Lipid and sterol composition of the pollen of the west african oilpalm, Elaeis guineensis

The lipid classes, fatty acid methyl esters and the sterols of oilpalm pollen were analysed. The neutral lipid fraction consisted of triglycerides, esterified and free sterols and trace amounts of hydrocarbons. Monogalactosyl and digalactosyl diglycerides, phosphatidyl choline, phosphatidyl inositol and phosphatidyl ethanolamine represented the polar lipids. The major fatty acids were linoleic, palmitic and linolenic acids together with small to trace amounts of oleic, stearic, arachidic, myristic, lauric, palmitoleic and margaric acids. Unsaturated fatty acids predominated over saturated ones in the ratio of 3:2. The 4-desmethyl sterols were the major phytosterols in the free form but they constituted a lower proportion of the sterols in the esterified state. 28-Isofucosterol was isolated and characterized as the principal sterol.     

Lipid compositions of cells isolated from pig, human, and rat epidermis.

Epidermal slices from pig, human, and rat skin were treated with dilute buffered trypsin solution (0.005%, w/v), and suspensions of mixed basal and spinous cells were obtained in good yield. Total lipids accounted for approximately 8% of the pig, 10% of the human, and 20% of the rat epidermal cell (dry weight). Phospholipids in pig, human, and rat cells accounted for, respectively, 62%, 53%, and 35% of the total lipids. Phosphatidylcholine (34-38%), phosphatidylethanolamine (18-23%), and sphingomyelin (17-21%) were major compounds in all species. The major neutral lipids were sterols (mostly cholesterol) and triglycerides. Free fatty acids were a major lipid class in pig and human cells, whereas wax esters were a major component in rat epidermal cells. Nearly half (45%) of the sterols in rat cells but less than 10% of those in pig and human cells were esterified. Cholest-7-ene-3beta-ol accounted for 20% of the total sterols in rat cells. Cholesteryl sulfate and ceramide were minor lipids in the three species. The predominant glycosphingolipid (greater than 99%) was glucosylceramide, which accounted for 7% and 9%, respectively, of the total lipids in pig and human cells. A significant proportion (pig, 17%; human, 11%) of the fatty acids in the glucosylceramides were C26:0 and C28:0.     

Occurrence of steryl and wax esters in Dicranum elongatum

The steryl and wax esters of the frozen subarctic moss Dicranum elongatum Schleich contained fatty acids 39.8 mg per gram dry green tissue. The content decreased with increasing age of the moss shoots, but no great changes were found in the fatty acid pattern of the esters. The major part of the steryl and wax ester fraction of the green shoots was made up of esterified sterols (85%), and the rest (15%) of esterified aliphatic alcohols. No great changes were found in their relative proportions with increased age of the shoots. Some changes were evident in the pattern of individual esterified sterols, however. The proportion of cycloartenol was lower in the older parts than in the green part, and the proportion of campesterol, stigmasterol, and β-sitosterol were lower in the green part. The major esterified aliphatic alcohols were 1-octadecanol, phytol and geranylgeraniol. The proportion of geranylgeraniol was highest in the green part and that of phytol in the older parts. The main alcohol of the surface lipids was 1-octadecanol.     

Dimorphism-associated variations in the lipid composition of Candida albicans

Yeast and mycelial forms of Candida albicans ATCC 10231, growing together in 12 h and in 96 h cultures, were separated and their lipids were extracted and characterized. The total lipid content of the yeast forms was always lower than that of the mycelial forms. In 12 h cultures the lipids from the two morphological forms consisted mainly of polar compounds, viz, phospholipids and glycolipids. In 96 h cultures both the yeast and mycelial forms accumulated substantial amounts of apolar compounds, mainly steryl esters and triacylglycerols. The mycelial forms were more active than the yeast forms in this respect. Major differences in the lipid composition between the two morphological forms involved the contents of sterols and complex lipids that contain sterols. As a rule, the yeast lipids contained much larger proportions of free sterols than the mycelial lipids. However, the mycelial lipids contained several times more sterols than the yeast forms but bound as steryl glycosides, esterified steryl glycosides and steryl esters. Steryl glycosides and esterified steryl glycosides occurred in yeast lipids only in traces, if at all. The major steryl glycoside in the mycelial forms was unequivocally identified as cholesteryl mannoside. At both phases of growth the apolar and polar lipid fractions from the mycelial forms contained higher levels of polyunsaturated fatty acids (18:2 and 18:3) but lower levels of oleic acid (18:1) than the corresponding fractions from the yeast forms. The lipid content and composition of 12 h and 96 h yeast and mycelial forms of C. albicans KCCC 14172, a clinical isolate, were almost identical with those of C. albicans ATCC 10231.     

