Study of free and bound lipids ofBrassica campestris,var yellow sarson

Mature seeds ofBrassica campestris var. yellow sarson were extracted with hexane to yield free lipid. The residue then was extracted with chloroform-methanol to release bound lipid. Free and bound lipids were separated into polar and nonpolar fractions chromatographically. The nonpolar fraction of both free and bound lipid consisted mainly of triglycerides with small amounts of steryl esters, free sterols, mono- and di-glycerides, and free fatty acids. The principal components of polar bound lipid were phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, and steryl glycoside. In the free polar lipid, there was more phosphatidyl inositol and less phosphatidyl choline and phosphatidyl ethanolamine. Erucic acid content was much greater in the nonpolar fractions and in the polar free lipid than in the polar bound lipid.     

Lipid composition and endogenous respiration of pig heart mitochondria

Lipid composition and endogenous respiration of pig heart mitochondria were studied in parallel, since the level of endogenous respiration affects the oxidation of added substrates and therefore the regulation of oxidative phosphorylation; mitochondrial lipids can interfere either as substrates or as partner in the energy conservation mechanism. O₂ uptake kinetics were measured in presence of different additives: ATP, ADP, NAD⁺ and hexokinase + glucose. The lipid composition of pig heart mitochondria was determined by chromatographic and spectrophotometric methods. Total lipids were 90% phospholipids; the main phosphatides were cardiolipin, phosphatidyl choline and phosphatidyl ethanolamine; the two latter were rich in plasmalogens. The main nonpolar lipids were triglycerides and free fatty acids. The fatty acid composition of total lipids, phospholipids, free fatty acids and triglycerides was determined by gas liquid chromatography. Mitochondrial lipids were characterized by a high content of unsaturation. Part of this work is included in “Thèse de Doctorat de Spècialitè en Biochimie” de J. Comte, Lyon, June 26, 1970.     

Lipid composition of further purified bovine liver nuclear membranes

The lipid content, distribution and fatty acid composition of highly purified bovine liver nuclear membranes was determined and compared to those of microsomes prepared in parallel. Contrasted with microsomes, nuclear membranes while containing nearly the same levels of lipid had more cholesterol and total neutral lipid and less phospholipid. Phospholipid and neutral lipid patterns generally were similar for the two types of membranes. The same fatty acids, in similar proportions, were observed in respective total lipid, total polar lipid, phosphatidyl choline and phosphatidyl ethanolamine fractions of the two membrane types. The microsomal lipid fractions contained slightly greater percentages of unsaturated fatty acids. With respect to previous results from preparations contaminated with nonmenbranous nuclear material, purified fractions contained more total lipid on a protein basis and more total unsaturated fatty acids. Only minor differences in levels and distribution of phospholipids and neutral lipids were observed between the crude and highly purified fractions. Purdue University AES Journal Paper No. 4482.     

Lipid metabolism of the yellow clam,Mesodesma mactroides: I. Composition of the lipids

The lipid composition of the yellow clam,Mesodesma mactroides, that lives in the northern beaches of the Buenos Aires province of Argentina was studied. The main nonpolar lipids are triglycerides and alkoxyglycerides. Phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine are the main phospholipids. The predominant fatty acids are 16∶0, 16∶1ω7, 18∶0, 18∶1ω9, 20∶5ω3, and 22∶6ω3. The are mainly provided by the clam's food and stored in the hepatopancreas. The content of polyunsaturated acids increases in summer together with an increase in nonpolar lipids and is correlative with an increase in phytoplankton in the sea water. Sexual maturity modifies the lipid composition of gametes.     

Oxidative deterioration of flesh lipids of pacific cod(Gadus macrocephalus)

Light flesh lipids of Pacific cod, composed chiefly of phosphatidyl ethanolamine and phosphatidyl choline, contain fatty acids rich in unsaturation. In model systems free of pro-oxidant the ethanolamine derivative exhibited a high rate of oxidation. Phosphatidyl choline, on the other hand, required an added pro-oxidant. Cod porphyrins exhibited pro-oxidant effects not unlike those observed in other biological systems involving catalyzed lipid oxidation. Neutral lipids exhibited very low rates of oxidation.     

