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Relevant bibliographies by topics / Linoleate

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Academic literature on the topic 'Linoleate'

Author: Grafiati

Published: 4 June 2021

Last updated: 3 February 2022

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Journal articles on the topic "Linoleate"

1

Chen, Zhen-Yu, Chantale R. Menard, and Stephen C. Cunnane. "Accumulation of polyunsaturates is decreased by weight-cycling: whole-body analysis in young, growing rats." British Journal of Nutrition 75, no. 4 (April 1996): 583–91. http://dx.doi.org/10.1079/bjn19960161.

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Whole-body fatty acid analysis in rats has previously shown that 50–70% of dietary linoleate and α-linolenate is β-oxidized to CO2 and that this value increases with refeeding after a single episode of fasting. Our hypothesis was that repeated fasting-refeeding or weight-cycling would increase the β-oxidation of linoleate and α-linolenate thereby depleting their whole-body levels. In rats consuming 3% energy as linoleate and 0·15 % energy as α-linolenate during a 16 d balance period, 19% of the linoleate consumed accumulated in weight-cycled rats compared with 34% in the free-fed controls (P < 0.01). Similarly, 11% of the α-linolenate consumed accumulated in the weight-cycled rats compared with 22% in the controls (P < 0.01). Arachidonate and docosahexaenoate also accumulated to lower extents in the weight-cycled rats than in the controls. In contrast, whole-body accumulation of palmitate, stearate and oleate was not different between the weight-cycled group and the controls when measured as a proportion of intake or relative to weight gain. Thus, whole-body depletion of linoleate and α-linolenate did not occurper se but the partitioning of linoleate and α-linolenate was significantly altered by weight-cycling resulting in lower whole-body accumulation and higher apparent oxidation of all polyunsaturates especially linoleate and α-linolenate.

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2

Stymne, S., and A. K. Stobart. "Biosynthesis of γ-linolenic acid in cotyledons and microsomal preparations of the developing seeds of common borage (Borago officinalis)." Biochemical Journal 240, no. 2 (December 1, 1986): 385–93. http://dx.doi.org/10.1042/bj2400385.

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The developing seeds of Borago officinalis (common borage) accumulate a triacylglycerol oil that is relatively rich in the uncommon fatty acid gamma-linolenate (octadec-6,9,12-trienoic acid). Incubation of developing, whole, cotyledons with [14C]oleate and [14C]linoleate showed that the gamma-linolenate was synthesized by the sequential desaturation of oleate—linoleate—gamma-linolenate. Microsomal membrane preparations from the developing cotyledons contained an active delta 6-desaturase enzyme that catalysed the conversion of linoleate into gamma-linolenate. Experiments were designed to manipulate the [14C]linoleate content of the microsomal phosphatidylcholine. The [14C]linoleoyl phosphatidylcholine labelled in situ was converted into gamma-linolenoyl phosphatidylcholine in the presence of NADH. The substrate for the delta 6-desaturase in borage was, therefore, the linoleate in the complex microsomal lipid phosphatidylcholine, rather than, as in animals, the acyl-CoA. This was further confirmed in experiments that compared the specific radioactivity of the gamma-linolenate, in acyl-CoA and phosphatidylcholine, that was synthesized when [14C]linoleoyl-CoA was incubated with microsomal membranes, NADH and non-radioactive gamma-linolenoyl-CoA. The delta 6-desaturase was positionally specific and only utilized the linoleate in position 2 of sn-phosphatidylcholine. Analysis of the positional distribution of fatty acids in the endogenous microsomal sn-phosphatidylcholine showed that, whereas position 1 contained substantial linoleate, only small amounts of gamma-linolenate were present. The results shed further light on the synthesis of C18 polyunsaturated fatty acids in plants and in particular its relationship to the regulation of the acyl quality of the triacylglycerols in oilseeds.

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3

Chen, Z. Y., C. R. Menard, and S. C. Cunnane. "Moderate, selective depletion of linoleate and alpha-linolenate in weight-cycled rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 268, no. 2 (February 1, 1995): R498—R505. http://dx.doi.org/10.1152/ajpregu.1995.268.2.r498.

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In rats, the response of adipose tissue composition to a single weight cycle (24-48 h of fasting followed by refeeding) is characterized by a decrease primarily in linoleate and alpha-linolenate, with little or no change in other fatty acids. We tested the hypothesis that during successive weight cycles caused by repeated fasting and refeeding, the depletion of linoleate and alpha-linolenate from whole body stores would be exacerbated despite their adequate availability during the refeeding period. Four complete weight cycles (24-h fasting followed by 72-h ad libitum refeeding) induced a significant quantitative decrease in total n-3 and n-6 polyunsaturates, particularly linoleate and alpha-linolenate, and a simultaneous increase in the accumulation of palmitate, palmitoleate, and oleate in carcass total lipids and in perirenal and epididymal adipose tissue. A significant positive relationship was observed between the increasing ratio of saturates+monounsaturates to n-3 + n-6 polyunsaturates in adipose tissue and the number of weight cycles (r = +0.96, P < 0.0001). The percentage of linoleate and alpha-linolenate in adipose tissue was inversely related to the number of weight cycles. We conclude that, despite providing adequate n-6 and n-3 polyunsaturates in the diet during the refeeding period, weight cycling in young growing rats causes a moderate, selective depletion of linoleate and alpha-linolenate from tissue stores.

