Reduction Of C18 Research Articles

Parkia platycephala pods in confined lamb diets: Fatty acid profile, ruminal biohydrogenation, and meat quality

This study was performed to evaluate the effects of replacing ground corn with Parkia platycephala pods (PPs) in lamb diets on the physicochemical characteristics of meat, the fatty acid profile in meat, and ruminal biohydrogenation (RBH). Twenty-eight castrated male lambs (20.05 ± 0.44 kg, 120 ± 10 days old) were distributed in a randomized block design constituting four treatments and seven replications. Four diets were formulated by replacing ground corn with PPs at increasing levels: 0 % PPs and 100 % ground corn (299.4 g/kg dry matter [DM]), 33 % substitution of ground corn (199.5 g/kg DM) with PPs (100.3 g/kg DM), 66 % substitution of ground corn (99.7 g/kg DM) with PPs (200.5 g/kg DM), and 100 % PPs (300.6 g/kg DM) and 0 % ground corn. The PPs resulted in a reduction in C18:1c9 intake; increased C12:0, C15:0, C18:1t9, C18:1t11, and C18:2n6; and reduced C18:0 in ruminal digesta, with a quadratic effect for C4:0 (P < 0.05). The RBH rate of C18:1c9 and C18:2n6 (P < 0.05) decreased as the PP levels in the diets increased. Regarding fatty acids in meat, there was a reduction in C16:1c9, C18:1c9, and cis-monounsaturated fatty acids and a quadratic effect for C14:1c9 and C18:2c9t11 (P < 0.05) as the PP levels in the diets increased. Levels of 66 % and 100 % PPs in the diets provided higher C18:2n6 in meat compared with the control diet (0 % PPs) and the diet containing 33 % PPs (P < 0.05). Under these experimental conditions, the replacement of corn with PPs in diets for lambs changed the fatty acid profile in the rumen digesta and lamb meat, promoting an increase in C18:1t11 in the rumen digesta. PPs can be used as an alternative ingredient in lamb feeding because they provide nutritional characteristics similar to those provided by corn.

Effects of estradiol on fatty acid composition and tissue structure of hepatopancreas in Procambarus clarkii

The hepatopancreas of Procambarus clarkii provides lipids and other nutrients for ovarian development and contains hormones such as estradiol related to ovarian development. During the development of the P. clarkii ovary, the hepatopancreas’ tissue structure and fatty acid content undergo corresponding changes. A controlled indoor experiment was conducted to investigate the effects of exogenous estradiol injection on the tissue structure and fatty acid content in the hepatopancreas of P. clarkii. The experiment consists of three experimental groups and one control group. The P. clarkii in the experimental group were injected with 5, 0.5, and 0.05 μg/(g body weight) of estradiol once every 5 days for 5 times and with normal saline injection as the control. After 25 days, the content of fatty acids and changes in tissue structure in the hepatopancreas were measured. The results showed that the main fatty acids in P. clarkii hepatopancreas were C18:4n, C20:3n, and EPA, and polyunsaturated fatty acid (PUFA) content was 57.17%±4.76%. Injecting estradiol mainly affected the content of C16:0, C16:1n, C18:0, C18:1n9, C18:2n, C18:3n6, C18:3n6, C18:4n, C20:1n, C20:2n, C20:3n, C20:4n3, C20:5n3, C22:n (n=1-4), C22:5n, and C22:6n in the hepatopancreas. Injecting estradiol significantly reduced the total content of PUFA in hepatopancreas with the reduction of C18:3n6, C18:4n, C20:3n, C20:4n3, C20:5n3 C22: n (n=1-4) (P&lt;0.05); Estradiol injection significantly increased the total content of monounsaturated fatty acid (MUFA) in hepatopancreas with the increase of C18:1n9, and C20:1n (P&lt;0.05); Injection of estradiol (0.05 μg/g) significantly increased the total content of saturated fatty acids (SFA) in the hepatopancreas (P&lt;0.05) with the increase of C16:0 and C18:0 (P&lt;0.05). Injecting estradiol can increase the volume and quantity of hepatopancreatic B cells, and the 5 μg/g group had the most obvious changes.

