scholarly journals Active synthesis of C24:5, n-3 fatty acid in retina

1996 ◽  
Vol 316 (3) ◽  
pp. 859-864 ◽  
Author(s):  
N. P. ROTSTEIN ◽  
G. L. PENNACCHIOTTI ◽  
H. SPRECHER ◽  
M. I. AVELDAÑO

The formation of 14C-labelled long-chain and very-long-chain (n-3) pentaenoic and hexaenoic fatty acids was studied in bovine retina by following the metabolism of [14C]docosapentaenoate [C22:5, n-3 fatty acid (22:5 n-3)], [14C]docosahexaenoate (22:6 n-3), and [14C]acetate. With similar amounts of 22:5 n-3 and 22:6 n-3 as substrates, the former was actively transformed into 24:5 n-3, whereas the latter was virtually unmodified. Labelled 24:5, 26:5, 24:6 and 22:6 were formed from [1-14C]22:5 n-3, showing that pentaenoic fatty acids including 24:5 n-3 can be elongated and desaturated within the retina. When retinal microsomes were incubated with [1-14C]22:5 n-3, 24:5 n-3 was the only fatty acid formed. In retinas incubated with [14C]acetate, 24:5 n-3 was the most highly labelled fatty acid among the polyenes synthesized, 24:6 n-3 being a minor product. Such selectivity in the elongation of two fatty acids identical in length, 22:5 n-3 and 22:6 n-3, despite the fact that 22:5 is a minor and 22:6 a major fatty acid constituent of retina, suggests that the active formation of 24:5 n-3 plays a key role in n-3 polyunsaturated fatty acid (PUFA) metabolism. This compound might give rise to even longer pentaenes via elongation, and to the major PUFAs of retina, 22:6 n-3, by 6-desaturation and chain shortening. Of all retinal lipids, a minor component, triacylglycerol (TG), incorporated the largest amounts of [14C]22:5 and 22:6. TG also concentrated most of the [14C]24:5 formed in retina, whether from [14C]22:5 n-3 or from [14C]acetate, suggesting an important role for this lipid in supporting PUFA metabolism and the synthesis of 22:6 n-3.

1962 ◽  
Vol 40 (7) ◽  
pp. 847-855 ◽  
Author(s):  
D. C. Leegwater ◽  
C. G. Youngs ◽  
J. F. T. Spencer ◽  
B. M. Craig

The production of neutral lipids and phospholipids by submerged cultures of the mushroom Tricholoma nudum, as well as the fatty acid composition of these two fractions, was studied as a function of time. The bulk of the neutral lipids was produced after 2 days when the organism appeared to be in a non-proliferative phase. The major fatty acids of the neutral lipids were palmitic, oleic, and linoleic acid (23–35% each); stearic acid was a minor component (8–13%); myristic, palmitoleic, and linolenic acid were present in small amounts (0.5–4.8%). The major fatty acid of the phospholipids was linoleic acid (55–70%); palmitic (15–19%), stearic (1.8–4.6%), and oleic (7–19%) acid were minor components; myristic, palmitoleic, and linolenic (0–2.3%) were present in small amounts. Linolenic acid was a major fatty acid (26–30%) only in the early stages of growth.A preliminary investigation was carried out with a 4-day-old culture to establish the identity of the various components of the neutral lipids and phospholipids. The neutral lipids were mainly triglycerides (92%). Small amounts of ergosterol esters (1%), free fatty acids (< 1%), ergosterol (1.7%), and unidentified non-saponifiable compounds were also present. The phospholipids contained phosphatidyl choline (59%) as the major component; phosphatidyl ethanolamine (26%), phosphatidyl serine and phosphatidic acid (7.8%), and an inositol containing phospholipid were minor components.Some of the techniques applied were specially developed for the present type of studies and are described in detail.


