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1.
Cheawchanlertfa P Cheevadhanarak S Tanticharoen M Maresca B Laoteng K 《Molecular biology reports》2011,38(5):3455-3462
2.
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
3.
Boron enters plant roots as undissociated boric acid (H3BO3). Significant differences in B uptake are frequently observed even when plants are grown under identical conditions. It has
been theorized that these differences reflect species differences in permeability coefficient of H3BO3 across plasma membrane. The permeability coefficient of boric acid however, has not been experimentally determined across
any artificial or plant membrane. In the experiments described here the permeability coefficient of boric acid in liposomes
made of phosphatidylcholine was 4.9 × 10−6 cm sec−1, which is in good agreement with the theoretical value. The permeability coefficient varied from 7 × 10−6 to 9.5 × 10−9 cm sec−1 with changes in sterols (cholesterol), the type of phospholipid head group, the length of the fatty acyl chain, and the pH
of the medium. In this study we also used Arabidopsis thaliana mutants which differ in lipid composition to study the effect of lipid composition on B uptake. The chs1-1 mutant which has lower proportion of sterols shows 30% higher B uptake compared with the wild type, while the act1-1 mutant which has an increased percentage of longer fatty acids, exhibited 35% lower uptake than the wild type. Lipid composition
changes in each of the remaining mutants influenced B uptake to various extents. These data suggest that lipid composition
of the plasma membrane can affect total B uptake.
Received: 15 October 1999/Revised: 11 February 2000 相似文献
4.
Vince Ördög Wendy A. Stirk Péter Bálint Csaba Lovász Otto Pulz Johannes van Staden 《Journal of applied phycology》2013,25(1):233-243
Thirty Chlorella and 30 Scenedesmus strains grown in nitrogen-stressed conditions (70 mg L?1 N) were analyzed for biomass accumulation, lipid productivity, protein, and fatty acid (FA) composition. Scenedesmus strains produced more biomass (4.02?±?0.73 g L?1) after 14 days in culture compared to Chlorella strains (2.57?±?0.12 g L?1). Protein content decreased and lipid content increased from days 8 to 14 with an increase in triacylglycerol (TAG) accumulation in most strains. By day 14, Scenedesmus strains generally had higher lipid productivity (53.5?±?3.7 mg lipid L?1 day?1) than Chlorella strains (35.1?±?2.8 mg lipid L?1 day?1) with the lipids consisting mainly of C16–18 TAGs. Scenedesmus strains generally had a more suitable FA profile with higher amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs) and a smaller polyunsaturated fatty acid (PUFA) component. Chlorella strains had a larger PUFA component and smaller MUFA component. The general trend in the FA composition of Chlorella strains was oleic > palmitic > α-linolenic = linoleic > eicosenoic > heptadecenoic > stearic acid. For Scenedesmus strains, the general trend was oleic > palmitic > linoleic > α-linolenic > stearic > eicosenoic > palmitoleic > heptadecenoic acid. The most promising strains with the highest lipid productivity and most suitable FA profiles were Scenedesmus sp. MACC 401, Scenedesmus soli MACC 721, and Scenedesmus ecornis MACC 714. Although Chlorella sp. MACC 519 had lower lipid productivity, the FA profile was good with a lower PUFA component compared to the other Chlorella strains analyzed and a low linolenic acid concentration. 相似文献
5.
6.
Larsen A Sliskovic I Juric D Pinnock CL Kullman H Segstro E Reinfelds G Eze MO 《Applied microbiology and biotechnology》2005,68(4):548-553
Fatty acids of Azotobacter vinelandii ATCC 12837 were determined at various times during aerobic vegetative growth at 30°C to provide baseline data for studying
the effects of chemical agents on the organism’s survival and fatty acid biosynthesis. Palmitate (16:0) was the highest at
36.7±4.3 mol% (mean±SD) after the first 5 h in fresh culture, decreasing slightly to 33.4±2.6 mol% at 49 h. The other fatty
acids were therefore each normalized as a ratio of 16:0. At 5 h, as a ratio of 16:0, myristate (14:0) was 0.14±0.06, palmitoleate
(16:1cΔ9–10) 0.13±0.06, oleate (18:1cΔ9–10) 0.21±0.12, cis-vaccenate (18:1cΔ11–12) 0.30±0.17 and stearate (18:0) 0.68±0.02. As the growth phase advanced to 49 h, 14:0 and 16:1cΔ9–10 increased, 18:1cΔ9–10 decreased and cis-vaccenate reciprocally increased, whereas 18:0 decreased. These suggest that the saturated fatty acid biosynthesis pathway
yielded 16:0 and 18:0 in the 5-h lag period. By desaturation, 18:0 formed the unsaturated fatty acid (UFA) 18:1cΔ9–10. As the culture aged, the anaerobic UFA biosynthesis pathway formed 16:1cΔ9–10, which was elongated to 18:1cΔ11–12. These fatty acid alterations represent a homeoviscous adaptation, modulating the microbe’s membrane lipid viscosity for
optimal cellular function. 相似文献
7.
