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Showing papers on "Fatty acid published in 1991"


Journal ArticleDOI
TL;DR: Branched-chain fatty acids of the iso and anteiso series occur in many bacteria as the major acyl constituents of membrane lipids and are an important criterion used to aid identification and classification of bacteria.

1,303 citations


Journal ArticleDOI
01 Feb 1991-Diabetes
TL;DR: It is concluded that the particular fatty acids and the lipid environment in which they are presented in high-fat diets determine insulin sensitivity in rats and impaired insulin action in skeletal muscle relates to triglyceride accumulation, suggesting intracellular glucose–fatty acid cycle involvement.
Abstract: High levels of some but not all dietary fats lead to insulin resistance in rats. The aim of this study was to investigate the important determinants underlying this observation. Insulin action was assessed with the euglycemic clamp. Diets high in saturated, monounsaturated (ω-9), or polyunsaturated (ω-6) fatty acids led to severe insulin resistance; glucose infusion rates [GIR] to maintain euglycemia at ∼1000 pM insulin were 6.2 ± 0.9, 8.9 ± 0.9, and 9.7 ± 0.4 mg · kg −1 · min −1 , respectively, versus 16.1 ± 1.0 mg · kg −1 · min −1 in chow-fed controls. Substituting 11% of fatty acids in the polyunsaturated fat diet with long-chain ω-3 fatty acids from fish oils normalized insulin action (GIR 15.0 ± 1.3 mg · kg −1 · min −1 ). Similar replacement with short-chain ω-3 (α-linolenic acid, 18:3ω3) was ineffective in the polyunsaturated diet (GIR 9.9 ± 0.5 mg · kg −1 · min −1 ) but completely prevented the insulin resistance induced by a saturated-fat diet (GIR 16.0 ± 1.5 mg · kg −1 · min −1 ) and did so in both the liver and peripheral tissues. Insulin sensitivity in skeletal muscle was inversely correlated with mean muscle triglyceride accumulation ( r = 0.95 and 0.86 for soleus and red quadriceps, respectively; both P = 0.01). Furthermore, percentage of long-chain ω-3 fatty acid in phospholipid measured in red quadriceps correlated highly with insulin action in that muscle ( r = 0.97). We conclude that 1 ) the particular fatty acids and the lipid environment in which they are presented in high-fat diets determine insulin sensitivity in rats; 2 ) impaired insulin action in skeletal muscle relates to triglyceride accumulation, suggesting intracellular glucose–fatty acid cycle involvement; and 3 ) long-chain ω-3 fatty acids in phospholipid of skeletal muscle may be important for efficient insulin action.

994 citations


Journal Article
TL;DR: There is a discrepancy between the antioxidant efficacy of CLA and its anticarcinogenic potency, suggesting that some other mechanisms might be involved in cancer protection.
Abstract: Conjugated dienoic derivative of linoleic acid (CLA) is a collective term which refers to a mixture of positional and geometric isomers of linoleic acid. It is a naturally occurring substance in food and is present at higher concentrations in products from animal sources. The present study reports that synthetically prepared CLA is an effective agent in inhibiting the development of mammary tumors induced by dimethylbenz( a )anthracene. Rats were fed either the AIN-76A basal diet or the same diet supplemented with 0.5, 1, or 1.5% CLA by weight. These diets were started 2 weeks before carcinogen administration and continued until the end of the experiment. The total number of mammary adenocarcinomas in the 0.5, 1, and 1.5% CLA groups was reduced by 32, 56, and 60%, respectively. The final tumor incidence and cumulative tumor weight were similarly diminished in rats fed the CLA-containing diets. In general, there appeared to be a dose-dependent protection at levels of 1% CLA and below, but no further beneficial effect was evident at levels above 1%. Chronic feeding of up to 1.5% CLA produced no adverse consequences in the animals. Analysis of the phospholipid fraction from liver and mammary tumor extracts showed that only the c 9, t 11 isomer of CLA was incorporated and that the level of incorporation increased with dietary intake. An interesting property of CLA is its ability to suppress peroxide formation from unsaturated fatty acid in a test-tube model (Cancer Res., Ha et al. 50: 1097–1101, 1990). In view of this information, the amount of thiobarbituric acid-reactive substances (lipid peroxidation products) present endogenously in liver and mammary gland was quantitated. The feeding of CLA (for either 1 or 6 months) resulted in a decrease in the extent of lipid peroxidation in the mammary gland, but such a suppressive effect was not detected in the liver. It should be noted that maximal antioxidant activity was observed with only 0.25% CLA in the diet, whereas maximal tumor inhibition was achieved at about 1% CLA. Hence there is a discrepancy between the antioxidant efficacy of CLA and its anticarcinogenic potency, suggesting that some other mechanisms might be involved in cancer protection. Unlike the stimulatory effect of linoleic acid in carcinogenesis (Cancer Res., Ip et al., 45: 1997–2001, 1985), the reaction of CLA in cancer prevention is specific, and CLA is more powerful than any other fatty acid in modulating tumor development.

