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为了探究脂肪酸饱和度对其植物甾醇酯生物可给率的影响，采用体外模拟消化静态模型，系统研究了油酸豆甾醇酯、亚油酸豆甾醇酯和亚麻酸豆甾醇酯的体外模拟消化规律。结果表明：体外模拟消化结束后（120 min),亚油酸豆甾醇酯游离脂肪酸（FFA）释放率最高，为78.51%，其次是亚麻酸豆甾醇酯，为74.21%，油酸豆甾醇酯FFA释放率最低，为69.15%；3种豆甾醇酯的水解速率由大到小为亚麻酸豆甾醇酯>亚油酸豆甾醇酯>油酸豆甾醇酯；3种豆甾醇酯的水解度由大到小为亚油酸豆甾醇酯>亚麻酸豆甾醇酯>油酸豆甾醇酯；油酸豆甾醇酯、亚油酸豆甾醇酯和亚麻酸豆甾醇酯生物可给率分别为14.01%、11.11%和10.19%，总体差异较小。综上，豆甾醇酯中结合态的脂肪酸（相同碳链长度）饱和度影响其水解速率，但对豆甾醇酯生物可给率影响较小。 In order to investigate the effect of fatty acid saturation on the bioaccessibility of phytosterol ester, a static model of in vitro digestion was used to study the digestion characteristics of stigmasterol oleate, stigmasterol linoleate and stigmasterol linolenate. The results showed that after the simulated digestion in vitro (120 min), the free fatty acid (FFA) release rate of stigmasterol linoleate was the highest with 78.51%, followed by stigmasterol linolenate with 74.21%, and that of stigmasterol oleate was the lowest with 69.15%. The hydrolysis rates of the three stigmasterol esters decreased in the order: stigmasterol linolenate > stigmasterol linoleate> stigmasterol oleate. The degree of hydrolysis of stigmasterol esters decreased in the order: stigmasterol linoleate > stigmasterol linolenate > stigmasterol oleate. The bioaccessibilities of stigmasterol oleate, stigmasterol linoleate and stigmasterol linolenate were 14.01%, 11.11% and 10.19% respectively, and the overall difference was small. In conclusion, the degree of saturation of bound fatty acids (same carbon chain length) in stigmasterol esters affects the hydrolysis rate, but has little effect on the bioaccessibility of stigmasterol esters.

Breast cancer (BC) is the most common malignancy in women worldwide. While the main systemic treatment option is anthracycline-containing chemotherapy, chemoresistance continues to be an obstacle to patient survival. Carnitine palmitoyltransferase 1C (CPT1C) has been described as a poor-prognosis marker for several tumour types, as it favours tumour growth and hinders cells from entering senescence. At the molecular level, CPT1C has been associated with lipid metabolism regulation and important lipidome changes. Since plasma membrane (PM) rigidity has been associated with reduced drug uptake, we explored whether CPT1C expression could be involved in PM remodelling and drug chemoresistance. Liquid chromatography-high resolution mass spectrometry (LC-HRMS) lipid analysis of PM-enriched fractions of MDA-MB-231 BC cells showed that CPT1C silencing increased PM phospholipid saturation, suggesting a rise in PM rigidity. Moreover, CPT1C silencing increased cell survival against doxorubicin (DOX) treatment in different BC cells due to reduced drug uptake. These findings, further complemented by ROC plotter analysis correlating lower CPT1C expression with a lower pathological complete response to anthracyclines in patients with more aggressive types of BC, suggest CPT1C as a novel predictive biomarker for BC chemotherapy. [ABSTRACT FROM AUTHOR]

