Fatty acid composition in lipid fractions lengthwise the mycelium of Mortierella isabellina and lipid production by solid state fermentation

This paper investigates the correlation between mycelial age and fatty acid biosynthesis. The correlation was investigated by analyzing the lipid composition lengthwise the mycelium of the oleaginous fungus Mortierella isabellina, a potential producer of γ-linolenic acid (GLA). Young mycelia were rich in polar lipids (glycolipids plus sphingolipids and phospholipids), while neutral lipid content increased in aged mycelia. In young mycelia, each polar lipid fraction contained almost 40% (w/w) polyunsaturated fatty acids (PUFAs), but this content decreased to less than 30% (w/w) in aged mycelia. On the other hand, PUFA content in neutral lipids fluctuated slightly with age. These results indicate that PUFA biosynthesis is favored in young, fast growing mycelia, while it decreases significantly in aged mycelia. This trend was also observed when we grew M. isabellina on pear pomace, an agro-industrial waste. Pear pomace cultures yielded significant amounts of lipid, which reached 12% (w/w) in dry fermented mass. The produced lipid was rich in GLA and the maximum GLA content in dry fermented mass was 2.9 mg/g.     

Lipid changes of goat sperm plasma membrane during epididymal maturation

Highly purified plasma membranes of maturing goat caput-, corpus- and cauda-epididymal spermatozoa were isolated by aqueous two-phase polymer methods and their lipid constituents were analysed. Phospholipid (approx. 75% w/w), neutral lipid (approx. 15% w/w) and glycolipid (approx. 10% w/w) were the major sperm membrane lipids. There was a significant decrease in the total lipids (approx. 25% w/w), phospholipid (approx. 30% w/w) and glycolipid (approx. 80% w/w) contents of sperm membrane during epididymal maturation. On the contrary, the mature cauda-sperm membrane showed greater (approx. 50% w/w) neutral lipid content than that of the immature caput sperm. Phosphatidylcholine (PC), phosphatidylethanolamine (PE) and sphingomyelin were the phospholipids of the sperm membrane, the former two being the major lipids. Both PC and PE fractions consisted of three species--diacyl, alkylacyl and alkenylacyl forms, the last one being the dominant species in both PC and PE. Of all the phospholipids, diacyl PE decreased most strikingly (approx. 65% w/w) during sperm maturation. The neutral lipid fraction contained sterols, wax esters, 1-O-alkyl-2,3-diacylglycerol, triacylglycerol and fatty acids. Sterols represented nearly 75% w/w of the neutral lipids and cholesterol was the major component (approx. 95% w/w) of the sterol fraction. The sperm maturity was associated with marked increase of sterol (approx. 60% w/w) and steryl ester (approx. 200% w/w) and decrease (approx. 50-65% w/w) of the other membrane-bound neutral lipids. The glycolipid was identified as monogalactosyldiacylglycerol. The fatty acid profile of the various membrane lipids underwent marked alteration during the epididymal transit of the male gametes. Cholesterol/phospholipid and saturated/unsaturated fatty acid ratios increased greatly in the maturing sperm membrane. The altered lipid profile of the mature sperm membrane leads to changes in its fluidity that play an important role in determining the structure and functions of the biomembrane.     

Lipids of the liver microsomal fraction in the ground squirrel <Emphasis Type="Italic">Spermophilus undulatus</Emphasis> during hibernation

Winter sleep of the ground squirrel Spermophilus undulatus was accompanied by a 20% decrease in phospholipid content (µg phospholipid per 1 mg protein) in microsomal fractions of the liver as compared with summer-active squirrels. The phosphatidylcholine level (mol %) in hibernating squirrels was lower than in summer-active squirrels, and the content of sphingomyelin (mol %) during the torpor bout was higher than in winter- and summer-active squirrels. The cholesterol, fatty acid, monoglyceride, and diglyceride levels in the microsomal fraction of the liver were elevated during hibernation. Pronounced seasonal changes in the lipid/protein ratio implicate the lipids of the liver microsomal fraction in adaptation of the ground squirrel to hibernation.     

