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1.
Two relatively rare fatty acids, γ-linolenic acid (GLA) and stearidonic acid (STA), have attracted much interest due to their nutraceutical and pharmaceutical potential. STA, in particular, has been considered a valuable alternative source for omega-3 fatty acids due to its enhanced conversion efficiency in animals to eicosapentaenoic acid when compared with the more widely consumed omega-3 fatty acid, α-linolenic acid (ALA), present in most vegetable oils. Exploiting the wealth of information currently available on in planta oil biosynthesis and coupling this information with the tool of genetic engineering it is now feasible to deliberately perturb fatty acid pools to generate unique oils in commodity crops. In an attempt to maximize the STA content of soybean oil, a borage Δ6 desaturase and an Arabidopsis Δ15 desaturase were pyramided by either sexual crossing of transgenic events, re-transformation of a Δ6 desaturase event with the Δ15 desaturase or co-transformation of both desaturases. Expression of both desaturases in this study was under the control of the seed-specific soybean β-conglycinin promoter. Soybean events that carried only the Δ15 desaturase possessed a significant elevation of ALA content, while events with both desaturases displayed a relative STA abundance greater than 29%, creating a soybean with omega-3 fatty acids representing over 60% of the fatty acid profile. Analyses of the membrane lipids in a subset of the transgenic events suggest that soybean seeds compensate for enhanced production of polyunsaturated fatty acids by increasing the relative content of palmitic acid in phosphatidylcholine and other phospholipids. 相似文献
2.
The present study was conducted to investigate the effect of zinc deficiency on fatty acid desaturation in rats fed two different
types of dietary fat, a mixture of coconut oil and safflower oil (7∶1, w/w, “coconut oil diet”) or linseed oil (“linseed oil
diet”). In order to ensure an adequate food intake, all rats were force-fed by gastric tube. Zinc deficiency caused statistical
significant reducion of Δ9-desaturase activity in liver microsomes of rats fed coconut oil diet and tendencial reduction (p<0.15) in rats fed linseed oil diet compared with control rats fed diets with the same type of fat. In agreement with this
effect, zinc deficiency in the rats fed both types of dietary fat increased the ratio between total saturated and total monounsaturated
fatty in liver phospholipids and liver microsomes. Zinc deficient rats on the coconut oil diet had unchanged Δ6-desaturase
activity with linoleic acid as substrate and lowered activity with α-linolenic acid as substrate. In contrast, zinc deficient
rats on the linseed oil diet had increased Δ6-desaturase activity with linoleic acid as substrate and unchanged activity with
α-linolenic acid. Because linoleic acid is the main substrate for Δ6-desaturase in the rats fed coconut oil diet, and α-linolenic
acid is the main substrate in the rats fed linseed oil diet, it is concluded that in vivo Δ6-desaturation was not changed
by zinc deficiency in the rats fed both types of dietary fat. Activity of Δ5-desaturase was also not changed by zinc deficiency
in the rats fed both dietary fats. Levels of fatty acids in liver phospholipids and microsomes derived by Δ4-, Δ5-, and Δ6-desaturation
were not consistently changed by zinc deficiency in the rats fed both types of dietary fat. Thus, the enzyme studies and also
fatty acid composition data of liver phospholipids and microsomes indicate that zinc deficiency does not considerably disturb
desaturation of linoleic and α-linolenic acid. Therefore, it is suggested that similarities between deficiencies of zinc and
essential fatty acids described in literature are not due to disturbed desaturation of linoleic acid in zinc deficiency. The
present study also indicates that zinc deficiency enhances incorporation of eicosapentaenoic acid into phosphatidylcholine
of rats fed diets with large amounts ofn-3 polyunsaturated fatty acids. 相似文献
3.