1962 ◽  
Vol 40 (1) ◽  
pp. 847-855 ◽  
Author(s):  
D. C. Leegwater ◽  
C. G. Youngs ◽  
J. F. T. Spencer ◽  
B. M. Craig

The production of neutral lipids and phospholipids by submerged cultures of the mushroom Tricholoma nudum, as well as the fatty acid composition of these two fractions, was studied as a function of time. The bulk of the neutral lipids was produced after 2 days when the organism appeared to be in a non-proliferative phase. The major fatty acids of the neutral lipids were palmitic, oleic, and linoleic acid (23–35% each); stearic acid was a minor component (8–13%); myristic, palmitoleic, and linolenic acid were present in small amounts (0.5–4.8%). The major fatty acid of the phospholipids was linoleic acid (55–70%); palmitic (15–19%), stearic (1.8–4.6%), and oleic (7–19%) acid were minor components; myristic, palmitoleic, and linolenic (0–2.3%) were present in small amounts. Linolenic acid was a major fatty acid (26–30%) only in the early stages of growth.A preliminary investigation was carried out with a 4-day-old culture to establish the identity of the various components of the neutral lipids and phospholipids. The neutral lipids were mainly triglycerides (92%). Small amounts of ergosterol esters (1%), free fatty acids (< 1%), ergosterol (1.7%), and unidentified non-saponifiable compounds were also present. The phospholipids contained phosphatidyl choline (59%) as the major component; phosphatidyl ethanolamine (26%), phosphatidyl serine and phosphatidic acid (7.8%), and an inositol containing phospholipid were minor components.Some of the techniques applied were specially developed for the present type of studies and are described in detail.


1980 ◽  
Vol 191 (2) ◽  
pp. 555-560 ◽  
Author(s):  
G P Hazlewood ◽  
N G Clarke ◽  
R M C Dawson

The complex lipids of the naturally-occurring general-fatty-acid-auxotroph Butyrivibrio S2 [Hazlewood & Dawson (1979) J. Gen. Microbiol. 112, 15-27] grown with palmitic acid as sole fatty-acid supplement have been investigated and some have been isolated in a state of purity and analysed. The majority are phospholipids (84%) and many contain galactose. They typically possess few esterified long-chain fatty-acid residues (C16:0), but are rich in esterified butyric acid and C16-alkenyl groups. Most of the phosphorus-containing lipids, including the two major lipids of the organism, contain esterified diabolic acid, a long-chain vicinal dimethyl-substituted dicarboxylic acid [Klein, Hazlewood, Kemp & Dawson (1979) Biochem. J. 183, 691-700] in definite stoichiometric relationship to phosphorus. No phosphatidylglycerol was present, but its monobutyroyl ester was detected as a minor component. Galactofuranosyldiacylglycerol (plasmalogen) and its monobutyroyl ester, cetyl alcohol and diacylglycerol were also identified.


1990 ◽  
Vol 68 (1) ◽  
pp. 154-160 ◽  
Author(s):  
E. Yasugi ◽  
T. Kasama ◽  
M. Shibahara ◽  
Y. Seyama

Sphingomyelin from the guinea pig Harderian gland was isolated and characterized. The purified sphingomyelin gave a broad spot on thin-layer chromatography. The fatty acid composition of the whole sphingomyelin was 71% nonhydroxy acids and 29% 2-hydroxy acids. Methyl-branched fatty acids were only 2% of the total acids. The long-chain bases were composed of straight-chain sphingenines (50%) and sphinganines (6%). Methyl-branched long-chain bases were 44% of the bases. The sphingomyelin was further separated into four fractions (I, II, III, IV) by high-performance liquid chromatography. The ratio of fractions I, II, III, and IV was approximately 2:5:2:1, respectively. The fatty acids of fractions I and II consisted of nonhydroxy acids and those of fractions III and IV were 2-hydroxy acids. The long-chain bases of fractions I and III were sphinganines including 10-, 9-, and 8-methylsphinganines and anteiso-sphinganines. These methyl-branched bases occupied about 70% of the total sphinganines. The long-chain bases of fractions II and IV consisted of sphingenines. The methyl-branched unsaturated bases were only 30% of the total sphingenines, all in the anteiso-form. Thus, the sphingomyelin obtained from guinea pig Harderian gland had complex compositions of fatty acids and long-chain bases, and half the number of long-chain bases had methyl branches. The methyl-branched fatty acids were only a minor component. These characteristics are similar to those of cerebrosides isolated from the same source.Key words: long chain base, fatty acid, sphingomyelin, guinea pig, Harderian gland.