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4

Cunnane, S. C., and J. Yang. "Zinc deficiency impairs whole body accumulation of polyunsaturates and increases the utilization of [1-14C]linoleate for de novo lipid synthesis in pregnant rats." Canadian Journal of Physiology and Pharmacology 73, no. 9 (September 1, 1995): 1246–52. http://dx.doi.org/10.1139/y95-176.

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Zinc deficiency impairs the metabolism of polyunsaturates, but the degree to which its effects are independent of food intake are still in question. Identical amounts of a semiliquid control diet (26.4 mg zinc/kg) or moderately zinc deficient diet (3.2 mg zinc/kg) were tube fed to rats for 11 days during the second half of pregnancy to evaluate the specific effects of zinc deficiency on maternal utilization and fetal accumulation of polyunsaturates. The whole body fatty acid balance method was used to determine net accumulation of polyunsaturates and their whole-body disappearance. Incorporation of 14C from [1-14C]linoleate into maternal and fetal lipid classes was also studied on days 20–21. At term, zinc-deficient rats had significantly higher whole-body disappearance of linoleate and α-linolenate and lower accumulation of n−6 and n−3 long-chain polyunsaturates. Zinc-deficient rats had higher 14C activity in free cholesterol, saturates, and monounsaturates in several maternal organs but not in the fetuses. We conclude that during pregnancy, moderate zinc deficiency not affecting food intake or weight gain still alters whole-body metabolism of linoleate and α-linolenate towards increased β-oxidation and also increases the utilization of carbon from linoleate for de novo lipid synthesis.Key words: cholesterol, linoleate, α-linolenate, oxidation, polyunsaturates, pregnancy, zinc.

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5

Chen, Z. Y., M. M. Sea, K. Y. Kwan, Y. H. Leung, and P. F. Leung. "Depletion of linoleate induced by weight cycling is independent of extent of calorie restriction." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 272, no. 1 (January 1, 1997): R43—R50. http://dx.doi.org/10.1152/ajpregu.1997.272.1.r43.

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Recent epidemiological studies have suggested that weight cycling induced by repeated dieting over time may increase the risk of cardiovascular disease. It is speculated that the increased mortality from coronary heart disease for people with a history of excessive weight cycling could be attributed to change in lipid metabolism. Previous studies have demonstrated that repeated cycling of 100% food restriction followed by ad libitum refeeding caused a depletion of linoleate and alpha-linolenate in rats. The objective of the present study was to test the hypothesis that the weight cycling-induced reduction in linoleate and alpha-linolenate is independent of extent of calorie restriction. Two consecutive weight cycles in three experiments were induced by 100% calorie restriction, 60% calorie restriction, and 36% calorie restriction, respectively, followed by ad libitum refeeding. As the consequence of the two weight cycles, linoleate and linolenate were decreased, whereas myristate, palmitate, and palmitoleate were proportionally increased in carcass and adipose tissue lipids. The results of all three experiments showed a preferential depletion of linoleate and alpha-linolenate without changes in final body weight, total body fat, and adipose tissue pads in the weight-cycled rats. In addition, the triacylglycerol species profile in the adipose tissue of weight-cycled rats was significantly remodeled, with a proportional depletion of linoleate-enriched triacylglycerol species (LLL, LLO, and LLP, where L, O, and P are linoleic, oleic, and palmitic acid, respectively) and a proportional accumulation of palmitate-enriched triacylglycerol species (OPPo, PPPo, and PPP, where Po is palmitoleic acid). We conclude that weight cycling changes the ratio of polyunsaturated fatty acids to saturated fatty acids and remodels the adipose tissue triacylglycerol species profile in rats.

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6

Cunnane, Stephen C. "The conditional nature of the dietary need for polyunsaturates: a proposal to reclassify ‘essential fatty acids’ as ‘conditionally-indispensable’ or ‘conditionally-dispensable’ fatty acids." British Journal of Nutrition 84, no. 6 (December 2000): 803–12. http://dx.doi.org/10.1017/s0007114500002415.

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The term essential fatty acid no longer clearly identifies the fatty acids it was originally used to describe. It would be more informative if the concept of essentiality shifted away from the symptoms arising from the lack of de novo synthesis of linoleate or α-linolenate and towards the adequacy of the capacity for synthesis and conservation of both the parent and the derived long-chain polyunsaturates. For instance, despite the existence of the pathway for synthesis of docosahexaenoate from α-linolenate, the former would be more correctly classified as ‘conditionally indispensable’ because the capacity of the pathway appears insufficient during early development, although it may be sufficient later in life in healthy individuals. Similarly, despite the inability to synthesize linoleate de novo, abundant linoleate stores and its relatively slow turnover in healthy adults probably makes linoleate ‘conditionally dispensable’ for long periods. There are two other anomalies with the terms essential and non-essential fatty acids: (1) under several different experimental circumstances, the C-skeleton of essential fatty acids is avidly used in the synthesis of non-essential fatty acids; (2) to function normally, the brain is required to endogenously synthesize several non-essential fatty acids. As with essential amino acids, which have been reclassified as indispensable or conditionally indispensable, such a change in terminology should lead to an improved understanding of the function and metabolism of polyunsaturates in particular, and long-chain fatty acids in general.