cDNA clones encoding cytochrome b5 fusion desaturases were isolated from Primula cortusoides L. and Primula luteola Ruprecht, species previously shown to preferentially accumulate either n−6 or n−3 Δ6-desaturated fatty acids, respectively. Functional characterisation of these desaturases in yeast revealed that the recombinant Primula enzymes displayed substrate preferences, resulting in the predominant synthesis of either γ-linolenic acid (n−6) or stearidonic acid (n−3). Independent expression of the two Primula desaturases in transgenic Arabidopsis thaliana confirmed these results, with γ-linolenic acid and stearidonic acid accumulating in both leaf and seed tissues to different levels, depending on the substrate specificity of the desaturase. Targeted lipid analysis of transgenic Arabidopsis lines revealed the presence of Δ6-desaturated fatty acids in the acyl-CoA pools of leaf but not seed tissue. The implications for the transgenic synthesis of C20 polyunsaturated fatty acids via the elongation of Δ6-desaturated fatty acids are discussed, as is the potential of using Primula desaturases in the synthesis of C18
n−3 polyunsaturated fatty acids such as stearidonic acid. 相似文献
4.
Interactions of saturated, n-6 and n-3 polyunsaturated fatty acids to modulate arachidonic acid metabolism 总被引:6,自引:0,他引:6
Anti-thrombotic effects of omega-3 (n-3) fatty acids are believed to be due to their ability to reduce arachidonic acid levels. Therefore, weanling rats were fed n-3 acids in the form of linseed oil (18:3n-3) or fish oil (containing 20:5n-3 and 22:6n-3) in diets containing high levels of either saturated fatty acids (hydrogenated beef tallow) or high levels of linoleic acid (safflower oil) for 4 weeks. The effect of diet on the rate-limiting enzyme of arachidonic acid biosynthesis (delta 6-desaturase) and on the lipid composition of hepatic microsomal membrane was determined. Both linseed oil- or fish oil-containing diets inhibited conversion of linoleic acid to gamma-linolenic acid. Inhibition was greater with fish oil than with linseed oil, only when fed with saturated fat. delta 6-Desaturase activity was not affected when n-3 fatty acids were fed with high levels of n-6 fatty acids. Arachidonic acid content of serum lipids and hepatic microsomal phospholipids was lower when n-3 fatty acids were fed in combination with beef tallow but not when fed with safflower oil. Similarly, n-3 fatty acids (18:3n-3, 20:5n-3, 22:5n-3, and 22:6n-3) accumulated to a greater extent when n-3 fatty acids were fed with beef tallow than with safflower oil. These observations indicate that the efficacy of n-3 fatty acids in reducing arachidonic acid level is dependent on the linoleic acid to saturated fatty acid ratio of the diet consumed. 相似文献
5.
The plant family Boraginaceae is known to produce a set of unusual fatty acids in the seed oils. In this study, the fatty acid, tocopherol, tocotrienol and plasto-chromanol-8 contents of some Onosma species ( Onosma sericeum, O. armeniacum and O. polioxanthum ) all belonging to sect. Onosma, Anchusa leptophylla subsp. leptophylla, Alkanna froedini and Paracaryum stenophyllum were determined. Some of the studied species are endemic for Turkey. While oleic, linoleic and alpha linolenic acid are the highest as usual fatty acids, gamma linolenic and stearidonic acids are more variable unusual fatty acids in studied genera patterns and the relative concentrations some of these fatty acids and partly also the tocochromanols in Boraginaceae seed oils are suggested to have chemotaxonomic value in this family. In particular, the presence or absence of chain elongation to erucic acid (22:1) and the presence or absence of Δ6-methylene-interrupted polyenoic acids such as γ-linolenic and stearidonic acid are determined and marked as indicators of taxonomic relationship. 相似文献
6.
The present study deals with the production of structured lipid containing omega-3 and omega-6 fatty acids in the ratio of 1:1 by incorporating omega-3 fatty acids (α-linolenic acid) from linseed oil into groundnut oil using lipase (Lipozyme IM from Rhizomucor miehei) catalyzed acidolysis reaction in hexane. The reaction conditions were optimized by response surface methodology with a four-variable five-level central composite rotatable experimental design. The influence of four independent parameters, namely ratio of fatty acid concentrate from linseed to groundnut oil (0.66–1.98, w/w), reaction temperature (30–60 °C), enzyme concentration (1–5%) and reaction time (2–54 h) on omega-3 fatty acids incorporation into groundnut oil were optimized. Optimal conditions for the structured lipid containing omega-3 to omega-6 fatty acids in the ratio of 1:1 were determined to be; enzyme concentration 3.75% (w/w), temperature 37.5 °C, incubation time 30.81 h and ratio of free fatty acid concentrate from linseed oil to groundnut oil 1.16 (w/w). 相似文献
7.
