Generation of phospholipid artefacts during extraction of developing soybean seeds with methanolic solvents

The major phospholipids of soybean cotyledons during development were phosphatidylcholine (45–55%), phosphatidylethanolamine (24–28%), and phosphatidylinositol (15–18%) when the tissue was steam-killed prior to extraction of the lipids. The only other phospholipids of any significance (4–6%) was identified as phosphatidylglycerol. Phosphatidic acid was a minor constituent (<1%), and neither N-acyl phosphatidylethanolamine norbis-phosphatidic acid were detected in appreciable (>0.1% of the total lipid phosphorus) quantities. When fresh cotyledons were rapidly homogenized in mixtures of chloroform and methanol or in methanol alone, phosphatidylmethanol was formed in variable amounts (0–20% of the total phospholipid), and when cotyledons were soaked in methanol prior to homogenizing, phosphatidylmethanol became the major phospholipid, accounting for up to 75% of the total lipid phosphorus. Phosphatidylmethanol was formed by the phospholipase D-catalyzed transphosphatidylation of phosphatidylcholine and phosphatidylethanolamine during extraction.     

Determination of the phospholipid composition of trout gill by latroscan TLC/FID: Effect of thermal acclimation

The phospholipid composition of gill tissue from thermally acclimated rainbow trout,Salmo gairdneri, was determined by Iatroscan analysis following an initial development of the chromarods in a non-polar solvent to remove neutral lipids. Standard curves for all phospholipids, although linear through most of the concentration range tested (1–40 μg), extrapolated to negative intercepts on the ordinate, indicating a decline in sensitivity at low phospholipid levels. In addition, the concentration dependence of the Iatroscan response varied by nearly 6-fold among phospholipids. Of the major phospholipids, only lysophosphatidylcholine could not be quantitated accurately because of the presence of an interfering peak. Quantitation by Iatroscan yielded results which, in general, agreed well (within 5%) with results obtained by an independent phosphate analysis. Only in the case of phosphatidylinositol (PI) did the two analytical methods differ significantly; proportions of PI were 55% higher when determined by Iatroscan as opposed to phosphate analysis. Gill tissue from 5 C-acclimated trout possessed higher proportions of phosphatidylethanolamine than tissue from 20 C-acclimated trout. The Iatroscan provided a rapid and reliable means of quantitating the proportions of all the major phospholipids of trout gill, although there are some limitations to the general applicability of the technique.     

Influences of subzero thermal acclimation on mitochondrial membrane composition of temperate zone marine bivalve mollusks

The phospholipid and phospholipid fatty acid composition of gill mitochondrial membranes from two temperate zone marine bivalve mollusks, the quahog, Mercenaria mercenaria, and the American oyster, Crassostrea virginica, were examined after acclimation to 12 and −1°C. Cardiolipin (CL) was the only phospholipid with proportions altered upon acclimation to −1°C, increasing 188% in the mitochondrial membranes of M. mercenaria. Although the ratio of bilayer stabilizing to destabilizing lipids is frequently associated with cold acclimation in ectothermic species, no change was found in this ratio in either of the species. Polyunsaturated fatty acids (PUFA) were found only to increase in C. virginica with cold acclimation, with total n-3 PUFA increasing in the phospholipid phosphatidylethanolamine, total n-6 PUFA increasing in CL, and total PUFA increasing in phosphatidylinositol. Monounsaturated fatty acids, not PUFA, were found to have increased in M. mercenaria, with 18:1n−9 increasing by 150% in CL, and 20∶1 increasing in both CL and phosphatidylcholine, by 146 and 192%, respectively. These manipulations of membrane phospholipid and fatty acid composition may represent an attempt by these species to help maintain membrane function at low temperatures.     

