Phospholipid Alterations During Growth of Escherichia coli

As cultures of Escherichia coli progressed from the exponential growth phase to the stationary growth phase, the phospholipid composition of the cell was altered. Unsaturated fatty acids were converted to cyclopropane fatty acids, and phosphatidyl glycerol appears to have been converted to cardiolipin. With dual isotope label experiments, the kinetics of synthesis of cyclopropane fatty acid for each of the phospholipids was examined in vivo. The amount of cyclopropane fatty acid per phospholipid molecule began to increase in phosphatidyl ethanolamine at a cell density below the density at which this increase was observed in phosphatidyl glycerol or cardiolipin. The rate of this increase in phosphatidyl glycerol or in cardiolipin was faster than the rate of increase in phosphatidyl ethanolamine. After a few hours of stationary-phase growth, all the phospholipids were equally rich in cyclopropane fatty acids. It is suggested that the phospholipid alterations observed are a mechanism to protect against phospholipid degradation during stationary phase growth. Cyclopropane fatty acid synthetase activity was assayed in cultures at various stages of growth. Cultures from all growth stages examined had the same specific activity in crude extracts.     

Composition of phospholipids and of phospholipid fatty acids and aldehydes in human red cells

Improved methods for lipid analysis that have been developed recently were employed to reevaluate the phospholipid composition, the fatty acid and fatty aldehyde composition of the total phospholipid, and the fatty acid composition of the individual phospholipids of normal human red cells. Thirty-three fatty acids and five fatty aldehydes were estimated and tentatively identified in the total phospholipid of normal human red cells. Additional minor components were evident. The major individual phospholipids were isolated by silicic acid thin-layer chromatography and quantified. The fatty acid compositions of phosphatidyl ethanolamine, phosphatidyl serine, lecithin, and sphingomyelin were determined. Each of these phospholipids showed a distinctive and characteristic fatty acid pattern.     

Lipids of dystrophic and normal mouse muscle: whole tissue and particulate fractions

Myofibrillar, mitochondrial, and microsomal fractions were prepared from normal and dystrophic mouse limb muscle by differential centrifugation and analyzed for phospholipids and cholesterol. Fatty acids and aldehydes of neutral lipids and of phospholipids from whole muscle and particulate fractions were also determined. Normal microsomes contained more lecithin and less total ethanolamine phospholipids and cardiolipin than mitochondria. The myofibrils had an intermediate phospholipid composition, but their cholesterol-phospholipid ratio was smaller than that of the other two fractions. Except for an increased percentage of phosphatidalethanolamine in the dystrophic mitochondria, only the composition of the dystrophic microsomes differed from normal by containing less lecithin but more total ethanolamine phospholipid, phosphatidalethanolamine, sphingomyelin, and cholesterol. No significant differences were found in the fatty acid composition of neutral lipid extracts from normal and dystrophic preparations, but there was a significant decrease in the percentage of 22:6 in phospholipids from both dystrophic whole muscle and microsomes (-25% and -37%, respectively), whereas the 20:4 content was unaltered. By contrast, the percentages of 18:0 and total fatty aldehyde increased significantly. Phospholipid extracts from all dystrophic samples showed a significant decrease in 16:0 and an increase in 18:1 as compared with the normal.     

Polar head groups manipulation of phospholipids in cultured neuroblastoma cells

The phospholipid polar head groups composition of neuroblastoma cells growing in surface cultures was altered as a result of ethanolamine and N-methyl ethanolamine base analogues addition. After 2 days incubation a significant increase of about 30% of the cellular phospholipids and the cholesterol content was evident. These changes were accompanied by a decrease in the cellular adhesive properties and the total cell number. The fatty acid profiles of the phosphoglycerides were practically identical irrespective of the base supplement.     