Shenghe Huang Ruijie Liu Yiding Niu Agula Hasi 《Russian Journal of Plant Physiology》2010,57(4):568-573
8.
Modification of fatty acid composition in tomato (Lycopersicon esculentum) by expression of a borage delta6-desaturase 总被引:2,自引:0,他引:2
The improvement of nutritional quality is one potential application for the genetic modification of plants. One possible target
for such manipulation is the modification of fatty acid metabolism. In this work, expression of a borage Δ6-desaturase cDNA in tomato (Lycopersicon esculentum L.) has been shown to produce γ-linolenic acid (GLA; 18:3 Δ6,9,12) and octadecatetraenoic acid (OTA; 18:4 Δ6,9,12,15) in transgenic leaf and fruit tissue. This genetic modification has also, unexpectedly, resulted in a reduction in the percentage
of linoleic acid (LA 18:2 Δ9,12) and a concomitant increase in the percentage of α-linolenic acid (ALA; 18:3 Δ9,12,15) in fruit tissue. These changes in fatty acid composition are thought to be beneficial for human health. 相似文献
9.
The open reading frame of the Δ6-desaturase gene was isolated from Mortierella alpina W15 and the gene was cloned into a pPIC3.5K vector. The vector was transformed into Pichia pastoris GS115 and expression was induced with methanol. The Δ6-desaturase expressed in P. pastoris GS115 catalyzed the conversion of linoleic acid to γ-linolenic acid but not the conversion of α-linolenic acid to octadecatetraenoic
acid. The results indicate that the Δ6-desaturase gene from M. alpina W15 has substrate specificity in different organisms. Phylogenetic analysis revealed that Δ6-desaturase genes can be divided into four monophyletic groups. This work paves the way for further study of the functions
of Δ6-desaturase in fatty acid metabolism and its three-dimensional structure. 相似文献
10.
Tomoko Yoshino Natsumi Kakunaka Yue Liang Yasuhito Ito Yoshiaki Maeda Tatsuhiro Nomaguchi Tadashi Matsunaga Tsuyoshi Tanaka 《Applied microbiology and biotechnology》2017,101(18):6899-6905
Omega-3 fatty acids (ω3 FAs) have attracted attention because they have various health benefits for humans. Fish oils are currently major sources of ω3 FAs, but a sustainable supply of ω3 FAs based on fish oils is problematic because of the increasing demand. In this study, the production potential of a genetically engineered marine cyanobacterium, Synechococcus sp. strain NKBG 15041c, was examined as an alternative source of ω3 FAs. A change in fatty acid composition of this cyanobacterium was successfully induced by the expression of a heterologous Δ6-desaturase, and the transformants synthesized stearidonic acid, which the wild type cannot produce. As a result of optimization of culture conditions, maximal contents of stearidonic acid and total ω3 FAs reached 12.2 ± 2.4 and 118.1 ± 3.5 mg/g, respectively. The maximal ω3 FA productivity was 4.6 ± 0.7 mg/(L⋅day). These are the highest values of the contents of stearidonic acid and ω3 FAs in genetically engineered cyanobacteria reported thus far. Therefore, genetically engineered Synechococcus sp. strain NKBG 15041c may be a promising sustainable source of ω3 fatty acids. 相似文献
11.
