Delta-6 Desaturase Research Articles

Participation of oleic acid in the formation of the aortic aneurysm in Marfan syndrome patients

Marfan syndrome (MFS) is associated with progressive aortic dilatation and endothelial dysfunction that lead to early acute dissection and rupture of the aorta and sudden death. Alteration in fatty acid (FA) metabolism can stimulate nitric oxide (NO) overproduction which increases the activity of the inducible form of NO synthase (iNOS) that is involved in endothelial dysfunction. We evaluated the participation of FA in the formation of thoracic aneurysms in MFS and its relation to the iNOS. Oleic acid (OA), iNOS, citrulline, nitrates and nitrites, TGF-β1, TNF-α, monounsaturated FA and NO synthase activity were significantly increased (p<0.05) in tissue from the aortas of MFS. Saturated FA, eNOS and HDL were significantly decreased (p<0.05). Arachidonic acid, delta-9 desaturase tended to increase and histological examination showed an increase in cystic necrosis, elastic fibers and collagen in MFS. The increase in OA contributes to the altered pathway of iNOS, which favors endothelial dysfunction and formation of the aortic aneurysms in MFS.

Maternal Plasma DHA Levels Increase Prior to 29 Days Post-LH Surge in Women Undergoing Frozen Embryo Transfer: A Prospective, Observational Study of Human Pregnancy.

Docosahexaenoic acid (DHA) is an important fatty acid required for neurological development but its importance during early fetal neurological organogenesis is unknown. This study aimed to assess plasma fatty acid changes in early pregnancy in women undergoing natural cycle-frozen embryo transfer as a means of achieving accurately timed periconceptual sampling. Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinizing hormone (LH) surge, and at 18, 29, and 45 d post-LH surge and fatty acids were analyzed using gas chromatography. This study took place at the Assisted Conception Unit, Glasgow Royal Infirmary, Scotland. Plasma fatty acid concentrations and influence of twin pregnancies on DHA plasma concentration were measured. In pregnant women, there was a rapid, early increase in the maternal rate of change of plasma DHA concentration observed by 29 d post-LH surge (mean ± SD, from 0.1 ± 1.3 to 1.6 ± 2.9 nmol DHA per mL plasma per day). This early pressure to increase plasma DHA concentration was further emphasized in twin pregnancies where the increase in DHA concentration over 45 d was 2-fold higher than in singleton pregnancies (mean ± SD increase, 74 ± 39 nmol/mL vs 36 ± 40 nmol/mL). An index of delta-6 desaturase activity increased 30% and positively correlated with the rate of change of DHA concentration between 18 and 29 d post-LH surge (R2 adjusted = 41%; P = .0002). DHA was the only fatty acid with a continual accelerated increase in plasma concentration and a positive incremental area under the curve (mean ± SD, 632 ± 911 nmol/mL × d) during the first 45 d of gestation. An increase in maternal plasma DHA concentration is initiated in human pregnancy prior to neural tube closure which occurs at 28 d gestation.

Red Blood Cell Fatty Acids and Incident Diabetes Mellitus in the Women's Health Initiative Memory Study.

ContextThe relations between dietary and/or circulating levels of fatty acids and the development of type 2 diabetes is unclear. Protective associations with the marine omega-3 fatty acids and linoleic acid, and with a marker of fatty acid desaturase activity delta-5 desaturase (D5D ratio) have been reported, as have adverse relations with saturated fatty acids and D6D ratio.ObjectiveTo determine the associations between red blood cell (RBC) fatty acid distributions and incident type 2 diabetes.DesignProspective observational cohort study nested in the Women’s Health Initiative Memory Study.SettingGeneral population.SubjectsPostmenopausal women.Main Outcome MeasuresSelf-reported incident type 2 diabetes.ResultsThere were 703 new cases of type 2 diabetes over 11 years of follow up among 6379 postmenopausal women. In the fully adjusted models, baseline RBC D5D ratio was inversely associated with incident type 2 diabetes [Hazard Ratio (HR) 0.88, 95% confidence interval (CI) 0.81–0.95) per 1 SD increase. Similarly, baseline RBC D6D ratio and palmitic acid were directly associated with incident type 2 diabetes (HR 1.14, 95% CI 1.04–1.25; and HR 1.24, 95% CI 1.14–1.35, respectively). None of these relations were materially altered by excluding incident cases in the first two years of follow-up. There were no significant relations with eicosapentaenoic, docosahexaenoic or linoleic acids.ConclusionsWhether altered fatty acid desaturase activities or palmitic acid levels are causally related to the development of type 2 diabetes cannot be determined from this study, but our findings suggest that proportions of certain fatty acids in RBC membranes are associated with risk for type 2 diabetes.

