Can polymorphisms in the fatty acid desaturase (FADS) gene cluster alter the effects of fish oil supplementation on plasma and erythrocyte fatty acid profiles? An exploratory study.

PubMed

Meldrum, Suzanne J; Li, Yuchun; Zhang, Guicheng; Heaton, Alexandra E M; D'Vaz, Nina; Manz, Judith; Reischl, Eva; Koletzko, Berthold V; Prescott, Susan L; Simmer, Karen

2017-09-19

The enzymes encoded by fatty acid desaturases (FADS) genes determine the desaturation of long-chain polyunsaturated fatty acids (LCPUFA). We investigated if haplotype and single nucleotide polymorphisms (SNPs) in FADS gene cluster can influence LCPUFA status in infants who received either fish oil or placebo supplementation. Children enrolled in the Infant Fish Oil Supplementation Study (IFOS) were randomly allocated to receive either fish oil or placebo from birth to 6 months of age. Blood was collected at 6 months of age for the measurement of fatty acids and for DNA extraction. A total of 276 participant DNA samples underwent genotyping, and 126 erythrocyte and 133 plasma fatty acid measurements were available for analysis. Twenty-two FADS SNPs were selected on the basis of literature and linkage disequilibrium patterns identified from the HapMap data. Haplotype construction was completed using PHASE. For participants allocated to the fish oil group who had two copies of the FADS1 haplotype consisting of SNP minor alleles, DHA levels were significantly higher compared to other haplotypes. This finding was not observed for the placebo group. Furthermore, for members of the fish oil group only, the minor homozygous carriers of all the FADS1 SNPs investigated had significantly higher DHA than other genotypes (rs174545, rs174546, rs174548, rs174553, rs174556, rs174537, rs174448, and rs174455). Overall results of this preliminary study suggest that supplementation with fish oil may only significantly increase DHA in minor allele carriers of FADS1 SNPs. Further research is required to confirm this novel finding.

Fatty acid desaturase gene variants, cardiovascular risk factors, and myocardial infarction in the costa rica study

USDA-ARS?s Scientific Manuscript database

Genetic variation in fatty acid desaturases (FADS) has previously been linked to long-chain polyunsaturated fatty acids (PUFAs) in adipose tissue and cardiovascular risk. The goal of our study was to test associations between six common FADS polymorphisms (rs174556, rs3834458, rs174570, rs2524299, r...

Umbilical cord PUFA are determined by maternal and child fatty acid desaturase (FADS) genetic variants in the Avon Longitudinal Study of Parents and Children (ALSPAC)

PubMed Central

Lattka, Eva; Koletzko, Berthold; Zeilinger, Sonja; Hibbeln, Joseph R.; Klopp, Norman; Ring, Susan M.; Steer, Colin D.

2012-01-01

Fetal supply with long-chain PUFA (LC-PUFA) during pregnancy is important for brain growth and visual and cognitive development and is provided by materno–fetal placental transfer. We recently showed that maternal fatty acid desaturase (FADS) genotypes modulate the amounts of LC-PUFA in maternal blood. Whether FADS genotypes influence the amounts of umbilical cord fatty acids has not been investigated until now. The aim of the present study was to investigate the influence of maternal and child FADS genotypes on the amounts of LC-PUFA in umbilical cord venous plasma as an indicator of fetal fatty acid supply during pregnancy. A total of eleven cord plasma n-6 and n-3 fatty acids were analysed for association with seventeen FADS gene cluster SNP in over 2000 mothers and children from the Avon Longitudinal Study of Parents and Children. In a multivariable analysis, the maternal genotype effect was adjusted for the child genotype and vice versa to estimate which of the two has the stronger influence on cord plasma fatty acids. Both maternal and child FADS genotypes and haplotypes influenced amounts of cord plasma LC-PUFA and fatty acid ratios. Specifically, most analysed maternal SNP were associated with cord plasma levels of the precursor n-6 PUFA, whereas the child genotypes were mainly associated with more highly desaturated n-6 LC-PUFA. This first study on FADS genotypes and cord fatty acids suggests that fetal LC-PUFA status is determined to some extent by fetal fatty acid conversion. Associations of particular haplotypes suggest specific effects of SNP rs498793 and rs968567 on fatty acid metabolism. PMID:22877655

Umbilical cord PUFA are determined by maternal and child fatty acid desaturase (FADS) genetic variants in the Avon Longitudinal Study of Parents and Children (ALSPAC).

PubMed

Lattka, Eva; Koletzko, Berthold; Zeilinger, Sonja; Hibbeln, Joseph R; Klopp, Norman; Ring, Susan M; Steer, Colin D

2013-04-14

Fetal supply with long-chain PUFA (LC-PUFA) during pregnancy is important for brain growth and visual and cognitive development and is provided by materno-fetal placental transfer. We recently showed that maternal fatty acid desaturase (FADS) genotypes modulate the amounts of LC-PUFA in maternal blood. Whether FADS genotypes influence the amounts of umbilical cord fatty acids has not been investigated until now. The aim of the present study was to investigate the influence of maternal and child FADS genotypes on the amounts of LC-PUFA in umbilical cord venous plasma as an indicator of fetal fatty acid supply during pregnancy. A total of eleven cord plasma n-6 and n-3 fatty acids were analysed for association with seventeen FADS gene cluster SNP in over 2000 mothers and children from the Avon Longitudinal Study of Parents and Children. In a multivariable analysis, the maternal genotype effect was adjusted for the child genotype and vice versa to estimate which of the two has the stronger influence on cord plasma fatty acids. Both maternal and child FADS genotypes and haplotypes influenced amounts of cord plasma LC-PUFA and fatty acid ratios. Specifically, most analysed maternal SNP were associated with cord plasma levels of the precursor n-6 PUFA, whereas the child genotypes were mainly associated with more highly desaturated n-6 LC-PUFA. This first study on FADS genotypes and cord fatty acids suggests that fetal LC-PUFA status is determined to some extent by fetal fatty acid conversion. Associations of particular haplotypes suggest specific effects of SNP rs498793 and rs968567 on fatty acid metabolism.

Gene Expression of Desaturase (FADS1 and FADS2) and Elongase (ELOVL5) Enzymes in Peripheral Blood: Association with Polyunsaturated Fatty Acid Levels and Atopic Eczema in 4-Year-Old Children

PubMed Central

Chisaguano, Aida Maribel; Montes, Rosa; Pérez-Berezo, Teresa; Castellote, Ana Isabel; Guerendiain, Marcela; Bustamante, Mariona; Morales, Eva; García-Esteban, Raquel; Sunyer, Jordi; Franch, Àngels; López-Sabater, M. Carmen

2013-01-01

Abstract Background It is unknown if changes in the gene expression of the desaturase and elongase enzymes are associated with abnormal n-6 long chain polyunsaturated fatty acid (LC-PUFA) levels in children with atopic eczema (AE). We analyzed whether mRNA-expression of genes encoding key enzymes of LC-PUFA synthesis (FADS1, FADS2 and ELOVL5) is associated with circulating LC-PUFA levels and risk of AE in 4-year-old children. Methods AE (n=20) and non-AE (n=104) children participating in the Sabadell cohort within the INfancia y Medio Ambiente (INMA) Project were included in the present study. RT-PCR with TaqMan Low-Density Array cards was used to measure the mRNA-expression of FADS1, FADS2 and ELOVL5. LC-PUFA levels were measured by fast gas chromatography in plasma phospholipids. The relationship of gene expression with LC-PUFA levels and enzyme activities was evaluated by Pearson’s rank correlation coefficient, and logistic regression models were used to study its association with risk of developing AE. Results Children with AE had lower levels of several n-6 PUFA members, dihomo-γ-linolenic (DGLA) and arachidonic (AA) acids. mRNA-expression levels of FADS1 and 2 strongly correlated with DGLA levels and with D6D activity. FADS2 and ELOVL5 mRNA-expression levels were significantly lower in AE than in non-AE children (-40.30% and -20.36%; respectively), but no differences were found for FADS1. Conclusions and Significance Changes in the mRNA-expression levels of FADS1 and 2 directly affect blood DGLA levels and D6D activity. This study suggests that lower mRNA-expressions of FADS2 and ELOVL5 are associated with higher risk of atopic eczema in young children. PMID:24167612

Gene expression of desaturase (FADS1 and FADS2) and Elongase (ELOVL5) enzymes in peripheral blood: association with polyunsaturated fatty acid levels and atopic eczema in 4-year-old children.

PubMed

Chisaguano, Aida Maribel; Montes, Rosa; Pérez-Berezo, Teresa; Castellote, Ana Isabel; Guerendiain, Marcela; Bustamante, Mariona; Morales, Eva; García-Esteban, Raquel; Sunyer, Jordi; Franch, Angels; López-Sabater, M Carmen

2013-01-01

It is unknown if changes in the gene expression of the desaturase and elongase enzymes are associated with abnormal n-6 long chain polyunsaturated fatty acid (LC-PUFA) levels in children with atopic eczema (AE). We analyzed whether mRNA-expression of genes encoding key enzymes of LC-PUFA synthesis (FADS1, FADS2 and ELOVL5) is associated with circulating LC-PUFA levels and risk of AE in 4-year-old children. AE (n=20) and non-AE (n=104) children participating in the Sabadell cohort within the INfancia y Medio Ambiente (INMA) Project were included in the present study. RT-PCR with TaqMan Low-Density Array cards was used to measure the mRNA-expression of FADS1, FADS2 and ELOVL5. LC-PUFA levels were measured by fast gas chromatography in plasma phospholipids. The relationship of gene expression with LC-PUFA levels and enzyme activities was evaluated by Pearson's rank correlation coefficient, and logistic regression models were used to study its association with risk of developing AE. Children with AE had lower levels of several n-6 PUFA members, dihomo-γ-linolenic (DGLA) and arachidonic (AA) acids. mRNA-expression levels of FADS1 and 2 strongly correlated with DGLA levels and with D6D activity. FADS2 and ELOVL5 mRNA-expression levels were significantly lower in AE than in non-AE children (-40.30% and -20.36%; respectively), but no differences were found for FADS1. Changes in the mRNA-expression levels of FADS1 and 2 directly affect blood DGLA levels and D6D activity. This study suggests that lower mRNA-expressions of FADS2 and ELOVL5 are associated with higher risk of atopic eczema in young children.

DNA methylation in an enhancer region of the FADS cluster is associated with FADS activity in human liver.

PubMed

Howard, Timothy D; Mathias, Rasika A; Seeds, Michael C; Herrington, David M; Hixson, James E; Shimmin, Lawrence C; Hawkins, Greg A; Sellers, Matthew; Ainsworth, Hannah C; Sergeant, Susan; Miller, Leslie R; Chilton, Floyd H

2014-01-01

Levels of omega-6 (n-6) and omega-3 (n-3), long chain polyunsaturated fatty acids (LcPUFAs) such as arachidonic acid (AA; 20:4, n-6), eicosapentaenoic acid (EPA; 20:5, n-3) and docosahexaenoic acid (DHA; 22:6, n-3) impact a wide range of biological activities, including immune signaling, inflammation, and brain development and function. Two desaturase steps (Δ6, encoded by FADS2 and Δ5, encoded by FADS1) are rate limiting in the conversion of dietary essential 18 carbon PUFAs (18C-PUFAs) such as LA (18:2, n-6) to AA and α-linolenic acid (ALA, 18:3, n-3) to EPA and DHA. GWAS and candidate gene studies have consistently identified genetic variants within FADS1 and FADS2 as determinants of desaturase efficiencies and levels of LcPUFAs in circulating, cellular and breast milk lipids. Importantly, these same variants are documented determinants of important cardiovascular disease risk factors (total, LDL, and HDL cholesterol, triglycerides, CRP and proinflammatory eicosanoids). FADS1 and FADS2 lie head-to-head (5' to 5') in a cluster configuration on chromosome 11 (11q12.2). There is considerable linkage disequilibrium (LD) in this region, where multiple SNPs display association with LcPUFA levels. For instance, rs174537, located ∼ 15 kb downstream of FADS1, is associated with both FADS1 desaturase activity and with circulating AA levels (p-value for AA levels = 5.95 × 10(-46)) in humans. To determine if DNA methylation variation impacts FADS activities, we performed genome-wide allele-specific methylation (ASM) with rs174537 in 144 human liver samples. This approach identified highly significant ASM with CpG sites between FADS1 and FADS2 in a putative enhancer signature region, leading to the hypothesis that the phenotypic associations of rs174537 are likely due to methylation differences. In support of this hypothesis, methylation levels of the most significant probe were strongly associated with FADS1 and, to a lesser degree, FADS2 activities.

Differences in Arachidonic Acid Levels and Fatty Acid Desaturase (FADS) Gene Variants in African Americans and European Americans with Diabetes/Metabolic Syndrome

PubMed Central

Sergeant, Susan; Hugenschmidt, Christina E.; Rudock, Megan E.; Ziegler, Julie T.; Ivester, Priscilla; Ainsworth, Hannah C.; Vaidya, Dhananjay; Case, L. Douglas; Langefeld, Carl D.; Freedman, Barry I.; Bowden, Donald W.; Mathias, Rasika A.; Chilton, Floyd H.

2012-01-01

Over the past 50 years, increases in dietary n-6 polyunsaturated fatty acids (PUFAs), such as linoleic acid, have been hypothesized to cause or exacerbate chronic inflammatory diseases. This study examines an individual’s innate capacity to synthesize n-6-long chain PUFAs (LC-PUFAs), with respect to the fatty acid desaturase (FADS) locus in Americans of African and European descent with diabetes/metabolic syndrome. Compared to European Americans (EAm), African Americans (AfAm) exhibited markedly higher serum levels of arachidonic acid (AA) (EAm 7.9±2.1; AfAm 9.8±1.9 % of total fatty acids, mean ± sd; p<2.29×10−9) and the AA to n-6-precursor fatty acid ratio, which estimates FADS1 activity (EAm 5.4±2.2, AfAm 6.9±2.2; p=1.44×10−5). Seven single nucleotide polymorphisms (SNP) mapping to the FADS locus revealed strong association with AA, eicosapentaenoic acid (EPA) and dihomogamma-linolenic acid (DGLA) in the EAm. Importantly, EAm homozygous for the minor allele (T) had significantly lower AA levels (TT: 6.3±1.0; GG: 8.5±2.1; p=3.0×10−5) and AA/DGLA ratios (TT: 3.4±0.8; GG: 6.5±2.3; p=2.2×10−7) but higher DGLA levels (TT: 1.9±0.4; GG: 1.4±0.4; p=3.3×10−7) compared to those homozygous for the major allele (GG). Allele frequency patterns suggest that the GG genotype at rs174537 (associated with higher circulating levels of AA) is much higher in AfAm (0.81) compared to EAm (0.46). Similarly, marked differences in rs174537 genotypic frequencies were observed in HapMap populations. These data suggest that there are likely important differences in the capacity of different populations to synthesize LC-PUFAs. These differences may provide a genetic mechanism contributing to health disparities between populations of African and European descent. PMID:21733300

TEMPERATURE-SENSITIVE, POST-TRANSLATIONAL REGULATION OF PLANT OMEGA-3 FATTY ACID DESATURASES IS MEDIATED BY THE ER-ASSOCIATED DEGRADATION PATHWAY

USDA-ARS?s Scientific Manuscript database

In plants, the endoplasmic reticulum (ER)-localized omega-3 fatty acid desaturases (Fad3s) increase the production of polyunsaturated fatty acids at cooler temperatures, but the FAD3 genes themselves are typically not upregulated during this adaptive response. Here, we expressed two closely related ...

Association of polyunsaturated fatty acids in breast milk with fatty acid desaturase gene polymorphisms among Chinese lactating mothers.

PubMed

Ding, Zhen; Liu, Guo-Liang; Li, Xiang; Chen, Xue-Yan; Wu, Yi-Xia; Cui, Can-Can; Zhang, Xi; Yang, Guang; Xie, Lin

2016-06-01

The fatty acid desaturase (FADS) controls polyunsaturated fatty acid (PUFA) synthesis in human tissues and breast milk. Evaluate the influence of 10 single nucleotide polymorphisms (SNPs) and various haplotypes in the FADS gene cluster (FADS1, FADS2, FADS3) on PUFA concentration in the breast milk of 209 healthy Chinese women. PUFA concentrations were measured in breast milk using gas chromatography and genotyping was performed using the Sequenom Mass Array system. A SNP (rs1535) and 2-locus haplotypes (rs3834458-rs1535, rs1535-rs174575) in the FADS2 gene were associated with concentrations of γ-linoleic acid (GLA) and arachidonic acid (AA) in breast milk. Likewise, in the FADS1 gene, a 2-locus constructed haplotype (rs174547-rs174553) also affected GLA and AA concentration (P<0.05 for all). Minor allele carriers of the SNP and haplotypes described above had lower concentrations of GLA and AA. In the FADS2 gene, the 3-locus haplotype rs3834458-rs1535-rs174575, significantly affected concentrations of GLA but not AA. Pairwise comparison showed that individuals major homozygous for the SNP rs1000778 in the FADS3 gene had lower concentrations of ALA and linoleic acid (LA) in their breast milk. Polymorphisms in the FADS gene cluster influence PUFA concentrations in the breast milk of Chinese Han lactating women. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fatty acid desaturase 1 knockout mice are lean with improved glycemic control and decreased development of atheromatous plaque

PubMed Central

Powell, David R; Gay, Jason P; Smith, Melinda; Wilganowski, Nathaniel; Harris, Angela; Holland, Autumn; Reyes, Maricela; Kirkham, Laura; Kirkpatrick, Laura L; Zambrowicz, Brian; Hansen, Gwenn; Platt, Kenneth A; van Sligtenhorst, Isaac; Ding, Zhi-Ming; Desai, Urvi

2016-01-01

Delta-5 desaturase (D5D) and delta-6 desaturase (D6D), encoded by fatty acid desaturase 1 (FADS1) and FADS2 genes, respectively, are enzymes in the synthetic pathways for ω3, ω6, and ω9 polyunsaturated fatty acids (PUFAs). Although PUFAs appear to be involved in mammalian metabolic pathways, the physiologic effect of isolated D5D deficiency on these pathways is unclear. After generating >4,650 knockouts (KOs) of independent mouse genes and analyzing them in our high-throughput phenotypic screen, we found that Fads1 KO mice were among the leanest of 3,651 chow-fed KO lines analyzed for body composition and were among the most glucose tolerant of 2,489 high-fat-diet-fed KO lines analyzed by oral glucose tolerance test. In confirmatory studies, chow- or high-fat-diet-fed Fads1 KO mice were leaner than wild-type (WT) littermates; when data from multiple cohorts of adult mice were combined, body fat was 38% and 31% lower in Fads1 male and female KO mice, respectively. Fads1 KO mice also had lower glucose and insulin excursions during oral glucose tolerance tests along with lower fasting glucose, insulin, triglyceride, and total cholesterol levels. In additional studies using a vascular injury model, Fads1 KO mice had significantly decreased femoral artery intima/media ratios consistent with a decreased inflammatory response in their arterial wall. Based on this result, we bred Fads1 KO and WT mice onto an ApoE KO background and fed them a Western diet for 14 weeks; in this atherogenic environment, aortic trees of Fads1 KO mice had 40% less atheromatous plaque compared to WT littermates. Importantly, PUFA levels measured in brain and liver phospholipid fractions of Fads1 KO mice were consistent with decreased D5D activity and normal D6D activity. The beneficial metabolic phenotype demonstrated in Fads1 KO mice suggests that selective D5D inhibitors may be useful in the treatment of human obesity, diabetes, and atherosclerotic cardiovascular disease. PMID:27382320

Biosynthesis of Polyunsaturated Fatty Acids in the Razor Clam Sinonovacula constricta: Characterization of Δ5 and Δ6 Fatty Acid Desaturases.

PubMed

Ran, Zhaoshou; Xu, Jilin; Liao, Kai; Li, Shuang; Chen, Shubing; Yan, Xiaojun

2018-05-09

To investigate the endogenous long-chain polyunsaturated fatty acid (LC-PUFA) biosynthetic ability in Sinonovacula constricta, fatty acid desaturases (Fads) of this bivalve, namely, Scfad5a, Scfad5b, and Scfad6, were cloned and characterized in the current study. Meanwhile, the tissue distributions of S. constricta Fads and fatty acids (FAs) were examined. Heterologous expression in yeasts confirmed that Scfad5a and Scfad5b were both Δ5 Fads, while Scfad6 was a Δ6 Fad. However, compared with Fads in other organisms, the desaturation activities of S. constricta Fads were relatively low (especially for Scfad6), indicating an adaptation to living conditions. S. constricta Fads were expressed in all tissues examined, and particularly high expressions were found in intestine and gonad. Moreover, FAs were differently distributed among tissues, which might be correlated with their corresponding physiological roles. Taken together, the results provided an insight into LC-PUFA biosynthesis in S. constricta. Notably, Scfad6 was the first functionally characterized Δ6 Fad in marine molluscs to date.

Associations between variants of FADS genes and omega-3 and omega-6 milk fatty acids of Canadian Holstein cows.

PubMed

Ibeagha-Awemu, Eveline M; Akwanji, Kingsley A; Beaudoin, Frédéric; Zhao, Xin

2014-02-17

Fatty acid desaturase 1 (FADS1) and 2 (FADS2) genes code respectively for the enzymes delta-5 and delta-6 desaturases which are rate limiting enzymes in the synthesis of polyunsaturated omega-3 and omega-6 fatty acids (FAs). Omega-3 and-6 FAs as well as conjugated linoleic acid (CLA) are present in bovine milk and have demonstrated positive health effects in humans. Studies in humans have shown significant relationships between genetic variants in FADS1 and 2 genes with plasma and tissue concentrations of omega-3 and-6 FAs. The aim of this study was to evaluate the extent of sequence variations within these two genes in Canadian Holstein cows as well as the association between sequence variants and health promoting FAs in milk. Thirty three SNPs were detected within the studied regions of genes including a synonymous mutation (FADS1-07, rs42187261, 306Tyr > Tyr) in exon 8 of FADS1, a non-synonymous mutation (FADS2-14, rs211580559, 294Ala > Val) within FADS2 exon 7, a splice site SNP (FADS2-05, rs211263660), a 3'UTR SNP (FADS2-23, rs109772589), and another 3'UTR SNP with an effect on a microRNA binding site within FADS2 gene (FADS2-19, rs210169303). Association analyses showed significant relations between three out of seven tested SNPs and several FAs. Significant associations (FDR P < 0.05) were recorded between FADS2-23 (rs109772589) and two omega-6 FAs (dihomogamma linolenic acid [C20:3n6] and arachidonic acid [C20:4n6]), FADS1-07 (rs42187261) and one omega-3 FA (eicosapentaenoic acid, C20:5n3) and tricosanoic acid (C23:0), and one intronic SNP, FADS1-01 (rs136261927) and C20:3n6. Our study has demonstrated positive associations between three SNPs within FADS1 and FADS2 genes (a SNP within the 3'UTR, a synonymous SNP and an intronic SNP), with three milk PUFAs of Canadian Holstein cows thus suggesting possible involvement of synonymous and non-coding region variants in FA synthesis. These SNPs may serve as potential genetic markers in breeding programs to

Molecular cloning and functional analysis of two FAD2 genes from American grape (Vitis labrusca L.).

PubMed

Lee, Kyeong-Ryeol; Kim, Sun Hee; Go, Young-Sam; Jung, Sung Min; Roh, Kyung Hee; Kim, Jong-Bum; Suh, Mi-Chung; Lee, Sukchan; Kim, Hyun Uk

2012-11-10

The synthesis of polyunsaturated fatty acids (PUFAs), the most abundant fatty acids in plants, begins with a reaction catalyzed by fatty acid desaturase 2 (FAD2; EC 1.3.1.35), also called microsomal oleate Δ12-desaturase. Since the FAD2 gene was first identified in Arabidopsis thaliana, FAD2 research has gained wide interest as the essential enzyme for synthesizing PUFA. Grapes are one of the most frequently cultivated fruits in the world, with most commercial growers cultivating Vitis vinifera and V. labrusca. Grapeseed oil contains a high proportion, 60-70% of linoleic acid (18:2). We cloned two putative FAD2 genes from V. labrusca cv. Campbell Early based on V. vinifera genome sequences. Deduced amino acid sequences of two putative genes showed that VlFAD2s show high similarity to Arabidopsis FAD2 and commonly contain six transmembrane domain, three histidine boxes and endoplasmic reticulum (ER) retrieval motif representing the characteristics of fatty acid desaturase. Phylogenetic analyses of various plant FAD2s showed that VlFAD2-1 and VlFAD2-2 are separately grouped with constitutive and seed-type FAD2s, respectively. Southern blot showed that one or two bands are found in each lane. Because Campbell Early is a hybrid cultivar, FAD2-1 and FAD2-2 genes may exist as one copy in V. labrusca. Expression analysis in different tissues indicated that VlFAD2-1 is a constitutive gene but VlFAD2-2 is a seed-type gene. Complementation experiments of fad2-1 mutant Arabidopsis with VlFAD2-1 or VlFAD2-2 demonstrated that VlFAD2-1 and VlFAD2-2 can restore low PUFA proportion of fad2 to normal PUFA proportion. Copyright © 2012 Elsevier B.V. All rights reserved.

Molecular and functional characterization of a fads2 orthologue in the Amazonian teleost, Arapaima gigas.

PubMed

Lopes-Marques, Mónica; Ozório, Rodrigo; Amaral, Ricardo; Tocher, Douglas R; Monroig, Óscar; Castro, L Filipe C

2017-01-01

The Brazilian teleost Arapaima gigas is an iconic species of the Amazon. In recent years a significant effort has been put into the farming of arapaima to mitigate overfishing threats. However, little is known regarding the nutritional requirements of A. gigas in particular those for essential fatty acids including the long-chain polyunsaturated fatty acids (LC-PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The ability to biosynthesize LC-PUFA is dependent upon the gene repertoire of fatty acyl desaturases (Fads) and elongases (Elovl), as well as their fatty acid specificities. In the present study we characterized both molecularly and functionally an orthologue of the desaturase fatty acid desaturase 2 (fads2) from A. gigas. The isolated sequence displayed the typical desaturase features, a cytochrome b 5 -domain with the heme-binding motif, two transmembrane domains and three histidine-rich regions. Functional characterization of A. gigas fads2 showed that, similar to other teleosts, the A. gigas fads2 exhibited a predominant Δ6 activity complemented with some capacity for Δ8 desaturation. Given that A. gigas belongs to one of the oldest teleostei lineages, the Osteoglossomorpha, these findings offer a significant insight into the evolution LC-PUFA biosynthesis in teleosts. Copyright © 2016 Elsevier Inc. All rights reserved.

Desaturase and elongase-limiting endogenous long-chain polyunsaturated fatty acid biosynthesis.

PubMed

Zhang, Ji Yao; Kothapalli, Kumar S D; Brenna, J Thomas

2016-03-01

Endogenous synthesis of the long-chain polyunsaturated fatty acids (LCPUFAs) is mediated by the fatty acid desaturase (FADS) gene cluster (11q12-13.1) and elongation of very long-chain fatty acids 2 (ELOVL2) (6p24.2) and ELOVL5 (6p12.1). Although older biochemical work identified the product of one gene, FADS2, rate limiting for LCPUFA synthesis, recent studies suggest that polymorphisms in any of these genes can limit accumulation of product LCPUFA. Genome-wide association study (GWAS) of Greenland Inuit shows strong adaptation signals within FADS gene cluster, attributed to high omega-3 fatty acid intake, while GWAS found ELOVL2 associated with sleep duration, age and DNA methylation. ELOVL5 coding mutations cause spinocerebellar ataxia 38, and epigenetic marks were associated with depression and suicide risk. Two sterol response element binding sites were found on ELOVL5, a SREBP-1c target gene. Minor allele carriers of a 3 single nucleotide polymorphism (SNP) haplotype in ELOVL2 have decreased 22 : 6n-3 levels. Unequivocal molecular evidence shows mammalian FADS2 catalyzes direct Δ4-desaturation to yield 22 : 6n-3 and 22 : 5n-6. An SNP near FADS1 influences the levels of 5-lipoxygenase products and epigenetic alteration. Genetic polymorphisms within FADS and ELOVL can limit LCPUFA product accumulation at any step of the biosynthetic pathway.

Associations between variants of FADS genes and omega-3 and omega-6 milk fatty acids of Canadian Holstein cows

PubMed Central

2014-01-01

Background Fatty acid desaturase 1 (FADS1) and 2 (FADS2) genes code respectively for the enzymes delta-5 and delta-6 desaturases which are rate limiting enzymes in the synthesis of polyunsaturated omega-3 and omega-6 fatty acids (FAs). Omega-3 and-6 FAs as well as conjugated linoleic acid (CLA) are present in bovine milk and have demonstrated positive health effects in humans. Studies in humans have shown significant relationships between genetic variants in FADS1 and 2 genes with plasma and tissue concentrations of omega-3 and-6 FAs. The aim of this study was to evaluate the extent of sequence variations within these two genes in Canadian Holstein cows as well as the association between sequence variants and health promoting FAs in milk. Results Thirty three SNPs were detected within the studied regions of genes including a synonymous mutation (FADS1-07, rs42187261, 306Tyr > Tyr) in exon 8 of FADS1, a non-synonymous mutation (FADS2-14, rs211580559, 294Ala > Val) within FADS2 exon 7, a splice site SNP (FADS2-05, rs211263660), a 3′UTR SNP (FADS2-23, rs109772589), and another 3′UTR SNP with an effect on a microRNA binding site within FADS2 gene (FADS2-19, rs210169303). Association analyses showed significant relations between three out of seven tested SNPs and several FAs. Significant associations (FDR P < 0.05) were recorded between FADS2-23 (rs109772589) and two omega-6 FAs (dihomogamma linolenic acid [C20:3n6] and arachidonic acid [C20:4n6]), FADS1-07 (rs42187261) and one omega-3 FA (eicosapentaenoic acid, C20:5n3) and tricosanoic acid (C23:0), and one intronic SNP, FADS1-01 (rs136261927) and C20:3n6. Conclusion Our study has demonstrated positive associations between three SNPs within FADS1 and FADS2 genes (a SNP within the 3’UTR, a synonymous SNP and an intronic SNP), with three milk PUFAs of Canadian Holstein cows thus suggesting possible involvement of synonymous and non-coding region variants in FA synthesis. These SNPs may serve as

Diversity of Δ12 Fatty Acid Desaturases in Santalaceae and Their Role in Production of Seed Oil Acetylenic Fatty Acids*

PubMed Central

Okada, Shoko; Zhou, Xue-Rong; Damcevski, Katherine; Gibb, Nerida; Wood, Craig; Hamberg, Mats; Haritos, Victoria S.

2013-01-01

Plants in the Santalaceae family, including the native cherry Exocarpos cupressiformis and sweet quandong Santalum acuminatum, accumulate ximenynic acid (trans-11-octadecen-9-ynoic acid) in their seed oil and conjugated polyacetylenic fatty acids in root tissue. Twelve full-length genes coding for microsomal Δ12 fatty acid desaturases (FADs) from the two Santalaceae species were identified by degenerate PCR. Phylogenetic analysis of the predicted amino acid sequences placed five Santalaceae FADs with Δ12 FADs, which include Arabidopsis thaliana FAD2. When expressed in yeast, the major activity of these genes was Δ12 desaturation of oleic acid, but unusual activities were also observed: i.e. Δ15 desaturation of linoleic acid as well as trans-Δ12 and trans-Δ11 desaturations of stearolic acid (9-octadecynoic acid). The trans-12-octadecen-9-ynoic acid product was also detected in quandong seed oil. The two other FAD groups (FADX and FADY) were present in both species; in a phylogenetic tree of microsomal FAD enzymes, FADX and FADY formed a unique clade, suggesting that are highly divergent. The FADX group enzymes had no detectable Δ12 FAD activity but instead catalyzed cis-Δ13 desaturation of stearolic acid when expressed in yeast. No products were detected for the FADY group when expressed recombinantly. Quantitative PCR analysis showed that the FADY genes were expressed in leaf rather than developing seed of the native cherry. FADs with promiscuous and unique activities have been identified in Santalaceae and explain the origin of some of the unusual lipids found in this plant family. PMID:24062307

Diversity of Δ12 fatty acid desaturases in santalaceae and their role in production of seed oil acetylenic fatty acids.

PubMed

Okada, Shoko; Zhou, Xue-Rong; Damcevski, Katherine; Gibb, Nerida; Wood, Craig; Hamberg, Mats; Haritos, Victoria S

2013-11-08

Plants in the Santalaceae family, including the native cherry Exocarpos cupressiformis and sweet quandong Santalum acuminatum, accumulate ximenynic acid (trans-11-octadecen-9-ynoic acid) in their seed oil and conjugated polyacetylenic fatty acids in root tissue. Twelve full-length genes coding for microsomal Δ12 fatty acid desaturases (FADs) from the two Santalaceae species were identified by degenerate PCR. Phylogenetic analysis of the predicted amino acid sequences placed five Santalaceae FADs with Δ12 FADs, which include Arabidopsis thaliana FAD2. When expressed in yeast, the major activity of these genes was Δ12 desaturation of oleic acid, but unusual activities were also observed: i.e. Δ15 desaturation of linoleic acid as well as trans-Δ12 and trans-Δ11 desaturations of stearolic acid (9-octadecynoic acid). The trans-12-octadecen-9-ynoic acid product was also detected in quandong seed oil. The two other FAD groups (FADX and FADY) were present in both species; in a phylogenetic tree of microsomal FAD enzymes, FADX and FADY formed a unique clade, suggesting that are highly divergent. The FADX group enzymes had no detectable Δ12 FAD activity but instead catalyzed cis-Δ13 desaturation of stearolic acid when expressed in yeast. No products were detected for the FADY group when expressed recombinantly. Quantitative PCR analysis showed that the FADY genes were expressed in leaf rather than developing seed of the native cherry. FADs with promiscuous and unique activities have been identified in Santalaceae and explain the origin of some of the unusual lipids found in this plant family.

Improved soybean oil quality by targeted mutagenesis of the fatty acid desaturase 2 gene family.

PubMed

Haun, William; Coffman, Andrew; Clasen, Benjamin M; Demorest, Zachary L; Lowy, Anita; Ray, Erin; Retterath, Adam; Stoddard, Thomas; Juillerat, Alexandre; Cedrone, Frederic; Mathis, Luc; Voytas, Daniel F; Zhang, Feng

2014-09-01

Soybean oil is high in polyunsaturated fats and is often partially hydrogenated to increase its shelf life and improve oxidative stability. The trans-fatty acids produced through hydrogenation pose a health threat. Soybean lines that are low in polyunsaturated fats were generated by introducing mutations in two fatty acid desaturase 2 genes (FAD2-1A and FAD2-1B), which in the seed convert the monounsaturated fat, oleic acid, to the polyunsaturated fat, linoleic acid. Transcription activator-like effector nucleases (TALENs) were engineered to recognize and cleave conserved DNA sequences in both genes. In four of 19 transgenic soybean lines expressing the TALENs, mutations in FAD2-1A and FAD2-1B were observed in DNA extracted from leaf tissue; three of the four lines transmitted heritable FAD2-1 mutations to the next generation. The fatty acid profile of the seed was dramatically changed in plants homozygous for mutations in both FAD2-1A and FAD2-1B: oleic acid increased from 20% to 80% and linoleic acid decreased from 50% to under 4%. Further, mutant plants were identified that lacked the TALEN transgene and only carried the targeted mutations. The ability to create a valuable trait in a single generation through targeted modification of a gene family demonstrates the power of TALENs for genome engineering and crop improvement. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Selection in Europeans on Fatty Acid Desaturases Associated with Dietary Changes

PubMed Central

Buckley, Matthew T.; Racimo, Fernando; Allentoft, Morten E.; Jensen, Majken K.; Jonsson, Anna; Huang, Hongyan; Hormozdiari, Farhad; Sikora, Martin; Marnetto, Davide; Eskin, Eleazar; Jørgensen, Marit E.; Grarup, Niels; Pedersen, Oluf; Hansen, Torben; Kraft, Peter; Willerslev, Eske

2017-01-01

Abstract FADS genes encode fatty acid desaturases that are important for the conversion of short chain polyunsaturated fatty acids (PUFAs) to long chain fatty acids. Prior studies indicate that the FADS genes have been subjected to strong positive selection in Africa, South Asia, Greenland, and Europe. By comparing FADS sequencing data from present-day and Bronze Age (5–3k years ago) Europeans, we identify possible targets of selection in the European population, which suggest that selection has targeted different alleles in the FADS genes in Europe than it has in South Asia or Greenland. The alleles showing the strongest changes in allele frequency since the Bronze Age show associations with expression changes and multiple lipid-related phenotypes. Furthermore, the selected alleles are associated with a decrease in linoleic acid and an increase in arachidonic and eicosapentaenoic acids among Europeans; this is an opposite effect of that observed for selected alleles in Inuit from Greenland. We show that multiple SNPs in the region affect expression levels and PUFA synthesis. Additionally, we find evidence for a gene–environment interaction influencing low-density lipoprotein (LDL) levels between alleles affecting PUFA synthesis and PUFA dietary intake: carriers of the derived allele display lower LDL cholesterol levels with a higher intake of PUFAs. We hypothesize that the selective patterns observed in Europeans were driven by a change in dietary composition of fatty acids following the transition to agriculture, resulting in a lower intake of arachidonic acid and eicosapentaenoic acid, but a higher intake of linoleic acid and α-linolenic acid. PMID:28333262

Mutant fatty acid desaturase

DOEpatents

Shanklin, John; Cahoon, Edgar B.

2004-02-03

The present invention relates to a method for producing mutants of a fatty acid desaturase having a substantially increased activity towards fatty acid substrates with chains containing fewer than 18 carbons relative to an unmutagenized precursor desaturase having an 18 carbon atom chain length substrate specificity. The method involves inducing one or more mutations in the nucleic acid sequence encoding the precursor desaturase, transforming the mutated sequence into an unsaturated fatty acid auxotroph cell such as MH13 E. coli, culturing the cells in the absence of supplemental unsaturated fatty acids, thereby selecting for recipient cells which have received and which express a mutant fatty acid desaturase with an elevated specificity for fatty acid substrates having chain lengths of less than 18 carbon atoms. A variety of mutants having 16 or fewer carbon atom chain length substrate specificities are produced by this method. Mutant desaturases produced by this method can be introduced via expression vectors into prokaryotic and eukaryotic cells and can also be used in the production of transgenic plants which may be used to produce specific fatty acid products.

[Functional expression of an omega-3 fatty acid desaturase gene from Glycine max in Saccharomyces cerevisiae].

PubMed

Zhang, Hong-Tao; Yang, Jia-Sen; Shan, Lei; Bi, Yu-Ping

2006-01-01

Alpha-linolenic acid(ALA, C18:3delta9,12,15 ) is an essential fatty acid which has many sanitary functions to human. However, its contents in diets are often not enough. In plants, omega-3 fatty acid desaturases(FAD) catalyze linoleic acid(LA, C18:2delta9,12) into ALA. The seed oil of Glycine max contains high level of ALA. To investigate the functions of Glycine max omega-3FAD, the cDNA of GmFAD3 C was amplified by RT-PCR from immature seeds, then cloned into the shuttle expression vector p416 to generate the recombinant vector p4GFAD3C. The resulting vector was transformed into Saccharomyces cerevisiae K601 throuth LiAc method. The positive clones were screened on the CM(Ura-) medium and identified by PCR, and then cultured in CM (Ura-) liquid medium with exogenous LA in 20 degrees C for three days. The intracellular fatty acid composition of the engineering strain Kp416 and Kp4GFAD3C was analyzed by gas chromatography (GC). A novel peak in strain Kp4GFAD3C was detected,which was not detectable in control, Comparison of the retention times of the newly yielded peak with that of authentic standard indicated that the fatty acid is ALA. The content of ALA reached to 3.1% of the total fatty acid in recombinant strain, the content of LA correspondingly decreased from 22% to 16.2% by contrast. It was suggested that the protein encoded by GmFAD3 C can specifically catalyze 18 carbon PUFA substrate of LA into ALA by taking off hydrogen atoms at delta15 location. In this study, we expressed a Glycine max omega-3 fatty acid desaturase gene in S. cerevisiae; An efficient and economical yeast expressing system(K601-p416 system) which is suitable for the expression of FAD was built.

Omega-3 fatty acid desaturase gene family from two ω-3 sources, Salvia hispanica and Perilla frutescens: Cloning, characterization and expression

PubMed Central

Xue, Yufei; Chen, Baojun; Win, Aung Naing; Fu, Chun; Lian, Jianping; Liu, Xue; Wang, Rui; Zhang, Xingcui

2018-01-01

Omega-3 fatty acid desaturase (ω-3 FAD, D15D) is a key enzyme for α-linolenic acid (ALA) biosynthesis. Both chia (Salvia hispanica) and perilla (Perilla frutescens) contain high levels of ALA in seeds. In this study, the ω-3 FAD gene family was systematically and comparatively cloned from chia and perilla. Perilla FAD3, FAD7, FAD8 and chia FAD7 are encoded by single-copy (but heterozygous) genes, while chia FAD3 is encoded by 2 distinct genes. Only 1 chia FAD8 sequence was isolated. In these genes, there are 1 to 6 transcription start sites, 1 to 8 poly(A) tailing sites, and 7 introns. The 5’UTRs of PfFAD8a/b contain 1 to 2 purine-stretches and 2 pyrimidine-stretches. An alternative splice variant of ShFAD7a/b comprises a 5’UTR intron. Their encoded proteins harbor an FA_desaturase conserved domain together with 4 trans-membrane helices and 3 histidine boxes. Phylogenetic analysis validated their identity of dicot microsomal or plastidial ω-3 FAD proteins, and revealed some important evolutionary features of plant ω-3 FAD genes such as convergent evolution across different phylums, single-copy status in algae, and duplication events in certain taxa. The qRT-PCR assay showed that the ω-3 FAD genes of two species were expressed at different levels in various organs, and they also responded to multiple stress treatments. The functionality of the ShFAD3 and PfFAD3 enzymes was confirmed by yeast expression. The systemic molecular and functional features of the ω-3 FAD gene family from chia and perilla revealed in this study will facilitate their use in future studies on genetic improvement of ALA traits in oilseed crops. PMID:29351555

Tissue-specific impact of FADS cluster variants on FADS1 and FADS2 gene expression.

PubMed

Reynolds, Lindsay M; Howard, Timothy D; Ruczinski, Ingo; Kanchan, Kanika; Seeds, Michael C; Mathias, Rasika A; Chilton, Floyd H

2018-01-01

Omega-6 (n-6) and omega-3 (n-3) long (≥ 20 carbon) chain polyunsaturated fatty acids (LC-PUFAs) play a critical role in human health and disease. Biosynthesis of LC-PUFAs from dietary 18 carbon PUFAs in tissues such as the liver is highly associated with genetic variation within the fatty acid desaturase (FADS) gene cluster, containing FADS1 and FADS2 that encode the rate-limiting desaturation enzymes in the LC-PUFA biosynthesis pathway. However, the molecular mechanisms by which FADS genetic variants affect LC-PUFA biosynthesis, and in which tissues, are unclear. The current study examined associations between common single nucleotide polymorphisms (SNPs) within the FADS gene cluster and FADS1 and FADS2 gene expression in 44 different human tissues (sample sizes ranging 70-361) from the Genotype-Tissue Expression (GTEx) Project. FADS1 and FADS2 expression were detected in all 44 tissues. Significant cis-eQTLs (within 1 megabase of each gene, False Discovery Rate, FDR<0.05, as defined by GTEx) were identified in 12 tissues for FADS1 gene expression and 23 tissues for FADS2 gene expression. Six tissues had significant (FDR< 0.05) eQTLs associated with both FADS1 and FADS2 (including artery, esophagus, heart, muscle, nerve, and thyroid). Interestingly, the identified eQTLs were consistently found to be associated in opposite directions for FADS1 and FADS2 expression. Taken together, findings from this study suggest common SNPs within the FADS gene cluster impact the transcription of FADS1 and FADS2 in numerous tissues and raise important questions about how the inverse expression of these two genes impact intermediate molecular (such a LC-PUFA and LC-PUFA-containing glycerolipid levels) and ultimately clinical phenotypes associated with inflammatory diseases and brain health.

FadD Is Required for Utilization of Endogenous Fatty Acids Released from Membrane Lipids ▿ †

PubMed Central

Pech-Canul, Ángel; Nogales, Joaquina; Miranda-Molina, Alfonso; Álvarez, Laura; Geiger, Otto; Soto, María José; López-Lara, Isabel M.

2011-01-01

FadD is an acyl coenzyme A (CoA) synthetase responsible for the activation of exogenous long-chain fatty acids (LCFA) into acyl-CoAs. Mutation of fadD in the symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti promotes swarming motility and leads to defects in nodulation of alfalfa plants. In this study, we found that S. meliloti fadD mutants accumulated a mixture of free fatty acids during the stationary phase of growth. The composition of the free fatty acid pool and the results obtained after specific labeling of esterified fatty acids with a Δ5-desaturase (Δ5-Des) were in agreement with membrane phospholipids being the origin of the released fatty acids. Escherichia coli fadD mutants also accumulated free fatty acids released from membrane lipids in the stationary phase. This phenomenon did not occur in a mutant of E. coli with a deficient FadL fatty acid transporter, suggesting that the accumulation of fatty acids in fadD mutants occurs inside the cell. Our results indicate that, besides the activation of exogenous LCFA, in bacteria FadD plays a major role in the activation of endogenous fatty acids released from membrane lipids. Furthermore, expression analysis performed with S. meliloti revealed that a functional FadD is required for the upregulation of genes involved in fatty acid degradation and suggested that in the wild-type strain, the fatty acids released from membrane lipids are degraded by β-oxidation in the stationary phase of growth. PMID:21926226

Changes of seed weight, fatty acid composition, oil and protein contents from different peanut FAD2 genotypes at different seed developmental and maturation stages

USDA-ARS?s Scientific Manuscript database

The level of oleic acid in peanut seed is one of the most important factors in determining seed quality and is controlled by two pairs of homeologous genes Fatty Acid Desaturase 2A and 2B (FAD2A and FAD2B). The genotypes of eight F8 breeding lines were determined as AABB, aaBB, AAbb, and aabb by rea...

FADS gene cluster polymorphisms: important modulators of fatty acid levels and their impact on atopic diseases.

PubMed

Lattka, Eva; Illig, Thomas; Heinrich, Joachim; Koletzko, Berthold

2009-01-01

Long-chain polyunsaturated fatty acids (LC-PUFAs) play an important role in several physiological processes and their concentration in phospholipids has been associated with several complex diseases, such as atopic disease. The level and composition of LC-PUFAs in the human body is highly dependent on their intake in the diet or on the intake of fatty acid precursors, which are endogenously elongated and desaturated to physiologically active LC-PUFAs. The most important enzymes in this reaction cascade are the Delta(5) and Delta(6) desaturase. Several studies in the last few years have revealed that single nucleotide polymorphisms (SNPs) in the 2 desaturase encoding genes (FADS1 and FADS2) are highly associated with the concentration of omega-6 and omega-3 fatty acids, showing that beside nutrition, genetic factors also play an important role in the regulation of LC-PUFAs. This review focuses on current knowledge of the impact of genetic polymorphisms on LC-PUFA metabolism and on their potential role in the development of atopic diseases. Copyright (c) 2009 S. Karger AG, Basel.

The impact of FADS genetic variants on ω6 polyunsaturated fatty acid metabolism in African Americans

PubMed Central

2011-01-01

Background Arachidonic acid (AA) is a long-chain omega-6 polyunsaturated fatty acid (PUFA) synthesized from the precursor dihomo-gamma-linolenic acid (DGLA) that plays a vital role in immunity and inflammation. Variants in the Fatty Acid Desaturase (FADS) family of genes on chromosome 11q have been shown to play a role in PUFA metabolism in populations of European and Asian ancestry; no work has been done in populations of African ancestry to date. Results In this study, we report that African Americans have significantly higher circulating levels of plasma AA (p = 1.35 × 10-48) and lower DGLA levels (p = 9.80 × 10-11) than European Americans. Tests for association in N = 329 individuals across 80 nucleotide polymorphisms (SNPs) in the Fatty Acid Desaturase (FADS) locus revealed significant association with AA, DGLA and the AA/DGLA ratio, a measure of enzymatic efficiency, in both racial groups (peak signal p = 2.85 × 10-16 in African Americans, 2.68 × 10-23 in European Americans). Ancestry-related differences were observed at an upstream marker previously associated with AA levels (rs174537), wherein, 79-82% of African Americans carry two copies of the G allele compared to only 42-45% of European Americans. Importantly, the allelic effect of the G allele, which is associated with enhanced conversion of DGLA to AA, on enzymatic efficiency was similar in both groups. Conclusions We conclude that the impact of FADS genetic variants on PUFA metabolism, specifically AA levels, is likely more pronounced in African Americans due to the larger proportion of individuals carrying the genotype associated with increased FADS1 enzymatic conversion of DGLA to AA. PMID:21599946

Genetic variants in desaturase gene, erythrocyte fatty acids, and risk for type 2 diabetes in Chinese Hans.

PubMed

Huang, Tao; Sun, Jianqin; Chen, Yanqiu; Xie, Hua; Xu, Danfeng; Huang, Jinyan; Li, Duo

2014-01-01

The aim of this study was to examine the association of the genetic variants in the fatty acid desaturase (FADS) gene cluster with erythrocyte phospholipid fatty acids (PLFA), and their relation to risk for type 2 diabetes mellitus (T2DM) in Han Chinese. Seven hundred and fifty-eight patients with T2DM and 400 healthy individuals were recruited. The erythrocyte PLFA and single-nucleotide polymorphism were determined by standard method. Minor allele homozygotes and heterozygotes of rs174575 and rs174537 had lower PL 20:4 ω-6 levels in healthy individuals. Minor allele homozygotes and heterozygotes of rs174455 in FADS3 gene had lower levels of 22:5 ω-3, 20:4 ω-6, and Δ5desaturase activity in patients with T2DM. Erythrocyte membrane PL 18:3 ω-3 (P for trend = 0.002), 22:5 ω-3 (P for trend < 0.001), ω-3 polyunsaturated fatty acid (P for trend < 0.001), and ω-3:ω-6 (P for trend < 0.001) were significantly inversely associated with risk for T2DM. Genetic variants in the FADS gene cluster are associated with altered erythrocyte PLFAs. High levels of PL 18:3 ω-3, 22:5 ω-3, and total ω-3 polyunsaturated fatty acid were associated with low risk for T2DM. Copyright © 2014 Elsevier Inc. All rights reserved.

A New F131V Mutation in Chlamydomonas Phytoene Desaturase Locates a Cluster of Norflurazon Resistance Mutations near the FAD-Binding Site in 3D Protein Models

PubMed Central

Suarez, Julio V.; Banks, Stephen; Thomas, Paul G.; Day, Anil

2014-01-01

The green alga Chlamydomonas reinhardtii provides a tractable genetic model to study herbicide mode of action using forward genetics. The herbicide norflurazon inhibits phytoene desaturase, which is required for carotenoid synthesis. Locating amino acid substitutions in mutant phytoene desaturases conferring norflurazon resistance provides a genetic approach to map the herbicide binding site. We isolated a UV-induced mutant able to grow in very high concentrations of norflurazon (150 µM). The phytoene desaturase gene in the mutant strain contained the first resistance mutation to be localised to the dinucleotide-binding Rossmann-likedomain. A highly conserved phenylalanine amino acid at position 131 of the 564 amino acid precursor protein was changed to a valine in the mutant protein. F131, and two other amino acids whose substitution confers norflurazon resistance in homologous phytoene desaturase proteins, map to distant regions in the primary sequence of the C. reinhardtii protein (V472, L505) but in tertiary models these residues cluster together to a region close to the predicted FAD binding site. The mutant gene allowed direct 5 µM norflurazon based selection of transformants, which were tolerant to other bleaching herbicides including fluridone, flurtamone, and diflufenican but were more sensitive to beflubutamid than wild type cells. Norflurazon resistance and beflubutamid sensitivity allow either positive or negative selection against transformants expressing the mutant phytoene desaturase gene. PMID:24936791

A study of associations between early DHA status and fatty acid desaturase (FADS) SNP and developmental outcomes in children of obese mothers.

PubMed

Andersen, Karina R; Harsløf, Laurine B S; Schnurr, Theresia M; Hansen, Torben; Hellgren, Lars I; Michaelsen, Kim F; Lauritzen, Lotte

2017-01-01

DHA from diet or endogenous synthesis has been proposed to affect infant development, however, results are inconclusive. In this study, we aim to verify previously observed fatty acid desaturase gene cluster (FADS) SNP-specific associations with erythrocyte DHA status in 9-month-old children and sex-specific association with developmental outcomes. The study was performed in 166 children (55 % boys) of obese mothers. Erythrocyte fatty acid composition was analysed in blood-samples obtained at 9 months of age, and developmental outcomes assessed by the Ages and Stages Questionnaire at 3 years. Erythrocyte DHA level ranged from 4·4 to 9·9 % of fatty acids, but did not show any association with FADS SNP or other potential determinants. Regression analysis showed associations between erythrocyte DHA and scores for personal-social skills (β 1·8 (95 % CI 0·3, 3·3), P=0·019) and problem solving (β 3·4 (95 % CI 1·2, 5·6), P=0·003). A tendency was observed for an association in opposite direction between minor alleles (G-variant) of rs1535 and rs174575 and personal-social skills (P=0·062 and 0·068, respectively), which became significant when the SNP were combined based on their previously observed effect on erythrocyte DHA at 9 months of age (β 2·6 (95 % CI 0·01, 5·1), P=0·011). Sex-SNP interaction was indicated for rs174575 genotype on fine motor scores (P=0·016), due to higher scores among minor allele carrying girls (P=0·043), whereas no effect was seen among boys. In conclusion, DHA-increasing FADS SNP and erythrocyte DHA status were consistently associated with improved personal-social skills in this small cohort of children of obese mothers irrespective of sex, but the sample was too small to verify potential sex-specific effects.

Mutant alleles of FAD2-1A and FAD2-1B combine to produce soybeans with the high oleic acid seed oil trait

PubMed Central

2010-01-01

Background The alteration of fatty acid profiles in soybean [Glycine max (L.) Merr.] to improve soybean oil quality is an important and evolving theme in soybean research to meet nutritional needs and industrial criteria in the modern market. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of the oil. Commodity soybean oil typically contains 20% oleic acid and the target for high oleic acid soybean oil is approximately 80% of the oil; previous conventional plant breeding research to raise the oleic acid level to just 50-60% of the oil was hindered by the genetic complexity and environmental instability of the trait. The objective of this work was to create the high oleic acid trait in soybeans by identifying and combining mutations in two delta-twelve fatty acid desaturase genes, FAD2-1A and FAD2-1B. Results Three polymorphisms found in the FAD2-1B alleles of two soybean lines resulted in missense mutations. For each of the two soybean lines, there was one unique amino acid change within a highly conserved region of the protein. The mutant FAD2-1B alleles were associated with an increase in oleic acid levels, although the FAD2-1B mutant alleles alone were not capable of producing a high oleic acid phenotype. When existing FAD2-1A mutations were combined with the novel mutant FAD2-1B alleles, a high oleic acid phenotype was recovered only for those lines which were homozygous for both of the mutant alleles. Conclusions We were able to produce conventional soybean lines with 80% oleic acid in the oil in two different ways, each requiring the contribution of only two genes. The high oleic acid soybean germplasm developed contained a desirable fatty acid profile, and it was stable in two production environments. The presumed causative sequence polymorphisms in the FAD2-1B alleles were developed into highly efficient molecular markers for tracking the mutant alleles. The resources

Mutant alleles of FAD2-1A and FAD2-1B combine to produce soybeans with the high oleic acid seed oil trait.

PubMed

Pham, Anh-Tung; Lee, Jeong-Dong; Shannon, J Grover; Bilyeu, Kristin D

2010-09-09

The alteration of fatty acid profiles in soybean [Glycine max (L.) Merr.] to improve soybean oil quality is an important and evolving theme in soybean research to meet nutritional needs and industrial criteria in the modern market. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of the oil. Commodity soybean oil typically contains 20% oleic acid and the target for high oleic acid soybean oil is approximately 80% of the oil; previous conventional plant breeding research to raise the oleic acid level to just 50-60% of the oil was hindered by the genetic complexity and environmental instability of the trait. The objective of this work was to create the high oleic acid trait in soybeans by identifying and combining mutations in two delta-twelve fatty acid desaturase genes, FAD2-1A and FAD2-1B. Three polymorphisms found in the FAD2-1B alleles of two soybean lines resulted in missense mutations. For each of the two soybean lines, there was one unique amino acid change within a highly conserved region of the protein. The mutant FAD2-1B alleles were associated with an increase in oleic acid levels, although the FAD2-1B mutant alleles alone were not capable of producing a high oleic acid phenotype. When existing FAD2-1A mutations were combined with the novel mutant FAD2-1B alleles, a high oleic acid phenotype was recovered only for those lines which were homozygous for both of the mutant alleles. We were able to produce conventional soybean lines with 80% oleic acid in the oil in two different ways, each requiring the contribution of only two genes. The high oleic acid soybean germplasm developed contained a desirable fatty acid profile, and it was stable in two production environments. The presumed causative sequence polymorphisms in the FAD2-1B alleles were developed into highly efficient molecular markers for tracking the mutant alleles. The resources described here for the creation

Fads1 and 2 are promoted to meet instant need for long-chain polyunsaturated fatty acids in goose fatty liver.

PubMed

Osman, Rashid H; Liu, Long; Xia, Lili; Zhao, Xing; Wang, Qianqian; Sun, Xiaoxian; Zhang, Yihui; Yang, Biao; Zheng, Yun; Gong, Daoqing; Geng, Tuoyu

2016-07-01

Global prevalence of non-alcoholic fatty liver disease (NAFLD) constitutes a threat to human health. Goose is a unique model of NAFLD for discovering therapeutic targets as its liver can develop severe steatosis without overt injury. Fatty acid desaturase (Fads) is a potential therapeutic target as Fads expression and mutations are associated with liver fat. Here, we hypothesized that Fads was promoted to provide a protection for goose fatty liver. To test this, goose Fads1 and Fads2 were sequenced. Fads1/2/6 expression was determined in goose liver and primary hepatocytes by quantitative PCR. Liver fatty acid composition was also analyzed by gas chromatography. Data indicated that hepatic Fads1/2/6 expression was gradually increased with the time of overfeeding. In contrast, trans-C18:1n9 fatty acid (Fads inhibitor) was reduced. However, enhanced Fads capacity for long-chain polyunsaturated fatty acid (LC-PUFA) synthesis was not sufficient to compensate for the depleted LC-PUFAs in goose fatty liver. Moreover, cell studies showed that Fads1/2/6 expression was regulated by fatty liver-associated factors. Together, these findings suggest Fads1/2 as protective components are promoted to meet instant need for LC-PUFAs in goose fatty liver, and we propose this is required for severe hepatic steatosis without liver injury.

Mutagenesis of FAD2 genes in peanut with CRISPR/Cas9

USDA-ARS?s Scientific Manuscript database

The CRISPR/Cas9 system is known for its precise and efficient gene-editing of a targeted region in a variety of organisms including plants. We targeted FAD2 gene region to perform CRISPR/Cas9 gene-editing in peanut. The FAD2 gene encodes fatty acid desaturase which catalyzes the conversion of oleic ...

Identification and evaluation of ω-3 fatty acid desaturase genes for hyperfortifying α-linolenic acid in transgenic rice seed.

PubMed

Liu, Hua Liang; Yin, Zhi Jie; Xiao, Li; Xu, Yi Nong; Qu, Le Qing

2012-05-01

α-Linolenic acid (ALA) deficiency and a skewed of ω6:ω3 fatty acid ratio in the diet are a major explanation for the prevalence of cardiovascular diseases and inflammatory/autoimmune diseases. There is a need to enhance the ALA content and to reduce the ratio of linoleic acid (LA) to ALA. Six ω-3 (Δ-15) fatty acid desaturase (FAD) genes were cloned from rice and soybean. The subcellular localizations of the proteins were identified. The FAD genes were introduced into rice under the control of an endosperm-specific promoter, GluC, or a Ubi-1 promoter to evaluate their potential in increasing the ALA content in seeds. The ALA contents in the seeds of endoplasmic reticulum (ER)-localized GmFAD3-1 and OsFAD3 overexpression lines increased from 0.36 mg g⁻¹ to 8.57 mg g⁻¹ and 10.06 mg g⁻¹, respectively, which was 23.8- and 27.9-fold higher than that of non-transformants. The trait of high ALA content was stably inheritable over three generations. Homologous OsFAD3 is more active than GmFAD3-1 in catalysing LA conversion to ALA in rice seeds. Overexpression of ER-localized GmFAD3-2/3 and chloroplast-localized OsFAD7/8 had less effect on increasing the ALA content in rice seeds. The GluC promoter is advantageous compared with Ubi-1 in this experimental system. The enhanced ALA was preferentially located at the sn-2 position in triacylglycerols. A meal-size portion of high ALA rice would meet >80% of the daily adult ALA requirement. The ALA-rich rice could be expected to ameliorate much of the global dietary ALA deficiency.

FADS genetic variants and omega-6 polyunsaturated fatty acid metabolism in a homogeneous island population.

PubMed

Mathias, Rasika A; Vergara, Candelaria; Gao, Li; Rafaels, Nicholas; Hand, Tracey; Campbell, Monica; Bickel, Carol; Ivester, Priscilla; Sergeant, Susan; Barnes, Kathleen C; Chilton, Floyd H

2010-09-01

Long-chain polyunsaturated fatty acids (PUFA) orchestrate immunity and inflammation through their capacity to be converted to potent inflammatory mediators. We assessed associations of FADS gene cluster polymorphisms and fasting serum PUFA concentrations in a fully ascertained, geographically isolated founder population of European descent. Concentrations of 22 PUFAs were determined by gas chromatography, of which ten fatty acids and five ratios defining FADS1 and FADS2 activity were tested for genetic association against 16 single nucleotide polymorphisms (SNP) in 224 individuals. A cluster of SNPs in tight linkage disequilibrium in the FADS1 gene (rs174537, rs174545, rs174546, rs174553, rs174556, rs174561, rs174568, and rs99780) were strongly associated with arachidonic acid (AA) (P = 5.8 x 10(-7) - 1.7 x 10(-8)) among other PUFAs, but the strongest associations were with the ratio measuring FADS1 activity in the omega-6 series (P = 2.11 x 10(-13) - 1.8 x 10(-20)). The minor allele across all SNPs was consistently associated with decreased omega-6 PUFAs, with the exception of dihomo-gamma-linoleic acid (DHGLA), where the minor allele was consistently associated with increased levels. Our findings in a geographically isolated population with a homogenous dietary environment suggest that variants in the Delta-5 desaturase enzymatic step likely regulate the efficiency of conversion of medium-chain PUFAs to potentially inflammatory PUFAs, such as AA.