The n – 3 polyunsaturated fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have important nutritional benefits in humans. Farmed fish could serve as promising sources of EPA/DHA, but they need these fatty acids or their precursors in their diets. Here we transferred masu salmon 6-desaturase-like gene in zebrafish to increase its ability for synthesizing EPA and DHA. Expression of this gene in transgenic fish elevated their EPA content by 1.4-fold and DHA by 2.1-fold. On the other hand, the -linolenic acid (ALA) content decreased, it being a substrate of 6-desaturase, while the total lipid remained constant. This achievement demonstrates that fatty acid metabolic pathway in fish can be modified by the transgenic technique, and perhaps this could be applied to tailor farmed fish as even better sources of valuable human food. 相似文献
12.
The γ-linolenic acid-producing fungus Mortierella isabellina 6-22 is an important industrial strain. To clarify the biosynthetic pathways for polyunsaturated fatty acids in this strain,
a disruption vector pD4MI6, including 5′ and 3′ regions of the fatty acid Δ6-desaturase open reading frame as homologous recombination elements and the Escherichia coli hygromycin B (HmB) phosphotransferase gene (hph) as selectable marker, was successfully constructed. Following transformation of pD4MI6 into the hygromycin B-sensitive recipient
strain M. isabellina 6-22-4, a Δ6-desaturase gene-defective mutant strain was selected that was unable to produce γ-linolenic acid as determined by gas chromatography
and molecular analysis. The morphology and physiology of the mutant, such as colony shape, color, and growth rate, were changed
dramatically compared with that of strain M. isabellina 6-22-4. 相似文献
13.
James R. Petrie Qing Liu Anne M. Mackenzie Pushkar Shrestha Maged P. Mansour Stan S. Robert Dion F. Frampton Susan I. Blackburn Peter D. Nichols Surinder P. Singh 《Marine biotechnology (New York, N.Y.)》2010,12(4):430-438
The production of long-chain polyunsaturated fatty acids from precursor molecules linoleic acid (LA; 18:2ω6) and α-linolenic
acid (ALA; 18:3ω3) is catalysed by sequential desaturase and elongase reactions. We report the isolation of a front-end Δ6-desaturase
gene from the microalgae Ostreococcus lucimarinus and two elongase genes, a Δ6-elongase and a Δ5-elongase, from the microalga Pyramimonas cordata. These enzymes efficiently convert their respective substrates when transformed in yeast (39–75% conversion for ω3 substrate
fatty acids), and the Δ5-elongase in particular displays higher elongation efficiency (75% for conversion of eicosapentaenoic
acid (20:5ω3) to docosapentaenoic acid (22:5ω3)) than previously reported genes. In addition, the Δ6-desaturase is homologous
with acyl-CoA desaturases and shows a strong preference for the ω3 substrate ALA. 相似文献
14.
The omega-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA, 22:6n-3) has been previously shown to facilitate some of the vital functions of astrocytes. Since some dietary oils contain alpha-linolenic acid (ALA, 18:3n-3), which is a precursor of DHA, we examined their effect on astrocyte development. Fatty acids (FAs) were isolated from commonly used oils and their compositions were determined by GLC. FAs from three oils, viz. coconut, mustard and linseed were studied for their effect on astrocyte morphology. Parallel studies were conducted with FAs from the same oils after heating for 72 h. Unlike coconut oil, FAs from mustard and linseed, both heated and raw, caused significant morphogenesis of astrocytes in culture. ss-AR binding was also substantially increased in astrocytes treated with FAs from raw mustard and linseed oils as compared to astrocytes grown in normal medium. The expression profile of the isoforms of GFAP showed that astrocyte maturation by FAs of mustard and linseed oil was associated with appearance of acidic variants of GFAP and disappearance of some neutral isoforms similar to that observed in cultures grown in serum containing medium or in the presence of DHA. Taken together, the study highlights the contribution of specific dietary oils in facilitating astrocyte development that can have potential impact on human health. 相似文献
15.
