Rapid enzyme-induced hydrolysis of microgram amounts of phosphatidylcholine on phospholipase A2/celite columns

A method has been developed to hydrolyze microgram amounts of phosphatidylcholine (PC) regiospecifically. Hydrolysis of thesn-glycerol 2-acyl group occurs rapidly on microcolumns of immobilized phospholipase A₂ on Celite 545 diatomaceous earth. Close to 90% reaction occurs within the first 5 min. Acyl group analysis then may be accomplished by gas liquid chromatography (GLC) of the resulting fatty acids. Hydrolysis of α-16∶0-β-14∶0 PC demonstrated consistent selectivity for 14∶0 liberation, with small amounts of 16∶0 probably indicative of acyl scrambling during the synthesis of the PC. Hydrolysis of an equal weight mixture of (14∶0)₂ PC and (18∶2)₂PC demonstrated nonpartiality of the immobilized enzyme for either a saturated or unsaturated substrate. The new methodology offers a convenient and sensitive alternative to the presently used procedures. Presented at the AOCS 68th Annual Meeting, New York, May 1977. Reference to brand or firm name does not constitute endorsement by the U.S. Department of Agriculture over others of a similar nature not mentioned.     

Separation of monoacylglycerols by high-performance liquid chromatography on nitrile-bonded phase

Monoacylglycerol molecular species, as their di-3,5-dinitrophenylurethane derivatives, were well separated by normalphase high-performance liquid chromatography on nitrilebonded phase. The peaks emerged in the order 20∶0, 18∶0, 16∶0, 18∶1, 16∶1, 18∶2, and 18∶3. The peaks of 1- and 2-monoacylglycerols with the same acyl group showed complete overlapping. This method could be applied to get acyl compositions in the three positions of triacyl-sn-glycerols in their stereospecific analysis. Presented partially at the 83rd AOCS Annual Meeting held in Toronto, Canada, May 10–14, 1992.     

Properties of lysophosphatidylcholine acyltransferase from <Emphasis Type="Italic">Brassica napus</Emphasis> cultures

Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT; EC 2.3.1.23) catalyzes the acyl-CoA-dependent acylation of lysophosphatidylcholine (LPC) to produce PC and CoA. LPCAT activity may affect the incorporation of fatty acyl moieties at the sn-2 position of PC where PUFA are formed and may indirectly influence seed TAG composition. LPCAT activity in microsomes prepared from microspore-derived cell suspension cultures of oilseed rape (Brassica napus L. cv Jet Neuf) was assayed using [1-¹⁴C]acyl-CoA as the fatty acyl donor. LPCAT activity was optimal at neutral pH and 35°C, and was inhibited by 50% at a BSA concentration of 3 mg mL⁻¹. At acyl-CoA concentrations above 20 μM, LPCAT activity was more specific for oleoyl (18∶1)-CoA than stearoyl (18∶0)- and palmitoyl (16∶0)-CoA. Lauroyl (12∶0)-CoA, however, was not an effective acyl donor. LPC species containing 12∶0, 16∶0, 18∶0, or 18∶1 as the fatty acyl moiety all served as effective acyl acceptors for LPCAT, although 12∶0-LPC was somewhat less effective as a substrate at lower concentrations. The failure of LPCAT to catalyze the incorporation of a 12∶0 moiety from acyl-CoA into PC is consistent with the tendency of acyltransferases to discriminate against incorporation of this fatty acyl moiety at the sn-2 position of TAG from the seed oil of transgenic B. napus expressing a medium-chain thioesterase.     