Long-chain saturated and monounsaturated fatty acids associate with development of premature infants up to 18 months of age

Myelination is important perinatally and highly dependent on long-chain saturated and monounsaturated fatty acids. Long-chain polyunsaturated fatty acids, nowadays often supplemented, inhibit oleic acid synthesis. Using data from a premature cohort, we studied if nervonic, lignoceric and oleic acids correlated to growth and early development up to 18 months corrected age. Small for gestational age infants had lower concentrations than infants appropriate for gestational age. Only oleic acid was negatively correlated to long-chain polyunsaturated fatty acids. Oleic and lignoceric acids correlated to social interaction at one month, and nervonic acid to mental, psychomotor and behavioral development at 6, 10 and 18 months, also when adjusted for several confounders. Negative association between oleic acid and long-chain polyunsaturated fatty acids suggests inhibition of delta-9 desaturase, and nervonic acid´s divergent correlation to lignoceric and oleic acids suggests different metabolism in neonatal period. Our results may have implications for the supplementation of premature infants.

Fatty acid metabolism is altered in non-alcoholic steatohepatitis independent of obesity

BackgroundNon-alcoholic steatohepatitis (NASH) is associated with changes in fatty acid (FA) metabolism. However, specific changes in metabolism and hepatic mRNA expression related to NASH independent of simple steatosis, obesity and diet are unknown. MethodsLiver histology, serum and liver FA composition and estimated enzyme activities based on the FA ratios in cholesteryl esters and triglycerides were assessed in 92 obese participants of the Kuopio Obesity Surgery Study (KOBS) divided to those with normal liver, steatosis or NASH (30 men and 62 women, age 46.8±9.5years (mean±SD), BMI 44.2±6.2kg/m2). Plasma FA composition was also investigated in the Metabolic Syndrome in Men (METSIM) Study (n=769), in which serum alanine aminotransferase (ALT) was used as a marker of liver disease. ResultsObese individuals with NASH had higher activity of estimated activities of delta-6 desaturase (D6D, p<0.002) and stearoyl-CoA desaturase 1 (SCD1, p<0.002) and lower activity of delta-5 desaturase (D5D, p<0.002) when compared to individuals with normal liver. Estimated activities of D5D, D6D and SCD1 correlated positively between liver and serum indicating that serum estimates reflected liver metabolism. Accordingly, NASH was associated with higher hepatic mRNA expression of corresponding genes FADS1, FADS2 and SCD. Finally, differences in FA metabolism that associated with NASH in obese individuals were also associated with high ALT in the METSIM Study. ConclusionsWe demonstrated alterations in FA metabolism and endogenous desaturase activities that associate with NASH, independent of obesity and diet. This suggests that changes in endogenous FA metabolism are related to NASH and that they may contribute to the progression of the disease.

A genome-wide association study of n-3 and n-6 plasma fatty acids in a Singaporean Chinese population.