Sterols in hardening winter wheat

The main sterols in winter wheat crowns and roots were sitosterol and campesterol, with significant amounts of stigmasterol and traces of cholesterol. The main groups of sterol-containing lipids were free sterols, steryl glucosides, steryl esters and esterified steryl glucosides. Sterol analysis within each group showed little difference between them. Steryl esters were relatively rich in cholesterol and poor in stigmasterol. Free sterols were rich in stigmasterol. Low temperature caused an increase in sterol content but had little effect on sterol composition and sterol to lipid P ratio. There was some increase in steryl esters and some decrease in free sterols. Cholesterol and stigmasterol decreased in the steryl ester and free sterol fractions, respectively. There was little evidence for involvement of sterols in winter wheat frost hardening.     

Lipids of chicken epidermis

The lipids from chicken epidermis were analyzed by a combination of quantitative thin-layer and gas-liquid chromatography and by chemical and spectroscopic methods. The lipid groups present included wax diesters (34%), triglycerides (32%), sterols (11%), phospholipids (11%), nonphosphorus-containing sphingolipids (3%), beta-D-glucosylsterols (3%), 6-O-acyl-beta-D-glucosylsterols (2%), steryl esters (1%), cholesteryl sulfate (1%), and free fatty acids (1%). The major phospholipids were phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin, and the sphingolipids included ceramides, glucosylceramides, O-acylceramides, and O-acylglucosylceramides. Glucosylsterols and acylglucosylsterols have not been found in mammalian skin, and may be relevant to the evolutionary history of the epidermal water barrier. The wax diesters contained mainly 16-, 18-, and 20-carbon saturated fatty acids esterified to 20- through 24-carbon threo and erythro 2,3-diols, while the chicken epidermal triglycerides contained some very long-chain (26-40 carbon) saturated fatty acids. These wax diesters and unusual triglycerides may be of significance in human health.     

Metabolic interconversion of free sterols and steryl esters in Saccharomyces cerevisiae.

The interconversion of free and esterified sterols was followed radioisotopically with [U-14C]acetate and [methyl-14C]methionine. In pulse-chase experiments, radioactivity first appeared mainly in unesterified sterols in exponential-phase cells. Within one generation time, the label equilibrated between the free and esterified sterol pools and subsequently accumulated in steryl esters in stationary-phase cells. When the sterol pools were prelabeled by growing cells aerobically to the stationary phase and the cells were diluted into unlabeled medium, the prelabeled steryl esters returned to the free sterol form under several conditions. (i) During aerobic growth, the prelabeled sterols decreased from 80% to 45% esters in the early exponential phase and then returned to 80% esters as the culture reached the stationary phase. (ii) Under anaerobic conditions, the percentage of prelabeled steryl esters declined continuously. When growth stopped, only 15% of the sterols remained esterified. (iii) In the presence of an inhibitor of sterol biosynthesis, which causes accumulation of a precursor to ergosterol, prelabeled sterols decreased to 40% steryl esters while the precursor was found preferentially in the esterified form. These results indicate that the bulk of the free sterol and steryl ester pools are freely interconvertible, with the steryl esters serving as a supply of free sterols. Furthermore, there is an active cellular control over what types of sterol are found in the free and esterified sterol pools.     

