bluuebunny/crossref_metadata_2025 huggingface dataset:
New sources of 9‐d‐hydroxy‐cis‐12‐octadecenoic acid
Authors: Powell R. G. , Kleiman R. , Smith C. R.
Published: November 2006

9‐d‐Hydroxy‐cis‐12‐octadecenoic acid has been isolated from 3 seed oils of the family Apocynaceae:Holarrhena antidysenterica (73%),Nerium oleander (11%) andNerium indicum (8%). The known occurrence of this acid was previously limited to the genusStrophanthus (9–15%). A mixture of unusual tetra‐acid glycerides was isolated fromN. oleander oil by thin layer chromatography. Pancreatic lipase hydrolysis of the glyceride mixture showed that 9‐d‐acetoxy‐cis‐12‐octadecenoic acid is esterified exclusively at an α‐glycerol position and that normal fatty acids occupy the remaining 2 glycerol positions. A portion of the hydroxy acid inN. indicum oil was also acetylated, however, no acetate was found in eitherH. antidysenterica orStrophanthus hispidus oils.
Molecular species of phosphatidyl ethanolamine from egg yolk
Authors: Holub B. J. , Kuksis A.
Published: November 2006

Phosphatidyl ethanolamine was isolated from total egg yolk lipids by preparative thin layer chromatography (TLC). The purified phosphatide contained 3% of the alkoxy derivative. It was degraded to diglycerides in the presence of purified sphingomyelin by phospholipase C fromClostridium welchii. The diglycerides were acetylated and resolved on the basis of unsaturation by argentation TLC. The fatty acid composition of the original phosphatidyl ethanolamine and the derived acetates was determined by gas chromatography, as was the molecular weight distribution of the diglyceride acetates. The placement of the fatty acids in the parent phosphatide was deduced by hydrolysis with phospholipase A fromCrotalus atrox, and in the acetates with pancreatic lipase. Some 33 major species of phosphatidyl ethanolamine were identified and compared to those for egg yolk lecithins.
Bio‐oxidation of linoleic acid via methylmalonyl‐CoA
Authors: Dupont Jacqueline , Mathias Melvin M.
Published: November 2006

Unsaturated long‐chain fatty acids are oxidized more rapidly than are saturated fatty acids of similar chain length in intact animals and isolated mitochondria. Gamma‐oxidation of the 3‐dodecenoic acid intermediate in beta‐oxidation of oleate would yield propionate which is metabolized via methylmalonate.14C‐labeled fatty acids were administered to intact rats, muscle homogenates and lysed mitochondria. Methylmalonate, succinate and CO2 were isolated and14C determined. Incorporation of U‐14C‐linoleate into methylmalonate in vitro was 20 times greater than from U‐14C‐palmitate. Rats fed 20% corn oil grew more slowly on B12 deficient than B12 sufficient diets. Biotin and vitamin B12 deficiencies were found to decrease the in vivo metabolism of linoleate. These data suggest that one pathway of linoleate oxidation has methylmalonate as an intermediate.
A comparative study of gangliosides from the brains of various species
Authors: Schengrund C. ‐L. , Garrigan O. W.
Published: November 2006

A comparison is made of the sialic acid and hexose content of crude gangliosides from the brains of 13 species, including mammals, a bird, and amphibian, a reptile and fish. The sialic acid content is relatively constant from species to species. Gangliosides are less abundant in tissues other than the brain. Four species (cat, dog, pig and sheep) were selected for the determination of their major ganglioside subfractions. The ganglioside subfractions were isolated (after extraction and partition dialysis) using descending thin layer chromatography. The population of ganglioside molecules varied from species to species. From dog and sheep a mono‐, a di‐ and a trisialoganglioside were obtained; from cat a mono‐, a di‐ and two trisialogangliosides; and from pig a mono‐ and two disialogangliosides. Each ganglioside subfraction was found to contain glucose, galactose and galactosamine in the ratio of approximately 1∶2∶1. The fatty acid moieties consisted of more than 80% stearic acid with lesser amounts of arachidic, palmitic and behenic acid. Sphingosine analyses indicated ratios of sphingosine to icosisphingosine of 7∶3 for the monosialo‐, 1∶1 for the disialo‐ and 3∶7 for the trisialogangliosides.
Essential fatty acid‐deficient rats: II. On the fatty acid composition of partially hydrogenated arachis, soybean and herring oils and of normal, refined arachis oil
Authors: Hølmer G. , Aaes‐Jørgensen E.
Published: November 2006

The fatty acid composition of partially hydrogenated arachis (HAO), partially hydrogenated soybean (HSO) and partially hydrogenated herring (HHO) oils and of a normal, refined arachis oil (AO) was studied in detail by means of direct gas liquid chromatography, ultraviolet and infrared spectrophotometry and by thin layer chromatography fractionation on silver nitrate‐silica gel plates followed by gas liquid chromatography. It was shown that the partially hydrogenated oils all contained fatty acids withtrans double bonds. In the plant oils, thetrans acids were present mainly as elaidic acid. The HHO showed an almost equal distribution betweentrans 18∶1 ω9,trans 20∶1 ω>9 andtrans 22∶1 ω>9. Sometrans configuration was also found in the C20‐and C22‐dienes and trienes of the HHO. In all the oils, conjugated fatty acids were present in minor amounts only (<0.5%). Special attention was given to the ω‐acids known to be of specific nutritional value. The HSO contained about 32% linoleic acid, whereas the content ofcis, trans+trans, cis andtrans, trans octadecadienoic isomers was 1.7% and 0.5%, respectively. The amount of linoleic acid in the HSO was even higher than that of AO (29%). The HAO contained only 0.8% 18∶2 ω6 (linoleic acid). Further, two 18∶2 fatty acids with ω>6, acis, cis and atrans, trans isomer, were present in small amounts. The HHO contained 0.5% 18∶2 ω6 (linoleic acid). Isomers of 18∶2 ω>6 were also found in the HHO. They may be hydrogenation products of higher unsaturated C18‐acids orginally present. All the C20‐ and C22‐dienes and trienes were shown to have an ω‐chain greater than 6. Fatty acids with ω6‐structure were not formed during partial hydrogenation of the oils studied.
Differential incorporation of acetate and glucose in maturing douglas fir seeds
Authors: Te Ching May , Fang S. C.
Published: November 2006