Polyunsaturated fatty acids (PUFAs) have a major impact on human health. Recent genome-wide association studies (GWAS) have identified several genetic loci that are associated with plasma levels of n-3 and n-6 PUFAs in primarily subjects of European ancestry. However, the relevance of these findings has not been evaluated extensively in other ethnic groups. The primary aim of this study was to evaluate for genetic loci associated with n-3 and n-6 PUFAs and to validate the role of recently identified index loci using data from a Singaporean Chinese population. Using a GWAS approach, we evaluated associations with plasma concentrations of three n-3 PUFAs [alphalinolenic acid (ALA), eicosapentaenoic acid and docosahexaenoic acid], four n-6 PUFAs [linoleic acid (LA), gammalinolenic acid, dihomogammalinolenic acid (DGLA) and arachidonic acid], and estimates of delta-5 desaturase and delta-6 desaturase activities among the participants (N=1361) of the Singaporean Chinese Health Study. Our results reveal robust genome-wide associations (p value <5×10(-8)) with ALA, all four n-6 PUFAs, and delta-6 desaturase activity at the FADS1/FADS2 locus. We further replicated the associations between common index variants at the NTAN1/PDXDC1 locus and n-6 PUFAs LA and DGLA, and between the JMJD1C locus and n-6 PUFA LA (p value between 0.0490 and 9.88×10(-4)). These associations were independent of dietary intake of PUFAs. In aggregate, we show that genetic loci that influence plasma concentrations of n-3 and n-6 PUFAs are shared across different ethnic groups.

Effects of two-months balanced diet in metabolically healthy obesity: lipid correlations with gender and BMI-related differences.

BackgroundNowadays no researches has been performed on fatty acid profile (FA) and desaturase activity in metabolically healthy obesity (MHO). The aim of this study was to assessed gender and BMI-related difference in FA, estimated desaturase activities and the efficacy on metabolic changes produced by 2-months well-balance diet in MHO subjects.MethodsIn 103 MHO subjects (30/73 M/F; age:42.2 ± 9.5) FA, estimated desaturase activity, body composition (by DXA), Body Mass Index (BMI), lipid profile, adipokines (leptin, adiponectin, grelin, glucagon-like peptide-1), insulin resistence (by Homestasis metabolic assessment), C-reactive proteine, Atherogenic index of plasma (AIP) and Body Shape Index (ABSI) have been assessed. Gender and BMI related difference have been evaluated and the efficacy produced by 2-months well-balance diet has been considered.ResultsAt baseline, obese subjects, compared to overweight, show a significantly higher oleic (p <0.050), monounsaturated fatty acids (p <0.040), C18:0 delta-9 desaturase activity (D9D) (p <0.040) and lower linoleic acid (p <0.020), polyunsaturated fatty acids (p <0.020) and n-6 LCPUFA (p <0.010). Concerning gender-related difference, women show a significantly higher arachidonic acid (p <0.001), polyunsaturated fatty acids (p <0.001), n-6 LCPUFA (p <0.002), and lower monounsaturated fatty acids (p <0.001), D6D activity (p <0.030), C18:0 D9D (0.000) and C16:0 D9D (p <0.030). The 2-months diet was associated with a significantly increase in arachidonic acid (p = 0.007), eicosapentaenoic acid (p = 0.030), docosahexaenoic acid (p <0.001), long chain omega 3 polyunsaturated fatty acids (n-3 LCPUFA) (p <0.001), delta-5 desaturase activity (D5D) (p = 0.002), glucagon like peptide-1 (p <0.001) and a significant decrease in palmitoleic acid (p = <0.030), n-6/n-3 LCPUFA (p <0.001), insulin resistance (p = 0.006), leptin (p = 0.006), adiponectin (p <0.001), grelin (p = 0.030), CRP (p = 0.004), BMI (p <0.001) and android fat mass (p <0.001).ConclusionsThe balanced diet intervention was effective in improving metabolic indices.

Longitudinal circulating concentrations of long-chain polyunsaturated fatty acids in the third trimester of pregnancy in gestational diabetes.