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Griffiths, G., A. K. Stobart, and S. Stymne. "Δ 6- and Δ12-desaturase activities and phosphatidic acid formation in microsomal preparations from the developing cotyledons of common borage (Borago officinalis)." Biochemical Journal 252, no. 3 (June 15, 1988): 641–47. http://dx.doi.org/10.1042/bj2520641.

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Microsomal membrane preparations from the maturing cotyledons of common borage (Borago officinalis) exhibit delta 12- and delta 6-desaturase activities, which resulted in the synthesis of linoleate and gamma-linolenate respectively. The desaturase enzymes utilized the complex lipid substrate phosphatidylcholine. The activity of these enzymes was sufficiently high to allow the monitoring of the mass changes in the endogenous oleate, linoleate and gamma-linolenate in the microsomal phosphatidylcholine in the presence of NADH (i.e. under desaturating conditions). The results illustrate that the delta 12-desaturase uses the oleate substrate at both the sn-1 and -2 positions of sn-phosphatidylcholine, whereas the delta 6-desaturase is almost totally restricted to the linoleate at position 2 of the complex lipid. Estimate of the acyl-substrate pool size at position 2 of sn-phosphatidylcholine for both desaturases indicated that some 50% of the oleate and linoleate was available to the enzymes. The microsomes (microsomal fractions) had a somewhat impaired Kennedy [(1961) Fed. Proc. Fed. Am. Soc. Exp. Biol. 20, 934-940] pathway for the formation of triacylglycerols when compared with other oil-rich plant species that have been studied [Stymne & Stobart (1987) The Biochemistry of Plants: a Comprehensive Treatise (Stumpf, P.K., ed.), vol. 10, chapter 8, pp. 175-214, Academic Press, New York]. In the presence of sn-glycerol 3-phosphate and acyl-CoA, large quantities of phosphatidic acid accumulated in the membranes. Acyl-selectivity studies on the glycerol-acylating enzymes showed that gamma-linolenate could be acylated to both the sn-1 and sn-2 positions of sn-glycerol 3-phosphate. However, stereochemical analysis of the acyl components of the sn-triacylglycerol obtained from mature seeds indicated that, whereas no gamma-linolenate was present at the sn-1 position, it accounted for over 50% of the fatty acids at position sn-3. The results indicate that the diacylglycerol acyltransferase (EC 2.3.1.20) may show a strong selectivity for gamma-linolenoyl-CoA and hence result in the efficient removal of this fatty acid from the acyl-CoA pool in vivo, leaving negligible substrate for utilization by the sn-glycerol 3-phosphate acyltransferase (EC 2.3.1.15).

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Awl, R. A., E. N. Frankel, and D. Weisleder. "Synthesis and characterization of triacylglycerols containing linoleate and linolenate." Lipids 24, no. 10 (October 1989): 866–72. http://dx.doi.org/10.1007/bf02535761.

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Awl, R. A., E. N. Frankel, and D. Weisleder. "Synthesis and characterization of triacylglycerols containing linoleate and linolenate." Lipids 25, no. 1 (January 1990): 72. http://dx.doi.org/10.1007/bf02562432.

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Thompson, Alison L., Megan Y. C. Lim-Fraser, Edward W. Kraegen, and Gregory J. Cooney. "Effects of individual fatty acids on glucose uptake and glycogen synthesis in soleus muscle in vitro." American Journal of Physiology-Endocrinology and Metabolism 279, no. 3 (September 1, 2000): E577—E584. http://dx.doi.org/10.1152/ajpendo.2000.279.3.e577.

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Soleus muscle strips from Wistar rats were preincubated with palmitate in vitro before the determination of insulin-mediated glucose metabolism in fatty acid-free medium. Palmitate decreased insulin-stimulated glycogen synthesis to 51% of control in a time- (0–6 h) and concentration-dependent (0–2 mM) manner. Basal and insulin-stimulated glucose transport/phosphorylation also decreased with time, but the decrease occurred after the effect on glycogen synthesis. Preincubation with 1 mM palmitate, oleate, linoleate, or linolenate for 4 h impaired glycogen synthesis stimulated with a submaximal physiological insulin concentration (300 μU/ml) to 50–60% of the control response, and this reduction was associated with impaired insulin-stimulated phosphorylation of protein kinase B (PKB). Preincubation with different fatty acids (all 1 mM for 4 h) had varying effects on insulin-stimulated glucose transport/phosphorylation, which was decreased by oleate and linoleate, whereas palmitate and linolenate had little effect. Across groups, the rates of glucose transport/phosphorylation correlated with the intramuscular long-chain acyl-CoA content. The similar effects of individual fatty acids on glycogen synthesis but different effects on insulin-stimulated glucose transport/phosphorylation provide evidence that lipids may interact with these two pathways via different mechanisms.

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More sources

Dissertations / Theses on the topic "Linoleate"

1

Belza, Krystian G. "The metabolism of [1-¹§4C] linoleate in linoleate deficient rats." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29292.pdf.