Lipid metabolism is essential for all major cell functions and has recently gained increasing attention in research and health studies. However, mathematical modeling by means of classical approaches such as stoichiometric networks and ordinary differential equation systems has not yet provided satisfactory insights, due to the complexity of lipid metabolism characterized by many different species with only slight differences and by promiscuous multifunctional enzymes.Here, we present a object-oriented stochastic model approach as a way to cope with the complex lipid metabolic network. While all lipid species are treated objects in the model, they can be modified by the respective converting reactions based on reaction rules, a hybrid method that integrates benefits of agent-based and classical stochastic simulation. This approach allows to follow the dynamics of all lipid species with different fatty acids, different degrees of saturation and different headgroups over time and to analyze the effect of parameter changes, potential mutations in the catalyzing enzymes or provision of different precursors. Applied to yeast metabolism during one cell cycle period, we could analyze the distribution of all lipids to the various membranes in time-dependent manner.The presented approach allows to efficiently treat the complexity of cellular lipid metabolism and to derive conclusions on the time- and location-dependent distributions of lipid species and their properties such as saturation. It is widely applicable, easily extendable and will provide further insights in healthy and diseased states of cell metabolism.

Callisto, containing the active ingredient mesotrione (2-[4-methylsulfonyl-2-nitrobenzoyl]1,3-cyclohenanedione), is a selective herbicide that controls weeds in corn crops and is a potential environmental contaminant. The objective of this work was to evaluate enzymatic and structural changes in Pantoea ananatis, a strain isolated from water, in response to exposure to this herbicide. Despite degradation of mesotrione, probably due a glutathione-S-transferase (GST) pathway in Pantoea ananatis, this herbicide induced oxidative stress by increasing hydrogen peroxide production. Thiol fragments, eventually produced after mesotrione degradation, could be involved in increased GST activity. Nevertheless, there was no peroxidation damage related to this production, as malondialdehyde (MDA) synthesis, which is due to lipid peroxidation, was highest in the controls, followed by the mesotrione- and Callisto-treated cultures at log growth phase. Therefore, P. ananatis can tolerate and grow in the presence of the herbicide, probably due an efficient control of oxidative stress by a polymorphic catalase system. MDA rates depend on lipid saturation due to a pattern change to a higher level of saturation. These changes are likely related to the formation of GST-mesotrione conjugates and mesotrione degradation-specific metabolites and to the presence of cytotoxic adjuvants. These features may shift lipid membrane saturation, possibly providing a protective effect to bacteria through an increase in membrane impermeability. This response system in P. ananatis provides a novel model for bacterial herbicide tolerance and adaptation in the environment. [ABSTRACT FROM AUTHOR]

Summary: In this project, we hypothesize that cotton (Gossypium hirsutum) leaf temperature and the responses of leaf photosynthesis to temperature will change as the leaves expand and that differences between young and mature leaves will be associated with the proportion of saturated fatty acids in thylakoid and other membrane lipids. To that end, we studied main stem leaves obtained from plants growing in a temperature controlled greenhouse and at different times in the field season. We found that young leaves (∼5d old) had higher mid day temperatures, lower stomatal conductance and higher thermal optima as measured by Φ PSII temperature curves than did more mature leaves (∼13d old). Young leaves also had significant differences in fatty acid saturation with the warmer, young leaves having a higher proportion of palmitic acid (16:0) and lower linoleic acid (18:3) in total lipid extracts and higher 16:0 and lower palmitoleic acid (16:1) in the chloroplast membrane phosphoglycerides, digalactosyldiacylglycerol (in the greenhouse) and phosphatidylglycerol when compared with cooler, more mature leaves. Later in the growing season, leaf temperature, stomatal conductance and Φ PSII temperature curves for young and more mature leaves were similar and the proportion of 16:0 fatty acids decreased and 16:1 increased in phosphatidylglycerol. We conclude that changes in temperature as cotton leaves expand leads to alterations in the fatty acid composition of thylakoid and other membranes and, consequently, influence photosynthesis/temperature responses. [Copyright &y& Elsevier]

