Acids In Phosphatidylcholine Research Articles

Acute and chronic effects of temperature on membrane adjustments in the gills of a neotropical catfish.

Structural modifications in the gill membranes maintain homeostasis under the influence of temperature changes. We hypothesized that thermal acclimation would result in significant modification of phospholipid fatty acids, with modulation of sodium pump activity during acute (24 and 48h) and chronic (15days) thermal shifts in the neotropical reophilic catfish Steindachneridion parahybae. Indeed, the time-course experiment showed acute and chronic changes in gill membrane at the lowest temperatures, notably linked to maintenance of membrane fluidity: significant preferential changes in phosphatidylethanolamine, with decrease of saturated fatty acids and increase of C18:1 in all groups kept below 30°C in chronic trial, increase in polyunsaturated fatty acids n6 and C18:1 at 17 and 12°C compared to 24°C, as soon as the temperature was changed (initial time). Additionally, the activity of the sodium pump increased at 12°C, but without apparent connection with the altered lipid environment. The animals maintained at the lowest temperature showed a higher mortality, possibly because of the approach to the minimum critical temperature for this species, and unexpected results of changes in the fatty acid profile, such as decreased docosahexaenoic acid in phosphatidylethanolamine and increased saturated fatty acids in phosphatidylcholine. This set of mechanisms highlights rheostatic adjustments in this species in the face of temperature changes.

Effect of slaughter weight on carcass characteristics, meat quality, and lipidomics profiling in longissimus thoracis of finishing pigs

Slaughter weight greatly affect carcass characteristics and meat quality. Lipids are considered to be critical contributors to meat quality and vary with different physiological conditions. In this study, we investigated the carcass characteristics, meat quality, and lipidomics profiling of longissimus thoracis from finishing pigs with different slaughter weights. Increasing slaughter weight increased average backfat thickness (p < 0.01) and intramuscular fat content (p < 0.05), and decreased shear force (p < 0.01) and cooking loss values (p < 0.01). A total of 592 lipids from 19 lipid classes identified with lipidomics were analyzed. Phosphatidylcholine and phosphatidylethanolamine levels decreased with the increase in slaughter weight (p < 0.01). There were 101 and 76 significantly different lipids (variable importance in projection > 1, p < 0.05) observed in positive and negative ion modes, respectively. Fatty acids in phosphatidylcholine, specifically oleic and linoleic acids, were significantly altered by slaughter weight (p < 0.05). Our findings provide new insights into the effect of slaughter weight on lipid profiles and highlight the comprehensive lipid profile of pork from heavier pigs.

Lipidomic characterization of omega-3 polyunsaturated fatty acids in phosphatidylcholine and phosphatidylethanolamine species of egg yolk lipid derived from hens fed flaxseed oil and marine algal biomass

Membrane phospholipids, including phosphatidylcholine (PC) and phosphatidylethanolamine (PE), consist of distinct fatty acids occupying the sn-1 and sn-2 positions, reflecting the highly regulated nature of lipid biosynthesis. However, little is known about the influence of dietary lipids on the positional nature of fatty acids in tissues, including the enrichment of omega-3 polyunsaturated fatty acid (PUFA) in chicken egg yolk phospholipids. This study was undertaken to characterize the PC and PE species in egg lipids derived from Lohmann hens (n=10/treatment) randomly allocated to either a control (no supplementation), a flaxseed oil (FO) or a marine algal oil (MA) diet. Each of the FO or MA diets supplied three levels of total omega-3 PUFA (0.20, 0.40 and 0.60% of diet) that were provided for 6 weeks. A combination of multiplexed mass spectrometry (MS) experiments are used to determine total, isobaric, and position molecules for PC and PE in egg yolk. The distribution of phospholipids in the yolk was predominantly PC over PE (~72 vs. 23%, respectively) across treatments. The longer chain PUFA existed in the sn-2 position in the PC and PE. Although docosahexaenoic acid (22:6) formed isomers with fatty acids 16:0, 18:0 and 18:1; it was preferentially enriched in the egg in combination with 16:0 with both the FO and MA-fed groups in both lipid pools. All 22:6-containing isomers were enriched by ~2-fold more (P < 0.0001) with MA than FO, however, all isomers exhibited a plateau with the FO-fed group. In addition, the MS analyses of PCs revealed several isobaric species containing eicosapentaenoic acid (EPA, 20:5), however, in the PE, EPA formed only one isomer (i.e. in combination with 16:0). These results may assist to elucidate potential aspects regulating the limited enrichment of omega-3 PUFA, particularly EPA and docosahexaenoic acid (22:6) in chicken eggs.