Loss of Function of FATTY ACID DESATURASE7 in Tomato Enhances Basal Aphid Resistance in a Salicylate-Dependent Manner1[W][OA

PubMed Central

Avila, Carlos A.; Arévalo-Soliz, Lirio M.; Jia, Lingling; Navarre, Duroy A.; Chen, Zhaorigetu; Howe, Gregg A.; Meng, Qing-Wei; Smith, Jonathon E.; Goggin, Fiona L.

2012-01-01

We report here that disruption of function of the ω-3 FATTY ACID DESATURASE7 (FAD7) enhances plant defenses against aphids. The suppressor of prosystemin-mediated responses2 (spr2) mutation in tomato (Solanum lycopersicum), which eliminates the function of FAD7, reduces the settling behavior, survival, and fecundity of the potato aphid (Macrosiphum euphorbiae). Likewise, the antisense suppression of LeFAD7 expression in wild-type tomato plants reduces aphid infestations. Aphid resistance in the spr2 mutant is associated with enhanced levels of salicylic acid (SA) and mRNA encoding the pathogenesis-related protein P4. Introduction of the Naphthalene/salicylate hydroxylase transgene, which suppresses SA accumulation, restores wild-type levels of aphid susceptibility to spr2. Resistance in spr2 is also lost when we utilize virus-induced gene silencing to suppress the expression of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1), a positive regulator of many SA-dependent defenses. These results indicate that FAD7 suppresses defenses against aphids that are mediated through SA and NPR1. Although loss of function of FAD7 also inhibits the synthesis of jasmonate (JA), the effects of this desaturase on aphid resistance are not dependent on JA; other mutants impaired in JA synthesis (acx1) or perception (jai1-1) show wild-type levels of aphid susceptibility, and spr2 retains aphid resistance when treated with methyl jasmonate. Thus, FAD7 may influence JA-dependent defenses against chewing insects and SA-dependent defenses against aphids through independent effects on JA synthesis and SA signaling. The Arabidopsis (Arabidopsis thaliana) mutants Atfad7-2 and Atfad7-1fad8 also show enhanced resistance to the green peach aphid (Myzus persicae) compared with wild-type controls, indicating that FAD7 influences plant-aphid interactions in at least two plant families. PMID:22291202

Formation of conjugated delta8,delta10-double bonds by delta12-oleic-acid desaturase-related enzymes: biosynthetic origin of calendic acid.

PubMed

Cahoon, E B; Ripp, K G; Hall, S E; Kinney, A J

2001-01-26

Divergent forms of the plant Delta(12)-oleic-acid desaturase (FAD2) have previously been shown to catalyze the formation of acetylenic bonds, epoxy groups, and conjugated Delta(11),Delta(13)-double bonds by modification of an existing Delta(12)-double bond in C(18) fatty acids. Here, we report a class of FAD2-related enzymes that modifies a Delta(9)-double bond to produce the conjugated trans-Delta(8),trans-Delta(10)-double bonds found in calendic acid (18:3Delta(8trans,10trans,12cis)), the major component of the seed oil of Calendula officinalis. Using an expressed sequence tag approach, cDNAs for two closely related FAD2-like enzymes, designated CoFADX-1 and CoFADX-2, were identified from a C. officinalis developing seed cDNA library. The deduced amino acid sequences of these polypeptides share 40-50% identity with those of other FAD2 and FAD2-related enzymes. Expression of either CoFADX-1 or CoFADX-2 in somatic soybean embryos resulted in the production of calendic acid. In embryos expressing CoFADX-2, calendic acid accumulated to as high as 22% (w/w) of the total fatty acids. In addition, expression of CoFADX-1 and CoFADX-2 in Saccharomyces cerevisiae was accompanied by calendic acid accumulation when induced cells were supplied exogenous linoleic acid (18:2Delta(9cis,12cis)). These results are thus consistent with a route of calendic acid synthesis involving modification of the Delta(9)-double bond of linoleic acid. Regiospecificity for Delta(9)-double bonds is unprecedented among FAD2-related enzymes and further expands the functional diversity found in this family of enzymes.

Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

PubMed Central

Lee, Je Min; Lee, Hyungjae; Kang, SeokBeom; Park, Woo Jung

2016-01-01

Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism. PMID:26742061

Genome-Wide Survey and Characterization of Fatty Acid Desaturase Gene Family in Brassica napus and Its Parental Species.

PubMed

Xue, Yufei; Chen, Baojun; Wang, Rui; Win, Aung Naing; Li, Jiana; Chai, Yourong

2018-02-01

Rapeseed (Brassica napus) is an important oilseed crop worldwide, and fatty acid (FA) compositions determine the nutritional and economic value of its seed oil. Fatty acid desaturases (FADs) play a pivotal role in regulating FA compositions, but to date, no comprehensive genome-wide analysis of FAD gene family in rapeseed and its parent species has been reported. In this study, using homology searches, 84, 45, and 44 FAD genes were identified in rapeseed, Brassica rapa, and Brassica oleracea genomes, respectively. These FAD genes were unevenly located in 17 chromosomes and 2 scaffolds of rapeseed, 9 chromosomes and 1 scaffold of B. rapa, and all the chromosomes of B. oleracea. Phylogenetic analysis showed that the soluble and membrane-bound FADs in the three Brassica species were divided into four and six subfamilies, respectively. Generally, the soluble FADs contained two conserved histidine boxes, while three highly conserved histidine boxes were harbored in membrane-bound FADs. Exon-intron structure, intron phase, and motif composition and position were highly conserved in each FAD subfamily. Putative subcellular locations of FAD proteins in three Brassica species were consistent with those of corresponding known FADs. In total, 25 of simple sequence repeat (SSR) loci were found in FAD genes of the three Brassica species. Transcripts of selected FAD genes in the three species were examined in various organs/tissues or stress treatments from NCBI expressed sequence tag (EST) database. This study provides a critical molecular basis for quality improvement of rapeseed oil and facilitates our understanding of key roles of FAD genes in plant growth and development and stress response.

FADS genetic variants and ω-6 polyunsaturated fatty acid metabolism in a homogeneous island population[S

PubMed Central

Mathias, Rasika A.; Vergara, Candelaria; Gao, Li; Rafaels, Nicholas; Hand, Tracey; Campbell, Monica; Bickel, Carol; Ivester, Priscilla; Sergeant, Susan; Barnes, Kathleen C.; Chilton, Floyd H.

2010-01-01

Long-chain polyunsaturated fatty acids (PUFA) orchestrate immunity and inflammation through their capacity to be converted to potent inflammatory mediators. We assessed associations of FADS gene cluster polymorphisms and fasting serum PUFA concentrations in a fully ascertained, geographically isolated founder population of European descent. Concentrations of 22 PUFAs were determined by gas chromatography, of which ten fatty acids and five ratios defining FADS1 and FADS2 activity were tested for genetic association against 16 single nucleotide polymorphisms (SNP) in 224 individuals. A cluster of SNPs in tight linkage disequilibrium in the FADS1 gene (rs174537, rs174545, rs174546, rs174553, rs174556, rs174561, rs174568, and rs99780) were strongly associated with arachidonic acid (AA) (P = 5.8 × 10−7 – 1.7 × 10−8) among other PUFAs, but the strongest associations were with the ratio measuring FADS1 activity in the ω-6 series (P = 2.11 × 10−13 – 1.8 × 10−20). The minor allele across all SNPs was consistently associated with decreased ω-6 PUFAs, with the exception of dihomo-γ-linoleic acid (DHGLA), where the minor allele was consistently associated with increased levels. Our findings in a geographically isolated population with a homogenous dietary environment suggest that variants in the Δ-5 desaturase enzymatic step likely regulate the efficiency of conversion of medium-chain PUFAs to potentially inflammatory PUFAs, such as AA. PMID:20562440

FADS2 genotype influences whole-body resting fat oxidation in young adult men.

PubMed

Roke, Kaitlin; Jannas-Vela, Sebastian; Spriet, Lawrence L; Mutch, David M

2016-07-01

Considerable evidence supports an association between fatty acid desaturase 2 (FADS2) polymorphisms and the efficiency of converting alpha-linolenic acid (ALA) into eicosapentaenoic acid (EPA) via the desaturation-elongation pathway. However, ALA conversion into EPA represents only 1 of the metabolic fates for this essential fatty acid, as ALA is also highly oxidized. This study demonstrates for the first time that genetic variation in FADS2 (rs174576) is not only associated with the activity of the desaturation-elongation pathway, but also whole-body fat oxidation.

Transcript profiling and gene characterization of three fatty acid desaturase genes in high, moderate, and low linolenic acid genotypes of flax (Linum usitatissimum L.) and their role in linolenic acid accumulation.

PubMed

Banik, Mitali; Duguid, Scott; Cloutier, Sylvie

2011-06-01

Three genes encoding fatty acid desaturase 3 (fad3a, fad3b, and a novel fad3c) were cloned from four flax genotypes varying in linolenic acid content. Real-time PCR was used to quantify expression levels of the three fad3 genes during seed development. High amounts of both fad3a and fad3b transcripts were observed and reached their peak levels at 20 days after anthesis, except for fad3a from SP2047 where only low level expression was observed throughout seed development. Transcript accumulation of the novel fad3c gene was at similar background levels. The fatty acid composition was analysed for all genotypes and stages of development and compared with the fad3 gene expression patterns. α-Linolenic acid gradually accumulated during seed development, while linoleic acid was transient and decreased in M5791, UGG5-5, and AC McDuff. In contrast, the linolenic acid present in the early stages of development nearly completely disappeared in SP2047, while linoleic acid steadily accumulated. fad3a of the low linolenic acid line SP2047 encoded a truncated protein caused by a premature stop codon resulting from a single point mutation, and the low level of transcript accumulation in this genotype is likely due to nonsense-mediated mRNA decay caused by the premature termination of translation as a result of this early stop codon. Although substantial amounts of transcript accumulation occurred with fad3b of SP2047 genotype, cloning of the gene revealed a mutation in the first histidine box causing an amino acid change. Heterologous expression in yeast of the SP2047 and UGG5-5 fad3b genes showed that the mutation in the histidine box in SP2047 caused the enzyme inactivity. Taken together, these results showed that fad3a and fad3b are responsible for linolenic acid accumulation in flax seeds but did not support a major role for the novel fad3c. These observations were further supported by phenotypic and genotypic assessment of a doubled haploid population. Expression patterns

Omega-3 fatty acid deficiency selectively up-regulates delta6-desaturase expression and activity indices in rat liver: prevention by normalization of omega-3 fatty acid status.

PubMed

Hofacer, Rylon; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Magrisso, I Jack; Benoit, Stephen C; McNamara, Robert K

2011-09-01

This study investigated the effects of perinatal dietary omega-3 (n-3) fatty acid depletion and subsequent repletion on the expression of genes that regulate long-chain (LC) polyunsaturated fatty acid biosynthesis in rat liver and brain. It was hypothesized that chronic n-3 fatty acid deficiency would increase liver Fads1 and Fads2 messenger RNA (mRNA) expression/activity and that n-3 fatty acid repletion would normalize this response. Adult rats fed the n-3-free diet during perinatal development exhibited significantly lower erythrocyte, liver, and frontal cortex LCn-3 fatty acid composition and reciprocal elevations in LC omega-6 (n-6) fatty acid composition compared with controls (CONs) and repleted rats. Liver Fads2, but not Fads1, Elovl2, or Elovl5, mRNA expression was significantly greater in n-3-deficient (DEF) rats compared with CONs and was partially normalized in repleted rats. The liver 18:3n-6/18:2n-6 ratio, an index of delta6-desturase activity, was significantly greater in DEF rats compared with CON and repleted rats and was positively correlated with Fads2 mRNA expression among all rats. The liver 18:3n-6/18:2n-6 ratio, but not Fads2 mRNA expression, was also positively correlated with erythrocyte and frontal cortex LCn-6 fatty acid compositions. Neither Fads1 or Fads2 mRNA expression was altered in brain cortex of DEF rats. These results confirm previous findings that liver, but not brain, delta6-desaturase expression and activity indices are negatively regulated by dietary n-3 fatty acids. Copyright © 2011 Elsevier Inc. All rights reserved.

Two ω-3 FADs Are Associated with Peach Fruit Volatile Formation

PubMed Central

Wang, Jiao-Jiao; Liu, Hong-Ru; Gao, Jie; Huang, Yu-Ji; Zhang, Bo; Chen, Kun-Song

2016-01-01

Aroma-related volatiles, together with sugars and acids, play an important role in determining fruit flavor quality. Characteristic volatiles of peach fruit are mainly derived from fatty acids such as linoleic acid (18:2) and linolenic acid (18:3). In the present study, six genes encoding fatty acid desaturases (FAD) were cloned, including two ω-6 FAD genes (PpFAD2, PpFAD6) and four ω-3 FAD genes (PpFAD3-1, PpFAD3-2, PpFAD7 and PpFAD8). Heterologous expression of peach FADs in tobacco plants showed that PpFAD3-1, and PpFAD3-2 significantly reduced contents of 18:2, and accumulated significant higher levels of 18:3. In the case of volatiles, transgenic plants produced lower concentrations of hexanal and higher levels of (E)-2-hexenal. Consequently, the ratio of the (E)-2-hexenal and hexanal was about 5- and 3-fold higher than that of wild type (WT) in PpFAD3-1 and PpFAD3-2 transformants, respectively. No significant changes in volatile profiles were observed in transgenic plants overexpressing the four other peach FAD genes. Real-time quantitative polymerase chain reaction (qPCR) analysis showed that ripe fruit had high PpFAD3-1 and low PpFAD3-2 transcript levels. In contrast, high PpFAD3-2 and low PpFAD3-1 transcript levels were observed in young fruit. These results indicate a temporal regulation of these two ω-3 FADs during development and ripening, influencing peach fruit volatile formation. PMID:27043529

Multiple genes for functional 6 fatty acyl desaturases (Fad) in Atlantic salmon (Salmo salar L.): gene and cDNA characterization, functional expression, tissue distribution and nutritional regulation.

PubMed

Monroig, Oscar; Zheng, Xiaozhong; Morais, Sofia; Leaver, Michael J; Taggart, John B; Tocher, Douglas R

2010-09-01

Fish are the primary source in the human food basket of the n-3 long-chain polyunsaturated fatty acids, eicosapentaenoate (EPA; 20:5n-3) and docosahexaenoate (DHA; 22:6n-3), that are crucial to the health of higher vertebrates. Atlantic salmon are able to synthesize EPA and DHA from 18:3n-3 through reactions catalyzed by fatty acyl desaturases (Fad) and elongases of very long chain fatty acids. Previously, two cDNAs encoding functionally distinct Delta5 and Delta6 Fads were isolated, but screening of a genomic DNA library revealed the existence of more putative fad genes in the Atlantic salmon genome. In the present study, we show that there are at least four genes encoding putative Fad proteins in Atlantic salmon. Two genes, Delta6fad_a and Delta5fad, corresponded to the previously cloned Delta6 and Delta5 Fad cDNAs. Functional characterization by heterologous expression in yeast showed that the cDNAs for both the two further putative fad genes, Delta6fad_b and Delta6fad_c, had only Delta6 activity, converting 47 % and 12 % of 18:3n-3 to 18:4n-3, and 25 and 7 % of 18:2n-6 to 18:3n-6, for 6Fad_b and Delta6fad_c, respectively. Both 6fad_a and 6fad_b genes were highly expressed in intestine (pyloric caeca), liver and brain, with 6fad_b also highly expressed in gill, whereas 6fad_c transcript was found predominantly in brain, with lower expression levels in all other tissues. The expression levels of the 6fad_a gene in liver and the 6fad_b gene in intestine were significantly higher in fish fed diets containing vegetable oil compared to fish fed fish oil suggesting up-regulation in response to reduced dietary EPA and DHA. In contrast, no significant differences were found between transcript levels for 6fad_a in intestine, 6fad_b in liver, or 6fad_c in liver or intestine of fish fed vegetable oil compared to fish fed fish oil. The observed differences in tissue expression and nutritional regulation of the fad genes are discussed in relation to gene structures and fish

Gene-diet interaction of a common FADS1 variant with marine polyunsaturated fatty acids for fatty acid composition in plasma and erythrocytes among men.

PubMed

Takkunen, Markus J; de Mello, Vanessa D; Schwab, Ursula S; Kuusisto, Johanna; Vaittinen, Maija; Ågren, Jyrki J; Laakso, Markku; Pihlajamäki, Jussi; Uusitupa, Matti I J

2016-02-01

Limited information exists on how the relationship between dietary intake of fat and fatty acids in erythrocytes and plasma is modulated by polymorphisms in the FADS gene cluster. We examined gene-diet interaction of total marine PUFA intake with a known gene encoding Δ-5 desaturase enzyme (FADS1) variant (rs174550) for fatty acids in erythrocyte membranes and plasma phospholipids (PL), cholesteryl esters (CE), and triglycerides (TG). In this cross-sectional study, fatty acid compositions were measured using GC, and total intake of polyunsaturated fat from fish and fish oil was estimated using a food frequency questionnaire in a subsample (n = 962) of the Metabolic Syndrome in Men Study. We found nominally significant gene-diet interactions for eicosapentaenoic acid (EPA, 20:5n-3) in erythrocytes (pinteraction = 0.032) and for EPA in plasma PL (pinteraction = 0.062), CE (pinteraction = 0.035), and TG (pinteraction = 0.035), as well as for docosapentaenoic acid (22:5n-3) in PL (pinteraction = 0.007). After excluding omega-3 supplement users, we found a significant gene-diet interaction for EPA in erythrocytes (pinteraction < 0.003). In a separate cohort of the Kuopio Obesity Surgery Study, the same locus was strongly associated with hepatic mRNA expression of FADS1 (p = 1.5 × 10(-10) ). FADS1 variants may modulate the relationship between marine fatty acid intake and circulating levels of long-chain omega-3 fatty acids. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genetic and epigenetic transgenerational implications related to omega-3 fatty acids. Part I: maternal FADS2 genotype and DNA methylation correlate with polyunsaturated fatty acid status in toddlers: an exploratory analysis.

PubMed

Lupu, Daniel S; Cheatham, Carol L; Corbin, Karen D; Niculescu, Mihai D

2015-11-01

Polyunsaturated fatty acid metabolism in toddlers is regulated by a complex network of interacting factors. The contribution of maternal genetic and epigenetic makeup to this milieu is not well understood. In a cohort of mothers and toddlers 16 months of age (n = 65 mother-child pairs), we investigated the association between maternal genetic and epigenetic fatty acid desaturase 2 (FADS2) profiles and toddlers' n-6 and n-3 fatty acid metabolism. FADS2 rs174575 variation and DNA methylation status were interrogated in mothers and toddlers, as well as food intake and plasma fatty acid concentrations in toddlers. A multivariate fit model indicated that maternal rs174575 genotype, combined with DNA methylation, can predict α-linolenic acid plasma concentration in all toddlers and arachidonic acid concentrations in boys. Arachidonic acid intake was predictive for its plasma concentration in girls, whereas intake of 3 major n-3 species (eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were predictive for their plasma concentrations in boys. FADS2 genotype and DNA methylation in toddlers were not related to plasma concentrations or food intakes, except for CpG8 methylation. Maternal FADS2 methylation was a predictor for the boys' α-linolenic acid intakes. This exploratory study suggests that maternal FADS2 genetic and epigenetic status could be related to toddlers' polyunsaturated fatty acid metabolism. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel FAD2-1 A allele in a soybean plant introduction offers an alternate means to produce soybean seed oil with 85% oleic acid content.

PubMed

Pham, Anh-Tung; Lee, Jeong-Dong; Shannon, J Grover; Bilyeu, Kristin D

2011-09-01

The alteration of fatty acid profiles in soybean to improve soybean oil quality has been a long-time goal of soybean researchers. Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative stability of soybean oil compared to other oils. In the lipid biosynthetic pathway, the enzyme fatty acid desaturase 2 (FAD2) is responsible for the conversion of oleic acid precursors to linoleic acid precursors in developing soybean seeds. Two genes encoding FAD2-1A and FAD2-1B were identified to be expressed specifically in seeds during embryogenesis and have been considered to hold an important role in controlling the seed oleic acid content. A total of 22 soybean plant introduction (PI) lines identified to have an elevated oleic acid content were characterized for sequence mutations in the FAD 2-1A and FAD2-1B genes. PI 603452 was found to contain a deletion of a nucleotide in the second exon of FAD2-1A. These important SNPs were used in developing molecular marker genotyping assays. The assays appear to be a reliable and accurate tool to identify the FAD 2-1A and FAD2-1B genotype of wild-type and mutant plants. PI 603452 was subsequently crossed with PI 283327, a soybean line that has a mutation in FAD2-1B. Interestingly, soybean lines carrying both homozygous insertion/deletion mutation (indel) FAD2-1A alleles and mutant FAD2-1B alleles have an average of 82-86% oleic acid content, compared to 20% in conventional soybean, and low levels of linoleic and linolenic acids. The newly identified indel mutation in the FAD2-1A gene offers a simple method for the development of high oleic acid commercial soybean varieties.

Combinations of mutant FAD2 and FAD3 genes to produce high oleic acid and low linolenic acid soybean oil.

PubMed

Pham, Anh-Tung; Shannon, J Grover; Bilyeu, Kristin D

2012-08-01

High oleic acid soybeans were produced by combining mutant FAD2-1A and FAD2-1B genes. Despite having a high oleic acid content, the linolenic acid content of these soybeans was in the range of 4-6 %, which may be high enough to cause oxidative instability of the oil. Therefore, a study was conducted to incorporate one or two mutant FAD3 genes into the high oleic acid background to further reduce the linolenic acid content. As a result, soybean lines with high oleic acid and low linolenic acid (HOLL) content were produced using different sources of mutant FAD2-1A genes. While oleic acid content of these HOLL lines was stable across two testing environments, the reduction of linolenic acid content varied depending on the number of mutant FAD3 genes combined with mutant FAD2-1 genes, on the severity of mutation in the FAD2-1A gene, and on the testing environment. Combination of two mutant FAD2-1 genes and one mutant FAD3 gene resulted in less than 2 % linolenic acid content in Portageville, Missouri (MO) while four mutant genes were needed to achieve the same linolenic acid in Columbia, MO. This study generated non-transgenic soybeans with the highest oleic acid content and lowest linolenic acid content reported to date, offering a unique alternative to produce a fatty acid profile similar to olive oil.

Conferring high-temperature tolerance to nontransgenic tomato scions using graft transmission of RNA silencing of the fatty acid desaturase gene.

PubMed

Nakamura, Shinya; Hondo, Kana; Kawara, Tomoko; Okazaki, Yozo; Saito, Kazuki; Kobayashi, Kappei; Yaeno, Takashi; Yamaoka, Naoto; Nishiguchi, Masamichi

2016-02-01

We investigated graft transmission of high-temperature tolerance in tomato scions to nontransgenic scions from transgenic rootstocks, where the fatty acid desaturase gene (LeFAD7) was RNA-silenced. Tomato was transformed with a plasmid carrying an inverted repeat of LeFAD7 by Agrobacterium. Several transgenic lines showed the lower amounts of LeFAD7 RNA and unsaturated fatty acids, while nontransgenic control did not, and siRNA was detected in the transgenic lines, but not in control. These lines grew under conditions of high temperature, while nontransgenic control did not. Further, the nontransgenic plants were grafted onto the silenced transgenic plants. The scions showed less of the target gene RNA, and siRNA was detected. Under high-temperature conditions, these grafted plants grew, while control grafted plants did not. Thus, it was shown that high-temperature tolerance was conferred in the nontransgenic scions after grafting onto the silenced rootstocks. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yurchenko, Olga P.; Park, Sunjung; Ilut, Daniel C.

The majority of commercial cotton varieties planted worldwide are derived from Gossypium hirsutum, which is a naturally occurring allotetraploid produced by interspecific hybridization of A- and D-genome diploid progenitor species. While most cotton species are adapted to warm, semi-arid tropical and subtropical regions, and thus perform well in these geographical areas, cotton seedlings are sensitive to cold temperature, which can significantly reduce crop yields. One of the common biochemical responses of plants to cold temperatures is an increase in omega-3 fatty acids, which protects cellular function by maintaining membrane integrity. The purpose of our study was to identify and characterizemore » the omega-3 fatty acid desaturase (FAD) gene family in G. hirsutum, with an emphasis on identifying omega-3 FADs involved in cold temperature adaptation. Results: Eleven omega-3 FAD genes were identified in G. hirsutum, and characterization of the gene family in extant A and D diploid species ( G. herbaceum and G. raimondii, respectively) allowed for unambiguous genome assignment of all homoeologs in tetraploid G. hirsutum. The omega-3 FAD family of cotton includes five distinct genes, two of which encode endoplasmic reticulum-type enzymes ( FAD3-1 and FAD3-2) and three that encode chloroplast-type enzymes ( FAD7/8-1, FAD7/8-2, and FAD7/8-3). The FAD3-2 gene was duplicated in the A genome progenitor species after the evolutionary split from the D progenitor, but before the interspecific hybridization event that gave rise to modern tetraploid cotton. RNA-seq analysis revealed conserved, gene-specific expression patterns in various organs and cell types and semi-quantitative RT-PCR further revealed that FAD7/8-1 was specifically induced during cold temperature treatment of G. hirsutum seedlings. Conclusions: The omega-3 FAD gene family in cotton was characterized at the genome-wide level in three species, showing relatively ancient establishment of the gene family

Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium

DOE PAGES

Yurchenko, Olga P.; Park, Sunjung; Ilut, Daniel C.; ...

2014-11-18

The majority of commercial cotton varieties planted worldwide are derived from Gossypium hirsutum, which is a naturally occurring allotetraploid produced by interspecific hybridization of A- and D-genome diploid progenitor species. While most cotton species are adapted to warm, semi-arid tropical and subtropical regions, and thus perform well in these geographical areas, cotton seedlings are sensitive to cold temperature, which can significantly reduce crop yields. One of the common biochemical responses of plants to cold temperatures is an increase in omega-3 fatty acids, which protects cellular function by maintaining membrane integrity. The purpose of our study was to identify and characterizemore » the omega-3 fatty acid desaturase (FAD) gene family in G. hirsutum, with an emphasis on identifying omega-3 FADs involved in cold temperature adaptation. Results: Eleven omega-3 FAD genes were identified in G. hirsutum, and characterization of the gene family in extant A and D diploid species ( G. herbaceum and G. raimondii, respectively) allowed for unambiguous genome assignment of all homoeologs in tetraploid G. hirsutum. The omega-3 FAD family of cotton includes five distinct genes, two of which encode endoplasmic reticulum-type enzymes ( FAD3-1 and FAD3-2) and three that encode chloroplast-type enzymes ( FAD7/8-1, FAD7/8-2, and FAD7/8-3). The FAD3-2 gene was duplicated in the A genome progenitor species after the evolutionary split from the D progenitor, but before the interspecific hybridization event that gave rise to modern tetraploid cotton. RNA-seq analysis revealed conserved, gene-specific expression patterns in various organs and cell types and semi-quantitative RT-PCR further revealed that FAD7/8-1 was specifically induced during cold temperature treatment of G. hirsutum seedlings. Conclusions: The omega-3 FAD gene family in cotton was characterized at the genome-wide level in three species, showing relatively ancient establishment of the gene family

Cold affects the transcription of fatty acid desaturases and oil quality in the fruit of Olea europaea L. genotypes with different cold hardiness

PubMed Central

Matteucci, M.; D'Angeli, S.; Errico, S.; Lamanna, R.; Perrotta, G.; Altamura, M. M.

2011-01-01

The olive tree lacks dormancy and is low temperature sensitive, with differences in cold tolerance and oil quality among genotypes. The oil is produced in the drupe, and the unsaturated fatty acids contribute to its quality. The aim of the present research was to investigate the relationship among development, cold response, expression of fatty acid desaturase (FAD) genes, and unsaturated fatty acid composition in drupes belonging to genotypes differing in leaf cold tolerance, but producing good oil (i.e. the non-hardy Moraiolo, the semi-hardy Frantoio, and the hardy Canino). In all genotypes, cold sensitivity, evaluated by cold-induced transient increases in cytosolic calcium, was high in the epi-mesocarp cells before oil body formation, and decreased during oil biogenesis. However, genotype-dependent differences in cold sensitivity appeared at the end of oil production. Genotype-dependent differences in FAD2.1, FAD2.2, FAD6, and FAD7 expression levels occurred in the epi-mesocarp cells during the oleogenic period. However, FAD2.1 and FAD7 were always the highest in the first part of this period. FAD2.2 and FAD7 increased after cold applications during oleogenesis, independently of the genotype. Unsaturated fatty acids increased in the drupes of the non-hardy genotype, but not in those of the hardy one, after cold exposure at the time of the highest FAD transcription. The results show a direct relationship between FAD expression and lipid desaturation in the drupes of the cold-sensitive genotype, and an inverse relationship in those of the cold-resistant genotype, suggesting that drupe cold acclimation requires a fine FAD post-transcriptional regulation. Hypotheses relating FAD desaturation to storage and membrane lipids, and genotype cold hardiness are discussed. PMID:21357772

Mutant fatty acid desaturase and methods for directed mutagenesis

DOEpatents

Shanklin, John [Shoreham, NY; Whittle, Edward J [Greenport, NY

2008-01-29

The present invention relates to methods for producing fatty acid desaturase mutants having a substantially increased activity towards substrates with fewer than 18 carbon atom chains relative to an unmutagenized precursor desaturase having an 18 carbon chain length specificity, the sequences encoding the desaturases and to the desaturases that are produced by the methods. The present invention further relates to a method for altering a function of a protein, including a fatty acid desaturase, through directed mutagenesis involving identifying candidate amino acid residues, producing a library of mutants of the protein by simultaneously randomizing all amino acid candidates, and selecting for mutants which exhibit the desired alteration of function. Candidate amino acids are identified by a combination of methods. Enzymatic, binding, structural and other functions of proteins can be altered by the method.

Rapid, transient, and highly localized induction of plastidial ω-3 fatty acid desaturase mRNA at fungal infection sites in Petroselinum crispum

PubMed Central

Kirsch, Christoph; Takamiya-Wik, Monica; Reinold, Susanne; Hahlbrock, Klaus; Somssich, Imre E.

1997-01-01

Parsley (Petroselinum crispum) plants and suspension-cultured cells have been used extensively for studies of non-host-resistance mechanisms in plant/pathogen interactions. We now show that treatment of cultured parsley cells with a defined peptide elicitor of fungal origin causes rapid and large changes in the levels of various unsaturated fatty acids. While linoleic acid decreased and linolenic acid increased steadily for several hours, comparatively sharp increases in oleic acid followed a biphasic time course. In contrast, the overall level of stearic acid remained unaffected. Using a PCR-based approach, a parsley cDNA was isolated sharing high sequence similarity with ω-3 fatty acid desaturases. Subsequent isolation and characterization of a full-length cDNA enabled its functional identification as a plastid-localized ω-3 fatty acid desaturase by complementation of the Arabidopsis thaliana fad7/8 double mutant which is low in trienoic fatty acids. ω-3 Fatty acid desaturase mRNA accumulated rapidly and transiently in elicitor-treated cultured parsley cells, protoplasts, and leaves, as well as highly localized around fungal infection sites in parsley leaf buds. These results indicate that unsaturated fatty acid metabolism is yet another component of the highly complex, transcriptionally regulated pathogen defense response in plants. PMID:9050908

Total fatty acid content of the plasma membrane of Saccharomyces cerevisiae is more responsible for ethanol tolerance than the degree of unsaturation.

PubMed

Kim, Hyun-Soo; Kim, Na-Rae; Choi, Wonja

2011-03-01

The effect of change in unsaturated fatty acid composition on ethanol tolerance in Saccharomyces cerevisiae overexpressing ScOLE1 (∆9 fatty acid desaturase gene of S. cerevisiae), CaFAD2 (∆12 fatty acid desaturase gene of Candida albicans), or CaFAD3 (ω3 fatty acid desaturase gene of C. albicans) was examined. ScOLE1 over-expression increased the total unsaturated fatty acid content and enhanced ethanol tolerance, compared with a control strain. In contrast, overexpression of CaFAD2 and CaFAD3, which led to production of linoleic acid (18:2) and α-linolenic acid (18:3), respectively, neither changed total unsaturated fatty acids nor enhanced ethanol tolerance. The total unsaturated fatty acid content rather than the degree of unsaturation is thus an important factor for ethanol tolerance.

Cloning and functional expression of a cDNA encoding stearoyl-ACP Δ9-desaturase from the endosperm of coconut (Cocos nucifera L.).

PubMed

Gao, Lingchao; Sun, Ruhao; Liang, Yuanxue; Zhang, Mengdan; Zheng, Yusheng; Li, Dongdong

2014-10-01

Coconut (Cocos nucifera L.) is an economically tropical fruit tree with special fatty acid compositions. The stearoyl-acyl carrier protein (ACP) desaturase (SAD) plays a key role in the properties of the majority of cellular glycerolipids. In this paper, a full-length cDNA of a stearoyl-acyl carrier protein desaturase, designated CocoFAD, was isolated from cDNA library prepared from the endosperm of coconut (C. nucifera L.). An 1176 bp cDNA from overlapped PCR products containing ORF encoding a 391-amino acid (aa) protein was obtained. The coded protein was virtually identical and shared the homology to other Δ9-desaturase plant sequences (greater than 80% as similarity to that of Elaeis guineensis Jacq). The real-time fluorescent quantitative PCR result indicated that the yield of CocoFAD was the highest in the endosperm of 8-month-old coconut and leaf, and the yield was reduced to 50% of the highest level in the endosperm of 15-month-old coconut. The coding region showed heterologous expression in strain INVSc1 of yeast (Saccharomyces cerevisiae). GC-MS analysis showed that the levels of palmitoleic acid (16:1) and oleic acid (18:1) were improved significantly; meanwhile stearic acid (18:0) was reduced. These results indicated that the plastidial Δ9 desaturase from the endosperm of coconut was involved in the biosynthesis of hexadecenoic acid and octadecenoic acid, which was similar with other plants. These results may be valuable for understanding the mechanism of fatty acid metabolism and the genetic improvement of CocoFAD gene in palm plants in the future. Copyright © 2014 Elsevier B.V. All rights reserved.

A common FADS2 promoter polymorphism increases promoter activity and facilitates binding of transcription factor ELK1

PubMed Central

Lattka, E.; Eggers, S.; Moeller, G.; Heim, K.; Weber, M.; Mehta, D.; Prokisch, H.; Illig, T.; Adamski, J.

2010-01-01

Fatty acid desaturases (FADS) play an important role in the formation of omega-6 and omega-3 highly unsaturated fatty acids (HUFAs). The composition of HUFAs in the human metabolome is important for membrane fluidity and for the modulation of essential physiological functions such as inflammation processes and brain development. Several recent studies reported significant associations of single nucleotide polymorphisms (SNPs) in the human FADS gene cluster with HUFA levels and composition. The presence of the minor allele correlated with a decrease of desaturase reaction products and an accumulation of substrates. We performed functional studies with two of the associated polymorphisms (rs3834458 and rs968567) and showed an influence of polymorphism rs968567 on FADS2 promoter activity by luciferase reporter gene assays. Electrophoretic mobility shift assays proved allele-dependent DNA-binding ability of at least two protein complexes to the region containing SNP rs968567. One of the proteins binding to this region in an allele-specific manner was shown to be the transcription factor ELK1 (a member of ETS domain transcription factor family). These results indicate that rs968567 influences FADS2 transcription and offer first insights into the modulation of complex regulation mechanisms of FADS2 gene transcription by SNPs. PMID:19546342

A common FADS2 promoter polymorphism increases promoter activity and facilitates binding of transcription factor ELK1.

PubMed

Lattka, E; Eggers, S; Moeller, G; Heim, K; Weber, M; Mehta, D; Prokisch, H; Illig, T; Adamski, J

2010-01-01

Fatty acid desaturases (FADS) play an important role in the formation of omega-6 and omega-3 highly unsaturated fatty acids (HUFAs). The composition of HUFAs in the human metabolome is important for membrane fluidity and for the modulation of essential physiological functions such as inflammation processes and brain development. Several recent studies reported significant associations of single nucleotide polymorphisms (SNPs) in the human FADS gene cluster with HUFA levels and composition. The presence of the minor allele correlated with a decrease of desaturase reaction products and an accumulation of substrates. We performed functional studies with two of the associated polymorphisms (rs3834458 and rs968567) and showed an influence of polymorphism rs968567 on FADS2 promoter activity by luciferase reporter gene assays. Electrophoretic mobility shift assays proved allele-dependent DNA-binding ability of at least two protein complexes to the region containing SNP rs968567. One of the proteins binding to this region in an allele-specific manner was shown to be the transcription factor ELK1 (a member of ETS domain transcription factor family). These results indicate that rs968567 influences FADS2 transcription and offer first insights into the modulation of complex regulation mechanisms of FADS2 gene transcription by SNPs.

Associations between a fatty acid desaturase gene polymorphism and blood arachidonic acid compositions in Japanese elderly.

PubMed

Horiguchi, Sayaka; Nakayama, Kazuhiro; Iwamoto, Sadahiko; Ishijima, Akiko; Minezaki, Takayuki; Baba, Mamiko; Kontai, Yoshiko; Horikawa, Chika; Kawashima, Hiroshi; Shibata, Hiroshi; Kagawa, Yasuo; Kawabata, Terue

2016-02-01

We investigated whether the single nucleotide polymorphism rs174547 (T/C) of the fatty acid desaturase-1 gene, FADS1, is associated with changes in erythrocyte membrane and plasma phospholipid (PL) long-chain polyunsaturated fatty acid (LCPUFA) composition in elderly Japanese participants (n=124; 65 years or older; self-feeding and oral intake). The rs174547 C-allele carriers had significantly lower arachidonic acid (ARA; n-6 PUFA) and higher linoleic acid (LA, n-6 PUFA precursor) levels in erythrocyte membrane and plasma PL (15% and 6% ARA reduction, respectively, per C-allele), suggesting a low LA to ARA conversion rate in erythrocyte membrane and plasma PL of C-allele carriers. α-linolenic acid (n-3 PUFA precursor) levels were higher in the plasma PL of C-allele carriers, whereas levels of the n-3 LCPUFAs eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) were unchanged in erythrocyte membrane and plasma PL. Thus, rs174547 genotypes were significantly associated with different ARA compositions of the blood of elderly Japanese. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the Structure and Function of the Phytoene Desaturase CRTI from Pantoea ananatis, a Membrane-Peripheral and FAD-Dependent Oxidase/Isomerase

PubMed Central

Gemmecker, Sandra; Poussin-Courmontagne, Pierre; Mailliot, Justine; McEwen, Alastair G.; Ghisla, Sandro; Al-Babili, Salim; Cavarelli, Jean; Beyer, Peter

2012-01-01

CRTI-type phytoene desaturases prevailing in bacteria and fungi can form lycopene directly from phytoene while plants employ two distinct desaturases and two cis-tans isomerases for the same purpose. This property renders CRTI a valuable gene to engineer provitamin A-formation to help combat vitamin A malnutrition, such as with Golden Rice. To understand the biochemical processes involved, recombinant CRTI was produced and obtained in homogeneous form that shows high enzymatic activity with the lipophilic substrate phytoene contained in phosphatidyl-choline (PC) liposome membranes. The first crystal structure of apo-CRTI reveals that CRTI belongs to the flavoprotein superfamily comprising protoporphyrinogen IX oxidoreductase and monoamine oxidase. CRTI is a membrane-peripheral oxidoreductase which utilizes FAD as the sole redox-active cofactor. Oxygen, replaceable by quinones in its absence, is needed as the terminal electron acceptor. FAD, besides its catalytic role also displays a structural function by enabling the formation of enzymatically active CRTI membrane associates. Under anaerobic conditions the enzyme can act as a carotene cis-trans isomerase. In silico-docking experiments yielded information on substrate binding sites, potential catalytic residues and is in favor of single half-site recognition of the symmetrical C40 hydrocarbon substrate. PMID:22745782

Association of maternal weight with FADS and ELOVL genetic variants and fatty acid levels- The PREOBE follow-up

PubMed Central

de la Garza Puentes, Andrea; Montes Goyanes, Rosa; Chisaguano Tonato, Aida Maribel; Torres-Espínola, Francisco José; Arias García, Miriam; de Almeida, Leonor; Bonilla Aguirre, María; Guerendiain, Marcela; Castellote Bargalló, Ana Isabel; Segura Moreno, Maite; García-Valdés, Luz; Campoy, Cristina; Lopez-Sabater, M. Carmen

2017-01-01

Single nucleotide polymorphisms (SNPs) in the genes encoding the fatty acid desaturase (FADS) and elongase (ELOVL) enzymes affect long-chain polyunsaturated fatty acid (LC-PUFA) production. We aimed to determine if these SNPs are associated with body mass index (BMI) or affect fatty acids (FAs) in pregnant women. Participants (n = 180) from the PREOBE cohort were grouped according to pre-pregnancy BMI: normal-weight (BMI = 18.5–24.9, n = 88) and overweight/obese (BMI≥25, n = 92). Plasma samples were analyzed at 24 weeks of gestation to measure FA levels in the phospholipid fraction. Selected SNPs were genotyped (7 in FADS1, 5 in FADS2, 3 in ELOVL2 and 2 in ELOVL5). Minor allele carriers of rs174545, rs174546, rs174548 and rs174553 (FADS1), and rs1535 and rs174583 (FADS2) were nominally associated with an increased risk of having a BMI≥25. Only for the normal-weight group, minor allele carriers of rs174537, rs174545, rs174546, and rs174553 (FADS1) were negatively associated with AA:DGLA index. Normal-weight women who were minor allele carriers of FADS SNPs had lower levels of AA, AA:DGLA and AA:LA indexes, and higher levels of DGLA, compared to major homozygotes. Among minor allele carriers of FADS2 and ELOVL2 SNPs, overweight/obese women showed higher DHA:EPA index than the normal-weight group; however, they did not present higher DHA concentrations than the normal-weight women. In conclusion, minor allele carriers of FADS SNPs have an increased risk of obesity. Maternal weight changes the effect of genotype on FA levels. Only in the normal-weight group, minor allele carriers of FADS SNPs displayed reduced enzymatic activity and FA levels. This suggests that women with a BMI≥25 are less affected by FADS genetic variants in this regard. In the presence of FADS2 and ELOVL2 SNPs, overweight/obese women showed higher n-3 LC-PUFA production indexes than women with normal weight, but this was not enough to obtain a higher n-3 LC-PUFA concentration. PMID:28598979

Effects of tung oilseed FAD2 and DGAT2 genes on unsaturated fatty acid accumulation in Rhodotorula glutinis and Arabidopsis thaliana.

PubMed

Chen, Yicun; Cui, Qinqin; Xu, Yongjie; Yang, Susu; Gao, Ming; Wang, Yangdong

2015-08-01

Genetic engineering to produce valuable lipids containing unsaturated fatty acids (UFAs) holds great promise for food and industrial applications. Efforts to genetically modify plants to produce desirable UFAs with single enzymes, however, have had modest success. The key enzymes fatty acid desaturase (FAD) and diacylglycerol acyltransferase (DGAT) are responsible for UFA biosynthesis (a push process) and assembling fatty acids into lipids (a pull process) in plants, respectively. To examine their roles in UFA accumulation, VfFAD2 and VfDGAT2 genes cloned from Vernicia fordii (tung tree) oilseeds were conjugated and transformed into Rhodotorula glutinis and Arabidopsis thaliana via Agrobacterium tumefaciens. Real-time quantitative PCR revealed variable gene expression levels in the transformants, with a much higher level of VfDGAT2 than VfFAD2. The relationship between VfFAD2 expression and linoleic acid (C18:2) increases in R. glutinis (R (2) = 0.98) and A. thaliana (R (2) = 0.857) transformants was statistically linear. The VfDGAT2 expression level was statistically correlated with increased total fatty acid content in R. glutinis (R (2) = 0.962) and A. thaliana (R (2) = 0.8157) transformants. With a similar expression level between single- and two-gene transformants, VfFAD2-VfDGAT2 co-transformants showed a higher linolenic acid (C18:3) yield in R. glutinis (174.36 % increase) and A. thaliana (14.61 % increase), and eicosatrienoic acid (C20:3) was enriched (17.10 % increase) in A. thaliana. Our data suggest that VfFAD2-VfDGAT2 had a synergistic effect on UFA metabolism in R. glutinis, and to a lesser extent, A. thaliana. These results show promise for further genetic engineering of plant lipids to produce desirable UFAs.

Histone acetyltransferase general control non-repressed protein 5 (GCN5) affects the fatty acid composition of Arabidopsis thaliana seeds by acetylating fatty acid desaturase3 (FAD3).

PubMed

Wang, Tianya; Xing, Jiewen; Liu, Xinye; Liu, Zhenshan; Yao, Yingyin; Hu, Zhaorong; Peng, Huiru; Xin, Mingming; Zhou, Dao-Xiu; Zhang, Yirong; Ni, Zhongfu

2016-12-01

Seed oils are important natural resources used in the processing and preparation of food. Histone modifications represent key epigenetic mechanisms that regulate gene expression, plant growth and development. However, histone modification events during fatty acid (FA) biosynthesis are not well understood. Here, we demonstrate that a mutation of the histone acetyltransferase GCN5 can decrease the ratio of α-linolenic acid (ALA) to linoleic acid (LA) in seed oil. Using RNA-Seq and ChIP assays, we identified FAD3, LACS2, LPP3 and PLAIIIβ as the targets of GCN5. Notably, the GCN5-dependent H3K9/14 acetylation of FAD3 determined the expression levels of FAD3 in Arabidopsis thaliana seeds, and the ratio of ALA/LA in the gcn5 mutant was rescued to the wild-type levels through the overexpression of FAD3. The results of this study indicated that GCN5 modulated FA biosynthesis by affecting the acetylation levels of FAD3. We provide evidence that histone acetylation is involved in FA biosynthesis in Arabidopsis seeds and might contribute to the optimization of the nutritional structure of edible oils through epigenetic engineering. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Genetic and epigenetic transgenerational implications related to omega-3 fatty acids. Part II: maternal FADS2 rs174575 genotype and DNA methylation predict toddler cognitive performance.

PubMed

Cheatham, Carol L; Lupu, Daniel S; Niculescu, Mihai D

2015-11-01

Maternal transfer of fatty acids is important to fetal brain development. The prenatal environment may differentially affect the substrates supporting declarative memory abilities, as the level of fatty acids transferred across the placenta may be affected by the maternal fatty acid desaturase 2 (FADS2) rs174575 single nucleotide polymorphism. In this study, we hypothesized that toddler and maternal rs174575 genotype and FADS2 promoter methylation would be related to the toddlers' declarative memory performance. Seventy-one 16-month-old toddlers participated in an imitation paradigm designed to test immediate and long-term declarative memory abilities. FADS2 rs174575 genotype was determined and FADS2 promoter methylation was quantified from blood by bisulfite pyrosequencing for the toddlers and their natural mothers. Toddlers of GG mothers at the FADS2 rs174575 single nucleotide polymorphism did not perform as well on memory assessments as toddlers of CC or CG mothers when controlling for plasma α-linolenic acid and child genotype. Toddler methylation status was related to immediate memory performance, whereas maternal methylation status was related to delayed memory performance. Thus, prenatal experience and maternal FADS2 status have a pervasive, long-lasting influence on the brain development of the offspring, but as the postnatal environment becomes more primary, the offsprings' own biology begins to have an effect. Copyright © 2015 Elsevier Inc. All rights reserved.

Dietary adaptation of FADS genes in Europe varied across time and geography.

PubMed

Ye, Kaixiong; Gao, Feng; Wang, David; Bar-Yosef, Ofer; Keinan, Alon

2017-05-26

Fatty acid desaturase (FADS) genes encode rate-limiting enzymes for the biosynthesis of omega-6 and omega-3 long-chain polyunsaturated fatty acids (LCPUFAs). This biosynthesis is essential for individuals subsisting on LCPUFA-poor diets (for example, plant-based). Positive selection on FADS genes has been reported in multiple populations, but its cause and pattern in Europeans remain unknown. Here we demonstrate, using ancient and modern DNA, that positive selection acted on the same FADS variants both before and after the advent of farming in Europe, but on opposite (that is, alternative) alleles. Recent selection in farmers also varied geographically, with the strongest signal in southern Europe. These varying selection patterns concur with anthropological evidence of varying diets, and with the association of farming-adaptive alleles with higher FADS1 expression and thus enhanced LCPUFA biosynthesis. Genome-wide association studies reveal that farming-adaptive alleles not only increase LCPUFAs, but also affect other lipid levels and protect against several inflammatory diseases.

Temperature-dependent endogenous oxygen concentration regulates microsomal oleate desaturase in developing sunflower seeds.

PubMed

Rolletschek, Hardy; Borisjuk, Ljudmilla; Sánchez-García, Alicia; Gotor, Cecilia; Romero, Luis C; Martínez-Rivas, José M; Mancha, Manuel

2007-01-01

Oleoyl-phosphatidylcholine desaturase (FAD2) is a key enzyme involved in fatty acid desaturation in oilseeds, which is affected by environmental temperature. The results of this study show that FAD2 is regulated in vivo via temperature-dependent endogenous oxygen concentrations in developing sunflower (Helianthus annuus L.) seeds. By combining in vivo oxygen profiling, in situ hybridization of FAD2 genes, an assay of energy status, fatty acid analysis, and an in vitro FAD2 enzyme activity assay, it is shown that: (i) the oil-storing embryo is characterized by a very low oxygen level that is developmentally regulated. Oxygen supply is mainly limited by the thin seed coat. (ii) Elevations of external oxygen supply raised the energy status of seed and produced a dramatic increase of the FAD2 enzyme activity as well as the linoleic acid content. (iii) A clear negative correlation exists between temperature and internal oxygen concentration. The changes occurred almost instantly and the effect was fully reversible. The results indicate that the internal oxygen level acts as a key regulator for the activity of the FAD2 enzyme. It is concluded that a major mechanism by which temperature modifies the unsaturation degree of the sunflower oil is through its effect on dissolved oxygen levels in the developing seed.

A novel omega3-fatty acid desaturase involved in the biosynthesis of eicosapentaenoic acid.

PubMed Central

Pereira, Suzette L; Huang, Yung-Sheng; Bobik, Emil G; Kinney, Anthony J; Stecca, Kevin L; Packer, Jeremy C L; Mukerji, Pradip

2004-01-01

Long-chain n-3 PUFAs (polyunsaturated fatty acids) such as EPA (eicosapentaenoic acid; 20:5 n-3) have important therapeutic and nutritional benefits in humans. In plants, cyanobacteria and nematodes, omega3-desaturases catalyse the formation of these n-3 fatty acids from n-6 fatty acid precursors. Here we describe the isolation and characterization of a gene ( sdd17 ) derived from an EPA-rich fungus, Saprolegnia diclina, that encodes a novel omega3-desaturase. This gene was isolated by PCR amplification of an S. diclina cDNA library using oligonucleotide primers corresponding to conserved regions of known omega3-desaturases. Expression of this gene in Saccharomyces cerevisiae, in the presence of various fatty acid substrates, revealed that the recombinant protein could exclusively desaturate 20-carbon n-6 fatty acid substrates with a distinct preference for ARA (arachidonic acid; 20:4 n-6), converting it into EPA. This activity differs from that of the known omega3-desaturases from any organism. Plant and cyanobacterial omega3-desaturases exclusively desaturate 18-carbon n-6 PUFAs, and a Caenorhabditis elegans omega3-desaturase preferentially desaturated 18-carbon PUFAs over 20-carbon substrates, and could not convert ARA into EPA when expressed in yeast. The sdd17 -encoded desaturase was also functional in transgenic somatic soya bean embryos, resulting in the production of EPA from exogenously supplied ARA, thus demonstrating its potential for use in the production of EPA in transgenic oilseed crops. PMID:14651475

Exploration of the perceived and actual benefits of omega-3 fatty acids and the impact of FADS1 and FADS2 genetic information on dietary intake and blood levels of EPA and DHA.

PubMed

Roke, Kaitlin

2017-03-01

From a global health perspective, increased intake of omega-3 fatty acids (FAs), in particular eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are beneficial for human health. However, the consumption of EPA- and DHA-rich foods such as fatty fish is low in the Western diet. Therefore, finding new ways to motivate people to increase their consumption of omega-3 FAs is essential. To find effective ways to motivate individuals, understanding people's awareness of omega-3 FAs and how they obtain their knowledge about nutrition and health is critical. Consequently, we developed an online survey to assess awareness and self-reported intake of omega-3 FAs and supplements in young adults. EPA and DHA are also produced endogenously to a limited extent through a pathway regulated by fatty acid desaturase 1 and 2 (FADS1 and FADS2) genes. Of relevance, single nucleotide polymorphisms (SNPs) in the FADS genes influence levels of omega-3 FAs, where minor allele carriers have lower levels compared with major allele carriers. Accordingly, we conducted a clinical trial to investigate FA levels in response to dietary EPA and DHA supplementation in young adults stratified by SNPs in FADS1 and FADS2. The level of reported awareness of omega-3 terminology varied depending on an individual's field of study and thus providing all participants with the same set of nutrition information could be an effective tool to increase knowledge and motivate behaviour change. Additionally, the variation in FA levels in accordance to SNPs in FADS1 and FADS2 could be used to create tailored nutritional recommendations which may improve lifestyle habits. The results discovered in the first 2 studies regarding awareness of omega-3 FAs and genetic variation were subsequently used to design a nutrigenetics intervention in young adults. Individuals who received their FADS1 genetic information were more aware of different omega-3 FAs and reported fewer barriers to their consumption by the end of

FADS1 FADS2 Gene Cluster, PUFA Intake and Blood Lipids in Children: Results from the GINIplus and LISAplus Studies

PubMed Central

Standl, Marie; Lattka, Eva; Stach, Barbara; Koletzko, Sibylle; Bauer, Carl-Peter; von Berg, Andrea; Berdel, Dietrich; Krämer, Ursula; Schaaf, Beate; Röder, Stefan; Herbarth, Olf; Buyken, Anette; Drogies, Tim; Thiery, Joachim; Koletzko, Berthold; Heinrich, Joachim

2012-01-01

Background Elevated cholesterol levels in children can be a risk factor for cardiovascular diseases in later life. In adults, it has been shown that blood lipid levels are strongly influenced by polymorphisms in the fatty acid desaturase (FADS) gene cluster in addition to nutritional and other exogenous and endogenous determinants. Our aim was to investigate whether lipid levels are determined by the FADS genotype already in children and whether this association interacts with dietary intake of n-3 fatty acids. Methods The analysis was based on data of 2006 children from two German prospective birth cohort studies. Total cholesterol, HDL, LDL and triglycerides were measured at 10 years of age. Six single nucleotide polymorphisms (SNPs) of the FADS gene cluster were genotyped. Dietary n-3 fatty acid intake was assessed by food frequency questionnaire. Linear regression modeling was used to assess the association between lipid levels, n-3 fatty acid intake and FADS genotype. Results Individuals carrying the homozygous minor allele had lower levels of total cholesterol [means ratio (MR) ranging from 0.96 (p = 0.0093) to 0.98 (p = 0.2949), depending on SNPs] and LDL [MR between 0.94 (p = 0.0179) and 0.97 (p = 0.2963)] compared to homozygous major allele carriers. Carriers of the heterozygous allele showed lower HDL levels [β between −0.04 (p = 0.0074) to −0.01 (p = 0.3318)] and higher triglyceride levels [MR ranging from 1.06 (p = 0.0065) to 1.07 (p = 0.0028)] compared to homozygous major allele carriers. A higher n-3 PUFA intake was associated with higher concentrations of total cholesterol, LDL, HDL and lower triglyceride levels, but these associations did not interact with the FADS1 FADS2 genotype. Conclusion Total cholesterol, HDL, LDL and triglyceride concentrations may be influenced by the FADS1 FADS2 genotype already in 10 year old children. Genetically determined blood lipid levels during childhood might differentially

Genetic variation in polyunsaturated fatty acid metabolism and its potential relevance for human development and health.

PubMed

Glaser, Claudia; Lattka, Eva; Rzehak, Peter; Steer, Colin; Koletzko, Berthold

2011-04-01

Blood and tissue contents of polyunsaturated fatty acid (PUFA) and long-chain PUFA (LC-PUFA) are related to numerous health outcomes including cardiovascular health, allergies, mental health and cognitive development. Evidence has accumulated to show that in addition to diet, common polymorphisms in the fatty acid desaturase (FADS) gene cluster have very marked effects on human PUFA and LC-PUFA status. Recent results suggest that in addition to fatty acid desaturase 1 and fatty acid desaturase 2, the gene product of fatty acid desaturase 3 is associated with desaturating activity. New data have become available to show that FADS single nucleotide polymorphisms (SNPs) also modulate docosahexaenoic acid status in pregnancy as well as LC-PUFA levels in children and in human milk. There are indications that FADS SNPs modulate the risk for allergic disorders and eczema, and the effect of breastfeeding on later cognitive development. Mechanisms by which FADS SNPs modulate PUFA levels in blood, breast milk and tissues should be explored further. More studies are required to explore the effects of FADS gene variants in populations with different ethnic backgrounds, lifestyles and dietary habits, and to investigate in greater depth the interaction of gene variants, diet and clinical end points, including immune response and developmental outcomes. Analyses of FADS gene variants should be included into all sizeable cohort and intervention studies addressing biological effects of PUFA and LC-PUFA in order to consider these important confounders, and to enhance study sensitivity and precision. © 2011 Blackwell Publishing Ltd.

FADS1 genetic variability interacts with dietary α-linolenic acid intake to affect serum non-HDL-cholesterol concentrations in European adolescents.

PubMed

Dumont, Julie; Huybrechts, Inge; Spinneker, Andre; Gottrand, Frédéric; Grammatikaki, Evangelia; Bevilacqua, Noemi; Vyncke, Krishna; Widhalm, Kurt; Kafatos, Anthony; Molnar, Denes; Labayen, Idoia; Gonzalez-Gross, Marcela; Amouyel, Philippe; Moreno, Luis A; Meirhaeghe, Aline; Dallongeville, Jean

2011-07-01

Two rate-limiting enzymes in PUFA biosynthesis, Δ5- and Δ6-desaturases, are encoded by the FADS1 and FADS2 genes, respectively. Genetic variants in the FADS1-FADS2 gene cluster are associated with changes in plasma concentrations of PUFA, HDL- and LDL-cholesterol, and TG. However, little is known about whether dietary PUFA intake modulates these associations, especially in adolescents. We assessed whether dietary linoleic acid (LA) or α-linolenic acid (ALA) modulate the association between the FADS1 rs174546 polymorphism and concentrations of PUFA, other lipids, and lipoproteins in adolescents. Dietary intakes of LA and ALA, FADS1 rs174546 genotypes, PUFA levels in serum phospholipids, and serum concentrations of TG, cholesterol, and lipoproteins were determined in 573 European adolescents from the HELENA study. The sample was stratified according to the median dietary LA (≤9.4 and >9.4 g/d) and ALA (≤1.4 and >1.4 g/d) intakes. The associations between FADS1 rs174546 and concentrations of PUFA, TG, cholesterol, and lipoproteins were not affected by dietary LA intake (all P-interaction > 0.05). Similarly, the association between the FADS1 rs174546 polymorphism and serum phospholipid concentrations of ALA or EPA was not modified by dietary ALA intake (all P-interaction > 0.05). In contrast, the rs174546 minor allele was associated with lower total cholesterol concentrations (P = 0.01 under the dominant model) and non-HDL-cholesterol concentrations (P = 0.02 under the dominant model) in the high-ALA-intake group but not in the low-ALA-intake group (P-interaction = 0.01). These results suggest that dietary ALA intake modulates the association between FADS1 rs174546 and serum total and non-HDL-cholesterol concentrations at a young age.

ω3 fatty acid desaturases from microorganisms: structure, function, evolution, and biotechnological use.

PubMed

Wang, Mingxuan; Chen, Haiqin; Gu, Zhennan; Zhang, Hao; Chen, Wei; Chen, Yong Q

2013-12-01

The biosynthesis of very-long-chain polyunsaturated fatty acids involves an alternating process of fatty acid desaturation and elongation catalyzed by complex series of enzymes. ω3 desaturase plays an important role in converting ω6 fatty acids into ω3 fatty acids. Genes for this desaturase have been identified and characterized in a wide range of microorganisms, including cyanobacteria, yeasts, molds, and microalgae. Like all fatty acid desaturases, ω3 desaturase is structurally characterized by the presence of three highly conserved histidine-rich motifs; however, unlike some desaturases, it lacks a cytochrome b5-like domain. Understanding the structure, function, and evolution of ω3 desaturases, particularly their substrate specificities in the biosynthesis of very-long-chain polyunsaturated fatty acids, lays the foundation for potential production of various ω3 fatty acids in transgenic microorganisms.

Two Δ6-desaturase-like genes in common carp (Cyprinus carpio var. Jian): structure characterization, mRNA expression, temperature and nutritional regulation.

PubMed

Ren, Hong-tao; Zhang, Guang-qin; Li, Jian-lin; Tang, Yong-kai; Li, Hong-xia; Yu, Ju-hua; Xu, Pao

2013-08-01

Δ6-Desaturase is the rate-limiting enzyme involved in highly unsaturated fatty acid (HUFA) biosynthesis. There is very little information on the evolution and functional characterization of Δ6Fad-a and Δ6Fad-b in common carp (Cyprinus carpio var. Jian). In the present study, the genomic sequences and structures of two putative Δ6-desaturase-like genes in common carp genome were obtained. We investigated the mRNA expression patterns of Δ6Fad-a and Δ6Fad-b in tissue, hatching carp embryos, larvae by temperature shock and juveniles under nutritional regulation. Our results showed that the two Δ6Fad genes had identical coding exon structures, being comprised of 12 coding exons, and with introns of distinct size and sequence composition. They were not allelic variants of a single gene. Both Δ6Fad genes were highly expressed in liver, intestine (pyloric caeca) and brain. The Δ6Fad-a and Δ6Fad-b mRNAs showed an increase in expression from newly hatched to 25 days after hatching. The expression levels of Δ6Fad-a were obviously regulated by temperature, whereas Δ6Fad-b was not affected by temperature. The regulation of Δ6Fad-a and Δ6Fad-b in response to dietary fatty acid composition was determined in liver, brain and intestine (pyloric caeca) of common carp fed with diets: diet1with fish oil (FO) rich in n-3 HUFA, diet2 with corn oil (CO, 18:2n-6) and diet3 with linseed oil (LO, 18:3n-3). The differential expression of Δ6Fad-a and Δ6Fad-b genes in liver, brain and intestine in common carps was fed with different oil sources, respectively. Further work is in progress to determine the mechanism of differential expression of the Δ6Fad-a and Δ6Fad-b genes in different tissues and the roles of transcription factors in regulating HUFA synthesis. Copyright © 2013 Elsevier B.V. All rights reserved.

The role of FADS1/2 polymorphisms on cardiometabolic markers and fatty acid profiles in young adults consuming fish oil supplements.