790 citations


Journal ArticleDOI
TL;DR: Although (n-3) fatty acid-induced reduction in cytokine production may have beneficial anti-inflammatory effects, its suppression of IL-2 production and lymphocyte proliferation in older women may not be desirable.
Abstract: The effect of (n-3) fatty acid supplementation on cytokine production and lymphocyte proliferation was investigated in young (23-33 y) and older (51-68 y) women. Subjects supplemented their diets with 2.4 g of (n-3) fatty acid/d for 3 mo. Blood was collected before and after 1, 2 and 3 mo of supplementation. The (n-3) fatty acid supplementation reduced total interleukin (IL)-1 beta synthesis by 48% in young women but by 90% in older women; tumor necrosis factor was reduced by 58% in young and 70% in older women. Interleukin-6 was reduced in young women by 30% but by 60% in older women. Older women produced less IL-2 and had lower mitogenic responses to phytohemagglutinin (PHA) than young women prior to (n-3) fatty acid supplementation. The (n-3) fatty acid supplementation reduced IL-2 production in both groups; however, this reduction was significant only in older women. The PHA-stimulated mitogenic response was significantly reduced by (n-3) fatty acid in older women (36%). Thus, long-term (n-3) fatty acid supplementation reduced cytokine production in young women and cytokine production and T cell mitogenesis in older women. The reduction was more dramatic in older women than in young women. Although (n-3) fatty acid-induced reduction in cytokine production may have beneficial anti-inflammatory effects, its suppression of IL-2 production and lymphocyte proliferation in older women may not be desirable.

705 citations


Journal ArticleDOI
TL;DR: Limited evidence indicates frequency of lipid feeding and physical form of oil (free oil vs. oilseed), and heat treatment of oilseeds has relatively little influence on modification of milk fat.

575 citations


Journal ArticleDOI
TL;DR: It is suggested that both the ATP/ADP antiporter and thermogenin facilitate translocation of the fatty anions through the mitochondrial membrane.

436 citations


Journal ArticleDOI
TL;DR: Calculation of overall ATP production from both oxidative and glycolytic sources determined that even in the presence of high concentrations of fatty acids, myocardial triglyceride turnover can provide over 11% of steady state ATP production in the aerobically perfused heart.