Changes in desaturase activity and the fatty acid composition of microsomal membranes from liver tissue of thermally-acclimating rainbow trout 总被引:1,自引:0,他引:1
Arthur F. Hagar Jeffrey R. Hazel 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1985,156(1):35-42
Summary Rainbow trout (Salmo gairdneri) were acclimated to either 5 or 20°C, and then transferred to the opposite temperature, and changes in the fatty acid composition
of liver microsomal membranes and the activities of the hepatic Δ9, Δ6, and Δ5 desaturases were measured at intervals of up
to one month post-transfer. Inital changes (days 0–3) in fatty acid composition were: (1) an increase in the proportion of
saturates and a decrease in the proportion of polyunsaturates during warm acclimation, and (2) a decrease in the proportion
of saturates during cold acclimation. The activity of the Δ6 desaturase approximately doubled immediately following the changes
in temperature, but alterations in Δ9 and Δ5 desaturase activities required at least 3 days to occur. The results indicate
that desaturase enzymes do not play a major role in the initial adaptation of membrane fatty acid composition to changes in
temperature. However, the desaturase enzymes may be involved in the later stages (3–28 days) of the acclimatory process. The
proportion of monoenes was well correlated with Δ9 desaturase activity during both transfers, and appeared to be adjusted
as required to offset changes in the proportion of polyunsaturates.
Supported by National Science Foundation Grant PCM-8301757 to J.R.H. 相似文献
8.
The present study examines the extent to which the fatty acid composition of the membrane lipid can be altered by nutritional means in mutants of Escherichia coli defective in total fatty acid synthesis. These changes are compared to those observed in wild type cells subjected to the same conditions of fatty acid supplementation. Abnormalities in physiological behavior of whole cells and membranes are related to extremes in fatty acid composition that can be produced in the mutant but not the wild type cells. In particular, when the saturated fatty acid of the membrane lipid is reduced below approx. 15% the barrier properties of the membrane toward small molecules such as K+ and a lactose analog decreases abruptly. This change is also reflected in the diminished temperature dependence of passive permeability and of NADH oxidase activity associated with the cytoplasmic membrane. Detailed studies on the properties of specific membrane function in relation to the physical behavior of membrane lipids should be possible with this biological system possessing a relatively simple membrane lipid structure in which the mole percentage of specific lipid components can be systematically varied. 相似文献
9.
Eiji Sakuradani Akinori Ando Jun Ogawa Sakayu Shimizu 《Applied microbiology and biotechnology》2009,84(1):1-10
Studies on the application of functional lipids such as polyunsaturated fatty acids (PUFAs) have proceeded in various fields
regarding health and dietary requirements in a search for novel and rich sources. Filamentous fungus Mortierella alpina 1S-4 produces triacylglycerols rich in arachidonic acid, ones reaching 20 g/L and containing 30–70% arachidonic acid as to
the total fatty acids. Mutants derived from M. alpina 1S-4, defective in Δ5 and Δ6 desaturases, accumulate triacylglycerols rich in unique PUFAs, i.e., dihomo-γ-linolenic acid
and Mead acid, respectively. Furthermore, various mutants derived from M. alpina 1S-4 have led to the production of oils containing n−1, n−3, n−4, n−6, n−7, and n−9 PUFAs. A variety of genes encoding fatty acid desaturases and elongases involved in PUFA biosynthesis in M. alpina 1S-4 has been isolated and characterized. Molecular breeding of M. alpina strains by means of manipulation of these genes facilitates improvement of PUFA productivity and elucidation of the functions
of enzymes involved in PUFA biosynthesis. 相似文献
10.