Phospholipid Composition of <Emphasis Type="Italic">Jatropha curcus</Emphasis> Seed Lipids

Jatropha curcus L. oil has emerged as one of the most important raw materials for biodiesel production. However, no detailed study has been reported on characterizing the lipid constituents of jatropha oil. The present study revealed that the total oil content of jatropha seeds was 32% with a composition of 97.6% neutral lipids, 0.95% glycolipids and 1.45% phospholipids. The fatty acid composition of total lipids, neutral lipids, phospholipids and glycolipids was also determined and found to contain oleic acid (18:1) and linoleic acids (18:2) as major fatty acids. The phospholipids fraction was further characterized and quantified and found to contain phosphatidyl choline (PC) 60.5%, phosphatidyl inositol (PI) 24% and phosphatidyl ethanolamine (PE) 15.5%. The fatty acid composition and the positional distribution of the fatty acids of individual phospholipids were also reported.     

Lipid synthesis in cultured human embryonic fibroblasts

We describe here the pathways by which human embryonic fibroblasts synthesize lipids. In these studies, we quantitated the phospholipids by their phosphorus content and by their acyl components. These determinations defined both the chemical composition of the cellular membranes as well as their metabolic turnover. Using radiolabeled precursors, we have shown (a) synthesis of the glycerol moiety via glycolysis and the action of glycerokinase, (b) utilization of both exogenously added and endogenously synthesized fatty acids, (c) synthesis de novo of phosphatidyl choline and phosphatidyl ethanolamine from their base precursors, and (d) the methylation of phosphatidyl ethanolamine yielding phosphatidyl choline. Dividing cells synthesized phosphoglyceride more rapidly than cells in the stationary phase. However, considerable turnover of cellular lipid did occur in the stationary phase.     

Phospholipids of human serum

Phospholipids extracted from normal human serum were fractionated into lecithin, lysolecithin, sphingomyelin, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, phosphatidyl serine, and phosphatidyl inositol. Identification of each was established by thin-layer chromatography and infrared spectrophotometry. The content of plasmalogen was determined in both lecithin and phosphatidyl ethanolamine fractions. The composition of fatty acids and fatty aldehydes in isolated phospholipids is presented. The degree of unsaturation as reflected in the average content of double bonds per molecule of the fatty acids in phospholipids was: lecithin 1.2, choline plasmalogen 2.1, lysolecithin 0.6, sphingomyelin 0.2, phosphatidyl ethanolamine 2.8, lysophosphatidyl ethanolamine 1.0, phosphatidyl serine 1.0, and phosphatidyl inositol 1.8. Both chlline and ethanolamine plasmalogen aldehydes were predominantly saturated. Molecular weight of each phospholipid was calculated from determined fatty acid and fatty aldehyde compositions; the phosphorus factor for each phospholipid was computed. On a weight percent basis, lecithin, sphingomyelin, and lysolecithin accounted for 95% of the total phospholipids. The ethanolamine-containing phospholipids accounted for 2.5%, and the remainder was divided among phosphatidyl inositol, choline plasmalogen and phosphatidyl serine. Presented in part at the AOCS Meeting, Houston, April, 1965. Dept. of Health, Education and Welfare, USPHS.     

Distribution of cholesteryl esters and other lipid in subcellular fractions of the adrenal gland of the pig

Total lipids from whole pig adrenal glands as well as from their mitochondria, microsomes, liposomes, and cell sap were extracted and fractionated first into neutral lipids and phospholipids. The highest percentage of neutral lipids was found in the cell sap, and the lowest in the microsomal fraction. Neutral lipids were subfractionated into cholesteryl esters, free cholesterol, triglycerides, and free fatty acids. Cholesteryl esters were distributed throughout the liposomes. Free fatty acids represented a substantial part of cell sap lipids, but were present also in the mitochondria, microsomes, and liposomes. Fatty acids of all fractions were analyzed by gas liquid chromatography. Free fatty acids and cholesteryl ester fatty acids from all cellular fractions were similar in composition and were characterized by considerable quantities of linoleic and arachidonic acid. Triglycerides were characterized by an increased percentage of palmitic and a low content of arachidonic acid. Phosphatidyl choline, phosphatidyl ethanolamine, diphosphatidyl glycerol, and sphingomyelin plus phosphatidyl inositol were isolated from the lipids by preparative thin layer chromatography, and their fatty acids analyzed by gas liquid chromatography. Phosphatidyl choline and phosphatidyl ethanolamine from mitochondria, microsomes, and cell sap were very similar in respect of their fatty acid composition. Sphingomyelin plus phosphatidyl inositol was characterized by a high content of C22:2omega6. Diphosphatidyl glycerol was present in mitochondria and in the cell sap.     