397 citations


Journal ArticleDOI
TL;DR: De novo hepatic lipogenesis is a quantitatively minor pathway, consistent with gas exchange estimates; fatty acid futile cycling (oxidation/resynthesis) is not thermogenically significant; and synthesis rates of different nonessential fatty acids by human liver are not identical in nonoverfed normal men.
Abstract: Direct measurement of de novo lipogenesis has not previously been possible in humans. We measured de novo hepatic lipogenesis in normal men by means of stable isotopes and by combining the acetylated-xenobiotic probe technique with mass isotopomer analysis of secreted very low density lipoprotein-fatty acids (VLDL-FA). Sulfamethoxazole (SMX) was administered with [13C]acetate during an overnight fast followed by refeeding with intravenous glucose (7-10 mg/kg of weight per min), oral Ensure (7-10 mg of carbohydrate/kg of weight per min), or a high-carbohydrate mixed-meal breakfast (3.5 g of carbohydrate/kg of weight). Respiratory quotients remained less than 1.0. High-performance liquid chromatography/mass spectrometry-determined enrichments in SMX-acetate attained stable plateau values, and hepatic acetyl-coenzyme A (CoA) dilution rate did not increase with refeeding (approximately 0.024 mmol/kg per min). The fraction of VLDL-palmitate derived from de novo lipogenesis was only 0.91 +/- 0.27% (fasted) and 1.64-1.97% (fed). For stearate, this was 0.37 +/- 0.08% and 0.47-0.64%. Precursor enrichments predicted from isotopomer ratios were close to measured SMX-acetate enrichments, indicating that SMX-acetate samples the true lipogenic acetyl-CoA pool. Stearate synthesis was less than palmitate and the two did not move in parallel. Estimated total VLDL-FA synthesis is less than 500 mg/day. Thus, de novo hepatic lipogenesis is a quantitatively minor pathway, consistent with gas exchange estimates; fatty acid futile cycling (oxidation/resynthesis) is not thermogenically significant; and synthesis rates of different nonessential fatty acids by human liver are not identical in nonoverfed normal men. The contribution and regulation of de novo lipogenesis in other settings can be studied using this technique.

346 citations


Journal ArticleDOI
TL;DR: It is suggested that astrocytes play an important supportive role in the brain by elongating and desaturating ω‐6 and ω-3 essential fatty acid precursors to 20:4ω‐6and 22:6ω‐3, then releasing the long‐chain polyunsaturated fatty acids for uptake by neurons.
Abstract: Elongated, highly polyunsaturated derivatives of linoleic acid (18:2 omega-6) and linolenic acid (18:3 omega-3) accumulate in brain, but their sites of synthesis are not fully characterized. To investigate whether neurons themselves are capable of essential fatty acid elongation and desaturation or are dependent upon the support of other brain cells, primary cultures of rat neurons and astrocytes were incubated with [1-14C] 18:2 omega-6, [1-14C]20:4 omega-6, [1-14C]18:3 omega-3, or [1-14C]20:5 omega-3 and their elongation/desaturation products determined. Neuronal cultures were routinely incapable of producing significant amounts of delta 4-desaturase products. They desaturated fatty acids very poorly at every step of the pathway, producing primarily elongation products of the 18- and 20-carbon precursors. In contrast, astrocytes actively elongated and desaturated the 18- and 20-carbon precursors. The major metabolite of 18:2 omega-6 was 20:4 omega-6, whereas the primary products from 18:3 omega-3 were 20:5 omega-3, 22:5 omega-3, and 22:6 omega-3. The majority of the long-chain fatty acids formed by astrocyte cultures, particularly 20:4 omega-6 and 22:6 omega-3, was released into the extracellular fluid. Although incapable of producing 20:4 omega-6 and 22:6 omega-3 from precursor fatty acids, neuronal cultures readily took up these fatty acids from the medium. These findings suggest that astrocytes play an important supportive role in the brain by elongating and desaturating omega-6 and omega-3 essential fatty acid precursors to 20:4 omega-6 and 22:6 omega-3, then releasing the long-chain polyunsaturated fatty acids for uptake by neurons.

315 citations


Journal ArticleDOI
TL;DR: Ruminal synthesis and biohydrogenation of fatty acids in dairy cows were determined by sampling duodenal digesta through T-cannulas and fatty acids synthesized in greatest amounts were odd or branched chains.

