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1.
The product of the ozonolysis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in ethanol-containing solvent was analyzed by chemiluminescence detection-HPLC with on-line electrospray
MS, and characterized on the basis of NMR spectroscopy and MS in high-resolution fast atom bombardment mode. The reaction
yielded a large amount of a novel ethoxyhydroperoxide compound [1-palmitoyl-2-(9-ethoxy-9-hydroperoxynonanoyl)-sn-glycero-3-phosphocholine]. In addition to a structural analysis, we speculate on the reaction pathway and discuss the possibility
of ethoxyhydroperoxide as a potentially reactive ozonized lipid in food and biological materials. 相似文献
2.
The differences in distribution of geometric isomers of unsaturated PC hydroperoxides generated by free radical oxidation
were compared, as corresponding hydroxy analogs, in heterogeneous liposomes and in a homogeneous methanol solution by using
HPLC with UV detection due to the presence of conjugated dienes. Identification of fractionated peak components was carried
out by GC-MS. When the oxidation of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphocholine, PC(16∶0/18∶2), was initiated in liposomes by a hydrophilic azo radical initiator, and in a methanol
solution by a hydrophobic azo radical initiator, there was no significant difference in the relative percentages of 1-palmitoyl-2-(9-hydroxy-trans-10,trans-12-octadecadienoyl)-sn-glycero-3-phosphocholine (9-t,t-OH PC) and 1-palmitoyl-2-(13-hydroxy-trans-9,trans-11-octadecadienoyl)-sn-glycero-3-phosphocholine (13-t,t-OH PC) between the PC oxidized in liposomes and in the methanol solution. For the oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, PC(16∶0/20∶4), the relative percentage of 1-palmitoyl-2-(5-hydroxy-trans-6,cis-8,11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (5-OH PC) was significantly higher (P<0.01) than that of 1-palmitoyl-2-(15-hydroxy-cis-5,8,11,trans-13-eicosatetraenoyl)-sn-glycero-3-phosphocholine (15-OH PC) in liposomes. For the homogeneous methanol solution of PC(16∶0/20∶4), the relative percentage
of 5-OH PC was close to that of 15-OH PC. For the PC(16∶0/20∶4) oxidized in bulk with added pentamethylchromanol, the individual
amount of 15-OH PC, 1-palmitoyl-2-(11-hydroxy-cis-5,8trans-12,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (11-OH PC), 1-palmitoyl-2-(12-hydroxy-cis-5,8,trans-10,cis-14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (12-OH PC), 1-palmitoyl-2-(8-hydroxy-cis-5,trans-9,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (8-OH PC), 1-palmitoyl-2-(9-hydroxy-cis-5,trans-7,cis-11,14-eicosatetraenoyl)-sn-glycero-3-phosphocholine (9-OH PC), and 5-OH PC were close to each other compared to the corresponding values in liposomes
and in methanol solution. The results obtained by gel permeation chromatography of the PC liposomes containing hydrophilic
2,2′-azobis-2-amidinopropane) dihydrochloride (AAPH) suggest that the AAPH added to the liposomes of PC(16∶0/20∶4) was partitioned
into the water phase and out of the hydrophobic region of the fatty acyl moieties of the PC. These results confirm that the
distance that exists in the bis-allylic carbons of the unsaturated fatty acyl moieties of PC from the interface between the
hydrophilic region of PC and the water phases played an important role in influencing hydrogen abstraction to form a symmetrical
distribution of hydroperoxide isomers in both the heterogeneous liposomes and the homogeneous methanol solution. 相似文献
3.
Pravin Kumar Nathalie Schilderink Vinod Subramaniam Martina Huber 《Israel journal of chemistry》2017,57(7-8):762-770
Human α-synuclein, a protein relevant in the brain with so-far unknown function, plays an important role in Parkinson's disease. The phosphorylation state of αS was related to the disease, prompting interest in this process. The presumed physiological function and the disease action of αS involves membrane interaction. Here, we study the effect of phosphorylation at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding. Local binding is detected by spin-label continuous-wave electron paramagnetic resonance. For S87A/D, six positions (27, 56, 63, 69, 76, and 90) are probed; and for S129A/D, three (27, 56, and 69). Binding to large unilamellar vesicles of 100 nm diameter of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in a 1 : 1 composition is not affected by the phosphorylation state of S129. For phosphorylation at S87, local unbinding of αS from the membrane is observed. We speculate that modulating the local membrane affinity by phosphorylation could tune the way αS interacts with different membranes; for example, tuning its membrane fusion activity. 相似文献
4.