Lipid metabolism ofAgaricus bisporus (Lange) sing.: I. Analysis of sporophore and mycelial lipids

The lipid components of four strains ofAgricus bisporus (Lange) Sing., the cultivated mushroom, were analyzed. Both sporophore and mycelial samples were obtained from beds in normal production. A method for obtaining mycelium free of compost was developed. Neutral lipids were separated from polar lipids by silicic acid column chromatography. Each fraction was separated by thin layer chromatography. Fatty acid methyl esters were analyzed by gas liquid chromatography and mass spectrometry. Sporophore extracts contained free sterol, free fatty acid, triglycerides, phosphatidyl choline and phosphatidyl ethanolamine. High amounts of linoleic acid were found in both neutral and polar lipid fractions. Mycelial extracts contained free fatty acids, triglycerides, phosphatidylcholine and phosphatidyl ethanolamine. No free sterol could be detected. Linoleic acid was also present in large amounts. Paper 3798 in the Journal Series of The Pennsylvania Agricultural Experiment Station.     

Phospholipid composition of the boll weevil,Anthonomus grandis boheman

When phospholipids of newly-emerged adults of the boll weevil,Anthonomus grandis Boheman, were studied in detail, phosphatidyl choline and phosphatidyl ethanolamine were found to be the major phospholipids; sphingomyelin and cardiolipin were present in smaller amounts, and four other minor components were identified. Fatty acid analyses performed on the intact phospholipids and on the enzyme degradation products of phosphatidyl choline and phosphatidyl ethanolamine demonstrated that oleic and linoleic acids were the major fatty acids present in the glycerophosphatides; the sphingomyelin contained fatty acids in the range of 20–22 carbons.     

Lipid labeling with32P-orthophosphate and14C-acetate in marine copepods

Freshly collectedCalanus pacificus were maintained in sea water containing 25 μCi/ml [³²P]orthophosphate or 1 μCi/ml [¹⁴C]acetate at 10 C for 24 hr. The animals took up label from the environment and incorporated it into various lipid fractions. After incubation with [¹⁴C]acetate the order of specific activity of the different lipid classes was: phospholipids > free fatty acids > wax esters > triglycerides. Argentation thin layer chromatography of the fatty acid methyl esters showed that ca. 50% of the activity was in saturated fatty acids and 34% in polyunsaturated acids. When the animals were exposed to [³²P]orthophosphate, lysophosphatidyl choline became most heavily labeled, followed by lysophosphatidyl ethanolamine, sphingomyelin, phosphatidyl ethanolamine, and phosphatidyl choline. Comparison of the data obtained with those available for decapods and mammals revealed striking similarities between these phylogenetically distant groups. It is believed that labeling the lipids of marine and freshwater planktonic crustaceans in this way will provide much information about the metabolism of lipids in these organisms.     

Lipid Composition of Garlic

Neutral, glyco- and phospholipids of garlic were resolved into their component fractions by thin layer chromatography. Neutral lipids contained considerable quantities of monoglycerides (18.5%), diglycerides (14.2%), sterols (16.3%) and triglycerides (41.5%) respectively. The phospholipid fraction was rich in phosphatidyl choline (23.5%), phosphatidyl ethanolamine (17.9%), lysophosphatidyl choline (11.8%) and lysophosphatidyl ethanolamine (8.2%). Digalactosyl diglyceride (10.1%), sterol glycoside (15.6%), cerebrosides (8.1%), acylsterol glycoside (38.6%) and monogalactosyl diglyceride (22.5%) were the major components of the glycolipids of garlic. Lauric, myristic, palmitic and linoleic acids constituted the major fatty acids of monoglycerides, diglycerides and free fatty acid fractions whereas palmitic, linoleic and linolenic acids were the major fatty acids of triglycerides. Palmitic and linoleic acids were the major fatty acids of garlic phospholipids. Except the acylsterol glycoside fraction glycolipids were rich in lauric, palmitic, linoleic and linolenic acids; palmitic acid was the only major fatty acid of acylsterol glycosides.     