In order to discern the synthetic pathways of lipids in coniferous seeds, decoated maturing Douglas fir seeds were incubated with 2‐14C‐acetate and ul‐14C‐glucose for 3 hr in phosphate buffer at pH 6.0. About 52% of incorporated acetate was found in lipids, but only 9% of the absorbed glucose was converted to lipids. Distribution of incorporated radioactivity in lipid classes was similar for both substrates, 45% in polar lipids, 22% in diglycerides, 15% in triglcerides, 7% in sterol esters, 4% in each of fatty acids and monoglycerides, and 3% in sterols. High specific activity was found in free fatty acids, diglycerides, monoglycerides and polar lipids indicating a rapid turnover of the intermediates for reserve triglycerides and structural polar lipids. Degradation analyses showed that 50% of incorporated acetate and glucose in lipids were in fatty acid moiety. Acetate contributed more in sterols and other unsaponifiables than in glycerol, and the reverse was true for glucose. All the data indicated that acetate is the direct precursor of fatty acids and sterols. General synthetic pathways prevail in fir seeds. Methods for complete analysis of chemical and radio‐chemical composition were presented and results discussed.
The effects of catecholamines on the distribution of14C‐cholesterol in dogs
Authors: Gans Joseph H. , Cater Marilyn R.
Published: November 2006

Fifteen adult male pure bred Beagle dogs were given 4‐14C‐cholesterol and a subsequent 18 day period was permitted to elapse for equilibration of the14C‐cholesterol between blood and tissue compartments. Peanut oil, epinephrine in oil or norepinephrine in oil was administered by daily subcutaneous injections over a period of 63 to 81 days. Epinephrine but not norepinephrine resulted in sustained increases in plasma cholesterol concentrations. The half‐life of14C‐cholesterol in plasma was 19 days in control dogs, 18 days in catecholamine treated dogs. The slope of the decline in the specific radioactivity of plasma cholesterol did not change during epinephrine administration, suggesting an influx into plasma of endogenous cholesterol. Specific radioactivity of thoracic aorta cholesterol was fourfold greater than that of plasma cholesterol in control dogs at the end of the experiment and 1.3‐fold greater than the specific radioactivity of cholesterol in the lower aortic segments. Treatment with epinephrine decreased the specific radioactivity cholesterol in all segments of the aorta and resulted in cholesterol specific radioactivity from thoracic aorta which was less than that of cholesterol from the lower aortic segments. Norepinephrine treatment resulted in decreases in the specific radioactivity of cholesterol from the thoracic and abdominal aortic segments but the changes were smaller than those observed in epinephrine treated dogs.
Desaturation of palmitate and stearate by cell‐free fractions from soybean cotyledons
Authors: Inkpen James A. , Quackenbush Forrest W.
Published: November 2006

Homogenates of cotyledons from immature soybean seeds were fractionated by centrifugation. Cell‐free preparations actively desaturated 1‐14C‐palmitate and 1‐14C‐stearate to produce 9,10‐unsaturated acids. The 9‐desaturase activity was present mainly in supernatant fractions (22,000 and 105,000 xg). These fractions also desaturated oleate to linoleate and elongated C14, C16 and C18 acids. In view of this versatility of desaturase systems in the soybean, including the 9‐desaturase(s) for C14, C16 and C18 saturated acids, there would not seem to be further need to consider a separate plant pathway for biosynthesis of unsaturated fatty acids.
Composition and biosynthesis of the major hexose containing sphingolipids of pig leucocytes
Authors: Levis Gabriel M.
Published: November 2006

The oligohexosyl ceramides of two preparations of blood leucocytes taken from large white pigs, weighing 80 kg were analyzed and found to comprise as major constituents trihexosyl ceramide, with glucose‐galactose in a molar ratio of 1∶2, and glucosyl ceramide. The mean value of the two preparations was 4.9% and 1.35% of the total lipids, respectively, for the two glycolipids. Lactosyl ceramide is the major component of human leucocytes, in contrast to the pig leucocytes where it was detected in minor quantities. U‐14C‐glucose, incubated with bone marrow cells of young pigs (20 kg living weight), was mainly incorporated into the carbohydrate moiety of glucosyl ceramide and trihexosyl ceramide. Further analysis of this compound indicated that all three hexoses were labeled with14C and that the glucose attached to the ceramide had the highest specific activity. Time studies showed a decline in the incorporation of14C into glucosyl ceramide as compared to its incorporation into trihexosyl ceramide.
A new criterion in the bioassay of essential fatty acids: the spontaneous swelling of rat liver mitochondria in vitro
Authors: Houtsmuller U. M. T. , Van Der Beek A. , Zaalberg J.
Published: November 2006

The spontaneous swelling in vitro of liver mitochondria from rats deficient in essential fatty acids (EFA) and normal rats is compared using the change in optical density as a criterion. Differences between both groups are observed only if high sucrose concentrations are used for the isolation of the mitochondria. The change in optical density can be described mathematically by the sum of two exponential functions. A correlation is found between the parameters of this function and the dose of sunflower seed oil fed to EFA‐deficient rats, which makes the method useful as a criterion in an EFA bioassay. The EFA activities of several synthetic polyunsaturated fatty acids are compared using either growth rate or mitochondrial swelling as a criterion.
Biosynthesis of fatty acids in cell‐free homogenates of lactating gerbil mammary gland
Authors: Coniglio John G. , Bridges Raymond B.
Published: November 2006