Action of hydrocortisone on the lipid composition of active and inactive chromatin fractions in the rat liver

A composition of phospholipids and neutral lipids of rat liver chromatin and its active and inactive fractions has been investigated. It is shown that the hydrocortisone action results in marked increase in phospholipid/neutral lipid ratio of both chromatin and its active fraction. The changes in lipid content is clearly expressed in active chromatin fraction, the lipid content of inactive fraction is not changed. It is concluded that the increase of content in certain phospholipids and simultaneous decrease of neutral lipids in chromatin promotes the hormonal activation of genome.     

Liposomal formulations from phospholipids of Greek almond oil. Properties and biological activity

The seeds of the almond tree [(Prunus dulcis (Mill.) D. A. Webb. (syn. Prunus amygdalus)] were collected in two different periods of maturity and were studied for their lipid content. The total lipids (TL) were extracted by the Bligh-Dyer method and the lipid classes have been isolated by chromatographic techniques and were analyzed by HPTLC coupled with a flame ionization detector (HPTLC/FID) and GC-MS. The oils were found to be rich in neutral lipids (89.9% and 96.3% of total lipids) and low in polar lipids (10.1% and 3.7% of total lipids) for the immature and mature seed oils, respectively. The neutral lipid fraction consisted mainly of triacylglycerides whereas the polar lipids mainly consisted of phospholipids. GC-MS data showed that the main fatty acid for both oils was 9-octadecenoic acid (oleic acid). The unsaturated fatty acids were found as high as 89.4% and 89.7%, while the percentage of the saturated fatty acids was found 10.6% and 10.3% for the immature and mature seed oils, respectively. Liposomes were prepared from the isolated phospholipids using the thin lipid film methodology, and their physical properties were characterized. Cytotoxicity was found absent when assayed against normal and cancerous cell lines. These new formulations may have future applications for encapsulation and delivery of drugs and cosmetically active ingredients.     

Characterization of membrane components of the flask-shaped mycoplasma Mycoplasma mobile

The cell membrane of Mycoplasma mobile was isolated by either ultrasonic or French press treatment of intact cells. The membrane fraction contained all of the cellular lipids, but only one-third of cellular proteins and had a density of 1.14 g ml-1. The soluble fraction contained the NADH dehydrogenase activity of the cells, as well as a protein with an apparent molecular mass of 55 kDa that was phosphorylated in the presence of ATP. Lipid analyses of M. mobile membranes revealed that membrane lipid could be labelled by radioactive glycerol, oleate and to a much higher extent by palmitate but not by acetic acid. The membrane lipid fraction was composed of 54% neutral and 46% polar lipid. The major constituents of the neutral lipid fraction were free fatty acid, free cholesterol and cholesterol esters (45, 25 and 20%, respectively, of total neutral lipid fraction). The free cholesterol count was 13% (w/w) of total membrane lipids with a cholesterol:phospholipid molar ratio of about 0.9. Among the polar lipids, both phospho- and glycolipids were detected. The phospholipid fraction consisted of a major de novo-synthesized phosphatidylglycerol (approximately 63% of total phospholipids), plus exogenous phosphatidylcholine and sphingomyelin incorporated in an unchanged form from the growth medium. The glycolipid fraction was dominated by a single glycolipid (approximately 90% of total glycolipids) that was preferentially labelled by palmitic acid and showed a very high saturated:unsaturated fatty acids ratio.     

Fractionation and lipase-catalyzed conversion of microalgal lipids to biodiesel

This study was conducted to evaluate the lipid fractionation and purification procedures of lipase-catalyzed conversion of neutral lipids to microalgal biodiesel. Microalgae lipids were efficiently recovered and purified by a combined extraction method and crude lipid extracts were separated into neutral lipids, glycolipids, and phospholipids by solid-phase extraction. The high purity of the neutral lipids fraction was confirmed by its low concentration of phosphorous (< 2.0 ppm). Transesterification was catalyzed by immobilized Candida antarctica lipase for 72 h with stepwise addition of methanol. The reaction displayed Michaelis–Menten kinetics and produced high yields of microalgal biodiesel (91.2% in the case of Dunaliella salina) with a high content of unsaturated fatty acids (81.5%). Neutral lipids were converted to biodiesel by three-step transesterification, while the removal of polar lipids maintained the activity of the immobilized lipase by reducing both reaction mixture viscosity and contamination risk.     