Age-associated changes in central nervous system glycerolipid composition and metabolism

In this review, changes in brain lipid composition and metabolism due to aging are outlined. The most striking changes in cerebral cortex and cerebellum lipid composition involve an increase in acidic phospholipid synthesis. The most important changes with respect to fatty acyl composition involve a decreased content in polyunsaturated fatty acids (20:4n-6, 22:4n-6, 22:6n-3) and an increased content in monounsaturated fatty acids (18:1n-9 and 20:1n-9), mainly in ethanolamine and serineglycerophospholipids. Changes in the activity of the enzymes modifying the phospholipid headgroup occur during aging. Serine incorporation into phosphatidylserine through base-exchange reactions and phosphatidylcholine synthesis through phosphatidylethanolamine methylation increases in the aged brain. Phosphatidate phosphohydrolase and phospholipase D activities are also altered in the aged brain thus producing changes in the lipid second messengers diacylglycerol and phosphatidic acid.     

Fatty acids of glycerophosphatides in developing chick embryonic brain and liver

Fatty acid compositions of glycerophosphatides of developing chick embryonic brain and liver were compared. In brain, ethanolamine and serine glycerophosphatides contained 30-40% polyunsaturated fatty acids, lecithin almost none (except for arachidonic). In the liver, these acids were equally distributed in the phospholipid fractions. The principal polyunsaturated fatty acids of the ethanolamine and serine glycerophosphatides in brain, liver, and yolk were 22:6, 20:4, and 18:2, respectively. During embryonic development of brain from the 8th day of incubation to hatching, the fatty acid composition of individual glycerophosphatide fractions remained constant. Because of the relative increase of ethanolamine glycerophosphatides and decrease of lecithin, total glycerophosphatides showed a decrease in 16:0 and an increase in 18:0. Substantial amounts of palmitaldehyde and stearaldehyde were present on the 8th day of incubation in the brain ethanolamine glycerophosphatide fraction. During the 3rd week of incubation, the liver showed a two-fold increase in the relative amount of 18:2 in all glycerophosphatide fractions. A decrease of 16:0 in the lecithin fraction and consequently in total glycerophosphatides was also observed during this period. No significant changes in glycerophosphatide fatty acids were observed in the yolk throughout incubation.     

Changes in fatty acid composition of human brain myelin lipids during maturation

Abstract— The variation with age of the fatty acid composition of the major lipids in human brain myelin was compared with that of cerebral white matter from the same region. The myelin was isolated from the semiovale centre of the cerebrum of 27 subjects neonatal to old aged. The phospholipid, cholesterol and galactolipid concentrations were determined in all the samples, as were the proportions of the major phospholipid classes. The proportions of cholesterol and especially of the galactolipids increased in myelin during the first 6 months, and in cerebral white matter up to 2 years. During this period the individual phospholipids also varied substantially. Serine phosphoglycerides and especially sphingomyelins increased, and choline phosphoglycerides decreased. The fatty acid patterns of ethanolamine phosphoglycerides (EPG) and sphingomyelins underwent the largest changes. The proportions of saturated fatty acids in EPG diminished rapidly, and there was an increase of monoenoic acids. Fatty acids of the linoleic acid series showed a peak between 4 and 12 months, after which time their proportion slowly diminished to old age. The major fatty acid of this series was docosatetraenoic acid, 22:4 (n-6), which constituted more than 25% of total fatty acids at the maximum level. The fatty acid changes were larger in cerebral white matter, but from 2 years of age the EPG fatty acid pattern in myelin was similar to that in white matter. The fatty acid changes in serine and choline phosphoglycerides of myelin with maturation were much less striking than in EPG but of a similar type. In myelin sphingomyelin the proportion of saturated long-chain fatty acids, C₁₆-C₂₂, diminished, while that of monoenoic acids increased and continued to do so up to old age. From 2 years of age the fatty acid patterns in myelin and cerebral white matter were quite similar. Also the fatty acid patterns of cerebrosides and sulphatides in cerebral white matter and myelin were the same except for the first 2 months of life. The same fatty acid changes occurred in cerebrosides and sulphatides as in the sphingomyelins, i.e. increased proportions of unsaturated (monoenoic) acids. The proportions of 24:1 and 24h:1 and of the odd-numbered fatty acids 25:1 and 23h:1 continued to increase to old age. The variations of the individual lipid fatty acid patterns were small except in the youngest age classes, in which the variations were presumably ascribable to the difficulty in determining the gestational age.     