Cell‐free homogenates of lactating mammary gland of gerbils maintained on a diet of sunflower seed, guinea pig chow and oats (Diet 1) or a diet of guinea pig chow and oats (Diet 2) and of rats maintained on laboratory chow (Diet 3) were incubated with14C‐labeled acetate, acetyl CoA or malonyl CoA aerobically. A large proportion of the14C from14C‐acetate and14C‐acetyl CoA incorporated into fatty acids by homogenates from gerbils on Diet 1 was in unsaturated compounds, particularly in 18‐carbon and 20‐carbon dienoic acids, compared to preparations from animals on Diets 2 or 3. The two radioactive dienoic acids were proven to be Δ9,12 18∶2 and Δ11,14 20∶2, and the latter was shown to be a direct elongation product of Δ9,12 18∶2 by the substrate14C‐acetyl CoA. In all experiments14C from14C‐malonyl CoA was incorporated predominantly into 14∶0 and 16∶0, and very little incorporation occurred into unsaturated fatty acids in homogenates made either from gerbil or rat. Total fatty acids isolated from homogenates and from milk fat (fat floating on the centrifuged homogenates) of gerbils on Diet 1 had a higher proportion of 18∶2 than animals on the other two diets, a reflection of the large dietary intake of linoleic acid by gerbils on Diet 1. Under these conditions the amount of 18∶2 in the mammary gland had a significant effect on the products of the incubation.
Peroxidation of microsomal membrane protein—Lipid complexes
Authors: Victoria Edward J. , Barber Albert A.
Published: November 2006

Nonenzymatic lipid peroxidation was studied using the TBA test on rat liver microsomal fractions, lipid micelles and structural protein‐lipid micelle complexes. The kinetics, response to divalent cations, and iron‐ascorbate catalysis were alike in the microsomal fraction and in the complex, but different in lipid micelles. The structural protein represented 41% of the total membrane protein, had a S20,obs of 3.5 and was hydrophobic. The binding of lipid micelles by structural protein proceeded in two steps, with an initial fast rate followed by a slower rate. The binding appeared to involve a hyrophobic association between lipid and protein as evidenced by insensitivity to pH, ionic strength and lack of preference for the individual classes of phospholipid micelles. Deoxycholate caused an increase in the initial peroxidation rate in microsomal fractions. Iron and ascorbate catalyzed lipid peroxidation in both the microsomal fraction and in the complex. Iron catalyzed lipid peroxidation but calcium, cobalt and copper inhibited the reaction in the SP‐lipid micelle complex. Lipid peroxidation in microsomal suspensions, therefore, appears to be determined, in part, by the hydrophobic nature of the protein‐lipid association found in membranes.
Species variations in phospholipid class distribution of organs: I. Kidney, liver and spleen
Authors: Rouser George , Simon Gerald , Kritchevsky Gene
Published: November 2006

Improved procedures for preparation of lipid extracts and determination of phospholipids by phosphorus analysis of spots separated by thin layer chromatography (TLC) were employed to determine the phospholipid class distributions of vertebrate (human, bovine, rat, mouse, frog) kidney, liver and spleen. The absence of significant changes arising from postmortem enzymatic degradation was demonstrated by analysis of lipids of organs after standing for different times postmortem. Intraspecies variability was evaluated by separate analysis of several rat organs. Accuracy of analytical results was insured by demonstrating the absence of spot overlap by two‐dimensional TLC and low values for standard deviations. The values for kidney and liver demonstrate little or no species variability, whereas values for spleen indicate two groups which differ in cellular composition. The findings for kidney and liver are in keeping with data obtained from heart, skeletal muscle, lung and highly purified subcellular particulates which indicate that, among vertebrates, there is little or no species variability of phospholipid class distribution of organs and most subcellular particulates.
A cyanogenetic lipid fromCordia verbenacea DC. Seed oil
Authors: Mikolajczak K. L. , Seigler D. S. , Smith C. R. , Wolff I. A. , Bates R. B.
Published: November 2006

Cyanogenetic nonglycerol diesters, which are composed of two fatty acid moieties esterified with an unsaturated five‐carbon dihydroxynitrile, constitute 35% ofCordia verbenacea DC. (Boraginaceae) seed oil.
Oxidation of α‐tocopherol to α‐tocopheryl quinone by carbon tetrachloride‐ethanol solvent
Authors: Seward C. R. , Mitchell G. Vaughan , Argrett L. C. , Hove E. L.
Published: November 2006

The addition of small amounts of CCl4 to ethanolic solutions of α‐tocopherol, vitamin A acetate or β‐carotene caused destruction of these fat‐soluble compounds. The oxidation product of α‐tocopherol was identified as α‐tocopheryl quinone by UV and IR spectral analysis. Maximum conversion to the quinone occurred with a ratio of CCl4 to ethanol of 25∶75 (v/v).
Influence of rabbit milk upon cholesterolaemic response of offspring of rabbits
Authors: Roberts D. C. K. , West C. E.
Published: November 2006