The fatty acid ( FA) profiles of two strains of the yeasts Wickerhamomyces anomalus and Blastobotrys ( Arxula) adeninivorans at cultivation temperatures from 15 to 30 °C were characterized. Besides the common even-numbered C16 and C18 FAs, substantial proportions of the uneven-numbered C17:1 were found in both species. C18:3(n-3) (alpha linolenic acid) made up to 3% of the total FAs in all strains. Considerable strain differences occurred, with regard to both the presence of single FAs and parameters like the double binding index ( DBI) and C16:C18 ratio. W. anomalus J121 formed C18:1(n-5) (up to 10.9% of the total FAs) but no C18:1(n-7), whereas in W. anomalus VKM160, no C18:1(n-5) was found but up to 14.6% C18:1(n-7). Similarly, B. adeninivorans CBS 8244 formed exclusively C18:1(n-7) (maximum 9%) and CBS 7377 C18:1(n-5) (maximum 12.6%). W. anomalus J121 had the lowest DBI (0.72) at 15 °C and the highest (0.92) at 20 °C, at which point the values decreased with increasing temperatures. In W. anomalus VKM160 and both B. adeninivorans strains, DBI was highest at 15 °C and decreased with increasing temperature. In J121, the C16:C18 ratio was highest at 15 °C, decreasing at higher temperatures, whereas in the other strains, the opposite trend was observed. [ABSTRACT FROM AUTHOR]

The possibility to use membrane-lipid measurements to screen barley genotypes for salt resistance was studied. The results showed that wild barley ( Hordeum maritimum) displayed a typical halophytic response as compared to cultivated barley ( Hordeum vulgare L. cv. Manel). Growth, tissue hydration, and photosynthetic activity were less affected by salinity in H. maritimum than in H. vulgare. The induced effects of long-term NaCl treatment were reflected in root membrane lipids that remained relatively unchanged in wild barley, whilst they were significantly diminished with increasing salinity in H. vulgare. The levels of membrane-lipid peroxidation and electrolyte leakage were changed only at high salt concentrations in H. maritimum whereas those of H. vulgare were considerably increased by lower salinity levels as a result of oxidative damage. These findings indicate that maintained membrane integrity (in H. Maritimum) may be considered a possible trait for salt resistance. However, membrane fluidity in H. vulgare was more increased than in H. maritimum. Thus, the unsaturated-to-saturated fatty acid ratio (UFAs : SFAs) and the double-bond index (DBI), significantly increased in response to salt stress in cultivated barley while it did not change in H. maritimum. The changes in lipid unsaturation were predominantly due to increases in linolenic (C18:3), linoleic (C18:2), and oleic (C18:1) acids and decreases in stearic acid (C18:0). These results suggest that, in spite of being important for maintenance of membrane fluidity, the ability to increase unsaturation is not a determinant factor for salt resistance in barley species. [ABSTRACT FROM AUTHOR]

Saturated and unsaturated fatty acid supplements (FS) were evaluated for effects on feed intake, meal patterns, and chewing behavior. Eight ruminally and duodenally cannulated cows were used in a replicated 4 x 4 Latin square design experiment with 21-d periods. Treatments were control and a linear substitution of 2.5% fatty acids from supplemented saturated FS (SAT; prilled, hydrogenated free fatty acids) for partially unsaturated FS (UNS; calcium soaps of long-chain fatty acids). All rations contained identical forage and concentrate components including 37.2% forage and 13.5% cottonseed. Dry matter intake for SAT was not different from control, whereas increasing unsaturated FS linearly decreased dry matter intake by 3.2 kg. Wet weight of ruminal digesta decreased linearly up to 11.3 kg (13%) with increasing unsaturated FS. Adding supplementary fatty acids did not change meal number, meal length, or time between meals compared with control, but increasing unsaturated FS decreased meal size 0.22 kg (9%) within FS. The SAT treatment increased time spent ruminating by 56 (10%) and 42 (7%) min/d compared with control and UNS, respectively. Increasing saturated FS did not affect frequency of rumination bouts or interval between bouts, but increased rumination bout length by 5.6 min. Water intake was not affected by treatment, but increasing saturated FS linearly decreased the number of drinking bouts per day by up to 2.9 bouts (23%). Increased unsaturated fatty acid flow to the duodenum decreased feed intake by decreasing meal size, and increased saturated fatty acid flow to the duodenum increased rumination time per day by increasing rumination bout length. [ABSTRACT FROM AUTHOR]