1976 ◽  
Vol 3 (6) ◽  
pp. 635-636
Author(s):  
R J Stretton ◽  
R K Dart

A number of strains purporting to belong to the species Sporothrix schenckii were examined for their fatty acid content. The majority of the strains were isolated from cases of sporotrichosis. Two strains were reputedly saprophytic. In all cases except the two saprophytic ones the major fatty acid was a C18 diene. Considerable amounts of palmitic acid and C18 monoene were found in all strains.


Animals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 389 ◽  
Author(s):  
Shi ◽  
Wang ◽  
Luo ◽  
Liu ◽  
Loor ◽  
...  

In humans, fatty acid elongase 7 (ELOVL7) plays a role in synthesis of long-chain saturated fatty acids. Whether ELOVL7 protein plays a role in ruminants is unclear. The transcript abundance of ELOVL7 in goat mammary tissue was assessed at three stages of lactation. Results showed that ELOVL7 had the highest expression in the dry period compared with peak and late lactation period. Results revealed that ELOVL7 overexpression was correlated with lower expression in diacylglycerol O-acyltransferase 2 (DGAT2) and stearoyl-CoA desaturase 1 (SCD1), and had no significant effect on triacylglycerol concentration. Overexpression of ELOVL7 significantly decreased the concentration of palmitoleic (C16:1n7) and oleic (C18:1n9) acid, and increased the concentration of vaccenic (C18:1n7) and linoleic (C18:2) acid. Overexpression of ELOVL7 significantly upregulated the elongation index of C16:1 in goat epithelial mammary cells (GMEC), but had a minor effect on that of palmitate (C16:0). Knockdown of ELOVL7 decreased mRNA expression of fatty acid binding protein 3 (FABP3) and fatty acid desaturase 2 (FADS2) and had a minor effect on triacylglycerol concentration; however, it increased concentration of C18:1n9 in GMEC. The elongation indices of C16:0 and C16:1 did not differ due to knockdown of ELOVL7. The minor change for the C16:0 and stearate (C18:0) was observed after activation of ELOVL7, suggesting the two fatty acids are not the preferential substrates of ELOVL7 in cultured GMEC. However, changes in C18:1n9 and C18:2 after overexpression or knockdown of ELOVL7 indicated a biological functional role of ELOVL7. Collectively, our data highlighted a role of ELOVL7 in long-chain unsaturated fatty acid elongation in goat mammary epithelial cells.


1970 ◽  
Vol 37 (2) ◽  
pp. 297-301 ◽  
Author(s):  
R. C. Noble ◽  
W. Steele ◽  
J. H. Moore

SummaryThe composition of ewe's milk during the first 4 days of lactation and on the 100th day of lactation was investigated. The total fat content was highest (17· 9%) on the day of parturition but decreased rapidly to reach a level on the 2nd day after parturition that was similar to that observed on the 100th day of lactation (9·9 %).The concentration of octadecenoic acid, which was the major fatty acid of ewe's milk, was very much higher in early lactation than in late lactation. As the concentration of octadecenoic acid decreased the concentration of the shorter chain fatty acids (6:0−14:0) increased. The major octadecenoic acid was the cis-9 isomer. However, the proportion of the trans-11 isomer increased from 5·5 % of the total octadecenoic acid concentration in early lactation to 11·9 % in late lactation. Although linoleic acid remained a minor component of the fatty acids of the milk during lactation, its concentration increased from less than 1 % during early lactation to 1·4 % by the 100th day of lactation.