The milk lipids from the dams of two strains of rabbits differing in their cholesterolaemic response, one hyperresponsive and one hyporesponsive to dietary cholesterol, were analyzed. The hyperresponsive dams had significantly higher (P<0.05) cholesterol and phospholipid concentrations than the hyporesponsive dams but similar triglyceride concentrations. Cross fostering experiments with hyporesponsive and hyperresponsive offspring were carried out. Offspring from hyporesponsive parents suckled on hyper‐responsive dams resembled hyperresponsive offspring in their cholesterolaemic response. However, offspring from hyper‐responsive parents responded as hyper‐responsive whether they were raised on their natural dams or on foster hyporesponsive dams. We conclude that the trait for hyperresponder characteristics is un‐influenced by rabbit milk, while the trait for hyporesponder characteristics is dependent upon the cholesterol and phospholipid concentrations in milk.
In vitro incorporation of 1‐14C nonanal‐9‐oic acid into plasma and human red blood cells lipids
Authors: Dousset N. , Douste‐Blazy L.
Published: November 2006

Nonanal‐9‐oic acid is incorporated principally into plasma phospholipids, whereas oleic acid is incorporated into red cells. This incorporation does not require the presence of adenosine 5′‐triphosphate and Coenzyme A and is carried out in the absence of red cells. the incorporation of nonanal‐9‐oic acid in blood lipids takes place in the first 10 min of incubation.
Dibutyryl cyclic adenosine 3′,5‐monophosphate and brain lipid metabolism
Authors: Weiss Benjamin , Stiller Richard L.
Published: November 2006

It was found that dibutyryl cyclic a denosine 3′,5′‐monophosphate exerted its greatest suppressive effect upon total lipid synthesis in 7–10 day old rat bran slices incubated in the presence of 2‐14C‐acetate, U‐14C‐D‐glucose, and 3‐14C‐DL‐serine. Fractionation of the neutral and polar lipids disclosed that the formation of each of their respective components was reduced to varying extents, thus suggesting that cyclic adenosine 3′,5′‐monophosphate, arising from the hydrolysis of dibutyryl cyclic adenosine 3′,5′‐monophosphate, may control the synthesis of brain lipids by regulating the utilization of acetyl‐coenzyme A.
Cholesteryl ester metabolism in tissue culture cells. I. Accumulation in Fu5AH rat hepatoma cells
Authors: Rothblat George H.
Published: November 2006

Exposure of Fu5AH rat hepatoma tissue culture cells to hyperlipemic rabbit serum results in the accumulation of cellular cholesteryl esters. Accumulation is not a characteristic of all cells in culture, as evidenced by the lack of response of mouse and human fibroblasts. Fu5AH cells grown for 24 hr on 5% hyperlipemic rabbit serum have an 8‐ to 12‐fold increase of cellular cholesteryl esters, small increases in free cholesterol and triglycerides, and no change in phospholipids, when compared to cells grown in normal rabbit serum. Rapid accumulation of cholesteryl esters occurs during the first 8–12 hr of incubation, and maximum cellular concentration is achieved within 24 hr. The maximum level of cellular cholesteryl esters obtained with individual samples of hyperlipemic rabbit serum is correlated with the cholesterol content of the original sera, even when the incubation medium is adjusted to a constant concentration of cholesterol. Heating hyperlipemic rabbit serum (60 C/30 min) does not destroy activity; however, no cholesteryl ester accumulation occurs in heated cells. The stimulatory activity of hyperlipemic rabbit serum primarily is associated with lipoproteins having densities <1.006. High levels of cellular cholesteryl ester are associated with the appearance of cytoplasmic vacuoles containing cholesteryl esters. The increase in cellular cholesteryl esters is accompanied by a decrease of the cholesteryl esters in the growth medium. Cellular cholesteryl esters are not rapidly hydrolyzed or released upon removal of hyperlipemic rabbit serum.
Fatty acids and phospholipids of adult and newborn rat hearts and of cultured, beating neonatal rat myocardial cells
Authors: Rogers C. G.
Published: November 2006

Fatty acids and phospholipids of adult and newborn rat hearts and of cultured, neonatal rat heart cells were determined by gas liquid and thin layer chromatographies. In adult heart, the proportion of linoleic acid was higher and that of palmitic acid lower than in newborn hearts or in cultured cells. The relative amounts of linoleic and arachidonic acids in adult heart were affected by the source and amount of dietary fat. In heart cells, after 3 days in culture, the proportion of arachidonic acid resembled that in the newborn and adult rat hearts but showed a gradual and significant decline with age. The gradual shift in fatty acid composition as the cells aged in culture was attributed to outgrowth of mesenchymal cells (fibroblasts and endothelioid cells) characterized by a low relative proportion of arachidonic acid. The amounts of phospholipids in heart cells after 3 days in culture differed from those in the newborn or adult rat hearts. Phosphatidylethanolamine was highest in adult heart (34% of lipid phosphorus) and lowest in cells (26%); lecithin was higher in newborn heart (43%) than in adult heart (37%) or in cells (39%), while sphingomyelin was higher in cells (8%) than in newborn (5%) or adult heart (3%). Phospholipid levels in cultured heart cells were unrelated to those of serum in the growth medium. The absence of a significant change in phospholipid composition after continued incubation of the heart cell cultures for periods up to 3 weeks reflected the major structural role of these lipid components in cell membranes.
Positional specificity of adipose tissue lipoprotein lipase
Authors: Nilsson‐Ehle P. , Garfinkel A. S. , Schotz M. C.
Published: November 2006

The positional specificity of preparations of lipoprotein lipase derived from rat epididymal adipose tissue was investigated. The enzyme preparations were a crude extract of acetone powder of the whole tissue, partially purified lipoprotein lipase fractions a and b separated by gel chromatography from such an extract, and lipoprotein lipase activity eluted from adipose tissue into a medium by incubation with heparin in vitro. The enzyme preparations were incubated with triglyceride substrate labeled with3H in the glycerol moiety and with14C in the fatty acid esterified to the 2 position of the glycerol. The reaction products were separated by thin layer chromatography. All preparations preferentially hydrolyzed the 1(3) ester bonds of the tri‐ and diglycerides, indicating that, like lipoprotein lipase from other sources, the adipose tissue enzyme has a specificity for the 1(3) position.
Lipids of six cultivated barley (Hordeum vulgare L.) varieties
Authors: Price Phil B. , Parsons John G.
Published: November 2006

