type 2 diabetes. Several FFA1 agonists containing the para-substituted dihydrocinnamic acid moiety are known. We here present a structure-activity relationship study of this compound family suggesting that the central methyleneoxy linker is preferable for the smaller compounds, whereas the central methyleneamine linker gives higher potency to the larger compounds. The study resulted in the discovery of the potent and selective full FFA1 agonist TUG-469 (29). PMID:24900217

  7. The short-chain fatty acid receptor, FFA2, contributes to gestational glucose homeostasis.

    PubMed

    Fuller, Miles; Priyadarshini, Medha; Gibbons, Sean M; Angueira, Anthony R; Brodsky, Michael; Hayes, M Geoffrey; Kovatcheva-Datchary, Petia; Bäckhed, Fredrik; Gilbert, Jack A; Lowe, William L; Layden, Brian T

    2015-11-15

    The structure of the human gastrointestinal microbiota can change during pregnancy, which may influence gestational metabolism; however, a mechanism of action remains unclear. Here we observed that in wild-type (WT) mice the relative abundance of Actinobacteria and Bacteroidetes increased during pregnancy. Along with these changes, short-chain fatty acids (SCFAs), which are mainly produced through gut microbiota fermentation, significantly changed in both the cecum and peripheral blood throughout gestation in these mice. SCFAs are recognized by G protein-coupled receptors (GPCRs) such as free fatty acid receptor-2 (FFA2), and we have previously demonstrated that the fatty acid receptor-2 gene (Ffar2) expression is higher in pancreatic islets during pregnancy. Using female Ffar2-/- mice, we explored the physiological relevance of signaling through this GPCR and found that Ffar2-deficient female mice developed fasting hyperglycemia and impaired glucose tolerance in the setting of impaired insulin secretion compared with WT mice during, but not before, pregnancy. Insulin tolerance tests were similar in Ffar2-/- and WT mice before and during pregnancy. Next, we examined the role of FFA2 in gestational β-cell mass, observing that Ffar2-/- mice had diminished gestational expansion of β-cells during pregnancy. Interestingly, mouse genotype had no significant impact on the composition of the gut microbiome, but did affect the observed SCFA profiles, suggesting a functional difference in the microbiota. Together, these results suggest a potential link between increased Ffar2 expression in islets and the alteration of circulating SCFA levels, possibly explaining how changes in the gut microbiome contribute to gestational glucose homeostasis. PMID:26394664

  8. Discovery of potent and selective agonists for the free fatty acid receptor 1 (FFA(1)/GPR40), a potential target for the treatment of type II diabetes.

    PubMed

    Christiansen, Elisabeth; Urban, Christian; Merten, Nicole; Liebscher, Kathrin; Karlsen, Kasper K; Hamacher, Alexandra; Spinrath, Andreas; Bond, Andrew D; Drewke, Christel; Ullrich, Susanne; Kassack, Matthias U; Kostenis, Evi; Ulven, Trond

    2008-11-27

    A series of 4-phenethynyldihydrocinnamic acid agonists of the free fatty acid receptor 1 (FFA(1)) has been discovered and explored. The preferred compound 20 (TUG-424, EC(50) = 32 nM) significantly increased glucose-stimulated insulin secretion at 100 nM and may serve to explore the role of FFA(1) in metabolic diseases such as diabetes or obesity. PMID:18947221

  9. Discovery of TUG-770: A Highly Potent Free Fatty Acid Receptor 1 (FFA1/GPR40) Agonist for Treatment of Type 2 Diabetes.

    PubMed

    Christiansen, Elisabeth; Hansen, Steffen V F; Urban, Christian; Hudson, Brian D; Wargent, Edward T; Grundmann, Manuel; Jenkins, Laura; Zaibi, Mohamed; Stocker, Claire J; Ullrich, Susanne; Kostenis, Evi; Kassack, Matthias U; Milligan, Graeme; Cawthorne, Michael A; Ulven, Trond

    2013-05-01

    Free fatty acid receptor 1 (FFA1 or GPR40) enhances glucose-stimulated insulin secretion from pancreatic β-cells and currently attracts high interest as a new target for the treatment of type 2 diabetes. We here report the discovery of a highly potent FFA1 agonist with favorable physicochemical and pharmacokinetic properties. The compound efficiently normalizes glucose tolerance in diet-induced obese mice, an effect that is fully sustained after 29 days of chronic dosing. PMID:23687558

  10. Acid soldering flux poisoning

    MedlinePlus

    The harmful substances in soldering fluxes are called hydrocarbons. They include: Ammonium chloride Rosin Hydrochloric acid Zinc ... Lee DC. Hydrocarbons. In: Marx JA, Hockberger RS, Walls RM, et ... Rosen's Emergency Medicine: Concepts and Clinical Practice . 8th ...

  11. FFA Leadership Handbook.

    ERIC Educational Resources Information Center

    Moody, Sidney B.; Miller, L. E.

    The handbook is designed to assist youth leaders in the Future Farmers of America (FFA). It is organized into nine sections of varying length which consider the following facets of FFA (with sample sub-topics in parentheses): FFA members (things to know to become an effective member, membership policy); FFA officers (duties and qualifications of…

  12. Free fatty acid receptor 1 (FFA1/GPR40) agonists: mesylpropoxy appendage lowers lipophilicity and improves ADME properties.

    PubMed

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian; Grundmann, Manuel; Schröder, Ralf; Hudson, Brian D; Milligan, Graeme; Cawthorne, Michael A; Kostenis, Evi; Kassack, Matthias U; Ulven, Trond

    2012-07-26

    FFA1 (GPR40) is a new target for treatment of type 2 diabetes. We recently identified the potent FFA1 agonist TUG-469 (5). Inspired by the structurally related TAK-875, we explored the effects of a mesylpropoxy appendage on 5. The appendage significantly lowers lipophilicity and improves metabolic stability while preserving potency, resulting in discovery of the potent FFA1 agonist 13. PMID:22724451

  13. Effects of a 3-day fast and of ethanol on splanchnic metabolism of FFA, amino acids, and carbohydrates in healthy young men.

    PubMed Central

    Wolfe, B M; Havel, J R; Marliss, E B; Kane, J P; Seymour, J; Ahuja, S P

    1976-01-01

    Splanchnic metabolism was studied to quantify changes underlying the fatty liver, hyperlipemia, and hypoglycemia produced by ethanol. Four subjects fasted for 15 h were compared with five subjects fasted for 69 h under basal conditions and during continuous intravenous infusion of sufficient ethanol to give a concentration of 3-5 mM in arterial blood plasma. Splanchnic storage of fatty acids was estimated from the difference between uptake of FFA and secretion of derived products. Basal values for splanchnic uptake of FFA were twofold higher after the 69-h fast while splanchnic storage of fatty acids and production of ketone bodies increased threefold. Values for basal secreation into the blood of triglycerides derived from FFA were similar in the two groups. In both nutritional states, the fraction of FFA taken up in the splanchnic region oxidized to ketone bodies and to CO2 fell when ethanol was given because of preferential oxidation of ethanol to acetate, and the fraction esterified rose. However, systemic transport and splanchnic uptake of FFA fell with ethanol in subjects fasted 15 h, so that neither storage of triglycerides in splanchnic tissues nor secretion into the blood increased. In subjects fasted 69 h, ethanol increased transport of FFA and splanchnic storage of fat. In all but one subject it also increased secretion of triglycerides into the blood. The concentration of glucose in blood fell during ethanol infusion in all five subjects undergoing the 69-h fast. Mean splanchnic glucose production was maintained at about one-half of the pre-ethanol value, despite virtual cessation of splanchnic uptake of lactate and of those amino acids that are metabolized via malate. Quantitative estimates of extrasplanchnic metabolism suggest that enhanced formation of alpha-glycerophosphate from glucose, in addition to impaired hepatic gluconeogenesis, may contribute to ethanol-induced hypoglycemia in man. PMID:176179

  14. The Pharmacology of TUG-891, a Potent and Selective Agonist of the Free Fatty Acid Receptor 4 (FFA4/GPR120), Demonstrates Both Potential Opportunity and Possible Challenges to Therapeutic Agonism

    PubMed Central

    Hudson, Brian D.; Shimpukade, Bharat; Mackenzie, Amanda E.; Butcher, Adrian J.; Pediani, John D.; Christiansen, Elisabeth; Heathcote, Helen; Tobin, Andrew B.; Ulven, Trond

    2013-01-01

    TUG-891 [3-(4-((4-fluoro-4′-methyl-[1,1′-biphenyl]-2-yl)methoxy)phenyl)propanoic acid] was recently described as a potent and selective agonist for the long chain free fatty acid (LCFA) receptor 4 (FFA4; previously G protein–coupled receptor 120, or GPR120). Herein, we have used TUG-891 to further define the function of FFA4 and used this compound in proof of principle studies to indicate the therapeutic potential of this receptor. TUG-891 displayed similar signaling properties to the LCFA α-linolenic acid at human FFA4 across various assay end points, including stimulation of Ca2+ mobilization, β-arrestin-1 and β-arrestin-2 recruitment, and extracellular signal-regulated kinase phosphorylation. Activation of human FFA4 by TUG-891 also resulted in rapid phosphorylation and internalization of the receptor. While these latter events were associated with desensitization of the FFA4 signaling response, removal of TUG-891 allowed both rapid recycling of FFA4 back to the cell surface and resensitization of the FFA4 Ca2+ signaling response. TUG-891 was also a potent agonist of mouse FFA4, but it showed only limited selectivity over mouse FFA1, complicating its use in vivo in this species. Pharmacologic dissection of responses to TUG-891 in model murine cell systems indicated that activation of FFA4 was able to mimic many potentially beneficial therapeutic properties previously reported for LCFAs, including stimulating glucagon-like peptide-1 secretion from enteroendocrine cells, enhancing glucose uptake in 3T3-L1 adipocytes, and inhibiting release of proinflammatory mediators from RAW264.7 macrophages, which suggests promise for FFA4 as a therapeutic target for type 2 diabetes and obesity. Together, these results demonstrate both potential but also significant challenges that still need to be overcome to therapeutically target FFA4. PMID:23979972

  15. The pharmacology of TUG-891, a potent and selective agonist of the free fatty acid receptor 4 (FFA4/GPR120), demonstrates both potential opportunity and possible challenges to therapeutic agonism.

    PubMed

    Hudson, Brian D; Shimpukade, Bharat; Mackenzie, Amanda E; Butcher, Adrian J; Pediani, John D; Christiansen, Elisabeth; Heathcote, Helen; Tobin, Andrew B; Ulven, Trond; Milligan, Graeme

    2013-11-01

    TUG-891 [3-(4-((4-fluoro-4'-methyl-[1,1'-biphenyl]-2-yl)methoxy)phenyl)propanoic acid] was recently described as a potent and selective agonist for the long chain free fatty acid (LCFA) receptor 4 (FFA4; previously G protein-coupled receptor 120, or GPR120). Herein, we have used TUG-891 to further define the function of FFA4 and used this compound in proof of principle studies to indicate the therapeutic potential of this receptor. TUG-891 displayed similar signaling properties to the LCFA α-linolenic acid at human FFA4 across various assay end points, including stimulation of Ca²⁺ mobilization, β-arrestin-1 and β-arrestin-2 recruitment, and extracellular signal-regulated kinase phosphorylation. Activation of human FFA4 by TUG-891 also resulted in rapid phosphorylation and internalization of the receptor. While these latter events were associated with desensitization of the FFA4 signaling response, removal of TUG-891 allowed both rapid recycling of FFA4 back to the cell surface and resensitization of the FFA4 Ca²⁺ signaling response. TUG-891 was also a potent agonist of mouse FFA4, but it showed only limited selectivity over mouse FFA1, complicating its use in vivo in this species. Pharmacologic dissection of responses to TUG-891 in model murine cell systems indicated that activation of FFA4 was able to mimic many potentially beneficial therapeutic properties previously reported for LCFAs, including stimulating glucagon-like peptide-1 secretion from enteroendocrine cells, enhancing glucose uptake in 3T3-L1 adipocytes, and inhibiting release of proinflammatory mediators from RAW264.7 macrophages, which suggests promise for FFA4 as a therapeutic target for type 2 diabetes and obesity. Together, these results demonstrate both potential but also significant challenges that still need to be overcome to therapeutically target FFA4. PMID:23979972

  16. Horticulture and the FFA

    ERIC Educational Resources Information Center

    Nelson, Clifford L.

    1975-01-01

    The article offers teachers of vocational horticulture a number of specific suggestions for organizing FFA horticulture chapters that will appeal to urban and suburban students and that will improve the quality of their learning. (AJ)

  17. Theme: FFA Conventions and Contests.

    ERIC Educational Resources Information Center

    Garten, Stacy A.; And Others

    1985-01-01

    Theme articles focus on FFA (Future Farmers of America) conventions and contests. They examine FFA as an extracurricular versus intracurricular activity, keeping competition in perspective, contests as student motivators, how a sponsor views FFA, improving the teaching of leadership, benefits of FFA participation, the needs of disadvantaged and…

  18. Density distribution of free fatty acid receptor 2 (FFA2)-expressing and GLP-1-producing enteroendocrine L cells in human and rat lower intestine, and increased cell numbers after ingestion of fructo-oligosaccharide.

    PubMed

    Kaji, Izumi; Karaki, Shin-Ichiro; Tanaka, Ryo; Kuwahara, Atsukazu

    2011-02-01

    Glucagon-like peptide 1 (GLP-1) is a multifunctional hormone in glucose metabolism and intestinal function released by enteroendocrine L-cells. The plasma concentration of GLP-1 is increased by indigestible carbohydrates and luminal infusion of short-chain fatty acids (SCFAs). However, the triggers and modulators of the GLP-1 release remain unclear. We hypothesized that SCFAs produced by bacterial fermentation are involved in enteroendocrine cell proliferation and hormone release through free fatty acid receptor 2 (FFA2, also known as FFAR2 or GPR43) in the large intestine. Fructo-oligosaccharide (Fructo-OS), fermentable indigestible carbohydrate, was used as a source of SCFAs. Rats were fed an indigestible-carbohydrate-free diet (control) or a 5% Fructo-OS-containing diet for 28 days. FFA2-, GLP-1-, and 5-hydroxytryptamine (5-HT)-positive enteroendocrine cells were quantified immunohistochemically in the colon, cecum, and terminal ileum. The same analysis was performed in surgical specimens from human lower intestine. The coexpression of FFA2 with GLP-1 was investigated both in rats and humans. Fructo-OS supplementation in rats increased the densities of FFA2-positive enteroendocrine cells in rat proximal colon, by over two-fold, relative to control, in parallel with GLP-1-containing L-cells. The segmental distributions of these cells in human were similar to rats fed the control diet. The FFA2-positive enteroendocrine cells were GLP-1-containing L-cells, but not 5-HT-containing EC cells, in both human and rat colon and terminal ileum. Fermentable indigestible carbohydrate increases the number of FFA2-positive L-cells in the proximal colon. FFA2 activation by SCFAs might be an important trigger for produce and release GLP-1 by enteroendocrine L-cells in the lower intestine. PMID:21113792

  19. Community Development--FFA Style.

    ERIC Educational Resources Information Center

    Lee, Jasper S.

    Intended to help Future Farmers of America (FFA) members develop skills in improving their communities under the Building Our American Community Program, this publication provides guidance on how FFA chapter members can be active citizens and use democratic processes. Section I, Identifying and Analyzing Communities, consists of four chapters.…

  20. Loss of FFA2 and FFA3 increases insulin secretion and improves glucose tolerance in type 2 diabetes.

    PubMed

    Tang, Cong; Ahmed, Kashan; Gille, Andreas; Lu, Shun; Gröne, Hermann-Josef; Tunaru, Sorin; Offermanns, Stefan

    2015-02-01

    Type 2 diabetes is a major health problem worldwide, and one of its key features is the inability of elevated glucose to stimulate the release of sufficient amounts of insulin from pancreatic beta cells to maintain normal blood glucose levels. New therapeutic strategies to improve beta cell function are therefore believed to be beneficial. Here we demonstrate that the short-chain fatty acid receptors FFA2 (encoded by FFAR2) and FFA3 (encoded by FFAR3) are expressed in mouse and human pancreatic beta cells and mediate an inhibition of insulin secretion by coupling to Gi-type G proteins. We also provide evidence that mice with dietary-induced obesity and type 2 diabetes, as compared to non-obese control mice, have increased local formation by pancreatic islets of acetate, an endogenous agonist of FFA2 and FFA3, as well as increased systemic levels. This elevation may contribute to the insufficient capacity of beta cells to respond to hyperglycemia in obese states. Indeed, we found that genetic deletion of both receptors, either on the whole-body level or specifically in pancreatic beta cells, leads to greater insulin secretion and a profound improvement of glucose tolerance when mice are on a high-fat diet compared to controls. On the other hand, deletion of Ffar2 and Ffar3 in intestinal cells did not alter glucose tolerance in diabetic animals, suggesting these receptors act in a cell-autonomous manner in beta cells to regulate insulin secretion. In summary, under diabetic conditions elevated acetate acts on FFA2 and FFA3 to inhibit proper glucose-stimulated insulin secretion, and we expect antagonists of FFA2 and FFA3 to improve insulin secretion in type 2 diabetes. PMID:25581519

  1. Relationships among FFA Membership Factors and Vo-Ag Programs in the Eastern FFA Region.

    ERIC Educational Resources Information Center

    Cooper, Elmer L.; Nelson, Clifford L.

    At the request of the Future Farmers of America (FFA), an analysis was conducted of reasons for a decline in membership in 1977-79 after a 40-year period of steady growth. Factors such as the vocational-agriculture teacher shortage, number of chartered FFA chapters, certification status of teachers, FFA membership costs, and contract length of…

  2. FFA Leaders: Personality and Leadership Style.

    ERIC Educational Resources Information Center

    Owings, Jeffrey A.; Nelson, Clifford L.

    Leadership training and recognition of leadership skills have been a cornerstone of the Future Farmers of America (FFA) since its inception. To determine if certain personality characteristics are associated with individuals who hold leadership positions and if the level of leadership reflects particular personality traits, 147 FFA chapter and…

  3. Heterogeneity of FFA responses or multiplexing?

    PubMed Central

    Ross, David A.; McGugin, Rankin W.; Gauthier, Isabel

    2014-01-01

    Recent work using cluster analysis of brain activity during movies revealed distinct clusters that respond to faces and different non-face categories in the fusiform face area (FFA). Because of the limited heterogeneity observed, these results could mean that FFA contains one population of cells capable of representing multiple categories. PMID:24360882

  4. Robust expertise effects in right FFA

    PubMed Central

    McGugin, Rankin Williams; Newton, Allen T; Gore, John C; Gauthier, Isabel

    2015-01-01

    The fusiform face area (FFA) is one of several areas in occipito-temporal cortex whose activity is correlated with perceptual expertise for objects. Here, we investigate the robustness of expertise effects in FFA and other areas to a strong task manipulation that increases both perceptual and attentional demands. With high-resolution fMRI at 7Telsa, we measured responses to images of cars, faces and a category globally visually similar to cars (sofas) in 26 subjects who varied in expertise with cars, in (a) a low load 1-back task with a single object category and (b) a high load task in which objects from two categories rapidly alternated and attention was required to both categories. The low load condition revealed several areas more active as a function of expertise, including both posterior and anterior portions of FFA bilaterally (FFA1/FFA2 respectively). Under high load, fewer areas were positively correlated with expertise and several areas were even negatively correlated, but the expertise effect in face-selective voxels in the anterior portion of FFA (FFA2) remained robust. Finally, we found that behavioral car expertise also predicted increased responses to sofa images but no behavioral advantages in sofa discrimination, suggesting that global shape similarity to a category of expertise is enough to elicit a response in FFA and other areas sensitive to experience, even when the category itself is not of special interest. The robustness of expertise effects in right FFA2 and the expertise effects driven by visual similarity both argue against attention being the sole determinant of expertise effects in extrastriate areas. PMID:25192631

  5. The activation of supraspinal GPR40/FFA1 receptor signalling regulates the descending pain control system

    PubMed Central

    Nakamoto, K; Nishinaka, T; Sato, N; Aizawa, F; Yamashita, T; Mankura, M; Koyama, Y; Kasuya, F; Tokuyama, S

    2015-01-01

    Background and Purpose The ω-3 polyunsaturated fatty acids exert antinociceptive effects in inflammatory and neuropathic pain; however, the underlying mechanisms remain unclear. Docosahexaenoic acid-induced antinociception may be mediated by the orphan GPR40, now identified as the free fatty acid receptor 1 (FFA1 receptor). Here, we examined the involvement of supraspinal FFA1 receptor signalling in the regulation of inhibitory pain control systems consisting of serotonergic and noradrenergic neurons. Experimental Approach Formalin-induced pain behaviours were measured in mice. Antinociception induced by FFA1 receptor agonists was examined by intrathecal injections of a catecholaminergic toxin, 5-HT lowering drug or these antagonists. The expression of FFA1 receptor protein and c-Fos was estimated by immunohistochemistry, and the levels of noradrenaline and 5-HT in the spinal cord were measured by LC-MS/MS. Key Results FFA1 receptors colocalized with NeuN (a neuron marker) in the medulla oblongata and with tryptophan hydroxylase (TPH; a serotonergic neuron marker) and dopamine β-hydroxylase (DBH; a noradrenergic neuron marker). A single i.c.v. injection of GW9508, a FFA1 receptor agonist, increased the number of c-Fos-positive cells and the number of neurons double-labelled for c-Fos and TPH and/or DBH. It decreased formalin-induced pain behaviour. This effect was inhibited by pretreatment with 6-hydroxydopamine, DL-p-chlorophenylalanine, yohimbine or WAY100635. Furthermore, GW9508 facilitated the release of noradrenaline and 5-HT in the spinal cord. In addition, GW1100, a FFA1 receptor antagonist, significantly increased formalin-induced pain-related behaviour. Conclusion and Implications Activation of the FFA1 receptor signalling pathway may play an important role in the regulation of the descending pain control system. PMID:25362997

  6. Learn, Grow, Become. FFA Edition. Second Edition.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This curriculum guide contains seven Future Farmers of America (FFA) units of study for secondary students. The units focus on developing students' potential for leadership, personal growth, and career success through agricultural education. Each of the instructional units includes some or all of the basic components of a unit of instruction:…

  7. Selective FFA2 Agonism Appears to Act via Intestinal PYY to Reduce Transit and Food Intake but Does Not Improve Glucose Tolerance in Mouse Models.

    PubMed

    Forbes, Sarah; Stafford, Stuart; Coope, Gareth; Heffron, Helen; Real, Katia; Newman, Robert; Davenport, Richard; Barnes, Matt; Grosse, Johannes; Cox, Helen

    2015-11-01

    Free fatty acid receptor 2 (FFA2) is expressed on enteroendocrine L cells that release glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) when activated by short-chain fatty acids (SCFAs). Functionally GLP-1 and PYY inhibit gut transit, increase glucose tolerance, and suppress appetite; thus, FFA2 has therapeutic potential for type 2 diabetes and obesity. However, FFA2-selective agonists have not been characterized in vivo. Compound 1 (Cpd 1), a potent FFA2 agonist, was tested for its activity on the following: GLP-1 release, modulation of intestinal mucosal ion transport and transit in wild-type (WT) and FFA2(-/-) tissue, and food intake and glucose tolerance in lean and diet-induced obese (DIO) mice. Cpd 1 stimulated GLP-1 secretion in vivo, but this effect was only detected with dipeptidyl peptidase IV inhibition, while mucosal responses were PYY, not GLP-1, mediated. Gut transit was faster in FFA2(-/-) mice, while Cpd 1 slowed WT transit and reduced food intake and body weight in DIO mice. Cpd 1 decreased glucose tolerance and suppressed plasma insulin in lean and DIO mice, despite FFA2(-/-) mice displaying impaired glucose tolerance. These results suggest that FFA2 inhibits intestinal functions and suppresses food intake via PYY pathways, with limited GLP-1 contribution. Thus, FFA2 may be an effective therapeutic target for obesity but not for type 2 diabetes. PMID:26239054

  8. Oleic acid exposure of cultured endothelial cells alters lipid mediator production

    EPA Science Inventory

    Diesel, biodiesel, and other combustion sources contain free fatty acid (FFA) components capable of entering the body through particulate inhalation. FFA can also be endogenously released into circulation in response to stress. When in circulation, bioactive FFA may interact with...

  9. Factors Influencing or Discouraging Secondary School Students' FFA Participation

    ERIC Educational Resources Information Center

    Phelps, Kirstin; Henry, Anna L.; Bird, William A.

    2012-01-01

    Modern adolescents are faced with a variety of choices regarding how to spend their free time. As recruitment and increased student participation continues to be a major priority of the National FFA Organization, it is essential to explore the reasons why students make the choice to become or not to become a member of FFA. This study was a part of…

  10. State FFA Officers' Confidence and Trustworthiness of Biotechnology Information Sources

    ERIC Educational Resources Information Center

    Wingenbach, Gary J.; Rutherford, Tracy A.

    2007-01-01

    Are state FFA officers' awareness levels of agricultural topics reported in mass media superior to those who do not serve in leadership roles? The purpose of this study was to determine elected state FFA officers' awareness of biotechnology, and their confidence and trust of biotechnology information sources. Descriptive survey methods were used…

  11. Suppression of Autophagic Flux by Bile Acids in Hepatocytes

    PubMed Central

    Kong, Bo; Guo, Grace; Ding, Wen-Xing

    2014-01-01

    Retention of bile acids (BAs) in the liver during cholestasis plays an important role in the development of cholestatic liver injury. Several studies have reported that high concentrations of certain BAs induce cell death and inflammatory response in the liver, and BAs may promote liver tumorigenesis. Macroautophagy (hereafter referred to as autophagy) is a lysosomal degradation process that regulates organelle and protein homeostasis and serves as a cell survival mechanism under a variety of stress conditions. However, it is not known if BAs modulate autophagy in hepatocytes. In the present study, we determined autophagic flux in livers of farnesoid X receptor (FXR) knockout (KO) mice that have increased concentrations of hepatic BAs and in primary cultured mouse hepatocytes treated with BAs. The results showed that autophagic flux was impaired in livers of FXR KO mice and in BA-treated primary mouse hepatocytes. Mechanistically, BAs did not affect the activities of cathepsin or the proteasome, but impaired autophagosomal-lysosomal fusion likely due to reduction of Rab7 protein expression and targeting to autophagosomes. In conclusion, BAs suppress autophagic flux in hepatocytes by impairing autophagosomal-lysosomal fusion, which may be implicated in bile acid-induced liver tumor promotion observed in FXR KO mice. PMID:24189133

  12. Effects of Acute Supramaximal Cycle Exercise on Plasma FFA Concentration in Obese Adolescent Boys

    PubMed Central

    Jabbour, Georges

    2015-01-01

    Aims The aims of the present study are 1) to evaluate the free fatty acid (FFA) profile and 2) to determine the relative anaerobic and aerobic contributions to total energy consumption during repeated supramaximal cycling bouts (SCE) in adolescent boys with different body weight statuses. Materials and Methods Normal-weight (NW), overweight (OW), and obese (OB) adolescent boys (n =15 per group) completed a SCE sessions consisted of 6 x 6s maximal sprints with 2 min of passive rest between each repetition. Plasma FFA levels were determined at rest, immediately after a 10 min warm-up, and immediately at the end of SCE. The anaerobic and aerobic contributions (%) were measured via repeated SCE bouts. Insulin resistance was calculated using the homoeostatic model assessment (HOMA-IR) index. Results The FFA concentrations measured immediately after SCE were higher in the OB group than in the OW and NW (p<0.01 and p<0.01, respectively) groups. Moreover, the anaerobic contributions to SCE were significantly lower in obese adolescents (p<0.01) and decreased significantly during the 2nd, 3rd and 4th repetitions. The FFA levels were significantly associated with the HOMA-IR index and aerobic contribution among adolescent boys (r=0.83 and r=0.91, respectively, p<0.01). Conclusion In contrast to the NW and OW groups, there is an increase in lipid mobilization and sift to aerobic energy metabolism during SCE in the OB group. PMID:26076464

  13. The Contributions of E.M. Tiffany and the FFA Creed to Leadership Development within the FFA

    ERIC Educational Resources Information Center

    Connors, James J.; Velez, Jonathan J.

    2008-01-01

    The FFA Creed by E.M. Tiffany has influenced the lives of countless FFA members. However, the creed has received little attention in terms of its origin. A creed is a foundational component for many organizations. It serves to establish collective vision and goals with the intent of providing purpose and direction to the individual as well as the…

  14. An Examination of Middle School Agricultural Education and FFA Programs: Survey Results from State FFA Executive Secretaries.

    ERIC Educational Resources Information Center

    Rossetti, Rosemarie; McCaslin, N. L.

    A study collected information from 52 of the 53 state Future Farmers of America (FFA) executive secretaries who were sent questionnaires on middle school student enrollment in agricultural education and membership in the national FFA organization. Results showed that 30 states have agricultural education programs in the middle school level, with a…

  15. Instantaneous characterization of vegetable oils via TAG and FFA profiles by easy ambient sonic-spray ionization mass spectrometry.

    PubMed

    Simas, Rosineide C; Catharino, Rodrigo R; Cunha, Ildenize B S; Cabral, Elaine C; Barrera-Arellano, Daniel; Eberlin, Marcos N; Alberici, Rosana M

    2010-04-01

    A fast and reliable method is presented for the analysis of vegetable oils. Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is shown to efficiently desorb and ionize the main oil constituents from an inert surface under ambient conditions and to provide comprehensive triacylglyceride (TAG) and free fatty acid (FFA) profiles detected mainly as either [TAG + Na](+) or [FFA-H](-) ions. EASI(+/-)-MS analysis is simple, easily implemented, requires just a tiny droplet of the oil and is performed without any pre-separation or chemical manipulation. It also causes no fragmentation of TAG ions hence diacylglyceride (DAG) and monoacylglyceride (MAG) profiles and contents can also be measured. The EASI(+/-)-MS profiles of TAG and FFA permit authentication and quality control and can be used, for instance, to access levels of adulteration, acidity, oxidation or hydrolysis of vegetable oils in general. PMID:20349539

  16. Meeting record for FFA working meeting of November 15, 1991

    SciTech Connect

    Stejskal, G.F.

    1992-01-03

    This document provides a meeting record of the Federal Facility Agreement (FFA) working meeting to discuss progress on old issues and further required actions regarding environmental impacts of the Savannah River Facility. (FI)

  17. Increased levels of FFA during passive heat loading after a 2-week repeated heat load in Koreans

    NASA Astrophysics Data System (ADS)

    Lee, Jeong Beom; Kim, Tae Wook

    2015-04-01

    The purpose of this study was to determine whether repeated heat load is closely related to circulating levels of free fatty acids (FFA) during repeated passive heat loading (PHL), defined as immersion of the lower body up to an umbilical level in hot water, 42 ± 0.5 °C (three times/week, 30 min/day) for 2 weeks. There were significant correlations between mean body temperature and FFA before and after repeated heat load ( p < 0.001, respectively), and the level of FFA was significantly higher after repeated heat load during PHL ( p < 0.01). The threshold of mean body temperature for lipolysis was lowered by repeated heat load and enhanced lipolysis during PHL. However, caution is needed for diabetic individuals.

  18. Winning the War: A Historical Analysis of the FFA during World War II

    ERIC Educational Resources Information Center

    Wolf, Kattlyn J.; Connors, James J.

    2009-01-01

    The United States' participation in World War II affected millions of men, women, and children, both at home and around the world. The war effort also affected the Future Farmers of America (FFA). FFA members, agriculture teachers, and national FFA officers all volunteered to serve their country during the war. Local FFA chapters and individual…

  19. Evidence for dissolution of fatty acids in sediment traps: Impact on flux estimates

    NASA Astrophysics Data System (ADS)

    KöRtzinger, Arne; Schulz-Bull, Detlef E.; Petrick, Gert; Duinker, Jan C.

    1994-02-01

    The effect of dissolution from particulates into the supernatant solution in sediment trap sample cups has been measured for fatty acids. A mooring array with time series sediment traps was deployed in the northeast Atlantic Ocean (59°N, 21°W) for 14 months. Selected representative samples from the trap at 2200 m (poisoned with NaN3) were analyzed for total and free fatty acids in both the solution and particulate phase by means of gas chromatography-mass spectrometry with an ion trap detector. The flux contribution of the dissolved total fatty acids (∑ DTFA) was found to be between 15 and 75% of the total flux (∑ TTFA, sum of the fluxes of total fatty acids in both particles and supernatants). Dissolved free fatty acids (∑ DFFA) represented 25-88% of the total flux of free fatty acids (∑ TFFA). Absolute concentrations of total and free fatty acids in both compartments are discussed in terms of the processes controlling the distribution between the two phases, for example, readsorption. Sample handling, poisoning, bacterial activity, and swimmers may also affect fatty acid distribution. Flux data (sum of particulate and dissolved fluxes) are presented for individual fatty acids. Also, the degree of dissolution of individual fatty acids is shown for one sample (dissolved fraction ranging between 16 and 98% of total flux).

  20. Occupational Aspirations of State FFA Contest and Award Winners.

    ERIC Educational Resources Information Center

    Bowen, Blannie E.; Doerfert, David L.

    1989-01-01

    A study explored the occupational aspirations of 300 (of 503) students with high levels of participation in Future Farmers of America's (FFA) Computers in Agriculture (CIA), Proficiency Award (PA), and Prepared and Extemporaneous Speaking (PES) contests. CIA and PES winners aspired to professional occupations more than PA winners. PES winners…

  1. Identifying Quality Indicators of SAE and FFA: A Delphi Approach

    ERIC Educational Resources Information Center

    Jenkins, Charles Cordell, III; Kitchel, Tracy

    2009-01-01

    The purpose of this study was to determine quality indicators for SAE and FFA according to 36 experts across the United States. This is a part of a larger study looking at all components of the traditional three-circle model. The study utilized the Delphi technique to garner expert opinion about quality indicators in Agricultural Education. For…

  2. CHEMICAL FLUX IN AN ACID-STRESSED STREAM

    EPA Science Inventory

    The acidity of rain and snow falling on widely separated areas of the world has been increasing during the past 30 yr (refs 1-3). Acid rainfall consists of a dilute solution of sulphuric and nitric acids due to the oxidation and hydrolysis of airborne sulphur and nitrogen and fre...

  3. Official FFA Manual for the National Organization for Students of Vocational Agriculture.

    ERIC Educational Resources Information Center

    Future Farmers of America, Washington, DC.

    Topics covered in the 1975 Future Farmers of America (FFA) official manual are: a historical sketch of the organization, a description of the FFA organization, the national FFA center, national constitution and bylaws, the eight essentials of a good chapter, organizing a local chapter, chapter program activities, chapter meetings, parliamentary…

  4. ADAPTING THE FFA TO A CHANGING PROGRAM OF VOCATIONAL AGRICULTURE. RESEARCH SERIES IN AGRICULTURAL EDUCATION.

    ERIC Educational Resources Information Center

    KANTER, EARL F.; BENDER, RALPH E.

    THE PURPOSE OF THIS NATIONAL STUDY WAS TO SUGGEST WAYS OF ADAPTING THE FUTURE FARMERS OF AMERICA (FFA) TO A CHANGING PROGRAM OF VOCATIONAL AGRICULTURE THROUGH IDENTIFYING NEW PURPOSES OF THE FFA AND EVALUATING SELECTED OPERATIONAL GUIDELINES AND NATIONAL AND STATE FFA ACTIVITIES. MEMBERS OF THE UNITED STATES OFFICE OF EDUCATION, HEAD STATE…

  5. Glucose metabolic flux distribution of Lactobacillus amylophilus during lactic acid production using kitchen waste saccharified solution

    PubMed Central

    Liu, Jianguo; Wang, Qunhui; Zou, Hui; Liu, Yingying; Wang, Juan; Gan, Kemin; Xiang, Juan

    2013-01-01

    The 13C isotope tracer method was used to investigate the glucose metabolic flux distribution and regulation in Lactobacillus amylophilus to improve lactic acid production using kitchen waste saccharified solution (KWSS). The results demonstrate that L. amylophilus is a homofermentative bacterium. In synthetic medium, 60.6% of the glucose entered the Embden–Meyerhof–Parnas (EMP) to produce lactic acid, whereas 36.4% of the glucose entered the pentose phosphate metabolic pathway (HMP). After solid–liquid separation of the KWSS, the addition of Fe3+ during fermentation enhanced the NADPH production efficiency and increased the NADH content. The flux to the EMP was also effectively increased. Compared with the control (60.6% flux to EMP without Fe3+ addition), the flux to the EMP with the addition of Fe3+ (74.3%) increased by 23.8%. In the subsequent pyruvate metabolism, Fe3+ also increased lactate dehydrogenase activity, and inhibited alcohol dehydrogenase, pyruvate dehydrogenase and pyruvate carboxylase, thereby increasing the lactic acid production to 9.03 g l−1, an increase of 8% compared with the control. All other organic acid by-products were lower than in the control. However, the addition of Zn2+ showed an opposite effect, decreasing the lactic acid production. In conclusion it is feasible and effective means using GC-MS, isotope experiment and MATLAB software to integrate research the metabolic flux distribution of lactic acid bacteria, and the results provide the theoretical foundation for similar metabolic flux distribution. PMID:23489617

  6. Determination of SFC, FFA, and equivalent reaction time for enzymatically interestified oils using NIRS.

    PubMed

    Houmøller, Lars P; Kristensen, Dorthe; Rosager, Helle

    2007-02-15

    The use of near infrared spectroscopy (NIRS) for rapid determination of the degree of interesterification of blends of palm stearin, coconut oil, and rapeseed oil obtained using an immobilized Thermomyces lanuginosa lipase at 70 degrees C was investigated. Interesterification was carried out by applying both fixed bed and batch reactors. Calibrations were developed for quantitative determination of solid fat content (SFC) at 10, 20, 30, 35, and 40 degrees C and free fatty acid (FFA) resulting in root mean square errors of prediction of 1.0, 1.3, 1.4, 1.6, 1.7, and 0.19% (w/w), respectively. The data showed that NIRS could be used to replace the traditional methods for determining FFA and SFC in vegetable oils. It was possible to monitor the activity of the immobilized enzyme for interesterification of margarine oils by predicting the equivalent reaction time in a batch reactor from NIR spectra. Root mean square errors of prediction for two different oil blends interesterified for 300 and 170min were 21 and 12min, respectively. PMID:19071387

  7. Bile Acid Flux Is Necessary for Normal Liver Regeneration

    PubMed Central

    Naugler, Willscott E.

    2014-01-01

    Background & Aims Many signals governing liver regeneration (LR) following 2/3 partial hepatectomy (PH) are recognized, but the primary signal(s) remains unknown. The aim of the study was to confirm that the remnant liver after PH lacks capacity to secrete the BA pool returning via the enterohepatic ciruculation (EHC), which may in turn stimulate LR. Methods After standard PH, BA flux was documented and BA signaling (Fgf15) and synthesis (Cyp7a) determined by qPCR. Rat biliary fistula (BF) and Asbt knockout mouse models interrupted the EHC prior to PH, and standard assays for LR employed along with complete RNA sequencing. CCl4 intoxication after BF tested the hypothesis in an alternate injury model. Results BA rise in systemic blood immediately following PH, confirming that the remnant liver cannot handle the BA returning via portal circulation. When the BA pool is drained prior to PH in the rat BF model, LR is markedly attenuated, a phenomenon reversed with duodenal BA replacement. Hepatocyte proliferation is similarly attenuated after PH in the Asbt knockout mouse as well as after CCl44 intoxication in rats with BF. Complete RNA sequencing in the rat PH model shows that early c-jun and AP-1 gene expression pathways are down regulated in the absence of BA, coincident with attenuated LR. Conclusions Absent BA return to the liver after PH or CCl4 injury markedly attenuates LR, though hepatocyte proliferation still occurs, inferring that BA flux and signaling are not the sole signals governing LR. Transcriptional networks involving c-jun and AP-1 are involved in the BA-specific effects on hepatocyte proliferation. PMID:24841254

  8. Amino Acid Flux from Metabolic Network Benefits Protein Translation: the Role of Resource Availability

    PubMed Central

    Hu, Xiao-Pan; Yang, Yi; Ma, Bin-Guang

    2015-01-01

    Protein translation is a central step in gene expression and affected by many factors such as codon usage bias, mRNA folding energy and tRNA abundance. Despite intensive previous studies, how metabolic amino acid supply correlates with protein translation efficiency remains unknown. In this work, we estimated the amino acid flux from metabolic network for each protein in Escherichia coli and Saccharomyces cerevisiae by using Flux Balance Analysis. Integrated with the mRNA expression level, protein abundance and ribosome profiling data, we provided a detailed description of the role of amino acid supply in protein translation. Our results showed that amino acid supply positively correlates with translation efficiency and ribosome density. Moreover, with the rank-based regression model, we found that metabolic amino acid supply facilitates ribosome utilization. Based on the fact that the ribosome density change of well-amino-acid-supplied genes is smaller than poorly-amino-acid-supply genes under amino acid starvation, we reached the conclusion that amino acid supply may buffer ribosome density change against amino acid starvation and benefit maintaining a relatively stable translation environment. Our work provided new insights into the connection between metabolic amino acid supply and protein translation process by revealing a new regulation strategy that is dependent on resource availability. PMID:26056817

  9. Glucose metabolic flux distribution of Lactobacillus amylophilus during lactic acid production using kitchen waste saccharified solution.

    PubMed

    Liu, Jianguo; Wang, Qunhui; Zou, Hui; Liu, Yingying; Wang, Juan; Gan, Kemin; Xiang, Juan

    2013-11-01

    The (13) C isotope tracer method was used to investigate the glucose metabolic flux distribution and regulation in Lactobacillus amylophilus to improve lactic acid production using kitchen waste saccharified solution (KWSS). The results demonstrate that L. amylophilus is a homofermentative bacterium. In synthetic medium, 60.6% of the glucose entered the Embden-Meyerhof-Parnas (EMP) to produce lactic acid, whereas 36.4% of the glucose entered the pentose phosphate metabolic pathway (HMP). After solid-liquid separation of the KWSS, the addition of Fe(3+) during fermentation enhanced the NADPH production efficiency and increased the NADH content. The flux to the EMP was also effectively increased. Compared with the control (60.6% flux to EMP without Fe(3+) addition), the flux to the EMP with the addition of Fe(3+) (74.3%) increased by 23.8%. In the subsequent pyruvate metabolism, Fe(3+) also increased lactate dehydrogenase activity, and inhibited alcohol dehydrogenase, pyruvate dehydrogenase and pyruvate carboxylase, thereby increasing the lactic acid production to 9.03 g l(-1) , an increase of 8% compared with the control. All other organic acid by-products were lower than in the control. However, the addition of Zn(2+) showed an opposite effect, decreasing the lactic acid production. In conclusion it is feasible and effective means using GC-MS, isotope experiment and MATLAB software to integrate research the metabolic flux distribution of lactic acid bacteria, and the results provide the theoretical foundation for similar metabolic flux distribution. PMID:23489617

  10. FFA-induced hepatic insulin resistance in vivo is mediated by PKCδ, NADPH oxidase, and oxidative stress.

    PubMed

    Pereira, Sandra; Park, Edward; Mori, Yusaku; Haber, C Andrew; Han, Ping; Uchida, Toyoyoshi; Stavar, Laura; Oprescu, Andrei I; Koulajian, Khajag; Ivovic, Alexander; Yu, Zhiwen; Li, Deling; Bowman, Thomas A; Dewald, Jay; El-Benna, Jamel; Brindley, David N; Gutierrez-Juarez, Roger; Lam, Tony K T; Najjar, Sonia M; McKay, Robert A; Bhanot, Sanjay; Fantus, I George; Giacca, Adria

    2014-07-01

    Fat-induced hepatic insulin resistance plays a key role in the pathogenesis of type 2 diabetes in obese individuals. Although PKC and inflammatory pathways have been implicated in fat-induced hepatic insulin resistance, the sequence of events leading to impaired insulin signaling is unknown. We used Wistar rats to investigate whether PKCδ and oxidative stress play causal roles in this process and whether this occurs via IKKβ- and JNK-dependent pathways. Rats received a 7-h infusion of Intralipid plus heparin (IH) to elevate circulating free fatty acids (FFA). During the last 2 h of the infusion, a hyperinsulinemic-euglycemic clamp with tracer was performed to assess hepatic and peripheral insulin sensitivity. An antioxidant, N-acetyl-L-cysteine (NAC), prevented IH-induced hepatic insulin resistance in parallel with prevention of decreased IκBα content, increased JNK phosphorylation (markers of IKKβ and JNK activation, respectively), increased serine phosphorylation of IRS-1 and IRS-2, and impaired insulin signaling in the liver without affecting IH-induced hepatic PKCδ activation. Furthermore, an antisense oligonucleotide against PKCδ prevented IH-induced phosphorylation of p47(phox) (marker of NADPH oxidase activation) and hepatic insulin resistance. Apocynin, an NADPH oxidase inhibitor, prevented IH-induced hepatic and peripheral insulin resistance similarly to NAC. These results demonstrate that PKCδ, NADPH oxidase, and oxidative stress play a causal role in FFA-induced hepatic insulin resistance in vivo and suggest that the pathway of FFA-induced hepatic insulin resistance is FFA → PKCδ → NADPH oxidase and oxidative stress → IKKβ/JNK → impaired hepatic insulin signaling. PMID:24824652

  11. Free-fatty acid receptor-4 (GPR120): Cellular and molecular function and its role in metabolic disorders.

    PubMed

    Moniri, Nader H

    2016-06-15

    Over the last decade, a subfamily of G protein-coupled receptors that are agonized by endogenous and dietary free-fatty acids (FFA) has been discovered. These free-fatty acid receptors include FFA2 and FFA3, which are agonized by short-chained FFA, as well as FFA1 and FFA4, which are agonized by medium-to-long chained FFA. Ligands for FFA1 and FFA4 comprise the family of long chain polyunsaturated omega-3 fatty acids including α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), suggesting that many of the long-known beneficial effects of these fats may be receptor mediated. In this regard, FFA4 has gathered considerable interest due to its role in ameliorating inflammation, promoting insulin sensitization, and regulating energy metabolism in response to FFA ligands. The goal of this review is to summarize the body of evidence in regard to FFA4 signal transduction, its mechanisms of regulation, and its functional role in a variety of tissues. In addition, recent endeavors toward discovery of small molecules that modulate FFA4 activity are also presented. PMID:26827942

  12. Carbon fluxes in an acid rain impacted boreal headwater catchment

    NASA Astrophysics Data System (ADS)

    Marx, Anne; Hintze, Simone; Jankovec, Jakub; Sanda, Martin; Dusek, Jaromir; Vogel, Tomas; van Geldern, Robert; Barth, Johannes A. C.

    2016-04-01

    Terrestrial carbon export via inland aquatic systems is a key process in the budget of the global carbon cycle. This includes loss of carbon to the atmosphere via gas evasion from rivers or reservoirs as well as carbon fixation in freshwater sediments. Headwater streams are the first endmembers of the transition of carbon between soils, groundwater and surface waters and the atmosphere. In order to quantify these processes the experimental catchment Uhlirska (1.78 km2) located in the northern Czech Republic was studied. Dissolved inorganic, dissolved organic and particulate organic carbon (DIC, DOC, POC) concentrations and isotopes were analyzed in ground-, soil -and stream waters between 2014 and 2015. In addition, carbon dioxide degassing was quantified via a stable isotope modelling approach. Results show a discharge-weighted total carbon export of 31.99 g C m‑2 yr‑1 of which CO2 degassing accounts 79 %. Carbon isotope ratios (δ13C) of DIC, DOC, and POC (in ‰ VPDB) ranged from -26.6 to -12.4 ‰ from -29.4 to -22.7 ‰ and from -30.6 to -26.6 ‰ respectively. The mean values for DIC are -21.8 ±3.8 ‰ -23.6 ±0.9 ‰ and -19.5 ±3.0 ‰ for soil, shallow ground and surface water compartments. For DOC, these compartments have mean values of -27.1 ±0.3 ‰ -27.0 ±0.8 ‰ and -27.4 ±0.7 ‰Ṁean POC value of shallow groundwaters and surface waters are -28.8 ±0.8 ‰ and -29.3 ±0.5 ‰ respectively. These isotope ranges indicate little turnover of organic material and predominant silicate weathering. The degassing of CO2 caused an enrichment of the δ13C-DIC values of up to 6.8 ‰ between a catchment gauge and the catchment outlet over a distance of 866 m. In addition, the Uhlirska catchment has only negligible natural sources of sulphate, yet SO42‑ accounts for 21 % of major stream water ions. This is most likely a remainder from acid rain impacts in the area.

  13. Engineering oilseeds for sustainable production of industrial and nutritional feedstocks: solving bottlenecks in fatty acid flux.

    PubMed

    Cahoon, Edgar B; Shockey, Jay M; Dietrich, Charles R; Gidda, Satinder K; Mullen, Robert T; Dyer, John M

    2007-06-01

    Oilseeds provide a unique platform for the production of high-value fatty acids that can replace non-sustainable petroleum and oceanic sources of specialty chemicals and aquaculture feed. However, recent efforts to engineer the seeds of crop and model plant species to produce new types of fatty acids, including hydroxy and conjugated fatty acids for industrial uses and long-chain omega-3 polyunsaturated fatty acids for farmed fish feed, have met with only modest success. The collective results from these studies point to metabolic 'bottlenecks' in the engineered plant seeds that substantially limit the efficient or selective flux of unusual fatty acids between different substrate pools and ultimately into storage triacylglycerol. Evidence is emerging that diacylglycerol acyltransferase 2, which catalyzes the final step in triacylglycerol assembly, is an important contributor to the synthesis of unusual fatty acid-containing oils, and is likely to be a key target for future oilseed metabolic engineering efforts. PMID:17434788

  14. A Status Report on Middle Grade Agricultural Education and FFA Programs in the United States.

    ERIC Educational Resources Information Center

    Rossetti, Rosemarie; McCaslin, N. L.

    1994-01-01

    Census of 52 Future Farmers of America (FFA) executive secretaries found the following: 30 states have middle-grade agricultural education; 19 have middle-grade FFA membership; 14 have a core agriculture curriculum; 17 have state-level competitions; most do not favor national middle-grade competitions; and few disadvantages apart from potential…

  15. Predicting Youth Leadership Life Skills Development among FFA Members in Arizona, Colorado, and New Mexico.

    ERIC Educational Resources Information Center

    Dormody, Thomas J.; Seevers, Brenda S.

    1994-01-01

    From 3 states, 256 usable responses from 400 Future Farmers of America (FFA) members showed that achievement expectancy was positively related to youth leadership life skills development. Females had higher leadership skills development. Leadership skills were not related to self-esteem, years in FFA, age, ethnicity, or place of residence. (SK)

  16. Bridging Horizons. An Advisor's Guide to FFA Involvement for Members with Disabilities.

    ERIC Educational Resources Information Center

    Ploss, Adrienne J.; Field, William E.; Frick, Martin J.

    This guide is designed to provide Future Farmers of America (FFA) advisors with information to assist them in their efforts to include all youth in FFA, including those with disabilities. It addresses benefits of involving youth with disabilities and federal, state, and local legislation and regulations concerning people with disabilities.…

  17. Fitting Vo-Ag and FFA Together Best for Students and Teachers.

    ERIC Educational Resources Information Center

    Snyder, H. Leon

    1979-01-01

    The Future Farmers of America (FFA) is more than a leadership development organization and when used as an intracurricular activity, it can serve as a teaching tool. The FFA adds advantages to the program in areas such as supervised experience, award motivation, providing real world experience, public relations, travel, and competition. (LRA)

  18. Engaging Hispanic Students in Agricultural Education and the FFA: A 3-Year Case Study

    ERIC Educational Resources Information Center

    Roberts, T. Grady; Hall, Johnathan L.; Briers, Gary E.; Gill, Ernie; Shinn, Glen C.; Larke, Alvin, Jr.; Jaure, Paul

    2009-01-01

    This article describes the outcomes of field-based efforts to increase diversity in agricultural education programs and the FFA. This study focused on three schools in San Antonio, Texas. Guided by Rogers' (2003) theories of diffusion of innovations, a series of six intervention strategies was implemented: (a) provide specific FFA or agricultural…

  19. Metabolic carbon fluxes and biosynthesis of polyhydroxyalkanoates in Ralstonia eutropha on short chain fatty acids.

    PubMed

    Yu, Jian; Si, Yingtao

    2004-01-01

    Short chain fatty acids such as acetic, propionic, and butyric acids can be synthesized into polyhydroxyalkanoates (PHAs) by Ralstonia eutropha. Metabolic carbon fluxes of the acids in living cells have significant effect on the yield, composition, and thermomechanical properties of PHA bioplastics. Based on the general knowledge of central metabolism pathways and the unusual metabolic pathways in R. eutropha, a metabolic network of 41 bioreactions is constructed to analyze the carbon fluxes on utilization of the short chain fatty acids. In fed-batch cultures with constant feeding of acid media, carbon metabolism and distribution in R. eutropha were measured involving CO2, PHA biopolymers, and residual cell mass. As the cells underwent unsteady state metabolism and PHA biosynthesis under nitrogen-limited conditions, accumulative carbon balance was applied for pseudo-steady-state analysis of the metabolic carbon fluxes. Cofactor NADP/NADPH balanced between PHA synthesis and the C3/C4 pathway provided an independent constraint for solution of the underdetermined metabolic network. A major portion of propionyl-CoA was directed to pyruvate via the 2-methylcitrate cycle and further decarboxylated to acetyl-CoA. Only a small amount of propionate carbon (<15% carbon) was directly condensed with acetyl-CoA for 3-hydroxyvalerate. The ratio of glyoxylate shunt to TCA cycle varies from 0 to 0.25, depending on the intracellular acetyl-CoA level and acetic acid in the medium. Malate is the node of the C3/C4 pathway and TCA cycle and its decarboxylation to dehydrogenation ranges from 0.33 to 1.28 in response to the demands on NADPH and oxaloacetate for short chain fatty acids utilization. PMID:15296425

  20. Free fatty acids chain length distribution affects the permeability of skin lipid model membranes.

    PubMed

    Uchiyama, Masayuki; Oguri, Masashi; Mojumdar, Enamul H; Gooris, Gert S; Bouwstra, Joke A

    2016-09-01

    The lipid matrix in the stratum corneum (SC) plays an important role in the barrier function of the skin. The main lipid classes in this lipid matrix are ceramides (CERs), cholesterol (CHOL) and free fatty acids (FFAs). The aim of this study was to determine whether a variation in CER subclass composition and chain length distribution of FFAs affect the permeability of this matrix. To examine this, we make use of lipid model membranes, referred to as stratum corneum substitute (SCS). We prepared SCS containing i) single CER subclass with either a single FFA or a mixture of FFAs and CHOL, or ii) a mixture of various CER subclasses with either a single FFA or a mixture of FFAs and CHOL. In vitro permeation studies were performed using ethyl-p-aminobenzoic acid (E-PABA) as a model drug. The flux of E-PABA across the SCS containing the mixture of FFAs was higher than that across the SCS containing a single FA with a chain length of 24 C atoms (FA C24), while the E-PABA flux was not effected by the CER composition. To select the underlying factors for the changes in permeability, the SCSs were examined by Fourier transform infrared spectroscopy (FTIR) and Small angle X-ray scattering (SAXS). All lipid models demonstrated a similar phase behavior. However, when focusing on the conformational ordering of the individual FFA chains, the shorter chain FFA (with a chain length of 16, 18 or 20 C atoms forming only 11m/m% of the total FFA level) had a higher conformational disordering, while the conformational ordering of the chains of the CER and FA C24 and FA C22 hardly did not change irrespective of the composition of the SCS. In conclusion, the conformational mobility of the short chain FFAs present only at low levels in the model SC lipid membranes has a great impact on the permeability of E-PABA. PMID:27287726

  1. Composition and flux of particulate amino acids and chloropigments in equatorial Pacific seawater and sediments

    NASA Astrophysics Data System (ADS)

    Lee, Cindy; Wakeham, Stuart G.; Hedges, John I.

    2000-08-01

    Compositions and fluxes of amino acids and major chloropigments were measured in the central equatorial Pacific Ocean as part of the US JGOFS EqPac program. Fluxes decreased by several orders of magnitude, from 400 to 0.03 mg amino acid m -2 d -1 and from 9 mg to 0.0004 μg chloropigment m -2 d -1, between production in the surface waters and accumulation at the sea floor. Most rapid losses were in surface waters and at the sediment interface. Losses from the mid-water column were as great as those in surface waters or at the sediment interface, but occurred over a much greater depth range. Export flux estimates based on floating sediment traps were higher near the equator and decreased poleward, similar to primary production. Little meridional difference was apparent in composition of either amino acids or pigments in exported material over the 24° of latitude sampled in spite of the large (factor of 5-6) difference in fluxes. However, pigment composition changed dramatically with depth in the water column, and considerable diagenesis occurred before particles reached the sediment. Pigment compositions suggest that suspended particles were more degraded in the northern than in the southern hemisphere, possibly due to differences in food chain structure. Compositional changes in amino acids occurred in the water column, but were most noticeable at the sediment-seawater interface. Increases in the relative proportions of aspartic acid and glycine with depth were more consistent with preferential preservation within the particulate matrix than with any inherent stability of these compounds to heterotrophic consumption. The contribution of amino acids and pigments to total organic carbon clearly shows that selective degradation of organic matter occurs with depth; this is not evident from total organic carbon data alone. Amino acids contributed about a quarter of the total organic carbon (OC) in surface waters and 16% of the OC in sediment; pigments decreased from 1

  2. Processes and fluxes during the initial stage of acid sulfate soil formation

    NASA Astrophysics Data System (ADS)

    Gröger, J.; Hamer, K.; Schulz, H. D.

    2009-04-01

    Acid sulfate soils occur over a wide range of climatic zones, mainly in coastal landscapes. In these soils, the release of sulfuric acid by the oxidation of pyrite generates a very acidic environment (e.g., DENT and PONS, 1995, PONS, 1973). Two major types of acid sulfate soils can be distinguished: In actual acid sulfate soils, the initially contained pyrite was at least partly oxidized. This resulted in a severe acidification of the soil. Potential acid sulfate soils are generally unoxidized and contain large amounts of pyrite. Upon oxidation, these soils will turn into actual acid sulfate soils. By excavation or lowering of the groundwater table, potential acid sulfate soils can be exposed to atmospheric oxygen. During oxidation the pH drops sharply to values below pH 4. This acidification promotes the release of various metals, e.g., alumina, iron and heavy metals. Additionally, large quantities of sulfate are released. In order to assess the effects of disturbances of potential acid sulfate soils, for example by excavations during construction works, several large scale column experiments were conducted with various types of potential acid sulfate soils from Northern Germany. In these experiments, the oxidation and initial profile development of pyritic fen peats and thionic fluvisols were studied over a period of 14 months. The study focused on leaching and the translocation of various metals in the soil profile. To study mobilization processes, element fluxes and the progress of acidification, soil water and leachate were analyzed for total element concentrations. Furthermore, several redox-sensitive parameters, e.g., Fe2+ and sulfide, were measured and changes to the initial solid phase composition were analyzed. Chemical equilibria calculations of the soil water were used to gain insights into precipitation processes of secondary products of pyrite oxidation and leaching products. The results of this study will support the assessment of risks deriving from

  3. Particulate matter fluxes in the southern and central Kara Sea compared to sediments: Bulk fluxes, amino acids, stable carbon and nitrogen isotopes, sterols and fatty acids

    NASA Astrophysics Data System (ADS)

    Gaye, Birgit; Fahl, Kirsten; Kodina, Lyudmila A.; Lahajnar, Niko; Nagel, Birgit; Unger, Daniela; Gebhardt, A. Catalina

    2007-12-01

    The Kara Sea is one of the arctic marginal seas strongly influenced by fresh water and river suspension. The highly seasonal discharge by the two major rivers Yenisei and Ob induces seasonal changes in hydrography, sea surface temperature, ice cover, primary production and sedimentation. In order to obtain a seasonal pattern of sedimentation in the Kara Sea, sediment traps were deployed near the river mouth of the Yenisei (Yen) as well as in the central Kara Sea (Kara) within the framework of the German-Russian project "Siberian River run-off; SIRRO". Two and a half years of time-series flux data were obtained between September 2000 and April 2003 and were analyzed for bulk components, amino acids, stable carbon and nitrogen isotopes as well as sterols and fatty acids. Sediment trap data show that much of the annual deposition occurred under ice cover, possibly enhanced by zooplanktonic activity and sediment resuspension. An early bloom of ice-associated algae in April/May occurred in the polynya area and may have been very important to sustain the life cycles of higher organisms after the light limitation of the winter months due to no/low insolation and ice cover. The strong river input dominated the months June-August in the southern part of the Kara Sea. The central Kara Sea had a much shorter productive period starting in August and was less affected by the river plumes. Despite different time-scales of sampling and trapping biases, total annual fluxes from traps were in the same order of magnitude as accumulation rates in surface sediments. Terrestrial organic carbon accumulation decreased from 10.7 to 0.3 g C m -2 a -1 from the riverine source to the central Kara Sea. Parallel to this, preservation of marine organic matter decreased from 10% to 2% of primary productivity which was probably related to decreasing rates of sedimentation.

  4. Phosphorus limitation strategy to increase propionic acid flux towards 3-hydroxyvaleric acid monomers in Cupriavidus necator.

    PubMed

    Grousseau, Estelle; Blanchet, Elise; Déléris, Stéphane; Albuquerque, Maria G E; Paul, Etienne; Uribelarrea, Jean-Louis

    2014-02-01

    Properties of polyhydroxybutyrate-co-hydroxyvalerate (P(3HB-co-3HV)) depend on their 3HV content. 3HV can be produced by Cupriavidus necator from propionic acid. Few studies explored carbon distribution and dynamics of 3HV and 3HB monomers production, and none of them have been done with phosphorus as limiting nutrient. In this study, fed-batch cultures of C. necator with propionic acid, as sole carbon source or mixed with butyric acid, were performed. Phosphorus deficiency allowed sustaining 3HV production rate and decreasing 3HB production rate, leading to an instant production of up to 100% of 3HV. When a residual growth is sustained by a phosphorus feeding, the maximum 3HV percentage produced from propionic acid is limited to 33% (Mole.Mole(-1)). The association of a second carbon source like butyric acid lead to higher conversion of propionic acid into 3HV. This study showed the importance of the limiting nutrient and of the culture strategy to get the appropriate product. PMID:24365742

  5. Individual differences in FFA activity suggest independent processing at different spatial scales.

    PubMed

    Gauthier, Isabel; Curby, Kim M; Skudlarski, Pawel; Epstein, Russell A

    2005-06-01

    The brain processes images at different spatial scales, but it is unclear how far into the visual stream different scales remain segregated. Using functional magnetic resonance imaging, we found evidence that BOLD activity in the fusiform face area (FFA) reflects computations based on separate spatial frequency inputs. When subjects perform different tasks (attend location vs. identity; attend whole vs. parts) or the same task with different stimuli (upright or inverted) with high- and low-pass images of cars and faces, individual differences in the FFA in one condition are correlated with those in the other condition. However, FFA activity in response to low-pass stimuli is independent of its response to high-pass stimuli. These results suggest that spatial scales are not integrated before the FFA and that processing in this area could support the flexible use of different sources of information present in broad-pass images. PMID:16180628

  6. Fluxes of Nitrous Acid (HONO) above an Agricultural Field Side near Paris

    NASA Astrophysics Data System (ADS)

    Laufs, S.; Cazaunau, M.; Stella, P.; Loubet, B.; Kurtenbach, R.; Cellier, P.; Mellouki, W.; Kleffmann, J.

    2012-04-01

    HONO is an important precursor of the OH radical, the detergent of the atmosphere. Field measurements show high diurnal HONO mixing ratios that cannot be explained by chemical models with known gas phase chemistry. Therefore, daytime sources of HONO are still under discussion. During the last decade many experimental investigation were performed to study heterogeneous production of HONO like the photo enhanced reduction of NO2 on humic acids or photolysis of HNO3 on surfaces. Recently, nitrite produced by bacteria, present in soil, was discussed as a source of HONO as well. In addition gas phase sources like the photolysis of nitrophenols, or the reaction of excited NO2 are discussed. Gradient measurements show high mixing ratios of HONO even above the boundary layer. However, beside intensive investigations on the sources of HONO, it is still an open question whether heterogeneous or gas phase sources are more important in the atmosphere. Flux measurements could represent a method to find the origin of missing sources of HONO. Until now instruments are not sensitive and fast enough to do Eddy correlation measurements for HONO. Alternatively, HONO fluxes are estimated by the Aerodynamic Gradient (AGM), or Relaxed Eddy Accumulation (REA) methods. Here we present HONO fluxes estimated by AGM and the LOPAP technique (Long Path Absorption Photometer) above an agricultural field in Grignon, Paris (48°51'N, 1°58'E). Fluxes during different seasons and different types of vegetations including bare soil will be presented and compared with chemical corrected fluxes of NO, NO2 and O3, or other parameters.

  7. Flux Balance Analysis of Mycolic Acid Pathway: Targets for Anti-Tubercular Drugs

    PubMed Central

    Raman, Karthik; Rajagopalan, Preethi; Chandra, Nagasuma

    2005-01-01

    Mycobacterium tuberculosis is the focus of several investigations for design of newer drugs, as tuberculosis remains a major epidemic despite the availability of several drugs and a vaccine. Mycobacteria owe many of their unique qualities to mycolic acids, which are known to be important for their growth, survival, and pathogenicity. Mycolic acid biosynthesis has therefore been the focus of a number of biochemical and genetic studies. It also turns out to be the pathway inhibited by front-line anti-tubercular drugs such as isoniazid and ethionamide. Recent years have seen the emergence of systems-based methodologies that can be used to study microbial metabolism. Here, we seek to apply insights from flux balance analyses of the mycolic acid pathway (MAP) for the identification of anti-tubercular drug targets. We present a comprehensive model of mycolic acid synthesis in the pathogen M. tuberculosis involving 197 metabolites participating in 219 reactions catalysed by 28 proteins. Flux balance analysis (FBA) has been performed on the MAP model, which has provided insights into the metabolic capabilities of the pathway. In silico systematic gene deletions and inhibition of InhA by isoniazid, studied here, provide clues about proteins essential for the pathway and hence lead to a rational identification of possible drug targets. Feasibility studies using sequence analysis of the M. tuberculosis H37Rv and human proteomes indicate that, apart from the known InhA, potential targets for anti-tubercular drug design are AccD3, Fas, FabH, Pks13, DesA1/2, and DesA3. Proteins identified as essential by FBA correlate well with those previously identified experimentally through transposon site hybridisation mutagenesis. This study demonstrates the application of FBA for rational identification of potential anti-tubercular drug targets, which can indeed be a general strategy in drug design. The targets, chosen based on the critical points in the pathway, form a ready shortlist

  8. Synthesis and regulation of chlorogenic acid in potato: Rerouting phenylpropanoid flux in HQT-silenced lines.

    PubMed

    Payyavula, Raja S; Shakya, Roshani; Sengoda, Venkatesan G; Munyaneza, Joseph E; Swamy, Prashant; Navarre, Duroy A

    2015-05-01

    Chlorogenic acid (CGA) is the major phenolic sink in potato tubers and can constitute over 90% of total phenylpropanoids. The regulation of CGA biosynthesis in potato and the role of the CGA biosynthetic gene hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase (HQT) was characterized. A sucrose induced accumulation of CGA correlated with the increased expression of phenylalanine ammonia-lyase (PAL) rather than HQT. Transient expression of the potato MYB transcription factor StAN1 (anthocyanin 1) in tobacco increased CGA. RNAi suppression of HQT resulted in over a 90% reduction in CGA and resulted in early flowering. The reduction in total phenolics and antioxidant capacity was less than the reduction in CGA, suggesting flux was rerouted into other phenylpropanoids. Network analysis showed distinct patterns in different organs, with anthocyanins and phenolic acids showing negative correlations in leaves and flowers and positive in tubers. Some flavonols increased in flowers, but not in leaves or tubers. Anthocyanins increased in flowers and showed a trend to increase in leaves, but not tubers. HQT suppression increased biosynthesis of caffeoyl polyamines, some of which are not previously reported in potato. Decreased PAL expression and enzyme activity was observed in HQT suppressed lines, suggesting the existence of a regulatory loop between CGA and PAL. Electrophysiology detected no effect of CGA suppression on potato psyllid feeding. Collectively, this research showed that CGA in potatoes is synthesized through HQT and HQT suppression altered phenotype and redirected phenylpropanoid flux. PMID:25421386

  9. A hybrid SVM-FFA method for prediction of monthly mean global solar radiation

    NASA Astrophysics Data System (ADS)

    Shamshirband, Shahaboddin; Mohammadi, Kasra; Tong, Chong Wen; Zamani, Mazdak; Motamedi, Shervin; Ch, Sudheer

    2016-07-01

    In this study, a hybrid support vector machine-firefly optimization algorithm (SVM-FFA) model is proposed to estimate monthly mean horizontal global solar radiation (HGSR). The merit of SVM-FFA is assessed statistically by comparing its performance with three previously used approaches. Using each approach and long-term measured HGSR, three models are calibrated by considering different sets of meteorological parameters measured for Bandar Abbass situated in Iran. It is found that the model (3) utilizing the combination of relative sunshine duration, difference between maximum and minimum temperatures, relative humidity, water vapor pressure, average temperature, and extraterrestrial solar radiation shows superior performance based upon all approaches. Moreover, the extraterrestrial radiation is introduced as a significant parameter to accurately estimate the global solar radiation. The survey results reveal that the developed SVM-FFA approach is greatly capable to provide favorable predictions with significantly higher precision than other examined techniques. For the SVM-FFA (3), the statistical indicators of mean absolute percentage error (MAPE), root mean square error (RMSE), relative root mean square error (RRMSE), and coefficient of determination ( R 2) are 3.3252 %, 0.1859 kWh/m2, 3.7350 %, and 0.9737, respectively which according to the RRMSE has an excellent performance. As a more evaluation of SVM-FFA (3), the ratio of estimated to measured values is computed and found that 47 out of 48 months considered as testing data fall between 0.90 and 1.10. Also, by performing a further verification, it is concluded that SVM-FFA (3) offers absolute superiority over the empirical models using relatively similar input parameters. In a nutshell, the hybrid SVM-FFA approach would be considered highly efficient to estimate the HGSR.

  10. A hybrid SVM-FFA method for prediction of monthly mean global solar radiation

    NASA Astrophysics Data System (ADS)

    Shamshirband, Shahaboddin; Mohammadi, Kasra; Tong, Chong Wen; Zamani, Mazdak; Motamedi, Shervin; Ch, Sudheer

    2015-05-01

    In this study, a hybrid support vector machine-firefly optimization algorithm (SVM-FFA) model is proposed to estimate monthly mean horizontal global solar radiation (HGSR). The merit of SVM-FFA is assessed statistically by comparing its performance with three previously used approaches. Using each approach and long-term measured HGSR, three models are calibrated by considering different sets of meteorological parameters measured for Bandar Abbass situated in Iran. It is found that the model (3) utilizing the combination of relative sunshine duration, difference between maximum and minimum temperatures, relative humidity, water vapor pressure, average temperature, and extraterrestrial solar radiation shows superior performance based upon all approaches. Moreover, the extraterrestrial radiation is introduced as a significant parameter to accurately estimate the global solar radiation. The survey results reveal that the developed SVM-FFA approach is greatly capable to provide favorable predictions with significantly higher precision than other examined techniques. For the SVM-FFA (3), the statistical indicators of mean absolute percentage error (MAPE), root mean square error (RMSE), relative root mean square error (RRMSE), and coefficient of determination (R 2) are 3.3252 %, 0.1859 kWh/m2, 3.7350 %, and 0.9737, respectively which according to the RRMSE has an excellent performance. As a more evaluation of SVM-FFA (3), the ratio of estimated to measured values is computed and found that 47 out of 48 months considered as testing data fall between 0.90 and 1.10. Also, by performing a further verification, it is concluded that SVM-FFA (3) offers absolute superiority over the empirical models using relatively similar input parameters. In a nutshell, the hybrid SVM-FFA approach would be considered highly efficient to estimate the HGSR.

  11. Extraction, purification, methylation and GC-MS analysis of short-chain carboxylic acids for metabolic flux analysis.

    PubMed

    Tivendale, Nathan D; Jewett, Erin M; Hegeman, Adrian D; Cohen, Jerry D

    2016-08-15

    Dynamic metabolic flux analysis requires efficient and effective methods for extraction, purification and analysis of a plethora of naturally-occurring compounds. One area of metabolism that would be highly informative to study using metabolic flux analysis is the tricarboxylic acid (TCA) cycle, which consists of short-chain carboxylic acids. Here, we describe a newly-developed method for extraction, purification, derivatization and analysis of short-chain carboxylic acids involved in the TCA cycle. The method consists of snap-freezing the plant material, followed by maceration and a 12-15h extraction at -80 °C. The extracts are then subject to reduction (to stabilize β-keto acids), purified by strong anion exchange solid phase extraction and methylated with methanolic HCl. This method could also be readily adapted to quantify many other short-chain carboxylic acids. PMID:27348709

  12. Low to middle tropospheric profiles and biosphere/troposphere fluxes of acidic gases in the summertime Canadian taiga

    NASA Technical Reports Server (NTRS)

    Klemm, O.; Talbot, R. W.; Fitzgerald, D. R.; Klemm, K. I.; Lefer, B. L.

    1994-01-01

    We report features of acidic gases in the troposphere from 9 to 5000 m altitude above ground over the Canadian taiga in the summer of 1990. The measurements were conducted at a 30-m meteorological tower and from the NASA Wallops Electra aircraft as part of the joint U.S.-Canadian Arctic Boundary Layer Expedition (ABLE) 3B Northern Wetland Studies (NOWES). We sampled air for acidic gases using the mist chamber collector coupled with subsequent analysis using ion chromatography. At the tower we collected samples at two heights during a 13-day period, including diurnal studies. Using eddy flux and profile data, we estimated the biosphere/troposphere fluxes of nitric, formic, and acetic acids and sulfur dioxide. For the organic acids, emissions from the taiga in the afternoon hours and deposition during the predawn morning hours were observed. The flux intensities alone were however not high enough to explain the observed changes in mixing ratios. The measured deposition fluxes of nitric acid were high enough to have a significant influence on its mixing ratio in the boundary layer. On three days we measured vertical profiles of nitric, formic, and acetic acids through the lower to midtroposphere. We found that the chemical composition of the troposphere was extremely heterogenous. Pronounced layers of polluted air were readily apparent from our measurements. Local photochemical production and episodic long-range transport of trace components, originating from biomass burning and possibly industrial emissions, appear to have a strong influence on the composition of the troposphere and biosphere/troposphere fluxes of acidic gases at this site.

  13. Leadership and Personal Development Abilities Possessed by High School Seniors Who Are FFA Members in Superior FFA Chapters, Non-Superior Chapters, and by Seniors Who Were Never Enrolled in Vocational Agriculture.

    ERIC Educational Resources Information Center

    Ricketts, Samuel Clifton

    The purpose of this study was to describe the leadership and personal development abilities possessed by four groups of male high school seniors. These groups were those high school seniors who participated in high quality (superior) Future Farmers of America (FFA) chapters and low quality (non-superior) FFA chapters and those from schools with…

  14. Flux balance analysis of mixed microbial cultures: application to the production of polyhydroxyalkanoates from complex mixtures of volatile fatty acids.