PubMed

Roke, Kaitlin; Mutch, David M

2014-06-16

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-3 (n-3) fatty acids (FAs) known to influence cardiometabolic markers of health. Evidence suggests that single nucleotide polymorphisms (SNPs) in the fatty acid desaturase 1 and 2 (FADS1/2) gene cluster may influence an individual's response to n-3 FAs. This study examined the impact of a moderate daily dose of EPA and DHA fish oil supplements on cardiometabolic markers, FA levels in serum and red blood cells (RBC), and whether these endpoints were influenced by SNPs in FADS1/2. Young adults consumed fish oil supplements (1.8 g total EPA/DHA per day) for 12 weeks followed by an 8-week washout period. Serum and RBC FA profiles were analyzed every two weeks by gas chromatography. Two SNPs were genotyped: rs174537 in FADS1 and rs174576 in FADS2. Participants had significantly reduced levels of blood triglycerides (-13%) and glucose (-11%) by week 12; however, these benefits were lost during the washout period. EPA and DHA levels increased significantly in serum (+250% and +51%, respectively) and RBCs (+132% and +18%, respectively) within the first two weeks of supplementation and remained elevated throughout the 12-week period. EPA and DHA levels in RBCs only (not serum) remained significantly elevated (+37% and +24%, respectively) after the washout period. Minor allele carriers for both SNPs experienced greater increases in RBC EPA levels during supplementation; suggesting that genetic variation at this locus can influence an individual's response to fish oil supplements.

Functional analysis and tissue-differential expression of four FAD2 genes in amphidiploid Brassica napus derived from Brassica rapa and Brassica oleracea.

PubMed

Lee, Kyeong-Ryeol; In Sohn, Soo; Jung, Jin Hee; Kim, Sun Hee; Roh, Kyung Hee; Kim, Jong-Bum; Suh, Mi Chung; Kim, Hyun Uk

2013-12-01

Fatty acid desaturase 2 (FAD2), which resides in the endoplasmic reticulum (ER), plays a crucial role in producing linoleic acid (18:2) through catalyzing the desaturation of oleic acid (18:1) by double bond formation at the delta 12 position. FAD2 catalyzes the first step needed for the production of polyunsaturated fatty acids found in the glycerolipids of cell membranes and the triacylglycerols in seeds. In this study, four FAD2 genes from amphidiploid Brassica napus genome were isolated by PCR amplification, with their enzymatic functions predicted by sequence analysis of the cDNAs. Fatty acid analysis of budding yeast transformed with each of the FAD2 genes showed that whereas BnFAD2-1, BnFAD2-2, and BnFAD2-4 are functional enzymes, and BnFAD2-3 is nonfunctional. The four FAD2 genes of B. napus originated from synthetic hybridization of its diploid progenitors Brassica rapa and Brassica oleracea, each of which has two FAD2 genes identical to those of B. napus. The BnFAD2-3 gene of B. napus, a nonfunctional pseudogene mutated by multiple nucleotide deletions and insertions, was inherited from B. rapa. All BnFAD2 isozymes except BnFAD2-3 localized to the ER. Nonfunctional BnFAD2-3 localized to the nucleus and chloroplasts. Four BnFAD2 genes can be classified on the basis of their expression patterns. © 2013.

Genetic mapping of FAD2 genes and their relative contribution towards oil quality in peanut (Arachis hypogaea L.)

USDA-ARS?s Scientific Manuscript database

Improvement of oil quality is the major research objective in peanut because of its high economic impact on growers/traders and several health benefits to consumers. Fatty acid desaturase (FAD) genes are known to control quality traits but their position on the peanut genome and their relative contr...

Association between polymorphisms in the fatty acid desaturase gene cluster and the plasma triacylglycerol response to an n-3 PUFA supplementation.

PubMed

Cormier, Hubert; Rudkowska, Iwona; Paradis, Ann-Marie; Thifault, Elisabeth; Garneau, Véronique; Lemieux, Simone; Couture, Patrick; Vohl, Marie-Claude

2012-08-01

Eicosapentaenoic and docosahexaenoic acids have been reported to have a variety of beneficial effects on cardiovascular disease risk factors. However, a large inter-individual variability in the plasma lipid response to an omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation is observed in different studies. Genetic variations may influence plasma lipid responsiveness. The aim of the present study was to examine the effects of a supplementation with n-3 PUFA on the plasma lipid profile in relation to the presence of single-nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) gene cluster. A total of 208 subjects from Quebec City area were supplemented with 3 g/day of n-3 PUFA, during six weeks. In a statistical model including the effect of the genotype, the supplementation and the genotype by supplementation interaction, SNP rs174546 was significantly associated (p = 0.02) with plasma triglyceride (TG) levels, pre- and post-supplementation. The n-3 supplementation had an independent effect on plasma TG levels and no significant genotype by supplementation interaction effects were observed. In summary, our data support the notion that the FADS gene cluster is a major determinant of plasma TG levels. SNP rs174546 may be an important SNP associated with plasma TG levels and FADS1 gene expression independently of a nutritional intervention with n-3 PUFA.

Association between Polymorphisms in the Fatty Acid Desaturase Gene Cluster and the Plasma Triacylglycerol Response to an n-3 PUFA Supplementation

PubMed Central

Cormier, Hubert; Rudkowska, Iwona; Paradis, Ann-Marie; Thifault, Elisabeth; Garneau, Véronique; Lemieux, Simone; Couture, Patrick; Vohl, Marie-Claude

2012-01-01

Eicosapentaenoic and docosahexaenoic acids have been reported to have a variety of beneficial effects on cardiovascular disease risk factors. However, a large inter-individual variability in the plasma lipid response to an omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation is observed in different studies. Genetic variations may influence plasma lipid responsiveness. The aim of the present study was to examine the effects of a supplementation with n-3 PUFA on the plasma lipid profile in relation to the presence of single-nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) gene cluster. A total of 208 subjects from Quebec City area were supplemented with 3 g/day of n-3 PUFA, during six weeks. In a statistical model including the effect of the genotype, the supplementation and the genotype by supplementation interaction, SNP rs174546 was significantly associated (p = 0.02) with plasma triglyceride (TG) levels, pre- and post-supplementation. The n-3 supplementation had an independent effect on plasma TG levels and no significant genotype by supplementation interaction effects were observed. In summary, our data support the notion that the FADS gene cluster is a major determinant of plasma TG levels. SNP rs174546 may be an important SNP associated with plasma TG levels and FADS1 gene expression independently of a nutritional intervention with n-3 PUFA. PMID:23016130

Production of γ-linolenic acid and stearidonic acid by Synechococcus sp. PCC7002 containing cyanobacterial fatty acid desaturase genes

NASA Astrophysics Data System (ADS)

Dong, Xuewei; He, Qingfang; Peng, Zhenying; Yu, Jinhui; Bian, Fei; Li, Youzhi; Bi, Yuping

2016-07-01

Genetic modification is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. Synechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid (GLA) and stearidonic acid (SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6D, Syd15D and Syd6Dd15D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in Synechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.

Functional characterisation of two cytochrome b5-fusion desaturases from Anemone leveillei: the unexpected identification of a fatty acid Delta6-desaturase.

PubMed

Whitney, Heather M; Michaelson, Louise V; Sayanova, Olga; Pickett, John A; Napier, Johnathan A

2003-10-01

The Ranunculaceae are known to accumulate a wide range of unusual fatty acids in their seed lipids, and this variability has been advocated as a taxonomic marker. The Anemone species, Anemone leveillei L. and Anemone rivularis Buch.-Ham., have previously been reported to accumulate Delta5-desaturated fatty acids in their seed tissue [K. Aitzetmüller (1995) Plant Syst Evol 9:229-240]. Two cDNAs, AL1 and AL2, with similarity to plant cytochrome b5-fusion "front-end" desaturases were isolated from developing seeds of A. leveillei and their function identified by expression in Saccharomyces cerevisiae. AL2 was characterised as a sphingolipid long-chain-base Delta8-desaturase, while AL1 acted as a fatty acid desaturase. However, AL1 did not produce Delta5-desaturated fatty acids as expected; instead, when expressed in transgenic S. cerevisiae or Arabidopsis thaliana this enzyme was functionally characterised as a Delta6-desaturase. Northern analysis confirmed the expression of this gene in seed tissue and leaf tissue of A. leveillei, though Delta6-desaturated fatty acids were found to accumulate only in the leaf tissue. The unexpected characterisation of a Delta6-desaturase in A. leveillei has implications for the use of fatty acids in chemotaxonomic studies. This is also the first report of a higher-plant Delta6-desaturase from a family other than the Boraginaceae.

Identification and Analysis of a Gene from Calendula officinalis Encoding a Fatty Acid Conjugase

PubMed Central

Qiu, Xiao; Reed, Darwin W.; Hong, Haiping; MacKenzie, Samuel L.; Covello, Patrick S.

2001-01-01

Two homologous cDNAs, CoFad2 and CoFac2, were isolated from a Calendula officinalis developing seed by a polymerase chain reaction-based cloning strategy. Both sequences share similarity to FAD2 desaturases and FAD2-related enzymes. In C. officinalis plants CoFad2 was expressed in all tissues tested, whereas CoFac2 expression was specific to developing seeds. Expression of CoFad2 cDNA in yeast (Saccharomyces cerevisiae) indicated it encodes a Δ12 desaturase that introduces a double bond at the 12 position of 16:1(9Z) and 18:1(9Z). Expression of CoFac2 in yeast revealed that the encoded enzyme acts as a fatty acid conjugase converting 18:2(9Z, 12Z) to calendic acid 18:3(8E, 10E, 12Z). The enzyme also has weak activity on the mono-unsaturates 16:1(9Z) and 18:1(9Z) producing compounds with the properties of 8,10 conjugated dienes. PMID:11161042

Identification of Delta5-fatty acid desaturase from the cellular slime mold dictyostelium discoideum.

PubMed

Saito, T; Ochiai, H

1999-10-01

cDNA fragments putatively encoding amino acid sequences characteristic of the fatty acid desaturase were obtained using expressed sequence tag (EST) information of the Dictyostelium cDNA project. Using this sequence, we have determined the cDNA sequence and genomic sequence of a desaturase. The cloned cDNA is 1489 nucleotides long and the deduced amino acid sequence comprised 464 amino acid residues containing an N-terminal cytochrome b5 domain. The whole sequence was 38.6% identical to the initially identified Delta5-desaturase of Mortierella alpina. We have confirmed its function as Delta5-desaturase by over expression mutation in D. discoideum and also the gain of function mutation in the yeast Saccharomyces cerevisiae. Analysis of the lipids from transformed D. discoideum and yeast demonstrated the accumulation of Delta5-desaturated products. This is the first report concering fatty acid desaturase in cellular slime molds.

Genetic Variants of the FADS Gene Cluster and ELOVL Gene Family, Colostrums LC-PUFA Levels, Breastfeeding, and Child Cognition

PubMed Central

Morales, Eva; Bustamante, Mariona; Gonzalez, Juan Ramon; Guxens, Monica; Torrent, Maties; Mendez, Michelle; Garcia-Esteban, Raquel; Julvez, Jordi; Forns, Joan; Vrijheid, Martine; Molto-Puigmarti, Carolina; Lopez-Sabater, Carmen; Estivill, Xavier; Sunyer, Jordi

2011-01-01

Introduction Breastfeeding effects on cognition are attributed to long-chain polyunsaturated fatty acids (LC-PUFAs), but controversy persists. Genetic variation in fatty acid desaturase (FADS) and elongase (ELOVL) enzymes has been overlooked when studying the effects of LC-PUFAs supply on cognition. We aimed to: 1) to determine whether maternal genetic variants in the FADS cluster and ELOVL genes contribute to differences in LC-PUFA levels in colostrum; 2) to analyze whether these maternal variants are related to child cognition; and 3) to assess whether children's variants modify breastfeeding effects on cognition. Methods Data come from two population-based birth cohorts (n = 400 mother-child pairs from INMA-Sabadell; and n = 340 children from INMA-Menorca). LC-PUFAs were measured in 270 colostrum samples from INMA-Sabadell. Tag SNPs were genotyped both in mothers and children (13 in the FADS cluster, 6 in ELOVL2, and 7 in ELOVL5). Child cognition was assessed at 14 mo and 4 y using the Bayley Scales of Infant Development and the McCarthy Scales of Children's Abilities, respectively. Results Children of mothers carrying genetic variants associated with lower FADS1 activity (regulating AA and EPA synthesis), higher FADS2 activity (regulating DHA synthesis), and with higher EPA/AA and DHA/AA ratios in colostrum showed a significant advantage in cognition at 14 mo (3.5 to 5.3 points). Not being breastfed conferred an 8- to 9-point disadvantage in cognition among children GG homozygote for rs174468 (low FADS1 activity) but not among those with the A allele. Moreover, not being breastfed resulted in a disadvantage in cognition (5 to 8 points) among children CC homozygote for rs2397142 (low ELOVL5 activity), but not among those carrying the G allele. Conclusion Genetically determined maternal supplies of LC-PUFAs during pregnancy and lactation appear to be crucial for child cognition. Breastfeeding effects on cognition are modified by child genetic variation in

ALA10, a Phospholipid Flippase, Controls FAD2/FAD3 Desaturation of Phosphatidylcholine in the ER and Affects Chloroplast Lipid Composition in Arabidopsis thaliana1

PubMed Central

Sautron, Emeline; Boudiere, Laurence; Michaud, Morgane; Dubots, Emmanuelle; Albrieux, Catherine; Marechal, Eric; Jouhet, Juliette

2016-01-01

The biogenesis of photosynthetic membranes relies on galactoglycerolipids, which are synthesized via pathways that are dispatched over several cell compartments. This membrane biogenesis requires both trafficking of lipid intermediates and a tight homeostatic regulation. In this work, we address the role of ALA10 (for aminophospholipid ATPase), a P4-type ATPase, in a process counteracting the monogalactosyldiacylglycerol (MGDG) shortage in Arabidopsis (Arabidopsis thaliana) leaves. ALA10 can interact with protein partners, ALIS1 (for ALA-interacting subunit1) or ALIS5, leading to differential endomembrane localizations of the interacting proteins, close to the plasma membrane with ALIS1 or to chloroplasts with ALIS5. ALA10 interacts also with FATTY ACID DESATURASE2 (FAD2), and modification of ALA10 expression affects phosphatidylcholine (PC) fatty acyl desaturation by disturbing the balance between FAD2 and FAD3 activities. Modulation of ALA10 expression downstream impacts the fatty acyl composition of chloroplast PC. ALA10 expression also enhances leaf growth and improves the MGDG-PC ratio, possibly through MGDG SYNTHASE1 (MGD1) activation by phosphatidic acid. The positive effect of ALA10 on leaf development is significant in conditions such as upon treatment of plants with Galvestine-1, an inhibitor of MGDG synthases, or when plants are grown at chilling temperature. PMID:26620528

Evaluating Changes in Omega-3 Fatty Acid Intake after Receiving Personal FADS1 Genetic Information: A Randomized Nutrigenetic Intervention

PubMed Central

Roke, Kaitlin; Walton, Kathryn; Klingel, Shannon L.; Harnett, Amber; Subedi, Sanjeena; Haines, Jess; Mutch, David M.

2017-01-01

Nutrigenetics research is anticipated to lay the foundation for personalized dietary recommendations; however, it remains unclear if providing individuals with their personal genetic information changes dietary behaviors. Our objective was to evaluate if providing information for a common variant in the fatty acid desaturase 1 (FADS1) gene changed omega-3 fatty acid (FA) intake and blood levels in young female adults (18–25 years). Participants were randomized into Genetic (intervention) and Non-Genetic (control) groups, with measurements taken at Baseline and Final (12 weeks). Dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was assessed using an omega-3 food frequency questionnaire. Red blood cell (RBC) FA content was quantified by gas chromatography. Implications of participation in a nutrigenetics study and awareness of omega-3 FAs were assessed with online questionnaires. Upon completion of the study, EPA and DHA intake increased significantly (p = 1.0 × 10−4) in all participants. This change was reflected by small increases in RBC %EPA. Participants in the Genetic group showed increased awareness of omega-3 terminology by the end of the study, reported that the dietary recommendations were more useful, and rated cost as a barrier to omega-3 consumption less often than those in the Non-Genetic group. Providing participants FADS1 genetic information did not appear to influence omega-3 intake during the 12 weeks, but did change perceptions and behaviors related to omega-3 FAs in this timeframe. PMID:28272299

Evaluating Changes in Omega-3 Fatty Acid Intake after Receiving Personal FADS1 Genetic Information: A Randomized Nutrigenetic Intervention.

PubMed

Roke, Kaitlin; Walton, Kathryn; Klingel, Shannon L; Harnett, Amber; Subedi, Sanjeena; Haines, Jess; Mutch, David M

2017-03-06

Nutrigenetics research is anticipated to lay the foundation for personalized dietary recommendations; however, it remains unclear if providing individuals with their personal genetic information changes dietary behaviors. Our objective was to evaluate if providing information for a common variant in the fatty acid desaturase 1 ( FADS1 ) gene changed omega-3 fatty acid (FA) intake and blood levels in young female adults (18-25 years). Participants were randomized into Genetic (intervention) and Non-Genetic (control) groups, with measurements taken at Baseline and Final (12 weeks). Dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was assessed using an omega-3 food frequency questionnaire. Red blood cell (RBC) FA content was quantified by gas chromatography. Implications of participation in a nutrigenetics study and awareness of omega-3 FAs were assessed with online questionnaires. Upon completion of the study, EPA and DHA intake increased significantly ( p = 1.0 × 10 -4 ) in all participants. This change was reflected by small increases in RBC %EPA. Participants in the Genetic group showed increased awareness of omega-3 terminology by the end of the study, reported that the dietary recommendations were more useful, and rated cost as a barrier to omega-3 consumption less often than those in the Non-Genetic group. Providing participants FADS1 genetic information did not appear to influence omega-3 intake during the 12 weeks, but did change perceptions and behaviors related to omega-3 FAs in this timeframe.

Modified Acyl-ACP desaturase

DOEpatents

Cahoon, Edgar B.; Shanklin, John; Lindqvist, Ylva; Schneider, Gunter

1999-03-30

Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity.

Modified acyl-ACP desaturase

DOEpatents

Cahoon, Edgar B.; Shanklin, John; Lindgvist, Ylva; Schneider, Gunter

1998-01-06

Disclosed is a methods for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity.

Newly identified essential amino acid residues affecting ^8-sphingolipid desaturase activity revealed by site-directed mutagenesis

USDA-ARS?s Scientific Manuscript database

In order to identify amino acid residues crucial for the enzymatic activity of ^8-sphingolipid desaturases, a sequence comparison was performed among ^8-sphingolipid desaturases and ^6-fatty acid desaturase from various plants. In addition to the known conserved cytb5 (cytochrome b5) HPGG motif and...

Modified acyl-ACP desaturase

DOEpatents

Cahoon, E.B.; Shanklin, J.; Lindgvist, Y.; Schneider, G.

1998-01-06

Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity. 1 fig.

Modified Acyl-ACP desaturase

DOEpatents

Cahoon, E.B.; Shanklin, J.; Lindqvist, Y.; Schneider, G.

1999-03-30

Disclosed is a method for modifying the chain length and double bond positional specificities of a soluble plant fatty acid desaturase. More specifically, the method involves modifying amino acid contact residues in the substrate binding channel of the soluble fatty acid desaturase which contact the fatty acid. Specifically disclosed is the modification of an acyl-ACP desaturase. Amino acid contact residues which lie within the substrate binding channel are identified, and subsequently replaced with different residues to effect the modification of activity. 2 figs.

Identification of a Δ5-like fatty acyl desaturase from the cephalopod Octopus vulgaris (Cuvier 1797) involved in the biosynthesis of essential fatty acids.

PubMed

Monroig, Oscar; Navarro, Juan C; Dick, James R; Alemany, Frederic; Tocher, Douglas R

2012-08-01

Long-chain polyunsaturated fatty acids (LC-PUFA) have been identified as essential compounds for common octopus (Octopus vulgaris), but precise dietary requirements have not been determined due, in part, to the inherent difficulties of performing feeding trials on paralarvae. Our objective is to establish the essential fatty acid (EFA) requirements for paralarval stages of the common octopus through characterisation of the enzymes of endogenous LC-PUFA biosynthetic pathways. In this study, we isolated a cDNA with high homology to fatty acyl desaturases (Fad). Functional characterisation in recombinant yeast showed that the octopus Fad exhibited Δ5-desaturation activity towards saturated and polyunsaturated fatty acyl substrates. Thus, it efficiently converted the yeast's endogenous 16:0 and 18:0 to 16:1n-11 and 18:1n-13, respectively, and desaturated exogenously added PUFA substrates 20:4n-3 and 20:3n-6 to 20:5n-3 (EPA) and 20:4n-6 (ARA), respectively. Although the Δ5 Fad enables common octopus to produce EPA and ARA, the low availability of its adequate substrates 20:4n-3 and 20:3n-6, either in the diet or by limited endogenous synthesis from C(18) PUFA, might indicate that EPA and ARA are indeed EFA for this species. Interestingly, the octopus Δ5 Fad can also participate in the biosynthesis of non-methylene-interrupted FA, PUFA that are generally uncommon in vertebrates but have been found previously in marine invertebrates, including molluscs, and now also confirmed to be present in specific tissues of common octopus.

Polyunsaturated fatty acid levels in blood during pregnancy, at birth and at 7 years: their associations with two common FADS2 polymorphisms.

PubMed

Steer, Colin D; Hibbeln, Joseph R; Golding, Jean; Davey Smith, George

2012-04-01

Minor alleles of polymorphisms in the fatty acid desaturase (FADS) gene cluster have been associated with reduced desaturation of the precursor polyunsaturated fatty acids (FAs) in small studies. The effects of these polymorphisms during progressive developmental stages have not previously been reported. Data from blood samples for 4342 pregnant women, 3343 umbilical cords reflecting the newborn's blood supply and 5240 children aged 7 years were analysed to investigate the associations of polyunsaturated FAs with rs1535 and rs174575-two polymorphisms in the FADS2 gene. Strong positive associations were observed between the minor G allele for these two markers, especially rs1535, and the substrates linoleic (18:2n-6) and α-linolenic (18:3n-3) acid. Negative associations were observed for the more highly unsaturated FAs such as arachidonic acid (20:4n-6), timnodonic acid (EPA, 20:5n-3) and cervonic acid (DHA, 22:6n-3). Bivariable genetic associations using the mother and child genotypes suggested that the newborn metabolism had a greater capacity to synthesize the more highly unsaturated omega-6 FAs than the more highly unsaturated omega-3 FAs. Nevertheless, despite the immaturity of the neonate, there was evidence that synthesis of DHA was occurring. However, by 7 years, no associations were observed with the maternal genotype. This suggested that the children's FA levels were related only to their own metabolism with no apparent lasting influences of the in utero environment.

Effects of saturated and unsaturated fatty acids on estimated desaturase activities during a controlled dietary intervention.

PubMed

Warensjö, Eva; Risérus, Ulf; Gustafsson, Inga-Britt; Mohsen, Rawya; Cederholm, Tommy; Vessby, Bengt

2008-12-01

Direct measurement of desaturase activities are difficult to obtain in humans. Consequently, surrogate measures of desaturase activity (estimated desaturase activities) have been frequently used in observational studies, and estimated Delta(9)- (or stearoyl-CoA-desaturase (SCD)), Delta(6)- and Delta(5)-desaturase activities have been associated with cardiometabolic disease. Data on how the markers of desaturase activities are modified by changes in dietary fat quality are lacking and therefore warrant examination. In a two-period (three weeks) strictly controlled cross-over study, 20 subjects (six women and 14 men) consumed a diet high in saturated fat (SAT-diet) and a rapeseed oil diet (RO-diet), rich in oleic acid (OA), linoleic acid (LA) and alpha-linolenic acid (ALA). Estimated desaturase activities were calculated as precursor to product FA ratios in serum cholesteryl esters and phospholipids. The estimated SCD [16:1 n-7/16:0] and Delta(6)-desaturase [20:3 n-6/18:2 n-6] was significantly higher while Delta(5)-desaturase [20:4 n-6/20:3 n-6] was significantly lower in the SAT-diet (P<0.001 for all), compared to the RO-diet. The serum proportions of palmitic, stearic, palmitoleic and dihomo-gamma-linolenic acids were significantly higher in the SAT-diet while the proportions of LA and ALA were significantly higher in the RO-diet. This is the first study to demonstrate that surrogate measures of desaturase activities change as a consequence of an alteration in dietary fat quality. Both the [16:1/16:0]-ratio and 16:1 seem to reflect changes in saturated fat intake and may be useful markers of saturated fat intake in Western countries.

Expression of a coriander desaturase results in petroselinic acid production in transgenic tobacco

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cahoon, E.B.; Shanklin, J.; Ohlrogge, J.B.

1992-12-01

Little is known about the metabolic origin of petroselinic acid (18:1[Delta][sup 6cis]), the principal fatty acid of the seed oil of most Umbelliferae, Araliaceae, and Garryaceae species. To examine the possibility that petroselinic acid is the product of an acyl-acyl carrier protein (ACP) desaturase, Western blots of coriander and other Umbelliferae seed extracts were probed with antibodies against the [Delta][sup 9]-stearoyl-ACP desaturase of avocado. In these extracts, proteins of 39 and 36 kDa were detected. Of these, only the 36-kDa peptide was specific to tissues which synthesize petroselinic acid. A cDNA encoding the 36-kDa peptide was isolated from a coriandermore » endosperm cDNA library, placed under control of the cauliflower mosaic virus 35S promoter, and introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. Expression of this cDNA in transgenic tobacco callus was accompanied by the accumulation of petroselinic acid and [Delta][sup 4]-hexadecenoic acid, both of which were absent from control callus. These results demonstrate the involvement of a 36-kDa putative acyl-ACP desaturase in the biosynthetic pathway of petroselinic acid and the ability to produce fatty acids of unusual structure in transgenic plants by the expression of the gene for this desaturase. 27 refs., 5 figs.« less

Regulation of hepatic fatty acid elongase and desaturase expression in diabetes and obesity

PubMed Central

Wang, Yun; Botolin, Daniela; Xu, Jinghua; Christian, Barbara; Mitchell, Ernestine; Jayaprakasam, Bolleddula; Nair, Muraleedharan; Peters, Jeffery M.; Busik, Julia; Olson, L. Karl; Jump, Donald B.

2009-01-01

Fatty acid elongases and desaturases play an important role in hepatic and whole body lipid composition. We examined the role that key transcription factors played in the control of hepatic elongase and desaturase expression. Studies with peroxisome proliferator-activated receptor α (PPARα)-deficient mice establish that PPARα was required for WY14643-mediated induction of fatty acid elongase-5 (Elovl-5), Elovl-6, and all three desaturases [Δ5 desaturase (Δ5D), Δ6D, and Δ9D]. Increased nuclear sterol-regulatory element binding protein-1 (SREBP-1) correlated with enhanced expression of Elovl-6, Δ5D, Δ6D, and Δ9D. Only Δ9D was also regulated independently by liver X receptor (LXR) agonist. Glucose induction of L-type pyruvate kinase, Δ9D, and Elovl-6 expression required the carbohydrate-regulatory element binding protein/MAX-like factor X (ChREBP/MLX) heterodimer. Suppression of Elovl-6 and Δ9D expression in livers of streptozotocin-induced diabetic rats and high fat-fed glucose-intolerant mice correlated with low levels of nuclear SREBP-1. In leptin-deficient obese mice (Lepob/ob), increased SREBP-1 and MLX nuclear content correlated with the induction of Elovl-5, Elovl-6, and Δ9D expression and the massive accumulation of monoun-saturated fatty acids (18:1,n-7 and 18:1,n-9) in neutral lipids. Diabetes- and obesity-induced changes in hepatic lipid composition correlated with changes in elongase and desaturase expression. In conclusion, these studies establish a role for PPARα, LXR, SREBP-1, ChREBP, and MLX in the control of hepatic fatty acid elongase and desaturase expression and lipid composition. PMID:16790840

Cloning and characterization of unusual fatty acid desaturases from Anemone leveillei: identification of an acyl-coenzyme A C20 Delta5-desaturase responsible for the synthesis of sciadonic acid.

PubMed

Sayanova, Olga; Haslam, Richard; Venegas Caleron, Monica; Napier, Johnathan A

2007-05-01

The seed oil of Anemone leveillei contains significant amounts of sciadonic acid (20:3Delta(5,11,14); SA), an unusual non-methylene-interrupted fatty acid with pharmaceutical potential similar to arachidonic acid. Two candidate cDNAs (AL10 and AL21) for the C(20) Delta(5cis)-desaturase from developing seeds of A. leveillei were functionally characterized in transgenic Arabidopsis (Arabidopsis thaliana) plants. The open reading frames of both Delta(5)-desaturases showed some similarity to presumptive acyl-coenzyme A (CoA) desaturases found in animals and plants. When expressed in transgenic Arabidopsis, AL21 showed a broad range of substrate specificity, utilizing both saturated (16:0 and 18:0) and unsaturated (18:2, n-6 and 18:3, n-3) substrates. In contrast, AL10 did not show any activity in wild-type Arabidopsis. Coexpression of AL10 or AL21 with a C(18) Delta(9)-elongase in transgenic Arabidopsis plants resulted in the production of SA and juniperonic fatty acid (20:4Delta(5,11,14,17)). Thus, AL10 acted only on C(20) polyunsaturated fatty acids in a manner analogous to "front-end" desaturases. However, neither AL10 nor AL21 contain the cytochrome b(5) domain normally present in this class of enzymes. Acyl-CoA profiling of transgenic Arabidopsis plants and developing A. leveillei seeds revealed significant accumulation of Delta(5)-unsaturated fatty acids as acyl-CoAs compared to the accumulation of these fatty acids in total lipids. Positional analysis of triacylglycerols of A. leveillei seeds showed that Delta(5)-desaturated fatty acids were present in both sn-2 and sn-1 + sn-3 positions, although the majority of 16:1Delta(5), 18:1Delta(5), and SA was present at the sn-2 position. Our data provide biochemical evidence for the A. leveillei Delta(5)-desaturases using acyl-CoA substrates.

Cloning and Characterization of Unusual Fatty Acid Desaturases from Anemone leveillei: Identification of an Acyl-Coenzyme A C20 Δ5-Desaturase Responsible for the Synthesis of Sciadonic Acid1

PubMed Central

Sayanova, Olga; Haslam, Richard; Venegas Caleron, Monica; Napier, Johnathan A.

2007-01-01

The seed oil of Anemone leveillei contains significant amounts of sciadonic acid (20:3Δ5,11,14; SA), an unusual non-methylene-interrupted fatty acid with pharmaceutical potential similar to arachidonic acid. Two candidate cDNAs (AL10 and AL21) for the C20 Δ5cis-desaturase from developing seeds of A. leveillei were functionally characterized in transgenic Arabidopsis (Arabidopsis thaliana) plants. The open reading frames of both Δ5-desaturases showed some similarity to presumptive acyl-coenzyme A (CoA) desaturases found in animals and plants. When expressed in transgenic Arabidopsis, AL21 showed a broad range of substrate specificity, utilizing both saturated (16:0 and 18:0) and unsaturated (18:2, n-6 and 18:3, n-3) substrates. In contrast, AL10 did not show any activity in wild-type Arabidopsis. Coexpression of AL10 or AL21 with a C18 Δ9-elongase in transgenic Arabidopsis plants resulted in the production of SA and juniperonic fatty acid (20:4Δ5,11,14,17). Thus, AL10 acted only on C20 polyunsaturated fatty acids in a manner analogous to “front-end” desaturases. However, neither AL10 nor AL21 contain the cytochrome b5 domain normally present in this class of enzymes. Acyl-CoA profiling of transgenic Arabidopsis plants and developing A. leveillei seeds revealed significant accumulation of Δ5-unsaturated fatty acids as acyl-CoAs compared to the accumulation of these fatty acids in total lipids. Positional analysis of triacylglycerols of A. leveillei seeds showed that Δ5-desaturated fatty acids were present in both sn-2 and sn-1 + sn-3 positions, although the majority of 16:1Δ5, 18:1Δ5, and SA was present at the sn-2 position. Our data provide biochemical evidence for the A. leveillei Δ5-desaturases using acyl-CoA substrates. PMID:17384161

Dietary fish oil replacement by linseed oil: Effect on growth, nutrient utilization, tissue fatty acid composition and desaturase gene expression in silver barb (Puntius gonionotus) fingerlings.

PubMed

Nayak, Madhusmita; Saha, Ashis; Pradhan, Avinash; Samanta, Mrinal; Giri, Shiba Shankar

2017-03-01

Silver barb (Puntius gonionotus) is considered a promising medium carp species for freshwater aquaculture in Asia. This study in silver barb was carried out to evaluate the effects of total or partial substitution of dietary fish oil (FO) with linseed oil (LO) on growth, nutrient utilization, whole-body composition, muscle and liver fatty acid composition. Fish (12.1±0.4g of initial body weight) were fed for 60days with five experimental iso-proteinous, iso-lipidic and iso-caloric diets in which FO (control diet) was replaced by 33.3%, 50%, 66.7% and 100% LO. Final weight, weight gain, percent weight gain, SGR decreased linearly (p<0.001) with increasing LO levels in the diets. Dietary LO substitution levels did not significantly (p>0.05) affect the feed conversion ratio (FCR), protein efficiency ratio (PER) and whole body proximate composition. Furthermore, enhanced level of LO increased α-linolenic acid (ALA; 18:3n3) and linoleic acid (LA; 18:2n6) and decreased eicosapentaenoic acid (EPA; 20:5n3) and docosahexaenoic acid (DHA; 22:6n3) in muscle and liver. To understand the molecular mechanism of long chain-polyunsaturated fatty acid (LC-PUFA) biosynthesis, we cloned and characterized the fatty acyl Δ6 desaturase (Δ6 fad) cDNA and investigated its expression in various organs/tissues following replacement of FO with LO in the diet. The full-length Δ6 fad cDNA was 2056bp encoding 444 amino acids and was widely expressed in various organs/tissues. Replacement of FO with LO increased the expression of Δ6 fad mRNA in liver, muscle and intestine but no significant difference was found in the brain. Copyright © 2016 Elsevier Inc. All rights reserved.

Functional screening of a novel Δ15 fatty acid desaturase from the coccolithophorid Emiliania huxleyi.

PubMed

Kotajima, Tomonori; Shiraiwa, Yoshihiro; Suzuki, Iwane

2014-10-01

The coccolithophorid Emiliania huxleyi is a bloom-forming marine phytoplankton thought to play a key role as a biological pump that transfers carbon from the surface to the bottom of the ocean, thus contributing to the global carbon cycle. This alga is also known to accumulate a variety of polyunsaturated fatty acids. At 25°C, E. huxleyi produces mainly 14:0, 18:4n-3, 18:5n-3 and 22:6n-3. When the cells were transferred from 25°C to 15°C, the amount of unsaturated fatty acids, i.e. 18:1n-9, 18:3n-3 and 18:5n-3, gradually increased. Among the predicted desaturase genes whose expression levels were up-regulated at low temperature, we identified a gene encoding novel ∆15 fatty acid desaturase, EhDES15, involved in the production of n-3 polyunsaturated fatty acids in E. huxleyi. This desaturase contains a putative transit sequence for localization in chloroplasts and a ∆6 desaturase-like domain, but it does not contain a cytochrome b5 domain nor typical His-boxes found in ∆15 desaturases. Heterologous expression of EhDES15 cDNA in cyanobacterium Synechocystis sp. PCC 6803 cells increased the level of n-3 fatty acid species, which are produced at low levels in wild-type cells grown at 30°C. The orthologous genes are only conserved in the genomes of prasinophytes and cryptophytes. The His-boxes conserved in orthologues varied from that of the canonical ∆15 desaturases. These results suggested the gene encodes a novel ∆15 desaturase responsible for the synthesis of 18:3n-3 from 18:2n-6 in E. huxleyi. Copyright © 2014 Elsevier B.V. All rights reserved.

Predicting fatty acid profiles in blood based on food intake and the FADS1 rs174546 SNP.

PubMed

Hallmann, Jacqueline; Kolossa, Silvia; Gedrich, Kurt; Celis-Morales, Carlos; Forster, Hannah; O'Donovan, Clare B; Woolhead, Clara; Macready, Anna L; Fallaize, Rosalind; Marsaux, Cyril F M; Lambrinou, Christina-Paulina; Mavrogianni, Christina; Moschonis, George; Navas-Carretero, Santiago; San-Cristobal, Rodrigo; Godlewska, Magdalena; Surwiłło, Agnieszka; Mathers, John C; Gibney, Eileen R; Brennan, Lorraine; Walsh, Marianne C; Lovegrove, Julie A; Saris, Wim H M; Manios, Yannis; Martinez, Jose Alfredo; Traczyk, Iwona; Gibney, Michael J; Daniel, Hannelore

2015-12-01

A high intake of n-3 PUFA provides health benefits via changes in the n-6/n-3 ratio in blood. In addition to such dietary PUFAs, variants in the fatty acid desaturase 1 (FADS1) gene are also associated with altered PUFA profiles. We used mathematical modeling to predict levels of PUFA in whole blood, based on multiple hypothesis testing and bootstrapped LASSO selected food items, anthropometric and lifestyle factors, and the rs174546 genotypes in FADS1 from 1607 participants (Food4Me Study). The models were developed using data from the first reported time point (training set) and their predictive power was evaluated using data from the last reported time point (test set). Among other food items, fish, pizza, chicken, and cereals were identified as being associated with the PUFA profiles. Using these food items and the rs174546 genotypes as predictors, models explained 26-43% of the variability in PUFA concentrations in the training set and 22-33% in the test set. Selecting food items using multiple hypothesis testing is a valuable contribution to determine predictors, as our models' predictive power is higher compared to analogue studies. As unique feature, we additionally confirmed our models' power based on a test set. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intake levels of dietary long-chain PUFAs modify the association between genetic variation in FADS and LDL-C.

PubMed

Hellstrand, S; Sonestedt, E; Ericson, U; Gullberg, B; Wirfält, E; Hedblad, B; Orho-Melander, M

2012-06-01

Polymorphisms of the FA desaturase (FADS) gene cluster have been associated with LDL, HDL, and triglyceride concentrations. Because FADS converts α-linolenic acid (ALA) and linoleic acid into PUFAs, we investigated the interaction between different PUFA intakes and the FADS polymorphism rs174547 (T>C) on fasting blood lipid and lipoprotein concentrations. We included 4,635 individuals (60% females, 45-68 years) from the Swedish population-based Malmö Diet and Cancer cohort. Dietary intakes were assessed by a modified diet history method including 7-day registration of cooked meals. The C-allele of rs174547 was associated with lower LDL concentration (P = 0.03). We observed significant interaction between rs174547 and long-chain ω-3 PUFA intakes on LDL (P = 0.01); the C-allele was only associated with lower LDL among individuals in the lowest tertile of long-chain ω-3 PUFA intakes (P < 0.001). In addition, significant interaction was observed between rs174547 and the ratio of ALA and linoleic FA intakes on HDL (P = 0.03). However, no significant associations between the C-allele and HDL were detected within the intake tertiles of the ratio. Our findings suggest that dietary intake levels of different PUFAs modify the associated effect of genetic variation in FADS on LDL and HDL.

INHIBITION OF FATTY ACID DESATURASES IN Drosophila melanogaster LARVAE BLOCKS FEEDING AND DEVELOPMENTAL PROGRESSION.

PubMed

Wang, Yiwen; da Cruz, Tina Correia; Pulfemuller, Alicia; Grégoire, Stéphane; Ferveur, Jean-François; Moussian, Bernard

2016-05-01

Fatty acid desaturases are metabolic setscrews. To study their systemic impact on growth in Drosophila melanogaster, we inhibited fatty acid desaturases using the inhibitor CAY10566. As expected, the amount of desaturated lipids is reduced in larvae fed with CAY10566. These animals cease feeding soon after hatching, and their growth is strongly attenuated. A starvation program is not launched, but the expression of distinct metabolic genes is activated, possibly to mobilize storage material. Without attaining the normal size, inhibitor-fed larvae molt to the next stage indicating that the steroid hormone ecdysone triggers molting correctly. Nevertheless, after molting, expression of ecdysone-dependent regulators is not induced. While control larvae molt a second time, these larvae fail to do so and die after few days of straying. These effects are similar to those observed in experiments using larvae deficient for the fatty acid desaturase1 gene. Based on these data, we propose that the ratio of saturated to unsaturated fatty acids adjusts a sensor system that directs feeding behavior. We also hypothesize that loss of fatty acid desaturase activity leads to a block of the genetic program of development progression indirectly by switching on a metabolic compensation program. © 2016 Wiley Periodicals, Inc.

The role of a FADS1 polymorphism in the association of fatty acid blood levels, BMI and blood pressure in young children—Analyses based on path models

PubMed Central

Dering, Carmen; Siani, Alfonso; Russo, Paola; Kaprio, Jaakko; Risé, Patrizia; Moreno, Luis A.; De Henauw, Stefaan; Mehlig, Kirsten; Veidebaum, Toomas; Molnár, Denés; Tornaritis, Michael; Iacoviello, Licia; Pitsiladis, Yannis; Foraita, Ronja; Börnhorst, Claudia

2017-01-01

Background The recent obesity epidemic in children also showed an increase in the prevalence of hypertension. As blood pressure (BP) is associated with (long-chain) polyunsaturated fatty acids (LC PUFA), genetic variation in desaturase enzymes being involved in the synthesis of LC PUFA may be associated with BP. This study aimed to investigate the direct effects (independent of mediating variables) and indirect effects (mediated through intermediate variables) of a common variant in the FADS1 gene, rs174546, known to affect delta-5 desaturase (D5D) activity on PUFA level, body mass index (BMI) and BP. Methods A subsample of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) baseline survey including 520 children aged 2 to <10 years from six European countries was included. The association between rs174546 (Tacid, DGLA; arachidonic acid, ARA; eicosapentaenoic acid, EPA) or estimated D5D activity (D5D index) and BMI z-score were investigated through path model analyses, adjusting for sex, age, educational level of parents, family history of hypertension, lifestyle factors and blood levels of saturated and monounsaturated fatty acids, triglycerides and low density lipoprotein cholesterol. Whole blood fatty acids were measured by a validated gas chromatographic method and recorded as percentage of weight of all fatty acids detected. Results Minor allele carriers of the SNP rs174546 had significantly higher DGLA and lower ARA and EPA levels as well as a lower D5D index. Via ARA and BMI z-score, the polymorphism had an indirect lowering effect on systolic BP z-score for each additional T allele (standardized effect estimate -0.057, p = 0.007). For DGLA, EPA and D5D index, the indirect effects of rs174546 on systolic BP were also negative but did not reach significance. DGLA and EPA had an increasing

The role of a FADS1 polymorphism in the association of fatty acid blood levels, BMI and blood pressure in young children-Analyses based on path models.

PubMed

Wolters, Maike; Dering, Carmen; Siani, Alfonso; Russo, Paola; Kaprio, Jaakko; Risé, Patrizia; Moreno, Luis A; De Henauw, Stefaan; Mehlig, Kirsten; Veidebaum, Toomas; Molnár, Denés; Tornaritis, Michael; Iacoviello, Licia; Pitsiladis, Yannis; Galli, Claudio; Foraita, Ronja; Börnhorst, Claudia

2017-01-01

The recent obesity epidemic in children also showed an increase in the prevalence of hypertension. As blood pressure (BP) is associated with (long-chain) polyunsaturated fatty acids (LC PUFA), genetic variation in desaturase enzymes being involved in the synthesis of LC PUFA may be associated with BP. This study aimed to investigate the direct effects (independent of mediating variables) and indirect effects (mediated through intermediate variables) of a common variant in the FADS1 gene, rs174546, known to affect delta-5 desaturase (D5D) activity on PUFA level, body mass index (BMI) and BP. A subsample of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) baseline survey including 520 children aged 2 to <10 years from six European countries was included. The association between rs174546 (Tacid, DGLA; arachidonic acid, ARA; eicosapentaenoic acid, EPA) or estimated D5D activity (D5D index) and BMI z-score were investigated through path model analyses, adjusting for sex, age, educational level of parents, family history of hypertension, lifestyle factors and blood levels of saturated and monounsaturated fatty acids, triglycerides and low density lipoprotein cholesterol. Whole blood fatty acids were measured by a validated gas chromatographic method and recorded as percentage of weight of all fatty acids detected. Minor allele carriers of the SNP rs174546 had significantly higher DGLA and lower ARA and EPA levels as well as a lower D5D index. Via ARA and BMI z-score, the polymorphism had an indirect lowering effect on systolic BP z-score for each additional T allele (standardized effect estimate -0.057, p = 0.007). For DGLA, EPA and D5D index, the indirect effects of rs174546 on systolic BP were also negative but did not reach significance. DGLA and EPA had an increasing indirect effect on systolic BP

Biosynthesis of 10,12-dienoic fatty acids by a bifunctional Delta11 desaturase in Spodoptera littoralis.

PubMed

Serra, Montserrat; Piña, Benjami; Bujons, Jordi; Camps, Francisco; Fabriàs, Gemma

2006-08-01

In the biosynthetic pathway of Spodoptera littoralis sex pheromone, (E,E)-10,12-tetradecadienoic acid is produced from (Z)-11-tetradecenoic acid by desaturation and concomitant migration of the precursor double bond. With the aim of identifying the enzyme involved in this biotransformation, yeast Deltaelo1/Deltaole mutants, which are both elongase 1 and Delta9 desaturase-deficient, were transformed with the S. littoralis Delta11 desaturase gene using a Cu+2 inducible expression vector. The transformants produced a recombinant polyhistidine-tagged Delta11 desaturase that could be detected by immunoblotting from cell lysates. Lipid analysis revealed that besides producing large quantities of C11-monounsaturated fatty acids, mainly (Z)-11-hexadecenoic acid, (E,E)-10,12-tetradecadienoic acid and minor amounts of (E,Z)-10,12-hexadecadienoic acid were also produced, as well as very low quantities of another tetradecadienoate, which was tentatively identified as the (E,Z)-10,12-tetradecadienoic isomer. None of these dienes was detected with the Delta11 desaturase gene of Trichoplusia ni, which does not produce conjugated dienes as pheromone components. We conclude that the Delta11 desaturase of S. littoralis is a bifunctional enzyme with both Delta11 and Delta10,12 desaturation activities. The relationship between the substrate structure and the stereochemical outcome of the reaction is discussed.

Development of low-linolenic acid Brassica oleracea lines through seed mutagenesis and molecular characterization of mutants.

PubMed

Rahman, Habibur; Singer, Stacy D; Weselake, Randall J

2013-06-01

Designing the fatty acid composition of Brassica napus L. seed oil for specific applications would extend the value of this crop. A mutation in Fatty Acid Desaturase 3 (FAD3), which encodes the desaturase responsible for catalyzing the formation of α-linolenic acid (ALA; 18:3 (cisΔ9,12,15)), in a diploid Brassica species would potentially result in useful germplasm for creating an amphidiploid displaying low ALA content in the seed oil. For this, seeds of B. oleracea (CC), one of the progenitor species of B. napus, were treated with ethyl-methane-sulfonate to induce mutations in genes encoding enzymes involved in fatty acid biosynthesis. Seeds from 1,430 M2 plants were analyzed, from which M3 seed families with 5.7-6.9 % ALA were obtained. Progeny testing and selection for low ALA content were carried out in M3-M7 generations, from which mutant lines with <2.0 % ALA were obtained. Molecular analysis revealed that the mutation was due to a single nucleotide substitution from G to A in exon 3 of FAD3, which corresponds to an amino acid residue substitution from glutamic acid to lysine. No obvious differences in the expression of the FAD3 gene were detected between wild type and mutant lines; however, evaluation of the performance of recombinant Δ-15 desaturase from mutant lines in yeast indicated reduced production of ALA. The novelty of this mutation can be inferred from the position of the point mutation in the C-genome FAD3 gene when compared to the position of mutations reported previously by other researchers. This B. oleracea mutant line has the potential to be used for the development of low-ALA B. napus and B. carinata oilseed crops.

Alternation of plasma fatty acids composition and desaturase activities in children with liver steatosis

PubMed Central

Su, Hui-Min; Yao, Tsung-Chieh; Kuo, Ming-Ling; Lai, Ming-Wei; Tsai, Ming-Han; Huang, Jing-Long

2017-01-01

Objective The aim of this study was to investigate changes in plasma fatty acids proportions and estimated desaturase activities for variable grading of liver steatosis in children. Methods In total, 111 schoolchildren (aged 8–18 years) were included in the analysis from March 2015 to August 2016. Anthropometric evaluation, liver ultrasound examination and scoring for nonalcoholic fatty liver disease (NAFLD score = 0–6), and biochemical and plasma fatty acids analysis were performed. We compared the composition ratio of fatty acids between children with high-grade liver steatosis (NAFLD score = 4–6), low-grade liver steatosis (NAFLD score = 1–3), and healthy controls (NAFLD score = 0). In addition, correlation coefficients (r) between NAFLD score, metabolic variables, and estimated activity of desaturase indices (stearoyl-coenzyme A desaturase-1 (SCD1), delta-5 and delta-6 desaturase) were calculated. Results Compared with healthy controls, children with liver steatosis showed a higher proportion of monounsaturated fatty acids (21.16 ± 2.81% vs. 19.68 ± 2.71%, p = 0.024). In addition, children with high- grade liver steatosis exhibited higher proportions of palmitic acid (C16:0), palmitoleic acid (C16:1n-7), dihomo-γ-linolenic acid (C20:3n-6), adrenic acid (C22:4n-6), and docosapentaenoic acid (C22:5n-6); and lower proportions of eicosapentaenoic acid (C20:5n-3) (P< 0.05). In all subjects, the NAFLD score was positively correlated with body mass index (BMI) (kg/m2) (r = 0.696), homeostasis model of assessment ratio–index (HOMA-IR) (r = 0.510), SCD1(16) (r = 0.273), and the delta-6 index (r = 0.494); and inversely associated with the delta-5 index (r = -0.443). Conclusion Our current data suggested that children with liver steatosis was highly associated with obesity, and insulin resistance. In addition, increased endogenous lipogenesis through altered desaturase activity may contribute to the progression of liver steatosis in children. PMID:28759573

Supplementation with N-3 Long-Chain Polyunsaturated Fatty Acids or Olive Oil in Men and Women with Renal Disease Induces Differential Changes in the DNA Methylation of FADS2 and ELOVL5 in Peripheral Blood Mononuclear Cells

PubMed Central

Hoile, Samuel P.; Clarke-Harris, Rebecca; Huang, Rae-Chi; Calder, Philip C.; Mori, Trevor A.; Beilin, Lawrence J.; Lillycrop, Karen A.; Burdge, Graham C.

2014-01-01

Background Studies in animal models and in cultured cells have shown that fatty acids can induce alterations in the DNA methylation of specific genes. There have been no studies of the effects of fatty acid supplementation on the epigenetic regulation of genes in adult humans. Methods and Results We investigated the effect of supplementing renal patients with 4 g daily of either n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) or olive oil (OO) for 8 weeks on the methylation status of individual CpG loci in the 5′ regulatory region of genes involved in PUFA biosynthesis in peripheral blood mononuclear cells from men and women (aged 53 to 63 years). OO and n-3 LCPUFA each altered (>10% difference in methylation) 2/22 fatty acid desaturase (FADS)-2 CpGs, while n-3 LCPUFA, but not OO, altered (>10%) 1/12 ELOVL5 CpGs in men. OO altered (>6%) 8/22 FADS2 CpGs and (>3%) 3/12 elongase (ELOVL)-5 CpGs, while n-3 LCPUFA altered (>5%) 3/22 FADS2 CpGs and 2/12 (>3%) ELOVL5 CpGs in women. FADS1 or ELOVL2 methylation was unchanged. The n-3 PUFA supplementation findings were replicated in blood DNA from healthy adults (aged 23 to 30 years). The methylation status of the altered CpGs in FADS2 and ELOVL5 was associated negatively with the level of their transcripts. Conclusions These findings show that modest fatty acid supplementation can induce altered methylation of specific CpG loci in adult humans, contingent on the nature of the supplement and on sex. This has implications for understanding the effect of fatty acids on PUFA metabolism and cell function. PMID:25329159

Modulation of FadR Binding Capacity for Acyl-CoA Fatty Acids Through Structure-Guided Mutagenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bacik, John-Paul; Yeager, Chris M.; Twary, Scott N.

FadR is a versatile global regulator in Escherichia coli that controls fatty acid metabolism and thereby modulates the ability of this bacterium to grow using fatty acids or acetate as the sole carbon source. FadR regulates fatty acid metabolism in response to intra-cellular concentrations of acyl-CoA lipids. The ability of FadR to bind acyl-CoA fatty acids is hence of significant interest for the engineering of biosynthetic pathways for the production of lipid-based biofuels and commodity chemicals. Based on the available crystal structure of E. coli bound to myristoyl- CoA, we predicted amino acid positions within the effector binding pocket thatmore » would alter the ability of FadR to bind acyl-CoA fatty acids without affecting DNA binding. We utilized fluorescence polarization to characterize the in-vitro binding properties of wild type and mutant FadR. We found that a Leu102Ala mutant enhanced binding of the effector, likely by increasing the size of the binding pocket for the acyl moiety of the molecule. Conversely, the elimination of the guanidine side chain (Arg213Ala and Arg213Met mutants) of the CoA moiety binding site severely diminished the ability of FadR to bind the acyl-CoA effector. These results demonstrate the ability to fine tune FadR binding capacity. The validation of an efficient method to fully characterize all the binding events involved in the specific activity (effector and DNA operator binding) of FadR has allowed us to increase our understanding of the role of specific amino acids in the binding and recognition of acyl-CoA fatty acids and will greatly facilitate efforts aimed at engineering tunable FadR regulators for synthetic biology.« less

Modulation of FadR Binding Capacity for Acyl-CoA Fatty Acids Through Structure-Guided Mutagenesis

DOE PAGES

Bacik, John-Paul; Yeager, Chris M.; Twary, Scott N.; ...

2015-09-18

FadR is a versatile global regulator in Escherichia coli that controls fatty acid metabolism and thereby modulates the ability of this bacterium to grow using fatty acids or acetate as the sole carbon source. FadR regulates fatty acid metabolism in response to intra-cellular concentrations of acyl-CoA lipids. The ability of FadR to bind acyl-CoA fatty acids is hence of significant interest for the engineering of biosynthetic pathways for the production of lipid-based biofuels and commodity chemicals. Based on the available crystal structure of E. coli bound to myristoyl- CoA, we predicted amino acid positions within the effector binding pocket thatmore » would alter the ability of FadR to bind acyl-CoA fatty acids without affecting DNA binding. We utilized fluorescence polarization to characterize the in-vitro binding properties of wild type and mutant FadR. We found that a Leu102Ala mutant enhanced binding of the effector, likely by increasing the size of the binding pocket for the acyl moiety of the molecule. Conversely, the elimination of the guanidine side chain (Arg213Ala and Arg213Met mutants) of the CoA moiety binding site severely diminished the ability of FadR to bind the acyl-CoA effector. These results demonstrate the ability to fine tune FadR binding capacity. The validation of an efficient method to fully characterize all the binding events involved in the specific activity (effector and DNA operator binding) of FadR has allowed us to increase our understanding of the role of specific amino acids in the binding and recognition of acyl-CoA fatty acids and will greatly facilitate efforts aimed at engineering tunable FadR regulators for synthetic biology.« less

Improved γ-linolenic acid production in Mucor circinelloides by homologous overexpressing of delta-12 and delta-6 desaturases.

PubMed

Zhang, Yao; Luan, Xiao; Zhang, Huaiyuan; Garre, Victoriano; Song, Yuanda; Ratledge, Colin

2017-06-21

γ-Linolenic acid (GLA) is important because of its nutritional value and medicinal applications. Although the biosynthetic pathways of some plant and microbial GLA have been deciphered, current understanding of the correlation between desaturases and GLA synthesis in oleaginous fungi is incomplete. In previous work, we found that a large amount of oleic acid (OA) had not been converted to linoleic acid (LA) or GLA in Mucor circinelloides CBS 277.49, which may be due to inadequate activities of the delta-12 or delta-6 desaturases, and thus leading to the accumulation of OA and LA. Thus, it is necessary to explore the main contributing factor during the process of GLA biosynthesis in M. circinelloides. To enhance GLA production in M. circinelloides, homologous overexpression of delta-12 and two delta-6 desaturases (named delta-6-1 and delta-6-2, respectively) were analyzed. When delta-6 desaturase were overexpressed in M. circinelloides, up to 43% GLA was produced in the total fatty acids, and the yield of GLA reached 180 mg/l, which were, respectively, 38 and 33% higher than the control strain. These findings revealed that delta-6 desaturase (especially for delta-6-1 desaturase) plays an important role in GLA synthesis by M. circinelloides. The strain overexpressing delta-6-1 desaturase may have potential application in microbial GLA production.

RNAi trigger fragment truncation attenuates soybean FAD2-1 transcript suppression and yields intermediate oil phenotypes.

PubMed

Wagner, Nicholas; Mroczka, Andrew; Roberts, Peter D; Schreckengost, William; Voelker, Toni

2011-09-01

Suppression of the microsomal ω6 oleate desaturase during the seed development of soybean (Glycine max) with the 420-bp soybean FAD2-1A intron as RNAi trigger shifts the conventional fatty acid composition of soybean oil from 20% oleic and 60% polyunsaturates to one containing greater than 80% oleic acid and less than 10% polyunsaturates. To determine whether RNAi could be attenuated by reducing the trigger fragment length, transgenic plants were generated to express successively shorter 5' or 3' deletion derivatives of the FAD2-1A intron. We observed a gradual reduction in transcript suppression with shorter trigger fragments. Fatty acid composition was less affected with shorter triggers, and triggers less than 60 bp had no phenotypic effect. No trigger sequences conferring significantly higher or lower suppression efficiencies were found, and the primary determinant of suppression effect was sequence length. The observed relationship of transcript suppression with the induced fatty acid phenotype indicates that RNAi is a saturation process and not a step change between suppressed and nonsuppressed states and intermediate suppression states can be achieved. © 2010 Monsanto. Plant Biotechnology Journal © 2010 Society for Experimental Biology and Blackwell Publishing Ltd.

Changes in fatty acid composition in plant tissues expressing a mammalian delta9 desaturase.

PubMed

Moon, H; Hazebroek, J; Hildebrand, D F

2000-05-01

Plant tissues expressing a mammalian stearoyl-CoA delta9 desaturase were reported to accumulate delta9 hexadecenoic acid (16:1), normally very minor in most plant tissues. The transgenic plants were thoroughly analyzed for alterations of individual lipids in different subcellular sites. Western blot analysis indicated that the animal desaturase was targeted to the microsomes. The delta9 16:1 was incorporated into both the sn-1 and sn-2 positions of all the major membrane lipids tested, indicating that the endoplasmic reticulum acyltransferases do not exclude unsaturated C16 fatty acids from the sn-2 position. In addition to increases in monounsaturated and decreases in saturated fatty acids, accumulation of 16:1 was accompanied by a reduction in 18:3 in all the lipids tested except phosphatidylglycerol, and increases in 18:2 in phospholipids. Total C16 fatty acid content in the galactolipids of the transgenics was significantly higher than that in the control, but those in the phospholipids were unchanged. In transgenics, delta11 18:1 was detected in the sn-1 position of the lipids tested except phosphatidylinositol and phosphatidylserine. Introduction of the animal desaturase, controlled by a seed-specific phaseolin promoter, into soybean somatic embryo resulted in a significant reduction in saturated fatty acids. Such effects were greater in cotyledons than hypocotyl-radicles. This study demonstrated that the animal desaturase can be used to decrease the levels of saturated fatty acids in a crop plant.

Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress.

PubMed

Simón, María Victoria; Agnolazza, Daniela L; German, Olga Lorena; Garelli, Andrés; Politi, Luis E; Agbaga, Martin-Paul; Anderson, Robert E; Rotstein, Nora P

2016-03-01

Oxidative stress is involved in activating photoreceptor death in several retinal degenerations. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in the retina, protects cultured retina photoreceptors from apoptosis induced by oxidative stress and promotes photoreceptor differentiation. Here, we investigated whether eicosapentaenoic acid (EPA), a metabolic precursor to DHA, had similar effects and whether retinal neurons could metabolize EPA to DHA. Adding EPA to rat retina neuronal cultures increased opsin expression and protected photoreceptors from apoptosis induced by the oxidants paraquat and hydrogen peroxide (H2 O2 ). Palmitic, oleic, and arachidonic acids had no protective effect, showing the specificity for DHA. We found that EPA supplementation significantly increased DHA percentage in retinal neurons, but not EPA percentage. Photoreceptors and glial cells expressed Δ6 desaturase (FADS2), which introduces the last double bond in DHA biosynthetic pathway. Pre-treatment of neuronal cultures with CP-24879 hydrochloride, a Δ5/Δ6 desaturase inhibitor, prevented EPA-induced increase in DHA percentage and completely blocked EPA protection and its effect on photoreceptor differentiation. These results suggest that EPA promoted photoreceptor differentiation and rescued photoreceptors from oxidative stress-induced apoptosis through its elongation and desaturation to DHA. Our data show, for the first time, that isolated retinal neurons can synthesize DHA in culture. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in retina photoreceptors, and its precursor, eicosapentaenoic acid (EPA) have multiple beneficial effects. Here, we show that retina neurons in vitro express the desaturase FADS2 and can synthesize DHA from EPA. Moreover, addition of EPA to these cultures protects photoreceptors from oxidative stress and promotes their differentiation through its metabolization to DHA. © 2015 International Society for Neurochemistry.

Genetic variation in FADS genes is associated with maternal long-chain PUFA status but not with cognitive development of infants in a high fish-eating observational study.