A stress-inducible protein regulates drought tolerance and flowering time in Brachypodium and Arabidopsis.

To cope with environmental stresses and ensure maximal reproductive success, plants have developed strategies to adjust the timing of their transition to reproductive growth. This has a substantial impact on the stress resilience of crops and ultimately on agricultural productivity. Here, we report a previously uncharacterized, plant-specific gene family designated as Regulator of Flowering and Stress (RFS). Overexpression of the BdRFS gene in Brachypodium distachyon delayed flowering, increased biomass accumulation, and promoted drought tolerance, whereas clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated knockout mutants exhibited opposite phenotypes. A double T-DNA insertional mutant in the two Arabidopsis (Arabidopsis thaliana) homologs replicated the effects on flowering and water deprivation seen in the B. distachyon CRISPR knockout lines, highlighting the functional conservation of the family between monocots and dicots. Lipid analysis of B. distachyon and Arabidopsis revealed that digalactosyldiacylglycerol (DGDG) and phosphatidylcholine (PC) contents were significantly, and reciprocally, altered in overexpressor and knockout mutants. Importantly, alteration of C16:0-containing PC, a Flowering Locus T-interacting lipid, associated with flowering phenotype, with elevated levels corresponding to earlier flowering. Co-immunoprecipitation analysis suggested that BdRFS interacts with phospholipase Dα1 as well as several other abscisic acid-related proteins. Furthermore, reduction of C18:3 fatty acids in DGDG corresponded with reduced jasmonic acid metabolites in CRISPR mutants. Collectively, we suggest that stress-inducible RFS proteins represent a regulatory component of lipid metabolism that impacts several agronomic traits of biotechnological importance.

Enhanced waste glycerol recycling by yeast for efficient biodiesel production: Towards waste biorefinery

The present study aimed to evaluate a new oleaginous yeast for biodiesel production with high potential of lipid accumulation in waste glycerol as a carbon source. Seven strains were isolated and identified using 5.8S-ITS based on their ability to assimilate glycerol. Naganishia diffluens CDU-M7rc showed the maximum lipid productivity (LP) of 881.9 mg L−1 d−1 at 96 h. Further optimization of pretreated waste glycerol (PWG) concentration enhanced the biomass yield to 20.3 g L−1 using 100 g L−1 PWG and enhanced lipid content to 34.36 dw% at 120 g L−1 PWG. However, the highest LP of 1.704 g L−1 d−1 was recorded at 100 g L−1 PWG, which represented 2.2-time more than the control. Using glucose as a carbon source, the dominant fatty acids in N. diffluens CDU-M7rc lipids were C16:0, C18:1, and C18:2, representing 23.91%, 55.45%, and 13.46% of total fatty acids, respectively. Utilization of PWG enhanced the proportion of C16:0 (33.39% of total fatty acids), with simultaneous reduction in C18:1 (41.12% of total fatty acids). Thus, supplementation of PWG enhanced saturated fatty acids proportion, which resulted in 10.8% reduction in the unsaturation degree of the produced biodiesel. All studied biodiesel characteristics showed acceptable values with the biodiesel international standards.

CerS1 but Not CerS5 Gene Silencing, Improves Insulin Sensitivity and Glucose Uptake in Skeletal Muscle.

Skeletal muscle is perceived as a major tissue in glucose and lipid metabolism. High fat diet (HFD) lead to the accumulation of intramuscular lipids, including: long chain acyl-CoA, diacylglycerols, and ceramides. Ceramides are considered to be one of the most important lipid groups in the generation of skeletal muscle insulin resistance. So far, it has not been clearly established whether all ceramides adversely affect the functioning of the insulin pathway, or whether there are certain ceramide species that play a pivotal role in the induction of insulin resistance. Therefore, we designed a study in which the expression of CerS1 and CerS5 genes responsible for the synthesis of C18:0-Cer and C16:0-Cer, respectively, was locally silenced in the gastrocnemius muscle of HFD-fed mice through in vivo electroporation-mediated shRNA plasmids. Our study indicates that HFD feeding induced both, the systemic and skeletal muscle insulin resistance, which was accompanied by an increase in the intramuscular lipid levels, decreased activation of the insulin pathway and, consequently, a decrease in the skeletal muscle glucose uptake. CerS1 silencing leads to a reduction in C18:0-Cer content, with a subsequent increase in the activity of the insulin pathway, and an improvement in skeletal muscle glucose uptake. Such effects were not visible in case of CerS5 silencing, which indicates that the accumulation of C18:0-Cer plays a decisive role in the induction of skeletal muscle insulin resistance.