Studies with teleost larvae have reported poor performance associated with quantitative lipid imbalances in the diet. The present study examined the effect of dietary protein:neutral lipid ratio on fatty acid (FA) absorption efficiency and metabolism in larval Senegalese sole. In addition, the effect of lipid class (triolein (TRI) and l-3-phosphatidylcholine-1,2-di-oleoyl (PC)), carbon number and degree of saturation of the labelled NEFA, stearic acid (SA), oleic acid (OA) and DHA) was tested. FA absorption was determined by tube feeding [1-14C]-labelled lipids and NEFA after a single meal of either non-enriched Artemia (NEA) or Artemia enriched on a soyabean oil emulsion (EA), or after feeding these diets over an extended period of time (18 d). The tested dietary protein:lipid ratios had no short-term influence but long-term feeding of a diet higher in neutral lipid (EA) increased lipid accumulation within the gut epithelium and resulted in lower FA absorption (higher label evacuation and lower retention of dietary FA), which may partially explain the trend for lower growth observed with this diet. The lipids and NEFA, showed different digestive and metabolic properties, independent of feeding regime. FA absorption increased with unsaturation, being lowest for SA, followed by OA, and highest for DHA. In addition, sole larvae had a lower capacity to digest and absorb FA esterified to TRI, compared with PC, with the order of decreasing absorption being NEFA>PC???TRI. Moreover, larvae appeared to discriminate between the source of OA, as this FA in the free form or esterified to PC was catabolised less than TRI. [ABSTRACT FROM PUBLISHER]

The white-tailed prairie dog is a spontaneous hibernator which commences deep torpor bouts during early fall while the black-tailed prairie dog is a facultative hibernator that will only enter shallow torpor when stressed by cold and food deprivation. Plant oils rich in polyunsaturated fatty acids (PUFAs) enhance the duration and depth of mammalian torpor. Thus, we tested the hypothesis that black-tailed prairie dogs sampled in the field have less PUFAs in their diets and that the enhancement of torpor bouts by this species on a diet higher in PUFA is less profound than that by white-tailed prairie dogs. Individuals of both species fed a high PUFA diet: (1) entered torpor earlier, (2) had lower torpor body temperatures and (3) had longer bouts of torpor, compared to those on a low PUFA diet. However, the magnitude of this change was similar for both species. Additionally, the PUFA compositions of white adipose tissue (WAT) samples taken from individuals in the field were identical, indicating that diet PUFA contents for these two species were also equivalent. Therefore, while high PUFA diets can enhance hibernation by these species, it does not appear to explain the differences between spontaneous and facultative strategies. The rate of lipid peroxidation during torpor, however, was significantly higher in the WAT from white-tailed prairie dogs. Ancestral prairie dog species are spontaneous hibernators. Natural selection may have favored shallow, facultative hibernation with lower lipid peroxidation rates in the black-tailed prairie dogs as they radiated from the Rocky Mountains into the Great Plains. [ABSTRACT FROM AUTHOR]

Carotenoids are lipophilic pigments with polyene skeletons, which possess great benefits to human health. In this study, medium-chain triglyceride (MCT) and four long-chain triglycerides (LCTs), namely, soybean oil, sunflower seed oil, palm oil, and cottonseed oil, were applied as carriers to enrich carotenoids from Lycium barbarum L. by the freeze–thaw method. The fatty acid composition, thermal properties, and rheological properties of the carotenoid-enriched oils were determined. The carotenoid retention ratio (CRR) and peroxide value (POV) of the prepared oils were assessed during 56 days of storage. Kinetic analysis was conducted for CRR; meanwhile, a multivariate quadratic regression model was implemented to explain the POV changes. Results showed that the CRR of carotenoid-enriched oils decreased gradually following first-order kinetics. The CRR of MCT with low POV generation rate was significantly (p ＜0.05) lower than that of LCTs. Long-chain oils were beneficial for carotenoids stability. The carotenoid-enriched cottonseed oil (CCO) performed the best at 45 °C for 56 days, given the low monounsaturated fatty acids and slow POV generation rate. Thus, oils' chain length and fatty acid saturation would influence delivery material and delivery carrier stability, LCT with high saturation would be an ideal delivery system for carotenoids. • Carotenoid from Goji berry was enriched into MCT and four LCTs by freeze-thaw method. • Carotenoid retention ratio in MCT was significantly (p ＜0.05) lower than that in LCT. • Carotenoid retention in cottonseed oil was the highest after 56 days storage at 45 °C. • LCT with high saturation would be an ideal delivery system for carotenoids. [ABSTRACT FROM AUTHOR]