Lipid analysis of Greek walnut oil (Juglans regia L.)

The walnut oil (Juglans regia L.) total lipids (TL) were extracted by the Bligh-Dyer method and the lipid classes have been isolated by chromatographic techniques and they were analyzed by high performance thin layer chromatography (HPTLC)/FID and GC-MS. The oil was found to be rich in neutral lipids (96.9% of total lipids) and low in polar lipids (3.1% of total lipids). The neutral lipid fraction consisted mainly of triacylglycerides whereas the polar lipids mainly consisted of sphingolipids. GC-MS data showed that the main fatty acid was linoleic acid. Unsaturated fatty acids were found as high as 85%, while the percentage of the saturated fatty acids was found 15%. Two types of liposomes were prepared from the isolated walnut oil phospholipids and characterized as new formulations. These formulations may have future applications for encapsulation and delivery of drugs and cosmetic active ingredients.     

Phospholipids from Bacillus stearothermophilus

The lipids of Bacillus stearothermophilus strain 2184 were extracted with chloroform-methanol and separated into neutral lipid and three phospholipid fractions by chromatography on silicic acid columns. The phospholipids were identified by specific staining reactions on silicic acid-impregnated paper, by chromatography of alkaline and acid hydrolysis products, and by determination of acyl ester:glycerol:nitrogen:phosphorus molar ratios. The total extractable lipid was 8% of the dry weight of whole cells and consisted of 30 to 40% neutral lipid and 60 to 70% phospholipid. The phospholipid consisted of diphosphatidyl glycerol (23 to 42%), phosphatidyl glycerol (22 to 39%), and phosphatidyl ethanolamine (21 to 32%). The concentrations of diphosphatidyl glycerol and phosphatidyl glycerol were lower in 2-hr cells than in 4- and 8-hr cells. Whole cells were fractionated by sonic treatment and differential centrifugation. The total lipid content, expressed in per cent of dry weight of each fraction was: whole protoplasts, 10%; membrane fraction, 18%; 30,000 x g particulate fraction, 22%; and 105,000 x g particulate fraction, 26%. The relative phospholipid concentrations in each fraction were about the same. As had been previously reported, none of the phospholipid was stable to alkaline hydrolysis.     

Lipid composition of the fishes Heterotis niloticus,Brycenus nurse,Gnathonemus cyprinoides and Sarotherodon galilaeus from a small lake in Nigeria

Lipid composition of Heterotis niloticus, Brycenus nurse, Gnathonemus cyprinoides and Sarotherodon galilaeus, which vary in scale thickness, were studied. Heterotis niloticus (very thick scales) had the lowest lipid content (13%), while G. cyprinoids (light scales) had the highest lipid content (26%). The common neutral lipids were cholesterol, free fatty acids and cholesterol esters, while diphosphatidyl glycerol, phosphatidyl glycerol and phosphatidyl ethanolamine were the most predominant phospholipids.     

Lipids of Thermoplasma acidophilum

Cells of Thermoplasma acidophilum contain about 3% total lipid on a dry weight basis. Total lipid was found to contain 17.5% neutral lipid, 25.1% glycolipid, and 56.6% phospholipid by chromatography on silicic acid. The lipids contain almost no fatty acid ester groups but appear to have long-chain alkyl groups in ether linkages to glycerol. The phospholipid fraction includes a major component which represents about 80% of the lipid phosphorus and 46% of the total lipids. We believe this component to be a long-chain isopranol glycerol diether analogue of glycerolphosphoryl monoglycosyl diglyceride. The glycolipids appear to contain isopranol diether analogues. Several components of the complex, neutral lipid fraction have been identified as hydrocarbons, vitamin K(2)-7, and isopranol glycerol diether analogues. Sterols are present in the neutral lipids but do not appear to be synthesized by the organism.     

Isolation and composition of the carotenoid-containing oil droplets from cone photoreceptors.