Lipids in plant tissue cultures IV. The characteristic patterns of lipid classes in callus cultures and suspension cultures

Lipids from callus cultures and suspension cultures of higher plants constitute 5 to 8% of the dry tissue's weight.The predominant lipid classes are the sterols, steryl esters, steryl glycosides and esterified steryl glycosides. Considerable amounts of a variety of sterylglycolipids, whose structures are not completely elucidated, are also present. Triglycerides and phospholipids occur in small proportions, whereas monogalactosyl diglycerides, digalactosyl diglycerides and sulfoquinovosyl diglycerides are present only in traces, if at all.β-Sitosterol is the predominant constituent sterol, stigmasterol and campesterol as well as a variety of as yet unidentified sterols occur in smaller proportions. The major constituent fatty acids are palmitic, oleic, linoleic and linolenic acids. Saturated very long-chain fatty acids are found in smaller proportions. Unusual fatty acids, such as epoxy acids, which occur in the seed lipids of certain plants, are not found in tissue cultures derived from these plants. Clucose and traces of galactose are the only sugars obtained by acid hydrolysis of the glycolipids occurring in plant tissue cultures.     

Lipids in plant tissue cultures. VI. Effect of temperature on the lipids of Brassica napus and Tropaeolum majus cultures

The lipid contents of callus cultures of rape (Brassica napus) and nasturtium (Tropaeolum majus) increase in response to decreasing the temperature, though to different degree. Irrespective of the incubation temperature the lipids in cultures of both plants contain as predominant classes steryl glycosides, esterified steryl glycosides, sterols, steryl esters and fatty acids and, as minor constituents, various proportions of triacylglycerols, phospholipids and several unidentified fractions.The ratio of phospholipids to triacylglycerols as well as the ratio of diacylglycerophosphorylethanolamines to dicylglycerophosphorylcholines increase with time both in rape cultures incubated at 30°C and in those kept at 5°C.The lipids in rape and nasturtium cultures grown at 30°C contain smaller proportions of polyunsaturated fatty acids than the lipids in cultures incubated at 5°C. Erucic acid, the major constituent fatty acid of the seed lipids, in both plants, occurs only in trace amounts in the lipids of callus cultures. In contrast, linoleic and linolenic acids, which occur only in traces in the seed lipids of nasturtium, are major constituent fatty acids in the lipids of callus cultures derived from seedlings of this plant.The levels of constituent polyunsaturated fatty acids in the diacylglycerophosphorylethanolamines and the diacylglycerophosphorylcholines increase with time whereas in the triacylglycerols only linolenic acid is slightly increased.     

Sterol Changes during Germination of Nicotiana tabacum Seeds

The identity, composition, and concentration of the total, free, esterified, and glycosidic sterol fractions were determined during germination of tobacco seeds. The total, free, and esterified sterols increased, with stigmasterol and campesterol accounting for most of the increase. Steryl glycosides decreased during germination, and stigmasteryl and sitosteryl glycosides showed the largest decrease. During germination, sitosterol was the major sterol in all fractions but stigmasterol and campesterol showed the greatest changes. The fatty acid composition of the steryl esters and acylated steryl glycosides most closely resembled the di- and triglycerides.     

Detailed Analyses of Individual Neutral Lipid Classes of Pneumocystis

SUMMARY Individual neutral lipid classes of Pneumocystis carinii carinii were isolated and purifed by thin-layer chromatography. The fatty acids in steryl esters, triglycerides, free fatty acids, diglycerides, and monoglycerides were quantified by gas-liquid chromatography. The fatty acid compositions of these lipids were similar to those of the neutral lipid classes in whole rat lung controls, unlike comparable studies of phospholipid classes. The free fatty alcohols of rat lung controls and P. carinii were also identified and quantified; only saturated fatty alcohols were detected.     

The Fatty Acid Composition of Paramecium aurelia Cells and Cilia: Changes with Culture Age