Esterified lipids of the freshwater dinoflagellatePeridinium lomnickii

Steryl esters, phytyl esters and triacylglycerols of a naturally occurring freshwater dinoflagellate,Peridinium lomnickii, were identified using capillary gas chromatography-mass spectrometry (GC-MS). Steryl esters differing in degree of unsaturation were separated, prior to analysis, by argentation thin layer chromatography. 5α(H)-Cholestanol was more dominant, relative to 4α-methylstanols, in steryl esters than in the free sterols, but the same sterol moieties occurred in both fractions. Monoenoic fatty acids were enriched in the steryl esters relative to the free fatty acids. Major acyl groups in steryl esters were 16∶0 or 20∶1, with smaller amounts of 14∶0 and 18∶1. In triacylglycerols the acyl moieties were 14∶0, 16∶0, 18∶1, 16∶1 and 12∶0, in order of decreasing abundance. Phytyl esters, previously inferred to occur in a marine dinoflagellate only by analysis of transesterified products, were identified by GC-MS comparison with authentic compounds. Direct analysis of these esterified lipids has not been reported for freshwater phytoplankton. The 4α-methylstanyl esters, 5α(H)-cholestan-3β-yl esters and phytyl esters occurring inP. lomnickii are further features in common with marine dinoflagellates, additional to the 4α-methylsterols reported previously.     

Acyl moieties modulate the effects of phospholipids on β-carotene uptake by Caco-2 cells

The intestinal absorption of carotenoids is though to be mediated by the carotenoid assembly in mixed micelles, followed by its transfer into the enterocytes and subsequent secretion to the lymph as chylomicron particles. In the present study we investigated the effects of phospholipids and lysophospholipids with diverse fatty acyl moieties on the uptake of β-carotene solubilized in mixed micelles by Caco-2 cells. Compared with phospholipid-free mixed micelles (NoPL), those containing long-chain PC inhibited β-carotene uptake (16∶0, 18∶1-PC≅16∶0, 18∶2-PC<14∶0, 14∶0-PC≅16∶0, 14∶0-PC <16∶0, 16∶0-PC<NoPL). However, mixed micelles containing medium-chain PC enhanced β-carotene uptake (NoPL<8∶0, 8∶0-PC<12∶0, 12∶0-PC<10∶0, 10∶0-PC), and short-chain PC did not affect the uptake. Among the lysophosphatidylcholine (LysoPC) class, a marked increase of β-carotene uptake by medium-to-long-chain LysoPC was observed (NoPL<12∶0-LysoPC<14∶0-LysoPC<18∶1-LysoPC<16∶0-LysoPC), although short-to-medium-chain LysoPC (6∶0-LysoPC to 10∶0-LysoPC) did not affect β-carotene uptake. The long-chain 16∶0,18∶1-PC increased the β-carotene efflux from cells and drastically changed the β-carotene UV-visible absorbance spectrum, compared with those of NoPL micelles. The acyl moieties of long-chain PC may interact with the carotenoid in the micelle interior, shifting the β-carotene partition toward the micellar phase. Medium-chain PC and long-chain LysoPC, which have nearly equivalent hydrophobicities, may enhance β-carotene uptake through their interaction with the cell membrane.     

Phosphatidylcholine hydroperoxide levels in human plasma are lower than previously reported

The quantification of PC hydroperoxide (PCOOH) in human plasma was studied by HPLC with chemiluminescence detection (HPLC-CL). We identified for the first time the monohydroperoxide of 1-palmitoyl-2-linoleoyl-PC hydroperoxide (PC 16∶0/18∶2-OOH) in plasma by LC-MS and HPLC-CL. The standard compound, PC 16∶0/18∶2-OOH (synthetic PCOOH), as well as PCOOH from egg yolk, was used. Comparison of the PCOOH concentration in each participant's plasma as determined by use of a Finepak SIL NH₂ column with 2-propanol/methanol/water as the mobile phase (system A, the conventional method) gave a higher concentration than did an LC-18-DB column with methanol containing 0.01% triethylamine (system B). The mean PCOOH concentration for the 43 healthy volunteers was 55.1±30.4 pmol/mL (mean±SD) for system A and 16.3±9.9 pmol/mL for system B. Moreover, the main peak of the plasma extract appeared at a different time from that of synthetic PCOOH or egg yolk PCOOH in system A, whereas in system B plasma sample retention time practically corresponded to that of standard PCOOH. These findings confirm that the PCOOH plasma concentration is not so high as previously reported.     