Gestational diabetes mellitus is a common complication of pregnancy. Long-chain polyunsaturated fatty acids (LCPUFA) are essential for fetal neurodevelopment. Docosahexaenoic acid (DHA) is the predominant n-3 LCPUFA in the brain and retina. Circulating absolute concentrations of total n-3 and n-6 LCPUFAs rise during normal pregnancy. It remains unclear whether gestational diabetes may affect the normal rise in circulating concentrations of LCPUFAs in the third trimester of pregnancy - a period of rapid fetal neurodevelopment. This study aimed to address this question. In a prospective singleton pregnancy cohort, fatty acids in fasting plasma total lipids were measured at 24-28 and 32-35 weeks of gestation in women with (n = 24) and without gestational diabetes mellitus (n = 116). Fatty acid desaturase activity indices were estimated by relevant product-to-precursor fatty acid ratios. Dietary nutrient intakes were estimated by a food frequency questionnaire. Plasma absolute concentrations of total n-6 LCPUFAs rose significantly between 24-28 and 32-35 weeks of gestation in women with or without gestational diabetes, whereas total n-3 LCPUFAs and DHA concentrations rose significantly only in women without gestational diabetes (all P < 0.01). Delta-5 desaturase indices (20:4n-6/20:3n-6) were similar, but delta-6 desaturase indices (18:3n-6/18:2n-6) were significantly lower in women with gestational diabetes at 32-35 weeks of gestation. Dietary intakes of all fatty acids were comparable. The normal rise in circulating absolute concentrations of DHA and total n-3 LCPUFAs in the third trimester of pregnancy may be compromised in gestational diabetes, probably due to impaired synthesis or mobilization rather than dietary intake difference.

Fatty acid composition of adipose tissue triglycerides in obese diabetic women after bariatric surgery: a 2-year follow up.

Bariatric surgery is the most effective method in the treatment of obesity and type 2 diabetes (T2DM). The aim of this study was to evaluate the effects of different types of bariatric procedures on remission of T2DM and on the fatty acid composition in subcutaneous adipose tissue. Patients included obese diabetic women who underwent bariatric surgery: biliopancreatic diversion (BPD), n=8, laparoscopic gastric banding (LAGB), n=9 or laparoscopic greater curvature plication (LGCP), n=12. Anthropometric characteristics and fatty acid composition of adipose tissue (FA AT) were analyzed before surgery, then 6 months and 2 years after surgery. FA AT was analyzed by gas chromatography. Diabetes remission was estimated. BPD was most efficient in inducing a remission of diabetes (p=0.004). Significantly higher increases in lauric (12:0), myristoleic (14:1n-5) and palmitoleic (16:1n-7) acids and delta-9 desaturase were found two years after BPD, suggesting higher lipogenesis in adipose tissue. Docosatetraenoic acid (22:4n-6) increased significantly after BPD, while docosapentaenoic acid (22:5n-3) decreased 6 months after BPD and increased after 2 years. No changes were found after LAGB and LGCP after 2 years. Bariatric surgery led to significant changes in the fatty acid composition of subcutaneous adipose tissue in severely obese diabetic women after six months and two years, and was partly influenced by the type of surgery used.

Mendelian randomization studies of biomarkers and type 2 diabetes.

Many biomarkers are associated with type 2 diabetes (T2D) risk in epidemiological observations. The aim of this study was to identify and summarize current evidence for causal effects of biomarkers on T2D. A systematic literature search in PubMed and EMBASE (until April 2015) was done to identify Mendelian randomization studies that examined potential causal effects of biomarkers on T2D. To replicate the findings of identified studies, data from two large-scale, genome-wide association studies (GWAS) were used: DIAbetes Genetics Replication And Meta-analysis (DIAGRAMv3) for T2D and the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) for glycaemic traits. GWAS summary statistics were extracted for the same genetic variants (or proxy variants), which were used in the original Mendelian randomization studies. Of the 21 biomarkers (from 28 studies), ten have been reported to be causally associated with T2D in Mendelian randomization. Most biomarkers were investigated in a single cohort study or population. Of the ten biomarkers that were identified, nominally significant associations with T2D or glycaemic traits were reached for those genetic variants related to bilirubin, pro-B-type natriuretic peptide, delta-6 desaturase and dimethylglycine based on the summary data from DIAGRAMv3 or MAGIC. Several Mendelian randomization studies investigated the nature of associations of biomarkers with T2D. However, there were only a few biomarkers that may have causal effects on T2D. Further research is needed to broadly evaluate the causal effects of multiple biomarkers on T2D and glycaemic traits using data from large-scale cohorts or GWAS including many different genetic variants.