The effects of different phenolic compound concentrations on the fatty acid composition of Lactobacillus plantarum isolated from traditional home-made olive brines were determined. Increasing amounts of caffeic and ferulic acids induced
a gradual increase in the amounts of myristic, palmitoleic, stearic and 9,10-methylenehexadecanoic (C17Δ, where Δ represents
the cyclopropane group) acid with a concomitant decrease of lactobacillic acid (C19Δ). On the other hand, the addition of tannins induced an increase in the C19Δ level at the expense of vaccenic acid content. The presence of acidic phenols and tannins also affected bacterial growth,
inducing the most obvious effect with tannin at 1 g l−1.
Received: 1 July 1997 / Received revision: 9 September 1997 / Accepted: 15 September 1997 相似文献
11.
Nadia C. S. Mykytczuk Jack T. Trevors Susan M. Twine Garry D. Ferroni Leo G. Leduc 《Archives of microbiology》2010,192(12):1005-1018
Psychrotrophic strains of Acidithiobacillus ferrooxidans have an important role in metal leaching and acid mine drainage (AMD) production in colder mining environments. We investigated
cytoplasmic membrane fluidity and fatty acid alterations in response to low temperatures (5 and 15°C). Significant differences
in membrane fluidity, measured by polarization (P) of 1,6-diphenyl-1,3,5-hexatriene (DPH), were found where the psychrotrophic
strains had a significantly more rigid membrane (P range = 0.41–0.45) and lower transition temperature midpoints (T
m = 2.0°C) and broader transition range than the mesophilic strains (P range = 0.38–0.39; T
m = 2.0–18°C) at cold temperatures. Membrane remodeling was evident in all strains with a common trend of increased unsaturated
fatty acid component in response to lower growth temperatures. In psychrotrophic strains, decreases in 12:0 fatty acids distinguished
the 5°C fatty acid profiles from those of the mesophilic strains that showed decreases in 16:0, 17:0, and cyclo-19:0 fatty
acids. These changes were also correlated with the observed changes in membrane fluidity (R
2 = 63–97%). Psychrotrophic strains employ distinctive modulation of cytoplasmic membrane fluidity with uncommon membrane phase
changes as part of their adaptation to the extreme AMD environment in colder climates. 相似文献
12.
N. P. Mikhailova E. F. Sorokoletova E. N. Durasova K. A. Vyunov O. I. Shapovalov 《Folia microbiologica》1991,36(2):148-152
Composition of sterol fractions of nystatin-resistantCandida maltosa strains was determined. Using UV-spectrometry, TLC and GLC-MS it was demonstrated that resistance to nystatin is connected
with the composition alterations of yeast cell sterols. Block of different stages of ergosterol biosynthesis was revealed
in some mutants,viz. C-24-transmethylation, Δ8→Δ7, 14α-demethylation, C-5(6)-dehydrogenation, reduction of C-14(15) and C-24(28) double bonds. 相似文献
13.
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
14.
Siristova L Luhovy R Sigler K Rezanka T 《Extremophiles : life under extreme conditions》2011,15(3):423-429
Two thermophilic strains belonging to Geobacillus stearothermophilus and Meiothermus ruber, which naturally do not synthesize ω-alicyclic fatty acids (ω-FAs) were cultivated with cyclopropyl, cyclobutyl, cyclopentyl
and cyclohexyl carboxylic acids. Gas chromatography–mass spectrometry analysis of fatty acid methyl and picolinyl esters showed
that both strains are able to synthesize ω-FAs when cultivated with the appropriate precursor. The incorporation of cyclic
acids influenced the whole FA composition as well as membrane fluidity. Membrane fluidity of intact cells was studied by measuring
the fluorescence polarisation of the probe l,6-diphenyl-1,3,5-hexatriene incorporated into membrane lipid bilayers. Cytoplasmic
membrane became more fluid with increasing content of ω-FAs. This is caused by considerable changes in lipid packing within
the membrane induced by the presence of ω-FAs not found in the natural environment of Geobacillus and Meiothermus strains. 相似文献
15.
C. Fuentes-Grünewald E. Garcés E. Alacid N. Sampedro S. Rossi J. Camp 《Journal of industrial microbiology & biotechnology》2012,39(1):207-216
Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions
with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and
temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids.
Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions
(57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly
change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated
fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs,
especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment
of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass,
with high oil content and minimal changes in the fatty acid profile of the strains under consideration. 相似文献
16.