Exposure of barley (Hordeum vulgare L. cv. Himalaya) aleurone layers to 40 °C for a period of 3 h results in the selective suppression of the synthesis and secretion of hydrolytic enzymes; other normal cellular protein synthesis continues during heat shock. This suppression is correlated with secretory protein mRNA destabilization and the dissociation of stacked ER lamellae during heat shock (Belanger et al. 1986, Proceedings of the National Academy of Sciences USA 83, pp. 1354-1358). In this report we examined the effect of exposure to extended periods of heat shock. If exposure to 40°C was continued for a period of 18 h, the synthesis of α-amylase, the predominant secreted hydrolase, resumed. This was accompanied by increased α-amylase mRNA levels and the reformation of ER lamellae. Though initial exposure (3 h) to 40°C reduced protein secretion to ≈10% of that observed in aleurone cells maintained at 25°C, exposure for prolonged periods (16-20 h) permitted the resumption of protein secretion to ≈66 % of non-heat-shocked control levels. The resumption of normal secretory protein synthesis during prolonged exposure to 40°C was correlated with an increase in the incorporation of [14C]glycerol into phosphatidylcholine and an increase in the ratio of saturated to unsaturated fatty acids in lipids isolated from ER membrane preparations. Increased fatty acid saturation has been demonstrated to enhance thermostability in biological membranes, and such changes in membrane composition may be important to the recovery of secretory protein synthesis at the ER. [ABSTRACT FROM AUTHOR]

Phenotypic and metabolic heterogeneity within tumors is a major barrier to effective cancer therapy. How metabolism is implicated in specific phenotypes and whether lineage-restricted mechanisms control key metabolic vulnerabilities remain poorly understood. In melanoma, downregulation of the lineage addiction oncogene microphthalmia-associated transcription factor (MITF) is a hallmark of the proliferative-to-invasive phenotype switch, although how MITF promotes proliferation and suppresses invasion is poorly defined. Here, we show that MITF is a lineage-restricted activator of the key lipogenic enzyme stearoyl-CoA desaturase (SCD) and that SCD is required for MITFHigh melanoma cell proliferation. By contrast MITFLow cells are insensitive to SCD inhibition. Significantly, the MITF-SCD axis suppresses metastasis, inflammatory signaling, and an ATF4-mediated feedback loop that maintains de-differentiation. Our results reveal that MITF is a lineage-specific regulator of metabolic reprogramming, whereby fatty acid composition is a driver of melanoma phenotype switching, and highlight that cell phenotype dictates the response to drugs targeting lipid metabolism. • MITF is a lineage-specific regulator of the fatty acid desaturase SCD • MITFHigh but not MITFLow melanoma cells are sensitive to SCD inhibition • Low SCD triggers inflammation to impose and stabilize melanoma de-differentiation • Low SCD activity drives invasion and metastatic dissemination Vivas-Garcia et al. reveal that in melanoma, expression of the long-chain fatty acid desaturase SCD is controlled by the lineage-addiction oncogene MITF. The MITF-SCD axis suppresses stress and inflammatory signaling and inhibits invasion and metastatic dissemination, whereas low SCD activity imposes and stabilizes an MITFLow de-differentiated, invasive phenotype. [ABSTRACT FROM AUTHOR]