Selective deposition oftrans-8- andcis-9-octadecenoates in egg and tissue lipids of the laying hen

The deposition oftrans-8-octadecenoate-8(9)-³H (8t-18∶1-³H) was compared tocis-9-octadecenoate-10-¹⁴C (9c-18∶1-¹⁴C) in the major egg yolk neutral lipids and phospholipids and in organ lipids from the laying hen.trans-8-Octadecenoate was preferentially incorporated into only the phosphatidylethanolamines (PE), whereas discrimination against 8t-18∶1-³H occurred in the phosphatidylcholines (PC), triglycerides (TG) and cholesteryl esters (CE). The 1-acyl position of both PE and PC contained three times more 8t-18∶1-³H than 9c-18∶1-¹⁴C. Almost total exclusion of the 8t-18∶1-³H from the 2-acyl position of these phospholipids was found. Preferential incorporation of 9c-18∶1-¹⁴C occurred at the combined 1- and 3-acyl positions and at the 2-acyl position of yolk TG. Tissue lipid analyses indicated that there was preferential deposition of 9c-18∶1-¹⁴C into all organs. Individual liver lipid classes displayed the same relative order of discrimination against 8t-18∶1-³H as did egg yolk lipids (CE>TG>PC>PE).     

On the membrane phospholipids and their acyl group profiles of adrenal gland

The phospholipid composition and their acyl group profiles from subcellular fractions of guinea pig adrenal gland and the same fractions from the cortex and medulla of the bovine gland were compared. The phospholipids of guinea pig adrenal were enriched in diacyl-glycerophosphocholines (GPC) which comprised over 50% of the total phospholipids, but the proportions of ethanolamine and choline plasmalogens, sphingomyelin and diacyl-glycerophosphoserine (GPS) were lower in guinea pig adrenals as compared to the bovine adrenals. In the bovine adrenal, sphingomyelin and diacyl-GPS were enriched in the medulla, whereas diacyl-glycerophosphoinositol (GPI) were enriched in the cortex. Although lysolecithin was present (up to 4.5%) in the bovine adrenal, only trace amounts of this lipid were detected in the guinea pig adrenal. Characteristic acyl group profiles were found associated with each type of the phosphoglycerides in adrenal membranes. However, acyl group profiles of the phosphoglycerides were not greatly different either between the bovine and guinea pig adrenal or with respect to the type of subcellular membranes isolated. Diacyl-GPC were enriched in 16∶0 and 18∶1, but also contained considerable amounts of 18∶0, 18∶2 and 20∶4. Diacyl-GPE were enriched in 18∶0, 18∶1 and 20∶4, while diacyl-GPI, diacyl-GPS, as well as alkenylacyl-GPE, were enriched in 20∶4. The lysolecithin from bovine adrenal membranes contained mainly 16∶0, 18∶0 and 18∶1 with only trace amounts of the polyunsaturated fatty acids. Other polyunsaturated fatty acids, such as 22∶4 and 22∶6, are apparently not prominent in the phosphoglycerides from either the bovine or the guinea pig adrenal gland.     

Changes in phosphatidylcholine molecular species in the shrimp <Emphasis Type="Italic">Macrobrachium borellii</Emphasis> in response to a water-soluble fraction of petroleum