Takashi Ide Hideyuki Kobayashi Lakshmikuttyamma Ashakumary Isabelle A. Rouyer Yoko Takahashi Toshifumi Aoyama Takashi Hashimoto Michinao Mizugaki 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2000,1485(1):23-35
The activity and mRNA level of hepatic enzymes in fatty acid oxidation and synthesis were compared in rats fed diets containing either 15% saturated fat (palm oil), safflower oil rich in linoleic acid, perilla oil rich in α-linolenic acid or fish oil rich in eicosapentaenoic (EPA) and docosahexaenoic acids (DHA) for 15 days. The mitochondrial fatty acid oxidation rate was 50% higher in rats fed perilla and fish oils than in the other groups. Perilla and fish oils compared to palm and safflower oils approximately doubled and more than tripled, respectively, peroxisomal fatty acid oxidation rate. Compared to palm and safflower oil, both perilla and fish oils caused a 50% increase in carnitine palmitoyltransferase I activity. Dietary fats rich in n-3 fatty acids also increased the activity of other fatty acid oxidation enzymes except for 3-hydroxyacyl-CoA dehydrogenase. The extent of the increase was greater with fish oil than with perilla oil. Interestingly, both perilla and fish oils decreased the activity of 3-hydroxyacyl-CoA dehydrogenase measured using short- and medium-chain substrates. Compared to palm and safflower oils, perilla and fish oils increased the mRNA level of many mitochondrial and peroxisomal enzymes. Increases were generally greater with fish oil than with perilla oil. Fatty acid synthase, glucose-6-phosphate dehydrogenase, and pyruvate kinase activity and mRNA level were higher in rats fed palm oil than in the other groups. Among rats fed polyunsaturated fats, activities and mRNA levels of these enzymes were lower in rats fed fish oil than in the animals fed perilla and safflower oils. The values were comparable between the latter two groups. Safflower and fish oils but not perilla oil, compared to palm oil, also decreased malic enzyme activity and mRNA level. Examination of the fatty acid composition of hepatic phospholipid indicated that dietary α-linolenic acid is effectively desaturated and elongated to form EPA and DHA. Dietary perilla oil and fish oil therefore exert similar physiological activity in modulating hepatic fatty acid oxidation, but these dietary fats considerably differ in affecting fatty acid synthesis. 相似文献
16.
Biswajit Das Lily Goswami Sudipta Ray Shilpi Ghosh Sanghamitra Bhattacharyya Sampa Das Arun Lahiri Majumder 《Plant Cell, Tissue and Organ Culture》2006,86(2):219-231
Genetic manipulation of the oil-yielding crop plants for better oil quality through biotechnological methods is an important aspect of crop improvement. Due to the inherent absence of the Δ6-desaturase (d6D) function, Brassica juncea, an oil-yielding crop plant, is unable to synthesize γ-linolenic acid (GLA), a nutritionally important fatty acid although the crop plant synthesizes the precursor fatty acids required for GLA production. Cyanobacterial d6D introduces carbon–carbon double bond onto linoleic acid (C18:2) and α-linolenic acid (C18:3) by desaturation processes for production of GLA and octadecatetraenoic acid (OTA) respectively. In the present investigation, d6D coding sequence from Synechocystis sp. PCC6803 was cloned by polymerase chain reaction and introduced into B. juncea through Agrobacterium-mediated transformation technique. Both cytosolic as well as seed-specific expression of d6D were attempted. The transformed plants show production of GLA and OTA in contrast to their absence in the untransformed control plants adducing evidence for introgression and functional expression of the cyanobacterial d6D gene in B. juncea. 相似文献
17.
Omega-3 fatty acids increase the arachidonic acid content of liver cholesterol ester and plasma triacylglycerol fractions in the rat. 总被引:1,自引:0,他引:1
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Recent studies have demonstrated that dietary fish oils rich in eicosapentaenoic acid (C20:5,omega 3) lower the content of arachidonic acid and its metabolites in plasma and tissue phospholipids. The present study examined the fatty acid composition of cholesterol ester and triacylglycerol fractions from plasma and livers of rats fed diets enriched with saturated fatty acids (beef tallow), alpha-linolenic acid (linseed oil) or eicosapentaenoic acid (fish oil). Feeding diets containing linseed oil or fish oil for 28 days increased arachidonic acid (C20:4,omega 6) levels in the cholesterol ester fraction of liver and in the triacylglycerol fraction of the plasma lipids. Plasma cholesterol esters were depleted of C20:4,omega 6 after feeding of the diet containing either linseed oil or fish oil. The changes in C20:4,omega 6 content cannot be explained by alterations in cholesterol ester or triacylglycerol pools of plasma and liver. These results suggest that the decrease in phospholipid C20:4,omega 6 content generally observed after fish oil consumption may be partly due to a shift of C20:4,omega 6 from phospholipid to the triacylglycerol and/or cholesterol ester pools in the same tissue. Triacylglycerols and cholesterol esters may therefore play a buffering role in the homeostatic maintenance of tissue phospholipid levels of arachidonic acid. 相似文献
18.