It is likely that Criegee ozonides are formed in small amounts in the lungs of animals breathing ozone-containing air. This
makes these compounds potential candidates to act as secondary toxins which relay the toxic effects of ozone deeper into lung
tissue than ozone itself could penetrate. Therefore, we have determined the yields of Criegee ozonides from unsaturated lipids
in liposomal systems as a model of the types of yields of Criegee ozonides that might be expected both in the lung lining
fluid layer and in biological membranes. Ozonation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes produced bothcis- andtrans-Criegee ozonides. These ozonides have been isolated by solid phase extraction and high-performance liquid chromatography
of the ozonized lipid, and the products have been identified by two-dimensional1H nuclear magnetic resonance. The combined yield of thecis- andtrans-Criegee ozonides is 10.7±2.8% (avg. ±SD, n=7) with small unilamellar liposomes and 10.6±2.7% (n=3) with large multilamellar
liposomes. We had previously reported (Chem. Res. Toxicol. 5 505–511, 1992) that ozonation of methyl oleate in sodium dodecylsulfate micelles also produces an 11% yield of the Criegee
ozonides. Thus, ozonation in a variety of models gives about 11% of the Criegee ozonide, suggesting that these products also
would be formed in small but significant amounts in the lungs of animals breathing polluted air. Further research on the pharmacokinetics
and possible toxicity of the Criegee ozonides of fatty acids is suggested. 相似文献
5.
A comparative approach has been used to investigate the molecular species composition of phosphatidylcholine (PC) and its
age variation throughout several developmental stages of chick and duck embryo brains. The brain PC consist of 15 major molecular
species which do not undergo appreciable variation in their relative abundance either during embryonic development or between
equivalent stages of maturation in the 2 avian species. In fact, a highly invariable molecular architecture of PC is shown
in the developing organ. Molecular species containing saturated or monounsaturated fatty acids were dominant in all stages
of development of the avian embryo brain. Among these molecular species, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine accounted for 75–80% of the total PC. 相似文献
6.
Kauffmann I.; Schmidt-Dannert C. 《Protein engineering, design & selection : PEDS》2001,14(11):919-928
The thermoalkalophilic lipase from Bacillus thermocatenulatusBTL2 exhibits a low phospholipase activity (lecithin/tributyrinratio 0.03). A single round of random mutagenesis of the BTL2gene followed by screening of 6000 transformants on egg-yolkplates identified three variants with 1012-fold increasedphospholipase activities, corresponding to lecithin/tributyrinratios of 0.160.36. All variants were specific for thesn-1 acyl ester bond of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine.Mutations occurred predominantly in the N-terminal part of BTL2with regions surrounding the predicted helix 相似文献
7.
The time course of hydrolysis of a mixed phospholipid substrate containing bovine liver 1,2-diacyl-sn-glycero-3-phosphocholine (PC) and 1,2-diacyl-sn-glycero-3-phosphoethanolamine (PE) catalyzed byCrotalus adamanteus phospholipase A2 was measured before and after peroxidation of the lipid substrate. The rate of hydrolysis was increased after peroxidation
by an iron/adenosine diphosphate (ADP) system; the presence of iron/ADP in the assay had a minimal inhibitory effect. The
rate of lipid hydrolysis was also increased after the substrate was peroxidized by heat and O2. Similarly, peroxidation increased the rate of hydrolysis of soy PC liposomes that did not contain PE. In order to minimize
interfacial factors that may result in an increase in rate, the lipids were solubilized in Triton X-100. In mixtures of Triton
with soy PC in the absence of PE, peroxidation dramatically increased the rate of lipid hydrolysis. In addition, the rate
of hydrolysis of the unoxidizable lipid 1-palmitoyl-2-[1-14C]oleoyl PC incorporated into PC/PE liposomes was unaffected by peroxidation of the host lipid. These data are consistent
with the notions that the increase in rate of hydrolysis of peroxidized PC substrates catalyzed by phospholipase A2 is due largely to a preference for peroxidized phospholipid molecules as substrates and that peroxidation of host lipid does
not significantly increase the rate of hydrolysis of nonoxidized lipids. 相似文献
8.