    PubMed

    Pardelha, Filipa; Albuquerque, Maria G E; Reis, Maria A M; Dias, João M L; Oliveira, Rui

    2012-12-31

    Fermented agro-industrial wastes are potential low cost substrates for polyhydroxyalkanoates (PHA) production by mixed microbial cultures (MMC). The use of complex substrates has however profound implications in the PHA metabolism. In this paper we investigate PHA accumulation using a lumped metabolic model that describes PHA storage from arbitrary mixtures of volatile fatty acids (VFA). Experiments were conducted using synthetic and complex VFA mixtures obtained from the fermentation of sugar cane molasses. Metabolic flux analysis (MFA) and flux balance analysis (FBA) were performed at different stages of culture enrichment in order to investigate the effect of VFA composition and time of enrichment in PHA storage efficiency. Substrate uptake and PHA storage fluxes increased over enrichment time by 70% and 73%, respectively. MFA calculations show that higher PHA storage fluxes are associated to an increase in the uptake of VFA with even number of carbon atoms and a more effective synthesis of hydroxyvalerate (HV) precursors from VFA with odd number of carbons. Furthermore, FBA shows that the key metabolic objective of a MMC subjected to the feast and famine regimen is the minimization of the tricarboxylic acid cycle fluxes. The PHA flux and biopolymer composition (hydroxybutyrate (HB): HV) could be accurately predicted in several independent experiments. PMID:23036926

  15. A Nationwide Examination of Middle School Enrollment in Agricultural Education and Membership in the National FFA Organization.

    ERIC Educational Resources Information Center

    Rossetti, Rosemarie; And Others

    The purpose of this study was to determine the status of middle and junior high school agricultural education and FFA (Future Farmers of America) programs. In spring 1991. questionnaires were sent to all state FFA Executive Secretaries (n=53); 52 returned questionnaires. Three teachers in each of 9 states identified as having middle or junior high…

  16. Determining the Impact of Block Scheduling on Leadership Involvement in the FFA

    ERIC Educational Resources Information Center

    Dunigan, Anne H.; Hoover, Tracy S.

    2007-01-01

    Block scheduling was established in response to educational reform measures and is the restructuring of the school day in longer class increments with fewer number of classes per day. The FFA, an intra-curricular component of the agricultural education, provides leadership opportunities and involvement within the classroom setting. This study…

  17. Career Development, Supervised Agricultural Experience, and FFA. The Connecticut Vocational Agriculture Education Curriculum.

    ERIC Educational Resources Information Center

    Mannebach, Alfred J.; And Others

    This curriculum guide was developed to help teachers and administrators in Connecticut Regional Vocational Agriculture Centers to update and upgrade their vocational agriculture curriculum in the areas of career development, supervised agricultural experience (SAE), and Future Farmers of America (FFA). The curriculum incorporates the competencies…

  18. Spillover of Fatty Acids During Dietary Fat Storage in Type 2 Diabetes

    PubMed Central

    Almandoz, Jaime P.; Singh, Ekta; Howell, Lisa A.; Grothe, Karen; Vlazny, Danielle T.; Smailovic, Almira; Irving, Brian A.; Nelson, Robert H.; Miles, John M.

    2013-01-01

    Spillover of lipoprotein lipase-generated fatty acids from chylomicrons into the plasma free fatty acid (FFA) pool is an important source of FFA and reflects inefficiency in dietary fat storage. We measured spillover in 13 people with type 2 diabetes using infusions of a [3H]triolein-labeled lipid emulsion and [U-13C]oleate during continuous feeding, before and after weight loss. Body fat was measured with dual energy X-ray absorptiometry and computed tomography. Participants lost ∼14% of body weight. There was an ∼38% decrease in meal-suppressed FFA concentration (P < 0.0001) and an ∼23% decrease in oleate flux (P = 0.007). Fractional spillover did not change (P = NS). At baseline, there was a strong negative correlation between spillover and leg fat (r = −0.79, P = 0.001) and a positive correlation with the trunk-to-leg fat ratio (R = 0.56, P = 0.047). These correlations disappeared after weight loss. Baseline leg fat (R = −0.61, P = 0.027) but not trunk fat (R = −0.27, P = 0.38) negatively predicted decreases in spillover with weight loss. These results indicate that spillover, a measure of inefficiency in dietary fat storage, is inversely associated with lower body fat in type 2 diabetes. PMID:23349503

  19. Solder Flux Residues and Humidity-Related Failures in Electronics: Relative Effects of Weak Organic Acids Used in No-Clean Flux Systems

    NASA Astrophysics Data System (ADS)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-04-01

    This paper presents the results of humidity testing of weak organic acids (WOAs), namely adipic, succinic, glutaric, dl-malic, and palmitic acids, which are commonly used as activators in no-clean solder fluxes. The study was performed under humidity conditions varying from 60% relative humidity (RH) to ˜99%RH at 25°C. The following parameters were used for characterization of WOAs: mass gain due to water adsorption and deliquescence of the WOA (by quartz crystal microbalance), resistivity of the water layer formed on the printed circuit board (by impedance spectroscopy), and leakage current measured using the surface insulation resistance pattern in the potential range from 0 V to 10 V. The combined results indicate the importance of the WOA chemical structure for the water adsorption and therefore conductive water layer formation on the printed circuit board assembly (PCBA). A substantial increase of leakage currents and probability of electrochemical migration was observed at humidity levels above the RH corresponding to the deliquescence point of WOAs present as contaminants on the printed circuit boards. The results suggest that use of solder fluxes with WOAs having higher deliquescence point could improve the reliability of electronics operating under circumstances in which exposure to high humidity is likely to occur.

  20. Physiological effects of free fatty acid production in genetically engineered Synechococcus elongatus PCC 7942.

    PubMed

    Ruffing, Anne M; Jones, Howland D T

    2012-09-01

    The direct conversion of carbon dioxide into biofuels by photosynthetic microorganisms is a promising alternative energy solution. In this study, a model cyanobacterium, Synechococcus elongatus PCC 7942, is engineered to produce free fatty acids (FFA), potential biodiesel precursors, via gene knockout of the FFA-recycling acyl-ACP synthetase and expression of a thioesterase for release of the FFA. Similar to previous efforts, the engineered strains produce and excrete FFA, but the yields are too low for large-scale production. While other efforts have applied additional metabolic engineering strategies in an attempt to boost FFA production, we focus on characterizing the engineered strains to identify the physiological effects that limit cell growth and FFA synthesis. The strains engineered for FFA-production show reduced photosynthetic yields, chlorophyll-a degradation, and changes in the cellular localization of the light-harvesting pigments, phycocyanin and allophycocyanin. Possible causes of these physiological effects are also identified. The addition of exogenous linolenic acid, a polyunsaturated FFA, to cultures of S. elongatus 7942 yielded a physiological response similar to that observed in the FFA-producing strains with only one notable difference. In addition, the lipid constituents of the cell and thylakoid membranes in the FFA-producing strains show changes in both the relative amounts of lipid components and the degree of saturation of the fatty acid side chains. These changes in lipid composition may affect membrane integrity and structure, the binding and diffusion of phycobilisomes, and the activity of membrane-bound enzymes including those involved in photosynthesis. Thus, the toxicity of unsaturated FFA and changes in membrane composition may be responsible for the physiological effects observed in FFA-producing S. elongatus 7942. These issues must be addressed to enable the high yields of FFA synthesis necessary for large-scale biofuel

  1. Rainwater trifluoroacetic acid (TFA) in Guangzhou, South China: levels, wet deposition fluxes and source implication.

    PubMed

    Wang, Qiaoyun; Wang, Xinming; Ding, Xiang

    2014-01-15

    The origin of trifluoroacetic acid (TFA) occurring in hydrosphere has long been a controversial issue. Hydrochlorofluorocarbons and hydrofluorocarbons (HCFCs/HFCs) as replacements of chlorofluorocarbons (CFCs) are precursors of TFA in the atmosphere, their contribution to rainwater TFA is a concern as their ambient mixing ratios are continually growing. Here we present rainwater TFA monitored from April 2007 to March 2008 in urban Guangzhou, a central city in south China's highly industrialized and densely populated Pearl River Delta region. Rainwater TFA levels ranged 45.8-974 ng L(-1) with a median of 166 ng L(-1). TFA levels negatively correlated with rainfall amount, the yearly rainfall-weighted average for TFA was 152 ng L(-1). The annual TFA wet deposition flux was estimated to be 229 g km(-2) yr(-1), and the total wet deposition of TFA reached ~1.7 tyr(-1) in Guangzhou. The Two-Box model was applied to estimate attributions of HCFCs/HFCs and fluoropolymers to rainwater TFA assuming TFA generated was proportional to gross domestic product (GDP), gross industrial product (GIP) or number of private cars. The results revealed that the degradation of HCFCs/HFCs and fluoropolymers could explain 131.5-152.4 ng L(-1) rainwater TFA, quite near the observed rainfall-weighted annual mean of 152 ng L(-1), suggesting rainwater TFA in Guangzhou was predominantly originated from these anthropogenic precursors. HCFCs/HFCs accounted for 83.3-96.5% of rainwater TFA observed, while fluoropolymers' contributions were minor (~5%). HFC-134a alone could explain 55.9-90.0% of rainwater TFA, and its contribution would be greatly enhanced with its wide use in mobile air conditioning systems and rapid increase in ambient mixing ratios. PMID:24035981

  2. FFA-ROS-P53-mediated mitochondrial apoptosis contributes to reduction of osteoblastogenesis and bone mass in type 2 diabetes mellitus

    PubMed Central

    Li, Jun; He, Wang; Liao, Bo; Yang, Jingyue

    2015-01-01

    This study evaluated the association between free fatty acid (FFA), ROS generation, mitochondrial dysfunction and bone mineral density (BMD) in type 2 diabetic patients and investigated the molecular mechanism. db/db and high fat (HF)-fed mice were treated by Etomoxir, an inhibitor of CPT1, MitoQ, and PFT-α, an inhibitor of P53. Bone metabolic factors were assessed and BMSCs were isolated and induced to osteogenic differentiation. FFA, lipid peroxidation and mtDNA copy number were correlated with BMD in T2DM patients. Etomoxir, MitoQ and PFT-α significantly inhibited the decrease of BMD and bone breaking strength in db/db and HF-fed mice and suppressed the reduction of BMSCs-differentiated osteoblasts. Etomoxir and MitoQ, but not PFT-α, inhibited the increase of mitochondrial ROS generation in db/db and HF-fed mice and osteoblasts. In addition, Etomoxir, MitoQ and PFT-α significantly inhibited mitochondrial dysfunction in osteoblasts. Moreover, mitochondrial apoptosis was activated in osteoblasts derived from db/db and HF-fed mice, which was inhibited by Etomoxir, MitoQ and PFT-α. Furthermore, mitochondrial accumulation of P53 recruited Bax and initiated molecular events of apoptotic events. These results demonstrated that fatty acid oxidation resulted in ROS generation, activating P53/Bax-mediated mitochondrial apoptosis, leading to reduction of osteogenic differentiation and bone loss in T2DM. PMID:26226833

  3. Redirection of metabolic flux for high levels of omega-7 monounsaturated fatty acid accumulation in camelina seeds.

    PubMed

    Nguyen, Huu Tam; Park, Hyunwoo; Koster, Karen L; Cahoon, Rebecca E; Nguyen, Hanh T M; Shanklin, John; Clemente, Thomas E; Cahoon, Edgar B

    2015-01-01

    Seed oils enriched in omega-7 monounsaturated fatty acids, including palmitoleic acid (16:1∆9) and cis-vaccenic acid (18:1∆11), have nutraceutical and industrial value for polyethylene production and biofuels. Existing oilseed crops accumulate only small amounts (<2%) of these novel fatty acids in their seed oils. We demonstrate a strategy for enhanced production of omega-7 monounsaturated fatty acids in camelina (Camelina sativa) and soybean (Glycine max) that is dependent on redirection of metabolic flux from the typical ∆9 desaturation of stearoyl (18:0)-acyl carrier protein (ACP) to ∆9 desaturation of palmitoyl (16:0)-acyl carrier protein (ACP) and coenzyme A (CoA). This was achieved by seed-specific co-expression of a mutant ∆9-acyl-ACP and an acyl-CoA desaturase with high specificity for 16:0-ACP and CoA substrates, respectively. This strategy was most effective in camelina where seed oils with ~17% omega-7 monounsaturated fatty acids were obtained. Further increases in omega-7 fatty acid accumulation to 60-65% of the total fatty acids in camelina seeds were achieved by inclusion of seed-specific suppression of 3-keto-acyl-ACP synthase II and the FatB 16:0-ACP thioesterase genes to increase substrate pool sizes of 16:0-ACP for the ∆9-acyl-ACP desaturase and by blocking C18 fatty acid elongation. Seeds from these lines also had total saturated fatty acids reduced to ~5% of the seed oil versus ~12% in seeds of nontransformed plants. Consistent with accumulation of triacylglycerol species with shorter fatty acid chain lengths and increased monounsaturation, seed oils from engineered lines had marked shifts in thermotropic properties that may be of value for biofuel applications. PMID:25065607

  4. Improved Free Fatty Acid Production in Cyanobacteria with Synechococcus sp. PCC 7002 as Host

    PubMed Central

    Ruffing, Anne M.

    2014-01-01

    Microbial free fatty acids (FFAs) have been proposed as a potential feedstock for renewable energy. The ability to directly convert carbon dioxide into FFAs makes cyanobacteria ideal hosts for renewable FFA production. Previous metabolic engineering efforts using the cyanobacterial hosts Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have demonstrated this direct conversion of carbon dioxide into FFAs; however, FFA yields in these hosts are limited by the negative impact of FFA production on the host cell physiology. This work investigates the use of Synechococcus sp. PCC 7002 as a cyanobacterial host for FFA production. In comparison to S. elongatus PCC 7942, Synechococcus sp. PCC 7002 strains produced and excreted FFAs at similar concentrations but without the detrimental effects on host physiology. The enhanced tolerance to FFA production with Synechococcus sp. PCC 7002 was found to be temperature-dependent, with physiological effects such as reduced photosynthetic yield and decreased photosynthetic pigments observed at higher temperatures. Additional genetic manipulations were targeted for increased FFA production, including thioesterases and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Overexpression of non-native RuBisCO subunits (rbcLS) from a psbAI promoter resulted in more than a threefold increase in FFA production, with excreted FFA concentrations reaching >130 mg/L. This work illustrates the importance of host strain selection for cyanobacterial biofuel production and demonstrates that the FFA tolerance of Synechococcus sp. PCC 7002 can allow for high yields of excreted FFA. PMID:25152890

  5. Improved Free Fatty Acid Production in Cyanobacteria with Synechococcus sp. PCC 7002 as Host.

    PubMed

    Ruffing, Anne M

    2014-01-01

    Microbial free fatty acids (FFAs) have been proposed as a potential feedstock for renewable energy. The ability to directly convert carbon dioxide into FFAs makes cyanobacteria ideal hosts for renewable FFA production. Previous metabolic engineering efforts using the cyanobacterial hosts Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 have demonstrated this direct conversion of carbon dioxide into FFAs; however, FFA yields in these hosts are limited by the negative impact of FFA production on the host cell physiology. This work investigates the use of Synechococcus sp. PCC 7002 as a cyanobacterial host for FFA production. In comparison to S. elongatus PCC 7942, Synechococcus sp. PCC 7002 strains produced and excreted FFAs at similar concentrations but without the detrimental effects on host physiology. The enhanced tolerance to FFA production with Synechococcus sp. PCC 7002 was found to be temperature-dependent, with physiological effects such as reduced photosynthetic yield and decreased photosynthetic pigments observed at higher temperatures. Additional genetic manipulations were targeted for increased FFA production, including thioesterases and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). Overexpression of non-native RuBisCO subunits (rbcLS) from a psbAI promoter resulted in more than a threefold increase in FFA production, with excreted FFA concentrations reaching >130 mg/L. This work illustrates the importance of host strain selection for cyanobacterial biofuel production and demonstrates that the FFA tolerance of Synechococcus sp. PCC 7002 can allow for high yields of excreted FFA. PMID:25152890

  6. Cardiac lipoprotein lipase activity in the hypertrophied heart may be regulated by fatty acid flux

    PubMed Central

    Hauton, David; Caldwell, Germaine M.

    2012-01-01

    Cardiac hypertrophy is characterised by an imbalance between lipid uptake and fatty acid β-oxidation leading to an accumulation of lipids, particularly triacylglycerol (TAG). It is unclear whether uptake mechanisms such as lipoprotein lipase (LPL) can be attenuated to diminish this uptake. Rats were cold acclimated to induce cardiac hypertrophy and increase cardiac LPL. Lipid uptake and metabolism were altered by feeding a ‘Western-style’ high fat diet (WSD) or feeding oxfenicine (2 g/L) in the drinking water. Diastolic stiffness (increased volume change/unit pressure change) was induced in hypertrophied hearts for rats fed WSD (P < 0.05) or WSD + oxfenicine (P < 0.01), although absolute performance of cardiac muscle, estimated from stress–strain calculations was unchanged. Cold acclimation increased cardiac endothelial LPL (P < 0.05) but this was diminished following oxfenicine. Following WSD LPL was further decreased below WSD-fed control hearts (P < 0.05) with no further decrease by oxfenicine supplementation. A negative correlation was noted between plasma TAG and endothelial LPL (correlation coefficient = − 0.654; P < 0.001) but not cardiac TAG concentration. Transcript levels of angiopoietin-like protein-4 (ANGPTL4) were increased 6-fold by WSD (P < 0.05) and increased 15-fold following WSD + oxfenicine (P < 0.001). For CA-hearts fed WSD or WSD + oxfenicine ANGPTL4 mRNA levels were preserved at chow-fed levels. VLDLR protein levels were increased 10-fold (P < 0.01) by CA. ANGPTL4 protein levels were increased 2-fold (P < 0.05) by WSD, but restored following oxfenicine. For CA-hearts WSD increased ANGPTL4 protein levels 3-fold (P < 0.01) with WSD + oxfenicine increasing ANGPTL4 protein 4-fold (P < 0.01). These data suggest that endothelial LPL levels in the heart are altered to maintain FA flux and may exploit ANGPTL4. PMID:22226882

  7. Retrobiosynthetic nuclear magnetic resonance analysis of amino acid biosynthesis and intermediary metabolism. Metabolic flux in developing maize kernels.

    PubMed

    Glawischnig, E; Gierl, A; Tomas, A; Bacher, A; Eisenreich, W

    2001-03-01

    Information on metabolic networks could provide the basis for the design of targets for metabolic engineering. To study metabolic flux in cereals, developing maize (Zea mays) kernels were grown in sterile culture on medium containing [U-(13)C(6)]glucose or [1,2-(13)C(2)]acetate. After growth, amino acids, lipids, and sitosterol were isolated from kernels as well as from the cobs, and their (13)C isotopomer compositions were determined by quantitative nuclear magnetic resonance spectroscopy. The highly specific labeling patterns were used to analyze the metabolic pathways leading to amino acids and the triterpene on a quantitative basis. The data show that serine is generated from phosphoglycerate, as well as from glycine. Lysine is formed entirely via the diaminopimelate pathway and sitosterol is synthesized entirely via the mevalonate route. The labeling data of amino acids and sitosterol were used to reconstruct the labeling patterns of key metabolic intermediates (e.g. acetyl-coenzyme A, pyruvate, phosphoenolpyruvate, erythrose 4-phosphate, and Rib 5-phosphate) that revealed quantitative information about carbon flux in the intermediary metabolism of developing maize kernels. Exogenous acetate served as an efficient precursor of sitosterol, as well as of amino acids of the aspartate and glutamate family; in comparison, metabolites formed in the plastidic compartments showed low acetate incorporation. PMID:11244098

  8. Influence of gas-particle partitioning on ammonia and nitric acid fluxes above a deciduous forest in the Midwestern USA

    NASA Astrophysics Data System (ADS)

    Hansen, K.; Sørensen, L. L.; Hornsby, K. E.; Boegh, E.; Pryor, S. C.

    2013-12-01

    Quantifying the atmosphere-biosphere exchange of reactive nitrogen gasses (including ammonia (NH3) and nitric acid (HNO3)) is crucial to assessing the impact of anthropogenic activities on natural and semi-natural ecosystems. However, measuring the deposition of reactive nitrogen is challenging due to bi-directionality of the flux, and the dynamics of the chemical gas/aerosol equilibrium of NH3 and HNO3 (or other atmospheric acids) with aerosol-phase ammonium (NH4+) and nitrate (NO3-). NH3 and HNO3 are both very reactive and typically exhibit higher deposition velocities than aerosol NH4+. Therefore, the phase partitioning between gas and aerosol phases can have a significant effect on local budgets and atmospheric transport distances (Nemitz et al., Atmos. Chem. Phys., 2004). In this study, fluxes of NH3, HNO3 and carbon dioxide (CO2) along with size-resolved N-aerosol concentrations are measured above the deciduous forest, Morgan Monroe State Forest (MMSF) in south-central Indiana (39°53'N, 86°25'W) during a field campaign. Two relaxed eddy accumulation (REA) systems are used to measure fluxes and concentrations of NH3 and HNO3 at 44 m. The NH3 REA system operates based on wet effluent diffusion denuders with detection by florescence and half-hourly flux measurements are calculated. HNO3 REA system is based on gas capture on sodium chloride (NaCl) coated denuders with subsequent analysis by ion-chromatography, and the resulting fluxes have a resolution of 3-4 hours. CO2 fluxes are measured by eddy covariance using a closed-path Licor LI-7500, while two MSP MOUDI-110 impactors are used to measure the 24-hourly average inorganic and 48 hourly averaged organic ion concentrations in 11 size bins, respectively, just above the canopy level (28 m). The results of this field campaign are used to quantify the fluxes of NH3, HNO3, CO2 to/from the forest during the transition towards senescence, and to investigate process-level controls (e.g. the role of phase

  9. Controls on suppression of methane flux from a peat bog subjected to simulated acid rain sulfate deposition

    NASA Astrophysics Data System (ADS)

    Gauci, Vincent; Dise, Nancy; Fowler, David

    2002-01-01

    The effect of acid rain SO42- deposition on peatland CH4 emissions was examined by manipulating SO42- inputs to a pristine raised peat bog in northern Scotland. Weekly pulses of dissolved Na2SO4 were applied to the bog over two years in doses of 25, 50, and 100 kg S ha-1 yr-1, reflecting the range of pollutant S deposition loads experienced in acid rain-impacted regions of the world. CH4 fluxes were measured at regular intervals using a static chamber/gas chromatographic flame ionization detector method. Total emissions of CH4 were reduced by between 21 and 42% relative to controls, although no significant differences were observed between treatments. Estimated total annual fluxes during the second year of the experiment were 16.6 g m-2 from the controls and (in order of increasing SO42- dose size) 10.7, 13.2, and 9.8 g m-2 from the three SO42- treatments, respectively. The relative extent of CH4 flux suppression varied with changes in both peat temperature and peat water table with the largest suppression during cool periods and episodes of falling water table. Our findings suggest that low doses of SO42- at deposition rates commonly experienced in areas impacted by acid rain, may significantly affect CH4 emissions from wetlands in affected areas. We propose that SO42- from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates. We further propose that this microbially mediated interaction may have a significant current and future effect on the contribution of northern peatlands to the global methane budget.

  10. Curcumin protects hearts from FFA-induced injury by activating Nrf2 and inactivating NF-κB both in vitro and in vivo.

    PubMed

    Zeng, Chunlai; Zhong, Peng; Zhao, Yunjie; Kanchana, Karvannan; Zhang, Yali; Khan, Zia A; Chakrabarti, Subrata; Wu, Lianpin; Wang, Jingying; Liang, Guang

    2015-02-01

    Obesity and increased free fatty acid (FFA) level are tightly linked, leading to the development of cardiovascular disorders. Curcumin is a natural product from Curcuma longa with multiple bioactivities and is known to have cardioprotective effects in several cellular and animal models. The current study was designed to evaluate the cardioprotective effects of curcumin and demonstrate the underlying mechanism in FFA-induced cardiac injury. Using cell culture studies and high fat in vivo model, we explored the mechanistic basis of anti-inflammatory and antioxidant activities of curcumin. We observed that palmitate (PA) treatment in cardiac derived H9C2 cells induced a marked increase in reactive oxygen species, inflammation, apoptosis and hypertrophy. All of these changes were effectively suppressed by curcumin treatment. In addition, oral administration of curcumin at 50mg/kg completely suppressed high fat diet-induced oxidative stress, inflammation, apoptosis, fibrosis, hypertrophy and tissue remodeling in mice. The beneficial actions of curcumin are closely associated with its ability to increase Nrf2 expression and inhibit NF-κB activation. Thus, both in vitro and in vivo studies showed a promising role of curcumin as a cardioprotective agent against palmitate and high fat diet mediated cardiac dysfunction. We indicated the regulatory roles of Nrf2 and NF-κB in obesity-induced heart injury, and suggested that they may be important therapeutic targets in the treatment of obesity-related disorders. PMID:25444713

  11. Heparin, free fatty acids and an increased metabolic demand for oxygen.

    PubMed

    Jung, R T; Shetty, P S; James, W P

    1980-05-01

    Obese and lean subjects were given heparin with or without Intralipid in order to assess the effect of heparin on plasma concentration of free fatty acids (FFA) and oxidative metabolism. The FFA response depended on the triglyceride concentration and was associated with a prompt rise in oxygen consumption. Plasma catecholamines did not alter after heparin and the increase in oxygen uptake was proportional to the rise in FFA. The use of heparin, therefore, has metabolic disadvantages which may outweigh the potential benefits, for example in the management of myocardial infarction where heparin may increase the metabolic demand on the heart by increasing FFA levels. PMID:7443592

  12. Heparin, free fatty acids and an increased metabolic demand for oxygen.

    PubMed Central

    Jung, R. T.; Shetty, P. S.; James, W. P.

    1980-01-01

    Obese and lean subjects were given heparin with or without Intralipid in order to assess the effect of heparin on plasma concentration of free fatty acids (FFA) and oxidative metabolism. The FFA response depended on the triglyceride concentration and was associated with a prompt rise in oxygen consumption. Plasma catecholamines did not alter after heparin and the increase in oxygen uptake was proportional to the rise in FFA. The use of heparin, therefore, has metabolic disadvantages which may outweigh the potential benefits, for example in the management of myocardial infarction where heparin may increase the metabolic demand on the heart by increasing FFA levels. PMID:7443592

  13. Investigating the stomatal, cuticular and soil ammonia fluxes over a growing tritical crop under high acidic loads

    NASA Astrophysics Data System (ADS)

    Loubet, B.; Decuq, C.; Personne, E.; Massad, R. S.; Flechard, C.; Fanucci, O.; Mascher, N.; Gueudet, J.-C.; Masson, S.; Durand, B.; Génermont, S.; Fauvel, Y.; Cellier, P.

    2011-10-01

    Ammonia concentration and fluxes were measured above a growing triticale field for two months during May and June 2010 at the NitroEurope crop site in Grignon (Fr-Gri) near Paris, France. The measurement campaign started 15 days following a 40 kg N ha-1 application of an ammonium nitrate solution. A new mini-WEDD (Wet Effluent Denuder) flow injection analyser with three channels (ROSAA, RObust and Sensitive Ammonia Analyser) was used to measure NH3 fluxes using the aerodynamic gradient method. The measured ammonia concentrations varied from 0.01 to 39 μg NH3 m-3 and were largely influenced by advection from the nearby farm. The ammonia fluxes ranged from -560 to 220 ng NH3 m-2 s-1 and averaged -29 ng NH3 m-2 s-1. During some periods the large deposition fluxes could only be explained by a very small surface resistance, which may be due to the high concentrations in certain acid gases (HNO3 and SO2) observed in this suburban area. Ammonia emissions were also measured occasionally. The canopy compensation point Cc was around 1.5 μg NH3 m-3 on average. The canopy emission potential Γc (Cc normalised for the temperature response of the Henry equilibrium) decreased over the course of the measurement campaign from Γc = 2200 to Γc = 450, the latter value being close to the median stomatal emission potential (Γs) for managed ecosystems reported in the literature. The temporal dynamics of the measured NH3 flux compared well with the Surfatm- NH3 model using fitted parameters. The subjectivity of the model fitting is discussed based on a sensitivity analysis.

  14. Investigating the stomatal, cuticular and soil ammonia fluxes over a growing tritical crop under high acidic loads

    NASA Astrophysics Data System (ADS)

    Loubet, B.; Decuq, C.; Personne, E.; Massad, R. S.; Flechard, C.; Fanucci, O.; Mascher, N.; Gueudet, J.-C.; Masson, S.; Durand, B.; Genermont, S.; Fauvel, Y.; Cellier, P.

    2012-04-01

    Ammonia concentration and fluxes were measured above a growing triticale field for two months during May and June 2010 at the NitroEurope crop site in Grignon (Fr-Gri) near Paris, France. The measurement campaign started 15 days following a 40 kg N ha-1 application of an ammonium nitrate solution. A new mini-wedd (Wet Effluent Denuder) flow injection analyser with three channels (ROSAA, RObust and Sensitive Ammonia Analyser) was used to measure NH3 fluxes using the aerodynamic gradient method. The measured ammonia concentrations varied from 0.01 to 39 μg NH3 m-3 and were largely influenced by advection from the nearby farm. The ammonia fluxes ranged from -560 to 220 ng NH3 m-2 s-1 and averaged -29 ng NH3 m-2 s-1. During some periods the large deposition fluxes could only be explained by a very small surface resistance, which may be partly due to the high concentrations of certain acid gases (HNO3 and SO2) observed in this suburban area. Ammonia emissions were also observed. The canopy compensation point Cc was around 1.5 μg NH3 m-3 on average. The canopy emission potential Γc (Cc normalised for the temperature response of the Henry equilibrium) decreased over the course of the measurement campaign from Γc = 2200 to Γc = 450, the latter value being close to the median stomatal emission potential (Γs) and lower than the median ground emission potential (Γg) for managed ecosystems reported in the literature. The temporal dynamics of the measured NH3 flux compared well with the Surfatm-NH3 model using fitted parameters. The subjectivity of the model fitting is discussed based on a sensitivity analysis.

  15. Carbon Flux Trapping: Highly Efficient Production of Polymer-Grade d-Lactic Acid with a Thermophilic d-Lactate Dehydrogenase.

    PubMed

    Li, Chao; Tao, Fei; Xu, Ping

    2016-08-17

    High production of polymer-grade d-lactic acid is urgently required, particularly for the synthesis of polylactic acid. High-temperature fermentation has multiple advantages, such as lower equipment requirement and energy consumption, which are essential for lowering operating costs. We identified and introduced a unique d-lactate dehydrogenase into a thermotolerant butane-2,3-diol-producing strain. Carbon flux "trapping" was achieved by a "trapping point" created by combination of the introduced enzyme and the host efflux pump, which afforded irreversible transport of d-lactic acid. The overall carbon flux of the engineered strain was significantly enhanced and was redistributed predominantly to d-lactic acid. Under optimized conditions at 50 °C, d-lactic acid reached the highest titer (226.6 g L(-1) ) reported to date. This discovery allows us to extend the carbon flux trapping strategy to engineering complex metabolic networks. PMID:27237045

  16. Net flux of amino acids across splanchnic tissues of ewes during abomasal protein and glucose infusion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction Studies in sheep (MacRae et al., 1997) and in pigs (Stoll et al., 1998) indicated approximately one-third of the amino acids absorbed by the enterocyte are metabolized within the enterocyte and are never released into the blood. Of those amino acids that are metabolized, 60% are appar...

  17. Engineering oilseeds for sustainable production of industrial and nutritional feedstocks: solving bottlenecks in fatty acid flux

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oils provide a platform for the production of high-value fatty acids that can replace non-sustainable petroleum and oceanic sources of specialty chemicals and aquaculture feed. Recent efforts to engineer seeds of crop and model species to produce new types of fatty acid structures for thes...

  18. Short-chain fatty acid sensing in rat duodenum

    PubMed Central

    Akiba, Yasutada; Inoue, Takuya; Kaji, Izumi; Higashiyama, Masaaki; Narimatsu, Kazuyuki; Iwamoto, Ken-ichi; Watanabe, Masahiko; Guth, Paul H; Engel, Eli; Kuwahara, Atsukazu; Kaunitz, Jonathan D

    2015-01-01

    Intraduodenal fatty acids (FA) and bacterial overgrowth, which generate short-chain FAs (SCFAs), have been implicated in the generation of functional dyspepsia symptoms. We studied the mechanisms by which luminal SCFA perfusion affects duodenal HCO3− secretion (DBS), a measure of mucosal neurohumoral activation. Free fatty acid receptor (FFAR) 1 (FFA1), which binds long-chain FA (LCFA), and SCFA receptors FFA2 and FFA3 were immunolocalised to duodenal enteroendocrine cells. FFA3 colocalised with glucagon-like peptide (GLP)-1, whereas FFA2 colocalised with 5-HT. Luminal perfusion of the SCFA acetate or propionate increased DBS, enhanced by dipeptidyl peptidase-IV (DPPIV) inhibition, at the same time as increasing GLP-2 portal blood concentrations. Acetate-induced DBS was partially inhibited by monocarboxylate/HCO3− exchanger inhibition without affecting GLP-2 release, implicating acetate absorption in the partial mediation of DBS. A selective FFA2 agonist dose-dependently increased DBS, unaffected by DPPIV inhibition or by cholecystokinin or 5-HT3 receptor antagonists, but was inhibited by atropine and a 5-HT4 antagonist. By contrast, a selective FFA1 agonist increased DBS accompanied by GLP-2 release, enhanced by DPPIV inhibition and inhibited by a GLP-2 receptor antagonist. Activation of FFA1 by LCFA and presumably FFA3 by SCFA increased DBS via GLP-2 release, whereas FFA2 activation stimulated DBS via muscarinic and 5-HT4 receptor activation. SCFA/HCO3− exchange also appears to be present in the duodenum. The presence of duodenal fatty acid sensing receptors that signal hormone release and possibly signal neural activation may be implicated in the pathogenesis of functional dyspepsia. PMID:25433076

  19. Catalytic synthesis of biodiesel from high free fatty acid-containing feedstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recyclable and reusable heterogeneous diarylammonium catalysts are highly effective in catalyzing the esterification of the free fatty acid (FFA) present in greases to methyl esters to reduce the FFA content from 12-40 wt% to 0.5 – 1 wt%. The resulting ester-glyceride mixture (pretreated grease) co...

  20. Impact of ENSO variability on the flux and composition of sinking POM in the western equatorial Pacific Ocean: Amino acids and hexosamines

    NASA Astrophysics Data System (ADS)

    Gupta, Lallan Prasad; Kawahata, Hodaka

    Sediment trap moorings deployed along the equator at three distinct oceanographic zones within the western Pacific Ocean during 1991-93, 1994-95, and 1999 provided data on total mass and amino acid fluxes and composition of particulate organic matter (POM) sinking in this part of the Pacific. An intercomparison of annual averages of various parameters revealed discrete patterns in flux and composition of POM under the El Niño (1991-93, 1994-95) and La Niña (1999) conditions that prevailed over the equatorial Pacific during the sampling periods. In the hemipelagic zone of the far western equatorial Pacific, where terrestrial deposition of particles larger than 5 μm accounts for >25% of the total sediment, average total mass and amino acid fluxes were relatively higher during El Niño than during La Niña. However, at the oligotrophic warm pool and upwelling sites, total mass and amino acid fluxes were higher during La Niña. Influence of ENSO-related changes in the sinking particle flux was much clearer in the hemipelagic zone compared to that in the warm pool. Average values of biogeochemical parameters such as glucosamine/galactosamine and amino acids/hexosamines, and bulk parameters like amino acid carbon and nitrogen contents relative to organic carbon and total nitrogen (THAA-C% and THAA-N%, respectively), and organic carbon normalised amino acid concentrations indicated that sinking POM was more labile during La Niña at all the sites. The ratios Aspartic acid/ β-alanine, Glutamic acid/ γ-aminobutyric acid, and relative concentration of non-protein amino acids ( β-alanine+ γ-aminobutyric acid) suggested that POM degradation was more intense during La Niña than during El Niño conditions at all sites. >

  1. A Novel RSSI Prediction Using Imperialist Competition Algorithm (ICA), Radial Basis Function (RBF) and Firefly Algorithm (FFA) in Wireless Networks.

    PubMed

    Goudarzi, Shidrokh; Haslina Hassan, Wan; Abdalla Hashim, Aisha-Hassan; Soleymani, Seyed Ahmad; Anisi, Mohammad Hossein; Zakaria, Omar M

    2016-01-01

    This study aims to design a vertical handover prediction method to minimize unnecessary handovers for a mobile node (MN) during the vertical handover process. This relies on a novel method for the prediction of a received signal strength indicator (RSSI) referred to as IRBF-FFA, which is designed by utilizing the imperialist competition algorithm (ICA) to train the radial basis function (RBF), and by hybridizing with the firefly algorithm (FFA) to predict the optimal solution. The prediction accuracy of the proposed IRBF-FFA model was validated by comparing it to support vector machines (SVMs) and multilayer perceptron (MLP) models. In order to assess the model's performance, we measured the coefficient of determination (R2), correlation coefficient (r), root mean square error (RMSE) and mean absolute percentage error (MAPE). The achieved results indicate that the IRBF-FFA model provides more precise predictions compared to different ANNs, namely, support vector machines (SVMs) and multilayer perceptron (MLP). The performance of the proposed model is analyzed through simulated and real-time RSSI measurements. The results also suggest that the IRBF-FFA model can be applied as an efficient technique for the accurate prediction of vertical handover. PMID:27438600

  2. A Novel RSSI Prediction Using Imperialist Competition Algorithm (ICA), Radial Basis Function (RBF) and Firefly Algorithm (FFA) in Wireless Networks

    PubMed Central

    Goudarzi, Shidrokh; Haslina Hassan, Wan; Abdalla Hashim, Aisha-Hassan; Soleymani, Seyed Ahmad; Anisi, Mohammad Hossein; Zakaria, Omar M.

    2016-01-01

    This study aims to design a vertical handover prediction method to minimize unnecessary handovers for a mobile node (MN) during the vertical handover process. This relies on a novel method for the prediction of a received signal strength indicator (RSSI) referred to as IRBF-FFA, which is designed by utilizing the imperialist competition algorithm (ICA) to train the radial basis function (RBF), and by hybridizing with the firefly algorithm (FFA) to predict the optimal solution. The prediction accuracy of the proposed IRBF–FFA model was validated by comparing it to support vector machines (SVMs) and multilayer perceptron (MLP) models. In order to assess the model’s performance, we measured the coefficient of determination (R2), correlation coefficient (r), root mean square error (RMSE) and mean absolute percentage error (MAPE). The achieved results indicate that the IRBF–FFA model provides more precise predictions compared to different ANNs, namely, support vector machines (SVMs) and multilayer perceptron (MLP). The performance of the proposed model is analyzed through simulated and real-time RSSI measurements. The results also suggest that the IRBF–FFA model can be applied as an efficient technique for the accurate prediction of vertical handover. PMID:27438600

  3. Single-step enantioselective amino acid flux analysis by capillary electrophoresis using on-line sample preconcentration with chemical derivatization.

    PubMed

    Ptolemy, Adam S; Tran, Lara; Britz-McKibbin, Philip

    2006-07-15

    Capillary electrophoresis (CE) represents a versatile platform for integrating sample pretreatment with chemical analysis because of its ability to tune analyte electromigration and band dispersion properties in discontinuous electrolyte systems. In this article, a single-step method that combines on-line sample preconcentration with in-capillary chemical derivatization is developed for rapid, sensitive, and enantioselective analysis of micromolar levels of amino acids that lack intrinsic chromophores by CE with UV detection. Time-resolved electrophoretic studies revealed two distinct stages of amino acid band narrowing within the original long sample injection plug occurring both prior to and after in-capillary labeling via zone passing by ortho-phthalaldehyde/N-acetyl l-cysteine (OPA/NAC). This technique enabled direct analysis of d-amino acids in a 95% enantiomeric excess mixture with sub-micromolar detection limits and minimal sample handling, where the capillary functions as a preconcentrator, microreactor, and chiral selector. On-line sample preconcentration with chemical derivatization CE (SPCD-CE) was applied to study the enantioselective amino acid flux in Escherichia coli bacteria cultures, which demonstrated a unique l-Ala efflux into the extracellular medium. New strategies for high-throughput analyses of low-abundance metabolites are important for understanding fundamental physiological processes in bacteria required for screening the efficacy of new classes of antibiotics as well as altered metabolism in genetically modified mutant strains. PMID:16753129

  4. Stage-Specific Fatty Acid Fluxes Play a Regulatory Role in Glycerolipid Metabolism during Seed Development in Jatropha curcas L.

    PubMed

    Chaitanya, Bharatula Sri Krishna; Kumar, Sumit; Kaki, Shiva Shanker; Balakrishna, Marrapu; Karuna, Mallampalli Sri Lakshmi; Prasad, Rachapudi Badari Narayana; Sastry, Pidaparty Seshadri; Reddy, Attipalli Ramachandra

    2015-12-23

    The present study describes the changes in lipid profile as well as fatty acid fluxes during seed development in Jatropha curcas L. Endosperm from 34, 37, and 40 days after anthesis (DAA), incubated with [(14)C]acetate, showed significant synthesis of phosphatidylcholine (PC) at seed maturation. The fatty acid methyl ester profile showed PC from 34 DAA was rich in palmitic acid (16:0), whereas PC from 37 and 40 DAA was rich in oleic acid (18:1n-9). Molecular species analysis of diacylglycerol (DAG) indicated DAG (16:0/18:2n-6) was in abundance at 34 DAA, whereas DAG (18:1n-9/18:2n-6) was significantly high at 40 DAA. Triacylglycerol (TAG) analysis revealed TAG (16:0/18:2n-6/16:0) was abundant at 34 DAA, whereas TAG (18:1n-9/18:2n-6/18:1n-9) formed the majority at 40 DAA. Expression of two types of diacylglycerol acyltransferases varied with seed maturation. These data demonstrate stage-specific distinct pools of PC and DAG synthesis during storage TAG accumulation in Jatropha seed. PMID:26628196

  5. Monolignol Pathway 4-Coumaric Acid:Coenzyme A Ligases in Populus. trichocarpa: Novel Specificity, Metabolic Regulation, and Simulation of Coenzyme A Ligation Fluxes1[W

    PubMed Central

    Chen, Hsi-Chuan; Song, Jina; Williams, Cranos M.; Shuford, Christopher M.; Liu, Jie; Wang, Jack P.; Li, Quanzi; Shi, Rui; Gokce, Emine; Ducoste, Joel; Muddiman, David C.; Sederoff, Ronald R.; Chiang, Vincent L.

    2013-01-01

    4-Coumaric acid:coenzyme A ligase (4CL) is involved in monolignol biosynthesis for lignification in plant cell walls. It ligates coenzyme A (CoA) with hydroxycinnamic acids, such as 4-coumaric and caffeic acids, into hydroxycinnamoyl-CoA thioesters. The ligation ensures the activated state of the acid for reduction into monolignols. In Populus spp., it has long been thought that one monolignol-specific 4CL is involved. Here, we present evidence of two monolignol 4CLs, Ptr4CL3 and Ptr4CL5, in Populus trichocarpa. Ptr4CL3 is the ortholog of the monolignol 4CL reported for many other species. Ptr4CL5 is novel. The two Ptr4CLs exhibited distinct Michaelis-Menten kinetic properties. Inhibition kinetics demonstrated that hydroxycinnamic acid substrates are also inhibitors of 4CL and suggested that Ptr4CL5 is an allosteric enzyme. Experimentally validated flux simulation, incorporating reaction/inhibition kinetics, suggested two CoA ligation paths in vivo: one through 4-coumaric acid and the other through caffeic acid. We previously showed that a membrane protein complex mediated the 3-hydroxylation of 4-coumaric acid to caffeic acid. The demonstration here of two ligation paths requiring these acids supports this 3-hydroxylation function. Ptr4CL3 regulates both CoA ligation paths with similar efficiencies, whereas Ptr4CL5 regulates primarily the caffeic acid path. Both paths can be inhibited by caffeic acid. The Ptr4CL5-catalyzed caffeic acid metabolism, therefore, may also act to mitigate the inhibition by caffeic acid to maintain a proper ligation flux. A high level of caffeic acid was detected in stem-differentiating xylem of P. trichocarpa. Our results suggest that Ptr4CL5 and caffeic acid coordinately modulate the CoA ligation flux for monolignol biosynthesis. PMID:23344904

  6. Free Fatty Acid Uptake in Humans With CD36 Deficiency

    PubMed Central

    Hames, Kazanna C.; Vella, Adrian; Kemp, Bradley J.

    2014-01-01

    Animal models have demonstrated that CD36 facilitates cell membrane free fatty acid (FFA) transport, but its role in human metabolism is not well understood. We measured heart, liver, adipose (three depots), and muscle (truncal postural and thigh locomotive) FFA uptake using [11C]palmitate positron emission tomography (PET) scans in a family of five carrying the Pro90Ser CD36 mutation (2 homozygotes had no CD36) and matched control volunteers. PET scans were done under conditions of suppressed and slightly increased palmitate concentrations. During suppressed palmitate conditions, muscle and adipose palmitate uptake were markedly reduced in homozygotes but not heterozygotes for the Pro90Ser CD36 mutation, whereas when palmitate concentration was slightly increased, uptake in muscle and adipose did not differ between control subjects and homozygous family members. Hepatic FFA uptake was similar in all participants regardless of palmitate concentrations, whereas myocardial FFA uptake was diminished in the Pro90Ser homozygotes during both suppressed and increased palmitate conditions. We conclude that CD36 1) facilitates FFA transport into muscle and adipose tissue in humans when extracellular concentrations are reduced but not when they are modestly elevated, 2) is not rate limiting for hepatic FFA uptake, and 3) is needed for normal cardiac FFA uptake over a range of FFA concentrations from low to slightly elevated. PMID:24917573

  7. Effects of Alterations of Plasma Free Fatty Acid Levels on Pancreatic Glucagon Secretion in Man

    PubMed Central

    Gerich, John E.; Langlois, Maurice; Schneider, Victor; Karam, John H.; Noacco, Claudio

    1974-01-01

    The present investigation was undertaken to ascertain whether alterations in plasma free fatty acids (FFA) affect pancreatic glucagon secretion in man since FFA have been reported to influence pancreatic alpha cell function in other species. Elevation of plasma FFA from a mean (±SE) basal level of 0.478±0.036 mM to 0.712±0.055 mM after heparin administration caused plasma glucagon levels to fall approximately 50%, from a basal value of 122±15 pg/ml to 59±14 pg/ml (P < 0.001). Lowering of plasma FFA from a basal level of 0.520±0.046 mM to 0.252±0.041 mM after nicotinic acid administration raised plasma glucagon from a basal level of 113±18 pg/ml to 168±12 pg/ml (P < 0.005). Infusion of glucose elevated plasma glucose levels to the same degree that heparin raised plasma FFA levels. This resulted in suppression of plasma glucagon despite the fact that plasma FFA levels also were suppressed. Glucagon responses to arginine were diminished after elevation of plasma FFA (P < 0.01) and during infusion of glucose (P < 0.01). Diminution of plasma FFA by nicotinic acid did not augment glucagon responses to arginine. These results thus demonstrate that rather small alterations in plasma FFA within the physiologic range have a significant effect on glucagon secretion in man. Although the effects of glucose appear to predominate over those of FFA, alterations in plasma FFA may nevertheless exert an important physiologic influence over human pancreatic alpha cell function, especially in the postabsorptive state. PMID:4825225

  8. Ileal mucosal absorption of bile acid in man: validation of a miniature flux chamber technique.

    PubMed Central

    Hosie, K B; Davie, R J; Panagamuwa, B; Grobler, S; Keighley, M R; Birch, N J

    1992-01-01

    A method that allows the quantitative assessment of ileal mucosal cell uptake and transport of bile acids in mucosal biopsy specimens has been validated. Viability of the tissue was confirmed by maintenance of normal cell morphology, wet weight, extracellular space, porosity to polyethylene glycol-900, lactate dehydrogenase release, and transmucosal potential difference. Using 14C-taurocholic acid, absorption was shown to be directional, capable of working against a concentration gradient, reduced by metabolic inhibitors, and sodium dependent. The system showed saturation kinetics with an estimated Km of 10 mumol/l. At a standard substrate concentration of 10 mumol/l ileal mucosal bile acid absorption was compared in patients with colorectal cancer (n = 6), ulcerative colitis (n = 10), and slow transit constipation (n = 8). There was no significant difference in tissue uptake or transport between the three groups. Images Figure 2 PMID:1582593

  9. Long-term suppression of wetland methane flux following a pulse of simulated acid rain

    NASA Astrophysics Data System (ADS)

    Gauci, Vincent; Dise, Nancy; Blake, Stephen

    2005-06-01

    Wetlands are a potent source of the radiatively important gas methane (CH4). Recent findings have demonstrated that sulfate (SO42-) deposition via acid rain suppresses CH4 emissions by stimulating competitive exclusion of methanogens by sulfate-reducing microbial populations. Here we report data from a field experiment showing that a finite pulse of simulated acid rain SO42- deposition, as would be expected from a large Icelandic volcanic eruption, continues to suppress CH4 emissions from wetlands long after the pollution event has ceased. Our analysis of the stoichiometries suggests that 5 years is a minimum CH4 emission recovery period, with 10 years being a reasonable upper limit. Our findings highlight the long-term impact of acid rain on biospheric output of CH4 which, for discrete polluting events such as volcanic eruptions, outlives the relatively short-term SO42- aerosol radiative cooling effect.

  10. Plasma free fatty acid metabolism during storage of platelet concentrates for transfusion.

    PubMed

    Cesar, J; DiMinno, G; Alam, I; Silver, M; Murphy, S

    1987-01-01

    New containers allow storage of platelet concentrates (PC) at 22 degrees C for up to 7 days, during which glycolytic and oxidative metabolism is vigorous. Recent evidence suggests that 85 percent of adenosine triphosphate regeneration is based on oxidative metabolism and that substrates other than glucose may be used. Because platelets can oxidize free fatty acids (FFA) as a possible source of energy during storage, the authors studied their availability, distribution, and turnover. Plasma FFA concentration was unchanged after 1 day of PC storage but significantly increased on Days 3, 5, and 7. Platelet-free plasma (PFP) stored under the same conditions as PC demonstrated a progressive increase in FFA, suggesting that some of the FFA accumulating in PC were derived from plasma rather than platelets. Indeed, during PC storage, plasma triglycerides decreased significantly, suggesting that they are a possible source of the increased levels of FFA found on Day 3 and thereafter. Thus, PC have a plasma FFA pool available continuously for oxidation during storage. Studies with radiolabeled palmitate suggested that FFA oxidation by platelets occurs during storage. The current findings show that plasma FFA could be a significant substrate for oxidative metabolism during storage of PC and that the oxidized FFA are replenished at least in part from plasma. These results may allow platelet storage to be improved, particularly in synthetic media. PMID:3629676

  11. Accumulating Evidence Supports a Taste Component for Free Fatty Acids in Humans

    PubMed Central

    Mattes, Richard D.

    2011-01-01

    The requisite criteria for what constitutes a taste primary have not been established. Recent advances in understanding of the mechanisms and functions of taste have prompted suggestions for an expanded list of unique taste sensations, including fat, or more specifically, free fatty acids (FFA). A set of criteria are proposed here and the data related to FFA are reviewed on each point. It is concluded that the data are moderate to strong that there are: A) adaptive advantages to FFA detection in the oral cavity; B) adequate concentrations of FFA to serve as taste stimuli; C) multiple complimentary putative FFA receptors on taste cells; D) signals generated by FFA that are conveyed by gustatory nerves; E) sensations generated by FFA that can be detected and scaled by psychophysical methods in humans when non-gustatory cues are masked; and F) physiological responses to oral fat/FFA exposure. On no point is there strong evidence challenging these observations. The reviewed findings are suggestive, albeit not definitive, that there is a taste component for FFA. PMID:21557960

  12. Distribution of carbon flux within fatty acid utilization during myocardial ischemia and reperfusion

    SciTech Connect

    Nellis, S.H.; Liedtke, A.J.; Renstrom, B. )

    1991-09-01

    Twenty-nine intact, working pig hearts were extracorporeally perfused and divided into two study groups (16 Aerobic and 13 Ischemic/Reflow hearts). Step function, equilibrium labeling with (14C)palmitate was used to develop uptake and washout curves of radioactive fatty acid products contained in coronary effluent during either aerobic perfusion or reperfusion after ischemia (60% reduction in left anterior descending coronary flow for 30 minutes). Left anterior descending control flows were slightly overperfused in Aerobic hearts (18% higher than in Ischemic/Reflow hearts); otherwise, circumflex and right coronary flows, left ventricular pressure, and serum fatty acids and blood sugar levels were comparable between groups. As expected in Ischemic/Reflow hearts, recovery of regional systolic shortening and myocardial oxygen consumption in reperfusion was only modestly impaired (-20% and -19%, respectively, not significant and p less than 0.011 compared with preischemic values, not significant from Aerobic hearts). The only significant metabolized product to be released from labeled fatty acid utilization in either group was 14CO2. A smaller fatty acid pool also was measured and accounted for by that contained in the coronary intravascular volume. The authors could determine no significant back diffusion of fatty acids from myocardium in either perfusion condition. Uptake time constants of the early phase of 14CO2 production also were virtually identical in both groups (19.9 {plus minus} 3.2 versus 16.7 {plus minus} 3.2 minutes in Aerobic and Ischemic/Reflow hearts, respectively) and strongly correlated with hemodynamics as described by heart rate. In washout studies, tissue radioactivity in the aqueous soluble and fatty acid pools declined in both study groups, and counts in complex lipids and cholesterol/cholesteryl esters remained steady, whereas those in triacylglycerols varied.

  13. Splanchnic free fatty acid kinetics.

    PubMed

    Jensen, Michael D; Cardin, Sylvain; Edgerton, Dale; Cherrington, Alan

    2003-06-01

    These studies were conducted to assess the relationship between visceral adipose tissue free fatty acid (FFA) release and splanchnic FFA release. Steady-state splanchnic bed palmitate ([9,10-(3)H]palmitate) kinetics were determined from 14 sampling intervals from eight dogs with chronic indwelling arterial, portal vein, and hepatic vein catheters. We tested a model designed to predict the proportion of FFAs delivered to the liver from visceral fat by use of hepatic vein data. The model predicted that 15 +/- 2% of hepatic palmitate delivery originated from visceral lipolysis, which was greater (P = 0.004) than the 11 +/- 2% actually observed. There was a good relationship (r(2) = 0.63) between the predicted and observed hepatic palmitate delivery values, but the model overestimated visceral FFA release more at lower than at higher palmitate concentrations. The discrepancy could be due to differential uptake of FFAs arriving from the arterial vs. the portal vein or to release of FFAs in the hepatic circulatory bed. Splanchnic FFA release measured using hepatic vein samples was strongly related to visceral adipose tissue FFA release into the portal vein. This finding suggests that splanchnic FFA release is a good indicator of visceral adipose tissue lipolysis. PMID:12736157

  14. Synthesis and regulation of chlorogenic acid in potato: Rerouting phenylpropanoid flux in HQT silenced lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chlorogenic acid (CGA) is the major phenolic sink in potato tubers and can constitute over 90% of total phenylpropanoids. The regulation of CGA biosynthesis in potato and the role of the CGA biosynthetic gene hydroxycinnamoyl-CoA:quinate hydroxycinnamoyl transferase (HQT) was characterized. A sucros...

  15. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer.

    PubMed

    Cánovas, C R; Macías, F; Pérez-López, R

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  16. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    NASA Astrophysics Data System (ADS)

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  17. The Exocyst Complex Regulates Free Fatty Acid Uptake by Adipocytes

    PubMed Central

    Inoue, Mayumi; Akama, Takeshi; Jiang, Yibin; Chun, Tae-Hwa

    2015-01-01

    The exocyst is an octameric molecular complex that drives vesicle trafficking in adipocytes, a rate-limiting step in insulin-dependent glucose uptake. This study assessed the role of the exocyst complex in regulating free fatty acid (FFA) uptake by adipocytes. Upon differentiating into adipocytes, 3T3-L1 cells acquire the ability to incorporate extracellular FFAs in an insulin-dependent manner. A kinetic assay using fluoresceinated FFA (C12 dodecanoic acid) uptake allows the real-time monitoring of FFA internalization by adipocytes. The insulin-dependent uptake of C12 dodecanoic acid by 3T3-L1 adipocytes is mediated by Akt and phosphatidylinositol 3 (PI3)-kinase. Gene silencing of the exocyst components Exo70 and Sec8 significantly reduced insulin-dependent FFA uptake by adipocytes. Consistent with the roles played by Exo70 and Sec8 in FFA uptake, mCherry-tagged Exo70 and HA-tagged Sec8 partially colocalize with lipid droplets within adipocytes, suggesting their active roles in the development of lipid droplets. Tubulin polymerization was also found to regulate FFA uptake in collaboration with the exocyst complex. This study demonstrates a novel role played by the exocyst complex in the regulation of FFA uptake by adipocytes. PMID:25768116

  18. Leaf fluxes of NO and NO 2 in four herbaceous plant species: The role of ascorbic acid

    NASA Astrophysics Data System (ADS)

    Teklemariam, Thomas A.; Sparks, Jed P.

    Nitrogen oxides (NO x=NO+NO 2) are a common group of nitrogen-containing trace gases that interact significantly with plant canopies and play a critical role in atmospheric chemistry including the formation of ozone, smog and nitric acid. The controls over leaf-atmosphere exchange of NO x (NO x=NO+NO 2) have been characterized for a few plant species and important drivers have been identified including stomatal conductance, the partial pressure gradient from the interior to the exterior of the leaf, and, most recently the level of ultraviolet radiation. However, our ability to predict leaf fluxes has been hampered by a dearth of information describing the reactions occurring between NO x and internal constituents of the leaf (often referred to as the mesophyllic resistance). In this study, we investigated NO x uptake in four important agricultural plant species and specifically tested the hypothesis that ascorbic acid within the leaf was a significant control over mesophyllic resistance. Measurements were made using a dynamic leaf chamber at ambient mixing ratios typical of urban atmospheres. Measured NO and NO 2 leaf fluxes were lower than the potential flux calculated assuming stomatal conductance as the sole limitation (i.e., no mesophyllic resistance). The ratios of leaf intercellular to ambient concentrations (C/C) for NO across partial pressures and plant species was usually >0.99 and the leaf uptake rates of NO were negligible within the ranges examined. In contrast, leaf uptake for NO 2 was much greater and C/C were often as low as 0.75. For both gases, C/C ratios>1 were observed at low ambient mixing ratios indicating emission from leaves. Across plant species, plants with higher leaf nitrogen contents showed higher NO 2 emission rates and plants with higher leaf ascorbate concentrations had higher leaf NO 2 uptake rates. These results suggest that in addition to the known effects of stomatal conductance and incident UV radiation, leaf nitrogen content and

  19. The Key to Acetate: Metabolic Fluxes of Acetic Acid Bacteria under Cocoa Pulp Fermentation-Simulating Conditions

    PubMed Central

    Adler, Philipp; Frey, Lasse Jannis; Berger, Antje; Bolten, Christoph Josef; Hansen, Carl Erik

    2014-01-01

    Acetic acid bacteria (AAB) play an important role during cocoa fermentation, as their main product, acetate, is a major driver for the development of the desired cocoa flavors. Here, we investigated the specialized metabolism of these bacteria under cocoa pulp fermentation-simulating conditions. A carefully designed combination of parallel 13C isotope labeling experiments allowed the elucidation of intracellular fluxes in the complex environment of cocoa pulp, when lactate and ethanol were included as primary substrates among undefined ingredients. We demonstrate that AAB exhibit a functionally separated metabolism during coconsumption of two-carbon and three-carbon substrates. Acetate is almost exclusively derived from ethanol, while lactate serves for the formation of acetoin and biomass building blocks. Although this is suboptimal for cellular energetics, this allows maximized growth and conversion rates. The functional separation results from a lack of phosphoenolpyruvate carboxykinase and malic enzymes, typically present in bacteria to interconnect metabolism. In fact, gluconeogenesis is driven by pyruvate phosphate dikinase. Consequently, a balanced ratio of lactate and ethanol is important for the optimum performance of AAB. As lactate and ethanol are individually supplied by lactic acid bacteria and yeasts during the initial phase of cocoa fermentation, respectively, this underlines the importance of a well-balanced microbial consortium for a successful fermentation process. Indeed, AAB performed the best and produced the largest amounts of acetate in mixed culture experiments when lactic acid bacteria and yeasts were both present. PMID:24837393

  20. Different Serum Free Fatty Acid Profiles in NAFLD Subjects and Healthy Controls after Oral Fat Load

    PubMed Central

    Gambino, Roberto; Bugianesi, Elisabetta; Rosso, Chiara; Mezzabotta, Lavinia; Pinach, Silvia; Alemanno, Natalina; Saba, Francesca; Cassader, Maurizio

    2016-01-01

    Background: Free fatty acid (FFA) metabolism can impact on metabolic conditions, such as obesity and nonalcoholic fatty liver disease (NAFLD). This work studied the increase in total FFA shown in NAFLD subjects to possibly characterize which fatty acids significantly accounted for the whole increase. Methods: 21 patients with NAFLD were selected according to specified criteria. The control group consisted of nine healthy subjects. All subjects underwent an oral standard fat load. Triglycerides; cholesterol; FFA; glucose and insulin were measured every 2 h with the determination of fatty acid composition of FFA. Results: higher serum FFA levels in NAFLD subjects are mainly due to levels of oleic, palmitic and linoleic acids at different times. Significant increases were shown for docosahexaenoic acid, linolenic acid, eicosatrienoic acid, and arachidonic acid, although this was just on one occasion. In the postprandial phase, homeostatic model assessment HOMA index positively correlated with the ω3/ω6 ratio in NAFLD patients. Conclusions: the higher serum levels of FFA in NAFLD subjects are mainly due to levels of oleic and palmitic acids which are the most abundant circulating free fatty acids. This is almost exactly corresponded with significant increases in linoleic acid. An imbalance in the n-3/n-6 fatty acids ratio could modulate postprandial responses with more pronounced effects in insulin-resistant subjects, such as NAFLD patients. PMID:27043543

  1. Insights into the Indian Peanut Genotypes for ahFAD2 Gene Polymorphism Regulating Its Oleic and Linoleic Acid Fluxes.

    PubMed

    Nawade, Bhagwat; Bosamia, Tejas C; Thankappan, Radhakrishnan; Rathnakumar, Arulthambi L; Kumar, Abhay; Dobaria, Jentilal R; Kundu, Rahul; Mishra, Gyan P

    2016-01-01

    In peanut (Arachis hypogaea L.), the customization of fatty acid profile is an evolving area to fulfill the nutritional needs in the modern market. A total of 174 peanut genotypes, including 167 Indian cultivars, 6 advanced breeding lines and "SunOleic95R"-a double mutant line, were investigated using AS-PCRs, CAPS and gene sequencing for the ahFAD2 allele polymorphism, along with its fatty acid compositions. Of these, 80 genotypes were found having substitution (448G>A) mutation only in ahFAD2A gene, while none recorded 1-bp insertion (441_442insA) mutation in ahFAD2B gene. Moreover, 22 wild peanut accessions found lacking both the mutations. Among botanical types, the ahFAD2A mutation was more frequent in ssp. hypogaea (89%) than in ssp. fastigiata (17%). This single allele mutation, found affecting not only oleic to linoleic acid fluxes, but also the composition of other fatty acids in the genotypes studied. Repeated use of a few selected genotypes in the Indian varietal development programs were also eminently reflected in its ahFAD2 allele polymorphism. Absence of known mutations in the wild-relatives indicated the possible origin of these mutations, after the allotetraploidization of cultivated peanut. The SNP analysis of both ahFAD2A and ahFAD2B genes, revealed haplotype diversity of 1.05% and 0.95%, while Ka/Ks ratio of 0.36 and 0.39, respectively, indicating strong purifying selection pressure on these genes. Cluster analysis, using ahFAD2 gene SNPs, showed presence of both mutant and non-mutant genotypes in the same cluster, which might be due the presence of ahFAD2 gene families. This investigation provided insights into the large number of Indian peanut genotypes, covering various aspects related to O/L flux regulation and ahFAD2 gene polymorphism. PMID:27610115

  2. Insights into the Indian Peanut Genotypes for ahFAD2 Gene Polymorphism Regulating Its Oleic and Linoleic Acid Fluxes

    PubMed Central

    Nawade, Bhagwat; Bosamia, Tejas C.; Thankappan, Radhakrishnan; Rathnakumar, Arulthambi L.; Kumar, Abhay; Dobaria, Jentilal R.; Kundu, Rahul; Mishra, Gyan P.

    2016-01-01

    In peanut (Arachis hypogaea L.), the customization of fatty acid profile is an evolving area to fulfill the nutritional needs in the modern market. A total of 174 peanut genotypes, including 167 Indian cultivars, 6 advanced breeding lines and “SunOleic95R”—a double mutant line, were investigated using AS-PCRs, CAPS and gene sequencing for the ahFAD2 allele polymorphism, along with its fatty acid compositions. Of these, 80 genotypes were found having substitution (448G>A) mutation only in ahFAD2A gene, while none recorded 1-bp insertion (441_442insA) mutation in ahFAD2B gene. Moreover, 22 wild peanut accessions found lacking both the mutations. Among botanical types, the ahFAD2A mutation was more frequent in ssp. hypogaea (89%) than in ssp. fastigiata (17%). This single allele mutation, found affecting not only oleic to linoleic acid fluxes, but also the composition of other fatty acids in the genotypes studied. Repeated use of a few selected genotypes in the Indian varietal development programs were also eminently reflected in its ahFAD2 allele polymorphism. Absence of known mutations in the wild-relatives indicated the possible origin of these mutations, after the allotetraploidization of cultivated peanut. The SNP analysis of both ahFAD2A and ahFAD2B genes, revealed haplotype diversity of 1.05% and 0.95%, while Ka/Ks ratio of 0.36 and 0.39, respectively, indicating strong purifying selection pressure on these genes. Cluster analysis, using ahFAD2 gene SNPs, showed presence of both mutant and non-mutant genotypes in the same cluster, which might be due the presence of ahFAD2 gene families. This investigation provided insights into the large number of Indian peanut genotypes, covering various aspects related to O/L flux regulation and ahFAD2 gene polymorphism. PMID:27610115

  3. Measurement of non-enteric emission fluxes of volatile fatty acids from a California dairy by solid phase micro-extraction with gas chromatography/mass spectrometry

    NASA Astrophysics Data System (ADS)

    Alanis, Phillip; Sorenson, Mark; Beene, Matt; Krauter, Charles; Shamp, Brian; Hasson, Alam S.

    Dairies are a major source of volatile organic compounds (VOCs) in California's San Joaquin Valley; a region that experiences high ozone levels during summer. Short-chain carboxylic acids, or volatile fatty acids (VFAs), are believed to make up a large fraction of VOC emissions from these facilities, although there are few studies to substantiate this. In this work, a method using a flux chamber coupled to solid phase micro-extraction (SPME) fibers followed by analysis using gas chromatography/mass spectrometry was developed to quantify emissions of six VFAs (acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid and 3-methyl butanoic acid) from non-enteric sources. The technique was then used to quantify VFA fluxes from a small dairy located on the campus of California State University Fresno. Both animal feed and animal waste are found to be major sources of VFAs, with acetic acid contributing 70-90% of emissions from the sources tested. Measured total acid fluxes during spring (with an average temperature of 20 °C) were 1.84 ± 0.01, 1.06 ± 0.08, (1.3 ± 0.5) × 10 -2, (1.7 ± 0.2) × 10 -2 and (1.2 ± 0.5) × 10 -2 g m -2 h -1 from silage, total mixed rations, flushing lane, open lot and lagoon sources, respectively. VFA emissions from the sources tested total 390 ± 80 g h -1. The data indicate high fluxes of VFAs from dairy facilities, but differences in the design and operation of dairies in the San Joaquin Valley as well as seasonal variations mean that additional measurements must be made to accurately determine emissions inventories for the region.

  4. Enhancement of free fatty acid production in Saccharomyces cerevisiae by control of fatty acyl-CoA metabolism.

    PubMed

    Chen, Liwei; Zhang, Jianhua; Lee, Jaslyn; Chen, Wei Ning

    2014-08-01

    Production of biofuels derived from microbial fatty acids has attracted great attention in recent years owing to their potential to replace petroleum-derived fuels. To be cost competitive with current petroleum fuel, flux toward the direct precursor fatty acids needs to be enhanced to approach high yields. Herein, fatty acyl-CoA metabolism in Saccharomyces cerevisiae was engineered to accumulate more free fatty acids (FFA). For this purpose, firstly, haploid S. cerevisiae double deletion strain △faa1△faa4 was constructed, in which the genes FAA1 and FAA4 encoding two acyl-CoA synthetases were deleted. Then the truncated version of acyl-CoA thioesterase ACOT5 (Acot5s) encoding Mus musculus peroxisomal acyl-CoA thioesterase 5 was expressed in the cytoplasm of the strain △faa1△faa4. The resulting strain △faa1△faa4 [Acot5s] accumulated more extracellular FFA with higher unsaturated fatty acid (UFA) ratio as compared to the wild-type strain and double deletion strain △faa1△faa4. The extracellular total fatty acids (TFA) in the strain △faa1△faa4 [Acot5s] increased to 6.43-fold as compared to the wild-type strain during the stationary phase. UFA accounted for 42 % of TFA in the strain △faa1△faa4 [Acot5s], while no UFA was detected in the wild-type strain. In addition, the expression of Acot5s in △faa1△faa4 restored the growth, which indicates that FFA may not be the reason for growth inhibition in the strain △faa1△faa4. RT-PCR results demonstrated that the de-repression of fatty acid synthesis genes led to the increase of extracellular fatty acids. The study presented here showed that through control of the acyl-CoA metabolism by deleting acyl-CoA synthetase and expressing thioesterase, more FFA could be produced in S. cerevisiae, demonstrating great potential for exploitation in the platform of microbial fatty acid-derived biofuels. PMID:24769906

  5. The Internal Anticipation of Sensory Action Effects: When Action Induces FFA and PPA Activity

    PubMed Central

    Kühn, Simone; Seurinck, Ruth; Fias, Wim; Waszak, Florian

    2010-01-01

    Voluntary action – in particular the ability to produce desired effects in the environment – is fundamental to human existence. According to ideomotor theory we can achieve goals in the environment by means of anticipating their outcomes. We aimed at providing neurophysiological evidence for the assumption that performing actions calls for the activation of brain areas associated with the sensory effects usually evoked by the actions. We conducted an fMRI study in which right and left button presses lead to the presentation of face and house pictures. We compared a baseline phase with the same phase after participants experienced the association between button presses and pictures. We found an increase in the parahippocampal place area (PPA) for the response that has been associated with house pictures and fusiform face area (FFA) for the response that has been coupled with face pictures. This observation constitutes support for ideomotor theory. PMID:20661462

  6. Association of Novel and Highly Diverse Acid-Tolerant Denitrifiers with N2O Fluxes of an Acidic Fen▿ †

    PubMed Central

    Palmer, Katharina; Drake, Harold L.; Horn, Marcus A.

    2010-01-01

    Wetlands are sources of denitrification-derived nitrous oxide (N2O). Thus, the denitrifier community of an N2O-emitting fen (pH 4.7 to 5.2) was investigated. N2O was produced and consumed to subatmospheric concentrations in unsupplemented anoxic soil microcosms. Total cell counts and most probable numbers of denitrifiers approximated 1011 cells·gDW−1 (where DW is dry weight) and 108 cells·gDW−1, respectively, in both 0- to 10-cm and 30- to 40-cm depths. Despite this uniformity, depth-related maximum reaction rate (vmax) values for denitrification in anoxic microcosms ranged from 1 to 24 and −19 to −105 nmol N2O h−1· gDW−1, with maximal values occurring in the upper soil layers. Denitrification was enhanced by substrates that might be formed via fermentation in anoxic microzones of soil. N2O approximated 40% of total nitrogenous gases produced at in situ pH, which was likewise the optimal pH for denitrification. Gene libraries of narG and nosZ (encoding nitrate reductase and nitrous oxide reductase, respectively) from fen soil DNA yielded 15 and 18 species-level operational taxonomic units, respectively, many of which displayed phylogenetic novelty and were not closely related to cultured organisms. Although statistical analyses of narG and nosZ sequences indicated that the upper 20 cm of soil contained the highest denitrifier diversity and species richness, terminal restriction fragment length polymorphism analyses of narG and nosZ revealed only minor differences in denitrifier community composition from a soil depth of 0 to 40 cm. The collective data indicate that the regional fen harbors novel, highly diverse, acid-tolerant denitrifier communities capable of complete denitrification and consumption of atmospheric N2O at in situ pH. PMID:20023077

  7. Beyond the FFA: The role of the ventral anterior temporal lobes in face processing.

    PubMed

    Collins, Jessica A; Olson, Ingrid R

    2014-08-01

    Extensive research has supported the existence of a specialized face-processing network that is distinct from the visual processing areas used for general object recognition. The majority of this work has been aimed at characterizing the response properties of the fusiform face area (FFA) and the occipital face area (OFA), which together are thought to constitute the core network of brain areas responsible for facial identification. Although accruing evidence has shown that face-selective patches in the ventral anterior temporal lobes (vATLs) are interconnected with the FFA and OFA, and that they play a role in facial identification, the relative contribution of these brain areas to the core face-processing network has remained unarticulated. Here we review recent research critically implicating the vATLs in face perception and memory. We propose that current models of face processing should be revised such that the ventral anterior temporal lobes serve a centralized role in the visual face-processing network. We speculate that a hierarchically organized system of face processing areas extends bilaterally from the inferior occipital gyri to the vATLs, with facial representations becoming increasingly complex and abstracted from low-level perceptual features as they move forward along this network. The anterior temporal face areas may serve as the apex of this hierarchy, instantiating the final stages of face recognition. We further argue that the anterior temporal face areas are ideally suited to serve as an interface between face perception and face memory, linking perceptual representations of individual identity with person-specific semantic knowledge. PMID:24937188

  8. Beyond the FFA: The Role of the Ventral Anterior Temporal Lobes in Face Processing

    PubMed Central

    Collins, Jessica A.; Olson, Ingrid R.