The lipid composition of microsomal preparations from lactating bovine mammary tissue

The microsomes isolated from lactating bovine mammary tissue contained 4.3 mg lipid per milligram nitrogen. Phospholipids comprised 83% of the lipids. The neutral lipids were composed of triglycerides (20–30%), diglycerides (5–10%), free fatty acids (15–30%, cholesterol (35–40% and cholesterol esters (10–12%, respectively. Phosphatidylcholine was the predominant phospholipid component (>50%), and the remainder consisted of phosphatidylethanolamine (21–13%), phosphatidylserine (4–6%), phosphatidylinositol (8%), sphingomyelin (9%) and lysophosphatidylcholine (2%) respectively. The composition of the microsomal phospholipids was similar to that of isolated mammary cells and tissue homogenates but quite different from milk and fat globule membrane phospholipids. The triglycerides contained short chain fatty acids but their relative concentrations were lower than in milk triglycerides. The various lipid fractions had a variable proportion of saturated fatty acids, i.e., triglycerides (47.7%), diglycerides (86.7%), free fatty acids (70.6%), phosphatidylcholine (50.6%), phosphatidylethanolamine (50.8%), phosphatidylserine (35.3%), phosphatidylinositol (40.5%) and sphingomyelin (82.3%), respectively. The molecular distribution of fatty acids in the microsomal triglycerides and phosphatidylcholine was similar to that occurring in milk, i.e., the short chain and unsaturated fatty acids were concentrated in the primary positions (sn1 andsn3) of the triglycerides, and the unsaturated acids were preferentially located in positionsn2 of the phosphatidylcholine. The compositional data indicate that mammary microsomes are not the direct source of the phospholipids of the milk fat globule.     

Mitochondrial membrane composition of two arctic marine bivalve mollusks, Serripes groenlandicus and Mya truncata

The phospholipid and fatty acid composition of gill mitochondria membranes from two Arctic marine bivalve mollusks, Mya truncata and Serripes groenlandicus, were examined. These animals were collected from the Arctic Ocean, where waters remain below 0°C throughout the year. In both species, the primary membrane phospholipids were phosphatidylcholine, and phosphatidylethanolamine. Although a low ratio of bilayer-stabilizing phospholipids to bilayer-destabilizing phospholipids is frequently associated with cold acclimation in temperate species, this ratio is very different between the two species. The monounsaturated fatty acid 20∶1 was abundant in the membranes of both Arctic species equaling 13.0% of the fatty acid composition in S. groenlandicus, and 17.7% in M. truncata. Polyunsaturated fatty acids were relatively low in the Arctic species, equaling 35.9% of total membrane fatty acids compared to that of temperate zone mollusks. It is suggested that monoenes are common in the tissues of Arctic species since they play a role in maintaining membrane function at subzero temperatures.     

Evidence for diplasmalogen as the major component of rabbit sperm phosphatidylethanolamine

The question of whether diplasmalogens [1,2-di(O-1′-alkenyl) phosphatidyl derivatives] make up part of the plasmalogen component of cell phospholipids was examined using rabbit epididymal spermatozoa. These cells are readily obtained as a highly homogeneous suspension and long have been known to have high plasmalogen content. Phospholipids were determined by thin layer chromatography (TLC) with CuSO₄ staining. Plasmalogens were determined by hydrolysis of the phospholipids with TCA/HCl, followed by TLC and CuSO₄ staining. Ethanolamine derivatives were determined by ninhydrin. The phosphatidylethanolamine (PE) content of these cells was 29±2 μg/10⁸ cells, 90% of which was assayed as diplasmalogen and 10% as diacyl PE. No monoplasmalogen could be detected. The presence of diplasmalogen as the major component of PE was given further support from infrared and proton nuclear magnetic resonance (¹H-NMR) spectroscopy, which showed the presence of O-1′-alkenyl substituents but near absence of O-acyl substituents. The phosphatidylcholine (PC) content of the cells was 104±5 μ/10⁸ cells, of which 50% was monoplasmalogen with the 1′-alkenyl group on the 2 position of the glycerol moiety. No diplasmalogen was found in PC. The other phospholipids in rabbit sperm were phosphatidylglycerol (PG), cardiolipin (CL), sphingomyelin (SP) and lysophosphatidylcholine (LPC). Phosphatidylserine (PS) and phosphatidylinositol (PI) were present at the limits of detectability of the TLC method. None of these phospholipids contained plasmalogen. The PE component of rabbit sperm phospholipids appears to differ from that of the other cells in having the previously unreported diplasmalogen as its major constituent.     