Jiann-Tsyh Lin Carol L. Woodruff Olivier J. Lagouche Thomas A. McKeon Allan E. Stafford Marta Goodrich-Tanrikulu John A. Singleton Carol A. Haney 《Lipids》1998,33(1):59-69
We have examined the biosynthetic pathway of triacylglycerols containing ricinoleate to determine the steps in the pathway
that lead to the high levels of ricinoleate incorporation in castor oil. The biosynthetic pathway was studied by analysis
of products resulting from castor microsomal incubation of 1-palmitoyl-2-[14C]oleoyl-sn-glycero-3-phosphocholine, the substrate of oleoyl-12-hydroxylase, using high-performance liquid chromatography, gas chromatography,
mass spectrometry, and/or thin-layer chromatography. In addition to formation of the immediate and major metabolite, 1-palmitoyl-2-[14C]rici-noleoyl-sn-glycero-3-phosphocholine, 14C-labeled 2-linoleoyl-phosphatidylcholine (PC), and 14C-labeled phosphatidylethanolamine were also identified as the metabolites. In addition, the four triacylglycerols that constitute
castor oil, triricinolein, 1,2-diricinoleoyl-3-oleoyl-sn-glycerol, 1,2-diricinoleoyl-3-linoleoyl-sn-glycerol, 1,2-diricinoleoyl-3-linolenoyl-sn-glycerol, were also identified as labeled metabolites in the incubation along with labeled fatty acids: ricinoleate, oleate,
and linoleate. The conversion of PC to free fatty acids by phospholipase A2 strongly favored ricinoleate among the fatty acids on the sn-2 position of PC. A major metabolite, 1-palmitoyl-2-oleoyl-sn-glycerol, was identified as the phospholipase C hydrolyte of the substrate; however, its conversion to triacylglycerols was
blocked. In the separate incubations of 2-[14C]ricinoleoyl-PC and [14C]ricinoleate plus CoA, the metabolites were free ricinoleate and the same triacylglycerols that result from incubation with
2-oleoyl-PC. Our results demonstrate the proposed pathway: 2-oleoyl-PC. Out results demonstrate the proposed pathway: 2-oleoyl-PC→2-ricinoleoyl-PC→ricinoleate
→triacylglycerols. The first two steps as well as the step of diacylglycerol acyltransferase show preference for producing
ricinoleate and incorporating it in triacylglycerols over oleate and linoleate. Thus, the productions of these triacylglycerols
in this relatively short incubation (30 min), as well as the availability of 2-oleoyl-PC in vivo, reflect the in vivo drive to produce triricinolein in castor bean. 相似文献
9.
Marie-Aude Rouet-Mayer Olga Valentova Elizabeth Simond-Côte Jean Daussant Claudine Thévenot 《Lipids》1995,30(8):739-746
Using the spectrofluorimetric method described by Wittenaueret al. [Wittenauer, L.A., Shirai, K., Jackson, R.L., and Johnson, J.D. (1984)Biochem. Biophys. Res. Commun. 118, 894–901] for phospholipase A2 (PLA2) measurement, we have detected a phospholipase activity in Ailsa Craig and in mutantrin tomatoes at their normal harvest time (mature green stage). This activity in Ailsa Craig tomatoes increased at the beginning
of fruit ripening (green-orange stage) and then decreased slowly. The decrease in activity, however, was greater when ripening
occurred after tomato picking at normal harvest time than when ripening occurred on tomato plants. This phospholipase activity
was always higher inrin tomatoes than in normal ones. Thin-layer chromatography of compounds obtained after incubation of tomato extract demonstrated
a decrease in the substrate 1-acyl-2-{6[(7-nitro-2,1,3, benzoxadiazol-4-yl)amino]-caproyl}-sn-glycero-3-phosphocholine (C6-NBD-PC), and an increase in one product (NBD-aminohexanoic acid), but failed to detect the second product (1-acyl-sn-glycero-3-phosphocholine). We, therefore, developed a new one-step method for separation and quantification of a mixture
of phospholipids and other lipids, using straight-phase-high-performance liquid chromatography with light-scattering detection.