PubMed

Yeates, Alison J; Love, Tanzy M; Engström, Karin; Mulhern, Maria S; McSorley, Emeir M; Grzesik, Katherine; Alhamdow, Ayman; Wahlberg, Karin; Thurston, Sally W; Davidson, Philip W; van Wijngaarden, Edwin; Watson, Gene E; Shamlaye, Conrad F; Myers, G J; Strain, J J; Broberg, Karin

2015-12-01

Long-chain n-6 and n-3 PUFA (LC-PUFA), arachidonic acid (AA) (20:4n-6) and DHA (22:6n-3), are critical for optimal brain development. These fatty acids can be consumed directly from the diet, or synthesized endogenously from precursor PUFA by Δ-5 (encoded by FADS1) and Δ-6 desaturases (encoded by FADS2). The aim of this study was to determine the potential importance of maternal genetic variability in FADS1 and FADS2 genes to maternal LC-PUFA status and infant neurodevelopment in populations with high fish intakes. The Nutrition Cohorts 1 (NC1) and 2 (NC2) are longitudinal observational mother-child cohorts in the Republic of Seychelles. Maternal serum LC-PUFA was measured at 28 weeks gestation and genotyping for rs174537 (FADS1), rs174561 (FADS1), rs3834458 (FADS1-FADS2) and rs174575 (FADS2) was performed in both cohorts. The children completed the Bayley Scales of Infant Development II (BSID-II) at 30 months in NC1 and at 20 months in NC2. Complete data were available for 221 and 1310 mothers from NC1 and NC2 respectively. With increasing number of rs3834458 minor alleles, maternal concentrations of AA were significantly decreased (NC1 p=0.004; NC2 p<0.001) and precursor:product ratios for linoleic acid (LA) (18:2n-6)-to-AA (NC1 p<0.001; NC2 p<0.001) and α-linolenic acid (ALA) (18:3n-3)-to-DHA were increased (NC2 p=0.028). There were no significant associations between maternal FADS genotype and BSID-II scores in either cohort. A trend for improved PDI was found among infants born to mothers with the minor rs3834458 allele.In these high fish-eating cohorts, genetic variability in FADS genes was associated with maternal AA status measured in serum and a subtle association of the FADS genotype was found with neurodevelopment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of dietary lipid on the growth, fatty acid composition and Δ5 Fads expression of abalone ( Haliotis discus hannai Ino) hepatopancreas

NASA Astrophysics Data System (ADS)

Li, Mingzhu; Mai, Kangsen; Ai, Qinghui; He, Gen; Xu, Wei; Zhang, Wenbing; Zhang, Yanjiao; Zhou, Huihui; Liufu, Zhiguo

2015-04-01

This study investigated the effect of dietary lipid on the growth, fatty acid composition and Δ5 fatty acyl desaturase genes ( Fads) expression of juvenile abalone ( Haliotis discus hannai Ino) hepatopancreas. Six purified diets were formulated to contain tripalmitin (TP), olive oil (OO, 72.87% 18:1n-9), grape seed oil (GO, 68.67% 18:2n-6), linseed oil (LO, 70.48% 18:3n-3), ARA oil (AO, 41.81% ARA) or EPA oil (EO, 44.09% EPA and 23.67% DAH). No significant difference in survival rate was observed among abalone fed with different diets. Weight gain rate ( WGR) and daily growth rate of shell length ( DGR SL) were significantly increased in abalone fed with diets containing OO, AO and EO, but decreased in abalone fed with LO diet ( P < 0.05) in comparison with those fed with TP. High level of dietary 18:2n-6 resulted in higher content of n-6 polyunsaturated fatty acids (PUFAs) in abalone fed with GO than those fed with TP, OO, LO and EO ( P < 0.05). n-3 PUFAs in abalone fed with LO was significantly higher than those in abalone fed with TP, OO, GO and AO ( P < 0.05). The highest contents of 20:1n-9 and 22:1n-9 were observed in abalone fed with OO. The expression of Δ5 Fads in hepatopancreas of abalone was enhanced by high concentration of 18:3n-3 and suppressed by dietary LC-PUFAs; however it was not affected by dietary high concentration of 18:1n-9 or 18:2n-6. These results provided valuable information for understanding the synthesis of LC-PUFAs and nutritional regulation of Δ5 Fads expression in abalone.

Functional identification and regulatory analysis of Δ6-fatty acid desaturase from the oleaginous fungus Mucor sp. EIM-10.

PubMed

Jiang, Xianzhang; Liu, Hongjiao; Niu, Yongchao; Qi, Feng; Zhang, Mingliang; Huang, Jianzhong

2017-03-01

To enlarge the diversity of the desaturases associated with PUFA biosynthesis and to better understand the transcriptional regulation of desaturases, a Δ 6 -desaturase gene (Md6) from Mucor sp. and its 5'-upstream sequence was functionally identified in Saccharomyces cerevisiae. Expression of the Δ 6 -fatty acid desaturase (Md6) in S. cerevisiae showed that Md6 could convert linolenic acid to γ-linolenic acid. Computational analysis of the promoter of Md6 suggested it contains several eukaryotic fundamental transcription regulatory elements. In vivo functional analysis of the promoter showed the 5'-upstream sequence of Md6 could initiate expression of GFP and Md6 itself in S. cerevisiae. A series deletion analysis of the promoter suggested that sequence between -919 to -784 bp (relative to start site) named as eMd6 is the key factor for high activity of Δ 6 -desaturase. The activity of Δ 6 -desaturase was increased by 2.8-fold and 2.5-fold when the eMd6 sequence was placed upstream of -434 with forward or reverse orientations respectively. To our best knowledge, the native promoter of Md6 from Mucor is the strongest promoter for Δ 6 -desaturase reported so far and the sequence between -919 to -784 bp is an enhancer for Δ 6 -desaturase activity.

Docosahexaenoic acid (DHA) supplementation in pregnancy differentially modulates arachidonic acid and DHA status across FADS genotypes in pregnancy.

PubMed

Scholtz, S A; Kerling, E H; Shaddy, D J; Li, S; Thodosoff, J M; Colombo, J; Carlson, S E

2015-03-01

Some FADS alleles are associated with lower DHA and ARA status assessed by the relative amount of arachidonic acid (ARA) and docosahexaenoic acid (DHA) in plasma and red blood cell (RBC) phospholipids (PL). We determined two FADS single nucleotide polymorphisms (SNPs) in a cohort of pregnant women and examined the relationship of FADS1rs174533 and FADS2rs174575 to DHA and ARA status before and after supplementation with 600mg per day of DHA. The 205 pregnant women studied were randomly assigned to placebo (mixed soy and corn oil) (n=96) or 600mg algal DHA (n=109) in 3 capsules per day for the last two trimesters of pregnancy. Women homozygous for the minor allele of FADS1rs174533 (but not FADS2rs174575) had lower DHA and ARA status at baseline. At delivery, minor allele homozygotes of FADS1rs174533 in the placebo group had lower RBC-DHA compared to major-allele carriers (P=0.031), while in the DHA-supplemented group, all genotypes had higher DHA status compared to baseline (P=0.001) and status did not differ by genotype (P=0.941). Surprisingly, DHA but not the placebo decreased ARA status of minor allele homozygotes of both FADS SNPs but not major allele homozygotes at delivery. Any physiological effects of changing the DHA to ARA ratio by increasing DHA intake appears to be greater in minor allele homozygotes of some FADS SNPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

A More Desirable Balanced Polyunsaturated Fatty Acid Composition Achieved by Heterologous Expression of Δ15/Δ4 Desaturases in Mammalian Cells

PubMed Central

Zhu, Guiming; Ou, Qin; Zhang, Tao; Jiang, Xudong; Sun, Guozhi; Zhang, Ning; Wang, Kunfu; Fang, Heng; Wang, Mingfu; Sun, Jie; Ge, Tangdong

2013-01-01

Arachidonic (ARA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids are the most biologically active polyunsaturated fatty acids, but their biosyntheses in mammals are very limited. The biosynthesis of DHA is the most difficult, because this undergoes the Sprecher pathway–a further elongation step from docosapentaenoic acid (DPA), a Δ6-desaturase acting on a C24 fatty acid substrate followed by a peroxisomal chain shortening step. This paper reports the successful heterologous expression of two non-mammalian genes (with modification of codon usage), coding for Euglena gracilis Δ4-desaturase and Siganus canaliculatus Δ4-desaturase respectively, in mammalian cells (HEK293 cell line). Both of the Δ4-desaturases can efficiently function, directly converting DPA into DHA. Moreover, the cooperation of the E. gracilis Δ4-desaturase with C. elegans Δ15-desaturase (able to convert a number of n-6 PUFAs to their corresponding n-3 PUFAs) in transgenic HEK293 cells made a more desirable fatty acid composition – a drastically reduced n-6/n-3 PUFAs ratio and a high level of DHA as well as EPA and ARA. Our findings provide a basis for potential applications of the gene constructs for expression of Δ15/Δ4-desaturases in transgenic livestock to produce such a fatty acid profile in the related products, which certainly will bring benefit to human health. PMID:24391980

Nonsense-mediated mRNA degradation of CtFAD2-1 and development of a perfect molecular marker for olol mutation in high oleic safflower (Carthamus tinctorius L.).

PubMed

Liu, Qing; Cao, Shijiang; Zhou, Xue-Rong; Wood, Craig; Green, Allan; Singh, Surinder

2013-09-01

There are two types of safflower oil, high oleic (HO) with 70-75 % oleic acid and high linoleic (HL) with about 70 % linoleic acid. The original HO trait in safflower, found in an introduction from India, is controlled by a partially recessive allele ol at a single locus (Knowles and Bill 1964). In the lipid biosynthesis pathway of developing safflower seeds, microsomal oleoyl phosphatidylcholine desaturase (FAD2) is largely responsible for the conversion of oleic acid to linoleic acid. In vitro microsomal assays indicated drastically reduced FAD2 enzyme activity in the HO genotype compared to conventional HL safflower. A previous study indicated that a single-nucleotide deletion was found in the coding region of CtFAD2-1 that causes premature termination of translation in the HO genotypes, and the expression of the mutant CtFAD2-1Δ was attenuated in the HO genotypes compared to conventional HL safflower (Guan et al. 2012). In this study, we hypothesise that down-regulation of CtFAD2-1 expression in the HO genotype may be explained by nonsense-mediated RNA decay (NMD). NMD phenomenon, indicated by gene-specific RNA degradation of defective CtFAD2-1Δ, was subsequently confirmed in Arabidopsis thaliana seed as well as in the transient expression system in Nicotiana benthamiana leaves. We have developed a perfect molecular marker corresponding to the olol mutation that can facilitate a rapid screening and early detection of genotypes carrying the olol mutation for use in marker-assisted selection for the management of the HO trait in safflower breeding programmes.

Cognitive function in adolescence: testing for interactions between breast-feeding and FADS2 polymorphisms.

PubMed

Martin, Nicolas W; Benyamin, Beben; Hansell, Narelle K; Montgomery, Grant W; Martin, Nicholas G; Wright, Margaret J; Bates, Timothy C

2011-01-01

Breast-fed C-allele carriers of the rs174575 single nucleotide polymorphism in the fatty acyl desaturase 2 (FADS2) gene have been reported to show a 6.4 to 7 IQ point advantage over formula-fed C-allele carriers, with no effect of breast-feeding in GG carriers. An Australian sample was examined to determine if an interaction between breast-feeding and the rs174575 single nucleotide polymorphism had any effect on IQ. This hypothesis was tested in more than 700 families of adolescent twins assessed for IQ and breast-feeding, birth weight, and FADS2 polymorphisms, and parental socioeconomic status and education, and maternal FADS2 status. No significant evidence for a moderating effect on IQ of rs174575 C-carrier status and breast-feeding was found, and there no effects of maternal FADS2 status on offspring IQ. In addition, no main effects of any FADS2 polymorphisms on IQ were found when the genotype was kept as two-homozygote and one-heterozygote categories and indeed no evidence for effects of breast-feeding on IQ scores after controlling for parental socioeconomic status and education. The investigation was extended to two additional FADS2 polymorphisms (rs1535 and rs174583), but again, although these polymorphisms code alleles affecting fatty acid metabolism, no main or interaction effects were found on IQ. These results support the view that apparent effects of breast-feeding on IQ reflect differential likelihood of breast-feeding as a function of parental education and did not support the predicted interaction effect of FADS2 and breast-feeding on IQ. Copyright © 2011 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Novel Genes Encoding Hexadecanoic Acid Δ6-Desaturase Activity in a Rhodococcus sp.

PubMed

Araki, Hiroyuki; Hagihara, Hiroshi; Takigawa, Hirofumi; Tsujino, Yukiharu; Ozaki, Katsuya

2016-11-01

cis-6-Hexadecenoic acid, a major component of human sebaceous lipids, is involved in the defense mechanism against Staphylococcus aureus infection in healthy skin and closely related to atopic dermatitis. Previously, Koike et al. (Biosci Biotechnol Biochem 64:1064-1066, 2000) reported that a mutant strain of Rhodococcus sp. produced cis-6-hexadecenoate derivatives from palmitate alkyl esters. From the mutant Rhodococcus strain, we identified and sequenced two open reading frames present in an amplified 5.7-kb region; these open reading frames encoded tandemly repeated Δ6-desaturase-like genes, Rdes1 and Rdes2. A phylogenetic tree indicated that Rdes1 and Rdes2 were different from previously known Δ6-desaturase genes, and that they formed a new cluster. Rdes1 and Rdes2 were each introduced into vectors and then expressed separately in Escherichia coli, and the fatty acid composition of the transformed cells was analyzed by gas chromatography and mass spectrometry. The amount of cis-6-hexadecenoic acid was significantly higher in Rdes1- or Rdes2-transformed E. coli cells (twofold and threefold, respectively) than in vector-only control cells. These results showed that cis-6-hexadecenoic acid was produced in E. coli cells by the rhodococcal Δ6-desaturase-like proteins.

Impact of Genetic and Epigenetic Variations Within the FADS Cluster on the Composition and Metabolism of Polyunsaturated Fatty Acids in Prostate Cancer.

PubMed

Cui, Tao; Hester, Austin G; Seeds, Michael C; Rahbar, Elaheh; Howard, Timothy D; Sergeant, Susan; Chilton, Floyd H

2016-09-01

In vitro and experimental animal studies have demonstrated that high levels of omega-6 (n-6) polyunsaturated fatty acids (PUFAs) and high ratios of n-6 to omega-3 (n-3) PUFAs are strongly associated with the development and progression of prostate cancer (PCA). However, epidemiological studies in humans have demonstrated inconsistent findings linking dietary PUFAs and PCA risk. We hypothesize that genetic and epigenetic variations within the fatty acid desaturase (FADS) gene cluster produce gene-diet interactions that may explain these disparate findings. This study tested the relationship of the genotype of a single nucleotide polymorphism, rs174537, and the methylation status of a CpG site, cg27386326, with PUFA composition, and markers of PUFA biosynthesis in PCA tissue. Sixty PCA specimens from patients undergoing radical prostatectomy were genotyped, pyrosequenced and quantitated for fatty acids (FAs). Long-chain (LC)-PUFAs, such as arachidonic acid (ARA), were abundant in these specimens, with ARA accounting for 15.8% of total FAs. In addition, there was a positive association of the G allele at rs174537 with concentrations of ARA and adrenic acid and ratios of products to precursors within the n-6 PUFA pathway such that specimens from homozygous G individuals exhibited increasingly higher values as compared to specimens from heterozygous individuals and homozygous T individuals. Finally, the methylation status of cg27386326 was inversely correlated with tissue concentrations of LC-PUFAs and markers of LC-PUFA biosynthesis. These data reveal that genetic and epigenetic variations within the FADS cluster are highly associated with LC-PUFA concentrations and LC-PUFA biosynthetic capacity in PCA tissue. They also raise the potential that gene-PUFA interactions play an important role in PCA risk and severity. Prostate 76:1182-1191, 2016. © 2016 The Authors. The Prostate published by Wiley Periodicals, Inc. © 2016 The Authors. The Prostate published by Wiley

Homology modeling and docking studies of a Δ9-fatty acid desaturase from a Cold-tolerant Pseudomonas sp. AMS8

PubMed Central

Garba, Lawal; Mohamad Yussoff, Mohamad Ariff; Abd Halim, Khairul Bariyyah; Ishak, Siti Nor Hasmah; Mohamad Ali, Mohd Shukuri; Oslan, Siti Nurbaya

2018-01-01

Membrane-bound fatty acid desaturases perform oxygenated desaturation reactions to insert double bonds within fatty acyl chains in regioselective and stereoselective manners. The Δ9-fatty acid desaturase strictly creates the first double bond between C9 and 10 positions of most saturated substrates. As the three-dimensional structures of the bacterial membrane fatty acid desaturases are not available, relevant information about the enzymes are derived from their amino acid sequences, site-directed mutagenesis and domain swapping in similar membrane-bound desaturases. The cold-tolerant Pseudomonas sp. AMS8 was found to produce high amount of monounsaturated fatty acids at low temperature. Subsequently, an active Δ9-fatty acid desaturase was isolated and functionally expressed in Escherichia coli. In this paper we report homology modeling and docking studies of a Δ9-fatty acid desaturase from a Cold-tolerant Pseudomonas sp. AMS8 for the first time to the best of our knowledge. Three dimensional structure of the enzyme was built using MODELLER version 9.18 using a suitable template. The protein model contained the three conserved-histidine residues typical for all membrane-bound desaturase catalytic activity. The structure was subjected to energy minimization and checked for correctness using Ramachandran plots and ERRAT, which showed a good quality model of 91.6 and 65.0%, respectively. The protein model was used to preform MD simulation and docking of palmitic acid using CHARMM36 force field in GROMACS Version 5 and Autodock tool Version 4.2, respectively. The docking simulation with the lowest binding energy, −6.8 kcal/mol had a number of residues in close contact with the docked palmitic acid namely, Ile26, Tyr95, Val179, Gly180, Pro64, Glu203, His34, His206, His71, Arg182, Thr85, Lys98 and His177. Interestingly, among the binding residues are His34, His71 and His206 from the first, second, and third conserved histidine motif, respectively, which constitute

Development of marker-free transgenic Jatropha plants with increased levels of seed oleic acid

PubMed Central

2012-01-01

Background Jatropha curcas is recognized as a new energy crop due to the presence of the high amount of oil in its seeds that can be converted into biodiesel. The quality and performance of the biodiesel depends on the chemical composition of the fatty acids present in the oil. The fatty acids profile of the oil has a direct impact on ignition quality, heat of combustion and oxidative stability. An ideal biodiesel composition should have more monounsaturated fatty acids and less polyunsaturated acids. Jatropha seed oil contains 30% to 50% polyunsaturated fatty acids (mainly linoleic acid) which negatively impacts the oxidative stability and causes high rate of nitrogen oxides emission. Results The enzyme 1-acyl-2-oleoyl-sn-glycero-3-phosphocholine delta 12-desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. We identified three putative delta 12 fatty acid desaturase genes in Jatropha (JcFAD2s) through genome-wide analysis and downregulated the expression of one of these genes, JcFAD2-1, in a seed-specific manner by RNA interference technology. The resulting JcFAD2-1 RNA interference transgenic plants showed a dramatic increase of oleic acid (> 78%) and a corresponding reduction in polyunsaturated fatty acids (< 3%) in its seed oil. The control Jatropha had around 37% oleic acid and 41% polyunsaturated fatty acids. This indicates that FAD2-1 is the major enzyme responsible for converting oleic acid to linoleic acid in Jatropha. Due to the changes in the fatty acids profile, the oil of the JcFAD2-1 RNA interference seed was estimated to yield a cetane number as high as 60.2, which is similar to the required cetane number for conventional premium diesel fuels (60) in Europe. The presence of high seed oleic acid did not have a negative impact on other Jatropha agronomic traits based on our preliminary data of the original plants under greenhouse conditions. Further, we developed a marker-free system to generate the transgenic

Serum Lipid Concentrations and FADS Genetic Variants in Young Mexican College Students: The UP-AMIGOS Cohort Study.

PubMed

Vazquez-Vidal, Itzel; Voruganti, V Saroja; Hannon, Bridget A; Andrade, Flavia Cristina Drumond; Aradillas-García, Celia; Nakamura, Manabu T; Terán-García, Margarita

2018-05-30

Recent genome-wide association studies in the Mexican population have identified several genetic loci associated with blood lipid levels in adults. However, studies focusing on the fatty acid desaturase (FADS) gene cluster have been understudied in this population, even though it seems associated with lipid profiles in other ethnicities. The aim of this study was to test associations between single nucleotide polymorphisms (SNPs) in the FADS cluster (rs174546, rs1535, rs174548, rs174550, rs174450, and rs174618) and serum lipid profiles in young Mexicans. Anthropometrics, serum lipid profiles, and FADS SNPs were measured in 998 subjects in the UP-AMIGOS cohort study. Genotype-phenotype (total cholesterol [TC], triglyceride [TG], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and very-low-density lipoprotein [VLDL]) associations were assessed using PLINK adjusted for sex, age, and body mass index (BMI). Among 6 FADS SNPs, we found that carriers of the C-allele of the FADS1-rs174546 showed a significant association with lower TG concentrations (β = -12.6 mg/dL, p = 0.009) and lower VLDL concentrations (β = -2.52 mg/dL, p = 0.005). We found that rs174546, rs1535, and rs174550 were in high linkage disequilibrium (r2 > 0.80). There were no significant associations between rs174550, rs174548, and rs174618 and lipid profiles. A genetic variant in the FADS1 (rs174546) gene is a major contributor of plasma TG and VLDL concentrations in healthy young Mexicans. © 2018 S. Karger AG, Basel.

Maternal single nucleotide polymorphisms in the fatty acid desaturase 1 and 2 coding regions modify the impact of prenatal supplementation with DHA on birth weight.

PubMed

Gonzalez-Casanova, Ines; Rzehak, Peter; Stein, Aryeh D; Garcia Feregrino, Raquel; Rivera Dommarco, Juan A; Barraza-Villarreal, Albino; Demmelmair, Hans; Romieu, Isabelle; Villalpando, Salvador; Martorell, Reynaldo; Koletzko, Berthold; Ramakrishnan, Usha

2016-04-01

Specific single nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) gene affect the activity and efficiency of enzymes that are responsible for the conversion of polyunsaturated fatty acids (PUFAs) into their long-chain active form. A high prevalence of SNPs that are associated with slow PUFA conversion has been described in Hispanic populations. We assessed the heterogeneity of the effect of prenatal supplementation with docosahexaenoic acid (DHA) on birth weight across selected FADS SNPs in a sample of Mexican women and their offspring. We obtained information on the maternal genotype from stored blood samples of 654 women who received supplementation with 400 mg DHA/d or a placebo from weeks 18 to 22 of gestation through delivery as part of a randomized controlled trial conducted in Cuernavaca, Mexico. We selected 4 tag SNPs (rs174455, rs174556, rs174602, and rs498793) in the FADS region for analysis. We used an ANOVA to test for the heterogeneity of the effect on birth weight across each of the 4 SNPs. The mean ± SD birth weight was 3210 ± 470 g, and the weight-for-age z score (WAZ) was -0.24 ± 1.00. There were no intention-to-treat differences in birth weights. We showed significant heterogeneity by SNP rs174602 (P= 0.02); offspring of carriers of alleles TT and TC in the intervention group were heavier than those in the placebo group (WAZ: -0.13 ± 0.14 and -0.20 ± 0.08 compared with -0.55 ± 0.15 and -0.39 ± 0.09, respectively); there were no significant differences in offspring of rs174602 CC homozygotes (WAZ: -0.26 ± 0.09 in the intervention group compared with -0.04 ± 0.09 in the placebo group). We showed no significant heterogeneity across the other 3 FADS SNPs. Differential responses to prenatal DHA supplementation on the basis of the genetic makeup of target populations could explain the mixed evidence of the impact of DHA supplementation on birth weight. This trial was registered at clinicaltrials.gov as NCT00646360. © 2016

Variants of the FADS1 FADS2 Gene Cluster, Blood Levels of Polyunsaturated Fatty Acids and Eczema in Children within the First 2 Years of Life

PubMed Central

Rzehak, Peter; Thijs, Carel; Standl, Marie; Mommers, Monique; Glaser, Claudia; Jansen, Eugène; Klopp, Norman; Koppelman, Gerard H.; Singmann, Paula; Postma, Dirkje S.; Sausenthaler, Stefanie; Dagnelie, Pieter C.; van den Brandt, Piet A.; Koletzko, Berthold; Heinrich, Joachim

2010-01-01

Background Association of genetic-variants in the FADS1-FADS2-gene-cluster with fatty-acid-composition in blood of adult-populations is well established. We analyze this genetic-association in two children-cohort-studies. In addition, the association between variants in the FADS-gene-cluster and blood-fatty-acid-composition with eczema was studied. Methods and Principal Findings Data of two population-based-birth-cohorts in the Netherlands and Germany (KOALA, LISA) were pooled (n = 879) and analyzed by (logistic) regression regarding the mutual influence of single-nucleotide-polymorphisms (SNPs) in the FADS-gene-cluster (rs174545, rs174546, rs174556, rs174561, rs3834458), on polyunsaturated fatty acids (PUFA) in blood and parent-reported eczema until the age of 2 years. All SNPs were highly significantly associated with all PUFAs except for alpha-linolenic-acid and eicosapentaenoic-acid, also after correction for multiple-testing. All tested SNPs showed associations with eczema in the LISA-study, but not in the KOALA-study. None of the PUFAs was significantly associated with eczema neither in the pooled nor in the analyses stratified by study-cohort. Conclusions and Significance PUFA-composition in young children's blood is under strong control of the FADS-gene-cluster. Inconsistent results were found for a link between these genetic-variants with eczema. PUFA in blood was not associated with eczema. Thus the hypothesis of an inflammatory-link between PUFA and eczema by the metabolic-pathway of LC-PUFAs as precursors for inflammatory prostaglandins and leukotrienes could not be confirmed by these data. PMID:20948998

Maternal single nucleotide polymorphisms in the fatty acid desaturase 1 and 2 coding regions modify the impact of prenatal supplementation with DHA on birth weight12

PubMed Central

Gonzalez-Casanova, Ines; Rzehak, Peter; Stein, Aryeh D; Garcia Feregrino, Raquel; Dommarco, Juan A Rivera; Barraza-Villarreal, Albino; Demmelmair, Hans; Romieu, Isabelle; Villalpando, Salvador; Martorell, Reynaldo; Koletzko, Berthold; Ramakrishnan, Usha

2016-01-01

Background: Specific single nucleotide polymorphisms (SNPs) in the fatty acid desaturase (FADS) gene affect the activity and efficiency of enzymes that are responsible for the conversion of polyunsaturated fatty acids (PUFAs) into their long-chain active form. A high prevalence of SNPs that are associated with slow PUFA conversion has been described in Hispanic populations. Objective: We assessed the heterogeneity of the effect of prenatal supplementation with docosahexaenoic acid (DHA) on birth weight across selected FADS SNPs in a sample of Mexican women and their offspring. Design: We obtained information on the maternal genotype from stored blood samples of 654 women who received supplementation with 400 mg DHA/d or a placebo from weeks 18 to 22 of gestation through delivery as part of a randomized controlled trial conducted in Cuernavaca, Mexico. We selected 4 tag SNPs (rs174455, rs174556, rs174602, and rs498793) in the FADS region for analysis. We used an ANOVA to test for the heterogeneity of the effect on birth weight across each of the 4 SNPs. Results: The mean ± SD birth weight was 3210 ± 470 g, and the weight-for-age z score (WAZ) was −0.24 ± 1.00. There were no intention-to-treat differences in birth weights. We showed significant heterogeneity by SNP rs174602 (P = 0.02); offspring of carriers of alleles TT and TC in the intervention group were heavier than those in the placebo group (WAZ: −0.13 ± 0.14 and −0.20 ± 0.08 compared with −0.55 ± 0.15 and −0.39 ± 0.09, respectively); there were no significant differences in offspring of rs174602 CC homozygotes (WAZ: −0.26 ± 0.09 in the intervention group compared with −0.04 ± 0.09 in the placebo group). We showed no significant heterogeneity across the other 3 FADS SNPs. Conclusion: Differential responses to prenatal DHA supplementation on the basis of the genetic makeup of target populations could explain the mixed evidence of the impact of DHA supplementation on birth weight. This

Depressed expression of FAE1 and FAD2 genes modifies fatty acid profiles and storage compounds accumulation in Brassica napus seeds.

PubMed

Shi, Jianghua; Lang, Chunxiu; Wang, Fulin; Wu, Xuelong; Liu, Renhu; Zheng, Tao; Zhang, Dongqing; Chen, Jinqing; Wu, Guanting

2017-10-01

In plants, the enzymes fatty acid dehydrogenase 2 (FAD2) and fatty acid elongase 1 (FAE1) have been shown in previous studies to play important roles in the de novo biosynthesis of fatty acids. However, the effects of depressed expression of FAD2 and FAE1 on seed storage compounds accumulation remains to be elucidated. In this study, we produced RNA interfering transgenic rapeseeds lines, BnFAD2-Ri, BnFAE1-Ri and BnFAD2/BnFAE1-Ri, which exhibited depressed expression of the BnFAD2 and BnFAE1 genes under the control of seed-specific napin A promoter. These transgenic rapeseeds showed normal growth and development as compared with the wild type (CY2). Depressed expression of BnFAD2 and BnFAE1 genes modified fatty acid profiles, leading to increased oleic acid and decreased erucic acid contents in transgenic seeds. Consistent with these results, the ratios of C18:1/C18:2 and C18:1/C18:3 in C18 unsaturated fatty acids were greatly increased due to increased oleic acid content in transgenic seeds. Moreover, depressed expression of BnFAD2 and BnFAE1 genes resulted in slightly decreased oil contents and increased protein contents in transgenic seeds. Our results demonstrated that depressed expression of BnFAD2 and BnFAE1 greatly improves seed nutritional quality by modulating the fatty acid metabolism and storage products accumulation and that BnFAD2 and BnFAE1 are reliable targets for genetic improvement of rapeseed in seed nutritional quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Cognitive Function in Adolescence: Testing for Interactions Between Breast-Feeding and "FADS2" Polymorphisms

ERIC Educational Resources Information Center

Martin, Nicolas W.; Benyamin, Beben; Hansell, Narelle K.; Montgomery, Grant W.; Martin, Nicholas G.; Wright, Margaret J.; Bates, Timothy C.

2011-01-01

Objectives: Breast-fed C-allele carriers of the rs single nucleotide polymorphism in the fatty acyl desaturase 2 ("FADS2") gene have been reported to show a 6.4 to 7 IQ point advantage over formula-fed C-allele carriers, with no effect of breast-feeding in GG carriers. An Australian sample was examined to determine if an interaction between…

Effects of Addition of Linseed and Marine Algae to the Diet on Adipose Tissue Development, Fatty Acid Profile, Lipogenic Gene Expression, and Meat Quality in Lambs

PubMed Central

Urrutia, Olaia; Mendizabal, José Antonio; Insausti, Kizkitza; Soret, Beatriz; Purroy, Antonio; Arana, Ana

2016-01-01

This study examined the effect of linseed and algae on growth and carcass parameters, adipocyte cellularity, fatty acid profile and meat quality and gene expression in subcutaneous and intramuscular adipose tissues (AT) in lambs. After weaning, 33 lambs were fed three diets up to 26.7 ± 0.3 kg: Control diet (barley and soybean); L diet (barley, soybean and 10% linseed) and L-A diet (barley, soybean, 5% linseed and 3.89% algae). Lambs fed L-A diet showed lower average daily gain and greater slaughter age compared to Control and L (P < 0.001). Carcass traits were not affected by L and L-A diets, but a trend towards greater adipocyte diameter was observed in L and L-A in the subcutaneous AT (P = 0.057). Adding either linseed or linseed and algae increased α-linolenic acid and eicosapentaenoic acid contents in both AT (P < 0.001); however, docosahexaenoic acid was increased by L-A (P < 0.001). The n-6/n-3 ratio decreased in L and L-A (P < 0.001). Algae had adverse effects on meat quality, with greater lipid oxidation and reduced ratings for odor and flavor. The expression of lipogenic genes was downregulated in the subcutaneous AT (P < 0.05): acetyl-CoA carboxylase 1 (ACACA) in L and L-A and lipoprotein lipase (LPL) and stearoyl-CoA desaturase (SCD) in L-A. Fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and fatty acid elongase 5 (ELOVL5) were unaffected. In the subcutaneous AT, supplementing either L or L-A increased peroxisome proliferator-activated receptor gamma (PPARG) and CAAT-enhancer binding protein alpha (CEBPA) (P < 0.05), although it had no effect on sterol regulatory element-binding factor 1 (SREBF1). In the intramuscular AT, expression of ACACA, SCD, FADS1 and FADS2 decreased in L and L-A (P < 0.001) and LPL in L (P < 0.01), but PPARG, CEBPA and SREBF1 were unaffected. PMID:27253325

Conjugated Fatty Acid Synthesis

PubMed Central

Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

2012-01-01

Conjugated linolenic acids (CLNs), 18:3 Δ9,11,13, lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ9,12,15). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ9cis,11trans,13cis) or α-eleostearic acid (18:3 Δ9cis,11trans,13trans). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation. PMID:22451660

Either fadD1 or fadD2, Which Encode acyl-CoA Synthetase, Is Essential for the Survival of Haemophilus parasuis SC096.

PubMed

Feng, Saixiang; Xu, Chenggang; Yang, Kaijie; Wang, Haihong; Fan, Huiying; Liao, Ming

2017-01-01

In Haemophilus parasuis , the genes HAPS_0217 and HAPS_1695 are predicted to encode long-chain fatty acid-CoA ligases (FACSs). These proteins contain ATP/AMP signature motifs and FACS conserved motifs that are homologous to those in Escherichia coli FadD (EcFadD). In this study, we demonstrate that HAPS_0217 and HAPS_1695 can functionally replace EcFadD in the E. coli fadD mutant JW1794, and were thus designated fadD1 and fadD2 , respectively. An evaluation of kinetic parameters indicated that FadD1 and FadD2 have a substrate preference for long-chain fatty acids. Moreover, FadD2 exhibited substrate inhibition in the presence of high concentrations of oleic acid. Single mutants of each of the fadD genes were easily constructed, whereas double mutants were not. These results were further confirmed using genomic site-directed mutagenesis, which supported the idea that H. parasuis requires either fadD1 or fadD2 for survival. The fadD1 mutant exhibited slower growth than the wild-type strain SC096, and its complementation resulted in a restored phenotype. The wild-type strain did not grow on chemically defined medium without the addition of oleic acid, indicating that lipids are a vital nutrient for this bacterium. Additionally, strains with a disrupted fadD1 gene also exhibited increased sensitivity to quinolone antibiotics, including levofloxacin, enrofloxacin, ciprofloxacin and nalidixic acid.

Altered fatty acid metabolism and reduced stearoyl-coenzyme a desaturase activity in asthma.

PubMed

Rodriguez-Perez, N; Schiavi, E; Frei, R; Ferstl, R; Wawrzyniak, P; Smolinska, S; Sokolowska, M; Sievi, N A; Kohler, M; Schmid-Grendelmeier, P; Michalovich, D; Simpson, K D; Hessel, E M; Jutel, M; Martin-Fontecha, M; Palomares, O; Akdis, C A; O'Mahony, L

2017-11-01

Fatty acids and lipid mediator signaling play an important role in the pathogenesis of asthma, yet this area remains largely underexplored. The aims of this study were (i) to examine fatty acid levels and their metabolism in obese and nonobese asthma patients and (ii) to determine the functional effects of altered fatty acid metabolism in experimental models. Medium- and long-chain fatty acid levels were quantified in serum from 161 human volunteers by LC/MS. Changes in stearoyl-coenzyme A desaturase (SCD) expression and activity were evaluated in the ovalbumin (OVA) and house dust mite (HDM) murine models. Primary human bronchial epithelial cells from asthma patients and controls were evaluated for SCD expression and activity. The serum desaturation index (an indirect measure of SCD) was significantly reduced in nonobese asthma patients and in the OVA murine model. SCD1 gene expression was significantly reduced within the lungs following OVA or HDM challenge. Inhibition of SCD in mice promoted airway hyper-responsiveness. SCD1 expression was suppressed in bronchial epithelial cells from asthma patients. IL-4 and IL-13 reduced epithelial cell SCD1 expression. Inhibition of SCD reduced surfactant protein C expression and suppressed rhinovirus-induced IP-10 secretion, which was associated with increased viral titers. This is the first study to demonstrate decreased fatty acid desaturase activity in humans with asthma. Experimental models in mice and human epithelial cells suggest that inhibition of desaturase activity leads to airway hyper-responsiveness and reduced antiviral defense. SCD may represent a new target for therapeutic intervention in asthma patients. © 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.

delta 6 Hexadecenoic acid is synthesized by the activity of a soluble delta 6 palmitoyl-acyl carrier protein desaturase in Thunbergia alata endosperm.

PubMed

Cahoon, E B; Cranmer, A M; Shanklin, J; Ohlrogge, J B

1994-11-04

delta 6 Hexadecenoic acid (16:1 delta 6) composes more than 80% of the seed oil of Thunbergia alata. Studies were conducted to determine the biosynthetic origin of the double bond of this unusual fatty acid. Assays of fractions of developing T. alata seed endosperm with [1-14C]palmitoyl (16:0)-acyl carrier protein (ACP) revealed the presence of a soluble delta 6 desaturase activity. This activity was greatest when 16:0-ACP was provided as a substrate, whereas no desaturation of the coenzyme A ester of this fatty acid was detected. In addition, delta 6 16:0-ACP desaturase activity in T. alata endosperm extracts was dependent on the presence of ferredoxin and molecular oxygen and was stimulated by catalase. To further characterize this enzyme, a cDNA encoding a diverged acyl-ACP desaturase was isolated from a T. alata endosperm cDNA library using polymerase chain reaction with degenerate oligonucleotides corresponding to conserved amino acid sequences in delta 9 stearoyl (18:0)- and delta 4 16:0-ACP desaturases. The primary structure of the mature peptide encoded by this cDNA shares 66% identity with the mature castor delta 9 18:0-ACP desaturase and 57% identity with the mature coriander delta 4 16:0-ACP desaturase. Extracts of Escherichia coli that express the T. alata cDNA catalyzed the delta 6 desaturation of 16:0-ACP. These results demonstrate that 16:1 delta 6 in T. alata endosperm is formed by the activity of a soluble delta 6 16:0-ACP desaturase that is structurally related to the delta 9 18:0- and delta 4 16:0-ACP desaturases. Implications of this work to an understanding of active site structures of acyl-ACP desaturases are discussed.

Direct stacking of sequence-specific nuclease-induced mutations to produce high oleic and low linolenic soybean oil.

PubMed

Demorest, Zachary L; Coffman, Andrew; Baltes, Nicholas J; Stoddard, Thomas J; Clasen, Benjamin M; Luo, Song; Retterath, Adam; Yabandith, Ann; Gamo, Maria Elena; Bissen, Jeff; Mathis, Luc; Voytas, Daniel F; Zhang, Feng

2016-10-13

The ability to modulate levels of individual fatty acids within soybean oil has potential to increase shelf-life and frying stability and to improve nutritional characteristics. Commodity soybean oil contains high levels of polyunsaturated linoleic and linolenic acid, which contribute to oxidative instability - a problem that has been addressed through partial hydrogenation. However, partial hydrogenation increases levels of trans-fatty acids, which have been associated with cardiovascular disease. Previously, we generated soybean lines with knockout mutations within fatty acid desaturase 2-1A (FAD2-1A) and FAD2-1B genes, resulting in oil with increased levels of monounsaturated oleic acid (18:1) and decreased levels of linoleic (18:2) and linolenic acid (18:3). Here, we stack mutations within FAD2-1A and FAD2-1B with mutations in fatty acid desaturase 3A (FAD3A) to further decrease levels of linolenic acid. Mutations were introduced into FAD3A by directly delivering TALENs into fad2-1a fad2-1b soybean plants. Oil from fad2-1a fad2-1b fad3a plants had significantly lower levels of linolenic acid (2.5 %), as compared to fad2-1a fad2-1b plants (4.7 %). Furthermore, oil had significantly lower levels of linoleic acid (2.7 % compared to 5.1 %) and significantly higher levels of oleic acid (82.2 % compared to 77.5 %). Transgene-free fad2-1a fad2-1b fad3a soybean lines were identified. The methods presented here provide an efficient means for using sequence-specific nucleases to stack quality traits in soybean. The resulting product comprised oleic acid levels above 80 % and linoleic and linolenic acid levels below 3 %.

Pomegranate seed oil influences the fatty acids profile and reduces the activity of desaturases in livers of Sprague-Dawley rats.

PubMed

Białek, Agnieszka; Stawarska, Agnieszka; Bodecka, Joanna; Białek, Małgorzata; Tokarz, Andrzej

2017-07-01

The aim of our study was to compare the influence of diet supplementation with pomegranate seed oil - as conjugated linolenic acids (CLnA) source, or conjugated linoleic acids (CLA) and to examine the mechanism of their activity. The content of fatty acids, levels of biomarkers of lipids' oxidation and the activity of key enzymes catalyzing lipids metabolism were measured. Obtained results revealed that conjugated fatty acids significantly decrease the activity of Δ5-desaturase (p=0.0001) and Δ6-desaturase (p=0.0008) and pomegranate seed oil reduces their activity in the most potent way. We confirmed that diet supplementation with pomegranate seed oil - a rich source of punicic acid leads to the increase of cis-9, trans-11 CLA content in livers (p=0.0003). Lack of side effects and beneficial influence on desaturases activity and fatty acids profile claim pomegranate seed oil to become interesting alternative for CLA as functional food. Copyright © 2017 Elsevier Inc. All rights reserved.

Temperature and metal exposure affect membrane fatty acid composition and transcription of desaturases and elongases in fathead minnow muscle and brain.

PubMed

Fadhlaoui, Mariem; Pierron, Fabien; Couture, Patrice

2018-02-01

In this study, we tested the hypothesis that metal exposure affected the normal thermal response of cell membrane FA composition and of elongase and desaturase gene transcription levels. To this end, muscle and brain membrane FA composition and FA desaturase (fads2, degs2 and scd2) and elongase (elovl2, elovl5 and elovl6) gene transcription levels were analyzed in fathead minnows (Pimephales promelas) acclimated for eight weeks to 15, 25 or 30°C exposed or not to cadmium (Cd, 6μg/l) or nickel (Ni, 450 6μg/l). The response of membrane FA composition to temperature variations or metal exposure differed between muscle and brain. In muscle, an increase of temperature induced a decrease of polyunsaturated FA (PUFA) and an increase of saturated FA (SFA) in agreement with the current paradigm. Although a similar response was observed in brain between 15 and 25°C, at 30°C, brain membrane unsaturation was higher than predicted. In both tissues, metal exposure affected the normal thermal response of membrane FA composition. The transcription of desaturases and elongases was higher in the brain and varied with acclimation temperature and metal exposure but these variations did not generally reflect changes in membrane FA composition. The mismatch between gene transcription and membrane composition highlights that several levels of control other than gene transcription are involved in adjusting membrane FA composition, including post-transcriptional regulation of elongases and desaturases and de novo phospholipid biosynthesis. Our study also reveals that metal exposure affects the mechanisms involved in adjusting cell membrane FA composition in ectotherms. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed Central

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

2016-01-01

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

Production of polyunsaturated fatty acids in yeast Saccharomyces cerevisiae and its relation to alkaline pH tolerance.

PubMed

Yazawa, Hisashi; Iwahashi, Hitoshi; Kamisaka, Yasushi; Kimura, Kazuyoshi; Uemura, Hiroshi

2009-03-01

Saccharomyces cerevisiae produces saturated and monounsaturated fatty acids of 16- and 18-carbon atoms and no polyunsaturated fatty acids (PUFAs) with more than two double bonds. To study the biological significance of PUFAs in yeast, we introduced Kluyveromyces lactis Delta12 fatty acid desaturase (KlFAD2) and omega3 fatty acid desaturase (KlFAD3) genes into S. cerevisiae to produce linoleic and alpha-linolenic acids in S. cerevisiae. The strain producing linoleic and alpha-linolenic acids showed an alkaline pH-tolerant phenotype. DNA microarray analyses showed that the transcription of a set of genes whose expressions are under the repression of Rim101p were downregulated in this strain, suggesting that Rim101p, a transcriptional repressor which governs the ion tolerance, was activated. In line with this activation, the strain also showed elevated resistance to Li(+) and Na(+) ions and to zymolyase, a yeast lytic enzyme preparation containing mainly beta-1,3-glucanase, indicating that the cell wall integrity was also strengthened in this strain. Our findings demonstrate a novel influence of PUFA production on transcriptional control that is likely to play an important role in the early stage of alkaline stress response. The Accession No. for microarray data in the Center for Information Biology Gene Expression database is CBX68.

Serum Fatty Acids, Desaturase Activities and Abdominal Obesity – A Population-Based Study of 60-Year Old Men and Women

PubMed Central

Alsharari, Zayed D.; Risérus, Ulf; Leander, Karin; Sjögren, Per; Carlsson, Axel C.; Vikström, Max; Laguzzi, Federica; Gigante, Bruna; Cederholm, Tommy; De Faire, Ulf; Hellénius, Mai-Lis

2017-01-01

Abdominal obesity is a key contributor of metabolic disease. Recent trials suggest that dietary fat quality affects abdominal fat content, where palmitic acid and linoleic acid influence abdominal obesity differently, while effects of n-3 polyunsaturated fatty acids are less studied. Also, fatty acid desaturation may be altered in abdominal obesity. We aimed to investigate cross-sectional associations of serum fatty acids and desaturases with abdominal obesity prevalence in a population-based cohort study. Serum cholesteryl ester fatty acids composition was measured by gas chromatography in 60-year old men (n = 1883) and women (n = 2015). Cross-sectional associations of fatty acids with abdominal obesity prevalence and anthropometric measures (e.g., sagittal abdominal diameter) were evaluated in multivariable-adjusted logistic and linear regression models, respectively. Similar models were employed to investigate relations between desaturase activities (estimated by fatty acid ratios) and abdominal obesity. In logistic regression analyses, palmitic acid, stearoyl-CoA-desaturase and Δ6-desaturase indices were associated with abdominal obesity; multivariable-adjusted odds ratios (95% confidence intervals) for highest versus lowest quartiles were 1.45 (1.19–1.76), 4.06 (3.27–5.05), and 3.07 (2.51–3.75), respectively. Linoleic acid, α-linolenic acid, docohexaenoic acid, and Δ5-desaturase were inversely associated with abdominal obesity; multivariable-adjusted odds ratios (95% confidence intervals): 0.39 (0.32–0.48), 0.74 (0.61–0.89), 0.76 (0.62–0.93), and 0.40 (0.33–0.49), respectively. Eicosapentaenoic acid was not associated with abdominal obesity. Similar results were obtained from linear regression models evaluating associations with different anthropometric measures. Sex-specific and linear associations were mainly observed for n3-polyunsaturated fatty acids, while associations of the other exposures were generally non-linear and similar across

Novel polymorphism in FADS1 gene and fish consumption on risk of oral cancer: A case-control study in southeast China.

PubMed

Chen, Fa; Lin, Tao; Yan, Lingjun; Liu, Fengqiong; Huang, Jiangfeng; Liu, Fangping; Wu, Junfeng; Qiu, Yu; Lin, Lisong; Cai, Lin; He, Baochang

2017-02-28

The aim of this study was to investigate the independent and combined effects of fatty acid desaturase 1 (FADS1) gene polymorphism and fish consumption on oral cancer. A hospital-based case-control study was performed including 305 oral cancer patients and 579 cancer-free controls. The genotypes were determined by TaqMan genotyping assay. Non-conditional logistic regression model was used to assess the effects of FADS1 rs174549 polymorphism and fish intake. Subjects carrying A allele of rs174549 significantly reduced the risk of oral cancer (AA VS GG, OR: 0.65, 95% CI: 0.42-0.99; AA VS AG+GG, OR: 0.67, 95% CI: 0.46-0.98). Moreover, the statistically significant reverse associations were especially evident in men, smokers, alcohol drinkers and those age ≤ 60 years. Additionally, fish intake ≥7 times/week showed a 73% reduction in risk for oral cancer compared to those who ate fish less than 2 times/week (OR: 0.27, 95% CI: 0.18-0.42). Furthermore, a significant gene-diet multiplicative interaction was observed between FADS1 rs174549 polymorphism and fish intake for oral cancer (P=0.028). This preliminary study suggests that FADS1 rs174549 polymorphism and fish consumption may be protective factors for oral cancer, with a gene-diet multiplicative interaction. Functional studies with larger samples are required to confirm our findings.

Ser/Thr Phosphorylation Regulates the Fatty Acyl-AMP Ligase Activity of FadD32, an Essential Enzyme in Mycolic Acid Biosynthesis*

PubMed Central

Le, Nguyen-Hung; Molle, Virginie; Eynard, Nathalie; Miras, Mathieu; Stella, Alexandre; Bardou, Fabienne; Galandrin, Ségolène; Guillet, Valérie; André-Leroux, Gwenaëlle; Bellinzoni, Marco; Alzari, Pedro; Mourey, Lionel; Burlet-Schiltz, Odile; Daffé, Mamadou; Marrakchi, Hedia

2016-01-01

Mycolic acids are essential components of the mycobacterial cell envelope, and their biosynthetic pathway is a well known source of antituberculous drug targets. Among the promising new targets in the pathway, FadD32 is an essential enzyme required for the activation of the long meromycolic chain of mycolic acids and is essential for mycobacterial growth. Following the in-depth biochemical, biophysical, and structural characterization of FadD32, we investigated its putative regulation via post-translational modifications. Comparison of the fatty acyl-AMP ligase activity between phosphorylated and dephosphorylated FadD32 isoforms showed that the native protein is phosphorylated by serine/threonine protein kinases and that this phosphorylation induced a significant loss of activity. Mass spectrometry analysis of the native protein confirmed the post-translational modifications and identified Thr-552 as the phosphosite. Phosphoablative and phosphomimetic FadD32 mutant proteins confirmed both the position and the importance of the modification and its correlation with the negative regulation of FadD32 activity. Investigation of the mycolic acid condensation reaction catalyzed by Pks13, involving FadD32 as a partner, showed that FadD32 phosphorylation also impacts the condensation activity. Altogether, our results bring to light FadD32 phosphorylation by serine/threonine protein kinases and its correlation with the enzyme-negative regulation, thus shedding a new horizon on the mycolic acid biosynthesis modulation and possible inhibition strategies for this promising drug target. PMID:27590338

A multifunctional desaturase involved in the biosynthesis of the processionary moth sex pheromone

PubMed Central

Serra, Montserrat; Piña, Benjamin; Abad, José Luis; Camps, Francisco; Fabriàs, Gemma

2007-01-01

The sex pheromone of the female processionary moth, Thaumetopoea pityocampa, is a unique C16 enyne acetate that is biosynthesized from palmitic acid. Three consecutive desaturation reactions transform this saturated precursor into the triunsaturated fatty acyl intermediate: formation of (Z)-11-hexadecenoic acid, acetylenation to 11-hexadecynoic acid, and final Δ13 desaturation to (Z)-13-hexadecen-11-ynoic acid. By using degenerate primers common to all reported insect desaturases, a single cDNA sequence was isolated from total RNA of T. pityocampa female pheromone glands. The full-length transcript of this putative desaturase was expressed in elo1Δ/ole1Δ yeast mutants (both elongase 1 and Δ9 desaturase-deficient) for functional assays. The construct fully rescued the Δole1 yeast phenotype, confirming its desaturase activity. Analysis of the unsaturated products from transformed yeast extracts demonstrated that the cloned enzyme showed Δ11 desaturase, Δ11 acetylenase, and Δ13 desaturase activities. Therefore, this single desaturase may account for the three desaturation steps involved in the sex pheromone biosynthetic pathway of the processionary moth. PMID:17921252

Palmitic acid (16:0) competes with omega-6 linoleic and omega-3 ɑ-linolenic acids for FADS2 mediated Δ6-desaturation.

PubMed

Park, Hui Gyu; Kothapalli, Kumar S D; Park, Woo Jung; DeAllie, Christian; Liu, Lei; Liang, Allison; Lawrence, Peter; Brenna, J Thomas

2016-02-01

Sapienic acid, 16:1n-10 is the most abundant unsaturated fatty acid on human skin where its synthesis is mediated by FADS2 in the sebaceous glands. The FADS2 product introduces a double bond at the Δ6, Δ4 and Δ8 positions by acting on at least ten substrates, including 16:0, 18:2n-6, and 18:3n-3. Our aim was to characterize the competition for accessing FADS2 mediated Δ6 desaturation between 16:0 and the most abundant polyunsaturated fatty acids (PUFA) in the human diet, 18:2n-6 and 18:3n-3, to evaluate whether competition may be relevant in other tissues and thus linked to metabolic abnormalities associated with FADS2 or fatty acid levels. MCF7 cells stably transformed with FADS2 biosynthesize 16:1n-10 from exogenous 16:0 in preference to 16:1n-7, the immediate product of SCD highly expressed in cancer cell lines, and 16:1n-9 via partial β-oxidation of 18:1n-9. Increasing availability of 18:2n-6 or 18:3n-3 resulted in decreased bioconversion of 16:0 to 16:1n-10, simultaneously increasing the levels of highly unsaturated products. FADS2 cells accumulate the desaturation-elongation products 20:3n-6 and 20:4n-3 in preference to the immediate desaturation products 18:3n-6 and 18:4n-3 implying prompt/coupled elongation of the nascent desaturation products. MCF7 cells incorporate newly synthesized 16:1n-10 into phospholipids. These data suggest that excess 16:0 due to, for instance, de novo lipogenesis from high carbohydrate or alcohol consumption, inhibits synthesis of highly unsaturated fatty acids, and may in part explain why supplemental preformed EPA and DHA in some studies improves insulin resistance and other factors related to diabetes and metabolic syndrome aggravated by excess calorie consumption. Copyright © 2015 Elsevier B.V. All rights reserved.

Contribution of two ζ-carotene desaturases to the poly-cis desaturation pathway in the cyanobacterium Nostoc PCC 7120.

PubMed

Breitenbach, Jürgen; Bruns, Marius; Sandmann, Gerhard

2013-07-01

The presence of two completely unrelated ζ-carotene desaturases CrtQa and CrtQb in some Nostoc strains is unique. CrtQb is the ζ-carotene desaturase, which was acquired by almost all cyanobacteria. The additional CrtQa can be regarded as an evolutionary relict of the CrtI desaturase present in non-photosynthetic bacteria. By reconstruction of the carotene desaturation pathway, we showed that both enzymes from Nostoc PCC 7120 were active. However, they differed in their preferred utilization of ζ-carotene Z isomers. CrtQa converted ζ-carotene isomers that were poorly metabolized by CrtQb. In this respect, CrtQa complemented the reactions of CrtQb, which is an advantage avoiding dead ends in the poly-cis desaturation pathway. In addition to ζ-carotene desaturation, CrtQa still possesses the Z to E isomerase function of the ancestral desaturase CrtI. Biochemical characterization showed that CrtQb is an enzyme with one molecule of tightly bound FAD and acts as a dehydrogenase transferring hydrogen to oxidized plastoquinone.

FADS1 rs174549 Polymorphism May Predict a Favorable Response to Chemoradiotherapy in Oral Cancer Patients.

PubMed

Chen, Fa; He, Baochang; Yan, Lingjun; Qiu, Yu; Lin, Lisong; Cai, Lin

2017-01-01

The fatty acid desaturase 1 (FADS1) gene variant is a novel susceptibility marker for laryngeal squamous cell carcinoma identified by a recent genome-wide association study, but it is still unclear whether this genetic variant continues to influence oral cancer recurrence or death. The purpose of this study was to evaluate the role of FADS1 rs174549 polymorphism and its interaction with postoperative chemoradiotherapy in the prognosis of oral cancer. A prospective cohort study involving 304 oral cancer patients with surgical resection was conducted in Fujian, China. Demographic and clinical data (adjuvant therapy types, histologic types, clinical stage, etc.) were extracted from medical records, and follow-up data were obtained by telephone interviews. We collected 5 to 8 mL of venous blood from all patients for DNA extraction, and rs174549 genotypes were determined by TaqMan assays (Life Technologies, Carlsbad, CA). A Cox proportional hazards model and Kaplan-Meier curve were used to assess the association between FADS1 rs174549 polymorphism and progression-free survival (PFS), as well as overall survival, in oral cancer. Carrying the AA genotype was significantly associated with a decreased risk of PFS: The hazard ratio was 0.52 (95% confidence interval, 0.29 to 0.93) for the codominant model and 0.54 (95% confidence interval, 0.31 to 0.94) for the recessive model. Moreover, better PFS was particularly obvious in patients who had received chemoradiotherapy. A positive multiplicative interaction between FADS1 rs174549 polymorphism and chemoradiotherapy was observed for PFS (P = .036). No significant association was found between FADS1 rs174549 polymorphism and overall survival. Our study suggests, for the first time, that FADS1 rs174549 polymorphism is a potentially independent and favorable factor in predicting oral cancer PFS especially for patients who undergo chemoradiotherapy, and it may serve as a potential target for individualized treatment in the future

Sex-related differences in the enhancing effects of perfluoro-octanoic acid on stearoyl-CoA desaturase and its influence on the acyl composition of phospholipid in rat liver. Comparison with clofibric acid and tiadenol.

PubMed Central

Kawashima, Y; Uy-Yu, N; Kozuka, H

1989-01-01

The effects of the peroxisome proliferators clofibric acid (p-chlorophenoxyisobutyric acid), tiadenol [2,2'-(decamethylenedithio)diethanol] and perfluoro-octanoic acid (PFOA) on hepatic stearoyl-CoA desaturation in male and female rats were compared. Treatment of male rats with the three peroxisome proliferators increased markedly the activity of stearoyl-CoA desaturase. Administration of clofibric acid or tiadenol to female rats increased greatly the hepatic activity of stearoyl-CoA desaturase, the extent of the increases being slightly less pronounced than those of male rats. In contrast with the other two peroxisome proliferators, however, PFOA did not change the activity of stearoyl-CoA desaturase in female rats. Hormonal manipulations revealed that this sex-related difference in the effect of PFOA on stearoyl-CoA desaturase activity is strongly dependent on testosterone. The increase in stearoyl-CoA desaturase activity by peroxisome proliferators was not accompanied by any notable increases in the microsomal content of cytochrome b5 or the activity of NADH: cytochrome b5 reductase. The administration of the peroxisome proliferators greatly altered the acyl composition of hepatic phosphatidylcholine and phosphatidylethanolamine (namely the proportions of C18:1 and C20:3,n-9 fatty acids increased in both phospholipids), and the alterations were partially associated with the increase in stearoyl-CoA desaturase activity. PMID:2574572

Associations between plasma fatty acids, desaturase and elongase, and insulin resistance in children

USDA-ARS?s Scientific Manuscript database

Background and Objectives - Fatty acid profiles, desaturase (SCD-16, SCD018, D5D, D6D) and elongase (ELOVL6) enzyme activity have been associated with adiposity and metabolic disease. While this has been studied in adults, few studies have evaluated children. The objective of this study was to evalu...

Hepatocyte Nuclear Factor 4α (HNF4α) Is a Transcription Factor of Vertebrate Fatty Acyl Desaturase Gene as Identified in Marine Teleost Siganus canaliculatus

PubMed Central

Dong, Yewei; Wang, Shuqi; Chen, Junliang; Zhang, Qinghao; Liu, Yang; You, Cuihong; Monroig, Óscar; Tocher, Douglas R.; Li, Yuanyou

2016-01-01

Rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the capability of biosynthesizing long-chain polyunsaturated fatty acids (LC-PUFA) from C18 precursors, and to possess a Δ4 fatty acyl desaturase (Δ4 Fad) which was the first report in vertebrates, and is a good model for studying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. In order to understand regulatory mechanisms of transcription of Δ4 Fad, the gene promoter was cloned and characterized in the present study. An upstream sequence of 1859 bp from the initiation codon ATG was cloned as the promoter candidate. On the basis of bioinformatic analysis, several binding sites of transcription factors (TF) including GATA binding protein 2 (GATA-2), CCAAT enhancer binding protein (C/EBP), nuclear factor 1 (NF-1), nuclear factor Y (NF-Y), hepatocyte nuclear factor 4α (HNF4α) and sterol regulatory element (SRE), were identified in the promoter by site-directed mutation and functional assays. HNF4α and NF-1 were confirmed to interact with the core promoter of Δ4 Fad by gel shift assay and mass spectrometry. Moreover, over-expression of HNF4α increased promoter activity in HEK 293T cells and mRNA level of Δ4 Fad in rabbitfish primary hepatocytes, respectively. The results indicated that HNF4α is a TF of rabbitfish Δ4 Fad. To our knowledge, this is the first report on promoter structure of a Δ4 Fad, and also the first demonstration of HNF4α as a TF of vertebrate Fad gene involved in transcription regulation of LC-PUFA biosynthesis. PMID:27472219

Maternal fatty acids in pregnancy, FADS polymorphisms, and child intelligence quotient at 8 y of age.

PubMed

Steer, Colin D; Lattka, Eva; Koletzko, Berthold; Golding, Jean; Hibbeln, Joseph R

2013-12-01

Brain tissue is selectively enriched with highly unsaturated fatty acids (FAs). Altering the maternal FA status in pregnancy may improve fetal neural development with lasting consequences for child development. We explored whether maternal FAs in erythrocytes, either measured directly or indirectly by maternal FADS genetic variants, are associated with child intelligence quotient (IQ). Linear regression analyses, adjusted for 18 confounders, were used to investigate the associations in 2839 mother-child pairs from the population-based Avon Longitudinal Study of Parents and Children cohort. Low levels of arachidonic acid (20:4n-6) were associated with lower performance IQ (-2.0 points; 95% CI: -3.5, -0.6 points; P = 0.007, increased R² = 0.27%), high levels of osbond acid (22:5n-6) were associated with verbal IQ (-1.8 points; 95% CI: -3.2, -0.4 points; P = 0.014, R² = 0.20%), and high levels of adrenic acid (22:4n-6) were associated with verbal IQ (-1.7 points; 95% CI:-3.1, -0.3 points; P = 0.016, R² = 0.19%). There was some evidence to support a negative association of low docosahexaenoic acid (DHA; 22:6n-3) with full-scale IQ (R² = 0.15%). Novel weak associations were also observed for low levels of osbond acid (R² ≤ 0.29%) and FADS variants with opposite effects for intron variants and variants in the promoter region such as rs3834458 (R² ≤ 0.38%). These results support the positive role of maternal arachidonic acid and DHA on fetal neural development, although the effects on child IQ by 8 y of age were small (0.1 SD), with other factors contributing more substantially. The endogenous synthesis of these FAs by FADS genes, especially FADS2, may also be important. The replication of these results is recommended.

[The isozymes of stearil-coenzymeA-desaturase and insulin activity in the light of phylogenetic theory of pathology. Oleic fatty acid and realization of biologic functions of trophology and locomotion].

PubMed

2013-11-01

The formation of function of isozymes of stearil-coenzymeA-desaturases occured at the different stages of phylogeny under realization of biologic function of trophology (stearil-coenzymeA-desaturase 1) and biologic function of locomotion, insulin system (stearil-coenzymeA-desaturase 2) billions years later. The stearil-coenzymeA-desaturase 1 transforms in C 18:1 oleic fatty acid only exogenous C 16:0 palmitinic saturated fatty acid. The stearil-coenzymeA-desaturase 2 transforms only endogenic palmitinic saturated fatty acid, synthesized form glucose. The biologic role of insulin is in energy support of biologic function of locomotion. Insulin through expressing stearil-coenzymeA-desaturase 2 transforms energetically non-optimal palmitinic variation of metabolism of substrates into highly effective oleic variation for cells' groundwork of energy (saturated fatty acid and mono fatty acid). The surplus of palmitinic saturated fatty acid in food is enabled in pathogenesis of resistance to insulin and derangement of synthesis of hormone by beta-cells of islets. The resistance to insulin and diabetes mellitus are primarily the derangement of metabolism of saturated fatty acids with mono fatty acids, energy problems of organism and only afterwards the derangement of metabolism of carbohydrates. It is desirable to restrict food intake of exogenous palmitinic saturated fatty acid. The reasons are low expression of independent of insulin stearil-coenzymeA-desaturase 2, marked lipotoxicity of polar form of palmitinic saturated fatty acid and synthesis of non-optimal palmitinic triglycerides instead of physiologic and more energetically more effective oleic triglycerides.

