Total,polar and neutral lipids ofRhizopus arrhizus fischer

The changes in total lipid content, neutral and polar lipids, total fatty acids, and free fatty acids were investigated over a 4 day period in the zygomycete,Rhizopus arrhizus Fischer. The highest concentration of lipids occurred at the 72 hr period. The degree of unsaturation in the total fatty acid fraction increased during the growth period, whereas the degree of unsaturation decreased in the free fatty acid fraction during the same time period. The ratios of neutral to polar lipids over the 4 day period were: 0.75, 0.22, 1.94 and 0.94. The major components of polar lipids were phosphatidyl ethanolamine, lecithin, lysolecithin, and fatty acids. The fatty acids in the mono- and diglycerides were predominately saturated (67–96%). The fatty acids in the triglycerides shifted from a predominately unaturated (69%, 24 hr) to a more saturated pattern (62%, 96 hr).     

Chemoattraction ofBiomphalaria glabrata (Gastropoda: Planorbidae) to lipid standards and lipophilic factors in leaf lettuce and Tetramin

Chemoattraction of individualBiomphalaria glabrata snails for lipid standards and lipophilic fractions of leaf lettuce and Tetramin were studied in a Petri dish bioassay. Snails were more significantly attracted to a whole Tetramin lipophilic fraction than that of leaf lettuce. Thin-layer chromatography showed that major neutral lipid fractions in Tetramin were triacylglycerols, free fatty acids, and free sterols, and in leaf lettuce were free fatty acids and a mixed free sterol-chlorophyll fraction. Snails were significantly attracted to both the free fatty acid and free sterol fractions from Tetramin, but only to the free fatty acid fraction from leaf lettuce. Snails were significantly attracted to a mixed lipid standard containing equal amounts of phosphatidylcholine, cholesterol, oleic acid, triolein, and cholesteryl oleate. Of four individual neutral lipid standards tested, i.e., cholesterol, oleic acid, triolein, and cholesteryl oleate, snails were only attracted to cholesteryl oleate.     

Lipid composition of normal male rat islets

Lipid composition was studied in fresh isolated isolets from normal male rats. Extractable lipids represent 1856 μg per mg islet protein. In such extracts, phospholipids and neutral lipids reprsent 13.5% and 86.5%, respectively. Phosphatidylcholine (45.8%) and phosphatidyl-ethanolamine (20.6%) were the major components of the phospholipid fraction, and phosphatidylinositol (8.9%) was the minor component. Esterified cholesterol (38.5%), cholesterol (25.5%) and free fatty acids (24.4%) were the major components of the neutral lipid fraction. Fatty major components of the neutral lipid fraction. Fatty acids esterified to phospholipids account for 619.7 pmol/islet, and, 2710 pmol/islet were esterified to neutral lipids. In the phospholipid fraction, saturated and unsaturated fatty acids were in a similar proportion. Conversely, in the neutral lipids, two-thirds of the fatty acids were unsaturated. The ω6 family was the main component of the phospholipid unsaturated fatty acids. In the ω6 and ω3 families, the long-chain fatty acids represent the main components. In the neutral lipid fraction, a different percentage of each family was found: ω3>ω6>ω9. The long-chain polyunsaturated fatty acids were also predominant species in the ω6 and ω3 families. Further studies on the lipid composition of islets, obtained from rats with normal and altered islet functions, could provide new insights into the knowledge of the mechanism of insulin secretion.     

Effect of extraction methods on lipid yield and fatty acid composition of lipid classes containing γ-linolenic acid extracted from fungi