    2014-01-01

    Extensive research has supported the existence of a specialized face-processing network that is distinct from the visual processing areas used for general object recognition. The majority of this work has been aimed at characterizing the response properties of the fusiform face area (FFA) and the occipital face area (OFA), which together are thought to constitute the core network of brain areas responsible for facial identification. Although accruing evidence has shown that face-selective patches in the ventral anterior temporal lobes (vATLs) are interconnected with the FFA and OFA, and that they play a role in facial identification, the relative contribution of these brain areas to the core face-processing network has remained unarticulated. Here we review recent research critically implicating the vATLs in face perception and memory. We propose that current models of face processing should be revised such that the ventral anterior temporal lobes serve a centralized role in the visual face-processing network. We speculate that a hierarchically organized system of face processing areas extends bilaterally from the inferior occipital gyri to the vATLs, with facial representations becoming increasingly complex and abstracted from low-level perceptual features as they move forward along this network. The anterior temporal face areas may serve as the apex of this hierarchy, instantiating the final stages of face recognition. We further argue that the anterior temporal face areas are ideally suited to serve as an interface between face perception and face memory, linking perceptual representations of individual identity with person-specific semantic knowledge. PMID:24937188

  9. Behaviour and fluxes of natural radionuclides in the production process of a phosphoric acid plant.

    PubMed

    Bolívar, J P; Martín, J E; García-Tenorio, R; Pérez-Moreno, J P; Mas, J L

    2009-02-01

    In recent years there has been an increasing awareness of the occupational and public hazards of the radiological impact of non-nuclear industries which process materials containing naturally occurring radionuclides. These include the industries devoted to the production of phosphoric acid by treating sedimentary phosphate rocks enriched in radionuclides from the uranium series. With the aim of evaluating the radiological impact of a phosphoric acid factory located in the south-western Spain, the distribution and levels of radionuclides in the materials involved in its production process have been analysed. In this way, it is possible to asses the flows of radionuclides at each step and to locate those points where a possible radionuclide accumulation could be produced. A set of samples collected along the whole production process were analysed to determine their radionuclide content by both alpha-particle and gamma spectrometry techniques. The radionuclide fractionation steps and enrichment sources have been located, allowing the establishment of their mass (activity) balances per year. PMID:19064324

  10. An Examination of Middle School Enrollment in Agricultural Education and Membership in the National FFA Organization in the United States. Summary of Research 73.

    ERIC Educational Resources Information Center

    Rossetti, Rosemarie; And Others

    The status of middle and junior high school agricultural education and Future Farmers of America (FFA) programs in the United States was the focus of a study. Data were collected through a census of the FFA executive secretaries and a survey of a purposive sample of 27 successful middle or junior high school agricultural education programs in 9…

  11. Study of UltraHigh Performance Supercritical Fluid Chromatography to measure free fatty acids with out fatty acid ester preparation.

    PubMed

    Ashraf-Khorassani, M; Isaac, G; Rainville, P; Fountain, K; Taylor, L T

    2015-08-01

    Most lipids are best characterized by their fatty acids which may differ in (a) chain length, (b) degree of unsaturation, (c) configuration and position of the double bonds, and (d) the presence of other functionalities. Thus, a fast, simple, and quantitative analytical technique to determine naturally occurring free fatty acids (FFA) in different samples is very important. Just as for saponified acylglycerols, the determination of FFA's has generally been carried out by high resolution gas chromatography (HRGC). The use of an open tubular capillary column coupled with a flame ionization or mass spectrometric detector provides for both high resolution and quantification of FFA's but only after conversion of all free fatty acids to fatty acid methyl esters (FAME) or pentafluorobenzyl esters. Unfortunately, volatilization of labile ester derivatives of mono- and poly-unsaturated FFA's can cause both thermal degradation and isomerization of the fatty acid during HRGC. The employment of a second generation instrument (here referred to as UltraHigh Performance Supercritical Fluid Chromatograph, UHPSFC) with high precision for modified flow and repeated back pressure adjustment in conjunction with sub-2μm various bonded silica particles (coupled with evaporative light scattering, ELSD, and mass spectrometric, MS, detection) for separation and detection of the following mixtures is described: (a) 31 free fatty acids, (b) isomeric FFA's, and (c) lipophilic materials in two real world fish oil samples. Limits of detection for FFA's via UHPSFC/MS and UHPSFC/ELSD versus detection of FAME's via HRGC/MS are quantitatively compared. PMID:26093119

  12. The Pharmacology and Function of Receptors for Short-Chain Fatty Acids.

    PubMed

    Bolognini, Daniele; Tobin, Andrew B; Milligan, Graeme; Moss, Catherine E

    2016-03-01

    Despite some blockbuster G protein-coupled receptor (GPCR) drugs, only a small fraction (∼ 15%) of the more than 390 nonodorant GPCRs have been successfully targeted by the pharmaceutical industry. One way that this issue might be addressed is via translation of recent deorphanization programs that have opened the prospect of extending the reach of new medicine design to novel receptor types with potential therapeutic value. Prominent among these receptors are those that respond to short-chain free fatty acids of carbon chain length 2-6. These receptors, FFA2 (GPR43) and FFA3 (GPR41), are each predominantly activated by the short-chain fatty acids acetate, propionate, and butyrate, ligands that originate largely as fermentation by-products of anaerobic bacteria in the gut. However, the presence of FFA2 and FFA3 on pancreatic β-cells, FFA3 on neurons, and FFA2 on leukocytes and adipocytes means that the biologic role of these receptors likely extends beyond the widely accepted role of regulating peptide hormone release from enteroendocrine cells in the gut. Here, we review the physiologic roles of FFA2 and FFA3, the recent development and use of receptor-selective pharmacological tool compounds and genetic models available to study these receptors, and present evidence of the potential therapeutic value of targeting this emerging receptor pair. PMID:26719580

  13. Evidence for differential action of indoleacetic acid upon ion fluxes in single cells of Petroselinum sativum.

    PubMed

    Bentrup, F W; Pfrüner, H; Wagner, G

    1973-12-01

    The apparent influx of (36)Cl(-) and (86)Rb(+)/K(+) into cells from the higher plant Petroselinum sativum has been measured during the presence and absence in the culture medium of indolacetic acid (IAA) which is an essential auxin of these cells. While 10(-5) M IAA did not significantly affect the influx of (86)Rb(+)/K(+), it substantially reduced that of (36)Cl(-), i.e. by a factor 0.25 within 30 min. This differential action of IAA, which holds for a reasonable range of external pH, is assumed to bear on current hypotheses that the primary events of auxin action involve plasmalemma functions. PMID:24474466

  14. Relationship of Student Characteristics and Program Policies to Participation in FFA. A Digest of a Ph. D. Dissertation.

    ERIC Educational Resources Information Center

    Welton, Richard F.; Bender, Ralph E.

    This report is a summary of a doctoral thesis concerning the relationship of Future Farmers of America (FAA) Chapter programs and the characteristics of vocational agricultural students participating in FFA activities. Based on data collected from 109 vocational agriculture departments, findings are summarized according to: (1) the attributes of…

  15. Similar spatial patterns of neural coding of category selectivity in FFA and VWFA under different attention conditions.

    PubMed

    Xu, Guifang; Jiang, Yi; Ma, Lifei; Yang, Zhi; Weng, Xuchu

    2012-04-01

    It has long been debated whether attention alters the categorical selectivity in regions such as the fusiform face area (FFA) and the visual word form area (VWFA). We addressed this issue by examining whether the spatial pattern of neural representations for certain stimulus categories in these regions would change under different attention conditions. Faces, Chinese characters, and textures were presented in a block design fMRI experiment where participants in different runs attended to the stimuli under different conditions of attention. After localizing regions of interest (ROIs) in FFA and VWFA using general linear models, we performed spatial pattern analyses to examine both within- and cross-condition classification in these ROIs. The within-condition results replicated previous findings showing significant classification accuracy reduction when there was less attention compared with more attention. Critically, cross-condition classification in both FFA and VWFA revealed significantly above-chance accuracy for all stimulus categories, suggesting similar spatial neural representations across different attention conditions. Further strengthening this conclusion, when the contrast-to-noise ratio (CNR) of the signals was adjusted to increase signal strength, cross-condition classification accuracy for faces in FFA and for Chinese characters in VWFA improved significantly, even approaching within-condition accuracy. This indicates that attention does not modulate the spatial pattern of neural representations involved in category selectivity, but only changes the signal strength relative to the noise level. PMID:22306521

  16. A Mixed Method Study of Positional Leadership of North Dakota 4-H Ambassador and State FFA Officer Alumni

    ERIC Educational Resources Information Center

    Peterson, Nels Milan

    2010-01-01

    The purpose of this mixed method study was to determine the positional leadership of North Dakota 4-H and FFA leadership alumni. This study determined the influence of youth development programs on statewide leadership alumni (those who served from 1970 to 2000) and community leadership roles as adults. Former North Dakota 4-H Ambassador Alumni…

  17. Crystal Chemistry of the Potassium and Rubidium Uranyl Borate Families Derived from Boric Acid Fluxes

    SciTech Connect

    Wang, Shuao; Alekseev, Evgeny V.; Stritzinger, Jared T.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.

    2010-07-19

    The reaction of uranyl nitrate with a large excess of molten boric acid in the presence of potassium or rubidium nitrate results in the formation of three new potassium uranyl borates, K{sub 2}[(UO{sub 2}){sub 2}B{sub 12}O{sub 19}(OH){sub 4}]·0.3H{sub 2}O (KUBO-1), K[(UO{sub 2}){sub 2}B{sub 10}O{sub 15}(OH){sub 5}] (KUBO-2), and K[(UO{sub 2}){sub 2}B{sub 10}O{sub 16}(OH){sub 3}]·0.7H{sub 2}O (KUBO-3) and two new rubidium uranyl borates Rb{sub 2}[(UO{sub 2}){sub 2}B{sub 13}O{sub 20}(OH){sub 5}] (RbUBO-1) and Rb[(UO{sub 2}){sub 2}B{sub 10}O{sub 16}(OH){sub 3}]·0.7H{sub 2}O (RbUBO-2). The latter is isotypic with KUBO-3. These compounds share a common structural motif consisting of a linear uranyl, UO{sub 2}{sup 2+}, cation surrounded by BO{sub 3} triangles and BO{sub 4} tetrahedra to create an UO{sub 8} hexagonal bipyramidal environment around uranium. The borate anions bridge between uranyl units to create sheets. Additional BO{sub 3} triangles extend from the polyborate layers and are directed approximately perpendicular to the sheets. All of these compounds adopt layered structures. With the exception of KUBO-1, the structures are all centrosymmetric. All of these compounds fluoresce when irradiated with long-wavelength UV light. The fluorescence spectrum yields well-defined vibronically coupled charge-transfer features.

  18. RNA-Seq analysis and targeted mutagenesis for improved free fatty acid production in an engineered cyanobacterium

    PubMed Central

    2013-01-01

    Background High-energy-density biofuels are typically derived from the fatty acid pathway, thus establishing free fatty acids (FFAs) as important fuel precursors. FFA production using photosynthetic microorganisms like cyanobacteria allows for direct conversion of carbon dioxide into fuel precursors. Recent studies investigating cyanobacterial FFA production have demonstrated the potential of this process, yet FFA production was also shown to have negative physiological effects on the cyanobacterial host, ultimately limiting high yields of FFAs. Results Cyanobacterial FFA production was shown to generate reactive oxygen species (ROS) and lead to increased cell membrane permeability. To identify genetic targets that may mitigate these toxic effects, RNA-seq analysis was used to investigate the host response of Synechococcus elongatus PCC 7942. Stress response, nitrogen metabolism, photosynthesis, and protein folding genes were up-regulated during FFA production while genes involved in carbon and hydrogen metabolisms were down-regulated. Select genes were targeted for mutagenesis to confirm their role in mitigating FFA toxicity. Gene knockout of two porins and the overexpression of ROS-degrading proteins and hypothetical proteins reduced the toxic effects of FFA production, allowing for improved growth, physiology, and FFA yields. Comparative transcriptomics, analyzing gene expression changes associated with FFA production and other stress conditions, identified additional key genes involved in cyanobacterial stress response. Conclusions A total of 15 gene targets were identified to reduce the toxic effects of FFA production. While single-gene targeted mutagenesis led to minor increases in FFA production, the combination of these targeted mutations may yield additional improvement, advancing the development of high-energy-density fuels derived from cyanobacteria. PMID:23919451

  19. Aging Impairs Myocardial Fatty Acid and Ketone Oxidation and Modifies Cardiac Functional and Metabolic Responses to Insulin in Mice

    SciTech Connect

    Hyyti, Outi M.; Ledee, Dolena; Ning, Xue-Han; Ge, Ming; Portman, Michael A.

    2010-07-02

    Aging presumably initiates shifts in substrate oxidation mediated in part by changes in insulin sensitivity. Similar shifts occur with cardiac hypertrophy and may contribute to contractile dysfunction. We tested the hypothesis that aging modifies substrate utilization and alters insulin sensitivity in mouse heart when provided multiple substrates. In vivo cardiac function was measured with microtipped pressure transducers in the left ventricle from control (4–6 mo) and aged (22–24 mo) mice. Cardiac function was also measured in isolated working hearts along with substrate and anaplerotic fractional contributions to the citric acid cycle (CAC) by using perfusate containing 13C-labeled free fatty acids (FFA), acetoacetate, lactate, and unlabeled glucose. Stroke volume and cardiac output were diminished in aged mice in vivo, but pressure development was preserved. Systolic and diastolic functions were maintained in aged isolated hearts. Insulin prompted an increase in systolic function in aged hearts, resulting in an increase in cardiac efficiency. FFA and ketone flux were present but were markedly impaired in aged hearts. These changes in myocardial substrate utilization corresponded to alterations in circulating lipids, thyroid hormone, and reductions in protein expression for peroxisome proliferator-activated receptor (PPAR)α and pyruvate dehydrogenase kinase (PDK)4. Insulin further suppressed FFA oxidation in the aged. Insulin stimulation of anaplerosis in control hearts was absent in the aged. The aged heart shows metabolic plasticity by accessing multiple substrates to maintain function. However, fatty acid oxidation capacity is limited. Impaired insulin-stimulated anaplerosis may contribute to elevated cardiac efficiency, but may also limit response to acute stress through depletion of CAC intermediates.

  20. Flufenamic acid prevents behavioral manifestations of salicylate-induced tinnitus in the rat

    PubMed Central

    Ustundag, Yasemin; Bulut, Funda; Demir, Caner Feyzi; Bal, Ali

    2016-01-01

    Introduction Tinnitus is defined as a phantom auditory sensation, the perception of sound in the absence of external acoustic stimulation. Given that flufenamic acid (FFA) blocks TRPM2 cation channels, resulting in reduced neuronal excitability, we aimed to investigate whether FFA suppresses the behavioral manifestation of sodium salicylate (SSA)-induced tinnitus in rats. Material and methods Tinnitus was evaluated using a conditioned lick suppression model of behavioral testing. Thirty-one Wistar rats, randomly divided into four treatment groups, were trained and tested in the behavioral experiment: (1) control group: DMSO + saline (n = 6), (2) SSA group: DMSO + SSA (n = 6), (3) FFA group: FFA (66 mg/kg bw) + saline (n = 9), (4) FFA + SSA group: FFA (66 mg/kg bw) + SSA (400 mg/kg bw) (n = 10). Localization of TRPM2 to the plasma membrane of cochlear nucleus neurons was demonstrated by confocal microscopy. Results Pavlovian training resulted in strong suppression of licking, having a mean value of 0.05 ±0.03 on extinction day 1, which is below the suppression training criterion level of 0.20 in control tinnitus animals. The suppression rate for rats having both FFA (66 mg/kg bw) and SSA (400 mg/kg bw) injections was significantly lower than that for the rats having SSA injections (p < 0.01). Conclusions We suggest that SSA-induced tinnitus could possibly be prevented by administration of a TRPM2 ion channel antagonist, FFA at 66 mg/kg bw. PMID:26925138

  1. Theoretical Study on Free Fatty Acid Elimination Mechanism for Waste Cooking Oils to Biodiesel over Acid Catalyst.

    PubMed

    Wang, Kai; Zhang, Xiaochao; Zhang, Jilong; Zhang, Zhiqiang; Fan, Caimei; Han, Peide

    2016-05-01

    A theoretical investigation on the esterification mechanism of free fatty acid (FFA) in waste cooking oils (WCOs) has been carried out using DMol(3) module based on the density functional theory (DFT). Three potential pathways of FFA esterification reaction are designed to achieve the formation of fatty acid methyl ester (FAME), and calculated results show that the energy barrier can be efficiently reduced from 88.597kcal/mol to 15.318kcal/mol by acid catalyst. The molar enthalpy changes (ΔrHm°) of designed pathways are negative, indicating that FFA esterification reaction is an exothermic process. The obtained favorable energy pathway is: H(+) firstly activates FFA, then the intermediate combines with methanol to form a tetrahedral structure, and finally, producing FAME after removing a water molecule. The rate-determining step is the combination of the activated FFA with methanol, and the activation energy is about 11.513kcal/mol at 298.15K. Our results should provide basic and reliable theoretical data for further understanding the elimination mechanism of FFA over acid catalyst in the conversion of WCOs to biodiesel products. PMID:27023919

  2. Boric acid flux synthesis, structure and magnetic property of MB12O14(OH)10 (M=Mn, Fe, Zn)

    NASA Astrophysics Data System (ADS)

    Yang, Dingfeng; Cong, Rihong; Gao, Wenliang; Yang, Tao

    2013-05-01

    Three new borates MB12O14(OH)10 (M=Mn, Fe, Zn) have been synthesized by boric acid flux methods, which are isotypic to NiB12O14(OH)10. Single-crystal XRD was performed to determine the crystal structures in detail. They all crystallize in the monoclinic space group P21/c. The size of MO6 (M=Mg, Mn, Fe, Co, Ni, Zn) octahedron shows a good agreement with the Shannon effective ionic radii of M2+. Magnetic measurements indicate MnB12O14(OH)10 is antiferromagnetic without a long-range ordering down to 2 K. The values of its magnetic superexchange constants were evaluated by DFT calculations, which explain the observed magnetic behavior. The UV-vis diffuse reflectance spectrum of ZnB12O14(OH)10 suggests a band gap ˜4.6 eV. DFT calculations indicate it has a direct band gap 4.9 eV. The optical band gap is contributed by charge transfers from the occupied O 2p to the unoccupied Zn 4s states.

  3. Retinoic Acid Prevents Disruption of Blood-Spinal Cord Barrier by Inducing Autophagic Flux After Spinal Cord Injury.

    PubMed

    Zhou, Yulong; Zheng, Binbin; Ye, Libing; Zhang, Hongyu; Zhu, Sipin; Zheng, Xiaomeng; Xia, Qinghai; He, Zili; Wang, Qingqing; Xiao, Jian; Xu, Huazi

    2016-04-01

    Spinal cord injury (SCI) induces the disruption of the blood-spinal cord barrier (BSCB), which leads to infiltration of blood cells, inflammatory responses and neuronal cell death, with subsequent development of spinal cord secondary damage. Recent reports pointed to an important role of retinoic acid (RA), the active metabolite of the vitamin A, in the induction of the blood-brain barrier (BBB) during human and mouse development, however, it is unknown whether RA plays a role in maintaining BSCB integrity under the pathological conditions such as SCI. In this study, we investigated the BSCB protective role of RA both in vivo and in vitro and demonstrated that autophagy are involved in the BSCB protective effect of RA. Our data show that RA attenuated BSCB permeability and also attenuated the loss of tight junction molecules such as P120, β-catenin, Occludin and Claudin5 after injury in vivo as well as in brain microvascular endothelial cells. In addition, RA administration improved functional recovery of the rat model of trauma. We also found that RA could significantly increase the expression of LC3-II and decrease the expression of p62 both in vivo and in vitro. Furthermore, combining RA with the autophagy inhibitor chloroquine (CQ) partially abolished its protective effect on the BSCB and exacerbated the loss of tight junctions. Together, our studies indicate that RA improved functional recovery in part by the prevention of BSCB disruption via the activation of autophagic flux after SCI. PMID:26582233

  4. Methane Suppression: The Impacts of Fe(III) and Humic Acids on Net Methane Flux from Arctic Tundra Wetlands in Alaska and Finland (Invited)

    NASA Astrophysics Data System (ADS)

    Lipson, D.; Miller, K.; Lai, C.

    2013-12-01

    Arctic soils contain large reservoirs of carbon (C) that are vulnerable to loss from climatic warming. However the potential global impacts of this C depend on whether it is lost primarily in the form of methane (CH4) or carbon dioxide (CO2), two gases with very different greenhouse warming potentials. In anaerobic environments, the relative production of CH4 vs. CO2 may be controlled by the presence of alternative terminal electron acceptors, which allow more thermodynamically favorable anaerobic respiratory pathways to dominate over methanogenesis. This work investigated how the addition of terminal electron acceptors, ferric iron (Fe(III)) and humic acids, affected net CH4 fluxes from high-latitude wetland ecosystems. We conducted two manipulative field experiments in Barrow, Alaska (71° N) and Finnish Lapland (69° N). The ecosystem in Barrow was known from previous studies to be rich in Fe(III) and to harbor a microbial community that is dominated by Fe(III)- and humic acid-reducing microorganisms. The role of these alternative electron acceptors had not previously been studied at the Finnish site. CH4 and CO2 fluxes were measured using a portable trace gas analyzer from experimental plots, before and after amendments with Fe(III) (in the chelated form, ferric nitrilotriacetic acid), humic acids, or water as a control. Both in the ecosystem with permafrost and naturally high levels of soil Fe (Barrow, AK) and in the ecosystem with no permafrost and naturally low levels of soil Fe (Petsikko, Finland), the addition of the alternative electron acceptors Fe(III) and humic acids significantly reduced net CH4 flux. CO2 fluxes were not significantly altered by the treatments. The reduction in CH4 flux persisted for at least several weeks post-treatment. There was no significant difference between the reduction caused by humic acids versus that from Fe(III). These results show that the suppression of CH4 flux by Fe(III) and humic acids is a widespread phenomenon that

  5. Control analysis of lipid biosynthesis in tissue cultures from oil crops shows that flux control is shared between fatty acid synthesis and lipid assembly.

    PubMed Central

    Ramli, Umi S; Baker, Darren S; Quant, Patti A; Harwood, John L

    2002-01-01

    Top-Down (Metabolic) Control Analysis (TDCA) was used to examine, quantitatively, lipid biosynthesis in tissue cultures from two commercially important oil crops, olive (Olea europaea L.) and oil palm (Elaeis guineensis Jacq.). A conceptually simplified system was defined comprising two blocks of reactions: fatty acid synthesis (Block A) and lipid assembly (Block B), which produced and consumed, respectively, a common and unique system intermediate, cytosolic acyl-CoA. We manipulated the steady-state levels of the system intermediate by adding exogenous oleic acid and, using two independent assays, measured the effect of the addition on the system fluxes (J(A) and J(B)). These were the rate of incorporation of radioactivity: (i) through Block A from [1-(14)C]acetate into fatty acids and (ii) via Block B from [U-(14)C]glycerol into complex lipids respectively. The data showed that fatty acid formation (Block A) exerted higher control than lipid assembly (Block B) in both tissues with the following group flux control coefficients (C):(i) Oil palm: *C(J(TL))(BlkA)=0.64+/-0.05 and *C(J(TL))(BlkB)=0.36+/-0.05(ii) Olive: *C(J(TL))(BlkA)=0.57+/-0.10 and *C(J(TL))(BlkB)=0.43+/-0.10where *C indicates the group flux control coefficient over the lipid biosynthesis flux (J(TL)) and the subscripts BlkA and BlkB refer to defined blocks of the system, Block A and Block B. Nevertheless, because both parts of the lipid biosynthetic pathway exert significant flux control, we suggest strongly that manipulation of single enzyme steps will not affect product yield appreciably. The present study represents the first use of TDCA to examine the overall lipid biosynthetic pathway in any tissue, and its findings are of immediate academic and economic relevance to the yield and nutritional quality of oil crops. PMID:12023882

  6. Regulation of hypothalamic-pituitary-adrenal axis by circulating free fatty acids in male Wistar rats: role of individual free fatty acids.

    PubMed

    Oh, Young Taek; Kim, Jinyub; Kang, Insug; Youn, Jang H

    2014-03-01

    We previously showed that a fall in the plasma free fatty acid (FFA) level increases plasma corticosterone levels in rats by activating the hypothalamic-pituitary-adrenal axis. In the present study, we tested whether this regulation is mediated by specific or all species of FFAs. Nicotinic acid (NA) (30 μmol/h) was infused in rats to decrease plasma FFAs and increase plasma ACTH and corticosterone. The NA infusion was combined with an infusion of lipids with different FFA compositions to selectively prevent falls in individual FFA levels; coconut, olive, and safflower oils (n = 7 for each), which are predominantly (>70%) composed of saturated, monounsaturated (oleic acid), and polyunsaturated (linoleic acid) FFAs, respectively, were used. At an infusion rate (0.1 g/h) that only partially prevented a fall in the total FFA level, coconut oil, but not olive or safflower oil, completely prevented NA-induced increases in plasma ACTH or corticosterone, suggesting that these responses are mainly mediated by saturated FFAs. In addition, quantification of individual FFA species in the blood using FFA-specific fluorescent probes revealed that plasma corticosterone and ACTH correlated significantly with plasma palmitate but not with other FFAs, such as oleate, linoleate, or arachidonate. Taken together, our data suggest that the regulation of the hypothalamic-pituitary-adrenal axis by FFAs is mainly mediated by the saturated fatty acid palmitate, but not by unsaturated fatty acids, such as oleate and linoleate. PMID:24424035

  7. Acid soldering flux poisoning

    MedlinePlus

    ... Concepts and Clinical Practice . 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 158. Mirkin DB. Benzene and ... Poisoning and Drug Overdose . 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 94. Wax PM, Yarema M. ...

  8. Eicosopentaneoic Acid and Other Free Fatty Acid Receptor Agonists Inhibit Lysophosphatidic Acid- and Epidermal Growth Factor-Induced Proliferation of Human Breast Cancer Cells

    PubMed Central

    Hopkins, Mandi M.; Zhang, Zhihong; Liu, Ze; Meier, Kathryn E.

    2016-01-01

    Many key actions of ω-3 (n-3) fatty acids have recently been shown to be mediated by two G protein-coupled receptors (GPCRs) in the free fatty acid receptor (FFAR) family, FFA1 (GPR40) and FFA4 (GPR120). n-3 Fatty acids inhibit proliferation of human breast cancer cells in culture and in animals. In the current study, the roles of FFA1 and FFA4 were investigated. In addition, the role of cross-talk between GPCRs activated by lysophosphatidic acid (LPA), and the tyrosine kinase receptor activated by epidermal growth factor (EGF), was examined. In MCF-7 and MDA-MB-231 human breast cancer cell lines, both LPA and EGF stimulated proliferation, Erk activation, Akt activation, and CCN1 induction. LPA antagonists blocked effects of LPA and EGF on proliferation in MCF-7 and MDA-MB-231, and on cell migration in MCF-7. The n-3 fatty acid eicosopentaneoic acid inhibited LPA- and EGF-induced proliferation in both cell lines. Two synthetic FFAR agonists, GW9508 and TUG-891, likewise inhibited LPA- and EGF-induced proliferation. The data suggest a major role for FFA1, which was expressed by both cell lines. The results indicate that n-3 fatty acids inhibit breast cancer cell proliferation via FFARs, and suggest a mechanism involving negative cross-talk between FFARS, LPA receptors, and EGF receptor. PMID:26821052

  9. Free fatty-acid uptake by isolated rat hepatocytes.

    PubMed

    Renaud, G; Bouma, M E; Foliot, A; Infante, R

    1985-11-01

    In isolated rat hepatocytes, the rate of palmitic acid binding and uptake is directly related to the concentration of free fatty acid (FFA) in the medium. After their entry into the cell, FFA are immediately incorporated into cellular phospholipids and triglycerides and no accumulation of free fatty acids can be demonstrated inside the cell. The rate of free fatty-acid uptake remains unchanged after incubation in a 2 mM KCN containing medium, indicating that in the range of fatty-acid concentrations used in this study, this phenomenon does not require energy. PMID:2421669

  10. Novel free fatty acid receptor 1 (GPR40) agonists based on 1,3,4-thiadiazole-2-carboxamide scaffold.

    PubMed

    Krasavin, Mikhail; Lukin, Alexey; Zhurilo, Nikolay; Kovalenko, Alexey; Zahanich, Ihor; Zozulya, Sergey; Moore, Daniel; Tikhonova, Irina G

    2016-07-01

    Free fatty acid receptor 1 (FFA1), previously known as GPR40 is a G protein-coupled receptor and a new target for treatment of type 2 diabetes. Two series of FFA1 agonists utilizing a 1,3,4-thiadiazole-2-caboxamide scaffold were synthetized. Both series offered significant improvement of the potency compared to the previously described 1,3,4-thiadiazole-based FFA1 agonists and high selectivity for FFA1. Molecular docking predicts new aromatic interactions with the receptor that improve agonist potency. The most potent compounds from both series were profiled for in vitro ADME properties (plasma and metabolic stability, LogD, plasma protein binding, hERG binding and CYP inhibition). One series suffered very rapid degradation in plasma and in presence of mouse liver microsomes. However, the other series delivered a lead compound that displayed a reasonable ADME profile together with the improved FFA1 potency. PMID:27229618

  11. Implementation plan for liquid low-level radioactive waste systems under the FFA for fiscal years 1996 and 1997 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    SciTech Connect

    1996-06-01

    This document is the fourth annual revision of the plans and schedules for implementing the Federal Facility Agreement (FFA) compliance program, originally submitted in 1992 as ES/ER-17&D1, Federal Facility Agreement Plans and Schedules for Liquid Low-Level Radioactive Waste Tank Systems at Oak Ridge National Laboratory, Oak Ridge, Tennessee. This document summarizes the progress that has been made to date implementing the plans and schedules for meeting the FFA commitments for the Liquid Low-Level Waste (LLLW) System at Oak Ridge National Laboratory (ORNL). In addition, this document lists FFA activities planned for FY 1997. Information presented in this document provides a comprehensive summary to facilitate understanding of the FFA compliance program for LLLW tank systems and to present plans and schedules associated with remediation, through the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) process, of LLLW tank systems that have been removed from service.

  12. Abscisic Acid Flux Alterations Result in Differential Abscisic Acid Signaling Responses and Impact Assimilation Efficiency in Barley under Terminal Drought Stress1[C][W][OPEN

    PubMed Central

    Seiler, Christiane; Harshavardhan, Vokkaliga T.; Reddy, Palakolanu S.; Hensel, Götz; Kumlehn, Jochen; Eschen-Lippold, Lennart; Rajesh, Kalladan; Korzun, Viktor; Wobus, Ulrich; Lee, Justin; Selvaraj, Gopalan; Sreenivasulu, Nese

    2014-01-01

    Abscisic acid (ABA) is a central player in plant responses to drought stress. How variable levels of ABA under short-term versus long-term drought stress impact assimilation and growth in crops is unclear. We addressed this through comparative analysis, using two elite breeding lines of barley (Hordeum vulgare) that show senescence or stay-green phenotype under terminal drought stress and by making use of transgenic barley lines that express Arabidopsis (Arabidopsis thaliana) 9-cis-epoxycarotenoid dioxygenase (AtNCED6) coding sequence or an RNA interference (RNAi) sequence of ABA 8′-hydroxylase under the control of a drought-inducible barley promoter. The high levels of ABA and its catabolites in the senescing breeding line under long-term stress were detrimental for assimilate productivity, whereas these levels were not perturbed in the stay-green type that performed better. In transgenic barley, drought-inducible AtNCED expression afforded temporal control in ABA levels such that the ABA levels rose sooner than in wild-type plants but also subsided, unlike as in the wild type , to near-basal levels upon prolonged stress treatment due to down-regulation of endogenous HvNCED genes. Suppressing of ABA catabolism with the RNA interference approach of ABA 8′-hydroxylase caused ABA flux during the entire period of stress. These transgenic plants performed better than the wild type under stress to maintain a favorable instantaneous water use efficiency and better assimilation. Gene expression analysis, protein structural modeling, and protein-protein interaction analyses of the members of the PYRABACTIN RESISTANCE1/PYRABACTIN RESISTANCE1-LIKE/REGULATORY COMPONENT OF ABA RECEPTORS, TYPE 2C PROTEIN PHOSPHATASE Sucrose non-fermenting1-related protein kinase2, and ABA-INSENSITIVE5/ABA-responsive element binding factor family identified specific members that could potentially impact ABA metabolism and stress adaptation in barley. PMID:24610749

  13. Regulation of adipose branched-chain amino acid catabolism enzyme expression and cross-adipose amino acid flux in human obesity

    PubMed Central

    Lackey, Denise E.; Lynch, Christopher J.; Olson, Kristine C.; Mostaedi, Rouzbeh; Ali, Mohamed; Smith, William H.; Karpe, Fredrik; Humphreys, Sandy; Bedinger, Daniel H.; Dunn, Tamara N.; Thomas, Anthony P.; Oort, Pieter J.; Kieffer, Dorothy A.; Amin, Rajesh; Bettaieb, Ahmed; Haj, Fawaz G.; Permana, Paska; Anthony, Tracy G.

    2013-01-01

    Elevated blood branched-chain amino acids (BCAA) are often associated with insulin resistance and type 2 diabetes, which might result from a reduced cellular utilization and/or incomplete BCAA oxidation. White adipose tissue (WAT) has become appreciated as a potential player in whole body BCAA metabolism. We tested if expression of the mitochondrial BCAA oxidation checkpoint, branched-chain α-ketoacid dehydrogenase (BCKD) complex, is reduced in obese WAT and regulated by metabolic signals. WAT BCKD protein (E1α subunit) was significantly reduced by 35–50% in various obesity models (fa/fa rats, db/db mice, diet-induced obese mice), and BCKD component transcripts significantly lower in subcutaneous (SC) adipocytes from obese vs. lean Pima Indians. Treatment of 3T3-L1 adipocytes or mice with peroxisome proliferator-activated receptor-γ agonists increased WAT BCAA catabolism enzyme mRNAs, whereas the nonmetabolizable glucose analog 2-deoxy-d-glucose had the opposite effect. The results support the hypothesis that suboptimal insulin action and/or perturbed metabolic signals in WAT, as would be seen with insulin resistance/type 2 diabetes, could impair WAT BCAA utilization. However, cross-tissue flux studies comparing lean vs. insulin-sensitive or insulin-resistant obese subjects revealed an unexpected negligible uptake of BCAA from human abdominal SC WAT. This suggests that SC WAT may not be an important contributor to blood BCAA phenotypes associated with insulin resistance in the overnight-fasted state. mRNA abundances for BCAA catabolic enzymes were markedly reduced in omental (but not SC) WAT of obese persons with metabolic syndrome compared with weight-matched healthy obese subjects, raising the possibility that visceral WAT contributes to the BCAA metabolic phenotype of metabolically compromised individuals. PMID:23512805

  14. Flux control exerted by mitochondrial outer membrane carnitine palmitoyltransferase over beta-oxidation, ketogenesis and tricarboxylic acid cycle activity in hepatocytes isolated from rats in different metabolic states.

    PubMed Central

    Drynan, L; Quant, P A; Zammit, V A

    1996-01-01

    The Flux Control Coefficients of mitochondrial outer membrane carnitine palmitoyltransferase (CPT I) with respect to the overall rates of beta-oxidation, ketogenesis and tricarboxylic acid cycle activity were measured in hepatocytes isolated from rats in different metabolic states (fed, 24 h-starved, starved-refed and starved/insulin-treated). These conditions were chosen because there is controversy as to whether, when significant control ceases to be exerted by CPT I over the rate of fatty oxidation [Moir and Zammit (1994) Trends Biochem. Sci. 19, 313-317], this is transferred to one or more steps proximal to acylcarnitine synthesis (e.g. decreased delivery of fatty acids to the liver) or to the reaction catalysed by mitochondrial 3-hydroxy-3-methyl-glutaryl-CoA synthase [Hegardt (1995) Biochem. Soc. Trans. 23, 486-490]. Therefore isolated hepatocytes were used in the present study to exclude the involvement of changes in the rate of delivery of non-esterified fatty acids (NEFA) to the liver, such as occur in vivo, and to ascertain whether, under conditions of constant supply of NEFA, CPT I retains control over the relevant fluxes of fatty acid oxidation to ketones and carbon dioxide, or whether control is transferred to another (intrahepatocytic) site. The results clearly show that the Flux Control Coefficients of CPT I with respect to overall beta-oxidation and ketogenesis are very high under all conditions investigated, indicating that control is not lost to another intrahepatic site during the metabolic transitions studied. The control of CPT I over tricarboxylic acid cycle activity was always very low. The significance of these findings for the integration of fatty acid and carbohydrate metabolism in the liver is discussed. PMID:8760364

  15. Drug Discovery Opportunities and Challenges at G Protein Coupled Receptors for Long Chain Free Fatty Acids

    PubMed Central

    Holliday, Nicholas D.; Watson, Sarah-Jane; Brown, Alastair J. H.

    2011-01-01

    Discovery of G protein coupled receptors for long chain free fatty acids (FFAs), FFA1 (GPR40) and GPR120, has expanded our understanding of these nutrients as signaling molecules. These receptors have emerged as important sensors for FFA levels in the circulation or the gut lumen, based on evidence from in vitro and rodent models, and an increasing number of human studies. Here we consider their promise as therapeutic targets for metabolic disease, including type 2 diabetes and obesity. FFA1 directly mediates acute FFA-induced glucose-stimulated insulin secretion in pancreatic beta-cells, while GPR120 and FFA1 trigger release of incretins from intestinal endocrine cells, and so indirectly enhance insulin secretion and promote satiety. GPR120 signaling in adipocytes and macrophages also results in insulin sensitizing and beneficial anti-inflammatory effects. Drug discovery has focused on agonists to replicate acute benefits of FFA receptor signaling, with promising early results for FFA1 agonists in man. Controversy surrounding chronic effects of FFA1 on beta-cells illustrates that long term benefits of antagonists also need exploring. It has proved challenging to generate highly selective potent ligands for FFA1 or GPR120 subtypes, given that both receptors have hydrophobic orthosteric binding sites, which are not completely defined and have modest ligand affinity. Structure activity relationships are also reliant on functional read outs, in the absence of robust binding assays to provide direct affinity estimates. Nevertheless synthetic ligands have already helped dissect specific contributions of FFA1 and GPR120 signaling from the many possible cellular effects of FFAs. Approaches including use of fluorescent ligand binding assays, and targeting allosteric receptor sites, may improve further pre-clinical ligand development at these receptors, to exploit their unique potential to target multiple facets of diabetes. PMID:22649399

  16. Boronic acid flux synthesis and crystal growth of uranium and neptunium boronates and borates: a low-temperature route to the first neptunium(V) borate.

    PubMed

    Wang, Shuao; Alekseev, Evgeny V; Miller, Hannah M; Depmeier, Wulf; Albrecht-Schmitt, Thomas E

    2010-11-01

    Molten methylboronic acid has been used as a reactive flux to prepare the first neptunium(V) borate, NpO(2)[B(3)O(4)(OH)(2)] (NpBO-1), and the first actinide boronate, UO(2)(CH(3)BO(2))(H(2)O) (UCBO-1). NpBO-1 contains cation-cation interactions between the neptunyl units. In contrast, the presence of the methyl groups in the uranyl boronate leads to a one-dimensional structure. PMID:20919728

  17. Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells

    PubMed Central

    Wang, Yizhou; Blatt, Michael R.

    2011-01-01

    Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (malate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (ICl) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect ICl, but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of ICl by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with ICl through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes. PMID:21745184

  18. Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells.

    PubMed

    Wang, Yizhou; Blatt, Michael R

    2011-10-01

    Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (malate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (I(Cl)) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect I(Cl), but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of ICl by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with I(Cl) through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes. PMID:21745184

  19. Combined Flux Chamber and Genomics Approach Links Nitrous Acid Emissions to Ammonia Oxidizing Bacteria and Archaea in Urban and Agricultural Soil.

    PubMed

    Scharko, Nicole K; Schütte, Ursel M E; Berke, Andrew E; Banina, Lauren; Peel, Hannah R; Donaldson, Melissa A; Hemmerich, Chris; White, Jeffrey R; Raff, Jonathan D

    2015-12-01

    Nitrous acid (HONO) is a photochemical source of hydroxyl radical and nitric oxide in the atmosphere that stems from abiotic and biogenic processes, including the activity of ammonia-oxidizing soil microbes. HONO fluxes were measured from agricultural and urban soil in mesocosm studies aimed at characterizing biogenic sources and linking them to indigenous microbial consortia. Fluxes of HONO from agricultural and urban soil were suppressed by addition of a nitrification inhibitor and enhanced by amendment with ammonium (NH4(+)), with peaks at 19 and 8 ng m(-2) s(-1), respectively. In addition, both agricultural and urban soils were observed to convert (15)NH4(+) to HO(15)NO. Genomic surveys of soil samples revealed that 1.5-6% of total expressed 16S rRNA sequences detected belonged to known ammonia oxidizing bacteria and archaea. Peak fluxes of HONO were directly related to the abundance of ammonia-oxidizer sequences, which in turn depended on soil pH. Peak HONO fluxes under fertilized conditions are comparable in magnitude to fluxes reported during field campaigns. The results suggest that biogenic HONO emissions will be important in soil environments that exhibit high nitrification rates (e.g., agricultural soil) although the widespread occurrence of ammonia oxidizers implies that biogenic HONO emissions are also possible in the urban and remote environment. PMID:26248160

  20. Effect of Boric Acid Flux and Drying Control Chemical Additive on the Characteristics of Y2O3:Eu Phosphor Particles Prepared by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Koo, Hye Young; Ju, Seo Hee; Hong, Seung Kwon; Jung, Dae Soo; Kang, Yun Chan; Jung, Kyeong Youl

    2006-12-01

    Y2O3:Eu phosphor particles with a spherical shape, a fine size, and high brightness under vacuum ultraviolet (VUV) illumination were prepared by spray pyrolysis. The polymeric precursors were needed to modify the spray solution to prepare spherical particles. The use of only flux with the polymeric precursors did not produce dense and spherical Y2O3:Eu particles; that is, the produced particles were very porous. The addition of both a drying control chemical additive (DCCA) and boric acid to a spray solution containing polymeric precursors was found to produce Y2O3:Eu phosphor particles with a dense structure while maintaining the spherical morphology. According to X-ray diffraction (XRD) analysis, the DCCA induced an enhancement of crystallinity. The use of boric acid flux improved the photoluminescence (PL) intensity under VUV illumination. In addition, the use of both boric acid flux and a DCCA with polymeric precursors further improved the PL intensity owing to the enhancement of the morphology and the crystallinity.

  1. Fatty acid fouling of forward osmosis membrane: Effects of pH, calcium, membrane orientation, initial permeate flux and foulant composition.

    PubMed

    Zhao, Pin; Gao, Baoyu; Yue, Qinyan; Liu, Pan; Shon, Ho Kyong

    2016-08-01

    Octanoic acid (OA) was selected to represent fatty acids in effluent organic matter (EOM). The effects of feed solution (FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis (FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5hr at unadjusted pH3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated pH of 9.00. Moreover, except at the initial stage, the sudden decline of water flux (meaning the occurrence of severe membrane fouling) occurred in two conditions: 1. 0.5mmol/L Ca(2+), active layer facing draw solution (AL-DS) and 1.5mol/L NaCl (DS); 2. No Ca(2+), active layer-facing FS (AL-FS) and 4mol/L NaCl (DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin (BSA) was selected as a co-foulant. The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at pH3.56, and larger than the two values at pH9.00. This manifested that, at pH3.56, BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at pH9.00, the mutual effects of OA and BSA eased the membrane fouling. PMID:27521936

  2. Regulation of metabolic flux in Lactobacillus casei for lactic acid production by overexpressed ldhL gene with two-stage oxygen supply strategy.

    PubMed

    Ge, Xiang-Yang; Xu, Yan; Chen, Xiang; Zhang, Long-Yun

    2015-01-01

    This study describes a novel strategy to regulate the metabolic flux for lactic acid production in Lactobacillus casei. The ldhL gene encoding L-lactate dehydrogenase (L-LDH) was overexpressed in L. casei, and a two-stage oxygen supply strategy (TOS) that maintained a medium oxygen supply level during the early fermentation phase, and a low oxygen supply level in the later phase was carried out. As a consequence, a maximum L-LDH activity of 95.6 U/ml was obtained in the recombinant strain, which was over 4-fold higher than that of the initial strain. Under the TOS for L. casei (pMG-ldhL), the maximum lactic acid concentration of 159.6 g/l was obtained in 36 h, corresponding to a 62.8% increase. The results presented here provide a novel way to regulate the metabolic flux of L. casei for lactic acid production in different fermentation stages, which is available to enhance organic acid production in other strains. PMID:25179900

  3. Elevated free fatty acid uptake via CD36 promotes epithelial-mesenchymal transition in hepatocellular carcinoma

    PubMed Central

    Nath, Aritro; Li, Irene; Roberts, Lewis R.; Chan, Christina

    2015-01-01

    Hepatocellular carcinoma (HCC) is the second-leading cause of cancer-related death worldwide, and the factors influencing HCC progression are poorly understood. Here we reveal that HCC progression via induction of epithelial-mesenchymal transition (EMT) is closely associated with the expression of CD36/fatty acid translocase and elevated free fatty acid (FFA) levels. Although obesity is manifested as elevated FFA levels, the degree of EMT was not associated with the body mass index of the patients, highlighting the specific roles of CD36 and FFA uptake. Treatment of human liver cancer cell lines with FFAs exacerbated the EMT phenotype, whereas chemical inhibition of CD36 mitigated these effects. Furthermore, the Wnt and TGF-β signaling pathways were activated upon FFA treatment, potentially acting as upstream activators of the EMT program. These results provide the first direct evidence associating CD36 and elevated FFAs with HCC progression. PMID:26424075

  4. Ferric sulphate catalysed esterification of free fatty acids in waste cooking oil.

    PubMed

    Gan, Suyin; Ng, Hoon Kiat; Ooi, Chun Weng; Motala, Nafisa Osman; Ismail, Mohd Anas Farhan

    2010-10-01

    In this work, the esterification of free fatty acids (FFA) in waste cooking oil catalysed by ferric sulphate was studied as a pre-treatment step for biodiesel production. The effects of reaction time, methanol to oil ratio, catalyst concentration and temperature on the conversion of FFA were investigated on a laboratory scale. The results showed that the conversion of FFA reached equilibrium after an hour, and was positively dependent on the methanol to oil molar ratio and temperature. An optimum catalyst concentration of 2 wt.% gave maximum FFA conversion of 59.2%. For catalyst loadings of 2 wt.% and below, this catalysed esterification was proposed to follow a pseudo-homogeneous pathway akin to mineral acid-catalysed esterification, driven by the H(+) ions produced through the hydrolysis of metal complex [Fe(H(2)O)(6)](3+) (aq). PMID:20435468

  5. Transport of free and peptide-bound glycated amino acids: synthesis, transepithelial flux at Caco-2 cell monolayers, and interaction with apical membrane transport proteins.

    PubMed

    Hellwig, Michael; Geissler, Stefanie; Matthes, René; Peto, Anett; Silow, Christoph; Brandsch, Matthias; Henle, Thomas

    2011-05-16

    In glycation reactions, the side chains of protein-bound nucleophilic amino acids such as lysine and arginine are post-translationally modified to a variety of derivatives also known as Maillard reaction products (MRPs). Considerable amounts of MRPs are taken up in food. Here we have studied the interactions of free and dipeptide-bound MRPs with intestinal transport systems. Free and dipeptide-bound derivatives of N(6)-(1-fructosyl)lysine (FL), N(6)-(carboxymethyl)lysine (CML), N(6)-(1-carboxyethyl)lysine (CEL), formyline, argpyrimidine, and methylglyoxal-derived hydroimidazolone 1 (MG-H1) were synthesized. The inhibition of L-[(3)H]lysine and [(14) C]glycylsarcosine uptakes was measured in Caco-2 cells which express the H(+)/peptide transporter PEPT1 and lysine transport system(s). Glycated amino acids always displayed lower affinities than their unmodified analogues towards the L-[(3)H]lysine transporter(s). In contrast, all glycated dipeptides except Ala-FL were medium- to high-affinity inhibitors of [(14)C]Gly-Sar uptake. The transepithelial flux of the derivatives across Caco-2 cell monolayers was determined. Free amino acids and intact peptides derived from CML and CEL were translocated to very small extents. Application of peptide-bound MRPs, however, led to elevation (up to 80-fold) of the net flux and intracellular accumulation of glycated amino acids, which were hydrolyzed from the dipeptides inside the cells. We conclude 1) that free MRPs are not substrates for the intestinal lysine transporter(s), and 2) that dietary MRPs are absorbed into intestinal cells in the form of dipeptides, most likely by the peptide transporter PEPT1. After hydrolysis, hydrophobic glycated amino acids such as pyrraline, formyline, maltosine, and argpyrimidine undergo basolateral efflux, most likely by simple diffusion down their concentration gradients. PMID:21538757

  6. pH gradients and a micro-pore filter at the luminal surface affect fluxes of propionic acid across guinea pig large intestine.

    PubMed

    Busche, Roger; von Engelhardt, Wolfgang

    2007-10-01

    A neutral pH microclimate had been shown at the luminal surface of the large intestine. The aim was to estimate to what extent fluxes of propionic acid/propionate are affected by changes of the luminal pH when this microclimate is present, largely reduced or absent. Fluxes of propionic acid/propionate (J(Pr)) across epithelia from the caecum, the proximal and the distal colon of guinea pigs were measured in Ussing chambers with and without a filter at the luminal surface. With bicarbonate and with a neutral or an acid pH of mucosal solutions (pH 7.4 or 6.4), mucosal-to-serosal fluxes (J(ms)(Pr) ) were 1.5 to 1.9-fold higher at the lower pH, in bicarbonate-free solutions and carbonic anhydrase (CA) inhibition 2.1 to 2.6-fold. With a filter at the mucosal surface and with bicarbonate containing solutions, J (ms) (Pr) was not or only little elevated at the lower pH. Without bicarbonate J(ms)(Pr) was clearly higher. We conclude that the higher J(ms)(Pr) after luminal acidification is due to vigorous mixing in Ussing chambers resulting in a markedly reduced unstirred layer. Therefore, an effective pH microclimate at the epithelial surface is missing. J(ms)(Pr) is not or is little affected by lowering of pH because in the presence of bicarbonate the filter maintains the pH microclimate. However, in bicarbonate-free solutions J(ms)(Pr) was higher at pH 6.4 because a pH microclimate does not develop. Findings confirm that 30-60% of J(ms)(Pr) results from non-ionic diffusion. PMID:17639416

  7. Phenylboronic Acid Solid Phase Extraction Cleanup and Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Florfenicol Amine in Fish Muscles.

    PubMed

    Sin, Della Wai-Mei; Ho, Clare; Wong, Yiu-Tung

    2015-01-01

    Florfenicol (FFC) residues in foods are regulated as the sum of florfenicol and its metabolites measured as florfenicol amine (FFA). An isotope dilution LC-MS/MS method utilizing phenylboronic acid (PBA) SPE cleanup is established for the accurate determination of FFA in fish muscles (i.e., salmon and tilapia) after acid catalyzed hydrolysis. Comparisons of the PBA SPE cleanup procedure with other cleanup procedures such as mixed-mode cationic (MCX) SPE and solid supported liquid-liquid extraction were performed. Quantification of FFA in fish muscles was accomplished by using matrix-matched calibration with FFA-D3 as the internal standard. The method was validated with FFA fortified fish muscles at three different levels (50, 100, and 200 μg/kg). Conversion of FFC to FFA by acid catalyzed hydrolysis was evaluated and found to be ≥88%. The recoveries of FFA in fish muscles at the three fortification levels ranged from 89 to 106%, and RSDs were ≤9% in all cases. The LOD values in salmon and tilapia muscles were 0.13 and 1.64 μg/kg, respectively. The LOQ values in salmon and tilapia muscles were 0.29 and 4.13 μg/kg, respectively. This method is suitable for the application in routine control of FFC in fishes according to its residue definition. PMID:26025252

  8. Boronic Acid Flux Synthesis and Crystal Growth of Uranium and Neptunium Boronates and Borates: A Low Temperature Route to the First Neptunium(V) Borate

    SciTech Connect

    Wang, Shuao; Alekseev, Evgeny V.; Miller, Hannah M.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.

    2010-10-04

    Molten methylboronic acid has been used as a reactive flux to prepare the first neptunium(V) borate, NpO2[B3O4(OH)2] (NpBO-1), and the first actinide boronate, UO2(CH3BO2)(H2O) (UCBO-1). NpBO-1 contains cation-cation interactions between the neptunyl units. In contrast, the presence of the methyl groups in the uranyl boronate leads to a one-dimensional structure.

  9. Discovery of a potent and selective free fatty acid receptor 1 agonist with low lipophilicity and high oral bioavailability.

    PubMed

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian; Grundmann, Manuel; Schmidt, Johannes; Hansen, Steffen V F; Hudson, Brian D; Zaibi, Mohamed; Markussen, Stine B; Hagesaether, Ellen; Milligan, Graeme; Cawthorne, Michael A; Kostenis, Evi; Kassack, Matthias U; Ulven, Trond

    2013-02-14

    The free fatty acid receptor 1 (FFA1, also known as GPR40) mediates enhancement of glucose-stimulated insulin secretion and is emerging as a new target for the treatment of type 2 diabetes. Several FFA1 agonists are known, but the majority of these suffer from high lipophilicity. We have previously reported the FFA1 agonist 3 (TUG-424). We here describe the continued structure-activity exploration and optimization of this compound series, leading to the discovery of the more potent agonist 40, a compound with low lipophilicity, excellent in vitro metabolic stability and permeability, complete oral bioavailability, and appreciable efficacy on glucose tolerance in mice. PMID:23294321

  10. A Self-defeating Anabolic Program Leads to β-Cell Apoptosis in Endoplasmic Reticulum Stress-induced Diabetes via Regulation of Amino Acid Flux*

    PubMed Central

    Krokowski, Dawid; Han, Jaeseok; Saikia, Mridusmita; Majumder, Mithu; Yuan, Celvie L.; Guan, Bo-Jhih; Bevilacqua, Elena; Bussolati, Ovidio; Bröer, Stefan; Arvan, Peter; Tchórzewski, Marek; Snider, Martin D.; Puchowicz, Michelle; Croniger, Colleen M.; Kimball, Scot R.; Pan, Tao; Koromilas, Antonis E.; Kaufman, Randal J.; Hatzoglou, Maria

    2013-01-01

    Endoplasmic reticulum (ER) stress-induced responses are associated with the loss of insulin-producing β-cells in type 2 diabetes mellitus. β-Cell survival during ER stress is believed to depend on decreased protein synthesis rates that are mediated via phosphorylation of the translation initiation factor eIF2α. It is reported here that chronic ER stress correlated with increased islet protein synthesis and apoptosis in β-cells in vivo. Paradoxically, chronic ER stress in β-cells induced an anabolic transcription program to overcome translational repression by eIF2α phosphorylation. This program included expression of amino acid transporter and aminoacyl-tRNA synthetase genes downstream of the stress-induced ATF4-mediated transcription program. The anabolic response was associated with increased amino acid flux and charging of tRNAs for branched chain and aromatic amino acids (e.g. leucine and tryptophan), the levels of which are early serum indicators of diabetes. We conclude that regulation of amino acid transport in β-cells during ER stress involves responses leading to increased protein synthesis, which can be protective during acute stress but can lead to apoptosis during chronic stress. These studies suggest that the increased expression of amino acid transporters in islets can serve as early diagnostic biomarkers for the development of diabetes. PMID:23645676

  11. Increased physical activity decreases hepatic free fatty acid uptake: a study in human monozygotic twins.

    PubMed

    Hannukainen, Jarna C; Nuutila, Pirjo; Borra, Ronald; Ronald, Borra; Kaprio, Jaakko; Kujala, Urho M; Janatuinen, Tuula; Heinonen, Olli J; Kapanen, Jukka; Viljanen, Tapio; Haaparanta, Merja; Rönnemaa, Tapani; Parkkola, Riitta; Knuuti, Juhani; Kalliokoski, Kari K

    2007-01-01

    Exercise is considered to be beneficial for free fatty acid (FFA) metabolism, although reports of the effects of increased physical activity on FFA uptake and oxidation in different tissues in vivo in humans have been inconsistent. To investigate the heredity-independent effects of physical activity and fitness on FFA uptake in skeletal muscle, the myocardium, and liver we used positron emission tomography (PET) in nine healthy young male monozygotic twin pairs discordant for physical activity and fitness. The cotwins with higher physical activity constituting the more active group had a similar body mass index but less body fat and 18 +/- 10% higher (P < 0.001) compared to the less active brothers with lower physical activity. Low-intensity knee-extension exercise increased skeletal muscle FFA and oxygen uptake six to 10 times compared to resting values but no differences were observed between the groups at rest or during exercise. At rest the more active group had lower hepatic FFA uptake compared to the less active group (5.5 +/- 4.3 versus 9.0 +/- 6.1 micromol (100 ml)(-1) min(-1), P = 0.04). Hepatic FFA uptake associated significantly with body fat percentage (P = 0.05). Myocardial FFA uptake was similar between the groups. In conclusion, in the absence of the confounding effects of genetic factors, moderately increased physical activity and aerobic fitness decrease body adiposity even in normal-weighted healthy young adult men. Further, increased physical activity together with decreased intra-abdominal adiposity seems to decrease hepatic FFA uptake but has no effects on skeletal muscle or myocardial FFA uptake. PMID:17053033

  12. Loss of Free Fatty Acid Receptor 2 leads to impaired islet mass and beta cell survival

    PubMed Central

    Villa, Stephanie R.; Priyadarshini, Medha; Fuller, Miles H.; Bhardwaj, Tanya; Brodsky, Michael R.; Angueira, Anthony R.; Mosser, Rockann E.; Carboneau, Bethany A.; Tersey, Sarah A.; Mancebo, Helena; Gilchrist, Annette; Mirmira, Raghavendra G.; Gannon, Maureen; Layden, Brian T.

    2016-01-01

    The regulation of pancreatic β cell mass is a critical factor to help maintain normoglycemia during insulin resistance. Nutrient-sensing G protein-coupled receptors (GPCR) contribute to aspects of β cell function, including regulation of β cell mass. Nutrients such as free fatty acids (FFAs) contribute to precise regulation of β cell mass by signaling through cognate GPCRs, and considerable evidence suggests that circulating FFAs promote β cell expansion by direct and indirect mechanisms. Free Fatty Acid Receptor 2 (FFA2) is a β cell-expressed GPCR that is activated by short chain fatty acids, particularly acetate. Recent studies of FFA2 suggest that it may act as a regulator of β cell function. Here, we set out to explore what role FFA2 may play in regulation of β cell mass. Interestingly, Ffar2−/− mice exhibit diminished β cell mass at birth and throughout adulthood, and increased β cell death at adolescent time points, suggesting a role for FFA2 in establishment and maintenance of β cell mass. Additionally, activation of FFA2 with Gαq/11-biased agonists substantially increased β cell proliferation in in vitro and ex vivo proliferation assays. Collectively, these data suggest that FFA2 may be a novel therapeutic target to stimulate β cell growth and proliferation. PMID:27324831

  13. Loss of Free Fatty Acid Receptor 2 leads to impaired islet mass and beta cell survival.

    PubMed

    Villa, Stephanie R; Priyadarshini, Medha; Fuller, Miles H; Bhardwaj, Tanya; Brodsky, Michael R; Angueira, Anthony R; Mosser, Rockann E; Carboneau, Bethany A; Tersey, Sarah A; Mancebo, Helena; Gilchrist, Annette; Mirmira, Raghavendra G; Gannon, Maureen; Layden, Brian T

    2016-01-01

    The regulation of pancreatic β cell mass is a critical factor to help maintain normoglycemia during insulin resistance. Nutrient-sensing G protein-coupled receptors (GPCR) contribute to aspects of β cell function, including regulation of β cell mass. Nutrients such as free fatty acids (FFAs) contribute to precise regulation of β cell mass by signaling through cognate GPCRs, and considerable evidence suggests that circulating FFAs promote β cell expansion by direct and indirect mechanisms. Free Fatty Acid Receptor 2 (FFA2) is a β cell-expressed GPCR that is activated by short chain fatty acids, particularly acetate. Recent studies of FFA2 suggest that it may act as a regulator of β cell function. Here, we set out to explore what role FFA2 may play in regulation of β cell mass. Interestingly, Ffar2(-/-) mice exhibit diminished β cell mass at birth and throughout adulthood, and increased β cell death at adolescent time points, suggesting a role for FFA2 in establishment and maintenance of β cell mass. Additionally, activation of FFA2 with Gαq/11-biased agonists substantially increased β cell proliferation in in vitro and ex vivo proliferation assays. Collectively, these data suggest that FFA2 may be a novel therapeutic target to stimulate β cell growth and proliferation. PMID:27324831

  14. Free fatty acid levels in fluid of dominant follicles at the preferred insemination time in dairy cows are not affected by early postpartum fatty acid stress.

    PubMed

    Aardema, Hilde; Gadella, Bart M; van de Lest, Chris H A; Brouwers, Jos F H M; Stout, Tom A E; Roelen, Bernard A J; Vos, Peter L A M

    2015-04-01

    The fertility of high-yielding dairy cows has declined during the last 3 decades, in association with a more profound negative energy balance (NEB) during the early weeks postpartum. One feature of this NEB is a marked elevation in circulating free fatty acid (FFA) concentrations. During the early postpartum period (≤ d 42), circulatory FFA levels were measured weekly, and progesterone concentrations and the diameter of the dominant follicles were determined thrice weekly. Retrospectively, cows that ovulated within 35 d postpartum were grouped as "normal ovulating" cows (n = 5), and the others were grouped as "delayed ovulating" cows (n = 5). In both groups, high total FFA levels (>500 µM) were evident immediately postpartum. Interestingly, cows with delayed ovulation had higher plasma FFA concentrations in the first weeks postpartum compared with normal ovulating cows. In both cow groups, FFA decreased to control levels of non-NEB cows within 3 wk postpartum. The FFA compositions and concentrations in fluids from the dominant follicles of postpartum cows were not different between the normal and delayed ovulating cows when measured at potential insemination points: d 55, 80, and 105 postpartum. Interestingly, the concentration of monounsaturated oleic acid was higher and that of saturated stearic acid lower in follicular fluids of both groups compared with that in blood. The level of FFA in follicular fluid was correlated with the ratio of 17β-estradiol (E2) to progesterone (P4) in follicular fluid, with a relatively high level of unsaturated FFA in follicles with a low E2:P4 ratio. Taken together, these results indicate that a more severe NEB early postpartum is related to a delay in the first postpartum ovulation and does not affect FFA composition in follicular fluid at the preferred insemination time. The high FFA level in dominant follicles with a low E2:P4 ratio may be due to a different FFA metabolism in these follicles. The diagnostic value of this

  15. Using poly(3-aminophenylboronic acid) thin film with binding-induced ion flux blocking for amperometric detection of hemoglobin A1c.

    PubMed

    Wang, Jen-Yuan; Chou, Tse-Chuan; Chen, Lin-Chi; Ho, Kuo-Chuan

    2015-01-15

    This study reports a novel enzyme-free, label-free amperometric method for direct detection of hemoglobin A1c (Hb(A1c)), a potent biomarker for diabetes diagnosis and prognosis. The method relies on an electrode modified with poly(3-aminophenylboronic acid) (PAPBA) nanoparticles (20-50 nm) and a sensing scheme named "binding-induced ion flux blocking." The PAPBA nanoparticles were characterized by FT-IR, XPS, TEM, and SEM. Being a polyaniline derivative, PAPBA showed an ion-dependent redox behavior, in which insertion or extraction of ions into or out of PABPA occurred for charge balance during the electron transfer process. The polymer allowed Hb(A1c) selectively bound to its surface via forming the cis-diol linkage between the boronic acid and sugar moieties. Voltammetric analyses showed that Hb(A1c) binding decreased the redox current of PAPBA; however, the binding did not alter the redox potentials and the apparent diffusivities of ions. This suggests that the redox current of PAPBA decreased due to an Hb(A1c) binding-induced ion flux blocking mechanism, which was then verified and characterized through an in situ electrochemical quartz crystal microbalance (EQCM) study. Assay with Hb(A1c) by differential pulse voltammetry (DPV) indicates that the peak current of a PAPBA electrode has a linear dependence on the logarithm of Hb(A1c) concentration ranging from 0.975 to 156 μM. The Hb(A1c) assay also showed high selectivity against ascorbic acid, dopamine, uric acid, glucose and bovine serum albumin. This study has demonstrated a new method for developing an electrochemical Hb(A1c) biosensor and can be extended to other label-free, indicator-free protein biosensors based on a similar redox polymer electrode. PMID:25113050

  16. Implementation plan for liquid low-level radioactive waste systems under the FFA for Fiscal years 1996 and 1997 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    SciTech Connect

    1996-10-01

    The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requires a Federal Facility Agreement (FFA) for federal facilities placed on the National Priorities List. The Oak Ridge Reservation was placed on that list on December 21, 1989, and the agreement was signed in November 1991 by the Department of Energy Oak Ridge Operations Office (DOE-ORO), the U.S. Environmental Protection Agency (EPA)-Region IV, and the Tennessee Department of Environment and Conservation (TDEC). The effective date of the FFA was January 1, 1992. Section IX and Appendix F of the agreement impose design and operating requirements on the Oak Ridge National Laboratory (ORNL) liquid low-level radioactive waste (LLLW) tank systems and identify several plans, schedules, and assessments that must be submitted to EPA/TDEC for review of approval. The issue of ES/ER-17&D1 Federal Facility Agreement Plans and Schedules for Liquid Low-Level Radioactive Waste Tank Systems at Oak Ridge National Laboratory, Oak Ridge, Tennessee in March 1992 transmitted to EPA/TDEC those plans and schedules that were required within 60 to 90 days of the FFA effective date. This document updates the plans, schedules, and strategy for achieving compliance with the FFA as presented in ES/ER-17&D I and summarizes the progress that has been made to date. This document supersedes all updates of ES/ER- 17&D 1. Chapter 1 describes the history and operation of the ORNL LLLW System and the objectives of the FFA. Chapters 2 through 5 contain the updated plans and schedules for meeting FFA requirements. This document will continue to be periodically reassessed and refined to reflect newly developed information and progress.

  17. Determination of plasma-free fatty acid kinetics with tracers: Methodologic considerations

    SciTech Connect

    Miles, J.M.; Jensen, M.D. )

    1991-05-01

    Plasma-free fatty acids (FFA) are an important source of energy for a variety of tissues. Recently, there has been an increased interest in the measurement of FFA kinetics in vivo, using radiolabeled or stable isotopic tracers. Standard techniques for measurement of FFA-specific activity are relatively imprecise and have limited sensitivity. The authors have developed a method for determination of the concentration and specific activity of individual plasma FFA that is precise (coefficient of variation less than 2%) and sensitive (detection limit in the high femptomolar to low picomolar range). Using this method, one can measure the kinetics of three or more long-chain fatty acids simultaneously. Its sensitivity is a particular advantage if one wishes to measure low rates of FFA turnover such as are encountered during hyperinsulinemia. It has been suggested that, for optimal accuracy in the determination of substrate kinetics, the tracer should be administered in the left ventricle and mixed venous blood samples should be obtained from the right heart. They have conducted experiments in dogs which demonstrate that peripheral tracer infusion and more conventional arterial (or arterialized venous) sampling actually provide more accurate estimates of FFA turnover; this is fortunate, since intracardiac infusion and sampling are not practical for human studies. 39 references.

  18. Associations between free fatty acids, cumulus oocyte complex morphology and ovarian function during in vitro fertilization

    PubMed Central

    Jungheim, Emily S.; Macones, George A.; Odem, Randall R.; Patterson, Bruce W.; Lanzendorf, Susan E.; Ratts, Valerie S.; Moley, Kelle H.

    2011-01-01

    Objective To determine if follicular free fatty acid (FFA) levels are associated with cumulus oocyte complex morphology Design Prospective cohort study Setting University in vitro fertilization (IVF) practice Patients 102 women undergoing IVF Interventions Measurement of FFAs in serum and ovarian follicular fluid Main Outcome Measures Total and specific follicular and serum FFA levels, correlations between follicular and serum FFAs, and associations between follicular FFA levels and markers of oocyte quality including cumulus oocyte complex (COC) morphology Results Predominant follicular fluid and serum FFAs were oleic, palmitic, linoleic and stearic acids. Correlations between follicular and serum FFA concentrations were weak (r=0.252, 0.288, 0.236, 0.309 respectively for specific FFAs; r=0.212 for total FFAs). A receiver operator characteristic curve determined total follicular FFAs ≥ 0.232 µmol/ml distinguished women with lower versus higher percentage COCs with favorable morphology. Women with elevated follicular FFAs (n=31) were more likely to have COCs with poor morphology than others (n=71) (OR 3.3, 95% CI:1.2–9.2). This relationship held after adjusting for potential confounders including age, BMI, endometriosis and amount of gonadotropin administered (β=1.2; OR 3.4, 95% CI:1.1–10.4). Conclusions Elevated follicular FFA levels are associated with poor COC morphology. Further work is needed to determine what factors influence follicular FFA levels and if these factors impact fertility. PMID:21353671

  19. Microbial Oxidation of Fe2+ and Pyrite Exposed to Flux of Micromolar H2O2 in Acidic Media

    NASA Astrophysics Data System (ADS)

    Ma, Yingqun; Lin, Chuxia

    2013-06-01

    At an initial pH of 2, while abiotic oxidation of aqueous Fe2+ was enhanced by a flux of H2O2 at micromolar concentrations, bio-oxidation of aqueous Fe2+ could be impeded due to oxidative stress/damage in Acidithiobacillus ferrooxidans caused by Fenton reaction-derived hydroxyl radical, particularly when the molar ratio of Fe2+ to H2O2 was low. When pyrite cubes were intermittently exposed to fluxes of micromolar H2O2, the reduced Fe2+-Fe3+ conversion rate in the solution (due to reduced microbial activity) weakened the Fe3+-catalyzed oxidation of cubic pyrite and added to relative importance of H2O2-driven oxidation in the corrosion of mineral surfaces for the treatments with high H2O2 doses. This had effects on reducing the build-up of a passivating coating layer on the mineral surfaces. Cell attachment to the mineral surfaces was only observed at the later stage of the experiment after the solutions became less favorable for the growth of planktonic bacteria.

  20. Microbial Oxidation of Fe2+ and Pyrite Exposed to Flux of Micromolar H2O2 in Acidic Media

    PubMed Central

    Ma, Yingqun; Lin, Chuxia

    2013-01-01

    At an initial pH of 2, while abiotic oxidation of aqueous Fe2+ was enhanced by a flux of H2O2 at micromolar concentrations, bio-oxidation of aqueous Fe2+ could be impeded due to oxidative stress/damage in Acidithiobacillus ferrooxidans caused by Fenton reaction-derived hydroxyl radical, particularly when the molar ratio of Fe2+ to H2O2 was low. When pyrite cubes were intermittently exposed to fluxes of micromolar H2O2, the reduced Fe2+-Fe3+ conversion rate in the solution (due to reduced microbial activity) weakened the Fe3+-catalyzed oxidation of cubic pyrite and added to relative importance of H2O2-driven oxidation in the corrosion of mineral surfaces for the treatments with high H2O2 doses. This had effects on reducing the build-up of a passivating coating layer on the mineral surfaces. Cell attachment to the mineral surfaces was only observed at the later stage of the experiment after the solutions became less favorable for the growth of planktonic bacteria. PMID:23760258

  1. Metabolic Flux Between Unsaturated and Saturated Fatty Acids is Controlled by the FabA:FabB Ratio in the Fully Reconstituted Fatty Acid Biosynthetic Pathway of E. coli#

    PubMed Central

    Xiao, Xirui; Yu, Xingye; Khosla, Chaitan

    2013-01-01

    The entire fatty acid biosynthetic pathway from Escherichia coli, starting from the acetyl-CoA carboxylase, has been reconstituted in vitro from fourteen purified protein components. Radiotracer analysis verified stoichiometric conversion of acetyl-CoA and NAD(P)H into the free fatty acid product, allowing implementation of a facile spectrophotometric assay for kinetic analysis of this multi-enzyme system. At steady state, a maximum turnover rate of 0.5 s−1 was achieved. Under optimal turnover conditions, the predominant products were C16 and C18 saturated as well as monounsaturated fatty acids. The reconstituted system allowed us to quantitatively interrogate the factors that influence metabolic flux toward unsaturated versus saturated fatty acids. In particular, the concentrations of the dehydratase FabA and the β-ketoacyl synthase FabB were found to be crucial for controlling this property. By altering these variables, the percentage of unsaturated fatty acid produced could be adjusted between 10 and 50% without significantly affecting the maximum turnover rate of the pathway. Our reconstituted system provides a powerful tool to understand and engineer rate-limiting and regulatory steps in this complex and practically significant metabolic pathway. PMID:24147979

  2. Benthic metal fluxes and sediment diagenesis in a water reservoir affected by acid mine drainage: A laboratory experiment and reactive transport modeling

    NASA Astrophysics Data System (ADS)

    Torres, E.; Ayora, C.; Jiménez-Arias, J. L.; García-Robledo, E.; Papaspyrou, S.; Corzo, A.