Complex lipids of Rhodomicrobium vannielii

Eight components, seven of which contained phosphorus, were found in the phospholipid fraction of Rhodomicrobium vannielii. The major components were lipoamino acid (o-ornithine ester of phosphatidyl glycerol, 46.5%) and phosphatidyl choline (26.5%). The other six components were phosphatidyl glycerol (9.7%), bisphosphatidic acid (6.7%), phosphatidyl ethanolamine (4.5%), phosphatidic acid (1.8%), lysophosphatidyl glycerol-o-ornithine ester (3.2%), and N,N-ornithine amide of unidentified fatty acid (0.95%). Total phospholipid accounted for 4.2% of cell dry weight. The major fatty acid was vaccenic acid, C_18:1, which accounted for approximately 90% of the total fatty acids of the complex lipid fraction. The other four fatty acids were C_16:0 (6.25%), C_18:0 (3.8%), C_14:0 (0.7%), and C_16:1 (0.35%). The sulfolipid content was 0.01% of the cell dry weight or 0.14 μmoles per g of dried cells, assuming that its fatty acid component is vaccenic acid. No steroids were detected.     

Effect of temperature acclimatization on the fatty acid composition of goldfish intestinal lipids

1. The fatty acid composition of whole goldfish, whole-intestinal mucosa, intestinal mucosal membranes and individual phospholipids extracted from mucosal membranes were measured, fish adapted to different temperatures being used. 2. Alterations of the adaptation temperature did not noticeably affect the fatty acid composition of the whole-fish lipids, but there were marked changes in the fatty acids of lipids extracted from homogenates of goldfish intestinal mucosa. These changes were more pronounced in a membrane fraction prepared from these homogenates. Raising the adaptation temperature by 20 degrees C halved the percentage of C(20:1), C(20:4) and C(22:6) fatty acids and nearly doubled the percentage of C(18:0) and C(20:3) fatty acids recovered. 3. Choline phosphoglycerides constituted about one-half and ethanolamine phosphoglycerides about one-quarter of the total membrane phospholipids. 4. The fatty acids of choline and ethanolamine phosphoglycerides were more susceptible to temperature-dependent changes than were the phosphoglycerides of inositol or serine. 5. The increase in C(18:0) fatty acid that occurred in membranes of warm-adapted fish was greatest for ethanolamine phosphoglycerides, but increases also occurred in other phospholipid fractions and in membrane neutral lipids.     

High plasmalogen and arachidonic acid content of canine myocardial sarcolemma: a fast atom bombardment mass spectroscopic and gas chromatography-mass spectroscopic characterization

Canine myocardial sarcolemma was purified, and its phospholipid constituents were determined by gas chromatography-mass spectrometry, fast atom bombardment mass spectrometry, and conventional techniques. Canine myocardial sarcolemma contained 2.7 mumol of lipid Pi/mg of protein which was comprised predominantly of choline glycerophospholipids (47%), ethanolamine glycerophospholipids (28%), and sphingomyelin (11%). Sarcolemmal phospholipids contained 40% plasmalogen which was quantitatively accounted for by choline (57% of choline glycerophospholipid) and ethanolamine (64% of ethanolamine glycerophospholipid) plasmalogens. Choline plasmalogens contained predominantly the vinyl ether of palmitic aldehyde though ethanolamine plasmalogens were composed predominantly of the vinyl ethers of stearic and oleic aldehydes. The majority of sarcolemmal ethanolamine glycerophospholipids (75%) contained arachidonic acid esterified to the sn-2 carbon. Sphingomyelin was composed predominantly of long-chain saturated fatty acids (stearic and arachidic) as well as substantial amounts (8%) of odd chain length saturated fatty acids. The possible functional role of these unusual phospholipid constituents is discussed.     