Reassessment of the Genetic Regulation of Fatty Acid Synthesis in Escherichia coli: Global Positive Control by the Dual Functional Regulator FadR

PubMed Central

My, L.; Ghandour Achkar, N.; Viala, J. P.

2015-01-01

ABSTRACT In Escherichia coli, the FadR transcriptional regulator represses the expression of fatty acid degradation (fad) genes. However, FadR is also an activator of the expression of fabA and fabB, two genes involved in unsaturated fatty acid synthesis. Therefore, FadR plays an important role in maintaining the balance between saturated and unsaturated fatty acids in the membrane. We recently showed that FadR also activates the promoter upstream of the fabH gene (L. My, B. Rekoske, J. J. Lemke, J. P. Viala, R. L. Gourse, and E. Bouveret, J Bacteriol 195:3784–3795, 2013, doi:10.1128/JB.00384-13). Furthermore, recent transcriptomic and proteomic data suggested that FadR activates the majority of fatty acid (FA) synthesis genes. In the present study, we tested the role of FadR in the expression of all genes involved in FA synthesis. We found that FadR activates the transcription of all tested FA synthesis genes, and we identified the FadR binding site for each of these genes. This necessitated the reassessment of the transcription start sites for accA and accB genes described previously, and we provide evidence for the presence of multiple promoters driving the expression of these genes. We showed further that regulation by FadR impacts the amount of FA synthesis enzymes in the cell. Our results show that FadR is a global regulator of FA metabolism in E. coli, acting both as a repressor of catabolism and an activator of anabolism, two directly opposing pathways. IMPORTANCE In most bacteria, a transcriptional regulator tunes the level of FA synthesis enzymes. Oddly, such a global regulator still was missing for E. coli, which nonetheless is one of the prominent model bacteria used for engineering biofuel production using the FA synthesis pathway. Our work identifies the FadR functional dual regulator as a global activator of almost all FA synthesis genes in E. coli. Because FadR also is the repressor of FA degradation, FadR acts both as a repressor and an activator

Characterization of Stearoyl-CoA Desaturases from a Psychrophilic Antarctic Copepod, Tigriopus kingsejongensis.

PubMed

Jung, Woongsic; Kim, Eun Jae; Han, Se Jong; Choi, Han-Gu; Kim, Sanghee

2016-10-01

Stearoyl-CoA desaturase is a key regulator in fatty acid metabolism that catalyzes the desaturation of stearic acid to oleic acid and controls the intracellular levels of monounsaturated fatty acids (MUFAs). Two stearoyl-CoA desaturases (SCD, Δ9 desaturases) genes were identified in an Antarctic copepod, Tigriopus kingsejongensis, that was collected in a tidal pool near the King Sejong Station, King George Island, Antarctica. Full-length complementary DNA (cDNA) sequences of two T. kingsejongensis SCDs (TkSCDs) were obtained from next-generation sequencing and isolated by reverse transcription PCR. DNA sequence lengths of the open reading frames of TkSCD-1 and TkSCD-2 were determined to be 1110 and 681 bp, respectively. The molecular weights deduced from the corresponding genes were estimated to be 43.1 kDa (TkSCD-1) and 26.1 kDa (TkSCD-2). The amino acid sequences were compared with those of fatty acid desaturases and sterol desaturases from various organisms and used to analyze the relationships among TkSCDs. As assessed by heterologous expression of recombinant proteins in Escherichia coli, the enzymatic functions of both stearoyl-CoA desaturases revealed that the amount of C16:1 and C18:1 fatty acids increased by greater than 3-fold after induction with isopropyl β-D-thiogalactopyranoside. In particular, C18:1 fatty acid production increased greater than 10-fold in E. coli expressing TkSCD-1 and TkSCD-2. The results of this study suggest that both SCD genes from an Antarctic marine copepod encode a functional desaturase that is capable of increasing the amounts of palmitoleic acid and oleic acid in a prokaryotic expression system.

Molecular cloning and sequence analysis of stearoyl-CoA desaturase in milkfish, Chanos chanos.

PubMed

Hsieh, S L; Liao, W L; Kuo, C M

2001-12-01

Stearoyl-CoA desaturase (EC 1.14.99.5) is a key enzyme in the biosynthesis of polyunsaturated fatty acids and the maintenance of the homeoviscous fluidity of biological membranes. The stearoyl-CoA desaturase cDNA in milkfish (Chanos chanos) was cloned by RT-PCR and RACE, and it was compared with the stearoyl-CoA desaturase in cold-tolerant teleosts, common carp and grass carp. Nucleotide sequence analysis revealed that the cDNA clone has a 972-bp open reading frame encoding 323 amino acid residues. Alignments of the deduced amino acid sequence showed that the milkfish stearoyl-CoA desaturase shares 79% and 75% identity with common carp and grass carp, and 63%-64% with other vertebrates such as sheep, hamsters, rats, mice, and humans. Like common carp and grass carp, the deduced amino acid sequence in milkfish well conserves three histidine cluster motifs (one HXXXXH and two HXXHH) that are essential for catalysis of stearoyl-CoA desaturase activity. However, RT-PCR analysis showed that stearoyl-CoA desaturase expression in milkfish is detected in the tissues of liver, muscle, kidney, brain, and gill, and more expression sites were found in milkfish than in common carp and grass carp. Phylogenic relationships among the deduced stearoyl-CoA desaturase amino acid sequence in milkfish and those in other vertebrates showed that the milkfish stearoyl-CoA desaturase amino acid sequence is phylogenetically closer to those of common carp and grass carp than to other higher vertebrates.

Omega-3 fatty acids: new insights into the pharmacology and biology of docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid.

PubMed

Davidson, Michael H

2013-12-01

Fish oil contains a complex mixture of omega-3 fatty acids, which are predominantly eicosapentaenoic acid (EPA), docosapentaenoic acid, and docosahexaenoic acid (DHA). Each of these omega-3 fatty acids has distinct biological effects that may have variable clinical effects. In addition, plasma levels of omega-3 fatty acids are affected not only by dietary intake, but also by the polymorphisms of coding genes fatty acid desaturase 1-3 for the desaturase enzymes that convert short-chain polyunsaturated fatty acids to long-chain polyunsaturated fatty acids. The clinical significance of this new understanding regarding the complexity of omega-3 fatty acid biology is the purpose of this review. FADS polymorphisms that result in either lower levels of long-chain omega-3 fatty acids or higher levels of long-chain omega-6 polyunsaturated fatty acids, such as arachidonic acid, are associated with dyslipidemia and other cardiovascular risk factors. EPA and DHA have differences in their effects on lipoprotein metabolism, in which EPA, with a more potent peroxisome proliferator-activated receptor-alpha effect, decreases hepatic lipogenesis, whereas DHA not only enhances VLDL lipolysis, resulting in greater conversion to LDL, but also increases HDL cholesterol and larger, more buoyant LDL particles. Overall, these results emphasize that blood concentrations of individual long-chain polyunsaturated fatty acids, which reflect both dietary intake and metabolic influences, may have independent, but also complementary- biological effects and reinforce the need to potentially provide a complex mixture of omega-3 fatty acids to maximize cardiovascular risk reduction.

Regulation of yeast fatty acid desaturase in response to iron deficiency.

PubMed

Romero, Antonia María; Jordá, Tania; Rozès, Nicolas; Martínez-Pastor, María Teresa; Puig, Sergi

2018-06-01

Unsaturated fatty acids (UFA) are essential components of phospholipids that greatly contribute to the biophysical properties of cellular membranes. Biosynthesis of UFAs relies on a conserved family of iron-dependent fatty acid desaturases, whose representative in the model yeast Saccharomyces cerevisiae is Ole1. OLE1 expression is tightly regulated to adapt UFA biosynthesis and lipid bilayer properties to changes in temperature, and in UFA or oxygen availability. Despite iron deficiency being the most extended nutritional disorder worldwide, very little is known about the mechanisms and the biological relevance of fatty acid desaturases regulation in response to iron starvation. In this report, we show that endoplasmic reticulum-anchored transcription factor Mga2 activates OLE1 transcription in response to nutritional and genetic iron deficiencies. Cells lacking MGA2 display low UFA levels and do not grow under iron-limited conditions, unless UFAs are supplemented or OLE1 is overexpressed. The proteasome, E3 ubiquitin ligase Rsp5 and the Cdc48 Npl4/Ufd1 complex are required for OLE1 activation during iron depletion. Interestingly, Mga2 also activates the transcription of its own mRNA in response to iron deficiency, hypoxia, low temperature and low UFAs. MGA2 up-regulation contributes to increase OLE1 expression in these situations. These results reveal the mechanism of OLE1 regulation when iron is scarce and identify the MGA2 auto-regulation as a potential activation strategy in multiple stresses. Copyright © 2018 Elsevier B.V. All rights reserved.

Functional characterization of ExFadLO, an outer membrane protein required for exporting oxygenated long-chain fatty acids in Pseudomonas aeruginosa.

PubMed

Martínez, Eriel; Estupiñán, Mónica; Pastor, F I Javier; Busquets, Montserrat; Díaz, Pilar; Manresa, Angeles

2013-02-01

Bacterial proteins of the FadL family have frequently been associated to the uptake of exogenous hydrophobic substrates. However, their outer membrane location and involvement in substrate uptake have been inferred mainly from sequence similarity to Escherichia coli FadL, the first well-characterized outer membrane transporters of Long-Chain Fatty Acids (LCFAs) in bacteria. Here we report the functional characterization of a Pseudomonas aeruginosa outer membrane protein (ORF PA1288) showing similarities to the members of the FadL family, for which we propose the name ExFadLO. We demonstrate herein that this protein is required to export LCFAs 10-HOME and 7,10-DiHOME, derived from a diol synthase oxygenation activity on oleic acid, from the periplasm to the extracellular medium. Accumulation of 10-HOME and 7,10-DiHOME in the extracellular medium of P. aeruginosa was abolished by a transposon insertion mutation in exFadLO (ExFadLO¯ mutant). However, intact periplasm diol synthase activity was found in this mutant, indicating that ExFadLO participates in the export of these oxygenated LCFAs across the outer membrane. The capacity of ExFadLO¯ mutant to export 10-HOME and 7,10-DiHOME was recovered after complementation with a wild-type, plasmid-expressed ExFadLO protein. A western blot assay with a variant of ExFadLO tagged with a V5 epitope confirmed the location of ExFadLO in the bacterial outer membrane under the experimental conditions tested. Our results provide the first evidence that FadL family proteins, known to be involved in the uptake of hydrophobic substrates from the extracellular environment, also function as secretion elements for metabolites of biological relevance. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Effect of seafood mediated PCB exposure on desaturase activity and PUFA profile in Faroese septuagenarians.

PubMed

Tøttenborg, Sandra Søgaard; Choi, Anna L; Bjerve, Kristian S; Weihe, Pal; Grandjean, Philippe

2015-07-01

Polychlorinated biphenyl (PCB) exposure may affect serum concentrations of polyunsaturated fatty acids (PUFAs) by inhibiting desaturases ∆5 and ∆6 that drive their synthesis from precursor fatty acids. Such changes in the composition of fatty acids may affect cardiovascular disease risk, which is thought to increase at elevated PCB exposures. This population-based cross-sectional study examined 712 Faroese men and women aged 70-74 years. The serum phospholipid fraction of fasting blood samples was used to determine the PUFA profile, including linoleic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosatrienoic acid, and other relevant fatty acids. Ratios between precursor and metabolite fatty acids were used as proxies for ∆5 and ∆6 desaturase activity. Tertiles of serum-PCB concentrations were used in multiple regression analyses to determine the association between the exposure and desaturase activity. In multiple regression models, PCB exposure was inversely related to the estimated Δ6 desaturase activity resulting in accumulation of precursor fatty acids and decrease in the corresponding product PUFAs. A positive association between PCB and Δ5 desaturation was also found. A relative increase in EA was also observed, though only in the third tertile of PCB exposure. Non-linear relationships between the exposure and the desaturase activity were not found. Consuming fish and seafood may not be translated into beneficial fatty acid profiles if the diet simultaneously causes exposure to PCBs. Although the desaturase estimates were likely influenced by dietary intakes of product PUFAs, the association between PCB exposure and ∆6 desaturase activity is plausible and may affect cardiovascular disease risk. Copyright © 2015 Elsevier Inc. All rights reserved.

Expression and evolution of delta9 and delta11 desaturase genes in the moth Spodoptera littoralis.

PubMed

Rodríguez, Sergio; Hao, Guixia; Liu, Weitian; Piña, Benjamín; Rooney, Alejandro P; Camps, Francisco; Roelofs, Wendell L; Fabriàs, Gemma

2004-12-01

Desaturation of fatty acids is a key reaction in the biosynthesis of moth sex pheromones. The main component of Spodoptera littoralis sex pheromone blend is produced by the action of Delta11 and Delta9 desaturases. In this article, we report on the cloning of four desaturase-like genes in this species: one from the fat body (Sls-FL1) and three (Sls-FL2, Sls-FL3 and Sls-FL4) from the pheromone gland. By means of a computational/phylogenetic method, as well as functional assays, the desaturase gene products have been characterized. The fat body gene expressed a Delta9 desaturase that produced (Z)-9-hexadecenoic and (Z)-9-octadecenoic acids in a (1:4.5) ratio, whereas the pheromone gland Sls-FL2 expressed a Delta9 desaturase that produced (Z)-9-hexadecenoic and (Z)-9-octadecenoic acids in a (1.5:1) ratio. Although both Delta9 desaturases produced (Z)-9-tetradecenoic acid from myristic acid, transformed yeast grown in the presence of a mixture of myristic and (E)-11-tetradecenoic acids produced (Z,E)-9,11-tetradecadienoic acid, but not (Z)-9-tetradecenoic acid. The Sls-FL3 gene expressed a protein that produced a mixture of (E)-11-tetradecenoic, (Z)-11-tetradecenoic, (Z)-11-hexadecenoic and (Z)-11-octadecenoic acids in a 5:4:60:31 ratio. Despite having all the characteristics of a desaturase gene, no function could be found for Sls-FL4.

Plasma lipid fatty acid composition, desaturase activities and insulin sensitivity in Amerindian women.

PubMed

Vessby, B; Ahrén, B; Warensjö, E; Lindgärde, F

2012-03-01

Two Amerindian populations--Shuar women living in the Amazonian rain forest under traditional conditions and urbanized women in a suburb of Lima were studied. The fatty acid composition in plasma lipids and the relationships between fatty acid composition and metabolic variables were studied, as well as in a reference group of Swedish women. Fasting plasma was used for analyses of glucose, insulin, leptin and fatty acid composition. Women in Lima had more body fat, higher fasting insulin and leptin and lower insulin sensitivity than the Shuar women, who had insulin sensitivity similar to Swedish women. Shuar women had very high proportions (mean; SD) of palmitoleic (13.2; 3.9%) and oleic (33.9; 3.7%) acids in the plasma cholesteryl esters with very low levels of linoleic acid (29.1; 6.1 3%), as expected on a low fat, high carbohydrate diet. The estimated activity of delta 9 (SCD-1) desaturase was about twice as high in the Shuar compared with Lima women, suggesting neo lipogenesis, while the delta 5 desaturase activity did not differ. The Lima women, as well as the Swedish, showed strong positive correlations between SCD-1 activity on the one hand and fasting insulin and HOMA index on the other. These associations were absent in the Shuar women. The high SCD-1 activity in the Shuar women may reflect increased lipogenesis in adipose tissue. It also illustrates how a low fat diet rich in non-refined carbohydrates can be linked to a good metabolic situation. Copyright © 2010. Published by Elsevier B.V.

Use of 5-deazaFAD to study hydrogen transfer in the D-amino acid oxidase reaction.

PubMed

Hersh, L B; Jorns, M S

1975-11-25

The apoprotein of hog kidney D-amino acid oxidase was reconstituted with 5-deazaflavin adenine dinucleotide (5-deazaFAD) to yield a protein which contains 1.5 mol of 5-deazaFAD/mol of enzyme. The deazaFAD-containing enzyme forms complexes with benzoate, 2-amino benzoate, and 4-aminobenzoate which are both qualitatively and quantitatively similar to those observed with native enzyme. The complex with 2-aminobenzoate exhibits a new long wavelength absorption band characteristic of a flavin charge-transfer complex. The reconstituted enzyme exhibits no activity when assayed by D-alanine oxidation. However, the bound chromophore can be reduced by alanine, phenylalanine, proline, methionine, and valine, but not by glutamate or aspartate, indicating the deazaFAD enzyme retains the substrate specificity of the native enzyme. Reduction of the enzyme by D-alanine exhibits a 1.6-fold deuterium isotope effect. Reoxidation of the reduced enzyme occurred in the presence of pyruvate plus ammonia, but not with pyruvate alone or ammonia alone. beta-Phenylpyruvate and alpha-ketobutyrate, but not alpha-ketoglutarate could replace pyruvate. Reduced enzyme isolated following reaction with [alpha-3H]alanine was found to contain 0.5 mol of tritium/mol of deazaFADH2. After denaturation of the tritium-labeled enzyme, the radioactivity was identified as deazaFADH2. Reaction of the reduced tritium-labeled enzyme with pyruvate plus ammonia prior to denaturation yields [alpha-3H]alanine and unlabeled deazaFAD. These results suggest that reduction and reoxidation of enzyme-bound deazaFAD involves the stereo-specific transfer of alpha-hydrogen from substrate to deazaFAD.

A High-Fat, High-Oleic Diet, But Not a High-Fat, Saturated Diet, Reduces Hepatic α-Linolenic Acid and Eicosapentaenoic Acid Content in Mice.

PubMed

Picklo, Matthew J; Murphy, Eric J

2016-05-01

Considerable research has focused upon the role of linoleic acid (LNA; 18:2n-6) as a competitive inhibitor of α-linolenic (ALA; 18:3n-3) metabolism; however, little data exist as to the impact of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) on ALA metabolism. We tested the hypothesis that a high SFA diet, compared to a high MUFA (oleic acid 18:1n-9) diet, reduces ALA conversion to long chain n-3 fatty acids. Mice were fed for 12 weeks on three diets: (1) a control, 16 % fat energy diet consisting of similar levels of SFA and MUFA (2) a 50 % fat energy high MUFA energy diet (35 % MUFA and 7 % SFA) or (3) a 50 % fat energy, high SFA energy diet (34 % SFA, 8 % MUFA). ALA and LNA content remained constant. Analysis of hepatic lipids demonstrated a selective reduction (40 %) in ALA but not LNA and a 35 % reduction in eicosapentaenoic acid (EPA; 20:5n-3) in the high MUFA mice compared to the other groups. Lower content of ALA was reflected in the neutral lipid fraction, while smaller levels of phospholipid esterified EPA and docosapentaenoic acid (DPA; 22:5n-3) were evident. Docosahexaenoic acid (DHA; 22:6n-3) content was elevated by the high SFA diet. Expression of Fads1 (Δ5 desaturase) and Fads2 (Δ6 desaturase) was elevated by the high MUFA and reduced by the high SFA diet. These data indicate that a high MUFA diet, but not a high SFA diet, reduces ALA metabolism and point to selective hepatic disposition of ALA versus LNA.

Increasing dietary EPA and DHA influence estimated fatty acid desaturase activity in systemic organs which is reflected in the red blood cell in mice.

PubMed

Davidson, Emily A; Pickens, C Austin; Fenton, Jenifer I

2018-03-01

Delta-5 (D5D) and delta-6 (D6D) desaturase are key enzymes in fatty acid (FA) metabolism. Dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may alter tissue FA composition via D5D and D6D. The purpose was to determine the relationship between dietary EPA + DHA, estimated desaturase activities of various tissues and the reflection of desaturase activity in the red blood cell (RBC). Mice were fed diets with increasing percent of energy from EPA + DHA. Phospholipid FA composition of heart, muscle, spleen, lung, adipose tissues and RBC were analysed. D5D and D6D enzyme activity estimates (EAE) were calculated as the ratio of 20:4/20:3 and 20:3/18:2, respectively. D5D EAE decreased in all tissues, except muscle, with increasing dietary EPA + DHA. RBC D5D EAE positively correlated with D5D EAE in all tissues. RBC D6D EAE positively correlated with muscle and inversely correlated with adipose D6D EAE. Our findings suggest differential influence of dietary EPA + DHA upon tissue desaturase activities.

Positive Selection on a Regulatory Insertion–Deletion Polymorphism in FADS2 Influences Apparent Endogenous Synthesis of Arachidonic Acid

PubMed Central

Kothapalli, Kumar S. D.; Ye, , Kaixiong; Gadgil, Maithili S.; Carlson, Susan E.; O’Brien, Kimberly O.; Zhang, Ji Yao; Park, Hui Gyu; Ojukwu, Kinsley; Zou, James; Hyon, Stephanie S.; Joshi, Kalpana S.; Gu, Zhenglong; Keinan, Alon; Brenna, J.Thomas

2016-01-01

Long chain polyunsaturated fatty acids (LCPUFA) are bioactive components of membrane phospholipids and serve as substrates for signaling molecules. LCPUFA can be obtained directly from animal foods or synthesized endogenously from 18 carbon precursors via the FADS2 coded enzyme. Vegans rely almost exclusively on endogenous synthesis to generate LCPUFA and we hypothesized that an adaptive genetic polymorphism would confer advantage. The rs66698963 polymorphism, a 22-bp insertion–deletion within FADS2, is associated with basal FADS1 expression, and coordinated induction of FADS1 and FADS2 in vitro. Here, we determined rs66698963 genotype frequencies from 234 individuals of a primarily vegetarian Indian population and 311 individuals from the US. A much higher I/I genotype frequency was found in Indians (68%) than in the US (18%). Analysis using 1000 Genomes Project data confirmed our observation, revealing a global I/I genotype of 70% in South Asians, 53% in Africans, 29% in East Asians, and 17% in Europeans. Tests based on population divergence, site frequency spectrum, and long-range haplotype consistently point to positive selection encompassing rs66698963 in South Asian, African, and some East Asian populations. Basal plasma phospholipid arachidonic acid (ARA) status was 8% greater in I/I compared with D/D individuals. The biochemical pathway product–precursor difference, ARA minus linoleic acid, was 31% and 13% greater for I/I and I/D compared with D/D, respectively. This study is consistent with previous in vitro data suggesting that the insertion allele enhances n-6 LCPUFA synthesis and may confer an adaptive advantage in South Asians because of the traditional plant-based diet practice. PMID:27188529

Stearoyl-CoA desaturase expression and fatty acid composition in milkfish (Chanos chanos) and grass carp (Ctenopharyngodon idella) during cold acclimation.

PubMed

Hsieh, S L; Kuo, C-M

2005-05-01

Desaturation of fatty acids is an important adaptation mechanism for fish to maintain membrane fluidity under thermal stress. To comprehend the temperature adaptation mechanism in fish, we investigated the difference in the changes of stearoyl-CoA desaturase expression and fatty acid composition between milkfish and grass carp under cold acclimation. We find that in both fish the proportions of unsaturated fatty acids at 15 degrees C are all higher than those at 25 degrees C. In milkfish Delta(9)-desaturation index (ratios of 16:1/16:0 and 18:1/18:0) increases significantly in the beginning of cold acclimation at 15 degrees C and decreases afterward, but in grass carp it increases slightly in the beginning of cold acclimation followed by a sustained dramatic increase. Similarly, activity of stearoyl-CoA desaturase in milkfish increases significantly in the beginning, peaks at day 4, and then decreases constantly, but in grass carp it increases gradually in the first week, rises dramatically afterward, and then maintains a very high level. The change of stearoyl-CoA desaturase activity is parallel to the change of Delta(9)-desaturation index in both milkfish and grass carp, but it is one day earlier than Delta(9)-desaturation index in milkfish. The difference of adaptation capability between milkfish and grass carp under cold stress is further evidenced by RT-PCR and Northern blot analysis of stearoyl-CoA desaturase gene expression.

OeFAD8, OeLIP and OeOSM expression and activity in cold-acclimation of Olea europaea, a perennial dicot without winter-dormancy.

PubMed

D'Angeli, Simone; Matteucci, Maya; Fattorini, Laura; Gismondi, Angelo; Ludovici, Matteo; Canini, Antonella; Altamura, Maria Maddalena

2016-05-01

Cold-acclimation genes in woody dicots without winter-dormancy, e.g., olive-tree, need investigation. Positive relationships between OeFAD8, OeOSM , and OeLIP19 and olive-tree cold-acclimation exist, and couple with increased lipid unsaturation and cutinisation. Olive-tree is a woody species with no winter-dormancy and low frost-tolerance. However, cold-tolerant genotypes were empirically selected, highlighting that cold-acclimation might be acquired. Proteins needed for olive-tree cold-acclimation are unknown, even if roles for osmotin (OeOSM) as leaf cryoprotectant, and seed lipid-transfer protein for endosperm cutinisation under cold, were demonstrated. In other species, FAD8, coding a desaturase producing α-linolenic acid, is activated by temperature-lowering, concomitantly with bZIP-LIP19 genes. The research was focussed on finding OeLIP19 gene(s) in olive-tree genome, and analyze it/their expression, and that of OeFAD8 and OeOSM, in drupes and leaves under different cold-conditions/developmental stages/genotypes, in comparison with changes in unsaturated lipids and cell wall cutinisation. Cold-induced cytosolic calcium transients always occurred in leaves/drupes of some genotypes, e.g., Moraiolo, but ceased in others, e.g., Canino, at specific drupe stages/cold-treatments, suggesting cold-acclimation acquisition only in the latter genotypes. Canino and Moraiolo were selected for further analyses. Cold-acclimation in Canino was confirmed by an electrolyte leakage from leaf/drupe membranes highly reduced in comparison with Moraiolo. Strong increases in fruit-epicarp/leaf-epidermis cutinisation characterized cold-acclimated Canino, and positively coupled with OeOSM expression, and immunolocalization of the coded protein. OeFAD8 expression increased with cold-acclimation, as the production of α-linolenic acid, and related compounds. An OeLIP19 gene was isolated. Its levels changed with a trend similar to OeFAD8. All together, results sustain a positive

Synthesis of docosahexaenoic acid from eicosapentaenoic acid in retina neurons protects photoreceptors from oxidative stress

PubMed Central

Simón, María Victoria; Agnolazza, Daniela L.; German, Olga Lorena; Garelli, Andrés; Politi, Luis E.; Agbaga, Martin-Paul; Anderson, Robert E.; Rotstein, Nora P.

2015-01-01

Oxidative stress is involved in activating photoreceptor death in several retinal degenerations. Docosahexaenoic acid (DHA), the major polyunsaturated fatty acid in the retina, protects cultured retina photoreceptors from apoptosis induced by oxidative stress and promotes photoreceptor differentiation. Here we investigated whether eicosapentaenoic acid (EPA), a metabolic precursor to DHA, had similar effects and whether retinal neurons could metabolize EPA to DHA. Adding EPA to rat retina neuronal cultures increased opsin expression and protected photoreceptors from apoptosis induced by the oxidants paraquat (PQ) and hydrogen peroxide (H2O2). Palmitic, oleic, and arachidonic acids had no protective effect, showing the specificity for DHA. We found that EPA supplementation significantly increased DHA percentage in retinal neurons, but not EPA percentage. Photoreceptors and glial cells expressed Δ6 desaturase (FADS2), which introduces the last double bond in DHA biosynthetic pathway. Pre-treatment of neuronal cultures with CP-24879 hydrochloride, a Δ5/Δ6 desaturase inhibitor, prevented EPA-induced increase in DHA percentage and completely blocked EPA protection and its effect on photoreceptor differentiation. These results suggest that EPA promoted photoreceptor differentiation and rescued photoreceptors from oxidative stress-induced apoptosis through its elongation and desaturation to DHA. Our data show, for the first time, that isolated retinal neurons can synthesize DHA in culture. PMID:26662863

Conjugated fatty acid synthesis: residues 111 and 115 influence product partitioning of Momordica charantia conjugase.

PubMed

Rawat, Richa; Yu, Xiao-Hong; Sweet, Marie; Shanklin, John

2012-05-11

Conjugated linolenic acids (CLNs), 18:3 Δ(9,11,13), lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ(9,12,15)). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ(9cis,11trans,13cis)) or α-eleostearic acid (18:3 Δ(9cis,11trans,13trans)). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation.

Biosynthesis of Polyunsaturated Fatty Acids in Octopus vulgaris: Molecular Cloning and Functional Characterisation of a Stearoyl-CoA Desaturase and an Elongation of Very Long-Chain Fatty Acid 4 Protein

PubMed Central

Monroig, Óscar; de Llanos, Rosa; Varó, Inmaculada; Hontoria, Francisco; Tocher, Douglas R.; Puig, Sergi; Navarro, Juan C.

2017-01-01

Polyunsaturated fatty acids (PUFAs) have been acknowledged as essential nutrients for cephalopods but the specific PUFAs that satisfy the physiological requirements are unknown. To expand our previous investigations on characterisation of desaturases and elongases involved in the biosynthesis of PUFAs and hence determine the dietary PUFA requirements in cephalopods, this study aimed to investigate the roles that a stearoyl-CoA desaturase (Scd) and an elongation of very long-chain fatty acid 4 (Elovl4) protein play in the biosynthesis of essential fatty acids (FAs). Our results confirmed the Octopus vulgaris Scd is a ∆9 desaturase with relatively high affinity towards saturated FAs with ≥ C18 chain lengths. Scd was unable to desaturate 20:1n-15 (∆520:1) suggesting that its role in the biosynthesis of non-methylene interrupted FAs (NMI FAs) is limited to the introduction of the first unsaturation at ∆9 position. Interestingly, the previously characterised ∆5 fatty acyl desaturase was indeed able to convert 20:1n-9 (∆1120:1) to ∆5,1120:2, an NMI FA previously detected in octopus nephridium. Additionally, Elovl4 was able to mediate the production of 24:5n-3 and thus can contribute to docosahexaenoic acid (DHA) biosynthesis through the Sprecher pathway. Moreover, the octopus Elovl4 was confirmed to play a key role in the biosynthesis of very long-chain (>C24) PUFAs. PMID:28335553

Biosynthesis of Polyunsaturated Fatty Acids in Octopus vulgaris: Molecular Cloning and Functional Characterisation of a Stearoyl-CoA Desaturase and an Elongation of Very Long-Chain Fatty Acid 4 Protein.

PubMed

Monroig, Óscar; de Llanos, Rosa; Varó, Inmaculada; Hontoria, Francisco; Tocher, Douglas R; Puig, Sergi; Navarro, Juan C

2017-03-21

Polyunsaturated fatty acids (PUFAs) have been acknowledged as essential nutrients for cephalopods but the specific PUFAs that satisfy the physiological requirements are unknown. To expand our previous investigations on characterisation of desaturases and elongases involved in the biosynthesis of PUFAs and hence determine the dietary PUFA requirements in cephalopods, this study aimed to investigate the roles that a stearoyl-CoA desaturase (Scd) and an elongation of very long-chain fatty acid 4 (Elovl4) protein play in the biosynthesis of essential fatty acids (FAs). Our results confirmed the Octopus vulgaris Scd is a ∆9 desaturase with relatively high affinity towards saturated FAs with ≥ C 18 chain lengths. Scd was unable to desaturate 20:1 n- 15 ( ∆5 20:1) suggesting that its role in the biosynthesis of non-methylene interrupted FAs (NMI FAs) is limited to the introduction of the first unsaturation at ∆9 position. Interestingly, the previously characterised ∆5 fatty acyl desaturase was indeed able to convert 20:1 n- 9 ( ∆11 20:1) to ∆5,11 20:2, an NMI FA previously detected in octopus nephridium. Additionally, Elovl4 was able to mediate the production of 24:5 n- 3 and thus can contribute to docosahexaenoic acid (DHA) biosynthesis through the Sprecher pathway. Moreover, the octopus Elovl4 was confirmed to play a key role in the biosynthesis of very long-chain (>C 24 ) PUFAs.

Genome-wide association study of plasma polyunsaturated fatty acids in the InCHIANTI Study.

PubMed

Tanaka, Toshiko; Shen, Jian; Abecasis, Gonçalo R; Kisialiou, Aliaksei; Ordovas, Jose M; Guralnik, Jack M; Singleton, Andrew; Bandinelli, Stefania; Cherubini, Antonio; Arnett, Donna; Tsai, Michael Y; Ferrucci, Luigi

2009-01-01

Polyunsaturated fatty acids (PUFA) have a role in many physiological processes, including energy production, modulation of inflammation, and maintenance of cell membrane integrity. High plasma PUFA concentrations have been shown to have beneficial effects on cardiovascular disease and mortality. To identify genetic contributors of plasma PUFA concentrations, we conducted a genome-wide association study of plasma levels of six omega-3 and omega-6 fatty acids in 1,075 participants in the InCHIANTI study on aging. The strongest evidence for association was observed in a region of chromosome 11 that encodes three fatty acid desaturases (FADS1, FADS2, FADS3). The SNP with the most significant association was rs174537 near FADS1 in the analysis of arachidonic acid (AA; p = 5.95 x 10(-46)). Minor allele homozygotes had lower AA compared to the major allele homozygotes and rs174537 accounted for 18.6% of the additive variance in AA concentrations. This SNP was also associated with levels of eicosadienoic acid (EDA; p = 6.78 x 10(-9)) and eicosapentanoic acid (EPA; p = 1.07 x 10(-14)). Participants carrying the allele associated with higher AA, EDA, and EPA also had higher low-density lipoprotein (LDL-C) and total cholesterol levels. Outside the FADS gene cluster, the strongest region of association mapped to chromosome 6 in the region encoding an elongase of very long fatty acids 2 (ELOVL2). In this region, association was observed with EPA (rs953413; p = 1.1 x 10(-6)). The effects of rs174537 were confirmed in an independent sample of 1,076 subjects participating in the GOLDN study. The ELOVL2 SNP was associated with docosapentanoic and DHA but not with EPA in GOLDN. These findings show that polymorphisms of genes encoding enzymes in the metabolism of PUFA contribute to plasma concentrations of fatty acids.

Botanical oils enriched in n-6 and n-3 FADS2 products are equally effective in preventing atherosclerosis and fatty liver.

PubMed

Shewale, Swapnil V; Boudyguina, Elena; Zhu, Xuewei; Shen, Lulu; Hutchins, Patrick M; Barkley, Robert M; Murphy, Robert C; Parks, John S

2015-06-01

Echium oil (EO), which is enriched in 18:4 n-3, the immediate product of fatty acid desaturase 2 (FADS2) desaturation of 18:3 n-3, is as atheroprotective as fish oil (FO). The objective of this study was to determine whether botanical oils enriched in the FADS2 products 18:3 n-6 versus 18:4 n-3 are equally atheroprotective. LDL receptor KO mice were fed one of four atherogenic diets containing 0.2% cholesterol and 10% calories as palm oil (PO) plus 10% calories as: 1) PO; 2) borage oil (BO; 18:3 n-6 enriched); 3) EO (18:4 n-3 enriched); or 4) FO for 16 weeks. Mice fed BO, EO, and FO versus PO had significantly lower plasma total and VLDL cholesterol concentrations; hepatic neutral lipid content and inflammation, aortic CE content, aortic root intimal area and macrophage content; and peritoneal macrophage inflammation, CE content, and ex vivo chemotaxis. Atheromas lacked oxidized CEs despite abundant generation of macrophage 12/15 lipooxygenase-derived metabolites. We conclude that botanical oils enriched in 18:3 n-6 and 18:4 n-3 PUFAs beyond the rate-limiting FADS2 enzyme are equally effective in preventing atherosclerosis and hepatosteatosis compared with saturated/monounsaturated fat due to cellular enrichment of ≥20 PUFAs, reduced plasma VLDL, and attenuated macrophage inflammation. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator's Sex Pheromone.

PubMed

Sedeek, Khalid E M; Whittle, Edward; Guthörl, Daniela; Grossniklaus, Ueli; Shanklin, John; Schlüter, Philipp M

2016-06-06

Mimicry illustrates the power of selection to produce phenotypic convergence in biology [1]. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species [2-4]. This involves mimicry of visual, tactile, and chemical signals of females [2-7], especially their sex pheromones [8-11]. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius [11-13]. A difference in alkene double-bond positions is responsible for reproductive isolation between O. exaltata and closely related species, such as O. sphegodes [13-16]. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5's reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. This change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Regulated expression of a repressor protein: FadR activates iclR.

PubMed Central

Gui, L; Sunnarborg, A; LaPorte, D C

1996-01-01

The control of the glyoxylate bypass operon (aceBAK) of Escherichia coli is mediated by two regulatory proteins, IclMR and FadR. IclMR is a repressor protein which has previously been shown to bind to a site which overlaps the aceBAK promoter. FAR is a repressor/activator protein which participates in control of the genes of fatty acid metabolism. A sequence just upstream of the iclR promoter bears a striking resemblance to FadR binding sites found in the fatty acid metabolic genes. The in vitro binding specificity of FadR, determined by oligonucleotide selection, was in good agreement with the sequences of these sites. The ability of FadR to bind to the site associated with iclR was demonstrated by gel shift and DNase I footprint analyses. Disruption of FadR or inactivation of the FadR binding site of iclR decreased the expression of an iclR::lacZ operon fusion, indicating that FadR activates the expression of iclR. It has been reported that disruption of fadR increases the expression of aceBAK. We observed a similar increase when we inactivated the FadR binding site of an iclR+ allele. This result suggests that FadR regulates aceBAK indirectly by altering the expression of IclR. PMID:8755903

Effect of feeding lambs with a tanniferous shrub (rockrose) and a vegetable oil blend on fatty acid composition of meat lipids.

PubMed

Francisco, A; Alves, S P; Portugal, P V; Pires, V M R; Dentinho, M T; Alfaia, C M; Jerónimo, E; Prates, J A M; Santos-Silva, J; Bessa, R J B

2016-12-01

The effects of feeding Cistus ladanifer (Cistus) and a blend of soybean and linseed oil (1 : 2 vol/vol) on fatty acid (FA) composition of lamb meat lipids and messenger RNA (mRNA) expression of desaturase enzymes was assessed. In total, 54 male lambs were randomly assigned to 18 pens and to nine diets, resulting from the combination of three inclusion levels of Cistus (50 v. 100 v. 200 g/kg of dry matter (DM)) and three inclusion levels of oil (0 v. 40 v. 80 g/kg of DM). The forage-to-concentrate ratio of the diets was 1 : 1. Longissimus muscle lipids were extracted, fractionated into neutral (NL) and polar lipid (PL) and FA methyl esters obtained and analyzed by GLC. The expression of genes encoding Δ5, Δ6 and Δ9 desaturases (fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and stearoyl CoA desaturase (SCD)) was determined. Intramuscular fat, NL and PL contents were not affected by oil or Cistus. Oil supplementation reduced (P<0.05) 16:0, c9-16:1, 17:0, c9-17:1 and c9-18:1 FA and increased (P<0.05) 18:2n-6, 18:3n-3 and the majority of biohydrogenation intermediates in NL. Cistus alone had few effects on FA of NL but interacted with oil (P<0.05) by increasing t10-18:1,t10,t12-18:2,t10,c12-18:2 and t7,c9-18:2. The t10-/t11-18:1 ratio increased with both Cistus and oil levels. The c9, t11-18:2 did not increase (P<0.05) with both oil and Cistus dietary inclusion. Oil reduced c9-16:1, 17:0, c9-17:1,c9-18:1, 20:4n-6, 22:4n-6 and 20:3n-9 proportions in PL, and increased 18:2n-6, 18:3n-3, 20:3n-3 and of most of the biohydrogenation intermediates. The Cistus had only minor effects on FA composition of PL. Cistus resulted in a reduction (P<0.05) of 20:5n-3 and 22:6n-3 in the meat PL. The expression level of SCD mRNA increased (P=0.015) with Cistus level, although a linear relationship with condensed tannins intake (P=0.11) could not be established. FADS1 mRNA expressed levels increased linearly (P=0.019) with condensed tannins intake. In summary, the

Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species.

PubMed

Zheng, X; Seiliez, I; Hastings, N; Tocher, D R; Panserat, S; Dickson, C A; Bergot, P; Teale, A J

2004-10-01

Fish are the most important dietary source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), that have particularly important roles in human nutrition reflecting their roles in critical physiological processes. The objective of the study described here was to clone, functionally characterize and compare expressed fatty acid desaturase genes involved in the production of EPA and DHA in freshwater and marine teleost fish species. Putative fatty acid desaturase cDNAs were isolated and cloned from common carp (Cyprinus carpio) and turbot (Psetta maximus). The enzymic activities of the products of these cDNAs, together with those of cDNAs previously cloned from rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata), were determined by heterologous expression in the yeast Saccharomyces cerevisiae. The carp and turbot desaturase cDNAs included open reading frames (ORFs) of 1335 and 1338 base pairs, respectively, specifying proteins of 444 and 445 amino acids. The protein sequences possessed all the characteristic features of microsomal fatty acid desaturases, including three histidine boxes, two transmembrane regions, and N-terminal cytochrome b(5) domains containing the haem-binding motif, HPGG. Functional expression showed all four fish cDNAs encode basically unifunctional Delta6 fatty acid desaturase enzymes responsible for the first and rate-limiting step in the biosynthesis of HUFA from 18:3n-3 and 18:2n-6. All the fish desaturases were more active towards the n-3 substrate with 59.5%, 31.5%, 23.1% and 7.0% of 18:3n-3 being converted to 18:4n-3 in the case of turbot, trout, sea bream and carp, respectively. The enzymes also showed very low, probably physiologically insignificant, levels of Delta5 desaturase activity, but none of the products showed Delta4 desaturase activity. The cloning and characterization of desaturases from these fish is an important advance, as they are species in which

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator’s Sex Pheromone

DOE PAGES

Sedeek, Khalid E. M.; Whittle, Edward; Guthörl, Daniela; ...

2016-05-19

Here, we show that mimicry illustrates the power of selection to produce phenotypic convergence in biology. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species. This involves mimicry of visual, tactile, and chemical signals of females, especially their sex pheromones. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius. A difference in alkene double-bond positions is responsible for reproductivemore » isolation between O. exaltata and closely related species, such as O. sphegodes. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5’s reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. In conclusion, this change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution.« less

Amino Acid Change in an Orchid Desaturase Enables Mimicry of the Pollinator’s Sex Pheromone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sedeek, Khalid E. M.; Whittle, Edward; Guthörl, Daniela

Here, we show that mimicry illustrates the power of selection to produce phenotypic convergence in biology. A striking example is the imitation of female insects by plants that are pollinated by sexual deception of males of the same insect species. This involves mimicry of visual, tactile, and chemical signals of females, especially their sex pheromones. The Mediterranean orchid Ophrys exaltata employs chemical mimicry of cuticular hydrocarbons, particularly the 7-alkenes, in an insect sex pheromone to attract and elicit mating behavior in its pollinators, males of the cellophane bee Colletes cunicularius. A difference in alkene double-bond positions is responsible for reproductivemore » isolation between O. exaltata and closely related species, such as O. sphegodes. We show that these 7-alkenes are likely determined by the action of the stearoyl-acyl-carrier-protein desaturase (SAD) homolog SAD5. After gene duplication, changes in subcellular localization relative to the ancestral housekeeping desaturase may have allowed proto-SAD5’s reaction products to undergo further biosynthesis to both 7- and 9-alkenes. Such ancestral coproduction of two alkene classes may have led to pollinator-mediated deleterious pleiotropy. Despite possible evolutionary intermediates with reduced activity, amino acid changes at the bottom of the substrate-binding cavity have conferred enzyme specificity for 7-alkene biosynthesis by preventing the binding of longer-chained fatty acid (FA) precursors by the enzyme. In conclusion, this change in desaturase function enabled the orchid to perfect its chemical mimicry of pollinator sex pheromones by escape from deleterious pleiotropy, supporting a role of pleiotropy in determining the possible trajectories of adaptive evolution.« less

Genetic variants in the metabolism of omega-6 and omega-3 fatty acids: their role in the determination of nutritional requirements and chronic disease risk.

PubMed

Simopoulos, Artemis P

2010-07-01

The tissue composition of polyunsaturated fatty acids is important to health and depends on both dietary intake and metabolism controlled by genetic polymorphisms that should be taken into consideration in the determination of nutritional requirements. Therefore at the same dietary intake of linoleic acid (LA) and alpha-linolenic acid (ALA), their respective health effects may differ due to genetic differences in metabolism. Delta-5 and delta-6 desaturases, FADS1 and FADS2, respectively, influence the serum, plasma and membrane phospholipid levels of LA, ALA and long-chain polyunsaturated fatty acids during pregnancy, lactation, and may influence an infant's IQ, atopy and coronary heart disease (CHD) risk. At low intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), polymorphisms at the 5-lipoxygenase (5-LO) level increase the risk for CHD whereas polymorphisms at cyclooxgenase-2 increase the risk for prostate cancer. At high intakes of LA the risk for breast cancer increases. EPA and DHA influence gene expression. In future, intervention studies on the biological effects of LA, ALA and LC-PUFAs, and the effects of genetic variants in FADS1 and FADS2, 5-LO and cyclooxygenase-2 should be taken into consideration both in the determination of nutritional requirements and chronic disease risk. Furthermore, genome-wide association studies need to include environmental exposures and include diet in the interaction between genetic variation and disease association.

Multiplex PCR assay for detection of recombinant genes encoding fatty acid desaturases fused with lichenase reporter protein in GM plants.

PubMed

Berdichevets, Iryna N; Shimshilashvili, Hristina R; Gerasymenko, Iryna M; Sindarovska, Yana R; Sheludko, Yuriy V; Goldenkova-Pavlova, Irina V

2010-07-01

Thermostable lichenase encoded by licB gene of Clostridium thermocellum can be used as a reporter protein in plant, bacterial, yeast, and mammalian cells. It has important advantages of high sensitivity and specificity in qualitative and quantitative assays. Deletion variants of LicB (e.g., LicBM3) retain its enzymatic activity and thermostability and can be expressed in translational fusion with target proteins without compromising with their properties. Fusion with the lichenase reporter is especially convenient for the heterologous expression of proteins whose analysis is difficult or compromised by host enzyme activities, as it is in case of fatty acid desaturases occurring in all groups of organisms. Recombinant desaturase-lichenase genes can be used for creating genetically modified (GM) plants with improved chill tolerance. Development of an analytical method for detection of fused desaturase-lichenase transgenes is necessary both for production of GM plants and for their certification. Here, we report a multiplex polymerase chain reaction method for detection of desA and desC desaturase genes of cyanobacteria Synechocystis sp. PCC6803 and Synechococcus vulcanus, respectively, fused to licBM3 reporter in GM plants.

Remote control of regioselectivity in acyl-acyl carrier protein-desaturases.

PubMed

Guy, Jodie E; Whittle, Edward; Moche, Martin; Lengqvist, Johan; Lindqvist, Ylva; Shanklin, John

2011-10-04

Regiospecific desaturation of long-chain saturated fatty acids has been described as approaching the limits of the discriminatory power of enzymes because the substrate entirely lacks distinguishing features close to the site of dehydrogenation. To identify the elusive mechanism underlying regioselectivity, we have determined two crystal structures of the archetypal Δ9 desaturase from castor in complex with acyl carrier protein (ACP), which show the bound ACP ideally situated to position C9 and C10 of the acyl chain adjacent to the diiron active site for Δ9 desaturation. Analysis of the structures and modeling of the complex between the highly homologous ivy Δ4 desaturase and ACP, identified a residue located at the entrance to the binding cavity, Asp280 in the castor desaturase (Lys275 in the ivy desaturase), which is strictly conserved within Δ9 and Δ4 enzymes but differs between them. We hypothesized that interaction between Lys275 and the phosphate of the pantetheine, seen in the ivy model, is key to positioning C4 and C5 adjacent to the diiron center for Δ4 desaturation. Mutating castor Asp280 to Lys resulted in a major shift from Δ9 to Δ4 desaturation. Thus, interaction between desaturase side-chain 280 and phospho-serine 38 of ACP, approximately 27 Å from the site of double-bond formation, predisposes ACP binding that favors either Δ9 or Δ4 desaturation via repulsion (acidic side chain) or attraction (positively charged side chain), respectively. Understanding the mechanism underlying remote control of regioselectivity provides the foundation for reengineering desaturase enzymes to create designer chemical feedstocks that would provide alternatives to those currently obtained from petrochemicals.

Fluidization of Membrane Lipids Enhances the Tolerance of Saccharomyces cerevisiae to Freezing and Salt Stress▿

PubMed Central

Rodríguez-Vargas, Sonia; Sánchez-García, Alicia; Martínez-Rivas, Jose Manuel; Prieto, Jose Antonio; Randez-Gil, Francisca

2007-01-01

Unsaturated fatty acids play an essential role in the biophysical characteristics of cell membranes and determine the proper function of membrane-attached proteins. Thus, the ability of cells to alter the degree of unsaturation in their membranes is an important factor in cellular acclimatization to environmental conditions. Many eukaryotic organisms can synthesize dienoic fatty acids, but Saccharomyces cerevisiae can introduce only a single double bond at the Δ9 position. We expressed two sunflower (Helianthus annuus) oleate Δ12 desaturases encoded by FAD2-1 and FAD2-3 in yeast cells of the wild-type W303-1A strain (trp1) and analyzed their effects on growth and stress tolerance. Production of the heterologous desaturases increased the content of dienoic fatty acids, especially 18:2Δ9,12, the unsaturation index, and the fluidity of the yeast membrane. The total fatty acid content remained constant, and the level of monounsaturated fatty acids decreased. Growth at 15°C was reduced in the FAD2 strains, probably due to tryptophan auxotrophy, since the trp1 (TRP1) transformants that produced the sunflower desaturases grew as well as the control strain did. Our results suggest that changes in the fluidity of the lipid bilayer affect tryptophan uptake and/or the correct targeting of tryptophan transporters. The expression of the sunflower desaturases, in either Trp+ or Trp− strains, increased NaCl tolerance. Production of dienoic fatty acids increased the tolerance to freezing of wild-type cells preincubated at 30°C or 15°C. Thus, membrane fluidity is an essential determinant of stress resistance in S. cerevisiae, and engineering of membrane lipids has the potential to be a useful tool of increasing the tolerance to freezing in industrial strains. PMID:17071783

Δ6-fatty acid desaturase and fatty acid elongase mRNA expression, phagocytic activity and weight-to-length relationships in channel catfish (Ictalurus punctatus) fed alternative diets with soy oil and a probiotic.

PubMed

Santerre, A; Téllez-Bañuelos, M C; Casas-Solís, J; Castro-Félix, P; Huízar-López, M R; Zaitseva, G P; Horta-Fernández, J L; Trujillo-García, E A; de la Mora-Sherer, D; Palafox-Luna, J A; Juárez-Carrillo, E

2015-09-22

A time-course feeding trial was conducted for 120 days on juvenile channel catfish (Ictalurus punctatus) to study the effects of diets differing in oil source (fish oil or soy oil) and supplementation with a commercial probiotic. Relative levels of Δ6-fatty acid desaturase (Δ6-FAD) and fatty acid elongase (FAE) expression were assessed in brain and liver tissues. Both genes showed similar expression levels in all groups studied. Fish weight-to-length relationships were evaluated using polynomial regression analyses, which identified a burst in weight and length in the channel catfish on day 105 of treatment; this increase was related to an increase in gene expression. Mid-intestinal lactic acid bacterium (LAB) count was determined according to morphological and biochemical criteria using API strips. There was no indication that intestinal LAB count was affected by the modified diets. The Cunningham glass adherence method was applied to evaluate phagocytic cell activity in peripheral blood. Reactive oxygen species (ROS) generation was assessed through the respiratory burst activity of spleen macrophages by the NBT reduction test. Probiotic-supplemented diets provided a good substrate for innate immune system function; the phagocytic index was significantly enhanced in fish fed soy oil and the probiotic, and at the end of the experimental period, ROS production increased in fish fed soy oil. The substitution of fish oil by soy oil is recommended for food formulation and will contribute to promoting sustainable aquaculture. Probiotics are also recommended for channel catfish farming as they may act as immunonutrients.

The Bacillus subtilis Acyl Lipid Desaturase Is a Δ5 Desaturase

PubMed Central

Altabe, Silvia G.; Aguilar, Pablo; Caballero, Gerardo M.; de Mendoza, Diego

2003-01-01

Bacillus subtilis was recently reported to synthesize unsaturated fatty acids (UFAs) with a double bond at positions Δ5, Δ7, and Δ9 (M. H. Weber, W. Klein, L. Muller, U. M. Niess, and M. A. Marahiel, Mol. Microbiol. 39:1321-1329, 2001). Since this finding would have considerable importance in the double-bond positional specificity displayed by the B. subtilis acyl lipid desaturase, we have attempted to confirm this observation. We report that the double bond of UFAs synthesized by B. subtilis is located exclusively at the Δ5 position, regardless of the growth temperature and the length chain of the fatty acids. PMID:12730185

An oleate 12-hydroxylase from Ricinus communis L. is a fatty acyl desaturase homolog

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van De Loo, F.J.; Broun, P.; Turner, S.

1995-07-18

Recent spectroscopic evidence implicating a binuclear iron site at the reaction center of fatty acyl desaturases suggested to us that certain fatty acyl hydroxylases may share significant amino acid sequence similarity with desaturases. To test this theory, we prepared a cDNA library from developing endosperm of the castor-oil plant (Ricinus communis L.) and obtained partial nucleotide sequences for 468 anonymous clones that were not expressed at high levels in leaves, a tissue deficient in 12-hydroxyoleic acid. This resulted in the identification of several cDNA clones encoding a polypeptide of 387 amino acids with a predicted molecular weight of 44,407 andmore » with {approx}67% sequence homology to microsomal oleate desaturase from Arabidopsis. Expression of a full-length clone under control of the cauliflower mosaic virus 35S promoter in transgenic tobacco resulted in the accumulation of low levels of 12-hydroxyoleic acid in seeds, indicating that the clone encodes the castor oleate hydroxylase. These results suggest that fatty acyl desaturases and hydroxylases share similar reaction mechanisms and provide an example of enzyme evolution. 26 refs., 6 figs., 1 tab.« less

A Bacillus subtilis Gene Induced by Cold Shock Encodes a Membrane Phospholipid Desaturase

PubMed Central

Aguilar, Pablo S.; Cronan, John E.; de Mendoza, Diego

1998-01-01

Bacillus subtilis grown at 37°C synthesizes saturated fatty acids with only traces of unsaturated fatty acids (UFAs). However, when cultures growing at 37°C are transferred to 20°C, UFA synthesis is induced. We report the identification and characterization of the gene encoding the fatty acid desaturase of B. subtilis. This gene, called des, was isolated by complementation of Escherichia coli strains with mutations in either of two different genes of UFA synthesis. The des gene encodes a polypeptide of 352 amino acid residues containing the three conserved histidine cluster motifs and two putative membrane-spanning domains characteristic of the membrane-bound desaturases of plants and cyanobacteria. Expression of the des gene in E. coli resulted in desaturation of palmitic acid moieties of the membrane phospholipids to give the novel mono-UFA cis-5-hexadecenoic acid, indicating that the B. subtilis des gene product is a Δ5 acyl-lipid desaturase. The des gene was disrupted, and the resulting null mutant strains were unable to synthesize UFAs upon a shift to low growth temperatures. The des null mutant strain grew as well as its congenic parent at 20 or 37°C but showed severely reduced survival during stationary phase. Analysis of operon fusions in which the des promoter directed the synthesis of a lacZ reporter gene showed that des expression is repressed at 37°C, but a shift of cultures from 37 to 20°C resulted in a 10- to 15-fold increase in transcription. This is the first report of a membrane phospholipid desaturase in a nonphotosynthetic organism and the first direct evidence for cold induction of a desaturase. PMID:9555904

Remote control of regioselectivity in acyl-acyl carrier protein-desaturases

PubMed Central

Guy, Jodie E.; Whittle, Edward; Moche, Martin; Lengqvist, Johan; Lindqvist, Ylva; Shanklin, John

2011-01-01

Regiospecific desaturation of long-chain saturated fatty acids has been described as approaching the limits of the discriminatory power of enzymes because the substrate entirely lacks distinguishing features close to the site of dehydrogenation. To identify the elusive mechanism underlying regioselectivity, we have determined two crystal structures of the archetypal Δ9 desaturase from castor in complex with acyl carrier protein (ACP), which show the bound ACP ideally situated to position C9 and C10 of the acyl chain adjacent to the diiron active site for Δ9 desaturation. Analysis of the structures and modeling of the complex between the highly homologous ivy Δ4 desaturase and ACP, identified a residue located at the entrance to the binding cavity, Asp280 in the castor desaturase (Lys275 in the ivy desaturase), which is strictly conserved within Δ9 and Δ4 enzymes but differs between them. We hypothesized that interaction between Lys275 and the phosphate of the pantetheine, seen in the ivy model, is key to positioning C4 and C5 adjacent to the diiron center for Δ4 desaturation. Mutating castor Asp280 to Lys resulted in a major shift from Δ9 to Δ4 desaturation. Thus, interaction between desaturase side-chain 280 and phospho-serine 38 of ACP, approximately 27 Å from the site of double-bond formation, predisposes ACP binding that favors either Δ9 or Δ4 desaturation via repulsion (acidic side chain) or attraction (positively charged side chain), respectively. Understanding the mechanism underlying remote control of regioselectivity provides the foundation for reengineering desaturase enzymes to create designer chemical feedstocks that would provide alternatives to those currently obtained from petrochemicals. PMID:21930947

Comparative Analysis and Distribution of Omega-3 lcPUFA Biosynthesis Genes in Marine Molluscs

PubMed Central

Surm, Joachim M.; Prentis, Peter J.; Pavasovic, Ana

2015-01-01

Recent research has identified marine molluscs as an excellent source of omega-3 long-chain polyunsaturated fatty acids (lcPUFAs), based on their potential for endogenous synthesis of lcPUFAs. In this study we generated a representative list of fatty acyl desaturase (Fad) and elongation of very long-chain fatty acid (Elovl) genes from major orders of Phylum Mollusca, through the interrogation of transcriptome and genome sequences, and various publicly available databases. We have identified novel and uncharacterised Fad and Elovl sequences in the following species: Anadara trapezia, Nerita albicilla, Nerita melanotragus, Crassostrea gigas, Lottia gigantea, Aplysia californica, Loligo pealeii and Chlamys farreri. Based on alignments of translated protein sequences of Fad and Elovl genes, the haeme binding motif and histidine boxes of Fad proteins, and the histidine box and seventeen important amino acids in Elovl proteins, were highly conserved. Phylogenetic analysis of aligned reference sequences was used to reconstruct the evolutionary relationships for Fad and Elovl genes separately. Multiple, well resolved clades for both the Fad and Elovl sequences were observed, suggesting that repeated rounds of gene duplication best explain the distribution of Fad and Elovl proteins across the major orders of molluscs. For Elovl sequences, one clade contained the functionally characterised Elovl5 proteins, while another clade contained proteins hypothesised to have Elovl4 function. Additional well resolved clades consisted only of uncharacterised Elovl sequences. One clade from the Fad phylogeny contained only uncharacterised proteins, while the other clade contained functionally characterised delta-5 desaturase proteins. The discovery of an uncharacterised Fad clade is particularly interesting as these divergent proteins may have novel functions. Overall, this paper presents a number of novel Fad and Elovl genes suggesting that many mollusc groups possess most of the

Decomposition of the fluorescence spectra of two FAD molecules in electron-transferring flavoprotein from Megasphaera elsdenii.

PubMed

Sato, Kyosuke; Nishina, Yasuzo; Shiga, Kiyoshi

2013-07-01

Electron-transferring flavoprotein (ETF) from Megasphaera elsdenii contains two FAD molecules, FAD-1 and FAD-2. FAD-2 shows an unusual absorption spectrum with a 400-nm peak. In contrast, ETFs from other sources such as pig contain one FAD and one AMP with the FAD showing a typical flavin absorption spectrum with 380- and 440-nm peaks. It is presumed that FAD-2 is the counterpart of the FAD in other ETFs. In this study, the FAD-1 and FAD-2 fluorescence spectra were determined by titration of FAD-1-bound ETF with FAD using excitation-emission matrix (EEM) fluorescence spectroscopy. The EEM data were globally analysed, and the FAD fluorescence spectra were calculated from the principal components using their respective absorption spectra. The FAD-2 fluorescence spectrum was different from that of pig ETF, which is more intense and blue-shifted. AMP-free pig ETF in acidic solution, which has a comparable absorption spectrum to FAD-2, also had a similar fluorescence spectrum. This result suggests that FAD-2 in M. elsdenii ETF and the FAD in acidic AMP-free pig ETF share a common microenvironment. A review of published ETF fluorescence spectra led to the speculation that the majority of ETF molecules in solution are in the conformation depicted by the crystal structure.

Fatty acid profiling of four different peanut Fatty Acid Desaturase (FAD) 2 genotypes at five seed development stages

USDA-ARS?s Scientific Manuscript database

Peanut is one of the most important edible oilseed crops. The level of oleic acid in peanut seeds can significantly affect the oil quality. Consuming peanut product from high oleic acid seeds may positively contribute to improving human health. The level of oleic acid in peanut seeds is mainly contr...

Identification of Shared and Unique Serum Lipid Profiles in Diabetes Mellitus and Myocardial Infarction.

PubMed

Kjellqvist, Sanela; Klose, Christian; Surma, Michal A; Hindy, George; Mollet, Inês G; Johansson, Anna; Chavaux, Patrick; Gottfries, Johan; Simons, Kai; Melander, Olle; Fernandez, Céline

2016-11-29

Diabetes mellitus (DM) and cardiovascular disease are associated with dyslipidemia, but the detailed lipid molecular pattern in both diseases remains unknown. We used shotgun mass spectrometry to determine serum levels of 255 molecular lipids in 316 controls, 171 DM, and 99 myocardial infarction (MI) events from a cohort derived from the Malmö Diet and Cancer study. Orthogonal projections to latent structures analyses were conducted between the lipids and clinical parameters describing DM or MI. Fatty acid desaturases (FADS) and elongation of very long chain fatty acid protein 5 (ELOVL5) activities were estimated by calculating product to precursor ratios of polyunsaturated fatty acids in complex lipids. FADS genotypes encoding these desaturases were then tested for association with lipid levels and ratios. Differences in the levels of lipids belonging to the phosphatidylcholine and triacylglyceride (TAG) classes contributed the most to separating DM from controls. TAGs also played a dominating role in discriminating MI from controls. Levels of C18:2 fatty acids in complex lipids were lower both in DM and MI versus controls (DM, P=0.004; MI, P=6.0E-06) at least due to an acceleration in the metabolic flux from C18:2 to C20:4 (eg, increased estimated ELOVL5: DM, P=0.02; MI, P=0.04, and combined elongase-desaturase activities: DM, P=3.0E-06; MI, P=2.0E-06). Minor allele carriers of FADS genotypes were associated with increased levels of C18:2 (P≤0.007) and lower desaturase activity (P≤0.002). We demonstrate a possible relationship between decreased levels of C18:2 in complex lipids and DM or MI. We thereby highlight the importance of molecular lipids in the pathogenesis of both diseases. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Evidence that norflurazon affects chloroplast lipid unsaturation in soybean leaves (Glycine max L.).