The lipids of representative varieties of 2‐row spring, 6‐row spring, and 6‐row winter‐type barleys were studied. Total barley lipids were classified by silicic acid gel column chromatography and separated by thin layer chromatography, and the fatty acid composition was determined by gas liquid chromatography. Total lipid content of the 6 barley varieties ranged from 3.12%–3.56% (dry wt basis). The average values for neutral lipids, glycolipids, and phospholipids were 71, 9, and 20%, respectively. The fatty acid composition of barley was rather typical of plant tissue. The neutral lipids and glycolipids from all the varieties contained a higher percent of linoleic and linolenic (C 18∶2 and C 18∶3) acids than the phospholipid fraction.
A facile synthesis of ergostanol
Authors: Kircher Henry W.
Published: November 2006

Ergosteryl acetate is hydrogenated in one step to ergostanyl acetate over 10% Pd/C in ethyl acetate‐acetic acid at 150 C.
Saussurea candicans seed oil—Alternative source of crepenynic acid
Authors: Smith C. R.
Published: November 2006

Crepenynic acid represents 33% of the constituent fatty acids ofSaussurea candicans seed oil. This important acetylenic acid, after isolation by countercurrent distribution, was characterized unambiguously by derivatives and by degradative procedures.
Free and protein‐bound gangliosides in triton X‐100 extracts from rat brain
Authors: Brunngraber Eric G. , Ziboh Vincent A.
Published: November 2006

Gangliosides that are extracted from brain tissue samples with Triton X‐100 exist in a free form and as a ganglioside‐protein complex. The two forms can be separated by diethylaminoethyl‐cellulose chromatography. Whole brain tissue yields only ganglioside‐protein complexes. Crude mitochondrial and microsomal fractions and synaptosome‐enriched fractions yield both free and protein‐bound gangliosides. The myelin and mitochondria‐enriched fractions yield only free gangliosides. The isolation of ganglioside‐protein complexes and free gangliosides appears to be dependent upon the nature of the starting material.
Lipids of cultured hepatoma cells: III. Triglyceride and phosphoglyceride biosynthesis in minimal deviation hepatoma 7288C
Authors: Wiegand Rex D. , Wood Randall
Published: November 2006

Minimal deviation hepatoma 7288 C cells were cultured on media containing 25% serum to the confluent stage. The growth media was replaced with serumfree media containing 1‐14C‐palmitate, and incubations were continued for 0.75, 1.5, 3, 6, 12, and 24 hr. The distribution of radioactivity among the major neutral lipids and phosphoglycerides was determined for cells and culture media. Radioactivity in individual fatty acids of cellular triglyceride, phosphatidylcholine, and phosphatidylethanolamine also was determined. After 24 hr, more than 95% of the administered radioactivity was recovered in neutral and phosphoglycerides, indicating that only a small amount of the fatty acid was oxidized. At any time period examined, over 80% of the incorporated radioactivity was found in triglyceride, phosphatidylcholine, and phosphatidylethanolamine. Incorporation of the label into cellular triglyceride and phosphatidylcholine plateaued at 12 hr, whereas incorporation of radioactivity into phosphatidylethanolamine still was increasing at 24 hr. In contrast, during the entire incubation period the relative distribution of14C among esterified lipid classes in the culture media remained constant. Elongation of palmitic acid to stearic acid and its subsequent desaturation to oleic acid suggests that these cells possess an active elongation and monoenoic desaturation system. Labeled glycerol ether diesters were not detected in the cells or culture media. Positional distribution of the14C label in the triglyceride and phosphatidylcholine suggests that minimal deviation hepatoma cells do not exhibit diglyceride selectivity in the biosynthesis of these two lipid classes.
Staphylococcal lipases
Authors: Vadehra D. V.
Published: November 2006

A lipase rich fraction was isolated from the cell free supernatant of 24 hr broth culture ofStaphylococcus aureus B‐120, grown in trypticase soy broth at 37 C. Lipase from the cell free supernatant was precipitated with equal volumes of absolute ethanol. This fraction was purified further by differential precipitation at pH 8.6 and 4.3. Subsequent purification, using Sephadex G‐200 and BioGel 300, yielded a preparation with 350–450‐fold increase in specific activity. The purified lipase had an optimum pH of 8.5 at 37 C. The electrophoretic mobility was‐7.78×10−5 cm2/volt/sec. The sedimentation coefficient for the two peaks was 2.85 and 8.5, respectively, and the mol wt was 100,000. The purified lipase hydrolyzed a variety of natural oils and fats. The amount of free fatty acids liberated from hydrogenated soybean oil (iodine value<3) was one‐third compared to natural oils and fats. Gas chromatographic analysis of hydrolyzed synthetic triglyceride, with palmitic, stearic, and oleic acids at the rac 1, 2, and 3 positions, respectively, indicated that the enzyme was capable of hydrolyzing the glycerolfatty acid bonds at all three positions. The yield was 40% palmitic, 20% stearic, and 39% oleic acids. Formaldehyde, mercaptoethanol, cysteine, glutathione, and terramycin had inhibitory effects upon lipase activity while hydrogen peroxide, streptomycin, and sodium taurocholate had a stimulatory effect upon the activity.
Some properties of an exocellular lipase fromRhizopus arrhizus
Authors: Benzonana Gilbert
Published: November 2006