SYNOPSIS.
The fatty acids of whole cells and cilia from Paramecium tetraurelia strains 51s and d,95 and from Paramecium octaurelia strain 299s were identified. Ciliates were grown axenically in 3 types of culture media. More than 30 fatty acid species were identified and their structures determined by gas chromatography, mass spectrometry, argentation chromatography, hydro-genation, and fragmentation technics. The major fatty acids were hexadecanoic, octadecanoic, 9-octadecenoic, 9,12-octadecadi-enoic, 6,9,12-octadecatrienoic, and 5,8,11,14-eicosatetraenoic acids. Minor variations in fatty acid compositions were observed in cells grown in the different culture media as well as among the 3 strains. Major changes in fatty acid compositions occurred with culture age and cell density. The cells accumulated exogenous lipids in cytoplasmic vesicles. These lipids were utilized as culture age progressed. Both cellular volume and lipid content were greater in young than in older cultures. Fatty acid compositions of both whole cells and cilia changed with age and had a relative decrease in saturated, short-chained and odd-numbered carbon acids. Cilia lipids were enriched in long-chained, polyunsaturated acids as compared to lipids in whole cell extracts. Eicosatetra-enoic acid (arachidonic acid) increased to the greatest extent with age in both cellular and ciliary lipids, accounting for 20–60% of the total fatty acids in cilia. The age-related change in fatty acid composition in Paramecium is among the largest observed in eukaryotic organisms. It was concluded that some minor fatty acids found in Paramecium lipids were incorporated directly from certain culture media and that Paramecium had w 3, 6, and 9 pathways for polyunsaturated fatty acid biosynthesis.     

Composition of lipids and production of mucidin in a submerged culture of the basidiomyceteOudemansiella mucida

Mycelial lipids of the submerged culture ofOudemansiella mucida contain acylglycerols, free and esterified sterols. Free fatty acids are not present. Development of the culture is associated with an increased content of unsaturated fatty acids and, on the contrary, with a decreased content of saturated fatty acids. Content of total lipids depends on age of the culture and is inversely related with production of the antibiotic mucidin.     

The utilization of sterols and other lipids by insect cells grown in vitro

Cells derived from Antheraea eucalypti were grown in vitro in a medium containing triglycerides, diglycerides, free fatty acids, and sterols as the main ‘neutral’ lipids. The sterol content of the medium was derived chiefly from the haemolymph component. The ‘neutral’ lipids in the cells were triglycerides, free fatty acids, and sterols. During growth over 6 days there was a quantitative balance between cholesterol and β-sitosterol gained by the cells and those sterols removed from the medium when allowance was made for losses from sterile medium. Cells metabolized more triglycerides and free fatty acids than they incorporated.     

Hexane soluble non-volatiles in flowering to fruiting stages of Fatsia japonica

The n-hexane soluble non-volatile fraction of the acetone extracts from the flower buds, the flowers and the immature and the mature fruits of Fatsia japonica were all found to contain fatty acids, fatty acid methyl esters, squalene, β-amyrin and sterols. At all the stages between budding to the mature fruit, the major fatty acids were palmitic and linoleic acids and the major phytosterol was stigmasterol. In addition steryl and β-amyrenyl esters were found in the flowers and the immature and the mature fruits, but these esters were not present in the flower buds. Sitosteryl ester was the major constituent of the steryl ester fraction in the fruiting stages. Phytol was found in only the flowering stage and triglycerides in only the mature fruits. The variations in the lipid constituents is discussed in relation to the stages from budding to the mature fruit.     

Effect of light on lipid composition of Ricinus cell cultures

The changes of lipid composition were determined in callus cultures from Ricinus communis endosperm upon transfer from darkness into light. Culture in light induced chlorophyll synthesis and formation of differentiated chloroplasts. In light-grown cultures the major lipid classes were phospho- and glycolipids, dark-grown cultures were rich in triacylglycerol. The major fatty acids were linolenic acid and palmitic acid in both cultures. In the green cultures linolenic acid was predominantly esterified in glycolipids whereas in the dark-grown cultures this fatty acid was the major component of phospholipids. Ricinoleic acid was not found.Abbreviations PC phosphatidylcholine - PE phosphatidylethanolamine - MGD monogalactosyldigylceride - DGD digalactosyldiglyceride - SE steryl esters - NL neutral lipids     

Separation and analysis of steryl and wax esters from Dicranum elongatum

Abstract Complete separation of the steryl and wax esters in the subarctic moss Dicranum elongatum was achieved on MgO thin-layer plates without any notable alteration of the acyl and alkyl moieties of the esters. Gas chromatography-mass spectrometry of the hydrolyzed fraction showed that the sterols (campesterol, stigmasterol, sitosterol, cycloartenol, 24-methylene cycloartanol and an unidentified sterol) were primarily esterified with unsaturated fatty acids 18:2 ω 6, 18:3 ω 3 and 20:4 ω 6. In contrast, the wax alcohols (l-octadecanol, phytol and geranylgeraniol) were mainly esterified with saturated fatty acids with 16:0, 18:0 and 20:0 as major components. No great differences were found in the fatty acid pattern of the steryl esters between different portions of the shoot. Slight differences, however, were found in the proportions of ω 3 and ω 6 fatty acids. In the wax esters a clear decrease was found in the proportions of 18:0 and 20:0 acids with increased shoot age accompanied by a slight increase in the proportions of 14:0, 20:4 ω 6 and phytenic acid.     