Rapid screening of very long-chain fatty acids from microorganisms

The analysis of triacylglycerols and phospholipids - phosphatidylcholines allowed the use of shotgun lipidomics to identify very long-chain fatty acids and very long-chain polyunsaturated fatty acids in microalgae. These fatty acids were determined in triacylglycerols by positive electrospray ionization of neutral loss scans of different fatty acids, e.g. 24:0, 24:1ω9, 24:6ω3, 26:0, 26:1ω9, 28:0, 28:1ω9, 28:2ω6, and 28:8ω3. Likewise, very long-chain fatty acids in phosphatidylcholines were identified by negative electrospray ionization mass spectrometry in the selected ion-monitoring of the two most important ions (R1COO− and R2COO−). The limit of detection was determined at 10 nmol/L (∼11 pg/μL) in triacylglycerols and 8.6 nmoles/L (∼8 pg/μL) in phosphatidylcholines. The use of liquid chromatography–mass spectrometry is suitable for very long-chain polyunsaturated fatty acids with up to 8 double bonds due to the time of analysis as well as for reasons of lower thermal stability of polyunsaturated fatty acids towards saturated fatty acids, but gas chromatography–mass spectrometry is better suited for the analysis of saturated very long-chain fatty acids.

FADS2 inhibition in essential fatty acid deficiency induces hepatic lipid accumulation via impairment of very low-density lipoprotein (VLDL) secretion

Fatty acid desaturase 2 (FADS2) is responsible for the first desaturation reaction in the synthesis of highly unsaturated fatty acids (HUFAs), such as arachidonic acid (20:4n-6) and eicosapentaenoic acid (20:5n-3), and is involved in Mead acid (20:3n-9) production during essential fatty acid deficiency (EFAD). In this study, an obvious hepatic lipid accumulation was observed in EFAD mice treated with a FADS2 inhibitor. FADS2 inhibition in the EFAD state reduced secretion of very low-density lipoprotein (VLDL) and markedly diminished Mead acid in phosphatidylcholine (PC) in the liver and plasma. As the results, the amount of C20 HUFAs in hepatic and plasma PC dramatically reduced in the EFAD mice treated with a FADS2 inhibitor, whereas the decrease of C20 HUFA levels of PC in EFAD mice was not observed because of the increased Mead acid in PC. These results supposed that Mead acid in PC is important as a component of VLDL. It is possible that Mead acid plays the role of a substitute of HUFAs in VLDL secretion during EFAD.

Changes of fatty acids in phosphatidylcholine on sperm membrane during Macrobrachium rosenbergii sperm transit through spermatic duct and lipid analysis in spermatic vesicles

Sperm maturation taking place in male accessory tracts is a complex series of biomolecular dynamics of both lipids and proteins on sperm plasma membrane. In this study, we compared fatty acid (FA) compositions on a single banded phophatidylcholine (PC) in Macrobrachium rosenbergii sperm collected from testis (Tsp) and vas deferens (Vsp) to give an insight of membrane lipid dynamic during sperm maturation. Saturated (SAT, predominantly C16:0) and monounsaturated fatty acids (MUFA, predominantly C18:1, n9) were apparently higher in Vsp whereas the polyunsaturated fatty acids (PUFA, mainly C20:5, n3 and C22:6, n3) were evidently lower. Higher level of PUFA in the Vsp was also supported by merocyanine staining followed by flow cytometric analysis. Imaging mass spectroscopy (IMS) gave both comparative and quantitative data of the paired FA within an intact PC molecule while it also provided FA distribution within the PC band. The levels of lipids, particularly cholesterol (CHO) and sphingomyelin (SM), as well as PUFA and other FA species in the spermatic vesicles (SV) were found to be opposite to those of Vsp. We thus believe that an alteration of lipid compositions in sperm membrane is partly modulated via SV transport in vas deferens, which is considerable a part of sperm maturation process in M. rosenbergii, similar to that reported for mammalian epididymal sperm maturation. Statement of relevanceThis work will provide an insight of lipid dynamics on sperm plasma membrane which relates to a part of sperm maturation process. Nutritional management with the known fatty acid compositions of mature sperm would help to improve sperm quality for practical aquaculture.