Rhizopus arrhizus, a mold of the mucor family, excretes an active lipase when cultured properly. This lipase has a mol wt of 43,000 and a high carbohydrate content, Upon storage at 4C in aqueous solution, lipase I is slowly converted by proteolysis to a more cationic form, lipase II, which has a lower mol wt (32,000) and no carbohydrate.Rhizopus lipase shows the same positional specificity on long chain triglycerides as pancreatic lipase; it has no preferential side chain specificity against oleic vs. palmitic acid. Like pancreatic lipase,Rhizopus lipase acts on micelles of short chain triglycerides and is inhibited by high concentrations of bile acids; however, in the presence of deoxycholate,Rhizopus lipase does not require added Ca++ for full activity.
Analysis of autoxidized fats by gas chromatography‐mass spectrometry: V. Photosensitized oxidation
Authors: Frankel E. N. , Neff W. E. , Bessler T. R.
Published: November 2006

The role of singlet oxygen in oxidation was studied by analyzing hydroperoxide isomers in unsaturated fats and esters by gas chromatography‐mass spectrometry (GC‐MS). On oxidation photosensitized with methylene blue at 0 C, methyl oleate produced a 50–50% mixture of 9‐ and 10‐hydroperoxides, linoleate a mixture of 66% conjugated (9+13) and 34% unconjugated (10+12) hydroperoxides, and linolenate a mixture of 75% conjugated (9+12+13+16) and 25% unconjugated (10+15) hydroperoxides. Cottonseed, safflower, and corn oil esters showed, as in soybean esters, the presence of varying amounts of 12‐hydroxy esters derived from the corresponding hydroperoxide at low peroxide values. Since these oils do not contain linolenic acid, a likely source of the 12‐hydroperoxide is linoleic acid by photosensitized oxidation. Several lines of evidence support the conclusion that singlet oxygen may contribute to the unique hydroperoxide composition of vegetable oil esters at low levels of oxidation. In the presence of photosensitizers such as methylene blue and chlorophyll, the unique hydroperoxide composition (high levels of 10‐ and 12‐hydroperoxides) obtained in soybean esters was similar to that produced by oxidation at low peroxide values. In contrast, a normal hydroperoxide composition was produced, as expected from the fatty acid composition of soybean oil esters, when singlet oxygen quenchers such as β‐carotene and α‐tocopherol were used and when the esters were treated with carbon black to remove natural photosensitizers. GC‐MS analyses of the derived unsaturated alcohols provided indirect evidence for 12‐hydroperoxy‐9,13‐diene in soybean esters as expected by photosensitized oxidation of linoleate.
Incorporation of dietarycis andtrans octadecenoate isomers in the lipid classes of various rat tissues
Authors: Wood Randall
Published: November 2006

The percentage distribution of the geometrical and positional isomers in the hexadecenoates and octadecenoates isolated from triglycerides, phosphatidylcholines, and phosphatidylethanolamines of brain, heart, kidney, liver, lung, muscle, spleen, and adipose tissues from rats maintained four weeks on a semipurified diet supplemented with 15% partially hydrogenated safflower fatty acids, has been determined. Except for brain, octadecenoate percentages were increased in each of the lipid classes of all the tissues by the dietary fat. Although the diet did not contain detectable hexadecenoates, the 16∶1 fraction from the lipid classes of all the tissues was composed of 10–70% of thetrans isomers, indicating chain shortening of the dietary octadecenotes. Distribution ofcis andtrans positional isomers in triglyceride hexadecenoates was approximately the same in all tissues. Relatively high percentages of the Δ9, Δ10, and Δ11 isomers were observed, but the Δ8 was the predominatingtrans hexadecenoate isomer, indicating preferential chain shortening of thetrans δ10 octadecenoate.Trans octadecenoates were found in all tissues, but concentrations were dependent on tissue and lipid class. The distribution of thecis andtrans octadecenoate isomers was similar in all the tissue triglycerides, with the distribution of thetrans isomers resembling the diet. In contrast, the percentage distribution of thetrans octadecenoates in the phospholipid classes differed dramatically from the diet, and the distribution was dependent on both the tissue and lipid class. The Δ12, Δ13, and Δ14trans octadiet, suggesting an accumulation of these isomers. Although thecis Δ10 octadecenoate was a significant dietary component, this isomer was not incorporated significantly into any lipid class of any tissue. The metabolic fate of this isomer remains unknown.
Analysis of the conjugated trienoic acid containing oil fromFevillea trilobata by13C nuclear magnetic resonance spectroscopy
Authors: Tulloch A. P. , Bergter L.
Published: November 2006

Oil ofFevillea trilobata has the composition palmitic acid 31%, stearic acid 12%, oleic acid 11%, linoleic acid 7%,cis,trans,cis 9,11,13‐octadecatrienoic acid 30% andcis,trans,trans‐9,11,13‐octadecatrienoic acid 9%. The oil was analyzed and components identified by13C NMR spectroscopy; the composition was also confirmed by conventional methods. Assignment of13C NMR signals of conjugated trienoic acids is discussed and it is shown that mixtures of isomeric conjugated acids can be analyzed by this method.
Effects of membrane fatty acid composition on sodium‐independent phenylalanine transport in Ehrlich cells
Authors: Im Wha Bin , Deutchler Jon T. , Spector Arthur A.
Published: November 2006