The effect of extraction procedures on the lipid yield and fatty acid composition of total lipid and main lipid structures (phospholipids, diacylglycerols, triacylglycerols, free fatty acids, and sterol esters) of fungal biomass (Mucor mucedo CCF-1384) containing γ-linolenic acid (GLA) was investigated. Seventeen extraction methods, divided into three groups, were tested: six with chloroform/methanol, five with hexane/alcohols, and six with common solvents or mixtures. The chloroform/methanol procedure (2∶1) was selected as standard, where lipid yield (TL/DCW, total lipid per dry cell weight) was 17.8%, considered to be 100% of lipids present. All chloroform/methanol extractions yielded more than 83% recorvey of lipids. Use of hexane/isopropanol solvent systems led to a maximum of 75% recovery. The best lipid yield was achieved by a two-step extraction with ethanol and hexane (120%). Extraction efficiency of the other solvent systems reached a maximum of 73%. Triacylglycerols were the main structures of lipid isolated; only methanol-extracted lipid contained 58.5% phospholipids. The fatty acid content of total recovered lipid was variable and depended on both the lipid class composition and the solvent system. GLA concentrations in total lipids isolated by hexane/alcohol procedures (7.3–10.7%) are comparable with classical chloroform/methanol systems (6.5–10.0%). The maximal GLA yield was obtained with chloroform/methanol/n-butanol/water/0.1 M ethylenediaminetetraacetic acid (EDTA) (2∶1∶1∶1∶0.1, by vol) and after two-step extraction with ethanol and hexane (14.3 and 13.7 g GLA/kg DCW, respectively). The highest GLA content was analyzed in the phospholipid fraction (16.1%) after using chloroform/methanol/n-butanol/water/0.1 M EDTA (2∶1∶1∶1∶0.1, by vol). Remarkably low concentrations of polyunsaturated fatty acids were determined in the free fatty acid fraction.     

Salivary lipid profiles of the leech (Hirudo medicinalis)

Saliva was collected from sixteen leeches (Hirudo medicinalis). The saliva was analyzed for its total lipid content (3.26±0.31 mg of total lipids per 100 mL saliva). The lipids were separated into polar and nonpolar by chromatographic techniques. The neutral fraction was approximately 2/3 of the total, and the polar fraction was approximately 1/3 of the total lipids. Thin-layer chromatography was used to obtain the individual profiles of the polar and nonpolar lipids. Of the identified lipids, phosphatidic acids and free fatty acids represented the largest percentage. These results suggest that the leech contains a unique lipid distribution, and that some of these components may be potent phospholipases and lipases that probably are present in its saliva for the purpose of preventing plugging or healing of the wound in the attacked organism.     

Effect of excessive fatty acid ingestion upon composition of neutral lipids and phospholipids of snailHelix pomatia L.

The effect of an excessive intake of oleic acid on the lipids of the Roman snail (Helix pomatia L.) was studied. The total lipid content increased by 30% which was fully attributable to a marked elevation in the neutral esters and free fatty acids, as phospholipid and free sterol contents remained unaffected. The fatty acid composition of the phospholipids, characterized by high amounts of stearic, linoleic, homolinoleic, and, particularly, arachidonic acids, appeared to be nearly insensitive to this excessive oleic acid ingestion. By contrast, the effect of oleic acid upon the depot lipids was striking: active intestinal resorption of the acid from the dietary supply was shown by the fourfold level of lleic acid in the free fatty acid fraction, whereas a fivefold level of this acid in the glyceride and sterol ester fraction was proof of a substantial esterification. These data support the view that the composition of the structural lipids is specifically species oriented, whereas both the content and the composition of the depot lipids are highly governed by dietary fat intake.     

Intraspecific pairing of planaria,Dugesia tigrina andDugesia dorotocephala (Platyhelminthes: Turbellaria), and observations on lipophilic excretory-secretory worm products

Intraspecific pairing of the planaria,Dugesia tigrina andD. dorotocephala, was studied for 24 hr at 22 ± 1 °C in Petri dish cultures containing an agar substrate and a water overlay. Pairing of fed planaria in the light and dark and starved planaria in the light was studied, and worms in contact or within 5 mm of each other were considered paired. Fed planaria of both species paired significantly in the light and dark, whereas starved planaria did not pair. Our results suggest that worm-emitted chemical factors are involved in intraspecific pairing of planaria. Thin-layer chromatographic analysis was used to study the release of lipophilic worm products. Phospholipids, free sterols, and free fatty acids were detected in all trials, and triglycerides in most. Thin-layer densitometric analysis was used to quantitate the weight of free sterols released by planaria.     