This method detected another fatty acid-releasing activity in enzyme extract from green-orange tomatoes. This lipolytic enzyme
(or family of enzymes) slowly produced free fatty acids when 1-oleoyl-sn-glycero-3-phosphocholine was added as substrate. The production of fatty acids was stoichiometric and more rapid when 1-oleoyl-sn-glycero-3-phosphate and 1-oleoyl-sn-glycerol were used as substrates. On the other hand, the same tomato extract was unable to hydrolyze 1,2-dioleoyl-sn-glycero-3-phosphate and 1,2-dioleoyl-sn-glycerol. Crude tomato extract exhibited lipid acyl hydrolase activity according to the definition of Galliard [Galliard,
T. (1979), inAdvances in the Biochemistry and Physiology of Plant Lipids (Appelqvist, L.A., and Liljenberg, C. eds.), pp. 121–132, Elsevier, Amsterdam]. But in order to demonstrate whether tomato
extract contains PLA2 activity and/or lysophospholipase activity, further work on purified tomato extract will be necessary. 相似文献
10.
Colantonio S Simpson JT Fisher RJ Yavlovich A Belanger JM Puri A Blumenthal R 《Lipids》2011,46(5):469-477
Since its introduction as an ionization technique in mass spectrometry, matrix-assisted laser desorption ionization (MALDI)
has been applied to a wide range of applications. Quantitative small molecule analysis by MALDI, however, is limited due to
the presence of intense signals from the matrix coupled with non-homogeneous surfaces. The surface used in nano-structured
laser desorption ionization (NALDI) eliminates the need for a matrix and the resulting interferences, and allows for quantitative
analysis of small molecules. This study was designed to analyze and quantitate phospholipid components of liposomes. Here
we have developed an assay to quantitate the DPPC and DC8,9PC in liposomes by NALDI following various treatments. To test our method we chose to analyze a liposome system composed of
DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and DC8,9PC (1,2-bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine), as DC8,9PC is known to undergo cross-linking upon treatment with UV (254 nm) and this reaction converts the monomer into a polymer.
First, calibration curves for pure lipids (DPPC and DC8,9PC) were created using DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) as an internal standard. The calibration curve for both DPPC and DC8,9PC showed an R2 of 0.992, obtained using the intensity ratio of analyte and internal standard. Next, DPPC:DC8,9PC liposomes were treated with UV radiation (254 nm). Following this treatment, lipids were extracted from the liposomes and
analyzed. The analysis of the lipids before and after UV exposure confirmed a decrease in the signal of DC8,9PC of about 90%. In contrast, there was no reduction in DPPC signal. 相似文献
11.
Moises Teles dos Santos Galo A. C. Le Roux Vincent Gerbaud 《Journal of the American Oil Chemists' Society》2011,88(2):223-233
Solid–liquid phase equilibrium modeling of triacylglycerol mixtures is essential for lipids design. Considering the α polymorphism
and liquid phase as ideal, the Margules 2-suffix excess Gibbs energy model with predictive binary parameter correlations describes
the non ideal β and β′ solid polymorphs. Solving by direct optimization of the Gibbs free energy enables one to predict from
a bulk mixture composition the phases composition at a given temperature and thus the SFC curve, the melting profile and the
Differential Scanning Calorimetry (DSC) curve that are related to end-user lipid properties. Phase diagram, SFC and DSC curve
experimental data are qualitatively and quantitatively well predicted for the binary mixture 1,3-dipalmitoyl-2-oleoyl-sn-glycerol (POP) and 1,2,3-tripalmitoyl-sn-glycerol (PPP), the ternary mixture 1,3-dimyristoyl-2-palmitoyl-sn-glycerol (MPM), 1,2-distearoyl-3-oleoyl-sn-glycerol (SSO) and 1,2,3-trioleoyl-sn-glycerol (OOO), for palm oil and cocoa butter. Then, addition to palm oil of Medium-Long-Medium type structured lipids is
evaluated, using caprylic acid as medium chain and long chain fatty acids (EPA-eicosapentaenoic acid, DHA-docosahexaenoic
acid, γ-linolenic-octadecatrienoic acid and AA-arachidonic acid), as sn-2 substitutes. EPA, DHA and AA increase the melting range on both the fusion and crystallization side. γ-linolenic shifts
the melting range upwards. This predictive tool is useful for the pre-screening of lipids matching desired properties set
a priori. 相似文献
12.