Lipid composition of perilla seed

The composition of lipids and oil characteristics from perilla [Perilla frutescens (L.) Britt.] seed cultivars are reported. Total lipid contents of the five perilla seed cultivars ranged from 38.6 to 47.8% on a dry weight basis. The lipids consisted of 91.2–93.9% neutral lipids, 3.9–5.8% glycolipids and 2.0–3.0% phospholipids. Neutral lipids consisted mostly of triacylglycerols (88.1–91.0%) and small amounts of sterol esters, hydrocarbons, free fatty acids, free sterols and partial glycerides. Among the glycolipids, esterified sterylglycoside (48.9–53.2%) and sterylglycoside (22.1–25.4%) were the most abundant, while monogalactosyldiacylglycerol and digalactosyldiacylglycerol were present as minor components. Of the phospholipids, phosphatidylethanolamine (50.4–57.1%) and phosphatidylcholines (17.6–20.6%) were the major components, and phosphatidic acid, lysophosphatidylcholine, phosphatidylserine and phosphatidylinositol were present in small quantities. The major fatty acids of the perilla oil were linolenic (61.1–64.0%), linoleic (14.3–17.0%) and oleic acids (13.2–14.9%). Some of the physicochemical characteristics and the tocopherol composition of perilla oil were determined.     

Analyses of lipids and fatty acids in ripe roes of some Northwest European marine fish

Lipid class analyses and fatty acid analyses of neutral and polar lipids were carried out on ripe roes of herring, cod, haddock, whiting, saithe, sand eel and capelin. Total lipid was 10–26% of roe dry weight. The species with the highest total lipid, sand eel and capelin, also had the highest percentage of neutral lipid in total lipid, 77% and 49% respectively. In the other species, phospholipids accounted for 62–77% of roe total lipid. Both the neutral lipids, and especially the phospholipids, of all species were very unsaturated because of high concentrations of (n−3) polyunsaturated fatty acids (PUFA), frequently amounting to 50% of the total egg lipid. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) had similar fatty acid compositions in all species, with an average ratio (n−3)/(n−6) of ca. 20∶1. Phosphatidylinositol (PI) consistently had high concentrations of 18∶0 and 20∶4 (n−6) with an average ratio of (n−3)/(n−6) of 1.8∶1. Requirements for high levels of (n−3) PUFA in the embryonic and early larval development stages of marine fish are suggested as is a special role for the 20∶4(n−6) in PI.     

Phospholipids inDrosophila heads: Effects of visual mutants and phototransduction manipulations

A procedure was developed to label phospholipids inDrosophila heads by feeding radioactive phosphate (³²P_i). High-performance thin-layer chromatography showed label incorporation into various phospholipids. After 24 h of feeding, major phospholipids labeled were phosphatidylethanolamine (PE), 47%; phosphatidylcholine (PC), 24%; and phosphatidylinositol (PI), 12%.Drosophila heads have virtually no sphingomyelin as compared with mammalian tissues. Notable label was in ethanolamine plasmalogen, lysophosphatidylethanolamine, lysophosphatidylcholine and lysophosphatidylinositol. Less than 1% of the total label was in phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. Other lipids labeled included phosphatidylserine, phosphatidic acid and some unidentified lipids. A time course (3–36 h) study revealed a gradual decrease in proportion of labeled PI, an increase in proportion of labeled PC and no obvious change in labeled PE. There were no significant differences in phospholipid labeling comparing theno receptorpotential (norpA) visual mutant and wild type under lightvs. dark conditions. However, overall³²P labeling was higher in the wild type fed in the light as compared to the dark and tonorpA either in light or dark. This suggests that functional vision facilitates incorporation of label. Differences in phospholipid labeling were observed between young and aged flies, particularly in lysophospholipids and poly-PI, implicating phospholipase A₂ function in recycling. Manipulations such as theouterrhabdomeresabsent andeyesabsent mutants and carotenoid deprivation failed to yield notable differences in phospholipid labeling pattern, suggesting that phospholipids important to vision may constitute only a minor portion of the total labeled pool in the head.     