Lipidomic analysis of human primary hepatocytes following LXR activation with GW3965 identifies AGXT2L1 as a main target associated to changes in phosphatidylethanolamine

Liver X receptor (LXR) agonists have the potential to alleviate obesity related diseases, particularly atherosclerosis. However, LXRs are transcriptional regulators that induce de novo lipogenesis and lipid accumulation in hepatocytes which represents a serious adverse effect. In this work, we sought to characterize the LXR agonist GW3965 effects on fatty acid (FA) and phospholipid (PL) remodelling and the correlation with gene expression in order to better understand the underlying effects leading to hepatic pathology upon LXR activation. Human primary hepatocytes treated for 48 h with GW3965 were analysed for changes in lipid metabolism gene expression by qPCR, variations in the FA profile was evaluated by GC-FID and in PL profiles using thin layer chromatography, ESI-MS and MS/MS analysis. Changes in cell membrane biochemical properties were studied using bilayer models generated with CHARMM-GUI. ELOLV6 and SCD1 mRNA increase was consistent with higher C16:1 and C18:1n9 at the expense of C16:0 and C18:0. The reduction of C18:2n6 and increase in C20:2n6 was in agreement with ELOVL5 upregulation. Phosphatydilethanolamine (PE) levels tended to decrease and phosphatidylinositol to increase; although differences did not reach significance, they correlated with changes in AGXT2L1, CDS1 and LPIN1 mRNA levels that were increased. The overall effect of GW3965 on PEs molecular profiles was an increase of long-chain polyunsaturated FA chains and a decrease of C16/C18 saturated and monounsaturated FAs chains. Additionally, PC (32:1) and PC (34:2) were decreased, and PC (36:1) and PC (34:1) were increased. AGXT2L1 is an enzyme with strict substrate specificity for phosphoethanolamine, which is converted into ammonia in GW3965-treated hepatocytes and could explain the PE reduction. In summary, LXR activation by GW3965 targets PE biosynthesis and FA elongation/desaturation, which tends to decrease PE in relation to total PL levels, and remodelling of PC and PE molecular species. We identified the human AGXT2L1 gene as induced by LXR activation by both synthetic and endogenous agonist treatment. The increase in acetaldehyde-induced oxidative stress, and in the lipid species identified have the potential to enhance the inflammatory process and impair membrane function. Future studies should focus on inhibition of AGXT2L1 activity with the aim of reverting the steatosis induced by LXR activation.

Effects of disrupted omega-3 desaturase gene construct on fatty acid composition and expression of four fatty acid biosynthetic genes in transgenic Chlorella vulgaris

This study demonstrated the genetic modification of Chlorella vulgaris by introducing a copy of disrupted omega-3 desaturase (ω-3 FAD) gene into its genome to study the effect on fatty acid biosynthesis pathway. Results revealed that the expression of endogenous ω-3 FAD gene in transgenic lines (C28 and C30) was temporarily suppressed during the early stage of sub-culture and then reactivated subsequently after six months of alternate sub-culturing. Furthermore, the endogenous ω-3 FAD expression was found to be upregulated to >3-fold without any notable changes in C18:3n3 composition when cultured under nitrate-deficient medium. Interestingly, a significant shift in fatty acid saturation profile towards the production of higher C16:0 was observed along with a reduction in C18:1 composition in transgenic lines. In addition, PCR walking experiment confirmed that the entire T-DNA region and vector backbone were co-transferred and randomly integrated into the host genome. These findings provide valuable insight in understanding the regulation of fatty acid biosynthesis pathway in C. vulgaris and could pave the way for further genetic improvement of the species for various downstream applications.