We have examined Na+‐independent phenylalanine transport in Ehrlich cells having different degrees of membrane fatty acid saturation. These differences were produced by growing the cells in mice fed a fat‐free chow supplemented with either sunflower seed oil or coconut oil. Plasma membranes isolated from the cells grown on sunflower oil were enriched with polyenoic fatty acid, especially 18∶2, whereas those isolated from the cells grown on coconut oil were enriched in monoenoic fatty acids, primarily 16∶1 and 18∶1. Arrhenius plots of phenylalanine uptake showed two transitions. The temperatures of these transitions were different in the two cell preparations; 17 C and 24 C for the cells enriched in polyenoic fatty acids, 19 C and 28 C for those enriched in monoenoic fatty acids. Therefore, this transport system is sensitive to changes in the fatty acid composition of the lipid phase in which it operates. The activation energies, however, were the same in both cell preparations; 14, 8 and 4 kcal/mol. There also was no significant effect of the lipid modifications on either the K′m or V′max of this transport process. The K′m for phenylalanine uptake from a choline medium remained constant as the temperature was raised from 17 C to 37 C, whereas the V′max showed about a two‐fold increase in both cell types. Phenylalanine exodus from the cells into an amino acid‐free suspending medium, analyzed using first‐order kinetics, also was not influenced by these membrane fatty acid modifications. The changes in the transition temperatures probably reflect differences in the degree of fatty acid unsaturation of lipids that surround and interact with the phenylalanine carrier. Such differences, however, do not appreciably influence the catalytic activity of this transport system.
Response of free and esterified plasma cholesterol levels in the mongolian gerbil to the fatty acid composition of dietary lipid
Authors: Mercer Nina J. H. , Holub Bruce J.
Published: November 2006

The present study was undertaken to investigate the potential suitability of the Mongolian gerbil as a useful animal model to study the effects of dietary fats on plasma cholesterol levels. Semipurified diets containing either 20% lard, 20% safflower oil, or 19.5% beef tallow +0.5% safflower oil were equalized to contain 0.01% cholesterol and 0.05% plant sterol and were fed for a four week experimental period. The proportions of total calories contributed by fat, protein and carbohydrate (starch/sucrose ratio of 2∶1) were 40, 14 and 46%, respectively, so as to approach the distribution of calories within the average North American diet. Free, esterified, and total plasma cholesterol levels of male gerbils were determined weekly by gas liquid chromatography after drawing blood via a serial sampling technique. After 1, 2, 3, and 4 weeks of feeding the experimental diets, total cholesterol levels were lowest in the safflower oil fed animals; the corresponding values were 19–64% greater in gerbils fed lard and 68–91% greater in those consuming the beef tallow diet. Cholesterol in the free form generally responded more dramatically to the type of dietary lipid than did cholesterol in the ester form. Irrespective of the type of dietary lipid or the length of the feeding trial, 18–23% of the total plasma cholesterol was in the free form and 77–82% was present as the ester. In view of the similarity to the human of the relative proportions of free versus esterified cholesterol, the type of cholesteryl esters, and their response to dietary manipulation, the gerbil appears to be a useful animal model for studying the regulatory effect of dietary lipid on plasma cholesterol levels.
Lipid binding properties of a factor necessary for linoleic acid desaturation
Authors: Leikin Alicia I. , Nervi Anibal M. , Brenner Rodolfo R.
Published: November 2006

Suspension and centrifugation of crude microsomes of rat liver in low ionic strength solution separated a soluble protein fraction that is necessary for the full activity of the linoleic acid desaturase. The fraction partially purified through Sephadex G‐150 still retains lipids which are mainly constituted by phosphatidylcholine. Linoleic acid predominates in the fatty acid composition. By NaCl gradient centrifugation and electrophoresis in gelatinized cellulose acetate, the factor behaves like a lipoprotein. The factor binds linoleic acid and linolyl‐CoA that are desaturated to γ‐linolenic acid when incubated with washed microsomes. Albumin does not replace the factor.
Kidney lipids: Changes caused by dietary 9‐Trans, 12‐Trans‐octadecadienoate
Authors: Kinsella J. E. , Yu P. H. , Mai J. B.
Published: November 2006

Trans, trans‐linoleate at 50 and 100% of dietary fat decreased kidney size and altered its composition.Trans, trans‐linoleate as the sole source of dietary fat imparied growth and caused more severe symptoms of essential fatty acid deficiency than was observed with hydrogenated coconut oil (HCO). The concentration of renal cholesterol, phospholipids (PL), triglycerides (TG) and cholesteryl esters (CE) were also decreased. Linoleic (18∶2), homo‐γ‐linolenic acid (20∶3n6) and arachidonic acid (20∶4n6) were significantly depressed in lipid classes, especially in PL and CE, by dietarytrans, trans‐linoleate. The increase in eicosatrienoate (20∶3n9), especially in PL and CE of kidneys of rats fed HCO (essential fatty acid deficient), was slight in rats fed 100%trans, trans‐linoleate, indicating that thetrans, trans acid probably inhibited acyl elongation and desaturation.
Autoxidation of fatty acid monolayers adsorbed on silica gel: III. Effects of saturated fatty acids and cholesterol
Authors: Wu Guey‐Shuang , Stein Robert A. , Mead James F.
Published: November 2006

Autoxidation of fatty acid monolayers on silica consisting of multiple components to simulate biomembranes has been studied by the rate of fatty acid disappearance and the products formed. When palmitic acid was incorporated into linoleic acid monolayers, the decrease in rate was proportional to the amounts of plamitic acid present. The protective effect of the saturated fatty acid diminished rapidly as the chain length of the saturated fatty acid decreased below C12. With acids of medium chain length, C12 was more effective than C16. In pure linoleic acid monolayers, when the surface coverage was reduced to only 5% of the available adsorption sites, and in the case of palmitic acid‐linoleic acid monolayers, the rate dropped drastically and the major identified product formed was hydroxyepoxyoctadecenoic acid. On the contrary, the major product formed in the case of saturated monolayers of pure linoleic acid was a mixture of unsubstituted epoxy acids. The inclusion of cholesterol in linoleic acid monolayers increased the rate of disappearance of linoleic acid slightly, whereas cholesteryl acetate decreased the rate. The protective effect exerted by cholesteryl acetate appeared to be similar to that of palmitic acid.
Isolation of sterol mutants inChlamydomonas reinhardi: Chromatographic analyses
Authors: Bard M. , Wilson K. J. , Thompson R. M.
Published: November 2006