Reproduction ◽  
2001 ◽  
pp. 881-887 ◽  
Author(s):  
K Retterstol ◽  
TB Haugen ◽  
TN Tran ◽  
BO Christophersen

The essential fatty acid 22:6(n-3) is a minor component of the Western diet, but a major fatty acid in human testis and semen. In mature spermatozoa, the physical and fusogenic properties of the plasma membrane are probably influenced by its particular fatty acid composition. In this study, the synthesis of 22:6(n-3) and 22:5(n-6) was investigated in isolated human testicular cells. [1-(14)C]20:4(n-6), [1-(14)C]20:5(n-3), [1-(14)C]22:4(n-6) and [1-(14)C]22:5(n-3) were incubated in a 'crude' cell suspension (consisting of a mixture of the cells in the seminiferous tubule), and in fractionated pachytene spermatocytes and round spermatids. The esterification of fatty acids in lipid and phospholipid classes and the fatty acid chain elongation and desaturation were measured. The crude cell suspension metabolized the fatty acids more actively than did the fractionated germ cell suspension, indicating that types of cell other than the germ cells are important for fatty acid elongation and desaturation and thus the production of 22:6(n-3). This finding is in agreement with previous results in rats that indicated that the Sertoli cells are the most important type of cell for the metabolism of essential fatty acids in the testis. Some [1-(14)C]20:5(n-3) was elongated to [(14)C]22:5(n-3) in the fractionated germ cells, but very little was elongated further to [(14)C]24:5(n-3),possibly restricting the formation of [(14)C]22:6(n-3). In the fractionated germ cells, the fatty acid substrates were recovered primarily in the phospholipid fraction, indicating an incorporation in the membranes, whereas in the crude cells, more substrates were esterified in the triacylglycerol fraction. In the phospholipids, more radioactivity was recovered in phosphatidylcholine than in phosphatidylethanolamine and more radioactivity was recovered in phosphatidylethanolamine than in phosphatidylinositol or phosphatidylserine.


2021 ◽  
Vol 8 ◽  
Author(s):  
Stefanie M. Colombo ◽  
Mohamed Emam ◽  
Brian C. Peterson ◽  
Jennifer R. Hall ◽  
Gary Burr ◽  
...  

Selection efforts focused on adaptation to plant-based diets, particularly the ability to synthesize polyunsaturated fatty acids (PUFA), are now emerging in aquaculture. Landlocked salmon (Grand Lake population; GL) may differ from the commercial Saint John River (SJR) strain in terms of PUFA metabolism. The objective of this study was to determine if GL salmon can contribute toward broodstock selection for enhanced PUFA synthesis. Two diets containing either fish oil (FO) or plant-based oil (FO-free) were fed to the SJR and GL strains (∼58 g/fish) for 16 weeks. Growth, liver, and muscle fatty acid (FA) content, and transcript expression of lipid metabolism and inflammation-related genes were evaluated. GL salmon fed the FO diet showed reduced growth compared to SJR salmon (fed either diet); however, GL salmon fed the FO-free diet, growth was not significantly different compared to any group. In liver, SJR salmon fed the FO-free diet had higher levels of n-6 PUFAs (21.9%) compared to GL fed the same diet (15.9%); while GL salmon fed the FO-free diet had higher levels of monounsaturated FAs (48.9%) compared with SJR salmon fed the same diet (35.7%). 20:5n-3 and 22:6n-3 were the same in GL and SJR salmon liver and muscle, respectively, fed the FO-free diet. In liver, GL salmon fed the FO-free diet had higher acac and acly compared to all treatments and had higher fasb compared to both strains fed the FO-diet. GL salmon fed the FO-free diet had higher cd36c and fabp3b in liver compared to GL salmon fed the FO diet and SJR salmon fed either diet. GL salmon fed the FO-free diet had higher lect2a and pgds in liver compared to SJR salmon fed the FO-free diet. In muscle, GL salmon fed the FO-free diet had higher fadsd5 and fadsd6b compared with both strains fed the FO diet. These results suggest there is a genetic basis behind the potential for GL salmon to utilize FO-free diets more efficiently than SJR salmon, with regards to FA metabolism.


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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