A comparative study of the lipids of chylomicron membrane and fat core and of the lymph serum of dogs

Thoracic lymph was collected from 13 dogs fed corn oil and butterfat. The chylomicrons were isolated by centrifugation. The lipid composition of the fat core and the membrane of the chylomicron was compared to that of the surrounding lymph serum. The fat cores contained 90–96% triglyceride, 0.7–1.9% free cholesterol, 0.2–0.5% steryl ester, 0.9–3.5% free fatty acid and 1.4–6.1% diglyceride, but no phospholipid. The lipids of the membranes contained 58–75% phospholipid, 20–35% triglyceride, 2–5% free cholesterol, 1–2% free fatty acid, and 2–3% diglyceride, but little or no steryl ester. The membrane phospholipids were made up of 70–90% lecithin, 5–20% phosphatidyl ethanolamine, and 1–3% each of lysolecithin and sphingomyelin. The lymph serum contained 24–47% of total lipid as phospholipid, of which 70–92% was lecithin; the phosphatidyl ethanolamine, lysolecithin and sphingomyelin also present contributed 1–10% each. The neutral lipids of the lymph serum contained 49–75% triglyceride, 2–15% free cholesterol, 6–23% esterified cholesterol, 10–33% free fatty acid and 1–6% diglyceride. Alterations in dietary fat, or plant sterol supplementation led to lesser changes in the lipids of the chylomicron membranes than in the lipids of any other lymph fraction. The least variation was seen in the phospholipids. Taken in part from a PhD Thesis submitted by T. C. Huang to Queen's University, Kingston, Canada, in April 1965. Presented at the AOCS 56th Spring Meeting, Houston, May 1965.     

Lipid composition of rice (Oryza sativa L.) bran

The composition of lipids of bran from three varieties of rice is reported. Lipids extracted amounted to 21.9–23.0% of the bran dry weight and consisted of 88.1–89.2% neutral lipids, 6.3–7.0% glycolipids and 4.5–4.9% phospholipids. Neutral lipids consisted mostly of triacylglycerols (83.0–85.5%), monoacylglycerols (5.9–6.8%) and small amounts of diacylglycerols, sterols and free fatty acids. Three glycolipids and eight phospholipids were separated and characterized. Acylated steryl glucoside and digalactosyldiacylglycerol were the main glycolipids, while monogalactosylmonoacylglycerol was present in small amounts. The major phospholipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol and phosphatidic acid. Phosphatidylglycerol, lysophosphatidylcholine, lysophosphatidylethanolamine and acyl-phosphatidylethanolamine were present in small quantities.     

Thermophilic fungi: III. The lipids ofHumicola grisea var.thermoidea

The lipids of the thermophilic fungusHumicola grisea var.thermoidea were qualitatively and quantitatively determined. The polar lipids consisted of 38.4–42.3% of the total lipids. The relative per cent phospholipids based upon the total phospholipids were as follows: phosphatidyl choline, 32.3–33.7%; phosphatidic acid, 24.5–31.7%; phosphatidyl ethanolamine, 15.8–20.9%; phosphatidyl inositol, 12.5–13.0%; phosphatidyl serine, 2.3–5.4%; and diphosphatidyl glycerol, 3.9–4.0%. The relatively high concentration of phosphatidic acid may be characteristic of fungi grown at elevated temperatures. Several sterol glycosides (3.1–6.0%) were present in the polar lipids. The neutral lipids consist of triglycerides, 28.6–36.0%; free fatty acids, 5.3–13.5%; sterols, 11.4–13.9%; sterol esters, 1.8–3.0%; and diglycerides, 2.2–3.4%. The sterols and derivatives comprise an unusually large fraction of the total lipids (16.3–22.9%) suggesting a role in thermostability.     