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2

Ma, Tiezheng. "Oxidation Kinetics of Methyl Linoleate and α-Linolenate in Bulk and Oil-in-water Emulsion Systems." Kyoto University, 2014. http://hdl.handle.net/2433/188751.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第18313号
農博第2038号
新制||農||1020(附属図書館)
学位論文||H26||N4820(農学部図書室)
31171
京都大学大学院農学研究科食品生物科学専攻
(主査)教授安達修二, 教授河田照雄, 教授保川清
学位規則第4条第1項該当

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Trotti, Domenic. "Linoleate deficiency in rats, measurement of carbon recycling from linoleate and a comparison with essential fatty acid deficiency." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0013/MQ40827.pdf.

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4

Le, Maux Solène. "β-lactoglobulin/linoleate complexes : binding properties and biological functions." Rennes, Agrocampus Ouest, 2013. http://www.theses.fr/2013NSARB238.

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Les interactions entre nutriments dans les produits alimentaires peuvent affecter leur bioaccessibilité. La β-lactoglobuline (βlg), protéine majeure du lactosérum, est connue pour lier des ligands hydrophobes tels que des acides gras (AG). Très sensible aux conditions industrielles, la βlg est souvent sous formes non natives dans les aliments transformés. Notre hypothèse est que les changements structuraux au niveau de la protéine modifient l'affinité pour les AG et par conséquent les propriétés biologiques des complexes AG/protéine. L'objectif était d'étudier l'interaction de la βlg bovine sous différentes structures (native, dimère covalent et nanoparticules) avec l’acide linoléique (LA) et l’acide linoléique conjugué (CLA), et l'impact de ces complexes sur leurs activités biologiques in vitro. Par fluorescence intrinsèque et calorimétrie de titration isotherme, nous avons montré que quel que soit l’état d'agrégation de la protéine, LA interagit avec la βlg au niveau de deux classes de sites. En augmentant le niveau d’agrégation de la βlg, la stœchiométrie des complexes LA/βlg augmente mais sans changement des constantes d'association. En présence de LA, la βlg native est plus sensible à la digestion gastrique in vitro en raison de l'augmentation du niveau de dénaturation/agrégation de la βlg. La quantification de l’absorption du LA dans une monocouche cellulaire imitant la barrière intestinale indique que son transport est ralenti en présence de βlg native ce que confirme la microscopie confocale. La cytotoxicité du LA pour les cellules Caco-2 a été réduite lorsque l’AG était lié à la βlg. Le CLA, qui est moins soluble dans l'eau que le LA, est plus cytotoxique lorsqu'il est complexé à la βlg que sous sa forme libre. Par conséquent, la βlg peut moduler le transport et la bioaccessibilité de l’AG en fonction de la solubilité de ce dernier
Food structure can have a profound influence on delivering health benefits. Bioaccessibility of nutrients can be affected by their interaction with food components. The dairy protein β-lactoglobulin (βlg) is known to bind hydrophobic ligands such as fatty acids (FA). However, this protein is highly sensitive to the process conditions used in the dairy industry. Therefore βlg is often present in non-native or aggregated form in processed food. This structural change may modify the protein affinity for FA and the biological properties of the FA/protein complexes. The aim of this thesis was to investigate the interaction of bovine βlg in different structural forms (native, covalent dimer and nanoparticles) with linoleate (C18:2, cis,cis-9,12-octadecadienoic acid) and conjugated linoleic acids (CLA, C18:2), and the impact of those complexes on their biological activity in vitro. Two different sets of binding sites were determined for the interaction between linoleate and βlg, regardless of its state of aggregation, using intrinsic fluorescence spectroscopy and isothermal titration calorimetry. By increasing the level of βlg aggregation, the linoleate/βlg stoichiometry increased but the association constants remained similar for both sets of binding sites. In the presence of linoleate, the native protein was more sensitive to gastric in vitro digestion, due to the increased level of denaturation/aggregation of βlg. Transport of linoleate in Caco-2 cells was decreased in presence of the native βlg as observed by confocal microscopy and a monolayer that mimics the intestinal barrier. Cytotoxicity of linoleate on Caco-2 cells was reduced when the FA was bound to βlg compared to free FA. CLA, which is less water soluble than linoleate, is more cytotoxic when complexed by βlg than in its free form. Therefore, it is proposed that βlg can act as a molecular carrier and alter the bioaccessibility of FA depending on their solubility

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Cazzolli, Rosanna St Vincents Campus UNSW. "The effects of linoleate on insulin action in skeletal muscle cells." Awarded by:University of New South Wales. St Vincents Campus, 2005. http://handle.unsw.edu.au/1959.4/22925.