The effect of the water-soluble fraction (WSF) of crude oil on lipid contents, lipid classes, FA, and PC molecular species was studied in high-phospholipid (hepatopancreas) and low-phospholipid (egg) tissues of a freshwater crustacean. After a 21-d exposure to a sublethal concentration of WSF, a significant decrease in shrimp total lipids was observed, although no alterations could be detected in the hepatopancreas or egg lipid contents. TAG/phospholipid ratios increased in the hepatopancreas and decreased in the eggs, suggesting alterations either in the mobilization of TAG to phospholipid pools or in the energy balance. The FA composition of phosphoglycerides in the hepatopancreas and eggs was dominated by PUFA, whereas the n−3/n−6 ratio was not affected by WSF exposure, although there was a significant increase in hepatopancreas 18∶1n−9. Analysis of the PC molecular species by HPLC-ELSD showed the presence of 15 species, with 16∶0/18∶1, 18∶1/18∶2, 16∶0/20∶5, and 16∶1/20∶5 being the major species in the hepatopancreas. The PC molecular species in the eggs showed a different pattern, dominated by 16∶0/18∶1 and 18∶1/18∶2. Of the PC molecular species, 10 contained 22∶6n−3, 20∶5n−3, and 20∶4n−6. Small amounts of di-PUFA species were also found. Exposure to WSF altered the PC molecular species in both tissues. The four major hepatopancreas molecular species and most of the ones containing PUFA decreased. This was compensated for by an increase in 16∶1/18∶1 (152%) and 18∶1/18∶1 (50%). The two major egg PC molecular species decreased, whereas the PUFA-containing ones increased. The contrasting responses of both tissues of WSF contamination suggests the presence of different homeostatic mechanisms.     

High pressure liquid chromatographic separation of molecular species of phosphatidic acid dimethyl esters derived from phosphatidylcholine

A majority of the individual molecular species of phosphatidic acid dimethyl esters derived from multispecies egg yolk and soybean phosphatidylcholines have been separated by reverse-phase high pressure liquid chromatography. Two Partisil-10 ODS columns connected in tandem and the eluents acetonitrile or methanol/water (95∶5) were used for molecular species resolution, based on total fatty acyl carbon number and degree of unsaturation.     

Fatty acid composition of the adipose tissue and yolk lipids of a bird with a marine-based diet, the emperor penguin (Aptenodytes forsteri)

The emperor penguin (Aptenodytes forsteri) is an Antarctic seabird feeding mainly on fish and therefore has a high dietary intake of n-3 polyunsaturated fatty acids. The yolk is accumulated in the developing oocyte while the females are fasting, and a large proportion of the fatty acid components of the yolk lipids are derived by mobilization from the female's adipose tissue. The fatty acid composition of the total lipid of the yolk was characterized by high levels of n-3 polyunsaturated fatty acids. However, it differed in several respects from that of the maternal adipose tissue. For example, the proportions of 14∶0, 16∶1n−7, 20∶1n−9, 22∶1n−9, 20∶5n−3, and 22∶6n−3 were significantly greater in adipose tissue than in yolk. Thus adipose tissue lipids contained 7.6±0.3% and 8.0±0.3% (wt% of total fatty acids; mean ±SE; n=5) of 20∶5n−3 and 22∶6n−3, respectively, whereas the yolk total lipid contained 1.6±0.1 and 5.5±0.3% of these respective fatty acids. The proportions of 16∶0, 18∶0, 18∶1n−9, 18∶2n−6, and 20∶4n−6 were significantly lower in the adipose tissue than in the yolk lipids. The proportions of triacylglycerol, phospholipid, free cholesterol, and cholesteryl ester in the yolk lipid were, respectively, 67.0±0.2, 25.4±0.3, 5.3±0.2, and 1.8±0.2% (wt% of total yolk lipid). The proportions of 20∶4n−6, 20∶5n−3, 22∶5n−3, and 22∶6n−3 were, respectively, 5.7±0.3, 2.8±0.2, 1.4±0.1, and 11.7±0.5% in phospholipid and 0.4±0.0, 1.2±0.1, 0.8±0.1 and 3.6±0.3% in triacylglycerol. About 95% of the total vitamin E in the yolks was in the form of α-tocopherol with γ-tocopherol forming the remainder. Two species of carotenoids, one identified as lutein, were present.     