301 citations


Journal ArticleDOI
TL;DR: The result presented herein implies that the receptor-mediated release of unsaturated fatty acids from phospholipids may take part, in synergy with diacylglycerol, in the activation of PKC even when the Ca2+ concentration is low.
Abstract: Kinetic properties of the purified alpha, beta, and gamma subspecies of protein kinase C (PKC) to respond to diacylglycerol, phosphatidylserine (PtdSer), and Ca2+ were reinvestigated in the presence of several fatty acids. Although responses of these enzyme subspecies to the lipids slightly differed from one another, the reaction velocity of these subspecies was significantly enhanced by synergistic action of diacylglycerol and a cis-unsaturated fatty acid. Arachidonic, oleic, linoleic, linolenic, and docosahexaenoic acids were active in this role, whereas saturated fatty acids such as palmitic and stearic acids were inactive. Elaidic acid was also inactive. In the presence of both PtdSer and diacylglycerol, the cis-unsaturated fatty acids increased further an apparent affinity of PKC to Ca2+ and allowed the enzyme to exhibit almost full activation at nearly basal levels of Ca2+ concentration. The concentration of fatty acid giving rise to the maximum activation of enzyme was approximately 20-50 microM. The result presented herein implies that the receptor-mediated release of unsaturated fatty acids from phospholipids may take part, in synergy with diacylglycerol, in the activation of PKC even when the Ca2+ concentration is low. A possibility arises, then, that the activation of PKC is an integral part of the signal-induced degradation cascade of various membrane phospholipids, which is initiated by the actions of phospholipase C and phospholipase A2.

Journal ArticleDOI
TL;DR: The aim of this review is to summarize the current information regarding the remodeling pathways involving predominantly CPG and EPG in various mammalian cells and tissues and focus particularly on the roles played by transacylases as they relate to both donor and acceptor specificities.

Journal ArticleDOI
TL;DR: The results suggest that a significantly reduced amount and/or structural alterations of ceramide 1 deriving from epidermal keratinocytes may be responsible for the impaired water-barrier function of the skin in AD.
Abstract: Patients with atopic dermatitis (AD) often present with a dry skin. To clarify the relationship between dry skin and lipid abnormalities within stratum corneum, stratum corneum lipids were collected from six AD patients aged 15 to 25 years and from sex- and age-matched controls. All major stratum corneum lipid classes were separated and quantitated by high-performance thin-layer chromatography/photodensitometry. Six ceramide fractions were also isolated and quantitated by thin-layer chromatography/photodensitometry. Esterified fatty acids of both ceramide 1 (acylceramides) and wax esters were analysed by capillary gas chromatography. The relative amounts of all the stratum corneum lipid classes including squalene, cholesterol esters, wax esters, triglycerides, free fatty acids, cholesterol, ceramides, cholesterol sulphate and phospholipids did not differ statistically between AD patients and controls. However, a significant decrease in proportion of ceramide 1, which is believed to be a carrier of linoleate responsible for a water-barrier function, and increased levels of esterified C18:1 fatty acids (oleate) of ceramide 1 were observed in AD patients. On the other hand, the fatty acid compositions as well as the proportions of C16:1 straight-chain component in sebum wax esters of AD patients were very similar to those of controls. These results suggest that a significantly reduced amount and/or structural alterations of ceramide 1 deriving from epidermal keratinocytes may be responsible for the impaired water-barrier function of the skin in AD.

Journal ArticleDOI
TL;DR: Peroxisomal beta-oxidation in rat liver is characterized by a high extent of induction following exposure of rats to a variety of amphipathic compounds possessing a carboxylic-, or sulphonic acid group, and recent findings of the involvement of a member of the steroid hormone receptor superfamily during induction suggest that induction of peroxisome beta-Oxidation represents another regulatory phenomenon controlled by nuclear receptor proteins.

Journal ArticleDOI
TL;DR: Eating quality traits were generally improved as the concentration of mono-unsaturated fatty acids increased and poly-uns saturated fatty acids decreased and the rate of change in fatty acid concentrations was greater in Landrace pigs than in Duroc pigs.

Journal ArticleDOI
TL;DR: In the frontal cortex of schizophrenic patients there are significant differences from normal in the fatty acid composition of phosphatidylethanolamine, but these differences were not found in the cerebellar cortex.