Profiling of polar lipids in marine oleaginous diatom Fistulifera solaris JPCC DA0580: prediction of the potential mechanism for eicosapentaenoic acid-incorporation into triacylglycerol.

The marine oleaginous diatom Fistulifera solaris JPCC DA0580 is a candidate for biodiesel production because of its high lipid productivity. However, the substantial eicosapentaenoic acid (EPA) content in this strain would affect the biodiesel quality. On the other hand, EPA is also known as the essential health supplement for humans. EPAs are mainly incorporated into glycerolipids in the microalgal cell instead of the presence as free fatty acids. Therefore, the understanding of the EPA biosynthesis including the incorporation of the EPA into glycerolipids especially triacylglycerol (TAG) is fundamental for regulating EPA content for different purposes. In this study, in order to identify the biosynthesis pathway for the EPA-containing TAG species, a lipidomic characterization of the EPA-enriched polar lipids was performed by using direct infusion electrospray ionization (ESI)-Q-TRAP-MS and MS/MS analyses. The determination of the fatty acid positional distribution showed that the sn-2 position of all the chloroplast lipids and part of phosphatidylcholine (PC) species was occupied by C16 fatty acids. This result suggested the critical role of the chloroplast on the lipid synthesis in F. solaris. Furthermore, the exclusive presence of C18 fatty acids in PC highly indicated the biosynthesis of EPA on PC. Finally, the PC-based acyl-editing and head group exchange processes were proposed to be essential for the incorporation of EPA into TAG and chloroplast lipids.

Very-long-chain polyunsaturated fatty acids accumulate in phosphatidylcholine of fibroblasts from patients with Zellweger syndrome and acyl-CoA oxidase1 deficiency

Peroxisomes are subcellular organelles that function in multiple anabolic and catabolic processes, including β-oxidation of very-long-chain fatty acids (VLCFA) and biosynthesis of ether phospholipids. Peroxisomal disorders caused by defects in peroxisome biogenesis or peroxisomal β-oxidation manifest as severe neural disorders of the central nervous system. Abnormal peroxisomal metabolism is thought to be responsible for the clinical symptoms of these diseases, but their molecular pathogenesis remains to be elucidated. We performed lipidomic analysis to identify aberrant metabolites in fibroblasts from patients with Zellweger syndrome (ZS), acyl-CoA oxidase1 (AOx) deficiency, D-bifunctional protein (D-BP) and X-linked adrenoleukodystrophy (X-ALD), as well as in peroxisome-deficient Chinese hamster ovary cell mutants. In cells deficient in peroxisomal biogenesis, plasmenylethanolamine was remarkably reduced and phosphatidylethanolamine was increased. Marked accumulation of very-long-chain saturated fatty acid and monounsaturated fatty acids in phosphatidylcholine was observed in all mutant cells. Very-long-chain polyunsaturated fatty acid (VLC-PUFA) levels were significantly elevated, whilst phospholipids containing docosahexaenoic acid (DHA, C22:6n-3) were reduced in fibroblasts from patients with ZS, AOx deficiency, and D-BP deficiency, but not in fibroblasts from an X-ALD patient. Because patients with AOx deficiency suffer from more severe symptoms than those with X-ALD, accumulation of VLC-PUFA and/or reduction of DHA may be associated with the severity of peroxisomal diseases.