Phospholipid molecular species composition of developing fetal guinea pig brain

Adequate accumulation of polyunsaturated essential fatty acids, in particular docosahexaenoic acid (22∶6n−3), into membrane phospholipids is critical for optimal fetal brain development. This process is maximal during the period of rapid neurite outgrowth, neuritogenesis, which precedes the major growth phase, myelination. There is no information about differential changes during gestation to individual brain phospholipid molecular species which contain 22∶6n−3. Such details of brain development would be concealed by total fatty acid analysis of isolated phospholipid classes. We have detailed phosphatidylcholine (PC) and phosphatidylethanolamine (PE) molecular species compositions in developing fetal guinea pig brain. Total brain PC concentration increased substantially between 40 and 68 (term) d of gestation, corresponding to myelination, while PE increased in a biphasic manner between 25–35 d, which was coincident with onset of neuritogenesis, and 40–68 d. Fetal brain development was accompanied by complex changes in the concentration of individual phospholipid molecular species. During early gestation (25–40 d) 22∶6n−3 was enriched in both PC and PEsn−1 16∶0 molecular species. However, between 40 d and term there was no further increase in brain PC 22∶6n−3 content, while brain PE was significantly enriched in both PE 18∶1/22∶6 and PE18∶0/22∶6. We hypothesize that accumulation of 22∶6n−3 intosn−1 18∶1 and 18∶0 species represents establishment of a 22∶6n−3-containing membrane PE pool which may be turned over more slowly thansn−1 16∶0 species. Identification of specific changes in membrane phospholipids which are associated with defined events in brain development may provide a basis for assigning functional roles to individual molecular species.     

Phospholipid composition of the granular amebocyte from the horseshoe crab, Limulus polyphemus

The phospholipid composition was determined for the amebocyte of the primitive arthropod Limulus polyphemus. The total fatty acid composition of the cells' lipids was analyzed by gas chromatography/mass spectrometry (GC/MS) of fatty acid methyl esters (FAME). The FAME analysis revealed high levels of 20-carbon polyunsaturated fatty acids (PUFA), especially arachidonic (20∶4n-6) and eicosapentaenoic (20∶5n-3) acids. Almost 20% of the total lipid profile was comprised of dimethyl acetals of 16- to 20-carbon chain lengths, indicative of plasmalogens in the phospholipid pool. Phospholipids, analyzed by high-pressure liquid chromatography, included phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylinositol (PI), sphingomyelin (SPH), and cardiolipin (CL). PE and PC levels predominated at 42.2 and 36.3%, respectively. Smaller amounts of PS (9.0%) and PI (6.2%) were present, as well as low levels of SPH (4.6%), CL (1.6%), and trace amounts of lysophosphatidylcholine. The major phospholipid species, PE, PC, PS and PI, were collected and their molecular species were examined by electrospray-ionization mass spectrometry. The molecular species within the phospholipid classes reflected the high levels of PUFA seen in the total lipid profile. PI was mainly composed of 18∶0a/20∶4. Over half of the PS consisted of 18∶0a/18∶1 and 18∶0a/20∶4. The major PE species were 20∶1p/20∶5, 20∶1p/20∶4, 18∶0p/20∶5, and 18∶0p/20∶4. PC had the largest distribution of molecular species, and its most abundant species were 16∶0e/20∶5, 16∶0e/20∶4, and 16∶0p/20∶4. The presence of 16∶0e/20∶4 is the first documentation of a specific precursor to platelet-activating factor in an invertebrate hemocyte. Note: at the sn-1 position: [a=1=O-acyl, e=1-O-alkylether, and p=1-O-alk-1′-enyl (plasmalogen)].     

Fatty acid composition of subcellular particles from sheep platelets and topological distribution of phosphatidylethanolamine fatty acids in the plasma membrane

The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total lipid extracts were oleic (18∶1; 32–41%), linoleic (18∶2, 10–17%), stearic (18∶0; 13–15%), palmitic (16∶0; 11–15%) and arachidonic (20∶4; 8–12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern. Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22∶0), 18∶0 and 16∶0 acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18∶1n−9. Our findings suggest that fatty acids are asymmetrically distributed between thecholineversus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzenesulfonic acid (TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from the inner monolayer contained higher amounts of 18∶2 and significantly less 18∶1 and 20∶5 than those found in the outer monolayer, although no major differences were detected in the transbilayer distribution of total unsaturatedversus saturated PE acyl chains.     