PubMed

Abrous-Belbachir, Ouzna; De Paepe, Rosine; Trémolières, Antoine; Mathieu, Chantal; Ad, Fatiha; Benhassaine-Kesri, Ghouziel

2009-12-09

Norflurazon is a bleaching herbicide known to block carotenoid biosynthesis by inhibiting phytoene desaturase activity. Soybean plants were treated with norflurazon, and we examined the effects on the desaturation of lipid molecular species in leaves using ammonium [1-(14)C] oleate labeling. In monogalactosyldiacylglycerol (MGDG), the main chloroplast lipid, a decrease in 18:3/18:3 molecular species and an increase in its precursors 18:2/18:3 and 18:2/18:2 were observed suggesting that the omega(3) FAD7 desaturase activity in planta was inhibited by norflurazon. The in vitro activity of MGDG synthase was also inhibited by 69%. In contrast, the amount of 18:3/18:3 molecular species of phosphatidylcholine (PC) in the extraplastid compartment increased. The observed increase in in vitro lysoPC-acyltransferase activity and activation of desaturation of [1-(14)C] oleate suggest that extraplastid omega(3)FAD3 desaturase was activated. Analysis of the expression of omega(3) FAD3 and omega(3) FAD7 genes in norflurazon treated plants indicate that omega(3) FAD7 and omega(3) FAD3 desaturases are controlled at the post-transcriptional level.

Identification and functional analysis of delta-9 desaturase, a key enzyme in PUFA Synthesis, isolated from the oleaginous diatom Fistulifera.

PubMed

Muto, Masaki; Kubota, Chihiro; Tanaka, Masayoshi; Satoh, Akira; Matsumoto, Mitsufumi; Yoshino, Tomoko; Tanaka, Tsuyoshi

2013-01-01

Oleaginous microalgae are one of the promising resource of nonedible biodiesel fuel (BDF) feed stock alternatives. Now a challenge task is the decrease of the long-chain polyunsaturated fatty acids (PUFAs) content affecting on the BDF oxidative stability by using gene manipulation techniques. However, only the limited knowledge has been available concerning the fatty acid and PUFA synthesis pathways in microalgae. Especially, the function of Δ9 desaturase, which is a key enzyme in PUFA synthesis pathway, has not been determined in diatom. In this study, 4 Δ(9) desaturase genes (fD9desA, fD9desB, fD9desC and fD9desD) from the oleaginous diatom Fistulifera were newly isolated and functionally characterized. The putative Δ(9) acyl-CoA desaturases in the endoplasmic reticulum (ER) showed 3 histidine clusters that are well-conserved motifs in the typical Δ(9) desaturase. Furthermore, the function of these Δ(9) desaturases was confirmed in the Saccharomyces cerevisiae ole1 gene deletion mutant (Δole1). All the putative Δ(9) acyl-CoA desaturases showed Δ(9) desaturation activity for C16∶0 fatty acids; fD9desA and fD9desB also showed desaturation activity for C18∶0 fatty acids. This study represents the first functional analysis of Δ(9) desaturases from oleaginous microalgae and from diatoms as the first enzyme to introduce a double bond in saturated fatty acids during PUFA synthesis. The findings will provide beneficial insights into applying metabolic engineering processes to suppressing PUFA synthesis in this oleaginous microalgal strain.

Mutations in a delta9-Stearoyl-ACP-Desaturase Gene Are Associated with Enhanced Stearic Acid Levels in Soybean Seeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, P.; Shanklin, J.; Burton, J. W.

2008-11-01

Stearic acid (18:0) is typically a minor component of soybean [Glycine max (L.) Merr.] oil, accounting for only 2 to 4% of the total fatty acid content. Increasing stearic acid levels of soybean oil would lead to enhanced oxidative stability, potentially reducing the need for hydrogenation, a process leading to the formation of undesirable trans fatty acids. Although mutagenesis strategies have been successful in developing soybean germplasm with elevated 18:0 levels in the seed oil, the specific gene mutations responsible for this phenotype were not known. We report a newly identified soybean gene, designated SACPD-C, that encodes a unique isoformmore » of {Delta}{sup 9}-stearoyl-ACP-desaturase, the enzyme responsible for converting stearic acid to oleic acid (18:1). High levels of SACPD-C transcript were only detected in developing seed tissue, suggesting that the encoded desaturase functions to enhance oleic acid biosynthetic capacity as the immature seed is actively engaged in triacylglycerol production and storage. The participation of SACPD-C in storage triacylglycerol synthesis is further supported by the observation of mutations in this gene in two independent sources of elevated 18:0 soybean germplasm, A6 (30% 18:0) and FAM94-41 (9% 18:0). A molecular marker diagnostic for the FAM94-41 SACPD-C gene mutation strictly associates with the elevated 18:0 phenotype in a segregating population, and could thus serve as a useful tool in the development of cultivars with oils possessing enhanced oxidative stability.« less

Genetic loci associated with plasma phospholipid n-3 fatty acids: a meta-analysis of genome-wide association studies from the CHARGE Consortium.

PubMed

Lemaitre, Rozenn N; Tanaka, Toshiko; Tang, Weihong; Manichaikul, Ani; Foy, Millennia; Kabagambe, Edmond K; Nettleton, Jennifer A; King, Irena B; Weng, Lu-Chen; Bhattacharya, Sayanti; Bandinelli, Stefania; Bis, Joshua C; Rich, Stephen S; Jacobs, David R; Cherubini, Antonio; McKnight, Barbara; Liang, Shuang; Gu, Xiangjun; Rice, Kenneth; Laurie, Cathy C; Lumley, Thomas; Browning, Brian L; Psaty, Bruce M; Chen, Yii-Der I; Friedlander, Yechiel; Djousse, Luc; Wu, Jason H Y; Siscovick, David S; Uitterlinden, André G; Arnett, Donna K; Ferrucci, Luigi; Fornage, Myriam; Tsai, Michael Y; Mozaffarian, Dariush; Steffen, Lyn M

2011-07-01

Long-chain n-3 polyunsaturated fatty acids (PUFAs) can derive from diet or from α-linolenic acid (ALA) by elongation and desaturation. We investigated the association of common genetic variation with plasma phospholipid levels of the four major n-3 PUFAs by performing genome-wide association studies in five population-based cohorts comprising 8,866 subjects of European ancestry. Minor alleles of SNPs in FADS1 and FADS2 (desaturases) were associated with higher levels of ALA (p = 3 x 10⁻⁶⁴) and lower levels of eicosapentaenoic acid (EPA, p = 5 x 10⁻⁵⁸) and docosapentaenoic acid (DPA, p = 4 x 10⁻¹⁵⁴). Minor alleles of SNPs in ELOVL2 (elongase) were associated with higher EPA (p = 2 x 10⁻¹²) and DPA (p = 1 x 10⁻⁴³) and lower docosahexaenoic acid (DHA, p = 1 x 10⁻¹⁵). In addition to genes in the n-3 pathway, we identified a novel association of DPA with several SNPs in GCKR (glucokinase regulator, p = 1 x 10⁻⁸). We observed a weaker association between ALA and EPA among carriers of the minor allele of a representative SNP in FADS2 (rs1535), suggesting a lower rate of ALA-to-EPA conversion in these subjects. In samples of African, Chinese, and Hispanic ancestry, associations of n-3 PUFAs were similar with a representative SNP in FADS1 but less consistent with a representative SNP in ELOVL2. Our findings show that common variation in n-3 metabolic pathway genes and in GCKR influences plasma phospholipid levels of n-3 PUFAs in populations of European ancestry and, for FADS1, in other ancestries.

Genetic Loci Associated with Plasma Phospholipid n-3 Fatty Acids: A Meta-Analysis of Genome-Wide Association Studies from the CHARGE Consortium

PubMed Central

Kabagambe, Edmond K.; Nettleton, Jennifer A.; King, Irena B.; Weng, Lu-Chen; Bhattacharya, Sayanti; Bandinelli, Stefania; Bis, Joshua C.; Rich, Stephen S.; Jacobs, David R.; Cherubini, Antonio; McKnight, Barbara; Liang, Shuang; Gu, Xiangjun; Rice, Kenneth; Laurie, Cathy C.; Lumley, Thomas; Browning, Brian L.; Psaty, Bruce M.; Chen, Yii-Der I.; Friedlander, Yechiel; Djousse, Luc; Wu, Jason H. Y.; Siscovick, David S.; Uitterlinden, André G.; Arnett, Donna K.; Ferrucci, Luigi; Fornage, Myriam; Tsai, Michael Y.; Mozaffarian, Dariush; Steffen, Lyn M.

2011-01-01

Long-chain n-3 polyunsaturated fatty acids (PUFAs) can derive from diet or from α-linolenic acid (ALA) by elongation and desaturation. We investigated the association of common genetic variation with plasma phospholipid levels of the four major n-3 PUFAs by performing genome-wide association studies in five population-based cohorts comprising 8,866 subjects of European ancestry. Minor alleles of SNPs in FADS1 and FADS2 (desaturases) were associated with higher levels of ALA (p = 3×10−64) and lower levels of eicosapentaenoic acid (EPA, p = 5×10−58) and docosapentaenoic acid (DPA, p = 4×10−154). Minor alleles of SNPs in ELOVL2 (elongase) were associated with higher EPA (p = 2×10−12) and DPA (p = 1×10−43) and lower docosahexaenoic acid (DHA, p = 1×10−15). In addition to genes in the n-3 pathway, we identified a novel association of DPA with several SNPs in GCKR (glucokinase regulator, p = 1×10−8). We observed a weaker association between ALA and EPA among carriers of the minor allele of a representative SNP in FADS2 (rs1535), suggesting a lower rate of ALA-to-EPA conversion in these subjects. In samples of African, Chinese, and Hispanic ancestry, associations of n-3 PUFAs were similar with a representative SNP in FADS1 but less consistent with a representative SNP in ELOVL2. Our findings show that common variation in n-3 metabolic pathway genes and in GCKR influences plasma phospholipid levels of n-3 PUFAs in populations of European ancestry and, for FADS1, in other ancestries. PMID:21829377

Cloning and characterization of a delta-6 desaturase encoding gene from Nannochloropsis oculata

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Yu, Jianzhong; Zhu, Baohua; Pan, Kehou; Pan, Jin; Yang, Guanpin

2011-03-01

A gene ( NANOC-D6D) encoding a desaturase that removes two hydrogen atoms from fatty acids at delta 6 position was isolated from a cDNA library of Nannochloropsis oculata (Droop) D. J. Hibberd (Eustigmatophyceae). The unicellular marine microalga N. oculata synthesizes rich long chain polyunsaturated fatty acids (LCPUFAs), including eicosapentaenoic acid (20:5n-3, EPA). The deduced protein contains 474 amino acids that fold into 4 trans-membrane domains. The neighbor-joining phylogenetic tree indicates that NANOC-D6D is phylogenetically close to the delta-6 fatty acid desaturase of marine microalgae such as Glossomastix chrysoplasta, Thalassiosira pseudonana, and Phaeodactylum tricornutum. The gene was expressed in Saccharomyces cerevisiae INVScl to verify the substrate specificity of NANOC-D6D. Our results suggest that the recombinant NANOC-D6D simultaneously desaturates linoleic acid (LA) and α-linolenic acid (ALA).

Induction of 1-acylglycerophosphocholine acyltransferase genes by fibrates in the liver of rats.

PubMed

Yamazaki, Tohru; Wakabayashi, Michiko; Ikeda, Erika; Tanaka, Shizuyo; Sakamoto, Takeshi; Mitsumoto, Atsushi; Kudo, Naomi; Kawashima, Yoichi

2012-01-01

The effect of fibrates (clofibric acid, bezafibrate and fenofibrate) on the gene expression and activity of 1-acylglycerophosphocholine acyltransferase (LPCAT) was investigated. The administration of 0.1% (w/w) clofibric acid, bezafibrate or fenofibrate in diet for 14 d to rats induced LPCAT activity in hepatic microsomes in the following order: fenofibrate>bezafibrate>clofibric acid. The LPCAT induced by fenofibrate preferred to arachidonoyl-CoA and linoleoyl-CoA to a greater extent than did LPCAT in control microsomes. The treatment with the fibrates resulted in upregulation of the relative expression of mRNAs encoding LPCAT3 and LPCAT4 in the following order: fenofibrate>bezafibrate>clofibric acid. The administration of fibrates did not change the expression of genes encoding either LPCAT1 or LPCAT2. The treatment with fibrates elevated relative levels of both mRNAs encoding Δ6 desaturase (Fads2) and Δ5 desaturase (Fads1) in the order of fenofibrate>bezafibrate>clofibric acid, and the extent of the increase in the level of Δ6 desaturase mRNA was greater than that of Δ5 desaturase. Fatty acid profile in hepatic phosphatidylcholine (PC) was significantly changed by the treatments with fibrates. These results suggest (i) that fibrates induce LPCAT activity in hepatic microsomes by elevating the expression of genes encoding LPCAT3 and LPCAT4, (ii) that the changes in fatty acid profile of hepatic PC are, in part, due to the elevated expression of two isoforms, LPCAT3 and LPCAT4, and (iii) that the ability of fibrates to induce these changes are in the order of fenofibrate>bezafibrate>clofibric acid.

Phytoene Desaturase from Oryza sativa: Oligomeric Assembly, Membrane Association and Preliminary 3D-Analysis

PubMed Central

Koschmieder, Julian; Brausemann, Anton; Drepper, Friedel; Rodriguez-Franco, Marta; Ghisla, Sandro; Warscheid, Bettina; Einsle, Oliver; Beyer, Peter

2015-01-01

Recombinant phytoene desaturase (PDS-His6) from rice was purified to near-homogeneity and shown to be enzymatically active in a biphasic, liposome-based assay system. The protein contains FAD as the sole protein-bound redox-cofactor. Benzoquinones, not replaceable by molecular oxygen, serve as a final electron acceptor defining PDS as a 15-cis-phytoene (donor):plastoquinone oxidoreductase. The herbicidal PDS-inhibitor norflurazon is capable of arresting the reaction by stabilizing the intermediary FADred, while an excess of the quinone acceptor relieves this blockage, indicating competition. The enzyme requires its homo-oligomeric association for activity. The sum of data collected through gel permeation chromatography, non-denaturing polyacrylamide electrophoresis, chemical cross-linking, mass spectrometry and electron microscopy techniques indicate that the high-order oligomers formed in solution are the basis for an active preparation. Of these, a tetramer consisting of dimers represents the active unit. This is corroborated by our preliminary X-ray structural analysis that also revealed similarities of the protein fold with the sequence-inhomologous bacterial phytoene desaturase CRTI and other oxidoreductases of the GR2-family of flavoproteins. This points to an evolutionary relatedness of CRTI and PDS yielding different carotene desaturation sequences based on homologous protein folds. PMID:26147209

Polyploid genome of Camelina sativa revealed by isolation of fatty acid synthesis genes

PubMed Central

2010-01-01

Background Camelina sativa, an oilseed crop in the Brassicaceae family, has inspired renewed interest due to its potential for biofuels applications. Little is understood of the nature of the C. sativa genome, however. A study was undertaken to characterize two genes in the fatty acid biosynthesis pathway, fatty acid desaturase (FAD) 2 and fatty acid elongase (FAE) 1, which revealed unexpected complexity in the C. sativa genome. Results In C. sativa, Southern analysis indicates the presence of three copies of both FAD2 and FAE1 as well as LFY, a known single copy gene in other species. All three copies of both CsFAD2 and CsFAE1 are expressed in developing seeds, and sequence alignments show that previously described conserved sites are present, suggesting that all three copies of both genes could be functional. The regions downstream of CsFAD2 and upstream of CsFAE1 demonstrate co-linearity with the Arabidopsis genome. In addition, three expressed haplotypes were observed for six predicted single-copy genes in 454 sequencing analysis and results from flow cytometry indicate that the DNA content of C. sativa is approximately three-fold that of diploid Camelina relatives. Phylogenetic analyses further support a history of duplication and indicate that C. sativa and C. microcarpa might share a parental genome. Conclusions There is compelling evidence for triplication of the C. sativa genome, including a larger chromosome number and three-fold larger measured genome size than other Camelina relatives, three isolated copies of FAD2, FAE1, and the KCS17-FAE1 intergenic region, and three expressed haplotypes observed for six predicted single-copy genes. Based on these results, we propose that C. sativa be considered an allohexaploid. The characterization of fatty acid synthesis pathway genes will allow for the future manipulation of oil composition of this emerging biofuel crop; however, targeted manipulations of oil composition and general development of C. sativa should

Menhaden oil, but not safflower or soybean oil, aids in restoring the polyunsaturated fatty acid profile in the novel delta-6-desaturase null mouse

PubMed Central

2012-01-01

Background Polyunsaturated fatty acids (PUFA) have diverse biological effects, from promoting inflammation to preventing cancer and heart disease. Growing evidence suggests that individual PUFA may have independent effects in health and disease. The individual roles of the two essential PUFA, linoleic acid (LA) and α-linolenic acid (ALA), have been difficult to discern from the actions of their highly unsaturated fatty acid (HUFA) downstream metabolites. This issue has recently been addressed through the development of the Δ-6 desaturase knock out (D6KO) mouse, which lacks the rate limiting Δ-6 desaturase enzyme and therefore cannot metabolize LA or ALA. However, a potential confounder in this model is the production of novel Δ-5 desaturase (D5D) derived fatty acids when D6KO mice are fed diets containing LA and ALA, but void of arachidonic acid. Objective The aim of the present study was to characterize how the D6KO model differentially responds to diets containing the essential n-6 and n-3 PUFA, and whether the direct provision of downstream HUFA can rescue the phenotype and prevent the production of D5D fatty acids. Methodology Liver and serum phospholipid (PL) fatty acid composition was examined in D6KO and wild type mice fed i) 10% safflower oil diet (SF, LA rich) ii) 10% soy diet (SO, LA+ALA) or iii) 3% menhaden oil +7% SF diet (MD, HUFA rich) for 28 days (n = 3-7/group). Results Novel D5D fatty acids were found in liver PL of D6KO fed SF or SO-fed mice, but differed in the type of D5D fatty acid depending on diet. Conversely, MD-fed D6KO mice had a liver PL fatty acid profile similar to wild-type mice. Conclusions Through careful consideration of the dietary fatty acid composition, and especially the HUFA content in order to prevent the synthesis of D5D fatty acids, the D6KO model has the potential to elucidate the independent biological and health effects of the parent n-6 and n-3 fatty acids, LA and ALA. PMID:22642787

An N-terminal di-proline motif is essential for fatty acid–dependent degradation of Δ9-desaturase in Drosophila

PubMed Central

Murakami, Akira; Nagao, Kohjiro; Juni, Naoto; Hara, Yuji; Umeda, Masato

2017-01-01

The Δ9-fatty acid desaturase introduces a double bond at the Δ9 position of the acyl moiety of acyl-CoA and regulates the cellular levels of unsaturated fatty acids. However, it is unclear how Δ9-desaturase expression is regulated in response to changes in the levels of fatty acid desaturation. In this study, we found that the degradation of DESAT1, the sole Δ9-desaturase in the Drosophila cell line S2, was significantly enhanced when the amounts of unsaturated acyl chains of membrane phospholipids were increased by supplementation with unsaturated fatty acids, such as oleic and linoleic acids. In contrast, inhibition of DESAT1 activity remarkably suppressed its degradation. Of note, removal of the DESAT1 N-terminal domain abolished the responsiveness of DESAT1 degradation to the level of fatty acid unsaturation. Further truncation and amino acid replacement analyses revealed that two sequential prolines, the second and third residues of DESAT1, were responsible for the unsaturated fatty acid–dependent degradation. Although degradation of mouse stearoyl-CoA desaturase 1 (SCD1) was unaffected by changes in fatty acid unsaturation, introduction of the N-terminal sequential proline residues into SCD1 conferred responsiveness to unsaturated fatty acid–dependent degradation. Furthermore, we also found that the Ca2+-dependent cysteine protease calpain is involved in the sequential proline–dependent degradation of DESAT1. In light of these findings, we designated the sequential prolines at the second and third positions of DESAT1 as a “di-proline motif,” which plays a crucial role in the regulation of Δ9-desaturase expression in response to changes in the level of cellular unsaturated fatty acids. PMID:28972163

ω-3 Long-Chain Polyunsaturated Fatty Acids and Fatty Acid Desaturase Activity Ratios as Eventual Endophenotypes for ADHD.

PubMed

Henríquez-Henríquez, Marcela; Solari, Sandra; Várgas, Gisela; Vásquez, Luis; Allende, Fidel; Castañón S, Carla; Tenorio, Marcela; Quiroga Gutiérrez, Teresa

2015-11-01

Epidemiological studies suggest that long-chain polyunsaturated fatty acids (LC-PUFAs) may be suitable as endophenotypes for ADHD. To be appropriated vulnerability traits, endophenotypes should be altered in unaffected relatives of index cases. Serum profiles of LC-PUFAs in unaffected relatives of ADHD patients remain understudied. The main objective of this study was to compare serum LC-PUFAs in ADHD patients, unaffected relatives of index cases, and general-population unaffected participants. LC-PUFA profiles of 72 participants (27 ADHD patients, 27 unaffected relatives, and 18 general-population participants) were obtained by gas chromatography-mass spectrometry (GC-MS). Groups were compared by parametrical statistics. Unaffected females from the general population presented lower Docosapentaenoic acid (DPA; p = .0012) and a-linolenic acid (ALA; p = .0091) levels compared with ADHD females and unaffected relatives. In addition, docosahexaenoic acid (DHA)/ALA and DHA/DPA ratios, addressing desaturase activity, were significantly lower in ADHD patients and unaffected relatives of ADHD patients in the female-subgroup (p = .022 and .04, respectively). DHA/ALA, DHA/DPA, serum DPA, and serum ALA may be suitable as endophenotypes for ADHD women. © The Author(s) 2012.

Plasma fatty acid composition, estimated desaturase activities, and their relation with the metabolic syndrome in a population at high risk of cardiovascular disease.

PubMed

Mayneris-Perxachs, Jordi; Guerendiain, Marcela; Castellote, Ana I; Estruch, Ramón; Covas, María Isabel; Fitó, Montserrat; Salas-Salvadó, Jordi; Martínez-González, Miguel A; Aros, Fernando; Lamuela-Raventós, Rosa M; López-Sabater, M Carmen

2014-02-01

The metabolic syndrome (MetS) is a clustering of various metabolic abnormalities which is associated with increased risk of cardiovascular disease (CVD) and type 2 diabetes mellitus. Due to its increasing prevalence, it has become an important public health concern. Altered fatty acid (FA) composition and desaturase activities have been associated with several metabolic diseases, including MetS. The aim of the present study was to evaluate the relationship of the plasma FA profile and desaturase activities with the MetS in a Mediterranean population at high risk of CVD. Baseline data from 427 participants aged 55-80 years who took part in the interventional PREDIMED study were obtained. Individual FA was determined in plasma and desaturase activities were estimated from product/precursor ratios. Odds ratios (OR) and partial correlation coefficients were used to examine these relations with MetS and its components, respectively. We found higher levels of C14:0, C16:0, C16:1n-7, estimated Δ(9)- or stearoyl-CoA desaturase (SCD), and estimated Δ(6) desaturase (D6D), and lower levels of C18:2n-6 in people with MetS compared to those without it. After adjustment for several confounders, only higher quartiles of C14:0, C16:0, C16:1n-7, and D6D were found to be associated with an increasing prevalence of MetS, while higher quartiles of C18:2n-6 were inversely associated with MetS. High proportions of C14:0, C16:0, C16:1n-7, C20:3n-6, SCD, and D6D, and decreased proportions of C18:2n-6 and estimated Δ(5)-desaturase (D5D) were associated with adverse profiles of several metabolic risk factors. Women showed more unhealthy FA pattern and lipid profiles than men, but only among those with MetS. A FA composition and estimated desaturase activities consisting in high levels of SFA, SCD and D6D, and low levels of PUFA and D5D are associated with increased MetS probability and are characteristic of people presenting MetS, especially women. These findings support those observed

Factors affecting the palmitoyl-coenzyme A desaturase of Saccharomyces cerevisiae

NASA Technical Reports Server (NTRS)

Klein, H. P.; Volkmann, C. M.

1975-01-01

The activity and stability of the palmitoyl-coenzyme A (CoA) desaturase complex of Saccharomyces cerevisiae was influenced by several factors. Cells, grown nonaerobically and then incubated with glucose, either in air or under N2, showed a marked increase in desaturase activity. Cycloheximide, added during such incubations, prevented the increase in activity, suggesting de novo synthesis. The stability of the desaturase from cells grown nonaerobically was affected by subsequent treatment of the cells; enzyme from freshly harvested cells, or from cells that were then shaken under nitrogen, readily lost activity upon washing or during density gradient analysis, whereas aerated cells, in the presence or absence of glucose, yielded stable enzyme preparations. The loss of activity in nonaerobic preparations could be reversed by adding soluble supernatant from these homogenates and could be prevented by growing the cells in the presence of palmitoleic acid and ergosterol, but not with several other lipids tested.

A single nucleotide polymorphism in the FADS1/FADS2 gene is associated with plasma lipid profiles in two genetically similar Asian ethnic groups with distinctive differences in lifestyle.

PubMed

Nakayama, Kazuhiro; Bayasgalan, Tumenbayer; Tazoe, Fumiko; Yanagisawa, Yoshiko; Gotoh, Takaya; Yamanaka, Kazuhiro; Ogawa, Ayumi; Munkhtulga, Lkhagvasuren; Chimedregze, Ulziiburen; Kagawa, Yasuo; Ishibashi, Shun; Iwamoto, Sadahiko

2010-06-01

Recent genome-wide association studies (GWASs) showed that single nucleotide polymorphisms (SNPs) in FADS1/FADS2 were associated with plasma lipid concentrations in populations with European ancestry. We investigated the associations between the SNPs in FADS1/FADS2 and plasma concentrations of triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in two Asian groups, i.e., Japanese and Mongolians. The genotype of rs174547 (T/C), found to be associated with triglyceride and HDL-C concentrations in the GWAS, was determined in 21,004 Japanese and 1,203 Mongolian individuals. Genotype-phenotype association was assessed by using multiple linear regression models, assuming an additive model of inheritance. The copy number of the rs174547 C allele was significantly associated with increased triglyceride levels (P = 1.5 x 10(-6)) and decreased HDL-C levels (P = 0.03) in the Japanese population. On the other hand, in the Mongolian population, the rs174547 C allele copy number was strongly associated with decreased LDL-C levels (P = 2.6 x 10(-6)), but was not associated with triglyceride and HDL-C levels. The linkage disequilibrium pattern and haplotype structures of SNPs around the FADS1/FADS2 locus showed no marked dissimilarity between Japanese and Mongolian individuals. The present data indicate that the FADS1/FADS2 locus can be added to the growing list of loci involved in polygenic dyslipidemia in Asians. Furthermore, the variable effects of FADS1/FADS2 on plasma lipid profiles in Asians may result from differences in the dietary intake of polyunsaturated fatty acids, which serve as substrates for enzymes encoded by FADS1/FADS2.

Effect of tanniniferous Terminalia chebula extract on rumen biohydrogenation, ∆(9)-desaturase activity, CLA content and fatty acid composition in longissimus dorsi muscle of kids.

PubMed

Rana, Madhu Suman; Tyagi, A; Hossain, Sk Asraf; Tyagi, A K

2012-03-01

Conjugated linoleic acid, a fatty acid found in milk fat and ruminant meat is one of the functional food components. Modifying fatty acid composition so as to increase CLA and other beneficial PUFA/MUFA level and reducing SFA levels might be a key to enhance the neutraceutical and therapeutic value of ruminant-derived food products. In the present experiment, the effect of supplementation of polyphenol rich Terminalia chebula plant extract at different concentrations (1.06g/kg and 3.18g/kg of body weight in T1 and T2 groups, respectively) was investigated on fatty acid composition of rumen fluid, plasma, intramuscular fat and Δ9-desaturase activity in longissimus dorsi muscle of crossbred kids. Total MUFA and PUFA content in muscle were enhanced by 25 and 35%, respectively, whereas SFA was reduced by 20% thereby improving the desaturation index. Δ9-desaturase activity also increased by 47% resulting in an enhancement of total CLA content (58.73%) in muscle. Copyright © 2011 Elsevier Ltd. All rights reserved.

In vitro synthesis of 9,10-dihydroxyhexadecanoic acid using recombinant Escherichia coli.

PubMed

Kaprakkaden, Anees; Srivastava, Preeti; Bisaria, Virendra Swarup

2017-05-18

Hydroxy fatty acids are widely used in food, chemical and cosmetic industries. A variety of dihydroxy fatty acids have been synthesized so far; however, no studies have been done on the synthesis of 9,10-dihydroxyhexadecanoic acid. In the present study recombinant E. coli has been used for the heterologous expression of fatty acid hydroxylating enzymes and the whole cell lysate of the induced culture was used for in vitro production of 9,10-dihydroxyhexadecanoic acid. A first of its kind proof of principle has been successfully demonstrated for the production of 9,10-dihydroxyhexadecanoic acid using three different enzymes viz. fatty acid desaturase (FAD) from Saccharomyces cerevisiae, epoxide hydrolase (EH) from Caenorhabditis elegance and epoxygenase (EPOX) from Stokasia laevis. The genes for these proteins were codon-optimised, synthesised and cloned in pET 28a (+) vector. The culture conditions for induction of these three proteins in E. coli were optimised in shake flask. The induced cell lysates were used both singly and in combination along with the trans-supply of hexadecanoic acid and 9-hexadecenoic acid, followed by product profiling by GC-MS. Formation of 9,10-dihydroxyhexadecanoic acid was successfully achieved when combination of induced cell lysates of recombinant E. coli containing FAD, EH, and EPOX were incubated with 9-hexadecenoic acid. The in vitro production of 9,10-dihydroxyhexadecanoic acid synthesis using three fatty acid modification genes from different sources has been successfully demonstrated. The strategy adopted can be used for the production of similar compounds.

A single mutation in the castor Delta9-18:0-desaturase changes reaction partitioning from desaturation to oxidase chemistry.

PubMed

Guy, Jodie E; Abreu, Isabel A; Moche, Martin; Lindqvist, Ylva; Whittle, Edward; Shanklin, John

2006-11-14

Sequence analysis of the diiron cluster-containing soluble desaturases suggests they are unrelated to other diiron enzymes; however, structural alignment of the core four-helix bundle of desaturases to other diiron enzymes reveals a conserved iron binding motif with similar spacing in all enzymes of this structural class, implying a common evolutionary ancestry. Detailed structural comparison of the castor desaturase with that of a peroxidase, rubrerythrin, shows remarkable conservation of both identity and geometry of residues surrounding the diiron center, with the exception of residue 199. Position 199 is occupied by a threonine in the castor desaturase, but the equivalent position in rubrerythrin contains a glutamic acid. We previously hypothesized that a carboxylate in this location facilitates oxidase chemistry in rubrerythrin by the close apposition of a residue capable of facilitating proton transfer to the activated oxygen (in a hydrophobic cavity adjacent to the diiron center based on the crystal structure of the oxygen-binding mimic azide). Here we report that desaturase mutant T199D binds substrate but its desaturase activity decreases by approximately 2 x 10(3)-fold. However, it shows a >31-fold increase in peroxide-dependent oxidase activity with respect to WT desaturase, as monitored by single-turnover stopped-flow spectrometry. A 2.65-A crystal structure of T199D reveals active-site geometry remarkably similar to that of rubrerythrin, consistent with its enhanced function as an oxidase enzyme. That a single amino acid substitution can switch reactivity from desaturation to oxidation provides experimental support for the hypothesis that the desaturase evolved from an ancestral oxidase enzyme.

A single mutation in the castor Δ9-18:0-desaturase changes reaction partitioning from desaturation to oxidase chemistry

PubMed Central

Guy, Jodie E.; Abreu, Isabel A.; Moche, Martin; Lindqvist, Ylva; Whittle, Edward; Shanklin, John

2006-01-01

Sequence analysis of the diiron cluster-containing soluble desaturases suggests they are unrelated to other diiron enzymes; however, structural alignment of the core four-helix bundle of desaturases to other diiron enzymes reveals a conserved iron binding motif with similar spacing in all enzymes of this structural class, implying a common evolutionary ancestry. Detailed structural comparison of the castor desaturase with that of a peroxidase, rubrerythrin, shows remarkable conservation of both identity and geometry of residues surrounding the diiron center, with the exception of residue 199. Position 199 is occupied by a threonine in the castor desaturase, but the equivalent position in rubrerythrin contains a glutamic acid. We previously hypothesized that a carboxylate in this location facilitates oxidase chemistry in rubrerythrin by the close apposition of a residue capable of facilitating proton transfer to the activated oxygen (in a hydrophobic cavity adjacent to the diiron center based on the crystal structure of the oxygen-binding mimic azide). Here we report that desaturase mutant T199D binds substrate but its desaturase activity decreases by ≈2 × 103-fold. However, it shows a >31-fold increase in peroxide-dependent oxidase activity with respect to WT desaturase, as monitored by single-turnover stopped-flow spectrometry. A 2.65-Å crystal structure of T199D reveals active-site geometry remarkably similar to that of rubrerythrin, consistent with its enhanced function as an oxidase enzyme. That a single amino acid substitution can switch reactivity from desaturation to oxidation provides experimental support for the hypothesis that the desaturase evolved from an ancestral oxidase enzyme. PMID:17088542

Omega-6 polyunsaturated fatty acids, serum zinc, delta-5- and delta-6-desaturase activities and incident metabolic syndrome.

PubMed

Yary, T; Voutilainen, S; Tuomainen, T-P; Ruusunen, A; Nurmi, T; Virtanen, J K

2017-08-01

The associations of n-6 polyunsaturated fatty acids (PUFA) with metabolic syndrome have been poorly explored. We investigated the associations of the serum n-6 PUFA and the activities of enzymes involved in the PUFA metabolism, delta-5-desaturase (D5D) and delta-6-desaturase (D6D) with risk of incident metabolic syndrome. We also investigated whether zinc, a cofactor for these enzymes, modifies these associations. A prospective follow-up study was conducted on 661 men who were aged 42-60 years old at baseline in 1984-1989 and who were re-examined in 1998-2001. Men in the highest versus the lowest serum total omega-6 PUFA tertile had a 70% lower multivariate-adjusted risk of incident metabolic syndrome [odds ratio (OR) = 0.30; 95% confidence interval (CI) = 0.18-0.51, P trend < 0.001]. Inverse associations were also observed for linoleic acid, arachidonic acid and D5D activity. By contrast, men in the highest tertile of D6D activity had an 84% higher risk (OR = 1.84; 95% CI = 1.15-2.94, P trend = 0.008). Similar associations were observed with many of the metabolic syndrome components at the re-examinations. Most associations were attenuated after adjustment for body mass index. Finally, the associations of D6D and LA were stronger among those with a higher serum zinc concentration. Higher serum total n-6 PUFA, linoleic acid and arachidonic acid concentrations and D5D activity were associated with a lower risk of developing metabolic syndrome and higher D6D activity was associated with a higher risk. The role of zinc also needs to be investigated in other populations. © 2016 The British Dietetic Association Ltd.

Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alloatti, Andres; Gupta, Shreedhara; Gualdron-Lopez, Melisa

2011-08-26

Highlights: {yields} Inhibiting {Delta}9 desaturase drastically changes T. brucei's fatty-acid composition. {yields} Isoxyl specifically inhibits the {Delta}9 desaturase causing a growth arrest. {yields} RNA interference of desaturase expression causes a similar effect. {yields} Feeding T. brucei-infected mice with Isoxyl decreases the parasitemia. {yields} 70% of Isoxyl-treated mice survived the trypanosome infection. -- Abstract: Trypanosoma brucei, the etiologic agent of sleeping sickness, is exposed to important changes in nutrients and temperature during its life cycle. To adapt to these changes, the fluidity of its membranes plays a crucial role. This fluidity, mediated by the fatty-acid composition, is regulated by enzymes namedmore » desaturases. We have previously shown that the oleoyl desaturase is essential for Trypanosoma cruzi and T. brucei. In this work, we present experimental support for the relevance of stearoyl-CoA desaturase (SCD) for T. brucei's survival, in both its insect or procyclic-form (PCF) and bloodstream-form (BSF) stages. We evaluated this essentiality in two different ways: by generating a SCD knocked-down parasite line using RNA interference, and by chemical inhibition of the enzyme with two compounds, Isoxyl and a thiastearate with the sulfur atom at position 10 (10-TS). The effective concentration for 50% growth inhibition (EC{sub 50}) of PCF was 1.0 {+-} 0.2 {mu}M for Isoxyl and 5 {+-} 2 {mu}M for 10-TS, whereas BSF appeared more susceptible with EC{sub 50} values 0.10 {+-} 0.03 {mu}M (Isoxyl) and 1.0 {+-} 0.6 {mu}M (10-TS). RNA interference showed to be deleterious for both stages of the parasite. In addition, T. brucei-infected mice were fed with Isoxyl, causing a reduction of the parasitemia and an increase of the rodents' survival.« less

Soraphen A, an inhibitor of acetyl CoA carboxylase activity, interferes with fatty acid elongation

PubMed Central

Jump, Donald B.; Torres-Gonzalez, Moises; Olson, L. Karl

2010-01-01

Acetyl CoA carboxylase (ACC1 & ACC2) generates malonyl CoA, a substrate for de novo lipogenesis (DNL) and an inhibitor of mitochondrial fatty acid β-oxidation (FAO). Malonyl CoA is also a substrate for microsomal fatty acid elongation, an important pathway for saturated (SFA), mono- (MUFA) and polyunsaturated fatty acid (PUFA) synthesis. Despite the interest in ACC as a target for obesity and cancer therapy, little attention has been given to the role ACC plays in long chain fatty acid synthesis. This report examines the effect of pharmacological inhibition of ACC on DNL & palmitate (16:0) and linoleate (18:2,n-6) metabolism in HepG2 and LnCap cells. The ACC inhibitor, soraphen A, lowers cellular malonyl CoA, attenuates DNL and the formation of fatty acid elongation products derived from exogenous fatty acids, i.e., 16:0 & 18:2,n-6; IC50 ~ 5 nM. Elevated expression of fatty acid elongases (Elovl5, Elovl6) or desaturases (FADS1, FADS2) failed to override the soraphen A effect on SFA, MUFA or PUFA synthesis. Inhibition of fatty acid elongation leads to the accumulation of 16- and 18-carbon unsaturated fatty acids derived from 16:0 and 18:2,n-6, respectively. Pharmacological inhibition of ACC activity will not only attenuate DNL and induce FAO, but will also attenuate the synthesis of very long chain saturated, mono- and polyunsaturated fatty acids. PMID:21184748

Suppression of the rice fatty-acid desaturase gene OsSSI2 enhances resistance to blast and leaf blight diseases in rice.

PubMed

Jiang, Chang-Jie; Shimono, Masaki; Maeda, Satoru; Inoue, Haruhiko; Mori, Masaki; Hasegawa, Morifumi; Sugano, Shoji; Takatsuji, Hiroshi

2009-07-01

Fatty acids and their derivatives play important signaling roles in plant defense responses. It has been shown that suppressing a gene for stearoyl acyl carrier protein fatty-acid desaturase (SACPD) enhances the resistance of Arabidopsis (SSI2) and soybean to multiple pathogens. In this study, we present functional analyses of a rice homolog of SSI2 (OsSSI2) in disease resistance of rice plants. A transposon insertion mutation (Osssi2-Tos17) and RNAi-mediated knockdown of OsSSI2 (OsSSI2-kd) reduced the oleic acid (18:1) level and increased that of stearic acid (18:0), indicating that OsSSI2 is responsible for fatty-acid desaturase activity. These plants displayed spontaneous lesion formation in leaf blades, retarded growth, slight increase in endogenous free salicylic acid (SA) levels, and SA/benzothiadiazole (BTH)-specific inducible genes, including WRKY45, a key regulator of SA/BTH-induced resistance, in rice. Moreover, the OsSSI2-kd plants showed markedly enhanced resistance to the blast fungus Magnaporthe grisea and leaf-blight bacteria Xanthomonas oryzae pv. oryzae. These results suggest that OsSSI2 is involved in the negative regulation of defense responses in rice, as are its Arabidopsis and soybean counterparts. Microarray analyses identified 406 genes that were differentially expressed (>or=2-fold) in OsSSI2-kd rice plants compared with wild-type rice and, of these, approximately 39% were BTH responsive. Taken together, our results suggest that induction of SA-responsive genes, including WRKY45, is likely responsible for enhanced disease resistance in OsSSI2-kd rice plants.

Hydroxytyrosol prevents reduction in liver activity of Δ-5 and Δ-6 desaturases, oxidative stress, and depletion in long chain polyunsaturated fatty acid content in different tissues of high-fat diet fed mice.

PubMed

Valenzuela, Rodrigo; Echeverria, Francisca; Ortiz, Macarena; Rincón-Cervera, Miguel Ángel; Espinosa, Alejandra; Hernandez-Rodas, María Catalina; Illesca, Paola; Valenzuela, Alfonso; Videla, Luis A

2017-04-11

Eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (AA, C20:4n-6) are long-chain polyunsaturated fatty acids (LCPUFAs) with relevant roles in the organism. EPA and DHA are synthesized from the precursor alpha-linolenic acid (ALA, C18:3n-3), whereas AA is produced from linoleic acid (LA, C18:2n-6) through the action of Δ5 and Δ6-desaturases. High-fat diet (HFD) decreases the activity of both desaturases and LCPUFA accretion in liver and other tissues. Hydroxytyrosol (HT), a natural antioxidant, has an important cytoprotective effects in different cells and tissues. Male mice C57BL/6 J were fed a control diet (CD) (10% fat, 20% protein, 70% carbohydrates) or a HFD (60% fat, 20% protein, 20% carbohydrates) for 12 weeks. Animals were daily supplemented with saline (CD) or 5 mg HT (HFD), and blood and the studied tissues were analyzed after the HT intervention. Parameters studied included liver histology (optical microscopy), activity of hepatic desaturases 5 and 6 (gas-liquid chromatography of methyl esters derivatives) and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase by spectrophotometry), oxidative stress indicators (glutathione, thiobarbituric acid reactants, and the antioxidant capacity of plasma), gene expression assays for sterol regulatory element-binding protein 1c (SREBP-1c) (qPCR and ELISA), and LCPUFA profiles in liver, erythrocyte, brain, heart, and testicle (gas-liquid chromatography). HFD led to insulin resistance and liver steatosis associated with SREBP-1c upregulation, with enhancement in plasma and liver oxidative stress status and diminution in the synthesis and storage of n-6 and n-3 LCPUFAs in the studied tissues, compared to animals given control diet. HT supplementation significantly reduced fat accumulation in liver and plasma as well as tissue metabolic alterations induced by HFD. Furthermore, a normalization of desaturase activities

Cloning and expression analysis of phytoene desaturase and ζ-carotene desaturase genes in Carica papaya.

PubMed

Yan, P; Gao, X Z; Shen, W T; Zhou, P

2011-02-01

The fruit flesh color of papaya is an important nutritional quality trait and is due to the accumulation of carotenoid. To elucidate the carotenoid biosynthesis pathway in Carica papaya, the phytoene desaturase (PDS) and the ζ-carotene desaturase (ZDS) genes were isolated from papaya (named CpPDS and CpZDS) using the rapid amplification of cDNA ends (RACE) approach, and their expression levels were investigated in red- and yellow-fleshed papaya varieties. CpPDS contains a 1749 bp open reading frame coding for 583 amino acids, while CpZDS contains a 1716 bp open reading frame coding for 572 amino acids. The deduced CpPDS and CpZDS proteins contain a conserved dinucleotide-binding site at the N-terminus and a carotenoid-binding domain at the C-terminus. Papaya genome sequence analysis revealed that CpPDS and CpZDS are single copy; the CpPDS was mapped to papaya chromosome LG6, and the CpZDS was mapped to chromosome LG3. Quantitative PCR showed that both CpPDS and CpZDS were expressed in all tissues examined with the highest expression in maturing fruits, and that the expression of CpPDS and CpZDS were higher in red-fleshed fruits than in yellow-fleshed fruits. These results indicated that the differential accumulation of carotenoids in red- and yellow-fleshed papaya varieties might be partly explained by the transcriptional level of CpPDS and CpZDS.

Genome Wide Analysis of Fatty Acid Desaturation and Its Response to Temperature1[OPEN

PubMed Central

Menard, Guillaume N.; Moreno, Jose Martin; Bryant, Fiona M.; Munoz-Azcarate, Olaya; Hassani-Pak, Keywan; Kurup, Smita

2017-01-01

Plants modify the polyunsaturated fatty acid content of their membrane and storage lipids in order to adapt to changes in temperature. In developing seeds, this response is largely controlled by the activities of the microsomal ω-6 and ω-3 fatty acid desaturases, FAD2 and FAD3. Although temperature regulation of desaturation has been studied at the molecular and biochemical levels, the genetic control of this trait is poorly understood. Here, we have characterized the response of Arabidopsis (Arabidopsis thaliana) seed lipids to variation in ambient temperature and found that heat inhibits both ω-6 and ω-3 desaturation in phosphatidylcholine, leading to a proportional change in triacylglycerol composition. Analysis of the 19 parental accessions of the multiparent advanced generation intercross (MAGIC) population showed that significant natural variation exists in the temperature responsiveness of ω-6 desaturation. A combination of quantitative trait locus (QTL) analysis and genome-wide association studies (GWAS) using the MAGIC population suggests that ω-6 desaturation is largely controlled by cis-acting sequence variants in the FAD2 5′ untranslated region intron that determine the expression level of the gene. However, the temperature responsiveness of ω-6 desaturation is controlled by a separate QTL on chromosome 2. The identity of this locus is unknown, but genome-wide association studies identified potentially causal sequence variants within ∼40 genes in an ∼450-kb region of the QTL. PMID:28108698

Genome-Wide Association Study of Genetic Control of Seed Fatty Acid Biosynthesis in Brassica napus

PubMed Central

Gacek, Katarzyna; Bayer, Philipp E.; Bartkowiak-Broda, Iwona; Szala, Laurencja; Bocianowski, Jan; Edwards, David; Batley, Jacqueline

2017-01-01

Fatty acids and their composition in seeds determine oil value for nutritional or industrial purposes and also affect seed germination as well as seedling establishment. To better understand the genetic basis of seed fatty acid biosynthesis in oilseed rape (Brassica napus L.) we applied a genome-wide association study, using 91,205 single nucleotide polymorphisms (SNPs) characterized across a mapping population with high-resolution skim genotyping by sequencing (SkimGBS). We identified a cluster of loci on chromosome A05 associated with oleic and linoleic seed fatty acids. The delineated genomic region contained orthologs of the Arabidopsis thaliana genes known to play a role in regulation of seed fatty acid biosynthesis such as Fatty acyl-ACP thioesterase B (FATB) and Fatty Acid Desaturase (FAD5). This approach allowed us to identify potential functional genes regulating fatty acid composition in this important oil producing crop and demonstrates that this approach can be used as a powerful tool for dissecting complex traits for B. napus improvement programs. PMID:28163710

Characterization of a new GmFAD3A allele in Brazilian CS303TNKCA soybean cultivar.

PubMed

Silva, Luiz Claudio Costa; Bueno, Rafael Delmond; da Matta, Loreta Buuda; Pereira, Pedro Henrique Scarpelli; Mayrink, Danyelle Barbosa; Piovesan, Newton Deniz; Sediyama, Carlos Sigueyuki; Fontes, Elizabeth Pacheco Batista; Cardinal, Andrea J; Dal-Bianco, Maximiller

2018-05-01

We molecularly characterized a new mutation in the GmFAD3A gene associated with low linolenic content in the Brazilian soybean cultivar CS303TNKCA and developed a molecular marker to select this mutation. Soybean is one of the most important crops cultivated worldwide. Soybean oil has 13% palmitic acid, 4% stearic acid, 20% oleic acid, 55% linoleic acid and 8% linolenic acid. Breeding programs are developing varieties with high oleic and low polyunsaturated fatty acids (linoleic and linolenic) to improve the oil oxidative stability and make the varieties more attractive for the soy industry. The main goal of this study was to characterize the low linoleic acid trait in CS303TNKCA cultivar. We sequenced CS303TNKCA GmFAD3A, GmFAD3B and GmFAD3C genes and identified an adenine point deletion in the GmFAD3A exon 5 (delA). This alteration creates a premature stop codon, leading to a truncated protein with just 207 residues that result in a non-functional enzyme. Analysis of enzymatic activity by heterologous expression in yeast support delA as the cause of low linolenic acid content in CS303TNKCA. Thus, we developed a TaqMan genotyping assay to associate delA with low linolenic acid content in segregating populations. Lines homozygous for delA had a linolenic acid content of 3.3 to 4.4%, and the variation at this locus accounted for 50.83 to 73.70% of the phenotypic variation. This molecular marker is a new tool to introgress the low linolenic acid trait into elite soybean cultivars and can be used to combine with high oleic trait markers to produce soybean with enhanced economic value. The advantage of using CS303TNKCA compared to other lines available in the literature is that this cultivar has good agronomic characteristics and is adapted to Brazilian conditions.

Metabolism dysregulation induces a specific lipid signature of nonalcoholic steatohepatitis in patients

PubMed Central

Chiappini, Franck; Coilly, Audrey; Kadar, Hanane; Gual, Philippe; Tran, Albert; Desterke, Christophe; Samuel, Didier; Duclos-Vallée, Jean-Charles; Touboul, David; Bertrand-Michel, Justine; Brunelle, Alain; Guettier, Catherine; Le Naour, François

2017-01-01

Nonalcoholic steatohepatitis (NASH) is a condition which can progress to cirrhosis and hepatocellular carcinoma. Markers for NASH diagnosis are still lacking. We performed a comprehensive lipidomic analysis on human liver biopsies including normal liver, nonalcoholic fatty liver and NASH. Random forests-based machine learning approach allowed characterizing a signature of 32 lipids discriminating NASH with 100% sensitivity and specificity. Furthermore, we validated this signature in an independent group of NASH patients. Then, metabolism dysregulations were investigated in both patients and murine models. Alterations of elongase and desaturase activities were observed along the fatty acid synthesis pathway. The decreased activity of the desaturase FADS1 appeared as a bottleneck, leading upstream to an accumulation of fatty acids and downstream to a deficiency of long-chain fatty acids resulting to impaired phospholipid synthesis. In NASH, mass spectrometry imaging on tissue section revealed the spreading into the hepatic parenchyma of selectively accumulated fatty acids. Such lipids constituted a highly toxic mixture to human hepatocytes. In conclusion, this study characterized a specific and sensitive lipid signature of NASH and positioned FADS1 as a significant player in accumulating toxic lipids during NASH progression. PMID:28436449

Identification of FadAB Complexes Involved in Fatty Acid β-Oxidation in Streptomyces coelicolor and Construction of a Triacylglycerol Overproducing strain

PubMed Central

Menendez-Bravo, Simón; Paganini, Julián; Avignone-Rossa, Claudio; Gramajo, Hugo; Arabolaza, Ana

2017-01-01

Oleaginous microorganisms represent possible platforms for the sustainable production of oleochemicals and biofuels due to their metabolic robustness and the possibility to be engineered. Streptomyces coelicolor is among the narrow group of prokaryotes capable of accumulating triacylglycerol (TAG) as carbon and energy reserve. Although the pathways for TAG biosynthesis in this organism have been widely addressed, the set of genes required for their breakdown have remained elusive so far. Here, we identified and characterized three gene clusters involved in the β-oxidation of fatty acids (FA). The role of each of the three different S. coelicolor FadAB proteins in FA catabolism was confirmed by complementation of an Escherichia coliΔfadBA mutant strain deficient in β-oxidation. In S. coelicolor, the expression profile of the three gene clusters showed variation related with the stage of growth and the presence of FA in media. Flux balance analyses using a corrected version of the current S. coelicolor metabolic model containing detailed TAG biosynthesis reactions suggested the relevance of the identified fadAB genes in the accumulation of TAG. Thus, through the construction and analysis of fadAB knockout mutant strains, we obtained an S. coelicolor mutant that showed a 4.3-fold increase in the TAG content compared to the wild type strain grown under the same culture conditions. PMID:28824562

Postpartum changes in maternal and infant erythrocyte fatty acids are likely to be driven by restoring insulin sensitivity and DHA status.

PubMed

Kuipers, Remko S; Luxwolda, Martine F; Sango, Wicklif S; Kwesigabo, Gideon; Velzing-Aarts, Francien V; Dijck-Brouwer, D A Janneke; Muskiet, Frits A J

2011-06-01

Perinatal changes in maternal glucose and lipid fluxes and de novo lipogenesis (DNL) are driven by hormones and nutrients. Docosahexaenoic acid (DHA) reduces, whereas insulin augments, nuclear abundance of sterol-regulatory-element-binding-protein-1 (SREBP-1), which promotes DNL, stearoyl-CoA-desaturase (SCD, also Δ9-desaturase), fatty acid-(FA)-elongation (Elovl) and FA-desaturation (FADS). Decreasing maternal insulin sensitivity with advancing gestation and compensatory hyperinsulinemia cause augmented postprandial glucose levels, adipose tissue lipolysis and hepatic glucose- and VLDL-production. Hepatic VLDL is composed of dietary, body store and DNL derived FA. Decreasing insulin sensitivity increases the contribution of FA from hepatic-DNL in VLDL-triacylglycerols, and consequently saturated-FA and monounsaturated-FA (MUFA) in maternal serum lipids increase during pregnancy. Although other authors described changes in maternal serum and RBC essential-FA (EFA) after delivery, none went into detail about the changes in non-EFA and the mechanisms behind -and/or functions of- the observed changes. Postpartum FA-changes result from changing enzymatic activities that are influenced by the changing hormonal milieu after delivery and DHA-status. We studied FA-profiles and FA-ratios (as indices for enzymatic activities) of maternal and infant RBC at delivery and after 3 months exclusive breastfeeding in three populations with increasing freshwater-fish intakes. DNL-, SCD- and FADS2-activities decreased after delivery. Elongation-6 (Elovl-6)- and FADS1-activities increased. The most pronounced postpartum changes for mothers were increases in 18:0, linoleic (LA), arachidonic acid (AA) and decreases in 16:0, 18:1ω9 and DHA; and for infants increases in 18:1ω9, 22:5ω3, LA and decreases in 16:0 and AA. Changes were in line with the literature. Postpartum increases in 18:0, and decreases in 16:0 and 18:1ω9, might derive from reduced insulin-promoted DNL-activity, with

Cardiometabolic risk factors are influenced by Stearoyl-CoA Desaturase (SCD) -1 gene polymorphisms and n-3 polyunsaturated fatty acid supplementation.

PubMed

Rudkowska, Iwona; Julien, Pierre; Couture, Patrick; Lemieux, Simone; Tchernof, André; Barbier, Olivier; Vohl, Marie-Claude

2014-05-01

To determine if single nucleotide polymorphisms (SNPs) in stearoyl-CoA desaturase (SCD)-1 gene that encodes a key enzyme for fatty acid metabolism are associated with the response of cardiometabolic risk factors to n-3 PUFA supplementation. Two hundred and ten subjects completed a 2-week run-in period followed by 6-week supplementation with 5 g of fish oil (1.9-2.2 g eicosapentaenoic acid and 1.1 g docosahexaenoic acid). Risk factors were measured pre and post n-3 supplementation. Fatty acid composition of plasma phospholipids was analyzed by GC and the desaturase indices SCD16 (16:1n-7/16:0) and SCD18 (18:1n-9/18:0) were calculated. Genotyping of eight SNPs of the SCD1 gene was performed. N-3 PUFA supplementation decreased plasma triglycerides, as well as SCD16 and SCD18 indices, but increased fasting plasma glucose concentrations. SNPs in SCD1-modified cardiometabolic risk factors pre and post n-3 PUFA supplementation: triglyceride (rs508384, p = 0.0086), IL6 (rs3071, p = 0.0485), C-reactive protein (rs3829160, p = 0.0489), and SCD18 indices (rs2234970, p = 0.0337). A significant interaction effect between the SNP and n-3 PUFA supplementation was also observed for fasting plasma glucose levels (rs508384, p = 0.0262). These results suggest that cardiometabolic risk factors are modulated by genetic variations in the SCD1 gene alone or in combination with n-3 PUFA supplementation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptome Analysis of H2O2-Treated Wheat Seedlings Reveals a H2O2-Responsive Fatty Acid Desaturase Gene Participating in Powdery Mildew Resistance

PubMed Central

Tang, Lichuan; Zhao, Guangyao; Zhu, Mingzhu; Chu, Jinfang; Sun, Xiaohong; Wei, Bo; Zhang, Xiangqi; Jia, Jizeng; Mao, Long

2011-01-01

Hydrogen peroxide (H2O2) plays important roles in plant biotic and abiotic stress responses. However, the effect of H2O2 stress on the bread wheat transcriptome is still lacking. To investigate the cellular and metabolic responses triggered by H2O2, we performed an mRNA tag analysis of wheat seedlings under 10 mM H2O2 treatment for 6 hour in one powdery mildew (PM) resistant (PmA) and two susceptible (Cha and Han) lines. In total, 6,156, 6,875 and 3,276 transcripts were found to be differentially expressed in PmA, Han and Cha respectively. Among them, 260 genes exhibited consistent expression patterns in all three wheat lines and may represent a subset of basal H2O2 responsive genes that were associated with cell defense, signal transduction, photosynthesis, carbohydrate metabolism, lipid metabolism, redox homeostasis, and transport. Among genes specific to PmA, ‘transport’ activity was significantly enriched in Gene Ontology analysis. MapMan classification showed that, while both up- and down- regulations were observed for auxin, abscisic acid, and brassinolides signaling genes, the jasmonic acid and ethylene signaling pathway genes were all up-regulated, suggesting H2O2-enhanced JA/Et functions in PmA. To further study whether any of these genes were involved in wheat PM response, 19 H2O2-responsive putative defense related genes were assayed in wheat seedlings infected with Blumeria graminis f. sp. tritici (Bgt). Eight of these genes were found to be co-regulated by H2O2 and Bgt, among which a fatty acid desaturase gene TaFAD was then confirmed by virus induced gene silencing (VIGS) to be required for the PM resistance. Together, our data presents the first global picture of the wheat transcriptome under H2O2 stress and uncovers potential links between H2O2 and Bgt responses, hence providing important candidate genes for the PM resistance in wheat. PMID:22174904

Stacking of a stearoyl-ACP thioesterase with a dual-silenced palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase in transgenic soybean.

PubMed

Park, Hyunwoo; Graef, George; Xu, Yixiang; Tenopir, Patrick; Clemente, Tom E

2014-10-01

Soybean (Glycine max (L.) Merr) is valued for both its protein and oil, whose seed is composed of 40% and 20% of each component, respectively. Given its high percentage of polyunsaturated fatty acids, linoleic acid and linolenic acid, soybean oil oxidative stability is relatively poor. Historically food processors have employed a partial hydrogenation process to soybean oil as a means to improve both the oxidative stability and functionality in end-use applications. However, the hydrogenation process leads to the formation of trans-fats, which are associated with negative cardiovascular health. As a means to circumvent the need for the hydrogenation process, genetic approaches are being pursued to improve oil quality in oilseeds. In this regard, we report here on the introduction of the mangosteen (Garcinia mangostana) stearoyl-ACP thioesterase into soybean and the subsequent stacking with an event that is dual-silenced in palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase expression in a seed-specific fashion. Phenotypic analyses on transgenic soybean expressing the mangosteen stearoyl-ACP thioesterase revealed increases in seed stearic acid levels up to 17%. The subsequent stacked with a soybean event silenced in both palmitoyl-ACP thioesterase and ∆12 fatty acid desaturase activity, resulted in a seed lipid phenotype of approximately 11%-19% stearate and approximately 70% oleate. The oil profile created by the stack was maintained for four generations under greenhouse conditions and a fifth generation under a field environment. However, in generation six and seven under field conditions, the oleate levels decreased to 30%-40%, while the stearic level remained elevated. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Stearoyl-CoA Desaturase and its Relation to High-Carbohydrate Diets and Obesity

PubMed Central

Flowers, Matthew T.; Ntambi, James M.

2009-01-01

Obesity is currently a worldwide epidemic and public health burden that increases the risk for developing insulin resistance and several chronic diseases such as diabetes, cardiovascular diseases and non-alcoholic fatty liver disease. The multifactorial causes of obesity include several genetic, dietary and lifestyle variables that together result in an imbalance between energy intake and energy expenditure. Dietary approaches to limit fat intake are commonly prescribed to achieve the hypocaloric conditions necessary for weight loss. But dietary fat restriction is often accompanied by increased carbohydrate intake, which can dramatically increase endogenous fatty acid synthesis depending upon carbohydrate composition. Since both dietary and endogenously synthesized fatty acids contribute to the whole-body fatty acid pool, obesity can therefore result from excessive fat or carbohydrate consumption. Stearoyl-Coenzyme A desaturase-1 (SCD1) is a delta-9 fatty acid desaturase that converts saturated fatty acids into monounsaturated fatty acids (MUFA) and this activity is elevated by dietary carbohydrate. Mice lacking Scd1 are protected from obesity and insulin resistance and are characterized by decreased fatty acid synthesis and increased fatty acid oxidation. In this review, we address the association of high-carbohydrate diets with increased SCD activity and summarize the current literature on the subject of SCD1 and body weight regulation. PMID:19166967

Long-chain polyunsaturated fatty acid biosynthesis in the euryhaline herbivorous teleost Scatophagus argus: Functional characterization, tissue expression and nutritional regulation of two fatty acyl elongases.