Association of particular systems with the release of neutral lipids inEchinostoma revolutum (Trematoda) adults

Since free sterol excretory-secretory (E-S) products are involved in pheromonal communication in adultEchinostoma revolutum (Trematoda), attempts were made to associate specific systems with the release of lipids from this organism. A micropipet design was used to isolate neutral lipids from the excretory system versus those obtained from both the alimentary and the reproductive systems. Tegumentary lipids were obtained by rubbing the surface of worms with gauze. As determined by thin-layer chromatography, the major neutral lipid obtained from all systems was free sterol. Additional minor neutral lipid fractions were obtained from the excretory, alimentary, and reproductive systems. Histochemical oil red O studies showed neutral lipids only in the excretory system. Neutral lipids released from all of the above-mentioned systems may play a role in pheromonal communication in this species.     

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.     

Changes in flax (Linum usitatissimum L.) seed lipids during germination

Flax (Linum usitatissimum L.) seeds were germinated for 8 d under laboratory conditions, and changes in their lipid fraction were studied by various chemical and chromatographic methods. Total lipid content of the seeds was reduced fourfold at the end of the 8-d germination period as compared to ungerminated seeds on a fresh weight basis. The neutral lipids comprised the major fraction of seed lipids, and triacylglycerols predominated over all other lipid components even during the germination period. Both the spectrophotometric and thin-layer chromatography-flame-ionization detection methods of quantification showed a considerable increase in the content of free fatty acids. The glycolipid fraction of lipids increased, but the phospholipid fraction exhibited only minor changes. Lipase activity of flaxseed increased at the beginning of germination and then remained constant until the fifth day. Phosphatidylcholine was the major phospholipid of flaxseed lipids, and its content was reduced during the germination. The contents of lysophosphatidylcholine and phosphatidic acid increased from negligible amounts to 46% of the total phospholipids. Linolenic, linoleic, and oleic acids, respectively, were the predominant fatty acids of all the lipid fractions of flaxseed, and remained unchanged during the germination period. The glycolipid fraction had the lowest content of polyunsaturated fatty acids. Fatty acids C_14:0, C_20:0, C_24:0, C_20:1, C_22:1, and C_20:5 appeared after d 2 of germination in neutral, glyco- and phospholipid fractions.     

Thermophilic fungi: IV. The lipid composition of six species

The lipid composition of six thermophilic fungi (Myriococcum albomyces, Mucor miehei, Papulaspora thermophila, Rhizopus sp.,Thielavia thermophila (+)Thielavia thermophila (−), andTorula thermophila) was examined. The relative per cent total lipids (4.9–26.3%), neutral lipids (55.5–88.3%), polar lipids (11.7–44.6%) and the fatty acid profile of each lipid fraction was determined. The predominant fatty acids were 16∶0, 18∶0 and 18∶2, and lesser amounts of 12∶0, 14∶0, 15∶0, 16∶1, 16∶2, 17∶0 and 18∶3 were present. The total lipids contained an average of 0.96 double bonds per mole fatty acid (unsaturation index [USI]) the neutral lipids 0.86 USI and the polar lipids 0.84 USI, excluding the values forTorula thermophila. These data show a high degree of saturation and are consistent with data reported for other fungal thermophiles.Torula thermophila possessed abnormally high USI values (1.15–1.50) and was cultured at three different temperatures (25, 45 and 51 C). As the culture temperature ofTorula thermophila increased, the USI decreased. The USI of the polar lipids ofTorula thermophila at 25, 45 and 51 C were 1.50, 1.28 and 1.11, respectively. Thus the membrane lipids of this fungus appear unusual for a thermophile.     

Attraction of 3-Methyl-1-Butanol and Ammonia Identified from Enterobacter agglomerans to Anastrepha suspensa