Dietary DHA supplementation causes selective changes in phospholipids from different brain regions in both wild type mice and the Tg2576 mouse model of Alzheimer's disease

Alzheimer's disease (AD) is of major concern in ageing populations and we have used the Tg2576 mouse model to understand connections between brain lipids and amyloid pathology. Because dietary docosahexaenoic acid (DHA) has been identified as beneficial, we compared mice fed with a DHA-supplemented diet to those on a nutritionally-sufficient diet.Major phospholipids from cortex, hippocampus and cerebellum were separated and analysed. Each phosphoglyceride had a characteristic fatty acid composition which was similar in cortex and hippocampus but different in the cerebellum. The biggest changes on DHA-supplementation were within ethanolamine phospholipids which, together with phosphatidylserine, had the highest proportions of DHA. Reciprocal alterations in DHA and arachidonate were found. The main diet-induced alterations were found in ethanolamine phospholipids, (and included their ether derivatives), as were the changes observed due to genotype. Tg mice appeared more sensitive to diet with generally lower DHA percentages when on the standard diet and higher relative proportions of DHA when the diet was supplemented. All four major phosphoglycerides analysed showed age-dependent decreases in polyunsaturated fatty acid contents.These data provide, for the first time, a detailed evaluation of phospholipids in different brain areas previously shown to be relevant to behaviour in the Tg2576 mouse model for AD. The lipid changes observed with genotype are consistent with the subtle alterations found in AD patients, especially for the ethanolamine phospholipid molecular species. They also emphasise the contrasting changes in fatty acid content induced by DHA supplementation within individual phospholipid classes.     

Altered lipid composition of adipose tissue in human muscular dystrophy

Lipids of subcutaneous adipose tissue from normal and dystrophic human samples were investigated with particular reference to the fatty acid composition of neutral lipids and phospholipids. The free fatty acid pattern did not show much change. Triglyceride, which together with cholesterol composed most of the neutral lipid fraction, showed significant changes in fatty acid composition by gas-liquid chromatography (GLC). There was a decrease in the total phospholipids. Analysis of the levels of individual phospholipids, however, showed an increase in sphingomyelin and ethanolamine phosphoglyceride contents. Fatty acid composition of the different phospholipid classes analyzed by GLC showed significant changes.     

Sterol carrier protein-2 expression alters phospholipid content and fatty acyl composition in L-cell fibroblasts

The effects sterol carrier protein-2 (SCP-2) expression on L-cell phospholipid levels and fatty acyl composition was assessed using L-cells transfected with the murine cDNA encoding for either the 15 kDa proSCP-2 or 13.2 kDa SCP-2. Expression of these proteins reduced total phospholipid mass (nmol/mg protein) by 24% and reduced the cholesterol to phospholipid ratio 60 and 28%, respectively. In 15 kDa proSCP-2 expressing cells, individual phospholipid class masses, excluding sphingomyelin (CerPCho), were reduced as follows: phosphatidylinositol (PtdIns) and phosphatidylserine (PtdSer) > ethanolamine glycerophospholipid (EtnGpl) > choline glycerophospholipid (ChoGpl). Furthermore, ethanolamine plasmalogen mass was decreased 25%, while choline plasmalogen mass was elevated 30% in 15 kDa proSCP-2 expressing cells. In 13.2 kDa SCP-2 expressing cells, phospholipid class mass was decreased as follows: PtdIns and PtdSer > ChoGpl. These changes in phospholipid mass resulted in altered cellular phospholipid composition. Expression of either protein differentially altered the type of fatty acid esterified onto the phospholipids. These effects included a greater proportion of polyunsaturated fatty acids and a reduction in saturated fatty acids, although 15 kDa proSCP-2 expression had a more robust effect on these parameters than did 13.2 kDa SCP-2 expression. In summary, expression of SCP-2 reduced individual phospholipid class mass, except for CerPCho, and altered the fatty acid composition of each phospholipid class examined.These results clearly demonstrate that SCP-2 expression altered basal phospholipid levels, suggesting that SCP-2 can alter the function of endoplasmic reticulum phospholipid synthetic enzymes.     