Several sterol mutants ofChlamydomonas reinhardi were isolated by selecting for single colonies resistant to the polyene antibiotic, nystatin. The sterol profiles of three isolates—KD7, KD16, and KD21—as well as a wild type strain (137C) were determined by gas liquid chromatography and mass spectrometry. The wild type strain contained ergosterol (C28‐5,7,22‐triene) as the predominant sterol, with smaller amounts of a C28‐5,7‐diene, a C28‐7‐ene, and C‐24 ethyl analogs of these three sterols. The three mutants had altered sterol composition, but none required exogenous sterol for growth. KD7 contained a C28‐5,7,22,25‐tetraene, a C28‐5,7,25‐triene, a C28‐7,25‐diene, and three C‐24 ethyl analogs. The lesion in KD7 is apparently an inability to reduce the C‐25 double bond required for the biosynthesis of ergosterol and an ethyl analog. The predominant sterols accumulated by KD16 and KD21 were a C28‐5,7‐diene, a C28‐7‐ene, and C‐24 ethyl versions of these two sterols, suggesting that these strains are 22(23)‐desaturase mutants.
Δ15, 18‐tetracosadienoic acid content of sphingolipids from platel and erythrocytes of animals fed diets high in saturated or polyunsaturated fats
Authors: Pitas R. E. , Nelson G. J. , Jaffe R. M. , Mahley R. W.
Published: November 2006

The effect of diets high (15%) in saturated (beef tallow) or polyunsaturated (corn or cottonseed oil) fatty acids on the fatty acid composition of sphingomyelin from canine erythrocytes and platelets and sphingomyelin and neutral glycosphingolipids of swine erythrocytes was determined. Sphingolipids of platelets and erythrocytes from animals fed high levels of corn or cottonseed oil exhibited a dramatic alteration in their fatty acid composition, most notable of which was a 50% reduction in nervonic acid (24∶1ω9) as compared to levels observed in control or tallow fed animals. This decrease was compensated for by a quantitatively similar increase in a C24 dienoic acid. The long chain dienoic acid was isolated by silver nitrate thin layer chromatography and determined by analysis of its oxidation products to be Δ15, 18‐tetracosadienoic acid (24∶2ω6). When the animals were fed the diets high in polyunsaturates, the 24∶2ω6 represented 13, 20, and 9% of the sphingomyelin fatty acids from canine erythrocytes, platelets, and swine erythrocytes, respectively, and 5% of the neutral glycosphingolipid fatty acids of swine erythrocytes. In contrast, the 24∶2ω6 represented less than 4% of the total cellular sphingolipid fatty acids in animals fed the control or high beef tallow diets. The 24∶1ω9 in the sphingolipids of the animals fed the polyunsaturated diet was roughly equal to that of 24∶2ω6, whereas in the sphingolipids of animals fed the control or saturated fat (beef tallow) diet, the 24∶1ω9 was twice these values. Since sphingomyelin is a membrane component, the increase in unsaturation (24∶2ω6) in its fatty acid moiety induced by dietary polyunsaturates may affect membrane fluidity and may alter membrane properties.
Effects of synthetic and natural lysophosphatidic acids on the arterial blood pressure of different animal species
Authors: Tokumura Akira , Fukuzawa Kenji , Tsukatani Hiroaki
Published: November 2006

Intravenous injection of lysophosphatidic acid was found to cause hypertension in rats and guinea pigs, but hypotension in cats and rabbits. The potencies of the pressor and depressor effects of synthetic lysophosphatidic acids in rats and cats depended on their chain length and the degree of unsaturation of their fatty acyl moieties.
Liver and thymus lipid composition in AKR mice with and without lymphomas
Authors: Kitada Shinichi , Mwasi Lawrence , Mead James F. , Hays Esther F.
Published: November 2006

Lipid composition of liver and thymus in controls, early stage lymphoma, and advanced stage lymphoma‐bearing AKR mice was studied. There was a significant decrease in the liver total lipid content in mice with advanced lymphoma, whereas in the early stages, no quantitative change was seen. In livers of mice with advanced stage lymphoma, there was a significant decrease in the nonpolar fraction. The decrease was in triglyceride, whereas the cholesterol fractions were relatively increased though highly variable. There was an increase in the polar lipid/nonpolar lipid ratio in the advanced lymphoma livers and a very large increase in the polar lipid/triglyceride ratio, indicating that the decrease in total lipid in these livers was largely in the triglyceride fraction. Similar changes were seen in the thymus, in which the lipid composition reflected the transformation from normal to malignant cells.
Identification of vasopressor phospholipid in crude soybean lecithin
Authors: Tokumura Akira , Fukuzawa Kenji , Akamatsu Yasue , Yamada Sadaji , Suzuki Tetsuya , Tsukatani Hiroaki
Published: November 2006

The vasopressor phospholipid in crude soybean lecithin was isolated by column chromatography on Sephadex LH‐20. It represented 0.1% of crude soybean lecithin. The isolated phospholipid was identified to be lysophosphatidic acid by gas chromatography‐mass spectrometry analysis of TMS‐deacylated product and acetolysis product. Nuclear magnetic resonance analysis favored the 1‐monoacyl isomer over the 2‐isomer. By enzymic determination with L‐3‐glycerophosphate dehydrogenase, the isolated phospholipid was identified as 1‐monoacyl‐L‐3‐glycerophosphate. Gas chromatographic examination revealed that it was composed of a large percentage of unsaturated fatty acids, especially linoleic acid. The activity of isolated lysophosphatidic acid was slightly less than that of synthetic 1‐linoleoyl‐L‐3‐glycerophosphate.