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Emerging evidence suggests that an important mechanism for the negative feedback control of insulin signalling involves the inhibition of tyrosine phosphorylation of IRS-1 by its prior serine/threonine (ser/thr) phosphorylation. IRS-1 ser/thr phosphorylation has been linked to the dissociation of IRS-1 from the insulin receptor and PI3K, and its degradation via a proteasome-dependent pathway. Studies in animal models have shown that increases in plasma free fatty acids (FFAs) are associated with reduced IRS-1-signalling, and so it has been postulated that elevated FFA cause insulin resistance by activating pathways that negatively regulate insulin action, including hyper-phosphorylation of ser/thr residues in IRS-1. We have shown that in the case of linoleate-induced insulin resistance in L6 rat skeletal muscle cells, the inhibition of IRS-1-dependent signalling arises via effects on both the phosphorylation status and degradation of IRS-1, which are mediated, in part, by IKKb. In addition, the reduction of IRS-1 mRNA levels allude to transcriptional effects of linoleate treatment that also contribute to the observed reduction in the total levels of this protein. PtdOH, particularly dilinoleoyl PtdOH, was found to be significantly increased in linoleate treated L6 cells, and sufficient to induce at least some of the effects on insulin-signalling that are observed upon linoleate treatment. It is unlikely, however, that IKKb and PtdOH are components of the same inhibitory pathway, since inhibiting IKKb activity did not alleviate the effects of PtdOH on IRS-1 tyrosine (tyr) phosphorylation. Moreover, although an integral component of the mechanism by which linoleate induces insulin-resistance in L6 cells, it appears that restoring IRS-1 function in linoleate treated cells is not sufficient to reverse insulin resistance. Hence, we hypothesise that linoleate induces multiple inhibitory pathways in L6 cells, with at last two of these involving IKKb- and PtdOH-dependent inhibition of IRS-1 signalling, which act in parallel to reduce glucose disposal and cause insulin resistance in this model.

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6

Wang, Ting. "Monitoring a natural autoxidation process of methyl linoleate by using GC-MS." Scholarly Commons, 2003. https://scholarlycommons.pacific.edu/uop_etds/586.

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The methyl ester of an unsaturated fatty acid, methyllinoleate was reacted with oxygen in a pressurized system at a controlled temperature. A natural autoxidation of methyl linoleate was observed without the addition of an initiating reagent. This autoxidation process could be used to mimic the course of lipid peroxidation, which is the major cause ofradical damage to living cells. The technology of GC-MS was employed to monitor the autoxidation of methyllinoleate. Eight of the autoxidation products separated by GC column were identified by interpreting the corresponding EI ion mass spectra. The products from 9-alkoxy methyl linoleate radical were methyl octanate, 2,4-decadienal, nonanoic acid, 9-oxo-methyl ester, and its further oxidation product, nonanedioic acid, monomethyl ester. All of them formed through a pathway of beta-cleavage. The products from 13-alkoxy methyl linoleate radical were tridecanoic acid, 9, 11-diene-13-oxo-methyl ester, hex anal, and its further oxidation product, hexanoic acid. They were also formed through a mechanism of beta-cleavage. The fourth product from 13-alkoxy methyllinoleate radical was 13-keto-9, 11-octadecadienoic acid, methyl ester, which was obtained through a pathway of keto formation. Observation of their concentrations in the samples at different autoxidation periods revealed the time-course of formation of these products.

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Wang, Ting. "Monitoring a natural autoxidation process of methyl linoleate by using GC-MS : a thesis." Scholarly Commons, 2001. https://scholarlycommons.pacific.edu/uop_etds/586.

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The methyl ester of an unsaturated fatty acid, methyllinoleate was reacted with oxygen in a pressurized system at a controlled temperature. A natural autoxidation of methyl linoleate was observed without the addition of an initiating reagent. This autoxidation process could be used to mimic the course of lipid peroxidation, which is the major cause ofradical damage to living cells. The technology of GC-MS was employed to monitor the autoxidation of methyllinoleate. Eight of the autoxidation products separated by GC column were identified by interpreting the corresponding EI ion mass spectra. The products from 9-alkoxy methyl linoleate radical were methyl octanate, 2,4-decadienal, nonanoic acid, 9-oxo-methyl ester, and its further oxidation product, nonanedioic acid, monomethyl ester. All of them formed through a pathway of beta-cleavage. The products from 13-alkoxy methyl linoleate radical were tridecanoic acid, 9, 11-diene-13-oxo-methyl ester, hex anal, and its further oxidation product, hexanoic acid. They were also formed through a mechanism of beta-cleavage. The fourth product from 13-alkoxy methyllinoleate radical was 13-keto-9, 11-octadecadienoic acid, methyl ester, which was obtained through a pathway of keto formation. Observation of their concentrations in the samples at different autoxidation periods revealed the time-course of formation of these products.

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8

Scholten, Matthew John. "Enzymatic and chemical modification of fatty acid methyl esters: enzymatic catalysis of methyl linoleate using soybean lipoxygenase and chemical catalysis of methyl oleate Using Hypobromination." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/735.

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Vegetable oils are a cheap and abundant chemical feedstock which can be readily broken down into fatty acid methyl esters (FAMEs) by transesterification using methanol and a base catalyst. These FAMEs contain reactive unsaturated double bonds which can be targeted for modification. In this study, enzymatic and chemical modifications of the unsaturated double bonds of FAMEs are explored with the goal of producing higher value products. Specifically the enzymatic modification of methyl linoleate using soybean lipoxygenase and the chemical modification of methyl oleate using hypobromantion are studied.

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9

Hoffmann, Inga. "Discovery of Novel Fatty Acid Dioxygenases and Cytochromes P450 : Mechanisms of Oxylipin Biosynthesis in Pathogenic Fungi." Doctoral thesis, Uppsala universitet, Institutionen för farmaceutisk biovetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-206199.