Effects of phosphatidylcholines on de novo synthesis and excretion of sterol by L-929 fibroblasts

The effects on [¹⁴C] sterol synthesis and excretion by exposure of L-929 cells to several phosphatidylcholines (PC) has been examined. No significant effects were noted on either parameter during a 6-hr period if exposure of cells to the phospholipid preceded the addition of [1-¹⁴C] acetate by just 30 min. However, if cultures were grown in media containing delipidized serum and 2×10⁻⁵ M PC through 2 or more subculturings prior to adding [1-¹⁴C] acetate, the amount of [¹⁴C] sterol increased in both cells and medium by 70–200% when saturated or monounsaturated PC were used. Dilinoleylphosphatidylcholine (18∶2 PC) at the same concentration did not stimulate synthesis or excretion of newly synthesized sterol. Total cellular sterol was determined by gas chromatography, and was only marginally affected by long-term exposure to dipalmitylphosphatidylcholine (16∶0 PC), whereas the total sterol of the medium increased by 4-fold over a 19-hr period. Cultures which had been exposed to 16∶0 PC through 3 subculturings continued to display enhanced de novo sterol synthesis, but not excretion, for up to 5 hr after replacement with fresh medium lacking 16∶0 PC. The disparity in response to 2×10⁻⁵ M levels of 16∶0 PC and 18∶2 PC may relate to differences in metabolism of cellular fatty acids, whereas relatively small changes in the cellular fatty acid composition were noted with 16∶0 PC-treated cells. The results indicate that extracellular PC can promote sterol synthesis and excretion by L-929 cells, and that the magnitude of this response is influenced by the time of exposure to the phospholipid and by its fatty acid composition.     

Competitive deposition oftrans-12- andcis-9-octadecenoates into egg yolk lipids

The deposition oftrans-12-octadecenoate-12(13)-³H (12t-18∶1-³H) was compared tocis-9-octadecenoate-10-¹⁴C (9c-18∶1-¹⁴C) in the major egg yolk neutral lipids and phospholipids.trans-12-Octadecenoate was preferentially incorporated into cholesteryl esters (CE), phosphatidylcholines (PC), and phosphatidylethanolamines (PE) but was discriminated against in triglycerides (TG). Isotopic ratios indicate that 5.9 and 5.6 times more 12t-18∶1-³H than 9c-18∶1-¹⁴C was esterified at the 1-acyl position of PE and PC, respectively. The combined 1- and 3-acyl positions of TG and the 2-acyl position of TG, PE and PC were each preferentially esterified with 9c-18∶1-¹⁴C.     

Fatty acid positional distribution in egg yolk triglycerides from various avain species

The fatty acid composition and distribution in egg yolk triglycerides and phosphatides from the turkey, duck, prairie chicken, bobwhite quail, Japanese quail, and inbred-hybrid and midget mutant hens were determined after all species had been fed diets of similar fat and fatty acid content for 90 days. Total volk lipids were composed of ca. two-thirds neutral lipids and one-third polar lipids. The predominant fatty acids were palmitic and stearic. There were statistically significant differences in the my ristic, palmitic, palmitoleic, linoleic, and linolenic acids in the yolk triglycerides and in the proportion of 16∶1, 18∶0, 18∶2, arachidonic, docosanoic, docosahexaenoic, and tetracosanoic acids in the phosphatides among the various species. Linoleic acid predominantly was linked at the 2-position in the yolk triglycerides followed by the 20∶4 acid. The 18∶1 acid also was found preferentially at the 2-position. There was a low level of 18∶2 in the yolk triglycerides and phosphatides from the duck and an especially high level of 20∶4 acid in the phosphatides. The triglycerides in the species studied have essentially the same distribution of fatty acids in the 2-position. In all the species, the affinity for the fatty acids at the 2-position is in the following order: 18∶2=20∶4>18∶1 =18∶3>18∶0=16∶1>14∶0>16∶0 Differences observed among the various genera did not appear to follow taxonomic boundaries. The duck has an efficient system for converting 18∶2 into 20∶4 by elongation and desaturation. The prairie chicken apparently has a high requirement for 18∶2 but an inadequate system for its conversion into 20∶4.     