Composition of meat and offal from weaned and fattened rabbits and results of stereospecific analysis of triacylglycerols and phosphatidylcholines

Rabbit meat has excellent nutritive properties. The purpose of this study was to characterize rabbit meat and offal; in particular, the lipid fraction was studied in order to evaluate total and positional fatty acid (FA) compositions of triacylglycerol (TAG) and phosphatidylcholine (PC) fractions. Eight samples of weaned and eight of fattened rabbits were considered. Fattened rabbit meat contained slightly higher protein percentage content (P < 0.05) in comparison to weaned (20.1% versus 18.0%). Calcium content was higher in meat than in offal, unlike sodium, iron, zinc, manganese and copper. The cholesterol content in offal was much higher than in meat. FA profiles of total lipid showed a high percentage of unsaturated fatty acids and an n-6/n-3 ratio of 10.3 for fattened rabbit meat. Stereospecific analysis of TAG and PC was carried out on an eight-sample pool of each meat and offal from weaned and fattened rabbits. In all samples the sn-2-position was prevalently esterified with oleic and linoleic acids in TAG, with polyunsaturated fatty acids in PC. Lipids from rabbit meat presented higher content of monounsaturated FA and lower n-6/n-3 ratio in comparison to offal, which was characterized by higher cholesterol and mineral levels.

Conserved valproic-acid-induced lipid droplet formation in Dictyostelium and human hepatocytes identifies structurally active compounds

SUMMARYLipid droplet formation and subsequent steatosis (the abnormal retention of lipids within a cell) has been reported to contribute to hepatotoxicity and is an adverse effect of many pharmacological agents including the antiepileptic drug valproic acid (VPA). In this study, we have developed a simple model system (Dictyostelium discoideum) to investigate the effects of VPA and related compounds in lipid droplet formation. In mammalian hepatocytes, VPA increases lipid droplet accumulation over a 24-hour period, giving rise to liver cell damage, and we show a similar effect in Dictyostelium following 30 minutes of VPA treatment. Using 3H-labelled polyunsaturated (arachidonic) or saturated (palmitic) fatty acids, we shown that VPA treatment of Dictyostelium gives rise to an increased accumulation of both types of fatty acids in phosphatidylcholine, phosphatidylethanolamine and non-polar lipids in this time period, with a similar trend observed in human hepatocytes (Huh7 cells) labelled with [3H]arachidonic acid. In addition, pharmacological inhibition of β-oxidation in Dictyostelium phenocopies fatty acid accumulation, in agreement with data reported in mammalian systems. Using Dictyostelium, we then screened a range of VPA-related compounds to identify those with high and low lipid-accumulation potential, and validated these activities for effects on lipid droplet formation by using human hepatocytes. Structure-activity relationships for these VPA-related compounds suggest that lipid accumulation is independent of VPA-catalysed teratogenicity and inositol depletion. These results suggest that Dictyostelium could provide both a novel model system for the analysis of lipid droplet formation in human hepatocytes and a rapid method for identifying VPA-related compounds that show liver toxicology.

PHOSPHOLIPIDS FROM PUMPKIN (&lt;i&gt;Cucurbita moschata&lt;/i&gt; (Duch.) Poir) SEED KERNEL OIL AND THEIR FATTY ACID COMPOSITION

The phospholipids (PL) of pumpkin (Cucurbita moschata (Duch) Poir) seed kernel and their fatty acid composition were investigated. The crude oil was obtained by maceration with isopropanol followed by steps of extraction yielded polar lipids. The quantitative determination of PLs content of the dried pumpkin seed kernel and their polar lipids were calculated based on the elemental phosphorus (P) contents which was determined by means of spectrophotometric methods. PL classes were separated from polar lipids via column chromatography. The fatty acid composition of individual PL was identified by gas chromatography-mass spectrometry (GC-MS). The total of PL in the pumpkin seed kernels was 1.27% which consisted of phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidyletanolamine (PE). The predominant fatty acids of PL were oleic and palmitic acid in PC and PE while PS's fatty acid were dominantly consisted of oleic acid and linoleic acid.