Frost-induced phospholipid changes in cold-acclimated and non-acclimated rape leaves

Freezing and thawing of winter rape leaves was found to cause a marked decrease of total phospholipid content in general, and that of phosphatidyl choline in particular. In the highly injured leaves the decrease of phosphatidyl choline was irreversible, and it was accompanied by a marked increase of phosphatidic acid. In the slightly damaged leaves no phosphatidic acid accumulation was detected, irrespective of phosphatidyl choline decrease. Instead of phosphatidic acid, the phosphatidyl glycerol or an unidentified P-containing lipid increased after thawing in leaves hardened to the first (T_k50=?8°C) or to the second (T_k50=?13.5°C) level, respectively. Frost hardening was found to promote phospholipid recovery after freezing and to increase phospholipid content, including that of phosphatidyl choline and phosphatidyl ethanolamine. Possible association of frost hardening with modified phospholipase-D properties is suggested.     

Preferential inhibition of phosphatidyl ethanolamine synthesis in E. coli by alcohols.

Growth of E. coli in the presence of alcohols of chain lengths 1 through 8 results in an increase in the relative abundance of phosphatidyl glycerol. This results primarily from the preferential inhibition of phosphatidyl ethanolamine synthesis. This inhibition appears to be unrelated to membrane fluidity or to changes in fatty acid composition caused by alcohols. Alcohol-induced changes in total fatty acid composition are reflected in all phospholipid classes. Phosphatidyl serine synthetase is proposed as the most likely site for the effects of alcohols on phospholipid synthesis.     

Changes in phospholipid composition during the development of Dictyostelium discoideum

The phospholipid composition of Dictyostelium discoideum cells was determined at various stages of development by two-dimensional, thin-layer chromatography and reaction thin-layer chromatography. Major phospholipids of D. discoideum which were detectable throughout all stages of development were ethanolamine phosphoglyceride and choline phosphoglyceride. Ethanolamine phosphoglyceride and choline phosphoglyceride were found as their plasmalogen forms at 45–58 and 10–24%, respectively. There were no qualitative changes in phospholipid composition during the development, but quantitative changes did occur. The relative content of ethanolamine phosphoglyceride in the total phospholipids gradually decreased from 60% at the vegetative stage to 44% at the 1-day-sorocarp stage. In contrast, choline phosphoglyceride gradually increased from 27% at the vegetative stage to 48% at the preculmination stage, and then gradually decreased to 43% during the culmination. The decrease in ethanolamine phosphoglyceride content during the middle and late development was due mainly to the decreased amount of its plasmalogen form but the increase of choline phosphoglyceride was independent of quantitative changes of its plasmalogen form. Other minor components of phospholipid did not show significant changes in their levels. The causes of these changes in contents of ethanolamine phosphoglyceride and choline phosphoglyceride were examined by label and chase experiments with [³H]ethanolamine and [¹⁴C]choline. It seems that one-third to one-half of the increased amount of choline phosphoglyceride was due to stepwise methylation of ethanolamine phosphoglyceride, and the remaining two-thirds to one-half was caused by de novo synthesis of choline phosphoglyceride from CDP-choline and diglyceride.     

Decreased cytochrome oxidase activity in hepatic mitochondria after chronic ethanol consumption and the possible role of decreased cytochrome aa3 content and changes in phospholipids

In ethanol-fed baboons, hepatic mitochondrial cytochrome oxidase activity and cytochrome aa₃ content were significantly decreased by 58.3 and 50.5%, respectively, compared to their pair-fed controls. However, there was no significant correlation between the two, suggesting that other factors in addition to cytochrome aa₃ may be responsible for the depression in cytochrome oxidase activity. The total phospholipid content of the mitochondrial membranes was significantly decreased (0.24 ± 0.03 μmol of phospholipid phosphorus/mg of protein vs. 0.32 ± 0.04 in controls). This change was accounted for, in part, by the significant decrease in the levels of phosphatidylcholine and cardiolipin. In addition, the fatty acid pattern of the phospholipids was changed. There was a marked increase in the relative amounts of oleic and linoleic acid and a decrease in arachidonic acid. These changes were associated with an increase in the activity of phospholipase A₂. The reactivation rate of phospholipid-depleted cytochrome oxidase by endogenous phospholipids from ethanol-fed baboons was significantly lower than that by phospholipid from pair-fed controls, when measured at an optimal phospholipid to protein ratio. Thus, it appears that alterations in the phospholipid composition of the mitochondrial membranes are responsible, at least in part, for the depression of cytochrome oxidase activity produced by chronic ethanol consumption.     

