The surprising diversity of Δ6-desaturase substrates

2004 ◽  
Vol 32 (1) ◽  
pp. 86-87 ◽  
Author(s):  
H. Guillou ◽  
S. D'Andrea ◽  
V. Rioux ◽  
S. Jan ◽  
P. Legrand

A single gene encoding a δ6-desaturase (FADS2) has been isolated and characterized in mammalian species. This δ6-desaturase plays a major role in the biosynthesis of PUFAs (polyunsaturated fatty acids). It catalyses the rate-limiting desaturation of linoleic acid (C18:2n−6) and α-linolenic acid (C18:3n−3) required for the biosynthesis of long-chain PUFAs. Moreover, recent studies have provided strong evidence that this δ6-desaturase also acts on 24-carbon PUFAs of both the n−6 and n−3 series. Another substrate of this δ6-desaturase has been identified through complementary works from different investigators. This δ6-desaturase acts on a saturated fatty acid, palmitic acid (C16:0), leading to the newly characterized biosynthesis of hexadecenoic acid (C16:1n−10) or sapienate.

2002 ◽  
Vol 364 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sabine D'ANDREA ◽  
Hervé GUILLOU ◽  
Sophie JAN ◽  
Daniel CATHELINE ◽  
Jean-Noël THIBAULT ◽  
...  

The recently cloned Δ6-desaturase is known to catalyse the first step in very-long-chain polyunsaturated fatty acid biosynthesis, i.e. the desaturation of linoleic and α-linolenic acids. The hypothesis that this enzyme could also catalyse the terminal desaturation step, i.e. the desaturation of 24-carbon highly unsaturated fatty acids, has never been elucidated. To test this hypothesis, the activity of rat Δ6-desaturase expressed in COS-7 cells was investigated. Recombinant Δ6-desaturase expression was analysed by Western blot, revealing a single band at 45kDa. The putative involvement of this enzyme in the Δ6-desaturation of C24:5n-3 to C24:6n-3 was measured by incubating transfected cells with C22:5n-3. Whereas both transfected and non-transfected COS-7 cells were able to synthesize C24:5n-3 by elongation of C22:5n-3, only cells expressing Δ6-desaturase were also able to produce C24:6n-3. In addition, Δ6-desaturation of [1-14C]C24:5n-3 was assayed invitro in homogenates from COS-7 cells expressing Δ6-desaturase or not, showing that Δ6-desaturase catalyses the conversion of C24:5n-3 to C24:6n-3. Evidence is therefore presented that the same rat Δ6-desaturase catalyses not only the conversion of C18:3n-3 to C18:4n-3, but also the conversion of C24:5n-3 to C24:6n-3. A similar mechanism in the n-6 series is strongly suggested.


2020 ◽  
pp. 1-26
Author(s):  
Yan Wang ◽  
Yiwei Tang ◽  
Ye Ji ◽  
Wenhui Xu ◽  
Naeem Ullah ◽  
...  

Abstract In this study, we analysed the effects of single nucleotide polymorphism (SNP) rs174547 (T/C) in the fatty acid desaturase 1 (FADS1) gene on long-chain polyunsaturated fatty acid levels. Four databases were searched to retrieve related literature with keywords such as fatty acid, SNP, FADS1, and rs174547. A meta-analysis of the data was performed using Stata12.0 software, including summary statistics, test for heterogeneity, evaluation of publication bias, subgroup analysis, and sensitivity analysis. The associations between rs174547 in FADS1 and seven types of fatty acids, and delta-5 (D5D) and delta-6 fatty acid desaturase (D6D) activity were assessed based on the pooled results from 11 manuscripts. A total of 3713 individuals (1529 TT and 2184 TC+CC) were included. The results demonstrated that minor C allele carriers of rs174547 had higher linoleic acid (LA; P < 0.001) and α-linolenic acid (P = 0.020) levels, lower gamma linoleic acid (GLA; P = 0.001) and arachidonic acid (P = 0.024) levels, and lower D5D (P = 0.005) and D6D (P = 0.004) activities than the TT genotype group. Stratification analysis showed that minor C allele carriers of rs174547 had higher LA and lower GLA levels and lower D6D activities in plasma (LA, P < 0.001; GLA, P < 0.001; D6D activity, P < 0.001) samples and in Asian populations (LA, P < 0.001; GLA, P = 0.001; D6D activity, P = 0.001) than the TT genotype group. In conclusion, minor C allele carriers of the SNP rs174547 were associated with decreased activity of D5D and D6D.