Ruijiao Zhang Yuanmin Zhu Liang Ren Pengpeng Zhou Jingrong Hu Longjiang Yu 《Biotechnology letters》2013,35(3):431-438
A new full-length cDNA (PsD6) putatively encoding a ?6-desaturase was cloned from the eicosapentaenoic acid-producing fungus Pythium splendens RBB-5. PsD6 contained an open reading frame of 1380 bp encoding a protein of 459 amino acids. The deduced amino acid sequence showed high similarity to those of other ?6-desaturases. A recombinant vector expressing PsD6 (pPIC3.5K-D6) was constructed and transformed into Pichia pastoris GS115. The heterologous expressed PsD6 in P. pastoris desaturated linoleic acid to γ-linolenic acid but not desaturated α-linolenic acid to stearidonic acid. The results indicated that PsD6 was a fatty acid ?6-desaturase and it had a substrate specificity for linoleic acid. 相似文献
19.
Avutu S. Reddy Michael L. Nuccio Lisa M. Gross Terry L. Thomas 《Plant molecular biology》1993,22(2):293-300
The enzyme 6-desaturase is responsible for the conversion of linoleic acid (18:2) to -linolenic acid (18:3). A cyanobacterial gene encoding 6-desaturase was cloned by expression of a Synechocystis genomic cosmid library in Anabaena, a cyanobacterium lacking 6-desaturase. Expression of the Synechocystis 6-desaturase gene in Anabaena resulted in the accumulation of -linolenic acid (GLA) and octadecatetraenoic acid (18:4). The predicted 359 amino acid sequence of the Synechocystis 6-desaturase shares limited, but significant, sequence similarity with two other reported desaturases. Analysis of three overlapping cosmids revealed a 12-desaturase gene linked to the 6-desaturase gene. Expression of Synechocystis 6-and 12-desaturase in Synechococcus, a cyanobacterium deficient in both desaturases, resulted in the production of linoleic acid and -linolenic acid. 相似文献
20.
Dong-Hoon Kang Periasamy Anbu Won-Ho Kim Byung-Ki Hur 《Biotechnology and Bioprocess Engineering》2008,13(4):483-490
Thraustochytrium aureum ATCC 34304 produces a high level of polyunsaturated fatty acids (PUFAs), which are typically synthesized by strings of reactions
catalyzed by desaturase and elongase enzymes. In this study, the genes related to the biosynthesis of PUFAs were investigated
and targeted to enable optimization of the production of PUFAs. To the best of our knowledge, this is first study to evaluate
the co-expression of genes TaElo, Tad5, and Tad4genes derived from T. aureum. We found that C22 PUFAs such as docosapentaenoic acid (DPA, C22:5n–6) and docosahexaenoic acid (DHA, 22:6n–3) were synthesized
from γ-linolenic acid (GLA, C18:3n–6) and stearidonic acid (SDA, C18:4n–3), respectively, as exogenous substrates via a series of
reactions catalyzed by an Elo-like enzyme and Δ5, Δ4-desaturase enzymes. In addition, the results of this study revealed that
the TaElo gene could synthesize the Δ6-and Δ5-elongation products. Taken together, these results confirmed that the Elo-like enzyme
was involved in multiple reactions leading to the production of PUFAs and that the TaElo, Tad5, and Tad4 genes were capable of functioning together to produce DPA and DHA using GLA and SDA. 相似文献