PubMed

Xie, Dizhi; Chen, Fang; Lin, Siyuan; You, Cuihong; Wang, Shuqi; Zhang, Qinghao; Monroig, Óscar; Tocher, Douglas R; Li, Yuanyou

2016-08-01

Both the spotted scat Scatophagus argus and rabbitfish Siganus canaliculatus belong to the few cultured herbivorous marine teleost, however, their fatty acyl desaturase (Fad) system involved in long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis is different. The S. argus has a △6 Fad, while the rabbitfish has △4 and △6/△5 Fads, which were the first report in vertebrate and marine teleost, respectively. In order to compare the characteristics of elongases of very long-chain fatty acids (Elovl) between them, two Elovl cDNAs were cloned from S. argus in the present study. One has 885bp of open read fragment (ORF) encoding a protein with 294 amino acid (aa) showing Elovl5 activity functionally characterized by heterologous expression in yeast, which was primarily active for the elongation of C18 and C20 PUFAs. The other has 915bp of ORF coding for a 305 aa protein showing Elovl4 activity, which was more efficient in the elongation of C20 and C22 PUFAs. Tissue distribution analyses by RT-PCR showed that elovl5 was highly expressed in the liver compared to other tissues determined, whereas elovl4 transcripts were only detected in the eye. The expression of elovl5 and elovl4 were significantly affected by dietary fatty acid composition, with highest expression of mRNA in the liver and eye of fish fed a diet with an 18:3n-3/18:2n-6 ratio of 1.7:1. These results indicated that the S. argus has a similar Elovl system in the LC-PUFA biosynthetic pathway to that of rabbitfish although their Fad system was different, suggesting that the diversification of fish LC-PUFA biosynthesis specificities is more associated with its Fad system. These new insights expand our knowledge and understanding of the molecular basis and regulation of LC-PUFA biosynthesis in fish. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetic Variants of the FADS Gene Cluster Are Associated with Erythrocyte Membrane LC PUFA Levels in Patients with Mild Cognitive Impairment.

PubMed

Schuchardt, J P; Köbe, T; Witte, V; Willers, J; Gingrich, A; Tesky, V; Pantel, J; Rujescu, D; Illig, T; Flöel, A; Hahn, A

2016-01-01

Long-chain (> 20 C-atoms) polyunsaturated fatty acids (LC PUFAs) of both the omega-6 (n-6) and omega-3 (n-3) series are important for the functional integrity of brain and thereby cognition, memory and mood. Clinical studies observed associations between altered LC PUFA levels and neurodegenerative diseases such as Alzheimer´s disease and its prodromal stage, mild cognitive impairment (MCI). The present study examined the LC PUFA status of MCI patients with specific view on the relative LC n-3 PUFA levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocyte membranes (omega-3 index). 12 single nucleotide polymorphisms (SNPs) of the FADS1, FADS2, and FADS3 gene clusters were genotyped in 111 MCI patients and evaluated associations with PUFA levels in erythrocyte membranes (primary outcome). In addition, the associations between FADS SNPs and LC PUFA levels with serum lipid levels as well as depressive symptoms were examined (secondary outcomes). Minor allele carrier of rs174546, rs174548 (FADS1), rs3834458, rs1535, rs174574, rs174575, rs174576, and rs174578 (FADS2) showed significant higher n-6 and n-3 precursor PUFA levels (linoleic acid, and alpha-linolenic acid, respectively) and lower arachidonic acid (AA) levels in erythrocyte membranes compared to the major allele carriers. Differences in EPA and DHA levels were not significant. Minor allele carriers of rs174574, rs174576 and rs174578 (FADS2) and rs174455 (FADS3) exhibited significant higher triglyceride levels, whereas minor allele carriers for rs174449 and rs174455 (FADS3) exhibited significant higher total- and LDL-cholesterol levels compared to the more common variant. The mean omega-3 index of the study cohort was 6.19 ± 1.55 %. In more than 85 % of the patients, the omega-3 index was below 8 % and in 23 % below 5 %. Moreover, it was shown that a low DHA status and omega-3 index was associated with depressive symptoms (Beck's depression-inventory). These findings indicate an

Brain white matter development is associated with a human-specific haplotype increasing the synthesis of long chain fatty acids.

PubMed

Peters, Bart D; Voineskos, Aristotle N; Szeszko, Philip R; Lett, Tristram A; DeRosse, Pamela; Guha, Saurav; Karlsgodt, Katherine H; Ikuta, Toshikazu; Felsky, Daniel; John, Majnu; Rotenberg, David J; Kennedy, James L; Lencz, Todd; Malhotra, Anil K

2014-04-30

The genetic and molecular pathways driving human brain white matter (WM) development are only beginning to be discovered. Long chain polyunsaturated fatty acids (LC-PUFAs) have been implicated in myelination in animal models and humans. The biosynthesis of LC-PUFAs is regulated by the fatty acid desaturase (FADS) genes, of which a human-specific haplotype is strongly associated with ω-3 and ω-6 LC-PUFA concentrations in blood. To investigate the relationship between LC-PUFA synthesis and human brain WM development, we examined whether this FADS haplotype is associated with age-related WM differences across the life span in healthy individuals 9-86 years of age (n = 207). Diffusion tensor imaging was performed to measure fractional anisotropy (FA), a putative measure of myelination, of the cerebral WM tracts. FADS haplotype status was determined with a single nucleotide polymorphism (rs174583) that tags this haplotype. Overall, normal age-related WM differences were observed, including higher FA values in early adulthood compared with childhood, followed by lower FA values across older age ranges. However, individuals homozygous for the minor allele (associated with lower LC-PUFA concentrations) did not display these normal age-related WM differences (significant age × genotype interactions, p(corrected) < 0.05). These findings suggest that LC-PUFAs are involved in human brain WM development from childhood into adulthood. This haplotype and LC-PUFAs may play a role in myelin-related disorders of neurodevelopmental origin.

Association of desaturase activity and C-reactive protein in European children.

PubMed

Wolters, Maike; Börnhorst, Claudia; Schwarz, Heike; Risé, Patrizia; Galli, Claudio; Moreno, Luis A; Pala, Valeria; Russo, Paola; Veidebaum, Toomas; Tornaritis, Michael; Fraterman, Arno; De Henauw, Stefaan; Eiben, Gabriele; Lissner, Lauren; Molnár, Dénes; Ahrens, Wolfgang

2017-01-01

Desaturase enzymes influence the fatty acid (FA) composition of body tissues and their activity affects the conversion rate of saturated to monounsaturated FA and of polyunsaturated FA (PUFA) to long-chain PUFA. Desaturase activity has further been shown to be associated with inflammation. We investigate the association between delta-9 (D9D), delta-6 (D6D) and delta-5 desaturase (D5D) activity and high-sensitive C-reactive protein (CRP) in young children. In the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) cohort study children were examined at baseline (T0) and after 2 y (T1). D9D, D6D, and D5D activities were estimated from T0 product-precursor FA ratios. CRP was measured at T0 and T1. In a subsample of 1,943 children with available information on FA, CRP, and covariates, the cross-sectional and longitudinal associations of desaturase activity and CRP were analyzed. Cross-sectionally, a D9D increase of 0.01 units was associated with a 11% higher risk of having a serum CRP ≥ Percentile 75 (P75) (OR, 99% CI: 1.11 (1.01; 1.22)) whereas D6D and D5D were not associated with CRP. No significant associations were observed between baseline desaturase activity and CRP 2 y later. Cross-sectionally, our results indicate a positive association of D9D and CRP independent of weight status. High D9D activity may increase the risk of subclinical inflammation which is associated with metabolic disorders. As D9D expression increases with higher intake of saturated FA and carbohydrates, dietary changes may influence D9D activity and thus CRP. However, it remains to be investigated whether there is a causal relationship between D9D activity and CRP.

Identification of QTLs associated with oil content and mapping FAD2 genes and their relative contribution to oil quality in peanut (Arachis hypogaea L.).

PubMed

Pandey, Manish K; Wang, Ming Li; Qiao, Lixian; Feng, Suping; Khera, Pawan; Wang, Hui; Tonnis, Brandon; Barkley, Noelle A; Wang, Jianping; Holbrook, C Corley; Culbreath, Albert K; Varshney, Rajeev K; Guo, Baozhu

2014-12-10

Peanut is one of the major source for human consumption worldwide and its seed contain approximately 50% oil. Improvement of oil content and quality traits (high oleic and low linoleic acid) in peanut could be accelerated by exploiting linked markers through molecular breeding. The objective of this study was to identify QTLs associated with oil content, and estimate relative contribution of FAD2 genes (ahFAD2A and ahFAD2B) to oil quality traits in two recombinant inbred line (RIL) populations. Improved genetic linkage maps were developed for S-population (SunOleic 97R × NC94022) with 206 (1780.6 cM) and T-population (Tifrunner × GT-C20) with 378 (2487.4 cM) marker loci. A total of 6 and 9 QTLs controlling oil content were identified in the S- and T-population, respectively. The contribution of each QTL towards oil content variation ranged from 3.07 to 10.23% in the S-population and from 3.93 to 14.07% in the T-population. The mapping positions for ahFAD2A (A sub-genome) and ahFAD2B (B sub-genome) genes were assigned on a09 and b09 linkage groups. The ahFAD2B gene (26.54%, 25.59% and 41.02% PVE) had higher phenotypic effect on oleic acid (C18:1), linoleic acid (C18:2), and oleic/linoleic acid ratio (O/L ratio) than ahFAD2A gene (8.08%, 6.86% and 3.78% PVE). The FAD2 genes had no effect on oil content. This study identified a total of 78 main-effect QTLs (M-QTLs) with up to 42.33% phenotypic variation (PVE) and 10 epistatic QTLs (E-QTLs) up to 3.31% PVE for oil content and quality traits. A total of 78 main-effect QTLs (M-QTLs) and 10 E-QTLs have been detected for oil content and oil quality traits. One major QTL (more than 10% PVE) was identified in both the populations for oil content with source alleles from NC94022 and GT-C20 parental genotypes. FAD2 genes showed high effect for oleic acid (C18:1), linoleic acid (C18:2), and O/L ratio while no effect on total oil content. The information on phenotypic effect of FAD2 genes for oleic acid, linoleic acid and O

Oxidation of the FAD cofactor to the 8-formyl-derivative in human electron-transferring flavoprotein

PubMed Central

Augustin, Peter; Toplak, Marina; Fuchs, Katharina; Gerstmann, Eva Christine; Prassl, Ruth; Winkler, Andreas; Macheroux, Peter

2018-01-01

The heterodimeric human (h) electron-transferring flavoprotein (ETF) transfers electrons from at least 13 different flavin dehydrogenases to the mitochondrial respiratory chain through a non-covalently bound FAD cofactor. Here, we describe the discovery of an irreversible and pH-dependent oxidation of the 8α-methyl group to 8-formyl-FAD (8f-FAD), which represents a unique chemical modification of a flavin cofactor in the human flavoproteome. Furthermore, a set of hETF variants revealed that several conserved amino acid residues in the FAD-binding pocket of electron-transferring flavoproteins are required for the conversion to the formyl group. Two of the variants generated in our study, namely αR249C and αT266M, cause glutaric aciduria type II, a severe inherited disease. Both of the variants showed impaired formation of 8f-FAD shedding new light on the potential molecular cause of disease development. Interestingly, the conversion of FAD to 8f-FAD yields a very stable flavin semiquinone that exhibited slightly lower rates of electron transfer in an artificial assay system than hETF containing FAD. In contrast, the formation of 8f-FAD enhanced the affinity to human dimethylglycine dehydrogenase 5-fold, indicating that formation of 8f-FAD modulates the interaction of hETF with client enzymes in the mitochondrial matrix. Thus, we hypothesize that the FAD cofactor bound to hETF is subject to oxidation in the alkaline (pH 8) environment of the mitochondrial matrix, which may modulate electron transport between client dehydrogenases and the respiratory chain. This discovery challenges the current concepts of electron transfer processes in mitochondria. PMID:29301933

Cytochrome b5 Reductase 1 Triggers Serial Reactions that Lead to Iron Uptake in Plants.

PubMed

Oh, Young Jun; Kim, Hanul; Seo, Sung Hee; Hwang, Bae Geun; Chang, Yoon Seok; Lee, Junho; Lee, Dong Wook; Sohn, Eun Ju; Lee, Sang Joon; Lee, Youngsook; Hwang, Inhwan

2016-04-04

Rhizosphere acidification is essential for iron (Fe) uptake into plant roots. Plasma membrane (PM) H(+)-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H(+)-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 (CBR1) increases the levels of unsaturated fatty acids, which stimulate PM H(+)-ATPase activity and thus lead to rhizosphere acidification. CBR1-overexpressing (CBR1-OX) Arabidopsis thaliana plants had higher levels of unsaturated fatty acids (18:2 and 18:3), higher PM H(+)-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbr1 loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H(+)-ATPase activity but higher rhizosphere pH. Reduced PM H(+)-ATPase activity in cbr1 could be restored in vitro by addition of unsaturated fatty acids. Transcript levels of CBR1, fatty acids desaturase2 (FAD2), and fatty acids desaturase3 (FAD3) were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H(+)-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Over-expression in Escherichia coli and characterization of two recombinant isoforms of human FAD synthetase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brizio, Carmen; Galluccio, Michele; Wait, Robin

2006-06-09

FAD synthetase (FADS) (EC 2.7.7.2) is a key enzyme in the metabolic pathway that converts riboflavin into the redox cofactor FAD. Two hypothetical human FADSs, which are the products of FLAD1 gene, were over-expressed in Escherichia coli and identified by ESI-MS/MS. Isoform 1 was over-expressed as a T7-tagged protein which had a molecular mass of 63 kDa on SDS-PAGE. Isoform 2 was over-expressed as a 6-His-tagged fusion protein, carrying an extra 84 amino acids at the N-terminal with an apparent molecular mass of 60 kDa on SDS-PAGE. It was purified near to homogeneity from the soluble cell fraction by one-stepmore » affinity chromatography. Both isoforms possessed FADS activity and had a strict requirement for MgCl{sub 2}, as demonstrated using both spectrophotometric and chromatographic methods. The purified recombinant isoform 2 showed a specific activity of 6.8 {+-} 1.3 nmol of FAD synthesized/min/mg protein and exhibited a K {sub M} value for FMN of 1.5 {+-} 0.3 {mu}M. This is First report on characterization of human FADS, and First cloning and over-expression of FADS from an organism higher than yeast.« less

Survey of the total fatty acid and triacylglycerol composition and content of 30 duckweed species and cloning of a Δ6-desaturase responsible for the production of γ-linolenic and stearidonic acids in Lemna gibba

PubMed Central

2013-01-01

Background Duckweeds, i.e., members of the Lemnoideae family, are amongst the smallest aquatic flowering plants. Their high growth rate, aquatic habit and suitability for bio-remediation make them strong candidates for biomass production. Duckweeds have been studied for their potential as feedstocks for bioethanol production; however, less is known about their ability to accumulate reduced carbon as fatty acids (FA) and oil. Results Total FA profiles of thirty duckweed species were analysed to assess the natural diversity within the Lemnoideae. Total FA content varied between 4.6% and 14.2% of dry weight whereas triacylglycerol (TAG) levels varied between 0.02% and 0.15% of dry weight. Three FA, 16:0 (palmitic), 18:2Δ9,12 (Linoleic acid, or LN) and 18:3Δ9,12,15 (α-linolenic acid, or ALA) comprise more than 80% of total duckweed FA. Seven Lemna and two Wolffiela species also accumulate polyunsaturated FA containing Δ6-double bonds, i.e., GLA and SDA. Relative to total FA, TAG is enriched in saturated FA and deficient in polyunsaturated FA, and only five Lemna species accumulate Δ6-FA in their TAG. A putative Δ6-desaturase designated LgDes, with homology to a family of front-end Δ6-FA and Δ8-spingolipid desaturases, was identified in the assembled DNA sequence of Lemna gibba. Expression of a synthetic LgDes gene in Nicotiana benthamiana resulted in the accumulation of GLA and SDA, confirming it specifies a Δ6-desaturase. Conclusions Total accumulation of FA varies three-fold across the 30 species of Lemnoideae surveyed. Nine species contain GLA and SDA which are synthesized by a Δ6 front-end desaturase, but FA composition is otherwise similar. TAG accumulates up to 0.15% of total dry weight, comparable to levels found in the leaves of terrestrial plants. Polyunsaturated FA is underrepresented in TAG, and the Δ6-FA GLA and SDA are found in the TAG of only five of the nine Lemna species that produce them. When present, GLA is enriched and SDA diminished

Development of markers for Delta9-Stearoyl-ACP-Desaturase (SAD) to screen for cold acclimation

USDA-ARS?s Scientific Manuscript database

Delta 9-Stearoyl-acyl carrier protein (ACP) desaturase (SAD) is an important enzyme of fatty acid biosynthesis in higher plants. Located in the plastid stroma, SAD catalyzes the desaturation of stearoyl-ACP to oleyl-ACP. SAD plays a key role in determining the ratio of saturated fatty acids to unsat...

Stearoyl-CoA desaturase activity in bovine cumulus cells protects the oocyte against saturated fatty acid stress

PubMed Central

Aardema, Hilde; van Tol, Helena T. A.; Wubbolts, Richard W.; Brouwers, Jos F. H. M.; Gadella, Bart M.; Roelen, Bernard A. J.

2017-01-01

Abstract Metabolic rich and poor conditions are both characterized by elevated free fatty acid levels and have been associated with impaired female fertility. In particular, saturated free fatty acids have a dose-dependent negative impact on oocyte developmental competence, while monounsaturated free fatty acids appear less harmful. Cumulus cells seem to protect the oocyte against free fatty acids, and the aim of this study was to determine the mechanism behind this protection In particular, the role of the enzyme stearoyl-CoA desaturase (SCD) that converts saturated into monounsaturated fatty acids was investigated. SCD gene and protein were abundantly expressed in cumulus cells, but expression was low in oocytes. The level of SCD protein expression in cumulus cells did not change when COCs were exposed to saturated stearic acid during maturation. SCD inhibition in the presence of stearic acid significantly reduced the developmental competence of oocytes and increased the incidence of apoptosis in cumulus cells. The esterified oleic/stearic acid ratio of the neutral lipid fraction in cumulus cells decreased in the presence of SCD inhibitors when COCs were exposed to saturated free fatty acids during maturation, indicating the SCD-specific conversion of saturated fatty acids under noninhibiting conditions. The observation that cumulus cells can desaturate the potentially toxic stearic acid into oleic acid via SCD activity provides a mechanistic insight into how the cumulus cells protect the oocyte against toxicity by saturated fatty acid. PMID:28486699

Dietary fish oil supplements increase tissue n-3 fatty acid composition and expression of delta-6 desaturase and elongase-2 in Jade Tiger hybrid abalone.

PubMed

Mateos, Hintsa T; Lewandowski, Paul A; Su, Xiao Q

2011-08-01

This study was conducted to investigate the effects of fish oil (FO) supplements on fatty acid composition and the expression of ∆6 desaturase and elongase 2 genes in Jade Tiger abalone. Five test diets were formulated to contain 0.5, 1.0, 1.5, 2.0 and 2.5% of FO respectively, and the control diet was the normal commercial abalone diet with no additional FO supplement. The muscle, gonad and digestive glands (DG) of abalone fed with all of the five test diets showed significantly high levels of total n-3 polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA), docosapentaenoic acid n-3 (DPAn-3), and docosahexaenoic acid (DHA) than the control group. In all three types of tissue, abalone fed diet supplemented with 1.5% FO showed the highest level of these fatty acids (P < 0.05). For DPAn-3 the higher level was also found in muscle and gonad of abalone fed diet supplemented with 2% FO (P < 0.05). Elongase 2 expression was markedly higher in the muscle of abalone fed diet supplemented with 1.5% FO (P < 0.05), followed by the diet containing 2% FO supplement. For ∆6 desaturase, significantly higher expression was observed in muscle of abalone fed with diet containing 0.5% FO supplement (P < 0.05). Supplementation with FO in the normal commercial diet can significantly improve long chain n-3 PUFA level in cultured abalone, with 1.5% being the most effective supplementation level.

Evaluation of functioning of mitochondrial electron transport chain with NADH and FAD autofluorescence

PubMed

Danylovych, H V

2016-01-01

We prove the feasibility of evaluation of mitochondrial electron transport chain function in isolated mitochondria of smooth muscle cells of rats from uterus using fluorescence of NADH and FAD coenzymes. We found the inversely directed changes in FAD and NADH fluorescence intensity under normal functioning of mitochondrial electron transport chain. The targeted effect of inhibitors of complex I, III and IV changed fluorescence of adenine nucleotides. Rotenone (5 μM) induced rapid increase in NADH fluorescence due to inhibition of complex I, without changing in dynamics of FAD fluorescence increase. Antimycin A, a complex III inhibitor, in concentration of 1 μg/ml caused sharp increase in NADH fluorescence and moderate increase in FAD fluorescence in comparison to control. NaN3 (5 mM), a complex IV inhibitor, and CCCP (10 μM), a protonophore, caused decrease in NADH and FAD fluorescence. Moreover, all the inhibitors caused mitochondria swelling. NO donors, e.g. 0.1 mM sodium nitroprusside and sodium nitrite similarly to the effects of sodium azide. Energy-dependent Ca2+ accumulation in mitochondrial matrix (in presence of oxidation substrates and Mg-ATP2- complex) is associated with pronounced drop in NADH and FAD fluorescence followed by increased fluorescence of adenine nucleotides, which may be primarily due to Ca2+- dependent activation of dehydrogenases of citric acid cycle. Therefore, the fluorescent signal of FAD and NADH indicates changes in oxidation state of these nucleotides in isolated mitochondria, which may be used to assay the potential of effectors of electron transport chain.

Inducing effect of clofibric acid on stearoyl-CoA desaturase in intestinal mucosa of rats.

PubMed

Yamazaki, Tohru; Kadokura, Makiko; Mutoh, Yuki; Sakamoto, Takeshi; Okazaki, Mari; Mitsumoto, Atsushi; Kawashima, Yoichi; Kudo, Naomi

2014-12-01

Fibrates have been reported to elevate the hepatic proportion of oleic acid (18:1n-9) through inducing stearoyl-CoA desaturase (SCD). Despite abundant studies on the regulation of SCD in the liver, little is known about this issue in the small intestine. The present study aimed to investigate the effect of clofibric acid on the fatty acid profile, particularly monounsaturated fatty acids (MUFA), and the SCD expression in intestinal mucosa. Treatment of rats with a diet containing 0.5% (w/w) clofibric acid for 7 days changed the MUFA profile of total lipids in intestinal mucosa; the proportion of 18:1n-9 was significantly increased, whereas those of palmitoleic (16:1n-7) and cis-vaccenic (18:1n-7) acids were not changed. Upon the treatment with clofibric acid, SCD was induced and the gene expression of SCD1, SCD2, and fatty acid elongase (Elovl) 6 was up-regulated, but that of Elovl5 was unaffected. Fat-free diet feeding for 28 days increased the proportions of 16:1n-7 and 18:1n-7, but did not effectively change that of 18:1n-9, in intestinal mucosa. Fat-free diet feeding up-regulated the gene expression of SCD1, but not that of SCD2, Elovl6, or Elovl5. These results indicate that intestinal mucosa significantly changes its MUFA profile in response to challenges by clofibric acid and a fat-free diet and suggest that up-regulation of the gene expression of SCD along with Elovl6 is indispensable to elevate the proportion of 18:1n-9 in intestinal mucosa.

An oleate hydroxylase from the fungus Claviceps purpurea: cloning, functional analysis, and expression in Arabidopsis.

PubMed

Meesapyodsuk, Dauenpen; Qiu, Xiao

2008-07-01

Claviceps purpurea, a fungal pathogen responsible for ergot diseases in many agriculturally important cereal crops, produces high levels of ricinoleic acid (12-hydroxyoctadec-cis-9-enoic acid) in its sclerotia. It has been believed for many years that the biosynthesis of this fatty acid in C. purpurea involves a hydration process with linoleic acid as the substrate. Using degenerate polymerase chain reaction, we cloned a gene from the sclerotia encoding an enzyme (CpFAH) that has high sequence similarity to the C. purpurea oleate desaturase, but only low similarity to plant oleate hydroxylases. Functional analysis of CpFAH in yeast (Saccharomyces cerevisiae) indicated it acted predominantly as a hydroxylase, introducing hydroxyl groups at the 12-position of oleic acid and palmitoleic acid. As well, it showed Delta(12) desaturase activities on 16C and 18C monounsaturated fatty acids and, to a much lesser extent, omega(3) desaturase activities on ricinoleic acid. Heterologous expression of CpFAH under the guidance of a seed-specific promoter in Arabidopsis (Arabidopsis thaliana) wild-type and mutant (fad2/fae1) plants resulted in the accumulation of relatively higher levels of hydroxyl fatty acids in seeds. These data indicate that the biosynthesis of ricinoleic acid in C. purpurea is catalyzed by the fungal desaturase-like hydroxylase, and CpFAH, the first Delta(12) oleate hydroxylase of nonplant origin, is a good candidate for the transgenic production of hydroxyl fatty acids in oilseed crops.

Purification of electron-transferring flavoprotein from Megasphaera elsdenii and binding of additional FAD with an unusual absorption spectrum.

PubMed

Sato, Kyosuke; Nishina, Yasuzo; Shiga, Kiyoshi

2003-11-01

Electron-transferring flavoprotein (ETF), its redox partner flavoproteins, i.e., D-lactate dehydrogenase and butyryl-CoA dehydrogenase, and another well-known flavoprotein, flavodoxin, were purified from the same starting cell paste of an anaerobic bacterium, Megasphaera elsdenii. The purified ETF contained one mol FAD/mol ETF as the sole non-protein component and bound almost one mol of additional FAD. This preparation is a better subject for investigations of M. elsdenii ETF than the previously isolated ETF, which contains varying amounts of FAD and varying percentages of modified flavins such as 6-OH-FAD and 8-OH-FAD. The additionally bound FAD shows an anomalous absorption spectrum with strong absorption around 400 nm. This spectral change is not due to a chemical modification of the flavin ring because the flavin released by KBr or guanidine hydrochloride is normal FAD. It is also not due to unknown small molecules because the same spectrum appears when ETF is reconstituted from its guanidine-denatured subunits and FAD. A similar anomalous spectrum was observed for AMP-free pig ETF under acidic conditions, suggesting a common flavin environment between pig and M. elsdenii ETFs.

StearoylCoA Desaturase-5: A Novel Regulator of Neuronal Cell Proliferation and Differentiation

PubMed Central

Sinner, Debora I.; Kim, Gretchun J.; Henderson, Gregory C.; Igal, R. Ariel

2012-01-01

Recent studies have demonstrated that human stearoylCoA desaturase-1 (SCD1), a Δ9-desaturase that converts saturated fatty acids (SFA) into monounsaturated fatty acids, controls the rate of lipogenesis, cell proliferation and tumorigenic capacity in cancer cells. However, the biological function of stearoylCoA desaturase-5 (SCD5), a second isoform of human SCD that is highly expressed in brain, as well as its potential role in human disease, remains unknown. In this study we report that the constitutive overexpression of human SCD5 in mouse Neuro2a cells, a widely used cell model of neuronal growth and differentiation, displayed a greater n-7 MUFA-to-SFA ratio in cell lipids compared to empty-vector transfected cells (controls). De novo synthesis of phosphatidylcholine and cholesterolesters was increased whereas phosphatidylethanolamine and triacylglycerol formation was reduced in SCD5-expressing cells with respect to their controls, suggesting a differential use of SCD5 products for lipogenic reactions. We also observed that SCD5 expression markedly accelerated the rate of cell proliferation and suppressed the induction of neurite outgrowth, a typical marker of neuronal differentiation, by retinoic acid indicating that the desaturase plays a key role in the mechanisms of cell division and differentiation. Critical signal transduction pathways that are known to modulate these processes, such epidermal growth factor receptor (EGFR)Akt/ERK and Wnt, were affected by SCD5 expression. Epidermal growth factor-induced phosphorylation of EGFR, Akt and ERK was markedly blunted in SCD5-expressing cells. Furthermore, the activity of canonical Wnt was reduced whereas the non-canonical Wnt was increased by the presence of SCD5 activity. Finally, SCD5 expression increased the secretion of recombinant Wnt5a, a non-canonical Wnt, whereas it reduced the cellular and secreted levels of canonical Wnt7b. Our data suggest that, by a coordinated modulation of key lipogenic pathways and

Bacterial Production, Characterization and Protein Modeling of a Novel Monofuctional Isoform of FAD Synthase in Humans: An Emergency Protein?

PubMed

Leone, Piero; Galluccio, Michele; Barbiroli, Alberto; Eberini, Ivano; Tolomeo, Maria; Vrenna, Flavia; Gianazza, Elisabetta; Iametti, Stefania; Bonomi, Francesco; Indiveri, Cesare; Barile, Maria

2018-01-06

FAD synthase (FADS, EC 2.7.7.2) is the last essential enzyme involved in the pathway of biosynthesis of Flavin cofactors starting from Riboflavin (Rf). Alternative splicing of the human FLAD1 gene generates different isoforms of the enzyme FAD synthase. Besides the well characterized isoform 1 and 2, other FADS isoforms with different catalytic domains have been detected, which are splice variants. We report the characterization of one of these novel isoforms, a 320 amino acid protein, consisting of the sole C-terminal 3'-phosphoadenosine 5'-phosphosulfate (PAPS) reductase domain (named FADS6). This isoform has been previously detected in Riboflavin-Responsive (RR-MADD) and Non-responsive Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) patients with frameshift mutations of FLAD1 gene. To functionally characterize the hFADS6, it has been over-expressed in Escherichia coli and purified with a yield of 25 mg·L -1 of cell culture. The protein has a monomeric form, it binds FAD and is able to catalyze FAD synthesis (k cat about 2.8 min -1 ), as well as FAD pyrophosphorolysis in a strictly Mg 2+ -dependent manner. The synthesis of FAD is inhibited by HgCl₂. The enzyme lacks the ability to hydrolyze FAD. It behaves similarly to PAPS. Combining threading and ab-initio strategy a 3D structural model for such isoform has been built. The relevance to human physio-pathology of this FADS isoform is discussed.

Anthocyanins do not influence long-chain n-3 fatty acid status: studies in cells, rodents and humans.

PubMed

Vauzour, David; Tejera, Noemi; O'Neill, Colette; Booz, Valeria; Jude, Baptiste; Wolf, Insa M A; Rigby, Neil; Silvan, Jose Manuel; Curtis, Peter J; Cassidy, Aedin; de Pascual-Teresa, Sonia; Rimbach, Gerald; Minihane, Anne Marie

2015-03-01

Increased tissue status of the long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) is associated with cardiovascular and cognitive benefits. Limited epidemiological and animal data suggest that flavonoids, and specifically anthocyanins, may increase EPA and DHA levels, potentially by increasing their synthesis from the shorter-chain n-3 PUFA, α-linolenic acid. Using complimentary cell, rodent and human studies we investigated the impact of anthocyanins and anthocyanin-rich foods/extracts on plasma and tissue EPA and DHA levels and on the expression of fatty acid desaturase 2 (FADS2), which represents the rate limiting enzymes in EPA and DHA synthesis. In experiment 1, rats were fed a standard diet containing either palm oil or rapeseed oil supplemented with pure anthocyanins for 8 weeks. Retrospective fatty acid analysis was conducted on plasma samples collected from a human randomized controlled trial where participants consumed an elderberry extract for 12 weeks (experiment 2). HepG2 cells were cultured with α-linolenic acid with or without select anthocyanins and their in vivo metabolites for 24 h and 48 h (experiment 3). The fatty acid composition of the cell membranes, plasma and liver tissues were analyzed by gas chromatography. Anthocyanins and anthocyanin-rich food intake had no significant impact on EPA or DHA status or FADS2 gene expression in any model system. These data indicate little impact of dietary anthocyanins on n-3 PUFA distribution and suggest that the increasingly recognized benefits of anthocyanins are unlikely to be the result of a beneficial impact on tissue fatty acid status. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Anthocyanins do not influence long-chain n-3 fatty acid status: studies in cells, rodents and humans☆

PubMed Central

Vauzour, David; Tejera, Noemi; O'Neill, Colette; Booz, Valeria; Jude, Baptiste; Wolf, Insa M.A.; Rigby, Neil; Silvan, Jose Manuel; Curtis, Peter J.; Cassidy, Aedin; de Pascual-Teresa, Sonia; Rimbach, Gerald; Minihane, Anne Marie

2015-01-01

Increased tissue status of the long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) is associated with cardiovascular and cognitive benefits. Limited epidemiological and animal data suggest that flavonoids, and specifically anthocyanins, may increase EPA and DHA levels, potentially by increasing their synthesis from the shorter-chain n-3 PUFA, α-linolenic acid. Using complimentary cell, rodent and human studies we investigated the impact of anthocyanins and anthocyanin-rich foods/extracts on plasma and tissue EPA and DHA levels and on the expression of fatty acid desaturase 2 (FADS2), which represents the rate limiting enzymes in EPA and DHA synthesis. In experiment 1, rats were fed a standard diet containing either palm oil or rapeseed oil supplemented with pure anthocyanins for 8 weeks. Retrospective fatty acid analysis was conducted on plasma samples collected from a human randomized controlled trial where participants consumed an elderberry extract for 12 weeks (experiment 2). HepG2 cells were cultured with α-linolenic acid with or without select anthocyanins and their in vivo metabolites for 24 h and 48 h (experiment 3). The fatty acid composition of the cell membranes, plasma and liver tissues were analyzed by gas chromatography. Anthocyanins and anthocyanin-rich food intake had no significant impact on EPA or DHA status or FADS2 gene expression in any model system. These data indicate little impact of dietary anthocyanins on n-3 PUFA distribution and suggest that the increasingly recognized benefits of anthocyanins are unlikely to be the result of a beneficial impact on tissue fatty acid status. PMID:25573539

Crystallization and preliminary X-ray data of the FadA adhesin from Fusobacterium nucleatum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nithianantham, Stanley; Xu, Minghua; Wu, Nan

2006-12-01

The FadA adhesin from F. nucleatum, which is involved in bacterial attachment and invasion of human oral epithelial cells, has been crystallized in space group P6{sub 1} or P6{sub 5}, and X-ray data have been collected to 1.9 Å resolution. Fusobacterium nucleatum is a Gram-negative anaerobe prevalent in the oral cavity that is associated with periodontal disease, preterm birth and infections in other parts of the human body. The bacteria attach to and invade epithelial and endothelial cells in the gum tissue and elsewhere via a 13.7 kDa adhesin protein FadA (Fusobacterium adhesin A). FadA exists in two forms: themore » intact form (pre-FadA), consisting of 129 amino acids, and the mature form (mFadA), which lacks an 18-residue signal sequence. Both forms have been expressed in Escherichia coli and purified. mFadA has been crystallized. The crystals belong to the hexagonal space group P6{sub 1} or P6{sub 5}, with unit-cell parameters a = b = 59.3, c = 125.7 Å and one molecule per asymmetric unit. The crystals exhibit an unusually high solvent content of 74%. Synchrotron X-ray data have been collected to 1.9 Å. The crystals are suitable for X-ray structure determination. The crystal structure of FadA may provide a basis for the development of therapeutic agents to combat periodontal disease and other infections associated with F. nucleatum.« less

Discovery of antimicrobial compounds targeting bacterial type FAD synthetases.

PubMed

Sebastián, María; Anoz-Carbonell, Ernesto; Gracia, Begoña; Cossio, Pilar; Aínsa, José Antonio; Lans, Isaías; Medina, Milagros

2018-12-01

The increase of bacterial strains resistant to most of the available antibiotics shows a need to explore novel antibacterial targets to discover antimicrobial drugs. Bifunctional bacterial FAD synthetases (FADSs) synthesise the flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These cofactors act in vital processes as part of flavoproteins, making FADS an essential enzyme. Bacterial FADSs are potential antibacterial targets because of differences to mammalian enzymes, particularly at the FAD producing site. We have optimised an activity-based high throughput screening assay targeting Corynebacterium ammoniagenes FADS (CaFADS) that identifies inhibitors of its different activities. We selected the three best high-performing inhibitors of the FMN:adenylyltransferase activity (FMNAT) and studied their inhibition mechanisms and binding properties. The specificity of the CaFADS hits was evaluated by studying also their effect on the Streptococcus pneumoniae FADS activities, envisaging differences that can be used to discover species-specific antibacterial drugs. The antimicrobial effect of these compounds was also evaluated on C. ammoniagenes, S. pneumoniae, and Mycobacterium tuberculosis cultures, finding hits with favourable antimicrobial properties.

Stabilization of the yeast desaturase system by low levels of oxygen

NASA Technical Reports Server (NTRS)

Volkmann, C. M.; Klein, H. P.

1983-01-01

The stability of particulate palmitoyl-CoA desaturase preparations from anaerobically grown yeast cells was increased by exposure to low levels of oxygen. The stabilizing effect of oxygen may be based upon the increased amounts of palmitoleic acid and ergosterol that become available to the cells. These results suggest the evolutinary appearance of this system at a time when atmospheric oxygen was at a low level.

Eliminating expression of erucic acid-encoding loci allows the identification of "hidden" QTL contributing to oil quality fractions and oil content in Brassica juncea (Indian mustard).

PubMed

Jagannath, Arun; Sodhi, Yashpal Singh; Gupta, Vibha; Mukhopadhyay, Arundhati; Arumugam, Neelakantan; Singh, Indira; Rohatgi, Soma; Burma, Pradeep Kumar; Pradhan, Akshay Kumar; Pental, Deepak

2011-04-01

Oil content and oil quality fractions (viz., oleic, linoleic and linolenic acid) are strongly influenced by the erucic acid pathway in oilseed Brassicas. Low levels of erucic acid in seed oil increases oleic acid content to nutritionally desirable levels, but also increases the linoleic and linolenic acid fractions and reduces oil content in Indian mustard (Brassica juncea). Analysis of phenotypic variability for oil quality fractions among a high-erucic Indian variety (Varuna), a low-erucic east-European variety (Heera) and a zero-erucic Indian variety (ZE-Varuna) developed by backcross breeding in this study indicated that lower levels of linoleic and linolenic acid in Varuna are due to substrate limitation caused by an active erucic acid pathway and not due to weaker alleles or enzyme limitation. To identify compensatory loci that could be used to increase oil content and maintain desirable levels of oil quality fractions under zero-erucic conditions, we performed Quantitative Trait Loci (QTL) mapping for the above traits on two independent F1 doubled haploid (F1DH) mapping populations developed from a cross between Varuna and Heera. One of the populations comprised plants segregating for erucic acid content (SE) and was used earlier for construction of a linkage map and QTL mapping of several yield-influencing traits in B. juncea. The second population consisted of zero-erucic acid individuals (ZE) for which, an Amplified Fragment Length Polymorphism (AFLP)-based framework linkage map was constructed in the present study. By QTL mapping for oil quality fractions and oil content in the ZE population, we detected novel loci contributing to the above traits. These loci did not co-localize with mapped locations of the fatty acid desaturase 2 (FAD2), fatty acid desaturase 3 (FAD3) or fatty acid elongase (FAE) genes unlike those of the SE population wherein major QTL were found to coincide with mapped locations of the FAE genes. Some of the new loci identified in the

Half-of-the-Sites Reactivity of the Castor Δ9-18:0-Acyl Carrier Protein Desaturase.

PubMed

Liu, Qin; Chai, Jin; Moche, Martin; Guy, Jodie; Lindqvist, Ylva; Shanklin, John

2015-09-01

Fatty acid desaturases regulate the unsaturation status of cellular lipids. They comprise two distinct evolutionary lineages, a soluble class found in the plastids of higher plants and an integral membrane class found in plants, yeast (Saccharomyces cerevisiae), animals, and bacteria. Both classes exhibit a dimeric quaternary structure. Here, we test the functional significance of dimeric organization of the soluble castor Δ9-18:0-acyl carrier protein desaturase, specifically, the hypothesis that the enzyme uses an alternating subunit half-of-the-sites reactivity mechanism whereby substrate binding to one subunit is coordinated with product release from the other subunit. Using a fluorescence resonance energy transfer assay, we demonstrated that dimers stably associate at concentrations typical of desaturase assays. An active site mutant T104K/S202E, designed to occlude the substrate binding cavity, was expressed, purified, and its properties validated by x-ray crystallography, size exclusion chromatography, and activity assay. Heterodimers comprising distinctly tagged wild-type and inactive mutant subunits were purified at 1:1 stoichiometry. Despite having only one-half the number of active sites, purified heterodimers exhibit equivalent activity to wild-type homodimers, consistent with half-of-the-sites reactivity. However, because multiple rounds of turnover were observed, we conclude that substrate binding to one subunit is not required to facilitate product release from the second subunit. The observed half-of-the-sites reactivity could potentially buffer desaturase activity from oxidative inactivation. That soluble desaturases require only one active subunit per dimer for full activity represents a mechanistic difference from the membrane class of desaturases such as the Δ9-acyl-CoA, Ole1p, from yeast, which requires two catalytically competent subunits for activity. © 2015 American Society of Plant Biologists. All Rights Reserved.

The intrinsic fluorescence of FAD and its application in analytical chemistry: a review

NASA Astrophysics Data System (ADS)

Galbán, Javier; Sanz-Vicente, Isabel; Navarro, Jesús; de Marcos, Susana

2016-12-01

This review (with 106 references) mainly deals with the analytical applications of flavin-adenine dinucleotide (FAD) fluorescence. In the first section, the spectroscopic properties of this compound are reviewed at the light of his different acid-base, oxidation and structural forms; the chemical and spectroscopic properties of flavin mononucleotide (FMN) and other flavins will be also briefly discussed. The second section discusses how the properties of FAD fluorescence changes in flavoenzymes (FvEs), again considering the different chemical and structural forms; the glucose oxidase (GOx) and the choline oxidase (ChOx) cases will be commented. Since almost certainly the most reported analytical application of FAD fluorescence is as an auto-indicator in enzymatic methods catalysed by FvE oxidoreductases, it is important to know how the concentrations of the different forms of FAD changes along the reaction and, consequently, the fluorescence and the analytical signals. An approach to do this will be presented in section 3. The fourth part of the paper compiles the analytical applications which have been reported until now based in these fluorescence properties. Finally, some suggestions about tentative future research are also given.

The intrinsic fluorescence of FAD and its application in analytical chemistry: a review.

PubMed

Galbán, Javier; Sanz-Vicente, Isabel; Navarro, Jesús; de Marcos, Susana

2016-12-19

This review (with 106 references) mainly deals with the analytical applications of flavin-adenine dinucleotide (FAD) fluorescence. In the first section, the spectroscopic properties of this compound are reviewed at the light of his different acid-base, oxidation and structural forms; the chemical and spectroscopic properties of flavin mononucleotide (FMN) and other flavins will be also briefly discussed. The second section discusses how the properties of FAD fluorescence changes in flavoenzymes (FvEs), again considering the different chemical and structural forms; the glucose oxidase (GOx) and the choline oxidase (ChOx) cases will be commented. Since almost certainly the most reported analytical application of FAD fluorescence is as an auto-indicator in enzymatic methods catalysed by FvE oxidoreductases, it is important to know how the concentrations of the different forms of FAD changes along the reaction and, consequently, the fluorescence and the analytical signals. An approach to do this will be presented in section 3. The fourth part of the paper compiles the analytical applications which have been reported until now based in these fluorescence properties. Finally, some suggestions about tentative future research are also given.

Evolutionary divergence of chloroplast FAD synthetase proteins

PubMed Central

2010-01-01

Background Flavin adenine dinucleotide synthetases (FADSs) - a group of bifunctional enzymes that carry out the dual functions of riboflavin phosphorylation to produce flavin mononucleotide (FMN) and its subsequent adenylation to generate FAD in most prokaryotes - were studied in plants in terms of sequence, structure and evolutionary history. Results Using a variety of bioinformatics methods we have found that FADS enzymes localized to the chloroplasts, which we term as plant-like FADS proteins, are distributed across a variety of green plant lineages and constitute a divergent protein family clearly of cyanobacterial origin. The C-terminal module of these enzymes does not contain the typical riboflavin kinase active site sequence, while the N-terminal module is broadly conserved. These results agree with a previous work reported by Sandoval et al. in 2008. Furthermore, our observations and preliminary experimental results indicate that the C-terminus of plant-like FADS proteins may contain a catalytic activity, but different to that of their prokaryotic counterparts. In fact, homology models predict that plant-specific conserved residues constitute a distinct active site in the C-terminus. Conclusions A structure-based sequence alignment and an in-depth evolutionary survey of FADS proteins, thought to be crucial in plant metabolism, are reported, which will be essential for the correct annotation of plant genomes and further structural and functional studies. This work is a contribution to our understanding of the evolutionary history of plant-like FADS enzymes, which constitute a new family of FADS proteins whose C-terminal module might be involved in a distinct catalytic activity. PMID:20955574

Riboflavin-Responsive and -Non-responsive Mutations in FAD Synthase Cause Multiple Acyl-CoA Dehydrogenase and Combined Respiratory-Chain Deficiency.

PubMed

Olsen, Rikke K J; Koňaříková, Eliška; Giancaspero, Teresa A; Mosegaard, Signe; Boczonadi, Veronika; Mataković, Lavinija; Veauville-Merllié, Alice; Terrile, Caterina; Schwarzmayr, Thomas; Haack, Tobias B; Auranen, Mari; Leone, Piero; Galluccio, Michele; Imbard, Apolline; Gutierrez-Rios, Purificacion; Palmfeldt, Johan; Graf, Elisabeth; Vianey-Saban, Christine; Oppenheim, Marcus; Schiff, Manuel; Pichard, Samia; Rigal, Odile; Pyle, Angela; Chinnery, Patrick F; Konstantopoulou, Vassiliki; Möslinger, Dorothea; Feichtinger, René G; Talim, Beril; Topaloglu, Haluk; Coskun, Turgay; Gucer, Safak; Botta, Annalisa; Pegoraro, Elena; Malena, Adriana; Vergani, Lodovica; Mazzà, Daniela; Zollino, Marcella; Ghezzi, Daniele; Acquaviva, Cecile; Tyni, Tiina; Boneh, Avihu; Meitinger, Thomas; Strom, Tim M; Gregersen, Niels; Mayr, Johannes A; Horvath, Rita; Barile, Maria; Prokisch, Holger

2016-06-02

Multiple acyl-CoA dehydrogenase deficiencies (MADDs) are a heterogeneous group of metabolic disorders with combined respiratory-chain deficiency and a neuromuscular phenotype. Despite recent advances in understanding the genetic basis of MADD, a number of cases remain unexplained. Here, we report clinically relevant variants in FLAD1, which encodes FAD synthase (FADS), as the cause of MADD and respiratory-chain dysfunction in nine individuals recruited from metabolic centers in six countries. In most individuals, we identified biallelic frameshift variants in the molybdopterin binding (MPTb) domain, located upstream of the FADS domain. Inasmuch as FADS is essential for cellular supply of FAD cofactors, the finding of biallelic frameshift variants was unexpected. Using RNA sequencing analysis combined with protein mass spectrometry, we discovered FLAD1 isoforms, which only encode the FADS domain. The existence of these isoforms might explain why affected individuals with biallelic FLAD1 frameshift variants still harbor substantial FADS activity. Another group of individuals with a milder phenotype responsive to riboflavin were shown to have single amino acid changes in the FADS domain. When produced in E. coli, these mutant FADS proteins resulted in impaired but detectable FADS activity; for one of the variant proteins, the addition of FAD significantly improved protein stability, arguing for a chaperone-like action similar to what has been reported in other riboflavin-responsive inborn errors of metabolism. In conclusion, our studies identify FLAD1 variants as a cause of potentially treatable inborn errors of metabolism manifesting with MADD and shed light on the mechanisms by which FADS ensures cellular FAD homeostasis. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

DNA methylation perturbations in genes involved in polyunsaturated Fatty Acid biosynthesis associated with depression and suicide risk.

PubMed

Haghighi, Fatemeh; Galfalvy, Hanga; Chen, Sean; Huang, Yung-Yu; Cooper, Thomas B; Burke, Ainsley K; Oquendo, Maria A; Mann, J John; Sublette, M Elizabeth

2015-01-01

Polyunsaturated fatty acid (PUFA) status has been associated with neuropsychiatric disorders, including depression and risk of suicide. Long-chain PUFAs (LC-PUFAs) are obtained in the diet or produced by sequential desaturation and elongation of shorter-chain precursor fatty acids linoleic acid (LA, 18:2n-6) and α-linolenic acid (ALA, 18:3n-3). We compared DNA methylation patterns in genes involved in LC-PUFA biosynthesis in major depressive disorder (MDD) with (n = 22) and without (n = 39) history of suicide attempt, and age- and sex-matched healthy volunteers (n = 59). Plasma levels of selected PUFAs along the LC-PUFA biosynthesis pathway were determined by transesterification and gas chromatography. CpG methylation levels for the main human LC-PUFA biosynthetic genes, fatty acid desaturases 1 (Fads1) and 2 (Fads2), and elongation of very long-chain fatty acids protein 5 (Elovl5), were assayed by bisulfite pyrosequencing. Associations between PUFA levels and diagnosis or suicide attempt status did not survive correction for multiple testing. However, MDD diagnosis and suicide attempts were significantly associated with DNA methylation in Elovl5 gene regulatory regions. Also the relative roles of PUFA levels and DNA methylation with respect to diagnostic and suicide attempt status were determined by least absolute shrinkage and selection operator logistic regression analyses. We found that PUFA associations with suicide attempt status were explained by effects of Elovl5 DNA methylation within the regulatory regions. The observed link between plasma PUFA levels, DNA methylation, and suicide risk may have implications for modulation of disease-associated epigenetic marks by nutritional intervention.

Transcriptional Activation of Two Delta-9 Palmitoyl-ACP Desaturase Genes by MYB115 and MYB118 Is Critical for Biosynthesis of Omega-7 Monounsaturated Fatty Acids in the Endosperm of Arabidopsis Seeds

PubMed Central

Troncoso-Ponce, Manuel Adrián; Barthole, Guillaume; Tremblais, Geoffrey

2016-01-01

In angiosperms, double fertilization of the embryo sac initiates the development of the embryo and the endosperm. In Arabidopsis thaliana, an exalbuminous species, the endosperm is reduced to one cell layer during seed maturation and reserves such as oil are massively deposited in the enlarging embryo. Here, we consider the strikingly different fatty acid (FA) compositions of the oils stored in the two zygotic tissues. Endosperm oil is enriched in ω-7 monounsaturated FAs, that represent more than 20 mol% of total FAs, whereas these molecular species are 10-fold less abundant in the embryo. Two closely related transcription factors, MYB118 and MYB115, are transcriptionally induced at the onset of the maturation phase in the endosperm and share a set of transcriptional targets. Interestingly, the endosperm oil of myb115 myb118 double mutants lacks ω-7 FAs. The identification of two Δ9 palmitoyl-ACP desaturases responsible for ω-7 FA biosynthesis, which are activated by MYB115 and MYB118 in the endosperm, allows us to propose a model for the transcriptional control of oil FA composition in this tissue. In addition, an initial characterization of the structure-function relationship for these desaturases reveals that their particular substrate specificity is conferred by amino acid residues lining their substrate pocket that distinguish them from the archetype Δ9 stearoyl-ACP desaturase. PMID:27681170

Mechanism and regulation of mycobactin fatty acyl-AMP ligase FadD33.

PubMed

Vergnolle, Olivia; Xu, Hua; Blanchard, John S

2013-09-27

Mycobacterial siderophores are critical components for bacterial virulence in the host. Pathogenic mycobacteria synthesize iron chelating siderophores named mycobactin and carboxymycobactin to extract intracellular macrophage iron. The two siderophores differ in structure only by a lipophilic aliphatic chain attached on the ε-amino group of the lysine mycobactin core, which is transferred by MbtK. Prior to acyl chain transfer, the lipophilic chain requires activation by a specific fatty acyl-AMP ligase FadD33 (also known as MbtM) and is then loaded onto phosphopantetheinylated acyl carrier protein (holo-MbtL) to form covalently acylated MbtL. We demonstrate that FadD33 prefers long chain saturated lipids and initial velocity studies showed that FadD33 proceeds via a Bi Uni Uni Bi ping-pong mechanism. Inhibition experiments suggest that, during the first half-reaction (adenylation), fatty acid binds first to the free enzyme, followed by ATP and the release of pyrophosphate to form the adenylate intermediate. During the second half-reaction (ligation), holo-MbtL binds to the enzyme followed by the release of products AMP and acylated MbtL. In addition, we characterized a post-translational regulation mechanism of FadD33 by the mycobacterial protein lysine acetyltransferase in a cAMP-dependent manner. FadD33 acetylation leads to enzyme inhibition, which can be reversed by the NAD(+)-dependent deacetylase, MSMEG_5175 (DAc1). To the best of our knowledge, this is the first time that bacterial siderophore synthesis has been shown to be regulated via post-translational protein acetylation.

Bioengineering resistance to phytoene desaturase inhibitors in Arabidopsis thaliana

USDA-ARS?s Scientific Manuscript database

Three natural somatic mutations at codon 304 of the phytoene desaturase gene (pds) of Hydrilla verticillata ( L. f. Royle) have been reported to provide resistance to the herbicide fluridone. We substituted the arginine 304 present in the wild-type H. verticillata phytoene desaturase (PDS) with all...

Establishment of a hepatocyte line for studying biosynthesis of long-chain polyunsaturated fatty acids from a marine teleost, the white-spotted spinefoot Siganus canaliculatus.

PubMed

Liu, Y; Zhang, Q H; Dong, Y W; You, C H; Wang, S Q; Li, Y Q; Li, Y Y

2017-08-01

A hepatocyte line was established from the liver of white-spotted spinefoot Siganus canaliculatus to study the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFA). The cells from the line, designated S. canaliculatus hepatocyte line (SCHL), grew and multiplied well in Dulbecco's modified Eagle's medium (DMEM)-F12 medium supplemented with 20 mM 4-(2-hydroxyethyl) piperazine-1-ethanesulphonic acid (HEPES), 10% foetal bovine serum (FBS) and 0·5% rainbow trout Oncorhychus mykiss serum at 28° C, showing an epithelial-like morphology and the normal chromosome number of 48 (2n) and have been subcultured for over 60 passages. The identity of the hepatocytes was confirmed by periodic acid Schiff (PAS) staining. The mRNA expression of all genes encoding the key enzymes for LC-PUFA biosynthesis including two desaturases (Δ4 Fad and Δ6-Δ5 Fad) and two elongases (Elovl4 and Elovl5), were detected in all cells from passages 5 to 60 and their expression levels became stable after passage 35 and showed responses to various PUFA incubation. This is similar to the situation determined in the liver of S. canaliculatus that were fed diets containing different fatty acids. These results indicated that SCHL was successfully established and can provide an in vitro tool to investigate lipid metabolism and regulatory mechanisms of LC-PUFA biosynthesis in teleosts, especially marine species. © 2017 The Fisheries Society of the British Isles.

Stearoyl-Acyl Carrier Protein Desaturase Mutations Uncover an Impact of Stearic Acid in Leaf and Nodule Structure.

PubMed

Lakhssassi, Naoufal; Colantonio, Vincent; Flowers, Nicholas D; Zhou, Zhou; Henry, Jason; Liu, Shiming; Meksem, Khalid

2017-07-01

Stearoyl-acyl carrier protein desaturase (SACPD-C) has been reported to control the accumulation of seed stearic acid; however, no study has previously reported its involvement in leaf stearic acid content and impact on leaf structure and morphology. A subset of an ethyl methanesulfonate mutagenized population of soybean ( Glycine max ) 'Forrest' was screened to identify mutants within the GmSACPD-C gene. Using a forward genetics approach, one nonsense and four missense Gmsacpd-c mutants were identified to have high levels of seed, nodule, and leaf stearic acid content. Homology modeling and in silico analysis of the GmSACPD-C enzyme revealed that most of these mutations were localized near or at conserved residues essential for diiron ion coordination. Soybeans carrying Gmsacpd-c mutations at conserved residues showed the highest stearic acid content, and these mutations were found to have deleterious effects on nodule development and function. Interestingly, mutations at nonconserved residues show an increase in stearic acid content yet retain healthy nodules. Thus, random mutagenesis and mutational analysis allows for the achievement of high seed stearic acid content with no associated negative agronomic characteristics. Additionally, expression analysis demonstrates that nodule leghemoglobin transcripts were significantly more abundant in soybeans with deleterious mutations at conserved residues of GmSACPD-C. Finally, we report that Gmsacpd-c mutations cause an increase in leaf stearic acid content and an alteration of leaf structure and morphology in addition to differences in nitrogen-fixing nodule structure. © 2017 American Society of Plant Biologists. All Rights Reserved.

Computational analysis of a novel mutation in ETFDH gene highlights its long-range effects on the FAD-binding motif.

PubMed

Er, Tze-Kiong; Chen, Chih-Chieh; Liu, Yen-Yi; Chang, Hui-Chiu; Chien, Yin-Hsiu; Chang, Jan-Gowth; Hwang, Jenn-Kang; Jong, Yuh-Jyh

2011-10-21

Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is an autosomal recessive disease caused by the defects in the mitochondrial electron transfer system and the metabolism of fatty acids. Recently, mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene, encoding electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) have been reported to be the major causes of riboflavin-responsive MADD. To date, no studies have been performed to explore the functional impact of these mutations or their mechanism of disrupting enzyme activity. High resolution melting (HRM) analysis and sequencing of the entire ETFDH gene revealed a novel mutation (p.Phe128Ser) and the hotspot mutation (p.Ala84Thr) from a patient with MADD. According to the predicted 3D structure of ETF:QO, the two mutations are located within the flavin adenine dinucleotide (FAD) binding domain; however, the two residues do not have direct interactions with the FAD ligand. Using molecular dynamics (MD) simulations and normal mode analysis (NMA), we found that the p.Ala84Thr and p.Phe128Ser mutations are most likely to alter the protein structure near the FAD binding site as well as disrupt the stability of the FAD binding required for the activation of ETF:QO. Intriguingly, NMA revealed that several reported disease-causing mutations in the ETF:QO protein show highly correlated motions with the FAD-binding site. Based on the present findings, we conclude that the changes made to the amino acids in ETF:QO are likely to influence the FAD-binding stability.

Computational analysis of a novel mutation in ETFDH gene highlights its long-range effects on the FAD-binding motif

PubMed Central

2011-01-01

Background Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is an autosomal recessive disease caused by the defects in the mitochondrial electron transfer system and the metabolism of fatty acids. Recently, mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene, encoding electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) have been reported to be the major causes of riboflavin-responsive MADD. To date, no studies have been performed to explore the functional impact of these mutations or their mechanism of disrupting enzyme activity. Results High resolution melting (HRM) analysis and sequencing of the entire ETFDH gene revealed a novel mutation (p.Phe128Ser) and the hotspot mutation (p.Ala84Thr) from a patient with MADD. According to the predicted 3D structure of ETF:QO, the two mutations are located within the flavin adenine dinucleotide (FAD) binding domain; however, the two residues do not have direct interactions with the FAD ligand. Using molecular dynamics (MD) simulations and normal mode analysis (NMA), we found that the p.Ala84Thr and p.Phe128Ser mutations are most likely to alter the protein structure near the FAD binding site as well as disrupt the stability of the FAD binding required for the activation of ETF:QO. Intriguingly, NMA revealed that several reported disease-causing mutations in the ETF:QO protein show highly correlated motions with the FAD-binding site. Conclusions Based on the present findings, we conclude that the changes made to the amino acids in ETF:QO are likely to influence the FAD-binding stability. PMID:22013910

Hepatic delta 6-desaturase activity in lean and genetically obese ob/ob mice.

PubMed Central

Hughes, S; York, D A

1985-01-01

Hepatic delta 6-desaturase activity is primarily located in the mitochondrial fraction in mice. Both delta 6- and delta 5-desaturase activities are increased in the liver of young (6-week-old) obese mice. The increase in hepatic delta 6-desaturase activity in obese mice does not occur until weaning. Neither restriction of food intake nor hyperinsulinaemia normalize hepatic delta 6-desaturase activity of obese mice. Both cold acclimation and tri-iodothyronine (30 micrograms/day per kg) decreased hepatic delta 6-desaturase activity of obese mice to levels observed in lean mice, whereas the increase in activity in obese mice was still maintained after the induction of hypothyroidism. PMID:3977836

Facebook Addiction Disorder (FAD) among German students—A longitudinal approach

PubMed Central

Margraf, Jürgen

2017-01-01

The present study aimed to investigate Facebook Addiction Disorder (FAD) in a German student sample over a period of one year. While mean FAD level did not increase during the investigation period, a significant increase was shown in the number of participants reaching the critical cutoff score. FAD was significantly positively related to the personality trait narcissism and to negative mental health variables (depression, anxiety, and stress symptoms). Furthermore, FAD fully mediated the significant positive relationship between narcissism and stress symptoms, which demonstrates that narcissistic people can be specifically at risk to develop FAD. Present results give a first overview of FAD in Germany. Practical applications for future studies and limitations of present results are discussed. PMID:29240823

Facebook Addiction Disorder (FAD) among German students-A longitudinal approach.

PubMed

Brailovskaia, Julia; Margraf, Jürgen

2017-01-01

The present study aimed to investigate Facebook Addiction Disorder (FAD) in a German student sample over a period of one year. While mean FAD level did not increase during the investigation period, a significant increase was shown in the number of participants reaching the critical cutoff score. FAD was significantly positively related to the personality trait narcissism and to negative mental health variables (depression, anxiety, and stress symptoms). Furthermore, FAD fully mediated the significant positive relationship between narcissism and stress symptoms, which demonstrates that narcissistic people can be specifically at risk to develop FAD. Present results give a first overview of FAD in Germany. Practical applications for future studies and limitations of present results are discussed.

Inverse Flush Air Data System (FADS) for Real Time Simulations

NASA Astrophysics Data System (ADS)

Madhavanpillai, Jayakumar; Dhoaya, Jayanta; Balakrishnan, Vidya Saraswathi; Narayanan, Remesh; Chacko, Finitha Kallely; Narayanan, Shyam Mohan

2017-12-01

Flush Air Data Sensing System (FADS) forms a mission critical sub system in future reentry vehicles. FADS makes use of surface pressure measurements from the nose cap of the vehicle for deriving the air data parameters of the vehicle such as angle of attack, angle of sideslip, Mach number, etc. These parameters find use in the flight control and guidance systems, and also assist in the overall mission management. The FADS under consideration in this paper makes use of nine pressure ports located in the nose cap of a technology demonstrator vehicle. In flight, the air data parameters are obtained from the FADS estimation algorithm using the pressure data at the nine pressure ports. But, these pressure data will not be available, for testing the FADS package during ground simulation. So, an inverse software to FADS which estimates the pressure data at the pressure ports for a given flight condition is developed. These pressure data at the nine ports will go as input to the FADS package during ground simulation. The software is run to generate the pressure data for the descent phase trajectory of the technology demonstrator. This data is used again to generate the air data parameters from FADS algorithm. The computed results from FADS algorithm match well with the trajectory data.

Elevated stearoyl-CoA desaturase-1 expression in skeletal muscle contributes to abnormal fatty acid partitioning in obese humans

PubMed Central

Hulver, Matthew W.; Berggren, Jason R.; Carper, Michael J.; Miyazaki, Makoto; Ntambi, James M.; Hoffman, Eric P.; Thyfault, John P.; Stevens, Robert; Dohm, G. Lynis; Houmard, Joseph A.; Muoio, Deborah M.