Phospholipid molecular species from human placenta lipids

The phospholipid molecular species from a large-scale preparation of human placenta lipids were analyzed. The major placental phospholipids were choline glycerophospholipids (CPL) (53.2 wt%), sphingomyelin (21.7 wt%) and ethanolamine glycerophospholipids (EPL) (14.6 wt%). 1,2-Diacyl-glycerophosphocholine was the most abundant subclass of CPL (91.7 mol%), while EPL contained 1,2-diacyl (54.6 mol%) and 1-alk-1′-enyl-2-acyl (43.8 mol%) subclasses. The level of polyunsaturated fatty acids (PUFA) in total phospholipids was remarkably constant (38.4–39.9 mol%) within all placental batches tested. The long-chain PUFA, mainly 20∶4n−6 and 22∶6n−3 of the n−6 and n−3 series, respectively, were found in high proportion in all phospholipid classes, especially in EPL (46.7 mol%) and in inositol glycerophospholipids (IPL) (39.9 mol%). CPL and serine glycerophospholipids were much richer in 18∶1n−9 and 18∶2n−6. High levels of molecular species with arachidonic acid in thesn-2 position were found particularly in 1-alk-1′-enyl-2-acyl-glycerophospho-ethanolamine (with 24.0 mol% 16∶0 and 22.0 mol% 18∶0 insn-1 position) and in 1,2-diacyl glycerophosphoinositol with 42.6 mol% 18∶0 insn-1 position. EPL subclasses were rich in 22∶6n−3, which occurs mainly as 16∶0/22∶6n−3 (11.7 mol%) in the polasmalogen form and as 18∶0/22∶6n−3, 16∶0/22∶6n−3 and 18∶1/22∶6n−3 in the diacyl forms. Based on their availability and composition, placental phospholipids could be of interest, for example, for supplementing artificial milk preparations with n−3 and n−6 long-chain PUFA for newborn infants with insufficiently developed 18∶2n−6 and 18∶3n−3 desaturation/elongation.     

The effect of dietary linoleic acid on the fatty acid composition of individual phospholipid and lipoxygenase products from gills and leucocytes of Atlantic salmon (Salmo salar)

Diets containing either fish oil or sunflower oil, both of which supplied the minimum required level of n−3 fatty acids, were given to Atlantic salmon (Salmo salar) postsmolts for a period of 16 weeks. In fish fed sunflower oil, the phospholipids of gills showed increased 18∶2n−6 (2–13-fold), 20∶2n−6 (4.5–12-fold) and 20∶−6 (2–8-fold). In addition, phosphatidylethanolamine had increased 20∶4n−6 (1.5-fold). Changes of a similar magnitude were observed in the phospholipids of blood leucocytes except that, in addition, 20∶4n−6 was elevated in phosphatidylserine (1.7-fold) and phosphatidylinositol (1.4-fold). Both tissues showed a general decrease in phospholipid 20∶5n−3 (up to 3-fold), which caused an increase in 20∶4n−6/20∶5n−3 ratio (1.3–6-fold). The elongation and desaturation products of 20∶4n−6, 22∶4n−6 and 22∶5n−6 were not increased as a result of feeding sunflower oil. When isolated gill cells were stimulated with the calcium ionophore A23187, 12-hydroxy-8,10,14,17-eicosapentaenoic acid (12-HEPE) was the major lipoxygenase product from salmon given fish oil. 12-HEPE was significantly reduced in salmon given sunflower oil. When stimulated with A23187, the lipoxygenase products derived from whole blood of fish given sunflower oil showed decreased levels of leukotriene B₅, 12-HEPE and 12-hydroxy-5,8,10,14-eicosatetraenoic acid.     

Triacylglycerols and Phospholipids Composition of Caper Seeds (<Emphasis Type="Italic">Capparis spinosa</Emphasis>)

The goal of this study is to evaluate for the first time the composition of triacylglycerols (TAG) using ESI-TOF-MS and phospholipids species using HPLC–ESI-TOF-MS of two Capparis spinosa seed oil populations. Results show that LOO, LOP, LLO, OOO, PLL and POO were the major molecular species of triacylglycerol detected in caper seeds; where L represents linoleic acid; O, oleic acid; and P, palmitic acid. The TAG composition was significantly different among the two C. spinosa populations. In Ghar el Melh population, LOO (15.7%) was detected as the dominant TAG molecular species, followed by LOP (13.2%), LLO (12.0%) and OOO (11.4%); while, the dominant fraction was LLO (14.2%) followed by LOO (14.1%), LOP (11.5%) and PLL (10.5%) in Chouigui samples. The major component in the phospholipids fraction was phosphatidylinositol (ca. 54–91%), followed by phosphatidylglycerol, phosphatidylethanolamine and phosphatidic acid. A variety of molecular species within each class were identified. The major component in all phospholipids species contains a C-18:1 lipid chain. C16:0/C18:2-PI (ca. 28–31%) was the most abundant PI. PG species were mainly C18:2/C18:1-PG (25–32%). The major PE was C18:1/C18:1-PE (44–75%). The major PA species was C18:1/C18:1-PA (22–24%).     