Summary Lipid droplets, which store triglycerides and cholesterol esters, are a prominent feature of clear cell renal cell carcinoma (ccRCC). Although their presence in ccRCC is critical for sustained tumorigenesis, their contribution to lipid homeostasis and tumor cell viability is incompletely understood. Here we show that disrupting triglyceride synthesis compromises the growth of both ccRCC tumors and ccRCC cells exposed to tumor-like conditions. Functionally, hypoxia leads to increased fatty acid saturation through inhibition of the oxygen-dependent stearoyl-CoA desaturase (SCD) enzyme. Triglycerides counter a toxic buildup of saturated lipids, primarily by releasing the unsaturated fatty acid oleate (the principal product of SCD activity) from lipid droplets into phospholipid pools. Disrupting this process derails lipid homeostasis, causing overproduction of toxic saturated ceramides and acyl-carnitines as well as activation of the NF-κB transcription factor. Our work demonstrates that triglycerides promote homeostasis by “buffering” specific fatty acids. Graphical Abstract Highlights • Hypoxia influences the FA composition of TGs more than other lipid classes • TGs maintain the cell’s FA saturation index by active oleate exchange • Release of TG-resident oleate during hypoxia prevents production of toxic lipids • Disrupting TG synthesis compromises tumor growth Tumors frequently experience hypoxia and serum limitation, which cause a harmful increase in fatty acid saturation. Studying kidney cancer, Ackerman et al. describe a protective role of lipid droplet-resident triglycerides: buffering of the cellular lipid saturation through exchange of mono-unsaturated fatty acids. Inhibiting triglyceride synthesis compromises solid tumor growth. [ABSTRACT FROM AUTHOR]

Lipid metabolism is essential for all major cell functions and has recently gained increasing attention in research and health studies. However, mathematical modeling by means of classical approaches such as stoichiometric networks and ordinary differential equation systems has not yet provided satisfactory insights, due to the complexity of lipid metabolism characterized by many different species with only slight differences and by promiscuous multifunctional enzymes. Here, we present an object-oriented stochastic model approach as a way to cope with the complex lipid metabolic network. While all lipid species are treated objects in the model, they can be modified by the respective converting reactions based on reaction rules, a hybrid method that integrates benefits of agent-based and classical stochastic simulation. This approach allows to follow the dynamics of all lipid species with different fatty acids, different degrees of saturation and different headgroups over time and to analyze the effect of parameter changes, potential mutations in the catalyzing enzymes or provision of different precursors. Applied to yeast metabolism during one cell cycle period, we could analyze the distribution of all lipids to the various membranes in time-dependent manner. The presented approach allows to efficiently treat the complexity of cellular lipid metabolism and to derive conclusions on the time- and location-dependent distributions of lipid species and their properties such as saturation. It is widely applicable, easily extendable and will provide further insights in healthy and diseased states of cell metabolism.

In this project, we hypothesize that cotton (Gossypium hirsutum) leaf temperature and the responses of leaf photosynthesis to temperature will change as the leaves expand and that differences between young and mature leaves will be associated with the proportion of saturated fatty acids in thylakoid and other membrane lipids. To that end, we studied main stem leaves obtained from plants growing in a temperature controlled greenhouse and at different times in the field season. We found that young leaves (∼5d old) had higher mid day temperatures, lower stomatal conductance and higher thermal optima as measured by ΦPSII temperature curves than did more mature leaves (∼13d old). Young leaves also had significant differences in fatty acid saturation with the warmer, young leaves having a higher proportion of palmitic acid (16:0) and lower linoleic acid (18:3) in total lipid extracts and higher 16:0 and lower palmitoleic acid (16:1) in the chloroplast membrane phosphoglycerides, digalactosyldiacylglycerol (in the greenhouse) and phosphatidylglycerol when compared with cooler, more mature leaves. Later in the growing season, leaf temperature, stomatal conductance and ΦPSII temperature curves for young and more mature leaves were similar and the proportion of 16:0 fatty acids decreased and 16:1 increased in phosphatidylglycerol. We conclude that changes in temperature as cotton leaves expand leads to alterations in the fatty acid composition of thylakoid and other membranes and, consequently, influence photosynthesis/temperature responses., (Copyright © 2013 Elsevier GmbH. All rights reserved.)