The lipid components of white potato tubers (Solanum tuberosum)

Four Canadian varieties of potatoes were examined for their lipid composition. Lipids, extracted with chloroformmethanol, were shown by TLC and column chromatography to consist of 16.5% neutral lipids, 45.5% phospholipids and 38.1% glycolipids. Among the phospholipids and glycolipids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, the galactolipids and the sterol glucosides were the major lipids. The predominant fatty acids were palmitic (19.5%), linoleic (44.8%) and linolenic (30.4%, in Kennebec). Analyses of the fatty acids of stored potatoes showed a marked decrease in linoleic acid and an increase in linolenic acid, in the Irish Cobbler and Sebago potatoes. β-sitosterol comprised 85.0% of total sterols. Nearly half of the carotenoids was lutein (xanthophyll), the others being α-carotene, β-carotene, an unidentified pigment and lutein epoxide. Contribution No. 101 of the Food Research Institute, Canada Department of Agriculture.     

On the phospholipids ofCulex pipiens fatigans

The lipids of different developmental stages ofCulex pipiens fatigans, vector of bancroftian filariasis, have been investigated. The phospholipid composition of the developmental stages and of the subcellular fractions of fourth instar larvae of the insects were analyzed. The composition of fatty acids and their positional distribution have also been examined in the major phospholipids of the larvae. The insect eggs contained higher amounts of lipids than larvae suggesting that they were utilized during embryogenesis. Phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) comprised over 75% of the insect phospholipids. Of these, PE was present in the greatest amounts during all stages of growth and in the subcellular fractions of larvae. An ethanolamine containing sphingolipid was found as a component of the phospholipids of the insects. About 50% of the lipids of the larvae were localized in the cell debris and nuclei fraction which also contained most of the lysolipids of the insects. As in other Diptera 16∶0, 16∶1 and 18∶1 were the major fatty acids present in the insect lipids of which the fatty acid found in greatest amounts was 16∶1. Similar to the phospholipids of animal species, saturated fatty acids were predominantly linked to the 1 position of the major phospholipids of the insects while the unsaturated fatty acids were in higher amounts at the 2 position.     

Lipid Studies of Pimpinella acuminata

The seed oil of Pimpinella acuminata species of the family Umbelli-ferae was extracted with chloroform : methanol (2:1) for the separation of different classes of lipids as hydrocarbons (1.7%), sterol esters (traces), triglycerides (74.1%), free fatty acids (6.6%), 1,3-diglycerides (1.6%), 1,2-diglycerides (1.6%), sterols (1.8%), mono-glycerides (2.0%), phosphatidyl ethanolamine (0.8%), phosphatidyl choline (1.2 %), lyso phosphatidyl ethanolamine (0.4%), phosphatidyl inositol (1.2%) and unknown (7.0%). The fatty acids as determined by application of gas liquid chromatography is C₁₀-C₂₂, whereas C_16:0, C_18:0-C_18:2 and C_18:2 are predominantly present in all polar and non-polar lipid classes.     

Influence of microwave roasting on positional distribution of fatty acids of triacylglycerols and phospholipids in sunflower seeds (Helianthus annuus L.)