A procedure for isolating the carotenoid-containing oil droplets of cone retinal photoreceptors of Gallus domesticus is described. The oil droplets, composed almost entirely of neutral lipids and carotenoids, have been separated into ten chromatographic components. Similar separations have been carried out on the total retinal neutral lipids for comparison. The neutral lipids represented 26.1% of the total retinal lipid. Cholesterol, cholesterol ester, mono-, di- and triacylglycerols represented 92.6% of the total neutral lipid. Each of these and other minor neutral lipid components were also present in the lipids extracted from the isolated oil droplets in correspondingly similar concentrations. However, the concentrations of carotenoids were greatly enriched in the neutral lipids of the oil droplets. Each of the major fatty acyl-containing neutral lipids from the chromatography of oil droplet lipids is greatly enriched in polyunsaturated fatty acids when compared with the corresponding component from the total neutral lipid chromatography. In the acylglycerols and free fatty acid fraction from the oil droplets, linoleic and arachidonic acid together represented 52-83% of the total polyunsaturated fatty acids present. The remainder was generally distributed about equally among six other acids. Except for the diacylglycerol fraction, linoleic acid was usually the most enriched acid in a specific oil droplet fraction when compared with any other polyunsaturated fatty acids. A similar pattern of polyunsaturated fatty acid enrichment observed in the fatty acids of the outer segment phospholipids relative to the corresponding total phospholipid fractions of this cone rich retina (Johnston, D. and Hudson, R.A. (1974) Biochim. Biophys. Acta 369, 269) suggest possible metabolic relationships between the oil droplet neutral lipids and the outer segment membrane phospholipids of the cone photoreceptors. A mechanism for the accumulation of the carotenoids in the oil droplets is also discussed.     

Sphingolipid composition of human platelets

Total lipid extracts from washed trypsinized human platelets were fractionated into neutral lipids, glycosphingolipids, and phospholipids by silicic acid chromatography. The concentrations and chemical structures of the neutral and acidic glycosphingolipids were then studied in detail. On the basis of sugar molar ratios, studies of permethylation products, and the action of stereospecific glycosidases on the lipids, identifications were made of four neutral glycosphingolipids. Lactosylceramide was the most abundant type and accounted for 64% of the total neutral glycolipid mixture. The major fatty acids of the lactosylceramide were 20:0, 22:0, 24:0, and 24:1; the major long-chain base was 4-sphingenine. The platelets were surprisingly rich in a ceramide fraction, which represented 1.3% of the total platelet lipids. It had a different fatty acid composition than the neutral glycosphingolipid and ganglioside fractions. Hematoside was also isolated from the total lipid fraction of platelets; the neuraminic acid component was N-acetylneuraminic acid. Treatment of platelets with trypsin, chymotrypsin, or thrombin increased the yield of hematoside as compared with a control, while the level of ceramides was not changed. It was concluded that the platelets are similar to leukocytes, liver, and spleen in that lactosylceramide and hematoside are the principal neutral and acidic glycosphingolipids. The presence of a relatively high proportion of ceramide in platelets may be a unique characteristic of this cellular fraction of blood.     

Presence of phospholipid-neutral lipid complex structures in atherosclerotic lesions as detected by a novel monoclonal antibody.

A novel monoclonal antibody (ASH1a/256C) that recognizes atherosclerotic lesions in human and Watanabe heritable hyperlipidemic (WHHL) rabbit aortae is described. When (123)I-labeled ASH1a/256C antibody is injected intravenously into WHHL rabbits, it associates specifically with fatty streaks on the aorta. The antigen recognized by the antibody is lipid, based on extraction with chloroform and methanol from WHHL rabbit tissues. The antigen, purified by high performance liquid chromatography, was shown to be phosphatidylcholine (PC), which contains unsaturated fatty acyl groups based on analyses utilizing (1)H and (13)C nuclear magnetic resonance, Fourier transfer-infrared spectrum, and mass spectrometry. The antibody did not react with other classes of phospholipids or neutral lipids when tested using an enzyme-linked immunosorbent assay. When PC was mixed with either cholesterol, cholesteryl ester, or triacylglycerol, however, the reactivity of the antibody to PC increased up to 8-fold. Homogenates of aorta tissue obtained from normal and WHHL rabbits were fractionated using sucrose density gradient ultracentrifugation in which neutral lipid droplets, cellular membranes, and proteins are separated. The phospholipid content in cellular membrane fractions from WHHL rabbits was twice as high as that of normal rabbits, and there was an enormous difference in the antigenic activity in these fractions. The content of cholesterol in the cellular membrane fraction of WHHL rabbits was approximately 50 times higher than that of normal rabbits. Addition of neutral lipids to the cellular membrane fraction of normal rabbit markedly increased the antigenic activity. Atheromatous lesions in thickened WHHL rabbit aortic intima that were rich in lipid droplets were stained positively with ASH1a/256C immunohistochemically. These results strongly suggest that PC-neutral lipid complex domains are formed in atherosclerotic lesions.     