    2014-08-01

    Reservoirs are one of the primary water supply sources. Knowledge of the metal fluxes at the water-sediment interfaces of reservoirs is essential for predicting their ecological quality. Redox oscillations in the water column are promoted by stratification; turnover events may significantly alter metal cycling, especially in reservoirs impacted by acid mine drainage (AMD). To study this phenomenon, an experiment was performed under controlled laboratory conditions. Sediment cores from an AMD-affected reservoir were maintained in a tank with reservoir water for approximately two months and subjected to alternating oxic-hypoxic conditions. A detailed metal speciation in solid phases of the sediment was initially performed by sequential extraction, and pore water was analyzed at the end of each redox period. Tank water metals concentrations were systematically monitored throughout the experiment. The experimental results were then used to calibrate a diffusion-reaction model and quantify the reaction rates and sediment-water fluxes. Under oxic conditions, pH, Fe and As concentrations decreased in the tank due to schwertmannite precipitation, whereas the concentrations of Al, Zn, Cu, Ni, and Co increased due to Al(OH)3 and sulfide dissolution. The reverse trends occurred under hypoxic conditions. Under oxic conditions, the fluxes calculated by applying Fick’s first law to experimental concentration gradients contradicted the fluxes expected based on the evolution of the tank water. According to the reactive transport calculations, this discrepancy can be attributed to the coarse resolution of sediment sampling. The one-cm-thick slices failed to capture effectively the notably narrow (1-2 mm) concentration peaks of several elements in the shallow pore water resulting from sulfide and Al(OH)3 dissolution. The diffusion-reaction model, extended to the complete year, computed that between 25% and 50% of the trace metals and less than 10% of the Al that precipitated under

  3. Defense Priming and Jasmonates: A Role for Free Fatty Acids in Insect Elicitor-Induced Long Distance Signaling.

    PubMed

    Li, Ting; Cofer, Tristan; Engelberth, Marie; Engelberth, Jurgen

    2016-01-01

    Green leaf volatiles (GLV) prime plants against insect herbivore attack resulting in stronger and faster signaling by jasmonic acid (JA). In maize this response is specifically linked to insect elicitor (IE)-induced signaling processes, which cause JA accumulation not only around the damage site, but also in distant tissues, presumably through the activation of electrical signals. Here, we present additional data further characterizing these distal signaling events in maize. Also, we describe how exposure to GLV increases free fatty acid (fFA) levels in maize seedlings, but also in other plants, and how increased fFA levels affect IE-induced JA accumulation. Increased fFA, in particular α-linolenic acid (LnA), caused a significant increase in JA accumulation after IE treatment, while JA induced by mechanical wounding (MW) alone was not affected. We also identified treatments that significantly decreased certain fFA level including simulated wind and rain. In such treated plants, IE-induced JA accumulation was significantly reduced when compared to un-moved control plants, while MW-induced JA accumulation was not significantly affected. Since only IE-induced JA accumulation was altered by changes in the fFA composition, we conclude that changing levels of fFA affect primarily IE-induced signaling processes rather than serving as a substrate for JA. PMID:27135225

  4. Defense Priming and Jasmonates: A Role for Free Fatty Acids in Insect Elicitor-Induced Long Distance Signaling

    PubMed Central

    Li, Ting; Cofer, Tristan; Engelberth, Marie; Engelberth, Jurgen

    2016-01-01

    Green leaf volatiles (GLV) prime plants against insect herbivore attack resulting in stronger and faster signaling by jasmonic acid (JA). In maize this response is specifically linked to insect elicitor (IE)-induced signaling processes, which cause JA accumulation not only around the damage site, but also in distant tissues, presumably through the activation of electrical signals. Here, we present additional data further characterizing these distal signaling events in maize. Also, we describe how exposure to GLV increases free fatty acid (fFA) levels in maize seedlings, but also in other plants, and how increased fFA levels affect IE-induced JA accumulation. Increased fFA, in particular α-linolenic acid (LnA), caused a significant increase in JA accumulation after IE treatment, while JA induced by mechanical wounding (MW) alone was not affected. We also identified treatments that significantly decreased certain fFA level including simulated wind and rain. In such treated plants, IE-induced JA accumulation was significantly reduced when compared to un-moved control plants, while MW-induced JA accumulation was not significantly affected. Since only IE-induced JA accumulation was altered by changes in the fFA composition, we conclude that changing levels of fFA affect primarily IE-induced signaling processes rather than serving as a substrate for JA. PMID:27135225

  5. An Internal Evaluation of the National FFA Agricultural Mechanics Career Development Event through Analysis of Individual and Team Scores from 1996-2006

    ERIC Educational Resources Information Center

    Franklin, Edward A.; Armbruster, James

    2012-01-01

    The purpose of this study was to conduct an internal evaluation of the National FFA Agricultural Mechanics Career Development Event (CDE) through analysis of individual and team scores from 1996-2006. Data were analyzed by overall and sub-event areas scores for individual contestants and team event. To facilitate the analysis process scores were…

  6. Perceptions of North Carolina High School Agricultural Educators regarding Students with Special Needs Participating in Supervised Agricultural Experience and FFA Activities

    ERIC Educational Resources Information Center

    Johnson, Lendy; Wilson, Elizabeth; Flowers, Jim; Croom, Barry

    2012-01-01

    The purpose of this study was to examine the perceptions of North Carolina high school agricultural educators toward including students with special needs when implementing Supervised Agricultural Experience and participating in FFA activities. The population was all high school agricultural educators in North Carolina with 12 month employment (N…

  7. Pore-expanded SBA-15 sulfonic acid silicas for biodiesel synthesis.

    PubMed

    Dacquin, J P; Lee, A F; Pirez, C; Wilson, K

    2012-01-01

    Here we present the first application of pore-expanded SBA-15 in heterogeneous catalysis. Pore expansion over the range 6-14 nm confers a striking activity enhancement towards fatty acid methyl ester (FAME) synthesis from triglycerides (TAG), and free fatty acid (FFA), attributed to improved mass transport and acid site accessibility. PMID:22089025

  8. Redirection of Metabolic Flux into Novel Gamma-Aminobutyric Acid Production Pathway by Introduction of Synthetic Scaffolds Strategy in Escherichia Coli.

    PubMed

    Pham, Van Dung; Somasundaram, Sivachandiran; Lee, Seung Hwan; Park, Si Jae; Hong, Soon Ho

    2016-04-01

    In general, gamma-aminobutyric acid (GABA) pathway involves the decarboxylation of glutamate, which is produced from sugar by Corynebacterium fermentation. GABA can be used for the production of pharmaceuticals and functional foods. Due to the increasing demand of GABA, it is essential to create an effective alternative pathway for the GABA production. In this study, Escherichia coli were engineered to produce GABA from glucose via GABA shunt, which consists of succinate dehydrogenase, succinate-semialdehyde dehydrogenase, and GABA aminotransferase. The three enzymes were physically attached to each other through a synthetic scaffold, and the Krebs cycle flux was redirected to the GABA pathway. By introduction of synthetic scaffold, 0.75 g/l of GABA was produced from 10 g/l of glucose at 30 °C and pH 6.5. The inactivation of competing metabolic pathways provided 15.4 % increase in the final GABA concentration. PMID:26667817

  9. Retinoic Acid Induced-Autophagic Flux Inhibits ER-Stress Dependent Apoptosis and Prevents Disruption of Blood-Spinal Cord Barrier after Spinal Cord Injury

    PubMed Central

    Zhou, Yulong; Zhang, Hongyu; Zheng, Binbin; Ye, Libing; Zhu, Sipin; Johnson, Noah R; Wang, Zhouguang; Wei, Xiaojie; Chen, Daqing; Cao, Guodong; Fu, Xiaobing; Li, Xiaokun; Xu, Hua-Zi; Xiao, Jian

    2016-01-01

    Spinal cord injury (SCI) induces the disruption of the blood-spinal cord barrier (BSCB) which leads to infiltration of blood cells, an inflammatory response, and neuronal cell death, resulting spinal cord secondary damage. Retinoic acid (RA) has a neuroprotective effect in both ischemic brain injury and SCI, however the relationship between BSCB disruption and RA in SCI is still unclear. In this study, we demonstrated that autophagy and ER stress are involved in the protective effect of RA on the BSCB. RA attenuated BSCB permeability and decreased the loss of tight junction (TJ) molecules such as P120, β-catenin, Occludin and Claudin5 after injury in vivo as well as in Brain Microvascular Endothelial Cells (BMECs). Moreover, RA administration improved functional recovery in the rat model of SCI. RA inhibited the expression of CHOP and caspase-12 by induction of autophagic flux. However, RA had no significant effect on protein expression of GRP78 and PDI. Furthermore, combining RA with the autophagy inhibitor chloroquine (CQ) partially abolished its protective effect on the BSCB via exacerbated ER stress and subsequent loss of tight junctions. Taken together, the neuroprotective role of RA in recovery from SCI is related to prevention of of BSCB disruption via the activation of autophagic flux and the inhibition of ER stress-induced cell apoptosis. These findings lay the groundwork for future translational studies of RA for CNS diseases, especially those related to BSCB disruption. PMID:26722220

  10. Investigating the Influence of Polymers on Supersaturated Flufenamic Acid Cocrystal Solutions.

    PubMed

    Guo, Minshan; Wang, Ke; Hamill, Noel; Lorimer, Keith; Li, Mingzhong

    2016-09-01

    The development of enabling formulations is a key stage when demonstrating the effectiveness of pharmaceutical cocrystals to maximize the oral bioavailability for poorly water soluble drugs. Inhibition of drug crystallization from a supersaturated cocrystal solution through a fundamental understanding of the nucleation and crystal growth is important. In this study, the influence of the three polymers of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and a copolymer of N-vinly-2-pyrrodidone (60%) and vinyl acetate (40%) (PVP-VA) on the flufenamic acid (FFA) crystallization from three different supersaturated solutions of the pure FFA and two cocrystals of FFA-NIC CO and FFA-TP CO has been investigated by measuring nucleation induction times and desupersaturation rates in the presence and absence of seed crystals. It was found that the competition of intermolecular hydrogen bonding among drug/coformer, drug/polymer, and coformer/polymer was a key factor responsible for maintaining supersaturation through nucleation inhibition and crystal growth modification in a cocrystal solution. The supersaturated cocrystal solutions with predissolved PEG demonstrated more effective stabilization in comparison to the pure FFA in the presence of the same polymer. In contrast, neither of the two cocrystal solutions, in the presence of PVP or PVP-VA, exhibited a better performance than the pure FFA with the same predissolved polymer. The study suggests that the selection of a polymeric excipient in a cocrystal formulation should not be solely dependent on the interplay of the parent drug and polymer without considering the coformer effects. PMID:27494289

  11. The saturated fatty acid, palmitic acid, induces anxiety-like behavior in mice

    PubMed Central

    Moon, Morgan L.; Joesting, Jennifer J.; Lawson, Marcus A.; Chiu, Gabriel S.; Blevins, Neil A.; Kwakwa, Kristin A.; Freund, Gregory G.

    2014-01-01

    Objectives Excess fat in the diet can impact neuropsychiatric functions by negatively affecting cognition, mood and anxiety. We sought to show that the free fatty acid (FFA), palmitic acid, can cause adverse biobehaviors in mice that lasts beyond an acute elevation in plasma FFAs. Methods Mice were administered palmitic acid or vehicle as a single intraperitoneal (IP) injection. Biobehaviors were profiled 2 and 24 hrs after palmitic acid treatment. Quantification of dopamine (DA), norepinephrine (NE), serotonin (5-HT) and their major metabolites was performed in cortex, hippocampus and amygdala. FFA concentration was determined in plasma. Relative fold change in mRNA expression of unfolded protein response (UPR)-associated genes was determined in brain regions. Results In a dose-dependent fashion, palmitic acid rapidly reduced mouse locomotor activity by a mechanism that did not rely on TLR4, MyD88, IL-1, IL-6 or TNFα but was dependent on fatty acid chain length. Twenty-four hrs after palmitic acid administration mice exhibited anxiety-like behavior without impairment in locomotion, food intake, depressive-like behavior or spatial memory. Additionally, the serotonin metabolite 5-HIAA was increased by 33% in the amygdala 24 hrs after palmitic acid treatment. Conclusions Palmitic acid induces anxiety-like behavior in mice while increasing amygdala-based serotonin metabolism. These effects occur at a time point when plasma FFA levels are no longer elevated. PMID:25016520

  12. Comparative proteomic analysis of engineered Saccharomyces cerevisiae with enhanced free fatty acid accumulation.

    PubMed

    Chen, Liwei; Lee, Jaslyn Jie Lin; Zhang, Jianhua; Chen, Wei Ning

    2016-02-01

    The engineered Saccharomyces cerevisiae strain △faa1△faa4 [Acot5s] was demonstrated to accumulate more free fatty acids (FFA) previously. Here, comparative proteomic analysis was performed to get a global overview of metabolic regulation in the strain. Over 500 proteins were identified, and 82 of those proteins were found to change significantly in the engineered strains. Proteins involved in glycolysis, acetate metabolism, fatty acid synthesis, TCA cycle, glyoxylate cycle, the pentose phosphate pathway, respiration, transportation, and stress response were found to be upregulated in △faa1△faa4 [Acot5s] as compared to the wild type. On the other hand, proteins involved in glycerol, ethanol, ergosterol, and cell wall synthesis were downregulated. Taken together with our metabolite analysis, our results showed that the disruption of Faa1 and Faa4 and expression of Acot5s in the engineered strain △faa1△faa4 [Acot5s] not only relieved the feedback inhibition of fatty acyl-CoAs on fatty acid synthesis, but also caused a major metabolic rearrangement. The rearrangement redirected carbon flux toward the pathways which generate the essential substrates and cofactors for fatty acid synthesis, such as acetyl-CoA, ATP, and NADPH. Therefore, our results help shed light on the mechanism for the increased production of fatty acids in the engineered strains, which is useful in providing information for future studies in biofuel production. PMID:26450510

  13. Characterization of acid flux in osteoclasts from patients harboring a G215R mutation in ClC-7

    SciTech Connect

    Henriksen, Kim Gram, Jeppe Neutzsky-Wulff, Anita Vibsig Jensen, Vicki Kaiser Dziegiel, Morten H. Bollerslev, Jens Karsdal, Morten A.

    2009-01-23

    The chloride-proton antiporter ClC-7 has been speculated to be involved in acidification of the lysosomes and the resorption lacunae in osteoclasts; however, neither direct measurements of chloride transport nor acidification have been performed. Human osteoclasts harboring a dominant negative mutation in ClC-7 (G215R) were isolated, and used these to investigate bone resorption measured by CTX-I, calcium release and pit scoring. The actin cytoskeleton of the osteoclasts was also investigated. ClC-7 enriched membranes from the osteoclasts were isolated, and used to test acidification rates in the presence of a V-ATPase and a chloride channel inhibitor, using a H{sup +} and Cl{sup -} driven approach. Finally, acidification rates in ClC-7 enriched membranes from ADOII osteoclasts and their corresponding controls were compared. Resorption by the G215R osteoclasts was reduced by 60% when measured by both CTX-I, calcium release, and pit area when comparing to age and sex matched controls. In addition, the ADOII osteoclasts showed no differences in actin ring formation. Finally, V-ATPase and chloride channel inhibitors completely abrogated the H{sup +} and Cl{sup -} driven acidification. Finally, the acid influx was reduced by maximally 50% in the ClC-7 deficient membrane fractions when comparing to controls. These data demonstrate that ClC-7 is essential for bone resorption, via its role in acidification of the lysosomes and resorption lacunae in osteoclasts.

  14. Effect of a p38 MAPK inhibitor on FFA-induced hepatic insulin resistance in vivo

    PubMed Central

    Pereira, S; Yu, W Q; Moore, J; Mori, Y; Tsiani, E; Giacca, A

    2016-01-01

    The mechanisms whereby prolonged plasma free fatty acids elevation, as found in obesity, causes hepatic insulin resistance are not fully clarified. We herein investigated whether inhibition of p38 mitogen-activated protein kinase (MAPK) prevented hepatic insulin resistance following prolonged lipid infusion. Chronically cannulated rats were subdivided into one of four intravenous (i.v.) treatments that lasted 48 h: Saline (5.5 μl min−1), Intralipid plus heparin (IH, 20% Intralipid+20 U ml−1 heparin; 5.5 μl min−1), IH+p38 MAPK inhibitor (SB239063) and SB239063 alone. During the last 2 h of treatment, a hyperinsulinemic (5 mU kg−1 min−1) euglycemic clamp together with [3-3H] glucose methodology was carried out to distinguish hepatic from peripheral insulin sensitivity. We found that SB239063 prevented IH-induced hepatic insulin resistance, but not peripheral insulin resistance. SB239063 also prevented IH-induced phosphorylation of activating transcription factor 2 (ATF2), a marker of p38 MAPK activity, in the liver. Moreover, in another lipid infusion model in mice, SB239063 prevented hepatic but not peripheral insulin resistance caused by 48 h combined ethyloleate plus ethylpalmitate infusion. Our results suggest that inhibition of p38 MAPK may be a useful strategy in alleviating hepatic insulin resistance in obesity-associated disorders. PMID:27136448

  15. Effect of a p38 MAPK inhibitor on FFA-induced hepatic insulin resistance in vivo.

    PubMed

    Pereira, S; Yu, W Q; Moore, J; Mori, Y; Tsiani, E; Giacca, A

    2016-01-01

    The mechanisms whereby prolonged plasma free fatty acids elevation, as found in obesity, causes hepatic insulin resistance are not fully clarified. We herein investigated whether inhibition of p38 mitogen-activated protein kinase (MAPK) prevented hepatic insulin resistance following prolonged lipid infusion. Chronically cannulated rats were subdivided into one of four intravenous (i.v.) treatments that lasted 48 h: Saline (5.5 μl min(-1)), Intralipid plus heparin (IH, 20% Intralipid+20 U ml(-1) heparin; 5.5 μl min(-1)), IH+p38 MAPK inhibitor (SB239063) and SB239063 alone. During the last 2 h of treatment, a hyperinsulinemic (5 mU kg(-1) min(-1)) euglycemic clamp together with [3-(3)H] glucose methodology was carried out to distinguish hepatic from peripheral insulin sensitivity. We found that SB239063 prevented IH-induced hepatic insulin resistance, but not peripheral insulin resistance. SB239063 also prevented IH-induced phosphorylation of activating transcription factor 2 (ATF2), a marker of p38 MAPK activity, in the liver. Moreover, in another lipid infusion model in mice, SB239063 prevented hepatic but not peripheral insulin resistance caused by 48 h combined ethyloleate plus ethylpalmitate infusion. Our results suggest that inhibition of p38 MAPK may be a useful strategy in alleviating hepatic insulin resistance in obesity-associated disorders. PMID:27136448

  16. Increased abscisic acid levels in transgenic maize overexpressing AtLOS5 mediated root ion fluxes and leaf water status under salt stress.

    PubMed

    Zhang, Juan; Yu, Haiyue; Zhang, Yushi; Wang, Yubing; Li, Maoying; Zhang, Jiachang; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2016-03-01

    Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na(+) efflux and H(+) influx, but decreased net K(+) efflux, which maintained a high cytosolic K(+)/Na(+) ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K(+) effluxes and decrease Na(+) efflux and H(+) influx in salt-treated transgenic roots, but the K(+) effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na(+)/H(+) antiport and K(+) channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K(+) and Na(+) homeostasis and better water status in maize exposed to salt stress. PMID:26743432

  17. Increased abscisic acid levels in transgenic maize overexpressing AtLOS5 mediated root ion fluxes and leaf water status under salt stress

    PubMed Central

    Zhang, Juan; Yu, Haiyue; Zhang, Yushi; Wang, Yubing; Li, Maoying; Zhang, Jiachang; Duan, Liusheng; Zhang, Mingcai; Li, Zhaohu

    2016-01-01

    Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na+ efflux and H+ influx, but decreased net K+ efflux, which maintained a high cytosolic K+/Na+ ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K+ effluxes and decrease Na+ efflux and H+ influx in salt-treated transgenic roots, but the K+ effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na+/H+ antiport and K+ channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K+ and Na+ homeostasis and better water status in maize exposed to salt stress. PMID:26743432

  18. Pancreatic islet function in omega-3 fatty acid-depleted rats: alteration of calcium fluxes and calcium-dependent insulin release.

    PubMed

    Zhang, Y; Oguzhan, B; Louchami, K; Chardigny, J-M; Portois, L; Carpentier, Y A; Malaisse, W J; Herchuelz, A; Sener, A

    2006-09-01

    Considering the insufficient supply of long-chain polyunsaturated omega-3 fatty acids often prevailing in Western populations, this report deals mainly with alterations of Ca(2+) fluxes and Ca(2+)-dependent insulin secretory events in isolated pancreatic islets from omega-3-depleted rats. In terms of (45)Ca(2+) handling, the islets from omega-3-depleted rats, compared with those from normal animals, displayed an unaltered responsiveness to an increase in extracellular K(+) concentration, a lower inflow rate and lower fractional outflow rate of the divalent cation, and higher (45)Ca(2+)-labeled cellular pool(s) at isotopic equilibrium. The latter anomaly was corrected 120 min after intravenous injection of a novel medium-chain triglyceride-fish oil (MCT:FO) emulsion, distinct from a control omega-3-poor MCT-olive oil (MCT:OO) emulsion. At 8.3 mM D-glucose, insulin release was higher in islets from omega-3-depleted rats vs. control animals, coinciding with a higher cytosolic Ca(2+) concentration. The relative magnitude of the increase in insulin output attributable to a rise in D-glucose as well as extracellular Ca(2+) or K(+) concentration, to the absence vs. presence of verapamil and to the presence vs. absence of extracellular Ca(2+), theophylline, phorbol 12-myristate 13-acetate, or Ba(2+), was always more pronounced in islets from omega-3-depleted rats injected with the MCT:OO compared with the MCT:FO emulsion. A comparable situation prevailed when comparing islets from noninjected omega-3-depleted and normal rats. In light of these and previous findings, we propose that an impairment of Na(+),K(+)-ATPase activity plays a major, although not an exclusive, role in the perturbation of Ca(2+) fluxes and Ca(2+)-dependent secretory events in the islets from omega-3-depleted rats. PMID:16912059

  19. Flux analysis of the Lactobacillus reuteri propanediol-utilization pathway for production of 3-hydroxypropionaldehyde, 3-hydroxypropionic acid and 1,3-propanediol from glycerol

    PubMed Central

    2014-01-01

    Background Lactobacillus reuteri converts glycerol to 3-hydroxypropionic acid (3HP) and 1,3-propanediol (1,3PDO) via 3-hydroxypropionaldehyde (3HPA) as an intermediate using enzymes encoded in its propanediol-utilization (pdu) operon. Since 3HP, 1,3PDO and 3HPA are important building blocks for the bio-based chemical industry, L. reuteri can be an attractive candidate for their production. However, little is known about the kinetics of glycerol utilization in the Pdu pathway in L. reuteri. In this study, the metabolic fluxes through the Pdu pathway were determined as a first step towards optimizing the production of 3HPA, and co-production of 3HP and 1,3PDO from glycerol. Resting cells of wild-type (DSM 20016) and recombinant (RPRB3007, with overexpressed pdu operon) strains were used as biocatalysts. Results The conversion rate of glycerol to 3HPA by the resting cells of L. reuteri was evaluated by in situ complexation of the aldehyde with carbohydrazide to avoid the aldehyde-mediated inactivation of glycerol dehydratase. Under operational conditions, the specific 3HPA production rate of the RPRB3007 strain was 1.9 times higher than that of the wild-type strain (1718.2 versus 889.0 mg/gCDW.h, respectively). Flux analysis of glycerol conversion to 1,3PDO and 3HP in the cells using multi-step variable-volume fed-batch operation showed that the maximum specific production rates of 3HP and 1,3PDO were 110.8 and 93.7 mg/gCDW.h, respectively, for the wild-type strain, and 179.2 and 151.4 mg/gCDW.h, respectively, for the RPRB3007 strain. The cumulative molar yield of the two compounds was ~1 mol/mol glycerol and their molar ratio was ~1 mol3HP/mol1,3PDO. A balance of redox equivalents between the glycerol oxidative and reductive pathway branches led to equimolar amounts of the two products. Conclusions Metabolic flux analysis was a useful approach for finding conditions for maximal conversion of glycerol to 3HPA, 3HP and 1,3PDO. Improved specific production rates were

  20. Plasma long-chain free fatty acids predict mammalian longevity

    PubMed Central

    Jové, Mariona; Naudí, Alba; Aledo, Juan Carlos; Cabré, Rosanna; Ayala, Victoria; Portero-Otin, Manuel; Barja, Gustavo; Pamplona, Reinald

    2013-01-01

    Membrane lipid composition is an important correlate of the rate of aging of animals and, therefore, the determination of their longevity. In the present work, the use of high-throughput technologies allowed us to determine the plasma lipidomic profile of 11 mammalian species ranging in maximum longevity from 3.5 to 120 years. The non-targeted approach revealed a specie-specific lipidomic profile that accurately predicts the animal longevity. The regression analysis between lipid species and longevity demonstrated that the longer the longevity of a species, the lower is its plasma long-chain free fatty acid (LC-FFA) concentrations, peroxidizability index, and lipid peroxidation-derived products content. The inverse association between longevity and LC-FFA persisted after correction for body mass and phylogenetic interdependence. These results indicate that the lipidomic signature is an optimized feature associated with animal longevity, emerging LC-FFA as a potential biomarker of longevity. PMID:24284984

  1. Boric acid flux synthesis, structure and magnetic property of MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn)

    SciTech Connect

    Yang, Dingfeng; Cong, Rihong; Gao, Wenliang; Yang, Tao

    2013-05-01

    Three new borates MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn) have been synthesized by boric acid flux methods, which are isotypic to NiB₁₂O₁₄(OH)₁₀. Single-crystal XRD was performed to determine the crystal structures in detail. They all crystallize in the monoclinic space group P2₁/c. The size of MO{sub 6} (M=Mg, Mn, Fe, Co, Ni, Zn) octahedron shows a good agreement with the Shannon effective ionic radii of M²⁺. Magnetic measurements indicate MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering down to 2 K. The values of its magnetic superexchange constants were evaluated by DFT calculations, which explain the observed magnetic behavior. The UV–vis diffuse reflectance spectrum of ZnB₁₂O₁₄(OH)₁₀ suggests a band gap ~4.6 eV. DFT calculations indicate it has a direct band gap 4.9 eV. The optical band gap is contributed by charge transfers from the occupied O 2p to the unoccupied Zn 4s states. - Graphical abstract: Experimental and theoretical studies indicate MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering. DFT calculations show ZnB₁₂O₁₄(OH)₁₀ has a direct band gap of 4.9 eV. Highlights: • MB₁₂O₁₄(OH)₁₀ (M=Mn, Fe, Zn) are synthesized by two-step boric acid flux method. • Single-crystal XRD was performed to determine the crystal structures in detail. • Size of MO₆ (M=Mg, Mn, Fe, Co, Ni, Zn) agrees with the effective ionic radii. • MnB₁₂O₁₄(OH)₁₀ is antiferromagnetic without a long-range ordering down to 2 K. • DFT calculations indicate ZnB₁₂O₁₄(OH)₁₀ has a direct band gap 4.9 eV.

  2. The Anterior Temporal Face Area Contains Invariant Representations of Face Identity That Can Persist Despite the Loss of Right FFA and OFA.

    PubMed

    Yang, Hua; Susilo, Tirta; Duchaine, Bradley

    2016-03-01

    Macaque neurophysiology found image-invariant representations of face identity in a face-selective patch in anterior temporal cortex. A face-selective area in human anterior temporal lobe (fATL) has been reported, but has not been reliably identified, and its function and relationship with posterior face areas is poorly understood. Here, we used fMRI adaptation and neuropsychology to ask whether fATL contains image-invariant representations of face identity, and if so, whether these representations require normal functioning of fusiform face area (FFA) and occipital face area (OFA). We first used a dynamic localizer to demonstrate that 14 of 16 normal subjects exhibit a highly selective right fATL. Next, we found evidence that this area subserves image-invariant representation of identity: Right fATL showed repetition suppression to the same identity across different images, while other areas did not. Finally, to examine fATL's relationship with posterior areas, we used the same procedures with Galen, an acquired prosopagnosic who lost right FFA and OFA. Despite the absence of posterior face areas, Galen's right fATL preserved its face selectivity and showed repetition suppression comparable to that in controls. Our findings suggest that right fATL contains image-invariant face representations that can persist despite the absence of right FFA and OFA, but these representations are not sufficient for normal face recognition. PMID:25527821

  3. Comparison and validation of 2 analytical methods for the determination of free fatty acids in dairy products by gas chromatography with flame ionization detection.

    PubMed

    Mannion, David T; Furey, Ambrose; Kilcawley, Kieran N

    2016-07-01

    Accurate quantification of free fatty acids (FFA) in dairy products is important for quality control, nutritional, antimicrobial, authenticity, legislative, and flavor purposes. In this study, the performance of 2 widely used gas chromatographic flame ionization detection methods for determination of FFA in dairy products differing in lipid content and degree of lipolysis were evaluated. We used a direct on-column approach where the isolated FFA extract was injected directly and a derivatization approach where the FFA were esterified in the injector to methyl esters using tetramethylammonium hydroxide as a catalyst. A comprehensive validation was undertaken to establish method linearity, limits of detection, limits of quantification, accuracy, and precision. Linear calibrations of 3 to 700mg/L (R(2)>0.999) and 20 to 700mg/L (R(2)>0.997), and limits of detection and limits of quantification of 0.7 and 3mg/L and 5 and 20mg/L were obtained for the direct injection on-column and the derivatization method, respectively. Intraday precision of 1.5 to 7.2% was obtained for both methods. The direct injection on-column method had the lower levels of limits of detection and quantification, because FFA are directly injected onto the GC as opposed to the split injection used in the derivatization method. However, the direct injection on-column method experienced accumulative column phase deterioration and irreversible FFA absorption because of the acidic nature of the injection extract, which adversely affected method robustness and the quantification of some longer chain FFA. The derivatization method experienced issues with quantification of butyric acid at low concentrations because of coelution with the injection solvent peak, loss of polyunsaturated FFA due to degradation by tetramethylammonium hydroxide, and the periodic emergence of by-product peaks of the tetramethylammonium hydroxide reaction that interfered with the quantification of some short-chain FFA. The

  4. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity.

    PubMed

    Patterson, Rainey E; Kalavalapalli, Srilaxmi; Williams, Caroline M; Nautiyal, Manisha; Mathew, Justin T; Martinez, Janie; Reinhard, Mary K; McDougall, Danielle J; Rocca, James R; Yost, Richard A; Cusi, Kenneth; Garrett, Timothy J; Sunny, Nishanth E

    2016-04-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH. PMID:26814015

  5. A Novel Allosteric Activator of Free Fatty Acid 2 Receptor Displays Unique Gi-functional Bias*

    PubMed Central

    Bolognini, Daniele; Moss, Catherine E.; Nilsson, Karolina; Petersson, Annika U.; Donnelly, Iona; Sergeev, Eugenia; König, Gabriele M.; Kostenis, Evi; Kurowska-Stolarska, Mariola; Miller, Ashley; Dekker, Niek; Tobin, Andrew B.

    2016-01-01

    The short chain fatty acid receptor FFA2 is able to stimulate signaling via both Gi- and Gq/G11-promoted pathways. These pathways are believed to control distinct physiological end points but FFA2 receptor ligands appropriate to test this hypothesis have been lacking. Herein, we characterize AZ1729, a novel FFA2 regulator that acts as a direct allosteric agonist and as a positive allosteric modulator, increasing the activity of the endogenously produced short chain fatty acid propionate in Gi-mediated pathways, but not at those transduced by Gq/G11. Using AZ1729 in combination with direct inhibitors of Gi and Gq/G11 family G proteins demonstrated that although both arms contribute to propionate-mediated regulation of phospho-ERK1/2 MAP kinase signaling in FFA2-expressing 293 cells, the Gq/G11-mediated pathway is predominant. We extend these studies by employing AZ1729 to dissect physiological FFA2 signaling pathways. The capacity of AZ1729 to act at FFA2 receptors to inhibit β-adrenoreceptor agonist-promoted lipolysis in primary mouse adipocytes and to promote chemotaxis of isolated human neutrophils confirmed these as FFA2 processes mediated by Gi signaling, whereas, in concert with blockade by the Gq/G11 inhibitor FR900359, the inability of AZ1729 to mimic or regulate propionate-mediated release of GLP-1 from mouse colonic preparations defined this physiological response as an end point transduced via activation of Gq/G11. PMID:27385588

  6. A Novel Allosteric Activator of Free Fatty Acid 2 Receptor Displays Unique Gi-functional Bias.

    PubMed

    Bolognini, Daniele; Moss, Catherine E; Nilsson, Karolina; Petersson, Annika U; Donnelly, Iona; Sergeev, Eugenia; König, Gabriele M; Kostenis, Evi; Kurowska-Stolarska, Mariola; Miller, Ashley; Dekker, Niek; Tobin, Andrew B; Milligan, Graeme

    2016-09-01

    The short chain fatty acid receptor FFA2 is able to stimulate signaling via both Gi- and Gq/G11-promoted pathways. These pathways are believed to control distinct physiological end points but FFA2 receptor ligands appropriate to test this hypothesis have been lacking. Herein, we characterize AZ1729, a novel FFA2 regulator that acts as a direct allosteric agonist and as a positive allosteric modulator, increasing the activity of the endogenously produced short chain fatty acid propionate in Gi-mediated pathways, but not at those transduced by Gq/G11 Using AZ1729 in combination with direct inhibitors of Gi and Gq/G11 family G proteins demonstrated that although both arms contribute to propionate-mediated regulation of phospho-ERK1/2 MAP kinase signaling in FFA2-expressing 293 cells, the Gq/G11-mediated pathway is predominant. We extend these studies by employing AZ1729 to dissect physiological FFA2 signaling pathways. The capacity of AZ1729 to act at FFA2 receptors to inhibit β-adrenoreceptor agonist-promoted lipolysis in primary mouse adipocytes and to promote chemotaxis of isolated human neutrophils confirmed these as FFA2 processes mediated by Gi signaling, whereas, in concert with blockade by the Gq/G11 inhibitor FR900359, the inability of AZ1729 to mimic or regulate propionate-mediated release of GLP-1 from mouse colonic preparations defined this physiological response as an end point transduced via activation of Gq/G11. PMID:27385588

  7. Effects of weight loss via high fat vs. low fat alternate day fasting diets on free fatty acid profiles.

    PubMed

    Varady, Krista A; Dam, Vi T; Klempel, Monica C; Horne, Matthew; Cruz, Rani; Kroeger, Cynthia M; Santosa, Sylvia

    2015-01-01

    Cardiovascular disease risk is associated with excess body weight and elevated plasma free fatty acid (FFA) concentrations. This study examines how an alternate-day fasting (ADF) diet high (HF) or low (LF) in fat affects plasma FFA profiles in the context of weight loss, and changes in body composition and lipid profiles. After a 2-week weight maintenance period, 29 women (BMI 30-39.9 kg/m(2)) 25-65 years old were randomized to an 8-week ADF-HF (45% fat) diet or an ADF-LF (25% fat) diet with 25% energy intake on fast days and ad libitum intake on feed days. Body weight, BMI and waist circumference were assessed weekly and body composition was measured using dual x-ray absorptiometry (DXA). Total and individual FFA and plasma lipid concentrations were measured before and after weight loss. Body weight, BMI, fat mass, total cholesterol, LDL-C and triglyceride concentrations decreased (P < 0.05) in both groups. Total FFA concentrations also decreased (P < 0.001). In the ADF-LF group, decreases were found in several more FFAs than in the ADF-HF group. In the ADF-HF group, FFA concentrations were positively correlated with waist circumference. Depending on the macronutrient composition of a diet, weight loss with an ADF diet decreases FFA concentrations through potentially different mechanisms. PMID:25557754

  8. Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men.

    PubMed

    Brands, Myrte; Hoeks, Joris; Sauerwein, Hans P; Ackermans, Mariette T; Ouwens, Margriet; Lammers, Nicolette M; van der Plas, Mart N; Schrauwen, Patrick; Groen, Albert K; Serlie, Mireille J

    2011-10-01

    Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in human skeletal muscle. Whether FAs have a direct effect on intrinsic mitochondrial capacity remains to be established. Therefore, we measured ex vivo mitochondrial respiratory capacity in human skeletal muscle after exposure to hyperinsulinemia and high levels of plasma FFA. Nine healthy lean men were studied during a 6-hour hyperinsulinemic (600 pmol/L) euglycemic clamp with concomitant infusion of Intralipid (Fresensius Kabi Nederland, Den Bosch, the Netherlands) (FFA clamped at 0.5 mmol/L) or saline. Mitochondrial respiratory capacity was measured by high-resolution respirometry in permeabilized muscle fibers using an Oxygraph (OROBOROS Instruments, Innsbruck, Austria). Each participant served as his own control. Peripheral glucose uptake (rate of disappearance) was significantly lower during infusion of the lipid emulsion compared with the control saline infusion (68 μmol/kg·min [saline] vs 40 μmol/kg·min [lipid], P = .008). However, adenosine diphosphate-stimulated and maximal carbonylcyanide-4-(trifluoromethoxy)-phenylhydrazone-stimulated uncoupled respiration rates were not different in permeabilized skeletal muscle fibers after exposure to high levels of FFA compared with the control condition. We conclude that short-term elevation of FFA within the physiological range induces insulin resistance but does not affect intrinsic mitochondrial capacity in skeletal muscle in humans. PMID:21489571

  9. The In vitro Effects of Nano-encapsulated Conjugated Linoleic Acid on Stability of Conjugated Linoleic Acid and Fermentation Profiles in the Rumen.

    PubMed

    Heo, Wan; Kim, Eun Tae; Cho, Sung Do; Kim, Jun Ho; Kwon, Seong Min; Jeong, Ha Yeon; Ki, Kwang Seok; Yoon, Ho Baek; Ahn, Young Dae; Lee, Sung Sill; Kim, Young Jun

    2016-03-01

    This study was aimed to evaluate the stability of conjugated linoleic acids (CLAs) by nano-encapsulation against in vitro ruminal biohydrogenation by microbial enzymatic conversion. CLAs (free fatty acid form of CLA [CLA-FFA], nano-encapsulated CLA-FFA, triglyceride form of CLA [CLA-TG], and nano-encapsulated CLA-TG) were used in the in vitro fermentation experiments. When Butyrivibrio fibrisolvens (B. fibrisolvens) was incubated with CLA-FFAs, the concentrations of cis-9, trans-11 CLA and vaccenic acid (VA) slightly was decreased and increased by nano-encapsulation, respectively. When B. fibrisolvens was incubated with CLA-TG, the concentrations of cis-9, trans-11 CLA and VA decreased, but these were increased when B. fibrisolvens was incubated with nano-encapsulated CLA-TG. The nano-encapsulation was more effective against the in vitro biohydrogenation activity of B.fibrisolvens incubated with CLA-FFA than with CLA-TG. In the in vitro ruminal incubation test, the total gas production and concentration of total volatile fatty acids incubated with nano-encapsulated CLA-FFA and CLA-TG were increased significantly after 24 h incubation (p<0.05). Nano-encapsulated CLA-FFA might, thus, improve the ruminal fermentation characteristics without adverse effects on the incubation process. In addition, nano-encapsulated CLA-FFA increased the population of Fibrobacter succinogenes and decreased the population of B. fibrisolvens population. These results indicate that nano-encapsulation could be applied to enhance CLA levels in ruminants by increasing the stability of CLA without causing adverse effects on ruminal fermentation. PMID:26950867

  10. The In vitro Effects of Nano-encapsulated Conjugated Linoleic Acid on Stability of Conjugated Linoleic Acid and Fermentation Profiles in the Rumen

    PubMed Central

    Heo, Wan; Kim, Eun Tae; Cho, Sung Do; Kim, Jun Ho; Kwon, Seong Min; Jeong, Ha Yeon; Ki, Kwang Seok; Yoon, Ho Baek; Ahn, Young Dae; Lee, Sung Sill; Kim, Young Jun

    2016-01-01

    This study was aimed to evaluate the stability of conjugated linoleic acids (CLAs) by nano-encapsulation against in vitro ruminal biohydrogenation by microbial enzymatic conversion. CLAs (free fatty acid form of CLA [CLA-FFA], nano-encapsulated CLA-FFA, triglyceride form of CLA [CLA-TG], and nano-encapsulated CLA-TG) were used in the in vitro fermentation experiments. When Butyrivibrio fibrisolvens (B. fibrisolvens) was incubated with CLA-FFAs, the concentrations of cis-9, trans-11 CLA and vaccenic acid (VA) slightly was decreased and increased by nano-encapsulation, respectively. When B. fibrisolvens was incubated with CLA-TG, the concentrations of cis-9, trans-11 CLA and VA decreased, but these were increased when B. fibrisolvens was incubated with nano-encapsulated CLA-TG. The nano-encapsulation was more effective against the in vitro biohydrogenation activity of B.fibrisolvens incubated with CLA-FFA than with CLA-TG. In the in vitro ruminal incubation test, the total gas production and concentration of total volatile fatty acids incubated with nano-encapsulated CLA-FFA and CLA-TG were increased significantly after 24 h incubation (p<0.05). Nano-encapsulated CLA-FFA might, thus, improve the ruminal fermentation characteristics without adverse effects on the incubation process. In addition, nano-encapsulated CLA-FFA increased the population of Fibrobacter succinogenes and decreased the population of B. fibrisolvens population. These results indicate that nano-encapsulation could be applied to enhance CLA levels in ruminants by increasing the stability of CLA without causing adverse effects on ruminal fermentation. PMID:26950867

  11. Dose-response effect of elevated plasma free fatty acid on insulin signaling.

    PubMed

    Belfort, Renata; Mandarino, Lawrence; Kashyap, Sangeeta; Wirfel, Kelly; Pratipanawatr, Thongchai; Berria, Rachele; Defronzo, Ralph A; Cusi, Kenneth

    2005-06-01

    The dose-response relationship between elevated plasma free fatty acid (FFA) levels and impaired insulin-mediated glucose disposal and insulin signaling was examined in 21 lean, healthy, normal glucose-tolerant subjects. Following a 4-h saline or Liposyn infusion at 30 (n = 9), 60 (n = 6), and 90 (n = 6) ml/h, subjects received a 2-h euglycemic insulin (40 mU . m(-2) . min(-1)) clamp. Basal plasma FFA concentration ( approximately 440 micromol/l) was increased to 695, 1,251, and 1,688 micromol/l after 4 h of Liposyn infusion and resulted in a dose-dependent reduction in insulin-stimulated glucose disposal (R(d)) by 22, 30, and 34%, respectively (all P < 0.05 vs. saline control). At the lowest lipid infusion rate (30 ml/h), insulin receptor and insulin receptor substrate (IRS)-1 tyrosine phosphorylation, phosphatidylinositol (PI) 3-kinase activity associated with IRS-1, and Akt serine phosphorylation were all significantly impaired (P < 0.05-0.01). The highest lipid infusion rate (90 ml/h) caused a further significant reduction in all insulin signaling events compared with the low-dose lipid infusion (P < 0.05-0.01) whereas the 60-ml/h lipid infusion caused an intermediate reduction in insulin signaling. However, about two-thirds of the maximal inhibition of insulin-stimulated glucose disposal already occurred at the rather modest increase in plasma FFA induced by the low-dose (30-ml/h) lipid infusion. Insulin-stimulated glucose disposal was inversely correlated with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.50, P = 0.001) and the plasma FFA level during the last 30 min of the insulin clamp (r = -0.54, P < 0.001). PI 3-kinase activity associated with IRS-1 correlated with insulin-stimulated glucose disposal (r = 0.45, P < 0.01) and inversely with both the plasma FFA concentration after 4 h of lipid infusion (r = -0.39, P = 0.01) and during the last 30 min of the insulin clamp (r = -0.43, P < 0.01). In summary, in skeletal muscle of lean

  12. Theme: Changing the FFA.

    ERIC Educational Resources Information Center

    Moss, Jeffrey W.; And Others

    1990-01-01

    Seven issues in this theme issue focus on the need for change in the National Future Farmers of America Organization. The authors stress that change will produce a larger and stronger membership that understands and values the existence of agricultural education as a tool in building tomorrow's leaders. (Author/JOW)

  13. Synthesis and biological evaluation of phenoxyacetic acid derivatives as novel free fatty acid receptor 1 agonists.

    PubMed

    Wang, Xuekun; Zhao, Tianxiao; Yang, Baowei; Li, Zheng; Cui, Jian; Dai, Yuxuan; Qiu, Qianqian; Qiang, Hao; Huang, Wenlong; Qian, Hai

    2015-01-01

    Free fatty acid receptor 1 (FFA1) is a new potential drug target for the treatment of type 2 diabetes because of its role in amplifying glucose-stimulated insulin secretion in pancreatic β-cell. In the present studies, we identified phenoxyacetic acid derivative (18b) as a potent FFA1 agonist (EC50=62.3 nM) based on the structure of phenylpropanoic acid derivative 4p. Moreover, compound 18b could significantly improve oral glucose tolerance in ICR mice and dose-dependently reduced glucose levels in type 2 diabetic C57BL/6 mice without observation of hypoglycemic side effect. Additionally, compound 18b exhibited acceptable PK profiles. In summary, compound 18b with ideal PK profiles exhibited good activity in vitro and in vivo, and might be a promising drug candidate for the treatment of diabetes mellitus. PMID:25481394

  14. Recognition of a Biofilm at the Sediment-Water Interface of AN Acid Mine Drainage-Contaminated Stream, and its Role in Controlling Iron Flux

    NASA Astrophysics Data System (ADS)

    Boult, Stephen; Johnson, Nicholas; Curtis, Charles

    1997-03-01

    Material collected over a month on plates attached to the bed of the Afon Goch, Anglesey, a stream highly contaminated by acid mine drainage (AMD), was either examined intact by electron microscopy or suspended and cultured to reveal the presence of microbiota. Certain of the aerobic microbiota were identified, the genus Pseudomonas formed the commonest isolate and cultures of Serratia plymuthica were grown in order to compare the biofilms formed with the material collected in the Afon Goch. The material at the sediment-water interface of the Afon Goch was of similar underlying morphology to that of the cultured biofilms. However, the former had a superficial granular coating of equidimensional (60-100 nm) and evenly spaced iron rich particles (determined by X-ray microanalysis). The sediment-water interface of this AMD-contaminated stream is therefore best described as a highly contaminated biofilm. Evidence from previous work suggests that the streambed is active in iron removal from the water column. The intimate association of iron with microbiota at the streambed, therefore, implies that iron flux prediction may not be possible from physical and chemical data alone but requires knowledge of biofilm physiology and ecology.Microbially mediated metal precipitation, both by single bacteria and by biofilms, has been reported elsewhere but mass balance considerations suggest that this explanation cannot hold good for the large amounts of iron hydroxide depositing from waters of the prevalent pH and redox status. Filtered stream water analyses indicate the presence of colloidal iron hydroxide and also its removal downstream where ochreous (iron hydroxide rich) material accumulates. The process of iron immobilization is likely to be the attraction and physical trapping of colloidal iron hydroxide by extracellular polymeric substances (EPS) which constitute the matrix of biofilms.

  15. Linoleic acid content of human meibum is associated with telangiectasia and plugging of gland orifices in meibomian gland dysfunction.

    PubMed

    Arita, Reiko; Mori, Naoto; Shirakawa, Rika; Asai, Kei; Imanaka, Takahiro; Fukano, Yasufumi; Nakamura, Masatsugu

    2016-04-01

    To examine the relation between changes in the free fatty acid (FFA) composition of human meibum and both objective signs and subjective symptoms of meibomian gland dysfunction (MGD), we analyzed the FFA content of meibum collected from both MGD patients and control subjects. Thirty-eight patients with MGD (13 men and 25 women; mean age ± SD, 66.9 ± 15.0 years) were evaluated. Various objective signs and subjective symptoms of MGD were assessed. Meibum was analyzed by liquid chromatography-Fourier transform mass spectrometry, and the relation between the FFA composition of meibum and each objective sign and subjective symptom was examined by principal component analysis (PCA). No relation was apparent between the FFA composition of meibum and individual subjective symptoms or objective signs of MGD. However, a PCA score plot for meibum samples grouped on the basis of the severity of both telangiectasia and plugging of meibomian gland orifices revealed clear separation of mild and severe groups. This separation of the two groups was largely due to a significantly increased linoleic acid content in meibum of the severe group (3.56%, versus 0.70% of total FFAs in the mild group). The relative amount of linoleic acid in meibum was thus associated with the severity of telangiectasia and plugging of gland orifices in MGD, suggesting that this FFA might contribute to the pathogenesis of these signs. PMID:26919787

  16. Dietary effects in the early recovery phase of kwashiorkor. Plasma levels of triglycerides, FFA, D-beta-hydroxybutyrate, glycerol, postheparin lipoprotein lipase (LPL), glucose and insulin.

    PubMed

    Persson, B; Habte, D; Sterky, G

    1976-05-01

    The fatty liver often found in untreated kwashiorkor has been associated with highly variable concentration of circulating lipids. The effect on lipid metabolism of two isocaloric diets--one synthetic monomolecular (Vivonex) and one standard (Casilan)--which both initiated satisfactory clinical improvement was studied in 21 Ethiopian children with kwashiorkor during the first weeks of rehabilitation. Before treatment mean fasting values of all biochemical parameters were within normal ranges except for moderately elevated triglycerides--an unexpected finding-and low insulin. Individual values varied greatly; triglyceride between 0.39 and 3.49 mmol/1. FFA correlated both to glycerol, D-beta-hydroxybutyrate and triglyceride values. During treatment insulin, glucose and glycerol remained essentially unchanged and were similar in both dietary groups. In the Vivonex group only there was an initial marked, parallel fall of FFA and D-beta-hydroxybutyrate suggesting greater availability of carbohydrate and enhanced glucose utilization. This pattern of response seemed to occur without comparable inhibition of lipolysis. Triglycerides--like serum albumin--increased faster in the Casilan group. The highest mean triglyceride value was reached by day 8 in the Casilan group and by day 15 in the Vivonex group. Ten minutes following heparin injection triglycerides declined, FFA and glycerol increased indicating release of in vivo active lipase. LPL activity assayed in vitro was similar and unaffected by 2 weeks of dietary treatment in both groups. LPL activity was inversely correlated to triglycerides providing--beside the type of diet--another possible explanation for the wide variations seen in circulatory triglycerides. PMID:1274567

  17. Effects of free fatty acids on meibomian lipid films.

    PubMed

    Arciniega, Juan C; Nadji, Erfan J; Butovich, Igor A

    2011-10-01

    The purpose of this study was to evaluate the impact of free fatty acids (FFA), namely oleic (OA) and linoleic (LA) ones, on meibomian lipid films (MLF) using a Langmuir trough (LT) and a Brewster angle microscope (BAM). Human meibum was collected from healthy volunteers. A Tris-buffered saline (TBS, pH 7.4) was used as the control aqueous subphase for LT experiments. Then, varying amounts of OA and LA were dissolved in TBS to make FFA-containing subphases. Predetermined amounts of meibum were loaded onto the surface of the (TBS/±FFA) subphases to form MLF. Then, surface pressure-area (π/A) isotherms of MLF were recorded. Standard rheological parameters such as rigidity, elasticity, and hysteresis, were computed. In a separate experiment, OA and LA were pre-mixed with meibum at different weight ratios prior their spreading onto the control TBS subphase, and the (π/A) isotherms of the resulting mixed films of meibum and FFA were studied and analyzed in the same fashion as described above. When studied at the normal corneal temperature of 34 °C with the (TBS/-FFA) subphase, meibum formed stable films. When (TBS/+FFA) subphase was used, both FFA quickly disrupted the MLF, acting in a similar fashion. BAM revealed that the most dramatic changes in the structure of MLF occurred in the range of OA concentrations between 5 and 15 μM. However, this effect was apparent even with 2.5 μM OA. When OA was pre-mixed with meibum, but was absent from the subphase, it caused gradual concentration-dependent changes in the (π/A) isotherms, but the MLF did not disappear from the surface. Thus, tested FFA showed a remarkable ability to disrupt, and/or prevent the formation of, human MLF, which could contribute to the onset of those forms of dry eye disease that are associated with enhanced activity of lipolytic enzymes, such as chronic blepharitis. PMID:21718696

  18. Engineering Escherichia coli to synthesize free fatty acids

    PubMed Central

    Lennen, Rebecca M.; Pfleger, Brian F.

    2013-01-01

    Fatty acid metabolism has received significant attention as a route for producing high-energy density, liquid transportation fuels and high-value oleochemicals from renewable feedstocks. If microbes can be engineered to produce these compounds at yields that approach the theoretical limits of 0.3–0.4 g/g glucose, then processes can be developed to replace current petrochemical technologies. Here, we review recent metabolic engineering efforts to maximize production of free fatty acids (FFA) in Escherichia coli, the first step towards production of downstream products. To date, metabolic engineers have succeeded in achieving higher yields of FFA than any downstream products. Regulation of fatty acid metabolism and the physiological effects of fatty acid production will also be reviewed from the perspective of identifying future engineering targets. PMID:23102412

  19. Polysorbate 20 Degradation in Biopharmaceutical Formulations: Quantification of Free Fatty Acids, Characterization of Particulates, and Insights into the Degradation Mechanism.

    PubMed

    Tomlinson, Anthony; Demeule, Barthélemy; Lin, Baiwei; Yadav, Sandeep

    2015-11-01

    Polysorbate 20 (PS20), a commonly used surfactant in biopharmaceuticals, showed degradation upon long-term (∼18-36 months) storage of two monoclonal antibody (mAb, mAb-A, and mAb-B) drug products at 2-8 °C. The PS20 degradation resulted in the accumulation of free fatty acids (FFA), which ultimately precipitated to form particles upon long-term storage. This study documents the development, qualification, and application of a method for FFA quantification in soluble and insoluble fraction of protein formulation. The method was applied to the quantification of capric acid, lauric acid, myristic acid, palmitic/oleic acid, and stearic acid in placebo as well as active protein formulations on stability. Quantification of FFA in both the soluble and insoluble fraction of mAb-A and mAb-B provided a better mechanistic understanding of PS20 degradation and the dynamics of subsequent fatty acid particle formation. Additionally, the use of this method for monitoring and quantitation of the FFA on real time storage stability appears to aid in identifying batches with higher probability for particulate formation upon extended storage at 5 °C. PMID:26419339

  20. Ethanol and fatty acids impair lipid homeostasis in an in vitro model of hepatic steatosis.

    PubMed

    Vecchione, Giulia; Grasselli, Elena; Compalati, Andrea D; Ragazzoni, Milena; Cortese, Katia; Gallo, Gabriella; Voci, Adriana; Vergani, Laura

    2016-04-01

    Excess ethanol consumption and fatty acid intake lead to a cumulative effect on liver steatosis through still unclear mechanisms. This study aimed to characterize the lipid homoeostasis alterations under the exposure of hepatocytes to ethanol alone or combined with fatty acids. FaO hepatoma cells were incubated in the absence (C) or in the presence of 100 mM ethanol (EtOH) or 0.35 mM oleate/palmitate (FFA) alone or in the combination (FFA/EtOH). Content of intra- and extra-cellular triglycerides (TAGs) and of lipid droplets (LDs), expression of lipogenic and lipolytic genes, and oxidative stress-related parameters were evaluated. Exposure to either FFAs or EtOH given separately led to steatosis which was augmented when they were combined. Our results show that FFA/EtOH: (i) increased the LD number, but reduced their size compared to separate treatments; (ii) up-regulated PPARγ and SREBP-1c and down-regulated sirtuin-1 (SIRT1); (iii) impaired FFA oxidation; (iv) did not change lipid secretion and oxidative stress. Our findings indicate that one of the major mechanisms of the metabolic interference between ethanol and fat excess is the impairment of FFA oxidation, in addition to lipogenic pathway stimulation. Interestingly, ethanol combined with FFAs led to a shift from macrovesicular to microvesicular steatosis that represents a more dangerous condition. PMID:26854922

  1. Deacidification of high free fatty acid-containing rice bran oil by non-conventional reesterification process.

    PubMed

    Singh, Sibban; Singh, R P

    2009-01-01

    Rice bran (Oryza sativa) oil is known for containing higher amount of free fatty acid (FFA) generated by hydrolytic enzyme. This FFA causes heavy neutral oil losses due to saponification and emulsification since it produces large amount of soap in the conventional alkali refining process. In the present study the FFA of degummed rice bran oil (RBO) was significantly reduced by reesterifying it with glycerol. The reesterification process was carried out by varying the temperature and amount of excess glycerol using 0.2% catalyst (SnCl(2)). The maximum efficiency of the process could be attained at 200 degrees C using 70% excess glycerol and the maximum reduction in acid value (from 24.3 to 3.0) of RBO was observed within 4 h. The reesterified RBO was used to prepare stand oil and varnish and their performance characteristics were compared with those of the products obtained from dehydrated castor oil (DCO). PMID:19145058

  2. GC-MS/MS survey of collision-induced dissociation of tert-butyldimethylsilyl-derivatized amino acids and its application to (13)C-metabolic flux analysis of Escherichia coli central metabolism.

    PubMed

    Okahashi, Nobuyuki; Kawana, Shuichi; Iida, Junko; Shimizu, Hiroshi; Matsuda, Fumio

    2016-09-01

    Stable isotope labeling experiments using mass spectrometry have been employed to investigate carbon flow levels (metabolic flux) in mammalian, plant, and microbial cells. To achieve a more precise (13)C-metabolic flux analysis ((13)C-MFA), novel fragmentations of tert-butyldimethylsilyl (TBDMS)-amino acids were investigated by gas chromatography-tandem mass spectrometry (GC-MS/MS). The product ion scan analyses of 15 TBDMS-amino acids revealed 24 novel fragment ions. The amino acid-derived carbons included in the five fragment ions were identified by the analyses of (13)C-labeled authentic standards. The identification of the fragment ion at m/z 170 indicated that the isotopic abundance of S-methyl carbon in methionine could be determined from the cleavage of C5 in the precursor of [M-159](+) (m/z 218). It was also confirmed that the precision of (13)C-MFA in Escherichia coli central carbon metabolism could be improved by introducing (13)C-labeling data derived from novel fragmentations. Graphical Abstract Novel collision-induced dissociation fragmentations of tert-butyldimethylsilyl amino acids were investigated and identified by GC-MS/MS. PMID:27342798

  3. Free fatty acids induce a proinflammatory response in islets via the abundantly expressed interleukin-1 receptor I.

    PubMed

    Böni-Schnetzler, Marianne; Boller, Simone; Debray, Sarah; Bouzakri, Karim; Meier, Daniel T; Prazak, Richard; Kerr-Conte, Julie; Pattou, Francois; Ehses, Jan A; Schuit, Frans C; Donath, Marc Y

    2009-12-01

    Islets of patients with type 2 diabetes mellitus (T2DM) display features of an inflammatory process including elevated levels of the cytokine IL-1beta, various chemokines, and macrophages. IL-1beta is a master regulator of inflammation, and IL-1 receptor type I (IL-1RI) blockage improves glycemia and insulin secretion in humans with T2DM and in high-fat-fed mice pointing to a pivotal role of IL-1RI activity in intra-islet inflammation. Given the association of dyslipidemia and T2DM, we tested whether free fatty acids (FFA) promote the expression of proinflammatory factors in human and mouse islets and investigated a role for the IL-1RI in this response. A comparison of 22 mouse tissues revealed the highest IL-1RI expression levels in islets and MIN6 beta-cells. FFA induced IL-1beta, IL-6, and IL-8 in human islets and IL-1beta and KC in mouse islets. Elevated glucose concentrations enhanced FFA-induced proinflammatory factors in human islets. Blocking the IL-1RI with the IL-1R antagonist (IL-1Ra) strongly inhibited FFA-mediated expression of proinflammatory factors in human and mouse islets. Antibody inhibition of IL-1beta revealed that FFA stimulated IL-1RI activity via the induction of the receptor ligand. FFA-induced IL-1beta and KC expression in mouse islets was completely dependent on the IL-1R/Toll-like receptor (TLR) docking protein Myd88 and partly dependent on TLR2 and -4. Activation of TLR2 in purified human beta-cells and islets stimulated the expression of proinflammatory factors, and IL-1RI activity increased the TLR2 response in human islets. We conclude that FFA and TLR stimulation induce proinflammatory factors in islets and that IL-1RI engagement results in signal amplification. PMID:19819943

  4. Hepatitis C Virus Increases Free Fatty Acids Absorption and Promotes its Replication Via Down-Regulating GADD45α Expression

    PubMed Central

    Chen, Wei; Li, Xiao-ming; Li, An-ling; Yang, Gui; Hu, Han-ning

    2016-01-01

    Background Hepatitis C virus (HCV) infection, as a major cause of chronic hepatic diseases, is always accompanied with an abnormality of lipid metabolism. The aim of this study was to investigate the pathogenic role of free fatty acids (FFA) in human HCV infection. Material/Methods Peripheral blood lipid indexes among HCV patients with different viral loads (199 samples) and healthy donors (80 samples) were detected by clinical biochemistry tests. HCV replication and the expression of growth arrest and DNA-damage-inducible gene 45-α (GADD45α) in Huh7 cells and clinical samples were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Lipid accumulation in Huh7 cells was detected by immunofluorescence. Results In this study, we found that FFA showed a significant positive correlation with viral load in peripheral blood of HCV patients, but not total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), or low-density lipoprotein cholesterol (LDL-C). GADD45α expression in HCV patients dramatically decreased with the increase of viral load. In Huh7 cells, FFA treatment significantly enhanced HCV replication. HCV infection inhibited GADD45α expression, and this effect was further enhanced with the presence of FFA treatment. Ectopic expression of GADD45α in HCV-infected Huh7 cells markedly inhibited the absorption of FFA and HCV replication. However, FFA significantly elevated GADD45α expression without HCV infection. Conclusions These results demonstrated that HCV down-regulates GADD45α expression to enhance FFA absorption and thus facilitate its replication. GADD45α is an essential mediator for the pathogenesis of HCV infection. Thus, our study provides potential clues in the search for novel therapeutics and fatty lipid control options for HCV patients. PMID:27381636

  5. Crassulacean Acid Metabolism and Photochemical Efficiency of Photosystem II in the Adaxial and Abaxial Parts of the Succulent Leaves of Kalanchoë daigremontiana Grown at Four Photon Flux Densities.

    PubMed

    Winter, K; Awender, G

    1989-07-01

    Kalanchoë daigremontiana, a species possessing crassulacean acid metabolism, was grown at four photon flux densities (1300, 400, 60, and 25 micromole photons per square meter per second). In leaves which had developed at 1300 and 400 micromole photons per square meter per second, CO(2) was mainly incorporated through the lower, shaded leaf surfaces, and the chlorenchyma adjacent to the lower surfaces showed a higher degree of nocturnal acid synthesis than the chlorenchyma adjacent to the upper surfaces. In leaves acclimated to 60 and 25 micromole photons per square meter per second, the gradient in CAM activity was reversed, i.e. more CO(2) was taken up through the upper than through the lower surfaces and nocturnal acidification was higher in the tissue next to the upper surfaces. Total net carbon gain and total nocturnal acid synthesis were highest in leaves which had developed at 400 micromole photons per square meter per second. Chlorophyll content was markedly reduced in leaves which had developed at 1300 micromole photons per square meter per second, especially in the exposed adaxial parts. There was also a sustained reduction in photosystem II photochemical efficiency as indicated by measurements of the ratio of variable over maximum chlorophyll a fluorescence. These findings suggest that, at high growth photon flux densities, the reduced activity of the exposed portions of these succulent leaves is caused by (a) the adverse effects of excess light, (b) together with a genotypic component which favors CO(2) uptake and acid synthesis in the abaxial (lower) leaf parts even when light is not or only marginally excessive. This latter component is predominant at medium photon flux densities, e.g. at 400 micromole photons per square meter per second. It becomes overridden, however, under conditions of deep shade when strongly reduced light levels in the abaxial parts of the leaf chlorenchyma severely limit photosynthesis. PMID:16666903

  6. Polyamine flux analysis by determination of heavy isotope incorporation from 13C, 15N-enriched amino acids into polyamines by LC-MS/MS.

    PubMed

    Cerrada-Gimenez, Marc; Häkkinen, Merja R; Vepsäläinen, Jouko; Auriola, Seppo; Alhonen, Leena; Keinänen, Tuomo A

    2012-02-01

    The study of polyamine flux, i.e. the circulating flow of polyamines through the interconnected biosynthetic and catabolic pathways, is of considerable interest because of the established links between the polyamine metabolism and many diseases, such as cancer and diabetes. To study polyamine flux in detail, a novel method based on following the label incorporation from the (13)C, (15)N-labeled polyamine precursors, arginine, methionine and ornithine, into polyamines by LC-MS/MS was implemented. This methodology was tested on three distinct cell lines with different spermidine/spermine-N (1)-acetyltransferase (SSAT) expression levels, i.e. non-transgenic, transgenic and knockout. These trials allowed the identification of the critical conditions for the successful polyamine flux measurement, such as the functional time frame of label incorporation, until plateau phase with the selected precursor is reached. The novel LC-MS/MS-based method for polyamine flux overcame the limitations of previous existing methodologies, with baseline separation of the different polyamine species and the exact quantification of the incorporated label. Moreover, the obtained results clearly show that the increased SSAT expression is associated with accelerated polyamine flux. PMID:21818565

  7. Decreased expression of adipose CD36 and FATP1 are associated with increased plasma nonesterified fatty acids during prolonged fasting in northern elephant seal pups (Mirounga angustirostris)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The northern elephant seal undergoes a 2-3 month post-weaning fast during which it depends primarily on the oxidation of fatty acids to meet its energetic demands. The concentration of plasma free fatty acids (FFA) increases and is associated with the development of insulin resistance in late-fasted...

  8. Butyric acid stimulates bovine neutrophil functions and potentiates the effect of platelet activating factor.

    PubMed

    Carretta, M D; Hidalgo, A I; Burgos, J; Opazo, L; Castro, L; Hidalgo, M A; Figueroa, C D; Taubert, A; Hermosilla, C; Burgos, R A

    2016-08-01

    Increased short-chain fatty acid (SCFA) production is associated with subacute ruminal acidosis (SARA) and activation of inflammatory processes. In humans and rodents, SCFAs modulate inflammatory responses in the gut via free fatty acid receptor 2 (FFA2). In bovines, butyric acid is one of the most potent FFA2 agonists. Its expression in bovine neutrophils has recently been demonstrated, suggesting a role in innate immune response in cattle. This study aimed to evaluate if butyric acid modulates oxidative and non-oxidative functions or if it can potentiate other inflammatory mediators in bovine neutrophils. Our results showed that butyric acid can activate bovine neutrophils, inducing calcium (Ca(2+)) influx and mitogen-activated protein kinase (MAPK) phosphorylation, two second messengers involved in FFA2 activation. Ca(2+) influx induced by butyric acid was dependent on the extracellular and intracellular Ca(2+) source and phospholipase C (PLC) activation. Butyric acid alone had no significant effect on reactive oxygen species (ROS) production and chemotaxis; however, a priming effect on platelet-activating factor (PAF), a potent inflammatory mediator, was observed. Butyric acid increased CD63 expression and induced the release of neutrophil granule markers matrix metalloproteinase-9 (MMP-9) and lactoferrin. Finally, we observed that butyric acid induced neutrophil extracellular trap (NET) formation without affecting cellular viability. These findings suggest that butyric acid, a component of the ruminal fermentative process, can modulate the innate immune response of ruminants. PMID:27288853

  9. A Diel Flux Balance Model Captures Interactions between Light and Dark Metabolism during Day-Night Cycles in C3 and Crassulacean Acid Metabolism Leaves1[C][W][OPEN

    PubMed Central

    Cheung, C.Y. Maurice; Poolman, Mark G.; Fell, David. A.; Ratcliffe, R. George; Sweetlove, Lee J.

    2014-01-01

    Although leaves have to accommodate markedly different metabolic flux patterns in the light and the dark, models of leaf metabolism based on flux-balance analysis (FBA) have so far been confined to consideration of the network under continuous light. An FBA framework is presented that solves the two phases of the diel cycle as a single optimization problem and, thus, provides a more representative model of leaf metabolism. The requirement to support continued export of sugar and amino acids from the leaf during the night and to meet overnight cellular maintenance costs forces the model to set aside stores of both carbon and nitrogen during the day. With only minimal constraints, the model successfully captures many of the known features of C3 leaf metabolism, including the recently discovered role of citrate synthesis and accumulation in the night as a precursor for the provision of carbon skeletons for amino acid synthesis during the day. The diel FBA model can be applied to other temporal separations, such as that which occurs in Crassulacean acid metabolism (CAM) photosynthesis, allowing a system-level analysis of the energetics of CAM. The diel model predicts that there is no overall energetic advantage to CAM, despite the potential for suppression of photorespiration through CO2 concentration. Moreover, any savings in enzyme machinery costs through suppression of photorespiration are likely to be offset by the higher flux demand of the CAM cycle. It is concluded that energetic or nitrogen use considerations are unlikely to be evolutionary drivers for CAM photosynthesis. PMID:24596328

  10. In vivo and in vitro microdialysis sampling of free fatty acids.

    PubMed

    Jensen, Signe Mølhøj; Hansen, Harald S; Johansen, Thue; Malmlöf, Kjell

    2007-04-11

    Microdialysis is a technique that allows continuous sampling of compounds from the interstitial fluid of different tissues with minimal influence on surrounding tissues and/or whole body function. In the present study, the feasibility of using microdialysis as a technique to sample free fatty acids (FFA) was investigated both in vitro and in vivo, by use of a high molecular weight (MW) cut-off membrane (3 MDa) and a push-pull system to avoid loss of perfusion fluid through the dialysis membrane. The relative recovery was examined in vitro for three different concentrations of radiolabelled oleic acid-BSA solutions (oleic acid:BSA molar ratio 1:1) and for various temperatures and flow rates. The recovery of oleic acid was found to be dependent on the concentration of analyte in the medium surrounding the membrane (17.3%, 29.0% and 30.6% for 50, 100 and 200 microM oleic acid-BSA solutions, respectively). Addition of 0.25% BSA to the perfusion fluid resulted, however, in a concentration-independent recovery of 31.4%, 28.1% and 28.1% for the 50, 100 and 200 microM solutions, respectively. The capability of the method to measure FFA together with glycerol was investigated in vivo in visceral adipose tissue of rats, before and after lipolytic treatment with the beta3-adrenergic agent, BRL37344. BRL37344 caused an increase in both dialysate FFA and glycerol, although the increase was markedly higher for glycerol, amounting to 24.5% and 329.2% increase from baseline, respectively. Subsequent in vitro test of probe performance revealed a decrease in the dialysing properties with regard to FFA, but not glycerol. This suggests that clogging of the membrane pores after 110 min prevented the measurement of the full FFA response in vivo. PMID:17240099

  11. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase.

    PubMed

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M; Brown, Robert J

    2014-09-01

    Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL. PMID:25130461

  12. Metabolic flux analysis of recombinant Pichia pastoris growing on different glycerol/methanol mixtures by iterative fitting of NMR-derived (13)C-labelling data from proteinogenic amino acids.

    PubMed

    Jordà, Joel; de Jesus, Sérgio S; Peltier, Solenne; Ferrer, Pau; Albiol, Joan

    2014-01-25

    The yeast Pichia pastoris has emerged as one of the most promising yeast cell factories for the production of heterologous proteins. The readily available genetic tools and the ease of high-cell density cultivations using methanol or glycerol/methanol mixtures are among the key factors for this development. Previous studies have shown that the use of mixed feeds of glycerol and methanol seem to alleviate the metabolic burden derived from protein production, allowing for higher specific and volumetric process productivities. However, initial studies of glycerol/methanol co-metabolism in P. pastoris by classical metabolic flux analyses using (13)C-derived Metabolic Flux Ratio (METAFoR) constraints were hampered by the reduced labelling information obtained when using C3:C1 substrate mixtures in relation to the conventional C6 substrate, that is, glucose. In this study, carbon flux distributions through the central metabolic pathways in glycerol/methanol co-assimilation conditions have been further characterised using biosynthetically directed fractional (13)C labelling. In particular, metabolic flux distributions were obtained under 3 different glycerol/methanol ratios and growth rates by iterative fitting of NMR-derived (13)C-labelling data from proteinogenic amino acids using the software tool (13)CFlux2. Specifically, cells were grown aerobically in chemostat cultures fed with 80:20, 60:40 and 40:60 (w:w) glycerol/methanol mixtures at two dilutions rates (0.05 hour(-1) and 0.16 hour(-1)), allowing to obtain additional data (biomass composition and extracellular fluxes) to complement pre-existing datasets. The performed (13)C-MFA reveals a significant redistribution of carbon fluxes in the central carbon metabolism as a result of the shift in the dilution rate, while the ratio of carbon sources has a lower impact on carbon flux distribution in cells growing at the same dilution rate. At low growth rate, the percentage of methanol directly dissimilated to CO2 ranges

  13. Non-equivalence of Key Positively Charged Residues of the Free Fatty Acid 2 Receptor in the Recognition and Function of Agonist Versus Antagonist Ligands*

    PubMed Central

    Sergeev, Eugenia; Hansen, Anders Højgaard; Pandey, Sunil K.; MacKenzie, Amanda E.; Hudson, Brian D.; Ulven, Trond; Milligan, Graeme

    2016-01-01

    Short chain fatty acids (SCFAs) are produced in the gut by bacterial fermentation of poorly digested carbohydrates. A key mediator of their actions is the G protein-coupled free fatty acid 2 (FFA2) receptor, and this has been suggested as a therapeutic target for the treatment of both metabolic and inflammatory diseases. However, a lack of understanding of the molecular determinants dictating how ligands bind to this receptor has hindered development. We have developed a novel radiolabeled FFA2 antagonist to probe ligand binding to FFA2, and in combination with mutagenesis and molecular modeling studies, we define how agonist and antagonist ligands interact with the receptor. Although both agonist and antagonist ligands contain negatively charged carboxylates that interact with two key positively charged arginine residues in transmembrane domains V and VII of FFA2, there are clear differences in how these interactions occur. Specifically, although agonists require interaction with both arginine residues to bind the receptor, antagonists require an interaction with only one of the two. Moreover, different chemical series of antagonist interact preferentially with different arginine residues. A homology model capable of rationalizing these observations was developed and provides a tool that will be invaluable for identifying improved FFA2 agonists and antagonists to further define function and therapeutic opportunities of this receptor. PMID:26518871

  14. Non-equivalence of Key Positively Charged Residues of the Free Fatty Acid 2 Receptor in the Recognition and Function of Agonist Versus Antagonist Ligands.

    PubMed

    Sergeev, Eugenia; Hansen, Anders Højgaard; Pandey, Sunil K; MacKenzie, Amanda E; Hudson, Brian D; Ulven, Trond; Milligan, Graeme

    2016-01-01

    Short chain fatty acids (SCFAs) are produced in the gut by bacterial fermentation of poorly digested carbohydrates. A key mediator of their actions is the G protein-coupled free fatty acid 2 (FFA2) receptor, and this has been suggested as a therapeutic target for the treatment of both metabolic and inflammatory diseases. However, a lack of understanding of the molecular determinants dictating how ligands bind to this receptor has hindered development. We have developed a novel radiolabeled FFA2 antagonist to probe ligand binding to FFA2, and in combination with mutagenesis and molecular modeling studies, we define how agonist and antagonist ligands interact with the receptor. Although both agonist and antagonist ligands contain negatively charged carboxylates that interact with two key positively charged arginine residues in transmembrane domains V and VII of FFA2, there are clear differences in how these interactions occur. Specifically, although agonists require interaction with both arginine residues to bind the receptor, antagonists require an interaction with only one of the two. Moreover, different chemical series of antagonist interact preferentially with different arginine residues. A homology model capable of rationalizing these observations was developed and provides a tool that will be invaluable for identifying improved FFA2 agonists and antagonists to further define function and therapeutic opportunities of this receptor. PMID:26518871

  15. Assessing the Accuracy and Precision of Inorganic Geochemical Data Produced through Flux Fusion and Acid Digestions: Multiple (60+) Comprehensive Analyses of BHVO-2 and the Development of Improved "Accepted" Values

    NASA Astrophysics Data System (ADS)

    Ireland, T. J.; Scudder, R.; Dunlea, A. G.; Anderson, C. H.; Murray, R. W.

    2014-12-01

    The use of geological standard reference materials (SRMs) to assess both the accuracy and the reproducibility of geochemical data is a vital consideration in determining the major and trace element abundances of geologic, oceanographic, and environmental samples. Calibration curves commonly are generated that are predicated on accurate analyses of these SRMs. As a means to verify the robustness of these calibration curves, a SRM can also be run as an unknown item (i.e., not included as a data point in the calibration). The experimentally derived composition of the SRM can thus be compared to the certified (or otherwise accepted) value. This comparison gives a direct measure of the accuracy of the method used. Similarly, if the same SRM is analyzed as an unknown over multiple analytical sessions, the external reproducibility of the method can be evaluated. Two common bulk digestion methods used in geochemical analysis are flux fusion and acid digestion. The flux fusion technique is excellent at ensuring complete digestion of a variety of sample types, is quick, and does not involve much use of hazardous acids. However, this technique is hampered by a high amount of total dissolved solids and may be accompanied by an increased analytical blank for certain trace elements. On the other hand, acid digestion (using a cocktail of concentrated nitric, hydrochloric and hydrofluoric acids) provides an exceptionally clean digestion with very low analytical blanks. However, this technique results in a loss of Si from the system and may compromise results for a few other elements (e.g., Ge). Our lab uses flux fusion for the determination of major elements and a few key trace elements by ICP-ES, while acid digestion is used for Ti and trace element analyses by ICP-MS. Here we present major and trace element data for BHVO-2, a frequently used SRM derived from a Hawaiian basalt, gathered over a period of over two years (30+ analyses by each technique). We show that both digestion

  16. Capillary electrophoresis of some free fatty acids using partially aqueous electrolyte systems and indirect UV detection. Application to the analysis of oleic and linoleic acids in peanut breeding lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study has shown for the first time the suitability of CE with a partially aqueous electrolyte system for the analysis of free fatty acids (FFA's) in small portions of single peanut seeds. The partially aqueous electrolyte system consisted of 40 mM Tris, 2.5 mM adenosine-5'-monophosphate (AMP) ...