Distinct hepatic lipid profile of hypertriglyceridemic mice determined by easy ambient sonic-spray ionization mass spectrometry

Easy ambient sonic-spray ionization mass spectrometry (EASI-MS) was used to interrogate the hepatic lipid profiles of hypertriglyceridemic and control normotriglyceridemic mice. The analyses of ex vivo complex lipid mixtures were made directly with EASI-MS without accompanying separation steps. Intense ions for phosphatidylcholines and triacylglycerols were observed in the positive ion mode whereas the spectra in the negative ion mode provided profiles of phosphatidylethanolamines and phosphatidylinositol. EASI-MS was coupled to high-performance thin-layer chromatography for analysis of free fatty acids. Fourier transform-ion cyclotron resonance-mass spectrometry was also employed to confirm the identity of the detected lipids. We demonstrated higher incorporation of oleic acid in phosphatidylcholine and triacylglycerol composition, higher relative abundance of arachidonic acid containing phosphatidylinositol, and overall distinct free fatty acid profile in the livers of genetic hypertriglyceridemic mice. We propose that these alterations in liver lipid composition are related to the higher tissue and body metabolic rates described in these hypertriglyceridemic mice.

Modulation of peritoneal macrophage activity by the saturation state of the fatty acid moiety of phosphatidylcholine

To determine the effects of saturated and unsaturated fatty acids in phosphatidylcholine (PC) on macrophage activity, peritoneal lavage cells were cultured in the presence of phosphatidylcholine rich in saturated or unsaturated fatty acids (sat PC and unsat PC, respectively), both used at concentrations of 32 and 64 microM. The treatment of peritoneal macrophages with 64 microM unsat PC increased the production of hydrogen peroxide by 48.3% compared to control (148.3 +/- 16.3 vs 100.0 +/- 1.8%, N = 15), and both doses of unsat PC increased adhesion capacity by nearly 50%. Moreover, 64 microM unsat PC decreased neutral red uptake by lysosomes by 32.5% compared to the untreated group (67.5 +/- 6.8 vs 100.0 +/- 5.5%, N = 15), while both 32 and 64 microM unsat PC decreased the production of lipopolysaccharide-elicited nitric oxide by 30.4% (13.5 +/- 2.6 vs 19.4 +/- 2.5 microM) and 46.4% (10.4 +/- 3.1 vs 19.4 +/- 2.5 microM), respectively. Unsat PC did not affect anion production in non-stimulated cells or phagocytosis of unopsonized zymosan particles. A different result pattern was obtained for macrophages treated with sat PC. Phorbol 12-miristate 13-acetate-elicited superoxide production and neutral red uptake were decreased by nearly 25% by 32 and 64 microM sat PC, respectively. Sat PC did not affect nitric oxide or hydrogen peroxide production, adhesion capacity or zymosan phagocytosis. Thus, PC modifies macrophage activity, but this effect depends on cell activation state, fatty acid saturation and esterification to PC molecule and PC concentration. Taken together, these results indicate that the fatty acid moiety of PC modulates macrophage activity and, consequently, is likely to affect immune system regulation in vivo.

Altered Lipid Parameters in Hepatic Subcellular Membrane Fractions Induced by Fumonisin B1

Alteration of lipid constituents of cellular membranes has been proposed as a possible mechanism for cancer promotion by fumonisin B(1 )(FB(1)). To further investigate this hypothesis a dietary dosage which initiates and promotes liver cancer (250 mg FB(1)/kg) was fed to male Fischer rats for 21 days and the lipid composition of plasma, microsomal, mitochondrial and nuclear subcellular fractions determined. The effect of FB(1) on the cholesterol, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), as well as sphingomyelin (SM) and the phospholipids-associated fatty acid (FA) profiles, were unique for each subcellular membrane fraction. PE was significantly increased in the microsomal, mitochondrial and plasma membrane fractions, whereas cholesterol was increased in both the microsomal and nuclear fraction. In addition SM was decreased and increased in the mitochondrial and nuclear fractions, respectively. The decreased PC/PE and polyunsaturated/saturated (P/S) FA ratio in the different membrane fractions suggest a more rigid membrane structure. The decreased levels in polyunsaturated fatty acids in PC together with a pronounced increase in C18:1omega9 and C18:2omega6 were indicative of an impaired delta-6 desaturase. The increased omega6/omega3 ratio and decreased C20:4omega6 PC/PE ratio due to an increase in C20:4omega6 in PE relatively to PC in the different subcellular fractions suggests a shift towards prostanoid synthesis of the E2 series. Changes in the PE and C20:4omega6 parameters in the plasma membrane could alter key growth regulatory and/or other cell receptors in lipid rafts known to be altered by FB(1). An interactive role between C20:4omega6 and ceramide in the mitochondria, is suggested to regulate the balance between proliferation and apoptosis in altered initiated hepatocytes resulting in their selective outgrowth during cancer promotion effected by FB(1).