Journal ArticleDOI
TL;DR: A scheme of ricinoleate formation and its incorporation into triacylglycerols in castor-bean endosperm is proposed, based on the results of microsomal membrane preparations from the developingendosperm of castor bean.
Abstract: Microsomal membrane preparations from the developing endosperm of castor bean (Ricinus communis) catalysed the transfer of oleate from [14C]oleoyl-CoA to phosphatidylcholine (PtdCho). In the presence of NADH, radioactive ricinoleate (12-hydroxyoctadec-9-enoate) was synthesized from [14C]oleate, and this was largely recovered in PtdCho and as free fatty acid. The addition of unlabelled ricinoleoyl-CoA to these incubation mixtures did not increase the low [14C]ricinoleate concentration found in the acyl-CoA fraction nor decrease the [14C]ricinoleate concentration in PtdCho and free fatty acid, and thus no evidence was obtained for a hydroxylation with oleoyl-CoA as a substrate. The addition of NADH, necessary for the formation of ricinoleate, caused a decrease of the total radioactivity in PtdCho with a corresponding increase in the amount of label in free ricinoleic acid. This increase was due to the action of a phospholipase A, which released ricinoleic acid but not oleic acid from PtdCho. Such a phospholipase activity, attacking ricinoleoyl-PtdCho but not oleoyl-PtdCho, was also demonstrated in microsomal preparations from developing cotyledons of safflower and oil-seed rape. An analysis of the acyl groups at different positions in microsomal PtdCho of castor bean showed that ricinoleate was almost entirely associated with position sn-2. Likewise the [14C]ricinoleate in [14C]PtdCho formed after incubations with microsomal preparations with NADH and [14C]oleoyl-CoA resided in position sn-2 with none in position sn-1. In contrast, the [14C]linoleate formed by desaturation of [14C]oleoyl-PtdCho was present at both positions. In the presence of ATP, CoA and Mg2+, the ricinoleate acid released from PtdCho was activated to ricinoleoyl-CoA. The ricinoleoyl-CoA was an efficient acyl donor in the acylation of glycerol 3-phosphate (Gro3P) to yield phosphatidic acid and triacylglycerols. In microsomal preparations incubated with an equimolar mixture of [14C]oleoyl-CoA and [14C]ricinoleoyl-CoA in the presence of Gro3P, only a minor amount of [14C]ricinoleate entered PtdCho, and this was believed to be via the exchange of phosphocholine groups between a diacylglycerol pool and the PtdCho. On the basis of our results, a scheme of ricinoleate formation and its incorporation into triacylglycerols in castor-bean endosperm is proposed.

Journal ArticleDOI
TL;DR: It is concluded that fatty acids or fatty acid metabolites activate the aP2 gene and subsequently modulate its expression and the role of fatty acids in the regulation of adipose-related genes is investigated.

Journal ArticleDOI
TL;DR: In this paper, the location of double bonds in polyunsaturated fatty acids is determined by gas chromatography-mass spectrometry after 4,4-dimethyloxazoline (DMOX) derivatization.

Journal Article
TL;DR: Results suggest that EPA as the pure fatty acid should be considered for clinical investigation as both an anticachectic and antitumor agent, since prior work has shown that the other major component of fish oil docosahexaenoic acid is without pharmacological activity in this system.
Abstract: The effect of the polyunsaturated fatty acids eicosapentaenoic acid (EPA) and gamma-linolenic acid (GLA) on host body weight loss and tumor growth has been investigated in mice bearing a cachexia-inducing colon adenocarcinoma, the MAC16. EPA effectively inhibited both host weight loss and tumor growth rate in a dose-related manner with optimal effects being observed at a dose level of 1.25 to 2.5 g/kg. At these concentrations host body weight was effectively maintained, and there was a delay in the progression of growth of the tumor, such that overall survival was approximately doubled in EPA-treated animals, using the criteria dictated by the United Kingdom Coordinating Committee for the welfare of animals with neoplasms. Even when tumor growth resumed, weight loss did not occur. Animals bearing the MAC16 tumor showed a decreased protein synthesis and an increased degradation in skeletal muscle. Treatment with EPA significantly reduced protein degradation without an effect on protein synthesis. The effect of GLA on both host body weight loss and tumor growth was much less pronounced than that of EPA, with an effect only being seen at a dose of 5 g/kg, at which some toxicity was observed. In vitro studies showed that while EPA was effective in inhibiting tumor-induced lipolysis, GLA was ineffective in this respect. However, prostaglandin E1, which is formed from GLA in vivo, showed partial reversal of tumor-induced lipolysis and probably accounted for the anticachectic effect of GLA. These results suggest that EPA as the pure fatty acid should be considered for clinical investigation as both an anticachectic and antitumor agent, since prior work has shown that the other major component of fish oil docosahexaenoic acid is without pharmacological activity in this system.