Comparative analysis of lipid composition in axenic strains of Blastocystis hominis.

1. Six axenic strains of Blastocystis hominis varied in content of lipids from 12 to 43 pg total lipid/cell. With all strains, phospholipid content was about 39% of total lipids. 2. Neutral lipid fractions of B. hominis were resolved into nine constituents, of which seven were identified tentatively. Sterol esters, principally esters of cholesterol, were the major neutral lipid constituent, accounting for 49-63% of the neutral lipids, and at least 30% of the total lipids. 3. Polar lipids were resolved into eleven constituents, of which nine were identified tentatively. Phosphatidylcholine was the major polar lipid constituent of all strains, accounting for 53-63% of the polar lipids, and about 22% of the total lipids.     

Lipids noncovalently associated with keratins and other cytoskeletal proteins of mouse mammary epithelial cells in primary culture

Lipids noncovalently associated with cytoskeletal (CS) proteins of mouse mammary epithelial cells (MMEC) grown in primary culture were analyzed. A CS fraction, preapred by subjecting MMEC to 1.5 KCl and 1% Triton X-100 in phosphate buffered saline (pH 7.4), was extracted 4–6 times with chloroform/methanol. Thin-layer chromatography (TLC) indicated that in comparison to whole cell lipid extracts, CS lipids consisted mostly of neutral lipids, especially triacylglycerols and, possibly cholesteryl esters. TLC analysis of chloroform/methanol CS extracts prepared from MMEC that had been incubated 4 h in [³H]palmitate revealed similar results, with the majority of label appearing in triacylglycerols and other neutral lipids. By autoradiography of sodium dodecyl sulfate polyacrylamide gels, all of the major CS proteins appeared labelled. The major regions of autoradiographic density of the gel were excised, the protein solubilized, and the lipids extracted and subjected to TLC. Most of the radiolabel appeared at the origin and ion front and resolved as neutral lipids. In contrast, keratins of 54–55 kDa and 46 kDa appeared to be associated noncovalently with a higher ratio of polar lipids (possibly phospholipids) to nonpolar (neutral lipids). Very little radioactivity, mostly neutral lipid, was associated with actin. A previously unidentified CS component of 30 kDa had primarily noncovalently bound neutral lipid. The results are discussed in terms of the apparent interactions of keratin filaments with the plasma membrane, nuclear envelope and cytoplasmic organelles.     

Lipids noncovalently associated with keratins and other cytoskeletal proteins of mouse mammary epithelial cells in primary culture.

Lipids noncovalently associated with cytoskeletal (CS) proteins of mouse mammary epithelial cells (MMEC) grown in primary culture were analyzed. A CS fraction, prepared by subjecting MMEC to 1.5 M KCl and 1% Triton X-100 in phosphate buffered saline (pH 7.4), was extracted 4-6 times with chloroform/methanol. Thin-layer chromatography (TLC) indicated that in comparison to whole cell lipid extracts, CS lipids consisted mostly of neutral lipids, especially triacylglycerols and, possibly cholesteryl esters. TLC analysis of chloroform/methanol CS extracts prepared from MMEC that had been incubated 4 h in [3H]palmitate revealed similar results, with the majority of label appearing in triacylglycerols and other neutral lipids. By autoradiography of sodium dodecyl sulfate polyacrylamide gels, all of the major CS proteins appeared labelled. The major regions of autoradiographic density of the gel were excised, the protein solubilized, and the lipids extracted and subjected to TLC. Most of the radiolabel appeared at the origin and ion front and resolved as neutral lipids. In contrast, keratins of 54-55 kDa and 46 kDa appeared to be associated noncovalently with a higher ratio of polar lipids (possibly phospholipids) to nonpolar (neutral lipids). Very little radioactivity, mostly neutral lipid, was associated with actin. A previously unidentified CS component of 30 kDa had primarily noncovalently bound neutral lipid. The results are discussed in terms of the apparent interactions of keratin filaments with the plasma membrane, nuclear envelope and cytoplasmic organelles.     