Pulmonary surfactant in patients with Pneumocystis pneumonia and acquired immunodeficiency syndrome

Pneumocystis pneumonia (PCP) is a severe infection of the immunocompromised host, resulting in diffuse alveolar damage and life-threatening respiratory failure. We analyzed pulmonary surfactant composition and function in bronchoalveolar lavage fluid (BALF) from ventilated and spontaneously breathing HIV-positive patients with PCP. Prospective clinical trial. University hospital intensive care unit. Thirty-four spontaneously breathing (SB-PCP) and 20 ventilated HIV-positive patients with PCP (V-PCP), ten patients with acute respiratory distress syndrome (ARDS), 11 spontaneously breathing patients with bacterial pneumonia (PNEU), and 22 healthy volunteers. None. Total phospholipid in BALF did not differ between any category vs. controls, whereas total protein increased approximately 14-fold in V-PCP and five-fold in SB-PCP compared with controls (p < .001). The relative content of large surfactant aggregates (LA) was reduced in SB-PCP and V-PCP compared with controls (p < .05). The phospholipid and fatty acid profiles showed a significant reduction in the relative content of phosphatidylcholine (PC), phosphatidylglycerol, and palmitic acid in PC in all patient categories compared with controls, with more in V-PCP (p < .001) compared with SB-PCP (p < .05). The neutral lipid-to-phospholipid ratio in LA was three-fold elevated in V-PCP (p < .01 compared with control) but not in SB-PCP. Analysis of neutral lipid classes showed a significant increase in the relative content of triglycerides and a reduction in free fatty acids in V-PCP compared with controls. BALF surfactant protein (SP)-A and SP-D significantly increased in V-PCP and SB-PCP, but not in ARDS and PNEU, compared with controls (p < .05). SP-B and SP-C content in LA remained unchanged in PCP compared with controls but decreased significantly in ARDS and PNEU. The minimum surface tension of LA was impaired (p < .001) in V-PCP more than in SB-PCP and was strongly correlated with the reduction in palmitic acid levels in PC LA (r = -.81). Reductions in phosphatidylglycerol strongly correlated with decreased Pao2/Fio2 values (r = .72). We conclude that severe alterations in surfactant function and composition occur in patients with PCP and are even more pronounced in ventilated patients than in nonventilated patients. Surfactant lipid changes in PCP, but not surfactant protein profiles, closely resemble those found in ARDS.

Conjugated fatty acids accumulate to high levels in phospholipids of metabolically engineered soybean and Arabidopsis seeds

Expression of Δ 12-oleic acid desaturase-related fatty acid conjugases from Calendula officinalis, Momordica charantia, and Vernicia fordii in seeds of soybean ( Glycine max) or an Arabidopsis thaliana fad3/fae1 mutant was accompanied by the accumulation of the conjugated fatty acids calendic acid or α-eleostearic acid to amounts as high as 20% of the total fatty acids. Conjugated fatty acids, which are synthesized from phosphatidylcholine (PC)-linked substrates, accumulated in PC and phosphatidylethanolamine, and relative amounts of these fatty acids were higher in PC than in triacylglycerol (TAG) in the transgenic seeds. The highest relative amounts of conjugated fatty acids were detected in PC from seeds of soybean and A. thaliana that expressed the C. officinalis and M. charantia conjugases, where they accounted for nearly 25% of the fatty acids of this lipid class. In these seeds, >85% of the conjugated fatty acids in PC were detected in the sn-2 position, and these fatty acids were also enriched in the sn-2 position of TAG. In marked contrast to the transgenic seeds, conjugated fatty acids composed <1.5% of the fatty acids in PC from seeds of five unrelated species that naturally synthesize a variety of conjugated fatty acid isomers, including seeds that accumulate conjugated fatty acids to >80% of the total fatty acids. These results suggest that soybean and A. thaliana seeds are deficient in their metabolic capacity to selectively catalyze the flux of conjugated fatty acids from their site of synthesis on PC to storage in TAG.