1-0-Hexadecyl-2-0-acetyl-sn-glycero-3-phosphocholine (platelet-activating factor) at 10−10-10−9 M induced slow contraction of isolated guinea-pig ilcal muscles and the contraction persisted for a long time. At a higher
concentration of 10−7 M, this phospholipid induced more rapid, but not greater, contraction. At higher concentrations (10−6-10−5 M), this phospholipid induced a biphasic response: rapid contraction followed by relaxation. At high concentrations, this
compound inhibited acetylcholine-induced contractions. The stimulatory effect of this phospholipid was ca. 300 times that
of 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine, while its inhibitory potency on induced contraction was similar to those of 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine and its lyso derivative. It was suggested that the differences in effects on contraction of different
concentrations of 1-0-hexadecyl- and 1-palmitoyl-2-0-acetyl-sn-glycero-3-phosphocholine were due to the dual effects of these compounds on the ileum: a strong stimulatory effect and a
moderate inhibitory effect on contraction. 相似文献
13.
Chiew-Hwee YeoSharif Hussein Sharif Zein Abdul Latif AhmadDavid S. McPhail 《Ceramics International》2012,38(1):561-570
The aim of this paper is to synthesise calcium phosphate (CaP) nanoshells by controlling their particle size and shape using negatively charged liposomes (1,2 dioleoyl-sn-glycero-3 phosphate sodium salt (DOPA) and 1,2-dipalmitoyl-sn-glycero-3-phosphate sodium salt (DPPA)) as a template. The morphology, particle size, size distribution and zeta potential properties of DOPA and DPPA liposome templates were determined. The results showed that both DOPA and DPPA formed spherical nanoshell structures to be used as templates for the synthesis of CaP nanoshells. By using the DOPA template, spherical CaPs structures with a mean particle size of 197.5 ± 5.8 nm were successfully formed. In contrast, needle or irregularly shaped CaP particles were observed when using the DPPA template. 相似文献
14.
Resolution of individual molecular species of human platelet 1,2-diradyl-sn-glycero-3-phosphocholines and 1,2-diradyl-sn-glycero-3-phosphoethanolamines by reverse phase high pressure liquid chromatography (HPLC) allowed a thorough analysis of
those phospholipids labeled with [3H]arachidonic acid. Approximately 54% and 16% of the total incorporated radiolabel was found in choline glycerophospholipids
and ethanolamine glycerophospholipids, respectively, with ca. 90% of this being found in the 1,2-diacyl molecular species.
Eighty percent of [3H]-arachidonic acid incorporated into 1-acyl-2-arachidonoyl-sn-glycero-3-phosphocholine in resting platelets was equally distributed between 1-palmitoyl-2-arachidonoyl and 2-stearoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, while 70% of the radiolabel in 1-acyl-2-arachidonoyl-sn-glycero-3-phosphoethanolamine was found in 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphoethanolamine. Thrombin stimulation (5 U/ml for 5 min) resulted in deacylation of all 1-acyl-2-[3H]arachidonoyl molecular species of 1-acyl-2-arachidonoyl-sn-glycero-3-phosphocholine and 1-acyl-2-arachidonoyl-sn-glycero-3-ethanolamine. There was also a slight increase in 1-O-alkyl-2-[3H]arachidonoyl-sn-glycero-3-phosphocholine and a significant increase in 1-O-alk-1′-enyl-2-[3H]arachidonoyl-sn-glycero-3-phosphoethanolamine molecular species of over 300%. Thus, HPLC methodology indicates that arachidonoyl-containing
molecular species of phosphatidylcholine and phosphatidylethanolamine are the major source of arachidonic acid in thrombin-stimulated
human platelets, while certain ether phospholipid molecular species become enriched in arachidonate. 相似文献
15.