Whole sunflower seeds were exposed to microwave roasting for 6, 12, 20 or 30 min at a frequency of 2450 MHz. The kernels were then separated from the sunflower seeds, and the lipid components and the positional distribution of fatty acids in triacylglycerols (TAGs) and phospholipids (PLs) were investigated. Major lipid components were TAGs and PLs, while steryl esters, free fatty acids and diacylglycerols were also present in minor proportions. The greatest PL losses (p < 0.05) were observed in phosphatidyl ethanolamine, followed by phosphatidyl choline or phosphatidyl inositol. Significant differences (p < 0.05) in fatty acid distributions occurred (with few exceptions) when sunflower seeds were microwaved for 20 min or more. Nevertheless, the principal characteristics for the positional distribution of fatty acids still remained after 20 min of microwave roasting; unsaturated fatty acids, especially linoleic, were predominantly concentrated in the sn‐2‐position and saturated fatty acids, especially stearic and palmitic acids, primarily occupied the sn‐1‐ or sn‐3‐position. These results indicate that no significant changes in fatty acid distribution of TAGs and PLs would occur within 12 min of microwave roasting, ensuring that a good‐quality product would be attained.     

Lipid composition of yoshida ascites hepatoma and of livers and blood plasma from host and normal rats

The lipid composition of Yoshida ascites hepatoma cells was analyzed together with that of ascitic plasma and of livers and blood plasma from host and normal rats. In comparison to normal livers, host livers showed no significant differences in the content of the various lipid classes, but contained a higher percentage of palmitic acid and a lower proportion of arachidonic acid in the major phospholipid classes. In addition, tumor growth induced a marked hypertriglyceridemia in host animals; changes in the concentration of other plasma lipid classes were not statistically significant. The ascitic plasma contained small amounts of lipids mainly constituted by cholesteryl esters and phospholipids. Yoshida hepatoma cells contained less phospholipids in comparison to both host and normal liver, while the increased level of triglycerides and the decrease of free fatty acids were not statistically significant. Hepatoma cells showed appreciable amounts of ether-linked lipids associated in part to neutral lipids (as glyceryl ether diesters) and, in part, to ethanolamine and choline phosphoglycerides. The alkyl groups in GEDE as well as in ethanolamine and choline phosphoglycerides were mainly constituted by C_16∶0 and C_18∶0 followed by C_18∶1. The alk-1-enyl groups in ethanolamine and choline phosphoglycerides were C_16∶0 and C_18∶0 with only a minor proportion of C_18∶1. In comparison to both host and normal liver, Yoshida hepatoma cells showed significant changes in the fatty acid composition of neutral lipids and phospholipids. Some of the major changes consisted of an increase of monoenoic acids associated with a decrease of arachidonic and docosahexaenoic acids in phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol.     

Biochemical Studies on Whey Lipid Substances

The present work was undertaken to determine the lipid materials of salted and unsalted whey as a byproduct of cheese industry. The general chemical analysis show that the salted whey contained lower amounts of lactase, proteins and lipids compared with unsalted whey. Whey lipids contained palmitic and oleic acids as the most abundant saturated and unsaturated acids, respectively. The presence of salt quantitatively altered the concentration of short-chain fatty acids due to its salting out phenomenon. A wide variety of hydrocarbons was found and C₂₂, C₂₃ constituted over 75% of the total hydrocarbons. The presence of salt in whey remarkably changed the hydrocarbon profile. The most predominant phospholipid was phosphatidyl choline followed by phosphatidyl inositol. Once more, the salt changed qualitatively and quantitatively the whey phospholipid pattern and led to precipitate some of the highly polar phospholipids with cheese during milk processing.     

Phospholipid oxidation in emulsions

The autoxidation of purified phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC), extracted from egg and soybean lipids, was followed by oxygen uptake measurements in emulsified systems. All emulsified phospholipid fractions had comparable activation energies. Measurement by various physico-chemical tests was made of specific changes in the phospholipid molecule during autoxidation. PE oxidized more rapidly and absorbed more oxygen than PC. Higher 2-thiobarbituric acid test and diene and triene conjugation absorbance values were observed for PE than for PC. Of the two major polyunsaturated fatty acids in egg phospholipids, arachidonic acid disappeared at a more rapid rate during oxidation while the concentration of linoleic acid decreased to a level that was relatively constant. Although typical unsaturated fatty acid oxidation appeared to occur in all phospholipid fractions, oxidation in aqueous emulsions was only partly a function of fatty acid composition. The nitrogen moieties, ethanolamine and choline influenced the induction period for the oxidation of PE and PC respectively. Michigan Agriculture Experiment Station Journal Article No. 4420. Presented in part at the AOCS Meeting, Chicago, October 1967.