Co-expression of the borage Δ6 desaturase and the Arabidopsis Δ15 desaturase results in high accumulation of stearidonic acid in the seeds of transgenic soybean

Two relatively rare fatty acids, gamma-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, alpha-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 Delta(6) desaturase and an Arabidopsis Delta(15) desaturase were pyramided by either sexual crossing of transgenic events, re-transformation of a Delta(6) desaturase event with the Delta(15) desaturase or co-transformation of both desaturases. Expression of both desaturases in this study was under the control of the seed-specific soybean beta-conglycinin promoter. Soybean events that carried only the Delta(15 )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.

FAD2-silencing has pleiotropic effect on polar lipids of leaves and varied effect in different organs of transgenic tobacco

A microsomal ω-6 fatty acid desaturase gene ( FAD2) of tobacco ( Nicotiana tabaccum) was cloned by PCR-based method and a partial coding sequence of the putative FAD2 gene was used to create intron-containing construct expressing hairpin RNA for silencing endogenous FAD2 gene. In addition to a marked increase of oleic acid in phosphatidylcholine and phosphatidylethanolamine, the main lipid components of the extrachloroplastic membranes of plant cells, the silencing of FAD2 resulted in pleiotropic effect on polar lipids of leaves, i.e., a significant increase of oleic acid levels in sulfoquinovosyldiacylglycerol, phosphatidylglycerol, digalactosyldiacylglycerol and monogalactosyldiacylglycerol, located predominantly in the chloroplast, and a significant reduction of palmitic acid levels in some individual polar lipids. The significant increase of oleic acid only found in lipids of leaves and seeds of transgenic lines proved the diversity of the silencing effect in different organs. The possible mechanisms involved in the control of lipid unsaturation level in different organs of transgenic tobacco were discussed.

Effect of cadmium on lipid composition of Aureobasidium pullulans grown with added extracellular polysaccharides

Effect of cadmium on the growth and lipid composition in three Aureobasidium pullulans strains grown in the presence and absence of extracellular polysaccharides was studied. Strains tolerated up to 1 mM Cd 2+ in medium, but addition of either pectin or pullulan to medium increased tolerance to up to 2 mM Cd 2+ . While cadmium enhanced lipid accumulation notably only in strains of CCY 27-1-98 and CCY 27-1-111, strain CCY 27-1-115 displayed considerably high levels of sterols. Cadmium increased fatty acid unsaturation rapidly in phosphatidylethanolamine in all strains, owing to elevated levels of linoleic acid in this lipid fraction. On the other hand, Cd 2+ ions significantly lowered conversion of oleic acid to linoleic acid in phosphatidylcholine only in the strain CCY 27-1-115. Nevertheless, addition of either pullulan or pectin amplified the ratio of C18:C16 fatty acids and the degree of fatty acid unsaturation in all membrane lipids as a result of induced biotransformation of stearate to oleate and linoleate. It was concluded that more saturated membranes with preferred C18 fatty acyl chains and high sterol amounts in the strain CCY 27-1-115 might be connected with its lower capacity to form pullulan as a protective metabolite against heavy metals compared with the other two strains.

Composition of plasma fatty acids and non-cholesterol sterols in anorexia nervosa.

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. The pattern of plasma fatty acids influences the levels of plasma lipids and lipoproteins. The concentration of plasma lathosterol is a surrogate marker of cholesterol synthesis de novo, concentrations of campesterol and beta-sitosterol reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationship to plasma lipids, lipoproteins, cholesterol precursors and plant sterols. We examined 16 women with anorexia nervosa and 25 healthy ones. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol. Moreover, a decreased content of n-6 polyunsaturated fatty acids was found in all lipid classes. These changes were compensated by an increased content of monounsaturated fatty acids in cholesteryl esters, saturated fatty acids in triglycerides and both monounsaturated and saturated fatty acids in phosphatidylcholine. The most consistent finding in the fatty acid pattern concerned a decreased content of linoleic acid and a raised content of palmitoleic acid in all lipid classes. The changes of plasma lipids and lipoproteins in anorexia nervosa are the result of complex mechanisms including decreased catabolism of triglyceride-rich lipoproteins, normal rate of cholesterol synthesis and increased resorption of exogenous cholesterol.