Desaturase Activity Is Associated With Weight Status and Metabolic Risk Markers in Young Children.

Activity of delta-9, delta-6, and delta-5 desaturases (D9D, D6D, D5D) are associated with obesity, insulin resistance, and dyslipidemia. To investigate the association of estimated desaturase activities with weight status, insulin resistance, and dyslipidemia in children, cross-sectionally and longitudinally. The IDEFICS (Identification and Prevention of Dietary- and Lifestyle-Induced Health Effects in Children and Infants) cohort study was used, with examinations at baseline (T0) and after 2 years (T1). Children aged 2 to less than 10 years from eight European countries were recruited in kindergartens/primary schools. Children with available data on fatty acids, outcome, and covariate information were included in the analyses. Whole blood fatty acids were analyzed in 2600 children at baseline. D9D (16:1n-7/16:0), D6D (20:3n-6/18:2n-6), and D5D (20:4n-6/20:3n-6) activities were estimated from product-precursor fatty acids ratios. Body mass index (BMI), Homeostatic Model Assessment index, and high-density lipoprotein cholesterol (HDL), and triglycerides (TG) served as outcomes for weight status, insulin resistance, and dyslipidemia, respectively. Linear and logistic regression and repeated measures models were used to assess the cross-sectional and longitudinal associations between desaturase activity and outcomes. In the cross-sectional analysis, D9D and D6D were positively associated with BMI and TG z-scores and inversely with HDL z-scores. D5D was inversely associated with BMI and TG z-scores (ie, a D5D increase of 1 unit is associated with a BMI z-score decrease of 0.07 and a 28% lower odds ratio for TG ≥ 75th percentile). Longitudinally, similar associations were found for T0 desaturase activities with BMI and for T0 D6D with HDL at follow-up (T1). Baseline D6D and D5D were positively associated with the change of HDL z-score from T0 to T1, and D6D with the change of Homeostatic Model Assessment index z-score. Desaturase activities are associated with metabolic risk markers already in young children and appear to predict the metabolic risk.

Relationship of Circulating Fatty Acid Profile to Metabolic Disorders Associated with Insulin Resistance

Relationship of Circulating Fatty Acid Profile to Metabolic Disorders Associated with Insulin Resistance

Synergistic Effect of Oleanolic Acid on Aminoglycoside Antibiotics against Acinetobacter baumannii.

Difficulties involved in treating drug-resistant pathogens have created a need for new therapies. In this study, we investigated the possibility of using oleanolic acid (OA), a natural pentacyclic triterpenoid, as a natural adjuvant for antibiotics against Acinetobacter baumannii. High concentrations of OA can kill cells, partly because it generates reactive oxygen species. Measurement of the fractional inhibitory concentration (FIC) for OA and time-kill experiments demonstrated that it only synergizes with aminoglycoside antibiotics (e.g., gentamicin, kanamycin). Other classes of antibiotics (e.g., ampicillin, rifampicin, norfloxacin, chloramphenicol, and tetracycline) have no interactions with OA. Microarray and quantitative reverse transcription-PCR analysis indicated that genes involved in ATP synthesis and cell membrane permeability, the gene encoding glycosyltransferase, peptidoglycan-related genes, phage-related genes, and DNA repair genes were upregulated under OA. OA highly induces the expression of adk, which encodes an adenylate kinase, and des6, which encodes a linoleoyl-CoA desaturase, and deletion of these genes increased FICs; these observations indicate that adk and des6 are involved in the synergism of OA with aminoglycosides. Data obtained using 8-anilino-1-naphthalenesulfonic acid, fluorescence-conjugated gentamicin, and membrane fatty acid analysis indicates that adk and des6 are involved in changes in membrane permeability. Proton-motive force and ATP synthesis tests show that those genes are also involved in energy metabolism. Taken together, our data show that OA boosts aminoglycoside uptake by changing membrane permeability and energy metabolism in A. baumannii.