  17. Increased lysine production by flux coupling of the tricarboxylic acid cycle and the lysine biosynthetic pathway--metabolic engineering of the availability of succinyl-CoA in Corynebacterium glutamicum.

    PubMed

    Kind, Stefanie; Becker, Judith; Wittmann, Christoph

    2013-01-01

    In this study, we demonstrate increased lysine production by flux coupling using the industrial work horse bacterium Corynebacterium glutamicum, which was mediated by the targeted interruption of the tricarboxylic acid (TCA) cycle at the level of succinyl-CoA synthetase. The succinylase branch of the lysine production pathway functions as the bridging reaction to convert succinyl-CoA to succinate in this aerobic bacterium. The mutant C. glutamicum ΔsucCD showed a 60% increase in the yield of lysine when compared to the advanced lysine producer which was used as parent strain. This mutant was highly vital and exhibited only a slightly reduced specific growth rate. Metabolic flux analysis with (13)C isotope studies confirmed that the increase in lysine production was mediated by pathway coupling. The novel strain exhibited an exceptional flux profile, which was closer to the optimum performance predicted by in silico pathway analysis than to the large set of lysine-producing strains analyzed thus far. Fluxomics and transcriptomics were applied as further targets for next-level strain engineering to identify the back-up mechanisms that were activated upon deletion of the enzyme in the mutant strain. It seemed likely that the cells partly recruited the glyoxylate shunt as a by-pass route. Additionally, the α-ketoglutarate decarboxylase pathway emerged as the potential compensation mechanism. This novel strategy appears equally promising for Escherichia coli, which is used in the industrial production of lysine, wherein this bacterium synthesizes lysine exclusively by succinyl-CoA activation of pathway intermediates. The channeling of a high flux pathway into a production pathway by pathway coupling is an interesting metabolic engineering strategy that can be explored to optimize bio-production in the future. PMID:22871505

  18. Driving carbon flux through exogenous butyryl-CoA: Acetate CoA-transferase to produce butyric acid at high titer in Thermobifida fusca.

    PubMed

    Deng, Yu; Mao, Yin; Zhang, Xiaojuan

    2015-12-20

    Butyric acid, a 4-carbon short chain fatty acid, is widely used in chemical, food, and pharmaceutical industries. The low activity of butyryl-CoA: acetate CoA-transferase in Thermobifida fusca muS, a thermophilic actinobacterium whose optimal temperature was 55°C, was found to hinder the accumulation of high yield of butyric acid. In order to solve this problem, an exogenous butyryl-CoA: acetate CoA-transferase gene (actA) from Thermoanaerobacterium thermosaccharolyticum DSM571 was integrated into the chromosome of T. fusca muS by replacing celR gene, forming T. fusca muS-1. We demonstrated that on 5g/L cellulose, the yield of butyric acid by the engineered muS-1 strain was increased by 42.9 % compared to the muS strain. On 100g/L of cellulose, the muS-1 strain could consume 90.5% of total cellulose in 144h, with 33.2g/L butyric acid produced. Furthermore, on the mix substrates including the major components of biomass: cellulose, xylose, mannose and galactose, 70.4g/L butyric acid was produced in 168h by fed-batch fermentation. To validate the ability of fermenting biomass, the muS-1 strain was grown on the milled corn stover ranging from 200 to 250μm. The muS-1 strain had the highest butyrate titer 17.1g/L on 90g/L corn stover. PMID:26535965

  19. Platelet-activating factor induces phospholipid turnover, calcium flux, arachidonic acid liberation, eicosanoid generation, and oncogene expression in a human B cell line

    SciTech Connect

    Schulam, P.G.; Kuruvilla, A.; Putcha, G.; Mangus, L.; Franklin-Johnson, J.; Shearer, W.T. )

    1991-03-01

    Platelet-activating factor is a potent mediator of the inflammatory response. Studies of the actions of platelet-activating factor have centered mainly around neutrophils, monocytes, and platelets. In this report we begin to uncover the influence of platelet-activating factor on B lymphocytes. Employing the EBV-transformed human B cell line SKW6.4, we demonstrate that platelet-activating factor significantly alters membrane phospholipid metabolism indicated by the incorporation of 32P into phosphatidylcholine, phosphatidylinositol, and phosphatidic acid but not significantly into phosphatidylethanolamine at concentrations ranging from 10(-9) to 10(-6) M. The inactive precursor, lyso-platelet-activating factor, at a concentration as high as 10(-7) M had no effect on any of the membrane phospholipids. We also show that platelet-activating factor from 10(-12) to 10(-6) M induced rapid and significant elevation in intracellular calcium levels, whereas lyso-platelet-activating factor was again ineffective. We further demonstrate the impact of platelet-activating factor binding to B cells by measuring platelet-activating factor induced arachidonic acid release and 5-hydroxyeicosatetraenoic acid production. Moreover, platelet-activating factor was capable of inducing transcription of the nuclear proto-oncogenes c-fos and c-jun. Finally we explored the possible role of 5-hydroxyeicosatetraenoic acid as a regulator of arachidonic acid liberation demonstrating that endogenous 5-lipoxygenase activity modulates platelet-activating factor induced arachidonic acid release perhaps acting at the level of phospholipase A2. In summary, platelet-activating factor is shown here to have a direct and profound effect on a pure B cell line.

  20. Low-quality vegetable oils as feedstock for biodiesel production using K-pumice as solid catalyst. Tolerance of water and free fatty acids contents.

    PubMed

    Díaz, L; Borges, M E

    2012-08-15

    Waste oils are a promising alternative feedstock for biodiesel production due to the decrease of the industrial production costs. However, feedstock with high free fatty acids (FFA) content presents several drawbacks when alkaline-catalyzed transesterification reaction is employed in biodiesel production process. Nowadays, to develop suitable processes capable of treating oils with high free fatty acids content, a two-step process for biodiesel production is being investigated. The major problem that it presents is that two catalysts are needed to carry out the whole process: an acidic catalyst for free fatty acids esterification (first step) and a basic catalyst for pretreated product transesterification (second step). The use of a bifunctional catalyst, which allows both reactions to take place simultaneously, could minimize the production costs and time. In the present study, the behavior of pumice, a natural volcanic material used as a heterogeneous catalyst, was tested using oils with several FFA and water contents as feedstock in the transesterification reaction to produce biodiesel. Pumice as a bifunctional solid catalyst, which can catalyze simultaneously the esterification of FFA and the transesterification of fatty acid glycerides into biodiesel, was shown to be an efficient catalyst for the conversion of low-grade, nonedible oil feedstock into biodiesel product. Using this solid catalyst for the transesterification reaction, high FAME yields were achieved when feedstock oils presented a FFA content until approximately 2% wt/wt and a water content until 2% wt/wt. PMID:22799882

  1. Net Flux of Amino Acids Across the Portal-drained Viscera and Liver of the Ewe During Abomasal Infusion of Protein and Glucose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Decreasing the fraction of amino acids metabolized by the mucosal cells may increase the fraction of AA being released into the blood. A potential mechanism to reduce AA catabolism by mucosal cells is to provide an alternative source of energy. We hypothesized that increasing glucose flow to the s...

  2. High-sucrose diet increases ROS generation, FFA accumulation, UCP2 level, and proton leak in liver mitochondria.

    PubMed

    Ruiz-Ramírez, Angélica; Chávez-Salgado, Monserrath; Peñeda-Flores, José Antonio; Zapata, Estrella; Masso, Felipe; El-Hafidi, Mohammed

    2011-12-01

    Obesity, a risk factor for insulin resistance, contributes to the development of type 2 diabetes and cardiovascular diseases. The relationship between increased levels of free fatty acids in the liver mitochondria, mitochondrial function, and ROS generation in rat model of obesity induced by a high-sucrose diet was not sufficiently established. We determined how the bioenergetic functions and ROS generation of the mitochondria respond to a hyperlipidemic environment. Mitochondria from sucrose-fed rats generated H(2)O(2) at a higher rate than the control mitochondria. Adding fatty acid-free bovine serum albumin to mitochondria from sucrose-fed rats significantly reduced the rate of H(2)O(2) generation. In contrast, adding exogenous oleic or linoleic acid exacerbated the rate of H(2)O(2) generation in both sucrose-fed and control mitochondria, and the mitochondria from sucrose-fed rats were more sensitive than the control mitochondria. The increased rate of H(2)O(2) generation in sucrose-fed mitochondria corresponded to decreased levels of reduced GSH and vitamin E and increased levels of Cu/Zn-SOD in the intermembrane space. There was no difference between the levels of lipid peroxidation and protein carbonylation in the two types of mitochondria. In addition to the normal activity of Mn-SOD, GPX and catalase detected an increased activity of complex II, and upregulation of UCP2 was observed in mitochondria from sucrose-fed rats, all of which may accelerate respiration rates and reduce generation of ROS. In turn, these effects may protect the mitochondria of sucrose-fed rats from oxidative stress and preserve their function and integrity. However, in whole liver these adaptive mechanisms of the mitochondria were inefficient at counteracting redox imbalances and inhibiting oxidative stress outside of the mitochondria. PMID:21917631

  3. Design, synthesis and Structure-activity relationship studies of new thiazole-based free fatty acid receptor 1 agonists for the treatment of type 2 diabetes.

    PubMed

    Li, Zheng; Qiu, Qianqian; Xu, Xue; Wang, Xuekun; Jiao, Lei; Su, Xin; Pan, Miaobo; Huang, Wenlong; Qian, Hai

    2016-05-01

    The free fatty acid receptor 1 (FFA1/GPR40) has attracted interest as a novel target for the treatment of type 2 diabetes. Several series of FFA1 agonists including TAK-875, the most advanced compound terminated in phase III studies due to concerns about liver toxicity, have been hampered by relatively high molecular weight and lipophilicity. Aiming to develop potent FFA1 agonists with low risk of liver toxicity by decreasing the lipophilicity, the middle phenyl of TAK-875 was replaced by 11 polar five-membered heteroaromatics. Subsequently, systematic exploration of SAR and application of molecular modeling, leads to the identification of compound 44, which was an excellent FFA1 agonist with robustly hypoglycemic effect both in normal and type 2 diabetic mice, low risks of hypoglycemia and liver toxicity even at the twice molar dose of TAK-875. Meanwhile, two important findings were noted. First, the methyl group in our thiazole series occupied a small hydrophobic subpocket which had no interactions with TAK-875. Furthermore, the agonistic activity revealed a good correlation with the dihedral angle between thiazole core and the terminal benzene ring. These results promote the understanding of ligand-binding pocket and might help to design more promising FFA1 agonists. PMID:26945112

  4. Surgical removal of visceral fat decreases plasma free fatty acid and increases insulin sensitivity on liver and peripheral tissue in monosodium glutamate (MSG)-obese rats.

    PubMed

    Kim, Y W; Kim, J Y; Lee, S K

    1999-10-01

    In order to evaluate the role of visceral and subcutaneous fat tissue in insulin sensitivity and lipid metabolism, we measured the fasting levels of plasma free fatty acid (FFA) and insulin, glucose disappearance rate (Rd), and hepatic glucose production rate (HGP) after surgical removal of visceral (VF) or subcutaneous (SF) fat tissue in monosodium glutamate-obese (MSG-Ob) rats. Monosodium glutamate obesity was induced in rats by neonatal injection of MSG. Surgery to remove fat was done at 15 weeks of age. The experiments were done four weeks after the surgery. MSG-Ob rats showed increased levels of FFA, insulin, and HGP and decreased Rd compared to normal rats. In the VF group, the FFA level and HGP were decreased to normal values, Rd was partially normalized, but the level of insulin did not change significantly compared to MSG-Ob. In the SF group, FFA and Rd were partially normalized, but HGP was not suppressed significantly compared to MSG-Ob. These results suggest that visceral fat affects the insulin sensitivity of liver and FFA concentration more than subcutaneous fat; however, no significant difference was shown on whole body insulin sensitivity and fasting insulin concentration. PMID:10576150

  5. Environment and phenology: CO2 net ecosystem exchange and CO2 flux partitioning at an acid and oligotrophic mire system in northern Sweden

    NASA Astrophysics Data System (ADS)

    Gažovič, Michal; Peichl, Matthias; Vermeij, Ilse; Limpens, Juul; Nilsson, Mats. B.

    2015-04-01

    Static chamber and environmental measurements in combination with vegetation indices (i.e. vascular green area (VGA) and the greenness chromatic color index (gcc) derived from digital camera images) were used to investigate effects of environment and phenology on the CO2 net ecosystem exchange (NEE) and CO2 flux partitioning at the Degerö Stormyr site in northern Sweden (64°11' 23.565" N, 19°33' 55.291 E) during two environmentally different years. Our measurement design included a control plot, a moss plot (where vascular plants were removed by clipping) and four heterotrophic respiration (RH) collars (where all green moss and vascular plant biomass were removed) to partition between soil heterotrophic and plant autotrophic (moss and vascular plants) respiration (RA), as well as between moss and vascular plant gross primary production (GPP). Environmental conditions, especially the shallow snow cover, peat soil frost and cold spring in 2014 caused delayed onset of spring green up, reduced soil respiration flux and reduced GPP of vascular plants. Soil temperature measured in 26 cm depth started to rise from spring temperatures of ~ 0.6 °C in 2013 and 0.15 °C in 2014 about 20 days earlier in 2013 compared to 2014. With earlier onset of the growing season and higher soil temperatures in 2013, heterotrophic soil respiration was higher in year 2013 than in year 2014. In 2013, RH dominated the total ecosystem respiration in all months but June and August. On contrary, autotrophic respiration dominated ecosystem respiration in all months of 2014. In both years, vascular plants and mosses were more or less equally contributing to autotrophic respiration. We measured higher GPP in year 2013 compared to year 2014. Also VGA and gcc were higher in spring and throughout the rest of 2013 compared to 2014. The onset of VGA was delayed by ~ 10 days in 2014. In general, total GPP was dominated by GPP of vascular plants in both years, although moss GPP had substantial

  6. Design, synthesis and structure-activity relationship studies of novel phenoxyacetamide-based free fatty acid receptor 1 agonists for the treatment of type 2 diabetes.

    PubMed

    Li, Zheng; Wang, Xuekun; Xu, Xue; Yang, Jianyong; Qiu, Qianqian; Qiang, Hao; Huang, Wenlong; Qian, Hai

    2015-10-15

    The free fatty acid receptor 1 (FFA1) has attracted extensive attention as a novel antidiabetic target in the last decade. Several FFA1 agonists reported in the literature have been suffered from relatively high molecular weight and lipophilicity. We have previously reported the FFA1 agonist 1. Based on the common amide structural characteristic of SAR1 and NIH screened compound, we here describe the continued structure-activity exploration to decrease the molecular weight and lipophilicity of the compound 1 series by converting various amide linkers. All of these efforts lead to the discovery of the preferable lead compound 18, a compound with considerable agonistic activity, high LE and LLE values, lower lipophilicity than previously reported agonists, and appreciable efficacy on glucose tolerance in both normal and type 2 diabetic mice. PMID:26420383

  7. Effect of somatic cell count in goat milk on yield, sensory quality and fatty acid profile of semi-hard cheese

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the effect of somatic cell count (SCC) of goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semi-hard cheese. Thirty kilograms of goat milk with mean SCC levels of 410,000 (Low), 770,000 (Medium), and 1,250,000 cells/mL (High) was obtained for the manu...

  8. Identification and Pharmacological Characterization of Multiple Allosteric Binding Sites on the Free Fatty Acid 1 Receptor

    PubMed Central

    Lin, Daniel C.-H.; Guo, Qi; Luo, Jian; Zhang, Jane; Nguyen, Kathy; Chen, Michael; Tran, Thanh; Dransfield, Paul J.; Brown, Sean P.; Houze, Jonathan; Vimolratana, Marc; Jiao, Xian Yun; Wang, Yingcai; Birdsall, Nigel J. M.

    2012-01-01

    Activation of FFA1 (GPR40), a member of G protein-coupling receptor family A, is mediated by medium- and long-chain fatty acids and leads to amplification of glucose-stimulated insulin secretion, suggesting a potential role for free fatty acid 1 (FFA1) as a target for type 2 diabetes. It was assumed previously that there is a single binding site for fatty acids and synthetic FFA1 agonists. However, using members of two chemical series of partial and full agonists that have been identified, radioligand binding interaction studies revealed that the full agonists do not bind to the same site as the partial agonists but exhibit positive heterotropic cooperativity. Analysis of functional data reveals positive functional cooperativity between the full agonists and partial agonists in various functional assays (in vitro and ex vivo) and also in vivo. Furthermore, the endogenous fatty acid docosahexaenoic acid (DHA) shows negative or neutral cooperativity with members of both series of agonists in binding assays but displays positive cooperativity in functional assays. Another synthetic agonist is allosteric with members of both agonist series, but apparently competitive with DHA. Therefore, there appear to be three allosterically linked binding sites on FFA1 with agonists specific for each of these sites. Activation of free fatty acid 1 receptor (FFAR1) by each of these agonists is differentially affected by mutations of two arginine residues, previously found to be important for FFAR1 binding and activation. These ligands with their high potencies and strong positive functional cooperativity with endogenous fatty acids, demonstrated in vitro and in vivo, have the potential to deliver therapeutic benefits. PMID:22859723

  9. Identification and pharmacological characterization of multiple allosteric binding sites on the free fatty acid 1 receptor.

    PubMed

    Lin, Daniel C-H; Guo, Qi; Luo, Jian; Zhang, Jane; Nguyen, Kathy; Chen, Michael; Tran, Thanh; Dransfield, Paul J; Brown, Sean P; Houze, Jonathan; Vimolratana, Marc; Jiao, Xian Yun; Wang, Yingcai; Birdsall, Nigel J M; Swaminath, Gayathri

    2012-11-01

    Activation of FFA1 (GPR40), a member of G protein-coupling receptor family A, is mediated by medium- and long-chain fatty acids and leads to amplification of glucose-stimulated insulin secretion, suggesting a potential role for free fatty acid 1 (FFA1) as a target for type 2 diabetes. It was assumed previously that there is a single binding site for fatty acids and synthetic FFA1 agonists. However, using members of two chemical series of partial and full agonists that have been identified, radioligand binding interaction studies revealed that the full agonists do not bind to the same site as the partial agonists but exhibit positive heterotropic cooperativity. Analysis of functional data reveals positive functional cooperativity between the full agonists and partial agonists in various functional assays (in vitro and ex vivo) and also in vivo. Furthermore, the endogenous fatty acid docosahexaenoic acid (DHA) shows negative or neutral cooperativity with members of both series of agonists in binding assays but displays positive cooperativity in functional assays. Another synthetic agonist is allosteric with members of both agonist series, but apparently competitive with DHA. Therefore, there appear to be three allosterically linked binding sites on FFA1 with agonists specific for each of these sites. Activation of free fatty acid 1 receptor (FFAR1) by each of these agonists is differentially affected by mutations of two arginine residues, previously found to be important for FFAR1 binding and activation. These ligands with their high potencies and strong positive functional cooperativity with endogenous fatty acids, demonstrated in vitro and in vivo, have the potential to deliver therapeutic benefits. PMID:22859723

  10. A panel of free fatty acid ratios to predict the development of metabolic abnormalities in healthy obese individuals

    PubMed Central

    Zhao, Linjing; Ni, Yan; Ma, Xiaojing; Zhao, Aihua; Bao, Yuqian; Liu, Jiajian; Chen, Tianlu; Xie, Guoxiang; Panee, Jun; Su, Mingming; Yu, Herbert; Wang, Congrong; Hu, Cheng; Jia, Weiping; Jia, Wei

    2016-01-01

    Increasing evidences support that metabolically healthy obese (MHO) is a transient state. However, little is known about the early markers associated with the development of metabolic abnormalities in MHO individuals. Serum free fatty acids (FFAs) profile is highlighted in its association with obesity-related insulin resistance, type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). To examine the association of endogenous fatty acid metabolism with future development of metabolic abnormalities in MHO individuals, we retrospectively analyzed 24 [product FFA]/[precursor FFA] ratios in fasting sera and clinical data from 481 individuals who participated in three independent studies, including 131 metabolic healthy subjects who completed the 10-year longitudinal Shanghai Diabetes Study (SHDS), 312 subjects cross-sectionally sampled from the Shanghai Obesity Study (SHOS), and 38 subjects who completed an 8-week very low carbohydrate diet (VLCD) intervention study. Results showed that higher baseline level of oleic acid/stearic acid (OA/SA), and lower levels of stearic acid/palmitic acid (SA/PA) and arachidonic acid/dihomo-γ-linolenic acid (AA/DGLA) ratios were associated with higher rate of MHO to MUO conversion in the longitudinal SHDS. Further, the finding was validated in the cross-sectional and interventional studies. This panel of FFA ratios could be used for identification and early intervention of at-risk obese individuals. PMID:27344992

  11. A panel of free fatty acid ratios to predict the development of metabolic abnormalities in healthy obese individuals.

    PubMed

    Zhao, Linjing; Ni, Yan; Ma, Xiaojing; Zhao, Aihua; Bao, Yuqian; Liu, Jiajian; Chen, Tianlu; Xie, Guoxiang; Panee, Jun; Su, Mingming; Yu, Herbert; Wang, Congrong; Hu, Cheng; Jia, Weiping; Jia, Wei

    2016-01-01

    Increasing evidences support that metabolically healthy obese (MHO) is a transient state. However, little is known about the early markers associated with the development of metabolic abnormalities in MHO individuals. Serum free fatty acids (FFAs) profile is highlighted in its association with obesity-related insulin resistance, type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). To examine the association of endogenous fatty acid metabolism with future development of metabolic abnormalities in MHO individuals, we retrospectively analyzed 24 [product FFA]/[precursor FFA] ratios in fasting sera and clinical data from 481 individuals who participated in three independent studies, including 131 metabolic healthy subjects who completed the 10-year longitudinal Shanghai Diabetes Study (SHDS), 312 subjects cross-sectionally sampled from the Shanghai Obesity Study (SHOS), and 38 subjects who completed an 8-week very low carbohydrate diet (VLCD) intervention study. Results showed that higher baseline level of oleic acid/stearic acid (OA/SA), and lower levels of stearic acid/palmitic acid (SA/PA) and arachidonic acid/dihomo-γ-linolenic acid (AA/DGLA) ratios were associated with higher rate of MHO to MUO conversion in the longitudinal SHDS. Further, the finding was validated in the cross-sectional and interventional studies. This panel of FFA ratios could be used for identification and early intervention of at-risk obese individuals. PMID:27344992

  12. Characterization of the esterification reaction in high free fatty acid oils

    NASA Astrophysics Data System (ADS)

    Altic, Lucas Eli Porter

    Energy and vegetable oil prices have caused many biodiesel producers to turn to waste cooking oils as feedstocks. These oils contain high levels of free fatty acids (FFAs) which make them difficult or impossible to convert to biodiesel by conventional production methods. Esterification is required for ultra-high FFA feedstocks such as Brown Grease. In addition, ultrasonic irradiation has the potential to improve the kinetics of the esterification reaction. 2-level, multi-factor DOE experiments were conducted to characterize the esterification reaction in ultra-high FFA oils as well as determine whether ultrasonic irradiation gives any benefit besides energy input. The study determined that sulfuric acid content had the greatest effect followed by temperature and water content (inhibited reaction). Methanol content had no effect in the range studied. A small interaction term existed between sulfuric acid and temperature. The study also concluded that sonication did not give any additional benefit over energy input.

  13. Bicellar systems as new delivery strategy for topical application of flufenamic acid.

    PubMed

    Rubio, L; Alonso, C; Rodríguez, G; Cócera, M; López-Iglesias, C; Coderch, L; De la Maza, A; Parra, J L; López, O

    2013-02-28

    In this work, bicellar systems, bilayered disc-shaped nanoaggregates formed in water by phospholipids, are proposed as a novel strategy for delivery of the anti-inflammatory flufenamic acid (FFA) to the skin. A comparative percutaneous penetration study of this drug in bicellar systems and other vehicles was conducted. The effects induced on the skin by the application of FFA in the different vehicles were analyzed by attenuated total reflectance-fourier transform infrared (ATR-FTIR). Additionally, using the microscopic technique freeze-substitution transmission electron microscopy (FSTEM) and X-ray scattering technique using synchrotron radiation (SAXS-SR), we studied the possible microstructural and organizational changes that were induced in the stratum corneum (SC) lipids and the collagen of the skin by the application of FFA bicellar systems. Bicellar systems exhibited a retarder effect on the percutaneous absorption of FFA with respect to the other vehicles without promoting disruption in the SC barrier function of the skin. Given that skin disruption is one of the main effects caused by inflammation, prevention of disruption and repair of the skin microstructure should be prioritized in anti-inflammatory formulations. PMID:23357252

  14. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture

    PubMed Central

    Kurt, Ramazan; Chandra, Partha K.; Aboulnasr, Fatma; Panigrahi, Rajesh; Ferraris, Pauline; Aydin, Yucel; Reiss, Krzysztof; Wu, Tong; Balart, Luis A.; Dash, Srikanta

    2015-01-01

    Background Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α)-based combination therapy in chronic hepatitis C virus (HCV) infection. Previously, we reported that free fatty acid (FFA)-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1), which is why the antiviral activity of IFN-α against HCV is impaired. Aim To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment. Method HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate) and unsaturated (oleate) long-chain free fatty acids (FFA). Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α) and Type III IFN (IFN-λ) was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA) in the FFA-treated HCV cell culture model was investigated. Results FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ), which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA

  15. Thermorecovery of cyanobacterial fatty acids at elevated temperatures.

    PubMed

    Liu, Xinyao; Curtiss, Roy

    2012-11-15

    We have developed a genetic system we call "thermorecovery" that allows us to lyse cyanobacterial cultures and hydrolyze membrane lipids to release free fatty acids (FFAs), a biofuel precursor. The system uses thermostable lipases encoded by genes from thermophilic organisms that have been transferred into the cyanobacterial genome and can be synthesized by turning off CO(2) availability and subsequently activated by increasing the concentrated culture temperature. When synthesized in FFA-producing strains, the lipase Fnl from Fervidobacterium nodosum Rt17-B1 released the most FFA. Of the seven candidate lipases investigated, Fnl-synthesizing strains yielded 42.7±1.5 mg/l FFA at 47°C. We also determined that the optimal production conditions for SD338, the Synechocystis strain synthesizing Fnl, was to keep the cell concentrates at 46°C for two days after a one-day CO(2) limitation pretreatment of the culture. A 4-l continuous semi-batch production experiment with SD338 showed that daily harvested cultures (1l) released an average of 43.9±6.6 mg fatty acid and this productivity lasted for at least 20 days without significant decline. This improved thermorecovery process can be used in conjunction with other means to genetically engineer cyanobacteria to produce biofuels or biofuel precursors as the final step in recovery of membrane lipids. PMID:22944207

  16. Methane flux from Minnesota peatlands

    SciTech Connect

    Crill, P.M.; Bartlett, K.B.; Harriss, R.C.; Gorham, E.; Verry, E.S. )

    1988-12-01

    Northern (> 40 deg N) wetlands have been suggested as the largest natural source of methane (CH{sub 4}) to the troposphere. To refine the authors estimates of source strengths from this region and to investigate climatic controls on the process, fluxes were measured from a variety of Minnesota peatlands during May, June, and August 1986. Late spring and summer fluxes ranged from 11 to 866 mg CH{sub 4}/sq/m/day, averaging 207 mg CH{sub 4} sq/m/day overall. At Marcell Forest, forested bogs and fen sites had lower fluxes than open bogs. In the Red Lake peatland, circumneutral fens, with standing water above the peat surface, produced more methane than acid bog sites in which the water table was beneath the moss surface. Peat temperature was an important control. Methane flux increased in response to increasing soil temperature. It is estimated that the methane flux from all peatlands north of 40 deg may be on the order of 70 to 90 Tg/yr though estimates of this sort are plagued by uncertainties in the areal extent of peatlands, length of the CH{sub 4} producing season, and the spatial and temporal variability of the flux. 60 refs., 7 figs., 5 tabs.

  17. Sex Differences in Long Chain Fatty Acid Utilization and Fatty Acid Binding Protein Concentration in Rat Liver

    PubMed Central

    Ockner, Robert K.; Burnett, David A.; Lysenko, Nina; Manning, Joan A.

    1979-01-01

    Female sex and estrogen administration are associated with increased hepatic production of triglyceride-rich lipoproteins; the basis for this has not been fully elucidated. Inasmuch as hepatic lipoprotein production is also influenced by FFA availability and triglyceride biosynthesis, we investigated sex differences in FFA utilization in rat hepatocyte suspensions and in the components of the triglyceride biosynthetic pathway. Isolated adult rat hepatocyte suspensions were incubated with albumin-bound [14C]oleate for up to 15 min. At physiological and low oleate concentrations, cells from females incorporated significantly more 14C into glycerolipids, especially triglycerides, and into oxidation products than did male cells, per milligram cell protein. At 0.44 mM oleate, incorporation into triglycerides in female cells was approximately twice that in male cells. Comparable sex differences were observed in cells from fasted animals and when [14C]-glycerol incorporation was measured. At higher oleate concentrations, i.e., fatty acid:albumin mole ratios in excess of 2:1, these sex differences were no longer demonstrable, suggesting that maximal rates of fatty acid esterification and oxidation were similar in female and male cells. In female and male hepatic microsomes, specific activities of long chain acyl coenzyme A synthetase, phosphatidate phosphohydrolase, and diglyceride acyltransferase were similar, but glycerol-3-phosphate acyltransferase activity was slightly greater in females at certain substrate concentrations. Microsomal incorporation of [14C]oleate into total glycerolipids was not significantly greater in females. In further contrast to intact cells, microsomal incorporation of [14C]oleate into triglycerides, although significantly greater in female microsomes, accounted for only a small fraction of the fatty acid esterified. The binding affinity and stoichiometry of partially purified female hepatic fatty acid binding protein (FABP) were similar to

  18. Fast flux locked loop

    DOEpatents

    Ganther, Jr., Kenneth R.; Snapp, Lowell D.

    2002-09-10

    A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

  19. Lack of excitatory amino acid-induced effects on calcium fluxes measured with sup 45 Ca sup 2+ in rat cerebral cortex synaptosomes

    SciTech Connect

    Simonato, M.; Jope, R.S.; Bianchi, C.; Beani, L. )

    1989-07-01

    Ca{sup 2+} uptake was measured in purified rat cerebral cortex synaptosomes (P3 pellets) using {sup 45}Ca{sup 2+} as a tracer. Ca{sup 2+} influx increased in time, and with an increase in external K+ concentration and temperature. The net (external K+-induced, depolarization-dependent) uptake follows a two-component course. The exponential term, due to the opening of voltage-operated calcium channels (VOC), has a rate constant which increases with an increase in the depolarization level (1.04 versus 0.54 nmol/s/mg protein for 50 mM - versus 15 mM (K+)-dependent net influx). The linear term, due to the Na{sup +}/Ca{sup 2+} exchange system, has a similar rate constant at all depolarization levels (0.16 +/- 0.05 and 0.11 +/- 0.02 nmol/s/mg protein). Excitatory amino acids (glutamate, kainate and n-methyl-d-aspartate-NMDA-) were tested on this preparation at doses ranging between 5 x 10(-5) M and 5 x 10(-3) M and at multiple incubation times, under resting conditions and under two depolarizing conditions (partial depolarization: 15 mM external K{sup +} and maximal depolarization: 50 mM external K+). NMDA was also tested in the absence of Mg{sup 2+}. No effect was detectable under any of these experimental conditions. Hypotheses to interpret these data are discussed. Further studies on other preparations are needed in order to directly investigate the presynaptic effects of excitatory amino acids.

  20. Microwave-assisted biodiesel production by esterification of palm fatty acid distillate.

    PubMed

    Lokman, Ibrahim M; Rashid, Umer; Zainal, Zulkarnain; Yunus, Robiah; Taufiq-Yap, Yun Hin

    2014-01-01

    In the current research work, effect of microwave irradiation energy on the esterification of palm fatty acid distillate (PFAD) to produce PFAD methyl ester / biodiesel was intensively appraised. The PFAD is a by-product from refinery of crude palm oil consisting >85% of free fatty acid (FFA). The esterification reaction process with acid catalyst is needed to convert the FFA into fatty acid methyl ester or known as biodiesel. In this work, fabricated microwave-pulse width modulation (MPWM) reactor with controlled temperature was designed to be capable to increase the PFAD biodiesel production rate. The classical optimization technique was used in order to study the relationship and the optimum condition of variables involved. Consequently, by using MPWM reactor, mixture of methanol-to-PFAD molar ratio of 9:1, 1 wt.% of sulfuric acid catalyst, at 55°C reaction temperature within 15 min reaction time gave 99.5% of FFA conversion. The quality assessment and properties of the product were analyzed according to the American Society for Testing and Materials (ASTM), European (EN) standard methods and all results were in agreement with the standard requirements. It revealed that the use of fabricated MPWM with controlled temperature was significantly affecting the rate of esterification reaction and also increased the production yield of PFAD methyl ester. PMID:25099911

  1. Bacterial production of free fatty acids from freshwater macroalgal cellulose

    PubMed Central

    Hoovers, Spencer W.; Marner, Wesley D.; Brownson, Amy K.; Lennen, Rebecca M.; Wittkopp, Tyler M.; Yoshitani, Jun; Zulkifly, Shahrizim; Graham, Linda E.; Chaston, Sheena D.; McMahon, Katherine D.

    2013-01-01

    The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing micro-organisms. Cellulose was extracted from an environmental sample of Cladophora glomerata-dominated periphyton that was collected from Lake Mendota, WI, USA. The resulting cellulose cake was hydrolyzed by commercial enzymes to release fermentable glucose. The hydrolysis mixture was used to formulate an undefined medium that was able to support the growth, without supplementation, of a free fatty acid (FFA)-overproducing strain of Escherichia coli (Lennen et. al 2010). To maximize free fatty acid production from glucose, an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible vector was constructed to express the Umbellularia californica acyl–acyl carrier protein (ACP) thioesterase. Thioesterase expression was optimized by inducing cultures with 50 μM IPTG. Cell density and FFA titers from cultures grown on algae-based media reached 50% of those (~90 μg/mL FFA) cultures grown on rich Luria–Bertani broth supplemented with 0.2% glucose. In comparison, cultures grown in two media based on AFEX-pretreated corn stover generated tenfold less FFA than cultures grown in algae-based media. This study demonstrates that macroalgal cellulose is a potential carbon source for the production of biofuels or other microbially synthesized compounds. PMID:21643704

  2. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

    SciTech Connect

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J.

    2014-09-05

    Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

  3. Understanding Particle Formation: Solubility of Free Fatty Acids as Polysorbate 20 Degradation Byproducts in Therapeutic Monoclonal Antibody Formulations.

    PubMed

    Doshi, Nidhi; Demeule, Barthélemy; Yadav, Sandeep

    2015-11-01

    The purpose of this work was to determine the aqueous solubilities at 2-8 °C of the major free fatty acids (FFAs) formed by polysorbate 20 (PS20) degradation and identify possible ways to predict, delay, or mitigate subsequent particle formation in monoclonal antibody (mAb) formulations. The FFA solubility limits at 2-8 °C were determined by titrating known amounts of FFA in monoclonal antibody formulations and identifying the FFA concentration leading to visible and subvisible particle formation. The solubility limits of lauric, myristic, and palmitic acids at 2-8 °C were 17 ± 1 μg/mL, 3 ± 1 μg/mL, and 1.5 ± 0.5 μg/mL in a formulation containing 0.04% (w/v) PS20 at pH 5.4 and >22 μg/mL, 3 ± 1 μg/mL, and 0.75 ± 0.25 μg/mL in a formulation containing 0.02% (w/v) PS20 at pH 6.0. For the first time, a 3D correlation between FFA solubility, PS20 concentration, and pH has been reported providing a rational approach for the formulator to balance these with regard to potential particle formation. The results suggest that the lower solubilities of the longer chain FFAs, generated from degradation of the stearate, palmitate, and myristate fraction of PS20, is the primary cause of seeding and subsequent FFA precipitation rather than the most abundant lauric acid. PMID:26419285

  4. Magnetic-flux pump

    NASA Technical Reports Server (NTRS)

    Hildebrandt, A. F.; Elleman, D. D.; Whitmore, F. C. (Inventor)

    1966-01-01

    A magnetic flux pump is described for increasing the intensity of a magnetic field by transferring flux from one location to the magnetic field. The device includes a pair of communicating cavities formed in a block of superconducting material, and a piston for displacing the trapped magnetic flux into the secondary cavity producing a field having an intense flux density.

  5. Effect of a sustained reduction in plasma free fatty acid concentration on insulin signalling and inflammation in skeletal muscle from human subjects

    PubMed Central

    Liang, Hanyu; Tantiwong, Puntip; Sriwijitkamol, Apiradee; Shanmugasundaram, Karthigayan; Mohan, Sumathy; Espinoza, Sara; DeFronzo, Ralph A; Dubé, John J; Musi, Nicolas

    2013-01-01

    Free fatty acids (FFAs) have been implicated in the pathogenesis of insulin resistance. Reducing plasma FFA concentration in obese and type 2 diabetic (T2DM) subjects improves insulin sensitivity. However, the molecular mechanism by which FFA reduction improves insulin sensitivity in human subjects is not fully understood. In the present study, we tested the hypothesis that pharmacological FFA reduction enhances insulin action by reducing local (muscle) inflammation, leading to improved insulin signalling. Insulin-stimulated total glucose disposal (TGD), plasma FFA species, muscle insulin signalling, IκBα protein, c-Jun phosphorylation, inflammatory gene (toll-like receptor 4 and monocyte chemotactic protein 1) expression, and ceramide and diacylglycerol (DAG) content were measured in muscle from a group of obese and T2DM subjects before and after administration of the antilipolytic drug acipimox for 7 days, and the results were compared to lean individuals. We found that obese and T2DM subjects had elevated saturated and unsaturated FFAs in plasma, and acipimox reduced all FFA species. Acipimox-induced reductions in plasma FFAs improved TGD and insulin signalling in obese and T2DM subjects. Acipimox increased IκBα protein (an indication of decreased IκB kinase–nuclear factor κB signalling) in both obese and T2DM subjects, but did not affect c-Jun phosphorylation in any group. Acipimox also decreased inflammatory gene expression, although this reduction only occurred in T2DM subjects. Ceramide and DAG content did not change. To summarize, pharmacological FFA reduction improves insulin signalling in muscle from insulin-resistant subjects. This beneficial effect on insulin action could be related to a decrease in local inflammation. Notably, the improvements in insulin action were more pronounced in T2DM, indicating that these subjects are more susceptible to the toxic effect of FFAs. PMID:23529132

  6. Membrane Stresses Induced by Overproduction of Free Fatty Acids in Escherichia coli.

    SciTech Connect

    Lennen, Rebecca M.; Kruziki, Max A.; Kumar, Kritika; Zinkel, Robert A.; Burnum, Kristin E.; Lipton, Mary S.; Hoover, Spencer W.; Ranatunga, Don Ruwan; Wittkopp, Tyler M.; Marner II, Wesley D.; Pfleger, Brian F.

    2011-11-01

    Microbially produced fatty acids are potential precursors to high energy density biofuels, including alkanes and alkyl ethyl esters by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversions of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs in Escherichia coli have achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain of E. coli that overproduces medium chain length FFAs was compared to an engineered control strain. By early stationary phase, an 85% reduction in viable cell counts and exacerbated loss of inner membrane integrity were observed in the FFA overproducing strain. These effects were enhanced in strains endogenously producing FFAs compared to strains exposed to exogenously fed FFAs. Under two sets of cultivation conditions, long chain unsaturated fatty acid content greatly increased and the expression of genes and proteins required for unsaturated fatty acid biosynthesis were significantly decreased. Membrane stresses were further implicated by increased expression of genes and proteins of the phage shock response, the MarA/Rob/SoxS regulon, and the nuo and cyo operons of aerobic respiration. Gene deletion studies confirmed the importance of the phage shock proteins and Rob for maintaining cell viability, however little to no change in FFA titers was observed after 24 h cultivation. The results of this study serve as a baseline for future targeted attempts to improve FFA yields and titers in E. coli.

  7. Drugs or diet? – Developing novel therapeutic strategies targeting the free fatty acid family of GPCRs

    PubMed Central

    Dranse, H J; Kelly, M E M; Hudson, B D

    2013-01-01

    Free fatty acids (FFAs) are metabolic intermediates that may be obtained through the diet, synthesized endogenously, or produced via fermentation of carbohydrates by gut microbiota. In addition to serving as an important source of energy, FFAs are known to produce a variety of both beneficial and detrimental effects on metabolic and inflammatory processes. While historically, FFAs were believed to produce these effects only through intracellular targets such as peroxisome proliferator-activated receptors, it has now become clear that FFAs are also agonists for several GPCRs, including a family of four receptors now termed FFA1-4. Increasing evidence suggests that FFA1-4 mediate many of the beneficial properties of FFAs and not surprisingly, this has generated significant interest in the potential of these receptors as therapeutic targets for the treatment of a variety of metabolic and inflammatory disorders. In addition to the traditional strategy of developing small-molecule therapeutics targeting these receptors, there has also been some consideration given to alternate therapeutic approaches, specifically by manipulating endogenous FFA concentrations through alteration of either dietary intake, or production by gut microbiota. In this review, the current state of knowledge for FFA1-4 will be discussed, together with their potential as therapeutic targets in the treatment of metabolic and inflammatory disorders. In particular, the evidence in support of small molecule versus dietary and microbiota-based therapeutic approaches will be considered to provide insight into the development of novel multifaceted strategies targeting the FFA receptors for the treatment of metabolic and inflammatory disorders. PMID:23937426

  8. Resveratrol prevents insulin resistance caused by short-term elevation of free fatty acids in vivo.

    PubMed

    Pereira, Sandra; Park, Edward; Moore, Jessy; Faubert, Brandon; Breen, Danna M; Oprescu, Andrei I; Nahle, Ashraf; Kwan, Denise; Giacca, Adria; Tsiani, Evangelia

    2015-11-01

    Elevated levels of plasma free fatty acids (FFA), which are commonly found in obesity, induce insulin resistance. FFA activate protein kinases including the proinflammatory IκBα kinase β (IKKβ), leading to serine phosphorylation of insulin receptor substrate 1 (IRS-1) and impaired insulin signaling. To test whether resveratrol, a polyphenol found in red wine, prevents FFA-induced insulin resistance, we used a hyperinsulinemic-euglycemic clamp with a tracer to assess hepatic and peripheral insulin sensitivity in overnight-fasted Wistar rats infused for 7 h with saline, Intralipid plus 20 U·mL(-1) heparin (IH; triglyceride emulsion that elevates FFA levels in vivo; 5.5 μL·min(-1)) with or without resveratrol (3 mg·kg(-1)·h(-1)), or resveratrol alone. Infusion of IH significantly decreased glucose infusion rate (GIR; P < 0.05) and peripheral glucose utilization (P < 0.05) and increased endogenous glucose production (EGP; P < 0.05) during the clamp compared with saline infusion. Resveratrol co-infusion, however, completely prevented the effects induced by IH infusion: it prevented the decreases in GIR (P < 0.05 vs. IH), peripheral glucose utilization (P < 0.05 vs. IH), and insulin-induced suppression of EGP (P < 0.05 vs. IH). Resveratrol alone had no effect. Furthermore, IH infusion increased serine (307) phosphorylation of IRS-1 in soleus muscle (∼30-fold, P < 0.001), decreased total IRS-1 levels, and decreased IκBα content, consistent with activation of IKKβ. Importantly, all of these effects were abolished by resveratrol (P < 0.05 vs. IH). These results suggest that resveratrol prevents FFA-induced hepatic and peripheral insulin resistance and, therefore, may help mitigate the health consequences of obesity. PMID:26455923

  9. Inflammation increases NOTCH1 activity via MMP9 and is counteracted by Eicosapentaenoic Acid-free fatty acid in colon cancer cells

    PubMed Central

    Fazio, Chiara; Piazzi, Giulia; Vitaglione, Paola; Fogliano, Vincenzo; Munarini, Alessandra; Prossomariti, Anna; Milazzo, Maddalena; D’Angelo, Leonarda; Napolitano, Manuela; Chieco, Pasquale; Belluzzi, Andrea; Bazzoli, Franco; Ricciardiello, Luigi

    2016-01-01

    Aberrant NOTCH1 signalling is critically involved in multiple models of colorectal cancer (CRC) and a prominent role of NOTCH1 activity during inflammation has emerged. Epithelial to Mesenchymal Transition (EMT), a crucial event promoting malignant transformation, is regulated by inflammation and Metalloproteinase-9 (MMP9) plays an important role in this process. Eicosapentaenoic Acid (EPA), an omega-3 polyunsaturated fatty acid, was shown to prevent colonic tumors in different settings. We recently found that an extra-pure formulation of EPA as Free Fatty Acid (EPA-FFA) protects from colon cancer development in a mouse model of Colitis-Associated Cancer (CAC) through modulation of NOTCH1 signalling. In this study, we exposed colon cancer cells to an inflammatory stimulus represented by a cytokine-enriched Conditioned Medium (CM), obtained from THP1-differentiated macrophages. We found, for the first time, that CM strongly up-regulated NOTCH1 signalling and EMT markers, leading to increased invasiveness. Importantly, NOTCH1 signalling was dependent on MMP9 activity, upon CM exposure. We show that a non-cytotoxic pre-treatment with EPA-FFA antagonizes the effect of inflammation on NOTCH1 signalling, with reduction of MMP9 activity and invasiveness. In conclusion, our data suggest that, in CRC cells, inflammation induces NOTCH1 activity through MMP9 up-regulation and that this mechanism can be counteracted by EPA-FFA. PMID:26864323

  10. Theme: Impact of FFA Leadership.

    ERIC Educational Resources Information Center

    Gartin, Stacy A.; And Others

    1991-01-01

    Seven articles in this theme issue discuss how to enhance leadership skills through mentoring, the pitfalls of leadership education, teachers' role, leadership for handicapped learners, and the impact of Future Farmers of America on development of student leaders. (SK)

  11. Validation of a new method for determination of free fatty acid turnover

    SciTech Connect

    Miles, J.M.; Ellman, M.G.; McClean, K.L.; Jensen, M.D.

    1987-03-01

    The accuracy of tracer methods for estimating free fatty acid (FFA) rate of appearance (Ra), either under steady-state conditions or under non-steady-state conditions, has not been previously investigated. In the present study, endogenous lipolysis (traced with /sup 14/C palmitate) was suppressed in six mongrel dogs with a high-carbohydrate meal 10 h before the experiment, together with infusions of glucose, propranolol, and nicotinic acid during the experimental period. Both steady-state and non-steady-state equations were used to determine oleate Ra ((/sup 3/H)oleate) before, during, and after a stepwise infusion of an oleic acid emulsion. Palmitate Ra did not change during the experiment. Steady-state equations gave the best estimates of oleate inflow approximately 93% of the known oleate infusion rate overall, while errors in tracer estimates of inflow were obtained when non-steady-state equations were used. The metabolic clearance rate of oleate was inversely related to plasma concentration (P less than 0.01). In conclusion, accurate estimates of FFA inflow were obtained when steady-state equations were used, even under conditions of abrupt and recent changes in Ra. Non-steady-state equations, in contrast, may provide erroneous estimates of inflow. The decrease in metabolic clearance rate during exogenous infusion of oleate suggests that FFA transport may follow second-order kinetics.

  12. Simultaneous determination of rosuvastatin and fenofibric acid in human plasma by LC-MS/MS with electrospray ionization: assay development, validation and application to a clinical study.

    PubMed

    Trivedi, Ravi Kumar; Kallem, Raja Reddy; Mullangi, Ramesh; Srinivas, Nuggehally R

    2005-09-15

    A simple, sensitive and specific LC-MS/MS method for simultaneous determination of rosuvastatin (RST) and fenofibric acid (FFA) was developed and validated with 500 microL human plasma using carbamazepine as an internal standard (IS). The assay procedure involved a simple one-step liquid/liquid extraction of RST and FFA and IS from plasma into ethyl acetate. The organic layer was separated and evaporated under a gentle stream of nitrogen at 40 degrees C. The residue was reconstituted in the mobile phase and injected onto X-Terra MS C-18 column (4.6 mm x 50 mm, 5.0 microm). Separation of RST, FFA and IS was achieved with a mobile phase consisting of 0.05 M formic acid:acetonitrile (45:55, v/v) at a flow rate of 0.40 ml/min. The API-3000LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique. Positive ion acquisition chromatographic run was used in the present method. Nominal retention times of RST, FFA and IS were 2.35, 4.70 and 2.32 min, respectively. Absolute recovery of RST, FFA and IS was 74, 61 and 69%, respectively. The lower limit of quantification (LLOQ) of RST and FFA was 1.00 ng/ml and 0.50 microg/ml, respectively. Response function was established for the range of concentrations 1.00-50.0 ng/ml and 0.50-20.0 microg/ml for RST and FFA, respectively, with a coefficient of determination (r2) of 0.999 for both the compounds. The inter- and intra-day precision in the measurement of RST quality control (QC) samples 5, 15, 400 and 800 ng/ml, were in the range 8.93-9.37% relative standard deviation (R.S.D.) and 1.74-16.1% R.S.D., respectively. Similarly, the inter- and intra-day precision in the measurement of FFA quality control (QC) samples 0.5, 1.5, 8.0 and 15.0 microg/ml, were in the range 9.78-11.6% relative standard deviation (R.S.D.) and 0.22-17.4% R.S.D., respectively. Accuracy in the measurement of QC samples for RST and FFA were in the range 88.1-108 and 87-115%, respectively, of the nominal

  13. Ethanesulfonic acid-based esterification of industrial acidic crude palm oil for biodiesel production.

    PubMed

    Hayyan, Adeeb; Mjalli, Farouq S; Hashim, Mohd Ali; Hayyan, Maan; AlNashef, Inas M; Al-Zahrani, Saeed M; Al-Saadi, Mohammed A

    2011-10-01

    An industrial grade acidic crude palm oil (ACPO) pre-treatment process was carried out using ethanesulfonic acid (ESA) as a catalyst in the esterification reaction. ESA was used in different dosages to reduce free fatty acid (FFA) to a minimum level for the second stage of biodiesel production via alkaline transesterification reaction. Different process operating conditions were optimized such as ESA dosage (0.25-3.5% wt/wt), methanol to ACPO molar ratio (1:1-20:1), reaction temperature (40-70 °C), and reaction time (3-150 min). This study revealed the potential use of abundant quantities of ACPO from oil palm mills for biodiesel production. The lab scale results showed the effectiveness of the pre-treatment process using ESA catalyst. Three consecutive catalyst recycling runs were achieved without significant degradation in its performance. Second and third reuse runs needed more reaction time to achieve the target level of FFA content. Esterification and transesterification using ESA and KOH respectively is proposed for biodiesel industrial scale production. The produced biodiesel meets the international standards specifications for biodiesel fuel (EN 14214 and ASTM D6751). PMID:21855329

  14. The influence of free fatty acids on glycogen recovery in rat heart after exercise.

    PubMed

    Conlee, R K; Dalsky, G P; Robinson, K C

    1981-01-01

    Glycogen supercompensation is the term used to denote the abnormally high levels of glycogen found in the heart shortly after an exercise-induced reduction of the substrate. Using rats, we tested whether this condition was linked to the use of plasma free fatty acids (FFA), which normally rise with exercise. Before a 1-h swim, animals received an injection of either saline (S) or nicotinic acid (NA). The nicotinic acid treatment dramatically suppressed the rise in plasma FFA observed in the S-group. Exercise caused a significant but similar reduction (35-38%) of the myocardial glycogen content in both groups. After 1 h of recovery in the S-group, myocardial glycogen reached a value of 30.3 +/- 1.7 mumol x g-1 or 113% of that measured before the exercise began. In contrast, the value for hearts from the NA-group with reduced FFA levels was 24.0 +/- 1.9 mumol x g-1 or only 91% of that measured before exercise. After 2 h the values were 33.8 +/- 1.4 and 29.0 +/- 1.9 mumol x g-1 respectively. These data indicate that glycogen repletion in rat heart after exercise is related to the amount of FFA present in the plasma. We suggest that carbohydrate metabolism is diverted towards synthesis and storage as a result of the glycolytic inhibition exerted by the increased use of fat as an energy source as previously observed in hearts from fasted or diabetic animals. PMID:7199440

  15. Uncoupling of fatty acid and glucose metabolism in malignant lymphoma: a PET study.

    PubMed

    Nuutinen, J; Minn, H; Bergman, J; Haaparanta, M; Ruotasalainen, U; Laine, H; Knuuti, J

    1999-05-01

    Increased use of glucose through glycolysis is characteristic for neoplastic growth while the significance of serum-free fatty acids for regulation of energy metabolism in cancer is poorly understood. We studied whether serum-free fatty acids (FFA) interfere with glycolytic metabolism of lymphoproliferative neoplasms as assessed with 2-F18-fluoro-2-deoxy-D-glucose ([F18]FDG) and positron emission tomography (PET). Twelve patients with newly diagnosed non-Hodgkin's lymphoma (n = 9) or Hodgkin's disease (n = 3) participated in this study before start of oncologic treatment. Each patient underwent two [F18]FDG PET studies within 1 week after overnight fast: once during high fasting serum FFA concentrations and once after reduction of serum FFA by administration of acipimox. Acipimox is a nicotinic acid derivative that inhibits lipolysis in peripheral tissues and induces a striking reduction in circulating FFA concentration. In all cases, dynamic PET imaging over the tumour area was performed for 60 min after injection of [F18]FDG. Both graphical analysis (rMR(FDG)) and single scan approach (SUV) were used to compare tumour uptake of [F18]FDG under high fasting FFA concentrations and after pharmacologically decreased FFA concentrations. Serum FFA concentrations were reduced significantly from 0.92+/-0.42 mmol I(-1)at baseline to 0.26+/-0.31 mmol I(-1) after acipimox administration (P = 0.0003). Plasma glucose, serum insulin and lactate concentrations were similar during both approaches. The retention of glucose analogue [F18]FDG in tumour was similar between baseline and acipimox studies. Median rMR(FDG) of a total of 12 involved lymph nodes in 12 patients was 21.9 micromol 100 g(-1) min(-1) (range 8.7-82.5) at baseline and 20.1 micromol 100 g(-1) min(-1)(range 10.7-81.7) after acipimox. The respective values for median SUV were 7.8 (range 3.6-18.6) and 6.0 (range 4.1-20.2). As expected, [F18]FDG uptake in myocardium was clearly enhanced by acipimox due to reduction of

  16. A combination of eicosapentaenoic acid-free fatty acid, epigallocatechin-3-gallate and proanthocyanidins has a strong effect on mTOR signaling in colorectal cancer cells.

    PubMed

    D'Angelo, Leonarda; Piazzi, Giulia; Pacilli, Annalisa; Prossomariti, Anna; Fazio, Chiara; Montanaro, Lorenzo; Graziani, Giulia; Fogliano, Vincenzo; Munarini, Alessandra; Bianchi, Francesca; Belluzzi, Andrea; Bazzoli, Franco; Ricciardiello, Luigi

    2014-10-01

    Colorectal cancer (CRC) is one of the major causes of cancer death worldwide. The development of novel anti-CRC agents able to overcome drug resistance and/or off-target toxicity is of pivotal importance. The mammalian target of rapamycin (mTOR) plays a critical role in CRC, regulating protein translation and controlling cell growth, proliferation, metabolism and survival. The aim of this study was to explore the effect of a combination of three natural compounds, eicosapentaenoic acid-free fatty acid (EPA-FFA), epigallocatechin-3-gallate (EGCG) and proanthocyanidins (grape seed [GS] extract) at low cytotoxic concentrations on CRC cells and test their activity on mTOR and translational regulation. The CRC cell lines HCT116 and SW480 were treated for 24h with combinations of EPA-FFA (0-150 µM), EGCG (0-175 µM) and GS extract (0-15 µM) to evaluate the effect on cell viability. The low cytotoxic combination of EPA-FFA 150 µM, EGCG 175 µM and GS extract 15 µM completely inhibited the mTOR signaling in HCT116 and SW480 cells, reaching an effect stronger than or comparable to that of the mTOR inhibitor Rapamycin in HCT116 or SW480 cells, respectively. Moreover, the treatment led to changes of protein translation of ribosomal proteins, c-Myc and cyclin D1. In addition, we found a reduction of clonal capability in both cell lines, with block of cell cycle in G0G1 and induction of apoptosis. Our data suggest that the low cytotoxic combination of EPA-FFA, EGCG and GS extract, tested for the first time here, inhibits mTOR signaling and thus could be considered for CRC treatment. PMID:25123131

  17. Preparation of biodiesel from rice bran fatty acids catalyzed by heterogeneous cesium-exchanged 12-tungstophosphoric acids.

    PubMed

    Srilatha, K; Sree, Rekha; Prabhavathi Devi, B L A; Sai Prasad, P S; Prasad, R B N; Lingaiah, N

    2012-07-01

    Biodiesel synthesis from rice bran fatty acids (RBFA) was carried out using cesium exchanged 12-tungstophosphoric acid (TPA) catalysts. The physico-chemical properties of the catalysts were derived from X-ray diffraction (XRD), Fourier transform infrared (FTIR), temperature programmed desorption (TPD) of NH(3) and scanning electron microscopy (SEM). The characterization techniques revealed that the Keggin structure of TPA remained intact as Cs replaced protons. The partial exchange of Cs for protons resulted in an increase in acidity and the catalysts with one Cs(+) (Cs(1)H(2)PW(12)O(40)) showed highest acidity. Under optimized conditions about 92% conversion of RBFA was obtained. The catalyst was reused for five times and retained of its original activity. Pseudo-first order model was applied to correlate the experimental kinetic data. Modified tungstophosphoric acids are efficient solid acid catalysts for the synthesis of biodiesel from the oils containing high FFA. PMID:22609655

  18. Kinetic study on microwave-assisted esterification of free fatty acids derived from Ceiba pentandra Seed Oil.

    PubMed

    Lieu, Thanh; Yusup, Suzana; Moniruzzaman, Muhammad

    2016-07-01

    Recently, a great attention has been paid to advanced microwave technology that can be used to markedly enhance the biodiesel production process. Ceiba pentandra Seed Oil containing high free fatty acids (FFA) was utilized as a non-edible feedstock for biodiesel production. Microwave-assisted esterification pretreatment was conducted to reduce the FFA content for promoting a high-quality product in the next step. At optimum condition, the conversion was achieved 94.43% using 2wt% of sulfuric acid as catalyst where as 20.83% conversion was attained without catalyst. The kinetics of this esterification reaction was also studied to determine the influence of factors on the rate of reaction and reaction mechanisms. The results indicated that microwave-assisted esterification was of endothermic second-order reaction with the activation energy of 53.717kJ/mol. PMID:27019128

  19. Silica-bonded N-propyl sulfamic acid used as a heterogeneous catalyst for transesterification of soybean oil with methanol.

    PubMed

    Xie, Wenlei; Yang, Dong

    2011-10-01

    The transesterification of soybean oil with methanol was carried out, to produce biodiesel, over silica-bonded N-propyl sulfamic acid in a heterogeneous manner. Results showed that a maximum conversion of 90.5% was achieved using a 1:20 M ratio of soybean oil to methanol and a catalyst amount of 7.5 wt.% at 423 K for 60 h. It was found that the free fatty acid (FFA) and water present in the feedstock had no significant influence on the catalytic activity to the transesterification reaction. Besides, the catalyst also showed activities towards the esterification reaction of FFAs, in terms of the FFA conversion of 95.6% at 423 K for 30 h. Furthermore, the catalyst could be recovered with a better reusability. PMID:21871795

  20. Broad-range TRP channel inhibitors (2-APB, flufenamic acid, SKF-96365) affect differently contraction of resistance and conduit femoral arteries of rat.

    PubMed

    Bencze, Michal; Behuliak, Michal; Vavřínová, Anna; Zicha, Josef

    2015-10-15

    Transient receptor potential (TRP) channels are proposed to contribute to membrane depolarization and Ca2+ influx into vascular smooth muscle (VSM) cells. Our aim was to study the effects of widely used broad-range TRP channel inhibitors--2-aminoethoxydiphenyl borate (2-APB), flufenamic acid (FFA) and SKF-96365--on the contraction of freshly isolated small and large arteries. Endothelium-denuded resistance (≈250 µm) and conduit (≈1000 µm) femoral arteries were isolated from adult Wistar rats and mounted in wire myograph. The effects of the above mentioned TRP channel inhibitors and voltage-dependent calcium channel inhibitor nifedipine were studied on arterial contractions induced by phenylephrine, U-46619 or K+. Phenylephrine-induced contractions were also studied in the absence of extracellular Na+. mRNA expression of particular canonical and melastatin TRP channel subunits in femoral vascular bed was determined. TRP channel inhibitors attenuated K+-induced contraction less than nifedipine. Phenylephrine-induced contraction was more influenced by 2-APB in resistance arteries, while FFA completely prevented U-46619-induced contraction in both sizes of arteries. The absence of extracellular Na+ prevented the inhibitory effects of 2-APB, but not those of FFA. The observed effects of broad-range TRP channel inhibitors, which were dependent on the size of the artery, confirmed the involvement of TRP channels in agonist-induced contractions. The inhibitory effects of 2-APB (but not those of FFA or SKF-96365) were dependent on the presence of extracellular Na+. PMID:26384458

  1. Hydrolysis optimization and characterization study of preparing fatty acids from Jatropha curcas seed oil

    PubMed Central

    2011-01-01

    Background Fatty acids (FAs) are important as raw materials for the biotechnology industry. Existing methods of FAs production are based on chemical methods. In this study potassium hydroxide (KOH)-catalyzed reactions were utilized to hydrolysis Jatropha curcas seed oil. Results The parameters effect of ethanolic KOH concentration, reaction temperature, and reaction time to free fatty acid (FFA%) were investigated using D-Optimal Design. Characterization of the product has been studied using Fourier transforms infrared spectroscopy (FTIR), gas chromatography (GC) and high performance liquid chromatography (HPLC). The optimum conditions for maximum FFA% were achieved at 1.75M of ethanolic KOH concentration, 65°C of reaction temperature and 2.0 h of reaction time. Conclusions This study showed that ethanolic KOH concentration was significant variable for J. curcas seed oil hydrolysis. In a 18-point experimental design, FFA% of hydrolyzed J. curcas seed oil can be raised from 1.89% to 102.2%, which proved by FTIR and HPLC. PMID:22044685

  2. Effect of fatty acids on lipid and apoprotein secretion and association in hepatocyte cultures.

    PubMed Central

    Patsch, W; Tamai, T; Schonfeld, G

    1983-01-01

    Increasing availability of free fatty acids (FFA) to liver results in enhanced rates of secretion of triglycerides in lipoproteins. However, as FFA uptake increases, triglyceride secretory rates reach a plateau and esterified fatty acids accumulate intracellularly, suggesting that something is limiting lipid transport out of the liver. One possibility could be the limited availability of apoproteins. To test this hypothesis, primary rat hepatocytes in culture were incubated with increasing amounts of FFA (0-2.1 mumol/dish) and the amounts of lipids and apoproteins inside the cells and in culture media were measured; the latter by specific radioimmunoassays. Media also were fractionated on Sepharose 2B and 6B columns and the elution profiles of apoproteins were obtained. With exposure to increasing amounts of free fatty acids, hepatocytes took up more fatty acids and intracellular levels of triglycerides rose (from 71 to 146 micrograms/mg cell protein). Concomitantly, media triglycerides nearly doubled (31 to 51 micrograms/mg). Incorporation of [3H]glyceride into cellular and media triglyceride also rose. However, levels of apoproteins A-I, B, C-III3, and E in cells and media were unchanged. The increasing amounts of triglycerides in media were present in larger particles, as demonstrated on gel permeation chromatography. The elution profiles of apoproteins B, C-III3, and E were altered in that a greater proportion of the apoproteins eluted with larger particles. Similar results were obtained when hepatocytes were preloaded with increasing amounts of FFA over 12 h and analyses of cells and media were carried out 8 and 22 h after removal of fatty acids from the media. During loading of cells, accumulation of cellular triglycerides was directly related to media FFA concentrations. During unloading, triglyceride secretory rates were related to cellular triglyceride levels. At higher triglyceride secretory rates larger particles were secreted and a greater proportion of

  3. Determination of Free Fatty Acids and Triglycerides by Gas Chromatography Using Selective Esterification Reactions

    SciTech Connect

    Kail, Brian W; Link, Dirk D; Morreale, Bryan D

    2012-11-01

    A method for selectively determining both free fatty acids (FFA) and triacylglycerides (TAGs) in biological oils was investigated and optimized using gas chromatography after esterification of the target species to their corresponding fatty acid methyl esters (FAMEs). The method used acid catalyzed esterification in methanolic solutions under conditions of varying severity to achieve complete conversion of more reactive FFAs while preserving the concentration of TAGs. Complete conversion of both free acids and glycerides to corresponding FAMEs was found to require more rigorous reaction conditions involving heating to 120°C for up to 2 h. Method validation was provided using gas chromatography–flame ionization detection, gas chromatography–mass spectrometry, and liquid chromatography–mass spectrometry. The method improves on existing methods because it allows the total esterified lipid to be broken down by FAMEs contributed by FFA compared to FAMEs from both FFA and TAGs. Single and mixed-component solutions of pure fatty acids and triglycerides, as well as a sesame oil sample to simulate a complex biological oil, were used to optimize the methodologies. Key parameters that were investigated included: HCl-to-oil ratio, temperature and reaction time. Pure free fatty acids were found to esterify under reasonably mild conditions (10 min at 50°C with a 2.1:1 HCl to fatty acid ratio) with 97.6 ± 2.3% recovery as FAMEs, while triglycerides were largely unaffected under these reaction conditions. The optimized protocol demonstrated that it is possible to use esterification reactions to selectively determine the free acid content, total lipid content, and hence, glyceride content in biological oils. This protocol also allows gas chromatography analysis of FAMEs as a more ideal analyte than glyceride species in their native state.

  4. Clinical significance of elevated serum A-FABP and free fatty acid in neonates with hypoxic ischemic brain damage

    PubMed Central

    Li, Mei; Jiang, Lian; Zhang, Huifen; Wang, Dandan; Zhang, Min; Zhang, Lianshan

    2016-01-01

    The main function of adipocyte fatty acid-binding protein (A-FABP) is to regulate fatty acid metabolism as its molecular chaperone. The clinical significance of A-FABP in hypoxic-ischemic brain damage (HIBD) neonates is not yet clear. Free fatty acid (FFA) in cerebral cortex increases along with hypoxia ischemia degree. Thus, we aimed to investigate whether FFA can induce A-FABP expression and elevate the serum A-FABP level in HIBD neonates. In the present study, 42 HIBD neonates were selected including 11 cases as mild, 16 cases as moderate and 15 cases as severe. The serum was collected from peripheral vein at 72 h after the first visit (acute stage) and 7 days after birth (recovery stage), and the serum from 10 normal neonates was used as the control. The serum level of A-FABP and FFA in 42 neonates with acute phase and recovery phase HIBD were detected using ELISA and copper colorimetric method. The overall serum A-FABP content in HIBD neonates at the acute stage was significantly higher compared to the normal neonates (P<0.05). The serum A-FABP level in severe HIBD neonates was significantly higher than that in mild HIBD, moderate HIBD and normal neonates (P<0.05). The serum FFA level in HIBD neonates at the acute stage was 1,521.57±605.63 µmol/l, which was significantly higher than that in the normal neonates 838.24±294.22 µmol/l. The serum FFA levels in mild, moderate and severe HIBD neonates were significantly higher than those in the normal neonates. The overall A-FABP level in HIBD neonates at the recovery stage was significantly lower compared to the acute stage, which was significant in severe HIBD neonates. A-FABP levels in mild and moderate HIBD neonates at recovery stage were decreased compared with the acute stage, although there was no statistical difference. There was a positive correlation between serum A-FABP and FFA in HIBD neonates at acute stage (r=0.369, P<0.05). In conclusion, serum A-FABP and FFA levels were signifcantly increased in

  5. Return flux experiment

    NASA Technical Reports Server (NTRS)

    Tveekrem, June L.

    1992-01-01

    All spacecraft emit molecules via outgassing, thruster plumes, vents, etc. The return flux is the portion of those molecules that scatter from the ambient atmosphere and return to the spacecraft. Return flux allows critical spacecraft surfaces to become contaminated even when there is no direct line of sight between the contamination source and the critical surface. Data from the Long Duration Exposure Facility (LDEF) show that contamination of LDEF surfaces could not have come entirely from direct flux. The data suggest significant return flux. Several computer models have been developed to simulate return flux, but the predictions have never been verified in orbit. Large uncertainties in predictions lead to overly conservative spacecraft designs. The purpose of the REturn FLux EXperiment (REFLEX) is to fly a controlled experiment that can be directly compared with predictions from several models.

  6. Interaction of free fatty acids with mitochondria: coupling, uncoupling and permeability transition.

    PubMed

    Di Paola, Marco; Lorusso, Michele

    2006-01-01

    Long chain free fatty acids (FFA) exert, according to their actual concentration, different effects on the energy conserving system of mitochondria. Sub-micromolar concentrations of arachidonic acid (AA) rescue DeltapH-dependent depression of the proton pumping activity of the bc1 complex. This effect appears to be due to a direct interaction of AA with the proton-input mouth of the pump. At micromolar concentrations FFA increase the proton conductance of the inner membrane acting as protonophores. FFA can act as natural uncouplers, causing a mild uncoupling, which prevents reactive oxygen species production in the respiratory resting state. When Ca(2+)-loaded mitochondria are exposed to micromolar concentrations of FFA, the permeability of the inner membrane increases, resulting in matrix swelling, rupture of the outer membrane and release of intermembrane pro-apoptotic proteins. The characteristics of AA-induced swelling appear markedly different in mitochondria isolated from heart or liver. While in the latter it presents the canonical features of the classical permeability transition (PT), in heart mitochondria substantial differences are observed concerning CsA sensitivity, DeltaPsi dependence, reversibility by BSA and specificity for the activating divalent cation. In heart mitochondria, the AA-dependent increase of the inner membrane permeability is affected by ANT ligands such as adenine nucleotides and atractyloside. AA apparently causes a Ca2+-mediated conversion of ANT from a translocator to a channel system. Upon diamide treatment of heart mitochondria, the Ca2+/AA-induced CsA insensitive channel is converted into the classical PT pore. The relevance of these observations in terms of tissue-specific components of the putative PTP and heart ischemic and post-ischemic process is discussed. PMID:16697347

  7. Conjugated Linoleic Triacylglycerols Exhibit Superior Lymphatic Absorption Than Free Conjugate Linoleic Acids and Have Antiobesity Properties.

    PubMed

    Woo, Hyunjoon; Chung, Min-Yu; Kim, Juyeon; Kong, Daecheol; Min, Jinyoung; Choi, Hee-Don; Choi, In-Wook; Kim, In-Hwan; Noh, Sang K; Kim, Byung Hee

    2016-05-01

    This study aimed to compare lymphatic absorption of conjugated linoleic acids (CLAs) in the triacylglycerol (TAG) or free fatty acid (FFA) form and to examine the antiobesity effects of different doses of CLAs in the TAG form in animals. Conjugated linoleic TAGs (containing 70.3 wt% CLAs; CLA-TAG) were prepared through lipase-catalyzed esterification of glycerol with commercial CLA mixtures (CLA-FFA). Lymphatic absorption of CLA-TAG and CLA-FFA was compared in a rat model of lymphatic cannulation. Greater amounts of cis-9,trans-11 and trans-10,cis-12 CLAs were detected in the collected lymph from a lipid emulsion containing CLA-TAG. This result suggests that CLA-TAG has greater capacity for lymphatic absorption than does CLA-FFA. The antiobesity efficacy of CLA-TAG at different doses was examined in mice with diet-induced obesity. A high-fat diet (HFD) for 12 weeks caused a significant increase in body weight and epididymal and retroperitoneal fat weights, which were significantly decreased by 2% dietary supplementation (w/w) with CLA-TAG. CLA-TAG at 2% significantly attenuated the HFD-induced upregulation of serum TAG, but led to hepatomegaly and exacerbated HFD-induced hypercholesterolemia. CLA-TAG at 1% significantly attenuated upregulation of retroperitoneal fat weight and significantly increased liver weight, which was decreased by the HFD. Nonetheless, the liver weight in group "HFD +1% CLA-TAG" was not significantly different from that of normal diet controls. CLA-TAG at 1% significantly reduced serum TAG levels and did not exacerbate HFD-induced hypercholesterolemia. Thus, 1% dietary supplementation with CLA-TAG reduces retroperitoneal fat weight without apparent hepatomegaly, a known side-effect of CLAs in mouse models of obesity. PMID:27081749

  8. Identification of a Cyanobacterial RND-Type Efflux System Involved in Export of Free Fatty Acids.

    PubMed

    Kato, Akihiro; Takatani, Nobuyuki; Use, Kazuhide; Uesaka, Kazuma; Ikeda, Kazutaka; Chang, Yajun; Kojima, Kouji; Aichi, Makiko; Ihara, Kunio; Nakahigashi, Kenji; Maeda, Shin-Ichi; Omata, Tatsuo

    2015-12-01

    An RND (resistance-nodulation-division)-type transporter having the capacity to export free fatty acids (FFAs) was identified in the cyanobacterium Synechococcus elongatus strain PCC 7942 during characterization of a mutant strain engineered to produce FFAs. The basic strategy for construction of the FFA-producing mutant was a commonly used one, involving inactivation of the endogenous acyl-acyl carrier protein synthetase gene (aas) and introduction of a foreign thioesterase gene ('tesA), but a nitrate transport mutant NA3 was used as the parental strain to achieve slow, nitrate-limited growth in batch cultures. Also, a nitrogen-regulated promoter PnirA was used to drive 'tesA to maximize thioesterase expression during the nitrate-limited growth. The resulting mutant (dAS2T) was, however, incapable of growth under the conditions of nitrate limitation, presumably due to toxicity associated with FFA overproduction. Incubation of the mutant culture under the non-permissive conditions allowed for isolation of a pseudorevertant (dAS2T-pr1) capable of growth on nitrate. Genome sequence and gene expression analyses of this strain suggested that expression of an RND-type efflux system had rescued growth on nitrate. Targeted inactivation of the RND-type transporter genes in the wild-type strain resulted in loss of tolerance to exogenously added FFAs including capric, lauric, myristic, oleic and linolenic acids. Overexpression of the genes in dAS2T, on the other hand, enhanced FFA excretion and cell growth in nitrate-containing medium, verifying that the genes encode an efflux pump for FFAs. These results demonstrate the importance of the efflux system in efficient FFA production using genetically engineered cyanobacteria. PMID:26468506

  9. Heat flux measurements

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1989-01-01

    A new automated, computer controlled heat flux measurement facility is described. Continuous transient and steady-state surface heat flux values varying from about 0.3 to 6 MW/sq m over a temperature range of 100 to 1200 K can be obtained in the facility. An application of this facility is the development of heat flux gauges for continuous fast transient surface heat flux measurement on turbine blades operating in space shuttle main engine turbopumps. The facility is useful for durability testing at fast temperature transients.