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Dioxygenase-cytochrome P450 (DOX-CYP) fusion enzymes are present in diverse human and plant pathogenic fungi. They oxygenate fatty acids to lipid mediators which have regulatory functions in fungal development and toxin production. These enzymes catalyze the formation of fatty acid hydroperoxides which are subsequently converted by the P450 activities or reduced to the corresponding alcohols. The N-terminal DOX domains show catalytic and structural homology to mammalian cyclooxygenases, which belong to the most thoroughly studied human enzymes. 7,8-Linoleate diol synthase (LDS) of the plant pathogenic fungus Gaeumannomyces graminis was the first characterized member of the DOX-CYP fusion enzyme family. It catalyzes the conversion of linoleic acid to 8R-hydroperoxylinoleic acid (HPODE) and subsequently to 7S,8S-dihydroxylinoleic acid by its DOX and P450 domains, respectively. By now, several enzymes with homology to 7,8-LDS have been identified in important fungi, e.g., psi factor-producing oxygenase (ppo)A, ppoB, and ppoC, of Aspergillus nidulans and A. fumigatus. By cloning and recombinant expression, ppoA of A. fumigatus was identified as 5,8-LDS. Partial expression of the 8R-DOX domains of 5,8-LDS of A. fumigatus and 7,8-LDS of G. graminis yielded active protein which demonstrates that the DOX activities of LDS are independent of their P450 domains. The latter domains were shown to contain a conserved motif with catalytically important amide residues. As judged by site-directed mutagenesis studies, 5,8- and 7,8-LDS seem to facilitate heterolytic cleavage of the oxygen-oxygen bond of 8R-HPODE by aid of a glutamine and an asparagine residue, respectively. Cloning and expression of putative DOX-CYP fusion proteins of A. terreus and Fusarium oxysporum led to the discovery of novel enzyme activities, e.g., linoleate 9S-DOX and two allene oxide synthases (AOS), specific for 9R- and 9S-HPODE, respectively. The fungal AOS are present in the P450 domains of two DOX-CYP fusion enzymes and show higher sequence homology to LDS than to plant AOS and constitute therefore a novel class of AOS. In summary, this thesis describes the discovery of novel fatty acid oxygenases of human and plant pathogenic fungi and the characterization of their reaction mechanisms.

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Garscha, Ulrike. "Catalytic and Structural Properties of Heme-containing Fatty Acid Dioxygenases : Similarities of Fungal Dioxygenases and Cyclooxygenases." Doctoral thesis, Uppsala universitet, Institutionen för farmaceutisk biovetenskap, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-108770.

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7,8-Linoleate diol synthase (7,8-LDS) of the take-all pathogen of wheat, Gaeumannomyces graminis, converts linoleic acid to 8R-hydroperoxyoctadecadienoic acid (8-HPODE) by 8-dioxygenase activity (8-DOX), and further isomerizes the hydroperoxide to 7S,8S-dihydroxyoctadecadienoic acid (7,8-DiHODE) by hydroperoxide isomerase activity. Sequence alignment showed homology to prostaglandin H synthase (PGHS), and both enzymes share structural and catalytic properties. The 8-DOX of 7,8-LDS was successfully expressed in Pichia pastoris and in insect cells (Sf21). Site-directed mutagenesis confirmed His379 as the proximal heme ligand and Tyr376 as a residue, which forms a tyrosyl radical and initiates catalysis. Furthermore, mutagenesis suggested His203 could be the proposed distal histidine, and Tyr329 of catalytic relevance for substrate positioning at the active site. Aspergilli are ubiquitous environmental fungi. Some species, in particular Aspergillus fumigatus, are responsible for invasive aspergillosis, which is a life-threatening disease for immunocompromised patients. A. fumigatus and A. nidulans metabolized linoleic acid to 8R-HPODE, 10R-hydroperoxyoctadecadienoic acid (10R-HPODE), 5S,8R-dihydroxyoctadecadienoic acid, and 8R,11S-dihydroxyoctadecadienoic acid. When the genomes of certain Aspergilli strains were published, several species showed at least three homologous genes (ppoA, ppoB, ppoC- psi producing oxygenases) to 7,8-LDS and PGHS. Gene deletion identified PpoA as an enzyme with 8-DOX and 5,8-hydroperoxide isomerase activities, designated 5,8-LDS in homology to 7,8-LDS. In the same way, PpoC was identified as a 10-dioxygenase (10-DOX), which converts linoleic acid to 10R-HPODE. 10-DOX differs from LDS, since it dioxygenates linoleic acid at C-10, after hydrogen abstraction at C-8 and double bond migration. 10-DOX was cloned and expressed in insect cells. Leu384 and Val388 were found to be critical for dioxygenation at C-10. Mutation to the homologous residues of 5,8- and 7,8-LDS (Leu384Val, Val388Leu) increased oxygen insertion at C-8. LDS and 10-DOX are fusion proteins with a dioxygenase and a hydroperoxide isomerase (cytochrome P450) domain with a cysteine heme ligand. The P450 domain of 10-DOX lacked the crucial cysteine heme ligand and was without hydroperoxide isomerase activity. LDSs and 10-DOX are newly characterized heme containing fungal dioxygenases, with homology to PGHS of vertebrates. Their metabolites regulate reproduction, development, and act as signal molecules with the host after pathogen attack.