Journal ArticleDOI
TL;DR: Electrospray mass spectrometric analysis of mixtures containing monoglycerides, diglycerides, and triglycerides revealed that acylglycerols that contained unsaturated fatty acid chains were observed to exhibit a response in the mass spectrum greater than those with saturated chains, and ion signals resulting from the molecular adduct ions of monoglycersides were more abundant than those of diglyceride, which were more scarce in themass spectrum.
Abstract: This paper presents electrospray mass spectrometric analysis of mixtures containing monoglycerides, diglycerides, and triglycerides. Sample compounds were dissolved in concentrations of 1-50 pmol/microL in chloroform:methanol (70:30, v:v), which was modified by the addition of alkall-metal or ammonium salts or by addition of formic acid to favor the addition of a cationic species to the sample molecules. Electrospray mass spectrometric analysis of acylglycerol standards yielded positive-ion current signals for (M + Na)+ or (M + NH4)+ of all the species that were present at low picomole per microliter concentrations with no fragmentation. For equimolar concentrations of these sample compounds, there was a general decrease in ion current response as the analyte polarity decreased. Therefore, acylglycerols that contained unsaturated fatty acid chains were observed to exhibit a response in the mass spectrum greater than those with saturated chains, and ion signals resulting from the molecular adduct ions of monoglycerides were more abundant than those of diglycerides, which were more abundant than those of triglycerides in the mass spectrum. Electrospray mass spectrometric analysis of an unknown lipid material recovered from a mammalian cell culture reactor revealed a mixture of triglycerides containing mostly C14, C16, and C18 fatty acids with varying degrees of unsaturation. The results obtained by electrospray mass spectrometry compared favorably to those obtained by gas chromatography after saponification and methylation of fatty acid components of the triglycerides. MS/MS fragmentation of sodiated acylglycerols required a dissociation energy significantly greater than that required for fragmentation of ammoniated acylglycerols, so MS/MS characterization of acylglycerols was generally performed on the ammoniated compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: The total protein, carbohydrate, lipid and ash compositions, and fatty acid contents of two species of marine microalgae, the eustigmatophyte Nannochloropsis oculata and the chrysophyte Isochrysis sp.
Abstract: The total protein, carbohydrate, lipid and ash compositions, and fatty acid contents of two species of marine microalgae, the eustigmatophyte Nannochloropsis oculata (formerly ‘Chlorella sp., Japan’) and the chrysophyte Isochrysis sp. (Tahitian) used in tropical Australian mariculture, were studied. The microalgae were grown under a range of culture conditions (41 and 601 laboratory culture, 3001 bag culture, and 80001 outdoor culture) and four light regimes (100 to 107 µ E m−2 s−1, 240 to 390 µ E m−2 s−1, 340 to 620 µ E m−2 s−1, and 1100 to 1200 µE m−2 s−1 respectively) to determine the effect of light intensity on the chemical composition of large scale outdoor cultures. Laboratory and bag cultures were axenic and cultured in Walne medium while outdoor cultures were grown in a commercial medium designed for optimum nutrition in tropical outdoor aquaculture operations. Change in growth medium and photon flux density produced only small changes in the proximate biochemical composition of both algae. N. oculata and Isochrysis sp. both showed a trend towards slightly lower carbohydrate and higher chlorophyll a in shaded outdoor culture. Isochrysis sp. showed significant concentrations of the essential polyunsaturated fatty acid 22:6(n−3) (docosahexaenoic acid) from 5.3 to 10.3% of total fatty acid, and 20:5(n−3) (eicosapentaenoic acid) ranged from 0.6 to 4.1%. In contrast, N. oculata had high concentrations of 20:5(n−3) (17.8 to 39.9%) and only traces of 22:6(n−3). The fatty acid composition of Isochrysis sp. grown at high photon flux density (1100–1200 µE m−2 s−1) under outdoor culture showed a decrease in the percentage of several highly unsaturated fatty acids, including 20:5(n−3), and an increase in 22:6(n−3). N. oculata showed a similar decrease in the percentage of 20:5(n−3). High light intensity caused a decrease in the ratio of total C16 unsaturated fatty acids to saturated 16:0 in N. oculata, and a decrease in the ratio of total C18 unsaturated fatty acids to saturated 18:0 together with a decrease in the ratio of total unsaturated fatty acids to total saturated fatty acids in both microalgae.