Emilia Piosik Marta Ziegler-Borowska Dorota Cheminiak-Dudkiewicz Tomasz Martyski 《International journal of molecular sciences》2021,22(5)
An adsorption process of magnetite nanoparticles functionalized with aminated chitosan (Fe3O4-AChit) showing application potential in nanomedicine into cell membrane models was studied. The cell membrane models were formed using a Langmuir technique from three selected phospholipids with different polar head-groups as well as length and carbon saturation of alkyl chains. The research presented in this work reveals the existence of membrane model composition-dependent regulation of phospholipid-nanoparticle interactions. The influence of the positively charged Fe3O4-AChit nanoparticles on a Langmuir film stability, phase state, and textures is much greater in the case of these formed by negatively charged 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) than those created by zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC). The adsorption kinetics recorded during penetration experiments show that this effect is caused by the strongest adsorption of the investigated nanoparticles into the DPPG monolayer driven very likely by the electrostatic attraction. The differences in the adsorption strength of the Fe3O4-AChit nanoparticles into the Langmuir films formed by the phosphatidylcholines were also observed. The nanoparticles adsorbed more easily into more loosely packed POPC monolayer. 相似文献
16.
Drescher M Godschalk F Veldhuis G van Rooijen BD Subramaniam V Huber M 《Chembiochem : a European journal of chemical biology》2008,9(15):2411-2416
The putative function of the Parkinson's disease-related protein alpha-Synuclein (alphaS) is thought to involve membrane binding. Therefore, the interaction of alphaS with membranes composed of zwitterionic (POPC) and anionic (POPG) lipids was investigated through the mobility of spin labels attached to the protein. Differently labelled variants of alphaS were produced, containing a spin label at positions 9, 18 (both helix 1), 69, 90 (both helix 2), and 140 (C terminus). Protein binding to POPC/POPG vesicles for all but alphaS140 resulted in two mobility components with correlation times of 0.5 and 3 ns, for POPG mole fractions >0.4. Monitoring these components as a function of the POPG mole fraction revealed that at low negative-charge densities helix 1 is more tightly bound than helix 2; this indicates a partially bound form of alphaS. Thus, the interaction of alphaS with membranes of low charge densities might be initiated at helix 1. The local binding information thus obtained gives a more differentiated picture of the affinity of alphaS to membranes. These findings contribute to our understanding of the details and structural consequences of alphaS-membrane interactions. 相似文献
17.
The reactions of gaseous dinitrogen pentoxide (N2O5) and nitrogen dioxide (NO2) with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) coated on the inside surface of a glass reaction cell were studied at 298 K. Unsaturated
phosphatidylcholines are significant components of pulmonary surfactant in the alveolar region of the lung and hence serve
as a simple model to examine reactions of pulmonary surfactant with these oxidant air pollutants. Using high-performance liquid
chromatography (HPLC), Fourier transform infrared and fast atom bombardment mass spectroscopy, the major products of reactions
of POPC with N2O5 and NO2 were separated and identified. In the POPC-N2O5 reaction using either air or helium as a buffer gas, the nitronitrate, vinyl nitro and allylic nitro derivatives, as well
as a small amount of thetrans-isomer of the starting material, were obtained. The nature of the products obtained from the POPC-NO2 reaction depends on the concentration of NO2 as well as whether air is present. At low NO2 concentrations (PNO
2/N
2O4≤3.8 Torr) in air or in helium, thetrans-isomer of POPC was formed almost exclusively. At higher NO2 concentrations (PNO
2/N2O4≥20 Torr) in helium, the dinitro, vinyl nitro and nitro alcohol derivatives were formed. In the presence of air (or 24%18O2 in helium), a nitronitrate and a dinitronitrate were additional products. Mechanisms for the formation of the observed products
and implications for the inhalation of oxides of nitrogen are discussed. 相似文献
18.