Expression of Shewanella frigidimarina fatty acid metabolic genes in E. coli by CRISPR/cas9-coupled lambda Red recombineering.

To construct a clustered, regularly interspaced, short palindromic repeats (CRISPR)/cas9 system and use this system to obtain a recombinant Escherichia coli strain possessing the fatty acid metabolism genes from a lipid-rich marine bacterium. The fatty acid regulatory transcription factor (fadR), delta9 (Δ(9) desaturase) and acetyl-CoA carboxylase (acc) genes were cloned from Shewanella frigidimarina. The fatty acid regulatory transcription factor (fadD) and phosphoenolpyruvate carboxylase inactivated strains were used to construct the fadR/delta9 and acc knock-in strains, which are both markerless and "scar"-less, and identified the change in fatty acid composition in the recombinant strains. There was no change in fatty acid composition between the wild-type strain and recombinant strains. All strains had 11:0, 12:0, 13:0, 14:0, 15:0, 16:0, 17:1, 17:0 and 18:0 fatty acids, with 16:0 and 18:0 fatty acids being dominant. The total lipid content of each recombinant strain was higher than the wild-type strain, with a maximum of 13.1 %, nearly 5.3 % higher than wild-type strain. The CRISPR/cas9 system, in conjunction with λ-Red recombinases, can rapidly and efficiently edit the E. coli genome. The CRISPR/cas9 recombineering machinery can be modified to select biotechnologically-relevant bacteria other than E. coli.

Effects of different dietary soybean oil levels on growth, lipid deposition, tissues fatty acid composition and hepatic lipid metabolism related gene expressions in blunt snout bream (Megalobrama amblycephala) juvenile

Soybean oil (SO) is widely used in freshwater aqua-feeds in China. However, little information is available about the effects of dietary SO levels on lipid deposition and hepatic lipid metabolism in fish. This study evaluated effects of different dietary soybean oil (SO) levels on growth performance, lipid deposition, tissues fatty acid compositions and hepatic lipid metabolism related gene expressions in blunt snout bream (Megalobrama amblycephala). Fish (average weight 0.34±0.01g) were fed five experimental diets containing 0% (0%SO), 20% (20%SO), 32% (32%SO), 56% (56%SO) and 100% (100%SO) SO in dietary lipid, and a diet containing 100% fish oil (100%FO). The body weight gain of fish fed 20%SO and 100%FO diets were significantly higher than in the other groups. Hepatic lipid content increased with incremental dietary SO level. The percentages of 18:2n−6 in the liver and muscle significantly increased with increasing dietary SO level. In the fish fed 56%SO and 100%SO diets 20:4n−6 content significantly increased in the liver and muscle suggesting the capacity of blunt snout bream to convert C18 fatty acids (PUFAs) to C20/22 fatty acids. However, increasing dietary SO level up-regulated acyl-CoA delta-9 desaturase and down-regulated peroxisome proliferator-activated receptors-α and -β, which might be responsible for the high 18:2n−6 content. It is suggested that supplementation of 20% soybean oil (8% lipid in diet) could improve blunt snout bream juvenile growth. However, an excess of 18:2n−6 in SO supplemented diets modified the expressions of lipid metabolism-related genes which induced lipid deposition. Statement of relevanceThe present study was conducted to evaluated the effects of different dietary soybean oil (SO) levels on growth performance, lipid deposition, tissues fatty acid compositions and hepatic lipid metabolism related gene expressions in blunt snout bream (M. amblycephala). Fish (average weight 0.34±0.01g) were fed five experimental diets containing the following inclusion levels of SO: 0% (0%SO), 20% (20%SO), 32% (32%SO), 56% (56%SO) and 100% (100%SO) in dietary lipid, and a diet contained 100% fish oil (100%FO) was also used here. The percentages of 18:2n−6 in the liver and muscle significantly increased with increasing dietary SO level, and the fish fed 56%SO and 100%SO diets significantly increased 20:4n−6 contents in the liver and muscle, suggesting blunt snout bream has the capacity to convert C18 fatty acids (PUFAs) to C20/22 fatty acids. However, increasing dietary SO level up-regulated acyl-CoA delta-9 desaturase and down-regulated peroxisome proliferator-activated receptors-α and -β, which might be related associated with high level of 18:2n−6 in SO. It suggested that supplementation of 20% soybean oil (8% lipid in diet) could improve growth of blunt snout bream juvenile. However, an excess of 18:2n−6 in SO would modify the expressions of lipid metabolism-related genes, which induced lipid deposition in fish.