Characterization of Nicotiana tabacum plants expressing hybrid genes of cyanobacterial Δ9 or Δ12 acyl-lipid desaturases and thermostable lichenase

We established transgenic lines of Nicotiana tabacum expressing hybrid genes of Synechocystis sp. PCC 6803 Δ12 (desA) acyllipid desaturase and Synechococcus vulcanus Δ9 (desC) acyllipid desaturase with or without sequence coding for transit peptide of Rubisco small subunit of Arabidopsis thaliana under control of a constitutive promoter. Reliable increase of linoleic acid portion (C18:2; Δ9,12) accompanied with decrease of α-linolenic acid (C18:3; Δ9,12,15) relative amount was detected for plants expressing hybrid desA::licBM3 gene. No reliable changes were detected in fatty acid profiles and unsaturation index of plants transformed with Δ9 desaturase gene desC::licBM3 lacking signals of intracellular targeting while expression of this gene with Arabidopsis thaliana Rubisco small subunit transit peptide sequence caused growth of C18:3 α-linolenic acid part simultaneously with reduction of C18:2 linoleic acid part, as well as increase of unsat-uration index. No changes in relative amount of Δ9-monounsaturated fatty acids were observed in any of studied lines. All plants expressing desaturase genes exhibited enhanced levels of superoxide dismutase (SOD) activity after cold treatment in contrast to control lines with suppressed SOD activity after cold treatment.

Variation in the composition and oxidative stability of commercial rapeseed oils during their shelf life

This study was conducted to evaluate the variation in chemical composition and oxidative stability of 21 different commercial rapeseed oils. Their composition was estimated immediately after opening the packaging and for the same oils at the end of their induction period. The oxidation of oils was conducted at 110°C in an oven test, while the induction time was determined in a Rancimat test at the same temperature. It was found that the initial ratio of n‐6 to n‐3 fatty acids was close to 2.2 to 1. These oils differed mainly in minor acids, such as C16:0 and C20:1. At the end of their shelf life, a reduction of C18:2 and C18:3 acids shares was found, which was accompanied by a slight increase of n‐6 to n‐3 ratio. The most variable oil‐soluble compounds of oils were carotenoids, chlorophylls, and phenolics, while the tocopherols were the most stable. Induction time was the most positively correlated with the oil‐soluble phenolics (r = 0.76 for all samples) and chlorophylls (r = 0.77 for refined oils), while carotenoids generally acted as pro‐oxidants (r = −0.66 for all oils). The degradation degree of tested compounds during oxidation (on average) was as follows: phytosterols &gt; tocopherols &gt; carotenoids &gt; phenolic compounds &gt; chlorophylls.Practical applications: Rapeseed oil is a popular edible oil and may be a good source of oil‐soluble vitamins, polyunsaturated fatty acids and antioxidants in human diet. However, its composition depends mainly on the rape genotypes, cultivation conditions, industrial practices, and storage conditions. In this study, we evaluated the variability in chemical composition of typical commercial rapeseed oils immediately after opening the package and at the end of their induction time. We have shown that fatty acids composition of tested oils was relatively stable, while their minor compounds content were significantly different. Oils oxidative stability was mainly related to phenolic compounds. These informations are important both for the consumers (nutrition facts), and industry (phenolics as antioxidants).Score plot of the two first principal components after PCA analysis of oil‐soluble minor components of fresh (1‐21) and oxidized (1’‐21’) rapeseed oils with an indication by ellipses samples of cold pressed oils before (green) and after oxidation (yellow); 1‐3 – cold pressed, unrefined oils, 4‐21 – refined mixture of pressed and extracted oils.

TCF/Lef1-Mediated Control of Lipid Metabolism Regulates Skin Barrier Function

Defects in the function of the skin barrier are associated with a wide variety of skin diseases, many of which are not well characterized at the molecular level. Using Lef1 (lymphoid enhancer-binding factor 1) dominant-negative mutant mice, we demonstrate here that altered epidermal TCF (T cell factor)/Lef1 signaling results in severe impairment of the stratum corneum skin barrier and early postnatal death. Barrier defects were accompanied by major changes in lipid composition and ultrastructural abnormalities in assembly and extrusion of lipid lamellae of the interfollicular epidermis, as well as abnormal processing of profilaggrin. In contrast, tight-junction formation and stratified organization of the interfollicular epidermis was not obviously disturbed in Lef1 mutant mice. Molecular analysis revealed that TCF/Lef1 signaling regulates expression of lipid-modifying enzymes, such as Elovl3 and stearoyl coenzyme A desaturase 1 (SCD1), which are key regulators of barrier function. Promoter analysis and chromatin immunoprecipitation experiments indeed showed that SCD1 is a direct target of Lef1. Together, our data demonstrate that functional TCF/Lef1 signaling governs important aspects of epidermal differentiation and lipid metabolism, thereby regulating skin barrier function.