2014-01-01

Summary Obesity and type 2 diabetes are strongly associated with abnormal lipid metabolism and accumulation of intramyocellular triacylglycerol, but the underlying cause of these perturbations are yet unknown. Herein, we show that the lipogenic gene, stearoyl-CoA desaturase 1 (SCD1), is robustly up-regulated in skeletal muscle from extremely obese humans. High expression and activity of SCD1, an enzyme that catalyzes the synthesis of monounsaturated fatty acids, corresponded with low rates of fatty acid oxidation, increased triacylglycerol synthesis and increased monounsaturation of muscle lipids. Elevated SCD1 expression and abnormal lipid partitioning were retained in primary skeletal myocytes derived from obese compared to lean donors, implying that these traits might be driven by epigenetic and/or heritable mechanisms. Overexpression of human SCD1 in myotubes from lean subjects was sufficient to mimic the obese phenotype. These results suggest that elevated expression of SCD1 in skeletal muscle contributes to abnormal lipid metabolism and progression of obesity. PMID:16213227

Elevated stearoyl-CoA desaturase-1 expression in skeletal muscle contributes to abnormal fatty acid partitioning in obese humans.

PubMed

Hulver, Matthew W; Berggren, Jason R; Carper, Michael J; Miyazaki, Makoto; Ntambi, James M; Hoffman, Eric P; Thyfault, John P; Stevens, Robert; Dohm, G Lynis; Houmard, Joseph A; Muoio, Deborah M

2005-10-01

Obesity and type 2 diabetes are strongly associated with abnormal lipid metabolism and accumulation of intramyocellular triacylglycerol, but the underlying cause of these perturbations are yet unknown. Herein, we show that the lipogenic gene, stearoyl-CoA desaturase 1 (SCD1), is robustly up-regulated in skeletal muscle from extremely obese humans. High expression and activity of SCD1, an enzyme that catalyzes the synthesis of monounsaturated fatty acids, corresponded with low rates of fatty acid oxidation, increased triacylglycerol synthesis and increased monounsaturation of muscle lipids. Elevated SCD1 expression and abnormal lipid partitioning were retained in primary skeletal myocytes derived from obese compared to lean donors, implying that these traits might be driven by epigenetic and/or heritable mechanisms. Overexpression of human SCD1 in myotubes from lean subjects was sufficient to mimic the obese phenotype. These results suggest that elevated expression of SCD1 in skeletal muscle contributes to abnormal lipid metabolism and progression of obesity.

Setting the Record Straight. The Truth About Fad Diets.

ERIC Educational Resources Information Center

Wheat Foods Council, Parker, CO.

The Setting the Record Straight information packet presents facts to set the record straight about nutrition and debunk fad diets. The kit features materials designed to communicate the importance of balanced eating. Materials include: a time line of fad diets; four reproducible fad diet book review handouts that show the misleading claims rampant…

Prediction of FAD binding sites in electron transport proteins according to efficient radial basis function networks and significant amino acid pairs.

PubMed

Le, Nguyen-Quoc-Khanh; Ou, Yu-Yen

2016-07-30

Cellular respiration is a catabolic pathway for producing adenosine triphosphate (ATP) and is the most efficient process through which cells harvest energy from consumed food. When cells undergo cellular respiration, they require a pathway to keep and transfer electrons (i.e., the electron transport chain). Due to oxidation-reduction reactions, the electron transport chain produces a transmembrane proton electrochemical gradient. In case protons flow back through this membrane, this mechanical energy is converted into chemical energy by ATP synthase. The convert process is involved in producing ATP which provides energy in a lot of cellular processes. In the electron transport chain process, flavin adenine dinucleotide (FAD) is one of the most vital molecules for carrying and transferring electrons. Therefore, predicting FAD binding sites in the electron transport chain is vital for helping biologists understand the electron transport chain process and energy production in cells. We used an independent data set to evaluate the performance of the proposed method, which had an accuracy of 69.84 %. We compared the performance of the proposed method in analyzing two newly discovered electron transport protein sequences with that of the general FAD binding predictor presented by Mishra and Raghava and determined that the accuracy of the proposed method improved by 9-45 % and its Matthew's correlation coefficient was 0.14-0.5. Furthermore, the proposed method enabled reducing the number of false positives significantly and can provide useful information for biologists. We developed a method that is based on PSSM profiles and SAAPs for identifying FAD binding sites in newly discovered electron transport protein sequences. This approach achieved a significant improvement after we added SAAPs to PSSM features to analyze FAD binding proteins in the electron transport chain. The proposed method can serve as an effective tool for predicting FAD binding sites in electron

Influence of oilseed supplement ranging in n-6/n-3 ratio on fatty acid composition and Δ5-, Δ6-desaturase protein expression in steer muscles.

PubMed

Turner, T D; Mitchell, A; Duynisveld, J; Pickova, J; Doran, O; McNiven, M A

2012-12-01

This study investigated effects of roasted or extruded oilseed supplementation ranging in n-6/n-3 ratios from 0.3 to 5.0 on the fatty acid composition and expression of delta-5 desaturase (Δ5d) and Δ6-desaturase (Δ6d) protein in commercial steer cheek (m. masseter) and diaphragm (pars costalis diaphragmatis) muscles. In general, the n-6/n-3 ratio of the diet had a subsequent effect on the muscle n-6/n-3 ratio (P < 0.05), with muscle 18:2n-6 and 18:3n-3 content relating to proportion of dietary soya bean and linseed (P < 0.01). Compared with canola, pure linseed and soya bean diets reduced 14:1c-9 and 16:1c-9 (P < 0.05) but increased 18:1t-11 and c-9,t-11 conjugated linoleic acid (CLA) content (P < 0.01). Oilseed processing had a minor influence but extruded oilseeds increase 18:1t-11 and c-9,t-11 CLA compared with roasted (P < 0.05). Polar lipid 18:3n-3 and n-3 long-chain polyunsaturated fatty acid (LC, ⩾20 carbons PUFA) derivative content increased in relation to dietary linseed supplementation in the diaphragm (P < 0.01), whereas only 18:3n-3 was increased in the cheek (P < 0.01). Protein expression did not differ between diets; however, in each muscle the Δ5d protein expression had a stronger association with the desaturase products rather than the precursors. The relationship between Δ5d protein expression and the muscle LC n-6/n-3 ratio was negative in both muscles (P < 0.05). The relationship between Δ6d protein expression and the LC n-6/n-3 ratio was positive in the cheek (P < 0.001) and negative in the diaphragm (P < 0.05). In conclusion, diet n-6/n-3 ratio affected muscle 18:2n-6 and 18:3n-3 deposition, whereas the Δ5d and Δ6d protein expression had some influence on the polar lipid LC-PUFA profile. Results reaffirm that processed oilseeds can be used to increase the proportion of fatty acids potentially beneficial for human health, by influencing the formation of LC-PUFA and reducing the n-6/n-3 ratio.

The prokaryotic FAD synthetase family: a potential drug target.

PubMed

Serrano, Ana; Ferreira, Patricia; Martínez-Júlvez, Marta; Medina, Milagros

2013-01-01

Disruption of cellular production of the flavin cofactors, flavin adenine mononucleotide (FMN) and flavin adenine dinucleotide(FAD) will prevent the assembly of a large number of flavoproteins and flavoenzymes involved in key metabolic processes in all types of organisms. The enzymes responsible for FMN and FAD production in prokaryotes and eukaryotes exhibit various structural characteristics to catalyze the same chemistry, a fact that converts the prokaryotic FAD synthetase (FADS) in a potential drug target for the development of inhibitors endowed with anti-pathogenic activity. The first step before searching for selective inhibitors of FADS is to understand the structural and functional mechanisms for the riboflavin kinase and FMN adenylyltransferase activities of the prokaryotic enzyme, and particularly to identify their differential functional characteristics with regard to the enzymes performing similar functions in other organisms, particularly humans. In this paper, an overview of the current knowledge of the structure-function relationships in prokaryotic FADS has been presented, as well as of the state of the art in the use of these enzymes as drug targets.

Temporal and tissue-specific regulation of a Brassica napus stearoyl-acyl carrier protein desaturase gene.

PubMed Central

Slocombe, S P; Piffanelli, P; Fairbairn, D; Bowra, S; Hatzopoulos, P; Tsiantis, M; Murphy, D J

1994-01-01

The nucleotide sequence of a Brassica napus stearoyl-acyl carrier protein desaturase gene (Bn10) is presented. This gene is one member of a family of four closely related genes expressed in oilseed rape. The expression of the promoter of this gene in transgenic tobacco was found to be temporally regulated in the developing seed tissues. However, the promoter was also particularly active in other oleogenic tissues such as the tapetum and pollen grains. This raises the interesting question of whether seed-expressed lipid synthesis genes are regulated by separate tissue-specific determinants or by a single factor common to all oleogenic tissues. Parts of the plants undergoing rapid development such as the components of immature flowers and seedlings also exhibited high levels of promoter activity. These tissues are likely to have an elevated requirement for membrane lipid synthesis. Stearoyl-acyl carrier protein desaturase transcript levels have previously been shown to be temporally regulated in the B. napus embryo (S.P. Slocombe, I. Cummins, R.P. Jarvis, D.J. Murphy [1992] Plant Mol Biol 20: 151-155). Evidence is presented demonstrating the induction of desaturase mRNA by abscisic acid in the embryo. PMID:8016261

A Transgenic Camelina sativa Seed Oil Effectively Replaces Fish Oil as a Dietary Source of Eicosapentaenoic Acid in Mice123

PubMed Central

Tejera, Noemi; Vauzour, David; Betancor, Monica B; Sayanova, Olga; Usher, Sarah; Cochard, Marianne; Rigby, Neil; Ruiz-Lopez, Noemi; Menoyo, David; Tocher, Douglas R; Napier, Johnathan A; Minihane, Anne Marie

2016-01-01

Background: Fish currently supplies only 40% of the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) required to allow all individuals globally to meet the minimum intake recommendation of 500 mg/d. Therefore, alternative sustainable sources are needed. Objective: The main objective was to investigate the ability of genetically engineered Camelina sativa (20% EPA) oil (CO) to enrich tissue EPA and DHA relative to an EPA-rich fish oil (FO) in mammals. Methods: Six-week-old male C57BL/6J mice were fed for 10 wk either a palm oil–containing control (C) diet or diets supplemented with EPA-CO or FO, with the C, low-EPA CO (COL), high-EPA CO (COH), low-EPA FO (FOL), and high-EPA FO (FOH) diets providing 0, 0.4, 3.4, 0.3, and 2.9 g EPA/kg diet, respectively. Liver, muscle, and brain were collected for fatty acid analysis, and blood glucose and serum lipids were quantified. The expression of selected hepatic genes involved in EPA and DHA biosynthesis and in modulating their cellular impact was determined. Results: The oils were well tolerated, with significantly greater weight gain in the COH and FOH groups relative to the C group (P < 0.001). Significantly lower (36–38%) blood glucose concentrations were evident in the FOH and COH mice relative to C mice (P < 0.01). Hepatic EPA concentrations were higher in all EPA groups relative to the C group (P < 0.001), with concentrations of 0.0, 0.4, 2.9, 0.2, and 3.6 g/100 g liver total lipids in the C, COL, COH, FOL, and FOH groups, respectively. Comparable dose-independent enrichments of liver DHA were observed in mice fed CO and FO diets (P < 0.001). Relative to the C group, lower fatty acid desaturase 1 (Fads1) expression (P < 0.005) was observed in the COH and FOH groups. Higher fatty acid desaturase 2 (Fads2), peroxisome proliferator–activated receptor α (Ppara), and peroxisome proliferator–activated receptor γ (Pparg) (P < 0.005) expressions were induced by CO. No impact of treatment on liver X receptor

Half-of-the-Sites Reactivity of the Castor Δ9-18:0-Acyl Carrier Protein Desaturase1[OPEN

PubMed Central

Liu, Qin; Chai, Jin; Moche, Martin; Guy, Jodie; Lindqvist, Ylva; Shanklin, John

2015-01-01

Fatty acid desaturases regulate the unsaturation status of cellular lipids. They comprise two distinct evolutionary lineages, a soluble class found in the plastids of higher plants and an integral membrane class found in plants, yeast (Saccharomyces cerevisiae), animals, and bacteria. Both classes exhibit a dimeric quaternary structure. Here, we test the functional significance of dimeric organization of the soluble castor Δ9-18:0-acyl carrier protein desaturase, specifically, the hypothesis that the enzyme uses an alternating subunit half-of-the-sites reactivity mechanism whereby substrate binding to one subunit is coordinated with product release from the other subunit. Using a fluorescence resonance energy transfer assay, we demonstrated that dimers stably associate at concentrations typical of desaturase assays. An active site mutant T104K/S202E, designed to occlude the substrate binding cavity, was expressed, purified, and its properties validated by x-ray crystallography, size exclusion chromatography, and activity assay. Heterodimers comprising distinctly tagged wild-type and inactive mutant subunits were purified at 1:1 stoichiometry. Despite having only one-half the number of active sites, purified heterodimers exhibit equivalent activity to wild-type homodimers, consistent with half-of-the-sites reactivity. However, because multiple rounds of turnover were observed, we conclude that substrate binding to one subunit is not required to facilitate product release from the second subunit. The observed half-of-the-sites reactivity could potentially buffer desaturase activity from oxidative inactivation. That soluble desaturases require only one active subunit per dimer for full activity represents a mechanistic difference from the membrane class of desaturases such as the Δ9-acyl-CoA, Ole1p, from yeast, which requires two catalytically competent subunits for activity. PMID:26224800

Stearoyl-CoA desaturase activity is elevated by the suppression of its degradation by clofibric acid in the liver of rats.

PubMed

Toyama, Tomoaki; Kudo, Naomi; Mitsumoto, Atsushi; Hibino, Yasuhide; Tsuda, Tadashi; Kawashima, Yoichi

2007-04-01

A mechanism by which fibrates control stearoyl-CoA desaturase (SCD) in the liver was studied. Treatment of rats with 2-(4-chlorophenoxy)-2-methylpropionic acid (clofibric acid) or feeding of a fat-free diet markedly elevated hepatic activity of SCD. Both the treatment with clofibric acid and the feeding of the fat-free diet caused an increase in the steady-state level of SCD1 mRNA and enhanced transcriptional rate. The half-lives of SCD for control rats, rats treated with clofibric acid rats, and rats fed the fat-free diet were estimated to be 2.0, 3.9, and 1.9 h, respectively. Activity of palmitoyl-CoA chain elongase (PCE) was increased by both clofibric acid treatment and feeding of the fat-free diet as was observed with SCD. Steady-state level of rat fatty acid elongase 2 mRNA was increased by the treatment with clofibric acid or feeding of fat-free diet, although the transcriptional rate was not altered. Different from SCD, PCE was highly stable and its half-life was not changed by either clofibric acid or fat-free diet. These results strongly suggest that the decreased degradation of SCD is responsible for the increase in its activity in addition to increased transcription of SCD1 in the rats treated with clofibric acid.

Perfluorodecanoic acid enhances the formation of oleic acid in rat liver.

PubMed Central

Yamamoto, A; Kawashima, Y

1997-01-01

The feeding of perfluorodecanoic acid (PFDA) to male rats at a dietary concentration of 0.005% (w/w) for 7 days resulted in a marked increase in the activity of microsomal stearoyl-CoA desaturation in the liver. This increase in the overall desaturation activity was due to the induction of terminal desaturase among the components comprising the desaturation system. In contrast, PFDA inhibited desaturation in vitro, seemingly due to interference with electron transport through the desaturation system. Accordingly, PFDA can be an inducer and also an inhibitor of delta9-desaturation. PFDA feeding enhanced the conversion of radioactive stearic acid into oleic acid in the liver in vivo, indicating that the induction of delta9-desaturase by PFDA functions in vivo. PFDA feeding increased the mass of octadecenoic acid (C18:1) in the liver and the proportion of C18:1 in microsomal lipid. A highly significant linear correlation existed between the microsomal desaturase activity and the proportion of C18:1 in microsomal lipid when compared using rats in five different physiological states: control, PFDA-fed, p-chlorophenoxyisobutyric acid (clofibric acid)-fed, starved and starved/refed. These results suggest that the increase in the hepatic level of C18:1 caused by feeding of PFDA to rats can be explained by the common concept of regulation, i.e. the hepatic level of C18:1 is under the control of delta9-desaturase. The dietary administration of PFDA also increased the content of cytochrome P-450 and the activity of 7-ethoxycoumarin O-de-ethylase in the liver. PMID:9230124

Lipopolysaccharide derived from the rumen down-regulates stearoyl-CoA desaturase 1 expression and alters fatty acid composition in the liver of dairy cows fed a high-concentrate diet.

PubMed

Xu, Tianle; Tao, Hui; Chang, Guangjun; Zhang, Kai; Xu, Lei; Shen, Xiangzhen

2015-03-07

Dairy cows are often fed a high-concentrate diet to meet lactating demands, yet long-term concentrate feeding induces subacute ruminal acidosis (SARA) and leads to a decrease in milk fat. Stearoyl-CoA desaturase1 (SCD1) participates in fatty acid biosynthesis in the liver of lactating ruminants. Here, we conducted this study to investigate the impact of lipopolysaccharide derived from the rumen on SCD1 expression and on fatty acid composition in the liver of dairy cows fed a high-concentrate diet. Eight multiparous mid-lactating Holstein cows (455 ± 28 kg) were randomly assigned into two groups in the experiment and were fed a low-concentrate diet (LC) or high-concentrate diet (HC) for 18 weeks. The results showed that the total volatile fatty acids and lactic acid accumulated in the rumen, leading to a decreased rumen pH and elevated lipopolysaccharides (LPSs) in the HC group. The long chain fatty acid profile in the rumen and hepatic vein was remarkably altered in the animals fed the HC diet. The triglyceride (TG), non-esterified fatty acid (NEFA) and total cholesterol (TCH) content in the plasma was significantly decreased, whereas plasma glucose and insulin levels were increased. The expression of SCD1 in the liver was significantly down-regulated in the HC group. In regards to transcriptional regulators, the expression of sterol regulatory element binding transcription factors (SREBF1c, SREBF2) and SREBP cleavage activating protein (SCAP) was down-regulated, while peroxisome proliferator-activated receptor α (PPARα) was up-regulated. These data indicate that lipopolysaccharide derived from the rumen down-regulates stearoyl-CoA desaturase 1 expression and alters fatty acid composition in the liver of dairy cows fed a high-concentrate diet.

Application of the FADS system on the Re-entry Module

NASA Astrophysics Data System (ADS)

Zhen, Huang

2016-07-01

The aerodynamic model for Flush Air Data Sensing System (FADS) is built based on the surface pressure distribution obtained through the pressure orifices laid on specific positions of the surface,and the flight parameters,such as angle of attack,angle of side-slip,Mach number,free-stream static pressure and dynamic pressure are inferred from the aerodynamic model.The flush air data sensing system (FADS) has been used on several flight tests of aircraft and re-entry vehicle,such as,X-15,space shuttle,F-14,X-33,X-43A and so on. This paper discusses the application of the FADS on the re-entry module with blunt body to obtain high-precision aerodynamic parameters.First of all,a basic theory and operating principle of the FADS is shown.Then,the applications of the FADS on typical aircrafts and re-entry vehicles are described.Thirdly,the application mode on the re-entry module with blunt body is discussed in detail,including aerodynamic simulation,pressure distribution,trajectory reconstruction and the hardware shoule be used,such as flush air data sensing system(FADS),inertial navigation system (INS),data acquisition system,data storage system.Finally,ablunt module re-entry flight test from low earth orbit (LEO) is planned to obtain aerodynamic parameters and amend the aerodynamic model with this FADS system data.The results show that FADS system can be applied widely in re-entry module with blunt bodies.

Inactivated and live bivalent fowl adenovirus (FAdV8b + FAdV11) breeder vaccines provide broad-spectrum protection in chicks against inclusion body hepatitis (IBH).

PubMed

Gupta, Ashish; Popowich, Shelly; Ojkic, Davor; Kurukulasuriya, Shanika; Chow-Lockerbie, Betty; Gunawardana, Thushari; Goonewardene, Kalhari; Karunarathna, Ruwani; Ayalew, Lisanework E; Ahmed, Khawaja Ashfaque; Tikoo, Suresh K; Willson, Philip; Gomis, Susantha

2018-01-29

Fowl adenovirus (FAdV) is comprised of five species (A to E) and 12 serotypes (1-7, 8a, 8b, 9-11). Inclusion body hepatitis (IBH) is caused by FAdV-7, 8a, 8b (species E) and FAdV-2 and 11 (species D). Commercial vaccines against IBH are not available in Canada. Autogenous FAdV broiler breeder vaccines are now used in some areas where outbreaks of IBH are occurring. The objective of this study was to evaluate the efficacy of a bivalent (species D and E) live and an inactivated FAdV broiler breeder vaccine in protecting broiler chicks against IBH through maternal antibody (MtAb) transfer. FAdV seronegative broiler breeders (n = 300/group) received either a live or inactivated bivalent (FAdV-8b-SK + FAdV-11-1047) vaccine. The live vaccine (1 × 10 4 TCID 50 of each virus/bird) was given orally once at 16 weeks of age and the inactivated vaccine (1 × 10 6 TCID 50 of each virus + 20% Emulsigen D) was given intramuscularly at 16 and 19 weeks of age. Controls (n = 150) were given saline orally. The inactivated vaccine group was boosted 3 weeks later with the same vaccine. Neutralizing antibodies (NAb) in sera (n = 10) were detected at 19, 22, 30 and 48 weeks of age. NAb were able to neutralize various FAdV serotypes within species D and E. Mean NAb were similar in the both live and killed vaccine groups at 19, 30 and 48 weeks and ranged from 2.4 to 3.7 log 10 . Approximately 26 ± 7% of MtAbs were passively transferred through eggs to day-old chicks. Progeny challenged with a lethal dose (1 × 10 7 TCID 50 /bird intramuscularly) of FAdV-8b-SK, FAdV-11-1047, or FAdV-2-685 (n = 90/group) at 14 days post-hatch (dph) showed 98-100% protection in broiler chicks to homologous or heterologous FAdV challenges. Our data suggests that a bivalent live and an inactivated FAdV vaccine are equally effective and have the potential for the control of IBH. Copyright © 2017 Elsevier Ltd. All rights reserved.

FAD Regulates CRYPTOCHROME Protein Stability and Circadian Clock in Mice.

PubMed

Hirano, Arisa; Braas, Daniel; Fu, Ying-Hui; Ptáček, Louis J

2017-04-11

The circadian clock generates biological rhythms of metabolic and physiological processes, including the sleep-wake cycle. We previously identified a missense mutation in the flavin adenine dinucleotide (FAD) binding pocket of CRYPTOCHROME2 (CRY2), a clock protein that causes human advanced sleep phase. This prompted us to examine the role of FAD as a mediator of the clock and metabolism. FAD stabilized CRY proteins, leading to increased protein levels. In contrast, knockdown of Riboflavin kinase (Rfk), an FAD biosynthetic enzyme, enhanced CRY degradation. RFK protein levels and FAD concentrations oscillate in the nucleus, suggesting that they are subject to circadian control. Knockdown of Rfk combined with a riboflavin-deficient diet altered the CRY levels in mouse liver and the expression profiles of clock and clock-controlled genes (especially those related to metabolism including glucose homeostasis). We conclude that light-independent mechanisms of FAD regulate CRY and contribute to proper circadian oscillation of metabolic genes in mammals. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Immobilization of flavin adenine dinucleotide (FAD) onto carbon cloth and its application as working electrode in an electroenzymatic bioreactor.

PubMed

Jayabalan, R; Sathishkumar, M; Jeong, E S; Mun, S P; Yun, S E

2012-11-01

A high porosity carbon cloth with immobilized FAD was employed as working electrode in electrochemical NADH-regeneration procedure. Carbon cloth was oxidized with hot acids to create surface carboxyl group and then coupled by adenine amino group of FAD with carbodiimide in the presence of N-hydroxysulfosuccinimide. The bioelectrocatalytic NADH-regeneration was coupled to the conversion of achiral substrate pyruvate into chiral product l-lactate by l-lactate dehydrogenase (l-LDH) within the same reactor. The conversion was completed at 96h in bioreactor with FAD-modified carbon cloth, resulting in about 6mM of l-lactate from 10mM of pyruvate. While with bare carbon cloth, the yield at 120h was around 5mM. Immobilized FAD on the surface of carbon cloth electrode facilitated it to carry electrons from electrode to electron transfer enzymes; thereby NADH-regeneration was accelerated to drive the enzymatic reaction efficiently. Copyright © 2012 Elsevier Ltd. All rights reserved.

Omega-3 Fatty Acid Deficiency Augments Risperidone-Induced Hepatic Steatosis in Rats: Positive Association with Stearoyl-CoA Desaturase

PubMed Central

McNamara, Robert K.; Magrisso, I. Jack; Hofacer, Rylon; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Benoit, Stephen C.

2012-01-01

Psychiatric patients frequently exhibit long-chain n-3 (LCn-3) fatty acid deficits and elevated triglyceride (TAG) production following chronic exposure to second generation antipsychotics (SGA). Emerging evidence suggests that SGAs and LCn-3 fatty acids have opposing effects on stearoyl-CoA desaturase-1 (SCD1), which plays a pivotal role in TAG biosynthesis. Here we evaluated whether low LCn-3 fatty acid status would augment elevations in rat liver and plasma TAG concentrations following chronic treatment with the SGA risperidone (RSP), and evaluated relationships with hepatic SCD1 expression and activity indices. In rats maintained on the n-3 fatty acid-fortified (control) diet, chronic RSP treatment significantly increased liver SCD1 mRNA and activity indices (18:1/18:0 and 16:1/16:0 ratios), and significantly increased liver, but not plasma, TAG concentrations. Rats maintained on the n-3 deficient diet exhibited significantly lower liver and erythrocyte LCn-3 fatty acid levels, and associated elevations in LCn-6/LCn-3 ratio. In n-3 deficient rats, RSP-induced elevations in liver SCD1 mRNA and activity indices (18:1/18:0 and 16:1/16:0 ratios) and liver and plasma TAG concentrations were significantly greater than those observed in RSP-treated controls. Plasma glucose levels were not altered by diet or RSP, and body weight was lower in RSP- and VEH-treated n-3 deficient rats. These preclinical data support the hypothesis that low n-3 fatty acid status exacerbates RSP-induced hepatic steatosis by augmenting SCD1 expression and activity. PMID:22750665

Bioinformatics analysis of the ς-carotene desaturase gene in cabbage (Brassica oleracea var. capitata)

NASA Astrophysics Data System (ADS)

Sun, Bo; Zheng, Aihong; Jiang, Min; Xue, Shengling; Zhang, Fen; Tang, Haoru

2018-04-01

ς-carotene desaturase (ZDS) is an important enzyme in carotenoid biosynthesis. Here, the Brassica oleracea var. capitata ZDS (BocZDS) gene sequences were obtained from Brassica database (BRAD), and preformed for bioinformatics analysis. The BocZDS gene mapped to Scaffold000363, and contains an open reading frame of 1,686 bp that encodes a 561-amino acid protein with a calculated molecular mass of 62.00 kD and an isoelectric point (pI) of 8.2. Subcellular localization predicted the BocZDS gene was in the chloroplast. The conserved domain of the BocZDS protein is PLN02487, indicating that it belongs the member of zeta-carotene desaturase. Homology analysis indicates that the ZDS protein is apparently conserved during plant evolution and is most closely related to B. oleracea var. oleracea, B. napus, and B. rapa. The findings of the present study provide a molecular basis for the elucidation of ZDS gene function in cabbage.

Stereochemistry of a bifunctional dihydroceramide delta 4-desaturase/hydroxylase from Candida albicans; a key enzyme of sphingolipid metabolism.

PubMed

Beckmann, Christoph; Rattke, Janine; Sperling, Petra; Heinz, Ernst; Boland, Wilhelm

2003-07-21

The stereochemical course of the dihydroceramide delta 4-(E)-desaturase from Candida albicans, cloned and expressed in the yeast Saccharomyces cerevisiae strain sur2 delta, was determined using stereospecifically labelled (2R,3S)-[2,3,4,4-2H4]-palmitic acid as a metabolic probe. Mass spectrometric analysis of the dinitrophenyl-derivatives of the labelled long-chain bases revealed elimination of a single deuterium atom from C(4) (corresponding to the C(4)-HR) along with a hydrogen atom from C(5) (corresponding to the C(5)-HS). This finding is consistent with an overall syn-elimination of the two vicinal hydrogen atoms. Besides the desaturation product sphingosine (93%) minor amounts of a 4-hydroxylated product (phytosphinganine, 7%) were identified that classify the Candida enzyme as a bifunctional desaturase/hydroxylase. Both processes, desaturation and hydroxylation proceed with loss of C(4)-HR from the chiral precursor. This finding is in agreement with a two-step process involving activation of the substrate by removal of the C(4)-HR to give a C-centred radical or radicaloid followed by either disproportionation into an olefin, water and a reduced diiron complex, or to recombination of the primary reactive intermediate with an active site-bound oxygen to yield a secondary alcohol. This result demonstrates the close mechanistic relationship between desaturation and hydroxylation as two different reaction pathways of a single enzyme and strengthens the mechanistic relationship of desaturases from fatty acid metabolism and sphingolipids.

Structural analysis of fungus-derived FAD glucose dehydrogenase

PubMed Central

Yoshida, Hiromi; Sakai, Genki; Mori, Kazushige; Kojima, Katsuhiro; Kamitori, Shigehiro; Sode, Koji

2015-01-01

We report the first three-dimensional structure of fungus-derived glucose dehydrogenase using flavin adenine dinucleotide (FAD) as the cofactor. This is currently the most advanced and popular enzyme used in glucose sensor strips manufactured for glycemic control by diabetic patients. We prepared recombinant nonglycosylated FAD-dependent glucose dehydrogenase (FADGDH) derived from Aspergillus flavus (AfGDH) and obtained the X-ray structures of the binary complex of enzyme and reduced FAD at a resolution of 1.78 Å and the ternary complex with reduced FAD and D-glucono-1,5-lactone (LGC) at a resolution of 1.57 Å. The overall structure is similar to that of fungal glucose oxidases (GOxs) reported till date. The ternary complex with reduced FAD and LGC revealed the residues recognizing the substrate. His505 and His548 were subjected for site-directed mutagenesis studies, and these two residues were revealed to form the catalytic pair, as those conserved in GOxs. The absence of residues that recognize the sixth hydroxyl group of the glucose of AfGDH, and the presence of significant cavity around the active site may account for this enzyme activity toward xylose. The structural information will contribute to the further engineering of FADGDH for use in more reliable and economical biosensing technology for diabetes management. PMID:26311535

Correlation of polyunsaturated fatty acids with the cold adaptation of Rhodotorula glutinis.

PubMed

He, Jing; Yang, Zhaojie; Hu, Binbin; Ji, Xiuling; Wei, Yunlin; Lin, Lianbing; Zhang, Qi

2015-11-01

This study aimed to investigate the correlation between the cold adaptation of Rhodotorula glutinis YM25079 and the membrane fluidity, content of polyunsaturated fatty acids and mRNA expression level of the Δ(12)-desaturase gene. The optimum temperature for YM25079 growth was analysed first, then the composition changes of membrane lipid in YM25079 were detected by GC-MS and membrane fluidity was evaluated by 1-anilinonaphthalene-8-sulphonate (ANS) fluorescence. Meanwhile, the encoding sequence of Δ(12)-fatty acid desaturase in YM25079 was cloned and further transformed into Saccharomyces cerevisiae INVScl for functional analysis. The mRNA expression levels of Δ(12)-fatty acid desaturase at 15°C and 25°C were analysed by real-time PCR. YM25079 could grow at 5-30°C, with the optimum temperature of 15°C. The membrane fluidity of YM25079 was not significantly reduced when the culture temperature decreased from 25°C to 15°C, but the content of polyunsaturated fatty acids (PUFAs), including linoleic acid and α-Linolenic acid increased significantly from 29.4% to 55.39%. Furthermore, a novel Δ(12)-fatty acid desaturase gene YM25079RGD12 from YM25079 was successfully identified and characterized, and the mRNA transcription level of the Δ(12)-desaturase gene was about five-fold higher in YM25079 cells grown at 15°C than that at 25°C. These results suggests that the cold adaptation of Rhodotorula glutinis YM25079 might result from higher expression of genes, especially the Δ(12)-fatty acid desaturase gene, during polyunsaturated fatty acids biosynthesis, which increased the content of PUFAs in the cell membrane and maintained the membrane fluidity at low temperature. Copyright © 2015 John Wiley & Sons, Ltd.

FAD oxidizes the ERO1-PDI electron transfer chain: The role of membrane integrity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papp, Eszter; Nardai, Gabor; Mandl, Jozsef

2005-12-16

The molecular steps of the electron transfer in the endoplasmic reticulum from the secreted proteins during their oxidation are relatively unknown. We present here that flavine adenine dinucleotide (FAD) is a powerful oxidizer of the oxidoreductase system, Ero1 and PDI, besides the proteins of rat liver microsomes and HepG2 hepatoma cells. Inhibition of FAD transport hindered the action of FAD. Microsomal membrane integrity was mandatory for all FAD-related oxidation steps downstream of Ero1. The PDI inhibitor bacitracin could inhibit FAD-mediated oxidation of microsomal proteins and PDI, but did not hinder the FAD-driven oxidation of Ero1. Our data demonstrated that Ero1more » can utilize FAD as an electron acceptor and that FAD-driven protein oxidation goes through the Ero1-PDI pathway and requires the integrity of the endoplasmic reticulum membrane. Our findings prompt further studies to elucidate the membrane-dependent steps of PDI oxidation and the role of FAD in redox folding.« less

Quick weight loss: sorting fad from fact.

PubMed

Roberts, D C

This article reviews popular diets for their ability to produce effective weight loss. Most of the "evidence" for fad diets is based on anecdotal findings, theories and testimonials of short term results. The most prominent elements of fad diets are those of ritual and sacrifice. These diets offer quick and painless weight loss while allowing consumption of favourite or tasty foods, but place severe restrictions on certain other foods or food categories. Fad diets often work in the short term because they are low-kilojoule diets in disguise; that is, energy intake as a result of the diet is lower than the person's requirements. Successful long term weight loss depends on the consumption over a long period of time of less energy than is expended. The ideal approach is to increase physical activity while modifying eating behaviour to achieve a nutritionally balanced intake.

Long-Chain Fatty Acyl Coenzyme A Ligase FadD2 Mediates Intrinsic Pyrazinamide Resistance in Mycobacterium tuberculosis

PubMed Central

Rosen, Brandon C.; Dillon, Nicholas A.; Peterson, Nicholas D.; Minato, Yusuke

2016-01-01

ABSTRACT Pyrazinamide (PZA) is a first-line tuberculosis (TB) drug that has been in clinical use for 60 years yet still has an unresolved mechanism of action. Based upon the observation that the minimum concentration of PZA required to inhibit the growth of Mycobacterium tuberculosis is approximately 1,000-fold higher than that of other first-line drugs, we hypothesized that M. tuberculosis expresses factors that mediate intrinsic resistance to PZA. To identify genes associated with intrinsic PZA resistance, a library of transposon-mutagenized Mycobacterium bovis BCG strains was screened for strains showing hypersusceptibility to the active form of PZA, pyrazinoic acid (POA). Disruption of the long-chain fatty acyl coenzyme A (CoA) ligase FadD2 enhanced POA susceptibility by 16-fold on agar medium, and the wild-type level of susceptibility was restored upon expression of fadD2 from an integrating mycobacterial vector. Consistent with the recent observation that POA perturbs mycobacterial CoA metabolism, the fadD2 mutant strain was more vulnerable to POA-mediated CoA depletion than the wild-type strain. Ectopic expression of the M. tuberculosis pyrazinamidase PncA, necessary for conversion of PZA to POA, in the fadD2 transposon insertion mutant conferred at least a 16-fold increase in PZA susceptibility under active growth conditions in liquid culture at neutral pH. Importantly, deletion of fadD2 in M. tuberculosis strain H37Rv also resulted in enhanced susceptibility to POA. These results indicate that FadD2 is associated with intrinsic PZA and POA resistance and provide a proof of concept for the target-based potentiation of PZA activity in M. tuberculosis. PMID:27855077

Enzyme-Mediated Conversion of Flavin Adenine Dinucleotide (FAD) to 8-Formyl FAD in Formate Oxidase Results in a Modified Cofactor with Enhanced Catalytic Properties.

PubMed

Robbins, John M; Souffrant, Michael G; Hamelberg, Donald; Gadda, Giovanni; Bommarius, Andreas S

2017-07-25

Flavins, including flavin adenine dinucleotide (FAD), are fundamental catalytic cofactors that are responsible for the redox functionality of a diverse set of proteins. Alternatively, modified flavin analogues are rarely found in nature as their incorporation typically results in inactivation of flavoproteins, thus leading to the disruption of important cellular pathways. Here, we report that the fungal flavoenzyme formate oxidase (FOX) catalyzes the slow conversion of noncovalently bound FAD to 8-formyl FAD and that this conversion results in a nearly 10-fold increase in formate oxidase activity. Although the presence of an enzyme-bound 8-formyl FMN has been reported previously as a result of site-directed mutagenesis studies of lactate oxidase, FOX is the first reported case of 8-formyl FAD in a wild-type enzyme. Therefore, the formation of the 8-formyl FAD cofactor in formate oxidase was investigated using steady-state kinetics, site-directed mutagenesis, ultraviolet-visible, circular dichroism, and fluorescence spectroscopy, liquid chromatography with mass spectrometry, and computational analysis. Surprisingly, the results from these studies indicate not only that 8-formyl FAD forms spontaneously and results in the active form of FOX but also that its autocatalytic formation is dependent on a nearby arginine residue, R87. Thus, this work describes a new enzyme cofactor and provides insight into the little-understood mechanism of enzyme-mediated 8α-flavin modifications.

Erv1p from Saccharomyces cerevisiae is a FAD-linked sulfhydryl oxidase.

PubMed

Lee, J; Hofhaus, G; Lisowsky, T

2000-07-14

The yeast ERV1 gene encodes a small polypeptide of 189 amino acids that is essential for mitochondrial function and for the viability of the cell. In this study we report the enzymatic activity of this protein as a flavin-linked sulfhydryl oxidase catalyzing the formation of disulfide bridges. Deletion of the amino-terminal part of Erv1p shows that the enzyme activity is located in the 15 kDa carboxy-terminal domain of the protein. This fragment of Erv1p still binds FAD and catalyzes the formation of disulfide bonds but is no longer able to form dimers like the complete protein. The carboxy-terminal fragment contains a conserved CXXC motif that is present in all homologous proteins from yeast to human. Thus Erv1p represents the first FAD-linked sulfhydryl oxidase from yeast and the first of these enzymes that is involved in mitochondrial biogenesis.

Hydrostatic pressure decreases membrane fluidity and lipid desaturase expression in chondrocyte progenitor cells.

PubMed

Montagne, Kevin; Uchiyama, Hiroki; Furukawa, Katsuko S; Ushida, Takashi

2014-01-22

Membrane biomechanical properties are critical in modulating nutrient and metabolite exchange as well as signal transduction. Biological membranes are predominantly composed of lipids, cholesterol and proteins, and their fluidity is tightly regulated by cholesterol and lipid desaturases. To determine whether such membrane fluidity regulation occurred in mammalian cells under pressure, we investigated the effects of pressure on membrane lipid order of mouse chondrogenic ATDC5 cells and desaturase gene expression. Hydrostatic pressure linearly increased membrane lipid packing and simultaneously repressed lipid desaturase gene expression. We also showed that cholesterol mimicked and cholesterol depletion reversed those effects, suggesting that desaturase gene expression was controlled by the membrane physical state itself. This study demonstrates a new effect of hydrostatic pressure on mammalian cells and may help to identify the molecular mechanisms involved in hydrostatic pressure sensing in chondrocytes. © 2013 Elsevier Ltd. All rights reserved.

Chromosome 14 and late-onset familial alzheimer disease (FAD)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schellenberg, G.D.; Anderson, L.; Nemens, E.

1993-09-01

Familial Alzheimer disease (FAD) is genetically heterogeneous. Two loci responsible for early-onset FAD have been identified: the amyloid precursor protein gene on chromosome 21 and the as-yet-unidentified locus on chromosome 14. The genetics of late-onset FAD is unresolved. Maximum-likelihood, affected-pedigree-member (APM), and sib-pair analysis were used, in 49 families with a mean age at onset [>=]60 years, to determine whether the chromosome 14 locus is responsible for late-onset FAD. The markers used were D14S53, D14S43, and D14S52. The LOD score method was used to test for linkage of late-onset FAD to the chromosome 14 markers, under three different models: age-dependentmore » penetrance, an affected-only analysis, and age-dependent penetrance with allowance for possible age-dependent sporadic cases. No evidence for linkage was obtained under any of these conditions for the late-onset kindreds, and strong evidence against linkage (LOD score [>=]2.0) to this region was obtained. Heterogeneity tests of the LOD score results for the combined group of families (early onset, Volga Germans, and late onset) favored the hypothesis of linkage to chromosome 14 with genetic heterogeneity. The positive results are primarily from early-onset families. APM analysis gave significant evidence for linkage of D14S43 and D14S52 to FAD in early-onset kindreds (P<.02). No evidence for linkage was found for the entire late-onset family group. Significant evidence for linkage to D14S52, however, was found for a subgroup of families of intermediate age at onset (mean age at onset [>=]60 years and <70 years). These results indicate that the chromosome 14 locus is not responsible for Alzheimer disease in most late-onset FAD kindreds but could play a role in a subset of these kindreds. 37 refs., 1 fig., 6 tabs.« less

Feeding steam-pelleted rapeseed affects expression of genes involved in hepatic lipid metabolism and fatty acid composition of chicken meat.

PubMed

Li, S; Vestergren, A Schiller; Wall, H; Trattner, S; Pickova, J; Ivarsson, E

2017-08-01

This study investigated the dietary effect of steam-pelleted rapeseed (RS) diets with different inclusion levels on the fatty acid composition of chicken meat and the expression of lipid metabolism-related genes in the liver. Experimental diets included 6 different wheat-soybean meal based diets either in nonpelleted or steam-pelleted form supplemented with 80, 160, and 240 g RS/kg feed and one nonpelleted wheat-soybean meal based diet without RS supplementation as the control. These diets were fed to newly hatched broiler chickens (Ross 308) for 34 days. Compared to the control diet, steam-pelleted diets containing 160 or 240 g/kg RS significantly increased the content of omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA) in the breast and drumstick, while their meat yields were not affected. Moreover, the mRNA levels of fatty acid desaturase 1 (FADS1) and acyl-coenzyme A oxidase 1 (ACOX1) in their livers increased. Therefore, steam-pelleted diets with 160 or 240 g/kg RS can be used to increase the n-3 LC-PUFA content in chicken meat without compromising meat yield. © 2017 Poultry Science Association Inc.

Evolution of the Insect Desaturase Gene Family with an Emphasis on Social Hymenoptera

PubMed Central

Helmkampf, Martin; Cash, Elizabeth; Gadau, Jürgen

2015-01-01

Desaturase genes are essential for biological processes, including lipid metabolism, cell signaling, and membrane fluidity regulation. Insect desaturases are particularly interesting for their role in chemical communication, and potential contribution to speciation, symbioses, and sociality. Here, we describe the acyl-CoA desaturase gene families of 15 insects, with a focus on social Hymenoptera. Phylogenetic reconstruction revealed that the insect desaturases represent an ancient gene family characterized by eight subfamilies that differ strongly in their degree of conservation and frequency of gene gain and loss. Analyses of genomic organization showed that five of these subfamilies are represented in a highly microsyntenic region conserved across holometabolous insect taxa, indicating an ancestral expansion during early insect evolution. In three subfamilies, ants exhibit particularly large expansions of genes. Despite these expansions, however, selection analyses showed that desaturase genes in all insect lineages are predominantly undergoing strong purifying selection. Finally, for three expanded subfamilies, we show that ants exhibit variation in gene expression between species, and more importantly, between sexes and castes within species. This suggests functional differentiation of these genes and a role in the regulation of reproductive division of labor in ants. The dynamic pattern of gene gain and loss of acyl-CoA desaturases in ants may reflect changes in response to ecological diversification and an increased demand for chemical signal variability. This may provide an example of how gene family expansions can contribute to lineage-specific adaptations through structural and regulatory changes acting in concert to produce new adaptive phenotypes. PMID:25425561

Bleaching herbicide norflurazon inhibits phytoene desaturase by competition with the cofactors.

PubMed

Breitenbach, J; Zhu, C; Sandmann, G

2001-11-01

Cofactor requirement was determined for the heterologous expressed phytoene desaturases from the cyanobacterium Synechococcus and the higher plant Gentiana lutea. The cyanobacterial enzyme is dependent on either NAD(P) or plastoquinone, whereas only quinones such as plastoquinone can function as a cofactor for the phytoene desaturase from G. lutea. Enzyme kinetic studies were carried out to determine a possible competition between the cofactors and the bleaching herbicide norflurazon. For the Synechococcus enzyme, competition between norflurazon and NADP, as well as plastoquinone, could be demonstrated. The K(m) values for these cofactors were 6.6 mM and 0.23 microM, respectively. Inhibition of the phytoene desaturase from G. lutea by norflurazon was also competitive with respect to plastoquinone. The K(m) values of both enzymes for plastoquinone were very close.

Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

PubMed Central

Wittkopp, Tyler M.; Warakanont, Jaruswan; Dubini, Alexandra; Catalanotti, Claudia; Kim, Rick G.; Nowack, Eva C. M.; Mackinder, Luke C. M.; Aksoy, Munevver; Page, Mark Dudley; D’Adamo, Sarah; Saroussi, Shai; Heinnickel, Mark; Johnson, Xenie; Richaud, Pierre; Alric, Jean; Boehm, Marko; Jonikas, Martin C.; Benning, Christoph; Merchant, Sabeeha S.; Posewitz, Matthew C.; Grossman, Arthur R.

2015-01-01

Photosynthetic microorganisms typically have multiple isoforms of the electron transfer protein ferredoxin, although we know little about their exact functions. Surprisingly, a Chlamydomonas reinhardtii mutant null for the ferredoxin-5 gene (FDX5) completely ceased growth in the dark, with both photosynthetic and respiratory functions severely compromised; growth in the light was unaffected. Thylakoid membranes in dark-maintained fdx5 mutant cells became severely disorganized concomitant with a marked decrease in the ratio of monogalactosyldiacylglycerol to digalactosyldiacylglycerol, major lipids in photosynthetic membranes, and the accumulation of triacylglycerol. Furthermore, FDX5 was shown to physically interact with the fatty acid desaturases CrΔ4FAD and CrFAD6, likely donating electrons for the desaturation of fatty acids that stabilize monogalactosyldiacylglycerol. Our results suggest that in photosynthetic organisms, specific redox reactions sustain dark metabolism, with little impact on daytime growth, likely reflecting the tailoring of electron carriers to unique intracellular metabolic circuits under these two very distinct redox conditions. PMID:26627249

Fad diets: facts for dental professionals.

PubMed

Mobley, Connie

2008-01-01

The author examined fad diet practices associated with oral health status and the role of the dental practitioner in addressing relevant issues. The author reviewed the literature regarding overweight and obesity in the United States to interpret issues that might arise in reviewing fad diet practices among dental patients. The author provides suggestions for assisting patients in choosing dietary and lifestyle behaviors that are based on current public health evidence in support of achieving and maintaining a healthy body weight. Dental professionals are well-positioned to guide patients toward dietary choices that support dental health and the attainment of a healthy weight associated with a decreased risk of developing chronic diseases.

Myosin-cross-reactive antigen (MCRA) protein from Bifidobacterium breve is a FAD-dependent fatty acid hydratase which has a function in stress protection.

PubMed

Rosberg-Cody, Eva; Liavonchanka, Alena; Göbel, Cornelia; Ross, R Paul; O'Sullivan, Orla; Fitzgerald, Gerald F; Feussner, Ivo; Stanton, Catherine

2011-02-17

The aim of this study was to determine the catalytic activity and physiological role of myosin-cross-reactive antigen (MCRA) from Bifidobacterium breve NCIMB 702258. MCRA from B. breve NCIMB 702258 was cloned, sequenced and expressed in heterologous hosts (Lactococcus and Corynebacterium) and the recombinant proteins assessed for enzymatic activity against fatty acid substrates. MCRA catalysed the conversion of palmitoleic, oleic and linoleic acids to the corresponding 10-hydroxy fatty acids, but shorter chain fatty acids were not used as substrates, while the presence of trans-double bonds and double bonds beyond the position C12 abolished hydratase activity. The hydroxy fatty acids produced were not metabolised further. We also found that heterologous Lactococcus and Corynebacterium expressing MCRA accumulated increasing amounts of 10-HOA and 10-HOE in the culture medium. Furthermore, the heterologous cultures exhibited less sensitivity to heat and solvent stresses compared to corresponding controls. MCRA protein in B. breve can be classified as a FAD-containing double bond hydratase, within the carbon-oxygen lyase family, which may be catalysing the first step in conjugated linoleic acid (CLA) production, and this protein has an additional function in bacterial stress protection.

Development of a pneumatic high-angle-of-attack Flush Airdata Sensing (HI-FADS) system

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Moes, Timothy R.; Leondes, Cornelius T.

1992-01-01

The HI-FADS system design is an evolution of the FADS systems (e.g., Larson et al., 1980, 1987), which emphasizes the entire airdata system development. This paper describes the HI-FADS measurement system, with particular consideration given to the basic measurement hardware and the development of the HI-FADS aerodynamic model and the basic nonlinear regression algorithm. Algorithm initialization techniques are developed, and potential algorithm divergence problems are discussed. Data derived from HI-FADS flight tests are used to demonstrate the system accuracies and to illustrate the developed concepts and methods.

Sex Pheromone Evolution Is Associated with Differential Regulation of the Same Desaturase Gene in Two Genera of Leafroller Moths

PubMed Central

Albre, Jérôme; Liénard, Marjorie A.; Sirey, Tamara M.; Schmidt, Silvia; Tooman, Leah K.; Carraher, Colm; Greenwood, David R.; Löfstedt, Christer; Newcomb, Richard D.

2012-01-01

Chemical signals are prevalent in sexual communication systems. Mate recognition has been extensively studied within the Lepidoptera, where the production and recognition of species-specific sex pheromone signals are typically the defining character. While the specific blend of compounds that makes up the sex pheromones of many species has been characterized, the molecular mechanisms underpinning the evolution of pheromone-based mate recognition systems remain largely unknown. We have focused on two sets of sibling species within the leafroller moth genera Ctenopseustis and Planotortrix that have rapidly evolved the use of distinct sex pheromone blends. The compounds within these blends differ almost exclusively in the relative position of double bonds that are introduced by desaturase enzymes. Of the six desaturase orthologs isolated from all four species, functional analyses in yeast and gene expression in pheromone glands implicate three in pheromone biosynthesis, two Δ9-desaturases, and a Δ10-desaturase, while the remaining three desaturases include a Δ6-desaturase, a terminal desaturase, and a non-functional desaturase. Comparative quantitative real-time PCR reveals that the Δ10-desaturase is differentially expressed in the pheromone glands of the two sets of sibling species, consistent with differences in the pheromone blend in both species pairs. In the pheromone glands of species that utilize (Z)-8-tetradecenyl acetate as sex pheromone component (Ctenopseustis obliquana and Planotortrix octo), the expression levels of the Δ10-desaturase are significantly higher than in the pheromone glands of their respective sibling species (C. herana and P. excessana). Our results demonstrate that interspecific sex pheromone differences are associated with differential regulation of the same desaturase gene in two genera of moths. We suggest that differential gene regulation among members of a multigene family may be an important mechanism of molecular innovation in

Design and Calibration of the X-33 Flush Airdata Sensing (FADS) System

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Cobleigh, Brent R.; Haering, Edward A.

1998-01-01

This paper presents the design of the X-33 Flush Airdata Sensing (FADS) system. The X-33 FADS uses a matrix of pressure orifices on the vehicle nose to estimate airdata parameters. The system is designed with dual-redundant measurement hardware, which produces two independent measurement paths. Airdata parameters that correspond to the measurement path with the minimum fit error are selected as the output values. This method enables a single sensor failure to occur with minimal degrading of the system performance. The paper shows the X-33 FADS architecture, derives the estimating algorithms, and demonstrates a mathematical analysis of the FADS system stability. Preliminary aerodynamic calibrations are also presented here. The calibration parameters, the position error coefficient (epsilon), and flow correction terms for the angle of attack (delta alpha), and angle of sideslip (delta beta) are derived from wind tunnel data. Statistical accuracy of' the calibration is evaluated by comparing the wind tunnel reference conditions to the airdata parameters estimated. This comparison is accomplished by applying the calibrated FADS algorithm to the sensed wind tunnel pressures. When the resulting accuracy estimates are compared to accuracy requirements for the X-33 airdata, the FADS system meets these requirements.

Cold perception and gene expression differ in Olea europaea seed coat and embryo during drupe cold acclimation.

PubMed

D'Angeli, S; Falasca, G; Matteucci, M; Altamura, M M

2013-01-01

FAD2 and FAD7 desaturases are involved in cold acclimation of olive (Olea europaea) mesocarp. There is no research information available on cold acclimation of seeds during mesocarp cold acclimation or on differences in the cold response of the seed coat and embryo. How FAD2 and FAD7 affect seed coat and embryo cold responses is unknown. Osmotin positively affects cold acclimation in olive tree vegetative organs, but its role in the seeds requires investigation. OeFAD2.1, OeFAD2.2, OeFAD7 and Oeosmotin were investigated before and after mesocarp acclimation by transcriptomic, lipidomic and immunolabelling analyses, and cytosolic calcium concentration ([Ca(2+)](cyt)) signalling, F-actin changes and seed development were investigated by epifluorescence/histological analyses. Transient [Ca(2+)](cyt) rises and F-actin disassembly were found in cold-shocked protoplasts from the seed coat, but not from the embryo. The thickness of the outer endosperm cuticle increased during drupe exposure to lowering of temperature, whereas the embryo protoderm always lacked cuticle. OeFAD2 transcription increased in both the embryo and seed coat in the cold-acclimated drupe, but linoleic acid (i.e. the product of FAD2 activity) increased solely in the seed coat. Osmotin was immunodetected in the seed coat and endosperm of the cold-acclimated drupe, and not in the embryo. The results show cold responsiveness in the seed coat and cold tolerance in the embryo. We propose a role for the seed coat in maintaining embryo cold tolerance by increasing endosperm cutinization through FAD2 and osmotin activities. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

An Icelandic Version of McMasters Family Assessment Device (FAD)

ERIC Educational Resources Information Center

Juliusdottir, Gudlaug M.; Olafsdottir, Hrefna

2015-01-01

Purpose: An analysis of the psychometric properties of an Icelandic version of McMasters Family Assessment Device (FAD) was conducted in this study. Method: Two groups, clinical and nonclinical, comprising of 529 parents answered the FAD. The study examined the internal reliability and discriminant validity of the instrument in addition to…

Efficient production of free fatty acids from ionic liquid-based acid- or enzyme-catalyzed bamboo hydrolysate.

PubMed

Mi, Le; Qin, Dandan; Cheng, Jie; Wang, Dan; Li, Sha; Wei, Xuetuan

2017-03-01

Two engineered Escherichia coli strains, DQ101 (MG1655 fadD - )/pDQTES and DQ101 (MG1655 fadD - )/pDQTESZ were constructed to investigate the free fatty acid production using ionic liquid-based acid- or enzyme-catalyzed bamboo hydrolysate as carbon source in this study. The plasmid, pDQTES, carrying an acyl-ACP thioesterase 'TesA of E. coli in pTrc99A was constructed firstly, and then (3R)-hydroxyacyl-ACP dehydratase was ligated after the TesA to give the plasmid pDQTESZ. These two strains exhibited efficient fatty acid production when glucose was used as the sole carbon source, with a final concentration of 2.45 and 3.32 g/L, respectively. The free fatty acid production of the two strains on xylose is not as efficient as that on glucose, which was 2.32 and 2.96 g/L, respectively. For mixed sugars, DQ101 (MG1655 fadD - )-based strains utilized glucose and pentose sequentially under the carbon catabolite repression (CCR) regulation. The highest total FFAs concentration from the mixed sugar culture reached 2.81 g/L by DQ101 (MG1655 fadD - )/pDQTESZ. Furthermore, when ionic liquid-based enzyme-catalyzed bamboo hydrolysate was used as the carbon source, the strain DQ101 (MG1655 fadD - )/pDQTESZ could produce 1.23 g/L FFAs with a yield of 0.13 g/g, and while it just produced 0.65 g/L free fatty acid with the ionic liquid-based acid-catalyzed bamboo hydrolysate as the feedstock. The results suggested that enzymatic catalyzed bamboo hydrolysate with ionic liquid pretreatment could serve as an efficient feedstock for free fatty acid production.

The contribution of nearshore fish aggregating devices (FADs) to food security and livelihoods in Solomon Islands.

PubMed

Albert, Joelle A; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L

2014-01-01

Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12,000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks.

The Contribution of Nearshore Fish Aggregating Devices (FADs) to Food Security and Livelihoods in Solomon Islands

PubMed Central

Albert, Joelle A.; Beare, Doug; Schwarz, Anne-Maree; Albert, Simon; Warren, Regon; Teri, James; Siota, Faye; Andrew, Neil L.

2014-01-01

Fish aggregating devices, or FADs, are used widely in developing countries to concentrate pelagic fish, making them easier to catch. Nearshore FADs anchored close to the coast allow access for rural communities, but despite their popularity among policy makers, there is a dearth of empirical analysis of their contributions to the supply of fish and to fisheries management. In this paper we demonstrate that nearshore FADs increased the supply of fish to four communities in Solomon Islands. Estimated total annual fish catch ranged from 4300 to 12 000 kg across the study villages, with nearshore FADs contributing up to 45% of the catch. While it is clear that FADs increased the supply of fish, FAD catch rates were not consistently higher than other fishing grounds. Villages with limited access to diverse or productive fishing grounds seemingly utilized FADs to better effect. Villagers believed FADs increased household income and nutrition, as well as providing a source of fish for community events. FADs were also perceived to increase intra-household conflict and reduce fishers' participation in community activities. FADs need to be placed within a broader rural development context and treated as another component in the diversified livelihoods of rural people; as with other livelihood options they bring trade-offs and risks. PMID:25513808

The EFQM Excellence Model[R]: Higher Education's Latest Management Fad?

ERIC Educational Resources Information Center

Temple, Paul

2005-01-01

Robert Birnbaum argues that higher education tends to adopt management fads -- newly conceived techniques enjoying brief popularity but which fail to live up to their promoters claims at the point when the corporate sector and government are discarding them. Although fads may have failed in these sectors because of various reasons, their failure…

Effect of varying dietary levels of LC-PUFA and vegetable oil sources on performance and fatty acids of Senegalese sole post larvae: puzzling results suggest complete biosynthesis pathway from C18 PUFA to DHA.

PubMed

Navarro-Guillén, Carmen; Engrola, Sofia; Castanheira, Filipa; Bandarra, Narcisa; Hachero-Cruzado, Ismael; Tocher, Douglas R; Conceição, Luís E C; Morais, Sofia

2014-01-01

Lipid nutrition of marine fish larvae has focused on supplying essential fatty acids (EFA) at high levels to meet requirements for survival, growth and development. However, some deleterious effects have been reported suggesting that excessive supply of EFA might result in insufficient supply of energy substrates, particularly in species with lower EFA requirements such as Senegalese sole (Solea senegalensis). This study addressed how the balance between EFA and non-EFA (better energy sources) affects larval performance, body composition and metabolism and retention of DHA, by formulating enrichment emulsions containing two different vegetable oil sources (olive oil or soybean oil) and three DHA levels. DHA positively affected growth and survival, independent of oil source, confirming that for sole post-larvae it is advantageous to base enrichments on vegetable oils supplying higher levels of energy, and supplement these with a DHA-rich oil. In addition, body DHA levels were generally comparable considering the large differences in their dietary supply, suggesting that the previously reported ∆4 fatty acyl desaturase (fad) operates in vivo and that DHA was synthesized at physiologically significant rates through a mechanism involving transcriptional up-regulation of ∆4fad, which was significantly up-regulated in the low DHA treatments. Furthermore, data suggested that DHA biosynthesis may be regulated by an interaction between dietary n-3 and n-6 PUFA, as well as by levels of LC-PUFA, and this may, under certain nutritional conditions, lead to DHA production from C18 precursors. The molecular basis of putative fatty acyl ∆5 and ∆6 desaturation activities remains to be fully determined as thorough searches have found only a single (∆4) Fads2-type transcript. Therefore, further studies are required but this might represent a unique activity described within vertebrate fads. © 2013.

Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants

DOEpatents

Ohlrogge, John B.; Cahoon, Edgar B.; Shanklin, John; Somerville, Christopher R.

1995-01-01

The present invention relates to a process for producing lipids containing the fatty acid petroselinic acid in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a .omega.12 desaturase from another species which does normally accumulate petroselinic acid.

Longitudinal associations of serum fatty acid composition with type 2 diabetes risk and markers of insulin secretion and sensitivity in the Finnish Diabetes Prevention Study.

PubMed

Takkunen, Markus J; Schwab, Ursula S; de Mello, Vanessa D F; Eriksson, Johan G; Lindström, Jaana; Tuomilehto, Jaakko; Uusitupa, Matti I J

2016-04-01

To examine the longitudinal associations of serum fatty acid composition with type 2 diabetes, insulin secretion and insulin sensitivity over several years. We conducted a prospective cohort study derived from the randomized Finnish Diabetes Prevention Study. Total serum fatty acid composition was measured using gas chromatography in 407 overweight, middle-aged people with impaired glucose tolerance at baseline (1993-1998) and annually during the intervention period (1994-2000). Longitudinal associations of 20 fatty acids and three desaturase activities (Δ5 (20:4n-6/20:3n-6, D5D), Δ6 (18:3n-6/18:2n-6, D6D), stearoyl-CoA desaturase-1 (16:1n-7/16:0, SCD-1)) with type 2 diabetes incidence, and estimates of insulin sensitivity (Matsuda), secretion (ratio of insulin and glucose concentrations) and β-cell function (disposition index) by an oral glucose tolerance test were analyzed using Cox regression and linear mixed models. We validated estimated D5D and D6D using a known FADS1 gene variant, rs174550. The baseline proportions of 20:5n-3, 22:5n-3 and 22:6n-3, and D5D were associated with lower incidence of type 2 diabetes during a median follow-up of 11 years (HR per 1SD: 0.72, 0.74, 0.73, 0.78, respectively, P ≤ 0.01). These long-chain omega-3 fatty acids and D5D were associated with higher insulin sensitivity in subsequent years but not with disposition index. Saturated, monounsaturated and trans fatty acids and 18:3n-3, 18:2n-6, SCD-1 and D6D were inconsistently associated with type 2 diabetes or related traits. Serum long-chain omega-3 fatty acids and D5D predicted lower type 2 diabetes incidence in people at a high risk of diabetes attending to an intervention study; a putative mechanism behind these associations was higher insulin sensitivity.