Fucoxanthin Enhances Chain Elongation and Desaturation of Alpha-Linolenic Acid in HepG2 Cells.

Dietary fucoxanthin (FX), a carotenoid compound from brown algae, was found to increase docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) in the liver of mice. DHA and ARA are known to be biosynthesized from the respective precursor α-linolenic acid (ALA, 18:3n-3) and linoleic acid (LNA, 18:2n-6), through desaturation and chain elongation. We examined the effect of FX on the fatty acid metabolism in HepG2 cells (Hepatocellular carcinoma, human). In the first experiment, cells were co-treated with ALA (100 μM) and FX (0-100 μM) or vehicle for 48 h. FX increased eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3), DHA at concentrations of ≥ 50 μM. To clarify the change in the metabolism of polyunsaturated fatty acid (PUFA), in the second experiment, cells were co-treated with universally-[(13)C]-labeled (U-[(13)C]-) ALA (100 μM) and FX (100 μM) for 0.5, 3, 6, 24 and 48 h. [(13)C] labeled-EPA, DPA and DHA content in HepG2 cells were all increased by FX after 48 h treatment. Furthermore, estimated delta-5 desaturase (D5D) but not delta-6 desaturase (D6D) activity index was increased at 48 h. These results suggested that FX may enhance the conversion of ALA to longer chain n-3 PUFA through increasing D5D activity in the liver.

Design, synthesis, and in vivo activity of novel inhibitors of delta-5 desaturase for the treatment of metabolic syndrome.

The synthesis, SAR, and in vivo activity of inhibitors of delta-5 desaturase are described. Ring-constraint of the initial series provided access to a variety of in vitro active chemotypes, from which the indazole was selected. Examples from the indazole series displayed in vivo activity in reducing the enzymatic activity of liver delta-5 desaturase.

Transcriptional Responses Associated with Virulence and Defence in the Interaction between Heterobasidion annosum s.s. and Norway Spruce.

Heterobasidion annosum sensu lato is a serious pathogen causing root and stem rot to conifers in the northern hemisphere and rendering the timber defective for sawing and pulping. In this study we applied next-generation sequencing to i) identify transcriptional responses unique to Heterobasidion-inoculated Norway spruce and ii) investigate the H. annosum transcripts to identify putative virulence factors. To address these objectives we wounded or inoculated 30-year-old Norway spruce clones with H. annosum and 454-sequenced the transcriptome of the interaction at 0, 5 and 15 days post inoculation. The 491860 high-quality reads were de novo assembled and the relative expression was analysed. Overall, very few H. annosum transcripts were represented in our dataset. Three delta-12 fatty acid desaturase transcripts and one Clavaminate synthase-like transcript, both associated with virulence in other pathosystems, were found among the significantly induced transcripts. The analysis of the Norway spruce transcriptional responses produced a handful of differentially expressed transcripts. Most of these transcripts originated from genes known to respond to H. annosum. However, three genes that had not previously been reported to respond to H. annosum showed specific induction to inoculation: an oxophytodienoic acid–reductase (OPR), a beta–glucosidase and a germin-like protein (GLP2) gene. Even in a small data set like ours, five novel highly expressed Norway spruce transcripts without significant alignment to any previously annotated protein in Genbank but present in the P. abies (v1.0) gene catalogue were identified. Their expression pattern suggests a role in defence. Therefore a more complete survey of the transcriptional responses in the interactions between Norway spruce and its major pathogen H. annosum would probably provide a better understanding of gymnosperm defence than accumulated until now.