Up-regulated expression of desaturase genes of Mucor rouxii in response to low temperature associates with pre-existing cellular fatty acid constituents

Transcriptional response of desaturase genes to low temperature was investigated in the dimorphic fungus Mucor rouxii. The two morphological forms of M. rouxii, yeast-like and mycelial cells containing different fatty acid profiles were shifted from 30 to 10°C. Both cultures exhibited significantly altered fatty acid composition, whose content in polyunsaturated fatty acids increased as consequence of the temperature shift and was accompanied by a reduction of C18:1Δ(9) about 2 h after the temperature shift. These changes were particularly significant in phosphatidylcholine and phosphatidylethanolamine fractions. Moreover, the fatty acid profiles of monoacylglycerol and diacylglycerol were also modulated in response to the lower temperature of incubation. The changes of membrane lipids of M. rouxii were due to the cold-induced expression of Δ(9)-, Δ(12)- and Δ(6)-desaturase genes. Although the mRNA levels of the three desaturases were transiently induced by lowering the temperature, the pre-existing composition of fatty acid profiles of mycelial and yeast-like forms of M. rouxii may have lead to different expression profiles of desaturase genes that modified their membrane physical state under cold shock. While expression of Δ(12)-desaturase gene contributed mainly to cold acclimation of mycelia, Δ(9)-desaturase expression was the main transcript identified in the yeast-like culture after temperature shift.

A Critical Role for Ceramide Synthase 2 in Liver Homeostasis: I. ALTERATIONS IN LIPID METABOLIC PATHWAYS

Ceramide is an important lipid signaling molecule that plays critical roles in regulating cell behavior. Ceramide synthesis is surprisingly complex and is orchestrated by six mammalian ceramide synthases, each of which produces ceramides with restricted acyl chain lengths. We have generated a CerS2 null mouse and characterized the changes in the long chain base and sphingolipid composition of livers from these mice. Ceramide and downstream sphingolipids were devoid of very long (C22-C24) acyl chains, consistent with the substrate specificity of CerS2 toward acyl-CoAs. Unexpectedly, C16-ceramide levels were elevated, and as a result, total ceramide levels were unaltered; however, C16-ceramide synthesis in vitro was not increased. Levels of sphinganine were also significantly elevated, by up to 50-fold, reminiscent of the effect of the ceramide synthase inhibitor, fumonisin B1. With the exceptions of glucosylceramide synthase and neutral sphingomyelinase 2, none of the other enzymes tested in either the sphingolipid biosynthetic or degradative pathways were significantly changed. Total glycerophospholipid and cholesterol levels were unaltered, although there was a marked elevation in C18:1 and C18:2 fatty acids in phosphatidylethanolamine, concomitant with a reduction in C18:0 and C20:4 fatty acids. Finally, differences were observed in the biophysical properties of lipid extracts isolated from liver microsomes, with membranes from CerS2 null mice displaying higher membrane fluidity and showing morphological changes. Together, these results demonstrate novel modes of cross-talk and regulation between the various branches of lipid metabolic pathways upon inhibition of very long acyl chain ceramide synthesis.

Disappearance of docosahexaenoic and eicosapentaenoic acids from cultures of mixed ruminal microorganisms.