  10. Aspects of flux compactification

    NASA Astrophysics Data System (ADS)

    Liu, Tao

    In this thesis, we study three main aspects of flux compactifications: (1) classify supergravity solutions from flux compactification; (2) construct flux-deformed geometry and 4D low-energy theory to describe these flux vacua; and (3) study 4D particle phenomenology and cosmology of flux vacua. In the first part, we review G-structure, the basic tool to study supersymmetric flux solutions, and some typical solutions obtained in heterotic, type IIA and type IIB string theories. Then we present a comprehensive classification of supersymmetric vacua of M-theory compactification on 7D manifolds with general four-form fluxes. We analyze the cases where the resulting four-dimensional vacua have N = 1, 2, 3, 4 supersymmetry and the internal space allows for SU(2)-, SU(3)- or G 2-structures. In particular, we find for N = 2 supersymmetry, that the external space-time is Minkowski and the base manifold of the internal space is conformally Kahler for SU(2) structures, while for SU(3) structures the internal space has to be Einstein-Sasaki and no internal fluxes are allowed. Moreover, we provide a new vacuum with N = 1 supersymmetry and SU(3) structure, where all fluxes are non-zero and the first order differential equations are solved. In the second part, we simply review the methods used to construct one subclass of fluxed-deformed geometry or the so-called "twisted manifold", and the associated 4D effective theory describing these flux vacua. Then by employing (generalized) Scherk-Schwarz reduction, we construct the geometric twisting for Calabi-Yau manifolds of Voisin-Borcea type (K 3 x T2)/ Z2 and study the superpotential in a type IIA orientifold based on this geometry. The twists modify the direct product by fibering the K 3 over T2 while preserving the Z2 involution. As an important application, the Voisin-Borcea class contains T6/( Z2 x Z2 ), the usual setting for intersecting D6 brane model building. Past work in this context considered only those twists inherited

  11. Inhibitory effect of schisandrin B on free fatty acid-induced steatosis in L-02 cells

    PubMed Central

    Chu, Jian-Hong; Wang, Hui; Ye, Yan; Chan, Ping-Kei; Pan, Si-Yuan; Fong, Wang-Fun; Yu, Zhi-Ling

    2011-01-01

    AIM: To investigate the effects of schisandrin B (Sch B) on free fatty acid (FFA)-induced steatosis in L-02 cells. METHODS: Cellular steatosis was induced by incubating L-02 cells with a FFA mixture (oleate and palmitate at the ratio of 2:1) for 24 h. Cytotoxicity and apoptosis were evaluated by 3-(4, 5-dmethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay and Annexin V/propidium iodide staining, respectively. Cellular total lipid was determined using a photocolorimetric method after Nile red staining, and triglyceride content was measured using an enzymatic kit. To study the effects of Sch B on steatosis, L-02 cells were treated with Sch B (1-100 μmol/L) in the absence or presence of 1 mmol/L FFA for 24 h, and cellular total lipid and triglyceride levels were measured. To explore the mechanisms of action of Sch B in the steatotic L-02 cells, mRNA levels of several regulators of hepatic lipid metabolism including adipose differentiation related protein (ADRP), sterol regulatory element binding protein 1 (SREBP-1), peroxisome proliferator-activated receptor (PPAR)-α and PPAR-γ were measured by quantitative real-time polymerase chain reaction (PCR), and protein levels of ADRP and SREBP-1 were measured by immunoblotting. RESULTS: Treatment with 1 mmol/L FFA for 24 h induced intracellular lipid accumulation in L-02 cells comparable to that in human steatotic livers without causing apparent apoptosis and cytotoxicity. Sch B mitigated cellular total lipid and triglyceride accumulations in the steatotic L-02 cells in a dose-dependent manner. Quantitative real-time PCR and Western blot analyses revealed that treatment of L-02 cells with 100 μmol/L Sch B reverted the FFA-stimulated up-regulation of ADRP and SREBP-1. CONCLUSION: Sch B inhibits FFA-induced steatosis in L-02 cells by, at least in part, reversing the up-regulation of ADRP and SREBP-1. PMID:21633637

  12. Video Meteor Fluxes

    NASA Technical Reports Server (NTRS)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  13. LCLS Spectral Flux Viewer

    2005-10-25

    This application (FluxViewer) is a tool for displaying spectral flux data for the Linac Coherent Light Source (LCLS). This tool allows the user to view sliced spatial and energy distributions of the photons selected for specific energies and positions transverse to the beam axis.

  14. Identification of molecular species of simple lipids by normal phase liquid chromatography-positive electrospray tandem mass spectrometry, and application of developed methods in comprehensive analysis of low erucic acid rapeseed oil lipids

    NASA Astrophysics Data System (ADS)

    Kalo, P. J.; Ollilainen, V.; Rocha, J. M.; Malcata, F. X.

    2006-07-01

    Mono-, di- and triacylglycerol (MAG, DAG, TAG), sterol ester (SE), free sterol (S) and free fatty acid (FFA) standards were analyzed in the presence of ammonium ions and ammonia by flow injection MS2 and MS3, and by normal phase-liquid chromatography (NP-LC) MS2 positive electrospray ionization (ESI) mass spectrometry (MS). The MS data recorded for ammonium adducts ([M + NH4]+) of TAGs, DAGs, and MAGs were consistent with stepwise fragmentation mechanisms. In the first step, ammonium ion in [M + NH4]+ donates proton to acylglycerol and ammonia is released. In the second step, FFA is cleaved from protonated TAG, water from protonated 1,3-DAG and MAG, both FFA and water from protonated 1,2-DAG, hence leading to formation of [DAG]+ ion from TAG and 1,3-DAG, [DAG]+ and [MAG]+ ions from 1,2-DAG, and [MAG]+ ion from MAG. In the third step, [DAG]+ ion of TAG is fragmented to yield [Acyl]+, [Acyl + 74]+, [DAG - 74]+ ions, [DAG] ion of 1,3-DAG to [Acyl]+ ions, and [MAG]+ ion of MAG to protonated FAs, which are decomposed to water and [Acyl]+ ions in the fourth step. A stepwise mechanism for fragmentation of FFA was also evident from MS2 and MS3 data. Molecular species of low erucic acid rapeseed oil simple lipids were identified from characteristic ions produced in the NP-LC-ESI-MS2 of [M + NH4]+ ions. The percentage composition of the molecular species of each lipid class was calculated from integrated extracted ion chromatograms of [(M + NH4)]+ ions of SE, TAG, MAG, and FFA, of the sum of [(M + NH4)]+ and [(M + NH4) - NH3 - H2O]+ ions of both regioisomers of DAGs, and of sterol fragment ions of S.

  15. Directed flux motor

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  16. Heat Flux Sensor

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A heat flux microsensor developed under a NASP Small Business Innovation Research (SBIR) has a wide range of potential commercial applications. Vatell Corporation originally designed microsensors for use in very high temperatures. The company then used the technology to develop heat flux sensors to measure the rate of heat energy flowing in and out of a surface as well as readings on the surface temperature. Additional major advantages include response to heat flux in less than 10 microseconds and the ability to withstand temperatures up to 1,200 degrees centigrade. Commercial applications are used in high speed aerodynamics, supersonic combustion, blade cooling, and mass flow measurements, etc.

  17. Noninvasive Measurement of Plasma Triglycerides and Free Fatty Acids from Exhaled Breath

    PubMed Central

    Minh, Timothy Do Chau; Oliver, Stacy R; Flores, Rebecca L; Ngo, Jerry; Meinardi, Simone; Carlson, Matthew K; Midyett, Jason; Rowland, F Sherwood; Blake, Donald R; Galassetti, Pietro Renato

    2012-01-01

    Background Although altered metabolism has long been known to affect human breath, generating clinically usable metabolic tests from exhaled compounds has proven challenging. If developed, a breath-based lipid test would greatly simplify management of diabetes and serious pathological conditions (e.g., obesity, familial hyperlipidemia, and coronary artery disease), in which systemic lipid levels are a critical risk factor for onset and development of future cardiovascular events. Methods We, therefore, induced controlled fluctuations of plasma lipids (insulin-induced lipid suppression or intravenous infusion of Intralipid) during 4-h in vivo experiments on 23 healthy volunteers (12 males/11 females, 28.0 ± 0.3 years) to find correlations between exhaled volatile organic compounds and plasma lipids. In each subject, plasma triglycerides (TG) and free fatty acids (FFA) concentrations were both directly measured and calculated via individualized prediction equations based on the multiple linear regression analysis of a cluster of 4 gases. In the lipid infusion protocol, we also generated common prediction equations using a maximum of 10 gases. Results This analysis yielded strong correlations between measured and predicted values during both lipid suppression (r = 0.97 for TG; r = 0.90 for FFA) and lipid infusion (r = 0.97 for TG; r = 0.94 for FFA) studies. In our most accurate common prediction model, measured and predicted TG and FFA values also displayed very strong statistical agreement (r = 0.86 and r = 0.81, respectively). Conclusions Our results demonstrate the feasibility of measuring plasma lipids through breath analysis. Optimization of this technology may ultimately lead to the development of portable breath analyzers for plasma lipids, replacing blood-based bioassays. PMID:22401327

  18. Cryogenic flux-concentrator

    NASA Technical Reports Server (NTRS)

    Bailey, B. M.; Brechna, H.; Hill, D. A.

    1969-01-01

    Flux concentrator has high primary to secondary coupling efficiency enabling it to produce high magnetic fields. The device provides versatility in pulse duration, magnetic field strengths and power sources.

  19. SAMOS Surface Fluxes

    NASA Astrophysics Data System (ADS)

    Smith, Shawn; Bourassa, Mark

    2014-05-01

    The development of a new surface flux dataset based on underway meteorological observations from research vessels will be presented. The research vessel data center at the Florida State University routinely acquires, quality controls, and distributes underway surface meteorological and oceanographic observations from over 30 oceanographic vessels. These activities are coordinated by the Shipboard Automated Meteorological and Oceanographic System (SAMOS) initiative in partnership with the Rolling Deck to Repository (R2R) project. Recently, the SAMOS data center has used these underway observations to produce bulk flux estimates for each vessel along individual cruise tracks. A description of this new flux product, along with the underlying data quality control procedures applied to SAMOS observations, will be provided. Research vessels provide underway observations at high-temporal frequency (1 min. sampling interval) that include navigational (position, course, heading, and speed), meteorological (air temperature, humidity, wind, surface pressure, radiation, rainfall), and oceanographic (surface sea temperature and salinity) samples. Vessels recruited to the SAMOS initiative collect a high concentration of data within the U.S. continental shelf and also frequently operate well outside routine shipping lanes, capturing observations in extreme ocean environments (Southern, Arctic, South Atlantic, and South Pacific oceans). These observations are atypical for their spatial and temporal sampling, making them very useful for many applications including validation of numerical models and satellite retrievals, as well as local assessments of natural variability. Individual SAMOS observations undergo routine automated quality control and select vessels receive detailed visual data quality inspection. The result is a quality-flagged data set that is ideal for calculating turbulent flux estimates. We will describe the bulk flux algorithms that have been applied to the

  20. Algebraic Flux Correction II

    NASA Astrophysics Data System (ADS)

    Kuzmin, Dmitri; Möller, Matthias; Gurris, Marcel

    Flux limiting for hyperbolic systems requires a careful generalization of the design principles and algorithms introduced in the context of scalar conservation laws. In this chapter, we develop FCT-like algebraic flux correction schemes for the Euler equations of gas dynamics. In particular, we discuss the construction of artificial viscosity operators, the choice of variables to be limited, and the transformation of antidiffusive fluxes. An a posteriori control mechanism is implemented to make the limiter failsafe. The numerical treatment of initial and boundary conditions is discussed in some detail. The initialization is performed using an FCT-constrained L 2 projection. The characteristic boundary conditions are imposed in a weak sense, and an approximate Riemann solver is used to evaluate the fluxes on the boundary. We also present an unconditionally stable semi-implicit time-stepping scheme and an iterative solver for the fully discrete problem. The results of a numerical study indicate that the nonlinearity and non-differentiability of the flux limiter do not inhibit steady state convergence even in the case of strongly varying Mach numbers. Moreover, the convergence rates improve as the pseudo-time step is increased.

  1. Membrane Stresses Induced by Overproduction of Free Fatty Acids in Escherichia coli▿†

    PubMed Central

    Lennen, Rebecca M.; Kruziki, Max A.; Kumar, Kritika; Zinkel, Robert A.; Burnum, Kristin E.; Lipton, Mary S.; Hoover, Spencer W.; Ranatunga, Don R.; Wittkopp, Tyler M.; Marner, Wesley D.; Pfleger, Brian F.

    2011-01-01

    Microbially produced fatty acids are potential precursors to high-energy-density biofuels, including alkanes and alkyl ethyl esters, by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversion of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs in Escherichia coli have achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain of E. coli that overproduces medium-chain-length FFAs was compared to an engineered control strain. By early stationary phase, an 85% reduction in viable cell counts and exacerbated loss of inner membrane integrity were observed in the FFA-overproducing strain. These effects were enhanced in strains endogenously producing FFAs compared to strains exposed to exogenously fed FFAs. Under two sets of cultivation conditions, long-chain unsaturated fatty acid content greatly increased, and the expression of genes and proteins required for unsaturated fatty acid biosynthesis were significantly decreased. Membrane stresses were further implicated by increased expression of genes and proteins of the phage shock response, the MarA/Rob/SoxS regulon, and the nuo and cyo operons of aerobic respiration. Gene deletion studies confirmed the importance of the phage shock proteins and Rob for maintaining cell viability; however, little to no change in FFA titer was observed after 24 h of cultivation. The results of this study serve as a baseline for future targeted attempts to improve FFA yields and titers in E. coli. PMID:21948837

  2. Magnetic flux tube tunneling

    SciTech Connect

    Dahlburg, R.B.; Antiochos, S.K.; Norton, D.

    1997-08-01

    We present numerical simulations of the collision and subsequent interaction of {ital orthogonal} magnetic flux tubes. The simulations were carried out using a parallelized spectral algorithm for compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the flux tubes can {open_quotes}tunnel{close_quotes} through each other, a behavior not previously seen in studies of either vortex tube or magnetic flux tube interactions. Two conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch {gt}1, and the Lundquist number must be somewhat large, {ge}2880. An examination of magnetic field lines suggests that tunneling is due to a double-reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections, and {open_quotes}pass{close_quotes} through each other. The implications of these results for solar and space plasmas are discussed. {copyright} {ital 1997} {ital The American Physical Society}

  3. Superradiance and flux conservation

    NASA Astrophysics Data System (ADS)

    Boonserm, Petarpa; Ngampitipan, Tritos; Visser, Matt

    2014-09-01

    The theoretical foundations of the phenomenon known as superradiance still continue to attract considerable attention. Despite many valiant attempts at pedagogically clear presentations, the effect nevertheless still continues to generate some significant confusion. Part of the confusion arises from the fact that superradiance in a quantum field theory context is not the same as superradiance (superfluorescence) in some condensed matter contexts; part of the confusion arises from traditional but sometimes awkward normalization conventions, and part is due to sometimes unnecessary confusion between fluxes and probabilities. We shall argue that the key point underlying the effect is flux conservation (and, in the presence of dissipation, a controlled amount of flux nonconservation), and that attempting to phrase things in terms of reflection and transmission probabilities only works in the absence of superradiance. To help clarify the situation we present a simple exactly solvable toy model exhibiting both superradiance and damping.

  4. Magnetic flux tube tunneling

    NASA Astrophysics Data System (ADS)

    Dahlburg, R. B.; Antiochos, S. K.; Norton, D.

    1997-08-01

    We present numerical simulations of the collision and subsequent interaction of orthogonal magnetic flux tubes. The simulations were carried out using a parallelized spectral algorithm for compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the flux tubes can ``tunnel'' through each other, a behavior not previously seen in studies of either vortex tube or magnetic flux tube interactions. Two conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch >>1, and the Lundquist number must be somewhat large, >=2880. An examination of magnetic field lines suggests that tunneling is due to a double-reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections, and ``pass'' through each other. The implications of these results for solar and space plasmas are discussed.

  5. Protected Flux Pairing Qubit

    NASA Astrophysics Data System (ADS)

    Bell, Matthew; Zhang, Wenyuan; Ioffe, Lev; Gershenson, Michael

    2014-03-01

    We have studied the coherent flux tunneling in a qubit containing two submicron Josephson junctions shunted by a superinductor (a dissipationless inductor with an impedance much greater than the resistance quantum). The two low energy quantum states of this device, 0 and 1, are represented by even and odd number of fluxes in the loop, respectively. This device is dual to the charge pairing Josephson rhombi qubit. The spectrum of the device, studied by microwave spectroscopy, reflects the interference between coherent quantum phase slips in the two junctions (the Aharonov-Casher effect). The time domain measurements demonstrate the suppression of the qubit's energy relaxation in the protected regime, which illustrates the potential of this flux pairing device as a protected quantum circuit. Templeton Foundation, NSF, and ARO.

  6. Determination of free fatty acids in beer.

    PubMed

    Bravi, Elisabetta; Marconi, Ombretta; Sileoni, Valeria; Perretti, Giuseppe

    2017-01-15

    Free fatty acids (FFA) content of beer affects the ability to form a stable head of foam and plays an important role in beer staling. Moreover, the presence of saturated FAs is related sometimes to gushing problems in beer. The aim of this research was to validate an analytical method for the determination of FFAs in beer. The extraction of FFAs in beer was achieved via Liquid-Liquid Cartridge Extraction (LLCE), the FFAs extract was purified by Solid Phase Extraction (SPE), methylated by boron trifluoride in methanol, and injected into GC-FID system. The performance criteria demonstrate that this method is suitable for the analysis of medium and long chain FFAs in beer. The proposed method was tested on four experimental beers. PMID:27542484

  7. Overexpression of variant PNPLA3 gene at I148M position causes malignant transformation of hepatocytes via IL-6-JAK2/STAT3 pathway in low dose free fatty acid exposure: a laboratory investigation in vitro and in vivo.

    PubMed

    Liu, Zhengtao; Chen, Tianchi; Lu, Xiaoxiao; Xie, Haiyang; Zhou, Lin; Zheng, Shusen

    2016-01-01

    Epidemiological survey identified that the variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene at I148M position exerts direct effect in promoting hepatocellular carcinoma (HCC) under extraneous oxidative stress by interaction with obesity. However, the mechanism is still unknown. HepG2 cells were overexpressed by transinfection of PNPLA3 with wild-type 148I (PNPLA3(WT)) and mutant 148M (PNPLA3(I148M)), respectively. Variation in metabolic indicators, hepatic steatosis, biological behaviors and signaling molecules related to cancer promotion was measured in hepatocytes using low-dose free fatty acid (FFA) exposure. Effect of PNPLA3(I148M) on xenograft biology and its interaction with dietary obesity were also evaluated in animal study. Cells overexpresssing PNPLA3(I148M) in low-dose FFA incubation showed more proliferation, migration, invasion, and less apoptosis (P<0.05). Low-dose FFA specifically activated JAK2/STAT3 phosphorylation of PNPLA3(I148M) cells via upregulation of interleukin-6. Animal study showed high-fat diet accelerated growth of xenografts derived from PNPLA3(I148M) cells incubated in low-dose FFA. In low oxidative stress, PNPLA3(I148M) initiated the hepatocyte malignant transformation through the activation of inflammation-mediated JAK/STAT pathway. Dietary obesity amplified the growth of tumor from PNPLA3(I148M) cells by interaction with local FFA incubation. Anti-inflammation and weight loss might be potential approaches for preventing HCC in high-risk population carrying PNPLA3 variant. PMID:27186262

  8. Overexpression of variant PNPLA3 gene at I148M position causes malignant transformation of hepatocytes via IL-6-JAK2/STAT3 pathway in low dose free fatty acid exposure: a laboratory investigation in vitro and in vivo

    PubMed Central

    Liu, Zhengtao; Chen, Tianchi; Lu, Xiaoxiao; Xie, Haiyang; Zhou, Lin; Zheng, Shusen

    2016-01-01

    Epidemiological survey identified that the variant patatin-like phospholipase domain-containing protein 3 (PNPLA3) gene at I148M position exerts direct effect in promoting hepatocellular carcinoma (HCC) under extraneous oxidative stress by interaction with obesity. However, the mechanism is still unknown. HepG2 cells were overexpressed by transinfection of PNPLA3 with wild-type 148I (PNPLA3WT) and mutant 148M (PNPLA3I148M), respectively. Variation in metabolic indicators, hepatic steatosis, biological behaviors and signaling molecules related to cancer promotion was measured in hepatocytes using low-dose free fatty acid (FFA) exposure. Effect of PNPLA3I148M on xenograft biology and its interaction with dietary obesity were also evaluated in animal study. Cells overexpresssing PNPLA3I148M in low-dose FFA incubation showed more proliferation, migration, invasion, and less apoptosis (P<0.05). Low-dose FFA specifically activated JAK2/STAT3 phosphorylation of PNPLA3I148M cells via upregulation of interleukin-6. Animal study showed high-fat diet accelerated growth of xenografts derived from PNPLA3I148M cells incubated in low-dose FFA. In low oxidative stress, PNPLA3I148M initiated the hepatocyte malignant transformation through the activation of inflammation-mediated JAK/STAT pathway. Dietary obesity amplified the growth of tumor from PNPLA3I148M cells by interaction with local FFA incubation. Anti-inflammation and weight loss might be potential approaches for preventing HCC in high-risk population carrying PNPLA3 variant. PMID:27186262

  9. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator, wherein each thermographic layer comprises a plurality of respective thermographic sensors in a juxtaposed relationship with respect to each other. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  10. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator wherein each thermographic layer comprises a plurality of respective thermographic phosphors. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  11. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MaCarthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  12. Renoprotective effect of DPP-4 inhibitors against free fatty acid-bound albumin-induced renal proximal tubular cell injury.

    PubMed

    Tanaka, Yuki; Kume, Shinji; Chin-Kanasaki, Masami; Araki, Hisazumi; Araki, Shin-ichi; Ugi, Satoshi; Sugaya, Takeshi; Uzu, Takashi; Maegawa, Hiroshi

    2016-02-12

    Dipeptidyl peptidase (DPP)-4 inhibitors, a new class of antidiabetic agent, have recently been suggested to exert pleiotropic effects beyond glucose lowering. Renal prognosis in patients with diabetic nephropathy depends on the severity of tubulointerstitial injury induced by massive proteinuria. We thus examined the renoprotective effect of DPP-4 inhibitors on inflammation in cultured mouse proximal tubular cells stimulated with free fatty acid (FFA)-bound albumin. Linagliptin and higher concentrations of sitagliptin, vildagliptin, and alogliptin all inhibited FFA-bound albumin-induced increases in mRNA expression of MCP-1 in cultured mouse proximal tubular cells. Furthermore, linagliptin significantly inhibited tubulointerstitial injury induced by peritoneal injection of FFA-bound albumin, such as inflammation, fibrosis, and apoptosis, in mice without altering systemic characteristics including body weight, fasting blood glucose, and food intake. These results indicate that DPP-4 inhibitors pleiotropically exert a direct renoprotective effect, and may serve as an additional therapeutic strategy to protect proximal tubular cells against proteinuria in patients with diabetic nephropathy. PMID:26802469

  13. Muon and neutrino fluxes

    NASA Technical Reports Server (NTRS)

    Edwards, P. G.; Protheroe, R. J.

    1985-01-01

    The result of a new calculation of the atmospheric muon and neutrino fluxes and the energy spectrum of muon-neutrinos produced in individual extensive air showers (EAS) initiated by proton and gamma-ray primaries is reported. Also explained is the possibility of detecting atmospheric nu sub mu's due to gamma-rays from these sources.

  14. Electrostatic heat flux instabilities

    NASA Technical Reports Server (NTRS)

    Morrison, P. J.; Ionson, J. A.

    1980-01-01

    The electrostatic cyclotron and ion acoustic instabilities in a plasma driven by a combined heat flux and current were investigated. The minimum critical heat conduction speed (above which the plasma is unstable) is given as a function of the ratio of electron to ion temperatures.

  15. Radiative Flux Analysis

    DOE Data Explorer

    Long, Chuck [NOAA

    2008-05-14

    The Radiative Flux Analysis is a technique for using surface broadband radiation measurements for detecting periods of clear (i.e. cloudless) skies, and using the detected clear-sky data to fit functions which are then used to produce continuous clear-sky estimates. The clear-sky estimates and measurements are then used in various ways to infer cloud macrophysical properties.

  16. Enhanced free fatty acid production by codon-optimized Lactococcus lactis acyl-ACP thioesterase gene expression in Escherichia coli using crude glycerol.

    PubMed

    Lee, Sunhee; Park, Soohyun; Park, Chulhwan; Pack, Seung Pil; Lee, Jinwon

    2014-12-01

    Fatty acid production and composition are determined by the type of acyl-acyl carrier protein thioesterases (acyl-ACP TEs) expressed in Escherichia coli. Bacterial acyl-ACP TEs from Lactococcus lactis (SGJS47), Enterococcus faecalis (SGJS49), and Burkholderia cepacia (SGJS50) were codon-optimized and expressed in E. coli for enhanced fatty acid production. Samples were extracted at the lag, log, and stationary phases of cell growth, and gene expression levels of the codon optimized acy-ACP TEs as well as fatty acid production were monitored. At 24h after initiation of gene expression, the OPLlTE expression level and fatty acid production in SGJS47 increased up to 15.8-fold and 3.2-fold compared to the control and other recombinant strains, respectively. Additionally, in SGJS47, improvement in free fatty acid (FFA) composition, high-specificity production of short-chain fatty acids (C8, C10) and unsaturated fatty acids (C16:1) was achieved in crude glycerol medium condition. Compared with control strain, the percentage of FFAs (C8 and C10) was enhanced by approximately 16- to 21-fold, C16:1 FFA ratio increased approximately 18-fold. Observation of codon-optimized acyl-ACP TE genes expression level in E. coli may be useful for understanding mechanisms towards improving fatty acid production. Engineered strains have the potential to overproduce specific FFAs and thereby reduce the cost of fatty acid production by using industrially inexpensive carbon sources. PMID:25442943

  17. Exogenous Insulin Enhances Glucose-Stimulated Insulin Response in Healthy Humans Independent of Changes in Free Fatty Acids

    PubMed Central

    Lopez, Ximena; Cypess, Aaron; Manning, Raquel; O'Shea, Sheila; Kulkarni, Rohit N.

    2011-01-01

    Context: Islet β-cells express both insulin receptors and insulin signaling proteins. Recent studies suggest insulin signaling is physiologically important for glucose sensing. Objective: Preexposure to insulin enhances glucose-stimulated insulin secretion (GSIS) in healthy humans. We evaluated whether the effect of insulin to potentiate GSIS is modulated through regulation of free fatty acids (FFA). Design and Setting: Subjects were studied on three occasions in this single-site study at an academic institution clinical research center. Patients: Subjects included nine healthy volunteers. Interventions: Glucose-induced insulin response was assessed on three occasions after 4 h saline (low insulin/sham) or isoglycemic-hyperinsulinemic (high insulin) clamps with or without intralipid and heparin infusion, using B28 Asp-insulin that could be distinguished from endogenous insulin immunologically. During the last 80 min of all three clamps, additional glucose was administered to stimulate insulin secretion (GSIS) with glucose concentrations maintained at similar concentrations during all studies. Main Outcome Measure: β-Cell response to glucose stimulation was assessed. Results: Preexposure to exogenous insulin increased the endogenous insulin-secretory response to glucose by 32% compared with sham clamp (P = 0.001). This was accompanied by a drop in FFA during hyperinsulinemic clamp compared with the sham clamp (0.06 ± 0.02 vs. 0.60 ± 0.09 mEq/liter, respectively), which was prevented during the hyperinsulinemic clamp with intralipid/heparin infusion (1.27 ± 0.17 mEq/liter). After preexposure to insulin with intralipid/heparin infusion to maintain FFA concentration, GSIS was 21% higher compared with sham clamp (P < 0.04) and similar to preexposure to insulin without intralipid/heparin (P = 0.2). Conclusions: Insulin potentiates glucose-stimulated insulin response independent of FFA concentrations in healthy humans. PMID:21956413

  18. Free Fatty Acids Increase Intracellular Lipid Accumulation and Oxidative Stress by Modulating PPARα and SREBP-1c in L-02 Cells.

    PubMed

    Qin, Shumin; Yin, Jinjin; Huang, Keer

    2016-07-01

    Excessive fat accumulation and increased oxidative stress contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the mechanisms underlying the development of steatosis are not entirely understood. The present study was undertaken to establish an experimental model of hepatocellular steatosis with a fat overaccumulation profile in which the effects of oxidative stress could be studied in L-02 cells. We investigated the effects of free fatty acids (FFA) (palmitate:oleate, 1:2) on lipid accumulation and oxidative stress and their possible mechanisms in L-02 cells. High concentrations of fatty acids significantly induced excessive lipid accumulation and oxidative stress in L-02 cells, which could only be reversed with 50 μΜ WY14643 (the PPARα agonist). Immunoblotting and qPCR analyses revealed that FFA downregulated the expression of proliferator-activated receptor alpha (PPARα), which contributed to the increased activation of sterol regulatory element binding protein-1c (SREBP-1c). These results suggest that FFA induce lipid accumulation and oxidative stress in L-02 cells by upregulating SREBP-1c expression through the suppression of PPARα. PMID:27270405

  19. Granulocyte colony-stimulating factor (G-CSF): A saturated fatty acid-induced myokine with insulin-desensitizing properties in humans

    PubMed Central

    Ordelheide, Anna-Maria; Gommer, Nadja; Böhm, Anja; Hermann, Carina; Thielker, Inga; Machicao, Fausto; Fritsche, Andreas; Stefan, Norbert; Häring, Hans-Ulrich; Staiger, Harald

    2016-01-01

    Objective Circulating long-chain free fatty acids (FFAs) are important metabolic signals that acutely enhance fatty acid oxidation, thermogenesis, energy expenditure, and insulin secretion. However, if chronically elevated, they provoke inflammation, insulin resistance, and β-cell failure. Moreover, FFAs act via multiple signaling pathways as very potent regulators of gene expression. In human skeletal muscle cells differentiated in vitro (myotubes), we have shown in previous studies that the expression of CSF3, the gene encoding granulocyte colony-stimulating factor (G-CSF), is markedly induced upon FFA treatment and exercise. Methods and results We now report that CSF3 is induced in human myotubes by saturated, but not unsaturated, FFAs via Toll-like receptor 4-dependent and -independent pathways including activation of Rel-A, AP-1, C/EBPα, Src, and stress kinases. Furthermore, we show that human adipocytes and myotubes treated with G-CSF become insulin-resistant. In line with this, a functional polymorphism in the CSF3 gene affects adipose tissue- and whole-body insulin sensitivity and glucose tolerance in human subjects with elevated plasma FFA concentrations. Conclusion G-CSF emerges as a new player in FFA-induced insulin resistance and thus may be of interest as a target for prevention and treatment of type 2 diabetes. PMID:27069870

  20. Pretreatment by low-dose fibrates protects against acute free fatty acid-induced renal tubule toxicity by counteracting PPAR{alpha} deterioration

    SciTech Connect

    Takahashi, Kyoko; Kamijo, Yuji; Hora, Kazuhiko; Hashimoto, Koji; Higuchi, Makoto; Nakajima, Takero; Ehara, Takashi; Shigematsu, Hidekazu; Gonzalez, Frank J.; Aoyama, Toshifumi

    2011-05-01

    Development of a preventive strategy against tubular damage associated with proteinuria is of great importance. Recently, free fatty acid (FFA) toxicities accompanying proteinuria were found to be a main cause of tubular damage, which was aggravated by insufficiency of peroxisome proliferator-activated receptor alpha (PPAR{alpha}), suggesting the benefit of PPAR{alpha} activation. However, an earlier study using a murine acute tubular injury model, FFA-overload nephropathy, demonstrated that high-dose treatment of PPAR{alpha} agonist (0.5% clofibrate diet) aggravated the tubular damage as a consequence of excess serum accumulation of clofibrate metabolites due to decreased kidney elimination. To induce the renoprotective effects of PPAR{alpha} agonists without drug accumulation, we tried a pretreatment study using low-dose clofibrate (0.1% clofibrate diet) using the same murine model. Low-dose clofibrate pretreatment prevented acute tubular injuries without accumulation of its metabolites. The tubular protective effects appeared to be associated with the counteraction of PPAR{alpha} deterioration, resulting in the decrease of FFAs influx to the kidney, maintenance of fatty acid oxidation, diminution of intracellular accumulation of undigested FFAs, and attenuation of disease developmental factors including oxidative stress, apoptosis, and NF{kappa}B activation. These effects are common to other fibrates and dependent on PPAR{alpha} function. Interestingly, however, clofibrate pretreatment also exerted PPAR{alpha}-independent tubular toxicities in PPAR{alpha}-null mice with FFA-overload nephropathy. The favorable properties of fibrates are evident when PPAR{alpha}-dependent tubular protective effects outweigh their PPAR{alpha}-independent tubular toxicities. This delicate balance seems to be easily affected by the drug dose. It will be important to establish the appropriate dosage of fibrates for treatment against kidney disease and to develop a novel PPAR

  1. Comparative study on the in vivo and in vitro antilipolytic effects of etofibrate, nicotinic acid and clofibrate in the rat.

    PubMed

    Bocos, C; Herrera, E

    1996-12-20

    The release of both glycerol and free fatty acids (FFA) into a medium by epididymal fat pad pieces from fed rats incubated in Krebs Ringer bicarbonate-albumin buffer supplemented or not with epinephrine decreased more in the presence of etofibrate than in the presence of equimolecular doses of nicotinic acid or clofibrate. The first drug was the only one to stimulate the rate of fatty acid re-esterification when incubations were done under basal conditions. By 3 h after their acute oral administration all three drugs decreased plasma FFA levels, although the effect from etofibrate was largest, the drugs enhanced or decreased plasma glycerol levels depending on both the dose and the time after treatment. Plasma triglycerides also decreased at 3 h after oral drug administration, and this effect was similar with etofibrate and nicotinic acid but less with clofibrate. With the exception of a decrease at 7 h after the highest dose (1.2 mmol/kg) of either etofibrate or nicotinic acid (but not clofibrate), plasma cholesterol levels remained stable at 7 h after the respective treatments. Thus, the hypocholesterolemic effect of these drugs seems secondary to their hypotriglyceridemic effect, which would be a consequence of their respective antilipolytic actions, and follows an efficiency sequence of etofibrate, nicotinic acid and clofibrate. PMID:21781742

  2. Oil palm trunk and sugarcane bagasse derived solid acid catalysts for rapid esterification of fatty acids and moisture-assisted transesterification of oils under pseudo-infinite methanol.

    PubMed

    Ezebor, Francis; Khairuddean, Melati; Abdullah, Ahmad Zuhairi; Boey, Peng Lim

    2014-04-01

    The use of pseudo-infinite methanol in increasing the rate of esterification and transesterification reactions was studied using oil palm trunk (OPT) and sugarcane bagasse (SCB) derived solid acid catalysts. The catalysts were prepared by incomplete carbonisation at 400°C for 8h, followed by sulfonation at 150°C for 15h and characterised using TGA/DTA, XRD, FT-IR, SEM-EDS, EA and titrimetric determinations of acid sites. Under optimal reaction conditions, the process demonstrated rapid esterification of palmitic acid, with FAME yields of 93% and 94% in 45min for OPT and SCB catalysts, respectively. With the process, moisture levels up to 16.7% accelerated the conversion of low FFA oils by sulfonated carbon catalysts, through moisture-induced violent bumping. Moisture assisted transesterification of palm olein containing 1.78% FFA and 8.33% added water gave FAME yield of 90% in 10h, which was two folds over neat oil. PMID:24561631

  3. Optical heat flux gauge

    DOEpatents

    Noel, B.W.; Borella, H.M.; Cates, M.R.; Turley, W.D.; MacArthur, C.D.; Cala, G.C.

    1991-04-09

    A heat flux gauge is disclosed comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator, wherein each thermographic layer comprises a plurality of respective thermographic sensors in a juxtaposed relationship with respect to each other. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable. 9 figures.

  4. Atmospheric lepton fluxes

    NASA Astrophysics Data System (ADS)

    Gaisser, Thomas K.

    2015-08-01

    This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric νμ and νe are discussed, along with the implications of the muon charge ratio for the νµ / ν̅µ ratio. Methods to account for effects of the knee in the primary cosmic-ray spectrum and the energy-dependence of hadronic interactions on the neutrino fluxes are discussed and illustrated in the context of recent results from IceCube. A simple numerical/analytic method is proposed for systematic investigation of uncertainties in neutrino fluxes arising from uncertainties in the primary cosmic-ray spectrum/composition and hadronic interactions.

  5. Collapse of flux tubes

    NASA Astrophysics Data System (ADS)

    Wilets, L.; Puff, R. D.

    1995-01-01

    The dynamics of an idealized, infinite, MIT-type flux tube is followed in time as the interior evolves from a pure gluon field to a q¯q plasma. We work in color U(1). q¯q pair formation is evaluated according to the Schwinger mechanism using the results of Brink and Pavel. The motion of the quarks toward the tube end caps is calculated by a Boltzmann equation including collisions. The tube undergoes damped radial oscillations until the electric field settles down to zero. The electric field stabilizes the tube against pinch instabilities; when the field vanishes, the tube disintegrates into mesons. There is only one free parameter in the problem, namely the initial flux tube radius, to which the results are very sensitive. Among various quantities calculated is the mean energy of the emitted pions.

  6. Effect of unsaturated fatty acids and triglycerides from soybeans on milk fat synthesis and biohydrogenation intermediates in dairy cattle.

    PubMed

    Boerman, J P; Lock, A L

    2014-11-01

    Increased rumen unsaturated fatty acid (FA) load is a risk factor for milk fat depression. This study evaluated if increasing the amount of unsaturated FA in the diet as triglycerides or free FA affected feed intake, yield of milk and milk components, and feed efficiency. Eighteen Holstein cows (132 ± 75 d in milk) were used in a replicated 3 × 3 Latin square design. Treatments were a control (CON) diet, or 1 of 2 unsaturated FA (UFA) treatments supplemented with either soybean oil (FA present as triglycerides; TAG treatment) or soybean FA distillate (FA present as free FA; FFA treatment). The soybean oil contained a higher concentration of cis-9 C18:1 (26.0 vs. 11.8 g/100g of FA) and lower concentrations of C16:0 (9.6 vs. 15.0 g/100g of FA) and cis-9,cis-12 C18:2 (50.5 vs. 59.1g/100g of FA) than the soybean FA distillate. The soybean oil and soybean FA distillate were included in the diet at 2% dry matter (DM) to replace soyhulls in the CON diet. Treatment periods were 21 d, with the final 4 d used for sample and data collection. The corn silage- and alfalfa silage-based diets contained 23% forage neutral detergent fiber and 17% crude protein. Total dietary FA were 2.6, 4.2, and 4.3% of diet DM for CON, FFA, and TAG treatments, respectively. Total FA intake was increased 57% for UFA treatments and was similar between FFA and TAG. The intakes of individual FA were similar, with the exception of a 24 g/d lower intake of C16:0 and a 64 g/d greater intake of cis-9 C18:1 for the TAG compared with the FFA treatment. Compared with CON, the UFA treatments decreased DM intake (1.0 kg/d) but increased milk yield (2.2 kg/d) and milk lactose concentration and yield. The UFA treatments reduced milk fat concentration, averaging 3.30, 3.18, and 3.11% for CON, FFA, and TAG treatments, respectively. Yield of milk fat, milk protein, and 3.5% fat-corrected milk remained unchanged when comparing CON with the UFA treatments. No differences existed in the yield of milk or milk

  7. NEUTRON FLUX INTENSITY DETECTION

    DOEpatents

    Russell, J.T.

    1964-04-21

    A method of measuring the instantaneous intensity of neutron flux in the core of a nuclear reactor is described. A target gas capable of being transmuted by neutron bombardment to a product having a resonance absorption line nt a particular microwave frequency is passed through the core of the reactor. Frequency-modulated microwave energy is passed through the target gas and the attenuation of the energy due to the formation of the transmuted product is measured. (AEC)

  8. Reconnecting Flux Ropes

    NASA Astrophysics Data System (ADS)

    Gekelman, Walter; van Compernolle, Bart

    2012-10-01

    Magnetic flux ropes are due to helical currents and form a dense carpet of arches on the surface of the sun. Occasionally one tears loose as a coronal mass ejection and its rope structure is detected by satellites close to the earth. Current sheets can tear into filaments and these are nothing other than flux ropes. Ropes are not static, they exert mutual JxB forces causing them to twist about each other and merge. Kink instabilities cause them to violently smash into each other and reconnect at the point of contact. We report on experiments done in the large plasma device (LAPD) at UCLA (L=17m,dia=60cm,0.3<=B0z<=2.5kG,n˜2x10^12cm-3)on three dimensional flux ropes. Two, three or more magnetic flux ropes are generated from initially adjacent pulsed current channels in a background magnetized plasma. The currents and magnetic fields form exotic shapes with no ignorable direction and no magnetic nulls. Volumetric space-time data show multiple reconnection sites with time-dependent locations. The concept of a quasi-separatrix layer (QSL), a tool to understand 3D reconnection without null points. In our experiment the QSL is a narrow ribbon-like region(s) that twists between field lines. Within the QSL(s) field lines that start close to one another rapidly diverge as they pass through one or more reconnection regions. When the field lines are tracked they are observed to slip along the QSL when reconnection occurs. The Heating and other co-existing waves will be presented.

  9. Heat Flux Sensor Testing

    NASA Technical Reports Server (NTRS)

    Clark, D. W.

    2002-01-01

    This viewgraph presentation provides information on the following objectives: Developing secondary calibration capabilities for MSFC's (Marshall Space Flight Center) Hot Gas Facility (HGF), a Mach 4 Aerothermal Wind Tunnel; Evaluating ASTM (American Society for Testing and Materials) slug/ thinskin calorimeters against current HGF heat flux sensors; Providing verification of baselined AEDC (Arnold Engineering Development Center) / Medtherm gage calibrations; Addressing future calibration issues involving NIST (National Institute of Standards and Technology) certified radiant gages.

  10. Transmantle flux tectonics

    NASA Technical Reports Server (NTRS)

    Finn, V. J.; Dolginov, A. Z.; Baker, V. R.

    1993-01-01

    Venus, Earth, and Mars have surfaces that display topographic domes and depressions with quasi-circular planimetric shapes, relief of 0 to several km, and large spatial scales (10(exp 2) to 10(exp 4) km). Our morphostructural mapping reveals hierarchical arrangements of these features. They are explained by a model of long-acting mantle convection, as a particular case of convection in a stratified and random inhomogeneous medium, which develops the form of a hierarchy of different convective pattern scales, each arising from different levels in the mantle. The hypothesis of transmantle flux tectonics parsimoniously explains a diversity of seemingly unrelated terrestrial planetary phenomena, including Earth megaplumes, global resurfacing epochs on Venus, and cyclic ocean formation and global climate change for Mars. All these phenomenon are hypothesized to be parsimoniously explained by a process of transmantle flux tectonics in which long-acting mantle convection generates stresses in blocks of planetary lithosphere to produce distinctive quasi-circular global-hierarchical morphostructure (QGM) patterns. Transmantle flux tectonics differs from plume tectonics in that individual plumes are not considered in isolation. Rather, a wholly interactive process is envisioned in which various spatial and temporal scales of convection operate contemporaneously and hierarchically within other scales. This process of continual change by hierarchical convective cells affects the surface at varying temporal and spatial scales, and its effects are discernable through their relic geological manifestations, the QGM patterns.

  11. Stabilization of moduli by fluxes

    SciTech Connect

    Behrndt, Klaus

    2004-12-10

    In order to fix the moduli, non-trivial fluxes might the essential input. We summarize different aspects of compactifications in the presence of fluxes, as there is the relation to generalized Scherk-Schwarz reductions and gauged supergravity but also the description of flux-deformed geometries in terms of G-structures and intrinsic torsion.

  12. Pantethine stimulates lipolysis in adipose tissue and inhibits cholesterol and fatty acid synthesis in liver and intestinal mucosa in the normolipidemic rat.

    PubMed

    Bocos, C; Herrera, E

    1998-08-01

    In vitro effects of pantethine on adipose tissue lipolysis and on both hepatic and intestinal cholesterol and fatty acid synthesis in normolipidemic rats are determined and related to their respective in vivo hypolipidemic effects after acute oral administration. At 3, 5, 7 and 24 h after a single high dose of pantethine to rats, free fatty acids (FFA), cholesterol and triglycerides levels decreased whereas plasma glycerol increased, the effect becoming significant at 7 h. The release of glycerol and FFA by epididymal fat pad pieces from rats was measured in Krebs Ringer bicarbonate-albumin buffer supplemented or not with epinephrine and several concentrations of pantethine (0, 10(-5), 10(-4), or 10(-3) M), and it turned out to be enhanced as pantethine concentration increased. Besides, when glucose was present in the medium, this drug lowered fatty acid re-esterification in a dose-dependent manner, the effect being specially evident in the presence of epinephrine. In vitro synthesis of both cholesterol and fatty acids by slices of liver or intestinal epithelial cells was depressed as the concentration of pantethine increased in the medium. Thus, an inhibition of both cholesterolgenesis and lipogenesis seems to contribute to the hypocholesterolemic and hypotriglyceridemic effects of pantethine. On the other hand, the stimulation of lipolysis and the inhibition of fatty acid re-esterification on adipose tissue caused by pantethine must be counteracted by a high fatty acid oxidation in the liver which would explain the decrease in FFA and the increase in glycerol levels detected in the plasma of the pantethine-treated animals. PMID:21781882

  13. Thermal flux transfer system

    NASA Technical Reports Server (NTRS)

    Freggens, R. A. (Inventor)

    1973-01-01

    A thermal flux transfer system for use in maintaining the thrust chamber of an operative reaction motor at given temperatures is described. The system is characterized by an hermetically sealed chamber surrounding a thrust chamber to be cooled, with a plurality of parallel, longitudinally spaced, disk-shaped wick members formed of a metallic mesh and employed in delivering a working fluid, in its liquid state, radially toward the thrust chamber and delivering the working fluid, in its vapor state, away from the nozzle for effecting a cooling of the nozzle, in accordance with known principles of an operating heat pipe.

  14. High flux reactor

    DOEpatents

    Lake, James A.; Heath, Russell L.; Liebenthal, John L.; DeBoisblanc, Deslonde R.; Leyse, Carl F.; Parsons, Kent; Ryskamp, John M.; Wadkins, Robert P.; Harker, Yale D.; Fillmore, Gary N.; Oh, Chang H.

    1988-01-01

    A high flux reactor is comprised of a core which is divided into two symetric segments housed in a pressure vessel. The core segments include at least one radial fuel plate. The spacing between the plates functions as a coolant flow channel. The core segments are spaced axially apart such that a coolant mixing plenum is formed between them. A channel is provided such that a portion of the coolant bypasses the first core section and goes directly into the mixing plenum. The outlet coolant from the first core segment is mixed with the bypass coolant resulting in a lower inlet temperature to the lower core segment.

  15. The metabolic profile of growing lambs fed diets rich in unsaturated fatty acids.

    PubMed

    Steppa, R; Szkudelska, K; Wójtowski, J; Stanisz, M; Szumacher-Strabel, M; Czyżak-Runowska, G; Cieślak, A; Markiewicz-Kęszycka, M; Pietrzak, M

    2014-10-01

    The effect of two diets enriched with unsaturated fatty acids--one containing the addition of dried distillers grains with solubles (DGS) and the other the addition of false flax--Camelina sativa cake (CS)--on some metabolic parameters and hormone concentration in growing lambs was determined in this experiment. A total of 21 ram lambs of the Polish Whiteheaded mutton sheep were divided into three groups (the control, receiving DGS and CS). The diets were administered to animals for 6 weeks. During the experiment, peripheral blood was collected. Glucose (GL), total cholesterol (CH), triglycerides (TG), free fatty acids (FFA), insulin (IN), leptin (LE), triiodothyronine (T3) and thyroxine (T4) were assayed in serum. The age-dependent reduction in CH and TG limited by both experimental diets were observed. A significant increase in FFA concentration was observed in samples collected in the last, that is, third, time period. This was most probably caused by a 12-h pre-slaughter fasting period. A significantly lower dynamic of FFA increase in that experimental period was found in animals receiving the experimental feed. Insulin concentration in DGS-receiving lambs was increased, in contrast to the CS-receiving lambs, in which it was lower when compared to the control. LE concentration was decreased by both experimental diets, more markedly in the DGS-receiving animals. No differences between the experimental groups and the control were observed in T3 and T4 concentrations. The effect of 12-h pre-slaughter fasting was statistically highly significant for the levels of examined blood markers and hormones, except for TG and IN in the group of lambs receiving the experimental diet with CS. PMID:24387699

  16. Two-step in situ biodiesel production from microalgae with high free fatty acid content.

    PubMed

    Dong, Tao; Wang, Jun; Miao, Chao; Zheng, Yubin; Chen, Shulin

    2013-05-01

    The yield of fatty acid methyl ester (FAME) from microalgae biomass is generally low via traditional extraction-conversion route due to the deficient solvent extraction. In this study a two-step in situ process was investigated to obtain a high FAME yield from microalgae biomass that had high free fatty acids (FFA) content. This was accomplished with a pre-esterification process using heterogeneous catalyst to reduce FFA content prior to the base-catalyzed transesterification. The two-step in situ process resulted in a total FAME recovery up to 94.87±0.86%, which was much higher than that obtained by a one-step acid or base catalytic in situ process. The heterogeneous catalyst, Amberlyst-15, could be used for 8 cycles without significant loss in activity. This process have the potential to reduce the production cost of microalgae-derived FAME and be more environmental compatible due to the higher FAME yield with reduced catalyst consumption. PMID:23548399

  17. Free fatty acids sensitize dendritic cells to amplify TH1/TH17-immune responses.

    PubMed

    Stelzner, Kristin; Herbert, Diana; Popkova, Yulia; Lorz, Axel; Schiller, Jürgen; Gericke, Martin; Klöting, Nora; Blüher, Matthias; Franz, Sandra; Simon, Jan C; Saalbach, Anja

    2016-08-01

    Obesity is associated with body fat gain and impaired glucose metabolism. Here, we identified both body fat gain in obesity and impaired glucose metabolism as two independent risk factors for increased serum levels of free fatty acids (FFAs). Since obesity is associated with increased and/or delayed resolution of inflammation observed in various chronic inflammatory diseases such as psoriasis, we investigated the impact of FFAs on human monocyte-derived and mouse bone marrow-derived dendritic cell (DCs) functions relevant for the pathogenesis of chronic inflammation. FFAs such as palmitic acid (PA) and oleic acid (OA) did not affect the pro-inflammatory immune response of DCs. In contrast, PA and OA sensitize DCs resulting in augmented secretion of TH1/TH17-instructive cytokines upon pro-inflammatory stimulation. Interestingly, obesity in mice worsened a TH1/TH17-driven psoriasis-like skin inflammation. Strong correlation of the amount of total FFA, PA, and OA in serum with the severity of skin inflammation points to a critical role of FFA in obesity-mediated exacerbation of skin inflammation. Our data suggest that increased levels of FFAs might be a predisposing factor promoting a TH1/TH17-mediated inflammation such as psoriasis in response to an inflammatory danger signal. PMID:27214608

  18. Electroslag remelting with used fluxes

    SciTech Connect

    Yakovlev, N.F.; Sokha, Yu.S.; Oleinik, Yu.S.; Prokhorov, A.N.; Ol'shanskaya, T.V.

    1988-05-01

    The Ukranian Scientific-Research Institute of Specialty Steel collaborated with plants engaged in the production of quality metals to introduce a low-waste electroslag remelting (ESR) technology employing used fluxes. It was established that the fluoride (type ANF-1) and fluoride-oxide (type ANF-6) fluxes which are widely used in ESR still have a high content of calcium fluoride and alumina and a low impurity content after 8-10 h of ESR. In the ESR of steels with used fluxes, the content of monitored components in the final slags changes negligibly, while the content of most impurities decreases. The used flux is also characterized by a low concentration of phosphorus and sulfur. It was found that flux can be used 3-5 times when it makes up 50% of the flux mixture in the charge. The savings realized from the use of spent flux in ESR amounts to 4-9 rubles/ton steel.

  19. Computing the Flux Footprint

    NASA Astrophysics Data System (ADS)

    Wilson, J. D.

    2015-07-01

    We address the flux footprint for measurement heights in the atmospheric surface layer, comparing eddy diffusion solutions with those furnished by the first-order Lagrangian stochastic (or "generalized Langevin") paradigm. The footprint given by Langevin models differs distinctly from that given by the random displacement model (i.e. zeroth-order Lagrangian stochastic model) corresponding to its "diffusion limit," which implies that a well-founded theory of the flux footprint must incorporate the turbulent velocity autocovariance. But irrespective of the choice of the eddy diffusion or Langevin class of model as basis for the footprint, tuning relative to observations is ultimately necessary. Some earlier treatments assume Monin-Obukhov profiles for the mean wind and eddy diffusivity and that the effective Schmidt number (ratio of eddy viscosity to the tracer eddy diffusivity) in the neutral limit , while others calibrate the model to the Project Prairie Grass dispersion trials. Because there remains uncertainty as to the optimal specification of (or a related parameter in alternative theories, e.g. the Kolmogorov coefficient in Langevin models) it is recommended that footprint models should be explicit in this regard.

  20. Increasing serum Pre-adipocyte factor-1 (Pref-1) correlates with decreased body fat, increased free fatty acids, and level of recent alcohol consumption in excessive alcohol drinkers

    PubMed Central

    Liangpunsakul, Suthat; Bennett, Rachel; Westerhold, Chi; Ross, Ruth A.; Crabb, David W.; Lai, Xianyin; Witzmann, Frank A.

    2014-01-01

    Background Patients with alcoholic liver disease have been reported to have a significantly lower percentage of body fat (%BF) than controls. The mechanism for the reduction in %BF in heavy alcohol users has not been elucidated. In adipose tissue, Pref-1 is specifically expressed in pre-adipocytes but not in adipocytes. Pref-1 inhibits adipogenesis and elevated levels are associated with reduced adipose tissue mass. We investigated the association between serum Pref-1 and %BF, alcohol consumption, and serum free fatty acids (FFA) in a well-characterized cohort of heavy alcohol users compared to controls. Methods One hundred forty-eight subjects were prospectively recruited. The Time Line Follow-Back (TLFB) questionnaire was used to quantify the amount of alcohol consumed over the 30-day period before their enrollment. Anthropometric measurements were performed to calculate %BF. Serum Pref-1 and FFA were measured. Results Fifty-one subjects (mean age 32 ± 9 years, 88% men) were non-excessive drinkers whereas 97 were excessive drinkers (mean age 41 ± 18 years, 69% men). Compared to non-excessive drinkers, individuals with excessive drinking had significantly higher levels of Pref-1 (p < 0.01), FFA (p < 0.001), and lower %BF (p = 0.03). Serum levels of Pref-1 were associated with the amount of alcohol consumed during the previous 30 days. Serum Pref-1 was negatively correlated with %BF, but positively associated with serum FFA. Conclusions Our data suggest that elevated Pref-1 levels in excessive drinkers might inhibit the expansion of adipose tissue, decreasing %BF in alcoholics. Further work is needed to validate these findings and to better understand the role of Pref-1 and its clinical significance in subjects with heavy alcohol use. PMID:25449367

  1. Increasing serum pre-adipocyte factor-1 (Pref-1) correlates with decreased body fat, increased free fatty acids, and level of recent alcohol consumption in excessive alcohol drinkers.

    PubMed

    Liangpunsakul, Suthat; Bennett, Rachel; Westerhold, Chi; Ross, Ruth A; Crabb, David W; Lai, Xianyin; Witzmann, Frank A

    2014-12-01

    Patients with alcoholic liver disease have been reported to have a significantly lower percentage of body fat (%BF) than controls. The mechanism for the reduction in %BF in heavy alcohol users has not been elucidated. In adipose tissue, Pref-1 is specifically expressed in pre-adipocytes but not in adipocytes. Pref-1 inhibits adipogenesis and elevated levels are associated with reduced adipose tissue mass. We investigated the association between serum Pref-1 and %BF, alcohol consumption, and serum free fatty acids (FFA) in a well-characterized cohort of heavy alcohol users compared to controls. One hundred forty-eight subjects were prospectively recruited. The Time Line Follow-Back (TLFB) questionnaire was used to quantify the amount of alcohol consumed over the 30-day period before their enrollment. Anthropometric measurements were performed to calculate %BF. Serum Pref-1 and FFA were measured. Fifty-one subjects (mean age 32 ± 9 years, 88% men) were non-excessive drinkers whereas 97 were excessive drinkers (mean age 41 ± 18 years, 69% men). Compared to non-excessive drinkers, individuals with excessive drinking had significantly higher levels of Pref-1 (p<0.01), FFA (p < 0.001), and lower %BF (p = 0.03). Serum levels of Pref-1 were associated with the amount of alcohol consumed during the previous 30 days. Serum Pref-1 was negatively correlated with %BF, but positively associated with serum FFA. Our data suggest that elevated Pref-1 levels in excessive drinkers might inhibit the expansion of adipose tissue, decreasing %BF in alcoholics. Further work is needed to validate these findings and to better understand the role of Pref-1 and its clinical significance in subjects with heavy alcohol use. PMID:25449367

  2. Two-Stage Conversion of High Free Fatty Acid Jatropha curcas Oil to Biodiesel Using Brønsted Acidic Ionic Liquid and KOH as Catalysts

    PubMed Central

    Das, Subrata; Thakur, Ashim Jyoti; Deka, Dhanapati

    2014-01-01

    Biodiesel was produced from high free fatty acid (FFA) Jatropha curcas oil (JCO) by two-stage process in which esterification was performed by Brønsted acidic ionic liquid 1-(1-butylsulfonic)-3-methylimidazolium chloride ([BSMIM]Cl) followed by KOH catalyzed transesterification. Maximum FFA conversion of 93.9% was achieved and it reduced from 8.15 wt% to 0.49 wt% under the optimum reaction conditions of methanol oil molar ratio 12 : 1 and 10 wt% of ionic liquid catalyst at 70°C in 6 h. The ionic liquid catalyst was reusable up to four times of consecutive runs under the optimum reaction conditions. At the second stage, the esterified JCO was transesterified by using 1.3 wt% KOH and methanol oil molar ratio of 6 : 1 in 20 min at 64°C. The yield of the final biodiesel was found to be 98.6% as analyzed by NMR spectroscopy. Chemical composition of the final biodiesel was also determined by GC-MS analysis. PMID:24987726

  3. HONO fluxes from soil surfaces: an overview

    NASA Astrophysics Data System (ADS)

    Wu, Dianming; Sörgel, Matthias; Tamm, Alexandra; Ruckteschler, Nina; Rodriguez-Caballero, Emilio; Cheng, Yafang; Pöschl, Ulrich; Weber, Bettina

    2016-04-01

    Gaseous nitrous acid (HONO) contributes up to 80% of atmospheric hydroxyl (OH) radicals and is also linked to health risks through reactions with tobacco smoke forming carcinogens. Field and modeling results suggested a large unknown HONO source in the troposphere during daytime. By measuring near ground HONO mixing ratio, up to 30% of HONO can be released from forest, rural and urban ground as well as snow surfaces. This source has been proposed to heterogeneous reactions of nitrogen dioxide (NO2) on humic acid surfaces or nitric acid photolysis. Laboratory studies showed that HONO emissions from bulk soil samples can reach 258 ng m‑2 s‑1 (in term of nitrogen), which corresponding to 1.1 × 1012 molecules cm‑2 s‑1and ˜ 100 times higher than most of the field studies, as measured by a dynamic chamber system. The potential mechanisms for soil HONO emissions include chemical equilibrium of acid-base reaction and gas-liquid partitioning between soil nitrite and HONO, but the positive correlation of HONO fluxes with pH (largest at neutral and slightly alkaline) points to the dominance of the formation process by ammonia-oxidizing bacteria (AOB). In general soil surface acidity, nitrite concentration and abundance of ammonia-oxidizing bacteria mainly regulate the HONO release from soil. A recent study showed that biological soil crusts in drylands can also emit large quantities of HONO and NO, corresponding to ˜20% of global nitrogen oxide emissions from soils under natural vegetation. Due to large concentrations of microorganisms in biological soil crusts, particularly high HONO and NO emissions were measured after wetting events. Considering large areas of arid and arable lands as well as peatlands, up to 70% of global soils are able to emitting HONO. However, the discrepancy between large soil HONO emissions measured in lab and low contributions of HONO flux from ground surfaces in field as well as the role of microorganisms should be further investigated.

  4. PromptNuFlux: Prompt atmospheric neutrino flux calculator

    NASA Astrophysics Data System (ADS)

    Rottoli, Luca

    2015-11-01

    PromptNuFlux computes the prompt atmospheric neutrino flux E3Φ(GeV2/(cm2ssr)), including the total associated theory uncertainty, for a range of energies between E=103 GeV and E=107.5 GeV. Results are available for five different parametrizations of the input cosmic ray flux: BPL, H3P, H3A, H14a, H14b.

  5. Homogeneous, heterogeneous and enzymatic catalysis for transesterification of high free fatty acid oil (waste cooking oil) to biodiesel: a review.

    PubMed

    Lam, Man Kee; Lee, Keat Teong; Mohamed, Abdul Rahman

    2010-01-01

    In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel. PMID:20362044

  6. California's Future Carbon Flux

    NASA Astrophysics Data System (ADS)

    Xu, L.; Pyles, R. D.; Paw U, K.; Gertz, M.

    2008-12-01

    The diversity of the climate and vegetation systems in the state of California provides a unique opportunity to study carton dioxide exchange between the terrestrial biosphere and the atmosphere. In order to accurately calculate the carbon flux, this study couples the sophisticated analytical surface layer model ACASA (Advance Canopy-Atmosphere-Soil Algorithm, developed in the University of California, Davis) with the newest version of mesoscale model WRF (the Weather Research & Forecasting Model, developed by NCAR and several other agencies). As a multilayer, steady state model, ACASA incorporates higher-order representations of vertical temperature variations, CO2 concentration, radiation, wind speed, turbulent statistics, and plant physiology. The WRF-ACASA coupling is designed to identify how multiple environmental factors, in particularly climate variability, population density, and vegetation distribution, impact on future carbon cycle prediction across a wide geographical range such as in California.

  7. Quantitative Flux Ecoregions for AmeriFlux Using MODIS

    NASA Astrophysics Data System (ADS)

    Hoffman, F. M.; Hargrove, W. W.

    2004-12-01

    Multivariate Geographic Clustering was used with maps of climate, soils, and physiography and MODIS remotely sensed data products to statistically produce a series of the 90 most-different homogeneous flux-relevant ecoregions in the conterminous United States using a parallel supercomputer. Nine separate sets of flux ecoregions were produced; only two will be discussed here. Both the IB and IIIB maps were quantitatively constructed from subsets of the input data integrated during the local growing season (frost-free period) in every 1 km cell. Each map is shown two ways --- once with the 90 flux ecoregions colored randomly, and once using color combinations derived statistically from the first three Principal Component Axes. Although the underlying flux ecoregion polygons are the same in both cases, the statistically derived colors show the similarity of conditions within each flux ecoregion. Coloring the same map in this way shows the continuous gradient of changing flux environments across the US. The IB map, since it considers only abiotic environmental factors, represents flux-ecoregions based on potential vegetation. The IIIB map, since it contains remotely sensed MODIS information about existing vegetation, includes the effects of natural and anthropogenic disturbance, and represents actual or realized flux ecoregions. Thus, differences between the maps are attributable to human activity and natural disturbances. The addition of information on existing vegetation exerts a unifying effect on abiotic-only flux ecoregions. The Mississippi Valley and Corn Belt areas show large differences between the two maps. Map IIIB shows a mosaic of ``speckles'' in areas of intense human land use, ostensibly from disturbances like agriculture, irrigation, fertilization, and clearing. Such ``speckles'' are absent from areas devoid of intense human land use. Major cities are also evident in the IIIB map. We will use the quantitative similarity of the suite of flux

  8. Lithium metaborate flux in silicate analysis

    USGS Publications Warehouse

    Ingamells, C.O.

    1970-01-01

    Lithium metaborate is an effective flux for silicates and other rock-forming minerals. The glass resulting from fusion is mechanically strong, reasonably nonhygroscopic, and is readily soluble in dilute acids. These characteristics lead to its use in X-ray spectrography and in methods which require whole-rock solutions, such as atomic absorption and emission spectrometry. Difficulties have been encountered in the use of such techniques : a high-quality reagent has been difficult to obtain ; fusion conditions must be rather closely controlled; graphite crucibles used in the fusions need special treatment. Methods for overcoming these difficulties are outlined. Selected procedures for various instrumental methods of analysis are described. ?? 1970.

  9. Effect of oil extraction assisted by ultrasound on the physicochemical properties and fatty acid profile of pumpkin seed oil (Cucurbita pepo).

    PubMed

    Hernández-Santos, Betsabé; Rodríguez-Miranda, Jesús; Herman-Lara, Erasmo; Torruco-Uco, Juan G; Carmona-García, Roselis; Juárez-Barrientos, José M; Chávez-Zamudio, Rubí; Martínez-Sánchez, Cecilia E

    2016-07-01

    The effects of amplitude and time of ultrasound-assisted extraction on the physicochemical properties and the fatty acid profile of pumpkin seed oil (Cucurbita pepo) were evaluated. Ultrasound time (5-30 min) and the response variables amplitude (25-100%), extraction yield, efficiency, oxidative stability in terms of the free fatty acids (FFA) of the plant design comprising two independent experiments variables, peroxide (PV), p-anisidine (AV), totox value (TV) and the fatty acid profile were evaluated. The results were analyzed by multiple linear regression. The time and amplitude showed significant differences (P<0.05) for all variables. The highest yield of extraction was achieved at 5 min and amplitude of 62.5% (62%). However, the optimal ultrasound-assisted extraction conditions were as follows: ultrasound time of 26.34 min and amplitude of 89.02%. All extracts showed low FFA (2.75-4.93% oleic acid), PV (1.67-4.68 meq/kg), AV (1.94-3.69) and TV (6.25-12.55) values. The main fatty acids in all the extracts were oleic and linoleic acid. Therefore, ultrasound-assisted oil extraction had increased performance and reduced extraction time without affecting the oil quality. PMID:26964969

  10. Vorticity flux from active dimples

    NASA Astrophysics Data System (ADS)

    McKeon, Beverley; Sherwin, Spencer; Morrison, Jonathan

    2004-11-01

    The effect of surface depressions, or dimples, in reducing drag on golf balls is well-known. Here this concept is extended to using ``active" dimples to manipulate vorticity flux at the wall. Surface vorticity flux is governed by surface accelerations, pressure and shear stress gradients, and surface curvature. ``Active" (or vibrating) dimples may generate vorticity flux by each of these terms, making them an excellent candidate for a basic study of flux manipulation, by which flow control may be achieved. Flow over an active dimple in fully-developed laminar channel flow is simulated with velocity boundary conditions developed from a linearized perturbation method imposed at the wall. This simple model cannot capture flow separation, but gives insight into the most straightforward means of flux generation from the concave surface. Vorticity flux due to dimple geometry and motion is quantified, and enhancements of two to three orders of magnitude in peak vorticity over the static dimple case are observed.

  11. Heat-Flux-Measuring Facility

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1990-01-01

    Apparatus simulates conditions in turbine engines. Automated facility generates and measures transient and steady-state heat fluxes at flux densities from 0.3 to 6 MW/m(Sup2) and temperatures from 100 to 1,200 K. Positioning arm holds heat-flux gauge at focal point of arc lamp. Arm previously chilled gauge in liquid nitrogen in Dewar flask. Cooling water flows through lamp to heat exchanger. Used to develop heat-flux gauges for turbine blades and to test materials for durability under rapidly changing temperatures.

  12. Measuring surface fluxes in CAPE

    NASA Technical Reports Server (NTRS)

    Kanemasu, E. T.; D-Shah, T.; Nie, Dalin

    1992-01-01

    Two stations (site 1612 and site 2008) were operated by the University of Georgia group from 6 July 1991 to 18 August 1991. The following data were collected continuously: surface energy fluxes (i.e., net radiation, soil heat fluxes, sensible heat flux and latent heat flux), air temperature, vapor pressure, soil temperature (at 1 cm depth), and precipitation. Canopy reflectance and light interception data were taken three times at each site between 6 July and 18 August. Soil moisture content was measured twice at each site.

  13. Characterization of stearidonic acid soybean oil enriched with palmitic acid produced by solvent-free enzymatic interesterification.

    PubMed

    Teichert, Sarah A; Akoh, Casimir C

    2011-09-14

    Stearidonic acid soybean oil (SDASO) is a plant source of n-3 polyunsaturated fatty acids (n-3 PUFAs). Solvent-free enzymatic interesterification was used to produce structured lipids (SLs) in a 1 L stir-batch reactor with a 1:2 substrate mole ratio of SDASO to tripalmitin, at 65 °C for 18 h. Two SLs were synthesized using immobilized lipases, Novozym 435 and Lipozyme TL IM. Free fatty acids (FFAs) were removed by short-path distillation. SLs were characterized by analyzing FFA and FA (total and positional) contents, iodine and saponification values, melting and crystallization profiles, tocopherols, and oxidative stability. The SLs contained 8.15 and 8.38% total stearidonic acid and 60.84 and 60.63% palmitic acid at the sn-2 position for Novozym 435 SL and Lipozyme TL IM SL, respectively. The SLs were less oxidatively stable than SDASO due to a decrease in tocopherol content after purification of the SLs. The saponification values of the SLs were slightly higher than that of the SDASO. The melting profiles of the SLs were similar, but crystallization profiles differed. The triacylglycerol (TAG) molecular species of the SLs were similar to each other, with tripalmitin being the major TAG. SDASO's major TAG species comprised stearidonic and oleic acids or stearidonic, α-linolenic, and γ-linolenic acids. PMID:21830790

  14. South Atlantic meridional fluxes

    NASA Astrophysics Data System (ADS)

    Garzoli, Silvia L.; Baringer, Molly O.; Dong, Shenfu; Perez, Renellys C.; Yao, Qi

    2013-01-01

    The properties of the meridional overturning circulation (MOC) and associated meridional heat transport (MHT) and salt fluxes are analyzed in the South Atlantic. The oceanographic data used for the study consist of Expendable bathythermograph (XBT) data collected along 27 sections at nominally 35°S for the period of time 2002-2011, and Argo profile data collected in the region. Previous estimates obtained with a shorter record are improved and extended, using new oceanographic sections and wind fields. Different wind products are analyzed to determine the uncertainty in the Ekman component of the MHT derived from their use. Results of the analysis provide a 9-year time series of MHT, and volume transport in the upper layer of the MOC. Salt fluxes at 35°S are estimated using a parameter introduced by numerical studies, the Mov that represents the salt flux and helps determine the basin scale salt feedback associated with the MOC. Volume and heat transport by the western and eastern boundary currents are estimated, and their covariablity is examined. Analysis of the data shows that the South Atlantic is responsible for a northward MHT with a mean value of 0.54±0.14 PW. The MHT exhibits no significant trend from 2002 to 2011. The MOC varies from 14.4 to 22.7 Sv with a mean value of 18.1±2.3 Sv and the maximum overturning transport is found at a mean depth of 1250 m. Statistical analysis suggests that an increase of 1 Sv in the MOC leads to an increase of the MHT of 0.04±0.02 PW. Estimates of the Mov from data collected from three different kinds of observations, contrary to those obtained from models, feature a positive salt advection feedback (Mov<0) suggesting that freshwater perturbations will be amplified and that the MOC is bistable. In other words, the MOC might collapse with a large enough freshwater perturbation. Observations indicate that the mean value of the Brazil Current is -8.6±4.1 Sv at 24°S and -19.4±4.3 Sv at 35°S, increasing towards the

  15. Flood Frequency Analysis (FFA) in Spanish catchments

    NASA Astrophysics Data System (ADS)

    Mateo Lázaro, Jesús; Sánchez Navarro, José Ángel; García Gil, Alejandro; Edo Romero, Vanesa

    2016-07-01

    A frequency analysis of rainfall and flow from the available data and applications in Spain takes place. In the case of streamflow, various methods that can be grouped into two categories are used, (1) the gauged method which consist in the analysis of maximum flow rate annual series, and (2) the hydro-meteorological method which take into account processes with rainfall-runoff transformation models. The results are compared with observed data in historical series. Finally, six episodes with actual rainfall and flow record are analyzed. These episodes are also classified according to their frequency domain and results obtained from models are contrasted. To make this work we have used two applications launched in the University of Zaragoza: the SHEE program, which provides a simple and flexible working environment which allows the simultaneous management of the most actual and important databases from a hydrological point of view, highlighting the digital terrain models, the rainfall coverage and the curve number coverage, and that is suitable for the application of hydro-meteorological models; and the EHVE software, which is a hydrological statistical program for analysis of time series of extreme values, suitable for application in models of gauged data.

  16. KoFlux: Korean Regional Flux Network in AsiaFlux

    NASA Astrophysics Data System (ADS)

    Kim, J.

    2002-12-01

    AsiaFlux, the Asian arm of FLUXNET, held the Second International Workshop on Advanced Flux Network and Flux Evaluation in Jeju Island, Korea on 9-11 January 2002. In order to facilitate comprehensive Asia-wide studies of ecosystem fluxes, the meeting launched KoFlux, a new Korean regional network of long-term micrometeorological flux sites. For a successful assessment of carbon exchange between terrestrial ecosystems and the atmosphere, an accurate measurement of surface fluxes of energy and water is one of the prerequisites. During the 7th Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) held in Nagoya, Japan on 1-2 October 2001, the Implementation Committee of the Coordinated Enhanced Observing Period (CEOP) was established. One of the immediate tasks of CEOP was and is to identify the reference sites to monitor energy and water fluxes over the Asian continent. Subsequently, to advance the regional and global network of these reference sites in the context of both FLUXNET and CEOP, the Korean flux community has re-organized the available resources to establish a new regional network, KoFlux. We have built up domestic network sites (equipped with wind profiler and radiosonde measurements) over deciduous and coniferous forests, urban and rural rice paddies and coastal farmland. As an outreach through collaborations with research groups in Japan, China and Thailand, we also proposed international flux sites at ecologically and climatologically important locations such as a prairie on the Tibetan plateau, tropical forest with mixed and rapid land use change in northern Thailand. Several sites in KoFlux already begun to accumulate interesting data and some highlights are presented at the meeting. The sciences generated by flux networks in other continents have proven the worthiness of a global array of micrometeorological flux towers. It is our intent that the launch of KoFlux would encourage other scientists to initiate and

  17. Carbon Dioxide Flux Measurement Systems (CO2Flux) Handbook

    SciTech Connect

    Fischer, M

    2005-01-01

    The Southern Great Plains (SGP) carbon dioxide flux (CO2 flux) measurement systems provide half-hour average fluxes of CO2, H2O (latent heat), and sensible heat. The fluxes are obtained by the eddy covariance technique, which computes the flux as the mean product of the vertical wind component with CO2 and H2O densities, or estimated virtual temperature. A three-dimensional sonic anemometer is used to obtain the orthogonal wind components and the virtual (sonic) temperature. An infrared gas analyzer is used to obtain the CO2 and H2O densities. A separate sub-system also collects half-hour average measures of meteorological and soil variables from separate 4-m towers.