Global lipidomics profiling of cotton seed oil genotypes using CO2-based chromatography coupled to mass spectrometry

Refined cottonseed oil enjoys widespread applications in the food and chemical industries. Although the major lipids comprising cottonseed oil are well known, there are many diverse lipid species in cotton seeds that occur at much lower levels and have important nutritional or anti-nutritional properties. Lipidomics analysis of complex lipids in seed oil extracts using a single chromatographic technique is challenging due to the diversity of lipid polarity and the large range of concentrations of lipid species in biological samples. Ultra Performance Convergence Chromatography (UPC2) is a chromatographic system that utilizes liquid CO2 as primary solvent and co-solvents such as methanol as a mobile phase to leverage the chromatographic principles and selectivity of normal phase chromatography while providing the ease-of-use of reversed-phase LC. We have used UPC2 coupled to mass spectrometry for the separation of free fatty acids, neutral and polar lipids in a single cotton seed lipid extract. Several seed oil genotypes, including high oleic acid line of Gossypium hirsutum cv. Coker 312 with a nonfunctional Brassica napus allele of delta-12 fatty acid desaturase (FAD2) and naturally occurring high oleic acid line of G. barbadense, were profiled to identify global consequences of modulating seed oil fatty acid composition. Potential markers that discriminate the different genotypes were identified and quantified.

Cloning and molecular characterization of a delta-6 fatty acid desaturase gene from Isochrysis sp. CCMM5001

The cDNA of the delta-6 (Delta 6) fatty acid desaturase gene IsFAD6 was isolated from the marine microalga Isochrysis sp. CCMM5001. Sequence analysis indicated that the total length of IsFAD6 is 2767 bp, and the gene contains a 1407-bp open reading frame, a 406-bp 5' untranslated region (UTR), and a 954-bp 3' UTR with a typical polyA tail. The gene encodes a protein with 469 amino acids, with a molecular weight of 52.9 kDa and an isoelectric point of 8.6. IsFAD6 contains three conserved histidine motifs and a cytochrome b5 domain. Real-time PCR analysis showed that the expression levels of IsFAD6 were significantly upregulated under diverse abiotic stresses, including low temperature (15 and 25 A degrees C), high salinity (62aEuro degrees), and high nitrogen deficiency (220 mu mol L-1 sodium nitrate), compared with those under control conditions (20 A degrees C, 31aEuro degrees salinity, and 880 mu mol L-1 sodium nitrate in the f/2 medium). The IsFAD6 transcript levels minimally increased under high salinity (93aEuro degrees) and excess sodium nitrate (1760 mu mol L-1). Our findings provided an understanding of IsFAD6 responses to temperature, salinity, and nitrate stresses at the transcriptional level. These results indicated that IsFAD6 cloned from Isochrysis sp. CCMM5001 is involved in acclimation to temperature, salt, and nitrogen stresses. The heterologous expression of IsFAD6 in Saccharomyces cerevisiae futher indicated that IsFAD6 could utilize endogenous substrates to synthesize gamma-linolenic acid (18:3(Delta 6,9,12)) and stearidonic acid (18:4(Delta 6,9,12,15)), which are involved in acclimation to adverse conditions.