Journal ArticleDOI
TL;DR: The results demonstrate that the fatty acid composition and lipid content of heterotrophically-grown microalgae can be favourably manipulated by varying culture conditions.
Abstract: The effect of the carbon to nitrogen (C/N) ratio of the medium and the aeration rate on the lipid content and fatty acid composition ofChlorella sorokiniana was investigated using heterotrophic, batch culture. Both parameters had a significant effect. A C/N ratio of approximately 20, was found to indicate a change from carbon to nitrogen limitation forC. sorokiniana. Cell lipid content was at a minimum at this value and increased at both higher and lower C/N values. Low C/N ratios favoured a high proportion of trienoic fatty acids at the expense of monoenoic acids. Aeration enhanced cell growth, fatty acid yield and the synthesis of unsaturated dienoic and trienoic fatty acids, but reduced cell lipid content. The results demonstrate that the fatty acid composition and lipid content of heterotrophically-grown microalgae can be favourably manipulated by varying culture conditions.

Journal ArticleDOI
TL;DR: The omega-3 fatty acid content of eggs from hens fed flax and canola seed increased significantly and brain tissues of embryos at 15, 17, and 19 days of incubation and on newly hatched chicks were analyzed.

Journal ArticleDOI
TL;DR: Digestibility of commercial fat supplements was determined in two experiments with high (59% of diet DM) forage diets and there were no differences among fat sources in fatty acid digestibility.

Journal ArticleDOI
TL;DR: The results indicate that acetoacetate is primarily formed either by the action of 3‐oxo‐acid‐CoA transferase (EC 2.8.3.5) or aceto acetyl‐ CoA deacylase ( EC 3.1.2.5), which was barely measurable, and not by theaction of the mitochondrial HMG‐coA cycle involving HMG­CoA lyase (ec 4.1‐14C‐, 4.3
Abstract: The oxidation of the fatty acids octanoate and palmitate to CO2 and the ketone bodies acetoacetate and D-(-)-3-hydroxybutyrate was examined in astrocytes that were prepared from cortex of 2-day-old rat brain and grown in primary culture to confluence. Accumulation of acetoacetate (by mass) in the culture medium of astrocytes incubated with octanoate (0.3-0.5 mM) was 50-90 nmol C2 units h-1 mg of protein-1. A similar rate was obtained using radiolabeled tracer methodology with [1-14C]octanoate as labeled substrate. The results from the radiolabeled tracer studies using [1-14C]- and [7-14C]octanoate and [1-14C]-, [13-14C]-, and [15-14C]palmitate indicated that a substantial proportion of the omega-terminal four-carbon unit of these fatty acids bypassed the beta-ketothiolase step of the beta-oxidation pathway and the 3-hydroxy-3-methylglutaryl (HMG)-CoA cycle of the classic ketogenic pathway. The [14C]acetoacetate formed from the 1-14C-labeled fatty acids, obligated to pass through the acetyl-CoA pool, contained 50% of the label at carbon 3 and 50% at carbon 1. By contrast, the [14C]acetoacetate formed from (omega-1)-labeled fatty acids contained 90% of the label at carbon 3 and 10% at carbon 1, whereas that formed from the (omega-3)-labeled fatty acid contained 20% of the label at carbon 3 and 80% at carbon 1. These results indicate that acetoacetate is primarily formed either by the action of 3-oxo-acid-CoA transferase (EC 2.8.3.5) or acetoacetyl-CoA deacylase (EC 3.1.2.11) or both on acetoacetyl-CoA and not by the action of the mitochondrial HMG-CoA cycle involving HMG-CoA lyase (EC 4.1.3.4), which was readily detected, and HMG-CoA synthase (EC 4.1.3.5), which was barely measurable.