  18. Flux Compression Magnetic Nozzle

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

    2001-01-01

    In pulsed fusion propulsion schemes in which the fusion energy creates a radially expanding plasma, a magnetic nozzle is required to redirect the radially diverging flow of the expanding fusion plasma into a rearward axial flow, thereby producing a forward axial impulse to the vehicle. In a highly electrically conducting plasma, the presence of a magnetic field B in the plasma creates a pressure B(exp 2)/2(mu) in the plasma, the magnetic pressure. A gradient in the magnetic pressure can be used to decelerate the plasma traveling in the direction of increasing magnetic field, or to accelerate a plasma from rest in the direction of decreasing magnetic pressure. In principle, ignoring dissipative processes, it is possible to design magnetic configurations to produce an 'elastic' deflection of a plasma beam. In particular, it is conceivable that, by an appropriate arrangement of a set of coils, a good approximation to a parabolic 'magnetic mirror' may be formed, such that a beam of charged particles emanating from the focal point of the parabolic mirror would be reflected by the mirror to travel axially away from the mirror. The degree to which this may be accomplished depends on the degree of control one has over the flux surface of the magnetic field, which changes as a result of its interaction with a moving plasma.

  19. Regulation of flux through metabolic cycles

    SciTech Connect

    Walsh, K.

    1984-01-01

    The branchpoint of the tricarboxylic acid and glyoxylate shunt was characterized in the intact organism by a multidimensional approach. Theory and methodology were developed to determine velocities for the net flow of carbon through the major steps of acetate metabolism in E. coli. Rates were assigned based on the /sup 13/C-NMR spectrum of intracellular glutamate, measured rates of substrate incorporation into end products, the constituent composition of E. coli and a series of conservation equations which described the system at steady state. The in vivo fluxes through the branchpoint of the tricarboxylic acid and glyoxylate cycles were compared to rates calculated from the kinetic constants of the branchpoint enzymes and the intracellular concentrations of their substrates. These studies elucidated the role of isocitrate dehydrogenase phosphorylation in the Krebs cycle and led to the development of a generalized mathematical description of the sensitivity of branchpoints to regulatory control. This theoretical analysis was termed the branchpoint effect and it describes conditions which result in large changes in the flux through an enzyme even though that enzyme is not subject to direct regulatory control. The theoretical and experimental characterization of this system provided a framework to study the effects of enzyme overproduction and underproduction on metabolic processes in the cell. An in vivo method was developed to determine the extent to which an enzyme catalyzes a rate-controlling reaction. The enzyme chosen for this study was citrate synthase.

  20. A rheostat mechanism governs the bifurcation of carbon flux in mycobacteria.

    PubMed

    Murima, Paul; Zimmermann, Michael; Chopra, Tarun; Pojer, Florence; Fonti, Giulia; Dal Peraro, Matteo; Alonso, Sylvie; Sauer, Uwe; Pethe, Kevin; McKinney, John D

    2016-01-01

    Fatty acid metabolism is an important feature of the pathogenicity of Mycobacterium tuberculosis during infection. Consumption of fatty acids requires regulation of carbon flux bifurcation between the oxidative TCA cycle and the glyoxylate shunt. In Escherichia coli, flux bifurcation is regulated by phosphorylation-mediated inhibition of isocitrate dehydrogenase (ICD), a paradigmatic example of post-translational mechanisms governing metabolic fluxes. Here, we demonstrate that, in contrast to E. coli, carbon flux bifurcation in mycobacteria is regulated not by phosphorylation but through metabolic cross-activation of ICD by glyoxylate, which is produced by the glyoxylate shunt enzyme isocitrate lyase (ICL). This regulatory circuit maintains stable partitioning of fluxes, thus ensuring a balance between anaplerosis, energy production, and precursor biosynthesis. The rheostat-like mechanism of metabolite-mediated control of flux partitioning demonstrates the importance of allosteric regulation during metabolic steady-state. The sensitivity of this regulatory mechanism to perturbations presents a potentially attractive target for chemotherapy. PMID:27555519

  1. A rheostat mechanism governs the bifurcation of carbon flux in mycobacteria

    PubMed Central

    Murima, Paul; Zimmermann, Michael; Chopra, Tarun; Pojer, Florence; Fonti, Giulia; Dal Peraro, Matteo; Alonso, Sylvie; Sauer, Uwe; Pethe, Kevin; McKinney, John D.

    2016-01-01

    Fatty acid metabolism is an important feature of the pathogenicity of Mycobacterium tuberculosis during infection. Consumption of fatty acids requires regulation of carbon flux bifurcation between the oxidative TCA cycle and the glyoxylate shunt. In Escherichia coli, flux bifurcation is regulated by phosphorylation-mediated inhibition of isocitrate dehydrogenase (ICD), a paradigmatic example of post-translational mechanisms governing metabolic fluxes. Here, we demonstrate that, in contrast to E. coli, carbon flux bifurcation in mycobacteria is regulated not by phosphorylation but through metabolic cross-activation of ICD by glyoxylate, which is produced by the glyoxylate shunt enzyme isocitrate lyase (ICL). This regulatory circuit maintains stable partitioning of fluxes, thus ensuring a balance between anaplerosis, energy production, and precursor biosynthesis. The rheostat-like mechanism of metabolite-mediated control of flux partitioning demonstrates the importance of allosteric regulation during metabolic steady-state. The sensitivity of this regulatory mechanism to perturbations presents a potentially attractive target for chemotherapy. PMID:27555519

  2. Neoclassical Angular Momentum Flux Revisited

    NASA Astrophysics Data System (ADS)

    Wong, S. K.; Chan, V. S.

    2004-11-01

    The toroidal angular momentum flux in neoclassical transport theory of small rotations depends on the second order (in ion poloidal gyroradius over plasma scale length) ion distribution function. Owing to the complexity of the calculation, the result obtained a long time ago for circular cross-section tokamak plasmas in the banana regime [M.N. Rosenbluth, et al., Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1971), Vol. 1, p. 495] has never been reproduced. Using a representation of the angular momentum flux based on the solution of an adjoint equation to the usual linearized drift kinetic equation, and performing systematically a large-aspect-ratio expansion, we have obtained the flux for flux surfaces of arbitrary shape. We have found the same analytic form for the temperature gradient driven part of the flux, but the overall numerical multiplier is different and has the opposite sign. Implications for rotations in discharges with no apparent momentum input will be discussed.

  3. Designing with null flux coils

    SciTech Connect

    Davey, K.R.

    1997-09-01

    Null flux were suggested by Danby and Powell in the late 1960`s as a useful means for realizing induced lift with little drag. As an array of alternating magnets is translated past a set of null flux coils, the currents induced in these coils act to vertically center the magnets on those coils. At present, one Japanese MAGLEV system company and two American-based companies are employing either null flux or flux eliminating coils in their design for high speed magnetically levitated transportation. The principle question addressed in paper is: what is the proper choice of coil length to magnet length in a null flux system? A generic analysis in the time and frequency domain is laid out with the intent of showing the optimal design specification in terms of coil parameters.

  4. Flux growth utilizing the reaction between flux and crucible

    NASA Astrophysics Data System (ADS)

    Yan, J.-Q.

    2015-04-01

    Flux growth involves dissolving the components of the target compound in an appropriate flux at high temperatures and then crystallizing under supersaturation controlled by cooling or evaporating the flux. A refractory crucible is generally used to contain the high temperature melt. The reaction between the melt and crucible materials can modify the composition of the melt, which typically results in growth failure, or contaminates the crystals. Thus one principle in designing a flux growth is to select suitable flux and crucible materials thus to avoid any reaction between them. In this paper, we review two cases of flux growth in which the reaction between flux and Al2O3 crucible tunes the oxygen content in the melt and helps the crystallization of desired compositions. For the case of La5Pb3O, the Al2O3 crucible oxidizes La to form a passivating La2O3 layer which not only prevents further oxidization of La in the melt but also provides [O] to the melt. For the case of La0.4Na0.6Fe2As2, it is believed that the Al2O3 crucible reacts with NaAsO2 and the reaction consumes oxygen in the melt thus maintaining an oxygen-free environment.

  5. PHLUX: Photographic Flux Tools for Solar Glare and Flux

    2010-12-02

    A web-based tool to a) analytically and empirically quantify glare from reflected light and determine the potential impact (e.g., temporary flash blindness, retinal burn), and b) produce flux maps for central receivers. The tool accepts RAW digital photographs of the glare source (for hazard assessment) or the receiver (for flux mapping), as well as a photograph of the sun for intensity and size scaling. For glare hazard assessment, the tool determines the retinal irradiance (W/cm2)more » and subtended source angle for an observer and plots the glare source on a hazard spectrum (i.e., low-potential for flash blindness impact, potential for flash blindness impact, retinal burn). For flux mapping, the tool provides a colored map of the receiver scaled by incident solar flux (W/m2) and unwraps the physical dimensions of the receiver while accounting for the perspective of the photographer (e.g., for a flux map of a cylindrical receiver, the horizontal axis denotes receiver angle in degrees and the vertical axis denotes vertical position in meters; for a flat panel receiver, the horizontal axis denotes horizontal position in meters and the vertical axis denotes vertical position in meters). The flux mapping capability also allows the user to specify transects along which the program plots incident solar flux on the receiver.« less

  6. Flux growth utilizing the reaction between flux and crucible

    DOE PAGESBeta

    Yan, J. -Q.

    2015-01-22

    Flux growth involves dissolving the components of the target compound in an appropriate flux at high temperatures and then crystallizing under supersaturation controlled by cooling or evaporating the flux. A refractory crucible is generally used to contain the high temperature melt. Moreover, the reaction between the melt and crucible materials can modify the composition of the melt, which typically results in growth failure, or contaminates the crystals. Thus one principle in designing a flux growth is to select suitable flux and crucible materials thus to avoid any reaction between them. In this paper, we review two cases of flux growthmore » in which the reaction between flux and Al2O3 crucible tunes the oxygen content in the melt and helps the crystallization of desired compositions. For the case of La5Pb3O, the Al2O3 crucible oxidizes La to form a passivating La2O3 layer which not only prevents further oxidization of La in the melt but also provides [O] to the melt. Finally, in the case of La0.4Na0.6Fe2As2, it is believed that the Al2O3 crucible reacts with NaAsO2 and the reaction consumes oxygen in the melt thus maintaining an oxygen-free environment.« less

  7. PHLUX: Photographic Flux Tools for Solar Glare and Flux

    SciTech Connect

    2010-12-02

    A web-based tool to a) analytically and empirically quantify glare from reflected light and determine the potential impact (e.g., temporary flash blindness, retinal burn), and b) produce flux maps for central receivers. The tool accepts RAW digital photographs of the glare source (for hazard assessment) or the receiver (for flux mapping), as well as a photograph of the sun for intensity and size scaling. For glare hazard assessment, the tool determines the retinal irradiance (W/cm2) and subtended source angle for an observer and plots the glare source on a hazard spectrum (i.e., low-potential for flash blindness impact, potential for flash blindness impact, retinal burn). For flux mapping, the tool provides a colored map of the receiver scaled by incident solar flux (W/m2) and unwraps the physical dimensions of the receiver while accounting for the perspective of the photographer (e.g., for a flux map of a cylindrical receiver, the horizontal axis denotes receiver angle in degrees and the vertical axis denotes vertical position in meters; for a flat panel receiver, the horizontal axis denotes horizontal position in meters and the vertical axis denotes vertical position in meters). The flux mapping capability also allows the user to specify transects along which the program plots incident solar flux on the receiver.

  8. Altered Skeletal Muscle Fatty Acid Handling in Subjects with Impaired Glucose Tolerance as Compared to Impaired Fasting Glucose.

    PubMed

    Goossens, Gijs H; Moors, Chantalle C M; Jocken, Johan W E; van der Zijl, Nynke J; Jans, Anneke; Konings, Ellen; Diamant, Michaela; Blaak, Ellen E

    2016-03-01

    Altered skeletal muscle fatty acid (FA) metabolism contributes to insulin resistance. Here, we compared skeletal muscle FA handling between subjects with impaired fasting glucose (IFG; n = 12 (7 males)) and impaired glucose tolerance (IGT; n = 14 (7 males)) by measuring arterio-venous concentration differences across forearm muscle. [²H₂]-palmitate was infused intravenously, labeling circulating endogenous triacylglycerol (TAG) and free fatty acids (FFA), whereas [U-(13)C]-palmitate was incorporated in a high-fat mixed-meal, labeling chylomicron-TAG. Skeletal muscle biopsies were taken to determine muscle TAG, diacylglycerol (DAG), FFA, and phospholipid content, their fractional synthetic rate (FSR) and degree of saturation, and gene expression. Insulin sensitivity was assessed using a hyperinsulinemic-euglycemic clamp. Net skeletal muscle glucose uptake was lower (p = 0.018) and peripheral insulin sensitivity tended to be reduced (p = 0.064) in IGT as compared to IFG subjects. Furthermore, IGT showed higher skeletal muscle extraction of VLDL-TAG (p = 0.043), higher muscle TAG content (p = 0.025), higher saturation of FFA (p = 0.004), lower saturation of TAG (p = 0.017) and a tendency towards a lower TAG FSR (p = 0.073) and a lower saturation of DAG (p = 0.059) versus IFG individuals. Muscle oxidative gene expression was lower in IGT subjects. In conclusion, increased liver-derived TAG extraction and reduced lipid turnover of saturated FA, rather than DAG content, in skeletal muscle accompany the more pronounced insulin resistance in IGT versus IFG subjects. PMID:26985905

  9. Removal of free fatty acid in Palm Fatty Acid Distillate using sulfonated carbon catalyst derived from biomass wastefor biodiesel production

    NASA Astrophysics Data System (ADS)

    Hidayat, Arif; Rochmadi; Wijaya, Karna; Budiman, Arief

    2016-01-01

    In this research, the esterification of PFAD using the sulfonatedcoconut shell biochar catalyst was studied. Carbon solid catalysts were prepared by a sulfonation of carbonized coconut shells. The performances of the catalysts were evaluated in terms of the reaction temperatures, the molar ratios of methanol to PFAD, the catalyst loading and the reaction times. The reusability of the solid acid carbon catalysts was also studied in this work. The results indicated that the FFA conversion was significantly increased with increasing catalyst loading and reaction times. It can be concluded that the optimal conditions were an PFAD to methanol molar ratio of 1:12, the amount of catalyst of 10%w, and reaction temperature of 60oC.At this optimum condition, the conversion to biodieselreached 88%.

  10. The effect of hyperglycemia on the pharmacokinetics of valproic acid studied by high-performance liquid chromatography with electrochemical detection.

    PubMed

    Kotani, Akira; Kotani, Tomoko; Ishii, Nana; Hakamata, Hideki; Kusu, Fumiyo

    2014-08-01

    The effects of hyperglycemia on the pharmacokinetics of valproic acid (VPA) were examined by time-concentration profiles of plasma VPA accompanied with blood glucose (BG) changing. In addition, time-concentration profiles of plasma free fatty acids (FFAs) were also obtained to examine the interaction between VPA and FFAs in vivo. For the experiments in vivo, normal rats, given multiple doses of maltose orally, and diabetic rats, which were made to maintain hyperglycemia, were used. Plasma VPA and FFA were determined by high-performance liquid chromatography with electrochemical detection (HPLC-ECD) systems based on the reduction of quinone for the selective determination of acids, respectively. BG was determined by pocket-size glucose meter. The maximum plasma concentrations (Cmax) of VPA in normal rats given multiple doses of maltose orally and in diabetic rats were remarkably decreased in comparison with those in the control rats. From the present study, it was shown that the metabolism of plasma VPA is accelerated under hyperglycemia. Moreover, we also found that VPA was preferentially metabolized in comparison with the plasma FFA in vivo. PMID:24814995

  11. Susceptibility of Helicobacter pylori to bactericidal properties of medium-chain monoglycerides and free fatty acids.

    PubMed Central

    Petschow, B W; Batema, R P; Ford, L L

    1996-01-01

    Previous studies have shown that various short- and medium-chain free fatty acids (FFAs) and their corresponding monoacylglycerol esters (MGs) have antibacterial activity in vitro against primarily gram-positive bacteria. More recent studies have also shown that the growth of Helicobacter spp. is inhibited by linoleic acid and arachidonic acid. The purpose of the present study was to evaluate the susceptibility of Helicobacter pylori to the in vitro bactericidal properties of medium-chain MGs and FFAs. Incubation of H. pylori with saturated MGs, ranging in carbon chain length from C10:0 to C14:0, at 1 mM caused a 4-log-unit or greater reduction in the number of viable bacteria after exposure for 1 h. Lower levels of bactericidal activity were observed with C9:0, C15:0, and C16:0 MGs. In contrast, lauric acid (C12:0) was the only medium-chain saturated FFA with bactericidal activity against H. pylori. The MGs and FFAs were bactericidal after incubation for as little as 15 min at neutral or acidic pHs. Higher levels of MGs and FFAs were required for bactericidal activity in the presence of higher amounts of protein in liquid diets. We also found that the frequency of spontaneous development of resistance by H. pylori was higher for metronidazole and tetracycline (10(-5) to 10(-6)) than for C10:0 MG, C12:0 MG, and C12:0 FFA (< 10(-8)). Collectively, our data demonstrate that H. pylori is rapidly inactivated by medium-chain MGs and lauric acid and exhibits a relatively low frequency of spontaneous development of resistance to the bactericidal activity of MGs. Further studies are needed to establish whether MGs may be useful either alone or with other known therapeutic agents in the management of H. pylori infections in humans. PMID:8834870

  12. Monte Carlo surface flux tallies

    SciTech Connect

    Favorite, Jeffrey A

    2010-11-19

    Particle fluxes on surfaces are difficult to calculate with Monte Carlo codes because the score requires a division by the surface-crossing angle cosine, and grazing angles lead to inaccuracies. We revisit the standard practice of dividing by half of a cosine 'cutoff' for particles whose surface-crossing cosines are below the cutoff. The theory behind this approximation is sound, but the application of the theory to all possible situations does not account for two implicit assumptions: (1) the grazing band must be symmetric about 0, and (2) a single linear expansion for the angular flux must be applied in the entire grazing band. These assumptions are violated in common circumstances; for example, for separate in-going and out-going flux tallies on internal surfaces, and for out-going flux tallies on external surfaces. In some situations, dividing by two-thirds of the cosine cutoff is more appropriate. If users were able to control both the cosine cutoff and the substitute value, they could use these parameters to make accurate surface flux tallies. The procedure is demonstrated in a test problem in which Monte Carlo surface fluxes in cosine bins are converted to angular fluxes and compared with the results of a discrete ordinates calculation.

  13. Magnetospheric-ionospheric Poynting flux

    NASA Technical Reports Server (NTRS)

    Thayer, Jeffrey P.

    1994-01-01

    Over the past three years of funding SRI, in collaboration with the University of Texas at Dallas, has been involved in determining the total electromagnetic energy flux into the upper atmosphere from DE-B electric and magnetic field measurements and modeling the electromagnetic energy flux at high latitudes, taking into account the coupled magnetosphere-ionosphere system. This effort has been very successful in establishing the DC Poynting flux as a fundamental quantity in describing the coupling of electromagnetic energy between the magnetosphere and ionosphere. The DE-B satellite electric and magnetic field measurements were carefully scrutinized to provide, for the first time, a large data set of DC, field-aligned, Poynting flux measurement. Investigations describing the field-aligned Poynting flux observations from DE-B orbits under specific geomagnetic conditions and from many orbits were conducted to provide a statistical average of the Poynting flux distribution over the polar cap. The theoretical modeling effort has provided insight into the observations by formulating the connection between Poynting's theorem and the electromagnetic energy conversion processes that occur in the ionosphere. Modeling and evaluation of these processes has helped interpret the satellite observations of the DC Poynting flux and improved our understanding of the coupling between the ionosphere and magnetosphere.

  14. Chloride flux in phagocytes.

    PubMed

    Wang, Guoshun

    2016-09-01

    Phagocytes, such as neutrophils and macrophages, engulf microbes into phagosomes and launch chemical attacks to kill and degrade them. Such a critical innate immune function necessitates ion participation. Chloride, the most abundant anion in the human body, is an indispensable constituent of the myeloperoxidase (MPO)-H2 O2 -halide system that produces the potent microbicide hypochlorous acid (HOCl). It also serves as a balancing ion to set membrane potentials, optimize cytosolic and phagosomal pH, and regulate phagosomal enzymatic activities. Deficient supply of this anion to or defective attainment of this anion by phagocytes is linked to innate immune defects. However, how phagocytes acquire chloride from their residing environment especially when they are deployed to epithelium-lined lumens, and how chloride is intracellularly transported to phagosomes remain largely unknown. This review article will provide an overview of chloride protein carriers, potential mechanisms for phagocytic chloride preservation and acquisition, intracellular chloride supply to phagosomes for oxidant production, and methods to measure chloride levels in phagocytes and their phagosomes. PMID:27558337

  15. The Effects of α-Lipoic Acid on Liver Oxidative Stress and Free Fatty Acid Composition in Methionine–Choline Deficient Diet-Induced NAFLD

    PubMed Central

    Stanković, Milena N.; Mladenović, Dušan; Ninković, Milica; Ðuričić, Ivana; Šobajić, Slađana; Jorgačević, Bojan; de Luka, Silvio; Vukicevic, Rada Jesic

    2014-01-01

    Abstract Development of nonalcoholic fatty liver disease (NAFLD) occurs through initial steatosis and subsequent oxidative stress. The aim of this study was to examine the effects of α-lipoic acid (LA) on methionine–choline deficient (MCD) diet-induced NAFLD in mice. Male C57BL/6 mice (n=21) were divided into three groups (n=7 per group): (1) control fed with standard chow, (2) MCD2 group—fed with MCD diet for 2 weeks, and (3) MCD2+LA group—2 weeks on MCD receiving LA i.p. 100 mg/kg/day. After the treatment, liver samples were taken for pathohistology, oxidative stress parameters, antioxidative enzymes, and liver free fatty acid (FFA) composition. Mild microvesicular hepatic steatosis was found in MCD2 group, while it was reduced to single fat droplets evident in MCD2+LA group. Lipid peroxidation and nitrosative stress were increased by MCD diet, while LA administration induced a decrease in liver malondialdehyde and nitrates+nitrites level. Similary, LA improved liver antioxidative capacity by increasing total superoxide dismutase (tSOD), manganese SOD (MnSOD), and copper/zinc-SOD (Cu/ZnSOD) activity as well as glutathione (GSH) content. Liver FFA profile has shown a significant decrease in saturated acids, arachidonic, and docosahexaenoic acid (DHA), while LA treatment increased their proportions. It can be concluded that LA ameliorates lipid peroxidation and nitrosative stress in MCD diet-induced hepatic steatosis through an increase in SOD activity and GSH level. In addition, LA increases the proportion of palmitic, stearic, arachidonic, and DHA in the fatty liver. An increase in DHA may be a potential mechanism of anti-inflammatory and antioxidant effects of LA in MCD diet-induced NAFLD. PMID:24325457

  16. Solar flux and its variations

    NASA Technical Reports Server (NTRS)

    Smith, E. V. P.; Gottlieb, D. M.

    1975-01-01

    Data are presented on the solar irradiance as derived from a number of sources. An attempt was made to bring these data onto a uniform scale. Summation of fluxes at all wavelengths yields a figure of 1357.826 for the solar constant. Estimates are made of the solar flux variations due to flares, active regions (slowly varying component), 27-day period, and the 11-yr cycle. Solar activity does not produce a significant variation in the value of the solar constant. Variations in the X-ray and EUV portions of the solar flux may be several orders of magnitude during solar activity, especially at times of major flares. It is established that these short wavelength flux enhancements cause significant changes in the terrestrial ionosphere.

  17. Distribution and flux of micrometeoroids

    NASA Technical Reports Server (NTRS)

    Morrison, D. A.; Zinner, E.

    1977-01-01

    The mass distribution, flux, and distribution in space of the micrometeoroid complex at 1 AU are estimated on the basis of data from Apollo 17 rocks and recent calibrations of solar-flare track-production rates. It is found that the size frequency distribution of microcraters on lunar rocks suggests a bimodal mass distribution of micrometeoroids, but the precise form of the curve requires further definition, particularly insofar as the degree of depletion of particles producing craters 10 to 100 microns in diameter is concerned. Variations in slope with crater-diameter or particle-mass increments are shown to indicate that different processes affect one or more particle populations. Fluxes corresponding to varied lunar surface orientation and residence time are calculated, but no striking difference is observed between the flux of submicron-diameter particles with orbits in the plane of the ecliptic and fluxes of particles with orbits normal to the plane in the solar apex direction.

  18. Conical electromagnetic radiation flux concentrator

    NASA Technical Reports Server (NTRS)

    Miller, E. R.

    1972-01-01

    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  19. Plasmoids as magnetic flux ropes

    SciTech Connect

    Moldwin, M.B.; Hughes, W.J. )

    1991-08-01

    Observational constraints on the magnetic topology and orientation of plasmoids is examined using a magnetic field model. The authors develop a magnetic flux rope model to examine whether principal axis analysis (PAA) of magnetometer signatures from a single satellite pass is sufficient to determine the magnetic topology of plasmoids and if plasmoid observations are best explained by the flux rope, closed loop, or large-amplitude wave picture. Satellite data are simulated by extracting the magnetic field along a path through the model of a magnetic flux rope. They then examine the results using PAA. They find that the principal axis directions (and therefore the interpretation of structure orientation) is highly dependent on several parameters including the satellite trajectory through the structure. Because of this they conclude that PAA of magnetometer data from a single satellite pass is insufficient to differentiate between magnetic closed loop and flux rope models. They also compare the model results to ISEE 3 magnetometer data of plasmoid events in various coordinate frames including principal axis and geocentric solar magnetospheric. They find that previously identified plasmoid events that have been explained as closed loop structures can also be modeled as flux ropes. They also searched the literature for previously reported flux rope and closed loop plasmoid events to examine if these structures had any similarities and/or differences. The results of the modeling efforts and examination of both flux rope and plasmoid events lead them to favor the flux rope model of plasmoid formation, as it is better able to unify the observations of various magnetic structures observed by ISEE 3.

  20. Flux tubes at finite temperature

    NASA Astrophysics Data System (ADS)

    Cea, Paolo; Cosmai, Leonardo; Cuteri, Francesca; Papa, Alessandro

    2016-06-01

    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU (3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm˜eq 1.6/√{σ } and the temperature is increased towards and above the deconfinement temperature T c , the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube "evaporation" above T c has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.

  1. Flux growth utilizing the reaction between flux and crucible

    SciTech Connect

    Yan, J. -Q.

    2015-01-22

    Flux growth involves dissolving the components of the target compound in an appropriate flux at high temperatures and then crystallizing under supersaturation controlled by cooling or evaporating the flux. A refractory crucible is generally used to contain the high temperature melt. Moreover, the reaction between the melt and crucible materials can modify the composition of the melt, which typically results in growth failure, or contaminates the crystals. Thus one principle in designing a flux growth is to select suitable flux and crucible materials thus to avoid any reaction between them. In this paper, we review two cases of flux growth in which the reaction between flux and Al2O3 crucible tunes the oxygen content in the melt and helps the crystallization of desired compositions. For the case of La5Pb3O, the Al2O3 crucible oxidizes La to form a passivating La2O3 layer which not only prevents further oxidization of La in the melt but also provides [O] to the melt. Finally, in the case of La0.4Na0.6Fe2As2, it is believed that the Al2O3 crucible reacts with NaAsO2 and the reaction consumes oxygen in the melt thus maintaining an oxygen-free environment.

  2. Production of biodiesel from vegetable oil and microalgae by fatty acid extraction and enzymatic esterification.

    PubMed

    Castillo López, Beatriz; Esteban Cerdán, Luis; Robles Medina, Alfonso; Navarro López, Elvira; Martín Valverde, Lorena; Hita Peña, Estrella; González Moreno, Pedro A; Molina Grima, Emilio

    2015-06-01

    The aim of this work was to obtain biodiesel (methyl esters) from the saponifiable lipids (SLs) fraction of the microalga Nannochloropsis gaditana, whose biomass dry weight contains 12.1 wt% of these lipids. SLs were extracted from the microalga as free fatty acids (FFAs) for subsequent transformation to methyl esters (biodiesel) by enzymatic esterification. Extraction as FFAs rather than as SLs allows them to be obtained with higher purity. Microalgal FFAs were obtained by direct saponification of lipids in the biomass and subsequent extraction-purification with hexane. Esterification of FFAs with methanol was catalysed by lipase Novozym 435 from Candida antarctica. Stability studies of this lipase in the operational conditions showed that the esterification degree (ED) attained with the same batch of lipase remained constant over six reaction cycles (36 h total reaction time). The optimal conditions attained for 4 g of FFAs were 25°C, 200 rpm, methanol/FFA molar ratio of 1.5:1, Novozym 435/FFA ratio of 0.025:1 w/w and 4 h reaction time. In these conditions the ED attained was 92.6%, producing a biodiesel with 83 wt% purity from microalgal FFAs. Several experimental scales were tested (from 4 to 40 g FFAs), and in all cases similar EDs were obtained. PMID:25575971

  3. A Peptide-Based Method for 13C Metabolic Flux Analysis in Microbial Communities

    PubMed Central

    Ghosh, Amit; Nilmeier, Jerome; Weaver, Daniel; Adams, Paul D.; Keasling, Jay D.; Mukhopadhyay, Aindrila; Petzold, Christopher J.; Martín, Héctor García

    2014-01-01

    The study of intracellular metabolic fluxes and inter-species metabolite exchange for microbial communities is of crucial importance to understand and predict their behaviour. The most authoritative method of measuring intracellular fluxes, 13C Metabolic Flux Analysis (13C MFA), uses the labeling pattern obtained from metabolites (typically amino acids) during 13C labeling experiments to derive intracellular fluxes. However, these metabolite labeling patterns cannot easily be obtained for each of the members of the community. Here we propose a new type of 13C MFA that infers fluxes based on peptide labeling, instead of amino acid labeling. The advantage of this method resides in the fact that the peptide sequence can be used to identify the microbial species it originates from and, simultaneously, the peptide labeling can be used to infer intracellular metabolic fluxes. Peptide identity and labeling patterns can be obtained in a high-throughput manner from modern proteomics techniques. We show that, using this method, it is theoretically possible to recover intracellular metabolic fluxes in the same way as through the standard amino acid based 13C MFA, and quantify the amount of information lost as a consequence of using peptides instead of amino acids. We show that by using a relatively small number of peptides we can counter this information loss. We computationally tested this method with a well-characterized simple microbial community consisting of two species. PMID:25188426

  4. Demonstration of HNO3 Eddy Flux Measurements at the Boulder Atmospheric Observatory Using Active Passivation

    NASA Astrophysics Data System (ADS)

    Roscioli, J. R.; Herndon, S. C.; Zahniser, M. S.; Nelson, D. D.; Zaragoza, J.; Pollack, I. B.; Fischer, E. V.

    2015-12-01

    Eddy flux measurements of "sticky" molecules have historically proven difficult due to strong interactions with instrument surfaces. A novel approach has been developed to improve these response times, enabling flux measurements of nitric acid (HNO3) and and ammonia (NH3). Deliberate addition of the vapor of perfluorinated acids and bases into a sample stream serves to eject existing surface-bound sample molecules and passivate instrument surfaces. HNO3 response times for an Aerodyne quantum cascade laser absorption spectrometer (QCLAS) improve by a factor of 60-fold when actively passivating. This approach was used during field measurements of HNO3 fluxes at the Boulder Atmospheric Observatory, where an actively passivated inertial inlet at 8 m height yielded HNO3 deposition fluxes of 0.5 - 2 nmol/m2/sec. The dependence of the deposition flux upon urban vs rural outflow is discussed.

  5. Flux flow and flux dynamics in high-Tc superconductors

    NASA Technical Reports Server (NTRS)

    Bennett, L. H.; Turchinskaya, M.; Swartzendruber, L. J.; Roitburd, A.; Lundy, D.; Ritter, J.; Kaiser, D. L.

    1991-01-01

    Because high temperature superconductors, including BYCO and BSSCO, are type 2 superconductors with relatively low H(sub c 1) values and high H(sub c 2) values, they will be in a critical state for many of their applications. In the critical state, with the applied field between H(sub c 1) and H(sub c 2), flux lines have penetrated the material and can form a flux lattice and can be pinned by structural defects, chemical inhomogeneities, and impurities. A detailed knowledge of how flux penetrates the material and its behavior under the influence of applied fields and current flow, and the effect of material processing on these properties, is required in order to apply, and to improve the properties of these superconductors. When the applied field is changed rapidly, the time dependence of flux change can be divided into three regions, an initial region which occurs very rapidly, a second region in which the magnetization has a 1n(t) behavior, and a saturation region at very long times. A critical field is defined for depinning, H(sub c,p) as that field at which the hysteresis loop changes from irreversible to reversible. As a function of temperature, it is found that H(sub c,p) is well described by a power law with an exponent between 1.5 and 2.5. The behavior of H(sub c,p) for various materials and its relationship to flux flow and flux dynamics are discussed.

  6. NITRIC ACID PICKLING PROCESS

    DOEpatents

    Boller, E.R.; Eubank, L.D.

    1958-08-19

    An improved process is described for the treatment of metallic uranium surfaces preparatory to being given hot dip coatings. The process consists in first pickling the uraniunn surInce with aqueous 50% to 70% nitric acid, at 60 to 70 deg C, for about 5 minutes, rinsing the acid solution from the uranium article, promptly drying and then passing it through a molten alkali-metal halide flux consisting of 42% LiCl, 53% KCla and 5% NaCl into a molten metal bath consisting of 85 parts by weight of zinc and 15 parts by weight of aluminum

  7. Skeletal muscle fatty acid handling in insulin resistant men.

    PubMed

    van Hees, Anneke M J; Jans, Anneke; Hul, Gabby B; Roche, Helen M; Saris, Wim H M; Blaak, Ellen E

    2011-07-01

    Disturbances in skeletal muscle lipid metabolism may precede or contribute to the development of whole body insulin resistance. In this study, we examined fasting and postprandial skeletal muscle fatty acid (FA) handling in insulin resistant (IR) men. Thirty men with the metabolic syndrome (MetS) (National Cholesterol Education Program-Adult Treatment Panel III) were included in this sub-study to the LIPGENE study, and divided in two groups (IR and control) based on the median of insulin sensitivity (S(I) = 2.06 (mU/l(-1))·min(-1)·10(-4)). Fasting and postprandial skeletal muscle FA handling were examined by combining the forearm balance technique with stable isotopes of palmitate. [(2)H(2)]-palmitate was infused intravenously to label endogenous triacylglycerol (TAG) and free FAs (FFAs) in the circulation and [U-(13)C]-palmitate was incorporated in a high-fat mixed meal (2.6 MJ, 61 E% fat) to label chylomicron-TAG. Muscle biopsies were taken to determine muscle TAG, diacylglycerol (DAG), FFA, and phospholipid (PL) content, their fractional synthetic rates (FSRs) and degree of saturation, as well as messenger RNA (mRNA) expression of genes involved in lipid metabolism. In the first 2 h after meal consumption, forearm muscle [(2)H(2)]-labeled TAG extraction was higher in IR vs. control (P = 0.05). Fasting percentage saturation of muscle DAG was higher in IR vs. control (P = 0.016). No differences were observed for intramuscular TAG, DAG, FFA, and PL content, FSR, and muscle mRNA expression. In conclusion, increased muscle (hepatically derived) TAG extraction during postprandial conditions and increased saturation of intramuscular DAG are associated with insulin resistance, suggesting that disturbances in skeletal muscle FA handling could play a role in the development of whole body insulin resistance and type 2 diabetes. PMID:21331063

  8. Increase of betulinic acid production in Saccharomyces cerevisiae by balancing fatty acids and betulinic acid forming pathways.

    PubMed

    Li, Jing; Zhang, Yansheng

    2014-04-01

    Betulinic acid is a plant-based triterpenoid that has been recognized for its antitumor and anti-HIV activities. The level of betulinic acid in its natural hosts is extremely low. In the present study, we constructed betulinic acid biosynthetic pathway in Saccharomyces cerevisiae by metabolic engineering. Given the betulinic acid forming pathways sharing the common substrate acetyl-CoA with fatty acid synthesis, the metabolic fluxes between the two pathways were varied by changing gene expressions, and their effects on betulinic acid production were investigated. We constructed nine S. cerevisiae strains representing nine combinations of the flux distributions between betulinic acid and fatty acid pathways. Our results demonstrated that it was possible to improve the betulinic acid production in S. cerevisiae while keeping a desirable growth phenotype by optimally balancing the carbon fluxes of the two pathways. Through modulating the expressions of the key genes on betulinic acid and fatty acid pathways, the difference in betulinic acid yield varied largely in the range of 0.01-1.92 mg L(-1) OD(-1). The metabolic engineering approach used in this study could be extended for synthesizing other triterpenoids in S. cerevisiae. PMID:24389702

  9. Amino acids

    MedlinePlus

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  10. Double-nuclide study of the myocardium using 201Tl and 123I-labeled fatty acids in non-ischemic myocardial diseases.

    PubMed

    Knapp, W H; Vyska, K; Machulla, H J; Notohamiprodjo, G; Schmidt, U; Knust, E J; Gleichmann, U

    1988-06-01

    Metabolic impairment and perfusion abnormalities are known to occur in hypertensive heart disease (HHD) and in cardiomyopathies. Free fatty acid (FFA) extraction is severely inhibited in a number of pathobiochemical reactions. This parameter was assessed using the radiolabeled FFA analogue 123I-(p-iodo-phenyl-)-pentadecanoic acid (IPPA) and 201Tl as perfusion marker, both of them injected at maximal physical workload. The regional extraction fraction of IPPA (IPPA-EF) was estimated by relating the regional IPPA and 201Tl uptake to each other. In HHD (normal coronary arteries) with posterior wall thickness less than or equal to 12 mm IPPA-EF was 77 +/- 18% (SD) in septum and 92 +/- 17% in the posterolateral wall (N = 13), with thickness of greater than 12 mm 60 +/- 23% in septum and 61 +/- 20% in the posterolateral wall (N = 8) when compared with IPPA-EF in normal subjects (= 100%, N = 9). In hypertrophic cardiomyopathy (HCM) IPPA-EF averaged 51 +/- 20% in septum and 87 +/- 10% in the posterolateral wall (N = 11). In these patient groups no systematic regional changes in 201TI uptake were observed. In dilated cardiomyopathy (DCM) both IPPA-EF and 201Tl uptake showed distinct regional variations and a great interindividual variability with a mean IPPA-EF reduction of 12% (N = 9). Thus, IPPA uptake in primarily non-ischemic myocardial disease may already be compromised when 201Tl uptake is unchanged. The double-nuclide method for IPPA-EF determination allows to eliminate the influence of flow in FFA imaging and enhances the potential of scintigraphy in the differential diagnosis of HHD versus coronary artery disease. PMID:3405780

  11. Cyclosporine A and palmitic acid treatment synergistically induce cytotoxicity in HepG2 cells

    SciTech Connect

    Luo, Yi Rana, Payal; Will, Yvonne

    2012-06-01

    Immunosuppressant cyclosporine A (CsA) treatment can cause severe side effects. Patients taking immunosuppressant after organ transplantation often display hyperlipidemia and obesity. Elevated levels of free fatty acids have been linked to the etiology of metabolic syndromes, nonalcoholic fatty liver and steatohepatitis. The contribution of free fatty acids to CsA-induced toxicity is not known. In this study we explored the effect of palmitic acid on CsA-induced toxicity in HepG2 cells. CsA by itself at therapeutic exposure levels did not induce detectible cytotoxicity in HepG2 cells. Co-treatment of palmitic acid and CsA resulted in a dose dependent increase in cytotoxicity, suggesting that fatty acid could sensitize cells to CsA-induced cytotoxicity at the therapeutic doses of CsA. A synergized induction of caspase-3/7 activity was also observed, indicating that apoptosis may contribute to the cytotoxicity. We demonstrated that CsA reduced cellular oxygen consumption which was further exacerbated by palmitic acid, implicating that impaired mitochondrial respiration might be an underlying mechanism for the enhanced toxicity. Inhibition of c-Jun N-terminal kinase (JNK) attenuated palmitic acid and CsA induced toxicity, suggesting that JNK activation plays an important role in mediating the enhanced palmitic acid/CsA-induced toxicity. Our data suggest that elevated FFA levels, especially saturated FFA such as palmitic acid, may be predisposing factors for CsA toxicity, and patients with underlying diseases that would elevate free fatty acids may be susceptible to CsA-induced toxicity. Furthermore, hyperlipidemia/obesity resulting from immunosuppressive therapy may aggravate CsA-induced toxicity and worsen the outcome in transplant patients. -- Highlights: ► Palmitic acid and cyclosporine (CsA) synergistically increased cytotoxicity. ► The impairment of mitochondrial functions may contribute to the enhanced toxicity. ► Inhibition of JNK activity attenuated

  12. Measurement of Myocardial Fatty Acid Esterification Using [1-11C]Palmitate and PET: Comparison with Direct Measurements of Myocardial Triglyceride Synthesis

    PubMed Central

    Coggan, Andrew R.; Kisrieva-Ware, Zulfia; Dence, Carmen S.; Eisenbeis, Paul; Gropler, Robert J.; Herrero, Pilar

    2010-01-01

    The purpose of the present study was to assess the accuracy of non-invasive estimates of the rate of myocardial fatty acid esterification (MFAE) obtained using positron emission tomography (PET). Methods Sixteen dogs were studied after an overnight fast (FAST), during a euglycemic hyperinsulinemic clamp (CLAMP), or during infusion of Intralipid (IL) or IL plus dobutamine (IL/DOB) (n=4/group). The rate of MFAE was quantified using a bolus injection of [1-11C]palmitate and compartmental modeling as described by Bergmann et al.3 and compared to the rate of triglyceride (TG) synthesis measured directly using a continuous infusion of [1-13C]palmitate and tissue sampling. Results Across groups, mean plasma free fatty acid (FFA) concentration varied ~20-fold, with this variation in FFA availability accompanied by a ~20-fold range in directly-measured TG synthesis (i.e., from 7±1 nmol/min/g in CLAMP to 128±75 nmol/min/g in IL). PET-based estimates of MFAE varied to a similar degree (i.e., from 22±9 nmol/min/g in CLAMP to 543±551 nmol/min/g in IL), and were significantly correlated with TG synthesis (i.e., R=0.77, P<0.001). MFAE, however, was 3- to 4-fold higher than TG synthesis in FAST, CLAMP, and IL, but comparable when cardiac work was increased in IL/DOB, suggesting that MFAE reflects, in part, the incorporation of label into amino acids via TCA cycle exchange reactions (e.g., α-ketoglutarate ↔ glutamate) as well as the synthesis of TG and other lipids. Conclusions Changes in the rate of MFAE as determined using PET and the compartmental model of Bergmann et al.3 parallel changes in the rate of TG synthesis, at least in the basal state. Although such measurements are not as robust as rates of myocardial FFA uptake and oxidation as estimated by the model, this method should still be useful for quantifying acute changes in FFA storage by the heart in various pathophysiological states. PMID:19479313

  13. Surface flux evolution constraints for flux transport dynamos

    NASA Astrophysics Data System (ADS)

    Cameron, R. H.; Schmitt, D.; Jiang, J.; Işık, E.

    2012-06-01

    The surface flux transport (SFT) model of solar magnetic fields involves empirically well-constrained velocity and magnetic fields. The basic evolution of the Sun's large-scale surface magnetic field is well described by this model. The azimuthally averaged evolution of the SFT model can be compared to the surface evolution of the flux transport dynamo (FTD), and the evolution of the SFT model can be used to constrain several near-surface properties of the FTD model. We compared the results of the FTD model with different upper boundary conditions and diffusivity profiles against the results of the SFT model. Among the ingredients of the FTD model, downward pumping of magnetic flux, related to a positive diffusivity gradient, has a significant effect in slowing down the diffusive radial transport of magnetic flux through the solar surface. Provided the pumping was strong enough to give rise to a downflow of a magnetic Reynolds number of 5 in the near-surface boundary layer, the FTD using a vertical boundary condition matches the SFT model based on the average velocities above the boundary layer. The FTD model with a potential field was unable to match the SFT results.

  14. Flux attenuation at NREL's High-Flux Solar Furnace

    NASA Astrophysics Data System (ADS)

    Bingham, Carl E.; Scholl, Kent L.; Lewandowski, Allan A.

    1994-10-01

    The High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) has a faceted primary concentrator and a long focal-length-to-diameter ratio (due to its off-axis design). Each primary facet can be aimed individually to produce different flux distributions at the target plane. Two different types of attenuators are used depending on the flux distribution. A sliding-plate attenuator is used primarily when the facets are aimed at the same target point. The alternate attenuator resembles a venetian blind. Both attenuators are located between the concentrator and the focal point. The venetian-blind attenuator is primarily used to control the levels of sunlight failing on a target when the primary concentrators are not focused to a single point. This paper will demonstrate the problem of using the sliding-plate attenuator with a faceted concentrator when the facets are not aimed at the same target point. We will show that although the alternate attenuator necessarily blocks a certain amount of incoming sunlight, even when fully open, it provides a more even attenuation of the flux for alternate aiming strategies.

  15. Simulations of Magnetic Flux Emergence

    NASA Astrophysics Data System (ADS)

    Stein, Robert; Nordlund, Aake

    Magnetic flux emerges from the solar surface on a wide range of scales. We review recent simulations of both large and small scale flux emergence. In our own simulations, we represent the magnetic flux produced by the global dynamo as uniform, untwisted, horizontal field advected into the simulation domain by supergranule scale inflows at the bottom. Our computational domain extends from the temperature minimum (half a megameter above the visible surface) to 20 Mm below the surface, which is 10% of the depth of the convection zone, but contains 2/3 of its scale heights. We investigate how magnetic flux rises through the upper solar convection zone and emerges through the surface. Convective up-flows and magnetic buoyancy bring field toward the surface. Convective down-flows pin down field and prevent its rise. Most of the field gets pumped downward by the convection, but some field rises to the surface. The convective motions both confine the flux concentrations (without the need for twist) and shred them. This process creates a hierarchy of magnetic loops with smaller loops riding "piggy-back", in a serpentine pattern, on larger loops. As a result, magnetic flux emerges in a mixed polarity, "pepper and salt" pattern. The small loops appear as horizontal field over granules with their vertical legs in the bounding intergranular lanes. The fields are quickly swept into the intergranular lanes. As the larger, parent, flux concentrations reach the surface with their legs rooted in the the downflow boundaries of the underlying, supergranule-scale, convective cells near the bottom of the simulation domain, the surface field counter-streams into separate, opposite polarity concentrations, creating pores and spots. The subsurface magnetic field lines of the pores and spots formed by the magneto-convection (without being imposed as an initial condition) are braided, some tightly, some loosely and they connect in complicated ways to the surrounding field at large depths

  16. Modeling Coronal Jets with FLUX

    NASA Astrophysics Data System (ADS)

    Rachmeler, L. A.; Pariat, E.; Antiochos, S. K.; Deforest, C. E.

    2008-05-01

    We report on a comparative study of coronal jet formation with and without reconnection using two different simulation strategies. Coronal jets are features on the solar surface that appear to have some properties in common with coronal mass ejections, but are less energetic, massive, and broad. Magnetic free energy is built up over time and then suddenly released, which accelerates plasma outward in the form of a coronal jet. We compare results from the ARMS adaptive mesh and FLUX reconnection-less codes to study the role of reconnection in this system. This is the first direct comparison between FLUX and a numerical model with a 3D spatial grid.

  17. High flux solar energy transformation

    DOEpatents

    Winston, Roland; Gleckman, Philip L.; O'Gallagher, Joseph J.

    1991-04-09

    Disclosed are multi-stage systems for high flux transformation of solar energy allowing for uniform solar intensification by a factor of 60,000 suns or more. Preferred systems employ a focusing mirror as a primary concentrative device and a non-imaging concentrator as a secondary concentrative device with concentrative capacities of primary and secondary stages selected to provide for net solar flux intensification of greater than 2000 over 95 percent of the concentration area. Systems of the invention are readily applied as energy sources for laser pumping and in other photothermal energy utilization processes.

  18. High flux solar energy transformation

    DOEpatents

    Winston, R.; Gleckman, P.L.; O'Gallagher, J.J.

    1991-04-09

    Disclosed are multi-stage systems for high flux transformation of solar energy allowing for uniform solar intensification by a factor of 60,000 suns or more. Preferred systems employ a focusing mirror as a primary concentrative device and a non-imaging concentrator as a secondary concentrative device with concentrative capacities of primary and secondary stages selected to provide for net solar flux intensification of greater than 2000 over 95 percent of the concentration area. Systems of the invention are readily applied as energy sources for laser pumping and in other photothermal energy utilization processes. 7 figures.

  19. The production of ω-hydroxy palmitic acid using fatty acid metabolism and cofactor optimization in Escherichia coli.

    PubMed

    Sung, Changmin; Jung, Eunok; Choi, Kwon-Young; Bae, Jin-Hyung; Kim, Minsuk; Kim, Joonwon; Kim, Eun-Jung; Kim, Pyoung Il; Kim, Byung-Gee

    2015-08-01

    Hydroxylated fatty acids (HFAs) are used as important precursors for bulk and fine chemicals in the chemical industry. Here, to overproduce long-chain (C16-C18) fatty acids and hydroxy fatty acid, their biosynthetic pathways including thioesterase (Lreu_0335) from Lactobacillus reuteri DSM20016, β-hydroxyacyl-ACP dehydratase (fabZ) from Escherichia coli, and a P450 system (i.e., CYP153A from Marinobacter aquaeolei VT8 and camA/camB from Pseudomonas putida ATCC17453) were overexpressed. Acyl-CoA synthase (fadD) involved in fatty acid degradation by β-oxidation was also deleted in E. coli BW25113. The engineered E. coli FFA4 strain without the P450 system could produce 503.0 mg/l of palmitic (C16) and 508.4 mg/l of stearic (C18) acids, of which the amounts are ca. 1.6- and 2.3-fold higher than those of the wild type. On the other hand, the E. coli HFA4 strain including the P450 system for ω-hydroxylation could produce 211.7 mg/l of ω-hydroxy palmitic acid, which was 42.1 ± 0.1 % of the generated palmitic acid, indicating that the hydroxylation reaction was the rate-determining step for the HFA production. For the maximum production of ω-hydroxy palmitic acid, NADH, i.e., an essential cofactor for P450 reaction, was overproduced by the integration of NAD(+)-dependent formate dehydrogenase (FDH) from Candida boidinii into E. coli chromosome and the deletion of alcohol dehydrogenase (ADH). Finally, the NADH-level-optimized E. coli strain produced 610 mg/l of ω-hydroxy palmitic acid (ω-HPA), which was almost a threefold increase in its yield compared to the same strain without NADH overproduction. PMID:25957153

  20. Conversion from solvent rinsable fluxes to aqueous rinsable fluxes for hot oil solder leveling

    NASA Astrophysics Data System (ADS)

    1992-03-01

    A water rinsable flux was evaluated for hot oil solder leveling of printed wiring boards. The previously used rosin-activated flux required a solvent containing a chlorinated hydrocarbon for removing the flux residues after soldering. The water rinsable flux requires hot water or a solution of hot detergent for removing flux residues after smoldering. The water rinsable flux produced an acceptable soldered surface. Flux residues were removed by either hot water (120 F) or a solution of hot detergent (120 F).

  1. Relationships among FFA Membership Factors and Vo-Ag Programs in the Eastern FFA Region.

    ERIC Educational Resources Information Center

    Cooper, Elmer L.; Nelson, Clifford L.

    1983-01-01

    This study found that supposed negative influences on Future Farmers of America membership did not prove to be so. There were no direct relationships between membership charges and teacher shortages, use of teachers without full certification, membership costs, or length of teacher contracts. (SK)

  2. Nutritional Signaling via Free Fatty Acid Receptors.

    PubMed

    Miyamoto, Junki; Hasegawa, Sae; Kasubuchi, Mayu; Ichimura, Atsuhiko; Nakajima, Akira; Kimura, Ikuo

    2016-01-01

    Excess energy is stored primarily as triglycerides, which are mobilized when demand for energy arises. Dysfunction of energy balance by excess food intake leads to metabolic diseases, such as obesity and diabetes. Free fatty acids (FFAs) provided by dietary fat are not only important nutrients, but also contribute key physiological functions via FFA receptor (FFAR)-mediated signaling molecules, which depend on FFAs' carbon chain length and the ligand specificity of the receptors. Functional analyses have revealed that FFARs are critical for metabolic functions, such as peptide hormone secretion and inflammation, and contribute to energy homeostasis. In particular, recent studies have shown that the administration of selective agonists of G protein-coupled receptor (GPR) 40 and GPR120 improved glucose metabolism and systemic metabolic disorders. Furthermore, the anti-inflammation and energy metabolism effects of short chain FAs have been linked to the activation of GPR41 and GPR43. In this review, we summarize recent progress in research on FFAs and their physiological roles in the regulation of energy metabolism. PMID:27023530

  3. Nutritional Signaling via Free Fatty Acid Receptors

    PubMed Central

    Miyamoto, Junki; Hasegawa, Sae; Kasubuchi, Mayu; Ichimura, Atsuhiko; Nakajima, Akira; Kimura, Ikuo

    2016-01-01

    Excess energy is stored primarily as triglycerides, which are mobilized when demand for energy arises. Dysfunction of energy balance by excess food intake leads to metabolic diseases, such as obesity and diabetes. Free fatty acids (FFAs) provided by dietary fat are not only important nutrients, but also contribute key physiological functions via FFA receptor (FFAR)-mediated signaling molecules, which depend on FFAs’ carbon chain length and the ligand specificity of the receptors. Functional analyses have revealed that FFARs are critical for metabolic functions, such as peptide hormone secretion and inflammation, and contribute to energy homeostasis. In particular, recent studies have shown that the administration of selective agonists of G protein-coupled receptor (GPR) 40 and GPR120 improved glucose metabolism and systemic metabolic disorders. Furthermore, the anti-inflammation and energy metabolism effects of short chain FAs have been linked to the activation of GPR41 and GPR43. In this review, we summarize recent progress in research on FFAs and their physiological roles in the regulation of energy metabolism. PMID:27023530

  4. High flux compact neutron generators

    SciTech Connect

    Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

    2001-06-15

    Compact high flux neutron generators are developed at the Lawrence Berkeley National Laboratory. The neutron production is based on D-D or D-T reaction. The deuterium or tritium ions are produced from plasma using either a 2 MHz or 13.56 MHz radio frequency (RF) discharge. RF-discharge yields high fraction of atomic species in the beam which enables higher neutron output. In the first tube design, the ion beam is formed using a multiple hole accelerator column. The beam is accelerated to energy of 80 keV by means of a three-electrode extraction system. The ion beam then impinges on a titanium target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated. The MCNP computation code has predicted a neutron flux of {approximately}10{sup 11} n/s for the D-D reaction at beam intensity of 1.5 A at 150 kV. The neutron flux measurements of this tube design will be presented. Recently new compact high flux tubes are being developed which can be used for various applications. These tubes also utilize RF-discharge for plasma generation. The design of these tubes and the first measurements will be discussed in this presentation.

  5. Superconducting flux flow digital circuits

    DOEpatents

    Hietala, V.M.; Martens, J.S.; Zipperian, T.E.

    1995-02-14

    A NOR/inverter logic gate circuit and a flip flop circuit implemented with superconducting flux flow transistors (SFFTs) are disclosed. Both circuits comprise two SFFTs with feedback lines. They have extremely low power dissipation, very high switching speeds, and the ability to interface between Josephson junction superconductor circuits and conventional microelectronics. 8 figs.

  6. Superconducting flux flow digital circuits

    DOEpatents

    Hietala, Vincent M.; Martens, Jon S.; Zipperian, Thomas E.

    1995-01-01

    A NOR/inverter logic gate circuit and a flip flop circuit implemented with superconducting flux flow transistors (SFFTs). Both circuits comprise two SFFTs with feedback lines. They have extremely low power dissipation, very high switching speeds, and the ability to interface between Josephson junction superconductor circuits and conventional microelectronics.

  7. Flux Compression in HTS Films

    NASA Astrophysics Data System (ADS)

    Mikheenko, P.; Colclough, M. S.; Chakalov, R.; Kawano, K.; Muirhead, C. M.

    We report on experimental investigation of the effect of flux compression in superconducting YBa2Cu3Ox (YBCO) films and YBCO/CMR (Colossal Magnetoresistive) multilayers. The flux compression produces positive magnetic moment (m) upon the cooling in a field from above to below the critical temperature. We found effect of compression in all measured films and multilayers. In accordance with theoretical calculations, m is proportional to applied magnetic field. The amplitude of the effect depends on the cooling rate, which suggests the inhomogeneous cooling as its origin. The positive moment is always very small, a fraction of a percent of the ideal diamagnetic response. A CMR layer in contact with HTS decreases the amplitude of the effect. The flux compression weakly depends on sample size, but sensitive to its form and topology. The positive magnetic moment does not appear in bulk samples at low rates of the cooling. Our results show that the main features of the flux compression are very different from those in Paramagnetic Meissner effect observed in bulk high temperature superconductors and Nb disks.

  8. Effects of intravenous methyl palmoxirate on the turnover and oxidation of fatty acids in conscious dogs

    SciTech Connect

    Bailey, J.W.; Jensen, M.D.; Miles, J.M. )

    1991-04-01

    Methyl palmoxirate (MP) is a member of a class of hypoglycemic agents that inhibit fatty acid oxidation in vitro. The studies presented here were undertaken to determine the effects of intravenous (IV) MP on tracer-determined rates of fatty acid oxidation and systemic adipose tissue lipolysis in dogs. MP (40 mg/kg) was administered IV to five mongrel dogs using a primed continuous infusion of (1-{sup 14}C)palmitate to determine palmitate kinetics. Palmitate concentration and rate of appearance decreased rapidly (from 155 +/- 25 to 47 +/- 6 mumol/L and 2.9 +/- 0.5 to 0.9 +/- 0.2 mumol.kg-1.min-1, respectively, at 15 minutes, both P less than .05). Palmitate oxidation also decreased, from 1.5 +/- 0.4 to 0.3 +/- 0.1 mumol.kg-1.min-1, P less than .05. Oxidative clearance decreased by approximately 50% 90 minutes after MP administration (P less than .05). Fractional oxidation of palmitate also decreased by approximately 40% (P less than .05). Plasma insulin increased from 45 +/- 6 to 240 +/- 93 pmol/L at 15 minutes (P less than .05). Plasma glucose decreased over the course of study by approximately 20% (P less than .05). In summary, MP has a specific inhibitory effect on plasma free fatty acid (FFA) oxidation in dogs, confirming previous in vitro observations in an in vivo model. In addition, it has a potent antilipolytic effect when administered IV, an effect likely mediated by stimulation of insulin secretion. The observation that systemic FFA oxidation was only partially suppressed at this relatively high dose of MP is consistent with previous studies suggesting that MP may exert its major effect in the liver, and may be less potent in extrahepatic tissues.

  9. Fluxes across a thermohaline interface

    NASA Astrophysics Data System (ADS)

    Fleury, M.; Lueck, R. G.

    1991-07-01

    Measurements of velocity and temperature microstructure and hydrography were made with a towed vehicle moving in and around a single interface in a double-diffusive staircase. The interface was traversed 222 times in a saw-tooth pattern over a track 35 km long. The salinity and potential temperature and density in the mixed layers adjacent to the interface were spatially uniform except for one 8 km long anomaly. The rate of dissipation of kinetic energy was uniformly low in the interface and in the mixed layers, except for one section 600 m long where a Kelvin-Helmholtz instability generated turbulence. For the non-turbulent section of the interface, the mean rate of dissipation was 30.2 × 10 -10 W kg -1 in the mixed layers and 9.5 × 10 -10 W kg -1 in the interface. The non-dimensional dissipation rate, ɛ/vN 2, was almost always less than 16 in the interface and therfore, there was no turblent buoyancy flux according to ROHRet al. (1988, Journal of Fluid Mechanics, 195, 77-111). The average double-diffusive flux of buoyancy by heat was 3.6 × 10 -10 W kg -1. Under certain assumptions the ratio of the flux of buoyancy by heat and salt can be estimated to be 0.53 ± 0.10, in good agreement with laboratory and theoretical estimates for salt fingers. The average Cox number was about 8 in the interface, consistent with the theories of STERN (1975, Ocean circulation physics, Academic Press) and KUNZE (1987, Journal of Marine Research, 45 533-556), but displayed an inverse dependence on the vertical temperature gradient which was not predicted. As a result, the flux of buoyancy, as well as the individual contributions by heat and salt, were independent of the local mean vertical temperature gradient and the buoyancy frequency. The length of the turbulent section of the interface was only 1.7% of the total length observed. However, the turbulence was intense—the mean rate of dissipation was 2.5 × 10 -8 W kg -1—and may have sufficiently enhanced the flux of heat to

  10. Preparation of solid acid catalyst from glucose-starch mixture for biodiesel production.

    PubMed

    Chen, Guo; Fang, Baishan

    2011-02-01

    The aim of this work is to study the catalyst prepared by glucose-starch mixture. Assessment experiments showed that solid acid behaved the highest esterification activity when glucose and corn powder were mixed at ratio of 1:1, carbonized at 400°C for 75 min and sulfonated with concentrated H(2)SO(4) (98%) at 150°C for 5 h. The catalyst was characterized by acid activity measurement, XPS, TEM and FT-IR. The results indicated that solid acid composed of CS(0.073)O(0.541) has both Lewis acid sites and Bronsted acid sites caused by SO(3)H and COOH. The conversions of oleic acid esterification and triolein transesterification are 96% and 60%, respectively. Catalyst for biodiesel production from waste cottonseed oil containing high free fatty acid (FFA 55.2 wt.%) afforded the methyl ester yield of about 90% after 12h. The catalyst deactivated gradually after recycles usage, but it could be regenerated by H(2)SO(4) treatment. PMID:21067915

  11. Fatty acid methyl ester profiles of bat wing surface lipids.

    PubMed

    Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-11-01

    Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration. PMID:25227993

  12. Insulin resistance reduces arterial prostacyclin synthase and eNOS activities by increasing endothelial fatty acid oxidation

    PubMed Central

    Du, Xueliang; Edelstein, Diane; Obici, Silvana; Higham, Ninon; Zou, Ming-Hui; Brownlee, Michael

    2006-01-01

    Insulin resistance markedly increases cardiovascular disease risk in people with normal glucose tolerance, even after adjustment for known risk factors such as LDL, triglycerides, HDL, and systolic blood pressure. In this report, we show that increased oxidation of FFAs in aortic endothelial cells without added insulin causes increased production of superoxide by the mitochondrial electron transport chain. FFA-induced overproduction of superoxide activated a variety of proinflammatory signals previously implicated in hyperglycemia-induced vascular damage and inactivated 2 important antiatherogenic enzymes, prostacyclin synthase and eNOS. In 2 nondiabetic rodent models — insulin-resistant, obese Zucker (fa/fa) rats and high-fat diet–induced insulin-resistant mice — inactivation of prostacyclin synthase and eNOS was prevented by inhibition of FFA release from adipose tissue; by inhibition of the rate-limiting enzyme for fatty acid oxidation in mitochondria, carnitine palmitoyltransferase I; and by reduction of superoxide levels. These studies identify what we believe to be a novel mechanism contributing to the accelerated atherogenesis and increased cardiovascular disease risk occurring in people with insulin resistance. PMID:16528409

  13. Fatty acid represses insulin receptor gene expression by impairing HMGA1 through protein kinase C{epsilon}

    SciTech Connect

    Dey, Debleena; Bhattacharya, Anirban; Roy, SibSankar; Bhattacharya, Samir . E-mail: smrbhattacharya@gmail.com

    2007-06-01

    It is known that free fatty acid (FFA) contributes to the development of insulin resistance and type2 diabetes. However, the underlying mechanism in FFA-induced insulin resistance is still unclear. In the present investigation we have demonstrated that palmitate significantly (p < 0.001) inhibited insulin-stimulated phosphorylation of PDK1, the key insulin signaling molecule. Consequently, PDK1 phosphorylation of plasma membrane bound PKC{epsilon} was also inhibited. Surprisingly, phosphorylation of cytosolic PKC{epsilon} was greatly stimulated by palmitate; this was then translocated to the nuclear region and associated with the inhibition of insulin receptor (IR) gene transcription. A PKC{epsilon} translocation inhibitor peptide, {epsilon}V1, suppressed this inhibitory effect of palmitate, suggesting requirement of phospho-PKC{epsilon} migration to implement palmitate effect. Experimental evidences indicate that phospho-PKC{epsilon} adversely affected HMGA1. Since HMGA1 regulates IR promoter activity, expression of IR gene was impaired causing reduction of IR on cell surface and that compromises with insulin sensitivity.

  14. Analysis of free fatty acids by ultraviolet laser desorption ionization mass spectrometry using insect wings as hydrophobic sample substrates.

    PubMed

    Pirkl, Alexander; Meier, Martin; Popkova, Yulia; Letzel, Matthias; Schnapp, Andreas; Schiller, Jürgen; Dreisewerd, Klaus

    2014-11-01

    Physiologically relevant free fatty acids (FFAs) were analyzed by UV-laser desorption/ionization orthogonal extracting time-of-flight mass spectrometry (LDI-oTOF-MS). Dissected wings from Drosophila melanogaster fruit flies were used as the hydrophobic, laser energy strongly absorbing sample substrates. Using untreated substrates produces predominantly molecular [M + K](+) ions of the FFAs, whereas other alkali metal adducts can be generated by treating the wings with the corresponding alkali hydroxide before spotting of analyte. Limits of detection for the positive ion mode were determined for mixtures of isolated FFAs to values in the low 10 pmol range. Specific values depend on chain length and degree of unsaturation. R(2) coefficients for the analysis of saturated FFAs were found to be generally close to 0.98 over about 3 orders of magnitude if an internal standard (15:0 FFA) was added. Semiquantitative analyses of mixtures containing unsaturated FFAs are also possible but require more effort on the calibration strategy. Notably, both saturated and (poly-)unsaturated FFAs are detected sensitively in the presence of relatively high concentrations of other physiologically abundant lipids (phospholipids and triacyclglycerols). This simplifies screening of the FFA composition in crude tissue extracts. This feature is demonstrated by the analysis of a crude liver extract and that of fingermarks. PMID:25268473

  15. A kinetic study on the Novozyme 435-catalyzed esterification of free fatty acids with octanol to produce octyl esters.

    PubMed

    Chowdhury, Avisha; Mitra, Debarati

    2015-01-01

    Octyl esters can serve as an important class of biolubricant components replacing their mineral oil counterparts. The purpose of the current work was to investigate the enzymatic esterification reaction of free fatty acids (FFA, from waste cooking oil) with octanol in a solvent-free system using a commercial lipase Novozyme 435. It was found that the esterificaton reaction followed the Ping-pong bi-bi kinetics with no inhibition by substrates or products within the studied concentration range. The maximum reaction rate was estimated to be 0.041 mol L(-1) g(-1) h(-1) . Additionally, the stability of Novozyme 435 in the current reaction system was studied by determining its activity and final conversion of FFA to esters after 12 successive utilizations. Novozyme 435 exhibited almost 100% enzyme activity up to 7 cycles of reaction and gradually decreased (by 5%) thereafter. The kinetic parameters evaluated from the study shall assist in the design of reactors for large-scale production of octyl esters from a cheap biomass source. The enzyme reusability data can further facilitate mass production by curtailing the cost of expensive enzyme consumption. PMID:26334440

  16. Heisenberg groups and noncommutative fluxes

    SciTech Connect

    Freed, Daniel S. . E-mail: dafr@math.utexas.edu; Moore, Gregory W.; Segal, Graeme

    2007-01-15

    We develop a group-theoretical approach to the formulation of generalized abelian gauge theories, such as those appearing in string theory and M-theory. We explore several applications of this approach. First, we show that there is an uncertainty relation which obstructs simultaneous measurement of electric and magnetic flux when torsion fluxes are included. Next, we show how to define the Hilbert space of a self-dual field. The Hilbert space is Z{sub 2}-graded and we show that, in general, self-dual theories (including the RR fields of string theory) have fermionic sectors. We indicate how rational conformal field theories associated to the two-dimensional Gaussian model generalize to (4k+2)-dimensional conformal field theories. When our ideas are applied to the RR fields of string theory we learn that it is impossible to measure the K-theory class of a RR field. Only the reduction modulo torsion can be measured.

  17. Heisenberg groups and noncommutative fluxes

    NASA Astrophysics Data System (ADS)

    Freed, Daniel S.; Moore, Gregory W.; Segal, Graeme

    2007-01-01

    We develop a group-theoretical approach to the formulation of generalized abelian gauge theories, such as those appearing in string theory and M-theory. We explore several applications of this approach. First, we show that there is an uncertainty relation which obstructs simultaneous measurement of electric and magnetic flux when torsion fluxes are included. Next, we show how to define the Hilbert space of a self-dual field. The Hilbert space is Z2-graded and we show that, in general, self-dual theories (including the RR fields of string theory) have fermionic sectors. We indicate how rational conformal field theories associated to the two-dimensional Gaussian model generalize to (4 k + 2)-dimensional conformal field theories. When our ideas are applied to the RR fields of string theory we learn that it is impossible to measure the K-theory class of a RR field. Only the reduction modulo torsion can be measured.

  18. SQUID With Integral Flux Concentrator

    NASA Technical Reports Server (NTRS)

    Peters, Palmer N.; Sisk, Robert C.

    1989-01-01

    In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

  19. Reaction kinetics of free fatty acids esterification in palm fatty acid distillate using coconut shell biochar sulfonated catalyst

    NASA Astrophysics Data System (ADS)

    Hidayat, Arif; Rochmadi, Wijaya, Karna; Budiman, Arief

    2015-12-01

    Recently, a new strategy of preparing novel carbon-based solid acids has been developed. In this research, the esterification reactions of Palm Fatty Acid Distillate (PFAD) with methanol, using coconut shell biochar sulfonated catalyst from biomass wastes as catalyst, were studied. In this study, the coconut shell biochar sulfonated catalysts were synthesized by sulfonating the coconut shell biochar using concentrated H2SO4. The kinetics of free fatty acid (FFA) esterification in PFAD using a coconut shell biochar sulfonated catalyst was also studied. The effects of the mass ratio of catalyst to oil (1-10%), the molar ratio of methanol to oil (6:1-12:1), and the reaction temperature (40-60°C) were studied for the conversion of PFAD to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to PFAD molar ratio of 12:1, the amount of catalyst of 10%w, and reaction temperature of 60°C. The proposed kinetic model shows a reversible second order reaction and represents all the experimental data satisfactorily, providing deeper insight into the kinetics of the reaction.

  20. Folic Acid

    MedlinePlus

    Folic acid is a B vitamin. It helps the body make healthy new cells. Everyone needs folic acid. For women who may get pregnant, it is really important. Getting enough folic acid before and during pregnancy can prevent major birth ...

  1. Folic Acid

    MedlinePlus

    Folic acid is used to treat or prevent folic acid deficiency. It is a B-complex vitamin needed by ... Folic acid comes in tablets. It usually is taken once a day. Follow the directions on your prescription label ...

  2. Aspartic acid

    MedlinePlus

    ... also called asparaginic acid. Aspartic acid helps every cell in the body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as ...

  3. Profile of Free Fatty Acids and Fractions of Phospholipids, Cholesterol Esters and Triglycerides in Serum of Obese Youth with and without Metabolic Syndrome

    PubMed Central

    Bermúdez-Cardona, Juliana; Velásquez-Rodríguez, Claudia

    2016-01-01

    The study evaluated the profile of circulating fatty acids (FA) in obese youth with and without metabolic syndrome (MetS) to determine its association with nutritional status, lifestyle and metabolic variables. A cross-sectional study was conducted in 96 young people, divided into three groups: obese with MetS (OBMS), obese (OB) and appropriate weight (AW). FA profiles were quantified by gas chromatography; waist circumference (WC), fat folds, lipid profile, high-sensitivity C-reactive protein, glucose, insulin, the homeostasis model assessment (HOMA index), food intake and physical activity (PA) were assessed. The OBMS group had significantly greater total free fatty acids (FFAs), palmitic-16:0 in triglyceride (TG), palmitoleic-16:1n-7 in TG and phospholipid (PL); in the OB group, these FAs were higher than in the AW group. Dihomo-gamma-linolenic (DHGL-20:3n-6) was higher in the OBMS than the AW in PL and FFAs. Linoleic-18:2n-6 in TG and PL had the lowest proportion in the OBMS group. WC, PA, total FFA, linoleic-18:2n-6 in TG and DHGL-20:3n-6 in FFAs explained 62% of the HOMA value. The OB group presented some higher proportions of FA and biochemical values than the AW group. The OBMS had proportions of some FA in the TG, PL and FFA fractions that correlated with disturbances of MetS. PMID:26891317

  4. Sediment flux and the Anthropocene.

    PubMed

    Syvitski, James P M; Kettner, Albert

    2011-03-13

    Data and computer simulations are reviewed to help better define the timing and magnitude of human influence on sediment flux--the Anthropocene epoch. Impacts on the Earth surface processes are not spatially or temporally homogeneous. Human influences on this sediment flux have a secondary effect on floodplain and delta-plain functions and sediment dispersal into the coastal ocean. Human impact on sediment production began 3000 years ago but accelerated more widely 1000 years ago. By the sixteenth century, societies were already engineering their environment. Early twentieth century mechanization has led to global signals of increased sediment flux in most large rivers. By the 1950s, this sediment disturbance signal reversed for many rivers owing to the proliferation of dams, and sediment load reduction below pristine conditions is the dominant signal today. A delta subsidence signal began in the 1930s and is now a dominant signal in terms of sea level for many coastal environments, overwhelming even the global warming imprint on sea level. Humans have engineered how most water and sediment are discharged into the coastal ocean. Hyperpycnal flow events have become more common for some rivers, and less common for other rivers. Bottom trawling is now widespread, suggesting that even continental shelves have received a significant but as yet quantified Anthropocene impact. The Anthropocene attains the level of a geological climate event, such as that seen in the transition between the Pleistocene and the Holocene. PMID:21282156

  5. Distinct Effects of Sorbic Acid and Acetic Acid on the Electrophysiology and Metabolism of Bacillus subtilis

    PubMed Central

    van Beilen, J. W. A.; Teixeira de Mattos, M. J.; Hellingwerf, K. J.

    2014-01-01

    Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness. PMID:25038097

  6. Center vortices as composites of monopole fluxes

    NASA Astrophysics Data System (ADS)

    Deldar, S.; Nejad, S. M. Hosseini

    2016-01-01

    We study the relation between the flux of a center vortex obtained from the center vortex model and the flux formed between monopoles from the Abelian gauge fixing method. Motivated by the Monte Carlo simulations which have shown that almost all monopoles are sitting on the top of vortices, we construct the fluxes of center vortices for SU (2) and SU (3) gauge groups using fractional fluxes of monopoles. Then, we compute the potentials in the fundamental representation induced by center vortices and fractional fluxes of monopoles. We show that by combining the fractional fluxes of monopoles one can produce the center vortex fluxes for SU (3) gauge group in a "center vortex model". Comparing the potentials, we conclude that the fractional fluxes of monopoles attract each other.