Tests demonstrated that volatile chemicals emitted from Enterobacter agglomerans, a bacterium that has been isolated from adults as well as fruit infested with larvae of the Caribbean fruit fly, Anastrepha suspensa (Loew) and other pest fruit flies, are attractive to female A. suspensa in laboratory bioassays. 3-Methyl-1-butanol and ammonia were identified as the two primary volatile chemicals released from active cultures of E. agglomerans. No 3-methyl-1-butanol and little ammonia (16.0 g/hr) are released from sterile tryptic soy agar plates. E. agglomerans-inoculated tryptic soy agar plates, however, released an average of 1.5 ± 0.53 g/hr 3-methyl-1-butanol and 332.9 ± 239.16 g/hr ammonia after 24 hr of growth. 3-Methyl-1-butanol lures were formulated in a membrane-based system to provide a constant release rate of synthetic chemical. Release rates ranged from 0.046 ± 0.007 to 12.16 ± 2.76 g/hr. In laboratory tests, equal numbers of females were captured in response to ammonium carbonate lures that released ammonia at the rate of 100 g/hr and to 3-methyl-1-butanol lures that released 12.16 ± 2.756 g/hr of synthetic material. The combination of the two lures was more attractive than ammonia alone. Availability of lures formulated for a range of 3-methyl-1-butanol release rates will facilitate field tests of this putative microbial attractant and may lead to a better understanding of the role of bacteria in the ecology of pest fruit flies.     

Lipid metabolism of brain tissue in culture

Tissue explants from frontal lobes of rat brain were used for the study of cerebral fatty acid metabolism. After tissues had been maintained in serum-supplemented medium, a lipid free medium was substituted and metabolic studies were carried out. Under these conditions explants continued to take up lipid precursors for at least 48 hr. Stearic acid 1-C¹⁴, palmitic acid 1-C¹⁴ and lignoceric acid 1-C¹⁴ were bound to cells as the free fatty acids or incorporafed into neutral lipids (particularly triglycerides), glycolipids and phospholipids. In the galactolipid fraction, cerebrosides were the principal radioactive lipids. Choline phosphoglycerides, ethanolamine phosphoglycerides, inositol phosphoglycerides and serine phosphoglycerides were the principal radioactive phospholipids. Fatty acids were incorporated into cellular lipids either unchanged or after desaturation, chain elongation, or both. In a patient with a demyelinating disease, precursor uptake was reduced and chain elongation and desaturation of the fatty acid was diminished. In a patient with generalized G_M2 gangliosidosis, glycolipids other than cerebrosides were labeled to a greater extent than normal. These studies exemplify the usefulness of tissue explants for prolonged metabolic studies in normal and pathological specimens of brain. One of 13 papers presented at the symposium “Lipid Metabolism in Cells in Culture,” AOCS Meeting, Houston, May, 1971.     

Studies on physicochemical characteristics and fatty acid composition of lipids produced by a strain ofRhodotorula gracilis CFR-1

Rhodotorula gracilis CFR-1 has been evaluated for its potential to produce lipids. The yeast lipids closely resembled palmolein, a liquid fraction of palm oil. It contained 2.3–3% free fatty acids, 64.4% tri-, 23.1% di-, and 6.1% mono-acylglycerols, 94.2% neutral and 5.8% polar lipids. Most abundant fatty acids were C18∶1, C16∶0, C18∶2 and C18∶0 (43.8, 28.5, 13.5 and 4.5%). All fatty acids, irrespective of the levels, followed definite patterns of increase or decrease during the advancement of fermentation. A pincers-shaped curve was obtained when the total saturation and unsaturation were plotted. Use of different glucose and molasses-based media did not show any significant overall effect on saturation (34.4–39.5%) and unsaturation (60.4–65.3%). Desaturation of fatty acids was found to be a metabolic function occurring in the process of cell maturation.     

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.     

Neutral lipid and fatty acid composition of earthworms (Lumbricus terrestris)

Earthworms (Lumbricus terrestris) were extracted with chloroform-methanol (2∶1) and examined primarily for neutral lipids and fatty acids. TLC showed spots for sterols, hydrocarbons, free fatty acids, phospholipids and pigments but none for glycerides (tri-, di- or mono). Saponification of the crude lipid extract yielded 32% fatty acids, 25% unsaponifiables and 43% unidentified. The lipid contained 3% hydrocarbon and 16% sterols. GLC of the hydrocarbons showed at least 13 components. GLC of the sterol fraction showed peaks corresponding to cholesterol (the major component), γ-sitosterol, β-sitosterol, stigmasterol, campesterol, and ergosterol. GLC showed that at least 38 fatty acids were present, with 18∶1, 18∶2, 18∶0, 20∶1 and 17∶0 predominanting. Abstracted in part from the Ph.D. dissertation of J. Cerbulis, Rutgers, The State University, 1966.     