The molecular species composition of the major glycerophospholipids from white matter of human brain were determined by high-performance
liquid chromatography of the 3,5-dinitrobenzoyl derivatives of the corresponding diradylglycerols. In phosphatidylcholine
(PC) and phosphatidylserine (PS), molecular species containing only saturated fatty acids (SFA) and monounsaturated fatty
acids (MUFA) comprised 85.7 and 82.4% of the respective totals, with 18∶0/18∶1 predominant in PS and 16∶0/18∶1 in PC. These
molecular species were also abundant in phosphatidylethanolamine (PE), but in this phospholipid species containing polyunsaturated
fatty acids (PUFA), largely 18∶0/22∶6n−3 and 18∶0/20∶4n−6, accounted for over half the total; 18∶1/18∶1 was also abundant
in PE. In contrast, 1-O-alk-1′-enyl-2-acylsn-glycero-3-phosphoethanolamine (GPE) had much more SFA- and MUFA-containing species, predominantly 16∶0a/18∶1, 18∶0a/18∶1
and 18∶1a/18∶1, with low amounts of species containing 20∶4n−6 and 22∶6n−3. In alkenylacyl GPE, 22∶4n−6 was the major PUFA
and 16∶0a/22∶4n−6 and 18∶1a/22∶4n−6 the main PUFA-containing species. There was six times more 22∶6n−3, twice as much 20∶4n−6
and half the amount of 22∶4n−6 in PE as compared to alkenylacyl GPE.
Molecular species are abbreviated as follows:e.g., 16∶0/18∶1 PE is 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine; the corresponding alkenylacyl species, 1-O-hexadec-1′-enyl-2-oleoyl-sn-glycero-3-phosphoethanolamine is 16∶0a/18∶1. 相似文献
19.
Formation of novel thermo-responsive hybrid vesicles: influence of molar ratio of lipids and heating
Thermo-responsive triblock copolymer, [poly(2-isopropyl-2-oxazoline)-b-poly(dimethylsiloxane)-b-poly(2-isopropyl-2-oxazoline] (IDI) was synthesized, for the first time, by ring opening polymerization and it can self-assemble in to polymersome in aqueous solution. We demonstrate a simple route to develop the novel hybrid vesicles, from the IDI and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), by systematically regulating the molar ratio of DMPC. Effect of heating on the hybrid vesicular solution has also been examined. Differential scanning calorimetry (DSC), dynamic light scattering and fluorescence spectroscopy were used to investigate the role of molar ratio of DMPC and heating time of the mixture on the formation of hybrid vesicles. From DSC measurements, we interestingly found that heating the mixture of IDI and DMPC enhanced the insertion of IDI into the membrane of liposomes. The present findings confirm the potential utility of hybrid vesicular systems for the design of functional hybrid materials and could be used for controlled drug delivery applications. 相似文献
20.
Ethanolamine glycerophospholipids from the brains of both trout and cod comprised 36–38% of 1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine (GPE) determined using two methods. In 1-O-alk-1′-enyl-2-acyl-GPE from trout brain, the main molecular species were 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1, which totalled
63.3%, while polyunsaturated fatty acid (PUFA) containing species totalled only 18.2%. 1-O-Alk-1′-enyl-2-acyl-GPE from cod brain was much more unsaturated with PUFA containing species totalling 52.6%, of which 18∶0a/20∶5n−3,
18∶1a/20∶5n−3 and 18∶1a/22∶6n−3 were predominant. In cod 18∶1a/18∶1, 18∶0a/18∶1 and 16∶0a/18∶1 were the only other species
present at over 5% each, totalling 31.8%. In both cod and trout, small amounts of species containing 22∶4n−6 were found. The
results of this and earlier studies indicate that there is considerable specificity of composition at the level of molecular
species between different lipid classes and subclasses.
Molecular species of 1-O-alk-1′-enyl-2-acyl-GPE are abbreviated as follows:e.g., 16∶0a/18∶1 GPE is 1-O-hexadec-1′-enyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. The corresponding diacyl species, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine, is abbreviated as 16∶0/18∶1. 相似文献