  7. Energetic particle characteristics of magnetotail flux ropes

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Klecker, B.; Hovestadt, D.; Gloeckler, G.; Ipavich, F. M.; Galvin, A. B.

    1985-01-01

    During the recent ISEE-3 Geotail Mission three events have been identified from the magnetometer data which are consistent with a spacecraft crossing of a magnetotail flux rope. Energetic electron and proton observations obtained by the Max-Planck-Institut/University of Maryland sensor system during two of the possible flux rope events are presented. During one event remote sensing of the flux rope with energetic protons reveals that the flux rope is crossed by the spacecraft from south to north. This allows determination of the bandedness of the magnetic field twist and of the flux rope velocity relative to the spacecraft. A minimal flux rope radius of 3 earth radii is derived. Energetic proton intensity is highest just inside of the flux rope and decreases towards the core. Energetic electrons are streaming tailward near the outer boundary, indicating openness of the field lines, and are isotropic through the inner part of the flux rope.

  8. High-flux solar photon processes

    SciTech Connect

    Lorents, D C; Narang, S; Huestis, D C; Mooney, J L; Mill, T; Song, H K; Ventura, S

    1992-06-01

    This study was commissioned by the National Renewable Energy Laboratory (NREL) for the purpose of identifying high-flux photoprocesses that would lead to beneficial national and commercial applications. The specific focus on high-flux photoprocesses is based on the recent development by NREL of solar concentrator technology capable of delivering record flux levels. We examined photolytic and photocatalytic chemical processes as well as photothermal processes in the search for processes where concentrated solar flux would offer a unique advantage. 37 refs.

  9. Force sensor using changes in magnetic flux

    NASA Technical Reports Server (NTRS)

    Pickens, Herman L. (Inventor); Richard, James A. (Inventor)

    2012-01-01

    A force sensor includes a magnetostrictive material and a magnetic field generator positioned in proximity thereto. A magnetic field is induced in and surrounding the magnetostrictive material such that lines of magnetic flux pass through the magnetostrictive material. A sensor positioned in the vicinity of the magnetostrictive material measures changes in one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux.

  10. [Metabolic flux analysis of L-serine synthesis by Corynebacterium glutamicum SYPS-062].

    PubMed

    Zhang, Xiaomei; Dou, Wenfang; Xu, Hongyu; Xu, Zhenghong

    2010-10-01

    Corynebacterium glutamicum SYPS-062 was an L-serine producing strain stored at our lab and could produce L-serine directly from sugar. We studied the effects of cofactors in one carbon unit metabolism-folate and VB12 on the cell growth, sucrose consumption and L-serine production by SYPS-062. In the same time, the metabolic flux distribution was determined in different conditions. The supplementation of folate or VB12 enhanced the cell growth, energy synthesis, and finally increased the flux of pentose phosphate pathway (HMP), whereas the carbon flux to L-serine was decreased. The addition of VB12 not only increased the ratio of L-serine synthesis pathway on G3P joint, but also caused the insufficiency of tricarboxylic acid cycle (TCA) flux, which needed more anaplerotic reaction flux to replenish TCA cycle, that was an important limiting factor for the further increasing of the L-serine productivity. PMID:21218623

  11. Nitrogen oxide fluxes over a ponderosa pine plantation during BEARPEX-2009

    NASA Astrophysics Data System (ADS)

    Min, K.; Lafranchi, B. W.; Pusede, S. E.; Browne, E. C.; Wooldridge, P. J.; Cohen, R. C.

    2009-12-01

    The biosphere-atmosphere exchange of reactive nitrogen oxides affects atmospheric oxidative capacity and ecosystem nutrient cycling. During the Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX-2009), eddy covariance fluxes of NO2, sum of peroxy nitrates (∑PNs), sum of alkyl nitrates (∑ANs), and nitric acid (HNO3) were monitored from July 4 to July 26 above a ponderosa pine plantation in the Sierra Nevada Mountains of California using thermal dissociation - laser induced fluorescence (TD-LIF). NO2 fluxes are found to be positive and ∑AN fluxes negative supporting previous research (Farmer and Cohen, 2006). In contrast, we report downward ∑PN and HNO3 fluxes. We present these results and interpret the relationship between our flux observations and concurrent NO2, ∑PN, ∑AN, and HNO3 gradient measurements.

  12. Latent Heat in Soil Heat Flux Measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface energy balance includes a term for soil heat flux. Soil heat flux is difficult to measure because it includes conduction and convection heat transfer processes. Accurate representation of soil heat flux is an important consideration in many modeling and measurement applications. Yet, the...

  13. Apparatus for measuring a flux of neutrons

    DOEpatents

    Stringer, James L.

    1977-01-01

    A flux of neutrons is measured by disposing a detector in the flux and applying electronic correlation techniques to discriminate between the electrical signals generated by the neutron detector and the unwanted interfering electrical signals generated by the incidence of a neutron flux upon the cables connecting the detector to the electronic measuring equipment at a remote location.

  14. Flux-limited diffusion with relativistic corrections

    SciTech Connect

    Pomraning, G.C.

    1983-03-15

    A recently reported flux-limited diffusion theory is extended to include relativistic terms, correct to first order in the fluid velocity. We show that this diffusion theory is fully flux limited, and yields the correct result for the radiative flux in the classical diffusion limit, namely a Fick's law component plus a v/c convective term.

  15. Advanced high temperature heat flux sensors

    NASA Technical Reports Server (NTRS)

    Atkinson, W.; Hobart, H. F.; Strange, R. R.

    1983-01-01

    To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development.

  16. 13C metabolic flux analysis at a genome-scale.

    PubMed

    Gopalakrishnan, Saratram; Maranas, Costas D

    2015-11-01

    Metabolic models used in 13C metabolic flux analysis generally include a limited number of reactions primarily from central metabolism. They typically omit degradation pathways, complete cofactor balances, and atom transition contributions for reactions outside central metabolism. This study addresses the impact on prediction fidelity of scaling-up mapping models to a genome-scale. The core mapping model employed in this study accounts for (75 reactions and 65 metabolites) primarily from central metabolism. The genome-scale metabolic mapping model (GSMM) (697 reaction and 595 metabolites) is constructed using as a basis the iAF1260 model upon eliminating reactions guaranteed not to carry flux based on growth and fermentation data for a minimal glucose growth medium. Labeling data for 17 amino acid fragments obtained from cells fed with glucose labeled at the second carbon was used to obtain fluxes and ranges. Metabolic fluxes and confidence intervals are estimated, for both core and genome-scale mapping models, by minimizing the sum of square of differences between predicted and experimentally measured labeling patterns using the EMU decomposition algorithm. Overall, we find that both topology and estimated values of the metabolic fluxes remain largely consistent between core and GSM model. Stepping up to a genome-scale mapping model leads to wider flux inference ranges for 20 key reactions present in the core model. The glycolysis flux range doubles due to the possibility of active gluconeogenesis, the TCA flux range expanded by 80% due to the availability of a bypass through arginine consistent with labeling data, and the transhydrogenase reaction flux was essentially unresolved due to the presence of as many as five routes for the inter-conversion of NADPH to NADH afforded by the genome-scale model. By globally accounting for ATP demands in the GSMM model the unused ATP decreased drastically with the lower bound matching the maintenance ATP requirement. A non

  17. Perfluorooctanoic acid exposure alters polyunsaturated fatty acid composition, induces oxidative stress and activates the AKT/AMPK pathway in mouse epididymis.

    PubMed

    Lu, Yin; Pan, Yitao; Sheng, Nan; Zhao, Allan Z; Dai, Jiayin

    2016-09-01

    Perfluorooctanoic acid (PFOA) is a degradation-resistant compound with a carbon-fluorine bond. Although PFOA emissions have been reduced since 2000, it remains persistent in the environment. Several studies on laboratory animals indicate that PFOA exposure can impact male fertility. Here, adult male mice received either PFOA (1.25, 5 or 20 mg/kg/d) or an equal volume of water for 28 d consecutively. PFOA accumulated in the epididymis in a dose-dependent manner and resulted in reduced epididymis weight, lower levels of triglycerides (TG), cholesterol (CHO), and free fatty acids (FFA), and activated AKT/AMPK signaling in the epididymis. Altered polyunsaturated fatty acid (PUFA) compositions, such as a higher arachidonic acid:linoleic acid (AA:LA) ratio, concomitant with excessive oxidative stress, as demonstrated by increased malonaldehyde (MDA) and decreased glutathione peroxidase (GSH-Px) in the epididymis, were observed in epididymis tissue following treatment with PFOA. These results indicate that the epididymis is a potential target of PFOA. Oxidative stress and PUFA alteration might help explain the sperm injury and male reproductive dysfunction induced by PFOA exposure. PMID:27262104

  18. Vanillic acid prevents the deregulation of lipid metabolism, endothelin 1 and up regulation of endothelial nitric oxide synthase in nitric oxide deficient hypertensive rats.

    PubMed

    Kumar, Subramanian; Prahalathan, Pichavaram; Saravanakumar, Murugesan; Raja, Boobalan

    2014-11-15

    Hypertension is one of the main factors causing cardiovascular diseases. The present study was designed to evaluate the protective effect of vanillic acid against nitric oxide deficient rats. Hypertension was induced in adult male albino rats of Wistar strain, weighing 180-220g, by oral administration of N(ω)-nitro-l arginine methyl ester (l-NAME) 40mg/kg in drinking water for 4 weeks. Vanillic acid was administered orally at a dose of 50mg/kg b.w. Nitric oxide deficient rats showed increased levels of mean arterial pressure (MAP), heart rate (HR) and decreased heart nitric oxide metabolites (NOx). A significant increase in the levels of plasma cholesterol, low density lipoprotein-cholesterol (LDL-C), very low density lipoprotein-cholesterol (VLDL-C), triglycerides (TG), free fatty acids (FFA), phospholipids (PL), 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase in the plasma, liver and kidney and decreased level of high density lipoprotein-cholesterol (HDL-C) are observed, whereas there is a decrease in the activities of plasma lipoprotein lipase (LPL) and lecithin cholesterol acyl transferase (LCAT) in nitric oxide deficient rats. l-NAME rats also showed an increase in TC, TG, FFA and PL levels in the liver and kidney tissues. Vanillic acid treatment brought the above parameters towards near normal level. Moreover the down regulated endothelial nitric oxide synthase (eNOS) and up regulated expression of endothelin 1 (ET1) components was also attenuated by vanillic acid treatment. All the above outcomes were confirmed by the histopathological examination. These results suggest that vanillic acid has enough potential to attenuate hypertension, dyslipidemia and hepatic and renal damage in nitric oxide deficient rats. PMID:25239071

  19. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    PubMed Central

    Schwender, Jörg; König, Christina; Klapperstück, Matthias; Heinzel, Nicolas; Munz, Eberhard; Hebbelmann, Inga; Hay, Jordan O.; Denolf, Peter; De Bodt, Stefanie; Redestig, Henning; Caestecker, Evelyne; Jakob, Peter M.; Borisjuk, Ljudmilla; Rolletschek, Hardy

    2014-01-01

    An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis (MFA) was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident flux information was eventually used for comparative analysis of flux vs. transcript (metabolite). Metabolite profiling succeeded in identifying 79 intermediates within the central metabolism, some of which differed quantitatively between the two accessions and displayed a significant shift corresponding to flux. An RNA-Seq based transcriptome analysis revealed a large number of genes which were differentially transcribed in the two accessions, including some enzymes/proteins active in major metabolic pathways. With a few exceptions, differential activity in the major pathways (glycolysis, TCA cycle, amino acid, and fatty acid synthesis) was not reflected in contrasting abundances of the relevant transcripts. The conclusion was that transcript abundance on its own cannot be used to infer metabolic activity/fluxes in central plant metabolism. This limitation needs to be borne in mind in evaluating transcriptome data and designing metabolic engineering experiments. PMID:25506350

  20. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    DOE PAGESBeta

    Schwender, Jorg; Konig, Christina; Klapperstuck, Matthias; Heinzel, Nicolas; Munz, Eberhard; Hebbelmann, Inga; Hay, Jordan O.; Denolf, Peter; De Bodt, Stefanie; Redestig, Henning; et al

    2014-11-28

    An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis (MFA) was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident flux information was eventually used for comparative analysis of flux vs. transcript (metabolite). Metabolite profiling succeeded in identifying 79 intermediates within the central metabolism,more » some of which differed quantitatively between the two accessions and displayed a significant shift corresponding to flux. An RNA-Seq based transcriptome analysis revealed a large number of genes which were differentially transcribed in the two accessions, including some enzymes/proteins active in major metabolic pathways. With a few exceptions, differential activity in the major pathways (glycolysis, TCA cycle, amino acid, and fatty acid synthesis) was not reflected in contrasting abundances of the relevant transcripts. The conclusion was that transcript abundance on its own cannot be used to infer metabolic activity/fluxes in central plant metabolism. Lastly, this limitation needs to be borne in mind in evaluating transcriptome data and designing metabolic engineering experiments.« less

  1. Transcript abundance on its own cannot be used to infer fluxes in central metabolism

    SciTech Connect

    Schwender, Jorg; Konig, Christina; Klapperstuck, Matthias; Heinzel, Nicolas; Munz, Eberhard; Hebbelmann, Inga; Hay, Jordan O.; Denolf, Peter; De Bodt, Stefanie; Redestig, Henning; Caestecker, Evelyne; Jakob, Peter M.; Borisjuk, Ljudmilla; Rolletschek, Hardy

    2014-11-28

    An attempt has been made to define the extent to which metabolic flux in central plant metabolism is reflected by changes in the transcriptome and metabolome, based on an analysis of in vitro cultured immature embryos of two oilseed rape (Brassica napus) accessions which contrast for seed lipid accumulation. Metabolic flux analysis (MFA) was used to constrain a flux balance metabolic model which included 671 biochemical and transport reactions within the central metabolism. This highly confident flux information was eventually used for comparative analysis of flux vs. transcript (metabolite). Metabolite profiling succeeded in identifying 79 intermediates within the central metabolism, some of which differed quantitatively between the two accessions and displayed a significant shift corresponding to flux. An RNA-Seq based transcriptome analysis revealed a large number of genes which were differentially transcribed in the two accessions, including some enzymes/proteins active in major metabolic pathways. With a few exceptions, differential activity in the major pathways (glycolysis, TCA cycle, amino acid, and fatty acid synthesis) was not reflected in contrasting abundances of the relevant transcripts. The conclusion was that transcript abundance on its own cannot be used to infer metabolic activity/fluxes in central plant metabolism. Lastly, this limitation needs to be borne in mind in evaluating transcriptome data and designing metabolic engineering experiments.

  2. Altering fatty acid availability does not impair prolonged, continuous running to fatigue: evidence for carbohydrate dependence.

    PubMed

    Leckey, Jill J; Burke, Louise M; Morton, James P; Hawley, John A

    2016-01-15

    We determined the effect of suppressing lipolysis via administration of nicotinic acid (NA) on fuel substrate selection and half-marathon running capacity. In a single-blinded, Latin square design, 12 competitive runners completed four trials involving treadmill running until volitional fatigue at a pace based on 95% of personal best half-marathon time. Trials were completed in a fed or overnight fasted state: 1) carbohydrate (CHO) ingestion before (2 g CHO·kg(-1)·body mass(-1)) and during (44 g/h) [CFED]; 2) CFED plus NA ingestion [CFED-NA]; 3) fasted with placebo ingestion during [FAST]; and 4) FAST plus NA ingestion [FAST-NA]. There was no difference in running distance (CFED, 21.53 ± 1.07; CFED-NA, 21.29 ± 1.69; FAST, 20.60 ± 2.09; FAST-NA, 20.11 ± 1.71 km) or time to fatigue between the four trials. Concentrations of plasma free fatty acids (FFA) and glycerol were suppressed following NA ingestion irrespective of preexercise nutritional intake but were higher throughout exercise in FAST compared with all other trials (P < 0.05). Rates of whole-body CHO oxidation were unaffected by NA ingestion in the CFED and FAST trials, but were lower in the FAST trial compared with the CFED-NA trial (P < 0.05). CHO was the primary substrate for exercise in all conditions, contributing 83-91% to total energy expenditure with only a small contribution from fat-based fuels. Blunting the exercise-induced increase in FFA via NA ingestion did not impair intense running capacity lasting ∼85 min, nor did it alter patterns of substrate oxidation in competitive athletes. Although there was a small but obligatory use of fat-based fuels, the oxidation of CHO-based fuels predominates during half-marathon running. PMID:26586912

  3. Acid Rain.

    ERIC Educational Resources Information Center

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  4. Flux distributions in jointed ? tapes

    NASA Astrophysics Data System (ADS)

    Koblischka, M. R.; Johansen, T. H.; Bratsberg, H.; Vase, P.

    1998-06-01

    Superconducting joints between monofilamentary, Ag-sheathed 0953-2048/11/6/005/img8 tapes were investigated by means of magneto-optic imaging. Two types of joint were studied; one joint with direct contact between the tape cores, and the other one with an Ag layer between them. The local flux distributions directly reveal the obstacles hindering the current flow through the joints. The direct contact of the tape cores provides joints which can carry about 80% of the current of the original tape, whereas the joints with the Ag layer are considerably worse. This difference becomes even more drastic in applied magnetic fields.

  5. Methane Fluxes from Subtropical Wetlands

    NASA Astrophysics Data System (ADS)

    DeLucia, N.; Gomez-Casanovas, N.; Bernacchi, C.

    2013-12-01

    It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on climate conditions. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are one of the main sources for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04'N, 81o21'8.56'W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified that CH4 emissions from subtropical wetlands were larger when high soil moisture was coupled with high temperatures. The presence of cattle only amplified these results. These results help quantify

  6. Geometrical correction factors for heat flux meters

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Papell, S. S.

    1974-01-01

    General formulas are derived for determining gage averaging errors of strip-type heat flux meters used in the measurement of one-dimensional heat flux distributions. The local averaging error e(x) is defined as the difference between the measured value of the heat flux and the local value which occurs at the center of the gage. In terms of e(x), a correction procedure is presented which allows a better estimate for the true value of the local heat flux. For many practical problems, it is possible to use relatively large gages to obtain acceptable heat flux measurements.

  7. ACCURACY OF SOIL HEAT FLUX MEASUREMENTS MADE WITH FLUX PLATES OF CONTRASTING PROPERTIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flux plate measurements of soil heat flux (G) may include significant errors unless the plates are carefully installed and known errors accounted for. The objective of this research was to quantify potential errors in G when using soil heat flux plates of contrasting designs. Five flux plates with...

  8. Acidification and Acid Rain

    NASA Astrophysics Data System (ADS)

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  9. Phototransduction Influences Metabolic Flux and Nucleotide Metabolism in Mouse Retina.

    PubMed

    Du, Jianhai; Rountree, Austin; Cleghorn, Whitney M; Contreras, Laura; Lindsay, Ken J; Sadilek, Martin; Gu, Haiwei; Djukovic, Danijel; Raftery, Dan; Satrústegui, Jorgina; Kanow, Mark; Chan, Lawrence; Tsang, Stephen H; Sweet, Ian R; Hurley, James B

    2016-02-26

    Production of energy in a cell must keep pace with demand. Photoreceptors use ATP to maintain ion gradients in darkness, whereas in light they use it to support phototransduction. Matching production with consumption can be accomplished by coupling production directly to consumption. Alternatively, production can be set by a signal that anticipates demand. In this report we investigate the hypothesis that signaling through phototransduction controls production of energy in mouse retinas. We found that respiration in mouse retinas is not coupled tightly to ATP consumption. By analyzing metabolic flux in mouse retinas, we also found that phototransduction slows metabolic flux through glycolysis and through intermediates of the citric acid cycle. We also evaluated the relative contributions of regulation of the activities of α-ketoglutarate dehydrogenase and the aspartate-glutamate carrier 1. In addition, a comprehensive analysis of the retinal metabolome showed that phototransduction also influences steady-state concentrations of 5'-GMP, ribose-5-phosphate, ketone bodies, and purines. PMID:26677218

  10. Flux Sampling Errors for Aircraft and Towers

    NASA Technical Reports Server (NTRS)

    Mahrt, Larry

    1998-01-01

    Various errors and influences leading to differences between tower- and aircraft-measured fluxes are surveyed. This survey is motivated by reports in the literature that aircraft fluxes are sometimes smaller than tower-measured fluxes. Both tower and aircraft flux errors are larger with surface heterogeneity due to several independent effects. Surface heterogeneity may cause tower flux errors to increase with decreasing wind speed. Techniques to assess flux sampling error are reviewed. Such error estimates suffer various degrees of inapplicability in real geophysical time series due to nonstationarity of tower time series (or inhomogeneity of aircraft data). A new measure for nonstationarity is developed that eliminates assumptions on the form of the nonstationarity inherent in previous methods. When this nonstationarity measure becomes large, the surface energy imbalance increases sharply. Finally, strategies for obtaining adequate flux sampling using repeated aircraft passes and grid patterns are outlined.

  11. Automated Heat-Flux-Calibration Facility

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1989-01-01

    Computer control speeds operation of equipment and processing of measurements. New heat-flux-calibration facility developed at Lewis Research Center. Used for fast-transient heat-transfer testing, durability testing, and calibration of heat-flux gauges. Calibrations performed at constant or transient heat fluxes ranging from 1 to 6 MW/m2 and at temperatures ranging from 80 K to melting temperatures of most materials. Facility developed because there is need to build and calibrate very-small heat-flux gauges for Space Shuttle main engine (SSME).Includes lamp head attached to side of service module, an argon-gas-recirculation module, reflector, heat exchanger, and high-speed positioning system. This type of automated heat-flux calibration facility installed in industrial plants for onsite calibration of heat-flux gauges measuring fluxes of heat in advanced gas-turbine and rocket engines.

  12. Energetic consequences of flux emergence

    NASA Astrophysics Data System (ADS)

    Tarr, Lucas Adrian

    When magnetic field in the solar convection zone buoyantly rises to pierce the visible solar surface (photosphere), the atmosphere (corona) above this surface must respond in some way. One response of the coronal field to photospheric forcing is the creation of stress in the magnetic field, generating large currents and storing magnetic free energy. Using a topological model of the coronal magnetic field we will quantify this free energy. We find the free energy just prior to major flares in active regions to be between 30% and 50% of the potential field energy. In a second way, the coronal field may topologically restructure to form new magnetic connections with newly emerged fields. We use our topological model to quantify the rapid restructuring in the case of solar flare and coronal mass ejections, finding that between 1% and 10% of total active region flux is exchanged. Finally, we use observational data to quantify the slow, quiescent reconnection with preexisting field, and find that for small active regions between 20% and 40% of the total emerged flux may have reconnected at any given time.

  13. Atmospheric discharges and particle fluxes

    NASA Astrophysics Data System (ADS)

    Chilingarian, A.; Chilingaryan, S.; Reymers, A.

    2015-07-01

    Fluxes of the electrons, gamma rays, and neutrons observed by particle detectors located on the Earth's surface during thunderstorms originate so-called Thunderstorm Ground Enhancements (TGEs). The relativistic runaway electron avalanches giving rise to TGEs originate in the thundercloud's lower dipole between the main negatively charged region in the middle of the thundercloud and transient lower positively charged region. Acceleration of electrons in the upper dipole between main negative and main positive charge regions leads to initiation of the terrestrial gamma flashes (TGFs) intensive researched during the last two decades by orbiting gamma ray observatories. TGFs are exceptionally intense, submillisecond bursts of electromagnetic radiation directed to the open space from the thunderstorm atmosphere. Unlike visible lightning, TGF beams do not create a hot plasma channel and optical flash; hence, in the literature they got name "dark lightning." We investigate the TGEs development in 1 min and 1 s time series of particle detector count rates. Synchronized time series of the near-surface electric field and lightning occurrences allows interconnecting two atmospheric phenomena. Registration of the Extensive Air Showers allows approaching problems of relation of the lightning occurrences and particle fluxes.

  14. Constrained Allocation Flux Balance Analysis.

    PubMed

    Mori, Matteo; Hwa, Terence; Martin, Olivier C; De Martino, Andrea; Marinari, Enzo

    2016-06-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferred at fast growth). In addition, CAFBA allows for quantitatively accurate predictions on the rate of acetate excretion and growth yield based on only 3 parameters determined by empirical growth laws. PMID:27355325

  15. Flux of Millimetric Space Debris

    NASA Technical Reports Server (NTRS)

    Goldstein, R. M.; Goldstein, S. J., Jr.

    1995-01-01

    In 21.4 hr of zenith radar observations on 4 days at 8510 MHz, we found 831 particles with altitudes between 177 and 1662 km. From the duration of the echoes and the angular size (0.030 deg) of the antenna beam 157 particles were identified as passing through the side lobes and not through the main beam. Our analysis is based on the 674 particles that did not broaden the beam. On the assumptions that these particles went through the main beam, their radar cross sections vary between 0.02 and 260 sq mm , and their radial velocities vary between +/- 700 m/s. If they are conducting spheres, their diameters lie between 2 and 18 mm. If not, they must be larger. The flux of these particles, that is the number per sq km day, was determined in 100 km intervals. The maximum flux, 3.3 particles per sq km day, occurs at 950 km altitude. The small and large particles are not well mixed. The largest particles occur beyond 1000 km and middle-sized particles are missing below 300 km. If the earth's atmosphere caused the smallest particles to lose energy from initial orbits identical to those of the large particles, the orbits would have lower eccentricity at low altitudes. We find a larger eccentricity for the inner particles, and conclude that two or more populations are present.

  16. Flux focusing eddy current probe

    NASA Technical Reports Server (NTRS)

    Simpson, John W. (Inventor); Clendenin, C. Gerald (Inventor); Fulton, James P. (Inventor); Wincheski, Russell A. (Inventor); Todhunter, Ronald G. (Inventor); Namkung, Min (Inventor); Nath, Shridhar C. (Inventor)

    1997-01-01

    A flux-focusing electromagnetic sensor which uses a ferromagnetic flux-focusing lens simplifies inspections and increases detectability of fatigue cracks and material loss in high conductivity material. The unique feature of the device is the ferrous shield isolating a high-turn pick-up coil from an excitation coil. The use of the magnetic shield is shown to produce a null voltage output across the receiving coil in the presence of an unflawed sample. A redistribution of the current flow in the sample caused by the presence of flaws, however, eliminates the shielding condition and a large output voltage is produced, yielding a clear unambiguous flaw signal. The maximum sensor output is obtained when positioned symmetrically above the crack. Hence, by obtaining the position of the maximum sensor output, it is possible to track the fault and locate the area surrounding its tip. The accuracy of tip location is enhanced by two unique features of the sensor; a very high signal-to-noise ratio of the probe's output which results in an extremely smooth signal peak across the fault, and a rapidly decaying sensor output outside a small area surrounding the crack tip which enables the region for searching to be clearly defined. Under low frequency operation, material thinning due to corrosion damage causes an incomplete shielding of the pick-up coil. The low frequency output voltage of the probe is therefore a direct indicator of the thickness of the test sample.

  17. Constrained Allocation Flux Balance Analysis

    PubMed Central

    Mori, Matteo; Hwa, Terence; Martin, Olivier C.

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an “ensemble averaging” procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferred at fast growth). In addition, CAFBA allows for quantitatively accurate predictions on the rate of acetate excretion and growth yield based on only 3 parameters determined by empirical growth laws. PMID:27355325

  18. A selection rule for the directions of electronic fluxes during unimolecular pericyclic reactions in the electronic ground state

    NASA Astrophysics Data System (ADS)

    Manz, Jörn; Yamamoto, Kentaro

    2012-05-01

    Unimolecular pericyclic reactions in a non-degenerate electronic ground state proceed under the constraint of zero electronic angular momentum. This restriction engenders a selection rule on the directions of electronic fluxes. Accordingly, clockwise or counter-clockwise fluxes are 'forbidden', whereas pincer-like fluxes (which consist of concerted clockwise and counter-clockwise fluxes) are 'allowed'. The selection rule is illustrated for three reactions: the degenerate Cope rearrangement of hexadiene, hydrogen transfer in malonaldehyde, and double proton transfer in the formic acid dimer.

  19. Wet Deposition Concentrations and Fluxes of Mercury in Taiwan

    NASA Astrophysics Data System (ADS)

    Sheu, G.; Lin, N.

    2010-12-01

    Taiwan is located downwind to the largest anthropogenic Hg emission source region, the East Asian continent, and thus model simulations often predicted that Taiwan could receive high Hg input via wet deposition. Therefore, a mercury (Hg) wet deposition monitoring network was established in Taiwan to collect rainwater for total Hg analysis since September 2008. The objective of this network is to establish a national database of wet deposition concentrations and fluxes of Hg. This database will later be used to develop information on spatial and temporal trends in Hg wet deposition and to evaluate the contribution of regional/long-range transport. A total of 12 sampling sites, covering urban, rural, mountain, coastal and remote island areas, were set up. Weekly samples were collected using automated wet-only precipitation collection systems. Acid-cleaned glass funnels were used for rainwater collections and samples were collected into acid-cleaned 1L Teflon bottles. Samples were retrieved and sampling trains were changed every Tuesday morning. Total Hg was quantified by dual amalgamation CVAFS after BrCl oxidation, NH2OH●HCl neutralization, and SnCl2 reduction. In 2009, total Hg concentrations of all the rainwater samples ranged from 2.1 to 82.2 ng/L. Volume-weighted mean (VWM) total Hg concentrations of all the sampling sites ranged between 7.6 and 17.2 ng/L. In general, rainwater Hg concentrations were lower in northern Taiwan sites, likely due to the dilution effect caused by higher rainfall amount. Annual wet depositional Hg fluxes ranged between 12.3 and 37.0 μg/m2 in 2009, with higher values usually observed in northern Taiwan sites. The geographical distribution of wet depositional Hg flux mimicked the distribution of accumulative rainfall amount, suggesting precipitation depth is the primary factor in determining the magnitude of wet depositional Hg flux.

  20. Determination of free fatty acids in beer wort.

    PubMed

    Bravi, Elisabetta; Benedetti, Paolo; Marconi, Ombretta; Perretti, Giuseppe

    2014-05-15

    The importance of free fatty acids (FFAs) in wort has been known for a long time because of their influence on beer quality and yeast metabolism. Lipids have a beneficial effect on yeast growth during fermentation as well as negative effects on beer quality. Lipids content of beer affects the ability to form a stable head of foam and plays an important role in beer staling. Moreover, the ratio of unsaturated and saturated fatty acids seems to be related to gushing problems. A novel, simple, and reliable procedure for quantitative analysis of FFAs in wort was developed and validated. The determination of FFAs in wort was achieved via liquid-liquid cartridge extraction, purification of FFA fraction by solid phase extraction, boron trifluoride in methanol methylation, and injection into GC-FID system. The proposed method has high accuracy (<0.3%, expressed as the bias), high precision (<1.2%, RSD), and recoveries ranging from 74% to 98%. The method was tested on two different wort samples (9° and 12° Plato). PMID:24423546

  1. Transcriptional regulation is insufficient to explain substrate-induced flux changes in Bacillus subtilis

    PubMed Central

    Chubukov, Victor; Uhr, Markus; Le Chat, Ludovic; Kleijn, Roelco J; Jules, Matthieu; Link, Hannes; Aymerich, Stephane; Stelling, Jörg; Sauer, Uwe

    2013-01-01

    One of the key ways in which microbes are thought to regulate their metabolism is by modulating the availability of enzymes through transcriptional regulation. However, the limited success of efforts to manipulate metabolic fluxes by rewiring the transcriptional network has cast doubt on the idea that transcript abundance controls metabolic fluxes. In this study, we investigate control of metabolic flux in the model bacterium Bacillus subtilis by quantifying fluxes, transcripts, and metabolites in eight metabolic states enforced by different environmental conditions. We find that most enzymes whose flux switches between on and off states, such as those involved in substrate uptake, exhibit large corresponding transcriptional changes. However, for the majority of enzymes in central metabolism, enzyme concentrations were insufficient to explain the observed fluxes—only for a number of reactions in the tricarboxylic acid cycle were enzyme changes approximately proportional to flux changes. Surprisingly, substrate changes revealed by metabolomics were also insufficient to explain observed fluxes, leaving a large role for allosteric regulation and enzyme modification in the control of metabolic fluxes. PMID:24281055

  2. (13)C-metabolic flux analysis of lipid accumulation in the oleaginous fungus Mucor circinelloides.

    PubMed

    Zhao, Lina; Zhang, Huaiyuan; Wang, Liping; Chen, Haiqin; Chen, Yong Q; Chen, Wei; Song, Yuanda

    2015-12-01

    The oleaginous fungus Mucor circinelloides is of industrial interest because it can produce high levels of polyunsaturated fatty acid γ-linolenic acid. M. circinelloides CBS 277.49 is able to accumulate less than 15% of cell dry weight as lipids, while M. circinelloides WJ11 can accumulate lipid up to 36%. In order to better understand the mechanisms behind the differential lipid accumulation in these two strains, tracer experiments with (13)C-glucose were performed with the growth of M. circinelloides and subsequent gas chromatography-mass spectrometric detection of (13)C-patterns in proteinogenic amino acids was carried out to identify the metabolic network topology and estimate intracellular fluxes. Our results showed that the high oleaginous strain WJ11 had higher flux of pentose phosphate pathway and malic enzyme, lower flux in tricarboxylic acid cycle, higher flux in glyoxylate cycle and ATP: citrate lyase, together, it might provide more NADPH and substrate acetyl-CoA for fatty acid synthesis. PMID:26318243

  3. Production of free monounsaturated fatty acids by metabolically engineered Escherichia coli

    PubMed Central

    2014-01-01

    Background Monounsaturated fatty acids (MUFAs) are the best components for biodiesel when considering the low temperature fluidity and oxidative stability. However, biodiesel derived from vegetable oils or microbial lipids always consists of significant amounts of polyunsaturated and saturated fatty acids (SFAs) alkyl esters, which hampers its practical applications. Therefore, the fatty acid composition should be modified to increase MUFA contents as well as enhancing oil and lipid production. Results The model microorganism Escherichia coli was engineered to produce free MUFAs. The fatty acyl-ACP thioesterase (AtFatA) and fatty acid desaturase (SSI2) from Arabidopsis thaliana were heterologously expressed in E. coli BL21 star(DE3) to specifically release free unsaturated fatty acids (UFAs) and convert SFAs to UFAs. In addition, the endogenous fadD gene (encoding acyl-CoA synthetase) was disrupted to block fatty acid catabolism while the native acetyl-CoA carboxylase (ACCase) was overexpressed to increase the malonyl coenzyme A (malonyl-CoA) pool and boost fatty acid biosynthesis. The finally engineered strain BL21ΔfadD/pE-AtFatAssi2&pA-acc produced 82.6 mg/L free fatty acids (FFAs) under shake-flask conditions and FFAs yield on glucose reached about 3.3% of the theoretical yield. Two types of MUFAs, palmitoleate (16:1Δ9) and cis-vaccenate (18:1Δ11) made up more than 75% of the FFA profiles. Fed-batch fermentation of this strain further enhanced FFAs production to a titer of 1.27 g/L without affecting fatty acid compositions. Conclusions This study demonstrated the possibility to regulate fatty acid composition by using metabolic engineering approaches. FFAs produced by the recombinant E. coli strain consisted of high-level MUFAs and biodiesel manufactured from these fatty acids would be more suitable for current diesel engines. PMID:24716602

  4. Isotopic Compositions of Evaporative Fluxes

    NASA Astrophysics Data System (ADS)

    Feng, X.; Lauder, A. M.; Kopec, B. G.; Dade, W. B.; Virginia, R. A.; Posmentier, E. S.

    2013-12-01

    The isotopic fluxes of evaporation from a water surface are typically computed using a one-dimensional model, originally conceptualized by Craig and Gordon (1965) and further developed and adapted to different natural settings (such as transpiration, open surface evaporation, etc.) by various investigators. These models have two distinguishing characteristics. First, there exists a laminar layer where molecular diffusion away from the water-air interface causes kinetic isotopic fractionation. The magnitude of this fractionation is controlled by the diffusion/transport coefficient of each vapor isotopologue in air and their concentration gradients, the latter being controlled by relative humidity, isotopic ratios of ambient air, and turbulent conditions (such as wind and surface roughness). Second, the horizontal variations are ignored. In particular, the effect of horizontal advection on isotopic variations in the ambient air is not considered. The research reported here addresses the effects of relinquishing the simplifying assumptions in both of these areas. We developed a model, in which the simplification of a purely laminar layer is dropped. Instead, we express the vertical transport coefficient as the sum of the molecular diffusivity, that differs for each water isotopologue, and the turbulent diffusivity that increases linearly with height but does not vary among water isotopologues. With this model, the kinetic isotopic effect reduces with height in the vicinity of the water surface, and the net isotopic fractionation through the boundary layer can be integrated. The advantage of this conceptualization is that the magnitude of kinetic isotopic fractionation can be assessed directly with changing environmental conditions, such as humidity and wind speed, rather than approximated by discontinuous empirical functions of the environmental conditions, as in the conventional models mentioned above. To address the effect of lateral heterogeneity, we expanded the

  5. Eddy fluxes in baroclinic turbulence

    NASA Astrophysics Data System (ADS)

    Thompson, Andrew F.

    The eddy heat flux generated by the statistically equilibrated baroclinic instability of a uniform, horizontal temperature gradient is studied using a two-mode quasigeostrophic model. An overview of the dependence of the eddy diffusivity of heat Dtau on the planetary potential vorticity gradient beta, the bottom friction kappa, the deformation radius lambda, the vertical shear of the large-scale flow 2U and the domain size L is provided at 70 numerical simulations with beta = 0 (f-plane) and 110 simulations with beta ≠ 0 (beta-plane). Strong, axisymmetric, well-separated baroclinic vortices dominate the equilibrated barotropic vorticity and temperature fields of f-plane turbulence. The heat flux arises from a systematic northward (southward) migration of anti-cyclonic (cyclonic) eddies with warm (cold) fluid trapped in the cores. Zonal jets form spontaneously on the beta-plane, and stationary, isotropic, jet-scale eddies align within the strong eastward-flowing regions of the jets. In both studies, the vortices and jets give rise to a strong anti-correlation between the barotropic vorticity zeta and the temperature field tau. The baroclinic mode is also an important contributor to dissipation by bottom friction and energizes the barotropic mode at scales larger than lambda. This in part explains why previous parameterizations for the eddy heat flux based on Kolmogorovian cascade theories are found to be unreliable. In a separate study, temperature and salinity profiles obtained with expendable conductivity, temperature and depth (XCTD) probes within Drake Passage, Southern Ocean are used to analyze the turbulent diapycnal eddy diffusivity kappa rho to a depth of 1000 meters. The Polar Front separates two dynamically different regions with strong, surface-intensified mixing north of the Front. South of the Polar Front mixing is weaker and peaks at a depth of approximately 500 m, near the local temperature maximum. Peak values of kapparho are found to exceed 10-3 m

  6. Role of lipase-generated free fatty acids in converting mesenteric lymph from a noncytotoxic to a cytotoxic fluid.

    PubMed

    Qin, Xiaofa; Dong, Wei; Sharpe, Susan M; Sheth, Sharvil U; Palange, David C; Rider, Therese; Jandacek, Ronald; Tso, Patrick; Deitch, Edwin A

    2012-10-15

    Recent studies have shown that mesenteric lymph plays a very important role in the development of multiple-organ dysfunction syndrome under critical conditions. Great efforts have been made to identify the biologically active molecules in the lymph. We used a trauma-hemorrhagic shock (T/HS) model and the superior mesenteric artery occlusion (SMAO) model, representing a global and a localized intestinal ischemia-reperfusion insult, respectively, to investigate the role of free fatty acids (FFAs) in the cytotoxicity of mesenteric lymph in rats. Lymph was collected before, during, and after (post) shock or SMAO. The post-T/HS and SMAO lymph, but not the sham lymph, manifested cytotoxicity for human umbilical vein endothelial cells (HUVECs). HUVEC cytotoxicity was associated with increased FFAs, especially the FFA-to-protein ratio. Addition of albumin, especially delipidated albumin, reduced this cytotoxicity. Lipase treatment of trauma-sham shock (T/SS) lymph converted it from a noncytotoxic to a cytotoxic fluid, and its toxicity correlated with the FFA-to-protein ratio in a fashion similar to that of the T/HS lymph, further suggesting that FFAs were the key components leading to HUVEC cytotoxicity. Analysis of lymph by gas chromatography revealed that the main FFAs in the post-T/HS or lipase-treated T/SS lymph were palmitic, stearic, oleic, and linoleic acids. When added to the cell culture at levels comparable to those in T/HS lymph, all these FFAs were cytotoxic, with linoleic acid being the most potent. In conclusion, this study suggests that lipase-generated FFAs are the key components resulting in the cytotoxicity of T/HS and SMAO mesenteric lymph. PMID:22899820

  7. Regulation of the interplanetary magnetic flux

    SciTech Connect

    McComas, D.J.; Gosling, J.T.; Phillips, J.L.

    1991-01-01

    In this study we use a recently developed technique for measuring the 2-D magnetic flux in the ecliptic plane to examine (1) the long term variation of the magnetic flux in interplanetary space and (2) the apparent rate at which coronal mass ejections (CMEs) may be opening new flux from the Sun. Since there is a substantial variation ({approximately}50%) of the flux in the ecliptic plane over the solar cycle, we conclude that there must be some means whereby new flux can be opened from the Sun and previously open magnetic flux can be closed off. We briefly describe recently discovered coronal disconnections events which could serve to close off previously open magnetic flux. CMEs appear to retain at least partial magnetic connection to the Sun and hence open new flux, while disconnections appear to be likely signatures of the process that returns closed flux to the Sun; the combination of these processes could regulate the amount of open magnetic flux in interplanetary space. 6 refs., 3 figs.

  8. Adipose tissue fatty acid metabolism during pregnancy in swine.

    PubMed

    McNamara, J P; Dehoff, M H; Collier, R J; Bazer, F W

    1985-08-01

    In vitro adipose tissue fatty acid pool size (POOL), fatty acid release (FAR) and esterification (EST) were measured in peritoneal (PFP) and subcutaneous mammary (MFP) fat pads of swine at d 15, 30, 45, 60, 75, 90, 105 and 112 of pregnancy. Plasma free fatty acids (FFA) and triglycerides (TG) were not altered by stage of pregnancy. Basal EST in PFP was generally constant across pregnancy with a peak at d 75. Basal EST in MFP was elevated at d 30, 75 and 112. Esterification in response to norepinephrine stimulus (NE) was lower than basal rates in both fat depots. Basal FAR was constant throughout pregnancy in PFP, but elevated at d 75 and 90 in MFP. Fatty acid release in response to NE was biphasic with peaks at d 30 and in late pregnancy (in MFP, micromolar FAR in response to NE was 69.3% greater on d 75 to 112 than on d 45 to 60). Basal POOL was constant throughout pregnancy in both depots and lower than NE-stimulated POOL. All responses to NE were greater in MFP than in PFP, indicating that adipose tissue surrounding the developing mammary gland had higher metabolic activity and a greater response to NE than peritoneal adipose. Changes in fatty acid metabolism during pregnancy in swine are temporally related to published values for plasma steroids, fetal growth and mammary development. Metabolic adaptations in adipose and mannary epithelial tissue occur in synchrony with changing plasma estrogen concentrations, redirecting energy flow from maternal adipose tissue toward developing mammary and fetal tissue. PMID:4044440

  9. How the Saturnian Magnetosphere Conserves Magnetic Flux

    NASA Astrophysics Data System (ADS)

    Powell, R. L.; Wei, H.; Russell, C. T.; Arridge, C. S.; Dougherty, M. K.

    2012-12-01

    The magnetospheric dynamics at Saturn are driven by the centrifugal force of near co-rotating water group ions released at a rate of hundreds of kilograms per second by Saturn's moon Enceladus. The plasma is accelerated up to co-rotation speed by the magnetospheric magnetic field coupled to the Saturnian ionosphere. The plasma is lost ultimately through the process of magnetic reconnection in the tail. Conservation of magnetic flux requires that plasma-depleted, "empty" flux tubes return magnetic flux to the inner magnetosphere. After completion of the initial inrush of the reconnected and largely emptied flux tubes inward of the reconnection point, the flux tubes face the outflowing plasma and must move inward against the flow. Observations of such flux tubes have been identified in the eight years of Cassini magnetometer data. The occurrence of these tubes is observed at all local times indicating slow inward transport of the tubes relative to the co-rotation speed. Depleted flux tubes observed in the equatorial region appear as an enhancement in the magnitude of the magnetic field, whereas the same flux tubes observed at higher latitudes appear as decreased field strength. The difference in appearance of the low latitude and the high latitude tubes is due to the plasma environment just outside the tube. Warm low-density plasma fills the inside of the flux tube at all latitudes. This flux tube thus will expand in the less dense regions away from the magnetic equator and will be observed as a decrease in the magnitude of the magnetic field from the background. These flux tubes near the equator, where the plasma density outside of the flux tube is much greater, will be observed as an enhancement in the magnitude of the magnetic field. Cassini magnetometer and CAPS data are examined to understand the properties of these flux tubes and their radial and latitudinal evolution throughout the Saturnian magnetospheric environment.

  10. Insects, infestations and nutrient fluxes

    NASA Astrophysics Data System (ADS)

    Michalzik, B.

    2012-04-01

    Forest ecosystems are characterized by a high temporal and spatial variability in the vertical transfer of energy and matter within the canopy and the soil compartment. The mechanisms and controlling factors behind canopy processes and system-internal transfer dynamics are imperfectly understood at the moment. Seasonal flux diversities and inhomogeneities in throughfall composition have been reported from coniferous and deciduous forests, and in most cases leaf leaching has been considered as principle driver for differences in the amount and quality of nutrients and organic compounds (Tukey and Morgan 1963). Since herbivorous insects and the processes they initiate received less attention in past times, ecologists now emphasize the need for linking biological processes occurring in different ecosystem strata to explain rates and variability of nutrient cycling (Bardgett et al. 1998, Wardle et al. 2004). Consequently, herbivore insects in the canopies of forests are increasingly identified to play an important role for the (re)cycling and availability of nutrients, or, more generally, for the functioning of ecosystems not only in outbreak situations but also at endemic (non-outbreak) density levels (Stadler et al. 2001, Hunter et al. 2003). Before, little attention was paid to insect herbivores when quantifying element and energy fluxes through ecosystems, although the numerous and different functions insects fulfill in ecosystems (e.g. as pollinators, herbivores or detritivores) were unanimously recognized (Schowalter 2000). Amongst the reasons for this restraint was the argument that the total biomass of insects tends to be relatively low compared to the biomass of trees or the pool of soil organic matter (Ohmart et al. 1983). A second argument which was put forward to justify the inferior role of insects in nutrient cycling were the supposed low defoliation losses between 5-10% of the annual leaf biomass, or net primary production, due to insect herbivory under

  11. Annihilation of Quantum Magnetic Fluxes

    NASA Astrophysics Data System (ADS)

    Gonzalez, W. D.

    After introducing the concepts associated with the Aharonov and Bohm effect and with the existence of a quantum of magnetic flux (QMF), we briefly discuss the Ginzburg-Landau theory that explains its origin and fundamental consequences. Also relevant observations of QMFs obtained in the laboratory using superconducting systems (vortices) are mentioned. Next, we describe processes related with the interaction of QMFs with opposite directions in terms of the gauge field geometry related to the vector potential. Then, we discuss the use of a Lagrangian density for a scalar field theory involving radiation in order to describe the annihilation of QMFs, claimed to be responsible for the emission of photons with energies corresponding to that of the annihilated magnetic fields. Finally, a possible application of these concepts to the observed variable dynamics of neutron stars is briefly mentioned.

  12. Hypercharge flux in heterotic compactifications

    NASA Astrophysics Data System (ADS)

    Anderson, Lara B.; Constantin, Andrei; Lee, Seung-Joo; Lukas, Andre

    2015-02-01

    We study heterotic Calabi-Yau models with hypercharge flux breaking, where the visible E8 gauge group is directly broken to the standard model group by a nonflat gauge bundle, rather than by a two-step process involving an intermediate grand unified theory and a Wilson line. It is shown that the required alternative E8 embeddings of hypercharge, normalized as required for gauge unification, can be found and we classify these possibilities. However, for all but one of these embeddings we prove a general no-go theorem which asserts that no suitable geometry and vector bundle leading to a standard model spectrum can be found. Intuitively, this happens due to the large number of index conditions which have to be imposed in order to obtain a correct physical spectrum in the absence of an underlying grand unified theory.

  13. Observations of flux transfer events

    NASA Astrophysics Data System (ADS)

    Farrugia, C. J.; Southwood, D. J.; Cowley, S. W. H.

    A decade of research on flux transfer events (FTEs) has supported their interpretation as signatures of reconnection between the solar and terrestrial magnetic fields. Some of the observational evidence is reviewed. Another observational signature of reconnection has been studied in the literature: high speed plasma flows satisfying approximately stress balance calculations. A well-documented crossing of the magnetopause is revisited to show how these signatures, which are prima facie so diverse and which have hitherto been studied in isolation, can be understood in terms of unsteady Petschek reconnection occurring at the magnetopause. A review of some works on FTEs using data from the AMPTE spacecraft highlights the advances made possible by that mission.

  14. Chaos in Magnetic Flux Ropes

    NASA Astrophysics Data System (ADS)

    Gekelman, Walter; DeHaas, T.; Van Compernolle, B.; Vincena, S.

    2013-07-01

    Magnetic Flux Ropes Immersed in a uniform magnetoplasma are observed to twist about themselves, writhe about each other and rotate about a central axis. They are kink unstable and smash into one another as they move. Each collision results in magnetic field line generation and the generation of a quasi-seperatrix layer. Three dimensional magnetic field lines are computed by conditionally averaging the data using correlation techniques. When the currents associated with the ropes are large,this is possible for only a number of rotation cycles as the field line motion becomes chaotic. The permutation entropy1 can be calculated from the the time series of the magnetic field data (this is also done with flows) and used to calculate the positions of the data on a Jensen Shannon complexity map2. The power spectra of much of the magnetic and flow data is exponential and Lorentzian structures in the time domain are embedded in them. The location of data on this map indicates if the magnetic fields are stochastic, or fall into regions of minimal or maximal complexity. The complexity is a function of space and time. The complexity map, and analysis will be explained in the course of the talk. Other types of chaotic dynamical models such as the Lorentz or Gissinger process also fall on the map and can give a clue to the nature of the flux rope turbulence. The ropes fall in the region of the C-H plane where chaotic systems lie. 1 C. Bandt, B. Pompe, Phys. Rev. Lett., 88,174102 (2007) 2 O. Russo et al., Phys. Rev. Lett., 99, 154102 (2007), J. Maggs, G.Morales, “Permutation Entropy analysis of temperature fluctuations from a basic electron heat transport experiment”,submitted PPCF (2013)

  15. Amino acids

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

  16. Mefenamic Acid

    MedlinePlus

    Mefenamic acid is used to relieve mild to moderate pain, including menstrual pain (pain that happens before or during a menstrual period). Mefenamic acid is in a class of medications called NSAIDs. ...

  17. Aminocaproic Acid

    MedlinePlus

    Aminocaproic acid is used to control bleeding that occurs when blood clots are broken down too quickly. This type ... the baby is ready to be born). Aminocaproic acid is also used to control bleeding in the ...

  18. Ascorbic Acid

    MedlinePlus

    Ascorbic acid is used to prevent and treat scurvy, a disease caused by a lack of vitamin C in ... Ascorbic acid comes in extended-release (long-acting) capsules and tablets, lozenges, syrup, chewable tablets, and liquid drops to ...

  19. Acid mucopolysaccharides

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003368.htm Acid mucopolysaccharides To use the sharing features on this page, please enable JavaScript. Acid mucopolysaccharides is a test that measures the amount ...

  20. Ethacrynic Acid

    MedlinePlus

    Ethacrynic acid, a 'water pill,' is used to treat swelling and fluid retention caused by various medical problems. It ... Ethacrynic acid comes as a tablet to take by mouth. It is usually taken once or twice a day ...

  1. The role of trace gas flux networks in biogeosciences

    SciTech Connect

    Baldocch, Dennis; Reichstein, Markus; Papale, D.; Koteen, Laurie; Vargas, Rodrigo; Agarwal, D. A.; Cook, Robert B.

    2012-01-01

    Vast networks of meteorological sensors ring the globe, providing continuous measurements of an array of atmospheric state variables such as temperature, humidity, rainfall, and the concentration of carbon dioxide [New etal., 1999; Tans etal., 1996]. These measurements provide input to weather and climate models and are key to detecting trends in climate, greenhouse gases, and air pollution. Yet to understand how and why these atmospheric state variables vary in time and space, biogeoscientists need to know where, when, and at what rates important gases are flowing between the land and the atmosphere. Tracking trace gas fluxes provides information on plant or microbial metabolism and climate-ecosystem interactions. The existence of trace gas flux networks is a relatively new phenomenon, dating back to research in 1984. The first gas flux measurement networks were regional in scope and were designed to track pollutant gases such as sulfur dioxide, ozone, nitric acid, and nitrogen dioxide. Atmospheric observations and model simulations were used to infer the depositional rates of these hazardous chemicals [Fowler etal., 2009; Meyers etal., 1991]. In the late 1990s, two additional trace gas flux measurement networks emerged. One, the United States Trace Gas Network (TRAGNET), was a short-lived effort that measured trace gas emissions from the soil and plants with chambers distributed throughout the country [Ojima etal., 2000]. The other, FLUXNET, was an international endeavor that brought many regional networks together to measure the fluxes of carbon dioxide, water vapor, and sensible heat exchange with the eddy covariance technique [Baldocchi etal., 2001]. FLUXNET, which remains active today, currently includes more than 400 tower sites, dispersed across most of the world's climatic zones and biomes, with sites in North and South America, Europe, Asia, Africa, and Australia. More recently, several specialized networks have emerged, including networks dedicated to

  2. ENSO Related Variations in the Flux and Labile Composition of Settling Particles in the Western Equatorial Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Gupta, L. P.; Kawahata, H.; Kawahata, H.

    2001-12-01

    Sediment trap moorings deployed in three distinct oceanographic zones along the equator in the western Pacific Ocean during 1991-93, 1994-95 and 1999 provided time series data on total mass and amino acid fluxes and composition of settling particulate organic matter (POM). The traps were deployed at shallow (970-1769 m) and deep (2060-4574 m) water depths, where seafloor depth ranged from 3181 to 4888 m, to collect settling particles over an interval of about 12-16 days. An intercomparison of annual averages of various parameters revealed discrete patterns in flux and composition of POM under the El Nino (1991-93, 1994-95) and La Nina (1999) conditions which prevailed over the equatorial Pacific during this experiment. In the hemipelagic zone of the far western equatorial Pacific, average total mass and amino acid fluxes were relatively higher during El Nino than during La Nina. However, in the oligotrophic warm pool and upwelling sites, total mass and amino acid fluxes were higher during La Nina. Influence of ENSO-related changes in the settling particle flux was much clearer in the hemipelagic zone compared to that in the warm pool. Average values of biogeochemical parameters such as mole ratios of Glucosamine/Galactosamine and amino acid/hexosamine, and bulk parameters like amino acid carbon and nitrogen contents relative to organic carbon and total nitrogen (THAA-C% and THAA-N%, respectively), and organic carbon normalized amino acid concentrations indicated that settling POM was more labile during La Nina at all the sites. The mole ratios Aspartic acid/beta-Alanine, Glutamic acid/gama-Aminobutyric acid, and relative mole concentration of non-protein amino acids (beta-Alanine + gama-Aminobutyric acid) suggested that POM degradation was enhanced during La Nina than during El Nino conditions at all sites.

  3. Influence of exogenous ATP on blood sugar, serum insulin and serum free fatty acids in short-term experimental hyperthyroid dogs and in euthyroid controls.

    PubMed

    Renauld, A; Sverdlik, R C

    1989-01-01

    We studied the influence of ATP administration on blood sugar (BS), serum immunoreactive insulin (IRI) and serum free fatty acid (FFA) responses to glucose-induced hyperglycemia in short-term experimental hyperthyroid (STEH) dogs and in euthyroid controls. Hyperthyroidism was induced by a 10-day s.c. treatment with 100 micrograms/kg body weight 1-thyroxine. Glucose challenge was performed by i.v. infusion (700 mg/kg body weight as a priming dose, followed by 20 mg/kg body weight/min for 60 min). ATP (1 mg/kg body weight/min) was infused for 100 min 40 min before and 60 min during glucose administration). Glucose-induced hyperglycemia was more prolonged in the hyperthyroid group. ATP treatment did not affect the BS profile of controls but raised that of STEH animals. In the normal controls the insulinemic response to hyperglycemia was enhanced during ATP infusion. By contrast, in the STEH dogs insulin levels during glucose infusion was lower than in controls and did not significantly increase when ATP was added. ATP infusion induced a significant elevation of serum FFA, which was more pronounced in hyperthyroid animals with a greater fall during glucose administration and a marked increase during the period of recovery from hyperglycemia. In conclusion, we postulate that short-term hyperthyroidism in dogs may inhibit adenylate cyclase function in pancreatic B-cells and chiefly stimulate the action of cAMP-phosphodiesterase activity, thereby affecting insulin secretion. PMID:2698040

  4. Pyrolytic graphite gauge for measuring heat flux

    NASA Technical Reports Server (NTRS)

    Bunker, Robert C. (Inventor); Ewing, Mark E. (Inventor); Shipley, John L. (Inventor)

    2002-01-01

    A gauge for measuring heat flux, especially heat flux encountered in a high temperature environment, is provided. The gauge includes at least one thermocouple and an anisotropic pyrolytic graphite body that covers at least part of, and optionally encases the thermocouple. Heat flux is incident on the anisotropic pyrolytic graphite body by arranging the gauge so that the gauge surface on which convective and radiative fluxes are incident is perpendicular to the basal planes of the pyrolytic graphite. The conductivity of the pyrolytic graphite permits energy, transferred into the pyrolytic graphite body in the form of heat flux on the incident (or facing) surface, to be quickly distributed through the entire pyrolytic graphite body, resulting in small substantially instantaneous temperature gradients. Temperature changes to the body can thereby be measured by the thermocouple, and reduced to quantify the heat flux incident to the body.

  5. Genome-scale metabolic flux analysis of Streptomyces lividans growing on a complex medium.

    PubMed

    D'Huys, Pieter-Jan; Lule, Ivan; Vercammen, Dominique; Anné, Jozef; Van Impe, Jan F; Bernaerts, Kristel

    2012-09-15

    Constraint-based metabolic modeling comprises various excellent tools to assess experimentally observed phenotypic behavior of micro-organisms in terms of intracellular metabolic fluxes. In combination with genome-scale metabolic networks, micro-organisms can be investigated in much more detail and under more complex environmental conditions. Although complex media are ubiquitously applied in industrial fermentations and are often a prerequisite for high protein secretion yields, such multi-component conditions are seldom investigated using genome-scale flux analysis. In this paper, a systematic and integrative approach is presented to determine metabolic fluxes in Streptomyces lividans TK24 grown on a nutritious and complex medium. Genome-scale flux balance analysis and randomized sampling of the solution space are combined to extract maximum information from exometabolome profiles. It is shown that biomass maximization cannot predict the observed metabolite production pattern as such. Although this cellular objective commonly applies to batch fermentation data, both input and output constraints are required to reproduce the measured biomass production rate. Rich media hence not necessarily lead to maximum biomass growth. To eventually identify a unique intracellular flux vector, a hierarchical optimization of cellular objectives is adopted. Out of various tested secondary objectives, maximization of the ATP yield per flux unit returns the closest agreement with the maximum frequency in flux histograms. This unique flux estimation is hence considered as a reasonable approximation for the biological fluxes. Flux maps for different growth phases show no active oxidative part of the pentose phosphate pathway, but NADPH generation in the TCA cycle and NADPH transdehydrogenase activity are most important in fulfilling the NADPH balance. Amino acids contribute to biomass growth by augmenting the pool of available amino acids and by boosting the TCA cycle, particularly

  6. Valproic Acid

    MedlinePlus

    Valproic acid is used alone or with other medications to treat certain types of seizures. Valproic acid is also used to treat mania (episodes of ... to relieve headaches that have already begun. Valproic acid is in a class of medications called anticonvulsants. ...

  7. Differential effect of saturated and polyunsaturated fatty acids on hepatic glucose metabolism in humans.

    PubMed

    Clore, John N; Stillman, Julie S; Li, Jing; O'Keefe, Stephen J D; Levy, James R

    2004-08-01

    Prolonged infusions of lipid and heparin that achieve high physiological free fatty acid (FFA) concentrations inhibit hepatic (and peripheral) insulin sensitivity in humans. These infusions are composed largely of polyunsaturated fatty acids (PUFA; linoleic and linolenic). It is not known whether fatty acid composition per se affects hepatic glucose metabolism in humans. To address this issue, we examined the impact of enteral infusions of either palm oil (48% palmitic, 35% oleic, and 8% linoleic acids) or safflower oil (6% palmitic, 12% oleic, 74% linoleic acids) in 14 obese nondiabetic subjects. (2)H(2)O was administered to determine the contribution of gluconeogenesis to endogenous glucose production (EGP), and a primed continuous infusion of [6,6-(2)H]glucose was administered to assess glucose appearance. As a result of the lipid infusions, plasma FFA concentrations increased significantly in both the palm oil (507.5 +/- 47.4 to 939.3 +/- 61.3 micromol/l, P < 0.01) and safflower oil (588.2.0 +/- 43.0 to 857.8 +/- 68.7 micromol/l, P < 0.01) groups after 4 h. EGP was similar at baseline (12.4 +/- 1.8 vs. 11.2 +/- 1.0 micromol x kg FFM(-1) x min(-1)). During a somatostatin-insulin clamp, the glucose infusion rate was significantly lower (AUC glucose infusion rate 195.8 +/- 50.7 vs. 377.8 +/- 38.0 micromol/kg FFM, P < 0.01), and rates of EGP were significantly higher (10.7 +/- 1.4 vs. 6.5 +/- 1.5 micromol x kg FFM(-1) x min(-1), P < 0.01) after palm oil compared with safflower oil, respectively. Baseline rates of gluconeogenesis and glycogenolysis were also similar. However, after lipid infusion, rates of glycogenolysis were suppressed by safflower oil but not by palm oil. Thus these studies demonstrate, for the first time in humans, a differential effect of saturated fatty acids and PUFA on hepatic glucose metabolism. PMID:15082421

  8. Chloride flux out of Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    Norton, Daniel R.; Friedman, Irving

    1985-12-01

    Monitoring of the chloride concentration, electrical conductivity, and discharge was carried out for the four major rivers of Yellowstone National Park from September 1982 to January 1984. Chloride flux out of the Park was determined from the measured values of chloride concentration and discharge. The annual chloride flux from the Park was 5.86 × 10 10 g. Of this amount 45% was from the Madison River drainage basin, 32% from the Yellowstone River basin, 12% from the Snake River basin, and 11% from the Falls River basin. Of the annual chloride flux from the Yellowstone River drainage basin 36% was attributed to the Yellowstone Lake drainage basin. The geothermal contribution to the chloride flux was determined by subtracting the chloride contribution from rock weathering and atmospheric precipitation and is 94% of the total chloride flux. Calculations of the geothermal chloride flux for each river are given and the implications of an additional chloride flux out of the western Park boundary discussed. An anomalous increase in chloride flux out of the Park was observed for several weeks prior to the Mt. Borah earthquake in Central Idaho on October 28, 1983, reaching a peak value shortly thereafter. It is suggested that the rise in flux was a precursor of the earthquake. The information in this paper provides baseline data against which future changes in the hydrothermal systems can be measured. It also provides measurements related to the thermal contributions from the different drainage basins of the Park.

  9. Parity-time symmetry under magnetic flux

    NASA Astrophysics Data System (ADS)

    Jin, L.; Song, Z.

    2016-06-01

    We study a parity-time-(PT -) symmetric ring lattice, with one pair of balanced gain and loss located at opposite positions. The system remains PT -symmetric when threaded by a magnetic flux; however, the PT symmetry is sensitive to the magnetic flux in the presence of a large balanced gain and loss, or in a large system. We find a threshold gain or loss above which any nontrivial magnetic flux breaks the PT symmetry. We obtain the maximally tolerable magnetic flux for the exact PT -symmetric phase, which is approximately linearly dependent on a weak gain or loss.

  10. Fluxing agent for metal cast joining

    DOEpatents

    Gunkel, Ronald W.; Podey, Larry L.; Meyer, Thomas N.

    2002-11-05

    A method of joining an aluminum cast member to an aluminum component. The method includes the steps of coating a surface of an aluminum component with flux comprising cesium fluoride, placing the flux coated component in a mold, filling the mold with molten aluminum alloy, and allowing the molten aluminum alloy to solidify thereby joining a cast member to the aluminum component. The flux preferably includes aluminum fluoride and alumina. A particularly preferred flux includes about 60 wt. % CsF, about 30 wt. % AlF.sub.3, and about 10 wt. % Al.sub.2 O.sub.3.

  11. Charm contribution to the atmospheric neutrino flux

    NASA Astrophysics Data System (ADS)

    Halzen, Francis; Wille, Logan

    2016-07-01

    We revisit the estimate of the charm particle contribution to the atmospheric neutrino flux that is expected to dominate at high energies because long-lived high-energy pions and kaons interact in the atmosphere before decaying into neutrinos. We focus on the production of forward charm particles which carry a large fraction of the momentum of the incident proton. In the case of strange particles, such a component is familiar from the abundant production of K+Λ pairs. These forward charm particles can dominate the high-energy atmospheric neutrino flux in underground experiments. Modern collider experiments have no coverage in the very large rapidity region where charm forward pair production dominates. Using archival accelerator data as well as IceCube measurements of atmospheric electron and muon neutrino fluxes, we obtain an upper limit on forward D¯0Λc pair production and on the associated flux of high-energy atmospheric neutrinos. We conclude that the prompt flux may dominate the much-studied central component and represent a significant contribution to the TeV atmospheric neutrino flux. Importantly, it cannot accommodate the PeV flux of high-energy cosmic neutrinos, or the excess of events observed by IceCube in the 30-200 TeV energy range indicating either structure in the flux of cosmic accelerators, or a presence of more than one component in the cosmic flux observed.

  12. Chloride flux out of Yellowstone National Park

    USGS Publications Warehouse

    Norton, D.R.; Friedman, I.

    1985-01-01

    Monitoring of the chloride concentration, electrical conductivity, and discharge was carried out for the four major rivers of Yellowstone National Park from September 1982 to January 1984. Chloride flux out of the Park was determined from the measured values of chloride concentration and discharge. The annual chloride flux from the Park was 5.86 ?? 1010 g. Of this amount 45% was from the Madison River drainage basin, 32% from the Yellowstone River basin, 12% from the Snake River basin, and 11% from the Falls River basin. Of the annual chloride flux from the Yellowstone River drainage basin 36% was attributed to the Yellowstone Lake drainage basin. The geothermal contribution to the chloride flux was determined by subtracting the chloride contribution from rock weathering and atmospheric precipitation and is 94% of the total chloride flux. Calculations of the geothermal chloride flux for each river are given and the implications of an additional chloride flux out of the western Park boundary discussed. An anomalous increase in chloride flux out of the Park was observed for several weeks prior to the Mt. Borah earthquake in Central Idaho on October 28, 1983, reaching a peak value shortly thereafter. It is suggested that the rise in flux was a precursor of the earthquake. The information in this paper provides baseline data against which future changes in the hydrothermal systems can be measured. It also provides measurements related to the thermal contributions from the different drainage basins of the Park. ?? 1985.

  13. Helical flux ropes in solar prominences

    NASA Technical Reports Server (NTRS)

    Martens, P. C. H.; Van Ballegooijen, A. A.

    1990-01-01

    The present numerical method for the computation of force-free, cancelling magnetic structures shows that flux cancellation at the neutral line in a sheared magnetic arcade generates helical field lines that can support a prominence's plasma. With increasing flux cancellation, the axis of the helical fields moves to greater heights; this is suggestive of a prominence eruption. Two alternative scenarios are proposed for the formation of polar crown prominences which yield the correct axial magnetic field sign. Both models are noted to retain the formation of helical flux tubes through flux cancellation as their key feature.

  14. Siphon flows in isolated magnetic flux tubes

    NASA Technical Reports Server (NTRS)

    Thomas, John H.

    1988-01-01

    The paper considers steady siphon flows in isolated thin magnetic flux tubes surrounded by field-free gas, with plasma beta greater than or equal to 1, appropriate for conditions in the solar photosphere. The cross-sectional area of the flux tube varies along the tube in response to pressure changes induced by the siphon flow. Consideration is also given to steady isothermal siphon flows in arched magnetic flux tubes in a stratified atmosphere. Applications of the results to intense magnetic flux tubes in the solar photosphere and to the photospheric Evershed flow in a sunspot penumbra are addressed.

  15. Effect of Saturated Very Long-Chain Fatty Acids on the Organization of Lipid Membranes: A Study Combining (2)H NMR Spectroscopy and Molecular Dynamics Simulations.

    PubMed

    Paz Ramos, Adrian; Lagüe, Patrick; Lamoureux, Guillaume; Lafleur, Michel

    2016-07-21

    Little is known about the interaction of very long-chain saturated fatty acids (VLCFAs) with biological membranes. However, this could play an important role on interleaflet interactions and signal transduction mechanisms in cells. The aim of this work is to determine how VLCFA structurally adapts in fluid phospholipid bilayers, since both species must exhibit a significant hydrophobic mismatch. The membrane organization has been described by means of (2)H NMR and molecular dynamics simulations. Our results show that the protonation state affects the position and order of free fatty acids (FFAs) in phospholipid membranes. It was shown that the protonated FFA-C24 carboxyl group is located slightly under the POPC head group and therefore its acyl chain can interact with the lipids of the opposite leaflet. This interdigitation of the end of the acyl chain causes a second plateau observed in SC-D profiles, a very unusual feature in lipid systems. PMID:27351151

  16. Episodic particle flux in the deep Sargasso Sea: an organic geochemical assessment

    NASA Astrophysics Data System (ADS)

    Conte, Maureen H.; Weber, J. C.; Ralph, Nathan

    1998-11-01

    Since 1978, the Oceanic Flux Program (OFP) time-series sediment trap study has continuously measured particle fluxes in the deep Sargasso Sea (31°50'N, 64°10'W). One feature of this 19+ year record has been the episodic occurrence of large, short-lived flux maxima that are not associated with the annual spring bloom. These maxima generally occur during the Dec.-Jan. period, but not necessarily every year. They have also occurred in other seasons. In January 1996, OFP traps located at 3200 and 3400 m depths intercepted a major flux "event" in which there was an abrupt, threefold increase in mass flux at both depths. Mass flux measured at 3200 m during the event (87 mg m -2 d -1) was the highest recorded since biweekly resolved sampling was begun in 1989. Organic biomarker analyses of material collected prior to, and during, this high flux event determined that there was an abrupt change in material composition associated with the sudden flux increase. Prior to the event, cholesterol, a single bacteriaderived C 27 hopanone (22,29,30-tris norhopan-21-one), and saturated and odd/branched fatty acids predominated: these compounds indicated that the sedimenting material was extensively degraded. During the event, organic material was greatly enriched in C 26-C 29 phytosterols, haptophyte algae-derived C 37-C 39 alkenones, labile polyunsaturated acids, degradation products such as steroidal ketones, and also in bacteria-derived compounds such as C 27-C 34 hopanoids and β and ω-1 hydroxy acids. These compounds indicated the organic fraction contained a large amount of relatively fresh phytoplankton-derived debris and tracers of bacterial biomass and metabolism, which suggested that the sinking material was undergoing active bacterial decomposition. Thus, the flux "event" appears to have resulted from a shortlived bloom in the overlying surface waters which, for reasons not currently apparent, was inefficiently remineralized in the upper ocean and rapidly settled to

  17. Crossover of formic acid through Nafion ® membranes

    NASA Astrophysics Data System (ADS)

    Rhee, Young-Woo; Ha, Su Y.; Masel, Richard I.

    Formic acid has been proposed as a possible fuel for miniature fuel cells, because formic acid is expected to show low crossover and easy water management. In this paper, the permeation of formic acid through Nafion ® membranes is investigated at room temperature. It is found that the permeation of formic acid through Nafion ® 112 and 117 is much lower than that of methanol. For example, at a 1 M concentration, the steady state flux of formic acid through Nafion ® 117 is only 2.03±0.07×10 -8 mol/cm 2 s. By comparison, previous workers have observed a methanol flux of 3 to 6×10 -6 mol/cm 2 s through Nafion ® 117 under similar conditions. The flux through Nafion ® 117 increases with increasing formic acid concentration, reaching a maximum of 1.86±0.11×10 -7 mol/cm 2 s at a formic acid concentration of 10 M. The flux of formic acid is about a factor of two higher through Nafion ® 112 than through Nafion ® 117 but still low. These results show that the permeation of formic acid through Nafion ® is much slower than the permeation of methanol through the same membrane. Consequently, formic acid is an attractive alternative fuel for small polymer electrolyte membrane (PEM) fuel cells.

  18. Self-organization in magnetic flux ropes

    NASA Astrophysics Data System (ADS)

    Lukin, Vyacheslav S.

    2014-06-01

    This cross-disciplinary special issue on 'Self-organization in magnetic flux ropes' follows in the footsteps of another collection of manuscripts dedicated to the subject of magnetic flux ropes, a volume on 'Physics of magnetic flux ropes' published in the American Geophysical Union's Geophysical Monograph Series in 1990 [1]. Twenty-four years later, this special issue, composed of invited original contributions highlighting ongoing research on the physics of magnetic flux ropes in astrophysical, space and laboratory plasmas, can be considered an update on our state of understanding of this fundamental constituent of any magnetized plasma. Furthermore, by inviting contributions from research groups focused on the study of the origins and properties of magnetic flux ropes in a variety of different environments, we have attempted to underline both the diversity of and the commonalities among magnetic flux ropes throughout the solar system and, indeed, the universe. So, what is a magnetic flux rope? The answer will undoubtedly depend on whom you ask. A flux rope can be as narrow as a few Larmor radii and as wide as the Sun (see, e.g., the contributions by Heli Hietala et al and by Angelous Vourlidas). As described below by Ward Manchester IV et al , they can stretch from the Sun to the Earth in the form of interplanetary coronal mass ejections. Or, as in the Swarthmore Spheromak Experiment described by David Schaffner et al , they can fit into a meter-long laboratory device tended by college students. They can be helical and line-tied (see, e.g., Walter Gekelman et al or J Sears et al ), or toroidal and periodic (see, e.g., John O'Bryan et al or Philippa Browning et al ). They can form in the low plasma beta environment of the solar corona (Tibor Török et al ), the order unity beta plasmas of the solar wind (Stefan Eriksson et al ) and the plasma pressure dominated stellar convection zones (Nicholas Nelson and Mark Miesch). In this special issue, Setthivoine You

  19. Kruppel-like factor 15 regulates skeletal muscle lipid flux and exercise adaptation

    PubMed Central

    Haldar, Saptarsi M.; Jeyaraj, Darwin; Anand, Priti; Zhu, Han; Lu, Yuan; Prosdocimo, Domenick A.; Eapen, Betty; Kawanami, Daiji; Okutsu, Mitsuharu; Brotto, Leticia; Fujioka, Hisashi; Kerner, Janos; Rosca, Mariana G.; McGuinness, Owen P.; Snow, Rod J.; Russell, Aaron P.; Gerber, Anthony N