2008 ◽  
Vol 74 (14) ◽  
pp. 4292-4299 ◽  
Author(s):  
Sofia Windstam ◽  
Eric B. Nelson

ABSTRACT The aim of this study was to determine the temporal release of fatty acids and sugars from corn and cucumber seeds during the early stages of seed germination in order to establish whether sugars found in exudate can prevent exudate fatty acid degradation by Enterobacter cloacae. Both saturated (long-chain saturated fatty acids [LCSFA]) and unsaturated (long-chain unsaturated fatty acids [LCUFA]) fatty acids were detected in corn and cucumber seed exudates within 15 min after seed sowing. LCSFA and LCUFA were released at a rate of 26.1 and 6.44 ng/min/seed by corn and cucumber seeds, respectively. The unsaturated portion of the total fatty acid pool from both plant species contained primarily oleic and linoleic acids, and these fatty acids were released at a combined rate of 6.6 and 0.67 ng/min/seed from corn and cucumber, respectively. In the absence of seed exudate sugars, E. cloacae degraded linoleic acid at rates of 29 to 39 ng/min, exceeding the rate of total fatty acid release from seeds. Sugars constituted a significant percentage of corn seed exudate, accounting for 41% of the total dry seed weight. Only 5% of cucumber seed exudate was comprised of sugars. Glucose, fructose, and sucrose were the most abundant sugars present in seed exudate from both plant species. Corn seeds released a total of 137 μg/seed of these three sugars within 30 min of sowing, whereas cucumber seeds released 0.83 μg/seed within the same time frame. Levels of glucose, fructose, and sucrose found in corn seed exudate (90 to 342 μg) reduced the rate of linoleic acid degradation by E. cloacae to 7.5 to 8.8 ng/min in the presence of either sugar, leaving sufficient concentrations of linoleic acid to activate Pythium ultimum sporangia Our results demonstrate that elevated levels of sugars in the corn spermosphere can prevent the degradation of LCUFA by E. cloacae, leading to its failure to suppress P. ultimum sporangial activation, germination, and subsequent disease development.


2007 ◽  
Vol 2007 ◽  
pp. 151-151 ◽  
Author(s):  
E. J. Kim ◽  
J. D. Wood ◽  
I. Richardson ◽  
S. A. Huws ◽  
N. D. Scollan

Previous studies have shown that including fish oil (FO) in the diet of beef cattle resulted in increased long chain C20n-3 PUFA (C20:5n-3 and C22:6n-3) in muscle resulting in a lower n-6:n-3 ratio (Scollan et al., 2005). Fish oil is considered to be a good inhibitor of biohydrogenation in the rumen, resulting in increased production of C18:1 trans-11 (Vaccenic acid), the precursor for conjugated linoleic acid (CLA cis-9, trans-11) in muscle. This study investigated the effects of incremental levels of FO in the diet on fatty acid metabolism in the rumen.


1961 ◽  
Vol 39 (12) ◽  
pp. 1855-1863 ◽  
Author(s):  
Joyce L. Beare

Fatty acids of liver, carcass, and milk of rats fed corn oil, rapeseed oil, partially hydrogenated herring oil, or margarine were examined by gas–liquid chromatography. Appreciable quantities of linoleic acid were maintained in the tissues and milk, even when the hydrogenated herring oil with a low level of linoleic acid was fed. The proportion of C20and C22acids deposited or secreted was related to that of the diet, and was highest with rapeseed oil. In the livers of rats fed each diet, long-chain, polyunsaturated acids were observed. The fatty acids of milk more closely reflected the dietary pattern than did those of the tissues.


2019 ◽  
Author(s):  
Aleksandra Mitina ◽  
Pavel Mazin ◽  
Anna Vanyushkina ◽  
Nikolay Anikanov ◽  
Waltraud Mair ◽  
...  

Abstract Background Lipids contained in breast milk are an essential source of energy and structural materials for a growing infant. Furthermore, lipids’ long-chain unsaturated fatty acid residues can directly participate in infant tissue formation. Here, we used untargeted mass spectrometric measurements to assess breast milk lipid composition in seven mammalian species: humans, two macaque species, cows, goats, yaks, and pigs.Results Analysis of the main milk lipid class, triacylglycerides, revealed species-specific differences in the composition of fatty acid residues for each of seven species. While human milk showed more medium and long-chain unsaturated fatty acids, pig milk composition was the most distinct, featuring the highest proportion of long-chain polyunsaturated fatty acids. Conclusions We show that breast milk lipidome composition is dynamic across mammalian species, changed extensively in pigs, and contains features particular to humans.