Lipid Composition in Scrapie-Infected Mouse Brain: Prion Infection Increases the Levels of Dolichyl Phosphate and Ubiquinone

Abstract: The neutral and phospholipid composition of mouse brain infected with scrapie prions was investigated. During the later stages of this disease, the level of dolichol decreased by 30% whereas the level of dolichyl phosphate increased by 30%. In terminally ill mice, there was also a 2.5-fold increase in both total ubiquinone and its reduced form. Furthermore, α-tocopherol was elevated at this stage by 50%. In contrast, no changes were observed in phospholipid amount, in phospholipid composition, and in phosphatidylethanolamine plasmalogen content during the entire disease process. The fatty acid and aldehyde composition of individual phospholipids remained unaltered as well. No modifications could be detected in cholesterol content. Thus, the majority of membrane lipids in scrapie-infected mouse brain are modified in neither quantity nor structure, but specific changes occur to a few polyisoprenoid lipids. This specificity indicates that, although prions accumulate in lysosomes, the infection process is not associated with a general membrane destruction caused by lysosomal enzyme leakage.     

Replacement of acyl and alk-1-enyl groups in Clostridium butyricum phospholipids by exogenous fatty acids.

The effect of exogenous unsaturated fatty acids on the acyl and alk-1-enyl group composition of the phospholipids of Clostridium butyricum has been examined. Unsaturated fatty acids support the growth of this organism in the absence of biotin. When cells were grown at 37 degrees in media containing oleate or linoleate and a Casamino acid mixture containing traces of biotin, the exogenous fatty acids were found mainly in the alk-1-enyl chains of the plasmalogens with less pronounced incorporation into the acyl chains. However, at 25 degrees in this medium, both the acyl and alk-1-enyl chains contained substantial amounts of the 18:1 supplement plus the C19-cyclopropane chains derived from it. Ak-1-enyl chains in all the major phosphatide classes showed a uniformly high substitution by the oleate supplement in cells grown at 37 degrees. The oleate and C19-cyclopropane content of the acyl chains was more variable among the phosphatide classes. At 37 degrees, trans-9-octadecenoic acid (elaidic acid) also supported growth and was incorporated into both acyl and alk-1-enyl chains at a high level. When cells were grown on oleate at 37 degrees in media containing biotin-free Casamino acids, both the acyl and alk-1-enyl chains had a high level of 18:1 plus C19-cyclopropane chains. In the cells grown at 37 degrees with oleate substantial changes were seen in the phospholipid class composition. There was a large decrease in the ethanolamine plus N-methylethanolamine plasmalogens with a corresponding increase in the glycerol acetals of these plasmalogens. The glycerol phosphoglycerides were also significantly lower with the appearance of an unknown, relatively nonpolar phospholipid fraction.     

Composition and fatty acid content of rat ventral prostate phospholipids

The major phospholipids of rat ventral prostate have been separated and examined using thin-layer chromatography, gas chromatography and mass spectrometry. The main phospholipid classes were choline and ethanolamine glycerophospholipids, accounting for 77.9% of total lipid phosphorus. The prostate also contained small amounts of serine glycerophospholipids and sphingomyelin. The relative proportions of fatty acids in the different phospholipid classes were also determined. Arachidonic acid in prostatic phospholipids is contributed primarily by ethanolamine glycerophospholipids. This fraction contained 65-69 mol% plasmalogens, whereas choline and serine glycerophospholipid fractions contained less than 5 mol% plasmalogens. Ethanolamine, choline and serine plasmalogens contained mainly vinyl ethers of palmitic and stearic aldehydes. Ethanolamine plasmalogens also contained the vinyl ether of oleic aldehyde.