Lipid composition of rat superior cervical ganglion

Excised rat superior cervical ganglion were incubated in Krebs-Ringer solution, freeze-dried, and lipids extracted with chloroform: methanol (2∶1) v/v. Chromatography of lipid extracts in three separate thin layer chromatography solvents was accomplished on a single thin layer chromatography plate coated with acid-washed Silica Gel H. Individual lipids were eluted from the silica gel using a modified Swinny filter holder technique and transesterified with methanolic-BF₃. Fatty acid methyl esters were separated and quantitated by gas liquid chromatography, while phospholipids were determined with a Malachite green dye organic phosphorus assay. Quantitation of neutral lipids was accomplished with a micro Liebermann-Burchard technique and sphingolipids estimated colorimetrically as free sphingosine. The composition of lipids from freezedried rat ganglia resembles the lipid composition of rat brain. Phosphatidylcholine and phosphatidylethanolamine represent 76% of the glycerolphosphatides. The sphingolipids were comprised primarily of sphingomyelin with moderate levels of cerebroside and sulfatide. Cholesterol was the predominant neutral lipid. The major phospholipid fatty acids included palmitic, stearic, and oleic acids. Sumbitted in part as a partial requirement for the Ph.D. degree, State University of New York at Buffalo, Buffalo, N.Y.     

Intraspecific and interspecific chemoattraction inBiomphalaria glabrata andHelisoma trivolvis (Gastropoda: Planorbidae)

A Petri dish bioassay previously used to examine food preferences in planorbid snails was used to study intraspecific and interspecific chemoattraction inBiomphalaria glabrata (albino strain, M-line) andHelisoma trivolvis (Colorado strain) snails.B. glabrata snails showed significant intraspecific chemoattraction in the absence of visual cues and snail thigmotaxis.H. trivolvis snails also showed significant intraspecific chemoattraction. Interspecific chemoattraction between these species occurred in the bioassay, suggesting that the chemoattractants were not species specific. Artificial spring water conditioned by aqueous excretory-secretory products (snail-conditioned water) ofB. glabrata elicited significant intraspecific chemoattraction. However, lipophilic excretory-secretory products ofB. glabrata elicited significant chemorepulsion. Repellant factors in the lipophilic fraction were not characterized.     

High-Performance Thin-Layer Chromatographic Analysis of Sugars in Snail-Conditioned Water and Mucus from Biomphalaria glabrata, Helisoma trivolvis, and Lymnaea elodes

The presence of sugars, particularly glucose, maltose, and sucrose, in the SCW of Biomphalaria glabrata, the two strains of Helisoma trivolvis, and Lymnaea elodes was variable, although only maltose was quantifiable in two samples of snail conditioned waters from B. glabrata. The only sugar detected in mucus was glucose, but it was below the lowest quantifiable amount in the mucus samples of B. glabrata and H. trivolvis. The mean percentage of glucose in the mucus of L. elodes was 0.0040% ± 0.00067%.     

Production of docosahexaenoic acid by Crypthecodinium cohnii grown in a pH-auxostat culture with acetic acid as principal carbon source

Crypthecodinium cohnii, a marine alga used for the commercial production of docosahexaenoic acid (DHA), was cultivated in medium containing sodium acetate as principal carbon source; the pH was maintained at a constant value by addition of acetic acid, which also provided an additional carbon source in a controlled manner. The accumulation of lipid by C. cohnii in this pH-auxostat culture was significantly greater than previously reported for batch cultures using glucose as principal carbon source. Of six strains tested in pH-auxostat cultures, C. cohnii ATCC 30772 was the best, with the cells reaching 20 to 30 g dry weight per liter after 98 to 144 h and containing in excess of 40% (w/w) total lipid, with DHA representing approximately half of the total fatty acids in the triacylglycerol fraction. A productivity of 36 mg DHAL⁻¹ h⁻¹ was achieved during cultivation for 98 h using a 5% (vol/vol) inoculum, and DHA production was in excess of 3 g per liter of culture. Most of the DHA was present in neutral lipids.