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Books on the topic "Linoleate"

1

Belza, Krystian G. The metabolism of [1-p1sp4sC] linoleate in linoleate deficient rats. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.

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Anderson, Matthew James. The utilisation and accumulation of linoleate. Ottawa: National Library of Canada, 1995.

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Linoleate deficiency in rats: Measurement of carbon recycling from linoleate and a comparison with essential fatty acid deficiency. Ottawa: National Library of Canada, 1998.

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Kahl, Jennifer Lynn. The effect of water and cobalt on methyl linoleate autoxidation. 1986.

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Decker, Eric Andrew. Catalysis of linoleate oxidation by heme and non-heme soluble chicken muscle proteins. 1985.

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Chen, Hao. The inhibitory effect of water on the decomposition of methyl linoleate hydroperoxides in a model system using NMR spectroscopy. 1989.

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Higdon, Jane V. The effect of oleate, linoleate, and EPA/DHA supplementation of postmenopausal women on in vivo lipid peroxidation and LDL susceptibility to ex vivo oxidation. 1999.

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Su, Chao. Characterization of 2 Novel Fatty Acid Dioxygenases: Linoleate Diol Synthase and Manganese Lipoxygenase (Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy, 209). Uppsala Universitet, 1999.

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Book chapters on the topic "Linoleate"

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Bährle-Rapp, Marina. "Stearyl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 531. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_10061.

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Bährle-Rapp, Marina. "Ethyl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 193. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_3773.

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Bährle-Rapp, Marina. "Glyceryl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 228. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_4366.

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Bährle-Rapp, Marina. "Glyceryl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 228. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_4367.

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Bährle-Rapp, Marina. "Isopropyl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 288. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5397.

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Gooch, Jan W. "Calcium Linoleate." In Encyclopedic Dictionary of Polymers, 110. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_1827.

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Bährle-Rapp, Marina. "Potassium Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 444. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_8322.

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Bährle-Rapp, Marina. "Sodium Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 513. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_9611.

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Bährle-Rapp, Marina. "Retinyl Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 475. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_8886.

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Bährle-Rapp, Marina. "Lanolin Linoleate." In Springer Lexikon Kosmetik und Körperpflege, 311. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5811.

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Conference papers on the topic "Linoleate"

1

Yusri, Silvya, Hery Sutanto, and Mohammad Nasikin. "The optimization of pyrogallol and methyl linoleate coupling reaction." In THE 8TH ANNUAL BASIC SCIENCE INTERNATIONAL CONFERENCE: Coverage of Basic Sciences toward the World’s Sustainability Challanges. Author(s), 2018. http://dx.doi.org/10.1063/1.5062723.

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Wang, Chun-E., Rui-Kai Wang, Jin-Ying Dai, and Tuan-Jie Zhao. "Phylogeny and expression profile analyses of oleate- and linoleate-desaturase genes in soybean." In 2011 4th International Conference on Biomedical Engineering and Informatics (BMEI). IEEE, 2011. http://dx.doi.org/10.1109/bmei.2011.6098571.

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Anderson, Kevin R., Christopher McNamara, and Ariel Gatti. "Analysis of a Multi-Cascade Methyl Linoleate / SCO2 / Transcritical CO2 / R-410A Refrigeration Cycle for Use in High Temperature High Pressure Environments." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65547.

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This paper presents the results of an analysis of a hybrid cascaded Methyl Linoleate / Supercritical (SCO2) / Transcritical CO2 / R-410A cycle for extreme environment refrigeration applications. The particular application of this cascaded CO2 refrigeration cycle stems from a space exploration application of a Venus lander mission. The payload of the Venus lander is subject an extremely harsh environment, i.e. the objective is to maintain a 1 cubic meter payload cavity at 35 °C, with dissipation of 500 W to an environmental temperature of 465 °C. Complicating the situation is the Venus local atmosphere is 9 MPa, and the atmosphere is mainly comprised of CO2 (95.5% by volume, 3.5% N2 by volume). Because this temperature is so high, to stay under the saturation dome we need some fairly exotic fluids to do a normal vapor compression system. Some of the only fluids with critical points allowing for this particular application are sulfuric acid and Fatty Acid Methyl Ester (FAME) type bio-diesels such as Methyl Linoleate (MLL). The actual heat rejection process and throttling processes are the primary challenges of this research topic. Results of a COP comparison and a lift curve are carried out in order to determine efficiency and guide feasibility of realizing the actual hardware to be used in the cycle.

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Yusri, Silvya, Hery Sutanto, and Mohammad Nasikin. "Size-Selective Adsorption in Separation of Products from Pyrogallol and Methyl Linoleate Oxidative Coupling Reaction." In 2018 2nd International Conference on Green Energy and Applications (ICGEA). IEEE, 2018. http://dx.doi.org/10.1109/icgea.2018.8356316.

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Heiremans, J., M. Claeys, and A. G. Herman. "DETERMINATION OF CHOLESTERYL HYDROXYOCTADBCADIENOATES IN VASCULAR TISSUE BY HPLC AND ITS RELEVANCE TO ATHEROSCLEROSIS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643084.