Effect of diet on triglyceride structure and composition of egg yolk lipids

Hens were fed a practical diet supplemented and unsupplemented with 5% menhaden oil and a synthetic fat-free diet for a period of 90 days. Egg yolks from hens fed each of the three diets were analyzed for fatty acid composition and positional distribution of the fatty acids by successive chromatographic techniques. The triglycerides were resolved into fractions containing, 0, 1, 2 and 3+ double bonds per molecule. Each of these types was quantitated and analyzed for fatty acid distribution. The positional distribution was determined with the aid of pancreatic lipase hydrolysis. The feeding of the practical diet supplemented with 5% menhaden oil produced an increase in the 14∶0 acid in the intact triglycerides, 2-monoglycerides and 1,3-diglycerides with the majority of this acid being bound in the 1,3 positions. In the monounsaturated triglycerides the 16∶0 acid was linked predominantly at the 1,3 positions. The feeding of the fat-free diet produced a decrease in the 16∶1 acid content of the egg yolk lipids in the monounsaturated series, in the intact triglycerides, the 2-monoglycerides and the 1,3-diglycerides. The 18∶0 acid was linked more often at the 1,3 positions than at the 2 position, and was not affected by the diet consumed by the hens. Hens fed the fat-free diet produced more monounsaturated and diunsaturated triglycerides than those fed the other diets. Linoleic acid exhibited the greatest degree of preference for the 2 position, which was followed in turn by oleic acid. All other major acyl components were found to be preferentially esterified at the 1,3 positions. The difference observed in the fatty acid composition of egg yolk neutral and polar lipids was attributable to the fatty acid content of the diet. In the case of the oleic and linoleic acids, there was less variation in the saturated fatty acid content, which could be traced to the type of diet fed.     

Structural analysis of hydroperoxides formed by oxidation of phosphatidylcholine with singlet oxygen

Soybean phosphatidylcholine (PC) and dilinoleoyl PC (di-18∶2 PC) were oxidized with singlet molecular oxygen using methylene blue as the photosensitizer. The oxidation products, PC monohydroperoxides (PC-MHP) and PC dihydroperoxides (PC-DHP), were isolated by reverse phase liquid chromatography, and their structures were analyzed by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS). Signals for the hydroperoxy proton appeared downfield in NMR spectra of PC-MHP and PC-DHP. Soybean PC-MHP and di-18∶2 PC-MHP were converted to trimethylsilyl (TMS) derivatives of hydrogenated diglycerides when treated with phospholipase C and hydrogenated. Thetert-butyldimethylsilyl (TBDMS) derivatives of hydrogenated diglycerides were also prepared from di-18∶2 PC-MHP. Fragmentation of the TMS and TBDMS derivatives was obtained in electron impact mass spectra. The isomeric composition of hydroperoxylinoleate component in di-18∶2 PC-MHP was determined by methanolysis of the hydrogenated diglyceride and mass chromatographic analysis of the resulting isomeric hydroxy octadecanoates.     

The effect of the refining process on the interfacial properties of palm oil

The interfacial tension of palm oil against water at 60°C was determined in the presence of monoglycerides with (i) different acyl chain lengths, (ii) the same acyl chain length but with different unsaturation, and (iii) different phospholipids. The interfacial tensions of the oil/water interface were depressed, albeit to different extents, by the presence of these substances, depending on the acyl chain length, unsaturation, and the chemical structure of the species adsorbed. The adsorption of the saturated monoglycerides C12∶0, C14∶0, C16∶0, C18∶0 and the unsaturated monoglycerides of C18∶1 and C18∶3 is consistent with a Langmuir isotherm at the palm oil/water interface. However, fitting of the data for C18∶2, l-α-phosphatidylcholine, and lysophosphatidylcholine to the Langmuir isotherm is less satisfactory. The surface areas of the materials adsorbed at the palm oil/water interface are much larger than those of liquid condensed films and closer to those for liquid expanded films. The influence of the nature of the oil (triglycerides), the minor components in the oil, and thier interactions with the added lipids at the oil/water interface are briefly discussed. The effect of the refining process on the interfacial properties of palm oil against water was also studied. The efficiency of the refining process in minor oil contaminants’ removal and the quality of the oil obtained as reflected by the interfacial properties of the oil is discussed.     