Previous studies showed conflicting results regarding the ability of ruminal microorganisms to hydrogenate docosahexaenoic acid (C22:6, DHA) and eicosapentaenoic acid (C20:5, EPA). To determine the disappearance of DHA and EPA from mixed ruminal cultures, 2 ruminal in vitro experiments were conducted using graded levels of DHA and EPA. The first experiment examined DHA added at 0, 5, 10, 15, and 20 mg per culture flask. In the second experiment, EPA was added at 0, 5, 10, and 15 mg per culture flask. Docosahexaenoic acid and EPA were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0, 12, and 24 h for fatty acid analysis by gas liquid chromatography. After 24 h of incubation, 4.1, 4.1, 4.0, and 3.3 mg of DHA disappeared from the 5, 10, 15, and 20 mg of DHA cultures, respectively. In the second experiment, 5, 8.3, and 7.1 mg of EPA disappeared after 24 h of incubation for the 5-, 10-, and 15-mg EPA cultures, respectively. Addition of DHA to cultures increased trans-C18:1 fatty acid accumulation by 105, 91, 82, and 74% for the 5, 10-, 15-, and 20-mg cultures, respectively, compared with control. The addition of EPA increased trans-C18:1 fatty acid accumulation by 56, 64, and 55% for the 5-, 10-, and 15-mg EPA cultures, respectively, compared with control. Addition of DHA and EPA to cultures caused a reduction in C18:1 n-9 and C18:2 n-6 biohydrogenation compared with control. Results from these experiments clearly demonstrate the ability of ruminal microorganism to transform DHA and EPA to other fatty acids causing their disappearance from cultures.

Effects of the extensive culture system as finishing production strategy on biometric and chemical parameters in rainbow trout

The effect of finishing extensive farming period, to reduce fat content and manipulate the fatty acid profile of fish muscle, was evaluated in rainbow trout. Fish were stocked in an artificial lake, in which fish were fed only on naturally available nutrients with no supply of artificial feed, for different lengths of time from 0 to 120 days. No weight loss was noted during the whole finishing period while total length increased from 228±7 to 269±3 mm and the condition factor decreased from 1.41±0.04 to 0.89±0.02. The total fat content of the fillets decreased considerably from 4.7±0.6% at the beginning to 2.4±0.4% and 0.7±0.2% after 45 and 120 days respectively. Fillet fatty acid composition was affected by the time of stocking in the extensive farm. In contrast to the reduction in C18:1n-9, C18:2n-6, total monounsaturated fatty acid and total n-6 percent values, an increase in the C20:5n-3, C22:6n-3, total polyunsaturated fatty acid and total n-3 percent values was observed. It was shown that while other finishing strategies for salmonids have some disadvantages, the extensive culture system seems to be a potentially useful tool for increasing the general quality of the end product.

The effect of duration of feeding oilseeds to dairy cows on the persistency of response in milk fatty acid composition

There is much interest in the manipulation of the fatty acid composition of milk fat so as to improve its health characteristics in the human diet. In an earlier study there was an indication that the concentration of fatty acids in milk may change with time when feeding whole oilseeds rich in polyunsaturated fatty acids (PUFA). In particular a tendency for an increase in CLA and C18:1 and a reduction in C18:2 and C18:3 concentrations with time were seen. The present study was therefore undertaken to examine the changes in the fatty acid composition of milk from high yielding dairy cows fed diets rich in monounsaturated fatty acids (MUFA) or PUFA over an extended period.

Effect of feeding different fat supplements on the fatty acid composition of goat milk

The effect of feeding dietary fat supplements on the fatty acid composition of goat milk was examined. Inclusion of canola and soybean ( 80 20 ; w w ) oilseed supplement protected from ruminal hydrogenation, significantly increased the proportion of C18:1 (oleic acid), C18:2 (linoleic acid) and decreased the proportion of C16:0 (palmitic acid) and C14:0 (myristic acid), while there was a small increase in C18:0 (stearic acid). Feeding protected cotton seed significantly increased C18:2 and C18:0, but there was a reduction in C18:1 while the C16:0 was unchanged. When combinations of protected cotton seed and protected-canola soybean ( 80 20 ; w w ) were fed, a level of 20–25% incorporation of protected cotton seed was sufficient to inhibit the desaturase enzyme, with an increase in the proportion of C18:0. In contrast, feeding calcium salts of fatty acids, a predominantly saturated fatty acid supplement, increased C16:0 and reduced C10:0 (decanoic acid) and C14:0. Feeding fat supplements of different fatty acid compositions and varying levels of inertness in the rumen will enable significant manipulation of the fatty acid composition of milk fat.