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Accumulation of lipids in the intimal arterial layer, and of cholesterol esters in particular, has been recognised as an early and prominent phenomenon in atherogenesis. Several attempts have been made to link putative peroxidation of these lipids in vivo to causal or deteriorating etiological determinants of plaque formation. The occurrence in advanced human atheromata of oxidized derivatives of cholesteryl linoleate -a major polyunsaturated cholesterol ester species in plasma and vessel wall - has been described by Brooks et al. (Atherosclerosis, 1970,13,223) and a positive correlation between the amount of cholesteryl hydroxyoctadecadienoates (CHODES) and the stage of the lesion has also been reported. In addition Funk and Powell (J. Biol. Chem., 1985,260,7481) have found hydroxyoctadecadienoic acids in normal aorta of different species, wich were strikingly increased after alkaline hydrolysis of total lipids, and this in contrast with the arachidonic acid analogs. The aim of this study was to develop a sensitive and practical method for specific assay of CHODES, without resorting to laborious saponification and derivatisation procedures required for gas chromatographic analysis, which could moreover augment the risk for artefacts.Dog thoracal aorta was homogenised and lipids were extracted using the Folch method with CHCl3/CH30H;2/l containing 0.05mM butylated hydroxytoluene. Fractionation of CHODES from neutral lipids was carried out by thin-layer chromatography. For detection and quantification a high-performance liquid chromatography (HPI/2) assay method was developed, with UV monitoring at 232nm , a wavelength characteristic for conjugated dienes with vicinal hydroxyl function. Reference compounds and the internal standard for HPLC analysis were synthesized from linoleic acid and 10,13,16-docosatrienoic acid, respectively, by preparation of hydroxy fatty acids with soybean lipoxygenase and subsequent esterification to cholesterol esters with pancreas cholesterol esterase. Confirmation of the structural identity was obtained by mass spectrometry. Artefactual formation of CHODES ex vivo was investigated by subjecting radiolabeled cholesteryl linoleate through the analysis procedure. This method allows the specific detection of CHODES in non-atherosclerotic arteries which was hitherto only reported for human advanced atherosclerotic lesions and is proposed as a sensitive and specific probe for prospective survey of lipid peroxidation in atherosclerotic blood vessels.

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Wang, Weijing, and Matthew A. Oehlschlaeger. "The Shock Tube Autoignition of Biodiesels and Biodiesel Components." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17456.

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The autoignition of fatty-acid methyl ester biodiesels and methyl ester biodiesel components was studied in gas-phase shock tube experiments. Ignition delay times for two reference methyl ester biodiesel fuels, derived from methanol-based transesterification of soybean oil and animal fats, and four primary constituents of all methyl ester biodiesels, methyl palmitate, methyl stearate, methyl oleate, and methyl linoleate, were measured behind reflected shock waves for fuel/air mixtures at temperatures ranging from 900 to 1350 K and at pressures around 10 and 20 atm. Ignition delay times were determined by monitoring pressure and chemiluminescence from electronically-excited OH radicals around 310 nm. The results show similarity in ignition delay times for all methyl ester fuels considered, irrespective of the variations in organic structure, at the high-temperature conditions studied and also similarity in high-temperature ignition delay times for methyl esters and n-alkanes.

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Anderson, Kevin R., and Trevor Steele. "Analysis of a FAME/MLL Screw Multi-Stage Compressor for High Temperature, High Pressure Vapor Compression Refrigeration Cycle." In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20002.

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Abstract This paper presents the analysis and design of a compressor for application to a Fatty Acid Methyl Ester (FAME) Methyl Linoleate (MLL) bio-refrigerant cascade working cycle. This working fluid is being used in the topping cycle of an active electronics payload cooling system design to operate at elevated temperatures and pressures such as those witnessed by a Venus lander. The twin-screw, three-stage compressor operates at escalated temperatures of approximately 520 °C (960 °F). The total compressor power of 143.4 W is shared as 43.5 W, 47.7 W, and 53.3 W over stages 1, 2, and 3, respectively. The screw compressor is baselined with a D = 1 inch diameter rotor and an L/D (stroke/bore) ratio of L/D = 2 per stage. The compression ratio corresponds to a volume ratio of 6.5. The swept volume for a 4+6 rotor configuration is estimated to be 1.13 CFM at 2000 RPM with an asymmetric profile and no leakage. The volumetric efficiency of the compressor is estimated to be on the order of 80% due to the higher molecular weight of the FAME/MLL working fluid. The SCORG turbomachinery software is used to verify the thermodynamics analysis and affords a volumetric displacement of 0.025 L/rev at 2000 RPM and 80% adiabatic efficiency.

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Miotti, Rodney, Elisa Zaparoli Ramos, Adriano Aguiar Mendes, and Daniela Battaglia Hirata. "OTIMIZAÇÃO DA SÍNTESE DE LINOLEATO DE ETILA UTILIZANDO A LIPASE PRODUZIDA DE Geotrichum candidum, IMOBILIZADA EM UM SUPORTE DE BAIXO CUSTO." In Simpósio Nacional de Bioprocessos e Simpósio de Hidrólise Enzimática de Biomassa. Campinas - SP, Brazil: Galoá, 2015. http://dx.doi.org/10.17648/sinaferm-2015-31765.

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