Lipid quality of the diatoms Skeletonema costatum and Navicula gregaria from the South Atlantic Coast (Argentina): evaluation of its suitability as biodiesel feedstock

Since the fatty acid ester profile of a given biofuel is relatively consistent with the source’s fatty acid profile, the properties of the biodiesel produced from a particular feedstock exhibit predictable quality. Thus, lipid fractions and the fatty acid composition of stationary growth-phase cultures of the local strains of the diatoms Skeletonema costatum and Navicula gregaria were analysed to evaluate their suitability as biodiesel feedstock. Total lipid content was 20.83 pg cell⁻¹ in S. costatum and 19.17 pg cell⁻¹ in N. gregaria. Neutral lipids were the main fraction of total lipids in both species, accounting for ca. 65% and 76%, respectively. S. costatum was predominant in saturated fatty acids (SFAs; 43.48 %) and monounsaturated fatty acids (MUFAs; 40.11%), while N. gregaria was predominant in MUFAs (54.85%), followed by SFAs (33.42%). In S. costatum, the main fatty acids in neutral lipid fraction were myristic, palmitic, palmitoleic and oleic acids, while the main ones in N. gregaria were palmitic and palmitoleic acids. The oils extracted from these species presented linolenic acid contents within biodiesel’s quality specifications. However, in neutral lipid fraction both species showed eicosapentaenoic acid levels higher than the required limit. The lipid quality analysed in both species suggests that a biodiesel derived from these oils may present an acceptable cetane number, but likely poor cold-flow properties. This baseline information is useful for future research tending to find more suitable conditions in order to improve oil yield. In addition, both estuarine species neither compete with agriculture for food nor require farmland nor fresh water.     

Influence of stressful fermentation conditions on neutral lipids of a Saccharomyces cerevisiae brewing strain

The neutral lipid fraction of the aerobically grown starter yeast culture of a Saccharomyces cerevisiae brewing strain, and three-first recycled yeast generations exposed to multiple stress factors during beer fermentation was studied. No pronounced changes in the cellular neutral lipid content between the non-stressed starter and stressed recycled cells were found. However, it was found that recycled yeast generations modulate their neutral lipid composition during fermentation. The ergosterol content was increased at the expense of steryl esters (SEs) and squalene, which resulted in a higher ergosterol/SEs molar ratio and a slightly higher ergosterol/squalene molar ratio. In addition, the proportion of unsaturated fatty acids, mainly palmitoleic acid increased in the neutral lipid fraction of the stressed recycled yeast generations. These results suggest that some specific neutral lipid species and fatty acids stored in the neutral lipid fraction are involved in the adaptive response of the brewer’s yeast to stressful fermentation conditions. The striking finding was a high squalene content in the neutral lipid fraction of both the starter yeast culture and recycled yeast generations (22.4 vs. 19–20%, respectively), implying a possible biotechnological exploitation of this biologically active molecule from the yeast biomass.     

Lipids and fatty acid composition of developing winged bean seeds

The moisture, lipids and fatty acid composition of developing winged bean (Psophocarpus tetragonolobus) seeds were studied. The moisture content decreased steadily as the seeds matured. The lipid content increased gradually and reached a maximum ca 6 weeks after flowering (WAF). In the early stage (2 WAF) of the developing seeds there were more polar lipids (glycolipids and phospholipids) than neutral lipids but, as the seeds developed, neutral lipids gradually accumulated while the polar lipids decreased until 6 WAF. Thereafter, both the neutral lipid and polar lipid levels remained little changed. The amounts of palmitic and stearic acids decreased, but the level of behenic acid increased as the seeds matured. On the other hand, the oleic acid content increased while that of linolenic acid decreased rapidly as the seeds matured. The concentration of linoleic acid, however, fluctuated during the development of the seeds.