Molecular speciation of fish sperm phospholipids: Large amounts of dipolyunsaturated phosphatidylserine

The molecular species compositions of the main diacyl phosphoglyceride classes and ether-linked subclasses from sperm of three species of fish, sea bass Dicentrarchus labrax, Atlantic salmon Salmo salar and Chinook salmon Onchorhynchus tsawytscha, were determined. The phospholipids from sperm were highly unsaturated, dipolyunsaturated fatty acid (diPUFA) molecular species comprised 64.6 to 71.8% of phosphatidylserine (PS), 10.1 to 17.4% of phosphatidylethanolamine (PE), and 3.3 to 10.1% of phosphatidylcholine (PC). In sea bass sperm, di22∶6n-3 phospholipid was the predominant diPUFA molecular species, but in both salmon species 22∶5n-3/22∶6n-3 was also a major constituent of PS. Phospholipids containing 22∶6n-3 dominated in sea bass sperm with 16∶0/22∶6n-3 as a major component of PC and PE, and 18∶0/22∶6n-3 of PE and PS in addition to di22∶6n-3 in the latter two classes. In contrast, both salmon species contained much more 20∶5n-3 and less 22∶6n-3 so that saturated/20∶5n-3 and monounsaturated/20∶5n-3 molecular species were more abundant than the corresponding molecules containing 22∶6n-3. Ether-linked lipids comprised 11.3–36.3% of choline and ethanolamine phosphoglycerides in each fish species. Molecular species containing 22∶6n-3 were the major components of 1-O-alkyl-2-acyl-glycerophosphocholine, especially 16∶0a/22∶6n-3 in sea bass and 18∶1a/∶6n-3 in the two salmon species, while in 1-O-alk-1′-enyl-2-acyl-glycerophosphoethanolamine, 16∶0a/22∶6n-3 was the major component in both salmon and 18∶0a/22∶6n-3 in sea bass with 18∶1a/22∶6n-3 abundant in all three species. In Atlantic salmon 1-O-alkyl-2-acylglycerophosphoethanolamine comprised 24.6% of ethanolamine glycerophospholipids which were predominantly 16∶0a/22∶6n-3 and 18∶1a/22∶6n-3. Phosphatidylinositol from sperm was dominated by stearoyl/C₂₀ PUFA molecular species, in sea bass overwhelmingly 18∶0/20∶4n-6, while in both salmon species 18∶0/20∶4n-6 and 18∶0/20∶5n-3 were equally abundant.     

The relation of carnitine to the formation of phosphatidyl-β-methylcholine byTenebrio molitor L. Larvae

Results demonstrate thatTenebrio molitor larvae can incorporate β-methylcholine into their phospholipids and that β-methylcholine spares larval choline. Phosphatidyl-β-methylcholine is detected when larvae are reared on a diet in which choline is replaced by β-methylcholine. Results indicate that, in contrast to housefly and blowfly larvae,Tenebrio larvae do not metabolize carnitine to β-methylcholine. The same phospholipids were found with all rearing conditions. They were lecithin, sphingomyelin, phosphatidylethanolamine, phosphatidylserine and two others tentatively identified as cardiolipin and phosphatidylinositol. The ratio of lecithin to sphingomyelin and to the combined other phospholipids did not vary significantly, regardless of the rearing conditions. Larvae reared on diets lacking either choline or carnitine contained more lipid phosphorus per gram of tissue than those reared on a complete diet. The fatty acid composition of the neutral lipids was similar regardless of the rearing conditions. Oleic acid represented greater than 55% of the total fatty acids, and unsaturated fatty acids comprised 75–80% of the total. Palmitic acid was the predominant saturated fatty acid. Journal Paper No. 4533, Michigan Agricultural Experiment Station, East Lansing, Michigan.