Journal ArticleDOI
TL;DR: It is established that a diet with a low (n-3)/(n-6) ratio can cause changes in fatty acid metabolism that are deleterious to the health of salmonid fish, especially when subjected to stress.
Abstract: For 16 wk Atlantic salmon (Salmo salar) post-smolts were fed practical-type diets that contained either fish oil (FO) or sunflower oil (SO) as the lipid component. Both diets contained adequate (n-3) polyunsaturated fatty acids (PUFA). All the phospholipids of heart and liver from SO-fed fish had increased levels of 18:2(n-6), 20:2(n-6) and 20:3(n-6); phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) also had increased 20:4(n-6). There was a general decrease in 20:5(n-3) in the phospholipids, reflected in an increase in the 20:4(n-6)/20:5(n-3) ratio, especially in PC and PE. The fatty acid compositions of phospholipids from brain and retina were much less affected by dietary linoleate than those of heart and liver. Fish fed SO developed severe heart lesions that caused thinning of the ventricular wall and muscle necrosis. The fish fed SO also were susceptible to a transportation-induced shock syndrome that caused 30% mortality. These results establish that a diet with a low (n-3)/(n-6) ratio can cause changes in fatty acid metabolism that are deleterious to the health of salmonid fish, especially when subjected to stress.

Journal ArticleDOI
TL;DR: The changes seen in phospholipid profiles suggest a significant transfer of omega 3 and omega 6 polyunsaturated FA from the mother to the fetus, which are essential for normal fetal growth and development.
Abstract: In a group of 19 normal pregnant women, plasma lipids were extracted, phospholipids were isolated, and the fatty acid (FA) compositions were measured by capillary gas chromatography. Blood samples were taken at 36 wk, at labor, and at 6 wk postpartum. The FA profiles showed deficiencies of omega 6 and omega 3 FA (omega indicating the length of the terminal saturated chain), the latter more severe, at all three times. Mean melting point (MMP) was calculated for each sample as an index of "fluidity" based upon all FA present. MMP varied linearly with total polyunsaturated FA and with double bond index, current measures of "fluidity" and essential FA status. MMP was elevated 9-11 degrees C in plasma phospholipids of women during pregnancy and labor and postpartum. Lactating mothers showed less recovery from the deficiencies than did the nonlactating mothers, but neither approached normal at 6 wk. The changes seen in phospholipid profiles suggest a significant transfer of omega 3 and omega 6 polyunsaturated FA from the mother to the fetus. These FA are essential for normal fetal growth and development; their relative deficiency in maternal circulation suggests that dietary supplementation may be indicated.

Journal ArticleDOI
TL;DR: It is demonstrated that HOO, generated either chemically (KO2) or enzymatically (xanthine oxidase), is a good initiator of fatty acid peroxidation in linoleic acid ethanol/water dispersions; O2- serves only as the source of HOO.

Patent
25 Sep 1991
TL;DR: In this paper, polyhydroxy fatty acid amide materials are prepared from reactants such as N-methylglucamine and fatty acid esters in the presence of hydroxy solvents.
Abstract: Polyhydroxy fatty acid amide materials are prepared from reactants such as N-methylglucamine and fatty acid esters in the presence of hydroxy solvents. Polyhydroxy fatty acid amide detersive surfactants are secured. By-product and color formation are minimized.