Lipids of Paramecium

This review is the first on the composition and metabolism of Paramecium lipids. This ciliated protozoa is a useful system for studying the structure and function of biomembranes since it can be grown under chemically defined culture conditions in large numbers; much is known about its genetics, membrane electrophysiology, and ultrastructure; and mutants with defective membrane functions are available which are reported to have lipid alterations. Pure preparation of the cell surface ciliary membrane are readily isolated. The organism and its ciliary membrane contain a variety of polar lipids, sterols, and steryl esters. The polar lipids include substantial amounts of ether lipids, sphingolipids, and phosphonolipids. the biosyntheses of fatty acids and specific moieties of complex lipids in this organism are beginning to be examined with promises of elucidating biosynthetic mechanisms that are more difficult to study in other organisms. More information on lipid metabolism is required to identify the bases for the defects in putative lipid/membrane mutants.     

Lipids and lipolytic enzymes in the trunkwood ofRobinia pseudoacacia L. during heartwood formation

The radial distribution of membrane and storage lipids was determined in the trunkwood ofRobinia pseudoacacia L. The trees were felled in November at the time of heartwood formation and fluctuations in the amount and composition of phospholipids, free sterols, steryl esters, diand triacylglycerols, and free fatty acids were investigated across the sapwood-heartwood boundary. The individual compounds were identified and quantified by thin layer chromatography, enzymatic and colorimetric assays, and by capillary gas chromatography. Phospholipids show a significant decrease towards the boundary area, and in the heartwood only trace amounts can be detected. The same pattern is observed for free sterols in the sapwood; in the heartwood, however, they reach maximum values with increasing depth of the trunk. Steryl esters exhibit a complementary behaviour by accumulating at the periphery of the heartwood. No concentration changes are found in the total amounts of diacylglycerols and free fatty acids. In contrast, the triacylglycerol concentration declines steadily across the trunk. With regard to qualitative composition, free fatty acids and the fatty acid moieties of the esterified constituents vary in their chain length from 14 to 24 carbon atoms and have up to three double bonds. A radial gradient in the ratio saturated/unsaturated fatty acids can be observed: except for the phospholipid fraction the relative amounts of unsaturated fatty acids increase in centripetal direction. Seven phospholipids were identified: phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol, and phosphatidic acid, which constitutes the major proportion. In the sterol group, sitosterol is the most abundant component. The composition of the esterified sterols remains constant across the trunk cross-section, whereas the relative frequencies of individual free sterols change markedly.     

Lipids of Rhizopus arrhizus Fischer

The lipids of Rhizopus arrhizus Fischer mycelia and sporangiospores were extracted, isolated, and separated by thin-layer, liquid, and gas chromatography. Structural confirmations of the compounds were made by a gas chromatographmass spectrometer combination. The n-heptane fraction contained squalene (1%) as a major hydrocarbon constituent. Other major lipid classes detected were free fatty acids, naturally occurring methyl esters of fatty acids, triglycerides, sterols, and polar lipids. The polar lipids (44.4%) were found in the highest concentrations, and the triglycerides (22.1%), sterols (16.7%), and free fatty acids (11.7%) were present in lesser concentrations. This is the first report of naturally occuring methyl esters of long-chain fatty acids being present in fungal mycelium. There appears to be a preference for incorporation of unsaturated acids into the complex lipids, with the exception of the triglycerides. The major saturated fatty acids in the mycelium were palmitic (C(16)) and arachidic (C(20)), whereas the major unsaturated acids were oleic (C(18:1)) and linoleic (C(18:2)), respectively.