Effect of browning reaction products of phospholipids on autoxidation of methyl linoleate

Methyl linoleate was allowed to autoxidize in bulk phase at 50 C in the presence of either synthetic phospholipids consisting of saturated fatty acids or egg yolk phospholipids to estimate the effect of base group and fatty acid moiety of phospholipids on oil autoxidation. Dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylethanolamine (DPPE) exhibited poor antioxidant activity at 50 C and showed no synergistic effect with α-tocopherol. The addition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of egg yolk accelerated the oxidation of methyl linoleate. However, egg yolk PC and PE collected at various stages of heating at 180 C inhibited hydroperoxide formation at the initial stage of oxidation. This effect could be attributed to the browning products formed during heating reaction. Thus, browning color products formed from unsaturated phospholipids at high temperatures may influence oil stability, although the base group of phospholipids did not exert any significant effect.     

The acyl and Alk-1-enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal,mitochondrial and myelin fractions

The major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions were separated by preparative thin layer chromatography. Alk-1-enyl groups from the alk-1-enyl acyl glycerophosphorylethanolamines were reacted with 1,3-propanediol to form the 1,3-dioxolane derivatives. Acyl groups were converted to the methyl ester derivatives and the acyl groups from alk-1-enyl acyl glycerophosphorylethanolamines and diacyl glycerophosphorylethanolamines were also determined separately. The acyl and alk-1-enyl group compositions of the phosphoglycerides from microsomal and mitochondrial fractions were quite similar. The ethanolamine and serine phosphoglycerides contained large amounts of 18∶0, 18∶1, 20∶4 and 22∶6 acyl groups. The choline phosphoglycerides had small amounts of polyunsaturated acyl groups and large amounts of 16∶0, 18∶1 and 18∶0 acyl groups. The mitochondrial cardiolipins contained unusual amounts of several acyl groups including 18∶1, 52%; 18∶2, 6%; and 16.1, 4%. A large portion of the mouse brain 18∶2 is in that fraction. The myelin phosphoglycerides were deficient in saturated and 22∶6 groups and markedly enriched in 18∶1 and 20∶1 groups when compared with the corresponding microsomal or mitochondrial phosphoglycerides. Presented in part at the AOCS Meetings, New York, October 1968 and San Francisco, April 1969.     

Omega-3 fatty acid and cholesterol content of newly hatched chicks from α-linolenic acid enriched eggs

Egg yolk was enriched with α-linolenic acid (18∶3n−3) by feeding laying hens diets containing flax, canola or soybean seeds. Fertilized eggs were incubated and the fatty acid composition of whole body, liver, plasma, brain and the cholesterol content of plasma and liver tissue of the hatched chicks were studied. Eggs enriched with 18∶2n−6 fatty acids by feeding hens diets containing sunflower seeds were used as the controls. Feeding flax enriched (P<0.05) egg yolk and the developing progeny with 18∶3n−3, 20∶5n−3, 22∶5n−3 and 22∶6n−3. Feeding sunflower seeds resulted in an increase (P<0.05) of 18∶2n−6, 20∶4n−6, 22∶4n−6 and 22∶5n−6. The predominant polyunsaturated fatty acid of the brain was docosahexaenoic acid (22∶6n−3) which was higher (P<0.05) in the flax and canola fed group. The cholesterol content of the liver tissue was lower (P<0.05) in chicks hatched from hens fed flax seeds. This study indicates that 18∶3n−3 and 18∶2n−6 in the maternal diet are potent modulators of long-chain polyunsaturated n−3 or n−6 fatty acid and of cholesterol content in the developing progeny.