1968 ◽  
Vol 46 (9) ◽  
pp. 1523-1528 ◽  
Author(s):  
A. P. Tulloch ◽  
J. F. T. Spencer

Esters and hydrocarbons, containing 14 and 15 carbon atoms, are converted to the hydroxy fatty acid portions of glycosides by Torulopsis apicola in yields of 10–20%. When C-15 compounds are fermented, almost half of the hydroxy acids which are produced are 16-hydroxy C-17 acids. The carbon chain of the substrate is first lengthened by two carbon atoms and then hydroxylated. Direct hydroxylation also occurs, to a lesser extent, giving both 14-hydroxy- and 15-hydroxypentadecanoic acids. Similar results are obtained when C-14 compounds are used. Lengthening of the chain followed by hydroxylation gives rise to hydroxy C-16 acids and direct hydroxylation produces 13-hydroxy- and 14-hydroxytetradecanoic acids. Primary and secondary C-14 and C-15 alcohols were also isolated from the products of hydrocarbon fermentation (2.5–5 % yield). Methyl palmitoleate is converted to hydroxy fatty acids in yields of 40–70%, the major component of which is 16-hydroxy-cis-9-hexadecenoic acid.


2020 ◽  
Author(s):  
Aleksandra Mitina ◽  
Pavel Mazin ◽  
Anna Vanyushkina ◽  
Nikolay Anikanov ◽  
Waltraud Mair ◽  
...  

Abstract Background Lipids contained in milk are an essential source of energy and structural materials for a growing infant. Furthermore, lipids’ long-chain unsaturated fatty acid residues can directly participate in infant tissue formation. Here, we used untargeted mass spectrometric measurements to assess milk lipid composition in seven mammalian species: humans, two macaque species, cows, goats, yaks, and pigs.Results Analysis of the main milk lipid class, triacylglycerides, revealed species-specific quantitative differences in the composition of fatty acid residues for each of seven species. Overall, differences in milk lipid composition reflect evolutionary distances among species, with each species group demonstrating specific lipidome features. Among them, human milk contained more medium and long-chain unsaturated fatty acids compared to other species, while pig milk was the most distinct, featuring the highest proportion of long-chain polyunsaturated fatty acids. Conclusions We show that milk lipidome composition is dynamic across mammalian species, changed extensively in pigs, and contains features particular to humans.


2005 ◽  
Vol 94 (2) ◽  
pp. 221-230 ◽  
Author(s):  
A. García-de-Lorenzo ◽  
R. Denia ◽  
P. Atlan ◽  
S. Martinez-Ratero ◽  
A. Le Brun ◽  
...  

It has been claimed that lipid emulsions with a restricted linoleic acid content can improve the safety of total parenteral nutrition (TPN). The tolerability of TPN and its effects on the metabolism of fatty acids were assessed in this prospective, double-blind, randomised study comparing an olive/soyabean oil long-chain triacylglycerol (LCT) with a medium-chain triacylglycerol (MCT)/LCT; 50:50 (w) based lipid emulsion in two groups (O and M, respectively; eleven per group) of severely burned patients. After resuscitation (48–72 h), patients received TPN providing 147 kJ/kg per d (35 kcal/kg per d) with fat (1·3 g/kg per d) for 6 d Plasma fatty acids, laboratory parameters including liver function tests, and plasma cytokines were assessed before and after TPN. Adverse events encountered during TPN and the clinical outcomes of patients within the subsequent 6 months were recorded. With both lipid emulsions, the conversion of linoleic acid in its higher derivatives (di-homo-γ-linolenic acid) improved and essential fatty acid deficiency did not appear. Abnormalities of liver function tests occurred more frequently in the M (nine) than in the O (three) group (P=0·04, Suissa–Shuster test). Seven patients (four from group O and three from group M) died as a consequence of severe sepsis 3–37 d after completion of the 6 d TPN period. When compared with the surviving patients, those who died were older (P=0·01) and hyperglycaemic at baseline (P<0·001), and their plasma IL-6 levels continued to increase (P<0·04). Although fatty acid metabolism and TPN tolerability were similar with both lipid emulsions, the preservation of liver function noted with the use of the olive oil-based lipid emulsions deserves confirmation.


1995 ◽  
Vol 269 (2) ◽  
pp. E247-E252 ◽  
Author(s):  
H. O. Ajie ◽  
M. J. Connor ◽  
W. N. Lee ◽  
S. Bassilian ◽  
E. A. Bergner ◽  
...  

To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.


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