The effect of polyunsaturated fatty acids on photosynthesis and the growth of the marine cyanobacterium Synechococcus sp. PCC 7002 was examined using wild-type and Δ12 fatty acid desaturase mutant strains. Under a light intensity of 250 μmol
m−2 s−1, wild-type cells could grow exponentially in a temperature range of 20–38 °C, but growth was non-exponential below 20 °C
and ceased at 12 °C. The Δ12 desaturase mutant cells lacking polyunsaturated fatty acids had the same growth rate as wild-type
cells in a temperature range of 25–38 °C but grew slowly at 22 °C, and no cell growth took place below 18 °C. Under a very
high-light intensity of 2.5 mmol m−2 s−1, wild-type cells could grow exponentially in a temperature range of 30–38 °C, although the high-light grown cells became
chlorotic because of nitrogen limitation. The temperature sensitive phenotype in the Δ12 desaturase mutant was enhanced in
cells grown under high-light illumination; the mutant cells could grow at 38 °C, but were killed at 30 °C. The decrease of
oxygen evolution and nitrate consumption by whole cells as a function of temperature was similar in both wild type and the
Δ12 desaturase mutant. No differences were observed in either light-induced damage of oxygen evolution or recovery from this
damage. No inactivation of oxygen evolution took place at 22 °C under the normal light intensity of 250 μmol m−2 s−1. These results suggest that growth of the Δ12 desaturase mutant at low temperature is not directly limited by the inactivation
of photosynthesis, and raise new questions about the functions of polyunsaturated membrane lipids on low temperature acclimation
in cyanobacteria.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
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
18.
Cecilia A. Popovich Cecilia Damiani Diana Constenla Patricia I. Leonardi 《Journal of applied phycology》2012,24(1):1-10
Since the fatty acid ester profile of a given biofuel is relatively consistent with the source’s fatty acid profile, the properties
of the biodiesel produced from a particular feedstock exhibit predictable quality. Thus, lipid fractions and the fatty acid
composition of stationary growth-phase cultures of the local strains of the diatoms Skeletonema costatum and Navicula gregaria were analysed to evaluate their suitability as biodiesel feedstock. Total lipid content was 20.83 pg cell−1 in S. costatum and 19.17 pg cell−1 in N. gregaria. Neutral lipids were the main fraction of total lipids in both species, accounting for ca. 65% and 76%, respectively. S. costatum was predominant in saturated fatty acids (SFAs; 43.48 %) and monounsaturated fatty acids (MUFAs; 40.11%), while N. gregaria was predominant in MUFAs (54.85%), followed by SFAs (33.42%). In S. costatum, the main fatty acids in neutral lipid fraction were myristic, palmitic, palmitoleic and oleic acids, while the main ones
in N. gregaria were palmitic and palmitoleic acids. The oils extracted from these species presented linolenic acid contents within biodiesel’s
quality specifications. However, in neutral lipid fraction both species showed eicosapentaenoic acid levels higher than the
required limit. The lipid quality analysed in both species suggests that a biodiesel derived from these oils may present an
acceptable cetane number, but likely poor cold-flow properties. This baseline information is useful for future research tending
to find more suitable conditions in order to improve oil yield. In addition, both estuarine species neither compete with agriculture
for food nor require farmland nor fresh water. 相似文献
19.
20.
Yun-Tao Li Mao-Teng Li Chu-Hua Fu Peng-Peng Zhou Jian-Min Liu Long-Jiang Yu 《Biotechnology letters》2009,31(7):1011-1017
Genes encoding Δ6 desaturase, Δ6 fatty acid elongase, and Δ5 desaturase from the alga, Phaeodactylum tricornutum, were co-expressed in Pichia pastoris to produce arachidonic acid (ARA; 20:4 Δ5, 8, 11, 14) and eicosapentaenoic acid (EPA; 20:5 Δ5, 8, 11, 14, 17). A panel of Pichia clones carrying progressively increasing copies of the heterologous gene expression cassette was created using an in vitro
multimerization approach. ARA and EPA accumulated up to 0.3 and 0.1% of total fatty acids, respectively, in the recombinant
P. pastoris carrying with double copies of these three heterologous genes, as compared to 0.1 and 0.05%, respectively, in the recombinant
P. pastoris with single copy.
Yun-Tao Li and Mao-Teng Li contributed equally to this work. 相似文献